US20120186288A1

US20120186288A1 - Ice-harvest drive mechanism with dual position bail arm

Info

Publication number: US20120186288A1
Application number: US13/288,443
Authority: US
Inventors: Kenyon A. Hapke
Original assignee: Illinois Tool Works Inc
Current assignee: Illinois Tool Works Inc
Priority date: 2011-01-21
Filing date: 2011-11-03
Publication date: 2012-07-26

Abstract

An ice-maker drive mechanism presents a housing having a frontward extending drive for an ice-harvester mechanism and left and right bail arm drive hubs. A bail arm that may drop into an ice bin collecting ice from the ice-maker to sense a height of ice cubes in a the ice bin may be attached to either of the left and right bail arm drive hubs providing a versatile ice-making mechanism that may be used in a variety of refrigerator designs.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application 61/435,008 filed Jan. 21, 2011, hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to ice-making machines for home refrigerators and the like and specifically to an ice-harvest drive used with ice making machines and adapted to be mounted in different orientations and positions within the refrigerator.

BACKGROUND OF THE INVENTION

Household refrigerators commonly include automatic ice-makers located in the freezer compartment. A typical ice-maker provides an ice cube mold positioned to receive water from an electrically operated valve that may open for a predetermined time to fill the mold. The water is allowed to cool in the mold until a temperature sensor attached to the mold detects a predetermined low-temperature point where ice formation is ensured. At this point, the ice is harvested from the mold by an ice-harvest mechanism operated by a drive. The ice-harvesting mechanism may distort the ice mold to remove the “cubes” or may use mechanical ejectors passing into the ice mold to sweep the cubes from the ice mold.
An ice sensor may be provided to determine when the ice-receiving bin is full. One sensor design incorporated into the ice-harvest drive periodically lowers a bail arm into the ice bin after each harvesting, to gauge the amount of ice in the bin. If the bail arm's descent is limited by an ice pile of a predetermined height, harvesting is suspended.
The location of the ice-maker and the accumulating bin may be varied substantially among different models of refrigerators depending, for example, on whether the ice-maker is located in an upper freezer compartment where it may be placed in an elevated position to the rear of the compartment or in a drawer compartment at the lower portion of the refrigerator where it may be moved forward, for example to a side of the compartment, depending on options such as whether there is automatic delivery of ice through the door. The different design constraints on these ice-makers require multiple versions of the ice-harvest drive increasing their costs and complexity.

