GB2245240A - Anti-theft device for trailers - Google Patents

Abstract

A device is provided for locking the brakes of a trailer to prevent theft thereof, which is intended to engage both a pivoting lever 5 and a flange element 9 of the trailerws brake connection means 7 and thereby to prevent relative movement in a specific sense of the lever 5 and the brake connection means 7. A pair of angled strip elements 15, 29 have slots 18, 19, 27, 28 for reception of the lever 5 and the brake connection means 7, and lateral openings 20, 21, 31, 32 which coincide when the device is in one condition to allow movement of the lever 5 and the brake connection means 7 into the slots 18, 19, 27, 28. The device can then be locked in a second condition wherein the lever and connection means cannot escape. <IMAGE>

Description

ANTI-THEFT DEVICE FOR TRAILERS This invention relates to an anti-theft device for trailers and especially though not exclusively to an anti-theft device for trailed caravans.

Though several types of immobilising antitheft devices have been proposed for trailers, such as wheel clamps and hitch locks, these tend to be complex and/or unsuccessful.

The present invention is a device adapted to immobilise the trailer by acting on its braking system.

Trailers and in particular caravans have servo braking systems which are responsive to relative acceleration of the trailer relative to the towing vehicle. A shaft attached to the hitch point is displaced by that relative acceleration of the trailer to bear against a lever which then tends to apply the brakes of the trailer thereby to restore it to the speed of the towing vehicle.

Such trailers are additionally equipped with a hand-operable lever (which may be the same as or different from the lever operated by the shaft) whereby the brakes of the trailer can be permanently applied when it is parked.

The present invention is intended to lock the brakes in the parked condition.

To this end, the invention provides a device intended to engage with a pivoting lever of a servo brake mechanism at one side of its pivot axis and with a connecting rod extending from that lever at the other side of its pivot axis to brakes of the trailer and prevent relative displacement of the connecting rod and of the lever in a sense which would represent release of the brakes of the trailer.

The device has a yoke action, being fitted by the user over the one arm of the lever and over the connecting rod (which are of course permanent parts of the trailer) and then being secured in such a way that it cannot be released except by the owner. A particular form of yoke is an angled strip element having elongate slots for reception of the lever and the connecting rod and lateral openings for allowing the yoke to be fitted over those elements; and the securing device is a second angled strip with elongate slots and with non-coincident lateral openings, lockable onto the first strip in such a way as to enclose the lever and the rod within the elongate openings.Further superimposed openings in the two strips allow for the passage of locking means such as the arm of a padlock so that they cannot be separated, and the lever and rod cannot be relatively freed except after removal of that lock.

A particular embodiment of the invention will now be described with reference to the accompanying drawings, wherein: Figure 1 is a sketch side elevation of the servo lever and handbrake lever mechanism of a trailer, Figure 2 is a perspective view of two parts of an embodiment of anti-theft device for that trailer, Figure 3 is a perspective view of the two parts put together, and Figure 4 is a diagrammatic perspective view of the device fitted.

The particular embodiment to be described has been designed to fit an Al-ko chassis which is the commonest British and European caravan chassis. The principle embodied is however applicable to other chassis and braking arrangements.

Figure 1 shows diagrammatically these arrangements. A tube 1 which is fixed to the chassis of a trailer has within it a shaft 2 which is spring-loaded towards a forward (left-hand) position. When it is hitched up to a towing vehicle and the trailer tends to accelerate relative to the towing vehicle, i.e. tends to move to the left in Figure 1, the shaft moves in the tube against the loading of its spring and engages against the nose 4 of one arm 3 of a brake lever 5 to the other end of which is attached through a lost motion yoke 6 a connecting rod 7 extending to the brakes of the trailer.

The rod is connected to an energy storing spring-loaded cylinder 8 the rear (right-hand) end of which is engaged by an angle part 9 of a connecting plate 10 pivoted at 11 to a lower end 12 of a handbrake lever 13 which is pivoted, coaxially with -the lever 5, on the chassis of the trailer at 14.

When the trailer is parked the handbrake lever 13 is pulled upwards to the dotted line position thereby moving the connecting plate 10 forward and pulling the connecting rod 7 forward through the action of the angle part 9 and the energy storage cylinder 8. This forward movement also allows the lever 5 to rotate to the dotted line position seen in the drawing.

