Patent GB-190227090-A (GB)
Title: Improvements in Apparatus for Working Railway Points and Signals by Electric Power.
Inventor: WEBB FRANCIS WILLIAM
Filed: 1902-12-09
Granted: 1903-06-18
Abstract: 27,090. Webb, F. W., and Thompson, A. M. Dec. 9. Semaphore signals; indicators and repeaters, point or switch and signal; controlling and locking signals.-Relates to improvements in the appa., ratus for working railway points and signals by electric power, described in Specification No. 12,128, A.D. 1897, and consists in arrangements in connection with the check lock, the switch at the points through which the electric current to the signal is passed, and the electric actuation of the signal. The check lock is fitted with two pairs of contact-plates g<4>, p<5>, between either of which may be placed a contact-roller g<3> carried on a crank arm g<2> secured to the end of a rod g<1> provided with tappets g<6>, g<7> at its lower end. When the rod h<1> is moved, the projection h<3> strikes the armature or pole-piece h<7>, the point is moved over, and a current is returned from the points through the switch g<4> to energize the magnet h<4>, which releases the pole-piece h<7> and enables the movement of the rod h<1> to be completed, the projection h<3> then striking the tappet 9<6> and moving the contact-roller g<3> between the plates g<5>. This arrangement prevents a lever from being returned when such lever has been partially pulled over in error, as the magnet for releasing the armature or pole-piece does not become energized. Fig. 1 shows an electric switch for establishing the circuit by which a current to the signal is carried. A lever a<3>, kept up to a plunger a' by a spring a<4>, carries an insulated contact a<5> for making contact between two tongues a<8> having terminals a<9>. An electric switch is placed at each side of the points. When the switch is operated, a very slight movement of the point tongnes a opens both electric switches, and leaves them open until the tongue a nearly touches the stock rail a<1>, when it strikes the bolt a' and forces the contact-piece a<5> between the tongues a<8>. Figs. 4 and 7 show a check lock applied to a signal lever to prevent it from being put back in case the signal arm has not responded to the movement of the lever and risen to the " danger" position. When the lever is pulled over to transmit a current to the signal, the rod e<3> is moved, and blocks a, b complete a circuit from the battery g through a magnet W to pull down the signal arm ; the switches c<1>, c<3> are opened, and the current returns through the resistance R. The movement of the rod e<3> also brings the projection p<1> past the armature or pole-piece s<1> of the magnet m<1>. When the rod e<3> is returned, the circuit through the magnet W is broken, and, when the signal arm rises to the "danger" position, the circuit through the magnet m<1> is completed, which raises the armature s' and allows the movement of the rod e<3> to be completed. If the signal fails to respond to the return movement of the lever, the switches c<1>, c<3> remain open and prevent the completion of the current which energizes the magnet m<1>; the armatures' consequently prevents the return of the rod e<3> by engaging the projection p<1>.