GB2255538A

GB2255538A - Security device

Info

Publication number: GB2255538A
Application number: GB9110214A
Authority: GB
Inventors: Graham Stokes; Carolyn Ann Stokes
Original assignee: GRAYSPEED LEISURE PRODUCTS LIM
Current assignee: GRAYSPEED LEISURE PRODUCTS LIM
Priority date: 1991-05-10
Filing date: 1991-05-10
Publication date: 1992-11-11
Anticipated expiration: 2011-05-10
Also published as: GB2255538B; GB9110214D0

Abstract

An anti-theft security device (11) for use in conjunction with a ball hitch coupling member (13) of a trailer, comprises a housing (15) open at one end to permit insertion of the coupling member longitudinally into the housing (15), a pin (24) carried by the housing (15) and slidable between a position in which the coupling member can be inserted into the housing (15) and a position in which the pin (24) passes behind a release lever (14) of the coupling member preventing withdrawal of the coupling member from the housing (15), a slot (18) and a re-entrant slot (31) extending from the open end of the housing (15) on opposite walls thereof permitting the coupling member to extend through the housing (15) transverse to its length, the pin (24) being arranged to be inserted behind the release lever (14) to prevent withdrawal of the coupling member from the housing (15) and a locking mechanism (19) to prevent withdrawal of the pin (24). The device can be used when the trailer is coupled or uncoupled. <IMAGE>

Description

SECURITY DEVICE This invention relates to a security device for use with caravans and other towable trailers of the kind utilizing a ball hitch.

Towable trailers utilizing ball hitches have a releasable coupling member for engagement with a towing ball secured to the rear of the towing vehicle. The coupling member incorporates a manually operable release lever which projects, in use, upwardly from the coupling member.

Release of the coupling from the associated towing ball is very simple, entailing moving the release lever through its full range of movement and while holding the lever at the end of its range of movement, lifting the coupling away from the ball. It will be understood therefore that not only are trailers susceptible to theft when disconnected from their towing vehicle, but also, by virtue of the simplicity with which the coupling can be released, there is a danger of theft when the trailer and towing vehicle are coupled together, but are at rest, for example in a motorway car park.

Our British Patent No 2193938 discloses a security device which can be applied to the coupling of a trailer when the trailer is disconnected from its towing vehicle, the security device preventing the coupling being attached to a towing ball, and thus preventing unauthorised towing of the trailer. It is an object of the present invention to provide a security device which can perform the same function as that performed by the device disclosed in our British Patent 2193938, and which can also be used to prevent authorised disconnection of a coupling from its mated towing ball, and so can be used to minimise the risk of theft of the trailer by unauthorised disconnection of the trailer from its towing vehicle.

In accordance with the present invention there is provided a security device for use in conjunction with a ball hitch coupling member of a trailer, the device comprising a housing open at one end to permit insertion therein, longitudinally of the housing, of the trailer coupling member, a metal pin carried by the housing and slidable relative thereto between a first position wherein the coupling member can be inserted into the housing and a second position in which the pin lies wholly within the housing and passes behind the protruding release lever of the coupling member to prevent withdrawal of the member from the housing, a slot extending in one wall of the housing, from said one end of the housing, and, a re-entrant slot extending from said one end of the housing in the wall of the housing opposite said one wall, said slot and said re-entrant slot permitting said coupling member to extend through the housing transverse to the length of the housing to an abutment position wherein said pin can be introduced behind said release lever to prevent withdrawal of the coupling member from the housing in said direction transverse to the length of the housing, there being a locking mechanism which r when operative, effects co- operation between the pin and the housing to prevent withdrawal of the pin from its second position.

One example of the invention is illustrated in the accompanying drawings wherein: Figure 1 is a perspective view of a security device, Figure 2 is a view similar to Figure 1 showing the device in use in conjunction with a ball hitch coupling member disengaged from its associated towing ball, and Figure 3 is a perspective view illustrating the security device of Figure 1 in use in conjunction with a ball hitch coupling member engaged with a mating towing ball.

