GB1588957A

GB1588957A - Conveyor

Info

Publication number: GB1588957A
Application number: GB28098/76A
Authority: GB
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1976-07-06
Filing date: 1976-07-06
Publication date: 1981-05-07
Also published as: BE856551A; ZA773988B

Description

(54) CONVEYOR (71) We, FMC CosPozATtoN, a corporation organised and existing under the laws of the State of Delaware, United States of America of 200 E. Randolph Drive, Chicago, Illinois, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to conveyors for example conveyors used for collecting harvested tree, bush or vine grown crops such as currants, berries, grapes or any other produce grown on trees, or standing bushes or vines.

Conveyors for receiving and/or conveying objects delivered from above are well known, but it is a drawback with such known conveyors that they often do not catch the majority of the objects being delivered. Thus, when the conveyors are mounted on a machine such as a harvester which moves over the ground, the conveyors, which act as catcher conveyors for harvested fruit, usually do not catch all the harvested fruit which can result in a loss of as much as 50% of the crop. Also, in a field of plants there are obstacles such as the plants themselves, posts and the like which foul the conveyors resulting in damage or a slowing down of the harvesting operation. These considerations effectively require that the conveyors have a zero ground speed. Such a conveyor system is shown in U.S. Patent No. 3 901 005 to Rohrbach et al. The drive for the catcher conveyors in the aforesaid Rohrbach Patent is synchronised with the drive train to drive wheels of the conveyor and hence will not be effective if the drive wheels slip on the ground over which the harvester moves.

According to the present invention there is nrovided an endless conveyor comprising individual conveying elements together defining a conveying reach and at least part of each of which elements is movable or compressible in a direction laterally of the conveying direction of the conveying reach while the orientation of said part of each element is maintained substantially constant in relation to the direction of motion of the conveyor at each corresponding point along and throughout its path of travel.

Further according to the present invention there is provided for a harvesting machine, for harvesting tree, bush, cane- or vineborne crops such as currants, berries or grapes, having a frame which can be moved along a row of standing trees, bushes, canes or vines and which supports a shaker or beater device to release cron from the trees, bushes or vines, an endless conveyor having a conveying reach drivable in a conveying direction and having individual conveying elements at least a vart of each of which element is movable laterally of the conveying direction of the said conveying reach, the elements being shaped and disposed to catch crop released by the shaker or beater device and means mounting the said part of each element constraining the part to maintain a substantially constant orientation in relation to the direction of motion of the conveyor at each corresponding point along and throughout the path of travel of that point.

Still further according to the present invention there is provided an endless conveyor comprising flexible drive means movable along a predetermined endless path, conveying elements mounted on the drive means at least a part of each of which elements is displaceable laterally with respect to the direction of motion of the drive means, and means mounting the conveying elements on the drive means such that throughout the predetermined endless path the orientation of each said part of each said conveyor element remains substantially constant relative to the part of the drive means mounting the said element.

As incorporated in a harvester for harvesting berries or grapes, the harvester may be of the straddle type and include a pair of conveyors as hereinbefore defined of which the elements are adapted to extend into the central passageway through the harvester and to catch and convey harvested berries or grapes.

