GB2056836A

GB2056836A - Agricultural machine with three upright rotors

Info

Publication number: GB2056836A
Application number: GB8027101A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-08-22
Filing date: 1980-08-20
Publication date: 1981-03-25
Also published as: GB2056836B

Abstract

An agricultural machine such as a pasture topper with three upright working rotors 12 has the rotors driven by a single V belt 32 which drives the central rotor in the opposite sense to the other two, the pulley 22 of this rotor being driven with the back 48 of the belt 32. The belt tension is adjusted by lateral movement bodily of the driving pulley 34 together with a right angle gearbox 36 which is coupled to the rear power take off of the towing tractor. <IMAGE>

Description

SPECIFICATION Agricultural machine with three upright rotors This invention relates to agricultural machines of the kind having a plurality of rotary working elements each of which rotates about a generally upright axis and which are spaced transversely across the machine. Such machines include rotary mowers, and pasture toppers in both of which the rotary working elements have cutting blades at their periphery and also tedders in which rotary working elements are fitted at their periphery with tines to move a previously cut crop. The present invention is concerned with machines having three rotary working elements and is directed to the means by which the three working elements are driven.

The invention is of particular applicability to pasture toppers which are machines used for cutting off rough growth, thistles, nettles and so on during the summer months. It is desirable that machines built for this purpose are of very economical construction as otherwise farmers tend to feel that the machine is too expensive for carrying out an operation which is not totally essential. In particular, although not exclusively, the present invention is concerned to provide an inexpensive belt drive system for a pasture topper having three upright spindle cutting rotors. Moreover, it provides a system in which the belt tension can be adjusted without difficulty.

According to the present invention there is provided an agricultural pasture topper, rotary mower or tedder having three cutting or tedding rotors distributed across the transverse width of the machine, each rotor being arranged to rotate around a generally upright axis and driven by means of a pulley or sprocket on that axis, characterised in that the central rotor is arranged to rotate in the opposite sense to the other two, all three rotors being driven by a single driving belt or chain passing over the said driven pulley or sprocket of each rotor and also over a driving pulley or sprocket, provision being made for adjustment of the tension of the belt or chain by movement of the axis of the said driving pulley or sprocket.

It is convenient for the driving pulley or sprocket to be on the vertical output shaft of a right angle gearbox having a horizontal input shaft which can be driven by the rear power take off of an agricultural tractor towing the machine. Then, adjustment of the tension of the belt or chain can be effected by laterally moving the gearbox and the driving pulley or sprocket as one unit. In a preferred arrangement the belt or chain runs from the driving pulley or sprocket around the driven pulley or sprocket on one outer rotor then around that on the other outer rotor thirdly around the driven pulley or sprocket of the central rotor and thereafter back to the driving pulley.If the drive is by means of a V belt it will be the flat back face of the belt which drives the central driven pulley and it is then desirable to arrange that the belt wraps around the central driven pulley for a large arc, preferably at least 220 , more preferably about 235 or even more.

A pasture topper embodying this invention will now be described with reference to the accompanying, diagrammatic, drawings wherein: Figure 1 is a diagrammatic top plan view showing the belt layout; Figure 2 is a view of the central cutting rotor looking in the direction of the arrow A in Fig. 1; and Figure 3 is a perspective view showing an arrangement for adjustably mounting the gearbox and driving pulley to enable adjustment of the belt tension.

The pasture topper includes a main structural member 10 of box section extending from side to side across the machine between upright side plates. Along the bottom edges of these there are skids 10 (not shown) on which the machine travels in use. The box section members 10 supports three cutting rotors 1 2 which are of generally similar construction.

Each rotor has an upright spindle 14 supported in bearings 1 6 fixed to the box section member 10. At the lower end of the spindle 14 there is a transverse arm 1 8 which carries cutters 20. Fixed to the upper end of the spindle 1 4 is a driven pulley 22, 23 or 24.

The rotors do not themselves make any contact with the ground but are supported solely from above as shown by Fig. 2. Each cutter 20 is pivoted at 26 to the arm 1 8 and is provided with cutting edges on its lower most portion 28. During use the cutters 20 are centrifuged outwardly as shown but if one of them strikes an obstruction it can swing back around its pivot 26 (in manner known per se) to avoid the obstructions. The circles swept out by the cutters are indicated by numeral 30.

As shown by Fig. 1, the central rotor is set slightly forward from the two outer rotors and turns in the opposite sense (which enables the machine to use double edged cutters). All three rotors are driven together by a single drive belt 32 which runs over their respective driven pulleys 22, 23, 24 and over a driving pulley 34. The driving pulley 34 is keyed onto the lower end of a vertical output shaft 35 of a right angle gearbox 36 as shown in Fig. 3. This gearbox (the outline of which is shown in phantom in Fig. 1) has a horizontal input shaft 38 which, during use of the pasture topper, faces forwardly.The pasture topper is fitted with hitch points 40, 42 by which it can be attached to the three point linkage of an agricultural tractor and when so attached the rear power take off of the tractor can be connected to the input shaft 38 of the gearbox 36 by means of a conventional telescopic coupling shaft with universal joints.

