WO1991010351A1

WO1991010351A1 - Apparatus for shredding long stem material

Info

Publication number: WO1991010351A1
Application number: PCT/GB1990/002000
Authority: WO
Inventors: Erling Roynberg
Original assignee: Kverneland Underhaug As; Orr, William, Mclean
Priority date: 1990-01-13
Filing date: 1990-12-20
Publication date: 1991-07-25
Also published as: AU6916091A

Abstract

There is disclosed apparatus (10) for shredding long stem material, such as cylindrical bales of straw or silage, and which comprises a fixed base (11), a drum (12) rotatable on the base in the direction (X) in order to guide the material towards the base and to cause it to move in a rotary movement over the base when the drum is inclined to the vertical in a working position, a rotary shredder device (13) mounted on the base (11) in a housing (15) and having a set of chopper blades (20) mounted along the length of a drive shaft (14), a slot (16) in the base (11) extending aproximately radially with respect to the centre (26) of the base and having opposed sides (16a and 16b) which define the slot (16), and a discharge outlet (17, 18) communicating with the interior of the housing and operative to discharge shredded material from the housing (15). The shaft (14) extends parallel to and along the length of the slot (16), and the upper active part of the paths of rotation of the chopper blades (20) comprises movement in a direction generally perpendicular to and between the two opposed sides (16a and 16b) of the slot (16), to provide an improved shredding effect on the material. In addition, the axis (21) of the slot (16) is forwardly inclined at an angle of preferably 30 to 60° to the vertical axis V-V, with respect to the direction of rotation (X) of the drum, in order to still further improve the shredding action applied to the material which is caused to tumble over the base as it is fed towards the action of the chopping blades.

Description

APPARATUS FOR SHREDDING LONG STEM MATERIAL

This invention relate to apparatus for shredding long stem material and which comprises a rotary drum for

receiving the material, a fixed base on which the drum is rotatably mounted, a rotary shredder device mounted in the base and operative to engage the material lying adjacent to the base and to chop or shred the material into smaller portions, and an outlet arranged to discharge the shredded material.

The invention has been developed primarily, though not exclusively, in connection with a shredding apparatus for shredding densely packed bales of long stem crop material, such as hay, straw, silage and ammonium treated straw, and which are supplied to the apparatus in the form of

cylindrical bales (known as "big bales") or as rectangular bales. The use of balers to form cylindrical bales is gaining wide acceptance by farmers, as this forms a

convenient method for handling and storing large volumes of long stem material.

However, for a long time the baled material has been distributed to farm animals either by purely manual

operations to break-up the structure of the bale and then to supply the material to the animals as feed or as

bedding, or else using relatively unsophisticated

mechanical apparatus which exert a type of tearing action on the baled material in order to break-up the structure of the bale, prior to distribution to the animals.

With these existing techniques, it is only possible to break-up the bale into the long stem material from which it has been constituted, and then to distribute this material, substantially without any appreciable shortening of the lengths of the long stem material i.e. without chopping or shredding the material into shorter lengths. This is now becoming recognised to be a disadvantage, in that cattle are not able to obtain the best utilisation of long stem material, from nutritional and other points of view, and it is now believed to be better practice to supply long stem material chopped-up into short lengths of about 10 to 20cm.

A number of bale chopper or shredder apparatus have come onto the market recently, with varying degrees of success, but it is difficult to design one single piece of apparatus which can operate reliably to chop or shred long stem material into suitable short lengths, for different types of supply of baled material. Thus, some baled material, such as hay or straw, is relatively dry, whereas other baled materials have a much higher water content e.g. silage, and are therefore more slippery and difficult to handle and to be chopped-up into required lengths.

Variable bale density also has an influence on the

shredding capability of existing shredders.

The invention therefore seeks to provide an improved design of shredder apparatus for shredding long stem material, whether supplied in cylindrical or rectangular baled form, or in loose bulk form, and in dry form such as hay, or in wetter form such as silage.

