Patent GB-580369-A (GB)
Title: Improvements relating to braking apparatus for electrically propelled railway or like vehicles
IPC: B60T13/66
Filed: 1944-01-03
Abstract: 580,369. Fluid-pressure brakes. WESTING- HOUSE BRAKE & SIGNAL CO., Ltd., SIMMONS, A. W., and KERSHAW, J. W. G. Jan. 3, 1944, Nos. 49/44 and 1008/45. [Class 103. (i)] [Also in Group XXXVII] In fluid-pressure operated brake mechanism for vehicles, adapted to exert what is termed a normal braking action and wherein means are provided for augmenting or varying this action in accordance with the speed and which is interlocked with a second brake mechanism, for instance, an electric regenerative or rheostatic brake, the interlocking is arranged to reduce or cut out only the normal braking action, the additional speed controlled action remaining unaffected. As shown in Fig. 1, a normal brake cylinder 1 is supplied from a drivers brake valve or a triple valve by pipe 8 and an interlock valve 3 controlled by an electric regenerative brake acting through a coil 12. An auxiliary brake cylinder 2 is supplied through a pipe 5 from a source the pressure of which is dependent upon the speed of the vehicle. The supply to the cylinder 2 is controlled by the pressure in the pipe 8 acting through a relay valve 4, the pipe 8 being connected to the chamber 18 between pistons 17 which respectively operate supply and exhaust valves 14, 15. Normally the cylinder 2 is exhausted through the valve 15 and the cylinder 1 through valve 9 and pipe 8. When the brakes are applied pressure fluid is supplied to the cylinder 1 through the pipe 8 and valve 9 and to the cylinder 2 through the pipe 5 and valve 14. As the speed is reduced the pressure supply in the pipe 5 and cylinder 2 is correspondingly reduced. If regenerative braking is effected, the valve 9 is closed .and valve 11 is opened thus exhausting the cylinder 1. According to Fig. 2, a single cylinder 19 is used and is supplied from a reservoir through a pipe 33 under the control of a booster valve device 20 comprising pistons 25, 26, 22 operating supply and exhaust valves 32, 31 and subject respectively to the pressure in the cylinder 19, that supplied to the pipe 8 when the regenerative brake is inoperative and that supplied from the pipe 5 through the relay valve 4. The chambers of valve 20 above the pistons 22, 26 are open to atmosphere. When the brake is applied with the regenerative brake inoperative pressure fluid is supplied from the pipe 8 through the interlock valve 3 to the chamber beneath the piston 26 and from the pipe 5 through the relay valve 4 to the chamber beneath the piston 22. The valve 32 is thus opened to supply the cylinder 19 until the pressure therein acting above the piston 25 is sufficient to overcome the pressures acting beneath the pistons 22, 26, the pressure beneath piston 22 being dependent upon the speed. If the regenerative brake is operative, the valve 11 is opened to exhaust the chamber beneath the piston 26 and the pressure established in the cylinder 19 is due only to that supplied from the pipe 5 to the chamber beneath the piston 22. The interlock valve device instead of acting to cutout part of the action of the fluid-pressure brake may act to vary that part in inverse proportion to the action of the regenerative brake, the valve being, for instance, such as described in Specification 348,578.