SUMMARY OF THE INVENTION

The present invention provides an improved ice-harvest drive that may be flexibly mounted in multiple locations for use among different refrigerator models. A low profile gear system may be supported by a rear housing wall in cantilevered fashion and provides a bail arm that may be positioned on either side of a housing as may be required for these different mounting locations.
Specifically, the present invention provides an ice-harvest drive having a housing with a front wall adapted to be positioned adjacent to an ice mold for molding ice cubes, and having right and left sidewalls flanking the front wall. A first rotatable shaft is exposed through the front wall to communicate with the ice mold and a second rotatable shaft extends between the right and left side walls and having first and second ends exposed through each. A reciprocating mechanism communicates with the first rotational shaft to provide reciprocation of the second rotatable shaft with rotation of the first rotatable shaft. A bail arm is attachable to one of the first and second ends and an electric motor held by the housing drives the first rotatable shaft.
It is thus a feature of at least one embodiment of the invention to provide a flexible mechanism that may be used for a variety of different refrigerator configurations.
The reciprocating mechanism may be a cam attached to rotate with the first rotatable shaft and a cam follower attached to the second rotatable shaft and communicating with the cam.
It is thus a feature of at least one embodiment of the invention to provide a compact mechanism that reduces the unsupported length of the ice-maker and hence the torque on the mounting face.
The housing may provide support journals for the second rotatable shaft at its left and right ends.
It is thus a feature of at least one embodiment of the invention to provide improved rigidity to the cam follower by stabilizing it with widely separated support points on the second shaft.
The cam follower and cam may cooperate to lift and drop the bail at least once with every rotation of the first rotatable shaft.
It is thus a feature of at least one embodiment of the invention to provide a system that positively coordinates operation of the bail arms and the ice-harvesting mechanism.
The cam may be a radially inwardly facing ledge on a gear.
It is thus a feature of at least one embodiment of the invention to provide both a more compact mechanism and one which exerts reduced torque on the drive gear axle from the cam action.
The first and second ends of the second rotatable shaft may include releasable fittings attaching the bail arm releasably to the second rotatable shaft.
It is thus a feature of at least one embodiment of the invention to allow the ice-maker to be pre-manufactured and stocked with the bail arm easily attached at a later time.
The releasable fittings may be snap fittings for engaging with the corresponding element of the bail arm.
It is thus a feature of at least one embodiment of the invention to provide a simple attachment method that may be implemented without tools or additional components.
Alternatively, the releasable fittings may include a screw and corresponding socket holding the bail arm to one of the first and second end of the second shaft.
It is thus a feature of at least one embodiment of the invention to provide a low profile attachment method to reduce the overall width of the ice-maker.
The first and second exposed ends may include key surfaces for engaging corresponding key surfaces in the bail arm locking the two against relative rotation when the key surfaces are engaged.
It is thus a feature of at least one embodiment of the invention to permit the attachment mechanism for the bail arm to restrain only axial separation with torque being transmitted by the key surfaces.
The cam follower may be spring loaded to allow movement of the cam follower without corresponding movement of the second rotatable shaft by flexure of the spring.
It is thus a feature of at least one embodiment of the invention to provide a simple mechanism for preventing damage to the ice-maker if the bail arm is trapped under re-frozen ice. It is another feature of at least one embodiment of the invention to permit the compact drive mechanism to be used without undue risk of damage to the mechanism.
The spring may be a torsion spring extending along at least a portion of the length of the second shaft.
It is thus a feature of at least one embodiment of the invention to provide a spring loading mechanism that may employ space along the axis of the second shaft to reduce the profile of the mechanism.
The ice-harvest drive may further include an electronic sensor element detecting position of the bail arm.
It is thus a feature of at least one embodiment of the invention to provide a mechanism for detecting a height of accumulated ice in an ice bin associated with the ice-maker.
The housing may include a detent element engaging a corresponding element on the second shaft to releasably hold the second shaft in an elevated position when the bail arm is lifted beyond a predetermined point.
It is thus a feature of at least one embodiment of the invention to permit the bail arm to act as a switch for disabling the ice-maker.
The electronic sensor element is selected from the group consisting of a mechanical electrical switch and a Hall Effect electrical switch.
It is thus a feature of at least one embodiment of the invention to provide an ice-maker that can flexibly work with low-cost mechanical switches and Hall Effect switches resistant to contamination.
The ice-harvest drive may further include an electronic sensor element detecting a rotational position of the rotatable shaft.
It is thus a feature of at least one embodiment of the invention to provide a signal allowing interpretation of movement of the bail arm and for control of the ice making process.
The ice-harvest drive may further provide a rear wall opposite the front wall extending between the left and right walls providing attachment points for attaching the housing to support structure.
It is thus a feature of at least one embodiment of the invention to provide a mounting point free from interference with the bail arms and first rotatable shaft.
The attachment point is a set of threaded holes.
It is thus a feature of at least one embodiment of the invention to provide an attachment point consistent with close abutment of the ice-maker to a supporting structure for reduced cantilever torque.
The electric motor is a DC permanent magnet motor.
It is thus a feature of at least one embodiment of the invention to permit the use of a low-voltage motor having reduced shock hazard, heating, and size with respect to AC gear motors.
The ice-harvest drive may further include a resistor for limiting stall current to the DC permanent magnet motor.
It is thus a feature of at least one embodiment of the invention to provide a simple torque limiting mechanism for preventing damage to the ice making components in the event of blockage of the ice-harvesting mechanism.
The motor may communicate with the first rotatable shaft via a combination of spur gears one of which is driven by a worm gear attached to the motor.
It is thus a feature of at least one embodiment of the invention to revise a low profile drive mechanism in which the axis of the motor may lie perpendicular to the separation of the front and back walls of the housing.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of an ice-maker suitable for use with the ice making mechanism of the present invention showing a bail arm for detecting the height of harvested ice cubes on a left side of the drive unit;

