GB2286370A - Ball Hitch Lock - Google Patents

Abstract

The lock comprises a housing 10 which is permanently secured, eg. by shear bolts, to the body of the hitch, and, carried by the housing, a locking bar 30 which is operable by means of a lock and key mechanism 26 to drive the locking bar between a retracted, non-operative position and a projected, operative position in which it prevents lifting of the clasp handle of the ball hitch, which prevents the hitching and unhitching of the ball hitch. The locking bar 30 may also prevent release of a safety catch on the clasp handle, where provided, of the ball hitch in order to prevent lifting of the clasp handle. <IMAGE>

Description

Ball Hitch Locking Device This invention relates to a ball hitch locking device.

Ball hitches are commonly employed to enable vehicles to tow caravans, horse boxes and trailers, which trailers may themselves carry a wide variety of equipment ranging from small boats to apparatus such as portable generators in common use in the construction and engineering industries.

It is not uncommon for such trailers to be stolen, not only when a trailer is left standing alone, but also when a vehicle to which a trailer is hitched is temporarily parked.

An Aim of the invention is to provide a ball hitch locking device which makes the theft of such trailers much more difficult.

A ball hitch comprises a towing ball mounted on the rear of the towing vehicle and a ball clasp attached to the towed vehicle. Typically, the clasp has a body formed with a socket for engaging around the ball and a handle which has to be lifted away from the body to retract a securing element within the socket and thereby enable the socket to be disengaged from the ball. Commonly, a safety lever has to be operated before the handle can be lifted to the extent necessary to achieve disengagement of the socket from the ball. Normally, however, there exists an amount of free play between the socket and ball without effecting disengagement, in order to permit relative up-and-down movement when the towed vehicle is being towed over uneven road surfaces.

According to the invention, there is provided a ball hitch locking device which comprises a housing which is adapted to be permanently fixed to the body of the hitch clasp, a locking element which is movable between a first position in which it prevents lifting of the clasp handle to the extent necessary to enable the socket to be engaged with and disengaged from the ball and a second position in which such engagement and disengagement is permitted, and a lock which controls or permits the movement of the locking element between its two positions.

The lock is preferably a key-operable lock. Rotation of the key may then be utilised as a driving force for the locking element.

The locking element may move in a straight or curved path, and it may in its first position either restrict lifting of the clasp handle directly or it may prevent operation of the safety lever.

The housing preferably fixes to the clasp body by means of shear-off bolts, i.e. bolts having heads which shear away after the bolts have been fully tightened, so that the body member is then permanently fixed in place.

The housing preferably has at least two parts, including a main upper part and a secondary lower part which fix together around the clasp body so as to be immovable relative to the clasp body in three dimensions.

The clasp is normally fixed to the damper arm of the trailer, and the locking device of the invention most preferably secures to the clasp body in a manner which does not hinder servicing of the damper.

Most preferably, in its first or locking position, the locking element does not restrict the normal free play permitted between the ball and socket of the hitch.

The lock preferably drives the locking element through a cam which, in the locked condition, has an edge lying in abutting engagement with the interior of the body member, so that the locking element cannot readily be forced towards the second or unlocked position without use of the lock and key.

A locking device in accordance with the invention is now described by way of example with reference to the accompanying drawings, all somewhat diagrammatic, and in which: Figure 1 is a side elevational view of the main part of the housing of the locking device; Figure 2 is a plan view thereof; Figure 3 is a front view; Figure 4 shows the lower part of the housing; and Figure 5 illustrates a possible modification.

The form of a ball hitch has been previously described.

On the trailer, it comprises a clasp having a body incorporating a socket for engagement around the ball.

The illustrated locking device is intended to be permanently fixed to this clasp body.

The locking device comprises a housing having a main part 10 shown in Figures 1 to 3. This part 10 is shaped to seat astride the clasp body, and cooperates with a lower body part 12, shown in Figure 4, completely to surround the clasp body. The part 10 also includes front support bars 14 which fix to the front of the clasp body, so that the locking device fixes to the clasp body with security against movement in three dimensions. This fixing is achieved by means of shear-off bolts, typically as indicated at 16 in Figure 1, so that the locking device cannot be unbolted from the clasp body after attachment.

