WO1993019581A1

WO1993019581A1 - Computer controlled seedling transfer apparatus

Info

Publication number: WO1993019581A1
Application number: PCT/US1992/002558
Authority: WO
Inventors: Gaines E. Miles; Stephen M. Beam; John R. Brubaker; Gregory John Treece; Tony D. Wade
Original assignee: Robotic Solutions, Inc.
Priority date: 1992-03-27
Filing date: 1992-03-27
Publication date: 1993-10-14

Abstract

A computer controlled seedling transfer apparatus (10) includes a pair of conveyors (13, 20) for supporting a seed flat (S) and pot flat (P). Associated indexing mechanisms (27, 47) translate the flats along the conveyor to align flat recesses with a transfer station (TS) between the flats. A seedling transfer mechanism (62) above the conveyors moves transversely between the flats, and includes extendable gripping fingers (75) for gripping, transferring and transplanting a seedling. A computer (100) controls the movement of the indexing mechanisms (27, 47) and seedling transfer mechanism (62) to optimize the seedling transfer operation based on the condition of the flat recesses sensed by a camera (92). In a further embodiment (110), a pair of seed flat bed (113) straddle a single pot flat bed (120). A pair of seedling transfer mechanisms (170) simultaneously or sequentially extracts and transplants seedlings from both seed flats into the single pot flat. A seedling ejector mechanism (155) is also provided to separately eject individual seedlings.

Description

COMPUTER CONTROLLED SEEDLING TRANSFER APPARATUS

BACKGROUND OF THE INVENTION

The present invention relates to a computerized transfer apparatus. In particular, the invention concerns an apparatus for transferring plant seedlings between seedling growing trays.

In commercial green houses, plants are typically grown in what is called a seed flat which is essentially a tray having a number of small cavities containing a plug of soil. The seed flat is seeded with a particular plant which is tended until the seedling has grown large enough for transplanting. At that point, the seedling is ready to be transferred to a pot flat which is generally provided to commercial outlets. Typically, the pot flat will have fewer recesses than the seed flat but each recess will have a larger volume to hold more soil and accommodate a larger root ball as the seedling continues to grow. The smaller recesses in the seed flat save grower's space and reduces watering reguirements over the pot flat. However, commercial considerations dictate that the seedling be transferred to a pot flat.

A typical seed flat might measure 14 recesses across and 29 recesses along its length so that up to 406 seedlings can be grown in a single seed flat. A typical pot flat, on the other hand, may have only 4 recesses across its width and 12 recesses along its length, for a total of 48 recesses to receive seedlings transplanted from the seed flat. The transfer of seedlings from the seed flat to the pot flat has presented a unique problem to the industry. It is important that the transfer occur with minimal disturbance to the plant seedling and its root ball. Moreover, since the pot flat is often sold directly to the final consumer, the pot flat must be completely filled with seedlings. In prior transfer apparatus, errors in the seed flat are generally propagated to the pot flat. These errors may include an empty recess in the seed flat or a badly oriented seedling. On the other hand, the need for higher transfer rates has tended to restrict the ability of prior devices to check for and correct these errors. Prior apparatus have been forced to sacrifice speed for efficiency, or vice versa. There is a need in the art for a seedling transfer apparatus that minimizes the disturbance to the plant seedling, increases the transfer rate between the seed flat and the pot flat, and improves the efficiency of these transfers. There is also a need for such an apparatus that is fully automatic so that only minimal human interaction is required in the transfer operation.

SUMMARY OF THE INVENTION

The present invention resides in an apparatus for sequentially transferring plant seedlings from a seed flat, having a number of plug recesses initially containing a number of plant seedlings therein, to a pot flat, having a number of receiver recesses to be filled with seedlings. Separate conveyors are provided for supporting the seed flat and the pot flat to permit movement of the flats along longitudinal axes. A seedling gripper includes resilient fingers for releasably gripping the seedling to remove the seedling from a plug recess of the seed flat and to release the seedling in a receiver recess of the pot flat. A seedling transfer mechanism moves the seedling gripper between the seed flat and the pot flat along a transfer axis that intersects, and is preferably perpendicular to, the longitudinal axes. Flat gripping and moving mechanisms are provided for indexing the seed and pot flats on their respective conveyors to sequential recesses. A computer controller controls the motion of the flat moving mechanisms so that the plug recesses are sequentially oriented along said transfer axis. A sensor is provided to determine whether a plug was successfully transplanted. If the transplant was not successful, the computer instructs the transferring apparatus to repeat the planting step into a particular pot recess until a successful transplant occurs. The computer controller directs the movement of the flat moving mechanisms and seedling transfer mechanism to minimize the travel distance of the seedling during a transfer.

In another aspect of the invention, the seedling gripper includes a flexible web spanning between the fingers and forming a web pocket between the fingers and web. When the fingers grip a seedling, the stem and flower of the seedling is slightly bent by the web so that the seedling does not hang up on the fingers when the seedling is released in the

SUBSTITUTE SHEET pot flat receiver recess. A water jet is provided as another feature of the invention to facilitate removal and replanting of the seedling, and in another embodiment a water jet is provided to dibble the soil in the receiver recess. In one embodiment of the seedling transfer mechanism, the fingers are permitted to move only along one horizontal degree of freedom along the transfer axis. The computer controller prescribes a transfer move sequence in which the fingers grab and remove a seedling from a plug recess, and transfer the seedling and replant it in the next sequential receiver recess in the pot flat. After the seedling has been replanted, the fingers are moved away from the seedling until the seedling clear the web pocket, and the pot flat indexed to provide clearance for the fingers to return to the seed flat without contacting any replanted seedlings in the pot flat.

In another embodiment of the seedling transfer mechanism, a rotary motor is provided to rotate the gripper fingers to change the orientation of the web pocket. During the transverse move between the seed and pot flats, the fingers are rotated so that the web pocket faces the destination flat. The transfer move sequence for this rotary version does not require special indexing of the pot flat to clear the gripper fingers and web. In one preferred embodiment of the invention, the transfer move sequence provides for minimizing the travel distance of the seedling during transfer, while preventing the gripper fingers from disrupting seedlings in the seed flat or pot flat. Thus, the seedlings are removed from the seed flat along longitudinal columns, and they are replanted in the pot flat along transverse latitudinal rows.

In an alternative embodiment of the invention, a seedling transfer apparatus is provided which includes a pair of seed flat beds straddling a single pot flat bed. A number of seed flats can be supported by each of the seed flat beds to provide seedlings for transfer into a single pot flat residing on the pot flat bed. Mechanisms for moving the seed and pot flats on their respective beds are provided which include a chain and cleat assembly. A pair of chains are associated with each bed with a cleat spanning across the width of the bed. The cleat is adapted to push a flat resting on the corresponding seed or pot flat bed.

The seed beds and pot bed are adapted to mate with input and discharge conveyors. More specifically, the pot bed includes a pusher roller which is used to pull a pot flat onto the bed. A chain and cleat arrangement is used to pull seed flats from conveyors onto a corresponding seed bed.

In a further aspect of this embodiment, a seedling ejector assembly is provided which includes a single ejector pin movably mounted on a carriage. The carriage can be moved laterally under the seed flat bed to one of the columns of a corresponding seed flat. Thus, rather than ejecting all of the seedlings in a row of the seed flat, only a single seedling is ejected from the seed flat with this particular mechanism. Moreover, the mechanism provides means for completely ejecting the seedling from the seed flat into the open arms of the transfer fingers. The seedling is supported by a needle extending into the root ball.

In yet another aspect of the invention, a seedling gripper assembly is provided which uses an air cylinder to reciprocate the seedling fingers up and down relative to the seed or pot flats.

The invention further contemplates a series of transfer moves taking full advantage of the two seed flats feeding into a single pot flat. With this sequence of transfer moves, the speed with which a single pot flat is filled can be greatly increased. The transfer apparatus contemplates the use of two seedling gripper mechanisms to alternatively or simultaneously extract seedlings from two seed flats on the two seed flat beds, and sequentially or simultaneously transferring these seeds into corresponding empty recess locations in the pot flat. For example, one transfer apparatus can be transplanting a seedling into the pot flat while the other transfer apparatus is simultaneously grabbing a new seedling.

It is one object of the invention to provide a seedling transfer apparatus that is less traumatic to seedlings during the transfer than other prior art devices. Another object is to provide such an apparatus that is capable of high transfer speeds at virtual 100% efficiency.

A further object is to provide a transfer apparatus that does not propagate errors in the seed flat onto the pot flat. Yet another object is to supply an apparatus that can detect whether a transfer was successful and direct future transfer move sequences accordingly. Other objects, as well as the benefits, of the present invention can be readily discerned from the following written description and accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an orthographic view of the seedling transfer apparatus of the present invention.

FIG. 2 is a partial end view of the apparatus of FIG. 1, in which only the seed flat conveyor and gripper mechanism are shown.

FIG. 3 is an enlarged detail view of the pot flat gripper mechanism shown in FIG. 1.

