GB2121739A

GB2121739A - Adjusting suspension height

Info

Publication number: GB2121739A
Application number: GB08315059A
Authority: GB
Inventors: Trevor Webster Coe
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-06-01
Filing date: 1983-06-01
Publication date: 1984-01-04
Also published as: GB8315059D0

Abstract

An assembly for increasing the ground clearance of a vehicle, comprises a transom member 1 adapted to be mounted transversely at the rear of the vehicle; a pair of side members 2 adapted to be mounted at each side of the vehicle and to engage with the transom member whereby at least part of the weight of the vehicle can be supported by the side members, the side members each carrying a dependent elongated member 21 each carrying a rotatable wheel mounting means 22 whereby wheels can be mounted for supporting and driving the vehicle, the wheel mounting means being provided with driving means (not shown) whereby the motive force of the vehicle can be transmitted to the wheels upon the dependent members; and a pair of separate front wheel suspension extension legs 3 adapted to carry at their lower extremities front wheels for the vehicle, the extension legs each being rotatably mounted in a support casing 30 whereby the front wheels can be steered using the existing steering system of the vehicle, the support casings being provided with support means to limit fore and aft movement of the casing. <IMAGE>

Description

SPECIFICATION High ground clearance vehicle The present invention relate to an assembly for increasing the ground clearance of a vehicle, notably of an agricultural tractor.

In many farming operations it is necessary for a vehicle to pass through a field in which a crop is standing so as to treat that crop or to harvest it, eg.

to spray rape with agrochemicals or to harvest fruit from bushes. With conventional tractors, damage would be caused to the crop. It has therefore been proposed to raise the tractor higher off the ground to reduce this damage. However, prior proposals have often taken the form of a permanently converted tractor which finds limited general use; or have been complex and cumbersome contructions.

I have now devised a simple form of assembly which can be readily mounted upon a conventional tractor to increase its ground clearance and yet can be readily demounted when the tractor has completed the operation for which high ground clearance was needed.

Accordingly, the present invention provides an assembly for increasing the ground clearance of a vehicle, which assembly comprises a transom member adapted to be mounted transversely at the rear of the vehicle; a pair of side members adapted to be mounted at each side of the vehicle and to engage with the transom member whereby at least part of the weight of the vehicle can be supported by the side members, the side members each carrying a dependent elongated member; each of the dependent members carries a rotatable wheel mounting means whereby wheels can be mounted for supporting and driving the vehicle, the wheel mounting means being provided with driving means whereby the motive force of the vehicle can be transmitted to the wheels upon the dependent members; and a pair of separate front wheel suspension extension legs adapted to carry at their lower extremities front wheels for the vehicle, the extension legs each being rotatably mounted in a support casing whereby the front wheels can be steered using the existing steering system of the vehicle, the support casings being provided with support means to limit fore and aft movement of the casing but not being fixed or linked directly to one another except at or adjacent their upper ends.

For convenience, the present invention will be described with respect to a preferred form thereof for use on an agricultural tractor as shown in the accompanying drawings, in which: Figure 1 is a diagrammatic perspective view of the overall assembly; Figure 2 is a diagrammatic end view of a tractor rear end in place on the assembly; Figure 3 is a diagrammatic side view of the tractor of Figure 2; Figure 4 is a diagrammatic view of part of the assembly of Figure 1; and Figure 5 and 6 are diagrammatic vertical sections through parts of the assembly of Figure 1.

The assembly of the invention comprises a transom 1, two side members 2 and two separate front suspension extension assemblies 3. The transom 1 takes the form of a simple steel or other plate 10 or framework bolted or otherwise mounted across the rear of the tractor. It is preferred to form the transom 1 as a plate 10 which is bolted directly to the rear of the transmission housing and/or chassis of the tractor. It is also preferred to form apertures 11 in the transom 1 to accommodate the powertake off drive and three point linkage arms of the tractor so that these can be used when the transom is mounted on the tractor. The transom 1 extends laterally to provide mounting points for the side members 2.

