IES970546A2 - A bale wrapping machine - Google Patents

Abstract

The invention describes an apparatus for wrapping bales of fodder particularly large rectangular or square bales (9) of fodder with a strip of wrapping material and comprises a support platform (4), conveying means supported on the platform for supporting the bale (9) and rotating the bale about a substantially horizontal axis and means (20) for continuously supplying a strip of wrapping material to the bale as the bale is turned through said axis to wrap the wrapping material around the bale. The conveying means includes a conveyor belt (12) rotatable about two substantially parallel rollers (10, 11) extending transversely of the support platform and located at one end and at the opposite end respectively of the support platform (4), such that the rollers are spaced above the platform, and the conveyor belt is suspended from the rollers and has a substantial sag which defines a cradle (17) to receive the bale. The rollers are each mounted for rotation at the upper end of a respective pair of upright arms (13, 14) with at least one pair of arms (13, 14) being pivotally attached to the platform (4) such that during movement of the belt about the rollers at least one of the rollers is free to pivot relative to the other to alter the depth of the sag in the conveyor belt (12) and to improve contact of the belt with the bale during rotation of the bale. Preferably, the two pairs of arms (13, 14) are pivotally mounted to the platform (4). Cam means (50) is provided to limit the pivotal movement of one pair of arms (14) and the roller (11) carried by the arms (14). <Fig. 8>

Description

A BALE WRAPPING MACHINE OPEN TO PUBLIC INSPECTION UNDER SECTION 28 AND RULE 23 Technical Field The invention relates to a bale wrapping machine. The invention is particularly concerned with a machine for wrapping bales of silage, hay, straw and the like (hereinafter referred to as fodder) with a plastics film.

Background Art It has become conventional practice in agriculture to form fodder into cylindrical-shaped bales which are then wrapped in a plastics film. This is a particularly suitable method of manufacturing silage because the silage is kept air-tight within the wrapped bale which, typically, is wrapped with up to six plies of plastics. The cylindrically shaped bales are commonly called big round bales.

Machines for wrapping big round bales with a plastics film are described, for example, in British Patent Specifications Nos. 2191984A, 2228246A and EP 0208034A (GB 2159489B).

Bale wrapping machines of the kind described comprise a wheeled chassis which may be towed by a tractor. The chassis carries a tipping platform which, in turn, supports a turntable. The turntable is rotatable about a vertical axis. The turntable carries a pair of spaced rollers each of which rotates about a horizontal axis. An endless belt is stretched between the rollers and rotates with the rollers. In order to wrap a large round bale of fodder material with plastics film, the round bale is lifted onto the turntable by means of lifting arms. The bale rests on the endless belt. The free end of a roll of plastics film is attached to the bale and the turntable is then rotated about a generally vertical axis to cause the sheet of film to be wrapped around the bale. However, if no movement of the bale about its longitudinal axis were to occur the bale would merely 362 IR IE 970546 - 2 be wrapped with a single band having the thickness of the width of the plastics film. However, on each rotation of the turntable the endless belt is caused to move for a predetermined distance which, in turn, causes the bale to roll about its surface, i.e. about a horizontal axis. This rolling of the bale on the belt allows a new area of bale to be wrapped by the film on each rotation of the turntable, thus eventually achieving a complete covering of the bale with a substantial degree of overlap of the plastics film.

In the bale-wrapping machines described above the bale to be wrapped is mounted on a turntable which rotates about a vertical axis, and the dispenser for the roll of plastics film is fixed. It is the rotation of the bale about the vertical axis which causes the film to be unrolled from the dispenser. However, it is also known from the prior art, for example in EP-B-0110110, DE 3642513A, and GB 2193683A, for the bale to be mounted on rollers which rotate the bale only about the horizontal axis. In this arrangement there is provided a rotary support arm for the film dispenser which rotates the film dispenser, about a vertical axis, around the bale, while the bale is being turned about a horizontal axis.

More recently, there has been a tendency for farmers to use baler machines which form the fodder into large bales of a substantially rectangular or square shape. Such machines include Ford New Holland D1000, Hesston 4600, Hesston 4700, Welger Delta 4000, Mengele SB 8580, Claas Quadrant, Deutz Fahr G.P. 3.612. The bales produced by these machines are commonly referred to as big square bales. These bales may, in fact, have a cross-section which is either square or rectangular. These bales present a problem because they cannot adequately be wrapped with film using conventional big bale wrapping machines.

