Patent GB-1000969-A (GB)
Title: Brakes and clutches displaceable by means of pressure medium
IPC: F16D65/18
Filed: 1961-11-22
Abstract: 1,000,969. Brakes; friction and ratchet clutches. ALLMANNA SVENSKA ELEKTRISKA A.B. Nov. 22, 1961 [Nov. 23, 1960], No. 41729/61. Headings F2C and F2E. A brake or clutch device comprises a member movable in relation to another and frictionally engageable therewith under the influence of a continuously acting brake or clutch force and means to deliver a continuous flow of pressure medium to the surfaces forming the division between the members for separating the latter. As shown in Fig. 1, a plate a provided with friction material b is loaded with a force F which presses it against a braking disc c. In order to lift the plate a from the disc c a pressure medium is supplied through a duct e to a chamber f from which the pressure medium flows out through the space h. A mechanical guide in the form of a through running shaft may be provided between the members a and c. In a modification, the chamber f is annular and the plate a may be provided with a central opening. In another modification, the diameter of the friction material b is somewhat larger than the diameter of the brake disc. With wear an edge is formed on the friction material which acts as a seal. In a further modification the brake disc c is provided with a number of concentric grooves which forms a seal as described above. In another embodiment, Fig. 4, the plate a is constructed so that pressure medium is supplied to three chambers f through throttled inlets. The chambers may be arcuate. In a further embodiment a separate ring acting as a seal is provided around the plate a and is provided with frictional material which is pressed against the brake disc c by either the pressure medium or springs. In yet a further embodiment of brake, Fig. 9, the plates a with linings b are pressed by springs l against the brake disc c and pressure medium is supplied to chambers f. The plates a are attached to rubber membranes m which have a number of bushings n slidable on shafts o. A bellows may be provided between the membranes m to act as a seal at the periphery of the disc. Internal and external shoe-drum brakes and spot-type disc brakes are described wherein the brake is released by pressure medium between the braking surfaces. The gap between the members is kept very small and the flow of the pressure medium over the friction surfaces effects cooling of the surfaces where any friction occurs in the disengaged position. The gap is also substantially uneffected by wear of the friction surfaces. In an embodiment of clutch, Fig. 15, the spring-loaded plate a is disengaged from the plate c on supply of pressure fluid through duct e and duct x in the rotating shaft u. The duct x may be provided with a centrifugal speed control valve to effect a smooth engagement of plates a, c. In another embodiment of clutch, Fig. 16a, a hub z is rigidly connected to the shaft u and drives the disc a by means of a claw connection which has great clearance. By turning the hub z in relation to the disc a the connection is opened or closed between the ducts x, y so that free coupling is obtained in one direction of rotation and engagement in the other.