GB2209112A

GB2209112A - An improved agricultural forage harvesting machine

Info

Publication number: GB2209112A
Application number: GB8820383A
Authority: GB
Inventors: William Thomas Teagle
Original assignee: Teagle Machinery Ltd
Current assignee: Teagle Machinery Ltd
Priority date: 1987-08-27
Filing date: 1988-08-26
Publication date: 1989-05-04
Anticipated expiration: 2008-08-26
Also published as: GB2209263B; GB8820384D0; GB8720206D0; GB2209112B; GB8820383D0; GB2209263A

Abstract

An agricultural forage harvesting machine (11) has a rotary crop pick up device (30), conveyor means for conveying the crop to a rotary cutter assembly (25) having a plurality of blades which cooperate with a stationary shear bar (27) to cut the crop into short lengths as it passes between the shear blade (27) and a rotary cutter assembly (25). The conveyor means include a stationary curved guide (33, 34) in a fixed relationship with respect to the shear bar (27) and a rotatable crop speed control member (37, 38) mounted between the crop pick up (30) and the shear bar (27) and displaceable, against the action of a spring (43), transversely with respect to its own axis of rotation and the path of the crop as it passes towards the shear bar (27), to vary the thickness of the crop path to accommodate variations in the mass of the crop passing at any one time. <IMAGE>

Description

AN IMPROVED AGRICULTURAL FORAGE HARVESTING MACHINE The present invention relates generally to a machine for performing the agricultural task known as "forage harvesting" which is an operation forming part of the process for making silage.

Silage is a term which can be applied to a feed stuff produced from one of a number of green crops which are cut, sometimes allowed to wilt for a period, and then cut into very small pieces and stored in anaerobic conditions where an anaerobic fermentation takes place preserving the feed from deterioration usually associated with bacteriological action.In the United Kingdom the crop most frequently used for making silage is grass, and silage is made usually by first cutting the grass and allowing it to wilt for up to twenty-four hours (longer in some conditions) and. then harvesting the swaths of cut grass using a forage harvester.machine which picks up the crop, cuts or chops it very finely, and conveys it to a large container, usually a trailer, but sometimes a self-propelled vehicle, in which the wilted chopped grass is conveyed to a storage location or clamp into which it is deposited prior to being compressed to exclude an interstitial air before being enclosed. Closure of the clamp is usually achieved by covering it with an air and water impermeable opaque plastics material held down by any convenient weights.

One known type of machine for performing the forage harvesting operation comprises a rotary pick up which is mounted on a frame which may be formed as a trailed machine having its own wheels with or without a collection container, or may be formed as part of a self-propelled machine. The rotary pick up, in use, delivers the crop to a powerful rotating cutter in the form of a cylindrical drum or cutter assembly comprising a plurality of individual blades carried in long pitch helical rows to engage with shearing motion against a stationary shear bar from which the now-cut crop is conveyed by means of a tapering canopy guide to a delivery chute along which it is caused to move by rotation of the rotary cutter assembly.

Since the crop does not grow evenly over the whole of a field, the swath of grass picked up by the rotary pick up device varies in thickness or "weight" and consequently the amount of work which the rotary cutter assembly has to perform in cutting the crop, and consequently the instantaneous power requirement varies: furthermore, the guide devices which help to transfer the crop from the rotary pick up to the region where the rotary cutter assembly engages the stationary shear blade hav to be capable of displacement in a direction perpendicular to the path of the crop, in order to accommodate such variations in thickness. Usually, in order to encourage the transfer of crop from the pick up to the cutter assembly, there is provided a rotatable drum or roller system defining the crop path.The rollers of the system are mounted so that at least one can deflect in the region of the cutter assembly, in order to accommodate variations in the thickness of the swath or weight of the crop being processed at any one time. This means that the crop is delivered to the rotary cutter in different positions depending on the instantaneous thickness of the swath, which involves a compromise in the design and a loss of efficiency since the rotary cutter assembly itself has to contribute towards the effort of conveying the crop into engagement with the shear bar as well as performing the shearing action.

