BALE WRAPPING APPARATUS

Abstract: A mobile bale wrapper apparatus (10) which is operative (a) to pick up the bale, (b) to wrap the bale with stretchable plastics film wrapping and (c) to discharge the wrapped bale from the apparatus, and which comprises: a frame (13); a bale-handling device (16) comprising a pair of elongate lifting devices laterally spaced apart from each other with respect to the path of travel and engageable with opposed sides (27) of the bale to lift the bale to the bale-wrapping position, and thereafter to apply a tumbling type of rotation to the bale about a substantially horizontal axis extending generally parallel to the path of travel; means (20) for holding a supply reel of stretchable plastics film for wrapping the bale; means (21) for causing relative angular movement between the supply reel and the bale about at least one substantially vertical axis (22), and means (19) operative to discharge the wrapped bale from the apparatus.

Description: BALE WRAPPING APPARATUS This invention relates to a bale wrapping apparatus of the type which is capable of engaging a bale lying on the ground in the path of travel of the apparatus and which is operative (i) to pick—up the bale, (ii) to wrap the bale with stretchable plastics film wrapping and (iii) to discharge the wrapped bale from the apparatus. A bale wrapping apparatus of the above general type is disclosed in more detail in International publication No W94/17653 and to which reference is made. Some of the preferred embodiments of W094/17653 will be described below with reference to Figures 1 to 5 of the accompanying drawings, and to form a background to the improved bale handling device, and improved drive mechanism, to be incorporated in a bale wrapping apparatus according to the present invention. Figure 1 is a plan view of a bale wrapper apparatus, showing it occupying an off-set position towed behind a tractor; Figure 2 is a side view of the apparatus shown in Figure 1 ; Figure 3 is an end view of the apparatus shown in Figures 1 and 2; Figure 4 is a rear view of the apparatus showing a bale lifting device in an inoperative position prior to engagement with a bale lying on the ground; and, Figure 5 is a view, similar to Figure 4, showing an initial stage in a bale-lifting operation. Referring first to Figures 1 to 3 of the drawings, there is shown a bale wrapper apparatus which is designated generally by reference 10 and which is being towed in the direction of arrow X in Figure 1 behind a propelling vehicle in the form of tractor 11 in a laterally off-set position so that the tractor 11 can run alongside a line of bales deposited in a field, of which one is shown by dotted outline 12. It can be seen from Figure 1 that the apparatus 10 is readily liried-up with the bale 12, and is able to receive the bale, lift it, apply stretchable plastics film wrapping around it, and then rearwardly discharge the wrapped -hale during forward movement of the tractor 11 and apparatus 10 towards the next bale in the row. The apparatus 10 comprises a frame designated generally by reference 13, coupling means in the form of a tow bar.14 attached to and projecting forwardly of the frame 13 to enable the apparatus 10 to be towed behind the tractor 11 , and an arch structure 15 which forms part of the frame 13 and which faces in the intended direction of travel and which is of sufficient size to allow bale 12 lying on the ground to pass through the arch 15 when the apparatus 10 is moved forwardly. In the illustrated embodiment, the arch 15 is located at the rear end of the frame 13 of the apparatus, and therefore it will be the wrapped bale which is discharged through the arch 15 after completion of the wrapping operation. Figure 3 is a rear view of the apparatus, and shows how different shapes of bale 12 can be readily received by the apparatus on.a through—flow basis, with bale 12 being shown taking up a number of different rectangular cross section shapes, and also a cylindrical shape. A 2—part bale lifting device designated generally by reference 160 (see Figure 3) is mounted on the frame 13 and is operative to lift the bale 12, after it has been received by the apparatus, to take-up a raised bale-wrapping position. The lifting device 160 comprises a pair of lifting roller assemblies 16 (see Figure 1) laterally spaced from each other, as shown in Figure 3, to allow bale 12 to be received between them, and each assembly 16 is operative to engage at least an adjacent side and / or underside of the bale 12 and to lift the bale to the