AU739534B2 - Paddock roller - Google Patents

Description

-1- This invention relates to paddock rollers.

In New Zealand, as well as many other countries of the world, nearly every farm on which cattle are grazed would benefit from the use of a paddock roller. In the first place, after a paddock has been seeded (with grass seeds) it is beneficial to roll the seeds into the ground. However, possibly of greater importance, the ground on which cattle graze in wet conditions such as are commonly encountered in New Zealand is liable to become "pugged", which is to say that the surface of the ground under the pasture is broken up and softened as a result of being trampled on by the cattle. While still wet, the softened ground is unable to support the weight of a beast which stands on it or walks over it and indentations are formed underfoot as the beasts sink into the ground, high spots being left between the indentations. Pugged ground is disadvantageous for a number of reasons. First, it slows the rate at which excess surface water is able to run off, increasing the amount of time in which the ground remains water logged. The water retained in the indentations is prone to become stagnant.

Second, the surface area of pugged ground is increased. This has a tendency to increase the rate of moisture loss when dry conditions are subsequently experienced. Both of *these conditions reduce the rate at which the soil is able to grow pasture and the quality 0 20 of such pasture is also affected.

The accepted method of dealing with pugging is to roll it by means of a paddock roller towed behind a tractor. To make paddock rollers effective, reliance is conventionally placed entirely on the weight thereof. As a result, known paddock rollers are heavy, commonly weighing as much as three tonnes. This has a number of disadvantages. One disadvantage is that they cannot legally be towed behind a tractor on public roads unless they have a separate wheel arrangement on which they are supported. A second e disadvantage is that they cannot be towed up hill by low powered tractors. By the same token, the danger of towing a heavy paddock roller down hill is increased on account of the possibility of loss of control thereof. Yet another disadvantage of a conventional paddock roller is that, because of its weight, the tyres of the tractor which tows it make deep indentations in the ground which, as is well known, the roller is not usually capable of removing.

The applicant believes it to be a well known fact that many farmers prefer not to roll their pugged paddocks on account of the above noted disadvantages of the known December 1997/8952AU.D97/JW/iv paddock rollers.

One heavy type of known paddock roller comprises a roller drum of solid cement. In a second heavy type of known paddock roller, the roller drum comprises a hollow steel shell which is filled with water to increase its weight.

According to the invention there is provided a paddock roller assembly arranged to be hitched to a tractor provided with a three point hitch comprising two lower links and an upper link, the roller assembly comprising a roller drum, a connecting member for connecting the roller drum to the lower links of the three point hitch in such manner that pivotal movement of the connecting member in relation to the lower links tends to cause the roller drum to be raised or lowered relative to the tractor in use, and jacking means mountable between the connecting member and the upper link of the three point hitch in such a manner that actuation of the jacking means tends to bring about the pivotal movement of the connecting member and thereby to cause a downwardly acting force to be applied to the roller drum when the roller drum is on the ground, the connecting member being provided with an elastically flexible cantilever arm having a distal end which is connected to an anchor point on the tractor in use by connection means which limits the pivotal movement of the connecting member relative to the anchor point thereby to cause a reactive force to be applied to the tractor in use when the downwardly acting force is applied to the roller drum which reactive force tends to lift the tractor in use so that a portion of the weight of the tractor is transferred to the roller drum.

oo 25 A paddock roller assembly arranged in this manner has the advantage that the dead 0 0: weight of the assembly can be reduced since, in operation, the total downward force :i applied to the ground through the roller drum is the sum of the dead weight of the assembly and the said portion of the weight of the tractor which is transferred to the roller drum.

oooo According to one aspect of the invention, the connection means are such that, in use, the roller assembly is located at the rear end of the tractor.

*It is considered that this is likely to be the location which, as will be explained in 35 greater detail, will be most advantageous and the most commonly used.

According to one aspect of the invention, the roller assembly comprises a cross member on which the roller drum is rotatably mounted and which is provided with mounting means for connecting the jacking means to the upper link and for connecting the cross member to the lower links, the mounting means for connecting R the jacking means to the upper link being vertically spaced from the mounting means for connecting the cross member to the lower links, the arrangement being such that actuation of the jacking means causes the cross member to apply the downwardly acting force to the roller drum.

