GB345079A - Improvements in or relating to single chamber compressed air brakes - Google Patents

Abstract

345,079. Fluid-pressure brakes. HILDEBRAND, W., 3, Ulmenplatz, Lichterfelde, Berlin. March 10, 1930, No. 7767. Convention date, March 11, 1929. [Class 103 (i).] In a single chamber compressed air brake in which the release of the brake can be effected in successive stages the filling of the constant pressure control chamber is regulated by a slide valve controlling the release of the brake, this valve comprising a piston Ka is exposed to the pressure in the train pipe L (or in the auxiliary reservoir) and on the other side to the pressure in the control chamber A, so that on brake operation the valve S quickly shuts off the connection a<1> between the control chamber and the train pipe (or auxiliary reservoir) in which a reduction of pressure is taking place whereby return flow of the control chamber contents is prevented and a clearance is provided between the slide valve piston and a piston Kc exposed to the pressure in the brake cylinder C whereby the effect of the latter on the valve ceases before the inlet to the control chamber is again opened and this inlet remains closed till the train pipe or auxiliary reservoir has attained its maximum value. In release position the brake cylinder is connected to the exhaust outlet o, and when the valve moves up on brake application the brake cylinder is connected to the auxiliary reservoir B and the rod of the piston Ka raises the piston Kc. The increased train pipe pressure on brake release and brake cylinder pressure move the valve down connecting the brake cylinder by a small branch c<1> to exhaust, and the valve comes to rest, owing to the fall in brake cylinder pressure, before the inlet a<1> is exposed. The braking action is thus reduced step by step.