FIG. 2 is a front elevational view of the ice-making mechanism of FIG. 1;

FIG. 3 is a front perspective view of the ice-making mechanism showing the bail arm on the right side of the drive unit;

FIG. 4 is a rear perspective view of the ice-making mechanism showing an exposed end of a bail arm shaft keyed for screw attachment of the bail arm;

FIG. 5 is an exploded diagram of the drive mechanism of the present invention showing an internal bail arm shaft, supported at opposite ends on the left and right side of the housing;

FIG. 6 is fragmentary front perspective view of an internal output gear and cam communicating with a cam follower on the bail arm shaft having exposed ends for screw attachment of the bail arms;

FIG. 7 is a fragmentary view an alternative embodiment of the exposed ends of the bail arm shaft providing snap attachment;

FIG. 8 is a side elevational view of the output gear of FIG. 6 showing a home cam on a front surface of the output gear as may trigger a switch to sense a home position of the output gear;

FIG. 9 is a side elevational view of a switch cam attached to the bail arm shaft as may trigger a switch to sense position of the bail arm and showing a mechanical detent for holding the bail arm in the raised position;

FIGS. 10 a and 10 b are rear and front surfaces of the output gear showing the home cam and the bail arm elevating the cam surface.

Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1 and 2, an ice-maker 10 may include an ice mold 12 for receiving water and molding it into frozen ice “cubes” 17 of predetermined but arbitrary shape. The ice mold 12 is adjacent to an ice-harvest drive 14 operating to power a harvesting mechanism to remove cubes from the mold when they are frozen, for example, a harvesting mechanism providing inversion and distortion of the ice mold 12 or a harvesting mechanism using a cube remover comb (not shown) of a type known in the art. The ice mold 12 may be positioned above an ice storage bin 15 for receiving cubes 17 therein when the latter are ejected from the ice mold 12.
The ice-harvest drive 14 may have a coupling 16 extending along a horizontal axis 29 and exposed at a front wall 18 of a housing 20 of the ice-harvest drive 14 to engage the ice-harvest mechanism (for example the mold 12 or a comb). Generally the coupling 16 will rotate about the horizontal axis 29.
The left wall 22 and right wall 24 of the housing 20, flanking the front wall 18, may each present an exposed hub 36 extending outward along a horizontal axis 32 perpendicular to axis 29 from the left wall 22 and right wall 24 respectively. Either one of the hubs 36 may receive one end of a bail arm 30 (shown on the right side only in FIG. 1), the latter which may pivot about the horizontal axis 32 between three positions. At the first substantially horizontal position 27 a (shown in dotted lines), the bail arm 30 is retained by an internal detent (to be described below) to deactivate the ice-maker 10. At a second intermediate position 27 b (also shown in dotted lines), a distal end of the bail arm 30 as held away from a bottom of the ice storage bin 15 also deactivates the ice-maker 10. At a third lowered position 27 c, the distal end of the bail arm 30 is proximate to the bottom of the ice storage bin indicating that more ice may be made and allowing continued function of the ice-maker 10.
Referring now to FIGS. 3, 4 and 5, rotating hubs 36 exposed at the left wall 22 and right wall 24 of the housing 20 may provide key surfaces, in this case, in the form of a hexagonal radial periphery. The bail arm 30 may have a corresponding key socket 39 (shown in FIG. 5) inter-fitting with the key surfaces of the rotating hubs 36 and receiving the hub 36 to be rotationally locked thereto. The bail arm 30 may be attached to the rotatable hub 36, after engagement of the hub 36 and key socket 39, by means of a self tapping screw 41 fitting through a hole 31 in the bail arm 30 at the rotatable hub 36 to be threadably engaged with a corresponding hole 40 in the hub 36 (visible in FIG. 4) extending along the axis 32. The screw 41 retains the bail arm 30 attached to the rotatable hub 36 under the screw head so that they rotate in unison.
