GB561244A - Improvements in or relating to the braking of vehicles - Google Patents

Abstract

561,244. Hydraulic brake systems. ARMANDIAS, L. S., and ASSOCIATEID MESSIER INVESTMENTS, Ltd. Nov. 5, 1942, No. 15640. [Class 103 (i)] A.hydraulic brake comprises a hollow friction element movable to engage a relatively rotatable friction element by hydraulic pressure and through which the pressure liquid circulates so as also to cool the hollow friction element. The system shown comprises a master cylinder arranged to operate a valve to throttle the flow of liquid circulated by a pump and thus to build-up pressure in the hollow friction element. In Fig. 1, hollow friction elements 11, 12 of, for example, stainless steel, are attached to a diaphragm 6 apertured at 27 and mounted on the axle 2 of a vehicle wheel 1 and are arranged to engage friction elements 13, 15 of a material of relatively low heat conductivity secured to discs 16, 17 of the wheel body. Pipes 18, 25 lead from the elements 11, 12 respectively to a pump 19 and to a regulator 31 which comprises a needle valve 37 carried by a piston 38 adapted to be moved against the action of a spring 39 to cause the valve 37 to enter an orifice 36 in a partition 42 within the casing 32. A collar 40 is slidable on the valve 37 against the action of a spring 41 which bears also on the piston. An accumulator 20 comprises a piston 22. dividing a compressed air chamber 24 from a chamber 23 connected to pipe 18. The piston 38 is operated by a master cylinder, the piston 49 of which carries a valve 54 normally unseated to establish communication between the reservoir 28 and pipe 46 through the annular chamber 50 and passage 52. Initial movement of the pedal 59 causes the valve 54 to close and also by connections not shown, engages a clutch whereby the pump 19 is driven by the driving motor of the vehicle so that liquid is circulated from the' reservoir 28 through pipe 18, the friction elements 11, 12, pipe 25, the orifice 36 and back to the reservoir. Upon further movement of the master piston 49, the needle 37 is moved by the piston 38 to throttle the orifice 36, whereby pressure builds up-in the elements 11, 12 to apply the brake and also in the accumulator 20, the liquid and thus the brake being cooled by a radiator 26. Upon sufficient increase of the pressure applied to the piston 38 by the master cylinder, the collar 40 seats on the partition 42 and the brake may thus be held applied when the'vehicle has been stopped, by reason of the position of a non-return valve 61. In a modification, Fig. 2, the pump 62 is driven by a gear-wheel 64 which is engaged with a crown wheel '63 on the wheel 1 by the initial movement of the pedal by connections not shown. The pipes 65, 66 which connect the pump to the friction elements 11, 12, the regulator and the reservoir 28 are arranged as shown. A brake is also shown in which the friction elements comprise a pair of annular pistons in cylinders arranged one on each side of the wheel coaxial with the axle, the inlet and outlet pipes and baffles being so disposed as to cause the liquid to circulate circumferentially in the cylinders.