GB2037556A - Chaff cutter and feeding mechanism thereof - Google Patents

Abstract

In a chaff cutter having two pairs of co-operating pressure rollers 8, 5 and 15, 4 arranged before the cutting mechanism, the top rollers 8, 15 of each pair are interconnected by a lever system 10, (13), 23, 19 whereby when the top upstream roller 15 yields with increased material feed, the top downstream roller 8 is entrained upwardly only after a given initial upward movement of roller 15 so that the intake gap is always narrowing towards the cutting mechanism. <IMAGE>

Description

SPECIFICATION Chaff cutter, in particular field chaff cutter, compris ing a cutting mechanism and a press system preced ing the same The invention relates to a chaff cutter, in particular a field chaff cutter, comprising a cutting mechanism whereof the cutting aperture is preceded by a press system consisting of two press rollers installed one over the other right in front of the cutting aperture and of two initial press rollers installed one over the other and in front of the said press rollers, the bot tom press roller and the bottom initial press roller being rotatably installed in unit with the machine, whereas the top press roller is mounted via a bear ing on the extremity of an approximately horizon tally extending first pivoting lever which is pivotable in a vertical plane by means of a pivot bearing in unit with the machine, the bearing forth top press roller acting as a pivot bearing for a second equally approximately horizontally extending pivoting lever pivotable in a vertical plane, on whose free extremity the top initial press roller is rotatably journalled by means of a bearing and which is acted upon by a spring thrusting the top press roller and the top initial press roller against the bottom rollers.

Chaff cutters of this kind have been in use for a long time. In chaff cutters of this nature, the cutting quality is closely linked to the degree of initial com pression of the material which is to be cut, the mater ial having to be maintained in the compressed state until it is gripped by the cutters, since a clean cut can be obtained with little power demand in this manner only. In the known chaff cutter of this kind, the initial press rollers consequently have a relatively small diameter and are installed right in front of the cutting aperture. The diameter of the initial press rollers arranged close to the press rollers should however be chosen somewhat larger because in case of a sudden greater infeed of material which is to be cut, the latter could not otherwise be grasped for intake and would accumulate in front of the initial press rollers.If so large an infeed of material which is to be cut occurs on a known chaff cutter of this kind, the top initial roller retreats very far in upward direction againsttheforce of the spring, whereasthetop press roller is pulled downward with great force by virtue of the increasing return force of the spring, which causes vthe forming of the wedge-shaped intake gap narrowing considerably towards the cutting aperture of the chaff cutter. The very large fodder block car ried onwards by the initial press roller can no longer be gripped by the press roller because it cannot run up on to so large a fodder block, so that clogging of the chaff cutter occurs in these cases. This risk arises in particular upon harvesting grass silage.It also happens in such cases, that the fodder block is so large that it may only just be pulled in by the press roller whilst the press roller is carried tar in upward direction against the force of the spring. The initial press roller has however been returned to its original position at this instant so that a tangent touching the press roller and the initial press roller subtends an angle with the intake table which opens towards the cutting aperture. If the large fodder block is followed by a normal intake of fodder in this condition, the initial press roller substantially retains its position.

The press roller is however still displaced upwards so that the following block of fodder is no longer under a compressive pressure after passing the initial press roller and consequently cannot be cut neatly and with low power demand.

The invention has the object of devising a chaff cutter of the nature defined in the foregoing in such manner that the compression of the fodder material which is to be cut is assured without the risk of clogging, notwithstanding the varying quantity of the fodder in-feed.

For resolution of this problem, the invention specifies for a chaff cutter of the kind described in the foregoing, that the first pivoting lever has articulated on it between the two bearings, the extremity of a coupling lever branching off upwards approximately vertically, which engages with a peg secured on the other extremity in an elongated guide limited by a bottom stop of an entraining lever which has its other extremity articulated on the second pivoting lever, the coupling peg being guided so that it is displaceable approximately vertically.

It is accomplished by these measures that in case of a suddenly occurring very large fodder infeed, and following a particular upward displacement of the initial press roller, the press roller mandatorily participates in this upward displacement, so that the press roller is also reliably apt to draw in so large a quantity of fodder, so that a clogging action is averted even in such unfavourable conditions.

Beyond this, it is also assured however, that the intake gap can never widen towards the cutting aperture, so that the material safely remains compressed right in front of the cutting apertures and may thus be cut neatly and with little power demand.

In accordance with the invention, a crank arm pivotable around a bearing in unit with the machine may be incorporated for the approximately vertically displaceable guiding of the coupling peg. This leads to a structure which is particularly uncomplicated and reliable even during rough usage of the chaff cutters.

For optimum determination of the angle of taper of the intake gap, the bottom stop delimiting the longitudinal guide may be arranged in longitudinally displaceable and immobilisable manner on the entraining lever in accordance with the invention. A supportive action may concomitantly be provided if the coupling ped is displaceable and immobilisable in the longitudinal direction of the coupling lever.

