GB2248430A - Anti theft device for towing hitch - Google Patents

Abstract

The device 33 comprises a partially spherical body 34 arranged to locate in a hemispherical recess 16 on the underside of a hook receiver 14. The device 33 is locked in place by engagement of a threaded bar 38, carried by the device 33, in a threaded hole 36 provided in the recess 16. The bar 38 is engaged by rotation of an attached rod 40 connected to a lock mechanism 42 so that rotation of the rod requires the insertion of a key (not shown) into the lock 42. The body 34 is prevented from rotating with the rod 40 by engagement of a pin 44 in a corresponding hole 46 in the hook receiver 14. In this way the device 33 prevents the hook receiver 14 from being connected to a hook for movement of the attached vehicle. <IMAGE>

Description

LOCKING DEVICE This invention relates to a locking device for securing a vehicle towing arrangement such as would be commonly found on a caravan trailer or similar vehicle intended for connection to a motor vehicle.

The common configuration for vehicle towing arrangement for caravans or trailers is to provide a hook portion on a first vehicle for example a motor car or other motor driven vehicle. This hook portion extends behind the car and includes an upwardly projecting spigot having at a top end thereof a partially spherically protrusion. A hook receiving portion is carried by a second vehicle for example a caravan or trailer and includes a bar or other member projecting from one end of the second vehicle. The bar has a hemi-spherical locating hole in its underside such that it may be placed over and enclose the partially spherical protrusion of the hook portion. Spring loaded clamping means are provided within or on the bar such that a clamping device or arm is arranged to be closed around the spherical protrusion to retain it therein against the normal stresses and strains of use.Release of the clamping device will permit the bar to be lifted clear of the spherical protrusion and the two vehicles separated.

The securing of a vehicle towing arrangement such that the vehicle cannot be attached by unauthorised persons to other vehicles having corresponding hook portions is a major security problem with this type of vehicle. It will be appreciated that it would be quite easy in the absence of any security devices to attach a car or other motor vehicle to a caravan drive the caravan away so that it may be opened and its contents stolen or the caraven itself resold at leisure. Such consideration also apply to other towed vehicles for example small trailers intended for towing behind motor cars or similar sized vehicles.

One known way in such arrangements may be secured is to provide a locking bar or pad lock arrangement securing the spring loaded clamping means. One problem inherent with such an arrangement is that for ease of access the release catch for the spring loaded clamping means is located on the top of the bar or member of the hook receiving portion. Thus the padlock or lockable bar is exposed and can be removed for example by use of a hack saw or similar article.

The use of a locking mechanism acting directly on the spring loaded clamping means and included within the bar construction would overcome this problem however the resulting structure would be fairly complex and would not lend itself to refitting to existing vehicle towing arrangements.

It is an object of the present invention therefor to provide a locking device for a vehicle towing arrangement which is simple to use and can be adapted to fit existing arrangements with only minor modifications thereof.

With this object in view the present invention provides a locking device for a vehicle towing arrangement having a hook portion on a first vehicle and hook receiving portion on a second vehicle, the locking device being shaped to be received by and within the hook receiving portion and provided with lockable means operative to secure the device to the hook receiving portion.

In a first aspect of the invention the locking device is provided with a rotatable screw threaded rod which is adapted to engage in a corresponding threaded hole in the hook receiving portion, the rod being attached to a key operated mechanism such that rotation of a key inserted therein will cause corresponding rotation of the rod.

The locking device of the invention is intended to be inserted into the hook receiving portion and to at least partially fill or block said portion. Operation of the key operated mechanism would then securely attach the locking device within the hook receiving portion by engagement of the rod in the hole. Once the key is removed therefrom it will not be possible to remove locking device without manipulation of the key operated mechanism. As the locking device completely blocks the hook receiving portion it will not be possible to attach any vehicle having such a blocked receiving portion to another vehicle having a normal corresponding hook portion. Thus unauthorised towing of a vehicle fitted with such a locking device is prevented.

In order to prevent rotation of the locking device within the hook receiving portion during operation of the key mechanism it is preferable to provide at least one pin protruding from a surface of the locking device which pin locates in a corresponding hole provided in the inner surface of the hook receiving portion. In this way rotation of the locking device about the axis formed by the screw threaded rod is prevented.

Preferably the locking device is at least partially spherically shaped so as to more or less completely block the hook receiving portion once it is inserted therein. Additionally with such a configuration it is possible to release the spring loaded clamping means to engage around the locking device and assist its retention therein.

A second aspect of the invention provides a locking device having a fixed screw threaded rod which is adapted to engage in a corresponding threaded hole, the device also having an extensible pin connected to a key operated mechanism, the pin when extended out of the device locating in a second hole in the receiving portion so as to prevent rotation of the device and the screw threaded rod.

The invention will be described further by way of example with preference to the accompanying drawing which is a sectional view of a first preferred embodiment of the invention located in a standard hook receiving portion of a vehicle towing arrangement.

In the single drawing a hook receiving portion of a vehicle towing arrangement is referred to generally by the reference numeral 10. The hook receiving portion comprises a carrying bar or member 12 to which is attached a hook receiver 14. The hook receiver 14 provides a hemi-spherical resess 16 on the underside of the receiver 14 such that the hook receiving portion 10 may be placed over a correspondingly shaped hook portion (not shown) which will then be seated within the hemispherical recess 16.

A handle 18 is attached to a clamp 20 which partially protrudes into the hemi-spherical recess 16.

The handle 18 is pivoted 22 to the receiver 14 so that the clamp 20 may be moved with respect to the hemispherical recess. A spring or other similar biassing means (not shown) is attached to the handle 18 such that it is biassed into its lowered position with the clamp 20 protruding into the recess 16.