The present invention seeks to provide a forage harvesting machine of the general type described above in which there are a number of features which contribute to an improvement in the efficiency and therefore a reduction in the power consumption requirements of the machine.

According to the present invention, therefore, there is provided an agricultural forage harvesting machine of the type comprising a machine frame bearing a rotary crop pick up device, crop conveyor means for conveying the crop to cutter means acting to cut the crop into short lengths, and a cut crop delivery guide for guiding the cut crop to a delivery outlet from the machine, in which the crop conveyor means include a stationary curved crop guide in a fixed relationship with respect to the machine frame which defines a curved path from the crop pick up device to the cutter means along which the crop is guided with no substantial component of motion parallel to the axis of the rotary crop pick up device and a rotatable crop speed control member mounted between the crop pick up and the cutter means and displaceable, against the action of resilient biasing means1 transversely of its own axis of rotation and of the path of the crop, whereby to accommodate variations in the mass of crop picked up from time to time by the rotary crop pick up device.

Preferably the rotary crop speed control member is displaceable, against the action of resilient biasing means, transversely with respect to its own axis of rotation and the path of the crop as it passes towards the cutter means, thereby to accommodate variations in the mass of crop picked up from time to time by the rotary crop pick up device.

By forming the machine with the stationary curved crop guide in a fixed relationship with respect to the shear bar it can be ensured that the crop is always delivered to the cutters in substantially the same line, as close as possible to the point where the rotary cutter assembly meets the shear bar so that the design of the cutter profile can be made to accommodate only that orientation of the crop without having to compensate for variations in the line of the path of the crop as it arrives to the cutter. This results in a greater evenness of the chop length and an improvement in the efficiency of the machine.Although this configuration is described in detail hereinafter with reference to the drawings, it will be appreciated that other crop conveyor arrangements, including the provision of multiple rollers and/or crop conveyor augers downstream of the crop speed control member may be provided.

The rotary speed control member effectively defines one side of the crop path from the rotary pick up to the cutter assembly, the other side of which is defined by the stationary curved deflector plate, and this rotary speed control member is preferably in the form of a generally cylindrical drum or roller having a plurality of axially extending radially projecting blades or vanes.

In a preferred embodiment of the invention the said vanes have a serrated radially outer edge for engagement with the crop passing the drum or roller.

In order to achieve the object of displacement of the drum or roller constituting the rotary crop speed control member, this may be mounted at each end on respective parallel arms pivoted about a common axis on side frames of the chassis of the machine. In such an embodiment the said two parallel arms may be biased by respective springs into a position of closest approach to the said shear bar.

In the said position of closest approach the rotary speed control member, the path defined between the rotary speed control member and the stationary deflector plate is at its narrowest, and this-is preferably adjustable by varying the position of abutment means against which a part of the arms engage in the said position of closest approach.

The stationary curved guide is conveniently formed as a cover panel forming part of the canopy of the machine, which acts to guide the cut crop to the rotary speed control member.

Preferably the said cover panel is removable to allow access to the rotary speed control member and/or to the crop pick up assembly.

One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of a forage harvesting machine formed as an embodiment of the present invention; Figure 2 is a schematic section through the machine of Figure 1, illustrating the main components as seen from a longitudinal mid plane of the machine; Figure 3 is an enlarged cut away perspective view showing various components of the machine of the present invention; and Figure 4 is a schematic sectional view of a cutter blade and the cooperating shear bar.

Referring now to the drawings, the forage harvesting machine shown is generally indicated with the reference numeral 11 and comprises a main support frame generally indicated 12 comprising parallel front and rear transverse beams 13, 14 which join parallel longitudinally extending members 15, 16 (the former of which is visible in Figure 1 and the latter of which is visible in Figure 2) the forward transverse beam 13 has, attached to it, a draw bar assembly generally indicated with the reference numeral 17 and the rear transverse member 14 is in approximate alignment with the common axis of two ground-engaging wheels 18, 19.