FIG. 4 is an enlarged orthographic view of the plant transfer mechanism of one embodiment of the invention shown in FIG. 1.

FIG. 5 is a front view of a plant transfer mechanism of another embodiment of the invention.

FIG. 6 is a schematic representation of transfer move sequences for the seedling transfer apparatus of one embodiment of the invention.

FIG. 7 is a schematic representation of transfer move sequences for a seedling transfer apparatus of another embodiment of the invention. FIG. 8 is an orthographic projection of a seed and pot flat moving mechanism for a transfer apparatus of an alternative embodiment of the invention.

FIG. 9 is an orthographic view of seedling ejector assembly of an alternative embodiment of the invention. FIG. 10 is an orthographic view of a seedling gripper assembly according to another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

One embodiment of the computer controlled seedling transfer apparatus 10 of the present invention is shown in FIG. 1. The apparatus includes a frame 11 which comprises a number of beam elements to provide lateral and horizontal support for the apparatus. A seed conveyor 13 and pot conveyor 20 are supported by the frame 11. The seed conveyor 13 includes opposite side rails 14 and 15 which rotatably support a number of freewheeling rollers 16. The pot conveyor 20 also includes opposite side rails 21 and 22 supporting freewheeling rollers 23. The seed conveyor 13 and pot conveyor 20 can be of conventional construction for non-driven conveyors. In one specific embodiment, the conveyors can be obtained from Roach, Inc. as product no. 138A-12-1 1/2-60. As shown in FIG. 1, a seed flat designated as S is supported by the seed conveyor while a pot flat P sits upon the pot conveyor. Both flats are free to translate along the respective conveyors, since the rollers 16 and 23 are freewheeling. The relative heights of the seed and pot conveyors can be adjusted to account for variations in seed flat and pot flat heights.

Each of the flats is moved by separate means for moving the flats supported by the conveyors. The seed flat is indexed by a moving means, such as indexing mechanism 25, which is associated with the seed conveyor 13, as shown more clearly in FIG. 2. The indexing mechanism 25 includes a support beam 26 which is mounted to the frame 11. A flat gripper assembly 27 includes oppositely acting edge gripping fingers 28 which are adapted to grip the edge of the seed flat S. A gripper 29 controls the clamping operation to open and close the gripping fingers 28. The gripper 29 is affixed to a carriage 30 which is connected to a drive belt 32. The drive belt is drivenly engaged around a pulley 33, which is rotated by a drive motor 34. Another pulley, not shown, is situated at the opposite end of the support beam 26 (FIG. 1), so the belt spans between two pulleys over most of the length of the beam 26. The carriage, while being driven by the drive belt 32, is supported by a pair of guide rods, not shown, extending substantially along the length of the support beam 26.

As configured, rotation of the pulley 33 by the drive motor 34 causes the drive belt 32 to rotate, thereby translating the carriage 30 along the guide rods and indexing the flat gripper assembly 27. When the gripper 29 is actuated to grip the seed flat S, the seed flat can be indexed along the seed conveyor 13 in a direction parallel to its longitudinal axis. An articulated cable support 36 carries the electrical cable that supplies power and control signals to and from a computer controller 100. The cable support 36 keeps the electrical cables free from the drive belt 32 and provides full support for the cables as the indexing mechanism 25 translates. A similar mechanism is provided for indexing the pot flat. In particular, the moving means constitutes an indexing mechanism 45 which includes a support beam 46 which is mounted on a frame 11. A flat gripper assembly 47 includes rim gripping fingers 48, as shown more clearly in FIG. 3. The rim gripping fingers 48 in the preferred embodiment include a gripping pin 49 on the lower finger to grip under the rim of the pot flat P. The rim gripping fingers 48 are mounted to edge gripping fingers 48', which are identical to the edge gripping fingers 28 for the seed conveyor indexing mechanism.

An air actuated gripper 50 controls the opening and closing of the edge gripping fingers 48', which controls the operation of the rim gripping fingers 48. The gripper 50 is mounted to a carriage 51 which is slidably mounted on carriage guide rods 52. The carriage guide rods 52 are mounted on the support beam 46. It is understood that the guide rods referred to in connection with the indexing mechanism 25 for the seed flat side of the apparatus are identical to the carriage guide rods 52, and are mounted on support beam 26.

Returning again to indexing mechanism 45, a drive belt 54 is mounted over a pulley 55 at one end of the support beam 46 and a drive pulley, not shown, at the opposite end of the beam. A drive motor 56 rotates the drive pulley 55 to cause the drive belt to translate, thereby indexing the carriage 51 and pot flat gripper assembly 47 with it. A cable support 58, similar to cable support 36, is mounted to the carriage 51 to the electrical cables to and from the computer controller 100 and the gripping motor 50. Among these electrical cables are cables fed an edge sensor 59. The edge sensor 59 is mounted to the carriage 51 so that it moves along with the pot flat gripper assembly. The edge sensor 59 is provided to sense the leading edge of the pot flat P as it rests on the conveyor 20. The edge sensor can be an optical sensor, such as Model No. E3S-D510E4 provided by Omron Corp. A similar edge sensor 38 (FIG. 2) is mounted to the carriage 30 of the indexing mechanism 25 for the seed flat gripper assembly 27.

In one specific embodiment, the drive motors 34 and 56 are stepping motors that are capable of step-wise rotational otion. Alternatively, the motors could be close looped servo motors or other similar motors capable of providing of indexed, or step-wise, motion. The grippers 29 and 50 can be of the type provided by Compact Air Products as Model No. 112. The rim gripping fingers 48 can be formed of thin wall stainless steel so that there is some flexure of the gripping fingers to adequately grip the pot flat P.

Referring again to FIGS. 1 and 2, the seed flat conveyor 13 includes a seedling ejector 40 at approximately the midpoint of the conveyor, or more specifically at the seedling transfer station TS. The seedling ejector 40 includes a number of ejector pins 41 which are raised and lowered by way of a pair of ejector air cylinders 42. The pins 41 are preferably mounted on a bar 43 which is mounted on actuator rods 44 of the ejector cylinders 42. The cylinders 42 are supported by the support frame 11 directly beneath the conveyor 13. In one specific embodiment, the ejector cylinders 42 are pneumatic cylinders, such as Model No. BFHD34X12 sold by Compact Air Products. The ejector pins 41 are situated to align with drain openings typically found in the base of the seed flat recesses. In their retracted position, the ejector pins permit the seed flat S to move over the ejector 40. When the ejector motors 42 are stroked, the ejector pins 41 move into the drain holes at the base of the seed flat S to push the seedling plug upward from the plug recess PR. Pushing the seedling plug upward facilitates gripping the seedling, as explained more fully herein.

The transfer apparatus 10 of the present invention also includes a seedling transfer mechanism 62 which is carried by an overhead gantry 60 attached to support frame 11. The seedling transfer mechanism 62 is mounted on a carriage 64 which is slidably supported on guide rods 65. The guide rods are mounted to the overhead gantry 60. A drive belt 67 is engaged around a drive pulley 68 and an idler pulley 69. The drive pulley 68 is connected to a motor 70, in a manner similar to the pulley and motor combinations for the indexing mechanisms 25 and 45. The drive belt 67 performs in the same manner to translate the carriage 64 along the overhead gantry 60. In this preferred embodiment, the overhead gantry 60 is fixed relative to the seed conveyor and pot conveyor. Thus, the gantry permits transverse motion of the seedling transfer mechanism 62 along one fixed axis, or transfer axis, which axis is preferably perpendicular to the longitudinal axes of the seed conveyor 13 and pot conveyor 20 and to the direction of indexed travel of the seed flat S and pot flat P.

The seedling transfer mechanism 62 is shown in more detail in FIG. 4. In the one embodiment, a pair of opposite plant gripper fingers 75 are provided. These plant gripper fingers 75 are attached to edge gripper fingers 76, which are in turn controlled by a gripper air cylinder 78. The edge gripper fingers 76 and air cylinder 78 are identical to the fingers 28 and air cylinder 29 of the seed flat indexing mechanism 25. The plant gripper fingers 75 are formed of a spring steel to provide some resilience and flexibility while permitting adequate gripping force to grip the root ball of a seedling. The plant gripper fingers 75 are also stiff enough to be plunged into the soil in a seed flat plug recess PR. As shown in FIG. 5, the gripper fingers 75 are angled toward each other. Upper portions 75a of the fingers are wider apart than the lower gripping portions 75b in order to accommodate the flower of the seedling. Angling the lower gripping portions 75b inward can increase the resilient gripping force on the root ball of the seedling. The gripper air cylinder 78 is affixed by extension rods 81 to an extension air cylinder 80, which provides means for extending and retracting the plant gripper fingers 75. When the extension rods 81 are extended, the plant gripper fingers 75 are plunged into the soil in the plug recess PR. The gripper air cylinder 78 is then actuated to draw the plant gripper fingers 75 together around the seedling. The extension air cylinder 80 is actuated to retract the extension rods 81, and thereby pull the plant gripper fingers and seedling out of the seed flat S. In one embodiment of the seedling transfer mechanism 62, the extension cylinder 80 is connected to a rotating output shaft 85 of a rotary motor 84. The rotary motor 84 is attached to and movable with the carriage 64. While the carriage limits translation of the seedling transfer mechanism 62 to a single transverse axis, the rotary motor 84 provides an additional degree of freedom the plant gripper fingers 75 can be rotated about a vertical axis. During the transfer process, in one embodiment of the present invention, rotation of the gripper fingers 75 facilitates the transfer motion.