Constructions embodying the invention are diagrammatically illustrated, by way of example, in the accompanying drawings, in which: Figure 1 shows a partial front elevational view of a harvester for tree, bush or vine grown crops including two conveyors in accordance with the invention; Figure 2 is an underneath plan view of part of one of the conveyors of Figure 1; Figure 3 is a fragmentary underneath plan view, to an enlarged scale, of one element of the conveyor of Figure 2; Figure 4 is a side elevational view of the element of Figure 3; Figure 5 is a Dlan view of part of the conveyor of Figures 2 to 4 showing retraction of the elements at the upper conveyor run; Figure 6 is a schematic view in plan of the conveying features of the harvester of Figure 1; Figure 7 shows a schematic side elevational view of the conveyor of Figures 2 to 6 of the harvester; Figure 8 is a schematic perspective view from above and in front of a harvester for tree, bush or vine grown crops with parts such as main and sub-frames and shaker devices removed for clarity but showing a second embodiment of conveyor, of which there are two extending longitudinally of the harvester; Figure 9 shows a detail of the operation of the second embodiment of conveyor; Figure 10 shows a plan view of a crop catching/conveyor run of one of the conveyors of the second embodiment; Figure 11 shows a plan view, with part in phantom, of one element of the second embodiment of conveyor; Figure 12 shows a side elevational view, with part in phantom, of one element of the second embodiment of conveyor; Figure 13 shows a side elevational view of a second embodiment of conveyor in position on a harvester; Figure 14 shows a transverse cross-section on line A-A of Figure 13; Figure 15 shows a transverse crosssection on line B-B of Figure 13; Figure 16 shows a schematic perspective view of another arrangement of the second embodiment of conveyor, with details of the harvester itself omitted.

Figure 17 shows a third angle projection of a speed-matching device for maintaining zero ground speed of the first or second embodiment of conveyors; Figure 18 shows a schematic side elevational view of harvester in which the height of the conveyors can be adjusted; and Figure 19 is a cross-section of a catcher trough or tray forming a part of a conveying element of a conveyor in accordance with te second embodiment of the invention.

Referring firstly to Figures 1 to 7 of the drawings, there is shown, on a berry or grape harvester 1, a pair of generally parallel crop-catching and conveying conveyors 2. Each conveyor 2 has a body 3 in the form of a pair of parallel driven chains 4 and a plurality of individual elements 5 each of which is movable in a direction laterally of the direction of movement of a crop catching and conveying reach of the conveyor.

Each element 5 is in the form of a rectangular trough or tray of which the long sides are at right angles to the conveying direction. Each tray 5 has a lip 6 at the free edge of one long side which overlaps a free-edge 7 of the other (unlipped) long side of one adjacent element of the conveyor. In this way, no gaps are formed in the conveyor at least during passage along the conveying reach so that juice is held in the trays 5 with harvested berries or grapes.

The chains 4 of each conveyor carry a plurality of pairs of parallel rods 8. Each pair of rods 8 forms a guide on which a seat part of cam follower, in the form of two tubular sleeves 9 on the under side of each tray 5, can move during the lateral movement of the tray.

The traps 5 are each urged towards the centre line of the harvester by a device in the form of a rubber spring 10 under the tray 5 which extends from an anchorage 11 on a part of the outer (relative to the longitudinal centre line of the harvester) chain round a roller 12 on the inner chain to an anchorage 13 on the underside of the tray 5 (see Figure 3).

The tensions of the springs 10 urge their respective trays 5 towards the longitudinal centre dulling an upper, cropl catching/ conveying, run of the conveyor.

Each tray 5 of the conveyors 2 also has a cam follower in the form of a roller 14 (Figure 5) at one end. The roller 14 is below the level of the upper reach of the chains 4 and is positioned so that it engages a cam in the form of a striker bar 15 for retracting the trays 5 to positions substantially centered with resnect to the chains for the return run. During the return run, the conveyor runs conventionally, the spring pressure being accommodated by a guide wall 16 (which as a flared entry 17) via suitable low friction means such as pressure pads or rollers, for example of nylon. A low pressure absorption means such as another wall (not shown) is attached to the outside of the chain.

The conveyors 2 are driven by a hydraulic or mechanical motor of the harvester.

During harvesting, the conveyors have a zero velocity with respect to the harvester, that is to say the conveyors are driven with their conveying reaches in a direction opposite to the direction of the harvester but at substantially the same speed by means hereinafter described and also described and claimed in our co-pending application 7926971 (Serial No. 1 588 958).

In operation to harvest grapes for example, the harvester 1 is driven along a row of vines so that it straddles the row.

