GB2083783A

GB2083783A - Mounting of tractor axle assemblies on conventional road vehicles

Info

Publication number: GB2083783A
Application number: GB8029994A
Authority: GB
Original assignee: County Commercial Cars Ltd
Current assignee: County Commercial Cars Ltd
Priority date: 1980-09-17
Filing date: 1980-09-17
Publication date: 1982-03-31
Also published as: GB2083783B

Abstract

A road vehicle 1, having a chassis 3 with rear driving wheels 6 mounted on a conventional axle assembly 7 and leaf spring suspension 8, is converted for cross-country or agricultural use by replacement of the assembly 7 and suspension 8 by a tractor axle assembly 10, that is an assembly in which the brakes are fully enclosed in the axle housing together with the differential. The assembly 10 is clamped to the chassis 3 through resilient sleeves 24 so as to allow limited movement of the chassis relative to the assembly 10. <IMAGE>

Description

SPECIFICATION Mounting of tractor axle assemblies on conventional road vehicles This invention relates to the mounting of tractor axle assemblies on conventional rear wheel driven road vehicles.

The term "tractor axle assembly" is used in this specification to denote the type of rear axle assembly commonly used in tractors, in which the brakes are fully enclosed in the axle housing together with the differential.

The transport of loads in and around farms has conventionally been carried out by trailers towed by tractors. However, this method has the disadvantage that all of the load (in the case of four wheel trailers) or most of the load (in the case of two wheel trailers) is carried by the trailer wheels which are unpowered and tend to sink into soft ground causing deep ruts, thus damaging the land. At the same time, the comparatively unloaded tractor driving wheels have a tendency to spin. On the other hand, conventional road vehicles for load carrying have suspension systems unsuitable for travel across soft ground and are also liable to damage the land since their wheels are comparatively small and their tyres are inflated to high pressures.

The invention provides a conventional rear wheel driven road transport vehicle having a tractor axle assembly, as hereinbefore defined, mounted directly to the vehicle chassis by mounting means which allow limited movement of the chassis relative to the tractor axle assembly, to allow flexing of the chassis.

The invention also provides a rear wheel driven road vehicle which has been converted for crosscountry use by the replacement of its rear axle assembly and suspension by a tractor axle assembly as hereinbefore defined, the tractor axle assembly being mounted directly to the vehicle chassis by mounting means which allow limited movement of the chassis relative to the tractor axle assembly, to allow flexing of the chassis.

The invention further provides a method of converting a conventional rear wheel driven road vehicle for cross country use comprising the steps of demounting the existing rear axle assembly and its suspension and then mounting a tractor axle assembly, as hereinbefore defined, directly to the vehicle chassis by mounting means which allow limited movement of the chassis relative to the tractor axle assembly to allow flexing of the chassis.

The tractor axle assembly may be mounted semi rigidly to the chassis and the mounting means may comprise clamp means attached to the chassis and resilient material, the material being clamped around the tractor axle assembly by the clamp means.

A utility body may be mounted on the vehicle by a three position mounting so that the body does not inhibit flexing of the chassis. Preferably, one of the mounting positions is situated substantially on the neutral axis of the chassis and allows rotation of the body relative to the chassis at that position about an axis substantially coincident with the neutral axis.

The body may be mounted at two rear positions and at a forward position on the chassis on the neutral axis thereof, and the body may be mounted on the chassis at all three positions.

Alternatively, the body may be mounted at two rear positions directly on the tractor axle assembly and at a forward position on the chassis on the neutral axis thereof.

The body may be mounted by a universal joint at each of the three positions.

The body may be a tipper body mounted pivotally at the two rear positions for pivotal movement about a tipping axis, the vehicle comprising a ram for tipping the body mounted at one end on the chassis at the forward position and attached at the other end to the body.

Two embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows in side elevation the chassis and cable of a conventional road vehicle before conversion according to the invention; Figure 2 is a plan view of the chassis and cab of the vehicle of Figure 1 after conversion according to the invention; Figure 3 is a side elevation of the converted vehicle of Figure 2 having an open type body mounted thereon; Figure 4 is a rear elevation of the converted vehicle of Figure 3; Figure 5 is an enlarged sectional side elevation of part of the vehicle of Figure 3; Figure 6 is a partially sectional plan view of a second vehicle converted according to the invention having a tipper body mounted thereon; and Figure 7 is a side elevation of the converted vehicle of Figure 6.

Figure 1 shows in side elevation a conventional road vehicle 1 having a cab 2 mounted on a chassis 3. The chassis 3 is supported on front steerable wheels 5 and rear driving wheels 6, the latter being mounted on a conventional axle assembly 7 and leaf spring suspension 8.

The first step in the conversion of the vehicle 1 for cross-country or agricultural use is the removal of the existing axle assembly 7 and leaf spring suspension 8 from the chassis 3. A complete tractor axle assembly 10 having a housing 11, which fully encloses both a differential and disc brakes, is then mounted directly on the chassis as will be described hereinafter. The housing 11 comprises a central section 1 is and two outer sections 1 ib. A pair of large agricultural type wheels 12 are fitted to the half shafts 13 of the axle assembly 10. The wheels 12 may be inflated to comparatively low pressures, such as 12 to 20 pounds per square inch (about 83 to 138 kN/m2), so that they present a large area of contact with the ground, as shown in Figures 3 and 4.This provides a more resilient support for the vehicle and creates a low pressure contact with the ground, thus substantially decreasing the risk of damage to the ground.