In another embodiment of the invention, depicted in FIG. 5, a seedling transfer mechanism 62' has the extension air cylinder 80 affixed directly to the carriage 64, eliminating the rotary motor 84 and output shaft 85. All the remaining components of the mechanism 62' are identical to their counterpart components of mechanism 62. This embodiment can be accommodated by lowering the gantry 60, lengthening the extension rods 81, or adding a support bracket to the carriage 64 in order to support the seedling gripper fingers 75 in their optimum position above the seed flat plug recess PR. In this embodiment, the seedling gripper fingers are only capable of transverse movement along the single axis parallel to the guide rods 65. Thus, the transfer motion sequence of the seedling transfer mechanism 62' is modified from the motion when the rotary motor is employed.

An articulated cable support 86 can be provided to support the cables to and from the computer 100 and the gripper cylinder 78, extension cylinder 80, and rotary motor 84 (when the rotary feature of transfer mechanism 62 is employed) . The cable support is equally adapted to carry electrical wires as well as a pneumatic hose if, for instance, the extension motor is a pneumatic motor.

Referring again to FIG. 4, the seedling transfer mechanism 62 includes a liquid spray nozzle 88 attached to the gripper motor 78 by a bracket 89. (A similar nozzle can be used with the non-rotary transfer mechanism 62 ' depicted in FIG. 5, although the jet 88 is hidden from view in that figure) . A hose feeding the nozzle 88 can be carried by the cable support 86. The nozzle provides a conical spray of water to assist in releasing the seedling from the gripper fingers 75 when the seedling has been transferred above a pot flat receiver recess RR. Water sprayed directed beneath the plant also can soften the soil for ease of planting.

In addition, similar nozzles can be directed to dibble a hole in the soil to further facilitate planting the seedling. In the past, a separate machine has been provided to pre-dibble holes in the soil in each of the pot flat recesses. The present invention provides means, by way of the water nozzles, for eliminating the need to pre-dibble. Moreover, the hole dibbled by the water nozzles is always exactly located directly beneath the plant gripper fingers 75. Use of prior pre-dibbling methods permitted some dibbled holes to be offset from the location at which the seedling transfer mechanism 62 attempted to replant the seedling. In another aspect of the seedling transfer mechanism 62, a pair of limit brackets 94 can be provided. The limit brackets 94 control the outward expansion of the seedling gripper fingers 75. While the gripper cylinder 78 is preferably positively controlled so that the fingers cannot over-extend, in the event that the gripper motor 78 fails, some means are provided to keep the gripper fingers 75 from moving too far apart.

In another feature of the present invention, a flexible web 90 is mounted across the top portions 75a of the seedling gripper fingers 75. The web extends only part way around the gripper fingers to leave an open web pocket 91. The web 90 is used to gently bend the seedling stem and flower so that the seedling does not get hung up on the gripper fingers 75. In the transfer operation, the gripper fingers are preferably oriented so that the soil plug and/or seedling root ball are grabbed by the fingers slightly to one edge of the seedling gripper fingers 75 so that the plant stem and flower are disposed within the web pocket 91, and preferably contact the web 90. It has been found that the web 90 greatly improves the efficiency of the seedling transfer because the seedling does not get hung up on the gripper fingers when the fingers are inserted into the pot flat receiver recess RR to replant the seedling. The nozzle 88 can be configured to provide a conical spray so that some water is sprayed onto the web 90 to further facilitate removal of the seedling from the web pocket 91.

In the non-rotary seedling transfer mechanism 62', shown in FIG. 5, the web pocket 91 is permanently oriented to open toward the seed flat S. This fixed orientation of the web 90 requires certain accommodations in the move sequence for the non-rotary mechanism, as discussed herein. Nevertheless, the function of the web 90, to facilitate replanting of the seedling, is the same for the rotary and non-rotary versions of the seedling transfer mechanisms 62 and 62', respectively. The invention also resides in specific features for determining the filled or empty status of the seed flat plug recesses PR and the pot flat receiver recesses RR. It is understood that optimally, every plug recess PR of the seed flat will contain a seedling. However, for a variety of reasons, a seedling will not be found in a plug recess PR. In the pot flat, each recess is filled.with soil to receive a transplanted seedling. Referring to the pot flat recess as an receiver recess RR simply indicates that no seedling has been replanted into that pot flat recess. The present invention includes means for determining whether a plug recess PR contains a viable seedling and whether a transfer move to a pot flat receiver recess RR was successful.

In one embodiment of the invention, a "Machine Vision" system is used in which a camera 92 is mounted on the gantry 60 and situated above the pot flat conveyor 20. The camera, which can be outfitted with an infrared filter, takes a "picture" of the pot flat P, which is fed to the computer 100. The computer 100 employs known "frame-grabber" technology to digitize the picture and determine which of the pot flat recesses includes a replanted seedling and which do not. This information is then used to determine where the seedling transfer mechanism 62 will move to transfer a seedling from the seed flat to the next available pot flat receiver recess RR. Alternatively, the camera can be oriented above the seed flat S to determine which, if any, of the seed flat plug recesses PR does not contain a seedling. If a plug recess PR is empty, the computer 100 can sense this condition and move the seed flat and seedling transfer mechanism accordingly to the next plug recess. In one configuration, the camera 92 is mounted on the carriage 64 for the seedling transfer mechanism 62. The computer 100 can then direct the camera 92 to take a picture of both the seed flat S and the pot flat P when the mechanism 62 moves between the two flats during a transfer operation. The computer processes the information concerning the status of the recesses in the two flats to determine the next sequence of indexes of the seed and pot flats and transverse moves of the seedling transfer mechanism. In another orientation, the camera 92 is mounted on the overhead gantry 60 at a location overlooking the seed flat S. At this location, the camera 92 provides an image to be processed by the computer 100 to determine which of the plug recesses PR of the seed flat are empty or have an improperly oriented seedling. Software within the computer 100 can then direct the indexing of the seed flat and motion of the seedling transfer mechanism 62 to a proper plug recess PR. Alternatively, as shown in FIG. 5, a pair of infrared (IR) sensors 96 can replace the camera 92. The sensors 96 can be mounted by way of a bracket 97 to the non-rotary seedling transfer mechanism 62', offset to one side of the plant gripper fingers 75. Preferably, the sensors 96 are offset by about the width of a pot flat recess, preferably downstream from the pot flat recess that is immediately beneath the plant gripper fingers 75 after a seedling has been transferred. As explained more fully herein, certain moves of the apparatus 10 after the seedling has been replanted orient the IR sensors 96 directly over the pot flat recess that had most recently received a transplanted seedling. In this orientation, the sensors 96 scan the recess, preferably up to six times, to determine whether that recess is empty or has a viable seedling therein. If the pot flat recess RR is empty, the computer modifies the transfer move sequence accordingly to cause the next transfer move to again attempt to fill the same pot flat recess. The computer 100 operates as a system controller to coordinate the action of the seed flat indexing mechanism 25, pot flat indexing mechanism 45 and seedling transfer mechanism 62. More particularly, at the pot flat side of the transfer apparatus 10, the computer 100 sends signals to the pot flat gripper 29 to grip and release the pot flat, and to the pot flat pulley drive motor 34 to index the carriage 30 and edge gripping fingers 28. The computer also receives signals from the edge sensor 38. When a new pot flat is placed on the pot flat conveyor 20, the computer directs the drive motor 34 to translate the carriage 30, and consequently the edge sensor 38 mounted to the carriage, until the edge sensor detects the leading edge of the seed flat S. The computer then directs the indexing motion of the motor 34 to conduct a binary search for the proper location on the seed flat S to grip the flat. This proper location can be indicated by cutting a notch in the edge of the seed flat or by placing a sensing strip on the seed flat. When the edge sensor 38 detects this proper location, the computer actuates the gripper 29 to clamp the fingers 28 onto the edge of the seed flat. The gripper fingers 28 maintain their grip on the seed flat until all of the seed flat receiver recesses RR have been emptied.

At the pot flat side of the transfer apparatus 10, the computer 100 sends signals to the pot flat gripper 50 to grip and release the pot flat, and to the pot flat pulley drive motor 56 to index the carriage 51 and rim gripping fingers 48. The computer also receives signals from the edge sensor 59, which operates in the same manner as the seed flat edge sensor 38 to locate the proper gripping location on the pot flat P.