Referring now to FIG. 7, in an alternative embodiment the hubs 36 may include snap elements 33, in this case parallel blades extending along axis 32 having outwardly extending hook elements that may be received within a rectangular opening 35 in the bail arm 30. A snap engagement is provided by an inward flexing of the parallel blades to allow the hook elements to fit within the rectangular opening 35 and a subsequent outward springing of the parallel blades once the hook elements clear the rectangular opening 35, whereupon the hook elements engage the bail arm 30 on the far side of the rectangular opening 35. In this case a key socket 39 is not required, the torque-resisting function being provided by the blades of the snap elements 33. It will be appreciated that other methods of attaching the bail arm 30 to the rotatable hub 36 may be used including, for example, ultrasonic staking, adhesive, rivets or the like.
As noted, a rotatable hub 36 is exposed at both the left wall 22 and right wall 24 of the housing 20 so that the bail arm 30 may be attached to either side of the housing 20. In one embodiment, the opposite ends of the bail arm 30 may be mirror images so that a single bail arm 30 may be used when attached on either side of the housing 20 for similar extension from the housing forward over the ice bin 15. In this case, identical key socket 39 and hole 31 are formed in both ends of the bail arm 30 albeit on opposite sides.
Alternatively as shown in FIG. 5, the bail arm 30 may be customized for the particular side of the housing 20 to which it will be attached and its cantilevered end differentiated to provide, for example, additional weight to ensure that the bail arm 30 will swing downward into the bin 15 against the frictional resistance of any attached mechanism.
Referring now to FIG. 5, the two rotatable hubs 36 may be joined by a common shaft 42 extending along the axis 32 therebetween and passing through the housing 20. The common shaft 42 may include journal portions 43 that may be supported by corresponding bearing surfaces 23 formed in the housing 20 so that the shaft 42 is supported at both ends to better resist off-axis torque.
The shaft 42 may support a torsion spring 45 being a wire form extending along the shaft 42 parallel to the axis 32 with inwardly bent ends effectively anchored against rotation near the journal areas 43. A center of the torsion spring 45 is bent outward then back to provide a cam follower 44 that may extend radially from the shaft 42 forward and perpendicular to axis 32 to be received by a cam surface 46 on a rear surface of an output gear 48. The cam follower 44 and cam surface 46 interact so that rotation of the output gear 48 raises and drops the cam follower 44, and thus rotates the shaft 42 and the bail arm 30 appropriately during operation of the ice-maker 10.
Referring also to FIGS. 6 and 10 a, the cam surface 46 may provide a ledge projecting rearward along axis 29 and presenting a surface facing inward toward axis 29, separated from the axis 29 at different radii. The cam follower 44 provided by the torsion spring 45 may rest upon the ledge of the cam surface 46 as biased thereagainst by the weight of the cantilevered bail arm 30. The torsion spring 45 spring loads the cam follower 44 so that if the bail arm 30 and hence the shaft 42 is obstructed in some manner, the cam follower 44 may flex upward as indicated by arrow 47 to permit continued motion of the output gear 48. The upward flexing of the cam surface 46 twists the torsion spring 45 along its wire elements extending along axis 32, as constrained by support blocks 51 projecting from the shaft 42, and bent ends of the torsion spring 45 near the hubs 36 which pass under the shaft 42.
Referring still to FIGS. 5, 6 and also to FIG. 9, one end of the shaft 42 may also support a switch cam 37 and detent arm 34 projecting radially forward from the shaft 42 and axis 32. The distal end of the switch cam 37 may press in on a switch operator 58 a when the bail arm 30 is in a lowered position and may release the switch operator 58 a (as shown in FIG. 9) when the bail arm 30 is raised. The switch operator 58 a may be a flexible strip of metal supported at one end by a printed circuit board 61 (affixed to the housing 20) and extending in cantilevered fashion over a tactile electrical switch 60 a also attached to the printed circuit board 61.
Referring again to FIG. 5, the output gear 48 provides on its front surface the coupling 16 that extends through a bearing opening 19 in the front wall 18 of the housing 20 to operate the ice-harvesting mechanism.
In addition, the front surface of the output gear 48, as shown in FIGS. 8 and 10 b, also supports a home cam 49 that provides a surface extending parallel to axis 29 at one angular location about the axis 29 designating a home rotational position of the output gear 48. Referring to FIG. 8 at the home rotational position of the output gear 48, the home cam 49 will press inward on switch operator 58 b (similar to switch operator 58 a) which may activate tactile switch 60 b providing an indication of the rotational position of the output gear 48.