The hitch points 40 attach to the side arms of a tractor's three point linkage while the hitch point 42 has attached to it an upstanding pillar to the top of which are attached both the top link of the tractor's three point linkage and a bar extending across to the attachment point 44 at the trailing edge of the pasture topper. This arrangement, which is known per se, enables the pasture topper to be lifted off the ground by the tractor when not in use. The hitch points 40, 42 are somewhat off set relative to the centre line of the pasture topper. In consequence the pasture topper projects to one side of the tractor which is convenient for cutting close to hedges.

The driving belt is a conventional V belt. Its V shaped face 46 engages the driving pulley 34 and the two outer driven pulleys 23, 24 which accordingly are provided with the conventional V shaped groove which receives the belt and grips it as it passes round them. The central driven pulley 22, however, has a plain cylindrical form with flanges above and below. This is engaged by the flat back surface 48 of the belt. The directions of belt travel and rotation are indicated in Fig. 1 by arrows.

The central pulley 22 which is engaged by the flat back of the belt, and therefor does not have the benefit of gripping engagement with the V of the belt, immediately precedes the driving pulley 34 in the direction of belt travel and accordingly the central rotor is driven by the part of the belt which is under greatest tension. The portion 50 of the belt is necessarily also under greater tension than when stationary since this part is transmitting drive to the two outer pulleys 23, 24. The substantial amount of tension in the portion of the belt contacting the pulley 22 assists in driving this pulley and hence the central rotor using the back 48 of the belt.Also, it will be seen from Fig. 1 that the pulleys are arranged in such a way that the back of the belt contacts the central driven pulley over a large arc of contact which is something in the region of 235 . This considerably enhances the frictional engagement between the belt and this pulley, and also assists in driving this pulley by means of the back of the belt.

To adjust the tension of the belt it is arranged that the gear box 36 and driving pulley 34 are bodily movable in the lateral direction indicated by the double headed arrow 52 in Fig. 1. The amount of movement necessary for adjustment of belt tension is not sufficient to reduce seriously the arc over which the back 48 of the belt contacts the central driven pulley 22.

The arrangement shown by Fig. 1 and just described is economical in construction since it employs only a single drive belt (thereby making it uncessary to employ a multigrooved driving pulley on the gearbox output shaft) and also avoids the complication of additional jockey pulleys for adjustment of belt tension thereby giving a particularly simple and economical construction.

Fig. 3 shows a possible arrangement for mounting the gearbox 36 and driving pulley 34 so that belt tension can be adjusted by bodily movement of them. Two angle members 60 are mounted so as to be fast with the box section member 10 and the main structure of the machine generally but to lie above the run of the V belt 32. Four threaded studs 62 projecting upwardly from the members 60 pass through slots 64 in a flat plate 66 and carry nuts 68 which when tightened clamp the plate 66 against the members 60. The gearbox 36 is bolted firmly to the plate 66.

Thus the gearbox 36, its horizontal input shaft 38 its vertical output shaft 35 the driving pulley 34 on the lower end thereof and the plate 66 can all slide laterally as a single unit when the nuts 68 are slackened off. An adjusting screw 70 passed through a tapped hole in a cross bar 72 fast with the angle members 60, bears on an abutment 74 welded to the plate 66. To tighten the belt the nuts 88 are slackened and the screw 70 turned so as to urge the abutment 74 and with it the gearbox 36 and pulley 34 away from the cross bar 72 in opposition to the belt tension, so tightening the belt. Turning the screw 70 the opposite way allows the belt 32 to slacken. When a desired belt tension is reached the nuts 68 are tightened to clamping the plate 66 and hence the gearbox 36 and pulley 34 in place.

CLAIMS (20Aug1980) 1. An agricultural pasture topper, rotary mower or tedder having three cutting or tedding rotors distributed across the transverse width of the machine, each rotor being arranged to rotate around a generally upright axis and driven by means of a pulley or sprocket on that axis, characterised in that the central rotor is arranged to rotate in the opposite sense to the other two, all three rotors being driven by a single driving belt or chain passing over the said driven pulley or sprocket of each rotor and also over a driving pulley or sprocket, provision being made for adjustment of the tension of the belt or chain by movement of the axis of the said driving pulley or sprocket.

2. An agricultural machine according to Claim 1, wherein the said driving pulley or sprocket is fast with a vertical output shaft of a gearbox having a horizontal input shaft connectable to the rear power take off of an agricultural tractor, adjustment of the tension of the belt or chain being effected by lateral movement of the gearbox and said driving pulley or sprocket together.

