GB2210343A

GB2210343A - Trailer ball hitch coupling security device

Info

Publication number: GB2210343A
Application number: GB8722997A
Authority: GB
Inventors: Graham Stokes
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-09-30
Filing date: 1987-09-30
Publication date: 1989-06-07
Anticipated expiration: 2007-09-30
Also published as: GB2210343B; GB8722997D0

Abstract

The device (17) comprises a housing (18) open at one end (19) to permit insertion therein of the trailer coupling member (11), a protrusion (24) extending upwardly from a lower wall of the housing (18), within the housing, to be received within a recess of the coupling member (11), and, a metal pin (27) carried by the housing (18) and slidable relative thereto between a first position wherein the coupling member can be inserted into the housing (18) and can be positioned with said protrusion (24) of the housing received within said recess of the coupling member (11), and a second position in which the pin (27) lies substantially wholly within the housing (18) and passes above the coupling member (11) to prevent movement of the coupling member (11) relative to the housing (18) in a direction to withdraw said protrusion (24) from said recess, the device further including a locking mechanism (25) which, when operative, effects cooperation between the pin (27) and the housing (18), within the confines of the housing, to prevent withdrawal of the pin (27) from its second position to its first position. <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 for connecting the towable unit to the towing unit.

Towable trailers utilizing the ball hitch principle have a releasable coupling for engaging with a towing ball secured to the rear of the towing vehicle. The coupling member incorporates a socket portion within which the towing ball is received in use. The theft of such towable trailers, in particular caravans, is becomming a serious problem, it being recognised that it is a relatively simple matter for an unauthorised person to hitch the trailer coupling member of a towable trailer to the towing ball of his vehicle so as to facilitate unauthorised towing away of the trailer.

German Gebrauchmuster number 7823082 illustrates a security device produced in an attempt to inhibit such unauthorised towing away of towable trailers. The security device disclosed in Gebrauchmuster 7823082 incorporates a housing within which the coupling member of the trailer is received, the wall of the housing being cut and bent to define upper and lower tongues which cooperate with the socket portion of the coupling member. The shackle of a padlock passes through apertures in the wall of the housing to resist withdrawal of the coupling member from the housing.

While such a security device might deter a casual thief it does not provide a high degree of security since the padlock, including part of the shackle, is readily accessible at the exterior of the housing and so can be relatively simply removed by sawing through the shackle, and moreover since the integral tongues of the housing are formed by bending part of the housing wall their root portions are readily accessible at the exterior of the housing and can be removed by sawing or chiseling.

We have previously proposed a security device which does not suffer from the disadvantages outlined above, and which makes use of a transverse metal pin which is wholly received within the housing, and lies behind a protruding operating handle of the coupling member when the coupling member is received in the housing. While our prior proposal is suitable for use with a wide variety of coupling members, there are certain coupling members whose design renders it impractical to position a retaining pin of the housing behind a protruding operating lever of the coupling member, and it is an object of the present invention to provide a security device which can be used in conjunction with a wide variety of coupling members, and in particular those where it is impractical to position the retaining pin behind the protruding release lever of the coupling member.

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 of the trailer coupling member, a protrusion extending upwardly from a lower wall of the housing, within the housing, to be received within a recess of the coupling member, and, a metal pin carried by the housing and slidable relative thereto between a first position where inn the coupling member can be inserted into the housing and can be positioned with said protrusion of the housing received within said recess of the coupling member, and a second position in which the pin lies substantially wholly within the housing and passes above the coupling member to prevent movement of the coupling member relative to the housing in a direction to withdraw said protrusion from said recess, the device further including a locking mechanism which, when operative, effects cooperation between the pin and the housing, within the confines of the housing, to prevent withdrawal of the pin from its second position to its first position.

Preferably said pin is freely rotatable about its longitudinal axis in said housing and said locking mechanism, when operative to prevent said withdrawal movement of the pin, permits such rotation.

One example of the invention is illustrated in the accompanying drawings wherein, Figure 1 is a perspective view of a trailer coupling member and a security device for use in conjunction therewith, and Figure 2 is a diagrammatic sectional view of the security device applied to the coupling member.

Referring to the drawings, the coupling member 11 is illustrated attached to a trailer draw bar 12 by means of bolts 13. The nature of the coupling member 11 is not of great significance to the present invention, and the coupling 11 illustrated in the drawings is of a relatively complex construction embodying a lever operated arrangement 14 whereby a pair of oppositely directed plungers may be caused to grip the towing ball received in the recess 15 of the coupling member in use. The coupling member 11 includes a manually operable release lever 16 which projects upwardly and rearwardly from the top face of the coupling member 11.

The security device 17 comprises a generally rectangular housing 18 formed from a length of rectangular section steel tube, open at one end 19 to permit insertion of the coupling and closed at the opposite end 20. The top wall 21 of the housing 18 is formed with a slot 22 extending lengthwise of the housing from the open end 19 for receiving the release lever 16 of the coupling member 11. The arrangement is such that the coupling member 11 is introduced sufficiently far into the housing 18 that the bolts 13 lie within the confines of the housing.

