Patent GB-386023-A (GB)
Title: Improvements in automatic train signals for level crossings
IPC: B61L29/28
Filed: 1931-08-19
Abstract: 386,023. Train-actuated signals. RICCARDI, A., 553, Via Tuscolana, Rome, and SOC. ANON. BREVETTI ITALIANI ESTERI (S.A.B.I.E.), 2, Via Lamberti, Florence, both in Italy. Aug. 19, 1931, No. 23325. Drawings to Specification. [Class 105.] A level-crossing signal is actuated by a weight motor wound up by rail deflection on the passage of the train and the initiation of the signal is effected by a track contact. The rail deflection effects the winding up of the weight motor by reciprocating a rod linked to a ratchet drive for a cable drum whereby the weight is lifted. When the drum unwinds it drives a gear train through a reversely arranged ratchet but the winding-up ratchet must first be withdrawn ; this is effected by rocking a cam to disengage the pawls. An approaching train repeatedly actuates a magneto-generator by a rail-deflection-operated hooked rod to energize a magnet whereby a weighted lever is allowed to fall and so starts the signalling operation. Alternatively the rail deflection may open a contact to de-energize a magnet whereby the weighted lever is allowed to fall. The fall of the lever effects, through linkage, the disengagement of the winding-up pawl and removes a detent from the gear train which thereupon drives a mechanical hammer to sound a bell and a crank to oscillate a warning semaphore arm which carries a flashing light supplied from a generator and switch also driven by the gear train ; the crank is driven through a yielding clutch. When the train reaches the level crossing the weighted lever is restored by a tappet lever operated by the winding-up mechanism. To prevent overwinding, the drum carries a tooth to operate a star wheel a pin on which eventually moves a lever to rock the cam by which the winding- up pawl is disengaged. If the apparatus should fail and the weight descend beyond a certain point the weight then removes a detent from a tensioned wire and so releases a weighted emergency signal arm for exposure to denote " apparatus out of order." A single apparatus is used for traffic in either direction with single or double tracks. With double tracks each track has a corresponding weighted lever either of which on falling will operate a forked member to start the signalling operation. Likewise each track has a reciprocating rod for the winding-up operation, either of which, by means of bell cranks with lateral extensions, will pull down the rod connected to the winding- up mechanism. With single tracks, that initiating track contact which is passed after the level crossing is reached must be made ineffective to give a signal ; this may be achieved by a subsidiary gear train, wound up by the main gear train operation, which subsidiary gear train is fitted with a pendulum escapement so that a rod, raised into position to prevent the movement of the magnet armature when the second initiation impulse is received, is only withdrawn after a determined time interval. Alternatively electromechanical means may be used comprising a subsidiary weighted lever which is raised by the fall of the first weighted lever and retained by a magnet armature and is only released to restore the circuit of the signal starting magnet when the receding train operates the other initiating track contact.