GB2170769A - Coupling of vehicles for towing - Google Patents

Abstract

Coupling together a tractor and a trailer for towing presents difficulties in aligning the vehicles so that an eye on the trailer can be connected to a hook on the tractor, or vice-versa. A trailer has a mounting 2 incorporating an automatic coupling device 5. A drawbar 4 having outer and inner eyes 6, 7 is slidable in a spherical bearing 3 in mounting 2. Lever 14 unlatches and lifts locking pin 13 to release eye 7 so drawbar 4 can be drawn out. With tractor and trailer suitably positioned the spherical and sliding bearing 3 allows drawbar 4 to be manoeuvred to engage eye 6 on rotatable hook 8 of the tractor. Reversing the tractor with the trailer brake applied closes drawbar 4 into mounting 2. The tapered nose of eye 7 is guided by guide plates 11 and corresponding inclined side walls into the automatic coupling device and pin 13 enters bore 12 to engage eye 7 and the latch secures pin 13. The spherical bearing 3 may be replaced, for road vehicle couplings, by a trunnion allowing pivotting about a vertical axis. <IMAGE>

Description

SPECIFICATION Coupling of vehicles for towing This invention relates to the coupling of vehicles for towing, to vehicles so coupled and to a coupling member therefor.

The invention is concerned with a vehicle combination of tractor and trailer wherein one vehicle, generally the tractor, is fitted with a hook and the other vehicle, generally the trailer, is fitted with an eye. One or other of the hook and eye is rotatable about an axis extending longitudinally of the respective vehicle to accommodate twisting of one vehicle relative to the other. Coupling together such a vehicle combination is done manually when the respective coupling elements (hook and eye) have been aligned. Such alignment presents considerable difficulty. On the one hand, there may be height differences between the vehicles dependant upon the laden state of each and, on the other hand, the lateral positioning of the vehicles to enable them to be coupled is difficult, especially with heavier trailers and multiple axle trailers.

According to one aspect of the present invention a coupling member for a vehicle comprises in combination a mounting, a bearing carried by the mounting, a drawbar slidable longitudinally in the bearing and a releasable automatic coupling device carried by the mounting, wherein the drawbar has a first coupling element on an outer end thereof adapted to be coupled to a second coupling element for towing purposes, and an eye on an inner end thereof adapted to cooperate with and be coupled to the automatic coupling device, the arrangement being such that with the automatic coupling device released the drawbar may be extended from the mounting for engagement of the first coupling element with said second coupling element and on closure of the draw bar into the mounting the eye is engaged by the automatic coupling device.

The coupling elements may conveniently comprise a hook and an eye.

The bearing may be arranged and mounted so as to be pivotable about at least one axis normal to the longitudinal axis of the drawbar whereby the extended drawbar and bearing can pivot so as to facilitate alignment and engagement of the first and second coupling elements.

The bearing is preferably a spherical bearing whereby the extended drawbar and bearing may pivot about vertical and horizontal axes and the drawbar may be moved axially in the bearing to facilitate alignment and engagement of the first and second coupling elements.

Guide means may be carried by the mounting adapted to guide the said eye towards alignment with the automatic coupling device.

According to another aspect this invention comprises a trailer vehicle having a coupling member as aforesaid at the front end thereof.

According to yet another aspect this invention comprises in combination a tractor vehicle having a coupling element (the second coupling element) at the rear end thereof for towing purposes and a trailer vehicle having a coupling member as aforesaid at the front thereof, the first coupling element of said coupling member being connected to the second coupling element and the eye being engaged by the automatic coupling device.

According to a further aspect of this invention a method of coupling a tractor vehicle having a coupling element (the second coupling element) at the rear thereof for towing purposes and a trailer vehicle having a coupling member as aforesaid at the front thereof comprises the steps of releasing the automatic coupling device (if engaged), extending the drawbar, manoeuvring one or both vehicles until the first coupling element can be engaged with the second coupling element and is so engaged and then causing the vehicles to close towards one another until the drawbar is closed and the eye is engaged by the automatic coupling device.

The invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a schematic plan view of a coupling member in the closed condition, Figure 2 is a schematic side view of the coupling member of Figure 1 engaged with a coupling element in the form of a rotatable hook and Figure 3 is similar to Figure 2 showing the drawbar inclined and partially extended.

Referring to the drawings, a coupling member 1 has a mounting 2 secured to or integral with the towbar of a trailer vehicle (not shown). A spherical bearing 3 is fitted in the front end of mounting 2. A drawbar 4 is slidable to and fro in the bearing 3.

An automatic coupling device 5 of known construction is secured in mounting 2.

The drawbar 4 has a first coupling element in the form of an eye 6 at its outer end which protrudes from mounting 2 and an eye 7 at its inner end within the mounting 2.

A tractor vehicle (not shown) has at its rear end a coupling element in the form of a towing hook 8 which is rotatable so as to accommodate relative inclination, or even over-turning, of either towed or towing vehicle relative to the other. The eye 6 (shown partly in section in Figures 2 and 3) is shown engaged on hook 8 which is fitted, as is usual, with a safety catch (not shown) to ensure retention of the eye.

