WO1996001554A1

WO1996001554A1 - Flotation control system

Info

Publication number: WO1996001554A1
Application number: PCT/GB1995/001613
Authority: WO
Inventors: James Fraser Mitchell
Original assignee: Reekie Manufacturing Limited
Priority date: 1994-07-07
Filing date: 1995-07-07
Publication date: 1996-01-25
Also published as: GB9514547D0; AU2893195A; GB2290935B; GB2290935A; GB9413654D0

Abstract

The present invention relates to a control system for use with ground traversing machinery (1) having a subframe (4) hung at a first subframe portion (6) from a mainframe (10) of the machinery (1) and provided, at a second subframe portion (12) remote from the first subframe portion (6) with ground engaging means such as diabolo rollers (16). Auxiliary hanging means (18-22) are provided for hanging the subframe (4), at a position remote from the first subframe portion (6), from the main frame (10) and the auxiliary hanging means (18-22) are provided with a load control system for varying the degree of support provided to the subframe (4) by the auxiliary hanging means (18-22). The control system comprises a static pressure sensing means (50) provided for acting between the ground engaging means (16) and the subframe (4) for monitoring the loading on the ground engaging means (16). A user adjustable control means for setting predetermined load values is provided as is a processor means for comparing the measured loading with the predetermined loading. Drive means (24, 26) formed and arranged for increasing or decreasing the degree of support provided by the auxiliary hanging means (18-22) respond to detection of excursions of the measured loading below and above the predetermined value whereby in use of the machinery (1) the loading exerted on the ground through the subframe (4) ground engaging means (16) may be controlled.

Description

FLOTATION CONTROL SYSTEM The present invention relates to a control system for sensing the pressure exerted upon the ground by a roller (or other ground engaging element) of the type used in agricultural machinery, but not exclusively.

Potato harvesters having a subframe for supporting a separating mechanism and a series of "Diabolo" rollers (i.e. a concave rolling surface roller that runs on top of a potato ridge (or at least one potato ridge) ) are generally well known. The subframe of such harvesters is hingedly supported at a trailing end of the harvester mainframe, the front end of which is mounted to and supported by a tractor via a conventional three-point linkage or draw bar. The "Diabolo" rollers roll over the top of the ridging, so as to support, at least partially, the shares and the separating mechanism of the harvester into the required relationship with the ground for harvesting. It will be understood that the depth to which the separator mechanism penetrates the soil to be harvested and the control thereof is critical to the efficiency of such harvesters.

Conventionally the 'Diabolo¹ rollers are mounted to the subframe and are provided with manual adjustment means to vary and set the relationship between the separator ar the shares with respect to the rollers i.e. a preset gap between the rollers and the share. The subframe for supporting the separator and the "Diabolo" rollers is provided with a user operable hydraulic mechanism for adjusting, relative t~> the harvester mainframe, the displacement of the subframe with respect to the harvester mainframe. A particular problem with such known designs of harvester having subframe adjustment means is when the harvester is used in variable soil and weather conditions. Thus for example in dry weather/soil conditions there is a tendency for the diabolo rollers to bulldoze the generally frangible dry soil of a ridge(s) resulting in possible damage to potatoes and in conditions of wet soil for the soil to be compacted such that the separator is unable efficiently to separate soil from potatoes or at least requires to harvest at substantially reduced speed in order to allow more time for soil separation. It will be appreciated that such wet and dry soil conditions can be found at the same time in different parts of the same field and thus a setting suitable for use in one part of a field having more or less dry soil conditions is unsuitable in another part of a field having more or less wet soil conditions, thereby requiring an operator to stop and start the harvester and to make manual adjustment to the relationship of the subframe to the mainframe to compensate for variations in loading based on the operator's judgement. In some circumstances less conscientious operatprs fail to stop to make the necessary adjustments resulting in crop damage and/or inefficient harvesting.