An example of embodiment of the invention is illustrated diagrammatically in the drawings. In these: Fig. 1 shows a side view of the cutting mechanism and of the press device, with a fore-mounted receiving device of the chaff cutter; This print takes account of replacement documents later filed to enable the application to comply with the formal requirements of the Patents Rules 1978. Fig. 2 shows a plan view of the press device cross-sectioned along line ll-ll in fig. 1 and Fig. 3 shows a plan view of the press device cross-sectioned along line Ill-Ill in fig. 1.

In the example of embodiment illustrated, the cutting system 2 comprises a disc wheel 27 whereon are fastened cutting blades 28 which are displaced to run past close to the cutting bar 29 forming the mating cutting edge in the area of the cutting aperture 18. The cutting system 2 is preceded by a press device marked 1 as a whole, to which the material which is to be cut is fed by a receiving device marked 3 as a whole.

The press device comprises a bottom press roller 5 which is fixedlyjournalled rotatably within the machine frame 6 closely in front of the cutting aperture 18, and a bottom initial press roller4 equally rotatablyjournalled at a fixed point on the machine frame 6 and closely in front of said roller 5, these bottom rollers 4 and 5 being so arranged that a tangent to both rollers rises shallowly towards the cutting aperture 18. An endlessly circulating initial press belt could also be applied instead of the initial press roller 4. The bottom rollers 4 and 5 may be driven in conventional manner.

A first pivoting lever 10 extending approximately horizontally is arranged to be pivotable in a vertical plane on the machine frame 6 by means of a pivot bearing 11. The spindle 7 for the top press roller 8 is journalled at the other extremity of the first pivoting lever by means of a bearing 9. Apart from the bearing 9, the spindle 7 also has installed on it another bearing 12 for a second pivoting lever 13 which equally extends approximately horizontally and is pivotable in a vertical plane. At its free extremity, this second pivoting lever 13 carries the spindle 16 for the top initial press roller 15 via a bearing 14 (fig. 2).

As apparent from fig. 1, a traction spring 30 acts on the second pivoting lever 13, said spring thrusting the top press roller8 and top initial press roller 15 against the co-operating bottom rollers 5 and 4.

Between the two bearings 9 and 11, the first pivoting lever 10 has articulated on it the extremity of an approximately vertically upwardly branching off coupling lever 23 which at the other extremity comprises a laterally projecting coupling peg 20 which is guided approximately vertically, in such manner that the coupling peg 20 engages in a corresponding bore at the extremity of a crank arm 21 which is pivotablyjournalled by means of a bearing 22 in unit with the machine.

The coupling peg 20 moreover projects into a longitudinal slot 31 which is wrought in an extremity of an entraining lever 19, whereof the other extremity is articulated on the second pivoting lever 13. The longitudinal guide in the form of an elongated slot 31 is downwardly delimited by a stop 24.

So that the coupling peg 20 may slide in the longitudinal guide 31 without jamming, it is equipped with a roller 32 (fig. 3).

As apparent from fig. 1,the upward displacement of the top press roller 8 is delimited by a stop 25, for example in the form of a resilient buffer.

The top initial press roller is coupled to the central driving system via an universal joint 33. A sprocket 34 which drives a sprocket 35 fastened on the spindle 16 ofthetop initial press roller via an endless chain 17 is keyed on the spindle 7 of the top press roller8 between the bearings 9 and 12.

The mode of operation of the press system is described in the following.

When a very large block of fodder is suddenly fed to the top initial press roller 15 by the receiving device 3, the top initial press roller 15 gives way upwards against the force of the spring 30. After a particular yielding trajectory, the stop of the entraining lever 19 which accompanies the yielding displacement, concomitantly strikes the roller 32 of the coupling peg 20 which then consequently also participates in the upward displacement of the top initial press roller 15, whilst describing an arc around the machine-mounted bearing of the crank arm 21.

Since the coupling peg 20 is an integral component of the coupling arm 23, the latter is entrained by the coupling peg 20, so that the first pivoting lever 10 is then pivoted upwards around the machine-mounted pivot bearing 11. The top press roller 8 which is jour nalled on the extremity of the first pivoting lever 10 consequently and mandatorily participates in the upward displacement of the top initial press roller 15 after a particular period.

The conjoint upward displacement of the top press roller 8 and of the top initial press roller 15 is delimited by the resilient stop 25 which is impinged upon by the bearing 9 ofthetop press roller 8.

The top press roller 8 and the top initial press roller 15 are drawn in the form of thin lines in this terminal position in fig. 1. It is apparent therefrom that a tangent scribed on the two rollers 8 and 15 subtends an intake gap narrowing towards the cutting aperture 18 with a tangent scribed on the bottom rollers 5 and 4.

