Fluid pressure actuator with a spring-intervention device for the brakes of railway vehicles and the like.

摘要

An actuator for railway vehicle brakes comprises a casing (12) defining a cylinder (68) in which is slidable, under the effect of fluid under pressure, a piston (32) driving a rod member (22) displaceable axially through one end of the casing to actuate brake means. The actuator is provided with spring-intervention means (90, 92, 100, 106) for effecting the advancement of the rod member (22) to achieve parking or emergency braking automatically. The spring-intervention means are interposed between the cylinder (68) in which the piston (32) is slidable and the end (16) of the casing (12) through which the rod member (22) passes, and cooperates directly with the rod member. Manually-operable releasing means (80, 108) are provided which, in the activated condition of the spring-intervention means, withdraw the rod member (22) by means of a device for taking up the play (42, 46) with which the latter is provided.