According to the invention there is provided apparatus for shredding long stem material and which comprises:

a fixed base;

a drum rotatably mounted on the base and arranged to receive the material and to guide the material towards the base, the rotation of the drum tending to move

the material in a rotary movement over the base, and the drum having a working position in which its axis is

inclined to the vertical so that controlled feeding of the material received by the drum can take place under gravity toward the base;

a rotary shredder device mounted on the base and operative to engage the material as it is moved over the base, the shredder device comprising a housing mounted on the underside of the base, a shaft mounted to

rotate in the housing, and a set of chopper blades mounted along the length ol the shaft ;

a slot in the base which extends approximately

radially with respect to the axis and over which the material is moved in a direction generally perpendicular to the sides of the slot, the slot communicating with the interior of the housing and the arrangement being such that the chopper blade are engagable with material as it moves over the slot in order to apply a shredding action on the material and to draw the shredded material into the

housing; and

a discharge outlet communicating with the

interior of the housing and operative to discharge

shredded material from the housing:

characterised in the shaft extends in a di rect ion parallel to and along the length of the slot, and is rotatable about its axis so that the chopper blades

are moveable, in the upper active part of their paths of rotat ion, in a di rection generally perpendicular to and between, the two opposed sides, of the slot.

Thus, the angle of inclination of the drum in its working position can be set to any required angle to suit the material being handled, so that control led gravity feeding of the material takes place towards the base. The angle may vary according to the material, but preferably is a relatively small angle of inclination to the horizontal i.e. in the range 10 to 30°. This then reduces the

gravitational effect, so that only a modest gravitational force urges the material towards the base, and thereby reducing the risk of the chopper blades becomi ng "choked" with excessive amounts of material to be shredeieci.

The shr e d de r appa ratus i s p ref e rably des i gne d so as t ob e capab l e of being mounted on the usual rear three point hitch of a tractor. and can therefore have the axis of the d rum adjusted to suit working requirements by operation of the t hree point hitoh. whi ch tilts the entire apparatus until the required inclination of the drum is reached. The apparatus of the invention is particularly

suitable for use in shredding densely packed cylindrical bales of hay, straw or silage, in which the bale will be loaded end-on to the drum, so that the axes of the drum and the bale are substantially parallel.

Conveniently, the shredder device is mounted for rotation in a housing arranged on the outer side of the base (the lower side in use), and a slot is formed in the base which forms an inlet to the housing and which allows the chopper blades to project into the interior of the drum during movement along the upper parts of their paths of travel during rotation of the blades.

To improve the chopping action which can be exerted on the material, preferably a fixed cutter bar is arranged along an upstream edge of the slot (with respect to the direction of movement of the material over the slot), whereby the blades can cut through the material and, if necessary, complete the cutting operation by co-operative action between the blades and the cutter bar.

Preferably, the blades are rotatable in a direction such that, in the upper active part of the path of travel of the blades, the blades move in a direction which is opposed to the direction of movement imparted to the material by the rotation of the drum.

By virtue of the countercurrent relationship between the movement of the chopper blades through the slot and the movement of the material over the slot induced by rotation of the drum, this provides a self-cleaning effect if any materials tend to become jammed around the cutter bar.

In order to further control the feeding of material into the path of action of the blades, it is preferred that a holding arrangement is arranged to extend at least partly over the slot, and this can hold the end of a bale while the chopper blades dig into the mass of the bale. The holding arrangement may comprise an arrangement of fixed knives which are spaced apart along the slot, and between which the chopper blades are movable along the upper part of their paths of action.

The housing preferably takes the form of a duct which extends at least partly around the shredder device, and which guides the shredded material (drawn into the duct by the rotating chopper blades) towards the outlet. The rotation of the chopper blades also creates a fan effect, which assists in the withdrawal of shredded material from the drum, and also causes forced discharge of the shredded material through the outlet.

The outlet may comprise a slot formed in the duct, or it may be formed by a discharge spout which can be adjusted to discharge the shredded material in any required

direction e.g. laterally onto a field, or downwardly into a feeding trough

As indicated above, a slot is formed in the base and which forms an inlet to the duct, and it has been found to be advantageous for the slot to extend generally radially of the centre of the base, and to be located in a quadrant defined between a vertical axis and a horizontal axis taken through the centre of the base, and in which the angle of the slot to the verticla axis is measured in a direction corresponding to the direction of rotation of the drum.

