WO2004030953A1

WO2004030953A1 - Trailer eye lock

Info

Publication number: WO2004030953A1
Application number: PCT/GB2003/000126
Authority: WO
Inventors: Danny Tom Johnstone
Original assignee: Danny Tom Johnstone
Priority date: 2002-10-03
Filing date: 2003-01-15
Publication date: 2004-04-15
Also published as: AU2003201668A1; GB2393699A; GB0222877D0; GB2393699B

Abstract

An anti-theft device for blocking the towing eye of a drawbar, comprising a lower flanged element (4), which is inserted upwards into hole (2) of the towing eye (1). The upper flanged element is inserted downwards through hole (2) where dowel pin (9) attached to it mates with corresponding hole (10) in the lower element. The two elements are pushed together fully and fastened together with bolt (12). A security lock (6) is inserted in the hole (19) machined in element (5), in order to prevent access to the head of bolt (12). When the key (3) is turned to the locked position, the locking pin (13) enters an annular recess (7). The lock barrel is gripped by an 'O' ring (14) fitted into recess (18). The lock barrel (6) is free to turn once in the locked position.

Description

TRAILER EYE LOCK

This invention relates to an anti-theft device for trailers or trailed equipment such as compressors, plant equipment and agricultural implements which are coupled to the towing vehicle by way of a drawbar incorporating a towing eye, as distinct from those using a ball hitch.

The theft of trailers and other types of wheeled equipment has been a major problem to many companies and individuals for many years. Although some thefts involve the equipment being lifted by crane, or other means, onto a lorry, most thefts involve the equipment simply being hitched to a vehicle and driven off.

Many attempts have been made in the past to prevent this type of theft, usually by trying to block or cover the towing eye with a lockable device to prevent use. Commonly this involves the use of two cylindrical components with a flanged part on each which is larger than the diameter of the towing eye. These parts are secured together through the towing eye by a security lock. Examples of this type of device can be found in GB1526304, GB2245534A and DE4434215.

A common problem with some of these devices is the inability to twist one of the components with respect to the other, without breaking the locking mechanism. This often leads to the device having more external features or more complex locking mechanisms to discourage and resist attack. This in turn often leads to increased manufacturing complexity and therefore cost.

It is the object of this invention to provide an anti-theft device of the two component type to block the towing eye, that is easy to fit, has a small number of parts, is cheap to manufacture and does not rely on the strength of the locking mechanism to secure the two main component parts together, as they are secured using a bolt, and the lock only prevents access to this bolt. The device can easily be manufactured in a range of sizes to suit the different diameters of towing eye. The external flanges are so shaped in order to discourage clamping by gripping tools. When the lock barrel is fitted and the key withdrawn, the barrel is free to turn if an attempt is made to drill it.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings in which:

FIGURE 1 shows a general view of the preferred embodiment when fitted to the towing eye of a drawbar.

FIGURE 2 shows a vertical section on the centreline of the device.

FIGURE 3 shows a general view of the basic upper element of the device, with internal components removed, to show method of fastening to lower element.

FIGURE 4 shows a general view of the basic lower element of the device to show method of fastening to upper element. The invention comprises two elements, one upper 5 and one lower 4, that are bolted together through hole 2 in the towing eye 1 in order to block it. The lower element 4 has a bottom flange which is of larger diameter than the hole in the towing eye 2, and a cylindrical body which is of smaller outer diameter than the diameter of the hole 2 in the towing eye 1. The flange is machined to a domed shape. This lower element 4 is machined from one piece of metal or may be made from two or more components welded or otherwise attached together. The inside diameter of the cylindrical body is machined out for a short distance internally 16, in order to provide a locating seat for a corresponding groove 15 on the upper element 5. A blind hole 11 is drilled centrally in the cylindrical body, and the hole tapped to receive a suitable locking bolt or screw 12. A blind hole 10 is drilled parallel to the tapped hole 11 to receive the dowel pin 9 attached to the upper element 5. The upper element 5 has a flange part of larger diameter than the hole 2 in the towing eye 1, and has a cylindrical body. This upper element is machined from one piece of metal, or may be made from two or more components welded or otherwise attached together. The sides of the flange on the upper element 5 are tapered. The outside diameter of the cylindrical body on the upper element 5 is smaller than the diameter of the hole 2 in the towing eye 1. The end of the cylindrical body is machined 15 to be a close sliding fit with the recess 16 machined in the lower element 4. A dowel pin 9 is attached to the end of the cylindrical body to mate with the corresponding blind hole 10 in the lower element 4. The upper element 5 is drilled and/or machined from the top to various diameters to allow firstly the insertion and seating 8 of the bolt or screw 12 used to secure the two elements together, and secondly the fitment of the removable locking mechanism 6 used to prevent unauthorised access to this bolt or screw 12. An annular recess 7 is machined internally to allow the locking mechanism pin 13 to lock into place. This recess 7 is machined to allow the locking mechanism 6 to spin freely when in the locked position. Another recess 18 is machined internally to allow a rubber or plastic 'O' ring 14 to be fitted. This 'O' ring recess 18 is machined a small distance from the top of the flange.

The device is fitted to the towing eye 1 by first inserting the cylindrical part of the lower element 4 up through the hole 2 in the towing eye 1. The upper element 5 is then inserted from the top. The upper element is turned until the dowel pin 9 mates with the corresponding blind hole 10 in the lower element 4, and the two components are pushed together so that the end of the cylindrical body 15 on the upper element 5 enters the locating diameter 16 in the lower element 4. The securing bolt or screw 12 is then passed through the hole in the top of the upper element 5, through hole 17 in the bottom and screwed into the threaded hole 11 in the lower element 4. The head of the bolt or screw seats in the upper element 5 in a machined recess 8. A standard lock barrel 6 is inserted into the hole 19 in the top of the upper element 5 in the unlocked position, and pushed in until the bottom of the barrel touches the base of the hole. The sides of the barrel are gripped by a plastic or rubber 'O' ring 14, which allows the key 3 in the lock barrel 6 to be turned to the locked position. The locking pin 13 on the lock barrel 6 enters a machined annular recess 7, and the key 3 can be withdrawn. As the 'O' ring 14 does not provide a great amount of grip on the lock barrel 6, and the recess 7 for the locking pin 13 is annular, the lock barrel 6 is free to turn.

Claims

1. An anti-theft device for equipments that are towable using a drawbar with a towing eye, which comprises a lower element being a one piece flanged component that is inserted upwards through the towing eye, and an upper element, also a one pieced flanged component, that is inserted downwards through the towing eye, which mate together by means of a machined recess and groove, and also a single dowel pin and single corresponding hole, and are then fastened together by means of a bolt or screw, the head of which is covered by the insertion of a removable security lock barrel, which once in the locked position with the key removed is free to turn.

2. An anti-theft device as in claim 1 where the one piece upper and one piece lower components are made from two or more components welded or otherwise attached together.

3. An anti-theft device as in claims 1 and 2, where the upper and lower components are mated together using more than one dowel pin and corresponding hole.