German Gebrauchsmuster No. G9004354.5 (Gebruder Welger GmbH & Co. KG.) discloses apparatus for wrapping bales of fodder. It is said to be an object of the invention disclosed in DE G 9004354.5 to provide apparatus which can wrap rectangular big bales of fodder with a film. The apparatus comprises.a frame having a drivable, substantially horizontally disposed, conveyor floor, characterized in IE 970546 that the conveyor floor has boundary walls at each end, the boundary wall located at the front with respect to the direction of travel of the conveyor floor being formed as an upwardly directed, inclined conveyor. The inclined conveyor may comprise conveyor rollers, which are drivable at a greater speed of advance than the conveyor floor.

The boundary wall at the opposite end from the inclined conveyor comprises a freely rotatable, retaining roller disposed at a spacing above the conveyor floor. The apparatus described in this specification will not operate satisfactorily in practice to wrap rectangular or square bales because the drivable upwardly directed inclined conveyor is not in itself capable of tumbling rectangular and square bales about a horizontal axis.

W0-A-91/13540 (Kverneland Underhaug As) discloses a bale wrapper apparatus for applying a pre-stretched film around a bale of rectangular cross-section in order to form an air tight and water tight wrapping. The apparatus comprises a platform which rotates about a vertical axis, and a pair of rollers mounted on the platform to rotate about horizontal axes and over which slack belts are taken and which define a trough shape into which the rectangular section of the bale can be received with the upper and lower sides disposed substantially horizontally. A support is mounted on the chassis and carries a film dispenser reel and a film pre-stretcher mechanism and after attachment of the leading end of the film to the bale by manual or automatic means, combined rotation of the bale about a vertical axis and about a horizontal axis causes the film to be withdrawn and wrapped in generally helical fashion around the outer periphery of the bale. In order to compensate for possible variation in angular velocity of the rotating bale, by reason of its rectangular cross-section, (and the difficulties of engaging it uniformally with the slack belts), a guide arrangement is arranged above one of the rollers in order to engage edge regions on the longer sides of the bale cross-section and thereby prevent the bale from falling onto the roller, and also retarding the angular rotation of the bale. It is said that the function of the guide arrangement is to act on the tumbling rotation of the bale so as to maintain a substantially uniform IE 970546 - 4 rate of angular velocity during each revolution of the bale, whereby substantially uniform helical windings of film can be applied around the bale, despite its rectangular cross-section.

EP059549B discloses an apparatus for wrapping a large rectangular or square bale of fodder with a strip of wrapping material, comprising a support which is adapted to support the bale, conveying means to turn the bale about a substantially horizontal axis, and means for continuously supplying a strip of wrapping material to the bale as the bale is turned through said axis to wrap the wrapping material around the bale, and the conveying means comprises a slack endless conveyor belt suspended above the support and includes drive means for the belt such that a first portion of the belt travels upwardly in an upwardly inclined path at one end of the support while a second portion of the belt travels downwardly in a downwardly inclined path at an opposite end of the support, characterised in that the endless conveyor belt has a substantial sag in the conveyor belt which defines a cradle in the belt to receive the bale and is adapted to assume a substantially u-shape or v-shape when a bale is placed on the belt, the sag in the belt being such that there is contact between the belt and adjoining sides of the bale during rotation of the bale which maintains control of the rotational movement of the bale as the bale is turned about a horizontal axis of the bale.

Object of the Invention It is an object of the invention to provide an apparatus and a method which is suitable for wrapping bales of fodder of various shapes, in particular bales of fodder having a cross-section of square or rectangular shape, and to provide improved control of the bale during wrapping.

