GB578693A - Brakes for vehicles - Google Patents

Abstract

578,693. Brakes. DUNCAN, W. O. (Bendix Aviation Corporation). Sept. 11, 1942, No. 12832. [Class 103 (i)] Brake applying means comprises a pair of levers each engaging a brake shoe at an intermediate point at one end and connected by a floating pivot through which force applied to one lever at the other end and acting on one shoe reacts on the other lever to apply force to the other shoe. The levers may be arranged in a plane, parallel, at right angles or oblique to the plane of the back plate. The brake-shown is similar to that described in Specification 499,598 in which a pair of shoes 52; 54 are arranged each to anchor at one end or the other according to the direction of rotation of the drum and comprising pairs of bell-crank levers 102, 104, 114, 116 pivoted at 106, 122 near the ends. and on each side of the shoes and connected by struts 118. The levers 114 engage an adjusting device comprising, plungers 136 slotted to receive the shoe ends and: which can be moved apart by the conical head 138 of a pin screwed into the fixed casing 56. The bell-cranks 102, 104 are operated by a pair of levers 60, 62 that are respectively mounted on a fixed pivot 66 and connected to an operating; cable. 78 and are connected together by a floating pivot 64. The levers bear upon a pair of tappets 92 slidable in a fixed housing 82 and engaging the bell cranks and forked at the ends to receive the shoe ends and abutments 100 which form part of sleeves 98 secured in the housing and upon which the shoe ends may bear. When the cable 78 is pulled an equalized force is applied to the tappets 92 and thus to the bell-cranks which by pivoting on the tappets and the plungers 136 apply the shoes to the drum. One shoe then anchors on one of the abutments 100 and the other on the housing 56. To render the levers 104 adjustable relatively to the shoes the pivots 122 each comprise a pin 126, Fig. 7, bearing an eccentric boss 124 disposed within the shoe web and carrying a bush 128 for each bell-crank. The pin is locked against rotation after an adjustment by a nut 134 thereon. In a modification in which single bellcranks are disposed between double webs of the shoes at each end adjustment of a bell-crank is effected by forming the pin within a central boss toothed on its periphery for engagement with a toothed hole in the boss of the bell-crank. Modifications are shown in which levers similar to the levers 60, 62 are arranged at right angles and oblique to the back plate and in which the shoes are mounted on fixed pivots and are engaged directly by the levers. The pivot 66 of the lever 62 instead of being fixed as shown may be connected to operating means which may be used as an alternative to the cable 78.