Preferably, the angle of the slot to the vertical is about 45°, though any angle may be adopted within the quadrant between 0 and 90°.

By arranging for the slot to be located in this quadrant, and inclined both to the horizontal and vertical axes, this assist the chopping action of the blades since the material will be partly raised against gravity by the rotation of the drum until it comes into reach of the rotat i ng chopper blades i n the reg i on of the slot , and this motion will effect a type of tumbling action on the

material which will tend to reduce its density and

effectively "fluff-up" the material so as to render it more readily chopped or shredded by the action of the rotating chopper blades.

The drum is preferably cylindrical, but to improve the feeding action of material to the base, and especially when cylindrical bales are being handled, it is preferred that a conical liner is arranged inside the drum, and which also acts to prevent material falling out from the drum during the shredding operation.

In order to load the apparatus, it may be adjusted to a loading position, in which the axis of the drum extends generally horizontally, and this enables the drum to be readily loaded with a bale by any convenient means, such as the use of a tractor mounted spike on which the bale is impaled. However, to avoid the necessity for additional equipment to be made available for this intermittent loading, the apparatus may be provided with a self loading facility.

This may comprise a loading arm or cradle arrangement coupled with the apparatus and operative to draw a bale lying on the ground into the drum, when the latter is lowered to its loading position.

Alternatively, the drum may be provided with a guide arrangement which enables a bale lying on the ground to be guided into the drum upon rearward pushing of the drum by a tractor and over the bale. In a simple form, this may comprise a cut-out portion in the wall of the drum, which can be lined up with the bale and then permit the drum to be slid under the bale. This cut-out may be closable by any suitable releasable cover plate, after the bale has been loaded into the drum.

The chopper blades are preferably mounted at uniform angular spacings throughout the periphery of a drive shaft, and axially spaced along its length. Preferably, each chopper blade is pivotally mounted on the shaft, but the pivotal mounting may be such that pivotal movement of the blades is normally resisted by a resisting force, but which can be overcome and allow each chopper blade to pivot to an inoperative position in the event of an excessive force being applied to the blade e.g. when an excessive mass of material is fed to the chopper blades.

Embodiments of shredder apparatus according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective illustration of a shredder apparatus which is adapted to be mounted on the rear three point hitch of a tractor;

Figure 2 is a view, similar to Figure 1, showing a modification applied to the apparatus of Figure 1;

Figure 3 is a rear view of the apparatus, namely the part of the apparatus which is adapted to be coupled with the three point hitch of a tractor;

Figure 3a is a rear view, similar to Figure 3 of a modified arrangment;

Figure 4 is a side view showing in detail the manner by which a rotary drum of the apparatus of Figure 3 can be driven;

Figure 4a is a view, similar to Figure 4, showing the modified arrangement of Figure 3a, and with part of the wall of the drum cut away;

Figure 5 is a detail view, to an enlarged scale, showing the base of the drum and a rotary shredder device mounted in a housing below the base;

Figure 6 is a detail view, also to an enlarged scale, taken generally in the direction of the arrow X in Figure 5, showing the manner by which the rotating chopper blades of the shredder device co-operate with the material which is to be shredded as it moves over the base of the drum towards the shredder device;

Figure 7 is a view, similar to Figure 5, showing a fixed knife type holding arrangement extending over an inlet slot in the base of the drum leading to the housing in which the shredder device is rotatably mounted; Figure 8 is a view, similar to Figure 6, showing the co-operation between the holding arrangement, the chopper blades and the base of the rotary drum;

Figures 7a and 8a are views, corresponding with

Figures 7 and 8 respectively, and of an alternative

arrangement;

Figure 9 is a side view of a loading cradle for use in loading a bale with the drum;

Figure 10 is a side view showing in more detail the construction of the chopper blades shown in figure 8

Figure 11 is a sectional view of another construction of chopper blade and showing elastomeric retarding device for maintaining the blade in any given position, unless acted upon by a pre-determined force to overcome the retarding effect;

Figure 12 shows a further chopper blade construction; and

Figure 13 shows a still further blade construction.