These arrangements have the effect that actuation of the jacking means can be arranged to cause the cross member to pivot about its longitudinal axis, the cross member in turn tending to move the roller drum downwardly. Since the roller drum is in contact with the ground when it is in its working position, it cannot move downwardly and the vertical component of the pivotal movement of the cross member sets up a reaction on the tractor which tends to lift the back of the tractor.

Advantageously, according to the invention, the distal end of the cantilever arm is located above the level of the anchor point, the connection means being arranged to apply the reactive force to the tractor in use by limiting upward movement of the connecting member relative to the tractor when the vertical distance between the distal end and the anchor point reaches a predetermined upper limit.

In one form of the invention, the connecting member is arranged to allow substantially unrestrained movement of the cantilever arm towards the anchor point.

Advantageously, the connecting member is arranged to allow variation of the upper limit of the vertical distance between the cantilever arm and the anchor point.

Advantageously, the connecting member comprises a chain.

oo o 25 If a chain is used as the connecting member, its length can easily be adjusted to enable oo the roller drum assembly to be mounted on tractors of differing sizes.

According to a further aspect of the invention, the anchor point is located at the swinging drawbar of the tractor.

ooo Advantageously, the cantilever arm is made up of a spring arrangement comprising at least one element of spring steel or similar material.

According to a further aspect of the invention, the connection means is provided with ooo 35 means for allowing a predetermined amount of lateral play between the roller assembly and the tractor such that, within predetermined limits, the rotational axis of the roller drum is not constrained to remain parallel to the rotational axes of the tractor wheels.

-4- Furthermore, the connection means may advantageously be provided with means for allowing a predetermined amount of upward and downward play between the roller assembly and the tractor such that, as long as the roller drum remains in contact with the ground, the roller drum is not constrained to remain at a constant level relative to the rear end of the tractor.

The purpose of providing for lateral play is to allow the roller drum to remain in contact with the ground along its entire length when an undulation in the ground causes one side of the tractor to rise or fall relative to the same side of the roller drum. The purpose of upward play is to allow the rear end of the tractor to fall relative to the roller drum (and thereby to remain in contact with the ground) when the roller drum traverses a ridge in the ground or the rear wheels traverse a depression in the ground. Similarly the purpose of downward play is to allow the roller drum to remain in contact with the ground when the rear wheels of the tractor traverse a ridge or the roller drum traverses a depression.

Lateral play may be achieved by providing that the yoke member is pivotably connected to each of the two lower link arms of the three point hitch and the jacking 20 member is mounted with its rear end pivotably connected to the yoke member and its front end pivotably connected to the top link of the three point hitch.

Preferably the joints at which the lower link arms are connected to the yoke member are positioned so that, in operation, the lower link arms can be set to float. They 0*.

25 consequently act simply as drawbars and do not constrain the vertical movement of the drawbar through its connection with the roller assembly. This promotes lateral play as well as upward and downward play which may be enhanced by providing that the o cantilever arm is elastically flexible, as already mentioned, and/or that its mounting S* arrangement on the cross member provides for a degree of elastic movement of the arm.

The advantage of these features is that the connection means can be adjusted to apply the correct lifting force to the back of the tractor just when the jacking member is fully extended. The apparatus can thus be set to operate with the jacking member only in this fully extended position and it is not necessary, in use, for the operator to continually adjust the jacking member.

December 1997/8952AU.D97/JW/iv In one form of the invention the cross member comprises a yoke member to which each end of the roller drum is rotatably mounted, and means for connecting the yoke member to the tractor.

According to one aspect of the invention, the yoke member is arranged to be connected to each of the lower links, and the jacking means includes a jacking member arranged to connect the yoke member to the top link and to be actuated to cause the yoke member to apply the downwardly acting force to the roller drum.

Advantageously, the yoke member is pivotably connected to each of the two lower links and the jacking member has a rear end which is pivotably connected to the yoke member and a front end which is pivotably connected to the top link.

According to a further aspect of the invention, the yoke member is provided at its ends with outer arms to the distal ends of which the roller drum is rotatably connected.

