GB703176A - Improvements relating to brakes for trailer vehicles - Google Patents

Abstract

703,176. Trailer-vehicle brakes. BATE, B. DIXON-. April 21, 1952 [April 21, 1951], No. 9344/51. Class 103(1) A brake system for a trailer vehicle comprises brake units each including a brake band, or a series of substantially rigid and articulated shoe sections, having located between its ends a cam adapted to be displaced by an electromagnetic device and a fixed abutment serving as an abutment for either end of the band when the other end is displaced by the cam, and a second cam also located between the ends of the band and adapted to be turned by mechanical means to expand the ends of the band. In Fig. 2, which is a section at 2, 2 of Fig. 1, an armature 5 rotates with the brake drum 1 and an electromagnet 6 is normally in light rubbing contact with it. When energized, the magnet moves towards the armature and tends to be carried round thereby, its movement being transmitted by a link 15 to a lever 16, being pivoted at 17, thereby displacing a cam 18 and effecting opening of one of the brake band ends 19, 20 whilst the other is in fixed abutment with a block 22 fixed to the stationary back plate 4. Spring 28 returns the brake band and the magnet to their original positions when the magnet is de-energized. The braking torque may be varied by controlling the current to the electromagnet by means of a rheostat and a resistance, adjustable for different load conditions, which is provided to prevent excessive braking with light loads. A mechanically operated cam 27 is connected by cable to the hand brake lever so that the brake may be operated either mechanically or electrically; simultaneous use of both systems in no way interferring with the full operation of the brake. Two or more rigid shoe sections linked together may be substituted for the single flexible band described.