bale-wrapping position. In the case of a rectangular cross section bale, each lifting assembly 16 will be engageable with the adjacent substantially vertical opposed side of the bale. Each lifting assembly 16 comprises mounting plates 17 pivotally mounted on the end of a support arm 18, and which can be pivoted inwardly and outwardly via the arm 18 between positions of different spacings apart from each other of the assemblies 16 to allow different widths of bale to be handled. Each pair of plates 17 carries two rollers 19 which extend generally parallel to the direction of travel, and which occupy a bale-lifting position as shown in Figure 3 in which one roller 19 is above the other, and upon the application of drive to the rollers, the bale can be lifted by frictional contact between the rollers and the sides of the bale. Figure 4 is an enlarged view of the roller assemblies and associated components, and Figure 5 is a similar view showing an initial stage in the lifting operation. As will be described in more detail with reference to the subsequent figures of drawings, the bale lifting assemblies 16 are also capable of constituting means for rotating the bale about a substantially horizontal axis which extends generally parallel to the direction of travel after the bale has been lifted to the bale-wrapping position, and this rotation of the bale, in conjunction with the provision of means to effect relative rotation between a film supply reel and the bale about a substantially vertical axis enables film to be withdrawn from the reel to apply successive overlapping windings to the bale in order to wrap it. In the illustrated embodiment, the supply reel support unit, designated by reference 20, is mounted on the end of a rotary support arm 21 which is rotatable about substantially vertical axis 22 via a rotary mounting 23 at its inboard end, whereby the unit 20 can be caused to carry out a circular orbital path of movement around the bale 12 while the latter is being rotated about generally horizontal axis 24. However, it is not essential for the reel support unit 20 to move along a circular path, and there may be situations in which it is more preferable for the unit to move along a closed path or loop which is non-circular e.g. elliptical, in which case the unit 20 may be arranged to carry out angular movement about more than one vertical axis. The frame 13 of the apparatus is supported by a set of rear wheels 25, and can be pulled forwardly in the off-set position shown in Figure 1 , in order to carry out handling, wrapping and discharge of the bale.12, but apparatus 10 can be pivoted to a transport position directly behind the tractor 11. Only a single support unit 20 for a film dispenser reel is shown in Figures 1 to 3, and this support unit may be of any known types currently in use of "satellite" type film dispenser arrangements. The support unit 20 may incorporate any suitable pre-stretcher mechanism e.g. of the type disclosed in EP 0291483. However, if desired, a double arm may be provided, having support unit 20 at each end, so that double film wrapping can take place simultaneously. Alternatively, a further support arm and respective film reel support unit may be provided. Figure 4 shows the two lifting roller assemblies 16 of device 160 pivoted to the most extreme laterally separated position, but they can be moved towards each other under the action of a ram 26 until the rollers 19 come into engagement with the opposed substantially vertical sides 27 of bale 12, ready to carry out a bale-lifting operation. The rollers 19 of the left hand assembly 17 will both be rotated in anti¬ clockwise direction, whereas the rollers 19 of the right hand assembly will be rotated in a clockwise direction to lift the bale. Once the rollers 19 have raised the bale 12 to the bale-wrapping position, the assemblies 16 can be caused to pivot about the pivots 28 at the lower end of arms 18 until they take—up a horizontal position below the bale, ready to apply rotary movement to the bale 12 about generally horizontal axis 24. When they have reached this position, all of the rollers 19 will be driven in the same direction which will be clockwise in order to rotate the bale in an anti—clockwise direction. The driving of the rollers.19, and their direction of rotation may be programmed into an automatic control system which controls the operation of the bale wrapper. The present invention provides a bale wrapper apparatus having an improved bale handling device, and drive mechanism therefore, as defined below. Accordingly, the