Summary of the Invention Accordingly, the present invention provides apparatus for wrapping bales of fodder particularly large rectangular or square bales of fodder with a strip of wrapping material, comprising a support platform, conveying means supported on the platform for supporting the - 5 IE 970546 bale and rotating the bale about a substantially horizontal axis, means for continuously supplying a strip of wrapping material to the bale as the bale is turned through said axis to wrap the wrapping material around the bale, the conveying means including a conveyor belt rotatable about two substantially parallel rollers extending transversely of the support platform and located at one end and at the opposite end respectively of the support platform, wherein the rollers are spaced above the platform, and the conveyor belt is suspended from the rollers and has a substantial sag which defines a cradle to receive the bale characterised in that the rollers are each mounted for rotation at the upper end of a respective pair of upright arms, at least one pair of arms being pivotally attached to the platform such that during movement of the belt about the rollers at least one of the rollers is free to pivot relative to the other to alter the depth of the sag in the conveyor belt and to improve contact of the belt with the bale during rotation of the bale.

Preferably, both pairs of arms are pivotally connected to the platform such that both rollers are free to pivot relative to each other. Means, such as a cam, may be provided to limit the pivotal movement of one of the rollers.

Preferably, one of the rollers is a drive roller and is mounted for rotation at the upper end of a pair of upright arms which are pivotally attached, intermediate their length, to the platform. A cam member is attached to the arms and is adjustable to at least two positions to control pivoting of the arms. Suitably, a belt tensioning roller is mounted for rotation between the lower ends of the pair of arms such that slack in the belt caused by adjusting the position of the drive roller is automatically taken up by the tensioning roller which pivots counterwise to the drive roller.

Suitably the belt travels about four rollers comprising two lower tensioning rollers disposed transversely of the turntable and located forwardly and rearwardly of the turntable respectively, and two upper rollers spaced above and parallel to the lower rollers, and wherein at IE 970546 - 5 least one of said upper rollers is a driven roller. There is considerable sag in the conveyor belt to allow it to assume a u-shape or v-shape. The belt thus forms a cradle in which the bale is nested. The sag in the conveyor belt is such that the belt comes into contact with at least two adjoining side surfaces of the bale at all times during the turning of the bale about its horizontal axis. Suitably, the tensioning rollers are adjustable.

Preferably, the platform is provided with upwardly extending restraining members which are adapted to restrain side displacement of a bale supported on the conveyor floor. The restraining members may comprise upstanding rollers provided to each lateral side of the conveyor floor and rotatable about substantially vertical axes, or axes inclined to the vertical. The restraining members may also include horizontally-disposed rollers.

The apparatus of the invention also includes a device for loading the bales, particularly long rectangular bales, onto the conveyor floor positioned on the turntable of the bale wrapping machine.

The loading device is particularly suitable for loading rectangular bales edgewise onto the conveyor floor of the bale wrapping machine with a longer side upright, and is substantially the same as that disclosed in EP 0539549, the contents of which are incorporated herein by way of reference.

The said loading device for loading bales onto the conveyor positioned on the turntable of the bale wrapping machine, comprises gripping means for gripping the bale, a lifting means for lifting the gripping means upwards through an arc of substantially 90° in a first substantially vertical plane, means fo_r moving the elevated gripping means through a further arc of substantially 90° in a second substantially vertical plane which is substantially normal to said first plane.

The gripping means comprises at least one hydraulically-operated gripping arm which is adapted to grip the bale. The gripping means may include a frame which is adapted to fit around the top sides of the IE 970546 the bale, the gripping arm being attached to one end of the frame and adapted to squeeze the bale between said arm and an end wall of the frame. The gripping arm may be pivotally mounted on the frame and operated by means of a hydraulic ram.

The gripping means may be pivotally mounted on a support structure adapted for connection to the bale wrapping machine, a first means being provided for swinging the gripping means relative to the support structure about a first horizontal pivot upwardly through an arc of substantially 90°. The support structure is pivotally connected to the bale wrapping means and a second means is provided for swinging the gripping means and support structure through a further arc of substantially 90°, about a second horizontal pivot disposed substantially normal to the first pivot.

Brief Description of the Drawings Some embodiments of the invention are hereinafter described with reference to the accompanying drawings, wherein Figure 1 is a perspective view of a typical round bale of fodder which is of cylindrical shape; Figure 2 shows a cross-section of the bale of Figure 1; Figure 3 is a perspective view of a typical square bale of fodder which is square in cross-section; Figure 4 is a cross-sectional view of the bale of Figure 3; Figure 5 is a perspective view of a typical bale of fodder which is of rectangular shape in cross-section; Figure 6 is a cross-sectional view of the bale of Figure 5; Figure 7 is a side elevation of one embodiment of a bale wrapping machine of the invention with certain parts removed for the sake of clarity; IE 970546 Figure 8 is a side elevation of part of the machine of Figure 7 showing the roller assembly; Figure 9 is a view similar to that of Figure 8 showing the rollers in a different position; Figure 10 is a side elevation showing the side opposite to that of Figure 8 but without showing the conveyor belt; Figure 11 is a side elevation similar to Figure 10 showing the drive arrangement for the rollers.

