NZ533076A - Device attached between a tractor and a grass mowing machine which permits the mowing machine to be trailed rather than attach directly to the rear of the tractor - Google Patents

Abstract

A device for introduction between a commercial mowing machine B and tractor A which allows the mowing machine B to be trailed behind the tractor A. The device includes means for lifting the mowing machine B clear of the ground and carrying the majority of the weight of the mowing machine when it is lifted clear of the ground, wheels to enable transportation of the mowing machine B when it is not in operation, means for adjusting a centre of gravity such that a downward force is applied to a towing attachment when the mowing machine B is raised for transportation and means to position the mowing machine B to allow easy access to the underside of the machine B.

Description

Pat. 5 NEW ZEALAND Patents Form No. 5 533078 INTELLECTUAL PROPERTY OFFICE OF N.2.

MAV 2006 RECEIVED PATENTS ACT 1953 COMPLETE SPECIFICATION (To be furnished in Duplicate) Where priority as provided by subsection (2) or (3) of section 11 of the Patents Act 1953 is desired in respect of one or more provisional specifications, quote number or numbers and date or dates N0 533076 n„<- 24 May 2004 (a) Insert title of Invention. (a) DEVICE ATTACHED BETWEEN A TRACTOR AND A GRASS MOWING MACHINE WHICH PERMITS THE MOWING MACHINE TO BE TRAILED RATHER THAN ATTACH DIRECTLY TO THE REAR OF THE TRACTOR. (b) State (in full) name, address and nationality of applicant or applicants as in application form (b) We, TRIMAX INDUSTRIES LIMITED, of 70 Maleme St, PO Box 2150 Tauranga 3001, New Zealand, a 100% New Zealand owned company, (c) Here begin full description of invention. The continuation of the specification should be upon paper of the same size as this form, on one side only with the lines well spaced and with a margin of 2.5cm on the left hand side of the paper. The completion of the description should be followed by the words "What 1 (or we) claim is" after which should be written the claim or claims numbered consecutively (see note below). The specification and the dup- iicaie thereof must signed at the end. be HEREBY declare the invention, for which X/we pray that a patent may be granted toifiS/us and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a device to be introduced between a tractor or other suitable prime mover and a grass mowing machine that may otherwise NOTE. The claims must relate to a single invention, must be clear and succinct, and must be fairly based on the matter disclosed in the specification. They should form in brief a clear statement of that which constitutes the invention. Applicants should be careful that their claims include neither more nor less than they desire to protect by their patent. Any unnecessary multiplicity of claims or prolixity of language should be avoided.

Claims should not be made for the efficiency or advantages of the invention. attach directly to the rear of a tractor or prime mover.

Commercial mowing machines that are too large to be operated by a pedestrian are typically attached directly to the rear of tractors. A tractor supplies power to operate the cutting blades, tractive effort to propel the mowing machine along the ground while operating, a means of lifting the mowing machine clear of the ground, and the means to transport the machine between jobs. The type of mowing machine typically intended for use with the invention may be a multi-spindled rotary mower or a flail mower equipped with front-and-rear rollers or wheels, or a combination of rollers and wheels, but the invention may also be suitable for use with other machines or devices that may otherwise attach to the rear of a tractor or prime mover.

A mowing machine fixed to the rear of a tractor is not ideally suited for manoeuvring around obstacles such as trees, particularly where there are low hanging branches projecting over the grass that needs to be cut. Commercial mowing operators frequently need to use additional equipment in order to mow uncut grass around obstacles or in confined areas.

Due to the high duty cycle requirements of commercial mowing operations and the severity of the conditions they are frequently required to operate in, commercial mowing machines must be very robust. This often means that a tractor capable of supplying sufficient power to adequately operate the mowing machine while it is cutting grass may be too light to safely lift and transport the machine.

When a mowing machine is attached directly to a tractor, maintenance of the cutting system must usually be carried out from underneath. This can be extremely dangerous, resulting in serious injury or even death if the machine unexpectedly drops while this operation is in progress.