When the seed flat is situated at the transfer station TR (FIG. 1), the computer actuates the ejector motors or cylinders 42 that extend the ejector pins 41 of the seedling ejector 40. Once the seedling gripper fingers 75 have grabbed the seedling, the computer sends a signal to the ejector cylinders 42 to retract the ejector pins. Alternatively, the ejector pins 41 can remain in their extended position until all seedlings along a single transverse row of the seed flat S have been removed. Then, the computer 100 can direct the cylinders 42 to retract the pins to pull the pins out of the drain holes in the base of the seed flat, so that the seed flat S can be indexed to its next transverse row. However, prolonged extension of the ejector pins prolongs the exposure of the root ball of the seedlings not yet transferred. It is, therefore, believed to be preferable to extend and retract the ejector pins 41 with each seedling transfer. In this preferred embodiment, the extension air cylinder 80 and ejector air cylinders 42 are simultaneously actuated so that an ejector pin 41 pushes the subject seedling up as the seedling gripper fingers 75 are moving down around the seedling.

The computer 100 sends control signals to the rotary seedling transfer mechanism 62 or non-rotary mechanism 62', and particularly to the gripper air cylinder 78 to clamp and retract the seedling gripper fingers 75, to the extension motor 80 to extend and retract the fingers from a flat recess, and to the pulley drive motor 70 to provide for transverse motion of the transfer mechanism 62. When the rotary transfer mechanism 62 is employed, the computer also sends control signals to the rotary motor 84 to rotate the gripper fingers 75. If a nozzle 88 is utilized, signals from the computer 100 control the on-off operation of the nozzle. The computer 100 receives signals either from the camera 92 or from the IR sensors 96, depending upon which technique is used to determine the state of the seed and pot flat recesses. The computer 100 controls the sequence of movements of the seed flat, pot flat and seedling transfer mechanism in order to minimize the transfer time. The move sequences depends upon which of the rotary version of the seedling transfer mechanism 62 or the non-rotary version 62' is being used. FIG. 6 is a schematic representation of the move sequences for the non-rotary seedling transfer mechanism 62 ' , while FIG. 7 shows the move sequences when the rotary mechanism 62 is being used. In these figures, the seed flat S is represented as having only four rows and four columns, while the pot flat P is shown with only two rows and two columns, for ease of explanation. It is understood, of course, that the move sequences described below can be implemented on seed and pot flats of various dimensions. In both non-rotary and rotary move sequences, the seed and pot flats are indexed forward and backward along their respective conveyors until an appropriate recess in either flat is positioned in line with the transfer station TS. The seedling transfer mechanism, and particularly the seedling gripper fingers 75, moves over the transfer station transverse to the indexing direction of the seed and pot flats. In the preferred embodiment of both move sequences, the seedlings are removed from the seed flat S along a longitudinal column of the seed flat, and are replanted into the pot flat P along a transverse row. This move strategy minimizes the number of longitudinal indexes of the pot flat P, thereby reducing the trauma to the newly transferred and replanted seedlings already in the pot flat P.

Referring to FIG. 6 , the seed flat plug recesses PR are numbered corresponding to the sequence in which the seedlings are removed from the recesses. The pot flat receiver recesses RR are also numbered, corresponding to the order in which the recesses are filled. It is understood that each of the pot flat receiver recesses RR contain soil into which the seedling is replanted. The soil in the recesses can be pre-dibbled, or the nozzle 88 can be used to dibble a hole in the soil prior to transplanting the seedling. For purposes of explaining the move sequence, it is initially assumed that each of the plug recesses PR in the seed flat S contain a viable seedling.

In Step 1 of the move sequence, the seed flat S and pot flat P are grabbed by their respective indexing mechanisms 45 and 25 and translated longitudinally along the conveyors 13 and 20, respectively, until the first recesses PR- and RR-, are aligned with the transfer station TS. The plant gripper fingers 75 are oriented directly above the transfer station TS, with the web pocket 91 facing the seed flat S. With the seedling gripper fingers 75 retracted upward, the pulley drive motor 70 is actuated to move the seedling transfer mechanism 62* toward the seed flat S until the fingers 75 are directly above the first plug recess PR,, as shown in Step 2. The computer 100 simultaneously commands the ejector 40 to stroke upward to dislodge the seedling in recess PR, and the extension motor 78 to stroke downward to extend the fingers 75 around the seedling. As the fingers 75 extend down, the seedling enters the web pocket 91 and the web contacts the stem and flower of the seedling to bend the seedling slightly toward the seed flat S.

As the fingers 75 extend downward they penetrate the soil in the recess PR... When the fingers have been fully extended, the computer 100 directs the gripper motor 78 to gently clamp the fingers 75 about the root ball of the seedling. The extension motor 80 is then commanded to retract the fingers 75, so that the seedling is completely clear of the seed flat S. The computer 100 directs the pulley motor 70 to convey the seedling transfer mechanism 62' toward the pot flat until the fingers 75 are directly over the first pot flat receiver recess RR. , as shown in Step 3. In the preferred embodiment, the nozzle 88 is activated to dibble a hole in the soil in the recess RR, . Once the hole has been dibbled, the nozzle emits a water spray to facilitate removal of the seedling from the gripper fingers 75 and web 90. In sequence, the extension motor 80 is directed to extend the fingers until the penetrate the dibbled hole, then the fingers 75 are moved apart by the gripper motor 78 and retracted by the motor 80.

In the next step of the move sequence, the fingers 75 are moved away from the recess RR, until the web 90 is clear of the seedling. The pulley motor 56 of the pot flat indexing mechanism 45 is energized to index the pot flat P away from the fingers 75, as shown at Step 4 in FIG. 6. The pulley motor 70 of the seedling transfer mechanism 62' is activated to index the fingers into longitudinal alignment with the previously filled recess RR.. In this alignment, the IR sensors 96 are situated directly above the newly replanted seedling in recess RR,. The sensors scan the recess and transmit a signal to computer 100, which processes the signal to determine whether or not the transfer was successful. If the IR sensors 96 fail to detect a seedling in the recess, the computer 100 "remembers" the recess RR, location and redirects the seedling transfer mechanism 62' to that location during the next transfer operation. If the IR sensors detect the presence of a seedling, the computer 100 increments to the next pot flat recess RR₂ to receive the next seedling.

At some time after the fingers 75 have been transversely moved to the pot flat in Step 3, the computer commands the seed flat pulley motor 34 to move the carriage 30 and edge gripping fingers 28 in order to index the seed flat to its next position. In this next position, shown in Step 4, the second plug recess PR_? is aligned with the transfer station TS. The seed flat S is then properly positioned for the next transfer move sequence. Once the IR sensors 96 have examined the newly replanted seedling, the seedling transfer mechanism 62' is conveyed toward the seed flat and the pot flat is indexed back to the start position shown in FIG. 1. The transfer move sequence illustrated in FIG. 6 then repeats.

The computer 100 is provided with a memory to keep track of the number of longitudinal and transverse recesses in both the seed flat S and pot flat P. Software counters within the computer are incremented with each successful seedling transfer so the seedling transfer mechanism 62' can be directed to the proper plug recess PR and pot flat receiver recess RRn. When the software counters indicate the end of a column in the seed flat, the seed flat indexing mechanism 25 is directed to move the seed flat to align the first row of the flat with the transfer station TS. Likewise, when the software counters indicate that the last receiver recess in a particular pot flat row, such as recess RR-, in FIG. 6, has been filled, the computer 100 directs the pot flat indexing mechanism 45 to index the pot flat to align the next adjacent row of the flat with the transfer station TR. This cycle continues until the computer counters indicate either that the last pot flat recess, such as RR. in FIG. 6, has been filled, or that seedling from the last seed flat recess, such as PR,lb,-' ^nas been transferred.

If the camera 92 is used, instead of the IR sensors, the digitized image produced by the computer 100 can be immediately processed to ascertain which of the seed flat plug recesses PR are empty (i.e. - without a seedling) prior to initiating the move sequence. Software within the computer 100 can then compare the incremented recess counter for the seed flat with the pre-determined receiver recesses in order to direct the indexing of the seed flat accordingly. In a similar manner, the camera 92 can be used to take a "picture" of the pot flat after every transfer move sequence, that is after Step 3 in FIG. 6, in order to ascertain the identity of the next available pot flat receiver recess RR_n^ Turning now to Fig. 7, the transfer "move sequence for the rotary seedling transfer mechanism 62 (FIG. 4) is illustrated. The use of the rotary mechanism 62 permits elimination of the move steps required for the fingers 75 to clear the transplanted seedling. The first two steps of the move sequence for the rotary mechanism 62 are identical to the initial steps for the non-rotary mechanism 62'. However, in Step 3, the rotary motor 84 is actuated to rotate the fingers 75 through 180° until the web pocket 91 is facing toward the seed flat S. The seedling transfer mechanism 62 then continues its transverse motion until the fingers 75 are situated over the proper receiver recess RR,, as shown at Step 3.