present invention provides a mobile bale wrapper apparatus which is capable of engaging a bale lying on the ground in the path of travel of the apparatus and which is operative (a) to pick-up the bale, (b) to wrap the bale with stretchable plastics film wrapping and (c) to discharge the wrapped bale from the apparatus, and which comprises: a frame; a bale—handling device mounted on the frame and operative to lift a bale lying on the ground to a bale wrapping position, said device comprising a pair of elongate lifting devices laterally spaced apart from each other with respect to the path of travel and engageable with opposed sides of the bale to lift the bale to the bale wrapping position, and thereafter to apply a tumbling type of rotation to the bale about a substantially horizontal axis extending generally parallel to the path of travel; means for holding a supply reel of stretchable plastics film for wrapping the bale; means for causing relative angular movement between the supply reel and the bale about at least one substantially vertical axis, while the bale is carrying out tumbling rotation about said substantially horizontal axis, whereby film can be withdrawn from the reel to apply successive overlapping windings to the bale in order to wrap the latter; and means operative to discharge the wrapped bale from the apparatus: in which each elongate lifting device comprises: a pair of rollers which are spaced apart from each other and which extend parallel to each other and in the direction of the path of travel of the apparatus; first and second roller carriers rotatably mounting the rollers at each end thereof, said carriers being pivotable about a common pivot axis which extends parallel to the axes of the rollers in order to adjust the position of the rollers laterally relative to the bale; a drive motor coupled drivingly with said rolle.rs and operable (1) to rotate the rollers in order to lift the bale from the ground to the bale-wrapping position and (2) thereafter to rotate the rollers so as to apply a tumbling type of rotation to the bale about said generally horizontal axis so that bale wrapping can take place; and in which the drive motor is mounted on one of said roller carriers so as to be movable with said one carrier during pivotable movement of the carrier about said common pivotable axis, said motor being laterally spaced from said common pivotable axis. The roller carriers therefore are capable of carrying out pivotable adjusting movement about the common pivot axis (to vary the positions of the rollers relative to the bale as is necessary to carry out bale-lifting, followed by bale rotation), and simple pivotable mounting assemblies may be used e.g. simple roller bearing and stub-shaft assemblies. In addition, a simple drive train is provided to apply necessary rotation to the rollers, which may comprise any suitable relatively lightweight motor mounted on one of the roller carriers in laterally off—set spacing from the common pivot axis, and which is coupled with the rollers in any convenient way e.g. via chains and sprockets. Conveniently, the motor is a hydraulic motor, though evidently other forms of motor may be used e.g. electric motors. By isolating the drive train from the common pivotable axis, each lifting device can readily carry out pivotable adjustment about its pivot axis (to vary the roller positions relative to the bale), and in particular when bale wrapping is taking place, the tumbling rotation imparted to the bale by the rollers exerts a feedback. to the carriers whereby they can automatically adjust themselves about the pivot axis to improve the way in which each roller pair engages the bale sides and edges. Evidently, by applying a tumbling type of rotation to a square or rectangular shaped bale, there will be a tendency for the instantaneous angular speed of rotation applied to the bale to vary during each complete, revolution. However, by allowing the carriers to pivot relatively freely about the pivot axis, this allows the roller pair to adjust themselves (relative to the varying bale profile presented to them, and especially when a bale edge engages between them) to provide a more uniform rate of rotation. This is an important and preferred objective of the invention, since excessive variation in instantaneous speed of rotation of the bale would result in variable overlap between successive windings of film wrapping. Variable overlap is undesirable, since too great an overlap would involve excessive consumption of film material, whereas