GB518137A - Automatic braking means for a power- or man-hauled trailer vehicle - Google Patents

Abstract

518,137. Vehicle brakes. LISTER & CO., Ltd., R. A., and ASHWORTH, P. B. Aug. 29, 1938, No. 25262. [Class 103 (i)] A trailer adapted for man or power hauling by means of a drawbar pivotally connected with lost motion to the trailer has a brake biassed on by a spring and connected to the drawbar in such manner as to be released when the latter is in an inclined man-hauling position and applied or able to be applied when the drawbar is swung into a vertical parked position or into a horizontal power-hauling position. As applied to a trailer with steerable turntable, arms 12 on the latter carry pivot pins 17 engaging slots 16 in bifurcations of the drawbar 14 which has a transverse bar 15 for coupling to the tractor or for man hauling, a brake rod 19 being connected at one end to a lug 18 on the drawbar and at its other end to a transverse balance bar 21 each end of which is connected to a brake lever system 23-25 operating a brake cam and biassed by a strong spring 26 constantly tending to apply the brake. When the drawbar is moved into vertical parking position, as shown in full lines in Fig. 3, the brake rod 19 moves into position allowing spring 26 to actuate rod 23 into brake applying position but when the drawbar is moved into the dotted line position suitable for man-hauling the brake rod 19 pulls the rod 23 to the right and releases the brake ; in this position a pin 29 on the drawbar engages an arcuate member 28 on one of the arms 12 to limit the upward and outward movement of the drawbar. For power hauling the drawbar is moved into horizontal position, Fig. 4; the pin 29 being then released from the arcuate member 28 and the brake springs acting to apply the brakes except when the drawbar is pulled forward by the hauling motion as shown by the dotted lines and the brakes are thereby released. To prevent buckling of the brake rod 19 or hammering brake action if the drawbar were allowed to fall too low the brake rod 19 is connected to the lug 18 by a sliding joint 31. In the rear wheel brake connection shown in Fig. 5 the balance bar 21 is interposed between a central multiplying lever 23 and the brake cam levers and two small guide wheels 33 are provided to ensure the brake cable 34 passing through the steering centre. In another rearwheel brake construction, Fig. 7, the brake levers 25 are actuated by a balance bar 21 connected to the brake lever 19 by bell crank levers 35, 36 connected by a link 37 disposed to be in the rotational axis of the turntable.