A known method of overcoming security devices is simply to unbolt the coupling from the draw bar of the trailer so that the coupling together with the security device can be removed and a subsitute coupling member can then be fitted to the draw bar to permit the unauthorised removal of the trailer. In the arrangement illustrated in the drawings the bolts securing the coupling member 11 to the draw bar 12 are within the confines of the housing and thus unbolting the draw bar would be difficult if not impossible. In the arrangement illustrated the horizontally extending bolt 13 passes through a region of the coupling member 11 which is of reduced width by comparison with the remainder of the coupling member.Since the internal width of the housing 18 is governed by the maximum width of the coupling member then there is a significant clearance between the bolt and the inner surfaces of the side walls of the housing. In order to further restrict the access to this bolt the side walls of the housing 18 are provided internally with inwardly projecting abutments 23 which, when the coupling member 11 is fully inserted into the housing 18, align with the horizontal bolt 13 and prevent removal of the bolt 13 even if the nut securing the bolt 13 in position can be loosened. Both abutments 23 are counterboard to permit the fitting thereto of one or more extension pieces so that the same housing can be used withnarrower coupling members.The abutments 23 do not impede introduction of the coupling member into the housing since the widest portions of the coupling member (in this case the lever mechanism 14) can pass above the abutments 23.

Disposed on the centre line of the lower wall of the housing 18, and positioned adjacent the closed end 20 of the housing is an upstanding cylindrical post 24. The post 24 can be provided in a number of ways, but is conveniently defined by a short length of cylindrical steel bar having one of its axial end faces welded to the upper surface of the lower wall of the housing 18.

When the coupling member 11 is correctly inserted in the housing 18 the housing is moved relative to the coupling so that the post 24 seats within the recess 15 of the coupling. In effect therefore during insertion of the coupling member it must be lifted relative to the lower wall of the housing and then lowered over the post 24.

One side wall of the housing 18, adjacent the closed end 20, includes a lock chamber 25. The lock chamber 25 can be intergral with the side wall of the housing, but preferable is provided by a steel pressing welded to the outer surface of the side wall. Aligned with the lock chamber 25 the two opposite side walls of the housing 18 are formed with circular apertures 26 through which a cylindrical hardened steel pin 27 can be introduced. A cylindrical flange 28 encircles the aperture 26 remote from the lock chamber 25 to provide a sliding bearing for the pin 27. The flange 28 is conveniently provided by a short length of cylindrical steel tubing welded to the side wall of the housing.

Fixed within the lock chamber 25 is a key operated lock mechanism, the removable key 29 of which is seen in Figure 1. Adjacent one axial end the pin 27 is formed with a peripheral groove 31 and when the pin 27 is fully inserted in the housing 18 the end region containing the groove 31 lies within the lock chamber 25. The locking mechanism operated by the key 29 includes a locking element which can enter the groove 31 to prevent withdrawal of the pin 27. The locking element does not prevent rotation of the pin relative to the housing, and in order to withdraw the element from the groove 31 it is necessary to operate the lock mechanism by means of the appropriate key 29. the positioning of the lock chamber 25 and the apertures 26 is such that the pin 27 passes over that region of the coupling member 11 formed with the recess 15.The clearance between the pin 27 and the upper surface of the coupling member 11 is sufficiently small to ensure that with the pin 27 in place the coupling member 11 cannot be lifted sufficiently far relative to the lower wall of the housing 11 to disengage the post 24 from the recess 15. Thus withdrawal of the coupling member from the housing, when the pin 27 is in position, is prevented.

When the pin 27 is fully inserted into the housing the end of the pin remote from the groove 31 lies flush with the end of the flange 28, and thus the pin is wholly masked by the housing and is not accessible and thus cannot be sawn through. Even in the event that a saw blade is introduced into the housing from the open end 19 then the pin will rotate relative to the housing during any sawing action thus frustrating the sawing action. If desired a retaining chain 32 can be provided to link the pin 27 to the housing 18 thus removing the risk of losing the pin 27 after it has been withdrawn. Moreover, the chain 32 faciliates withdrawal of the pin 27 after release of the locking mechanism by means of the key 29.

It will be noted that the side walls of the housing, adjacent the open end 19, are provided with slots or recesses 33 to accommodate projecting portions of the lever mechanism 14. Such recesses 33 are needed only for the particular type of coupling member illustrated in Figure 1, but can, if desired, be provided in all versions of the security device 17 irrespective of the nature of the coupling member 11 so that the construction of the housing 18 can be standarised.

Desirably the width of the slot 22 is only fractionally greater than the thickness of the lever 16 thereby further restricting unauthorised access to the interior of the housing in use.

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 of the trailer coupling member, a -protrusion extending upwardly from a lower wall of the housing, within the housing, to be received within a recess of the coupling member, and, 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 can be positioned with said protrusion of the housing received within said recess of the coupling member, and a second position in which the pin lies substantially wholly within the housin-g and passes above the coupling member to prevent movement of the coupling member relative to the housing in a direction to withdraw said protrusion from said recess, the device further including a locking mechanism which, when operative, effects cooperation between the pin and the housing, within the confines of the housing, to prevent withdrawal of the pin from its second position to its first position.

2. A security device as claimed in claim 1 wherein said pin is freely rotatable about its longitudinal axis in said housing and said locking mechanism, when operative to prevent said withdrawal movement of the pin, permits such rotation.

3. A security device as claimed in claim 1 or claim 2 wherein the housing is slotted to accomodate a protruding lever of coupling member, the slot being just wide enough to receive the lever.

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