GB2142222A - Comminution apparatus - Google Patents

Abstract

A device for comminuting cut crop or other material comprises first and second knife cassettes 40, 42 connected together as part of a parallelogram linkage including top and bottom rocker arms 32, 38. In operation of the device, a connecting rod 30 is driven from a flywheel to rock the arms 32, 38 about support shafts 34, 36. This results in a substantially vertical reciprocatory movement of the two cassettes and the vertical material- comminuting knives that they contain. Each cassette can be readily replaced by another having knives at different spacings. A horizontally-disposed reciprocating flow-splitter knife 50 may be positioned upstream of the cassettes. <IMAGE>

Description

SPECIFICATION Comminution apparatus The invention relates to apparatus for comminuting cutcropand other materials and to knife-bearing cassettestfor use in such apparatus, The invention also relates, but not exclusively, to forage harvesters, balers or like machines, e.g. forage wagons or pick-up balers, incorporating apparatus for comminuting crop handled by the machine.

Examples of such machines are already known. In one known forage harvester, for example, the crop is comminuted by a flywheel-type chopper using what is termed the double chop principle, i.e. a flail type cutting/pick-up mechanism which causes a degree of comminution before the crop is fed into the flywheel chopper proper.

In other known forage harvesters, the crop is cut in the horizontal plane by shear or impact, or alternatively pre-cut crop is picked up by a tine-bar mechanism, before being conveyed to a flywheel of cylinder-type chopping mechanism. Both these types of chopping mechanism have multiple knives attached to a highspeed rotor, which cut the layer of crop presented to them into lengths by single shear as the crop layer passes overthe edge of a ledger plate. The knives and/or special blades then impel the chopped crop through a chute and ducting into a collecting trailer or container. Some current forage harvesters additionally have special blower units to ensure good delivery irrespective ofthe settings and state of maintenance of relevant cutting components.

Similarly in a known self-loading, crop-slicing forage wagon, the crop, after having been picked up by a conventional tine-bar mechanism, passes into a ducting through which it is elevated by sets of heavy paired tines on a conveyor chain. Intruding into the ducting, usually from below, are two banks of stationary serrated knives over which the crop is forced in such a way that one of each tine pair passes on either side of knife in one bank and both tines pass between knives in the other bank. This is a typical arrangement, but different makes of forage wagon use designs of knives and conveying means which differ in detail. The principle used may be described as slicing a low density column crop by multiple shear achieved by conveying components which actually intrude into, and practically all ofthe way through, the crop layer.

In the above systems, the cutting means rely for their effectiveness either on their movement through the crop or on intimate co-operation with some other means moving through the crop to produce a shear.

This requirement results in these existing chopping systems having a relatively high power demand, susceptibility to expensive damage by foreign objects mixedwiththe crop,the need for precision in settling the mechanismsto perform effectively and efficiently, high maintenance requirement, and - in the case of Ioaderwagons-a degree ofcomminution which is inadequate for some purposes.

UK Patent Application 8031503 describes an arrangement in which a column of cut crop is forced through an array of crop-comminuting knives each effective to cutthe crop column along a cutting plane containing the cutting edge ofthat knife and lying substantially parallel to the direction of crop advancement.

This latter arrangement has significant advantages overthe earlier systems and it is an object ofthe present invention to provide a means of further enhancing these advantages.

According to the present invention, a cassette for use in a crop-comminution process or other materialcomminution process comprises a frame unit and a plurality of material-comminuting knives mounted on and held in position acrosstheframe unit with their cutting edges parallel to one another and transversely spaced apart along a width or other dimension of the frame unit.

Conveniently, the cassette includes adjustable tensioning meansforthe knives.

Conveniently, in this latter case, the tensioning meansforeach knife comprises a knife-tensioning memberand a tension-adjustment member engaging one another at an angle so that controlled sliding movement ofthe tension-adjustment member over the knife-tensioning member with a component of motion at right angles to the length dimension ofthe knife results in a corresponding movement of the knife-tensioning memberin a direction parallel to said dimension.

Conveniently, the tensioning means is provided at a first end ofthe knife and the second end ofthe knife is provided with a lateral projection adapted to be engages in the slot of a locating bracketforthatend.

The invention also includes an apparatus for comminuting cut crop or other material comprising a cassette according to the present invention and drive means for reciprocating the cassette substantially wholly in a plane lying across e.g. substantially perpendicular to, the direction of material advancemeritthrough the apparatus, the cutting edges of the knivesfacing into the advancing material and extending in the direction in which the cassette reciprocates.