The electrical signals from the switches 60 a and 60 b will generally provide three types of information: (1) information about how much ice is in the ice bin 15 (shown in FIG. 2), (2) information about whether the consumer wishes to stop ice-making by the ice-maker 10, and (3) information about possible immobilization of the bail arm 30 by ice, each which will be described below.
Referring again to FIG. 5, output gear 48 may be driven by a gear train 50 of multiple spur gears driven by a motor 52, the gear train 50 providing an increase in torque and the reduction in rotation speed of the motor 52 to turn the output gear 48 at about two revolutions per minute. Motor 52 may be a standard low voltage permanent magnet DC motor 54 and communicate with the gear train 50 by means of a worm gear 56 communicating with an outer toothed periphery of one of the gears of the gear train 50. The worm gear 56 may extend generally perpendicular to the axis of the gears of the gear train 50 and the axis 29 of the output gear 48 to reduce the total housing thickness. In the event that the output coupling 16 is blocked, the motor 54 is controllably torque limited by the resistance of its internal windings as tuned by a series resistance 55 in series with windings of the motor 54.
Referring now to FIGS. 10 a and 10 b, during each ice making cycle, generally the output gear 48 will begin in the home position as detected by the home cam 49. This position will locate the output coupling 16 to allow filling of the ice mold 12 with water and freezing of the water into ice cubes.
Once the water has frozen as indicated by a timer or a thermal sensor, the motor 54 may be activated to rotate the output gear 48 from the home position. The first 270 degrees of rotation of the output gear 48 provides for a harvesting of the ice cubes 17 from the ice mold 12 where the ice cubes 17 are released from the ice mold 12 to drop into the bin 15.
At the conclusion of this 360 degrees of rotation, the output gear will align the cam surface 46 so that its greatest radius from axis 29 is aligned with the cam follower 44 allowing the bail arm 30 to drop into the ice bin 15 (shown in FIG. 1) to check the height of the accumulated ice cubes 17. If at this time when the bail arm 30 is allowed to drop by the cam surface 46, the bail arm 30 does not drop sufficiently to activate switch 60 a (shown in FIG. 9) it may be presumed that the ice bin 15 is full. Further filling of the ice cube tray with water for creating additional ice cubes may be stopped until the ice level faults sufficiently to allow full descent of the bail arm 30, although rotations of the output gear 48 are allowed to permit additional height sensing by the bail arm 30.
It will be understood that by this circuitry, elevation of the bail arm 30 can be used by the consumer to turn off the ice-maker 10. Referring to FIG. 9, this latter feature may be facilitated by allowing the detent arm 34 to engage a flexible catch 53 molded into the housing 20 that may releasably retain the bail arm 30 in the elevated position of FIG. 9 against the weight of the bail arm 30 until released by the consumer by downward.
When the output gear 48 returns to the home position, if the bail arm 30 is trapped downward by the ice cubes 17, the switch cam 37 will be retained in its engagement with the switch operator 58 a of FIG. 9 instead of releasing the switch cam 37 as would occur during normal operation. This switch configuration indicates an error condition that may be used by refrigerator logic to also stop further filling of the ice cube trays and effectively to deactivate the ice-maker 10 until the bail arm 30 is freed.
It will be appreciated that the tactile switches 60 a and 60 b may be replaced with other switch types, for example, with Hall Effect sensors triggered by magnets embedded in the cam 37 or 49. It will also be appreciated that other mechanisms such as a crank arm, planetary gear, slot and pin mechanism, and the like may also be used.
Various features of the invention are set forth in the following claims. It should be understood that the invention is not limited in its application to the details of construction and arrangements of the components set forth herein. The invention is capable of other embodiments and of being practiced or carried out in various ways. Variations and modifications of the foregoing are within the scope of the present invention. It also understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention.