Preferably, the transom 1 is wide enough to accommodate various widths of tractor and is provided with a series of laterally spaced mounting points so that the side members can be mounted thereon at various spacings according to the width of the tractor. Conveniently, the mounting points are provided by bolt holes 14, although supporting flanges and the like for the side members 2 may also be present.

The side members 2 each comprise a member which extends longitudinally along the tractor and is adapted to be mounted on the tractor, e.g. by bolts.

As shown in Figures 2 and 3, the side members 2 support the rear axle of the tractor and engage the transom 1, e.g. by being bolted thereto as described above. Preferably, the side members 2 extend well forward of the rear axle, but preferably not beyond the centre of gravity of the tractor, so that any upward thrust on the side members 2 from the dependent wheel supports described below is transferred into a downward thrust forward of the rear axle. Conveniently, the side members take the form of hollow box-like members which can serve as fuel tanks for the tractor, notably where the original fuel tank has been removed.Also, it may be preferred to form the side members 2 in two portions; a rear box portion supporting the rear axle of the tractor and a forward portion mounted, e.g. by bolting, welding or rivetting, on to the rear portion to transfer some of the thrust forward on the tractor.

Whilst it is preferred that the side members 2 can be removably mounted upon the transom 1 so that a common series of components can be readily assembled to fit different tractors, this need not be the case. Thus, part or all of the side members can form an integral part of the transom to form a generally U-shaped member designed to fit a specific tractor.

The side members 2 each carry a dependent wheel support 21 mounted, e.g. by welding, thereon. The support 21 is preferably of a box section constructin to provide the necessary strength and rigidity to minimise the need for bracing struts or gussets which could obstruct the free passage of plants under the tractor. The support 21 is of any desired length, depending upon the increase in ground clearance required. If desired, the length of members 21 can be made adjustable so that one common type of component will give various heights of ground clearance. Preferably, the supports 21 are mounted on the side members 2 substantially directly below or to the rear of the point where the side members are to pass or abut under the rear axle of the tractor to minimise any change in handling of the tractor steering.Whilst the supports can be configured so that they are substantially vertical legs when the assembly is mounted on the tractor, it will usually be desired that they are inclined to the rear as shown in Figure 3, to increase the wheel base of the tractor and thus the stability of the-raised tractor. They may also be splayed to increase the track of the tractor for the same reason.

The supports 21 carry at their free ends stub axles or other means for mounting wheels to carry the tractor. Preferably, the mounting means comprise a hub 22 carried in a roller, sleeve or other bearing on an axle assembly 23, the wheel being mounted on the hub 22 in the usual way. As described below, the hub 22 is rotated by a drive mechanism, preferably by a chain or belt drive from the rear axle hubs of the tractor. We therefore prefer that the longitudinal position of the axle assemblies 23 on the supports 21 be adjustable, e.g. by mounting them in screw adjustable slides, so that the drive means can be tensioned correctly. This also enables the vehicle to be driven in reverse which may not be possible where a jockey wheel tensioner is used.

It is particularly preferred to mount the axle assemblies 23 eccentrically in a rotatable bush 24 as shown in Figures 4 and 5, so that rotation of the bush varies the longitudinal position of the bearing assembly. This form of tensioning mechanism is of particular advantage in that it maintains the parallel configuration of the drive and driven shafts and also is less prone to damage by dirt than conventional screw tensioners. We believe that this form of tensioning device is new and the invention therefore also provides a belt or chain drive mechanism comprising a pulley or toothed wheel rotatably mounted on an axle mounted off centre on a bush-like memberjournalled in a mounting member, the bush-like member being rotatable so as to vary the position of the axle.

