GB403472A - Improvements in or relating to brake apparatus for railway and other vehicles - Google Patents

Abstract

403,472. Controlling motor vehicles. CONSOLIDATED BRAKE & ENGINEERING CO., Ltd., and PORTER, A. S., Windsor Works, Slough, Buckinghamshire. Aug. 19, 1932, No. 23345. [Class 79 (v).] In a " deadman " device for the compressed air brake system of railway and other vehicles the brake-pipe is vented to effect an application of the brakes only after a predetermined interval following the release of the " deadman's " handle, by a valve which is opened by a spring-urged piston normally held inoperative by compressed air which is exhausted through a restricted passage when the handle is released. The piston may also operate switches to cut off the motor current and to actuate sanding apparatus. Compressed air from the brakepipe 18 is normally supplied through a restricted passage 14, a chamber 15, and a non-return valve 16 to the cylinder 10 so as to depress the piston 11 as shown, against the action of springs 12. A lever 23 pivoted at 24 and passing through a slot in the piston rod 22 is arranged to lift a valve 30 which normally closes a passage 36 to atmosphere. A valve 31 is subject on its upper area to the pressure of a spring and to the brake-pipe pressure in the chamber 15 and to this pressure also on an under annular area so that it is normally seated to cut-off the brake-pipe from the passage 36. A restricted passage controlled by a needle-valve 21 connects the cylinder 10 to the chamber 15 from which also a passage leads to a pilot valve normally held closed by the " deadman's " handle. The lever 23 is connected also to a rod 40 guided by a pair of links 52 and carrying through a spring 51 a floating disc 45 provided with normally closed contacts 41 in the circuit of the vehicle motor. The rod 40 may also carry contacts in the circuit of sanding apparatus. When the pilot valve is opened, the fall of pressure in the chamber 15 enables the brake-pipe pressure acting upon the under area of the valve 31 to lift this valve so connecting the brake-pipe 18 to the valve 30. The compressed air in the cylinder 10 escapes through the passage 20, chamber 15 and the pilot valve, and when the piston 11 rises sufficiently the lever 23 is actuated by a projection 29 on the piston rod, the valve 30 is opened and the brake-pipe exhausts through it to apply the brakes. The contacts 41 are also disengaged to cut-off the power current. The valve 31 is re-closed by its spring when the brake-pipe has exhausted so that when the " deadman " pilot valve is again closed pressure builds up in the train-pipe and the parts return to the normal position. The cylinder 10 may also be exhausted without the delay action to effect the prompt operation of the switch mechanism 40 when the brake-pipe is rapidly vented by a conductor's valve to apply the brakes by the provision of a passage 56 connecting the cylinder to the brake-pipe 18, a non-return valve opening towards the brake-pipe being disposed in the passage.