In the final step of the transfer move sequence, Step 4 in FIG. 7, the fingers 75 are transversely moved directly toward the seed flat and its next plug recess P ₂ (the seed flat having been previously indexed to its next position) . During this transverse move, the rotary motor 84 is again energized to rotate the fingers through 180° until the web pocket 91 again opens toward the seed flat S. The seed flat S, pot flat P and seedling gripping fingers 75 of mechanism 62 are then oriented as shown at Step 2 in FIG. 7.

In both transfer move sequences of FIGS. 6 and 7, the net movements of the seed flat S and pot flat P are opposite. That is, the seed flat is indexed from plug recess to plug recess in one longitudinal direction on the seed flat conveyor, while the pot flat is indexed from one row to the next in the opposite longitudinal direction as the receiver recesses RR are filled. The impact of these opposite net movements is that the seedling transfer mechanisms 62 and 62' need only translate along a single axis transverse to the flat longitudinal directions. This minimizes the move distance and move time for transferring a seedling from the seed flat to the pot flat.

Another feature of the present invention is that the transfer move sequences for either mechanism 62 or 62' is dynamic. The computer 100 receives information concerning the plug recesses PRm in the seed flat and receiver recesses RRn in the pot flat that is used to determine when and where the flats must be indexed and the seedling transfer mechanism moved to find the next seedling and move it to the next available pot flat recess. This feature represents a significant improvement over prior art devices that are unable to avoid propagating errors in the seed flat over to the pot flat, or are unable to determine when a seedling has been lost in transit and not replanted in the pot flat. The sensors 96 or camera 92 provide means for detecting the condition of the flat recesses, which condition information is processed by the computer 100 to determine the optimum move strategy in milliseconds. Thus, the computer controlled seedling transfer apparatus 10 of the present invention optimizes transfer accuracy and seedling transfer rates for a significantly more efficient operation than provided by prior art devices.

In an alternative embodiment of the present invention, seedlings from two seed flats can be transferred into a single pot flat. More specifically, a transfer apparatus 110 shown in FIG. 8 includes two seed beds 113, each comprising a frame assembly 114 supporting a plate 115. A seed flat, designated "S" as in FIG. 1, is supported on the plate 115 of each seed bed 113.

Situated between the two seed beds 113 is a pot bed 120. The pot bed 120 is formed by a frame assembly 121 which supports a plate 122. A pot flat, designated as "P" as in FIG. 1, is supported by the plate 122. The relative heights between the two seed beds 113 and the pot bed 120 can be adjusted. However, the pot bed 120 is preferably situated below the level of the seed beds to aid in the planting operation and to accommodate a dibbler assembly 150 (discussed in more detail herein) . The seed bed 113 and pot bed 120 of the transfer apparatus 110 is supported on transverse frame members 111. These frame members can be connected to the triangular support frame 11 shown in FIG. 1. It is understood that this transfer apparatus 110 is intended as a substitute for the seed conveyor 13, pot conveyor 20 and moving means 25 and 45 of the previous embodiment shown in FIG. 1.

Referring still to FIG. 8, the transfer apparatus 110 includes seed flat moving means 125 which is used to index the seed flats S in accordance with or similar to the procedure described above (with reference to FIGS. 6 and 7). The seed flat moving means 125 includes a motor 126 which is preferably a stepper motor or a digital motor, or other motor capable of incremental movement. The motor 126 rotates a keyed drive shaft 127 which extends between both seed beds 113. A pair of pusher drums 128 is mounted on the drive shaft 127, with one drum each being situated in the frame 114 of each seed bed 113. The drums 128 are provided to help push seed flats from an input conveyor (not shown) onto the seed beds 113. It is understood that the transfer apparatus 110 can mate with a gravity feed conveyor so that a series of seed flats S can be transferred onto each of the seed beds 113. Likewise, a third conveyor can be provided to transfer empty pot flats P to the pot bed 120.

The seed flat moving means 125 includes a number of sprockets 130 mounted on the drive shaft 127. In the preferred embodiment, two sprockets are provided for each seed bed and are situated at the lateral sides of the frame 114 of each bed 113. A rear axle 131 is also provided at the opposite end of each of the seed beds 113, upon which additional pairs of sprockets 130 are mounted. A drive chain 132 is then engaged across the sprockets 130 at opposite ends of the seed bed and at each side of the seed beds 113. A number of cleats 134 are engaged between the drive chains 132 at either side of the seed beds 113. The cleats 134 are preferably uniformly situated around the circumference of the drive chain 132 at distances sufficiently large to accommodate a seed flat S between successive cleats. The cleats have a thickness great enough to exert a pushing force on a corresponding seed flat. Since the seed flat moving means 125 is used to move the seed flats in finite increments, it is important-that a seed flat S fit snugly between successive cleats 134. In addition, the cleats 134 include an upward projecting rim 134a which is used to grap underneath the rim of a seed flat to help pull the seed flat onto the seed flat bed.

In one specific alternative version, only two cleats 134 are provided for each seed bed 113. This cleat arrangement is acceptable since the seed flats can be discharged from the seed beds 113 when they are emptied. Alternatively, a number of cleats 134 can be evenly spaced around the entire circumference of the drive chain 132 so that the drive chain can be continuously rotated to provide cleats for successive seed flats entering the seed bed 113. In either version, the chain and cleat arrangement eliminates the pneumatic gripper assembly of the prior embodiment (such as gripper 27) . However, edge sensors, such as sensors 59, may still be employed to determine when a flat is at an appropriate starting location on the seed flat beds 113.

Also included in the transfer apparatus 110 is a pot flat moving means 140 which includes a drive motor 141, which may also be a digital or stepper motor. The pot flat moving means 140 also includes a pusher drum 143 driven by the motor

141, as well as sprockets 145 engaged to the drive motor axle

142. As with the seed flat moving means 125, the pot flat moving means 140 includes four sprockets 145, two at each end of the pot bed 120, and two at each side of the bed. Likewise, two drive chains 147 are engaged between the sprockets at either side of the pot bed 120. A number of cleats 149 are affixed to the drive chain 147. The cleats 149 are spaced apart to accommodate a pot flat P therebetween. Since the pot flat P will normally move in only one direction (that is toward the discharge end of the pot bed 120), a tight fit between successive cleats 149 is not required. Preferably, the drive chain 147 includes a number of cleats 149 uniformly spaced apart around the circumference of the chain so that the drive motor 141 can continuously rotate the chain in one direction, discharging filled pot flats and receiving empty pot flats at the input end of the pot bed 120. The pot bed 120 also includes a dibbler assembly 150 mounted near the input end of the pot bed. The dibbler assembly 150 includes a mounting bracket 151 affixed to the pot bed frame 121. A number of spray nozzles 152 are mounted beneath the bracket so that the nozzles direct a jet of water downward into soil held within the pot flat P. The spray nozzles 152 can be appropriately connected to a source of fluid (not shown), such as water, to perform the dibbling operation. The dibbler assembly 150 is preferably situated remote from the transfer location for the transfer apparatus 110. Likewise, the dibbler assembly 150 must be located far enough away from the input end of the pot bed 120 to perform the dibbling operation at the endmost pot flat locations.

In the sequence of operation of the transfer apparatus 110, new pot flats with soil-filled recesses are pushed by pusher drum 143 onto the plate 122 and contacted by a cleat 149. The cleat pushes the pot flat P along the plate until the first transverse row of the pot flat is beneath the dibbler assembly 150. The dibbling operation continues at each successive row of the pot flat as the cleat incrementally pushes the flat. After the last row has been dibbled, the pot flat is advanced to the transfer location at the end of the pot flat bed 120.

The transfer apparatus 110 also includes a pair of ejector means 155, one each of which is situated under each of the seed beds 113 to eject the seedlings from the seed flats S. Each ejector means 155 includes a motor 156 affixed to the corresponding seed bed frame 114 by way of a motor mount 157, as shown in FIG. 8. Referring now to FIG. 9, the remaining details of each ejector means 155 are shown. In particular, the motor 156 includes a drive shaft 158 which extends underneath the seed bed 113. The drive shaft 158 includes a lead screw 159. Mounting blocks 160 provide a bearing support for the motor drive shaft/lead screw 158/159, as well as means for mounting the ejector means underneath the seed bed 113. A gap is provided in the seed bed plate 115 so the ejector means can have access to the drain openings in the base of the seed flat S. The ejector means 155 further includes an ejector carrier 162 which is supported by a pair of guide shafts 163 mounted between the blocks 160. The ejector carrier 162 includes a driven nut 164 affixed thereto. The lead screw 159 extends through the driven nut 164 between the mounting blocks 160. Rotation of the motor, and consequently the lead screw 159, causes the nut 164, and ejector carrier 162 connected thereto, to move laterally across the width of the seed bed 113. Ejector carrier 162 supports an ejector assembly 165, which includes a solenoid 166 that reciprocatably activates an ejector pin 167. A needle 168 projects from the pin 167. When the pin 167 pushes a seedling, the needle 168 extends into the root ball to help stabilize the seedling as it is supported by the ejector pin 167. In one specific embodiment, the needle is about 20πιm long.