Referring to the drawings the security device 11 is intended for use with the coupling member 12 of a towable trailer. A wide variety of different coupling members are known, but all work on the same general principle in that they consist of a metal pressing or casting 13 of channel-shaped cross-section which is bolted to the drawbar 12a of the towable trailer and which is shaped at its free end to receive the towing ball of the towing vehicle. Each coupling member includes an L-shaped pivotable, manually operable release lever 14 which protrudes upwardly from, and then parallel to, the pressed or cast housing 13 of the coupling member, and which is coupled within the housing to a catch mechanism for retaining the towing ball within the coupling housing in use. The towing ball is carried at one end of a curved rigid bar 20 rigidly secured to the rear of the towing vehicle.The pivoted lever 13 is spring urged to a position in which one of its limbs is at right angles to the length of the housing 13, and the other of its limbs is parallel to the housing 13. In order to release a towing ball mated with the free end of the housing 13 it is necessary to pivot the lever 14 to move the parallel limb upwardly away from the housing 13 through approximately 750 so as to release the catch mechanism and permit the coupling member to be lifted away from the towing ball.

The security device 11 includes a hollow, elongate, metal housing 15 of rectangular cross-section; conveniently externally case hardened; closed at one end 16 and open at its opposite end 17 to permit introduction therein of the coupling member 12. As is apparent from Figure 2, the coupling member is inserted into the housing, longitudinally of the housing after disconnection from an associated towing ball, and it will be understood therefore that in this mode of operation the security device 11 is intended to protect against theft of the trailer by preventing unauthorised engagement of the coupling member with a towing ball. The wall 15a of the housing 15 which is uppermost in use is formed with an elongate, closed ended slot 18 extending longitudinally from the open end 17 of the housing and shaped to accommodate the protruding release lever of the coupling member 12 as a close fit.However, adjacent the open end 17 of the housing the slot 18 is formed with a region 18a which tapers in width from the width of the housing 15 to the width of the major portion of the slot 18.

On one side wall the housing 15 includes a lateral extension defining a lock compartment 19. The lock compartment 19 is rectangular in transverse cross-section and extends parallel to the length of the housing 15.

The opposite side walls of the housing 15 are formed with respective, aligned, circular apertures 21, 22, the wall of the aperture 21 being extended to define a bush 23, and the aperture 22 opening into the lock compartment 19.

A hardened steel, cylindrical, pin 24 having a circumferential groove 25 adjacent one axial end thereof is slidable transversely in the housing by way of the apertures 21, 22, the diameter of the pin 24 being slightly less than the diameter of the apertures. A chain 26 or other restraining device, for example a metal cable, is secured at one end to the end of the pin 24 remote from the groove 25, and is secured at its other end to the wall of the housing 15.

A lock mechanism is secured within the compartment 19 the key-receiving barrel of the lock mechanism being accessible through an aperture in the outer wall of the compartment 19. Within the compartment 19 the lock mechanism includes a locking arrangement engageable within the groove 25 of the pin 24 so that after the pin has been inserted through the apertures 21 and 22 to a position in which the groove 25 is within the compartment 19, and the opposite end of the pin lies within the bush 23, the locking mechanism can be operated to lock the pin 24 against withdrawal. The groove 25 is a circumferential groove, and thus while the pin 24 is locked against withdrawal it is still free to rotate about its longitudinal axis.The locking mechanism can of course take a number of different forms but a convenient locking mechanism has a hardened steel peg which, in the locked position of the mechanism, lies within the groove 25 of the pin 24. In the unlocked position of the locking mechanism the peg is moved out of the groove 25 to permit withdrawal of the pin 24 from the housing.

The first mode of operation of the security device is as follows. The locking mechanism is released to permit withdrawal of the pin 24 and the pin is withdrawn. With the wall 15a of the housing uppermost the open end 17 of the housing is offered to the trailer coupling member, from which the associated towing ball has been disconnected so detaching the trailer from the towing vehicle. The housing is then moved longitudinally over the coupling so that the coupling member is received within the housing 15 and the upstanding limb of the release lever 14 projects upwardly through the slot 18.

The longitudinal extent of the housing 15 is such that the whole of the coupling member 12 is received within the housing, including the region of the coupling member which is bolted to the draw bar 12a of the trailer. In this way the securing bolts for securing the coupling member to the draw bar are within the housing. When the coupling member 12 is fully within the housing 15 the front edge of the upstanding limb of the release lever 14 is closely adjacent the closed end of the slot 18 and the front end of the coupling member 12 lies beneath an internal flange 27 in the housing. The lower face of the coupling member 12 is resting on, or closely adjacent the lower face 15b of the housing.

Next the pin 24 is introduced, with its grooved end first, through the aperture 21 and is slid laterally with respect to the housing to engage also in the aperture 22.

