WO1995010176A1

WO1995010176A1 - Bale shredder

Info

Publication number: WO1995010176A1
Application number: PCT/GB1994/002221
Authority: WO
Inventors: David John Mehaffy
Original assignee: Kverneland Kidd Limited
Priority date: 1993-10-15
Filing date: 1994-10-12
Publication date: 1995-04-20
Also published as: GB9321358D0; AU7819194A

Abstract

There is disclosed a bale shredder comprising a rotatable bale receiving tub (12) open at one end, and closed at its opposite end by a stationary base (13), a rotor (17) disposed in alignment with an opening (16) formed in said base, the axis of rotation of the rotor being generally parallel to, but spaced from, the axis of rotation of the tub, and the rotor having a diameter which is substantially smaller than the internal diameter of the tub, one or more blades (25, 26) mounted on the rotor and engageable with a bale received within the tub, whereby, in use, a bale placed in said tub is rotated thereby whilst said blade or blades remove material from the bale, and, a raised cowling (29) associated with said rotor opening (16) in the base, said cowling (29) projecting from said base into the tub, and being disposed at the trailing region of said opening in relation to the direction of rotation of the tub.

Description

BALE SHREDDER

Background of the Invention

This invention relates to a device which is intended for use in shredding bales of material such as, for example, straw, hay or silage, primarily but not exclusively the type of bales which are known as large round bales. It will be recognised that before such baled material can be used as animal fodder or animal bedding material it is necessary to break the baled material down into a looser, and sometimes more finely divided, condition so that the material can be distributed as necessary.

A known bale shredder is disclosed in our European Patent 0244977, the design of that bale shredder being principally intended for use with hay or straw bales. Our European Application No 0407112 illustrates a variant of the bale shredder disclosed in our European Patent 0244977, having bale lifter means for facilitating the operation of the shredder with silage bales.

A difficulty sometimes encountered with known machines is that material torn from a bale, during shredding, may continue to rotate within the bale receiving drum of the machine rather than being fed through the rotor of the machine to the outlet. Such problems are more prevalent when shredding baled silage, and occur most notably towards the end of a shredding operation when there is relatively little of the bale left to be shredded. It is an object of the present invention to provide a bale shredder wherein this disadvantage is minimised or obviated. Summary of the Invention

In accordance with the invention there is provided a bale shredder comprising a rotatable bale receiving tub open at one end, and closed at its opposite end by a stationary base, a rotor disposed in alignment with an opening formed in said base, the axis of rotation of the rotor being generally parallel to, but spaced from, the axis of rotation of the tub, and the rotor having a diameter which is substantially smaller than the internal diameter of the tub, one or more blades mounted on the rotor and engagable with a bale received within the tub, whereby, in use, a bale placed in said tub is rotated thereby whilst said blade or blades remove material from the bale, and, a raised cowling associated with said rotor opening in the base, said cowling projecting from said base into the tub, and being disposed at the trailing region of said opening in relation to the direction of rotation of the tub.

In use the raised cowling intersects material torn from the bale by the rotor and directs it through the opening into the outlet arrangement of the shredder.

Preferably one or more teeth depend from the upper edge of the cowling towards the rotor opening of the base. In use said one or more depending teeth are intended to break up clumps of fibrous material torn from the bale by the action of the rotor with the aim of ensuring that the material entering the outlet arrangement of the shredder is evenly distributed.

Desirably the rotor comprises a disc arranged with its plane parallel to the plane of said base, the disc having a plurality of apertures therethrough, said apertures being equiangularly spaced about the axis of rotation of the disc and each aperture having associated therewith a scoop upstanding from the surface of the disc presented to the interior of the tub, and each scoop presenting an open face forwardly in relation to the direction of rotation of the disc.

Preferably said apertures and their associated scoops are rectilinear, and extend inwardly from the periphery of the disc.

Conveniently said rectilinear apertures and respective scoops do not extend radially, each being arranged at the same angle with respect to a radius of the disc which intersects the aperture and scoop at the periphery of the disc.

