Patent GB-382125-A (GB)
Title: Improvements in or relating to brake apparatus particularly as applied to railway vehicles
IPC: B61H15/00
Filed: 1931-12-24
Abstract: 382,125. Compensating for wear in brakes. GALLUSSER, H., 47, Chemin de Moillebeau, Geneva, Switzerland. Dec. 24, 1931, No. 35687. [Class 103 (i).] A device for automatically taking up excessive slack in brake transmission mechanism comprises a two-part link in the transmission, one part being a toothed rod engaged by a pair of clutch members each disposed in a casing, one casing, forming the other part of the link and the other casing being either fixed or connected to another member of the transmission, the play of the clutch member in this casing determining the normal play in the transmission. Each clutch member comprises a number of segments and has a conical face for engagement with a corresponding face of the casing. The clutch members may instead be arranged on different members of the transmission. As shown in Fig. 1, the twopart link comprises a toothed rod 12 slidable in a part 20 having a casing 2 in which is a conical clutch member 7 comprising a number of toothed segments held by a circumferential spring in engagement with the rod 12. A similar clutch member 6 disposed in a casing 1 has clearance between it and the face 18 of the casing that determines the normal clearance of the brake shoes in relation to the wheels. The clutch member 7 has only sufficient clearance in the casing 2 to permit disengagement from the rod 12. Rotation of the clutch members is prevented by a pin 26 on the casing engaging a slot in the member. The teeth 7 of the rod are preferably formed as a screwthread so that the device may be manually set by turning this rod. As applied to a mechanism comprising a pair of levers 33, 33a, Fig. 5, pivoted respectively to the brake operating piston 32 and to a fixed point, the casing 2 of the two-part link is connected to the lever 33 and the toothed rod 12 to the brakes while the casing 1 is connected by link 38 to the other lever 33a. The lever 33a linked at 33<1> to the lever 33 is connected by rod 41 to another set of brakes. The parts are normally in the position shown and upon an application of the brakes, the casing 2 in moving to the right forces, by the engagement of the conical surfaces, the clutch 7 firmly into engagement with the toothed rod 12 which is thus also moved. The casing 1 is at the same time moved to the left and if by reason of excessive play between the brake shoes and the wheels, the clutch 6 is brought against the face 18 of this casing the toothed rod 12 slips through the clutch causing a corresponding movement of the rod in relation to the clutch 7 during the release movement. In another arrangement, the link 33<1> is the adjustable two-part link, the casing 1 being in this case connected by a link to a lever which is normally substantially parallel to the lever 33 and is pivoted at one end at a fixed point and at the other is linked to the lever 33. A somewhat similar arranement is shown for a vehicle bogie comprising a pair of main levers connected by the adjustable link and each carrying a brake shoe for engaging one of a pair of wheels on one side of the bogie. Fig. 12 shows an arrangement suitable for a motor vehicle in which the adjustable link 86, 87 connects the pedal 85 to a lever 88 on the transverse brake shaft 89. The casings 1, 2 are urged towards each other by a spring 83 and the casing 1 is held stationary by a pair of links 91 freely supported on the shaft 89. The two clutch members need not be arranged on the same transmission member. For example, in Fig. 5, the link 33<1> may be the adjustable link including the parts 2, 7, 12 and each of the pull rods connecting the levers 33, 33a to the brakes may have a toothed part engaged by a clutch member 6 in a fixed casing 1. The device may be modified for links acting in compression.