Supported on the frame 12 is a transverse support beam 20 which carries two side plates 21, 22 which support bearings 23 for a shaft 24 for a rotary cutter assembly generally indicated 25. The rotary cutter assembly 25 comprises a plurality of cutter blades generally indicated 26 in a configuration which will be described in more detail below, which engage a stationary shear bar 27 as the assembly rotates in an anti-clockwise direction as viewed in Figures 2 and 3.

The side members 15, 16 also carry respective lateral pick up side panels 28, 29 and support a pick up rotor 30, in bearings 31 (only one of which is visible in Figure 1). The pick up rotor is provided with a plurality of resilient projecting tines in fixed positions on the rotor. Over the pick up rotor 30 extends a stationary crop guide 32 formed in two parts, a first of which, 33, extends from a lower crop pick up position adjacent the crop pick up rotor 30 and a second of which, 34, acts as a canopy between the guide plate 33 and the shear bar 27.The upper guide plate 34 is hinged to the lower guide 33 by hinges 35 and can be adjusted about the axis defined by the hinges 35 by means of two adjustors 36 to determine the precise inclination of the stationary guide and therefore the precise direction of the crop guided thereby as it contacts the cutter assembly 25. In use the crop pick up rotor is turned at relatively high speed such that crop picked up thereby is projected into contact with the stationary curved guide 32 which guides it in a curved path having no substantial component of motion parallel to the axis of the crop pick up rotor. The crop leaves the pick up rotor by centrifuge action.

In advance of the crop pick up rotor 30 is an array of adjustable flaps 69 (Figure 2) pivoted at 70 to the lower end of the stationary guide 33, and between the crop pick up rotor 30 and the cutter assembly 25 is a rotatable crop conveyor roller 37 which, as can be seen in Figure 3, has a plurality of radially extending ribs or vanes 38 having a serrated radially outer edge for engaging the crop as it passes on its way to the cutter assembly. The pick up rotor 30, the cutter assembly 25 and the conveyor roller 37 may all be driven by drive belts and pulleys or chains and sprockets (not illustrated) via a power take-off shaft 39 from the tractor which tows the machine 11. The power take-off shaft 39 drives a gear box 40 the output shaft 41 from which extends parallel to the axes of the crop pick up rotor 30 and the cutter assembly 25.

In order to accommodate variations in the thickness of the crop swath being picked up at any time, the conveyor roller 37 is mounted in such a way as to be displaceable towards and away from the stationary deflector guide 34, and for this purpose is carried at each end on arms 42 pivotally mounted to the side plates 21, 22 and each resiliently biased by a respective spring 43 towards a position of closest approach to the stationary guide 34.

By appropriately adjusting the adjustors 36 the minimum width of the space between the stationary guide 34 and the conveyor roller 37 can be set, and any crop swath thicker than this minimum can be accommodated by displacement of the roller 37 transversely of its axis away from the stationary guide surface defined by the guide 34. The crop conveyor roller 37 is driven to rotate at a speed slower than the linear speed of the crop picked up by the rotor 30 on its way to the cutter assembly 25 in order to act as a regulator to the delivery of crop to the cutter assembly 25.As can be seen in Figure 3, each of the blades 26 of the cutter assembly 25 is shaped with a planar root portion 44 and a cranked or hooked radially outer cutter portion 45 shaped in such a way that if the progress of the cutter blade 26 is imp.ded, for example by a stone or metal component picked up by the pick up rotor 30 jamming between the cutter blade and the shear bar 27, the cranked portion 45 can bend back without increasing the radial length of the blade so that subsequent damage to the cutter bar upon rotation of the damaged blade is avoided. As can be seen in Figure 3 the cutter blades 26 of the assembly are mounted in axially extended rows with the blades at the outer ends of the row leading, in a circumferential direction, the blades near the centre line of the cutter assembly. The overall shearing action of the assembly of blades 26 against the shear bar 27 thus exerts symmetrical forces on the shear bar 27 from its outer ends towards its central region, and the effect on the crop cut thereby is such as to cause this to tend to move inwardly towards the mid region of the machine. This tendency is increased by the formation of openings 46 in the support plates 47 which reinforce the blades 26 of the cutter assembly, which apertures encourage the flow of air axially of the cutter assembly from its ends towards its central region.