Preferably the disc carries two sets of blades extending from the face of the disc into the tub, the blades of the first set being equiangularly spaced around the axis of rotation of the disc, and being adjacent said axis, and the blades of the second set being equiangularly spaced about said axis of rotation, but being disposed adjacent the periphery of the disc.

Preferably the blades of said first and second sets are inclined with respect to the plane of the disc so as to extend outwardly from the axis of rotation of the disc.

Conveniently the angle defined between each blade and the plane of the rotor disc is between 25 and 55°. Preferably the angle of the blades of the first set is 45°.

Preferably the angle of the blades of the second set is 35°. Alternatively the angle of the blades of the first set of blades is 45° to the plane of the rotor disc and the blades of the second set are disposed alternately at 35° and 70° to the plane of the rotor disc.

Preferably the positioning of the blades of said second set on the rotor disc is such that the blades pass adjacent said one or more depending teeth of the cowling during rotation of the disc.

Desirably a blade is attached to the leading edge region of the cowling (in relation to the direction of rotation of the rotor disc) and is inclined towards the disc and inwardly towards the rotational axis of the disc so as to cooperate with the blades of said second set during rotation of the disc.

Preferably the outlet arrangement of the shredder includes a blower chamber beneath the rotor disc into which material shredded from the bale passes, and from which the material is moved both by centrifugal action, and by an air flow generated by rotation of the rotor, into an outlet duct tangential to the blower chamber.

Preferably the outlet duct conducts shredded material to an outlet conveyor which carries the shredded material to a discharge outlet.

Conveniently the discharge outlet of the conveyor includes a movable element for controlling the direction in which material is discharged.

Brief Description of the Drawings

One example of the invention as illustrated in the accompanying drawings, wherein: Figure 1 is a diagrammatic perspective view of a bale shredder;

Figure 2 is a plan view of the shredder of Figure 1 ;

Figure 3 is a transverse sectional view of part of the shredder; and

Figure 4 is a perspective representation of the part of the shredder illustrated in section in Figure 3.

Detailed Description of the Preferred Embodiment

Referring to the drawings, there is shown a bale shredder which incorporates a frame 10 whereby the shredder may be carried from the conventional three-point linkage of an agricultural tractor although it is to be understood that the manner in which the device is conveyed by an agricultural tractor is irrelevant to the present invention. Thus the shredder may be carried on the three-point linkage, or the shredder may be provided with ground engaging wheels to facilitate towing. In some situations the shredder may be a part of the fixed installation.

The shredder includes a stationary housing 1 1 upon which is mounted a generally circular, cylindrical tub 12. The tub 12 is mounted for rotation about its longitudinal axis on the housing 1 1 , and in normal operation of the shredder the tub has its rotational axis disposed vertically. Thus the tub has an open upper end through which a bale or bales to be shredded can be introduced into the tub, the opposite, lower axial end of the tub being closed by a stationary, generally horizontally extending base 13 defined by the housing 1 1. The exterior of the tub is provided with a number of axially extending strengthening ribs and the interior of the tub is provided with a plurality of spaced vanes 14 which, as shown, are of generally wedge-shaped configuration, the narrower ends being disposed adjacent the upper end of the tub. The vanes 14 are intended, in use, to grip the bale or bales of silage, straw or hay inserted into the tub so as to move the bale or bales with the tub as the tub rotates. The vanes can, if desired, be pivoted to the tub, and spring biased to protrude into the tub.

The means whereby the tub 12 is mounted for rotation on the housing 1 1 is not of significance to the invention, and conveniently incorporates a plurality of roller assembles secured to the housing 11 and supporting the tub. An hydraulic motor (not shown) is driven from the hydraulic system of the agricultural tractor associated with the shredder and rotates the tub 12 relative to the housing 11 through the intermediately of an endless chain 15 encircling the tub.

