GB2357068A

GB2357068A - Anti-theft device for trailers

Info

Publication number: GB2357068A
Application number: GB0029934A
Authority: GB
Inventors: George Alfred Cook
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-12-09
Filing date: 2000-12-08
Publication date: 2001-06-13
Also published as: GB0029934D0

Abstract

An anti-theft device for a trailer unit comprises a sleeve 10 adapted to be locked around the trailer unit king-pin, the sleeve having an external transverse dimension too great to allow said sleeve to be gripped by the fifth wheel coupling of a tractor unit. The sleeve comprises two hinged arcuate sections 10A, 10B which lock together at a point diametrically opposite the hinge 14. An internal annular projection 12 engages into the king-pin recess. A preferred lock is a roller tumbler cam lock 18. The lock may be fitted into a housing 16 integral with one section of the sleeve so that the locking member turns to engage a formation on the other section of the sleeve.

Description

2357068 C1185/C Title: Anti-Theft Device for Trailers

Field of Inventio

This invention relates to an anti-theft device for trailers.

Backeround to the invention Tractor unit/trailer unit mechanical couplings take the form of a so- called "king pin" dependent from the underside of the front of the trailer and a pair of sprung jaws on the back of the tractor unit, commonly known as the "fifth wheel coupling", which engages with and grips the king pin to enable the trailer unit to be towed by the tractor unit. The tractor unit and trailer unit also connect by means of an easily releasable electrical coupling.

The theft of trailer units, which are often loaded with valuable goods, generally occurs when the trailer unit is parked, free of the tractor unit, which for one reason or another has been driven away by the driver. When in this condition, it is possible for another tractor unit to be backed up to the trailer unit to engage the trailer king pin and enable the electrical coupling to be secured, making it possible to drive away the trailer unit complete with its load.

There exist various forms of anti-theft equipment with which the trailer unit can be fitted in an endeavour to prevent thefts of trailers, but such equipment, often of electronic nature, is typically expensive and sometimes not easy to use.

2 Summary of the inventio

According to one aspect of the present invention, there is provided an anti-theft device for a trailer unit which comprises a sleeve adapted to be locked around the trailer unit king pin, the sleeve having an external transverse dimension too great to enable said sleeve to be gripped by the fifth wheel coupling of a tractor unit.

The sleeve preferably comprises two hinged together arcuate sections, each of which may be approximately 180 degrees in extent, which lock together at a point angularly spaced from the hinge, for example diametrically opposite the hinge, to grasp the king pin irremovably except by unlocking.

A kingpin has, intermediate its base plate which bolts to the trailer unit and its free end, an external annular recess with which the fifth wheel coupling engages. The anti-theft sleeve of the present invention therefore preferably has an internal projection, conveniently an annular projection, for engaging into the king pin recess, whereby, when the sleeve is locked to the king pin, axial movement of the sleeve relative to the king pin is substantially prevented.

A preferred lock is a roller tumbler cam lock, conveniently a lock with a locking member which turns with the key. The lock may be designed so that the locking member turns either in a plane parallel to the axis of the lock or in a plane at right angles to the lock axis.

Preferably, the lock is fitted into a lock housing integral with one section of the anti-theft sleeve so that the locking member turns to engage a formation on the other section of the sleeve. If the locking member turns in a plane normal to the lock axis, the said formation may be a pin or the like projecting radially from the said other section of the sleeve. If the locking member turns in a plane parallel to the lock axis, the said formation may be a slot in the said other section of the sleeve.

A preferred anti-theft sleeve is formed by casting and machining from mild steel.

3 Alternatively and preferably the position of the lock is changed to enter the side housing through the wall of one half of the housing instead of through the end of the housing, and instead of the arm engaging a cavity in the wall of the housing, a radial protrusion is provided within the housing with which the arm is aligned after rotation of the key to put the lock into the locked condition, the protrusion being carried by and extending inwardly from the internal wall of the other half of the housing, so that when the two housing halves are pivoted into their closed condition and the key is turned to lock the device, the arm engages behind the protrusion and prevents the two housing halves from being pivoted in the opposite sense, and opened.

According to a further aspect of the present invention each key that is associated with each lock is encoded with a designation that is also provided on the lock to which the key relates or on the main housing or on the side housing containing that lock.

If the lock is not located in the end wall of the side housing, the latter is available to receive the encoding, and represents a convenient place therefor.

A preferred encoding is a coloured patch on the housing and a sin-Alarly coloured key, or keyring, or fob, associated with the key, or coloured patch on part of any of the aforesaid.

According to a yet further aspect of the invention the hinge pin may be received in a blind hole in the lower internal housing part, so that the pin cannot be driven out of the aligned bores in the two housing parts in which the pin is secured, by means of a tool being applied from below. It will be appreciated that no access can be gained from above due to the presence of the plate securing the kingpin to the underside of the trailer.

Preferably the pin and the hole (or both holes) are threaded, so that the pin is held in place by a screw-threaded engagement.

Whether of not a screw thread is employed, preferably the pin is also held in place by means of an adhesive such as Loctite (Trademark).

4 Description of illustrated embodiment

The anti-theft device in accordance with the invention is further described with reference to the accompanying drawings, in which: - Figure 1 shows an anti-theft sleeve in end view; Figure 2 is a cross-section on the line A - A of Figure 1; Figure 3 is a partial side view as seen in the direction of the arrow B in Figure 1; Figure 4 is a partial side view as seen in the direction of the arrow C in Figure 1; and Figure 5 is a fragmentary view looking in the direction of the arrow D in Figure 4.

