GB555133A - Improvements in and relating to fluid operated clutches or coupling devices - Google Patents

Abstract

555,133. Disc brakes. SELF-CHANGING GEAR CO., Ltd., WILSON, A. G., and MILLER, A. A. Feb. 2, 1942, No. 1357. [Class 103 (i)] [Also in Group XXIV] In a friction coupling or brake the friction surfaces are first brought into light driving and sealing contact by pressure fluid concentrated over a small area between the friction parts and near the centre of rotation after which the pressure is extended over the large area between the friction parts to produce the full engaging pressure. As shown, a clutch member b on an input shaft d has a small annular cylinder g into which fits a piston h on a clutch member a. Pressure fluid supplied through ducts e, f, to the cylinder g moves the member b against the pressure of a spring t to cause initial light engagement of the cone clutch faces. The fluid pressure also passes by means of a groove k to act on a double piston valve member l, o, p. The latter thereupon moves against the pressure of a spring r to uncover a pressure fluid inlet port m to the main pressure chamber n and to close an outlet duct q. The fluid pressure in the chamber n supplies the main clutch engagement pressure. For disengagement the small chamber k is open to exhaust whereupon the piston valve moves to close port m and open duct q. The fluid in the chamber n is evacuated through the ducts P, u, and the friction faces are separated by the spring t. The piston valve member may be conter-balanced or disposed axially of the clutch. The Figures shows a pair of cone clutches arranged back to back. In a modification, particularly for low speed clutches or brakes the piston valve is omitted, the rate of entry of pressure fluid into the main pressure cylinder being restricted by an adjustable choke pin.