GB489606A - Improvements in or relating to friction clutches and brakes - Google Patents

Abstract

489,606. Friction clutches combined with brakes. SCHULER AKT.-GES., L. Feb. 24, 1938, No. 5907. Convention date, Feb. 24, 1937. [Class 80 (ii)] The clutch of a combined friction clutch and brake in which the plates rotating with the driven shaft upon which the clutch and brake engaging forces act directly are connected together rigidly is engaged by air pressure and disengaged by spring action, the force of the spring being only sufficient to disengage the clutch, whereas the brake is engaged by continuously acting air of lower pressure than the air for operating the clutch. In one arrangement, an annular chamber 19 or a number of cylinders 18 are located between the clutch 6 and the brake 4 and rotate with the shaft. Working in the annular chamber or each cylinder is a spring pressed piston 21 or 20 secured to a rod 24 or 22 which rigidly connects the presser plates 14 and 10 of the clutch and brake respectively. Pressure air for engaging the clutch is admitted to the spaces 26 in the chamber or cylinders through a conduit 29, an air vessel 31, a three-way valve 32 and bores 33, 34 when the three-way valve is set in the appropriate position. Air of reduced pressure is supplied to the spaces 27 of the chamber or cylinders from the air vessel 31 through a reducing valve 35, an equalizing vessel 36 and bores 38, 39. This reduced pressure air acts continuously so that when the three-way valve releases the air in the spaces 26 the springs 28 disengage the clutch and the air in spaces 27 operates the brake. In a modification an externally located pressure air cylinder operates the clutch and brake by means of a piston rod passing axially through the shaft and connected by a linkage held in a hub of the shaft to the rod of the clutch and brake presser plates. The externally located cylinder is controlled by a three-way valve in a similar manner to the cylinders of the first described arrangement.