The ejector means 155 differs in operation from the ejector 40 of the previous embodiments. As may be recalled, the ejector 40 includes a number of ejector pins which are simultaneously actuated to push the seedlings up from every location in a row of the seed flat S. However, with the ejector means 155 of this alternative embodiment, only a single seedling is pushed up or ejected from the seed flat at any given time. The stroke of the solenoid 166 allows the ejector pin 167 to completely displace the root ball of the seedling from the seed flat S as it is being gripped by the gripper fingers. Consequently, given that the seedling is completely displaced from the seed flat, it is not prudent to eject all seedlings in a row at the same time, but rather to only eject the seedling being transferred to the pot flat. With the ejector means 155 of this embodiment then, the motor 156 must be capable of incremental and reversible motion to move the ejector means 155 tranversely to the appropriate seed flat row location. In the specific embodiment, the ejector pin 167 can be moved only transversely across the seed flat bed. Thus, the sequence of transfer moves require positioning the row of the particular seedling to be transferred over the ejector means location. The ejector means motor 1546 can then index the ejector pin 167 to the proper column of the seed flat S.

The transfer apparatus 110 shown in FIG. 8, along with the ejector means 155 shown in FIG. 9, provide means for transferring seedlings from two seed flats S to a single pot flat P. Thus, the speed of transfer of seedlings can be nearly doubled by the addition of a second seedling gripper assembly, such as seedling gripper assembly 62 shown in FIGS. 1 and 4. The assembly 110 can also include a camera, such as camera 92, situated above the pot flat bed 120. As discussed 5 above, this camera takes a picture of the pot flat P in order to determine which of the pot flat recesses includes a replanted seedling, or to determine whether a seedling transfer operation was successful. The camera can also be used to take a picture of the seed flats to determine whether

10 the plug recesses contain a seedling prior to attempting to execute a transfer operation.

With the transfer apparatus 110 of this embodiment, it is contemplated that each of the seed beds 113 is situated at the end of a gravity feed conveyor. Similarly, the pot bed

15 120 is also situated at the end of the gravity feed conveyor. Seed flats carrying seedlings in its recesses are conveyed from the conveyors (not shown) onto the seed beds 113, as are empty pot flats P conveyed onto the pot bed 120. This embodiment further contemplates that the pot flats will

20 be discharged onto a second gravity feed conveyor once all of the recesses of the pot flat have been filled. The seed beds 113 need not mate with discharge conveyors, since the empty seed flats S can be discarded by simply dropping onto the floor.

25 It is further understood that the transfer apparatus 110 of this embodiment can be integrated with a computer system as described above, which includes a computer 100 that operates as a system controller to coordinate the action of the seed flat moving means 125, the pot flat moving means

30 140, the dibbler assembly 150, the ejector means 155 and the seedling gripper assembly. The sequence of operation of the transfer apparatus 110 of this embodiment is not modified significantly from the sequence of steps described in connection with the transfer apparatus 10 of the previous

35 embodiment. Seed flats S provided from the input conveyors (not shown) are pushed onto the seed beds 113 by way of the rollers 128. Likewise, empty pot flats are also pushed onto the pot bed 120 by the roller 143. The computer, such as computer 100 (see FIG. 1), can direct the motors 126 and 141 to rotate their corresponding rollers 128 and 143 until the flats are situated on their respective beds. The flats are then engaged by the corresponding cleats, either cleats 134 for the seed flats or cleats 149 for the pot flat. As depicted in the right-most seed bed 113 in FIG. 8, a seed flats S is advanced to the end of the bed 113. As shown in the left-most seed bed, a second seed flat S can also be pushed onto the seed bed and situated between cleats. It should be understood that the computer will need to advance more pot flats P onto the pot bed 120 than seed flats onto the seed beds 113 because the pot flats P typically have considerably fewer recesses for receiving transferred seedlings than the number of recesses on any given seed flat. Thus, the computer will direct operation of the seed flat rollers 143 periodically to advance additional pot flats as each flat is filled with seedlings from the several seed flats S on both seed beds 113.

Both the seed flats S and the pot flats P are advanced to the transfer location at the ends of their respective beds. Edge sensors can be provided, such as edge sensor 38 discussed above, to determine when the corresponding flats are in their proper position. Once the computer determines that the seed and pot flats are in position, the seedling transfer steps are commenced. The sequence in which the seedlings from the seed flats are removed can be the same as shown in steps 1-4 in FIG. 6. In other words, the computer can direct the seed flat moving means 125 to sequentially advance the seed flat along the bed 113 to remove all the seedlings in a single column of the seed flat S. The seedlings can then be secured by a gripper assembly and conveyed to recesses in the pot flat P in the same sequence shown in FIG . 6.

Since both seed flat moving means 130 on the two beds 112 are connected to a single motor 126 by way of the common keyed shaft 127, move sequences ^"for seed flats on both beds can be identical. More particularly, as one flat is advanced to another row, the other flat must also be advanced the same distance. However, although the seed flats themselves move in unison, the plant grippers serving the two seed flat beds need not move together, although typically the left and right grippers would move on mirror image paths unless a bad transfer has occurred.

The transfer apparatus 110 of the present embodiment, can contemplate a few modifications to this transfer sequence. In particular, the presence of a single ejector pin (pin 167 in ejector 165) means that the computer must control the motor 156 of the ejector means 155 to move the ejector to the appropriate column as the seedling gripper assembly moves to the particular seed flat location. In addition, as described above, the ejector means 155 provides means for completely pushing the seedling out of the seed flat S. Thus, the computer need not direct the seedling gripper to advance into the seed flat itself as previously described. Instead, the gripper fingers need only advance to the surface of the soil in the seed flat S until the seedling is pushed between the fingers. At that time, the computer can direct the seedling gripper fingers to grab the seedling and commence its move sequence.

A second modification of the prior sequence is contemplated by the presence of the two seed beds 113 which carry at least two seed flats S. As discussed above, two seedling gripper assemblies can be provided which are independently controlled. Both gripper assemblies feed seedlings into a single pot flat P. Thus, the sequence of moves of the separate gripper assemblies must be coordinated so that they do not conflict with each other. In addition, it is preferable that neither of the seedling gripper assemblies advance over a location in the pot flat P that has already received a seedling, thereby eliminating the risk of damage to a transplanted seedling. Thus, referring to FIG. 6, it is seen that one seedling gripper assembly can be used to fill the pot flat recesses 2 and 4 while the opposite seedling gripper assembly can be used to fill pot flat recesses 1 and 3. When properly controlled by the computer 100, these transfer operations can occur substantially simultaneously, since the path of the seedling gripper assemblies will not interfere with each other. Alternatively, the seedling transfers can occur sequentially between the two seed beds 113.

As described more completely above, the seedlings are transferred from columns of the seed flat S into transverse rows of the pot flat P. Thus, the computer need only direct movement of the pot flat P once an entire row is filled. Typically, a single row of a pot flat will include an even number of recesses so that the same number of transfers can occur between the two seed flats S resting on the two seed beds 113. However, it should be borne in mind that the camera described above generates a picture of the pot flat to determine whether each of the recesses in a given row has been filled. If not, a separate single transfer move may be required from either one of the seed flats S to fill the empty pot flat recess. The computer maintains a record concerning which seed flat recess has had its seedling removed therefrom so that the seedling grippers do not advance to a now empty seed flat recess. As indicated above, FIG. 6 is a schematic representation of the move sequences for a nonrotating seedling transfer mechanism, such as mechanism 62' (see FIG. 4). This particular transfer mechanism 62' includes a web 90 across a portion of the gripping fingers 75 which requires additional moves in the sequence. An alternative embodiment of the seedling gripper assembly is shown in FIG. 10. In particular, this gripper assembly includes plant gripper fingers 172 which do not utilize a web between the fingers. The gripper fingers are connected to a motor 173 which move the fingers together and apart. The motor 173 is supported by a base 174 which is reciprocatably mounted to a carriage 175. An extension motor 176 comprises an air cylinder which is used to advance or retract the carriage 175 and consequently the gripper fingers 172. Shaft 177 is provided to support the motor 176 over the length of its stroke. A number of water jets 178 can be mounted by brackets 179 to the base 174. These water jets operate in a manner similar to the jet 88 described in connection with FIG. 4 to assist in the transplanting step of the operation. The carriage 175 includes a drive belt attachment plate 180 which can be used to connect the seedling gripper assembly 170 to a drive belt, such as drive belt 67, shown in FIGS. 1 and 4.