A circular aperture 16 having a diameter substantially equal to half the inner diameter of the tub 12 is formed in the base 13 offset from the midpoint of the base 13 such that the periphery of the aperture 16 passes closely proximate the inner periphery of the tub 12. Rotatable in the aperture 16 is a rotor 17 comprising a generally planar, circular disc carrying a plurality of blades and scoops to be described in more detail hereinafter.

Beneath the disc of the rotor 17 the housing 1 1 defines a cylindrical blower chamber having oppositely directed tangential outlet ducts 18, 19 (illustrated in broken lines in Figure 2). Beneath the disc of the rotor 17 the rotor 17 includes paddles 20 which, during rotation of the rotor, generate an air flow downwardly through the tub 12 and the aperture 16 and outwardly from the blower chamber through the or each outlet duct 18, 19. The axis of rotation of the rotor 17 is parallel to, but spaced from the axis of rotation of the tub 12 and the rotor 17 is driven from the power take off shaft (PTO-shaft) of the agricultural tractor through a gear box (not shown). During normal operation the direction of rotation of the rotor 17 will be the same as the direction of rotation of the tub 12 (clockwise in Figure 2) but with the speed of rotation of the rotor 17 greatly in excess of the speed of rotation of the tub 12.

A bale lifter 21 is disposed in the base 13 adjacent the aperture 16 and comprises a generally rectangular platform which can be moved from a position coplanar with the base 13 to a raised position above the plane of the base 13. As illustrated diagrammatical ly in Figure 3 the direction of movement of the lifter 21 is inclined with respect to the axis of the tub so that in addition to the platform of the lifter 21 being raised above the plane of the base 13 the platform is also moved laterally partially to overlie the rotor 17. Conveniently an hydraulic ram arrangement raises and lowers the bale lifter 21 , the lifter assembly sliding in guides provided beneath the base 13.

The rotor 17 comprises a generally planar, circular metal disc 22 having therein six equiangularly spaced rectilinear slots 23 which extend inwardly of the disc from its periphery. The slots 23 are not radially disposed, but each extends at the same angle with respect to a radius of the disc which would intersect the respective slot at the periphery of the disc. The inclination of the slots is such that the innermost end of each slot lies in advance of the outermost end of the slot in relation to the direction of rotation of the rotor.

Anchored adjustably to the disc 22 and extending along the trailing edge of each of the slots 23 is a respective scoop 24, the scoops 24 projecting upwardly above the plane of the disc 22 and forwardly in relation to the width of their respective slots 23. The height by which the scoops 24 project above the plane of the disc 22 is adjustable, although it is not intended to alter the positions of the scoops during use. Generally a setting of the scoop position which suits a particular type of operation will be determined and then maintained. It will be understood that as the rotor 17 rotates the scoops 24 assist in generating the air flow downwardly into the blower chamber.

Supported on the upper surface of the disc 22 are two sets of blades 25, 26 respectively. The first set comprises three blades 25 equiangularly spaced about the axis of rotation of the disc 22 and positioned close to the axis. The second set comprises six blades 26 equiangularly spaced around the disc 22 adjacent its periphery, a blade 26 being disposed between each adjacent pair of slots 23. Each of the blades 25, 26 is bolted to a carrier which in turn is bolted to the disc 22. The blade carriers determine the angle of presentation of the blades 25, 26 and the intention is that as the blades 25, 26 wear, then they may be replaced without the need for any complex setting up procedure, simply by bolting a new blade to the original blade carrier.

All of the blades 25, 26 are inclined with respect to the disc 22 so as to extend upwardly away from the plane of the disc 22, and outwardly from the axis of rotation of the disc. Conveniently the angle defined between each blade 25, 26 and the plane of the disc 22 lies in the range 25° to 55°, and it has been found that when the shredder is intended to be used to shred bales of silage then optimum shredding efficiency appears to be achieved with the blades 25 disposed at 45° to the plane of the disc 22 and the blades 26 disposed as 35° to the plane of the disc. As is apparent from the drawings each of the blades 25 is planar, and includes a V-shaped region protruding from the respective carrier. The edges of the V-shaped portion are bevelled from one side only of the blade to provide a cutting edge coplanar with one face of the blade. The blades 25 are arranged with their cutting edges coplanar with their upper face of the blade whereas the blades 26 are arranged alternatively with the cutting edge coplanar with the upper and lower faces.