insufficient, or even no overlap would allow atmospheric communication with the contents of the wrapped bale, with adverse effect on its quality, and especially when grass is being wrapped to form silage. To allow easy entry into the apparatus of a bale lying on the ground, preferably an arch structure forms part of the frame of the apparatus and which faces in the direction of the intended path of travel, such arch structure being of such a size and shape as to allow the bale lying on the ground to pass freely through the arch structure. The arch structure is preferably positioned at the forward end of the apparatus, so that the bale lying on the ground must first pass through the arch structure, before being received by the bale handling device for subsequent lifting, bale wrapping and then discharge. Preferably, said one carrier on which the drive train is mounted (to apply rotation to the rollers to lift and then to rotate the bale), is located at the end of the rollers remote from the arch structure. . In a preferred embodiment of the invention, the motor transmits drive to each roller by an endless chain and sprocket drive mechanism, and in which a sprocket transmits rotary input drive to the respective roller via an eccentric drive to an externally toothed internal gear which orbits within an internally toothed external gear. By means__of the orbiting movement of the internal gear, and relative arrangements of the internal and external teeth, a substantial speed reduction i.e. substantial step-down transmission ratio may be achieved. By way of example only, the external gear may have 21 internal teeth, whereas the internal gear has 19 external teeth, and with the centre of the internal gear being driven, via an eccentric drive input, to orbit around a circle of very small diameter, only a small number of the external teeth of the internal gear engage or mesh with a similarly small number of the internal teeth of the external gear at any one time, and a step down transmission ratio of 10.5:1 can be obtained. The rotary sprocket input drive to the internal gear may comprise an eccentric mounted on a projecting stubshaft of the roller, and which eccentric is rotatable within the internal gear, and thereby applies orbiting movement of the central axis of the internal gear about the axis of the stubshaft. The speed reduction to the roller therefore results in a step-up of the torque which is applied, which assists in application of necessary gripping force between the roller and the bale periphery. Said one carrier on which the drive train is mounted may comprise a simple mounting bracket or plate, in which the projecting stubshaft ends of the rollers can be readily mounted, and the plate also may have a suitable bearing to receive the end of a pivot shaft forming the common pivot axis for the carriers. A simple control mechanism may be provided to control the orbiting movement of the internal gear, and this may comprise a respective control or slide plate pivoted to each internal gear and slidably mounted on the mounting plate. A pin and slot interconnection may be provided to allow limited sliding movement of the control plate while the internal gear carries out its eccentrically driven orbiting movement. The control plates may cooperate with each other, to work in conjunction with each other, and one control plate may have a projecting pin, and the other control plate have a matching slot within which the pin can slide, and this provides a simple mechanical device capable of controlling the orbiting movement of the two internal gears. Preferred embodiments of the present invention will now be described in detail, by way of example only, with reference to Figures 6 to 11 of the accompanying drawings, in which: Figure 6 is a schematic end view of a first embodiment of novel bale handling device according to the invention, which is capable of use in a bale wrapper apparatus of the type disclosed in W094/17653, and a novel drive transmission therefore; Figure 7 is a detail schematic illustration of part of the drive train to one of the pair of rollers of the handling device shown in Figure 6; Figure 8 is an end view, to an enlarged scale, showing part of the drive train to the rollers in more detail; Figure 9 is a detail view of an eccentric drive train input to one of the rollers; Figure 10 illustrates a drive motor, to an enlarged scale, which provides drive input to rotate the rollers; and. Figure 11 is a schematic end view of a second embodiment of the invention. Referring now to the drawings, description