The present embodiment of the invention is to act to maintain the angle part 9 and the upper arm 3 of the lever 5 in a positional relationship which maintains the brakes applied. Exactly the same effect may be obtained if the device were to act on the handbrake lever 13, and in those cases where the handbrake lever 13 and the brake lever 5 are a single entity.

As seen in Figure 2, the anti-theft device has two parts. To form a yoke between the angle part 9 and the lever 5, a strip 15 of steel is bent in a rightangle with a major arm 16 and a minor arm 17. Each arm has an elongate slit 18 and 19 respectively and each of these has a lateral access slot 20 and 21 respectively.

The major arm 16 has a hole 22 for receiving a locking device such as the arm of a padlock and may have another aperture 23 to which a nut 24 is welded.

The strip 16 may be reinforced by a side plate 25 on one side of its angle.

A second part 26 of the anti-theft device is also a right-angled strip of dimensions to fit outside the strip 16. It has elongate slits 27, 28 in its major arm 29 and minor arm 30 respectively and these register generally with slits 18 and 19. The slits 27 and 28 have respective lateral access slots 31, 32 respectively but these do not coincide with corresponding slots 20 and 21 on the part 16. Aperture 33 in the arm 29 is to register with aperture 22 and aperture 34 with aperture 23. A side plate 35 reinforces the angle of this strip.

Figure 3 shows (with one of the side plates omitted for clarity) the two strips in overlying relationship and showing how while slits 18 and 27 on the one hand and 19 and 28 on the other correspond, the overlying of the two strips effectively closes those slits since the access slots 20 and 31 or 21 and 32 no longer coincide. If now the two parts are secured together for example by passing a bolt through aperture 34 to engage nut 24 or by passing the arm of a padlock through the registering holes 33, 22 and then locking the padlock, they will prevent relative displacement of what is within those slits.

The slits 27 and 18 are to receive the arm 3 of the servo lever 5 and the slits 19 and 28 are to receive the connecting rod, to surround the latter behind (i.e. to the right-hand of in Figure 1) the angle arm 9. Since the angle arm 9 is indirectly attached via cylinder 8 to the connecting rod and the connecting rod originates from the lever 5 at a different side of pivot 14 than does the arm 3, the effect of the yoke is that the brakes of the trailer cannot be released except by cutting the connecting rod behind where the device is fitted.

To fit the device, first the strip 16 is taken and fitted around lever arm 3 and rod, and then the second strip 26 and the two secured together either by a bolt through aperture 34 or by a padlock through holes 22,33 or both.

Claims (6)

CLAIMS:

1. A device for locking the brakes of a trailer, having means for engaging a pivoting lever of a brake mechanism at one side of its pivot axis and means for engaging an element of a brake connection means, which connection means is connected to the pivoting lever at a second side of its pivot axis, thereby to prevent relative displacement of said pivoting lever and said brake connection means in a sense which would represent release of the brakes of the trailer.

2. A device according to claim 1 which includes a yoke having slots for reception of the pivoting lever and the brake connection means and lateral openings for allowing the yoke to be fitted over said pivoting lever and said brake connection means, and means for retaining the lever and brake connection means in the slots whereby to prevent the said relative displacement.

3. A device according to claim 2, wherein the retaining means is a securing device with slots and lateral openings, the lateral openings of the yoke and-the lateral openings of the securing device being coincident when the securing device is in a first position relative to the yoke and non-coincident when the securing device is in a second position relative to the yoke, and the slots being at least partly-coincident in both positions, the yoke and securing device being lockable into said second position thereby to enclose the lever and the brake connection means within the slots.

4. A device according to claim 3, wherein the yoke and securing device are each angled strip elements having the slot for reception of the pivoting lever in one leg thereof and the slot for reception of the brake connection means in a second leg thereof, and having openings for the passage of locking means, which openings are coincident when the securing device is in said second position relative to the yoke.

5. A device according to claim 4, wherein at least one of the strip elements has a reinforcing side plate which serves to maintain the angle in the strip element.

6. A device according to any one of the preceding claims as described herein with reference to the accompanying drawings.