A blade 27 similar to the blades 25 and 26 is anchored to a stationary mounting plate 28 adjacent the periphery of the aperture 16. The fixed blade 27 extends downwardly towards the plane of the disc 22, and inwardly towards the axis of rotation of the disc, and is conveniently disposed at an angle of 35° to the horizontal. The positioning of the blade 27 in relation to the blades 26 is such that the blades 26 will pass above, and closely adjacent the blade 27 as the rotor rotates so that each blade 26 will perform a shearing action when passing the blade 27.

An arcuate metal cowling 29 is anchored to the base 13 and extends around between one third, and one half of the periphery of the aperture 16, the cowling being disposed at the trailing region of the aperture 16 in relation to the direction of tub rotation. The cowling 29 extends upwardly from the plane of the base 13 and is inclined inwardly towards the axis of rotation of the rotor 17. The cowling 29 has a generally horizontal lip 31 at its upper edge, and an arcuate toothed member 32 having triangular teeth 33 is secured to the lip 31 such that the teeth 33 extend generally vertically downwards from the lip 31 towards the disc 22 of the rotor. The blades 26 pass adjacent the teeth 33 during rotation of the rotor but the gap between the blades 26 and the teeth 33 is such that substantially no shearing action occurs. It will be recognised that the cowling 29 defines a relatively large scoop at the trailing part of the periphery of the aperture 16, and the teeth 33 partially obstruct the entrance of the scoop defined by the cowl.

The outlet duct 18 terminates, at its end remote from the blower chamber, at the inlet point of an outlet conveyor assembly 35. The conveyor assembly 35 includes an elongate housing 36 of rectangular cross-section having transversely extending rollers at its opposite axial ends respectively, the rollers supporting an endless rubber belt the outer face of which is provided with upstanding cleats. The roller at the end of the housing 36 adjacent the duct 18 is driven from the drive line of the rotor 17 through a chain drive so as to rotate the endless belt. Shredded material discharged from the duct 18 to the lower end of the housing 36 is carried upwardly within the housing 36 towards the end of the housing 36 remote from the duct 18 at which point it is discharged from the housing 36. It will be recognised that the air flow along the duct 18 also passes through the housing 36 and thus assists the belt in transporting shredded material from the duct 18 to the discharge end of the housing 36. At the discharge end of the housing 36 there is provided an arcuate deflector hood 37 movable relative to the housing 36 to control the direction of discharge of shredded material from the housing 36. For example, the hood 37 can be moved from a position in which the discharge is substantially horizontal, to a position in which the hood deflects the discharged material vertically downwardly.

The shredder will incorporate flap valves operable from the tractor for controlling whether the outlet from the blower chamber is by way of the duct 18, the duct 19, or both ducts simultaneously. The duct 19 can, if desired, be fitted with a variety of different outlet arrangement known in the art.

The exact operating sequence of the shredder will to some extent be determined by the baled material which is being shredded. However, the principal of operation can be understood with reference to shredding of a large round bale of silage as will now be described.

Prior to loading the silage bale into the tub 12 the bale lifter 21 is moved to its lowermost position such that its platform is flush with the base 13, and both the tub 12 and the rotor 17 are stationary. The bale is loaded into the tub 13 through the open upper end of the tub, with the bale axis parallel to the tub axis. The bale lifter 21 is then actuated to lift the bale within the tub such that the bale is clear of the blades of the rotor 17, and drive to the rotor 17 is initialised. Unless the bale is extremely densely packed then as the lifter 21 lifts the bale parts of the bale will collapse against the rotor, but the main weight of the bale will be carried by the lifter and thus start-up of the rotor 17 will not be impeded.