will now be made of the first embodiment shown in Figures 6 to 10. This shows an improved bale handling device, and in particular shows in more detail a modified means of assembly of the rollers 19 shown in Figures 1 to 5, and an improved means of applying drive to the rollers 19. Figure 6 is an end view of the mounting of the rear ends of rollers 19 at the rear end of the machine. Mounting or carrier plates rotatably mount the rollers 19 at each end thereof, although the mounting at the forward ends of the rollers 19 is not shown in the drawings. A mounting or carrier plate 50 forms a carrier for the .rear ends of the pair of rollers 19, and rotatably mounts stubshafts 51 projecting from the rear ends of the rollers 19. Carrier plate 50 (and also the forward carrier which rotatably mounts the forward ends of rollers 19) are pivotably mounted on a common pivot axis 52 which is provided by a rigid mounting tube 54 running the length of the apparatus, and in the case of carrier plate 50 comprises a boss 53 projecting from the end of the tube 54. Pivot axis 52 extends parallel to the axes 55 of the rollers 19, and the carriers are pivotable about axis 52 in order to adjust the positions of the rollers 19 laterally * relative to the bale which is to be lifted, and then wrapped. A drive motor 56, which preferably is a hydraulic motor, is coupled drivingly with the rollers 19 and is operable (a) to rotate the rollers 19 in order to lift the bale from the ground to the bale wrapping position and (b) thereafter to rotate the rollers 19 so as to apply a tumbling type of rotation to the bale about a generally horizontal axis so that bale wrapping can take place. The drive motor 56 is mounted on the rear roller carrier 50, in the illustrated embodiment, but this is merely a preferred arrangement. It is therefore capable of moving with carrier 50 during pivotable movement of the carrier about the common pivotable axis 52, and it will be noted, particularly from Figure 6, that the motor 56 is laterally spaced a considerable distance from the common pivotable axis 52. The roller carriers (50) therefore are capable of carrying out pivotable adjusting movement about the common pivot axis 52 (to vary the positions of the rollers 19 relative to the bale as is necessary to carry out bale- lifting, followed by bale rotation) . Therefore, simple pivotable mounting assemblies are sufficient, namely simple roller bearing and stubshaft assemblies, in order to mount the rollers on the carrier plates. Further, a simple drive train is provided to apply necessary rotation to the rollers 19, in that a relatively lightweight motor (56) is mounted on carrier plate 50, and in the illustrated embodiment is coupled with the rollers 19 via chains 57 and sprockets 58. Therefore, the drive train to operate the rollers 19 is isolated from the common pivotable axis 52, and each lifting device / bale rotation device (rollers 19 and roller carrier 50) can readily carry out pivotable adjustment about pivot axis 52 (to vary the roller positions relative to the bale), and in particular when bale wrapping is taking place, so that the tumbling rotation imparted to the bale by the rollers 19 exerts a feedback to the carriers (50) whereby they can automatically adjust themselves about the pivot axis 52 (if necessary against spring biasing not shown) to improve the way in which each pair of rollers 19 engages the bale sides and edges. The relative freedom for the carriers 50 to pivot about common pivot axis 52 allows the pair of rollers 19 to adjust themselves to the varying bale profile presented to them, and especially when a bale edge engages between them, thereby to provide a reasonably uniform rate of rotation. Conveniently, the arch structure of the apparatus (described in more detail with reference to Figures 1 . to 5) is provided at the forward end of the apparatus, so that the bale lying on the ground must first pass through the arch structure, before being received by the bale handling device for subsequent lifting, bale wrapping and then discharge. The carrier plate 50 on which the drive train is mounted (to apply rotation to the rollers 19) is therefore located at the end of the rollers 19 remote from the arch structure. The manner by which the motor 56 transmits drive to each roller 19 will now be described in more detail, and effectively rotary input drive to each roller 19, via sprocket 58, is transmitted first to an eccentric drive 59 which applies drive to an externally toothed internal gear 60 which orbits within an internally