GB1572792A

GB1572792A - Anti-theft device

Info

Publication number: GB1572792A
Application number: GB4258575A
Authority: GB
Original assignee: Powell & Jones Ltd
Current assignee: Powell & Jones Ltd
Priority date: 1977-01-17
Filing date: 1977-01-17
Publication date: 1980-08-06

Description

(54) ANTI-THEFT DEVICE (71) We, POWELL AND JONES LIMITED, of Rigby Street, Wednesbury, West Midlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to an anti-theft device for parked trailers that are provided with grooved king pins by which they are arranged to be coupled to a tractor unit.

A trailer is generally coupled to a tractor unit by a releasable coupling comprising a grooved king pin on the trailer and a corresponding socket connector on the tractor. The coupling used is always basically the same in order to allow trailers and tractor units to be interchangeably coupled together, thereby allowing the tractor units to be used more efficiently. However, this feature does result in one disadvantage in that it facilitates unauthorised removal of parked trailers, this being a particularly serious disadvantage when using trailers to carry valuable loads.

This disadvantage is reduced or overcome according to the present invention by providing an anti-theft device comprising a body portion formed with a first recess to receive a grooved end portion of a king pin and a second recess in which a key-operated locking mechanism is secured, the locking mechanism controlling operating of a lock member within the body portion so that setting of the locking mechanism to a locked condition sets the lock member to a locked position in which it projects laterally into said first recess, the lock member being arranged in its locked position to engage in the groove of a king pin in the first recess to lock the body portion to the king pin.

Preferably, the first and second recesses are cylindrical recesses opening out of the body portion in opposite directions with their axes parallel but radially offset relative to one another, and the lock member comprises an eccentric portion and is mounted so as to rotate, about an axis parallel to the axes of both recesses, in a chamber communicating laterally with the first recess to that rotation of the lock member to its locked position causes the eccentric portion to proJect into the first recess.

One embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: - Figure 1 is a plan view of an anti-theft device according to the invention, and Figure 2 is a section along the line 2-2 in Figure 1.

The illustrated device has a body portion in the form of a malleable cast iron body 1 comprising a socket portion 2 formed with a cylindrical recess 3 to receive the king pin of a trailer as a close fit (as shown in broken lines in Figure 2), and a lock-housing portion 4 which projects laterally from the socket portion 2 and is formed with a cylindrical recess 5 with its central axis parallel to, and radially offset from that of recess 3 and opening out of the body portion in the opposite direction to that of recess 3. The inner end of recess 5 opens into a chamber 6 which in turn opens laterally into the recess 3.

A key-operated cylinder locking mechanism 7 is secured in the open end of recess 5 and has a locking spindle 8 which projects rearwards parallel to the axis of the recess and is connected co-axially to one end of a pin 9 of a lock member comprising an eccentric 10 mounted on the pin 9 in the chamber 6. The other end of the pin 9 is pivotally mounted in a blind bore in the body 1 so that, in setting the locking mechanism to a locked condition, the locking spindle 8 and pin 9 rotate together under control of the locking mechanism 7 and turn the eccentric 10 between an unlocked position in which it is located fully within the chamber 6 (as shown in full lines in Figure 2), and a locked position in which it projects laterally into the recess 3 and into the annular groove of a king pin in recess 3 (as shown in broken lines in Figures 1 and 2). The eccentric 10 has a circular profile with a radius slightly less than that of the recess 5 so that it can be inserted therethrough into the chamber 6, but because the eccentric is mounted eccentrically on the pin 9, with the pin axis radially offset from the axis of recess 5 towards the recess 3, it projects into the recess 3 as it rotates with the pin to the locked position. When the lock member is in its unlocked position, the eccentric is arranged coaxially with the recess 5.

The housing 11 of the locking mechanism 7 is a close fit in the recess 5 and is secured therein by adhesive, for example, that sold under the trade name "Loctite" (registered Trade Mark) and by a peg 12 which is inserted laterally of the locking mechanism through aligned holes bored in the body 1 and housing 11. The peg 12 might, in an alternative embodiment of the invention extend the full length of the holes in the body and the housing, but preferably, it is shorter so that it engages the hole in the housing 11 and projects along only part of the length of the hole in the body. A hardened steel ball 13 is then inserted into the hole in the body and the hole is closed by a second short peg 14.

Both pegs are a tight fit in the holes, and the head of the second peg 14 may be enlarged as originally formed so as to be deformed when inserted into the hole. Also, an adhesive is used to help secure the pegs and the ball in place. The purpose of the ball is to protect the peg 12 against being drilled-out in an attempt to remove the locking mechanism so that the locked device can be forcibly removed from a king pin. The hardness of the ball and its curved surface serve to deflect the drill bit away from the peg 12 should it penetrate the second peg 14.

The locking spindle 8 is connected to the end of pin 9 by a threaded connection 15 which is additionally secured by adhesive.

This connection makes it even more difficult to forcibly remove the locking mechanism when it is locked, the eccentric 10 then projecting into the recess 3 so that it cannot be withdrawn axially from its chamber 6.

The eccentric 10 is secured to the pin 9 by a transverse peg 16 which is inserted through aligned holes in the pin and the eccentric, as shown in Figure 1.

It will be appreciated that the illustrated anti-theft device is relatively simple in construction and affords the least opportunities for tampering. The strength of the body resists shattering and the eccentric is inaccessible and can only be operated through the cylinder locking mechanism.