In a further modification of the seedling gripper assembly, the carriage includes a guide roller assembly 183 which includes a number of rollers having rail engagement grooves 184. These rollers are adapted to engage a gripper rail 185 which supports the seedling gripper assembly 175. This support rail 185 can be used in place of the guide rods 65 as supporting the seedling gripper assembly 62 shown in FIG. 1. In one version, a single support rail 185 spans between the side supporting members of the frame 11. Two seedling gripper assemblies can be supported by this rail 185. It is understood that each of the seedling gripper assemblies 170 mounted on the rail 185 will be driven by a separate belt, such as belt 67, and motor, such as motor 70 shown in FIG. 1. The belt and motor driving a corresponding seedling gripper assembly 170 can be mounted on opposite sides or on one side of the support rail 185, provided the belts and motors do not interfere with one another. It is understood, of course, that this seedling gripper assembly 170 can be used in place of the seedling gripper assembly 62 described above. Moreover, this gripper assembly can be used with either transfer apparatus 10 or apparatus 110. The gripper finger motor 173 and extension motor 176 can be connected to the controlling computer 100 in a manner similar to that discussed above. The control of these two motors 173 and 176 can occur in the same manner as described with respect to the transfer apparatus 10 of the previous embodiment. However, as also explained, the fingers 172 need not be extended into soil in the seed flat S when the ejector means 155 is implemented.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. For example, while the preferred embodiment of the invention described includes free-wheeling conveyors 13 and 20 and flat indexing mechanisms 25 and 45, the indexing mechanisms can be replaced by indexing conveyors using driven rollers or a driven belt. However, the indexing conveyors must be capable of precise high-speed movements in order to properly move the seed and pot flats.

It is also understood that while the present invention is described for use as a seedling transfer apparatus, the invention may be equally suited for other applications that require piece-wise transfers at high speed and high accuracy.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for sequentially transferring plant seedlings from seed flats, each having a number of plug recesses initially containing a number of plant seedlings therein, to pot flats, each having a number of receiver recesses to be filled with seedlings, the apparatus comprising: means for supporting the seed flats and the pot flats to permit movement of the flats; transfer means for transferring a seedling from a plug recess in a seed flat to a receiver recess in a pot flat, said transfer means including; plant gripper means for releasably gripping the seedling to remove the seedling from a plug recess of a seed flat and to release the seedling in a receiver recess of a pot flat; and means for moving the plant gripper means between a seed flat and a pot flat along a transfer axis while the plant gripper means is gripping the seedling; and flat moving means for moving a seed flat and a pot flat so that a next sequential plug recess in the seed flat is oriented along said transfer axis when the plant gripper means is at the seed flat, and a next sequential receiver recess in the pot flat is oriented along said transfer axis when the plant gripper means is at the pot flat.

2. The apparatus for sequentially transferring plant seedlings of claim 1, wherein: said flat moving means includes: first means for moving the seed flat along a first axis; and second means for moving the pot flat along a second axis; said first and second axes are parallel and said transfer axis intersects said first and second axes.

3. The apparatus for sequentially transferring plant seedlings of claim 2, wherein said transfer axis is fixed relative to said first and second axes.

4. The apparatus for sequentially transferring plant seedlings of claim 1, further comprising: pot flat sensing means for sensing whether a seedling has been released into said next receiver recess and for sending a first signal to said flat moving means in response thereto, wherein said flat moving means is responsive to said first signal to move the pot flat so that a new receiver recess is oriented along said transfer axis when said first signal is received from said pot flat sensing means.

5. The apparatus for sequentially transferring plant seedlings of claim 1, further comprising: seed flat sensing means for sensing whether a plug recess in the seed flat contains a seedling and for sending a second signal to said flat moving means in response thereto, wherein said flat moving- means is responsive to said second signal to move the seed flat so that a new plug recess is oriented along said transfer axis when said second signal is received from said seed flat sensing means.

6. The apparatus for sequentially transferring plant seedlings of claim 1, wherein said plant gripper means includes: a pair of resilient fingers; means for moving said pair of fingers together and apart to grip and release a seedling; and a flexible web affixed between said resilient fingers defining a web pocket between said fingers and said web to contain a portion of the seedling therein.

7. The apparatus for sequentially transferring plant seedlings of claim 6, wherein said plant gripper means further includes means for rotating said pair of fingers to change the orientation of said web pocket.

8. Tlie apparatus for sequentially transferring plant seedlings of claim 1, wherein said transfer means includes a liquid spray nozzle.

9. The apparatus for sequentially transferring plant seedlings of claim 8, in which the receiver recesses in the plug flat include soil within which the seedlings are to be replanted, wherein: said nozzle is adapted to provide a jet spray at said next receiver recess when the plant gripper means is at the pot flat, said jet spray being sufficiently concentrated to dibble a hole in the soil contained within said next receiver recess for receipt of the seedling therein.

10. The apparatus for sequentially transferring plant seedlings of claim 1 further comprising dibbling means for simultaneously dibbling each receiver recess in a row of a ot flat.

11. The apparatus for sequentially transferring plant seedlings of claim 10, wherein said dibbling means includes a number of liquid jet nozzles mounted over said means for supporting the pot flat remote from said transfer axis.

12. The apparatus for sequentially transferring plant seedlings of claim 1, further comprising ejector means for ejecting a seedling from a plug recess of a seed flat, including: an ejector pin adapted to extend through a drain hole in the plug recess of the seed flat for pushing the root ball of the seedling from the seed flat recess; ejection means for extending and retracting said ejector pin, said ejection means being mounted on a carriage; and means for translating said carriage to align said ejector pin with another drain hole.

13. The apparatus for sequentially transferring plant seedlings of claim 12, wherein said ejector pin includes a needle extending therefrom for projecting into the root ball of the seedling when said pin pushes the seedling from the seed flat.

14. The apparatus for sequentially transferring plant seedlings of claim 1, wherein: said means for supporting a seed flat and a pot flat includes; a pot flat bed for supporting a pot flat; and a pair of seed flat beds straddling said pot flat bed for supporting a plurality of seed flats; and said transfer means includes means for alternatively transferring a seedling from a seed flat on one or the other of said pair of seed flat beds.

15. The apparatus for sequentially transferring plant seedlings of claim 14, wherein said transfer means includes: first and second plant gripper means for releasably gripping a seedling; and first and second means for moving a corresponding one of said first and second plant gripper means between a corresponding one of said pair of seed flats and a pot flat on said pot flat bed.

16. The apparatus for sequentially transferring plant seedlings of claim 14 further comprising dibbling means for εimultaneously dibbling each receiver recess in a row of a pot flat.

17. The apparatus for sequentially transferring plant seedlings of claim 16, wherein said dibbling means includes a number of liquid jet nozzles mounted over said pot flat bed remote from said transfer axis.

18. The apparatus for sequentially transferring plant seedlings of claim 14, further comprising ejector means for ejecting a seedling from a plug recess of a seed flat, including: an ejector pin adapted to extend through a drain hole in the plug recess of the seed flat for pushing the root ball of the seedling from the seed flat recess; ejection means for extending and retracting said ejector pin, said ejection means being mounted on a carriage; and means for translating said carriage to align said ejector pin with another drain hole.

19. The apparatus for sequentially transferring plant seedlings of claim 18, wherein said ejector pin includes a needle extending therefrom for projecting into the root ball of the seedling when said pin pushes the seedling from the seed flat.

20. The apparatus for sequentially transferring plant seedlings of claim 18, wherein said means for translating said carriage includes: a threaded nut mounted on said carriage; a lead screw extending through and threadedly engaging said nut; and a motor reversibly rotatably driving said lead screw.

21. An apparatus for sequentially transferring objects from a first flat having a number of positions initially containing a number of objects, to a second flat having a number of receiver positions for receiving objects, the apparatus comprising: first means for moving the first flat along a first axis; second means for moving the second flat along a second axis; gripper means for releasably gripping the object to remove the object from a position on the first flat and to release the object at a receiver position on the second flat; and gripper moving means for moving the gripper means between the first flat and the second flat along a transfer axis while the gripper means is gripping the object; and computer controller means for controlling the operation of said first means, said second means, said gripper means and said gripper moving means so that the gripper means removes objects sequentially from positions on the first flat and releases the objects onto sequential receiver positions on the second flat, said computer controller includes means implementing an algorithm to minimize the travel distance of the gripper moving means between sequential positions on the first and second flats.

22. The apparatus for sequentially transferring objects of claim 21, wherein said computer controller means includes means for moving the first flat and the second flat so that a next sequential position on the first flat is oriented along said transfer axis when the gripper means is at the first flat, and a next sequential receiver position on the second flat is oriented along said transfer axis when the gripper means is at the second flat.

23. The apparatus for sequentially transferring objects of claim 21, wherein said computer controller means includes means for sensing whether an object is located on the next sequential position of the first flat and for moving the first flat so that said next sequential position is oriented along said transfer axis only when an object is sensed.

24. The apparatus for sequentially transferring objects of claim 21, wherein said computer controller means includes means for sensing whether an object has been released on the next sequential receiver position of the second flat and for moving the second flat so that a new sequential receiver position is oriented along said transfer axis only when an object is sensed.

