GB2077867A

GB2077867A - Safety Braking Device

Info

Publication number: GB2077867A
Application number: GB8115119A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-05-27
Filing date: 1981-05-18
Publication date: 1981-12-23

Abstract

A safety device (1) for use in towing a trailer with a braking system comprises a first member (2) adapted for attachment to or secured to the trailer and a second member (3) adapted for attachment to the towing vehicle and to the trailer braking system. The first (2) and second members (3) are relatively movable between a non-braking position and a braking position in which the trailer braking position is activated should the towing connection between the trailer and towing vehicle be broken. Locking means (4, 6, 9) are arranged to lock the first (2) and second (3) members in a braking position. <IMAGE>

Description

SPECIFICATION Safety Device The present invention relates to a safety device and more particularly relates to a safety device for use with trailers having a braking system such as those which are towed by a tractor or other vehicle.

According to the present invention there is provided a safety device for use in towing, by means of a towing connection to a towing vehicle, a trailer having a braking system, which comprises a first member adapted for attachment to or secured to the trailer and a second member adapted for attachment to the towing vehicle and to the trailer braking system, the first and second members being relatively movable between a non-braking position and a braking position which the trailer braking system is actuated should the towing connection between the trailer and the towing vehicle be broken, and latching means arranged to hold the first and second members in a braking position.

Preferably the second member is relatively movable to the first member in a direction substantially parallel to the first member and conveniently, the first member is adapted for attachment to or secured to the tow bar of the trailer.

The latching means may comprise formations on a surface of the second member and a latching element arranged to engage with at least one formation should the towing connection between the trailer and the towing vehicle be broken. In such embodiments of the present invention the latching means may comprise ratchet and pawl means, the contact portion or contact edge of the pawl desirably being biassed into contact with the surface of the second member comprising formations by biassing means.

When in use, the second member of the safety device of the present invention includes first connecting means for attachment to the towing vehicle and second connecting means for attachment to the trailer braking system. These connecting means are preferably flexible connecting means such as cable. It is desirable for the second connecting means to have a higher tensile strength than the first connecting means so that the connection between the second member and the towing vehicle will break before the connection between the second member and the braking system if there is continued separation of the towing vehicle and the trailer when the normal towing connection therebetween breaks.

It will be understood from the foregoing that the first and second members of the safety device of the present invention are freely relatively movable from a non-braking position to a braking position when the towing connection breaks but when in a braking position, relative movement thereof to a non-braking position is prevented by the latching means. If the towing connection between the towing vehicle and the trailer brakes the vehicle and trailer will move apart which causes relative movement of the first and second members from their normal non-braking position by virtue of the first connecting means between the vehicle and the second member and the second connecting means between the second member and the braking system of the trailer.

Reference is now made to the accompanying drawing which shows a preferred safety device of the present invention. The safety device generally designated 1 has a first member 2 which is of elongate shape and which has a rectangular cross-section. The first member 2 has fixedly attached thereto two channel-pieces 10 in which is slidably received a second member 3. The second member 3 is also elongate and of rectangular cross-section. One of the channel members 10 has a pivot 1 7 to which is pivotally connected a pawl 4 having a contact edge 6 which contacts the surface 8 of the second member 3, and a projecting member 5. A coil spring 7 is connected at one end to a hole 1 3a in the projecting member 5 and at its other end to a notch 13 in a member 12 which projects from, and is attached to, the first member 2.The spring 7 biasses the contact edge 6 of the pawl 4 into contact with the surface 8 of the second member 3 in which surface 8 there are saw-tooth formations 9. Each end of the second member 3 has a clevis 15, 16, the end carring the clevis 1 5 being that end of the safety device 1 which is nearest the towing vehicle when in use.

In use, the device 1 which is preferably made of steel is normally attached to the tow bar of the trailer and one end of a cable (not shown) is attached to the clevis 1 5 and the other end thereof is attached to the towing vehicle. One end of a stronger cable (not shown) is attached to the clevis 1 6 and the other end thereof is attached to the brake actuating means of the trailer brakes.

Should the tow bar break or else become disconnected from the towing vehicle then the cable attached to the clevis 1 5 will become taut due to relative movement apart of the towing vehicle and trailer and the member 3 will move in the direction of arrow A. It will be seen from the accompanying drawing that movement in the direction will bring the formations 9 into the vicinity of the contact edge 6 and will automatically actuate the brakes of the trailer by transmission through the cable attached to the clevis 1 6. Should the cable attached to the clevis 1 5 then break, movement of the second member 3 in the direction of arrow B with would turn off the brakes of the trailer is impossible since the contact edge 6 will have engaged one of the formations 9, and it will additionally be positively engaged by means of the bias produced by the coil spring 7.

In some applications it is advantageous to provide a stop member between the clevis 1 5 and the channel member 10 nearest thereto. The purpose of this is to limit excess movement of the second member 3 in the direction of the arrow B.

For example, the position of the device as shown in the drawing will allow some movement of the second member 3 in the direction of the arrow B since the contact edge 6 is merely in contact with the surface 8 and there is no engagement therebetween. A stop member aforementioned would thus eliminate excess movement in direction B.

Claims

1. A safety device for use in towing, by means of a towing connection to a towing vehicle, a trailer having a braking system, which comprises a first member adapted for attachment to or secured to the trailer and a second member adapted for attachment to the towing vehicle and to the trailer braking system, the first and second members being relatively movable between a non-braking position and a braking position in which the trailer braking system is actuated should the towing connection between the towing vehicle and the trailer be broken, and latching means arranged to hold the first and second members in a braking position.

2. A safety device as claimed in Claim 1 wherein the second member is relatively movable to the first member in a direction substantially parallel to the first member.

3. A safety device as claimed in Claim 1 or Claim 2 wherein the latching means comprises formations on a surface of the second member and a latching element arranged to engage with at least one formation should the towing connection be broken.

4. A safety device as claimed in Claim 3 wherein the latching means comprises ratchet and pawl means.

5. A safety device as claimed in any of Claims 1 to 4 wherein the first member is adapted for attachment to or secured to the tow bar of the trailer.

6. A safety device as claimed in any of Claims 1 to 5 wherein the second member includes first connecting means for attachment to the towing vehicle and second connecting means for attachment to the trailer braking system.

7. A safety device as claimed in Claim 6 wherein the first and second connecting means are each flexible connecting means.

8. A safety device as claimed in Claim 6 or Claim 7 wherein the second connecting means has a higher tensile strength than the first connecting means.

9. A safety device for use in towing a trailer by a towing vehicle substantially as herein described with reference to and as shown in the accompanying drawings.