GB279718A - Improvements relating to combined steam and vacuum brake control mechanism for railway and like vehicles - Google Patents

Abstract

279,718. Gresham, H. E., and Kiernan, G. April 27, 1927. Fluid-pressure.-Relates to means such as described in Specification 112,549 whereby a steam brake on a locomotive for example may be operated simultaneously with vacuum brakes on the rest of the train while permitting independent hand operation of the steam brake. The apparatus comprises main and pilot steam supply valves d, e operated by an extension of the exhaust valve f the stem g of which is connected to a lever h. This lever is connected to a piston i working in a cylinder the lower part of which is in open connection at j with the vacuum train pipe while the upper part and a reservoir con. nected thereto at k communicates with the trainpipe by a non-return valve m. Thus when the pressure in the train-pipe is increased to apply the train brakes, the piston i is raised thereby closing the exhaust valve f and pipe c and opening first the pilot valve e and then, by a cross-pin e', the main steam supply valve d to admit steam to the locomotive brake cylinder by the pipes a, b. Hand operation of the steam brake is effected by the lever u which acts through a spring v upon a pivoted arm o adapted to engage the lever h. The lever u carries a detent x for engaging a notched quadrant w whereby the lever may be held in adjusted position to determine the degree of steam pressure applied to the brake.