It is an advantage of material-com minuting apparatus according to the present invention that the cassette can bye readily interchanged e.g. to provide differing numbers of knives at different spacings. To facilitate this interchange, the cassette may, for example, be provided with a fastening means at only a first end of the cassette positively to secure the cassette in place in the apparatus while the other end ofthe cassette is free to disengage from the apparatus on release ofthe fastening means at said first end.

Conveniently, the material-comminuting knives are substantially vertically disposed and arranged to reciprocate in a substantially vertical motion.

It is an advantage of apparatus according to the present invention that the drive means may act on whatever constitutes the most convenient part of the cassette frame in the particular configuration chosen.

Conveniently, the cassette is driven from a flywheel The drawing(s) originally filed was/were informal and the print here reproduced is taken from a later filed formal copy.

orthe like.

Conveniently, in this latter case, the axle of the flywheel orthe like extends across the path ofthe advancing material from which it is shielded by a material-flow divider positioned upstream ofthe axle.

Clearly, the material-flow divider and any item or items shielded by the dividerwill usually extend substantially perpendicularlyto the knives and the direction of knife reciprocation.

Conveniently, the material-flow divider provides guide meansforthe central regions of the materialcomminuting knives e.g. to reduce the risk of the knives twisting under high material loads.

Conveniently, the leading edge ofthe material-flow divider has material-cutting properties so as to assist in comminution and, in the case of a material-flow divider providing a cutting edge to the advancing material, also to enhance the effectiveness to the divider in discouraging movement of material in the directions of knife reciprocation.

Conveniently, the material-flow divider is arranged to be reciprocated in directions substantially perpendicularto the direction of material advancement through the apparatus.

Conveniently, the cutting mechanism is capable of at least some degree of movement in the direction of material advancementwheneverthe material advancement rate exceeds the material-comminuting rate of which the knives are capable e.g. as will occur when high instantaneous loads are imposed on the knives by intermittent advancement of the material to be comminuted. In this case, the apparatus includes biassing means adapted to urge the cassette back towards its "low load" position with the result that the reciprocating knives will cuttheirway back through the material wheneverthe material advancement rate becomes less than the material-comminuting rate of which the knives are capable. This enables the knives to be maintained in a comminuting relationship with the material throughout the advancement cycle ofthe material.

In one such arrangement, the frames,and conveniently any linkage of which they form a part, can retract pivotally in pendulum fashion, e.g. about a top or bottom horizontal shaft in the case of vertically reciprocating vertical knives which may be the drive shaft. Alternatively, or additionally, theframes, and conveniently any lonkage ofwhich theyform a part, may retract bodily in the direction of material advancement, e.g. by a horizontal sliding movement along appropriate rails or tracks. One or more compression our tension springs can provide a convenient biassing meansfor urging theframestowards their low load positions as above described.

Conveniently, the cassette is one of two such cassettes spaced apart in the direction of material advancement and the drive means is operative to drive the two cassettes in a counter-reciprocating motion lying substantially wholly in planeswhich lie across e.g. substantially perpendicular to, said direction.

The term "counter-reciprocating" in this context and throughoutthis application is used to describe the motion of any two items which reciprocate in substan tially parallel directions and at substantially 180 degrees outof phase with one another.

Conveniently, in this latter case, the materialcomminuting knive ofthe two cassettes are offset in opposite directions so as to be effective to slice the advancing material at an identical or closely adjacent cross-sectional plane.

Conveniently, the side members oftheframe units ofthe two cassettes form part of a linkage which may, for example, be parallelogram-shaped when viewed from the side ofthe apparatus.

Conveniently, the apparatus ofthe present invention has associated with it means for automatically interrupting an advancement mechanism for the material in responseto anoverloadsituation atthe material-comminuting apparatus.

The invention also includes a baler, forage harvester or like agricultural machine including a materialcomminuting apparatus accordingtothe present invention for comminuting cut cropreceived by the apparatus during operation of themachine. In these cases, the automatic interruptionmeans referred to above might, for example, compriseasensoror mechanical link between the retracting cutting mechanism and a component capable of interrupting the drive to the baleretc.

Embodiments ofthe invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figures 1 and 2 are side and plan views of a first machine according to the present invention; Figures 3 and 4 are part sections of the same machine taken along arrowsAAand CC respectively; Figure 5 is a frontview ofthe cassette assemblies and mounting shafts; Figures 6,7,8(a) and 8(b) showfurther details of the knife assembly used in the machine of Figures 1 to 5; and Figure 9 is a rearview ofthe machine of Figures 1 to 8 being towed behind a tractor-drawn baler.