Figure 6 corresponds to Figure 1 but shows the alternative position for the lock; Figure 7 corresponds to Figure 2 and again shows the alternative position for the lock; Figure 8 is an underside plan view of Figure 6; Figure 9 is a section in AA in Figure 6; Figure 10 is a section in CC in Figure 6, and Figure 11 is a detail of the hinge.

Detailed description of the drawing

Referring to the drawings, the anti-theft device comprises a cylindrical sleeve 10 which internally, intermediate of its ends, has an annular projection 12. The device is preferably formed as by casting and machining from mild steel.

The sleeve is formed as two semi-cylindrical shells IOA, IOB, hinged together at a hinge pin 14.

Diametrically opposite the hinge 14, shell IOA has integrally formed therewith housing 16 for a key operable roller tumbler cam lock 18. Turning the key (not shown) in the cam lock 18 rotates a locking member 20 (see Figure 2) which engages with a pin 22 (see Figures 4 and 5) projecting radially from the other semi-cylindrical shell 10B. This locks the sleeve closed. The key can be withdrawn and the sleeve can only be opened by re-use of the key.

It is alternatively possible to fit the lock tangentially to the sleeve in the housing 16, so that rotation of the key turns the locking member into a slot in the other semi-cylindrical shell 10B in order to lock the sleeve in closed condition.

In use, the anti-theft sleeve can be clamped over the kingpin of a parked trailer unit to prevent theft of the unit. It is not possible to engage the fifth wheel coupling of a tractor unit over the sleeve because its external diameter (89nim) exceeds the maximum distance to which the jaws of the fifth wheel coupling can move apart at their mouth.

The internal diameter (52mm) and axial length (33mm) of the internal annular projection of the sleeve 10 are also important. This annular projection fits into the annular recess of the king pin normally gripped by the fifth wheel coupling, so that in the locked condition, the sleeve has substantially no freedom for movement in the axial direction of the king pin.

The device of the invention is less expensive than known electronic equipment proposed to prevent theft of trailer units, and is much easier to use. Obviously the clamp can be defeated by metal cutting equipment, but it serves as a strong deterrent in the many instances where theft is only possible with swift and quiet action.

In Figs 6-11 of the drawings the lock barrel is denoted by reference numeral 19 and is now located transversely of the side housing 16. The internal protrusion to be engaged by the arm 20 is denoted by 21 (see Fig 9). The hinge pin is denoted by 15 whilst the hinge axis is denoted by 14.

The blocked end of the lower hinge pin hole is denoted by reference numeral 25.

Reference is made to the earlier description of Figs 1 to 5 for a description of the other identified items in Figures 6 to 11.

6 C1185/C

Claims

1. An anti-theft device for a trailer unit which comprises a sleeve adapted to be locked around the trailer unit king-pin, the sleeve having an external transverse dimension too great to enable said sleeve to be gripped by the fifth wheel coupling of a tractor unit.

2. A device as claimed in claim 1 wherein the sleeve comprises two hingedtogether arcuate sections which lock together at a point angularly spaced from the hinge, to grasp the king-pin irremovably except by unlocking.

3. A device as claimed in claim 2 wherein the arcuate sections each extend around 1800 and the locking point is diametrically opposite the hinge.

4. A device as claimed in any of claims 1 to 3 for use with a king-pin having an external annular recess with which the fifth wheel coupling engages, intermediate the plate and the outer free end of the king-pin, and the sleeve has an internal projection for engaging into the king-pin recess, whereby, when the sleeve is locked to the king-pin, axial movement of the sleeve relative to the king-pin is substantially prevented.

5. A device as claimed in claim 4 wherein the internal projection is an annular projection.

6. A device as claimed in any of claims 1 to 5 wherein the lock is a roller tumbler cam lock such as a lock with a locking member which turns with a key.

7. A device as claimed in claim 6 wherein the locking member turns either in a plane parallel to the axis of the lock or in a plane at right angles to the lock axis.

7

8. A device as claimed in any of claims 1 to 7 wherein the lock is fitted into a lock housing integral with one section of the anti-theft sleeve so that the locking member turns to engage a formation on the other section of the sleeve.

9. A device as claimed in claim 8 wherein the locking member turns in a plane normal to the lock axis and the said formation is a pin or the like projecting radially from the said other section of the sleeve.

10. A device as claimed in claim 8 wherein the locking member turns in a plane parallel to the lock axis and the said formation is a slot in the said other section of the sleeve.

11. A device as claimed in any of claims 1 to 10 wherein the sleeve is formed from mild steel.

12. A device as claimed in any of claims 1 to 6 wherein the lock enters the side housing through the wall of one half of the housing instead of through the end of the housing and a radial protrusion is provided within the housing with which an arm is aligned after rotation by the lock key to put the lock into the locked condition, the protrusion being carried by and extending inwardly from the internal wall of the other half of the housing, so that when the two housing halves are pivoted into their closed condition and the key is turned to lock the device, the arm engages behind the protrusion and prevents the two housing halves from being pivoted in the opposite sense, and opened.

13. A device as claimed in claim 12 wherein each key that is associated with each lock is encoded with a designation that is also provided on the lock to which the key relates or on the main housing or on the side housing containing that lock.

14. A device as claimed in any of claims 1 to 13 wherein the hinge pin is received in a blind hole in the lower internal housing part, so that the pin cannot be driven our of aligned bores in the two housing parts in which the pin is secured, by means of a tool being applied from below.

8

15. A device as claimed in claim 14 wherein the pin and the hole (or both holes) are threaded, so that the pin is held in place by a screw-threaded engagement.

16. A device as claimed in claim 14 or 15 wherein the pin is held in place by means of an adhesive.

17. A device as claimed in claim 1, constructed and arranged substantially as herein described by way of example with reference to and as illustrated in the accompanying drawings.