In this position the pin 24 extends behind the upstanding limb of the lever 14 of the coupling member and beneath the parallel limb of the lever. The locking mechanism is then operated to lock the pin 24 against withdrawal, and it will be recognised that co-operation of the pin with the rear edge of the upstanding limb of the lever 14 prevents withdrawal of the coupling member from the housing. The close-fit of the slot 18 about the lever 14, and the rotatability of the hardened steel pin 24 frustrate attempts to remove the security device 11 from the coupling member 12 by sawing through the pin 24, and the enclosure of the region of the coupling member 12 connected by bolts to the draw bar of the trailer resists unbolting of the coupling member from the draw bar.

The security device described above is extremely effective in preventing theft of trailers which have been detached from their towing vehicle. However, there is a growing trend of theft of trailers in situations where the trailer is parked connected to its towing vehicle as can occur for example on a motorway car park. The owner of the trailer may leave the towing vehicle and trailer coupled together by the ball hitch coupling and may leave the combination for only a few moments. A thief equipped with a towing vehicle having a ball hitch will disconnect the trailer from the towing vehicle and couple the trailer to his own towing vehicle and drive away. It will be recognised that this takes only a few moments.

It is known to provide a locking mechanism within the release lever construction, to resist unauthorised movement of the release lever of the coupling member to its release position. However, such locking mechanisms are notoriously insecure, and easily defeated and prove to be little or no deterrent to the determined thief.

As is apparent from Figures 1, 2 and 3 the lower wall 15b of the housing 15 has, extending longitudinally from the open end 17 of the housing, a slot 31 the shape of which corresponds to the cross-sectional shape of the housing of the coupling member 12. Associated with the open end of the slot 31 are a pair of oppositely directed L-shaped members 32 formed from hardened steel rod, each having one limb welded to the wall 15b, and the other limb extending towards the centre line of the wall 15b. The spacing between the free ends of the inwardly directed limbs of the members 32 is less than the width of the slot 31, and thus in conjunction with the slot 31 the members 32 define a re-entrant aperture in the wall 15b.

Figure 3 shows the alternative mode of operation of the security device 11. While the coupling member 12 is still engaged with the towing ball of the towing vehicle the security device is offered to the coupling member 12 with the housing 15 vertically orientated and its open end 17 lowermost. The lower wall 15b of the housing is presented to the towing vehicle and the housing 15 is lowered over the front end of the housing 13 of the coupling member 12 so that the members 32 and the slot 31 pass between the front end of the coupling member 12 and the towing vehicle, the enlarged portion 18a of the slot 18 in the upper wall 15a of the housing accommodating the housing 13 of the coupling member during this movement, and the release lever 14 being accommodated within the remainder of the slot 18.When the inturned limbs of the members 32 pass beneath the lower edge of the housing 13 the security device 11 is moved lengthwise of the coupling member 12 so that the inturned portions of the members 32 slide beneath the housing 13 and the housing 13 projects through the slot 31 in the wall 15b of the housing 15. The security device is moved lengthwise of the coupling member housing until the upstanding part of the release lever 14 abuts the inner surface of the lower wall 15b of the housing whereupon no further movement is possible. With the housing 15 and the coupling member 12 so positioned the pin 24 can be slid through the apertures 21 and 22 passing to the rear of the upstanding part of the release lever and below the longitudinally extending part of the release lever.It will be recognised therefore that when locked in position the pin 24 prevents movement of the security device housing 15 longitudinally of the coupling member towards the towing vehicle, and abutment of the release lever with the inner surface of the lower wall of the housing 15 prevents movement of the security device in the opposite direction. The inturned portions of the members 32, lying beneath the housing 13 of the coupling member 12 prevent upward movement of the security device relative to the coupling member and it will be recognised therefore that the housing 15 is locked to the coupling member 12 and prevents movement of the release lever 14 to release the coupling member 12 from its associated towing ball. The lever 14 can be pivoted through a small distance relative to its housing 13 as permitted by the length of the slot 18, and as permitted by pivoting movement of the security device relative to the housing 13 of the coupling member. However, the freedom of movement of the housing 15 relative to the coupling member 12 is much too small to permit movement of the lever 14 to the release position.

It will be understood therefore that in addition to use to prevent unauthorised use of an uncoupled trailer the security device 15 can be used in an alternative mode (turned through 900) to prevent release of a coupling member 12 from an associated towing ball. Thus the security device can be used to prevent theft when the trailer is coupled to its towing vehicle, and when the trailer has been disconnected from its towing vehicle.

It is to be understood that it is undesirable for the security device to be in place while the trailer is being towed since should an accident occur in which rapid disconnection of the towing vehicle from the trailer is required, then the presence of the security device would seriously hinder such rapid disconnection.

It is to be understood that references herein to "trailer" include all forms of trailer, caravan, and the like which may be towed behind a towing vehicle through the intermediary of a ball hitch coupling.

