Apparatus for Operating Railway Signals, Train Stops, Train Brakes and Crossing Gates

24,261. Johnson, A. H. Nov. 12. Brakes-Relates to means for operating railway signals, train brakes, &c. and consists in improvements in connexion with the apparatus described in Specification No. 11,005, A.D. 1905, [Abridgment Class Railway signals &c.]. The signals &c. are operated from an electric motor m in a casing j, which motor drives a Roots' blower or similar type of rotary pump enclosed in an inner casing r, to pump oil, which fills the casing to the level h-h past the non-return valve d into a chamber V . The oil passes through the duct f to the cylinder c, thus lifting the piston p, to which is attached the operating-rod p for the signal &c. to be moved. A partly balanced gate-valve V pivoted at z is held closed by the armature n of an electro-magnet o in parallel with the motor, but, when the motor circuit is broken at the main switch, the valve is opened by the pressure of oil under the piston p, which is thus allowed to drop quickly. The motor circuit is alone broken, however, when the switch s is opened on the completion of the necessary movement of the operating-rod p , at which time a pawl t mounted on a pivoted lever y, which normally holds the contact s' up to close the circuit, is forced over by the spring w acting on the roller w to open the switch quickly, the movement being allowed by the driver u, which normally holds the switch closed, moving above the pawl. On the return of the member p after the motor circuit is broken, the pawl is first forced out by the lower end of the driver u without moving the lever y, as shown in Fig. 4 ; but, as soon as the corner formed by surfaces t , t is passed, the spring quickly snaps the pawl up to its normal position and closes the switch s. To prevent the signal &c. from sticking in its operated position, a constant leakage is allowed past the piston p, or a leak port is provided therein, whereby a constant movement is given to the member p , which first drops with leakage until the switch s is closed, whereupon the motor m pumps more oil until the switch again opens. Should the valve V fail to open when the main switch is opened, this leakage allows a gradual return of the operated member. To prevent the raising of the piston by means, other than by pressure of oil, a detent x is pivoted to the rod p and normally engages in a recess x in the casing, from which recess it is moved by air pressure on the plug x . Instead of the piston, a diaphragm, ram, or equivalent device may be used, and the ac