GB648368A - Improvements in or relating to control devices for compressed air brake systems - Google Patents

Abstract

648,368. Fluid pressure brakes. ATELIERS DES CHARMILLES SOC. ANON. Aug. 10, 1948, No. 21073. Addition to 605,781.. [Class 103 (i)] In a fluid pressure brake system, particularly for railways, of the type described in the parent Specification comprising a brake pipe, H, h, a regulating or triple valve RV, a quick inshot valve M, brake cylinder BZ, changeover locks U, auxiliary reservoir L, control reservoir S and accelerator unit B, there is also provided an equalizing valve unit AV, the purpose of which is to prevent communication between the reservoirs S and L being established during a release operation, before the pressure in the auxiliary reservoir L reaches nearly its normal value. Whereas in the parent Specification, this is brought about by brake pipe pressure acting in chamber 6, below the lower movable part of the valve unit AV, thereby exercising a controlling influence on the opening of valve 33, in the present invention the brake cylinder pressure is made to operate in the chamber 6. The movement of the valve member 2 to open the valve 33 depends on the upward force due to the brake cylinder pressure in chamber 6 and control reservoir pressure in chamber 7 opposed to the downward force exerted by the auxiliary reservoir pressure acting in chamber 9 and by spring 21 which is of such a strength that the valve 33 is not opened until the brake cylinder pressure has decreased below 0.4 kg./cm<SP>2</SP>.