GB1132022A - Distributor valve device for pneumatic brakes - Google Patents

Abstract

1,132,022. Fluid-pressure brakes. OERLIKON-BUHRLE HOLDING A.G. 6 Jan., 1966 [7 Jan., 1965], No. 649/66. Heading F2F. A triple pressure or other distributer valve for compressed-air rail vehicle brakes, of the kind which includes an accelerator valve 9 which is lifted off its seat by movement of the piston 3 responsive to brake pipe pressure, when a reduction of pressure in the brake pipe 1 occurs, via a thrust member 4 and a lever 5 pivoted to the member 4 which, either by engagement of its spring-loaded arm 7 with casing partition wall 21 or by being struck by piston rod 11 of a piston 14 responsive to rise of pressure in the brake cylinder 54 as a result of opening of the inlet valve 32 communicating the cylinder with auxiliary reservoir 55, is caused to disengage from depending stem 8 of the accelerator valve 9 after a sufficient reduction of pressure in control chamber 19 has occurred through expansion into transfer chamber 12, is characterised in that either the piston 14 or, as shown, a second piston 25 is acted on also by the pressure in the transfer cnamber so that pivoting of the lever 5 to a disarmed position is ensured even if pressure rise in the brake cylinder is unduly delayed. In the embodiment shown, brake cylinder pressure acts on piston 14 by way of a line 13 communicating with a chamber 47 between the pistons 25 and 14, and pressure in the transfer chamber 12 is communicated by line 46 to a chamber 43 behind piston 25, a bleed 39 providing for exhausting of the transfer chamber when the brake is released. The inlet valve 32 is integral with an exhaust valve 30 co-operating with a seat 26 communicating via passage 24 in a reaction piston 15 with an atmosphere-connected chamber 23. In the embodiment of Fig. 2 (not shown), the distributer valve is identical excepting that piston 25 is omitted and, instead, a shuttle valve 61 is subjected at its ends to the pressures in the brake cylinder and transfer chamber, respectively, whereby whichever of the two pressures is the highest is communicated via a line 59 to a chamber 60 behind piston 14. In this embodiment the transfer chamber is bled by a bleed hole 57 in the wall of the transfer chamber itself.