Figure 12 is a view similar to that of Figure 9 showing the wrapping of a square bale; Figure 13 is a view similar to that of Figure 10 with the bale turned into a different position; Figure 14 is a side elevation showing the tipping of the machine; Figure 15 is a rear elevation of the machine; Figure 16 is a side elevation of the machine showing a bale loading device; Figure 17 is a plan view of the machine showing the bale loading device engaging a bale of fodder; Figure 18 is a side elevation showing the bale loading device having lifted a bale through 90°; and Figure 19 is a plan view of the machine to a smaller scale, illustrating the operation of the bale lifting device; and Figure 20 is a hydraulic circuit diagram. - 9 IE 970546 Modes For Carrying Out The Invention Referring to the drawings, Figures 1 and 2 show a conventional round bale of fodder, which, in fact, is of cylindrical shape. Typically the length 1 of such bales is of the order of 1.25 to 1.5 m, and the diameter is of the order of 1.25 to 1.3m. These bales can also conveniently be wrapped using the bale wrapping machine, of the invention.

Figures 3 and 4 show a large bale of fodder which is square in cross-section. These bales which are hereinafter referred to as square bales typically include the following types of bale: Bale Manufacturer and Model Bale Dimensions (m) L x H x W Ford New Holland D1000 2.00 x 0.60 x 0.90 Ford New Holland D710 2.00 x 0.47 x 0.80 Ford New Holland D110 2.00 x 0.90 x 0.80 Hesston 4600 (in pairs) 2.00 x 0.47 x 0.80 Hesston 4700 2.00 x 0.83 x 0.78 Welger Delta 4000 2.00 x 0.70 x 0.80 Menge!e SB 8580 2.00 x 0.85 x 0.80 Claas Q1100 2.00 x 0.50 x 0.80 Krone Bigpack 80/80 2.00 x 0.80 x 0.80 The line x-y is intended to illustrate the longitudinal axis of the bale. The outline of the bale shown in broken lines is typical of a Hesston bale, while the lower portion delimited by a broken line is typical of a Ford New Holland bale.

Figures 5 and 6 illustrate a typical large rectangular bale (hereinafter referred to as a rectangular bale). The rectangular bales include the following bale types: IE 970546 Bale Manufacturer and Model Bale Dimensions (m) L x H x W Claas Quadrant Deutz Fahr G.P. 3.612 New Holland 01210 Krone Bigpack 120/80 Welger 06000 2.00 x 0.70 x 1.20 2.00 x 0.60 x 1.20 2.00 x 0.90 x 1.20 2.00 x 0.80 x 1.20 2.00 x 0.70 x 1.20 In this case, the longitudinal axis is illustrated by the broken line of z-z while the shorter transverse axis is illustrated by the broken line x-y.

Referring now to Figure 7 this shows a bale wrapping machine of the invention suitable for use in wrapping square, rectangular and round bales.

The bale wrapping machine comprises a chassis 1 having a pair of wheels 2. The chassis is provided with a hitch 3 for attachment to a tractor. A tipping platform 4 is mounted on the chassis 1. The tipping platform is pivotally connected to the chassis 1 by a main pivot 5 at the rear of the chassis 1 such that the tipping platform may be tipped to unload the wrapped bale.

The platform 4 has mounted thereon a pair of spaced rollers 10,11. The rollers are mounted for rotation about horizontal axes on pairs of pivoted arms 13, 14. An endless belt 12 is mounted rotationally about the rollers 10, 11. The rollers 10, 11 and arms 13, 14 define a well or cradle 17 which is adapted to receive a large bale of silage or other fodder for wrapping. The bale is lifted into the cradle by means of a hydraulically-operated lifting device which extends laterally from the machine, and which is described below. When in the cradle, the bale is carried on and is rotated by the conveyor belt 12.