toothed external gear 61. By means of the orbiting movement of internal gear 61 , and the relative arrangements of the only partly intejrmeshing internal and external teeth of gears 60 and 61 , a substantial speed reduction i.e. substantial step-down transmission ratio is achieved. In the illustrated arrangement, external gear 61 has 21 internal teeth, whereas internal gear 60 has 19 external teeth. Furthermore, the central axis of the internal gear 60, shown by reference 62, carries out orbital movement along a circle of small radius, as shown by dotted outline 63, under the application of drive transmitted thereto by the eccentric driving member 59. The orbital movement of the internal gear 60 results in instantaneous meshing between the teeth of internal gear 60 and of external gear 61 along only a very small part of the outer periphery of internal gear 60 and internal periphery of outer gear 61 , and Figure 6 shows the intermeshing between the gears when the internal gear 60 has reached an extreme position to the right with respect to axis 55, and the arrangement is such that 10.5 revolutions of internal gear 60 take place for each single rotation of outer gear 61. This speed reduction therefore results in a step-up of the torque which is applied to rollers 19, which assists in application of necessary gripping force between the rollers and the periphery of the bale. A control mechanism is provided to control the orbiting movement of the internal gear 60, and this comprises a pair of control or slide plates 64, each associated with a respective internal gear 60, and pivoted thereto via pivots 65. The slide plates 64 are slidable relative to each other, by means of pin and slot connections, comprising a pin 66 at one end of each plate, and a receiving slot 67 in the other plate. Each slot 67 is of sufficient length to allow slidable movement of pin 66 therein, to accommodate orbital movement of the axis 62 of internal gear 60 around small circular orbit 63. Figures 6 to 10 illustrate one particularly preferred arrangement of drive motor (56) which is off-set relative to common pivot axis 52 by a substantial distance, and with axis 52 serving solely to form a pivot point about which the carrier plates 50 and the assembly of rollers 19 therewith can pivot automatically to provide the most effective engagement of the rollers 19 with the varying profile presented thereto of the rotating bale. However, other arrangements of laterally off—set drive motor may be provided i.e. laterally off—set from a common pivotable axis, as shown, by way of example, in Figure 11 of the drawings. Corresponding parts are designated by the same reference numerals, and in this embodiment a mounting plate 68 carries the rollers 19, and is mounted for pivotable movement about a longitudinally extending pivot axis 69, which also serves as the pivot axis for any suitable roller carrier (not shown) at the forward end of the rollers. A hydraulic motor 70 is mounted on mounting plate 68, for pivoting movement therewith, and drives an output shaft 71 which extends perpendicular to axis 69, and on which is mounted worm gears 72 which make driving engagement with the teeth 73 of worm wheels (not shown in detail) mounted co-axially on the ends of projecting drive shaft stubs on rollers 19. Apart from having an alternative arrangement of laterally off—set drive train, the operation of roller carrier assembly (68, 19) is generally the same as the embodiment described with reference to Figures 6 to 10. The laterally off-set arrangement of drive trains, and drive motors, i.e. laterally spaced and isolated from the common pivot axis (52, 69) is a significant technical advantage, as compared with possible mounting of a rotary drive output having an axis coincident with the common pivot axis. Thus, an arrangement of drive means on the pivot axis would inevitably generate substantial torque reaction in service, which would interfere with desired relatively free pivotable movement of the roller carrier assemblies about the common pivot axis, as the bale carries out its tumbling rotation. This free pivoting action in the preferred embodiment of the invention, enables the pair of rollers to be presented in the most advantageous attitude to the__yarying bale profile as it rotates. Furthermore, it has been found that, at least with the embodiment of Figures 6 to 10, a relatively low power motor is quite sufficient, and in addition relatively low duty chains and sprockets are required in order to transmit the necessary drive to rotate the rollers.