Automatic systems are known for adjusting the relationship between the subframe and the mainframe and rely on the diabolo rollers moving with respect to the subframe between a first manually adjustable upper limit position and a second manually adjustable lower limit position whereby when the ridges exert an excessive force on and movement of the rollers, a sensor detects that movement when it passes the upper limit and actuates, via control means, hydraulic drive means to raise the subframe. When the rollers are only lightly loaded, or not loaded at all, the diabolo rollers move towards the second lower limit and a sensor detects that movement and thereby actuates, via the control means, said hydraulic drive means to lower the subframe so as to bring the rollers into contact with the ridges. It has been found that the movement of the rollers with respect to the subframe of this known system results in the subframe being driven or "hunting" up and down, due to the movement of the rollers between the upper and lower limits on the subframe which results in unsatisfactory potato harvesting by such known designs due to the inability to control accurately the vertical positioning of the subframe and thereby the depth of the separator into the ground. Moreover, as such known systems utilize a spring of one form or another to dampen movement between the upper and lower limits, it has been found that even small compressions of the spring in the order of 1 to 2 mm, result in the pre-set gap between the rollers and the share increasing transiently by up to 6 to 8 mm. Furthermore if the control system of such known designs is switched off, as may be the requirement from time to time, the spring may become fully compressed for example by up to 15 mm as the roller moves upwardly resulting in the pre-set gap between the rollers and the shares increasing transiently by up to 40 to 45 mm. Such deviations from the pre-set gap between the rollers and the share result in significantly reduced efficiency of the harvester.

A known type of potato harvester having diabolo rollers with manual adjustment means is shown in Fig. 1 and the detailed view of Fig. 2 shows the subframe for supporting the rollers and the separator.

It is an object of the present invention to avoid or minimise one or more of the foregoing disadvantages.

The present invention provides a control system for use with ground traversing machinery having a subframe hung at a first subframe portion from a mainframe of said machinery and provided, at a second subframe portion remote from said first subframe portion, with ground engaging means; auxiliary hanging means being provided for hanging said subframe, at a position remote from said first subframe portion, from said main frame, said auxiliary hanging means being provided with a load control system for varying the degree of support provided to said subframe by said auxiliary hanging means, characterized in that said control system comprises a static pressure sensing means provided for acting between said ground engaging means and said subframe for monitoring the loading on said ground engaging means, user adjustable control means for setting predetermined load values, processor means for comparing the measured loading with said predetermined loading, and drive means formed and arranged for increasing or decreasing the degree of support provided by said auxiliary hanging means in response to detection of excursions of the measured loading below and above said predetermined value whereby in use of the machinery the loading exerted on the ground through said subframe ground engaging means may be controlled.

Thus with a control system according to the present invention the ground engaging means of a piece of machinery, such as a potato harvester, may be controlled in an accurate manner such that the loading exerted on the ground may be maintained at a more or less predetermined loading without any movement between the rollers and the shares thereof.

Preferably said ground engaging means is supported from said subframe by a first linkage means so as to allow movement of said ground engaging means up and down relative thereto; a first portion of said static pressure sensing means is mounted from said subframe, and a second portion of said static pressure sensing means is engagable by an abutment means connected to said first linkage means so as to apply pressure to said static pressure sensing means when said ground engaging means engages the ground to support said subframe thereon.

Advantageously said abutment means comprises an abutment portion on a second linkage means connected to said first linkage means so as to apply increasing pressure to said static pressure sensing means through said abutment portion when an increasing upward force is applied to said ground engaging means. Conveniently said second linkage means comprises a lever means having a first portion pivotally mounted from said subframe and a second portion coupled to a second linkage means member coupled in turn to said first linkage means, said second linkage means member being formed and arranged for transmitting pressure to said lever means second portion when said ground engaging means is forced upwardly. Conveniently said second linkage means member has a first portion secured to said first linkage means and a second portion captively engaged with said lever means second portion so as to be slidable relative thereto, said second linkage means member being further provided with a first stop means secured thereto for engagement with said lever means second portion when said ground engaging means is forced upwardly. Desirably said second linkage means member is provided with a second stop means secured thereto for engagement with the upper side of said lever means second portion when said ground engaging means is not in contact with the ground but supported by the auxiliary hanging means.

Most conveniently said second linkage means member first portion is screwthreadedly connected to said first linkage means so as to allow adjustment of the height of said ground engaging means relative to said stop means thereby to adjust the operating height of the ground engaging means relative to the subframe and any tools or the like mounted therefrom. Desirably said second linkage means member first portion is provided with locking means for securing said first linkage means thereto.

Preferably said ground traversing machinery is in the form of a potato harvester drawn and powered by a tractor and said ground engaging means is in the form of at least one diabolo roller formed and arranged for rolling over the top of at least one potato ridge, or a wheel and tyre arrangement for rolling along the furrow between adjacent ridges. Alternatively said ground traversing machinery may be self-propelled.