As shown in figures 7 and 17, a film wrapping system 20 is mounted on a vertical post 21 which is positioned forwardly of the chassis 1.

A swinging arm 22 is pivotally mounted on, and extends horizontally from, the post 21 near the top thereof.

IE 970546 - 11 A rotatable hydraulic drive member 24 is mounted on the end of the swingable arm 22. This carries a rotary support arm 26 which is rotatable about a vertical axis defined by the drive member 24. A vertically disposed wrapping arm 28 depends downwardly from the end of the rotary support arm 26. The wrapping arm 28 has a dispenser 29 of plastics film rotatably mounted on the lower end thereof. The hydraulic drive member 24 can thus cause the film dispenser 29 to rotate around a bale 9 along the circular path indicated by the broken line 42 in Fig. 15.

The film dispenser 29 is of well known construction and may include a pretensioning unit through which the plastics film is fed and stretched. The film dispenser may include a cut and start device (not shown) for severing the film at the end of wrapping. A suitable cut and start device is disclosed in my patent application IE 5970060, the contents of which are incorporated herein by way of reference.

To commence wrapping a free end of the plastics film is attached to the bale 9. The film dispenser 29 is then caused to rotate around the bale 9 to wrap the bale in plastics film in well known manner.

Optionally, the film dispenser 29, together with the arms 22, 26 may be automatically raised vertically along the vertical post 21 by means of a vertically disposed hydraulic ram (not shown), which could be attached at a lower end to the post 21 and at the other end to a slidable hinge arrangement 23 for the arm 22.

A ram 27 (see Fig. 17) is disposed horizontally between the post 21 and arm 22 to cause the arm 22 to swing relative to the post 21.

The arm 26 is telescopic and is horizontally extendible, e.g. by manual means or by means of a hydraulic ram (not shown).

Referring now to Figures 8 and 9, these show details of the mounting arrangement for the conveyor belt 12. The conveyor belt is an endless belt made from a suitable rubberised fabric and may have cleats, ribs or the like on the surface thereof to improve its frictional properties. The width of the belt 12 is substantially the full width of the belt rollers 10, 11.

IE 970546 - 12 Roller 10 is rotatably journalled in flange bearings 18 mounted at the top end of each of a pair of upstanding roller support arms 13, which are located to each side of the platform 4 (see also Fig. 15).

The arms 13 are pivotally mounted, at their lower ends, in pivots 30. The roller 10 is thus free to pivot towards and away from roller 11.

Roller 11 is the main drive roller for the belt 12, and details of the chain drive for the roller are shown in Figure 11. Roller 11 is rotatably journalled in flange bearings 19 mounted atop each of a pair of upstanding roller support arms 14. The support arms 14 are each pivotally attached to the platform 4, intermediate their length, by a pivot 31.

A belt tensioning roller 32 is journalled in flange bearings 33 mounted on the lower ends of the support arms 14. Brackets 34 extend forwardly from the support arms 14, above the pivot 31, and carry flange bearings 35, between which are journalled a further belt tensioning roller 36.

At the opposite, rear, end of the platform 4 yet a further belt tensioning roller 37 is provided. The roller 37 is journalled in brackets 38. The brackets 38 are slidable in inclined guideways 39, located to each side of the platform 4, to vary the tension in the belt 12 as hereinafter described. Also, the pivots 30, for the support arms 13, are slidable, longitudinally of platform 4, in guideways 40 so as to adjust the arms 13 horizontally towards or away from the arms 14.

A tensioning and tracking roller 41 is mounted above the roller 38. The roller 41 is mounted in horizontally adjustable bearings 42. the bearings 42 are carried on the ends of screw bolts 43 which engage with brackets 44. As shown in Figure 8, the brackets 44 are bolted in holes 45 in flanges 46 welded to the platform 4. To achieve adjustment, the brackets 44 may be moved rearwardly of the machine and re-positioned by bolting to holes 47.

Thus, the endless belt 12 travels around the outside of main belt rollers 10, 11, between roller 11 and tensioning roller 36, around the outside of tensioning roller 32, around the outside of tensioning roller 37, and around the inside of roller 41.

