GB2055557A

GB2055557A - Cutting mechanism for agricultural harvesting machines

Info

Publication number: GB2055557A
Application number: GB7935411A
Authority: GB
Original assignee: Maschinenfabrik Bernard Krone GmbH and Co KG
Current assignee: Maschinenfabrik Bernard Krone GmbH and Co KG
Priority date: 1979-07-06
Filing date: 1979-10-11
Publication date: 1981-03-11
Also published as: JPS5611709A; ATA665479A; DE2927334C2; GB2055557B; FR2460604A1; DE2927334A1; FR2460604B1; AT394126B

Abstract

A row of stationary blades 25 co-operate with teeth 28 on a roller (3) to cut harvested material the knives being mounted on a carrier (10) which is pivoted as at (12, 13) so that the knives can be swung back against a spring bias to relieve major blockages. The bias may be from a controllable piston and cylinder device (18) or from a spring. The blades may be individually resiliently displaceable w.r.t. the carrier under action of spring 27. Alternatively the carrier may be formed and the only resilience may be between the individual blades and the carrier. A tined conveyor may replace the roller (3). Preferably the teeth are helically disposed on the roller. <IMAGE>

Description

SPECIFICATION Cutting mechanism for agricultural harvesting machines The invention relates to a cutting mechanism for agricultural harvesting machines.

In such cutting mechanisms, it is known to provide overload safety devices which cause the knives to swing back in the event of solid obstacles being encountered, in order to avoid damage. In the known constructions, not only is the installation and dismounting of the individual knives made more difficult by the overload safety devices but also it is very difficult to shift the knives bodily out of engagement with material being harvested in the event of a blockage of such material, of great width, occurring in front of the knives. The removal of such blockages takes a great deal of time and strength because the tractor driver must leave the tractor in order either to pull the blocked knives individually out of engagement by hand orto eliminate the blockage by turning back the material feed to the knives.

There is accordingly a need for a cutting mechanism for agricultural harvesting machines which ensures overload protection for the cutting knives in the event of solid obstacles being encountered and yet which has a simple construction which makes it possible to disengage and re-engage all the knives in the event of a blockage occurring.

The present invention provides a cutting mechanism for agrictural harvesting machines comprising a conveyor means having projections for carrying material past a row of cutting knives on a yieldable carrier which is loaded into a working position for cutting thereby to cut the material between the projections and the knives.

Apart from the overload protection for the individual knives, it is possible, with this construction according to the present invention, to relieve all the knives of load so that they can easily be retracted to remove blockages and thereafter returned to their working position simply by manipulating the carrier.

In one form of cutting mechanism according to the present invention, the knives are fixedly mounted on the carrier and the projections on the conveyor means are disposed in staggered relationship rela tire to one another in such a manner that the projections move in effective cutting relationship with the knives, in a predetermined sequence in which only one or a few of the knives are occupied in a cutting operation at any instant and the load on the carrier is sufficient merely to support a predetermined cutting force of the one or the few simultaneously effective cutting actions.

In this case, since only one or a few cutting knives come into simultaneous cutting operation, and since the load acting on the knife carrier takes this into account inasfar as it is made as small as practicable, when a solid obstacle is encountered, the knife carrier as a whole more readily retracts, so that damage to the individual knives is avoided, and afterwards immediately resumes its working position. In this manner satisfactory overload safety for the individual knives is achieved without special structural means having to be provided, because only the knife carrier as a whole is constructed for retraction or yielding in the event of overload and not the individual knives. Thus, the component and assembly cost of the cutting mechanism is simplified very considerably.It is also important that in the case of a major blockage occurring, the knife carrier, as a whole, can be easily drawn back after relieving the load on the carrier and can be thereafter returned to its working position and the working load on the carrier reinstated.

In the form of the cutting mechanism according to the invention in which the knives are fixedly mounted on the carrier, the function of overload safety for the individual knives and the function of disengaging all the knives for removing major blockages are combined in one component, namely the yieldable knife carrier which can be loaded with and relieved of a predetermined working load.

In a further form of cutting mechanism according to the present invention, the knives may be individually spring loaded and mounted on the carrier for individual pivotal movement. In this case, the individual springs are held under load by the carrier.