The bush-like member 24 can be a solid substantially cylindrical bush having the axle 23 mounted thereon with its longitudinal axis parallel to but offset from the longitudinal axis of the bush. Alternatively, as shown in Figure 5, the bush 24 can be provided by two transverse discs 50 forming the equivalent of the end faces of the cylinder and mounted off-centre on axle 51. The bush 24 is an interference fit within a corresponding bore or bush 52 through support 21 so that bush 24 is firmly held, but can be rotated. The bush 24 carries means for retaining it in a given anguiar orientation. For the form shown in Figure 5, this conveniently takes the form of a circular plate 53 of larger diameter than sleeve 52 and mounted over one end of bore 52. The plate is mounted by tightening bolts 54 onto one of the discs 50 housed within sleeve 52.The other disc 50 has a tapered periphery which fits against a corresponding taper to the mouth of sleeve 52. That disc also preferably has a spigot 55 which serves to centre the disc upon the sleeve 52. When bolts 54 are tightened, the bush assembly 24 is drawn into the sleeve 52 and the mating tapers are drawn tight, thus locking the bush 24 within the sleeve.

Such a form of tensioner is simple to construct and operate and maintains alignment of the axle 51 with the rear axle of the tractor. It also finds use in many other applications where a chain or belt drive is used, for example in the mounting of a bicycle rear axle or in the mounting of drive and support rollers in a conveyor belt transport system.

As indicated above, the hub 22 is driven from the tractor to propel the raised tractor. Whilst the drive could be via a gear or other drive from the power take-off drive of the tractor, it is preferred to drive hubs 22 from the hubs of the rear axle 25 of the tractors particularly preferred form of drive is by means of a chain and sprocket wheels 27 and 28 on the axle 25 and on hub 22. If necessary, the sprockets on axle 25 can be laterally offset from the end of axle 25 to accommodate different spacings between supports 21 due to different tractor widths. If desired, part or all of the drive system can be housed in a casing, e.g. in members 21, for safety and protection reasons.

The front suspension extension assemblies 3 each comprise a shaft-like member rotatable about a generally vertical axis. The member is linked to the steering mechanism of the tractor and transfers the action of the steering mechanism from the head of the assembly to its foot. Mounted at the foot of the assembly is a front ground wheel for the tractor. This can be provided by the original wheel of the tractor or by a replacement wheel of different size. The rotatable member conveniently takes the form of a substantially cylindrical shaft journalled in a supporting sleeve. The shaft can be mounted by means of roller or other bearings within the supporting sleeve, in which case the shaft may have a non circuiar cross-section. The longitudinal thrust of the weight of the tractor is carried by a suitable thrust bearing at the foot and/or head of the sleeve.

A preferred form of the front suspension extension assembly is shown in Figure 6 and comprises a generally cylindrical hollow casing 30 having at each end thereof a bush bearing adapted to receive a substantially co-axial longitudinal shaft 31 which can be formed as a single piece or in two or more parts for ease of assembly, if desired. Casing 30 has at or adjacent its upper end a radially protruding side arm 32 by which it can be mounted on or in place of the front axle beam ofthetractor. In orderto improve the lateral strength of the assembly when mounted upon the tractor, the arms 32 of both front suspension assemblies can be formed as a single unit which repiaces the axle beam of the tractor.

The upper end of shaft 31 protrudes from the casing and has mounted thereon the pivot arm lever 33 of the tractor steering system. This arm 33 is usually removably mounted on the king pin of the tractor's original steering mechanism by a conventional clamping fit. For present use, this arm can thus be removed from the original king pin and suspension of the tractor and fitted to the upper end of shaft 31 when the extension assembly 3 is fitted to the tractor.

The lower portion of shaft 31 protrudes from the base of casing 30 and carries a stub axle on which is mounted the front ground wheel. If desired, the lower portion of shaft 31 can be provided by the king pin 34 of the original steering assembly, which will also carry the front wheel hub and stub axle thereon.

The upper end of the king pin 34 is connected to the lower end of shaft 31 by any suitable means which ensures that the king pin rotates with the upper portion of shaft 31. For example, the connection could be via a dog tooth type clutch or, preferably, by means of a splined interconnection 35. Thus, the assembly 3 can be constructed at least in part from components already present in the original steering mechanism of the tractor with minimal alteration to those components.