The direction of movement is shown by the arrow 'X' in Figure 6. The conveying runs of the conveyors 2 move as shown at 'Y ' in Figure 7, in the opposite direction relative to the harvester but at the same speed as the harvester. As a result the effective speed of the conveying reach of the conveyors 2 at a vine is zero so that the harvested grapes drop into a seemingly stationary series of trays 5 which are the conveyor elements. This is accomplished by synchronising the speed of the conveyor relative to the speed of the harvester, preferably by means (hereinafter described) whereby slippage of the drive ground system of the conveyor or of the wheels does not affect the synchronism. The conveyors 2 each have an upper conveyor run 18, then an upwardly inclined run 20 before a return (lower) run 19 in which the trays are open downwardly. During transition from the upwardly inclined run to the lower run, the grapes are transferred to collecting tubs or other suitable collectors (not shown), as well as described in connection with Figure 18.

It will be noted that the trays or troughs 5 of the first embodiment maintain their orientation relative to the corresponding links of the drive chains constant irrespective of their positions in the conveyor runs.

In order to cover the centre space 21 of the harvester (normally about 18" in conventional harvesters) the trays 5 are urged to the centre line of the harvester by their springs 10 as they start their upper conveying run. This is progressively accomplished as their rollers 14 travel along an inclined forward striker bar 15 which is angled to an optimum angle, which may be adjusted.

The right hand and left hand conveyor trays meet at approximately the centre line, as shown at 'A' and 'B'. In order to accommodate possibly different tensions in the springs, the trays are arranged so that they can overlap the centre line and the entire space 21 is substantially covered.

The harvested berries run down inclined side screens 22 of the harvester into the trays 5, any gap being closed by a sealing device in the form of a nylon brush 23 which extends along the harvesting length of the harvester.

When the harvester approaches a vine or another obstruction such as a concrete post 24, the trays move only as far as that obstruction, as shown at ' C ' and 'D' because in effect the conveyors are stationary with respect to the obstruction as well as with respect to the ground. The trays 5 are held lightly against the obstruction by the springs 10 so that any gap is minimised.

The second embodiment of conveyor and its operation will now be described with respect to Figures 8 to 18. There are two conveyors 26 one on either side of the longitudinal axis of the harvester. As they are identical, only one will be described in detail. Each conveyor 26 comprises a pair of endless chains 27 which extend the length of the conveyor in a crop catching/ conveying reach 28, passes around sprockets 29, 30 (the upper one 30 of which is driven) at each end of the harvester and has a return run 131 which is either a lower reach or run (Figures 8, 13 to 15) or an upper reach or run (Figure 16) of the conveyor.

In the form shown in Figures 13 and 14, a discharge chute C is provided which delivers the crop and juice to collectors (not shown) when the trays are inverted as their chains pass around sprockets 30 at the ends of the crop catching reaches 28.

In each case, the crop catching/conveying reach 28 moves in a direction opposite to the direction of movement of the harvester over the ground. The driven sprockets 30 are driven by a hydraulic motor 30a powered by a prime mover 49. The speed the sprockets 30 and hence of the conveyors 26 is, in use, virtually instantaneously controlled by a speed-sensing control unit 51 to be equal and opposite to the ground speed of the harvester so that the effective ground speed of the conveyors is zero.

The chains 27 support a plurality of guides in the form of transverse rods 31.

The rods 31 are of metal covered at 31a (Figure 14) with a low-friction bearing surface 31b such as a nylon coating and are arranged in pairs. Each pair of rods 31 supports an elongate member comprising a trough or tray 32 and a cam follower 33.

Successive trays 32 overlap in the direc tion of the working run (by iF" in the embodiment shown) to provide a substan tially continuous conveying and catching surface.

Each tray as shown in Figure 19 has an optimum shape for holding a maximum of harvested crop and to this end has an open mouth leading to two compartments which extend across the length of the tray and are defined by an interior partition wall 34 which extends parallel to the transverse boundary walls 34a and 34b of the tray.