Above the cutter assembly 25 is a canopy generally indicated 48 leading to an upwardly extending delivery chute 49 along which the cut crop is conveyed for transfer to a container on a trailer or other vehicle for conveyance to the storage site. The canopy 48 is pivoted to the support frame of the machine between the side plates 21, 22 by a hinge 50 (Figure 3) so that it can be tipped backwardly to expose the interior of the machine for maintenance. Two fastenings 51 at the front of the canopy 48 retain it in position. The fastenings 51 are made readily releasable to facilitate this operation.

Turning now to Figure 4, the shape of the cutter blades can be seen more clearly. The root portion 44 is generally planar and has one or more slots 61 open to the root end 62 and through which pass set screws 63 by which the blade is secured to a knife holder 64. The knife holder 64 provides a shoulder 65 which supports the first bend 66 between the root portion 44 of the blade and the cranked portion 45. This latter has a second bend, 67, of greater radius than the first bend 66, and the cutting edge 68 is formed at the end of the blade remote from the root end 62.The cooperating shear blade 27 is a simple rectangular element having holes 69 formed therethrough with a bevelled end 70 at one end and a bevelled end 71 at the other so that the shear blade 27 is entirely symmetrical and can be reversed, inverted or reversed and inverted to provide four different cutting edges against which the edges 68 of the cutter blades 43 can act. This makes it a simple matter to change the position of the shear blade instead of sharpening it for in-field servicing. As mentioned above, if an extraneous body should become trapped between the cutting edge 68 of a cutter blade 26 and the shear bar 27 the cranked portion 45 of the blade 26 will bend about the first curve 66, supported by the shoulder 65 of the knife holder 64, so that the cutting edge 68 of the blade follows a line generally indicated by the arrow A of Figure 4.This maximises the radial displacement of the cutting edge 68 of the blade upon such an event in order to minimise the risk that the blade on subsequent revolutions of the rotor assembly may cause additional damage to the shear bar.

The machine of the present invention may be further provided with a blade-sharpening stone at a position remote from the line of inter-engagement between the cutters of the rotary cutter assembly 25 and the stationary shear blade 27. Such a sharpening stone (not illustrated) may be movable between a rest position out of contact with the cutter blades 26 as they rotate, and an operating position where a surface thereof is stroked by the cutter blades 26 as they pass around their rotary path. From the cutter assembly 25 there is provided a rear deflector 60 which directs any cut crop or partly cut crop which may become displaced from the normal path through the machine to the delivery chute to pass between the pick up 30 and the crop feed rotor 37 towards the rear of the cutter rotor 25.The guide 60 channels such crop back to the pick up rotor 30 from which it is recirculated to the cutter rotor.

Referring back to Figure 1, the height of the crop pick up rotor 30 (not shown in Figure 2, but visible in Figure 2) is adjustable by means of an hydraulic cylinder 75 acting between the draw bar assembly 17 and a lever 76 linked (by means not shown) to the crop pick up rotor 30.

Extension of the cylinder 75 causes the lever 76 to rise and correspondingly causes the crop pick up rotor to be raised slightly from the ground. It will be appreciated that the range of movement is relatively limited, but allows the desired height of the crop pick up rotor above the ground to be set to accommodate differences in the height of different tractor hitches from the ground, which in turn causes the height above ground of the draw bar assembly 17 to be different when connected to different tractors.

The cylinder 75 also acts to cause the crop pick up rotor 30 to rise and fall to follow variations in the.height of the ground or thickness of the crop swath, by means of a pair of guarded sensor wheels 77, one on each side of the machine (only one of which can be seen in Figure 1) carried at the end of respective pivoted feeler arms 78 mounted on respective transverse rods 79 connected by a crank arm 80 to a push rod 81 controlling an hydraulic valve 82 which directs fluid under pressure from a delivery line 83 from the tractor hydraulic system, to a control line 84 leading to the hydraulic cylinder 75.