IE 970546 - 13 The roller support arms 14, and the roller 11, are adjustable to two main positions, shown respectively in Figures 8 and 9. This adjustment is achieved by means of adjusting cams 50. The cams 50 are substantially triangular in shape and are each pivoted at their epices to brackets 34 on each of the arms 14. The opposite end of each of the cams 50 is provided with a projecting foot 52. Adjacent the foot is a flat face 53. When the arms 14 are in the position shown in Figure 8, the flat face 53 of the cam rests on a block 54. This prevents pivoting of the arm 14 to the right as shown in the drawings, i.e. away from the roller.

The cam 50 may be pivoted to the position shown in Figure 9, in which the foot 53 rests on the block 54. This has the effect of pivoting the arms 14 rearwardly of the machine, i.e. such that the roller 11 is closer to the roller 10. Again, the roller 11 is prevented by the cam 50 from pivoting in the opposite direction.

The convenient adjustability of the drive roller 11 by means of the adjusting cam 50 enables the machine to handle bales of varying shapes and sizes. For smaller bales, the cam is moved to the position shown in Fig. 9. Slack in the belt 12, caused by moving the roller 11 inwardly is, to an extent, automatically taken up by the belt tensioning roller 32 which moves in the opposite direction to the roller 11. Likewise, slack in the belt 12 may be taken up or released as desired, by suitably adjusting the rollers 37 and 41. The alternate position for rollers 37 and 41 are shown in Fig. 10, which shows the platform 4 from the side opposite to that of Figure 8.

To accommodate larger bales the roller 11 may be moved into the position shown in Figure 8, and for very large bales the arms 13 may be moved horizontally rearwards by sliding the pivot 30 along the guideway 40.

The drive means for the belt roller 11 is shown in Figure 11.

This comprises a hydraulic motor 60, which is powered from a hydraulic oil supply from the tractor (see hydraulic circuit diagram in Figure 20). The motor 60 drives a sprocket wheel 61 which is connected by a chain 62 to a larger sprocket wheel 61 which is connected by a drive chain 62 to a larger sprocket wheel 63 fixed to the end of the roller 11. IE 970546 - 14 Referring to Figure 20, the oil directional control valve 1 controls the indexing of the belt 12 as described below.

The operation of the bale wrapping machine is now described with reference to Figures 12 to 14. The square or rectangular bale 9 to be wrapped is lifted onto the belt 12 either by means of a suitable loader, or by the lifting means fitted to the machine as hereinafter described. The bale is placed on the belt 12 with the longer longitudinal axis z-z of the bale disposed tranversely of the belt 12 and cradle 17.

Plastics film from the film dispenser 29 is attached to the bale 9. The film 29 is then rotated around the bale to wrap the part of the bale exposed above the rollers 10, 11 with plastics film, in well known manner. Simultaneously, the conveyor belt 12 moves intermittently to rotate the bale 9 about the transverse axis to expose further parts of the bale for wrapping. Rotation of the bale 9 continues until the bale is fully wrapped in plastics film.

A problem associated with known bale wrapping machines, in wrapping square or rectangular bales, is that control of the bale during rotation is unsatisfactory. In certain machines the bale tends to tumble about its rotational axis. This means that rotation of the bale is uneven and a strain is placed on the conveyor belt and the rollers. This problem has been overcome to a large extent by the machine of EP 0539549 which provides for a substantial sag in the conveyor belt which achieves a more controlled rotational movement of the bale as compared to the rotary tumbling action described, for example, in WO-A-91-13540. The arrangement of the present invention, which includes a substantial sag in the belt 12, provides for an even more controlled rotation of the bale 9 about its rotational axis.

Figures 12 and 13 show the bale 9 in two different positions during rotation. It will be noted that as the bale 9 rotates the roller 10 pivots, or oscillates, in response to the position of the bale. Thus, in Figure 12, the corner of the bale is in a downward position, and the arms 13 have pivoted the roller 10 rearwardly, whereas in Figure 13, where the bale is sitting flat on the belt 12, IE 970546 - 15 the arms 13 are upright. The oscillation movement of the roller 10 ensures that the belt 12 is kept in close contact with the bale 9, and also provides a deeper cradle than hereto which results in better control of rotation of the bale. Also the roller 11 is free to pivot inwardly in response to the position of the bale which assists in controlling the rotational movement of the bale.

