GB2319504A - Road trailers - Google Patents

Abstract

A wheeled road trailer has a chassis (1) and two sets of road wheels (2, 3) at opposite ends. Each set of wheels has spaced apart parallel axles which are mounted on a bogie structure. The bogie structure has a linkage which permits independent vertical movement of the sets of wheels (2, 3). In use, one set of wheels (3) is in an uppermost retracted position and the other set (2) is in exclusive engagement with a road surface. The trailer also has a coupling at each end for engagement with a traction unit (4) to provide manoeuvrability of the trailer and facilitate hauling of the trailer in either direction when the sets of wheels (2, 3) are in their appropriate positions.

Description

ROAD VEHICLES This invention relates to wheeled road trailers.

With a conventional wheeled load-carrying road trailer of the kind having fixed (non-steerable) road wheels, the trailer has a chassis with a coupling beneath a forward end for pivotal mounting on a traction unit, and the road wheels are provided beneath a rearward end portion of the chassis.

With this known arrangement, limitations may be imposed on the positioning of the trailer for loading or unloading purposes and an object of the present invention is to provide a wheeled trailer of improved versatility.

According to the invention therefore there is provided a wheeled road trailer having a chassis with a respective coupling at each end and a respective set of road wheels beneath each end portion, each set of road wheels being independently retractable to leave the other set in exclusive engagement with a road surface.

With this arrangement, the trailer can be coupled to a traction unit selectively at either end. This facilitates manoeuvrability of the trailer for loading and unloading purposes, and provision can readily be made for loading and unloading through either or both ends and either or both sides.

The sets of road wheels may be mounted on bogies whereby retraction of the sets can be readily achieved by appropriate positional adjustment of the bogies.

Any suitable mechanism may be provided for retraction purposes and this may be operated mechanically and/or with pneumatic, hydraulic or electric power assistance.

The mechanism is preferably integrated in each set of wheels, particularly in the above mentioned bogie structure. Where power assistance is provided this may also involve integrated mechanisms or components and/or this may be achieved via connection to a power source on the trailer and/or on a traction unit or elsewhere.

The coupling may be of any suitable kind and conveniently may comprise the usual pivot plate beneath the trailer to fit on top of the usual king pin on the traction unit.

The trailer may incorporate swing-down legs at each end for ground engagement when the trailer is detached from the traction unit.

Alternatively, both sets of wheels may be extended into engagement with the ground surface to hold the trailer level.

At each end of the trailer there may be a rear assembly which is movable between a retracted position and an extended position, the assembly being extended when that end of the chassis is the rear end and otherwise being retracted. The rear assembly may comprise a bumper bar which may be mounted so as to swing or pivot between the respective positions.

Conveniently the trailer of the invention may be used with run-on trucks or wheeled pallets, and also the trailer may have an enclosed body which may have openable side panels such as gullwing doors. However, any suitable kind of load or loading system and body structure may be used.

The invention will now be described further by way of example only and with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic side sectional view of one form of a road trailer according to the invention; Fig. 2 is a diagrammatic plan view; and Fig. 3 is a diagrammatic cross-sectional view with loading doors shown open.

The trailer shown in Fig. 1 has a chassis 1 made from rigid streel members running longitudinally and transversely.

Beneath the central region of the chassis there are two sets of road wheels 2, 3 respectively at opposite end portions of the chassis 1.

The sets of road wheels 2, 3 are essentially identical and each has wheels mounted on two spaced apart parallel axleS which are mounted on a bogie structure. The bogie structure is mounted beneath the chassis 1 via a linkage which permits limited vertical movement of the bogie structure relative to the chassis 1 between an uppermost retracted position (as shown for the set of wheels 3 at the left of Fig. 1) and a lowermost extended position (as shown for the set of wheels 2 at the right of Fig. 1). The bogie structure is lockable in each such position.

The wheels are mounted via a suspension system and the vertically adjustable linkage may be incorporated in or form part of the suspension system (comprising for example pneumatic or hydraulic suspension units which can be contracted or expanded) or may be separate thereto.

A power operated system comprising an electric, pneumatic or hydraulic system, is connected to the vertically adjustable linkage, and may be arranged for connection to a power source and control mechanism (i.e.

an operating lever or switch or the like) elsewhere on the trailer or on a traction unit to be used with the trailer.

Beneath each end of the chassis 1 there is a respective pivot plate for mounting on a king pin of a traction unit (indicated in broken lines 4). At each end also there are connectors for linking electrical or pneumatic or hydraulic systems of the trailer to the traction unit.

At each end also there is a swing-down bumper assembly 5. This is movable between a retracted position at which it is locked beneath the chassis clear of the pivot plate, and an extended position at which it is locked vertically downwardly in an operative bumper position (as shown at the right of Fig. 1). The bumper may be manually movable between the respective positions or this may be power assisted.

The chassis 1 has mounted thereon a body 6 having side walls 7, a roof 8, end walls 9 and a central internal wall 10 dividing the body into two longitudinal compartments. The side walls 7 and roof 8 have a series of openable gullwing doors 11 as shown in Fig. 3. Doors are also provided in the end walls 9.

Within the body 6, two rows of wheeled pallet trucks 12 can be accommodated, each truck having a wheeled base with upstanding front and rear handles.

With this arrangement, the traction unit 4 can be coupled to the left end as indicated, with the left most set of wheels 3 and the left most bumper assembly 5 retracted, and the right most set of wheels 2 and bumper assembly 5 extended, as shown.

As and when required, this arrangement can be reversed. That is, the left most bumper assembly 5 and set of wheels 3 can be extended, and the right most bumper assembly 5 and set of wheels 2 can be retracted, whereby the traction unit 4 can be coupled to the right end of the chassis.

The trailer described has great versatility and permits different convenient arrangements for loading and unloading.

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only.

Claims (10)

1. A wheeled road trailer comprising a chassis with a respective coupling at each end and a respective set of road wheels beneath each end portion, each set of road wheels being independently retractable to leave the other set in exclusive engagement with a road surface.

2. A wheeled road trailer according to claim 1, wherein the sets of road wheels are mounted on bogies, said bogies being positionally adjustable for retraction of the wheels.

3. A wheeled road trailer according to claim 2, having a mechanism for retraction of the wheels which is integrated in each set of wheels.

4. A wheeled road trailer according to any one of claims 1 to 3, wherein a power assisted mechanism is provided for retraction of the wheels.

5. A wheeled road trailer according to any one of claims 1 to 4, wherein each said coupling comprises a pivot plate beneath the trailer to fit on top of a king pin on the traction unit.

6. A wheeled road trailer according to any one of claims 1 to 5, wherein swing down legs are incorporated at each end of the trailer for ground engagement when the trailer is detached from the traction unit.

7. A wheeled road trailer according to any one of claims 1 to 5, wherein both sets of wheels are extendable into engagement with the ground surface to hold the trailer level when the trailer is detached from the traction unit.

8. A wheeled road trailer according to any one of claims 1 to 7, wherein at each end of the trailer a rear assembly is provided which is movable between a retracted position and an extended position, said assembly comprising a bumper bar.

9. A wheeled road trailer according to any one of claims 1 to 8, wherein the trailer has an enclosed body which has openable side panels.

10. A wheeled road trailer substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.