GB1305497A - - Google Patents

Abstract

1305497 Lifts; control of winding apparatus CLARK EQUIPMENT CO 3 June 1971 [15 June 1970] 18735/71 Headings B8B and B8L [Also in Division F2] An overspeed brake mechanism on a stacker vehicle elevator car 10 movable within frames 12, 14 comprises a generator 18 for providing a speed reference signal of the car, brakes 24, 26 on the car 10 for interacting with the frames and brake actuating means having a pyrotechnic charge electrically detonatable when the speed reference signal exceeds a particular value. Each brake comprises a pair of shoes 32, 34 pivotally mounted on the car and having cam surfaces 48, 58 engageable by a portion 74 of a slide bar 62, which when displaced downwardly due to said detonation causes the shoes to rotate such that serrations 46, 56 thereon engage the frame. A stop 76 on the slide bar 62 maintains the shoes in the disengaged position when the bar 62 is in its inoperative upper position. The slide bar 62 is secured to the wall of a piston spring biased into a brake inoperative position and movable into a brake operative position by the explosive force of a pair of pyrotechnic charges. The bar 62 also operates a switch to de-energize the elevator motion as it moves into its brake operative position. The generator 18 mounted on the car 10 has its rotor 20 drivable by a rack 22 on the frame 12 and a D.C. voltage proportional to the car speed and of polarity according to the direction of car movement, is generated with car movement. The electrical circuitry includes two unidirectionally conductive devices, which allow current flow from the generator to cause de-energization of the elevator rotor upon overspeed of the car 10 in the upward direction and to cause detonation of the pyrotechnic charges upon overspeed of the car 10 in the downward direction.