The cam follower 33 and the trays 32 are movable on the rods 31 in a direction laterally of the crop catching/conveying reach of the conveyor. Each tray 32 is secured as by bolts 35 to a carrier 36 which includes two tubes 37 slidable on the nylon coating 31b of the rods 31. The cam follower 33 is likewise supported as by a bolt 39 on a carrier 40 in the form of two tubes 41 (Figures 11, 12, 14). The bolt 39 also forms an anchorage for one end of a tension spring 42 (Figure 14), the opposite end of which is secured in the carrier 36 for the tray, as by having its hooked end engaged through holes in the outer wall 36a of that carrier 36 and passing through an aperture in the inner wall 36b of the carrier The harvester also has two cams 43, one for each conveyor and one of which is shown in Figure 10. Each cam 43 has an inclined lead-in portion 44 at the front end of the harvester, a straight portion 45 and an inclined lead-out portion 46 at the trailing end of the harvester.

The lead-in portion 44 of each cam 43 has an angle of 45" and the lead-out portion 46 has an angle of 3%. The shallower angle of the lead-out portion 46 provides a relatively slow withdrawal motion of the (full) trays so that harvested fruit in the trays is not lost by a too rapid change of direction which could lead to jolting, with consequent loss of fruit.

Use of the conveyor 26 will be described with reference to the conveyor having a lower return run though it will be understood that the upper return run conveyor of Figure 16 operates in a similar way.

Using the conveyors for harvesting grapes or blackcurrants for example, the harvester is driven along a row of plants so that it straddles the row. The conveyors 26 move in the opposite direction but at the same speed relative to the harvester. As a result the effective speed at a plant is zero so that the harvested fruit drops into a seemingly stationary series of trays 32 which are the conveyor elements. This is accomplished by synchronising the speed of the conveyor relative to the ground speed of the harvester, by the speed sensing control unit 51 arranged so that slippage of the drive system of the conveyor or of the ground wheels does not affect the synchronisation.

As seen in the highly schematic diagram of Figure 8, the straddle harvester has at least one driving ground wheel 47 having an actuator 48 driven by the prime mover 49, as is well known in the art and is described in the specification of United Kingdom Patent No. 1 390 495. The prime mover 49 also drives a hydraulic pump 50 that provides fluid under pressure for driving the hydraulic motor 30a for the catcher con veyor 26 which also has the speed sensing control or synchronism unit 51 for providing relative zero velocity of the conveying reach of the conveyor 26 and ground. This unit is shown in Figure 8 and in more detail in Figure 17 and essentially comprises a comparator device in the form of a three shaft differential gear box 51, a hydraulic pressure compensated flow control valve 53 coupled to one 54 of the shafts (an output shaft) of the differential gear box 53, the fixed displacement hydraulic motor 30a to drive one of the objects to be matched in speed, in this case the conveyor 26 (shown schematically on 8 schematic harvester 100 in Figure 17), a fixed displacement hydraulic motor 55 coupled to one 56 of the shafts (an input one of this embodiment) of the differential gear box 51, and the hydraulic pump 50 for supplying fluid under pressure to the hydraulic flow control valve 53. The differential gear box 51 comprises a spider gear 58 mounting a spider 60 of channel or box shape (Figure 17) and rotates in bearings 65. A shaft 59 mounts an input side control gear 61 and the output shaft 54 mounts an output side control gear 62 opposed to the gear 61. The spider 60 supports a fixed shaft 60a which supports opposed idler gears 63 which mesh with the input and output control gears 61 and 62.

The shaft 56 mounts a spider pinion gear 64 in mesh with the spider gear 58. The shafts 54 and 59 are free to rotate independently of the spider gear 58 and spider 60 in bearings 66. The differential gear box 51 is encased in an oil tight case.

In operation, the unit has essentially three modes, viz. starting, steady state and speed change. In operation, and during the starting mode, the input shaft 59 is rotated by an unloaded ground wheel 52, rotation of which represents the true ground speed of the harvester. The control side gear 61 is therefore rotated and this rotation is transmitted via idler gears 63 to rotate the output side control gear 62. This gear 62 rotates the output shaft 54 coupled to the flow control valve 53. Rotation of the shaft 54 opens the flow control valve 53 and hydraulic oil under pressure from the pump 50 is metered to the hydraulic motor 30a, coupled to the conveyor 26, via line 67.