Specific embodiments of the present invention will now be described by way of example, and not by way of limitation, with reference to the accompanying drawings in which: Figure 1 is a diagrammatic view in section of the front portion of a n an agricultural loading vehicle hav- ing a cutting mechanism according to the present invention; Figure 2 is an individual, diagrammatic illustration of one form of cutting mechanism according to the present invention; Figure 3 is an individual, diagrammatic illustration of a further form of cutting mechanism according to the present invention; Figure 4 is a partial, perspective view of the preferred cutting mechanism according to the present invention;; Figures 5a and 5b are, respectively, a side view of a conveyor roller equipped with teeth and its flat development with respect to the arrangement of cutting knives of the cutting mechanism shown in Figure 4; Figure 6 is a side view of a still further embodiment of cutting mechanism according to the present invention; and Figure 7 is a modification of the embodiment of Figure 6.

With reference now to the accompanying drawings, the loading vehicle is an example of an application of an agricultural harvesting machine with a cutting mechanism, with which harvested material in the form of stalks or blades, lying on the field, is picked up and brought into a loading compartment, the harvested material in the form of stalks or blades being cut into short pieces by means ofthe cutting mechanism as it is carried into the loading compartment. Such a known loading vehicle is usually pulled by a tractor which also powers its various units.

The harvested material is picked up from the ground by a receiving drum 1 rotating in the direc tion of the arrow a and fed to a conveyor roller 3 which is provided with projecting teeth 2 and which rotates in the direction of the arrowb to move the harvested material upwardly along the rear wall 4 of a conveying passage formed by sheet metal parts and feed the material to a chain conveyor 5 which runs in the direction indicated by the arrows c to convey the harvested material into the loading compartment 6 of the vehicle. Strippers 7 ensure a satisfactory transfer of the harvested material from the conveyor roller 3 to the chain conveyor 5.The floor of the loading compartment 6 may be constructed in the form of a scraperconveyorto move back the harvested material, continuously or successively, towards the rear wall of the loading compartment.

The teeth 2 of the conveyor roller 3 co-operate with cutting knives 8 which are disposed side by side in a row and which project substantially horizontally into the lower portion 9 of the conveying passage.

The knives are secured rigidly on or in a knife carrier 10 disposed behind the rear wall 4 of the passage and are individually replaceable. The teeth 2 of the conveyor roller 3 are preferably constructed in the form of twin teeth each pair of which co-operate with one of the cutting knives 8, as can be seen particularly clearly from Figure 4. The knife carrier 10 with the cutting knives 8 and the conveyor roller 3 with the teeth 2 acting as a cutting roller with respect to the cutting knives, form the actual cutting device of the cutting mechanism.

As can further be seen from Figures 1 and 4, the knife carrier 10 is mounted for pivotal movement on pivot pins 12 atits sidewalls 11,the pivot pins 12 being mounted on the frame of the loading vehicle.

The pivot pins 12 lie co-axially and define an axis 13 about which the knife carrier 10 can swing back bodily, in the direction of the arrowed, carrying with it the cutting knives 8 which are rigidly secured to the knife carrier, so that the cutting knives are rearwardly yieldable with a swinging movement to pass through slits provided in the rear wall 4 ofthe conveying passage and so can be move into a disengaged position with respect to the conveyor roller 3 and its teeth 2. The rigid but replaceable mounting of the cutting knives 8 in the knife carrier 10 may appropriately be effected in such a manner that the cutting knives 8 are inserted into slots in the knife carrier 10 and are held in position by means of a securing rod 14 and plug-in keys 15.

As can further be seen from Figure 4 and 5, the twin teeth 2 are disposed in staggered relationship around the peripherally of the conveyor roller3 so that they move in a predetermined sequence into cutting relation with the cutting knives 8.

The conveyor roller 3 illustrated by way of exam ple in Figures 5a and 5b has three helically disposed rows of teeth 2, each with twelve twin teeth 2, provided around its periphery, and each extending through an angle of twist of 220 . This means, as can be seen in particular from Figure Sb, that on rotation of the conveyor roller 3, only two of the cutting knives 8 ever come into simultaneous cutting relation with teeth 2.