Referring now to the drawings, there is shown

apparatus for shredding long stem material and which is designated generally by reference 10, such material being supplied preferably in the form of a cylindrical bale of hay, straw, ammonium treated straw or silage, but which material can also be supplied in rectangular baled form, or in loose bulk form.

The apparatus 10 comprises a fixed base 11 which is circular, and on which a rotary drum 12 is rotatably mounted. The drum 12 comprises a cylindrical wall and is arranged to receive the material to be shredded, and to guide this material towards the base 11. The intended direction of rotation of the drum 12 is shown by arrows X in the drawings, and this also tends to move the material in a rotary movement over the base 11.

A rotary shredder device 13 is mounted on the base 11, and is operative to engage the material as it is moved over the base 11 by rotation of the drum 12. The shredder device 13 comprises a rotary shaft 14 (see Figures 5 and 6) which is rotatably mounted in a housing 15 secured to the underside of the base 11 and communicating with the

interior of the drum 12 via a radially extending inlet slot 16 formed in the base 11. An outlet is also provided on the apparatus to discharge material which has been shredded, and which in the illustrated embodiments

comprises a discharge spout 17 which communicates with an outlet slot 18 of the duct 15 (see Figures 6 and 8).

It should be noted particularly that the shaft 14 extends throughout the length of the slot (16) and

generally parallel to the longitudinal axis of the slot 16.

The apparatus 10 is as mentioned above, adapted to be coupled on the rear three point hitch of a tractor, and can therefore be adjusted to a horizontal loading position in which a cylindrical bale can be loaded end-on into the drum 12, and thereafter can be upwardly adjusted to a working position, as shown in Figures 1 and 2, in which the

longitudinal axis 19 of the drum is inclined to the

vertical, preferably at an angle in the range 10 to 30° to the horizontal. The entire apparatus is caused to tilt under the action of the three point linkage, in order to bring the axis of the drum to any required inclination.

This enables controlled feeding of the material received by the drum 12 under the action of gravity towards the base 11, whilst in use rotation of the drum 12 tends to cause generally rotary movement of the material over the base 11.

The shredder device 13 comprises chopper blades 20 which are pivotally mounted at angular spacings throughout the periphery of the shaft 14, and axially spaced along it, and it should be noted particularly that the axis 21 of the shaft 14 extends substantially perpendicular to the

longitudinal axis 19 of the drum 12.

Therefore, upon rotation of the shaft 14 about its axis, the chopper blades 20 are moveable, in the upper active part of their paths of rotation, in a direction generally perpendicular to, and between the two opposed sides 16a, 16b of the slot 16.

Furthermore, upon the preferred rotation of the shredder device in the direction of the arrow 22 shown in Figure 6, the upper active part of the path of travel of the blades 20 comprises movement in a direction which is opposed to the direction of movement 23 imparted to the material over the base 11 by the rotation of the drum 12. This countercurrent movement can be seen clearly from

Figures 6 and 8, which is a detailed view of the housing 15 mounted on the underside of the base 11 (this view is taken as if the drum 12 extends downwardly from the base 11).

To improve the chopping action which can be exerted on the material, a fixed cutter bar 24 is arranged along upstream side 16b of the slot 16 (with respect to the direction of movement 23), whereby the chopper blades 20 can cut through the material in the drum and, if necessary, complete the cutting operation by co-operative action between the blades and the cutter bar 24.

By virtue of the countercurrent relationship between the movement of the chopper blades 20 through the slot 16, as compared with the direction of movement of the material 23 over the base 11, this provides a self cleaning effect if any material tends to become jammed around the cutter bar 24. However, this countercurrent movement is not essential to the invention, and surprisingly it has been fouind that co-current movement also is effective in carrying out a satisfactory chopping or shredding action, and with the advantage of a reduced risk of material becoming wrapped around the chopper baldes.