Because hydraulic motors 30a and 55 are piped in series via line 68, when motor 30a rotates, motor 55 will rotate instantaneously with it at the same speed or a ratio depending on the displacement of the two motors.

Rotation of motor 55 rotates the input shaft 56 and spider pinion 64 which in turn rotates the spider gear 58 and the spider 60 together with the shaft 60a and the idler gears 63. When the idler gears 63 and input side control gear 61 rotate at the same speed, output side control gear 62 remains stationary, therefore the hydraulic flow control valve 53 will remain in the initial, set, position. The unit is now operating in the steady state mode.

Should the speed of input shaft 59 measuring true ground speeds of the harvester, vary for some reason, for example either because of slippage of a wheel 47 of the harvester or because of increase or decrease of the speed of the harvester 100 by the driver, in relation to the speed of the motor 55 output side control gear 62 will either rotate clockwise or anti-clockwise and speed up or slow down motors 30a and 55 instantaneously because the flow control valve 53 responds instantly to rotation of the shaft 54. As this change is instantaneous, the input shaft 59 and motor 55 remain constantly matched in speed (or at a consistent desired ratio dependent on the motor displacement and the internal gearing between the control side gear 61, idler gears 63 and spider pinion 64). In this way, the unit provides a constant instantaneous speed matching betwen two objects. Stated in another way any difference between the two signals represented by the speeds of the input shaft 59 and the shaft 54 introduced into the comparator device 51 offsets the synchronising control valve 53, and the difference appears as an error or difference signal in the line 67 to the hydraulic catcher conveyor motor 30a that determines the linear speed of the catcher conveyors 26. There is a coupling 69 from the motor 30a to the conveyor drive shaft. Whenever an error or difference signal output 54 from the comparator device 51 is present it corrects the speed of the drive motor 30a for the catcher conveyors 26, and the signal input represented by the shaft 59 simultaneously brings the follow-up motor 55 to the aforesaid corrected speed. The linear speed of both catcher conveyors 26 is thus quickly increased or decreased (as the case may be) until the error or difference signal in line 67 to the catcher conveyor drive motor 30a becomes zero. The synchronizing control valve or controller 53 will now have assumed a new fixed or steady state position, which position drives the motors 30a and 55 at a speed which represents the true harvester ground speed S. The upper or crop catching reaches of the catcher conveyors 26 will now be running rearwardly at a new linear speed S relative to the harvester frame and this new speed will equal the true ground speed S of the harvester. In other words the catching reaches of the catcher conveyors are always automatically maintained stationary relative to the ground, even though the harvester ground speed changes due to slippage of the driving ground wheels 47 or because of changes in harvester speed made by the operator.

In the preferred embodiment, the synchronising control valve 53 receives hydraulic fluid from the pump 50 by a line 70.

Conventional reservoir and sump systems for the hydraulic fluid are shown schematically in Figure 17. The synchronising valve 53 is a variable flow control valve such as a valve Model No. 2F86, manufactured by Fluid Controls Inc., of 8341 Tyler Boulevard, Mentor, Ohio 44060, U.S.A. The position of the valve 53 determines the flow rate of hydraulic fluid from the pump 50 through the series connected hydraulic motors 30a and 55.

This unit renders control of the catcher conveyors speed insensitive to the driven speed S of the harvester drive wheels 47 as well as to the speed of the drive train for these wheels. Neither of the latter two speeds necessarily represent true harvester ground speed S whenever a harvester driving ground wheel slips on the terrain, and hence neither the driving wheel nor the drive train speeds can be relied upon to consistently maintain the crop catcher reaches of the catcher conveyors at zero speed relative to the ground.