In a modification the circular section rod used to form the members 32 is replaced by rectangular section bar, and in a still further modification the members 32 are defined by integral extensions of the lower wall 15b of the housing 15.

In an alternative construction the members 32 are dispensed with completely, and the housing 13 of the coupling member 12 carries an upstanding bracket having a circular aperture therein dimensioned to receive the pin 24. The bracket is so positioned on the housing 13 of the coupling member that the aperture of the bracket is disposed in the corner defined by the L-shaped release lever 14 and in both modes of operation of the security device the pin 24 passes through the aperture 21 of the housing 15, the aperture of the bracket secured to the housing 13, and the aperture 22 of the housing 15. Thus the pin 24 and the bracket secured to the coupling member provide a physical interconnection between the housing 15 and the coupling member in both modes of operation. It will be recognised that in the second mode the members 32 are not required since all directions of movement of the housing 15 relative to the coupling member 12 are prevented by the engagement of the pin 24 in the aperture of the bracket secured to the coupling member. Moreover, if desired, both in the alternative described above and in the construction described with reference to Figures 1 to 3, the housing can be so dimensioned that in the first mode of operation the whole of the coupling member including the release lever 14 can be received within the housing, the slot 18 being dimensioned to accommodate the member and its lever 14 in the second mode of operation.

Claims

1. A security device for use in conjunction with a ball hitch coupling member of a trailer, the device comprising a housing open at one end to permit insertion therein, longitudinally of the housing, of the trailer coupling member, a metal pin carried by the housing and slidable relative thereto between a first position wherein the coupling member can be inserted into the housing and a second position in which the pin lies wholly within the housing and passes behind the protruding release lever of the coupling member to prevent withdrawal of the member from the housing, a slot extending in one wall of the housing, from said one end of the housing, and, a re-entrant slot extending from said one end of the housing in the wall of the housing opposite said one wall, said slot and said re-entrant slot permitting said coupling member to extend through the housing transverse to the length of the housing to an abutment position wherein said pin can be introduced behind said release lever to prevent withdrawal of the coupling member from the housing in said direction transverse to the length of the housing, there being a locking mechanism which, when operative, effects cooperation between the pin and the housing to prevent withdrawal of the pin from its second position.

2. A security device as claimed in Claim 1 in which the housing is of rectangular cross section.

3. A security device as claimed in Claim 1 or Claim 2 in which the housing is constructed from a metal.

4. A security device as claimed in any one of the preceding claims in which the slot is shaped so as to accommodate the release lever of the coupling member.

5. A security device as claimed in Claim 4 in which the width of the slot is tapered adjacent the open end of the housing from the width of the housing to the width of the major portion of the slot.

6. A security device as claimed in any one of the preceding claims in which the side walls of the housing are provided with aligned apertures, the pin being slidable by way of the apertures between its first and second positions.

7. A security device as claimed in any one of the preceding claims in which the locking mechanism comprises a key operated lock engageable with a groove formed in the pin.

8. A security device as claimed in any one of the preceding claims in which the re-entrant slot comprises a second slot and a pair of oppositely directed L-shaped members each having one limb attached to the housing adjacent the entrance to the second slot, the other limb of each member extending inwardly.

9. A security device as claimed in Claim 8 in which the L-shaped members are formed from hardened steel rod.

10. A security device for use in conjunction with a ball hitch coupling member of a trailer, the coupling member carrying an upstanding bracket having an aperture formed therein, the security device comprising a housing open at one end to permit insertion therein, longitudinally of the housing, of the trailer coupling member, a metal pin carried by the housing and slidable relative thereto between a first position wherein the coupling member can be inserted into the housing and a second position in which the pin lies wholly within the housing and extends through the aperture provided in the upstanding bracket of the coupling member, to prevent withdrawal of the coupling member from the housing, a first slot extending in one wall of the housing from said one end of the housing, and a second slot extending from said one end of the housing in the wall of the housing opposite said one wall, said first and second slots permitting said coupling member to extend through the housing transverse to the length of the housing to a position wherein said pin can be introduced through the aperture provided in the upstanding bracket of the coupling member, to prevent withdrawal of the coupling member from the housing, there being a locking mechanism which, when operative, effects cooperation between the pin and the housing to prevent withdrawal of the pin from its second position.

11. In combination, a security device as claimed in Claim 10 and a ball hitch coupling member carrying an upstanding bracket having an aperture formed therein for receiving the pin of the security device.

12. A security device substantially as hereinbefore described with reference to the accompanying drawings.