The present invention is not restricted to potato harvesters and is also applicable to any type of harvester for harvesting carrots, beetroot or other root crops which may be grown on a bed as opposed to a ridge.

Preferably said auxiliary hanging means is in the form of a remote linkage connected to a hydraulic piston/cylinder arrangement of generally known type and construction whereby an operator of the tractor can adjust, from the tractor, the relationship between the subframe and the mainframe.

Advantageously the ground engaging means, in the form of diabolo rollers or the like, is provided with manual height/depth adjustment means of a type and construction substantially similar to that provided on existing machinery so that an operator can set a fixed distance between the shares of a harvester and the ground engaging means and hence the depth to which the shares of the harvester penetrates the soil/ground. Conveniently the control system of the present invention may be simply and readily fitted to existing machinery without the need for expensive and time consuming fitting operations.

Preferably said static pressure sensor means is in the form of a draught sensor in the form of a bearing pin. Preferably said static pressure sensor means is formed and arranged to support substantially said ground engaging means via a drop link of said subframe when said ground engaging means is not engaging the ground. Desirably the upper portion of said drop link is slidably engaged between end stops with said auxiliary hanging means to allow upwards transient movement of said ground engaging means over, for example, large rocks etc.

Preferably said user adjustable control means is remote from said machinery and conveniently may be placed in the cab of the tractor used for drawing and powering said machinery so that the user may make adjustments to the control system whilst in use thereof.

There may also be provided on for example a full width double ridge diabolo roller two (or more) spaced apart pressure sensor means so as to provide independent side to side sensing of the load. Such an arrangement has applications in providing a level control system for use with ground traversing machinery. Further preferred features and advantages of the present invention will appear from the following detailed description given by way of example of some preferred embodiments illustrated with reference to the accompanying drawings in which:- Fig. 1 is a perspective view of a conventional potato harvester;

Fig. 2 is a detailed perspective view of the diabolo roller support subframe of the potato harvester in Fig. 1 shown in enlarged scale; Fig. 3 is a detailed partial perspective view of the subframe in Fig. 2 with the static sensor of the control system of the invention;

Fig. 4 is a partial side view of the embodiment of the control system of the invention shown in Fig. 3; and Fig. 5 is a partial side view of a second embodiment of the invention.

Fig. 1 shows a potato harvester, generally indicated by reference number 1, of the type which is drawn and powered by a tractor (not shown) via a draw bar linkage 2.

In more detail and with reference to Fig. 2 the generally conventional harvester 1 has a subframe 4 (shown solid in Fig. 1) which is hung at its trailing end 6 by a pivot arm assembly 8 to the mainframe 10 of the harvester 1 (shown only partially in Fig. 2) . The leading end 12 of the subframe 4, which incorporates the shares (not shown) for harvesting potatoes, has a cross beam 14 for supporting two diabolo rollers 16 and four cutting blades 17. The cross beam 14 and the rollers 16 are hung with respect to the mainframe 10 by an upwardly extending drop link 18 connected via a pivoting linkage 20 to a rotatable drive arm 22. The arm 22 is driven via a connecting rod 23 by an hydraulic piston 24 and cylinder 26 arrangement. Return springs 28 are provided between the piston 24 and the cylinder 26. It will be understood that by activating the piston 24 and cylinder 26 arrangement it is possible to control the degree of support provided to the subframe 4 by the drop link 18 and the pressure exerted by the rollers 16 on the potato ridges on the ground (not shown) .

Each diabolo roller 16 is mounted to the rear of the cross beam 14 on a main pivoting 30 link 31 so that the roller 16 may move up and down with respect to the subframe 4 for instance when passing over an undulation on a potato ridge. A flotation control link 32 having a screw connection adjustment 34 is provided between a forward facing mounting plate 36 on the cross beam 14 and a trunnion 37 on the main pivot link 31. The flotation control link 32 controls the distance between the shares and the diabolo rollers 16 and the depth to which the shares of the harvester penetrate the ground/soil. The flotation control link 32 has a handle portion 38 so that it may be screwed up or down according to the depth required. The flotation control link 32 is provided with upper 40 and lower 42 end stops for limiting the displacement of the rollers 16 with respect to the subframe 4. The upper and lower end stops 40, 42 may be adjusted on the flotation control link 32 to limit the displacement of the rollers 16 with respect to the subframe 4.