Claims

1. An ice-harvest drive comprising:

a housing having a front wall adapted to be positioned adjacent to an ice mold for molding ice cubes, and having right and left sidewalls flanking the front wall;

a first rotatable shaft exposed through the front wall to communicate with the ice mold;

a second rotatable shaft extending between the right and left side walls and having first and second ends exposed through each;

a reciprocating mechanism communicating with the first rotational shaft to provide reciprocation of the second rotatable shaft with rotation of the first rotatable shaft;

a bail arm attachable to one of the first and second ends; and

an electric motor held by the housing to drive the first rotatable shaft.

2. The ice-harvest drive of claim 1 wherein the reciprocating mechanism is a cam attached to rotate with the first rotatable shaft and a cam follower attached to the second rotatable shaft and communicating with the cam.

3. The ice-harvest drive of claim 2 wherein the cam is a radially inwardly facing ledge on gear.

4. The ice-harvest drive of claim 2 wherein the reciprocating mechanism operates to lift and drop the bail at least once with every rotation of the first rotatable shaft.

5. The ice-harvest drive of claim 2 wherein the cam follower is spring loaded to allow movement of the cam follower without corresponding movement of the second rotatable shaft by flexure of the spring.

6. The ice-harvest drive of claim 5 wherein the spring is a torsion spring extending along at least a portion of a length of the second shaft.

7. The ice-harvest drive of claim 1 wherein the housing provides support journals for the second rotatable shaft at its left and right ends.

8. The ice-harvest drive of claim 1 wherein the first and second ends of the second rotatable shaft include releasable fittings attaching the bail arm releasably to the second rotatable shaft.

9. The ice-harvest drive of claim 8 wherein the releasable fittings are snap fittings for engaging with a respective element of the bail arm.

10. The ice-harvest drive of claim 8 wherein the releasable fittings include a screw and corresponding socket holding the bail arm to one of the first and second ends of the second shaft.

11. The ice-harvest drive of claim 1 wherein the first and second exposed ends include key surfaces for engaging corresponding key surfaces in the bail arm locking the ends against relative rotation when the key surfaces are engaged.

12. The ice-harvest drive of claim 1 further including an electronic sensor element detecting position of the bail arm.

13. The ice-harvest drive of claim 12 wherein the housing includes a detent element engaging a corresponding element on the second shaft to releasably hold the second shaft in an elevated position when the bail arm is lifted beyond a predetermined point.

14. The ice-harvest drive of claim 12 wherein the electronic sensor element is selected from the group consisting of a mechanical electrical switch and a Hall effect electrical switch.

15. The ice-harvest drive of claim 1 further including an electronic sensor element detecting a rotational position of the rotatable shaft.

16. The ice-harvest drive of claim 1 wherein the electric motor is a DC permanent magnet motor.

17. The ice-harvest drive of claim 16 wherein further including a resistor for limiting stall current to, and torque provided by, the DC permanent magnet motor.

18. The ice-harvest drive of claim 16 wherein the motor communicates with the first rotatable shaft via a combination of spur gears one of which is driven by a worm gear attached to the motor.