Figure 2 shows in plan view the cab 2 and chassis 3 of the converted vehicle 1'. The chassis 3 comprises channel side members 15 connected by cross members 17, 18 and 19. The tractor axle assembly 10 is mounted on the chassis as shown in Figure 5. A mounting bracket 20 is attached to each side member 15 by welding, riveting or bolting. Each bracket 20 comprises a transverse clamp portion 21 to which is attached to clamp bracket 22 by nuts and bolts 23.

A sleeve 25 of resilient material such as moulded or compressed rubber, is clamped around each of the outer sections 11 b of the axle housing 11 between the bracket 12 and clamp portion 21. This "sandwich" type assembly provides a semi-rigid mounting of the tractor axle clamp assembly which will allow limited flexing of the chassis about its neutral, longitudinal axis.

Figures 3 and 4 show the vehicle 1' with an open type utility body 30 mounted thereon. In order not to inhibit flexing of the chassis about its natural longitudinal neutral axis, the body 30 has a three point mounting on the chassis, two rear points and a single forward point on the neutral axis. Each rear mounting comprises a support 31 welded to a respective bracket 20 and holding a resilient bearing 32 in which is located a rod attached to a bracket 33 which is fastened to the body 30. The forward mounting is similar to the rear mounting, comprising a third resilient bearing 32 but which is supported on the cross member 18. The bearings 32 permit rotation about longitudinal axes, the axis of the forward bearing being coincident with the neutral axis.

Universal joints or other spherical type joints may alternatively be used for mounting the body 30 in place of the supports 31, bearings 32 and brackets 33.

Figures 6 and 7 show another vehicle converted as described above but having a tipper body 40 mounted thereon instead of the open body 30. The body 40 is mounted at the rear by pivot brackets 41 which are rotatable on a transverse shaft 42 located in support brackets 43 which in this case form an integral part of the tractor axle assembly 10. The forward mounting of the body 40 is a universal coupling 45 connected to a hydraulic ram 44 for raising and lowering the body 40 as shown in ghost lines in Figure 7. the lower end of the ram 44 is attached to a transverse member 46 pivotally mounted in trunnions 47 secured to the side members 15 of the chassis.

An advantage of the above embodiments of the invention is that the higher axle height of the tractor axle assembly allows large agricultural type wheels to be fitted to the vehicle. These cause far less damage to agricultural soil than normal road tyres, particularly when inflated lightly. Thus the load to be carried is transmitted primarily to the large agricultural type wheels and the use of a trailer, with its inherent disadvantages, is obviated.

Another advantage of the embodiment is that the resilient mounting of the tractor axle assembly does not constrain the normal flexure of the chassis experienced for example when driving over rough ground. Neither is such flexure inhibited by the body since the latter is mounted at three points.

Claims

1. A conventional rear wheel driven road transport vehicle having a tractor axle assembly, as hereinbefore defined, mounted directely to the vehicle chassis by mounting means which allow limited movement of the chassis relative to the tractor axle assembly, to allow flexing of the chassis.

2. A rear wheel driven road vehicle which has been converted for cross-country use by the replacement of its rear axle assembly and suspension by a tractor axle assembly as hereinbefore defined, the tractoraxleassembly being mounted directly to the vehicle chassis by mounting means which allow limited movement of the chassis relative to the tractor axle assembly, to allow flexing of the chassis.

3. Avehicle as claimed in either Claim 1 or Claim 2 wherein the tractor axle assembly is mounted semi-rigidly to the chassis by the mounting means.

4. A vehicle as claimed in Claim 3 wherein the mounting means comprises clamp means attached to the chassis and resilient material, the material being clamped around the tractor axle assembly by the clamp means.

5. Avehicle as claimed in any preceding claim having a utility body mounted thereon by a three position mounting so that the body does not inhibit flexing of the chassis.

6. A vehicle as claimed in Claim 5 wherein one of the mounting positions in situated substantially on the neutral axis of the chassis, and allows rotation of the body relative to the chassis at that position about an axis substantially coincident with the neutral axis.

7. A vehicle as claimed in Claim 6 wherein the body is mounted at two rear positions and at a forward position on the chassis on the neutral axis thereof.

8. A vehicle as claimed in Claim 7 wherein the body is mounted on the chassis at each of the three positions.

9. Avehicle as claimed in either Claim 5 or Claim 6 wherein the body is mounted at two rear positions directly on the tractor axle assembly and at a forward position on the chassis on the neutral axis thereof.

10. A vehicle as claimed in any one of Claims 5 to 9 wherein the body is mounted by a universal joint at each of the three positions.

11. A vehicle as claimed in any one of claims 7 to 9 wherein the body is a tipper body mounted pivotabiy at the two rear positions for pivotal movement about a tipping axis, the vehicle comprising a ram for tipping the body mounted at one end on the chassis at the forward position and attached at the other end to the body.

12. A method of converting a conventional rear wheel driven road vehicle for cross country use comprising the steps of demounting the existing rear axle assembly and its suspension and then mounting a tractor axle assembly, as hereinbefore defined, directly to the vehicle chassis by mounting means which allow limited movement of the chassis relative to the tractor axle assembly, to allow flexing of the chassis.

13. A converted vehicle substantially as hereinb efore described with reference to and as shown in Figures 2 to 5 or Figures 2,6 and 7 of the accompanying drawings.