25. The apparatus for sequentially transferring objects of claim 21, wherein said computer controller means includes: means for sensing whether an object is located on each of the number of positions on the first flat; and means for implementing a second algorithm to control the movement of the gripper means to only those locations on the first flat having an object located thereon.

26. The apparatus for sequentially transferring objects of claim 21, adapted to further transfer objects from a third flat to the second flat, the apparatus further comprising: third means for moving the third flat along a third axis, wherein each of said axes is parallel and said first and third axes straddle said second axis; second distinct gripper means for releasably gripping an object to remove the object from a position on the third flat and to release the object at a receiver position on the second flat; and second gripper moving means for moving the gripper means between the third flat and the second flat along a second transfer axis while the second gripper means is gripping the object; and wherein said computer controller means further controls the operation of said third means for moving, said second gripper means and said second gripper moving means so that the second gripper means removes objects sequentially from positions on the third flat and releases the objects onto sequential receiver positions on the second flat, said computer controller means includes means implementing an algorithm to minimize the travel distance of the second gripper moving means between sequential positions on the third and second flats.

27. The apparatus for sequentially transferring objects of claim 26, wherein said computer controller means operates to control said first and third gripper means and gripper moving means to simultaneously transfer two objects into different receiver positions of the second flat.

AMENDED CLAIMS

[received by the International Bureau on 14 December 1992 (14.12.92); original claims 1,6,8 and 21 amended; new claims 28-33 added; other claims unchanged (12 pages)]

1. An apparatus for sequentially transferring plant seedlings from seed flats, each having a number of plug recesses initially containing a number of plant seedlings therein, to pot flats, each having a number of receiver recesses to be filled with seedlings, the apparatus comprising: means for supporting the seed flats and the pot flats to permit movement of the flats; transfer means for transferring a seedling from a plug recess in a seed flat located along a first directional axis to a receiver recess in a pot flat located along a second directional axis, said second directional axis oriented perpendicular to said first directional axis, said transfer means including; plant gripper means for releasably gripping the seedling to remove the seedling from a plug recess of a seed flat and to release the seedling in a receiver - recess of a pot flat; and means for moving the plant gripper means between a seed flat and a pot flat along a transfer axis while the plant gripper means is gripping the seedling; and flat moving means for moving a seed flat and a pot flat so that a next sequential plug recess in the seed flat is oriented along said transfer axis when the plant gripper means is at the seed flat, and a next sequential receiver recess in the pot flat is oriented along said transfer axis when the plant gripper means is at the pot flat.

5. The apparatus for sequentially transferring plant seedlings of claim 1, further comprising: seed flat sensing means for sensing whether a plug recess in the seed flat contains a seedling and for sending a second signal to said flat moving means in response thereto, wherein said flat moving means is responsive to said second signal to move the seed flat so that a new plug recess is oriented along said transfer axis when said second signal is received from said seed flat sensing means. 6. An apparatus for sequentially transferring plant seedlings from seed flats, each having a number of plug recesses initially containing a number of plant seedlings therein, to pot flats, each having a number of receiver recesses to be filled with seedlings, the apparatus comprising: means for supporting the seed flats and the pot flats to permit movement of the flats; transfer means for transferring a seedling from a plug recess in a seed flat to a receiver recess in a pot flat, said transfer means including; plant gripper means for releasably gripping the seedling to remove the seedling from a plug recess of a seed flat and to release the seedling in a receiver recess of a pot flat wherein said plant gripper means includes: a pair of resilient fingers; means for moving said pair of fingers together and apart to grip and release a seedling; and a flexible web affixed between said resilient fingers defining a web pocket between said fingers and • said web to contain a portion of the seedling therein; and means for moving the plant gripper means between a seed flat and a pot flat along a transfer axis while the plant gripper means is gripping the seedling; and flat moving means for moving a seed flat and a pot flat so that a next sequential plug recess in the seed flat is oriented along said transfer axis when the plant gripper means is at the seed flat, and a next sequential receiver recess in the pot flat is oriented along said transfer axis when the plant gripper means is at the pot' flat.

7. The apparatus for sequentially transferring plant seedling's of claim 6, wherein said plant gripper means further includes means for rotating said pair of fingers to change the orientation of said web pocket.

8. An apparatus for sequentially transferring plant seedlings from seed flats, each having a number of plug recesses initially containing a number of plant seedlings therein, to pot flats, each having a number of receiver recesses to be filled with seedlings, the apparatus comprising: means for supporting the seed flats and the pot flats to permit movement of the flats; transfer means for transferring a seedling from a plug recess in a seed flat to a receiver recess in a pot flat, said transfer means including; plant gripper means for releasably gripping the seedling to remove the seedling from a plug recess of a seed flat and to release the seedling in a receiver recess of a pot flat; a liquid spray nozzle attached to the plant gripper means and directed to emit a liquid spray beneath the plant gripper means; and means for moving the plant gripper means between a seed flat and a pot flat along a transfer axis while the plant gripper means is gripping the seedling; and flat moving means for moving a seed flat and a pot flat so that a next sequential plug recess in the seed flat is oriented along said transfer axis when the plant gripper means is at the seed flat, and a next sequential receiver recess in the pot flat is oriented along said transfer axis when the plant gripper means is at the pot flat.

10. The apparatus for sequentially transferring plant seedlings of claim 1 further comprising dibbling means for simultaneously dibbling each receiver recess in a row of a pot flat.

16. The apparatus for sequentially transferring plant seedlings of claim 14 further comprising dibbling means for simultaneously dibbling each receiver recess in a row of a pot flat.

19. The apparatus for sequentially transferring plant seedlings of claim 18, wherein said ejector pin includes a needle extending therefrom for projecting into the root ball of the seedling when said pin pushes the seedling from the seed flat. 20. The apparatus for sequentially transferring plant seedlings of claim 18, wherein said means for translating said carriage includes: a threaded nut mounted on said carriage; a lead screw extending through and threadedly engaging said nut; and a motor reversibly rotatably driving said lead screw.

21. An apparatus for sequentially transferring objects from a first flat having a number of positions initially containing a number of objects, to a second flat having a number of receiver positions for receiving objects, the apparatus comprising: first means for moving the first flat along a first axis; second means for moving the second flat along a second axis; gripper means for releasably gripping the object to remove the object from a position on the first flat located along a first directional axis and to release the object at a receiver position on the second flat located along a second directional axis, said second directional axis oriented perpendicular to said first axis; gripper moving means for moving the gripper means between the first flat and the second flat along a transfer axis while the gripper means is gripping the object; and computer controller means for controlling the operation of said first means, said second means, said gripper means and said gripper moving means so that the gripper means removes objects sequentially from positions on the first flat and releases the objects onto sequential receiver positions on the second flat, said computer controller means includes means implementing an algorithm to minimize the travel distance of the gripper moving means between sequential positions on the first and second flats.

26. The apparatus for sequentially transferring objects of claim 21, adapted to further transfer objects from a third flat to the second flat, the apparatus further comprising: third means for moving the third flat along a third axis, wherein each of said axes is parallel and said first and third axes straddle said second axis; second distinct gripper means for releasably gripping an object to remove the object from a position on the third flat and to release the object at a receiver position on the second flat; and second gripper moving means for moving the gripper means between the third flat and the second flat along a second transfer axis while the second gripper means is gripping the object; and wherein said computer controller means further controls the operation of said third means for_^moving, said second gripper means and said second gripper moving means so that the second gripper means removes objects sequentially from positions on the third flat and releases the objects onto sequential receiver positions on the second flat, said computer controller means includes means implementing an algorithm to minimize the travel distance of the second gripper moving means between sequential positions on the third and second flats. 27. The apparatus for sequentially transferring objects of claim 26, wherein said computer controller means operates to control said first and third gripper means and gripper moving means to simultaneously transfer two objects into differen receiver positions of the second flat.

28. The apparatus for sequentially transferring plant seedlings of claim 2, wherein said first means for moving is configured to move said seed flat in opposite directions along said first axis and wherein said second means for moving is configured to move said pot flat in opposite directions along said second axis.

29. The apparatus for sequentially transferring plant seedlings of claim 22, wherein said first means for moving is configured to move said seed flat in opposite directions along said first axis and wherein said second means for moving is configured to move said pot flat in opposite directions along said second axis.

30. The apparatus for sequentially transferring plant seedlings of claim 4, wherein said pot flat sensing means includes a camera for producing an image of said pot flat and computer means for interpreting said image to determine whether a seedling has been released into a pot flat recess.

31. The apparatus for sequentially transferring plant seedlings of claim 5, wherein said seed flat sensing means includes a camera for producing an image of said seed flat and computer means for interpreting said image to determine whether a seed flat recess contains a seedling.

32. The apparatus for sequentially transferring plant seedlings of claim 25 wherein said means for sensing includes a means for producing a digital image of those locations on the first flat having an object located thereon.

33. The apparatus for sequentially transferring plant seedlings of claim 24 wherein said means for sensing includes a means for producing a digital image for determining whether an object has been released on the next sequential receiver position of the second flat.