Thus referring now to the drawings, a fabricated horizontal chassis 10 for a trailed baler attachment 11 according to the present invention is supported on two laterally spaced left-hand and right-hand castor wheels 12,12' byclevises 14,14'.

Two laterally spaced arms 16,16' atthefrontofthe chassis and two similarly spaced arms18,18' atthe rear of the chassis extend upwardlytoprnvide pivotal supports attheir upper end for afabricated frame structure 19.

Supported on this structure.-ia power unit 20 (omitted from Figure 2) the.qutCut-sh-aft22 of which is connected to the drive pull' potrvee belt 24 by a centrifugal clutch 25. The bettZ4intum drives a 45 kilogram flywheel 26 hexing a cranked output shaft 28, shown 90 displaced in FigureS relative to the position illustrated in Figure t. For clarity, the belt drive shown in Figures 1 and 2 has been omitted from Figures 3 and 4.

Laterally spaced connecting rods 30,30' driven from the cranked portions of the shaft 28 provide the drive to upper left-hand and right-hand rocker arms 32,32'.

The latter are adapted to pivot about a central shaft 34.

The lower rockerarms 38, 38' are similarlyadapted to pivot about a second shaft36. Both the shafts 34 and 36 are supported from the front end offrame 19 as clearly seen from Figure 1.

Reference numerals 40,42 refer to first and second knife cassettes, each of which comprises a rectangular frame spanned by thin, straight, vertically-disposed parallel crop-comminuting knives 44.

Angled wing brackets 39,43 pivotally connect the upper and lower cross-members of the cassette frames to the appropriate ends ofthe rocker arms 32, 38 etc. so that rotation of the shaft 28 will result in a substantially vertical counter-reciprocating motion of the frames and their knives 44.

The lower brackets 43 are provided with semicircular cut outs located in recessed bosses on the pivot shafts 45 by which these brackets are attached to rocker arms 38,38'.

Reference numerals 41 indicate bolts by which the brackets 39 are attached to the uppercross-members ofthe cassette frames. At their upper ends, the brackets 39 wholly embrace the pivotshafts by which they are connected to the rocker arms 32,32'.

Both the upper and lower pivot shafts are provided with appropriate bearings as shown in Figure 6.

Figure 6 also shows howthe knives 44 of each cassette 40,42 are offset relative to the frame for that cassette so as to lie in planes parallel to the planes occupied by the frames. In one cassette (40) the offset is downstream ofthe crop flow and in the other cassette (42) it is upstream so thatthe cutting edges of the two sets of knives slightly overlap (or meet at) a cross-sectional plane iying at right-anglestothe direction of crop advancement.

The relative dispositions of the knives 44 in the two frames is such that the first, third and fifth knives etc.

of the resulting array will be associated with one cassette frame whereas the second, fourth and sixth knives etc. will be associated with the other cassette frame.

Turning nowto the suspension system for the cassettes, the two pairs of upright suspension arms used for this purpose allow the whole of the drive and cutting assembly including knives 44,flywheel 26 and power unit 20 to pivot rearwardly in response to peak load conditions, e.g. occuring as a result ofthe intermittent movement ofthe crop column in the direction of crop advancement. An adjustable stop 70 (Figure 1) provided with a resilient pad may be positioned to prevent the assembly from pivoting furtherthan intended in the direction of crop advancement.

Tension springes 71 attached atthefront to the machine chassis and to upright members ofthe frame 19 operateto return the assemblyto its normal position between successive strokes ofthe cropadvancement piston. Thus, the reciprocating knives 44 do not have to cope with high instantaneous crop loads but only have to be able to complete the slicing of each crop charge within the full cycle time of the crop-advancement piston.

Positioned upstream of the two cassettes at approx imately half their effective vertical height is a horizontally disposed flow-splitter knife 50 effective to part the crop column before it reaches the knives 44. Aframe 46 provides this knife with the necessary support.

In operation, this knife will be reciprocated from side to side in a horizontal plane by a cam 60 (Figure 3). This cam is bolted to the inside surface of the rotating flywheel 26 and engages with a freely rotating cam follower 58 secured to a drive plate 56 forthe knife 50.

Reference numerals 48 indicate horizontal guides for the reciprocating knife 50.

As best seen from Figures 3 and 4, a horizontal plate 52 positioned downstream ofthe knife 50 is provided with narrow guide recesses which accommodate the knives 44 and preventthem from twisting under load.

Further downstream, a guide plate extension and shroud 54shieldstheflywheel shaft 28 from the advancing crop flow.

It is to be understood that the vertical cropcomminuting knives 44 and the more substantial horizontal flow-splitter knife 50 may have plain, serrated, wavy or any othersuitably-profiled cutting edges designed to cut forage crops efficiently.

