GB394323A - Improvements in or relating to brake mechanism for use with trailers - Google Patents

Abstract

394,323. Brakes for trailers. CLARKE, C. V., 171, Tavistock Street, Bedford. Sept. 14, 1931, No. 25740. [Class 103 (i).] A trailer brake is released bv movement of the tow-bar due to forward movement of the tractor and comprises means, e.g. fluid-pressure for holding the brake in released position, which fluid-pressure is released by the driver to affect application of the brake. The drawbar 1 slides in a housing 6 and has a piston 2 sliding in a cylinder 3 on the trailer. A collar 4 fixed to the draw-bar bears on a shoulder on a sleeve 5 connected by a hub 14 and a liner 15 to the brakes. A spring 7 is compressed between the sleeve 5 and the bearing 6 when the tractor moves forward and oil is drawn through valves 9, 10 from a reservoir 8 into the cylinder 3 and holds the trailer brakes released. The brake application is initiated by a Bowden control 13 from the tractor, wbich is adapted to open the valves 9, 10 and release the oil into the reservoir and allow the spring 7 to apply the brakes until a further acceleration of the tractor releases the brakes. When the tractor is stopped suddenly, overrunning of the trailer produces a further braking through a spring 19 between the collar 4 and a sleeve 18 fixed to the sleeve 5. The sleeve 18 finally comes against a buffer stop 24 to limit the movement of the draw bar. The extent to which the spring 19 is compressed may be regulated by an adjustment device. Seating in the valve 10 is the valve 9 which is small and can be easily opened against the fluid-pressure which is partially relieved and allows the valve 10 to be easily opened by the collar 12 on the rod of the valve 9. To the liner 15 is secured an extension 20 attached to the cylinder portion 21 of a shock absorber which allows the trailer to be started without shock. The parts of the Bowden wire 13 are detachably connected by a hook 31 and pin 32 to the valve lever 12<1> and a wing nut 34 to a fixed part. The spring 7 may be replaced by a spring 30 where a minimum length of draw-bar is desired. In a modification the spring 7 is replaced by three springs, a cable connects the sleeve 5 to the brakes and the shock absorber is arranged over the springs. Attached to this cable 1 is a cable connected to a collar adapted to be turned by a key to release the brakes by hand when the trailer is detached. The shock-absorber is mounted between the collar 5 and the bearing 6. The valves 9, 10 may be substituted by valves consisting of inner and outer forked sleeves. If the trailer breaks away the brakes will be applied by the tension on the cable 13 before it breaks.