When the bale 9 is fully wrapped the plastics film is cut by means of the cut and start device described above. The wrapped bale 9 is then tipped from rearwardly from the machine as shown in Figure 14. Tipping is achieved by pivoting the platform 4 upwardly, about the main pivot 5, by means of a hydraulic ram 16. The wrapped bale then rolls over roller 10, which pivots outwardly, about pivot 30, to facilitate the unloading of the bale.

A hydraulically operated unloading ramp 56 (Fig. 19) may optionally be provided on the end of the machine to assist in unloading the wrapped bale.

A loading device for loading rectangular bales onto the conveyor belt 12 of the bale wrapping machine is now described with reference to Figures 15 to 19 of the accompanying drawings.

The loading device 70 for lifting a rectangular (or square) bale 9 from the ground onto the conveyor belt 12 of the bale wrapping machine is shown in Figure 16, attached to and positioned alongside the bale wrapping machine.

The loading device 70 (see fig. 16) includes a bale pick-up means 71. The bale pick-up means 71 comprises a rear rectangular frame member 72 and, at right angles thereto, a top frame member 73. A rectangular gripping frame 74 comprises a pair of parallel side members 75, a top cross-member 76 and a bottom cross-member 77. Each side member 75 has a bracket 78 attached thereto adjacent the top end of the frame member. The brackets 78 are pivotally attached by pivots 79 to the forward end of the top frame member 73, such that the gripping frame may pivot inwardly to the position shown in Figure 16. A hydraulic ram 80 is pivotally connected between a bracket 81 attached IE 970546 - 16 to the top cross-member 76 and a bracket 82 attached to the top frame member 73. The ram 80 is shown in the open position in Figure 16 and closing of the ram, causes the gripping frame to open.

The rear rectangular frame member comprises a pair of spaced parallel uprights 83 connected by transverse members 84 and 85. Each upright member 83 has a rearwardly extending bracket 86 positioned approximately mid-way of the upright member 83. Each bracket 86 carries a main pivot 87. The bale pick-up means 71 is pivotally connected through the main pivot 87 to a support structure 88. The support structure itself is carried by support bracket 90 (as best seen in Figure 15) which is pivotally connected between the chassis 4 of the bale wrapping machine and the support structure 88.

The support structure 88 comprises a ground-engaging skid 92 on which is carried a support frame having a pair of oppositely arranged plates 93 (Fig. 16). Each plate 93 is pivotally connected to the main pivot 87. A hydraulic ram 94 is positioned between the plates 93 and is pivotally connected between a pivot plate 95 on the frame of the support structure 88 and a bracket 96 attached to the lower transverse member 85 of the bale pick-up means 71.

The hydraulic ram 94 is shown in a closed position in Figure 16 but when the ram is extended this will cause the bale pick-up means 71 to pivot, through approximately 90°, upwardly in the direction shown in Figure 8.

A pair of guide rails may be positioned between the pick-up means 71 and the bale-wrapping machine to assist in guiding the bale 14 into the pick-up means.

The operation of the loading device 70 is now described. Assuming that a bale of fodder 14 (such as silage) is deposited by a baling machine on the ground, the loading device 70 is positioned, as shown in Figures 7 and 19 such that the bale fits between rear rectangular frame member 72 and the top member 73, with the rear of the bale abutting the member 72. The ram 80 is then actuated to cause the gripping frame 74 to close to the position shown in Figure 16. As will be seen in the IE 970546 - 17 drawings, the bottom cross-member 77 protrudes from the frame 74 and engages with the front end of the bale. The ram 80 causes the cross-member 77 to press firmly into the bale so as to grip the bale tightly. This gripping motion causes the bale 9 to arch upwardly which aids in securing the bale in the pick-up means.

The hydraulic ram 94 is then extended. This causes the pick-up means 71 containing the bale 14 to swing upwardly about the main pivot 87 through substantially 90° in a first vertical plane to the position as shown in Figure 18. In this position, the bale is located adjacent the cradle 17 of the bale wrapping machine.