In operation ofthe baler attachment 11 described above, a column of cut crop from the baler (not shown) will approach the attachment from the leftasviewed in Figure 1. After splitting by the horizontally oscillating knife 50, the crop will pass on to the vertically counter-reciprocating knives 44 of cassettes 40 and 42 for efficient comminution as above described.

On leaving the knives 44, the comminuted crop will be carried away by a mechanical crop conveyor (68) into an appropriate bulktrailer(notshown). Reference numeral 66 indicates an angled base plate for distributing the comminuted crop evenly across the width ofthe conveyor 68.

With an engine speed of 3000 revolutions per minutes, say, for power unit 20, the knives 44,50 might typically reciprocate at 400 cycles per minute. The vertical stroke for knives 44 might typically be about 30-50 mm in these circumstances with a similar horizontal stroke length for knife 50.

For an explanation of the detailed construction of the cassettes 40,42 reference should first be made to Figure 8(a) which shows that at the lower end ofthe cassette 40, the bottom cross-member ofthe cassette frame has a knife-offsetting bracket 49 attached to it with each vertical knife 44 introduced through a slot in the bodyofthe bracket and located and held by the head being seated atthe end ofthe slot. Figure8(b) illustrates in cross-sectional view how the ends of each vertical knife 44 are formed from an Allan screw and one threaded and one recessed metal collar. Thus, the holethrough the knife need only have the diameter oftheAllen screw.

At its upper end (Figure 7), the cassette 40 is provided with a knife-tensioning mechanism in which athreaded bolt 47 with a slanted lug passesthrough the upper cross-member of the cassette frame.

Loosely fitted over the bolt is a bracket 51 with slanting top, the vertical knife provided with a head assembly 53 being introduced through a slot in the side of the bracket and located in a semi-circular recess. On the tightening the nut of the bolt 47 the slanted lug at the end is pulled to the left and thus raises the bracket which, in turn, tightens the knife.

Identical arrangements to those shown in Figures 7, 8(a) and 8(b) are also provided for cassette 42 though in this case, when seen in side view, they will be the mirror image ofthose illustrated.

The mounting of the vertical knives 44 includes the slotted U-sectioned member of Figure 7 which is designed so that any broken parts are retained. This member also stabilises bracket 51.

With a suitably recessed front base and top plate and central dividing plate it is possible to change quicklyfrom one chop length to another by substituting cassettes having knives spaced apart at different lateral clearances. To remove a cassette, the centre knife 50 is withdrawn, the locking pins holding support frame 46 in position are removed and frame 46 is lifted out. Nextthe recessed base plate 64 is swung upwards and after removal of the securing bolts (41) the cassettes may be withdrawn.

Coupling ofthe attachment 11, e.g. to the rear of a baler, requires removal ofthe bale chute and is effected bytwo pairs of vertical lugs 62,62' atthefront ofthe chassis engaging with single lugs provided beneath the bale chamber at the rear of the baler. This, the attachment is coupled rigidly laterally but is able to pivot in the vertical plane relative to the cross-section ofthe bale chamber. During turns ofthe complete outfit at corners or when following bends in the windrows, its castor wheels allow the attachment to followthe baler.

Figure 9 illustrates the attachment in rearview towed behind the offset pick-up balerwhich, in turn, is drawn behind a tractor and driven from its top. A cowling covers the engine exceptforthe air intake and exhaust. The mechanical conveyor for the chopped crop is shown under the chassis of the attachment with the elevator section inclined upwardly to the left.

While the comminution apparatus described above is intended for use with a trailed baler attachment as shown, the same apparatus is also suitable for building into a balerorforage harvester as an integral partofsuch harvesting machines. Moreover it should benotedthatthefeatureofa pivoted-arm assembly, to retract under excess load conditions and to ensure effective cutting all of the time, has alternatives. For example, as mentioned in the introductory portions of the Application, the cutting mechanism can be mounted to slide horizontally on railsortracksorthe frames supporting the banks ofvertical knives can pivot pendulum fashion about a horizontal overhead shaft which may be the drive shaft.

Retraction of the crop comminuting attachment may also be achieved by linking the unitto the baler etc. by means of telescopic resilient arms. Also, to prevent serious damage due to excess load conditions of foreign objects, one or more sensors or a linkage may be combined with the retraction mechanism, the signal from the sensor or sensor or the movement of the linkage being used, for example, to trip the plunger stop mechanism ofthe baler or like machine so that the machine's drive is interrupted by induced failure of a drive line shear bolt.