Claims: CLAIMS 1. A mobile bale wrapper apparatus (10) which is capable of engaging a bale (12) lying on the ground in the path of travel X of the apparatus and which is operative (a) to pick-up the bale, (b) to wrap the bale with stretchable plastics film wrapping and (c) to discharge the wrapped bale from the apparatus, and which comprises: a frame (13); a bale-handling device (16) mounted on the frame (13) and operative to lift a bale lying on the ground to a bale- wrapping position, said device comprising a pair of elongate lifting devices laterally spaced apart from each other with respect to the path of travel and engageable with opposed sides (27) of the bale to lift the bale to the bale-wrapping position, and thereafter to apply a tumbling type of rotation to the bale about a substantially horizontal axis extending generally parallel to the path of travel; means (20) for holding a supply reel of stretchable plastics film for wrapping the bale; means (21) for causing relative angular movement between the supply reel and the bale about at least one substantially vertical axis (22), while the bale is carrying out tumbling rotation about said substantially horizontal axis, whereby film can be withdrawn from the reel to apply successive overlapping windings to the bale in order to wrap the latter; and, means (19) operative to discharge the wrapped bale from the apparatus: in which each elongate lifting device comprises: a pair of rollers (19) which are spaced apart from each other and which extend parallel to each other and in the direction of the path of travel X of the apparatus; first and second roller carriers (50) rotatably mounting the rollers (19) at each end thereof, said carriers being pivotable about a common pivot axis (52, 69) which extends parallel to the axes (51) of the rollers (19) in order to adjust the position of the rollers (19) laterally relative to the bale; a drive motor (56) coupled drivingly with said rollers (19) and operable (a) to rotate the rollers (19) in order to lift the bale from the ground to the bale-wrapping position and (b) thereafter to rotate the rollers (19) so as to apply a tumbling type of rotation to the bale about said generally horizontal axis so that bale wrapping can take place; and in which the drive motor (56) is mounted on one of said roller carriers (50) so as to be movable with said one carrier (50) during pivotable movement of the carrier about said common pivotable axis (52, 69), said motor (56) being laterally spaced from said common pivotable axis. 2. A bale wrapper apparatus according to Claim 1 , in which the motor comprises a hydraulic or electric motor (56) having its drive axis extending generally parallel to said common pivotable axis (52, 69), and laterally spaced therefrom, and coupled with the rollers (19) via chains and sprockets (57, 58). 3. A bale wrapper apparatus according to Claim 1 or 2, including an arch structure (15) forming part of the frame (13) of the apparatus and facing in the direction of the intended path of travel, said arch structure being of such a size and shape as to allow the bale lying on the ground to pass freely through the arch structure. 4. A bale wrapper apparatus according to Claim 3, in which the arch structure (15) is positioned at the forward end of the apparatus, so that the bale lying on the ground must first pass through the arch structure, before being received by the bale handling device (16) for subsequent lifting, bale-wrapping and then discharge. 5. A bale wrapper apparatus according to Claim 4, in which said one roller carrier (50) on which the drive train is mounted is located at the rear end of the rollers (19) remote from said arch structure (15). 6. A bale wrapper apparatus according to any one of Claims 1 to 5, in which a rotary input drive to each roller (19) comprises an eccentric drive member (59) engageable with an externally toothed internal gear (60) which orbits around a circular path (63) of small diameter upon rotation _qf said eccentric member (59), and within an internally toothed external gear (61). 7. A bale wrapper apparatus according to Claim 6, in which the external teeth of the internal gear (60) mesh, at any one time, only with a small number of the internal teeth of the external gear (61) as the internal gear orbits around said circular path (63), whereby to provide a substantial step down transmission ratio. 8. A bale wrapper apparatus according to Claim 6 or 7, in which the orbital movement of each of said internal gears (60) is controlled by a pair of cooperating slide plates (64), each coupled with a respective one of said internal gears (60), and having slidable pin and slot interconnections (66, 67) which allows said orbital movement of the internal gears (60). 9. A bale wrapper apparatus according to Claim 1 , in which the hydraulic motor (70) is mounted on said roller carrier mounting plate (68), and has a drive shaft (71) projecting therefrom which extends substantially perpendicular to the common pivotable axis (69), and spaced laterally therefrom, and having worm gears (72) engageable with worm wheels (73) mounted on, and in driving connection with said rollers (19).

Inventors: ROYENBERG ERLING, ROYENBERG, ERLING
Applicants: KVERNELAND UNDERHAUG AS, ORR WILLIAM MCLEAN, ROYENBERG ERLING, KVERNELAND UNDERHAUG A/S, ORR, WILLIAM, MCLEAN, ROYENBERG, ERLING
Application year: 1995
Main classification: A01F15
IPC codes: A01F15