Taking into consideration the fact that the working width of a loading vehicle and hence also the working Width A of the cutting device is usually considerably greater than the width B of the swaths of harvested material to be picked up (for exanple working width A = 1800 mm, swath width B = 400 to 600 mm), it follows that in the example shown in Figure Sb, in relation to the swatch width B within which a cutting operation only takes place, and can take place, in practice, in fact only cutting knife 8 ever comes into cutting relation with a twin tine 2, the further, simu Itaneo U5 cutting engagement taking place outside the swatch width B being an "idle engagement" ii7asfa r as it has no harvested material to work upon. Thus, in this case, only one power peak originating from an i ncipFent cutting action ever occurs at the knife carrier 10, tending to turn the knife carrier in the direction of arrow d, that is to say, it is sufficient to act on the knife carrier 10 only with such a force as is necessary to ensure the effective cutting action of each individual cutting knife 8.

The application of this force, adapted to the number of cutting-knife engagements which are simultaneously effective, is by purely hydraulic means in the embodiment of Figures 1 and 2. The knife carrier 10 is held in its working position, with the cutting knives in the cutting position, by means of a piston and cylinder device 18 pivoted to the carrier 10 at one end, as at 16, at a position spaced above the pivotal axis 13 of the carrier and, at its other end, to the frame of the loading vehicle, as at 17. The necessary fluid pressure is applied to the piston and cylinder device 18 through a hydraulic device, for example, the hydraulic system present on the tractor, by means of a control valve 19 either on a continuous basis, in a so-called open system, or once, in a closed system.A gas pressure equalizing container which is connected to the piston and cylinder device 18 and which is adapted by design to the hydraulic working pressure (for example, of 120 bar), acts at the same time as a spring buffer or fluid pressure reservoir and makes it possible, when an obstacle is encountered at the cutting edges just coming into operation, for the knife carrier 10 to be swung back as a whole into its disengaged position and then to swing forwards again, immediately into its working position when the obstacle, for example, a branch, has passed the cutting region.The piston and cylinder device 18 can also be exhausted through the control valve 19 so that, in the event of a blockage of the harvested material occurring extending over a relatively great width in the conveying passage 9, the knife carrier 10 can be swung back to allow the blockage to be relieved. If a double-acting piston and cylinder device 18 is used, the knife carrier can be swung back using the device 18 being suitably adapted to operate the device 18 in the sense to retract the knife carrier. The control valve 19 may be operable by the tractor driver without leaving the tractor driving seat.

In the embodiment shown in Figure 3, the load for the knife carrier 10 is applied by a compression spring 21 the force of which is adjustable and which, in the simplest case, acts directly mechanically on the knife carrier through a linkage. In the examples shown, however, a hydraulic piston and cylinder device 22 is again provided which acts on the knife carrier 10 at 16, as in the embodiment of Figures 1 and 2, and is supported against the compression spring 21 the force of which is adjustable, for example, by means of a screw threaded spindle 24. The hydraulic piston and cylinder device 22 may be a closed unit which is subjected to a certain fluid pressure and which is tensioned to the necessary working pressure by means of the adjusting spring 21.

When the working pressure is exceeded due to an obstacle being encountered between a pair of cutting edges, here, too, the knife carrier 10 swings briefly into a retracted position and is then immediately swung back into its operating position by the spring 21 which, to this extent, acts in the same manner as the gas pressure reservoir 20 of Figures 1 and 2. The spring 21 can be relaxed by rotation of the spindle 24 to relieve the knife carrier 10 of load so that here, too, it can swing into its retracted position in the event of blockages. As indicated in broken lines in Figure 3, however, the hydraulic piston and cylinder device 22 can also be connected to a hydraulic device through a control valve 23 and so work in an open or closed system.In this case, the cutting mechanism can be made hydraulically exhausted so as to make it possible to swing back the knife carrier 10 into its disengaged position in order to remove a major blockage.

It should also be noted that in the embodiment of Figures 4 and 5, it is possible to vary the arrangement of the teeth 2 on the conveyor roller 3 so that a group of two or three cutting knives 8, for example, comes into simultaneous cutting action and the load acting on the knife carrier is adapted accordingly.

It is not necessary for the conveyor member 3 for supplying the harvested material to be cut to the cutting knives to be constructed in the form of a roller; instead, a section conveyor, for example, a belt or chain conveyorwith a corresponding arrangement of conveying tines, could be provided for cooperation with the cutting knives.

The Figure 6 embodiment differs from the embodiment described above in two ways.