Figs. 3 and 4 show in detail the modified arrangement of mounting plate, indicated by reference number 36a, for use with the control system of the present invention for use with the potato harvester of the type described with reference to Figs. 1 and 2.

The mounting plate 36a is clamped to the cross beam 14 by four elongate bolts 44 which engage with a rear facing mounting plate 37 on which the main pivoting 30 link 31 pivots (shown partially in dotted line and on one side only in the interests of clarity) . The forward facing mounting plate 36a has two spaced apart parallel projecting lugs 46 each having a large central aperture 48 for receiving a draught pressure sensor 50. Between the two spaced apart lugs 46 are two spaced apart plates 52, also having a central aperture 48a for receiving the draught sensor 50, the forward projecting ends 54 of which are pivotally 56 mounted to the lugs 46. The trailing ends 58 of the plates 52 are spaced apart by a upper trunnion 60 in which is slidably mounted the depth control link 32 shown in Fig. 2. The flotation control link 32 is provided with a lower 42 end stop which abuts against the underside of the trunnion 60 in use of the system. The lower end 32a of the flotation control link 32 is screwably attached through a lower trunnion 61, pivotally connected between the pivoting links 31. Optionally there is provided a locking nut 62 to lock the link 32 into the lower trunnion 61 (see Fig. 3) .

It will be appreciated from the foregoing description that upward movements of the roller 16 are transferred through the flotation control link 32 into the upper trunnion 60 which acts on the two spaced apart plates 52 which tend to try and rotate about the pivot 56. Such upward movement of the rollers 16 results in an increased load/pressure which is detected by the draught pressure sensor 50. (Suitable draught pressure sensors are made by the Bosch organisation of Germany.)

The control system according to the present invention further comprises a user adjustable control panel (conveniently situated in the cab of the tractor) for setting, by the user, predetermined load values and a processor P, connected to the sensor 50 by a wire 63, for comparing the measured loading, as detected by the draught pressure sensor 50, with the predetermined load values. When the processor P detects excursions of the measured loading below or above the predetermined value, the processor causes the piston 24 and cylinder 26 arrangement to be actuated so as to increase or decrease, as required, the degree of support provided to the subframe 4 by the drop link 18 and the mainframe 10. The draught sensor 50 of the present embodiment is formed and arranged with the processor P such that when there is no upward force exerted by the rollers or at least only a small force the processor detects this and actuates the piston and cylinder arrangement so as to drive the subframe and hence the rollers and the shares down further. It will be appreciated that as there is no movement of the rollers with respect to the subframe the gap between the rollers and the shares remains constant thereby ensuring efficient harvesting. Moreover even if the control system of the present invention is switched off the harvester may be used in a conventional manner similar to the harvester in Figs. 1 and 2.

The embodiment shown in Figs. 3 and 4 also include a top end stop 40 which is in contact with the trunnion 60. This end stop may be positioned further up the flotation control link 32 inasmuch as it is not essential to the operation of the flotation control system, but allows for the diabolo roller to make sudden transient downward movements into, for example, a hole and return to its normal position before the top end stop 40 exerts a force on the draught sensor and thus before the processor has detected the downwards deviation from the predetermined value, and actuated the piston 24 and cylinder 26 arrangement to lift the rollers 16. The top end stop 40 also allows the diabolo rollers to drop as the harvester passes over the end of a bed being harvested and thereby to come closer to the shares thus preventing potatoes 63 on the shares 65 or an open web conveyor 69 to fall off the bottom of the harvester 1.

Shown also in Figs. 3 and 4 is a scraper plate 64 which is mounted between the two spaced pivot links 31 and having a complimentary shape extends into the flat bottomed, generally U-shaped section diabolo roller 16 to prevent any earth or the like building up on the surface of the diabolo roller and thereby giving rise to apparent deviations from the normal predetermined values as the rollers 16 traverse the generally flat bed 65 to be harvested.