Some operators use prime movers other than tractors, such as four-wheel-drive vehicles, to tow mowing machines. These typically may have a power take-off suitable for powering the cutting blades, but may not have any means to allow the direct attachment of a mowing machine.

A previous attempt to overcome some of these difficulties was to fit simple "A" frame drawbar attachments to the front of standard tractor-mounted mowing machines. These allowed the mowing machines to be trailed behind the tractors, giving greater manoeuvrability. They also allowed small tractors to operate larger machines than they would be safely able to carry.

While greatly enhancing manoeuvrability, this method has some disadvantages. Because the mowing machine cannot be lifted, it can only be used in situations where the mowing machine can be trailed on its own rollers or wheels to travel between jobs. This makes it unsuitable for use where it is necessary to travel on public roads. Maintenance and cleaning of the mowing machine poses difficulties because there is no way of lifting it to gain access to the underside. Operators must have access to an inspection pit or some independent means of lifting the mowing machine.

The object of the present invention is to provide an interface between a tractor and a commercial mowing machine that will: 1) allow the mowing machine to be trailed behind the tractor so it can be manoeuvred more easily around obstacles, 2) carry the mowing machine independently from the tractor, thus allowing it to be used in conjunction with smaller tractors than would otherwise be required to safely lift it, 3) enable the mowing machine to be lifted clear of the ground, 4) provide wheels that enable the mowing machine to be towed along public roads, ) tilt the mowing machine forward into a more or less vertical position to provide safe and easy access to the cutting blades for inspection or maintenance, and 6) allow the mowing machine to be used in conjunction with a prime mover other than a tractor.

One preferred form of the invention will now be described with reference to the accompanying drawings, of which: Fig. 1 shows the front of the invention attached to the drawbar of a generic tractor (A) and a generic commercial mowing machine (B) fitted to the rear. This drawing shows the invention with the mowing machine lowered into the operating position.

Fig. 2 shows the invention with same tractor and mowing machine, but with the mowing machine raised into an almost vertical position for transport or for carrying out maintenance.

Fig. 3, Fig. 4 and Fig. 5 show the major component parts of the invention, namely: 1) a drawbar frame, 2) a tow hitch suitable for coupling to a tractor or prime mover, 3) a secondary frame, 4) a suitable hinge or hinged joints, ) an axle that forms the bottom of the secondary frame 6) two transport wheels, 7) mounting points for attaching linkage arms to the secondary frame, 8) two linkage arms, 9) stops that limit downward rotation of the linkage arms, ) guides that limit lateral movement in the linkage arms, 11) a hydraulic cylinder, linear actuator or similar, 12) stops that limit the forward rotation of the linkage arms when in the transport position, 13) stops that limit the forward movement of the mowing machine, 14) two spring steel rods, ) two cables or chains, and 16) a safety interlock mechanism.

Fig. 1 shows the following items, namely: 17) representative adapter brackets that provide mounting points on the mowing machine for the invention to connect to, and 18) a generic agricultural driveshaft with a telescopic centre section and universal joints at both ends to transmit rotational power from the tractor to the mowing machine if the mowing machine is of the type that requires such a connection.

The major components are constructed from steel or some other suitable material.

In the form shown, a drawbar frame 1 forms the foundation of the machine. A tow hitch 2 suitable for coupling to the rear of a tractor or other prime mover is fitted to the front of the drawbar frame.

A secondary frame 3 is attached to the rear of the drawbar frame 1 by a suitable hinge or hinged joints 4, the axis of which is substantially horizontal and is at right angles to the fore and aft centreline of the drawbar frame. The secondary frame 3 is able to pivot about the hinge 4 approximately 50 degrees either way from a substantially vertical position. The secondary frame extends below the hinge to provide an axle 5 to which is attached a pair of transport wheels 6, one on either side of the machine. The secondary frame 3 also extends above the hinge 4 to terminate in mounting points 7 for a pair of linkage arms, one on either side of the machine.