The casing 30 is provided with struts to inhibit any substantial fore and aft movement of the casing, lateral movement of the assemblies being inhibitted by the mounting of the assemblies on the steering mechanism of the tractor and/or by the fixing of arms 32 to the front axle beam of the tractor. For example, a strut 40 can be mounted, e.g. by means of a ball or other flexible joint 41, to the foot of, or to a point approximately halfway up, casing 30. The other end of the strut can be mounted on the body of the tractor or can be attached to wheel support 21 or to side number 2. As indicated above, apart from the possible linkage between the two casings 30 via arms 32, the two side assemblies 3 are separate assemblies and are not linked transversely to one another. This reduces the presence of structures between the wheels of the raised tractor and hence reduces damage to crops passing under the tractor body.

The above assembly provides a simple and convenient means for raising the ground clearance of a tractor and can be simply mounted or demounted on a conventional tractor with minimal modification to the tractor.

Claims

1. An assembly for increasing the ground clearance of a vehicle, which assembly comprises a transom member adapted to be mounted transversely at the rear of the vehicle; a pair of side members adapted to be mounted at each side of the vehicle and to engage with the transom member whereby at least part of the weight of the vehicle can be supported by the side members, the side members each carrying a dependent elongated member; each of the dependent members carries a rotatable wheel mounting means whereby wheels can be niu̲nted for supporting and driving the vehicle, the wheel mounting means being provided with driving means whereby the motive force of the vehicle can be transmitted to the wheels upon the dependent members; and a pair of separate front wheel suspension extension legs adapted to carry at their lower extremities front wheels for the vehicle, the extension legs each being rotatably mounted in a support casing whereby the front wheels can be steered using the existing steering system of the vehicle, the support casings being provided with support means to limit fore and aft movement of the casing but not being fixed or linked directly to one another except at or adjacent their upper ends.

2. An assembly as claimed in claim 1 wherein the vehicle is an agricultural tractor.

3. An assembly as claimed in claim 2 wherein the transom member is provided bya plate member having apertures therein to accommodate the power take off drive and three point linkage arms of the tractor.

4. An assembly as claimed in any of the preceding claims wherein the side members extend forward of the rear axle of the vehicle but not beyond the centre of gravity of the vehicle.

5. An assembly as claimed in any of the preceding claims wherein the side members are formed as two sections the rear section being of hollow box section form.

6. An assembly as claimed in any of the preceding claims wherein the dependent side members are mounted upon the side members substantially directly below or to the rear of the piint at which the side members are to pass or abut under the rear axle of the vehicle.

7. An assembly as claimed in any of the preceding claims wherein the dependent side members ground wheels driving means at their feet by means of an adjustable mounting whereby the longitudinal location of the drive means on the members can be adjusted.

8. An assembly as claimed in any claim 7 wherein the drive means are mounted by means of a stub axle mounted off-centre in a rotatable bush member housed in a transverse bore in the member.

9. A drive means for use in the assembly of claim 8 which comprises a belt or chain drive to a pulley or tooted wheel rotatably mounted on an axle mounted off-centre on a bush-like memberjournailed in a mounting member, the bush-like member being rotatable so as to vary the position of the axle.

10. An assembly as claimed in any of the preceding claims wherein the front wheel suspension legs each comprises an elongated shaft rotatably housed in a sleeve member having at or adjacent its top ends a radiai arm whereby it is to be mounted on or in place of the front axle beam of the vehicle, the shaft extending at each end beyond the sleeve member and carrying at its lower end means for rotatably mounting a ground wheel for the vehicle.

11. An assembly as claimed in any of the preceding claims substantially as hereinbefore described with respect to and as shown in any one of the accompanying drawings.

12. A agricultural tractor having its ground clearance raised by being mounted on an assembly as claimed in any of the preceding claims.