In addition to the zero ground speed feature, the conveyors 26 close the centre space 62 of the harvester (normally about 18" in conventional straddle harvesters).

This is achieved by the trays 32 being urged to the centre line of the harvester by their springs 42 as they start their conveying run 28 which is an upper reach in Figure 8 or a lower reach in Figure 16. This is gradually accomplished as their cam followers 33, which may be in the form of bosses, lugs or rollers suitably of nylon, travel along the inclined forward part 44 of the cam 43 which is angled to an optimum angle, which may be adjusted. The cam followers 33 are moved out to their maximum as they move along the straight portion 45. The spring 42 urges the tray carrier 36 into engagement with the carrier 40 for the cam follower 33, which carrier 40 thus acts as a stop for the trays with the spring 42 only a slight tension which assists in decreasing risk of failure of the spring. The tubes 37 of the tray carrier have flared mouths 37a into which the carrier tubes enter.

The right hand and left hand conveyor trays are arranged so that they meet at the centre line of the harvester, as shown at 'A' and 'B' in Figure 10. The harvested berries can run down inclined side screens (see Figure 1) of the harvester into the trays, any gap being closed by a sealing device in the form of a nylon brush which extends along the harvesting length of the harvester.

When the harvester approaches a plant or another obstruction such as a concrete post (see 24 in Figure 6), the trays move only as far as that obstruction, because in effect the conveyors are stationary with respect to the obstruction owing to the zero ground speed of the conveyors relative to the ground, as previously described. The trays are held lightly against the obstruction by the springs 42 so that any gap is minimised (by the resilient action of the springs). The springs 42 are under a greater tension in these positions than when they are in the 'A' or 'B' position. The trays 32 are retracted for the return run when the cam followers 33 engage the part 46 of the drum 43.

A part 44a (Figure 10) of the cam 43 (at the fore end of the harvester) is removable or can be moved as by sliding to a position where it is not struck by the cam followers.

The trays are thus not moved outwardly to the centre line of the harvester. This may be necessary in certain circumstances for example where the whole of the centre gap 62 is filled by large mature bushes to be harvested.

It will be understood that effective zero ground speed of the first embodiment of conveyor may be achieved using the speed sensing control unit already described. It will also be understood that the speed sensing control or synchronising unit could be used for matching the speed of any two objects other than the relative zero velocity of a harvester conveyor and the ground.

The trays 5, 32 may be made of any suitable material, for example steel, or plastics, or aluminium.

Referring now to Figure 18, the harvester 100 shown schematically therein has a main frame 101 mounting a pair or pairs of crop catching conveyors 102. The or each conveyor 102 is mounted by means for independent vertical adjustment for different catching heights. The means for independent vertical adjustment is, in the embodiment illustrated, in the form of fore and aft hydraulic piston and cylinder units 103 connecting the conveyors to the main frame 101. Thus by adjustment of the height of a conveyor, effectively a series of heights can be achieved with one conveyor.

It will be understood that the harvester described may be of the kind which has shakers which have tines which engage the bush or vine and shake it vigorously without destroying it. Such a harvester is shown and described in the specification of my British Patent No. 1 390 495 or in copending Application No. 20335/76 (Serial No.

1 578 926).

It will also be understood that the embodiments of conveyor shown and described herein with reference to the drawings are only examples of the invention, which can be modified in several ways.

For example, the conveyors may be mounted so that they can swing laterally of the fore and aft direction of the harvester so that the conveyors have a self-levelling effect on uneven terrain. Also, the rubber spring 10 or the coil spring 42 could be replaced by a pneumatic or hydraulic dashpot, or other suitable device. Also, the trays may be so mounted on means which allows their inboard ends to tilt downwardly when they have moved transversely so that fruit from low branches can be caught, e.g. at substantially ground level.