Fig. 5 shows a modified form of second linkage means suitable for use when a higher degree of flotation control sensitivity is required. The mounting plate is bolted 44 to the cross beam (not shown) as before and has two large rectangular spaced apart projecting panels 46 (one only shown in dashed outline) between which is pivotally mounted 66 at one end 67 a lower support member 68. The distal end 70 of the lower support member 68 has an aperture 71 in which is slidably connected a flotation control link 32 (generally similar to that in Figs. 3 and 4) having a lower end stop 42 abutting against the underside of the lower support member 68. Proximal said one end 67 of the lower support member 68, an upwardly extending link member 72 acts against the distal end 37 of a shorter upper support member 74 which is pivotally mounted 76 at one end 78 to the two spaced apart plates 46. At a central part of the upper support member 74 is provided an aperture 48. The spaced apart plates 46 have corresponding apertures 49 and are formed and arranged together with the aperture 48 in the upper support member 74 for receiving a draught pressure sensor 50. It will be seen that the arrangement of the support and pivot members 68, 72, 74 allows for very small load or pressure deviations in the rollers acting through the flotation control link 32, as they pass over the ground, to be detected by the draught sensor 50 and for a significantly higher degree to be achieved. It will of course be appreciated further that a draught pressure sensor 50 having an increased level of sensitivity may be used with the embodiment described above with reference to Figs. 3 and 4.

Claims

1. A control system for use with ground traversing machinery (1) having a subframe (4) hung at a first subframe portion (6) from a mainframe (10) of said machinery (1) and provided, at a second subframe portion (2) remote from said first subframe portion (6) with ground engaging means (16) ; auxiliary hanging means (18-22) being provided for hanging said subframe (4) , at a position remote from said first subframe portion (6) , from said main frame (10) , said auxiliary hanging means (18-22) being provided with a load control system for varying the degree of support provided to said subframe by said auxiliary hanging means (18-22) characterized in that said control system comprises a static pressure sensing means (50) provided for acting between said ground engaging means (16) and said subframe (4) for monitoring the loading on said ground engaging means (16) ; user adjustable control means for setting predetermined load values; processor means for comparing the measured loading with said predetermined loading; and drive means (24, 26) formed and arranged for increasing or decreasing the degree of support provided by said auxiliary hanging means (18-22) in response to detection of excursions of the measured loading below and above said predetermined value whereby in use of the machinery (1) the loading exerted on the ground through said subframe (4) ground engaging means (16) may be controlled.

2. A control system as claimed in claim 1 wherein said ground engaging means (16) is supported from said subframe (4) by a first linkage means (31) so as to allow movement of said ground engaging means (16) up and down relative thereto; a first portion of said static pressure sensing means (50) is mounted from said subframe (4) and a second portion of said static pressure sensing means (50) is engagable by an abutment means (60) connected to said first linkage means (31) so as to apply to pressure to said static pressure sensing means (50) when said ground engaging means (16) engages the ground (65) to support said subframe (4) thereon .

3. A control system as claimed in claim 2 wherein said abutment means (60) comprises an abutment portion on a second linkage means connected to said first linkage means (31) so as to apply increasing pressure to said static pressure sensing means (50) through said abutment portion when an increasing upward force is applied to said ground engaging means (16) .

4. A control system as claimed in claim 3 wherein said second linkage means comprises a lever means (54) having a first portion pivotally (56) mounted from said subframe (4) and a second portion coupled to a second linkage means member coupled in turn to said first linkage means, said second linkage means member being formed and arranged for transmitting pressure to said lever means second portion when said ground engaging means (16) is forced upwardly.

5. A control system as claimed in claim 3 or 4 wherein said second linkage means member (32) has a first portion (32a) secured to said first linkage means (31) and a second portion (32b) captively engaged with said lever means second portion so as to be slidable relative thereto, said second linkage means member (32) being further provided with a stop means (42) secured thereto for engagement with said lever means second portion when said ground engaging means (16) is forced upwardly.

6. A control system as claimed in anyone of claims 3 to 5 wherein said second linkage means member first portion (32a) is screwthreadedly connected to said first linkage means (31) so as to allow adjustment of the height of said ground engaging means (16) relative to said stop means (42) thereby to adjust the operating height of the ground engaging means (16) relative to the subframe (4) and any tools or the like mounted therefrom.

7. A control system as claimed in anyone of the preceding claims wherein said ground engaging means is selected from a standard single diabolo roller; a double diabolo roller; a full width diabolo roller; or a wheel and tyre arrangement.

8. A control system according to anyone of claims 1 to 7 wherein said static pressure sensor means is in the form of a draught sensor bearing pin (50) .

9. A harvester (1) having a control system according to anyone of claims 1 to 8.