In order to further improve the chopping or shredding action, a set of fixed knives 25 is arranged to extend at least partly over the slot 16, and serves to hold the end of a bale while the chopper blades 20 dig into the mass of the bale. The fixed knives are spaced apart along the slot 16 and between which the chopper blades 20 are movable along the upper part of their paths of action.

An alternative arrangement is shown in Figures 7a and 8a. in which corresponding parts have the same reference numerals. The blades 20 co-operate with the fixed knives 25, so that the fixed knives 25 hold-up the baled material ready to be engaged by the rotating blades 20, and also exert a cutting or chopping action on the material in cooperation with the rotating blades 20.

The housing 15 takes the form of a duct which extends at least partly around a shredder device 13, and which guides the shredded material drawn into the duct by the rotating chopper blades towards the outlet 18. The spout

17 shown in Figures 1 and 2 can be omitted, in which case the shredded material can be discharged directly to any desired location via the outlet 18.

It will be noted particularly from Figures 1, 2, 3, 5 and 7 that the slot 16 and the housing 15 extend generally radially outwardly of the centre 26 of the base 11 (see Figure 2) and are in fact located in a quadrant defined between a vertical axis V-V and a horizontal axis H-H taken through the centre 26 (see Figure 5) i.e. between 0 and 90° forwardly of axis V-V. This quadrant is located forwardly of the vertical with respect to the direction of rotation of the drum 12, and in the illustrated embodiment the angle between the axis 21 of the slot 16 and housing 15 to the vertical, measured in the direction of rotation of the drum 12, is designated by reference A (see Figures 3, 3a and 5), and is between 30° and 60° and preferably approximately 45°. However, the precise angle is not critical, provided only that the slot axis is located forwardly of the

vertical axis V-V with respect to the direction of rotation X of the drum.

By arranging for the slot 16 and housing 15 to be located in this forward quadrant, at an inclination both to the vertical and the horizontal axes, this assists the chopping action of the blades 20 on the material, since the material will be partly raised against gravity by the rotation of the drum 12 until it comes into reach of the action of the rotating chopper blades 20 in the region of the slot 16. This motion will effect a type of tumbling action on the material (and some of which may fall back and then be carried forward again) which will tend to reduce its density and effectively "fluff-up" the material so as to render it more readily chopped or shredded by the action of the chopper blades.

Figures 3a and 4a show a modified arrangement, according to the invention, and corresponding with Figures 3 and 4 respectively. The wall of the drum is shown cut away in Figure 4a, in order to show the way by which a bale 50 comes into shredding contact with the tips 51 of the rotating chopper blades. Figure 3a also shows the upward and outward discharge of a stream 52 shredded material from a longitudinal discharge slot 53 of the housing.

Figures 3a and 4a also show a window 54 formed in the base of the drum, through which the driver can see during reverse movement of the tractor and the apparatus (with the drum in the lowered loading position) in order to faciltate loading of a bale into the drum. The window can be covered by a flap 55 e.g. of flexible material such as plastics or canvas, when the drum is raised to its working position and is loaded with a bale.

The drum 12 has a cylindrical wall, as shown in Figure 1, but to improve the feeding action of material towards the base, and especially when cylindrical bales are being handled, a conical liner 27 may be arranged within the drum 12, as shown in Figure 2. This also prevents material falling out from the drum during the shredding operation.

A bale can be loaded into the drum 12 by the use of a tractor mounted spike, after lowering of the drum to the horizontal loading position, but as an alternative (not shown) the apparatus may be provided with a self loading facility. This may comprise a loading arm or cradle arrangement coupled with the apparatus and operative to draw a bale lying on the ground into the drum 12, when the latter is lowered to its loading position. Alternatively, the cylindrical wall of the drum 12 may be provided with a guide arrangement which enables a bale lying on the ground to be guided into the drum upon rearward pushing of the drum by a tractor and over the bale. This may comprise a cut-out portion formed in the wall of the drum, which can be lined-up with the bale and then permit the drum to be slid under the bale. This cut-out may be closed by any suitable releasable cover plate which will be closed in position once the drum has been loaded.