3. An agricultural machine according to Claim 1 or Claim 2, wherein the belt or chain is arranged to run off the driving pulley or sprocket then around the driven pulley or sprocket of an outer one of the rotors, then around the driven pulley or sprocket on the other outer rotor, then around the driven pulley or sprocket on the central rotor and finally back to the driving pulley or sprocket, the face of the belt or chain which is radially inwards on the driving pulley or sprocket, and the two outer driven pulleys or sprockets being radially outward as it passes around the central driven pulley or sprocket.

4. An agricultural machine according to Claim 3 wherein the drive is by means of a V belt, the V shaped face of the belt engaging the driving pulley and outer driven pulleys and the flat back of the belt engaging the central driven pulley.

5. An agricultural machine according to Claim 4 wherein the central driven pulley has a right cylindrical surface.

6. An agricultural machine according to Claim 5 wherein the pulley includes a flange at each edge of the cylindrical surface.

7. An agricultural machine according to Claim 4 or Claim 5 wherein the back of the belt is in contact with the central driven pulley over an arc of at least 220 .

8. A pasture topper substantially as herein described with reference to the accompanying drawings.

CLAIMS (8 Dec 1980) 1. An agricultural pasture topper, rotary mower or tedder having three cutting or tedding rotors distributed across the transverse width of the machine, each rotor being arranged to rotate around a generally upright axis and driven by means of a pulley or sprocket on that axis, characterised in that the central rotor is arranged to rotate in the opposite sense to the other two, all three rotors being driven by a single driving belt or chain passing over the said driven pulley or sprocket of each rotor and also over a driving pulley or sprocket, the belt or chain being arranged to pass over the driving pulley or sprocket as it passes between the driving pulleys or sprockets of the central rotor and one outer rotor, the axis of the driving pulley or sprocket, as regards its position relative to the transverse direction of the machine, lying substantially within the width between the axes of the driven pulleys or sprockets of the central rotor and the other outer rotor, and provision being made for adjustment of the tension of the belt or chain by movement of the axis of the said driving pulley or sprocket.

3. An agricultural machine according to Claim 1 or Claim 2, wherein the belt or chain is arranged to run off the driving pulley or sprocket then around the driven pulley or sprocket of the said one outer rotor, then around the driven pulley or sprocket on the other outer rotor, then around the driven pulley or sprocket on the central rotor and finally back to the driving pulley or sprocket, the face of the belt or chain which is radially inwards on the driving pulley or sprocket and on the two outer driven pulleys or sprockets being radially outward as it passes around the central driven pulley or sprocket.

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Claims

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pulley or sprocket together.

3. An agricultural machine according to Claim 1 or Claim 2, wherein the belt or chain is arranged to run off the driving pulley or sprocket then around the driven pulley or sprocket of an outer one of the rotors, then around the driven pulley or sprocket on the other outer rotor, then around the driven pulley or sprocket on the central rotor and finally back to the driving pulley or sprocket, the face of the belt or chain which is radially inwards on the driving pulley or sprocket, and the two outer driven pulleys or sprockets being radially outward as it passes around the central driven pulley or sprocket.

4. An agricultural machine according to Claim 3 wherein the drive is by means of a V belt, the V shaped face of the belt engaging the driving pulley and outer driven pulleys and the flat back of the belt engaging the central driven pulley.

5. An agricultural machine according to Claim 4 wherein the central driven pulley has a right cylindrical surface.

6. An agricultural machine according to Claim 5 wherein the pulley includes a flange at each edge of the cylindrical surface.

7. An agricultural machine according to Claim 4 or Claim 5 wherein the back of the belt is in contact with the central driven pulley over an arc of at least 220 .

8. A pasture topper substantially as herein described with reference to the accompanying drawings.

CLAIMS (8 Dec 1980)

1. An agricultural pasture topper, rotary mower or tedder having three cutting or tedding rotors distributed across the transverse width of the machine, each rotor being arranged to rotate around a generally upright axis and driven by means of a pulley or sprocket on that axis, characterised in that the central rotor is arranged to rotate in the opposite sense to the other two, all three rotors being driven by a single driving belt or chain passing over the said driven pulley or sprocket of each rotor and also over a driving pulley or sprocket, the belt or chain being arranged to pass over the driving pulley or sprocket as it passes between the driving pulleys or sprockets of the central rotor and one outer rotor, the axis of the driving pulley or sprocket, as regards its position relative to the transverse direction of the machine, lying substantially within the width between the axes of the driven pulleys or sprockets of the central rotor and the other outer rotor, and provision being made for adjustment of the tension of the belt or chain by movement of the axis of the said driving pulley or sprocket.

3. An agricultural machine according to Claim 1 or Claim 2, wherein the belt or chain is arranged to run off the driving pulley or sprocket then around the driven pulley or sprocket of the said one outer rotor, then around the driven pulley or sprocket on the other outer rotor, then around the driven pulley or sprocket on the central rotor and finally back to the driving pulley or sprocket, the face of the belt or chain which is radially inwards on the driving pulley or sprocket and on the two outer driven pulleys or sprockets being radially outward as it passes around the central driven pulley or sprocket.