WHAT WE CLAIM IS: 1. An anti-theft device for parked trailers that are provided with grooved king pins by which they are arranged to be coupled to a tractor unit, the device comprising a body portion formed with a first recess to receive a grooved end portion of a king pin and a second recess in which a keyoperated locking mechanism is secured, the locking mechanism controlling operation of a lock member within the body portion so that setting of the locking mechanism to a locked condition sets the lock member to a locked position in which it projects laterally into said first recess, the lock member being arranged in its locked position to engage in the groove of a king pin in the first recess to lock the body portion to the king pin.

2. A device as claimed in Claim 1 in which the lock member comprises an eccentric portion and is rotatable in a chamber within the body portion between said locked position and an unlocked position under control of the locking mechanism, said chamber communicating laterally with said first recess so that the eccentric portion projects into said first recess in the locked position of the lock member but lies entirely within the said chamber in the unlocked position.

3. A device as claimed in Claim 1 or 2 in which the first and second recesses have parallel, radially offset, central axes and open out of the body portion in opposite directions, the locking mechanism being a key-operated cylinder locking mechanism which is secured in said recess and comprises a projecting rotatable locking spindle which engages the lock member for movement of the lock member.

4. A device as claimed in Claim 3 as dependent on Claim 2 in which said recess is cylindrical and the eccentric portion of the lock member has a circular profile with a radius slightly less than that of said second recess so that it can be inserted therethrough into said chamber during assembly.

5. A device as claimed in Claim 4 in which the axis of rotation of the lock member is radially offset from the central axis of said second recess, towards said first recess, and the eccentric portion is arranged co-axiall with said second recess when the lock member is in its unlocked position.

6. A device as claimed in any one of Claims 3, as dependent on Claim 2,4 or 5 in which the eccentric portion of the lock member is secured to a pin, one end of which is co-axially engaged with said locking spindle and the other end of which is rotatably engaged in a blind bore in the body portion.

7. A device as claimed in Claim 6 in which the pin and locking spindle are connected by a threaded connection.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. is located fully within the chamber 6 (as shown in full lines in Figure 2), and a locked position in which it projects laterally into the recess 3 and into the annular groove of a king pin in recess 3 (as shown in broken lines in Figures 1 and 2). The eccentric 10 has a circular profile with a radius slightly less than that of the recess 5 so that it can be inserted therethrough into the chamber 6, but because the eccentric is mounted eccentrically on the pin 9, with the pin axis radially offset from the axis of recess 5 towards the recess 3, it projects into the recess 3 as it rotates with the pin to the locked position. When the lock member is in its unlocked position, the eccentric is arranged coaxially with the recess 5. The housing 11 of the locking mechanism 7 is a close fit in the recess 5 and is secured therein by adhesive, for example, that sold under the trade name "Loctite" (registered Trade Mark) and by a peg 12 which is inserted laterally of the locking mechanism through aligned holes bored in the body 1 and housing 11. The peg 12 might, in an alternative embodiment of the invention extend the full length of the holes in the body and the housing, but preferably, it is shorter so that it engages the hole in the housing 11 and projects along only part of the length of the hole in the body. A hardened steel ball 13 is then inserted into the hole in the body and the hole is closed by a second short peg 14. Both pegs are a tight fit in the holes, and the head of the second peg 14 may be enlarged as originally formed so as to be deformed when inserted into the hole. Also, an adhesive is used to help secure the pegs and the ball in place. The purpose of the ball is to protect the peg 12 against being drilled-out in an attempt to remove the locking mechanism so that the locked device can be forcibly removed from a king pin. The hardness of the ball and its curved surface serve to deflect the drill bit away from the peg 12 should it penetrate the second peg 14. The locking spindle 8 is connected to the end of pin 9 by a threaded connection 15 which is additionally secured by adhesive. This connection makes it even more difficult to forcibly remove the locking mechanism when it is locked, the eccentric 10 then projecting into the recess 3 so that it cannot be withdrawn axially from its chamber 6. The eccentric 10 is secured to the pin 9 by a transverse peg 16 which is inserted through aligned holes in the pin and the eccentric, as shown in Figure 1. It will be appreciated that the illustrated anti-theft device is relatively simple in construction and affords the least opportunities for tampering. The strength of the body resists shattering and the eccentric is inaccessible and can only be operated through the cylinder locking mechanism. WHAT WE CLAIM IS:

1. An anti-theft device for parked trailers that are provided with grooved king pins by which they are arranged to be coupled to a tractor unit, the device comprising a body portion formed with a first recess to receive a grooved end portion of a king pin and a second recess in which a keyoperated locking mechanism is secured, the locking mechanism controlling operation of a lock member within the body portion so that setting of the locking mechanism to a locked condition sets the lock member to a locked position in which it projects laterally into said first recess, the lock member being arranged in its locked position to engage in the groove of a king pin in the first recess to lock the body portion to the king pin.

8. A device as claimed in any one of the

preceding claims in which the locking mechanism is secured in said second recess by a peg which extends laterally of the locking mechanism through aligned holes in the body portion and a housing of the locking mechanism.

9. A device as claimed in Claim 8 in which said peg is of such a length as to leave a portion of said hole in the body portion unoccupied, there being a hardened metal ball inserted into said unoccupied portion of the hole and a second peg inserted therein after said ball.

10. An anti-theft device substantially as herein described with reference to the accompanying drawings.