Thus, as the wheel 77 passes over a bump in the ground or a region where the crop is thicker, it will rise to follow the contour and cause the sensor arms 78 to turn about the axis of the bar 79 thereby causing clockwise rotation of the crank arm 80 (as viewed in Figure 1) displacing the push rod 81 into the valve 82 and thereby opening the valve to allow fluid under pressure to enter the cylinder 75 and cause this to rise by a distance corresponding to the amount by which the valve 82 is opened, which in turn is determined by the degree of movement of the wheels 77. Appropriate return lines to the reservoir are also provided, but are not shown for simplicity.

Claims

1. An agricultural forage harvesting machine of the type comprising a machine frame bearing a rotary crop pick up device, crop conveyor means for conveying the crop to cutter means acting to cut the crop into short lengths, and a cut crop delivery guide for guiding the cut crop to a delivery outlet from the machine, in which the crop conveyor means include a stationary curved crop guide in a fixed relationship with respect to the machine frame which defines a curved path from the crop pick up device to the cutter means along which the crop is guided with no substantial component of motion parallel to the axis of the rotary crop pick up device and a rotatable crop speed control member mounted between the crop pick up and the cutter means and displaceable, against the action of resilient biasing means, transversely of its own axis of rotation and of the path of the crop, whereby to accommodate variations in the mass of crop picked up from time to time by the rotary crop pick up device.

2. An agricultural forage harvesting machine as claimed in Claim 1, in which the cutter means comprise a rotary cutter assembly and a cooperating shear bar mounted in a fixed position with respect to the machine frame.

3. An agricultural forage harvesting machine as claimed in Claim 2, in which the curved crop guide of the crop conveyor means is mounted in fixed relationship with respect to the shear bar.

4. An agricultural forage harvesting machine as claimed in any of Claims 1 to 3, in which the said rotary speed control member has a plurality of generally radially extending vanes.

5. A forage harvesting machine as claimed in any of Claims 1 to 4, in which the rotary speed control member is a generally cylindrical drum or rotor having a plurality of axially extending radial projections constituting the said vanes.

6. A forage harvesting machine as claimed in any preceding Claim, in which the said stationary curved crop guide of the arop conveyor passes above the rotatable crop speed control member.

7. A forage harvesting machine as claimed in any of Claims 4, 5 or 6, in which the said vanes have a serrated radially outer edge for engagement with the crop passing the drum or rotor.

8. A forage harvesting machine as claimed in any preceding Claim1 in which the said rotary speed control member is mounted at each end on respective parallel arms pivoted about a common axis on the machine frame.

9. A forage harvesting machine as claimed in Claim 8, in which the said two parallel arms are biased by respective springs into a position of closest approach to the said shear bar.

10. A forage harvesting machine as claimed in Claim 9, in which the said position of closest approach of the rotary speed control member is adjustable by varying the position of abutment means against which a part of the arms engage in the position of closest approach.

11. A forage harvesting machine as claimed in any preceding Claim, in which the said stationary curved crop guide is formed at least in part as a cover panel forming part of the canopy of the machine.

12. A forage harvesting machine as claimed in Claim 11, in which the said cover panel is removable to allow access to the rotary speed control member and/or the rotary cutter assembly.

13. A forage harvesting machine as claimed in any preceding Claim, in which there is provided a rear fixed guide acting to divert any uncut crop passing the rotary cutter assembly and not being delivered to the delivery outlet from the machine back to the conveyor means for conveying the crop to the rotary cutter assembly.

14. An agricultural forage harvesting machine as claimed in any of Claims 11 to 13, in which the said canopy is pivotally mounted to the machine frame along a line parallel to the axis of the rotary cutter assembly and rearwardly thereof with respect to the direction of advance of the machine in use, and there are provided releasable fastenings along a forward edge of the canopy which can be released to allow the canopy and the delivery duct supported thereby to be pivoted about the horizontal axis to expose the crop conveyor, the rotatable crop speed control member and the rotary cutter assembly for maintenance.