The action coupling the top initial press roller 15 to the top press roller 8 after an unaccompanied displacement of the former assures that a very large block of fodder passing through the initial press rollers 15 and 4 encounters a sufficiently great intake gap between the press rollers 8 and 5, so that clogging is precluded even in such extreme cases, whilst the compressing action is nevertheless still performed between the press rollers 8 and 5.

If so large a block of fodder is fed to the cutting aperture 18 from the press rollers 8 and 5, and the receiving device 3 simultaneously feeds a substantially smaller quantity of fodder material which is to be cut to the initial press rollers 15 and 4, the top initial press roller 15 is downwardly displaceable to a particular extent independently of the top press roller 8, so that this smaller quantity of fodder is also compressed by the initial press rollers 4 and 15. This downward displacement of the top initial press roller 15 is limited however, by the length of the slot 31.

When the press rollers 8 and 5 have delivered the large block of fodder together to the cutting aperture 18, the top press roller 8 is immediately impelled towards the bottom press roller 5 by the spring 30, so that the smaller block of fodder grasped by the initial press rollers 15 and 4 is fed to the two press rollers 8 and 5 in a position in which they already form a narrow intake gap again, so that the lesser quantity of fodder is also comprsssed under great force in front of the cutting aperture.

To render the conditions for the forming of the intake gap as favourable as possible, the stop 24 which delimits the bottom of the elongated slot 31 in the entraining lever 19 may be made longitudinally displaceable and immobilisable. Furthermore, the coupling point 36 of the coupling lever 23 may be organised to be displaceable and immobilisable in the longitudinal direction on the first pivoting lever 10. It is possible moreover to install the coupling peg 20 displaceably and immobilisably in the longitudinal direction of the coupling lever 23.

Instead of guiding the coupling peg 20 by means of the crank arm 20, a connecting link guide system may also be incorporated in the machine frame.

In the example of embodiment illustrated, a pair of first pivoting levers 10, furthermore a pair of second pivoting levers 13, moreover of entraining levers 19 as well as of crank arms 21 and of coupling levers 23, are incorporated for mounting as well as coupling the top initial press roller 15 and the top press roller 8. This results in a particularly rigid and troublefree mounting and displacement transmission system. It may also be envisaged however to provde no more than one of the one component or the other, for lesser requirements.

The structure of the press system is primarily advantageous in the case of field chaff cutters comprising a receiving device for grass silage making.

The favourable operating conditions may however also play a great part in the case of stationary chaff cutters. The press system may however also be applied advantageously on field chaff cutters from harvesting maize.

Claims (7)

1. Chaff cutter, in particular field chaff cutter, comprising a cutting mechanism whereof the cutting aperture is preceded by a press system consisting of two press rollers arranged one over the other right in front of the cutting aperture and of two initial press rollers arranged one over the other and in front of said press rollers, the bottom press roller and the bottom initial press roller being rotatablyjournalled in unit with the machine, whereas the top press roller is installed via a bearing at the extremity of an approximately horizontally extending first pivoting lever which is pivotable in a vertical plane by means of a machine-mounted pivot bearing, the bearing for the top press roller acting as a pivot bearing for a second equally approximately horizontally extending pivoting lever pivotable in a vertical plane, on whose free extremity the top initial press roller is rotatablyjournalled by means of a bearing and which is acted upon by a spring thrusting the top press roller and the top initial press roller against the lower rollers, characterised in that between the two bearings (9 and 11) the first pivoting lever (13) has articulated on it the extremity of an approximately vertically upwardly branching off coupling lever (23) which engages with a peg (20) secured at the other extremity in a longitudinal guide (31) delimited by a bottom stop (24) of an entraining lever (19) which has its other extremity articulated on the second pivoting lever (14), the coupling peg (20) being displaceably guided in approximately vertical direction.

2. Chaff cutter according to claim 1, characterised in that a crank arm (21) pivotable around a machine-mounted bearing (22) is incorporated for approximately vertically displaceable guiding of the coupling peg (20).

3. Chaff cutter according to claim 1 or 2, characterised in that the bottom stop (24) delimiting the longitudinal guide (31) is installed longitudinally displaceably and immobilisably on the entraining lever (19).

4. Chaff cutter according to at least one of the claims 1 to 3, characterised in that the pointofarticu- lation (36) of the coupling lever (23) on the first pivoting lever (10) is arranged to be displaceable and immobilisable on the longitudinal direction of the latter.

5. Chaff cutter according to one at least of the claims 1 to 4, characterised in that the coupling peg (20) is displaceable and immobilisable in the longitudinal direction of the coupling lever (23).

6. Chaff cutter according to at least one of the claim 1 to 5, characterised in that the upward displacement of the top press roller (8) is delimited buy a stop (25).

7. A chaff cutter substantially as hereinbefore described with reference to the accompanying drawings.