GB320739A - Improvements in and relating to brake apparatus for vehicles - Google Patents

Abstract

320,739. Consolidated Brake & Engineering Co., Ltd., Palmer, B. W., and Cardwell, C. H. Sept. 22, 1928. Fluid-pressure.- In control valve mechanism for vacuum brakes of vehicles of the kind comprising air admission and vacuum lift-valves coupled together and arranged on opposite sides of a diaphragm having an aperture controlled by the air valve, the coupling between the valves is a loose one to ensure a lap position for the valves and the correct seating thereof. The diaphragm is actuated by a pedal &c. through a spring whereby the brake cylinder pressure can be graduated and reacts on the pedal. The valve device comprises a diaphragm 37 dividing the casing 21 into a chamber 36 open to -the atmosphere at 44 and a chamber 35 in constant communication by pipes 22 - - 25 with the brake cylinders 11 - - 14 each connected to one of the vehicle brakes as shown in Fig. 1. A pair of lift-valves 45, 46 loosely coupled by means of a head 54 on the one engaging in a recess in the other are arranged to seat respectively on a collar 41 secured to the diaphragm 37 and on a collar 48 terminating a passage 49 connected by a pipe 26 to the engine suction pipe or other source of vacuum. A cup-shaped member 39 screwed on to the collar 41 carries a tubular part 47 sliding in the casing and open to the atmosphere. A dust-screen 51 for the air entering the member 39 is provided. A spring 32 is arranged between an arm 28 on a rod 4 connected to the pedal 1 and the end of a rod 27 connected to the valve member 47. Normally the valve 45 is held seated by springs 57, 56 and the valve 46 is open to connect the brake cylinders to atmosphere through the tube 47. When the pedal is depressed the diaphragm and the parts attached thereto are moved first to seat the valve 46 and after an interval determined by the loose coupling 54 to lift the valve 45 to connect the brake cylinders to the suction pipe 26 and if the pedal is held the diaphragm is returned against the action of the spring 32 to the lap position in which both valves are seated. The pressure in the cylinders can thus be graduated. This pressure reacts through the diaphragm and the spring 32 on the pedal so that the braking pressure is indicated to the operator. An adjustable stop 62 determines the degree of opening of the valve 45. The rod 4 has a pin-and-slot connection 4<a> with a crank on a rock-shaft 6 connected by rods 8 to the rear brakes which can thus be applied. mechanically by the pedal 1. The brake cylinder chamber 35 of the valve casing may be ported at 52 for a pipe connection leading to an interlocking switch for the vehicle doors the opening of which may thus be controlled through the brake valve. Specification 306,635 is referred to.