GB890612A - Improvements in or relating to winding engine brake arrangements operated by pressure medium - Google Patents

Abstract

890,612. Winding engine brakes. SIEMENSSCHUCKERTWERKE A.G. July 28, 1958 [July 26, 1957], No. 24256/58. Class 103 (1). A pressure-medium-actuated winding engine brake has a working circuit including a service brake piston and cylinder 1, 45, and a safety brake piston and cylinder 2, 46, is directly connected to pressure source 22, and has a control circuit including a pressure reservoir 26 and pressure setting members for controlling pressure in the working circuit, and being connected via an adjustable throttle 19 to source 22. With the emergency lever 13 as shown, compressed fluid is supplied from pipe 15 to valve 14 and via electromagnetically-controlled valve 6 to act on diaphragm 44 in valve 8 which is opened to supply compressed air to cylinder 2 from pipe 37 via pipes 25, 24. Rotation of service lever 11 towards the shown position opens valve 40 to supply compressed fluid to valve 5 until valve 12 returns to a lap position; pressure in chamber 20 of valve 5 moves diaphragm 48 to open valve 30 and supply compressed fluid to cylinder 1 via pipes 38, 23, the valve 5 moving to a lap position. For emergency braking, lever 13 opens contacts 56 to de-energize valve 6 to exhaust pressure from valve 8 via member 59 and port 71; the stem 64 in valve 8 rises to vent cylinder 2 via throttle 9 and weight 3 lowers piston 46 to apply the brakes. Valve 74 is raised by cam 72 to disconnect pipes 18 and 27 and vents pipe 18. Movement of safety lever 13 to close contacts 55 re-energizes valve 6 for recharging of cylinder 2; contacts 62 then being closed by pressure valve 7 and lever 13 is returned to its neutral position. Throttle 19 and reservoir 26 are such that with normal frequency of control operations the pressure does not drop to more than a pre-determined extent; however, on unexpected consumption of fluid downstream of throttle 19 the pre-determined drop is exceeded and pressure valve 7 opens its contact to de-energize valve 6 to apply the safety brake. Specification 226,547 is referred to.