15. An agricultural forage harvesting machine as claimed in Claim 15 or Claim 16, in which there is further provided a rigid support extending upwardly from the canopy for supporting the said delivery duct.

16. An agricultural forage harvesting machine as claimed in any preceding Claim, in which there are provided means for varying the height of the rotary crop pick up device.in relation to a frame of the machine, means for detecting the separation between a part of the said frame and the surface over which the machine is passing at any given instant, and control means operable to cause the said rotary crop pick up device to be raised or lowered with respect to the said frame in dependence on the instantaneous separation between the said part of the frame and the underlying surface as detected by the said sensor, whereby to maintain constant the height of the rotary crop pick up above the ground.

17. An agricultural forage harvesting machine as claimed in any preceding Claim, in which the cutter means comprise blades each of which has a blade root portion for attachment to a rotary blade carrier and a blade body portion formed with a cutting edge adapted to cooperate with a stationary shear bar to cut by shearing action, in which the blade body portion is so shaped that if it encounters in use resistance to movement beyond its yield point the blade bends in such a way that movement of the cutting edge contains no radially outward component.

18. An agricultural forage harvesting machine as claimed in Claim 17, in which the blade root portion is substantially planar and the blade body portion comprises a first part curved in one direction and a second part curved in the opposite direction.

19. An agricultural forage harvesting machine as claimed in Claim 17 or Claim 18, in which the root portion is substantially planar and the cutting edge of the blade body portion lies offset from the plane defined by the blade root portion.

20. An agricultural forage harvesting machine as claimed in Claim 19, in which the cutting edge of the blade body portion is offset from the plane defined by the blade root portion in a direction such as to lie behind the said plane with reference to the direction of movement of the blade in use.

21. An agricultural forage harvesting machine as claimed in any of Claims 17 to 20, in which the blade root portion includes means for removable attachment of the blade to a blade carrier of a rotary cutter assembly.

22. An agricultural forage harvesting machine as claimed in any of Claims 17 to 21, in which the root portion includes means by which the position of the blade on a blade carrier of a rotary cutter assembly is adjustable.

23. An agricultural forage harvesting machine as claimed in any preceding Claim having a rotary cutter assembly comprising a plurality of elongate blade carriers extending longitudinally of the assembly and each equipped with a plurality of cutter blades as claimed in any of claims from 18 to 23 such that the cutting edges of the body portions thereof all lie on a common cylindrical surface.

24. An agricultural forage harvesting machine as claimed in Claim 23, in which each cutter blade is mounted on the blade carrier in such a way that its cutting edge is inclined to a generatrix of the cylindrical surface passing through the cutting edge itself, and the blades are arranged in rows such that the cutting edges of the blades of a row define at least part of a-helix on the cylindrical surface.

25. An agricultural forage harvesting machine as claimed in Claim 24, in which the rows of cutters are positioned such that the helices defined by the cutting edges thereof turn in opposite directional senses on either side of a median plane transgress the axis of rotation of the assembly.

26. An agricultural forage harvesting machine as claimed in Claim 25, in which the cutter blades are oriented such that the leading end of each cutting edge with respect to the direction of rotation of the cutter assembly in use, in the end nearest the nearer end of the assembly.

27. An agricultural forage harvesting machine as claimed in any of Claims 17 to 26, in which the cutting edges of the cutter blades of the assembly are provided with a layer of a chromium or a tungsten alloy.

28. An agricultural forage harvesting machine as claimed in any of Claims 17 to 27, in which the blade carriers are mounted on a plurality of support plates or frames which lie in a series of planes perpendicular to the axis of the rotary cutter assembly, each having one or a plurality of openings for allowing airflow from the ends of the rotary cutter assembly axially inwards towards the central region thereof.

29. An agricultural forage harvesting machine as claimed in any preceding Claim, in which the crop pick up rotor has a plurality of fixed resilient tines and the rotor is rotated in use at a speed such that the crop leaves the pick up rotor substantially by centrifugal action.

30. An agricultural forage harvesting machine substantially as hereinbefore described with reference to and as shown in the accompanying drawings.