It will be appreciated that with this arrangement when the handle 18 is lowered the clamp 20 will be effective to grip and retain a partially spherical protrusion which is located in the hemi-spherical recess 16. Thus a hook portion attached to a first vehicle (not shown) can be retained within the hook receiving portion 10 of a second vehicle so that towing of the second vehicle may be undertaken.

Removal of the located hook portion requires movement of the clamp 20 and consequent raising of the handle 18 against the action of the attached spring means. In order to simplify removal of the hook portion a catch member 24 is pivoted to 26 to the receiver 14.

The catch member 24 is provided with an upper locating hole 28 and a lower locating hole 30 which engages with a projecting lug 32 on the handle 18.

Thus the lower hole 30 may be engaged with the lug 32 when the handle 18 is in its lowered position with the clamp 20 protruding into the recess 16.

Alternatively the lug 32 may be engaged in the upper hole 28 thus holding the handle and the attached clamp 20 in an open position against the action of the spring biassing means. Preferably the pivot 26 is also provided with further spring biassing means operative to urge the catch member 24 towards the handle 18 such that engagement of the lug 32 with its respective hole 28 or 30 is maintained.

It will be appreciated that it is therefor a simple matter to attach a non secured vehicle towing arrangement to a hook receiving portion on an additional vehicle by simple operation of the handle 18. Normally it would be possible to secure this handle by way of a padlock or similar extending through a hole (not shown) in the handle and a corresponding hole in the receiver 14. This will then effectively lock the handle 18 in either its raised or lowered position as desired thus making attachment of the receiving portion to a new hook portion impossible. However the placement of such corresponding holes in the handle 18 and receiver 14 would have to be of the upper side of the receiving portion 10. This would expose the lock of the padlock to tampering and would also make it possible for the padlock to be forceably removed for example by way of a hack saw or similar.

In order to overcome this the invention provides a locking device 33 in the form of a partially spherical body 34 configured to locate in the recess 16 in the hook receiving portion 10. Thus when the handle 18 and attached clamp 20 are lowered the locking device 33 will be retained within the recess 16.

In order to securely lock the device 33 in the recess 16 a screw threaded hole 36 is provided in the receiver 14 communicating with the recess 16. A correspondingly threaded bar 38 is carried by the device so as to extend beyond its partially spherical body surface Rotation of the screw threaded bar 38 will cause engagement with the thread on the inner surface of the hole 36 thereby drawing the device 33 into the recess 16 and holding it therein. Rotation of the bar 38 is preferably effected by way of an attached rod 40 which extends diametrically and rotatably through the centre point of the partially spherical body 34. The end of the rod 40 is attached to a lock mechanism 42 such that the rod 40 may only be rotated by insertion of key (not shown) into the lock mechanism 42.

In order to prevent rotation of the body 34 during rotation and engagement of the bar 38 into the hole 36 a pin 44 is preferably provided protruding from the hemispherical body and preferably off centre thereof. This pin 44 locates in a corresponding hole 46 provided in the receiver 14. Thus rotation of the body 34 about the axis of the rod 40 is prevented.

It will be understood that insertion of the device 33 into the recess 16 and consequent location of the pin 44 in hole 46, engagement of the screw bar 38 into the hole 36 by rotation of the rod 40 will cause the device 33 to completely block the recess 16 thus making it impossible to attach the hook receiving portion 10 to a hook portion on another vehicle. Furthermore the lock mechanism 42 is placed below the receiver 14 and the body 34 of the device is entirely enclosed in the recess 16 thus making tampering with the mechanism 42 or physical removal of the device 34 difficult.

In an alternative embodiment of the invention the screw threaded rod is fixed relative to the locking device body. Thus rotation of the whole device will cause engagement of the rod with its associated threaded hole. In order to secure the locking device in place the key operated mechanism is associated with an extensible pin such that rotation of a key in the mechanism will cause the pin to extend and project beyond the device's surface. A second hole is provided in the receiving portion to receive the extended pin thus preventing rotation of the locking device in the hook receiving portion.

In order to ensure that the pin is correctly located the locking device is preferably provided with a spring loaded locating pin or ball bearing which engages a suitably positioned depression in the receiving portion's inner surface. It is therefore possible to ensure that the device is correctly aligned before the pin is extended into its locating hole.

The invention is not confined to the foregoing details and variations may be made thereto within the scope of the invention.

Claims (6)

1. A locking device for a vehicle towing arrangement having a hook portion on a first vehicle and hook receiving portion on a second vehicle, the locking device being shaped to be received by and within the hook receiving portion and provided with lockable means operative to secure the device to the hook receiving portion.

2. A locking device as claimed in claim 1 wherein a rotatable screw threaded rod is provided which is adapted to engage in a corresponding threaded hole in the hook receiving portion, the rod being attached to a key operated mechanism such that rotation of a key inserted therein will cause corresponding rotation of the rod.

3. A locking device as claimed in claims 1 or 2 in which the locking device further includes at least one pin protruding from a surface of the locking device which pin locates in a corresponding hole provided in the inner surface of the hook receiving portion.

4. A locking device as claimed in claims 1, 2 or 3 in which the device is at least partially spherically shaped so as to more or less completely block the hook receiving portion once it is inserted therein.

5 A locking device as claimed in claim 1 which includes a fixed screw threaded rod which is adapted to engage in a corresponding threaded hole, the device also having an extensible pin connected to a key operated mechanism, the pin when extended out of the device locating in a second hole in the receiving portion so as to prevent rotation of the device and the screw threaded rod.

6. A locking device substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.