The linkage arms 8 attach to the mounting points 7 in a manner that allows them to pivot independently about a common axis parallel with that of the hinge 4. Guides 10 support the linkage arms 8 to prevent excessive sideways movement. Stops 9 are fitted to the linkage arms 8 or the secondary frame 3 to limit the rotation of the linkage arms in the downward direction when extended to the rear.

A hydraulic cylinder, linear actuator or similar device 11 is fitted between the drawbar frame 1 and the secondary frame 3 in a manner that can cause the secondary frame 3 to rotate about the hinge 4 within the limits of its movement as described previously. As the frame rotates to move the transport wheels to the rear, the linkage arm mounting points 7 and linkage arms 8 simultaneously move forwards. At some point the independent rotation of the linkage arms will be prevented by the stops 9 and the linkage arms will maintain station with the secondary frame 3 and pivot about the hinge 4. When the secondary frame reaches the limit of its movement in this direction the linkage arms bear against stops of some description 12 that prevent them from pivoting forward any further. In the form shown, these stops 12 also indirectly act to limit the movement of the secondary frame 3. This configuration is known as the transport position.

In order to enable the connection of the mowing machine to the device, the secondary frame 3 must be rotated in the direction that causes the transport wheels 6 to be at their most forward position. This configuration is known as the operating position.

The mowing machine is positioned directly behind the device. Suitable adapter frames or brackets 17 are fixed to the mowing machine in order to provide connection points for the linkage arms 8 on a common axis that is above and forward of the vertical centre of gravity of the mowing or similar machine. The linkage arms 8 typically connect to frames 17 with suitable pins in such a way as to allow the mowing machine some rotational movement in the longitudinal and transverse axes and a degree of translational movement in a vertical direction. This allows the mowing machine to move independently of the device in order to follow the contours of the terrain while operating.

If there is no part of the mowing machine suitably located, the adapter frames or brackets 17 provide a surface or surfaces which contact a stop or stops 13 attached to the secondary frame 3. The stop or stops must act at a level below the vertical centre of gravity of the mowing machine and prevent the front of the mowing machine from coming into contact with the transport wheels 6. In the form shown, the stops 13 consist of small wheels that will allow translational movement while in contact with their bearing surfaces as the mowing machine moves independently to follow contours in the terrain.

Some form of spring or springs and linkages, or similar devices, are connected between the adapter frames 17 and the axle 5 on the secondary frame 3 in order that the mowing machine will carry some or all of the weight of the transport wheels 6 when in the operating position. This weight transfer system must be adjustable to allow it to be set to suit the conditions the mowing machine is operating in. In the form shown, a pair of spring steel rods 14 is securely attached to the adapter frames or brackets 17 at points adjacent to the attachment point of the linkage arms 8. The spring rods 14 project forward to terminate above the axle 5 on the secondary frame 3. Suitable chains, cables or linkages 15 attach to the ends of the spring rods 14 and connect to the axle 5 on the secondary frame 3. The lengths of these cables, chains or linkages 15 are adjustable to govern the amount of force applied to the axle by the springs.

For normal operation the invention is set in the operating position with the transport wheels 6 as far forward as the movement of the secondary frame 3 will allow. The linkage arms 8 project rearwards in a substantially horizontal position and are attached to the mowing machine as described.

If the mowing machine requires rotational power to drive its operating parts a driveshaft 18 is connected between the power take-off of the tractor or prime mover and the transmission of the mowing machine. Alternatively the mowing machine may be powered by some other means such as hydraulic pressure.

The tractor or prime mover tows the invention with the mowing machine attached across the area to be mown or treated. The mowing machine can follow undulations in the contour of the area independently of the invention. Because the mowing machine is trailed behind the tractor or prime mover it turns within the turning radius of the tractor or prime mover. If the mowing machine is wide enough its inner side can even turn back on itself to partially overlap its original path when executing a 180-degree turn. This allows the tractor or prime mover to be driven around a tree, for example, keeping clear of low branches while the inner end of the mowing machine moves in a tight radius around the trunk.

