GB2254302A

GB2254302A - Trailer anti-theft device

Info

Publication number: GB2254302A
Application number: GB9106873A
Authority: GB
Inventors: Keith Austin
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-04-02
Filing date: 1991-04-02
Publication date: 1992-10-07
Also published as: GB9106873D0

Abstract

An anti-theft device for a trailer of an articulated lorry when unhitched from its tractor unit, in which the trailer landing legs 10 are locked in an extended position for supporting the trailer front end while the trailer is unhitched so as to prevent retraction of the leg lower part 10b into the upper tubular part 10a when unauthorised hitching to a tractor unit is attempted, comprising a secondary upper tube 20a fixed to the upper part 10a and a lower rod 20b fixed to the base of the lower part 10b and extending into the tube 20a. Tube 20a has holes 26 to receive a padlock 28 to prevent the rod 20b entering the tube 20a and also retraction of the leg lower part 10b. <IMAGE>

Description

TRAILER ANTI-THEFT DEVICE.

This invention relates to a trailer anti-theft device whereby a trailer of an articulated lorry combination is protected from theft when it is unhitched from the tractor unit and parked.

An advantage of an articulated lorry combination is that the trailer may be unhitched and parked separately while the tractor unit is driven away, either to haul another trailer or for other purposes. While it is parked the front of the trailer is supported on a pair of "landing" legs which are extensible. The legs are retracted when the trailer is hitched to the tractor and they are extended when the trailer is unhitched.

However, when a unhitched trailer is parked in a public place, particularly during the hours of darkness, it is vulnerable to theft since it is easy to hitch it up to another tractor unit and drive it away. The procedure of hitching a trailer to a tractor can be accomplished very speedily without attracting much attention, and indeed is a common and expected sight wherever trailers are parked.

Devices are known which can be attached to the trailer hitch king pin by which trailers are attached to tractors to prevent the king pin from engaging the hitch plate or so-called 'fifth wheel' on the tractor.

However, the king pin is located under the centre of the front of the trailer and is normally covered with large amounts of extremely dirty grease. Attaching such anti-theft devices is a dirty and difficult job, especially when undertaken in the dark.

According to the present invention there is provided an anti-theft means for a trailer of an articulated lorry when unhitched from its tractor unit comprising lockable means for anti-theft locking the trailer landing legs in an extended position for supporting the trailer front end while the trailer is unhitched so as to prevent retraction of the legs when unauthorised hitching to a tractor unit is attempted.

Embodiments of the invention will be described with reference to the drawings in which: Figure 1 depicts one form of anti-theft means, and Figure 2 depicts an alternative form of locking means.

In the embodiment shown in Figure 1 the landing legs 10 extend downwardly from the trailer chassis 12.

Conventionally the legs consist of a square or box section upper part lOa affixed to the trailer chassis and a lower part lOb, of a smaller box section, which is slideable in the upper part. Within the legs is a mechanism (not shown) for slideably extending and retracting the lower part with respect to the upper part, the mechanism being operated by means of a gearbox 14 and handle 16. In use the vehicle driver, prior to unhitching the trailer, will operate the mechanism to extend the legs until they contact the ground. The tractor fifth wheel securing catch is then released to allow the king pin to disengage from the fifth wheel and the tractor is driven away, whereupon the trailer front end settles onto the extended landing legs.When the trailer is re-hitched to the tractor the legs have to be retracted to provide ground clearance to allow the complete vehicle to be driven away Attached to the upper part lOa of the leg is a secondary upper part 20a comprising a stout metal tube, affixed externally to the upper part lOa by welded brackets 22. Attached to the lower part lOb is a secondary lower part 20b comprising a solid metal rod, affixed externally to the base of the lower part lOb by a welded foot piece 24, and extending partway into the tube 20a. When the lower part lOb of the leg is extended and retracted with respect to the upper part lOa the rod 20b will likewise slideably extend and retract with respect to the tube 20a. The tube 20a is provided with one or more holes 26 passing transversely through the tube adapted to receive a locking device such as a padlock 28.With the legs extended when the trailer is unhitched the locking means is simply inserted in the lowermost hole through which it will pass and locked. Any attempt to retract the legs without first unlocking and removing the locking device will be frustrated, because the locking device 28 prevents the rod 20b from entering further into the tube 20a, and even though the trailer is hitched there will still be a significant amount of weight on the legs in contact with the ground, rendering the complete vehicle undriveable. Because the locking means is part of the leg structure it is readily accessible and is not covered in grease. A further light, slideable tube can be provided over the tube 20a to protect the holes from weather and road dirt (not shown).

In the alternative embodiment shown in Figure 2 the box section part lOa of the leg is provided with the series of holes 26 which are positioned to avoid the internal mechanism 30 of the leg while at the same time allowing the inserted locking means 28 to engage the top of the lower part lOb, thus preventing it from being retracted into the upper part. The locking means may comprise a padlock with a long shackle, or a headed pin with a hole through which a padlock can be fastened once it is passed through the selected hole.

Claims

1. An anti-theft means for a trailer of an articulated lorry when unhitched from its tractor unit comprising lockable means for anti-theft locking the trailer landing legs in an extended position for supporting the trailer front end while the trailer is unhitched so as to prevent retraction of the legs when unauthorised hitching to a tractor unit is attempted.

2. An anti-theft means according to claim 1 wherein the lockable means comprises a secondary tubular upper part affixed externally to an upper part of the trailer leg and a secondary lower rod part affixed externally to a lower part of the trailer leg slideable in the upper part of the leg, the secondary lower rod part extending slideably into the secondary tubular upper part, the secondary tubular upper part being provided with one or more transverse holes adapted to receive a locking device to prevent the secondary lower rod part from entering into the secondary tubular upper part beyond the position of the locking device.

3. An anti-theft means according to claim 1 wherein the lockable means comprises one or more holes passing transversely through an upper tubular part of the trailer leg, the hole(s) being adapted to receive a locking device passed therethrough to prevent a lower part of the trailer leg from entering slideably into the upper part beyond the position of the locking device, the hole(s) being positioned so that the inserted locking device does not foul any internal extending mechanism of the trailer leg.

4. An anti-theft means for a trailer of an articulated lorry substantially as described with reference to Figure 1 or Figure 2 of the accompanying drawinas.