An alternative way of loading a bale 32 into the drum 12 is shown in Figure 9, in which a cradle 33 is first loaded with a bale e.g. by using a front loader of a tractor, and then the same tractor (with the bale shredder apparatus attached to its rear end) reverses the drum 12 over the bale 32.

Different constructions of chopper blades 20, 20a, 20b, 20c and 20d are shown in Figures 6 and 8, and also in Figures 10 to 13, from which it can be seen that they comprise relatively massive blades pivotally mounted on the outer periphery of the shaft 14. Resilient bushes 34

(Figure 11) are provided to mount the blades in position and these bushes resist pivotal movement of the blades, so that the blades tend to adopt any given position until acted upon by any substantial impact force e.g. when excessive material is supplied to the blades which might cause the blades to become jammed, in which case the blades can pivot inwardly from the operative position shown in full lines in Figure 10, to an i perative position lying alongside the outer periphery of the shaft 14. In the arrangement illustrated in Figures 5 and 7, thirty chopper blades 20 are mounted on the shaft 14, eighteen of which comprise flat chopper blades, and twelve of which have cutting edges turned-over at 90° to the general plane of the blades. This may comprise turned-over side edges 37a. as shown in Figure 10, or turned-over end edges 37b, as shown in Figure 12. This arrangement has been found to exert an efficient chopping action on baled material, so as to chop the long stem material into shorter lengths of substantially uniform size in the range 10 to 20cm.

Advantageously, at least some of the blades move alongside the edges of the fixed knives 25, in order to exert a combined cutting or chopping action on the baled material. In particular, the twin blade arrangements of Figures 11 or may operate in such a way that each blade moves along a respective side edge of a fixed knife 25, so that the fixed knife 25 is located between the circular paths of movement of the blades of each twin blade

arrangement. The fixed knives 25 therefore hold the mass baled material in position over the entrance to the slot 16 so as to be engaged by the tips of the blades (20) as they move across the slot, but also have an additional function of exerting a scissors type of cutting action on the material as the co-operating rotating blades move along the edges of the fixed knives.

The blade 20a can pivot to the position shown in dashed outline in Figure 10 under the actions of an impact, but will revert to the full line position under the action centrifugual force. Substantial inertia is stored in the rotating mass of the blade 20a, which is efective from point of action 35 in a clockwise direction about pivot 36, so as to apply a substantial impact upon the material to be chopped.

The chopper blade design shown by reference 20d in Figure 13 comprises a further alternative which can apply an improved chopping or shredding action by reason of the succesions of grooved profile 38 provided along the leading and trailing edges 39, 40 of the blade.

Any suitable means may be provided to impart rotation to the drum 12, and one arrangement is shown in detail in Figure 4, which comprises a drive shaft 28 which drives a pinion 29 in mesh with a ring gear or chain 30 arranged around the outer periphery of the drum 12.

Any suitable drive arrangement is provided to rotate the shaft 14, and when the apparatus is intended to be coupled to the rear of a tractor, preferably the source of power for operating the rotation of the drum 12 and the shredder device 13 is derived from the tractor.

However, if the apparatus is intended to be used as a fixed installation, e.g. in a barn in which bales can be stored, and from which a conveyor can lead shredded

material to animals, the apparatus may be provided with electric motors 31 which operate the apparatus.

In the illustrated embodiment, the bale material moves over the base 11 in a counter current relationship of the movement of the blades 20 through the slot 16. However, this is not essential to the invention, and the apparatus can operate effectively when the drum 12 rotates in an opposite direction to that shown by the arrows in the drawings.

