GB268296A - Improvements in brake mechanism - Google Patents

Abstract

268,296. Waygood-Otis, Ltd., (Assignees of Jones, B. N.). March 23, 1926, [Convention date]. Applied by springs and weights; block and the like acting on drums; force-transmitting mechanism; electric.-Relates to brakes, comprising friction shoes engaging a drum more particularly multiple-shoe braking mechanism for lifts and the like wherein the shoes are automatically applied by mechanical means and released by an electric or other rotary motor during hoisting. The Brake is released by one or more cams 48, 68 on the releasing motor shaft 47, which is allowed axial travel to balance the movements of the brake shoes. The cams 48, 68 are face cams and engage rollers on the end of pivoted levers 56 connected by adjustable links 67 to levers 36 pivoted on pins 42 carried by the brake frame. The levers 36 carry the brake shoes 35 in openings in the levers on pins 37. Brake applying springs 38 are mounted between a spring seat 27 mounted on the pin 37 and an adjustable spring seat 31 carried by the brake frame. When the motor is energized the cams 48, 68 are rotated to release the brakes a pinion 73 on the motor shaft lifts a dash-pot piston 87 by means of a rack 81 until a buffer spring 88 engages the dashpot cylinder cover and the motor is stopped but maintains the brakes applied as long as it is erergized. On de-energization of the motor the piston drops rotating the motor shaft and allowing the springs 38 to apply the brake shoes. If on releasing the brake one cam engages before the other the motor shaft slides to cause the other cam to engage and both brakes are released simultaneously. If in applying the brake one shoe engages before the other the operating cam thereof recedes from its roller and allows the pressure of the application spring of the other brake to cause the motor shaft to slide and apply this other brake. Brake release stops 105, 108 are provided on the brake levers 36 and engage the brake casing. If one application spring is stronger than the other the motor axle slides and the cam releases the brake with the weaker spring. 'When the stop 105 or 108 engages, the axle slides back again to release the other brake. Considerable clearance is allowed for the motor axle bearings 51, 71 between covers 111 and housing hubs 112. to allow the axial movement. The flow of air into and out of the cylinder 82 of the dash pot piston 87 is controlled by a replaceable ball check valve 90 and a passage 92 fitted with a longitudinally slotted adjusting- screw 93. The brake shoes are maintained concentric with the drum by adjustable springs 100, mounted on the levers 36, which holds the shoe in engagement with adjustable stop 96, also mounted on the lever 36. The upper ends of the levers 56 are in the form of yokes to clear the cams. The whole motor may slide axially.