The mounting 2 has inclined side walls 9 and inclined upper and lower guide plates 11 whose purpose is to guide the eye 7 into the automatic coupling device 5 when the drawbar 4 is closed into mounting 2.

The automatic coupling device 5 which is shown is of conventional commercially available construction having inclined upper, lower and side plates to receive the eye 7 and guide it into the position in which its bore, indicated at 12, is in alignment with the locking pin 13. It will be seen that the eye 7 has a tapered nose. As this enters the coupling device 5 it engages the tapered end of locking pin 13, shown latched in its raised position, and pushes it upwardly. This automatically releases the latch so locking pin 13 enters and passes through bore 12 when this is aligned. The latch engages, due to the spring bias on the release lever 14, to secure the locking pin 13 in its lowered position, retaining the eye 7 locked in the automatic coupling device 5.

The method of coupling a tractor vehicle to a trailer vehicle fitted with coupling member 1 will now be described. The tractor vehicle is maneouvred so that its hook 8 is as close to the eye 6 of coupling member 1 as is practicable. The lever 14 is operated to release and raise the locking pin 13 so that drawbar 4 can be withdrawn from the automatic locking device 5. The pin 13 is latched in its raised position. Drawer 4 is pulled out as far as is necessary and the spherical bearing 3 allows it to be orientated so that eye 6 can be engaged on hook 8 without having to adjust the trailer vehicle vertically or laterally. The safety catch is applied on hook 8 to retain eye 6. Whilst the trailer brakes are applied the tractor vehicle is gently reversed towards the trailer.As this occurs the drawbar 4 is closed into mounting 2, eye 7 is guided into automatic coupling device 5 and locking pin 13 enters the bore 12 in the eye 7 and the locking pin is secured automatically by the latch. The vehicles are now coupled together for towing of one by the other.

In the practice of this invention commercially available standard eyes, bearing and automatic coupling device are used whereby an advantageous and relatively inexpensive coupling member is provided for use with a commercially available standard hook.

Whilst this invention has been described with reference to the use of a spherical bearing 3, a trunnion mounted bearing giving freedom to pivot about one axis normal to the axis of the drawbar 4, may be used if desired. This may be used, for exampie, for on the road vehicles wherein vertical alignment of hook 8 and eye 6 presents no problems (for example a single axle type trailer) and the bearing facilitates lateral alignment only for coupling purposes. It will also be appreciated that the coupling element on the towing vehicle, as hook 8, may be fixed and the coupling element on the coupling member, as eye 6, may be rotatable.

The eye may be provided on the towing vehicle and the hook on the coupling member if desired.

Claims (11)

1. A coupling member for a vehicle comprises in combination a mounting, a bearing carried by the mounting, a drawbar slidable longitudinally in the bearing and a releasable automatic coupling device carried by the mounting, wherein the drawbar has a first coupling element on an outer end thereof adapted to be coupled to a second coupling element for towing purposes, and an eye on an inner end thereof adapted to co-operate with and be coupled to the automatic coupling device, the arrangement being such that with the automatic coupling device released the drawbar may be extended from the mounting for engagement of the first coupling element with the second coupling element and on closure of the drawbar into the mounting the eye is engaged by the automatic coupling device.

2. A coupling member as claimed in claim 1 wherein the bearing is arranged and mounted so as to be pivotable about at least one axis normal to the iongitudinal axis of the drawbar whereby the extended drawbar and bearing can pivot so as to facilitate alignment and engagement of the first coupling element with the second coupling element.

3. A coupling member as claimed in claim 2 wherein the bearing comprises a spherical bearing.

4. A coupling member as claimed in any one of claims 1 to 3 wherein the mounting incorporates guide means adapted to guide the eye towards alignment with the automatic coupling device.

5. A coupling member as claimed in claim 4 wherein the eye incorporates a tapered nose adapted to co-operate with the guide means and the automatic coupling device to facilitate guidance of the eye into the automatic coupling device for engagement thereby.

6. A trailer vehicle fitted with a coupling member as claimed in any preceding claim.

7. In combination a tractor vehicle having a second coupling element and a trailer vehicle as claimed in claim 6, the first coupling element of said coupling member being connected to the second coupling element and the eye being engaged by the automatic coupling device, one of said first and second coupling elements being rotatable.

8. A method of coupling a tractor vehicle having a second coupling element at the rear thereof for towing purposes and a trailer vehicle as claimed in claim 6 comprising the steps of releasing the automatic coupling device (if engaged), extending the drawbar, manoeuvring one or both vehicles until the first coupling element can be engaged with the second coupling element and is so engaged, and causing the vehicles to close towards one another until the drawbar is closed and the eye is engaged by the automatic coupling device.

9. A coupling member as claimed in any one of claims 1 to 5 wherein the first coupling element is an eye.

10. A coupling member as claimed in claim 9 wherein the said eye is rotatable about an axis extending longitudinally of the drawbar.

11. A coupling member for a vehicle substantially as described herein with reference to the accompanying drawings Figures 1 to 3.