GB800196A - Fluid braking systems for vehicles - Google Patents

Abstract

800,196. Cycle brakes. BURGESS, G. N. Aug. 16, 1956 [Feb. 20, 1956], No. 5179/56. Class 136(1) [Also in Group XXXIV] In a fluid pressure or hydraulically operated braking system for vehicles, an operating unit and a slave or power transmitting unit are interconnected so that actuation of the former will result in actuation of the latter to effect operation of a brake unit, the two units each incorporating a flexible sac. As shown in Fig. 1, the operating unit is mounted in a handle bar 10 and comprises a cylindrical plug 11 formed with three portions 12, 13, and 14 of different diameters, the portion 12 being so dimensioned as to be a good sliding fit within the handlebar 10. A flexible sac 15 of non-porous material is clamped in a fluid tight manner over the end portion 14 and constitutes a chamber of variable volume. A piston 18 is slidable in a casing 17 which is fitted over the intermediate portion 13 of the plug. The piston carries a transverse bar having two projections 19 which are connected by rods 20 to a transverse bar 21 which is engaged by the end of an operating lever 22. The plug 11 is provided with grooves within which the rods 20 may slide. A spring 24 is interposed between the projections 19 and a washer 25 which seats against the casing 17. On operation of the lever 22 the plunger 18 displaces fluid from the sac 15 and expels it through a central bore 26 formed in the plug 11 and communicating with passages 27, 28 which receive fittings 29, 30 respectively. The fitting 29 constitutes a bleeder valve device and also serves as a filler device.. The fitting 30 provides a connection for a pipe communicating with a power transmitting unit, Fig. 3. This unit comprises a cylindrical casing 35 into one end of which a plug 36 is introduced. A flexible sac 38 of non- porous material is sealed to the plug 36. The plug has a central bore 39 commmunicating with the interior of the sac. Two radially directed passages 40, 41 extend from the central bore 39. The passage 41 receives the connection 43 to which the pipe from the operating unit is connected. A bleeder valve device 42 is introduced into the passage 40. The plug 36 carries an operating fork member 44 which is adapted to engage one of the brake shoes or operating lever arms of a brake assembly. A floating piston 45 is slidable in the casing 35 and is interposed between the sac 38 and a second operating fork member 50. The axial position of the fork member 50 may be adjusted by means of an internally screw threaded member 41. On displacement of fluid from the operating unit into the sac 38 the piston 45 is displaced to operate the brake. Alternatively, a double acting power transmitting unit having two sacs and two pistons may be used. The operating member may be mounted externally on the frame of the vehicle as shown in Fig. 2. The piston 18 which co-operates with the sac 15 is pivotally connected to an operating lever 31 secured to a shaft 32 carrying a foot pedal or manually operable lever.