When the mowing machine needs to be moved to another location, the secondary frame 3 is rotated into the transport position as described previously. This causes the linkage arms 8 to pull the mowing machine forward until it is prevented from going any further by the stop or stops 13. As the secondary frame 3 rotates further and the rotation of the linkage arms 8 is prevented by the stops 9, the mowing machine is lifted and rotated forward about the axis of the hinge 4 until it is in a substantially vertical position above the drawbar frame 1. As the mowing machine moves forwards the transport wheels 6 simultaneously move rearwards until they are behind the centre of gravity of the assembly. This causes a downward force to act on the tow hitch 2 where it connects to the tractor or other prime mover and ensures that the assembly can be towed safely.

The invention does not need extra locks to secure it either in the operating or transport positions as rotation of the secondary frame 3 in either direction requires that the entire assembly apart from the transport wheels and axle be lifted in order to transit one way or the other. If the hydraulic cylinder, linear actuator or similar device 11 were to fail the assembly would still be safe to operate in whichever position it was at the time of failure.

The invention carries almost all of the weight of the mowing machine in the transport position, thus allowing the use of smaller tractors or prime movers than would otherwise be required to carry the mowing machine. It also allows the use of other prime movers such as four-wheel-drive vehicles that may have a towing connection and some means of powering the machine but may not be equipped with mounting systems suitable for connecting directly to mowing machines.

When the mowing machine is coupled to the invention and lifted into the transport position it is more suitably positioned to enable work on the underside of the mowing machine than when coupled directly to a tractor or similar prime mover. Components are typically at a comfortable working height and, as long as the assembly remains attached to the tractor or prime mover, there is no danger of being crushed as a result of the machine dropping unexpectedly when working beneath it.

While the assembly remains attached to the tractor or other prime mover it is stable in both the operating and transport configurations. If detached from the tractor or prime mover while in the transport configuration the downward force on the drawbar 2 could be quite small, depending upon the exact configuration of the mowing machine and adapter brackets fitted. Consequently there is a danger that the assembly could be overbalanced, causing the mowing machine to topple rearwards while simultaneously rotating the drawbar assembly upwards. To prevent this possibility a safety interlock mechanism should be fitted. In the form shown an interlock mechanism 16 discourages the disconnection of the tow hitch 2 when it is attached to couplings typically found on standard tractors. Other interlock mechanisms could achieve the same results and may be required for other types of connections.

Claims (23)

WHAT WE CLAIM IS

1. A device to be introduced between a commercial mowing machine and a tractor or other prime mover to which the mowing machine may normally be attached directly, that allows the mowing machine to be trailed behind the tractor or prime mover, that provides a means of lifting the mowing machine clear of the ground, that carries the majority of the weight of the mowing machine when it is lifted clear of the ground, that incorporates wheels to enable the mowing machine to be transported while not operating, that adjusts the centre of gravity of the assembly to apply a downward force to the towing attachment when the mowing machine is raised for transport, and that can position the mowing machine in a manner that allows safe and easy access to the underside of the mowing machine.

2. A device as claimed in claim 1, including a horizontal draw bar frame attachable at the front to a tractor or prime mover.

3. A device as claimed in claim 2, including a secondary frame connected by means of a hinge to the rear of the draw bar frame referred to in claim 2 opposite the tractor or prime mover attachment point referred to in claim 2.

4. A device as claimed in claim 3, wherein the axis of the hinge referred to in claim 3 is substantially horizontal and is at right angles to a fore and aft centreline of the draw bar frame referred to in claim 2.

5. A device as claimed in claim 3, wherein the secondary frame referred to in claim 3 projects below the hinge referred to in claim 3 to form a transverse axle that is parallel with the hinge axis and carries two free wheeling transport wheels, one at either side of the device.

6. A device as claimed in any preceding claim, including two linkage arms.

7. A device as claimed in claim 6, wherein the secondary frame referred to in claim 3 projects above the hinge referred to in claim 3 to provide mounting points for the linkage arms referred to in claim 6, one on either side of the device.

8. A device as claimed in claim 7, wherein the forward ends of the linkage arms referred to in claim 6 connect to the secondary frame referred to in claim 3 at the mounting points described in claim 7 in a manner that allows the linkage arms to rotate independently about a common horizontal axis that is substantially parallel with the hinge referred to in claim 3.