The unimpeded rotor quickly achieves its intended rotational speed and the lifter 21 is then lowered to engage the bale with the rotor 17 and base 13. Thereafter the drive to the tub 12 is engaged so that the bale is rotated by the tub relative to the base 13 and across the rotating rotor 17. Parts of the bale in contact with the rotor will be shredded by the movement of the blades 25, 26 thus separating the fibrous material from a densely packed to a looser form and at the same time there will be cutting action by the blades 25 and 26 alone and in conjunction with the blade 27 to chop the fibrous material into shorter lengths. The chopped and shredded material will be collected by the scoops 24 and transported thereby and by the air flow downwardly through the slots 23 of the disc 22 into the blower chamber. Clumps of fibrous material torn from the bale which are too big to pass through the slots 23 will be thrown by the rotor and the rotation of the tub in a clockwise direction within the tub, but will be intercepted by the cowling 29 and will impact against the teeth 33. This impact, together with the movement of the blades 26 adjacent the teeth 33 will break up large clumps of fibrous material so that the material can pass between the teeth 33 to be collected by the scoops 24 and thus directed downwardly through the slots 23 into the blower chamber.

In known apparatus there is a tendency, particularly towards the end of a bale, when there is little material in the tub, for clumps of fibrous material shredded from the bale to be driven repeatedly around the tub without being broken down further by the rotor. In the apparatus described above the action of the scoops 24 in conjunction with the blades 25, 26, 27 and the cowling 29 and teeth 33 greatly minimises any tendency for clumps of material continually to circulate within the tub. In a modification the shredder control mechanism includes the facility for manually or automatically reversing the direction of rotation of the tub during processing of the last parts of the baled material after the bale has mostly been processed and the remainder has been broken into clumps. It has been found that reversal of the tub rotation at such a stage can assist in ensuring that clumps of material do not continue to circulate in the tub. Normally the reversal will be effected by the operator when he sees that clumps of material are being formed and are starting to circulate. However a weight, time, or other sensing arrangement could be provided to effect automatic tub rotation reversal at an appropriate time. The shredder is particularly adapted for use with bales of silage, but will also competently handle bales of hay and straw. Thus a farmer or other user can deal with all the usual baled materials with a single shredder. Moreover it is believed that the shredder will also handle the shredding and chopping of paper such as newspaper which may be used for animal bedding and root crops for animal feed.

The shredder described above is intended to be powered from the hydraulic system and PTO of a tractor. It is to be recognised that other power sources could be utilized, for example the shredder might be driven from a dedicated internal combustion engine or from an electric motor powered conveniently from the mains electricity supply.

The arrangement of blades 25, 26 on the rotor disc will be chosen to suit the type of blades to be processed and since these will not usually vary greatly in any given environment a suitable blade arrangement and configuration, once determined, will probably be maintained. To aid setting up a range of blade types and mounting carriers can be provided. In one modification the blades 25 and three of the blades 26 are retained as described above but three of the blades 26 are replaced by diamond shaped blades disposed at 70° to the plane of the rotor disc. The 70° blades alternate with the 35° blades and are formed of heavier gauge steel. Moreover each 70° blade is reversible on its mounting to exchange the lower apex of the diamond shape for the upper apex. To facilitate such reversal the blades are secured by single bolt to their respective carrier and the rotor disc is apertured to accommodate the lower apices of the blades. Each 70° blade has only its leading edge sharpened to form a cutting edge and so reversal of a blade about its longitudinal axis would not present a new cutting edge as is the case with the generally triangular 35° blades.

Claims

1. A bale shredder comprising a rotatable bale receiving tub (12) open at one end, and closed at its opposite end by a stationary base (13), a rotor (1 7) disposed in alignment with an opening (16) formed in said base, the axis of rotation of the rotor being generally parallel to, but spaced from, the axis of rotation of the tub, and the rotor having a diameter which is substantially smaller than the internal diameter of the tub, and one or more blades (25, 26) mounted on the rotor and engagable with a bale received within the tub, whereby, in use, a bale placed in said tub is rotated thereby whilst said blade or blades remove material from the bale, the shredder being characterized by a raised cowling (29) associated with said rotor opening (16) in the base, said cowling projecting from said base into the tub, and being disposed at the trailing region of said opening in relation to the direction of rotation of the tub.