In one form of the invention the roller assembly includes means for driving the roller drum.

too In one form of the invention, the means for driving the roller drum includes a driving member and means for bringing the driving member to bear frictionally on at least one of the driven tractor wheels so as to be capable of being rotated thereby, and means for coupling the driving member to the roller drum.

*o *The roller assembly advantageously includes means to bring the driving member to bear frictionally on the roller drum, the roller drum being thus driven by the driving member when the driving member is rotated by the tractor wheel.

Location of the roller assembly behind the tractor has the effect that the lifting force which is applied to the tractor by the jacking means tends to lift the rear wheels of the tractor off the ground and hence to reduce the traction of the rear wheels. It is therefore considered that, in practice, at least in arrangements of the invention similar to those described by way of example with reference to Figure 1 of the accompanying drawings, use of the roller assembly is likely to be limited to four wheel drive tractors or at least tractors having driven front wheels.

December 1997/8952AU.D97/JW/iv -6- An alternative arrangement is to locate the roller assembly under the tractor, between the front and back wheels. However, this arrangement has certain disadvantages. It may not be possible to fit the roller assembly to many conventional tractors without the expense and complications of special additional componentry. Mounting and dismounting of the roller assembly on the tractor is likely to be time consuming and laborious. Furthermore, despite location of the roller assembly under the tractor, it is possible that the traction of the wheels may still be so reduced that only a four wheel drive tractor can be used.

The lifting force which is applied to the tractor should not, in any event, usually be so great that the rear wheels are lifted off the ground. This would tend to make the entire rig the tractor/roller combination) unstable. It would also tend to apply too much weight to the front wheels and increase the wear and tear on the rig.

0 One advantage of the roller assembly of the invention is that it typically weighs about 500 kg and is thus much lighter than conventional paddock rollers. It can thus be lifted o off the ground by the three point hitch of the tractor for transport.

20 A first embodiment of the invention is described by way of example with reference to Figure 1 of the accompanying drawings which is a somewhat schematic side view of a paddock roller assembly.

In the drawing the paddock roller assembly 10 comprises a roller drum 12 carried by a yoke member 14.

The drum 12 comprises a hollow cylindrical steel shell closed at its end by disc shaped end plates 16.

The yoke member comprises a hollow cylindrical steel cross beam 18 with arms which are mutually identical and are mounted one at each end of the cross beam. The distal ends of the arms carry bearings by means of which the drum 12 is mounted on the arms for rotation about the longitudinal axis X of the drum.

Two pairs of lugs 22 are welded to the lower face of the cross beam. The lug pairs are spaced at equal distances on either side of the longitudinal centre of the cross beam.

December 1997/8952AU.D97/JW/iv The distance between the lug pairs 22 is approximately equal to the average distance between the points on a tractor at which the lower link arms of the three point hitch are mounted and in fact the lug pairs 22 are provided with ball joints or other means of conventional design by which the distal ends of the lower link arms 24 can be connected to the respective lug pairs 22. This allows a degree of both lateral play and also upward and downward play of the cross beam relative to the lower link arms. As a result, within limits, the rotational axis X of the roller drum is not constrained to remain parallel to the rotational axes of the tractor wheels. Also, as long as the roller drum remains in contact with the ground, the rear end of the tractor is not constrained to remain at a constant level relative to the roller drum.

A single pair of lugs 26 are welded to the upper face of the cross beam at its longitudinal centre. The rear end of a double acting hydraulic ram assembly 28 is similarly connected through a ball joint or the like to the lug pair 26. The front end of the ram assembly 28 is connected to the eye of the top link connection 30 of the three point hitch.

:-Just to one side of the lug pair 26 a leaf spring assembly 32 is mounted on the cross 20 beam 18 by means of a trunnion plate assembly 34 defining a box formation in which the rear end of the spring assembly is fixed by means of a bolt 35. The spring assembly thus projects forward, cantilever fashion, from the box formation. The length of the spring assembly is chosen so that the front end thereof is located over the swinging drawbar 36 of the tractor. The front end of the upper blade of the spring assembly is 25 turned upwards as at 40 and is provided with vertical slots which are open at their upper ends. By this means the upper end of a link chain 38 is connected to the upper blade. A chosen one of the links in the chain is inserted in one of the slots. The chain is held "".captive in the slot as a result of the fact that the links adjacent the chosen link are .°[unable to pass sideways through the slot.