9. A device as claimed in claim 6, including stops that limit the downward rotation of the two linkage arms referred to in claim 6.

10. A device as claimed in claim 3, wherein the secondary frame referred to in claim 3 is able to pivot about the hinge referred to in claim 3 through an arc of approximately 50 degrees either forwards or rearwards from a substantially vertical position.

11. A device as claimed in claim 3, wherein the secondary frame referred to in claim 3 can be caused to rotate in the manner described in claim 10.

12. A device as claimed in claim 10, wherein the configuration in which the secondary frame referred to in claim 3 is rotated as described in claim 10 to cause the transport wheels referred to in claim 5 to be as far forward as the movement of the secondary frame will allow will be referred to as the operating configuration.

13. A device as claimed in claim 10, wherein the configuration in which the secondary frame referred to in claim 3 is rotated as described in claim 10 to cause the transport wheels referred to in claim 5 to be as far rearward as the movement of the secondary frame will -7- allow will be referred to as the transport configuration.

14. A device as claimed in claim 6, wherein the rearward ends of the two linkage arms referred to in claim 6 attach to either side of a fore and aft centreline of a mowing machine by connection means which allow rotation about a common axis that is substantially parallel to the hinge referred to in claim 3 and is above and forward of the centre of gravity of the mowing machine while the mowing machine is in contact with the ground in its operating position.

15. A device as claimed in claim 12, including some form of spring connected between the mowing machine and the axle referred to in claim 5 in a manner that can be adjusted to cause the spring to carry part or all of the weight of the transport wheels referred to in claim 5 when the device in is the operating configuration as described in claim 12 and the mowing machine is in contact with the ground in its normal operating position.

16. A device as claimed in claim 5, including a stop or stops attached to the secondary frame referred to in claim 3 below the hinge referred to in claim 3 can contact some part or parts of the front of the mowing machine at a point or points below the centre of gravity of the mowing machine to prevent the mowing machine from moving forward sufficiently to contact the transport wheels referred to in claim 5.

17. A device as claimed in claim 16, wherein initial rotation of the secondary frame as described in claim 10 from the operating configuration as described in claim 12 towards the transport configuration as described in claim 13 will cause the secondary frame to pull forward on the linkage arms referred to in claim 6, causing the mowing machine to move initially forwards until the front of the mowing machine contacts the stop or stops referred to in claim 16.

18. A device as claimed in claim 17, wherein continued rotation of the secondary frame as described in claim 17 beyond the point at which the mowing machine contacts the stop or stops as described in claim 16 will cause the linkage arms described in claim 6 to contact the stops described in claim 9 and cause the linkage arms and mowing machine to maintain station with the secondary frame and rotate about the hinge referred to in claim 3.

19. A device as described in claim 18, wherein the synchronised rotation of the secondary frame and linkage arms and the mowing machine as described in claim 18 will result in the mowing machine being placed in a substantially vertical position above the hinge referred to in claim 3 when the secondary frame reaches the transport configuration as described in claim 13.

20. A device as claimed in claims 18 and 19, wherein rotation of the secondary frame from the operating configuration as described in claim 12 towards the transport configuration as described in claim 13 will cause the transport wheels described in claim 5 to simultaneously move rearwards about the hinge described in claim 3, thus moving to the rear of the centre of gravity of the mowing machine to cause a downward force to act on the front of the draw bar frame referred to in claim 2.

21. A device as claimed in claim 13, wherein the linkage arms referred to in claim 6 are prevented from pivoting forward about their mounting points as described in claim 8 when the device is in the transport configuration as described in claim 13.

22. A device as claimed in claim 12, wherein an interlock system may be included to discourage or prevent the drawbar attachment to the tractor or other prime mover referred -8- to in claim 2 from being disconnected unless the device is first positioned into the operating configuration as described in claim 12.

23. A device to be introduced between a commercial mowing machine and a tractor or other suitable prime mover substantially as described and as illustrated in the accompanying drawings. -9-