Shaped side plates 18 of the lower housing part fit inside the walls 20 of the upper housing part 10, so that the two housing parts cannot be levered apart. Additionally, the housing parts are machined of tempered steel to prevent cutting with a hacksaw or the like.

As shown at 22 in Figures 1 and 2, the housing 10, 12 has cut away portions to allow access to damper securing bolts.

In the case where no such securing bolts are provided, the support bars 14 which bolt to the clasp body are preferably replaced by a U-piece 24, as indicated in Figure 5.

The uppermost region of the housing houses a key-operable cam lock 26. The lock cam 28 is utilised to drive a locking bar or bolt 30 which projects through a slot 32 in the front of the housing. When the key is rotated, the locking bolt 30 is driven side-to-side relative to the housing, between an off-centre inoperative position and a central operative position. In the operative position, the locking bolt 30 lies just above the lifting handle of the body clasp immediately to the rear of the normally provided security lever, thus preventing operation of the locking lever as well as preventing lifting of the clasp handle sufficiently to release the socket in the clasp body from the towing ball, or to engage the socket over the ball. The locking bolt 30 does not, however, restrict the free play between the ball and socket necessary to the towing function.

It will be appreciated that the lock is effective both when the towed vehicle is detached from the towing vehicle and stands alone, as well as when the towing vehicle and the towed vehicle are parked together. It is also effective for hitch clasps which are not provided with a security lever for the clasp lifting handle.

Additional securing is achieved, in the illustrated arrangement, by abutment of an edge of the lock cam 28 with the interior wall of the housing in the locked condition, as indicated in dashed line in Figure 2.

Various modifications of the illustrated arrangement are possible within the scope of the above-defined invention.

For example, hitch clasps are available in various sizes and shapes, and the configuration of the housing of the locking device is designed accordingly. Moreover, it is not essential for the key-operable lock to be a cam lock which directly drives the locking bolt. The lock may serve, for example, to prevent or to permit a locking bolt to be moved in a separate operation.

Claims (10)

Claims

1. A ball hitch locking device comprising a housing which is adapted to be permanently fixed to the body of the hitch clasp and, carried by said housing, a locking element which is movable between a first position in which it prevents lifting of the clasp handle to the extent necessary to enable the socket to be engaged with and disengaged from the ball and a second position in which such engagement and disengagement is permitted, and a lock which controls or permits the movement of the locking element between its two positions.

2. A device according to claim 1, in which the lock is a key-operable lock.

3. A device according to claim 2, in which rotation of the key is utilised as a driving force for the locking element.

4. A device according to any of claims 1 to 3, in which the locking element moves in a straight or curved path, and in its first position either restricts lifting of the clasp handle directly or prevents operation of the safety lever.

5. A device according to any of claims 1 to 4, in which the housing fixes to the clasp body by means of shear-off bolts, i.e. bolts having heads which shear away after the bolts have been fully tightened, so that the housing is then permanently fixed in place.

6. A device according to any of claims 1 to 5, in which the housing has at least two parts, including a main upper part and a secondary lower part which fix together around the clasp body so as to be immovable relative to the clasp body in three dimensions.

7. A device according to any of claims 1 to 6, in which, when the clasp is fixed to the damper arm of the trailer, the locking device secures to the clasp body in a manner which does not hinder servicing of the damper.

8. A device according to any of claims 1 to 7, in which the locking element does not restrict the normal free play permitted between the ball and socket of the hitch when said element is in its first or locking position.

9. A device according to any of claims 1 to 8, in which the lock drives the locking element through a cam which, in the locked condition, has an edge lying in abutting engagement with the interior of the body member, so that the locking element cannot reaidly be forced towards the second or unlocked position without use of the lock and key.

10. A locking device for a ball hitch substantially as hereinbefore described with reference to the accompanying drawings.