The lower end of the chain is connected to the swinging drawbar 36.

In operation, the assembly 10 is hitched to a conventional tractor which is preferably a four wheel drive tractor and is provided with a three point hitch. The assembly 10 is lifted by the three point hitch for transport to the paddock or meadow which is to be rolled. The three point hitch is then lowered so that the roller drum 12 rests on the December 1997/8952AU.D97/.N/jv ground with the lower links 24 of the three point hitch floating, i.e. able to move up and down without being constrained by the tractor. Assuming that the length of the chain has previously been adjusted, the ram assembly 28 is now extended for its full length.

In the arrangement shown in Figure 1, the yoke member is located substantially between the axis X of the roller drum and the rear end of the tractor. Consequently, as the ram assembly 28 extends, the yoke member 14 is caused to pivot clockwise about the axis X of the roller drum. During this movement, the yoke member moves upwardly and rearwardly, being restrained by its connection with the lower link arms and the roller drum 12. When the chain 38 becomes taut the upward component of the movement of the leaf spring assembly attached to the yoke member lifts the back of the tractor through the chain and the swinging drawbar.

The length of the chain will have been previously adjusted so that, when the ram assembly is fully extended, a desired amount of weight has been taken off the back of the tractor. This weight is of course transferred to the roller drum.

oo :The leaf spring assembly advantageously comprises a series of leaves, one or more of which can be removed to suit the roller drum assembly 10 to the weight of the tractor 20 on which the assembly is mounted. The stiffness of the spring assembly 32 ischosen so that, when the correct tension is applied to the chain with the complete rig in its working setting, the spring is still capable of yielding when there is a sudden increase in ***the tension in the chain. This increase is likely to occur when the rear wheels of the tractor drop into a depression in the ground or when the roller drum traverses an 25 upwardly projecting ridge in the ground. The ability of the spring to yield helps to ensure that, within limits, the rear wheels remain in contact with the ground.

Similarly, when the rear wheels of the tractor traverse a ridge in the ground (with a S* consequent tendency of the roller drum to be lifted off the ground) some of the tension in the spring assembly is released, helping to ensure that, again within limits, the roller drum remains on the ground and applies a constant downward force thereto.

The leaf spring assembly 32 can be raised or lowered within the box formation. Any space above or below the spring assembly within the box formation can be taken up by suitable packing pieces held in place by the bolt 35 so that the spring assembly is a tight fight in the box formation.

December 1997/8952AU.D97/JW/iv -9- The invention may be better suited to use with two wheel drive tractors by arranging that the roller drum is driven. In this arrangement, the apparatus is provided with at least one intermediate roller which is mounted on the apparatus in a working position in which, when the roller drum has been brought down onto the ground, the intermediate roller is located between the rear wheels of the tractor and the roller drum. In this position, the intermediate roller is in frictional contact with both the roller drum and the rear wheels so that the roller drum is thereby rotated by the rear wheels. The arrangement may comprise a single intermediate roller which is in contact with both of the rear wheels or, as shown schematically by way of example in Figure 2, a pair of spaced intermediate rollers 50, one in contact with each rear wheel 52. In the arrangement shown the intermediate rollers are carried on lugs 54 mounted on the cross beam 18. The intermediate rollers are positioned so that they are brought to bear on the rear wheels of the tractor when the yoke member 14 is pivoted clockwise by the ram assembly 28 to lift the rear end of the tractor as described above.

0° The intermediate rollers are desirably of rubber or the like.

In an alternative arrangement of a paddock roller assembly, the ram assembly 28 is 20 replaced by the conventional upper link of the three point hitch. A vertically disposed hydraulic ram is mounted between suitable lug pairs located on the cross beam and the forward end of the spring assembly 32. Extension of the ram when the roller drum is on the ground will, as in the arrangement shown in Figure 1, cause the front end of the spring assembly to lift and the chain 38 to take some of the weight off the rear end of 0 .0 25 the tractor.