In every embodiment, the conveyors cover substantially the entire central gap of the harvester so that substantially all the harvested fruit can be collected and may also catch any juice expelled from the fruit during harvesting. Furthermore, in broad terms the trays or troughs are constrained at all points along the predetermined path of the conveyor to maintain, even at direction changes, an orientation relative to the support Inks of any given tray which is substantially constant. In narrower terms the trays will be in a substantially horizontal plane while in the upper run, whether or not in a fruit catching portion of the run, will be inverted but in a horizontal plane in the return run and will progressively change orientation at each end.

Where the conveyor has an inclined position the trays will take on a substantially matching orientation.

WHAT WE CLAIM IS:- 1. An endless conveyor comprising individual conveying elements together defining a conveying reach and at least part of each of which elements is movable or compressible in a direction laterally of the conveying d

Claims

**WARNING** start of CLMS field may overlap end of DESC **. far as that obstruction, because in effect the conveyors are stationary with respect to the obstruction owing to the zero ground speed of the conveyors relative to the ground, as previously described. The trays are held lightly against the obstruction by the springs 42 so that any gap is minimised (by the resilient action of the springs). The springs 42 are under a greater tension in these positions than when they are in the 'A' or 'B' position. The trays 32 are retracted for the return run when the cam followers 33 engage the part 46 of the drum 43. A part 44a (Figure 10) of the cam 43 (at the fore end of the harvester) is removable or can be moved as by sliding to a position where it is not struck by the cam followers. The trays are thus not moved outwardly to the centre line of the harvester. This may be necessary in certain circumstances for example where the whole of the centre gap 62 is filled by large mature bushes to be harvested. It will be understood that effective zero ground speed of the first embodiment of conveyor may be achieved using the speed sensing control unit already described. It will also be understood that the speed sensing control or synchronising unit could be used for matching the speed of any two objects other than the relative zero velocity of a harvester conveyor and the ground. The trays 5, 32 may be made of any suitable material, for example steel, or plastics, or aluminium. Referring now to Figure 18, the harvester 100 shown schematically therein has a main frame 101 mounting a pair or pairs of crop catching conveyors 102. The or each conveyor 102 is mounted by means for independent vertical adjustment for different catching heights. The means for independent vertical adjustment is, in the embodiment illustrated, in the form of fore and aft hydraulic piston and cylinder units 103 connecting the conveyors to the main frame 101. Thus by adjustment of the height of a conveyor, effectively a series of heights can be achieved with one conveyor. It will be understood that the harvester described may be of the kind which has shakers which have tines which engage the bush or vine and shake it vigorously without destroying it. Such a harvester is shown and described in the specification of my British Patent No. 1 390 495 or in copending Application No. 20335/76 (Serial No.

1 578 926).

WHAT WE CLAIM IS:- 1. An endless conveyor comprising individual conveying elements together defining a conveying reach and at least part of each of which elements is movable or compressible in a direction laterally of the conveying drection of the conveying reach, while the orientation of said part of each element is maintained substantially constant in relation to the direction of motion of the conveyor at each corresponding point along and throughout its path of travel.

2. For a harvesting machine, for harvesting tree, bush, cane- or vine-borne crops such as currants, berries or grapes, having a frame which can be moved along a row of standing trees, bushes, canes or vines and which supports a shaker or beater device to release crop from the trees, bushes or vines, an endless conveyor having a conveying reach drivable in a conveying direction and having individual conveying elements at least a part of each of which element is movable laterally of the conveyng direction of the said conveying reach, the elements being shaped and disposed to catch crop released by the shaker or beater device and means mounting the said part of each element constraining the part to maintain a substantially constant orientation in relation to the directon of motion of the conveyor at each corresponding point along and

throughout the path of travel of that point.

3. An endless conveyor according to Claim 1 or Claim 2, comprising a plurality of carriers each of which slidably supports an individual said conveying element for said lateral movement.

4. An endless conveyor according to Claim 3, wherein the carriers are secured between two spaced endless drive members.

5. An endless conveyor according to Claim 4, wherein the carriers each comprise two parallel, spaced, rods.

6. An endless conveyor according to any of Claims 3 to 5, including means for guiding each individual said element in the lateral direction of the conveyor and resilient means operative between each individual conveyor element and its carrier laterally biasing that element.