As shown in Figure 15, a corner of the support bracket 90 is pivotally connected between the support structure 88 and the chassis 4 of the bale wrapping machine. The opposite side of the support bracket 90 is pivotally connected at one end to the support structure 88 and at the other end to the piston of a hydraulic ram 96. The cylinder of the ram 96 is pivotally connected to the chassis 4 of the bale wrapping machine. After the bale 14 has been raised to the position as shown in Figure 18 the hydraulic ram 96 is then extended as shown in Figure 15. This causes the bale pick-up means 71 to pivot inwardly, through substantially 90° in a plane substantially normal to the first plane, such that the bale 14 is positioned above the conveyor belt 12 of the bale wrapping machine, as shown in Figure 15.

The ram 80 is then withdrawn to release the gripping frame 74 from the bale. The bale is thus free to fall into the cradle 25 of the bale wrapping machine onto the conveyor floor, with a long side of the bale extending laterally.

It will be appreciated that modifications may be made to the bale loading device without departing from the scope of the invention. For example, the pick-up means could be provided with two opposed gripping jaws which act in pincer fashion. Also, the pick-up device may be provided, opposite the top frame 73, with a pair of forks which fit under the bale 14 to assist in the lifting movement.

IE 970546 - 18 One embodiment of a hydraulic circuit for controlling operation of the bale wrapping machine is shown in Figure 20. The oil directional control valve No. (1) controls the operation of the rotating arm 26, and also the indexing function of belt 12. When this section of the valve is operated oil is directed to a rotary flow divider which splits the oil flow in the ratio 66% : 33%. This division of flow is not adjustable. The 66% flow is directed to the hydraulic drive motor 24 for rotating the rotary arm 26 of the wrapping dispenser 29.

The 33% flow is directed to the hydraulic motor 60 for driving and indexing the main belt roller 11. It is critical for correct overlap of the plastics film on the bale 9 during wrapping that rotation of the indexing motor 60 and the rotary arm drive motor 24 are synchronised.

Control valve section No. (2) controls the tipping cylinder 16. Valve section No. (3) controls the hydraulic ram 94 for raising and lowering the loading device 70. Valve section No. (4) controls the hydraulic ram 80 of the bale pick-up means 71. Valve section No. (5) controls the hydraulic ram 27 for swinging the arm 22.

Modifications may be made in the bale wrapping machine of the invention without departing from the scope of the invention, for example, the platform 4 could be a rotary turntable, and the plastics film dispenser a fixed dispenser, as described in EP 539 549.

Although, described for use in wrapping square or rectangular bales, the machine of the invention is also suitable for wrapping round bales.

Claims (5)

1. Apparatus for wrapping bales of fodder particularly large rectangular or square bales of fodder with a strip of wrapping material, comprising a support platform, conveying means supported on the platform for supporting the bale and rotating the bale about a substantially horizontal axis, means for continuously supplying a strip of wrapping material to the bale as the bale is turned through said axis to wrap the wrapping material around the bale, the conveying means including a conveyor belt rotatable about two substantially parallel rollers extending transversely of the support platform and located at one end and at the opposite end respectively of the support platform, wherein the rollers are spaced above the platform, and the conveyor belt is suspended from the rollers and has a substantial sag which defines a cradle to receive the bale characterised in that the rollers are each mounted for rotation at the upper end of a respective pair of upright arms, at least one pair of arms being pivotally attached to the platform such that during movement of the belt about the rollers at least one of the rollers is free to pivot relative to the other to alter the depth of the sag in the conveyor belt and to improve contact of the belt with the bale during rotation of the bale.

2. Apparatus as claimed in Claim 1, wherein both pairs of arms are pivotally connected to the platform such that both rollers are free to pivot relative to each other.

3. Apparatus as claimed in Claim 1 or Claim 2, wherein means such as a cam, may be provided to limit the pivotal movement of one of the rollers.

4. Apparatus as claimed in any of the preceding claims wherein one of the rollers is a drive roller and is mounted for rotation at the upper end of a pair of upright arms which are pivotally attached, intermediate their length, to the platform, and a cam member is attached to the arms and is adjustable to at least two positions to control pivoting of the arms. IE 970546 - 20

5. apparatus as claimed in Claim 4, wherein a tensioning roller is mounted for rotation between the lower ends of the pair of arms such that slack in the belt caused by adjusting the position of the drive roller is automatically taken up by the tensioning roller which pivots counterwise to the drive roller.