It is not intended that the scope of a patent granted in pursuance of the application of oo*which this specification forms a part should exclude modifications and/or o *improvements to any matter described and/or illustrated herein which are within the scope of the invention as defined in the claims or be limited by such matter further than is necessary to distinguish the invention from the prior art.

S December 1997/8952AU.D97/JW/iv

Claims (14)

1. A paddock roller assembly arranged to be hitched to a tractor provided with a three point hitch comprising two lower links and an upper link, the roller assembly comprising a roller drum, a connecting member for connecting the roller drum to the lower links of the three point hitch in such manner that pivotal movement of the connecting member in relation to the lower links tends to cause the roller drum to be raised or lowered relative to the tractor in use, and jacking means mountable between the connecting member and the upper link of the three point hitch in such a manner that actuation of the jacking means tends to bring about the pivotal movement of the connecting member and thereby to cause a downwardly acting force to be applied to the roller drum when the roller drum is on the ground, the connecting member being provided with an elastically flexible cantilever arm having a distal end which is connected to an anchor point on the tractor in use by connection means which limits the pivotal movement of the connecting member relative to the anchor point thereby to cause a reactive force to be applied to the tractor in use when the downwardly acting force is applied to the roller drum which reactive force tends to lift the tractor in use so that a portion of the weight of the tractor is transferred to the roller drum.

2. A paddock roller assembly according to claim 1, in which the distal end ofthe cantilever arm is located above the level of the anchor point, the connection means 25 being arranged to apply the reactive force to the tractor in use by limiting upward movement of the connecting member relative to the tractor when the vertical distance between the distal end and the anchor point reaches a predetermined upper limit.

3. A paddock roller assembly according to claim 2, in which the connection means is arranged to allow substantially unrestrained movement of the cantilever arm towards anchor point.

4. 35 A paddock roller assembly according to claim 2 or claim 3, in which the connection means is arranged to allow variation of the upper limit of the vertical distance between the distal end and the anchor point.

A paddock roller assembly according to any one of claims 2 to 4, in which the SQ connection means comprises a chain.

6. A paddock roller assembly according to any one of claims 2 to 5, for use with a tractor provided with a swinging drawbar, the anchor point being located at the swinging drawbar.

7. A paddock roller assembly according to any one of claims 2 to 6, in which the cantilever arm comprises a spring arrangement made up of at least one element of spring material.

8. A paddock roller assembly according to any one of claims 1 to 7, in which the connection means is provided with means for allowing a predetermined amount of lateral play between the roller assembly and the tractor in use such that, within predetermined limits, the rotational axis of the roller drum is not constrained to remain parallel to the rotational axes of the tractor wheels.

9. A paddock roller assembly according to any one of claims 1 to 8, in which the connecting member comprises a cross member to which each end of the roller drum is rotatably mounted and means for pivotably connecting the cross member to each of the lower links of the three point hitch.

A paddock roller assembly according to claim 9, in which the jacking means includes a ".:."jacking member arranged to connect the cross member to the upper link and to be ""actuated to cause the cross member to apply the downwardly acting force to the roller drum. 000001 30

11. A paddock roller assembly according to claim 9 or claim 10, in which the cross member is provided at its ends with outer arms to the distal ends of which the roller drum is rotatably connected. 35

12. A paddock roller assembly according to any one of claims 1 to 11, including means for driving the roller drum.

13. A paddock roller assembly according to claim 12, in which the means for driving G the roller drum includes a driving member and means for bringing the driving member to bear frictionally on at least one of the driven tractor wheels so as to be capable of being rotated thereby, and means for coupling the driving member to the roller drum.

14. A paddock roller assembly according to claim 13, including means to bring the driving member to bear frictionally on the roller drum, the roller drum being thus driven by the driving member when the driving member is rotated by the tractor wheel. A paddock roller assembly according to any one of claims 1 to 14, substantially as herein described with reference to Figures 1 or 2 of the accompanying drawings. 0* 00 *see.: 0* S O0 S