The individual cutting knives 25 are not rigidly deployed on the pivoted knife carrier 10, but each is, in turn, pivotally movable on a pivot pin 26. In addition, associated with each cutting knife 25 is a spring 27 which resiliently supports the knife from the knife carrier. Furthermore, the conveyor roller3 is provided with teeth 28 arranged in straight instead of helical rows. As distinct from Figures 4 and 5, therefore, in Figure 6, all the cutting knives 25 come simultaneously into action with each row of teeth 28.

The pivotable knife carrier 10 is in turn loaded in order to retain the knives 25 in their working positions. Such loading can, as illustrated in Figure 6, again be effected by a piston and cylinder device 18, that is to say, in the same manner as already described with reference to Figure 2, but an arrangement as described with reference to Figure 3 may be provided. Altogether, in this embodiment, as shown in Figute 6, the arrangement is preferably such that the springs 27 associated with the cutting knives 25 are held under an initial load by the knife carrier 10 which is, in turn, acted upon hydraulically.

In the embodiment of Figure 6, the load which acts on the knife carrier 10 is considerably greater than in the embodiment of Figures 4 and 5. For in this case, where all the cutting knives 25 come into cutting engagement simultaneously with cutting teeth 28, a correspondingly greater load, adapted to this simultaneous cutting, is needed, while the overload safety device to enable yielding for minor obstacles encountered at the individual cutting knives 25 is provided by the springs 27. Here, therefore, the knife carrier 10 only responds when a relatively large obstacle is encountered extending across a large number, or all of the cutting knives 25, as is usually the case when major blockages of the material being harvested occur.

The embodiment according to Figure 7 differs from the embodiment according to Figure 6 mainly in that no conveyor roller 3 is provided but instead, a section conveyor, for example, a chain conveyor 30 carrying tines 32 disposed in parallel rows each row of tines coming into simultaneous cutting engagement with the cutting knives 25.

Claims

1. A cutting mechanism for agricultural harvesting machines comprising a conveyor means having projections for carrying material past a row of cutting knives on a yieldable carrier which is loaded into a working position for cutting thereby to cut the material between the projections and the knives.

2. A cutting mechanism as claimed in claim 1 in which the knives are individually spring loaded and mounted on the carrier for individual pivotal movement.

3. A cutting mechanism as claimed in claim 2 in which the individual springs individually loading the knives are held under load by the carrier.

4. A cutting mechanism as claimed in claim 1 in which the knives are fixedly mounted on the carrier, and the projections on the conveyor means are disposed in staggered relationship relative to one another in such a manner that the projections move in effective cutting relationship with the knives in a predetermined sequence in which only one or a few ofthe knives are occupied in a cutting operation at any instant and the load on the carrier is sufficient merely to support a predetermined cutting force of the one or the few simultaneously effective cutting actions.

5. A cutting mechanism as claimed in any preceding claim in which the carrier is loadable by means of a hydraulic piston and cylinder device.

6. A cutting mechanism as claimed in claim 5 in which the piston and cylinder device is arranged to be connected to a hydraulic device through a control valve operable to exhaust the piston and cylinder device and a gas pressure reservoir is provided to absorb transient cutting loads imposed upon the carrier.

7. A cutting mechanism as claimed in claim 5 or 6 in which the hydraulic piston and cylinder device is a double-acting device and the control valve is operable to actuate the piston and cylinder device to retract the carrier, and therefore the knives, from their working position.

8. A cutting mechanism as claimed in any preceding claim 1 to 4 in which the carrier is loadable by means of an adjustable spring load.

9. A cutting mechanism as claimed in claim 8 in which a hydraulic piston and cylinder device is provided to convey the spring load to the carrier.

10. A cutting mechanism as claimed in claim 9 in which the piston and cylinder device is arranged to be connected to a hydraulic device through a control valve operable to exhaust the piston and cylinder device.

11. An agricultural harvesting machine having a cutting mechanism as claimed in claim 5 or 10, in combination with a tractor having a hydraulic system constituting said hydraulic device, and said control valve is positioned for operation by the tractor driver from the driving seat of the tractor.

12. A cutting mechanism for an agricultural harvesting machine substantially as hereinbefore described with reference to Figures 1 and 2 or Figure 3 or Figures 4 and 5 or Figure 6 or Figure 7 ofthe accompanying drawings.

13. An agricultural harvesting machine substantially as hereinbefore described with reference to, and as shown in, Figures 1,2,4 and 5 or Figures 1,3, 4 or 5 or Figure 6 or Figure 7 of the accompanying drawings.