Claims

1. Apparatus for shredding long stem material and which comprises:

a fixed base (11);

a drum (12) rotatably mounted on the base and arranged to receive the material and to guide the material towards the base (11), the rotation (X) of the drum (12) tending to move the material in a rotary movement over the base (11), and the drum (12) having a working position in which its axis is inclined to the vertical so that controlled feeding of the material received by the drum can take place under gravity toward the base;

a rotary shredder device (13) mounted on the base (11) and operative to engage the material as it is moved over the base, the shredder device comprising a housing (15) mounted on the underside of the base (11), a shaft (14) mounted to rotate in the housing (15), and a set of chopper blades (20) mounted along the length of the shaft (14);

a slot (16) in the base (11) which extends

approximately radially with respect to the centre (26) of the base and over which the material is moved in a

direction generally perpendicular to the sides (16a), (16b) of the slot (16), the slot communicating with the interior of the housing (15) and the arrangement being such that the chopper blades (20) are engagable with material as it moves over the slot (16) in order to apply a shredding action on the material and to draw the shredded material into the housing; and

a discharge outlet (17,18) communicating with the interior of the housing (15) and operative to discharge shredded material from the housing (15):

characterised in the shaft (14) extends in a direction parallel to and along the length of the slot (16), and is rotatable about its axis so that the chopper blades (20) are moveable, in the upper active part of their paths of rotation, in a direction generally perpendicular to. and between, the two opposed sides (16a), (16b) of the slot (16).

2. Apparatus according to claim 1, in which the blades (20) are moveable in a direction which is opposed to the direction of movement (23) imparted to the material over the base (11) by the rotation of the drum (12).

3. Apparatus according to claim 1 or 2. in which the axis (21) of the slot (16) is inclined at an angle of between 0 and 90° to the vertical (V-V), measured in a forward direction with respect to the direction of rotation (X) of the drum.

4. Apparatus according to claim 3, in which the angle of inclination of the slot (16) to the vertical is between 30 and 60°, and preferably about 45°.

5. Apparatus according to any one of claims 1 to 4, in which a fixed cutter blade (24) is arranged along an upstream edge (16b) of the slot (16).

6. Apparatus according to any one of claims 1 to 5, in which an arrangement of fixed knives (25) is arranged to extend at least partly over the slot (16).

7. Apparatus according to claim 6, in which the fixed knives (25) are spaced apart along the slot (16) and between which the chopper blades (20) are moveable in the upper part of their paths of action.

8. Apparatus according to any one of claims 1 to 7, in which the housing (15) takes the form of a duct which extends at least partly around the shredder device (13) and which guides the shredded material towards the outlet (18).

9. Apparatus according to claim 8, in which the outlet (18) comprises a slot formed in a duct (15), or is formed by a discharge spout (17) which can be adjusted to

discharge the shredded material in any required direction.

10. Apparatus according to any one of claims 1 to 9, in which a conical liner (27) is arranged within a

cylindrical wall of the drum (12).

11. Apparatus according to any of claims 1 to 10.

including a loading arm or cradle arrangement coupled with the apparatus and operative to draw a bale lying on the ground into the drum (12) when the latter is lowered to a loading position.

12. Apparatus according to any one of claims 1 to 10, in which the drum is provided with a guide arrangement which enables a bale lying on the ground to be guided into the drum on rearward pushing of the drum by a tractor and over the bale.

13. Apparatus according to claim 12, in which the guide arrangement comprises a cut-out portion formed in the wall of the drum (12), which can be lined-up with the bale and then permit the drum to be slid under the bale.

14. Apparatus according to any one of claims 1 to 13, in which the chopper blades (20) are pivotally mounted on the shaft (14).

15. Apparatus according to 14, in which the chopper blades are mounted in pairs of blades, with each pair of blades being mounted on a common pivot (36), and an

elastomeric retarding sleeve (34) is arranged on the pivot (36) and acts on the blades of each pair to oppose a pivotal movement of the blades about the pivot.

16. Apparatus according to any one of claims 1 to 15 in which at least some of the chopper blades have out- turned edges (37a), (37b).

17. Apparatus according to any one of claims 1 to 16, in which the leading and trailing edges (39), (40) of each chopper blade (20d) have grooved profiles (28) arranged along each edge.

18. Apparatus according to any one of Claims 1 to 17, in which a window (54) is arranged in the base of the drum.

19. Apparatus according to Claim 18, in which a flap (55) is arranged to cover the window at least partly when the drum is in its operating positions and / or material is loaded into the drum.