Is should also be noted thatthe specific power unit 20 shown in the Figures can be replaced by any other suitable unit if desired, for example, buy a hydraulic motor or motors and other alternatives.

An alternative form of drive may be achieved if the power unit, ofwhateverform, is attached in a fixed position to the chassis in line with the lowerfront pivot axis ofthe support linkage and the flywheel and crankshaft are mounted above in line with the upper front pivot axis.

The attachment may be used also in a stationary manner, if necessary without being attachedto a baler ortractor, to slice hay, straw or other materials including horticultural wastes and by-products for a large number of purposes. Alternative provisions may be madeforfeeding such materials into the slicing mechanism.

Claims (19)

1. For use in a crop-comminution process or other material-comminution process, a cassette comprising a frame unit and a plurality of material-comminuting knives mounted on and held in position across the frame unit with their cutting edges parallel to one another and transversely spaced apart along a width orotherdimesnion oftheframe unit.

2. A cassette as claimed in Claim 1 including adjustable tensioning meansforthe knives.

3. A cassette as claimed in Claim 2 in which the tensioning means for each knife comprises a knifetensioning member and a tension-adjustment member engaging one another at an angle so that controlled sliding movement of the tension-adjustment memberoverthe knife-tensioning memberwith a component of motion at right angles to the length dimension of the knife results in a corresponding movement ofthe knife-tensioning member in a direction parallel to said dimension.

4. A cassette as claimed in Claim 3 in which the tensioning means is provided at a first end ofthe knife and the second end of the knife is provided with a lateral projection adapted to be engaged in the slot of a locating bracketforthatend.

5. An apparatus for comminuting cut crop or other material comprising a cassette as claimed in any of Claims 1 to 4 and drive means for reciprocating the cassette substantially wholly in a plane lying across the direction of material advancement through the apparatus, the cutting edges ofthe knives facing into the advancing material and extending in the direction in which the cassette reciprocates.

6. An apparatus as claimed in Claim 5 in which a fastening means is provided at a first end ofthe cassette positively to secure the cassette in place in the apparatus while the other end of the cassette is free to disengage from the apparatus on release of the fastening means atsaid first end.

7. An apparatus as claimed in Claim 5 or Claim 6 in which the material-comminuting knives are substantially vertically disposed and arranged to reciprocate in a substantially vertical motion.

8. An apparatus as claimed in any of Claims 5to 7 in which the cassette is driven from a flywheel orthe like.

9. An apparatus as claimed in Claim 8 in which the axle ofthe flywheel ofthe like extends across the path oftheadvancing materialfromwhich it is shielded by a material-flow divider positioned upstream ofthe axle.

10. An apparatus as claimed in Claim 9 in which the material-flow divider provides guide means for the central regions of the material-comminuting knives.

11. An apparatus as claimed in Claim 9 or Claim 10 in which the leading edge ofthe material-flow divider has material-cutting properties and is arranged to be reciprocated or otherwise driven in directions substantially perpendicularto the direction of material advancementthrough the apparatus.

12. An apparatus as claimed in any of Claims 5to 11 in which the cassette is capable of at least some degree of movement in the direction of material advancement whenever the material advancement rate exceeds the material-comminuting rate of which the knives are capable, the apparatus including biassing meansadaptedto urgethe cassette towards its low load position with the resultthatthe reciprocating knives will cuttheirway backthrough the material whenever the material advancement rate becomes less than said material-comminuting rate.

13. An apparatus as claimed in any of Claims 5 to 12 in which the cassette is one of two such cassettes spaced apart in the direction of material advancement and the drive means is operative to drive the two cassettes in a counter-reciprocating motion lying substantially wholly in planes which lie across said direction.

14. An apparatus as claimed in Claim 13 in which the material-comminuting knives ofthetwo cassettes are offset in opposite directions so as to be effective to slice the advancing material atan identical or closely adjacent cross-sectional plane.

15. An apparatus as claimed in Claim 13 orClaim 14 in which the side members ofthe frame units of the two cassettes form part of a linkage.

16. An apparatus as claimed in Claim 15 in which the linkage is parallelogram-shaped when viewed from the side of the apparatus.

17. An apparatus as claimed in any of Claims 5 to 16 with associated means for automatically interrupting an advancement mechanismforthe material in response to an overload situation atthe materialcomminuting apparatus.

18. An apparatus or cassette substantially as hereinbefore described with reference to and/or as illustrated in Figures 1 to 9 ofthe accompanying drawings.

19. A baler, forage harvester or like agricultural machine including a material-comminuting apparatus as claimed in any of Claims 5 to 18forcomminuting cut crop received by the apparatus during operation of the machine.