GB190627717A - Improvements in or connected with Steam and Vacuum Brake Mechanism for Trains and Vehicles. - Google Patents

Abstract

27,717. Gresham, H. E. Dec. 5. Brakes.-In brake systems for trains and vehicles, comprising both a vacuum brake and a steam brake, means are provided for preventing, when desired, the opening of the steam valve for passing steam to the steam-brake cylinders when air is in the train-pipe, as for example when a train is at rest with the vacuum brakes on. In the arrangement shown, the steam valve i is held upon its seat by a lever c which is pressed inwards by the suction of a piston e<1> acted upon by the vacuum in the train-pipe g. Whenever air is admitted to the train-pipe, the steam, acting on the stem i<1> of the steam valve, raises the valve and passes through the pipe i<2> to the steam-brake cylinders. To prevent the valve i from being thus raised when it is desired that the steam brakes shall not be applied while the air brakes are applied, a catch b is put into engagement with a pin h on the lever c ; it is held firmly engaged by the outward pressure of the steam valve on the lever c, but falls away by its own weight whenever vacuum is re-established in the train-pipe g. To ensure positive disengagement of the catch if it fails to fall away, it is pivoted on the rotary air valve a by which the driver admits air to the train-pipe for applying the brakes. Thus, when the valve a is rotated for applying the brakes, it moves away the catch b from the pin h.