7. An endless conveyor according to Claim 6, wherein the guiding means comprises a cam which co-operates with the resilient means during movement in the conveying direction.

8. An endless conveyor according to Claim 7, wherein the resilient means comprises a spring operative between a seating on the carrier for the element and separate cam follower means also mounted on the carrier.

9. An endless conveyor according to Claim 8, wherein the cam follower includes a boss which depends from the seating on the carrier so that it can engage and be guided by the cam.

10. An endless conveyor according to Claim 9, wherein the cam comprises a lead-in porton inclined to the conveying direction, a straight portion extending parallel to the conveying direction and a lead-out portion which is inclined - to the conveying direction.

11. An endless conveyor according to Claim 10, wherein the angles of inclination of the lead-in and lead-out portions are different.

12. An endless conveyor according to Claim 10 or Claim 11, wherein the angle of the lead-in portion is at a greater inclination with respect to the conveying direction than the lead-out portion.

13. An endless conveyor according to Claim 12, wherein the respective angles of inclination of the lead-in and lead-out portions are 45" and 3710.

14. An endless conveyor according to any one of Claims 10 to 13, wherein the leadout portion comprises a pair of parallel spaced rails between which the cam follower can pass for retracting the conveyor elements from an extended position.

15. An endless conveyor according to Claim 14, wherein the cam follower comprises a stop defining the extended, lateral, position of the conveyor elements.

16. An endless conveyor according to any preceding claim, which is arranged with the conveying reach and a return reach disposed horizontally one above the other, the upper reach being the conveying reach and the lower reach being the return reach.

17. An endless conveyor according to any preceding claim, in which each conveying element comprises a tray- or troughlike element which has a lip along one edge which overlaps an edge of an adjacent element of the conveyor.

18. A harvester for harvesting tree-, bush-, cane- or vine-borne crops, comprising a frame which can be moved along a row of standing trees, bushes, canes or vines and which supports a shaker or beater device to release the crop, an endless conveyor according to any preceding claim extending in the longitudinal direction of the harvesting machine, and means for driving the conveyor so that its conveying direction is opposite to the direction of movement of the harvesting machine over the ground and the linear speed of the conveying reach of the conveyor relative to the ground is zero.

19. A harvester according to Claim 18, which is a straddle harvesting machine which has two said endless conveyors extending along opposite sides of a central passage through the harvesting machine whereby the individual said conveyor elements can meet at or near the longitudinal centre line of the machine in the conveying reach to close the central passage for catching and conveying harvested crop.

20. A harvester according to Claim 18 or Claim 19, wherein the conveyor drive means comprises a comparator device connected to receive a control speed input from ground speed sensor means and a separate follow-up input from a motor coupled to the conveyor and having an output which changes with change in the ratio between the two input speeds and which is coupled with a control synchronizer device for controlling the output of the conveyor motor for varying the speed of the conveyor so that the desired relative zero ground speed of the conveyor is maintained.

21. An endless conveyor comprising flexible drive means movable along a predetermined endless path, conveying elements mounted on the drive means at least a part of each of which elements is displaceable laterally with respect to the direction of motion of the drive means, and means mounting the conveying elements on the drive means such that throughout the predetermined endless path the orientation of each said part of each said conveyor element remains substantially constant relative to the part of the drive means mounting the said element.

22. An endless conveyor according to claim 21, wherein the conveyor element mounting means includes elongate guide members for each conveyor element, said guide members being spaced apart in the direction of motion of the conveyor.

23. An endless conveyor according to claim 22 comprising for each conveyor element, a carrier slidable on the guide members of that element.

24. An endless conveyor according to any one of claims 21 to 23 wherein lateral displacement of the parts of the conveyor elements is effected by cam means operative in conjunction with means biasing the conveyor elements in one lateral direction.

25. An endless conveyor, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

26. A harvester for harvesting tree, bush, cane or vine crop, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.