GB420900A - Improvements in hydraulically operated brakes for motor vehicles - Google Patents

Abstract

420,900. Hydraulic brakes. CLAMA, A. G., 28, Stockwell Road, Stockwell, London. March 7, 1933, No. 6917. [Class 103 (i)] Means for automatically adjusting the length of a liquid column in a hydraulic brake system to compensate for wear of the friction members comprises a floating piston with. a limited stroke disposed between the master piston and a brake operating piston and having an annular packing which permits passage of liquid from one side of the piston to the other but prevents its return. Fig. 1 shows a brake operating cylinder 4 with a tubular piston 2 for connection at 3 to the cam lever of a brake. The piston has a packing ring 12. A floating piston 1 has a rod 5 extending into the piston 2, a groove 6 being provided to connect the space 30 within the piston 2 with the space 8 between the pistons. The rod 5 may be dispensed with. When in applying the brake, liquid is forced into the end of the cylinder by the connection 7, the liquid between the pistons transmits the movement of the piston 1 to the piston 2 until the piston 1 abuts the stop ring 10, when, if the brake is not applied, liquid flows past the packing ring 11 of the piston 1 so that the piston 2 assumes an advanced position when the brake is released. Fig. 4 shows a pair of pistons 2 actuating brake shoes, arranged in cylinders divided by a partition and formed as a unit with cylinders for floating pistons 1. A simple floating piston may be provided for both of the pistons 2. A unit comprising only two cylinders at right angles, containing respectively a brake operating and a floating piston also is shown. A pair of these may be arranged back to back to give an arrangement similar to that in Fig. 4.