2. A shredder as claimed in Claim 1 , characterized in that said raised cowling intersects material torn from the bale by the rotor and directs it through the opening into an outlet arrangement of the shredder below said base.

3. A shredder as claimed in Claim 1 or Claim 2, characterized by one or more teeth (33) depending from the upper edge of the cowling towards the rotor opening of the base.

4. A shredder as claimed in any one of Claims 1 to 3, characterized in that the rotor comprises a disc (22) arranged with its plane parallel to the plane of said base (13), the disc having a plurality of apertures (23) therethrough, said apertures being equiangularly spaced about the axis of rotation of the disc and each aperture having associated therewith a scoop (24) upstanding from the surface of the disc presented to the interior of the tub, and each scoop presenting an open face forwardly in relation to the direction of rotation of the disc.

5. A shredder as claimed in Claim 4, characterized in that said apertures and their associated scoops are rectilinear, and extend inwardly from the periphery of the disc.

6. A shredder as claimed in Claim 5, characterized in that said rectilinear apertures and respective scoops do not extend radially, each being arranged at the same angle with respect to a radius of the disc which intersects the aperture and scoop at the periphery of the disc.

7. A shredder as claimed in any one of Claims 4 to 6, characterized in that the disc carries two sets of blades (25, 26) extending from the face of the disc into the tub, the blades (25) of the first set being equiangularly spaced around the axis of rotation of the disc, and being adjacent said axis, and the blades (26) of the second set being equiangularly spaced about said axis of rotation, but being disposed adjacent the periphery of the disc.

8. A shredder as claimed in Claim 7, characterized in that the blades of said first and second sets are inclined with respect to the plane of the disc so as to extend outwardly from the axis of rotation of the disc.

9. A shredder as claimed in Claim 8, characterized in that the angle defined between each blade and the plane of the rotor disc is between 25 and 55°.

10. A shredder as claimed in Claim 9, characterized in that the angle of the blades of the first set is 45°.

1 1. A shredder as claimed in Claim 9 or Claim 10, characterized in that the angle of the blades of the second set is 35°.

12. A shredder as claimed in Claim 8, characterized in that the angle of the blades of the first set of blades is 45° to the plane of the rotor disc and the blades of the second set are disposed alternately at 35° and 70° to the plane of the rotor disc.

13. A shredder as claimed in any one of Claims 7 to 12 when dependent on Claim 3, characterized in that the positioning of the blades (26) of said second set on the rotor disc is such that the blades pass adjacent said one or more depending teeth (33) of the cowling during rotation of the disc.

14. A shredder as claimed in any one of Claims 7 to 13, characterized in that a blade (27) is attached to the leading edge region of the cowling (in relation to the direction of rotation of the rotor disc) and is inclined towards the disc and inwardly towards the rotational axis of the disc so as to cooperate with the blades (26) of said second set during rotation of the disc.

15. A shredder as claimed in any one of Claims 2 to 14, characterized in that the outlet arrangement of the shredder includes a blower chamber beneath the rotor disc into which material shredded from the bale passes, and from which the material is moved both by centrifugal action, and by an air flow generated by rotation of the rotor, into an outlet duct (18, 19) tangential to the blower chamber.

16. A shredder as claimed in Claim 15, characterized in that the outlet duct (18) conducts shredded material to an outlet conveyor (35) which carries the shredded material to a discharge outlet.

17. A shredder as claimed in Claim 16, characterized in that the discharge outlet of the conveyor includes a movable element (37) for controlling the direction in which material is discharged.

18. A shredder as claimed in any one of Claims 1 to 17, characterized by means for reversing the direction of tub rotation.