Patent GB-704767-A (GB)
Title: An improved non-token machine for the control of trains and like vehicles between stations
IPC: B61L23/12
Filed: 1950-10-13
Abstract: 704,767. Railway signalling systems. SCHOOR, M. C. VAN. Oct. 13, 1950 [Oct. 14, 1949 ; Dec. 9, 1949 ; June 3, 1950], No. 25082/50. Class 105 In apparatus for controlling traffic over a single line in either direction between two stations or for releasing an occupation token for a working party, in which each station is provided with an instrument comprising a polarized magnet energizable from the far station to lift a locking pawl and allow rotation of a commutator in the line wire circuit when a normal current is received and thereby allow a starting signal to be cleared or the occupation token released the apparatus being restorable to normal only when the train reaches the far station or the occupation token is replaced, the apparatus is made such that before the starting signal can be cleared the commutator after release by a normal current from the far station must be operated to reverse position by manual means which cause the completion of a first circuit which closes a point in a second circuit by which a lock on the starting signal lever is removed the arrival of the train at the far station causing at such far station the reversal of an auxiliary commutator by which a current can be sent which at the departure station becomes of normal polarity and .allows the instrument at -the departure station to be restored to normal; the occupation token can be removed without any further action (from the far-station) after the signal has been cleared and restored to danger on the departure of the through train but otherwise it can only be removed by receipt of a normal current from the far station. The apparatus is a modification of the apparatus described in Specifications 517,051 and 592,712 to avoid the use cf tokens for the through traffic. Fig. 1 shows a front view and Fig. 4 a rear view of an instrument, Fig. 6, showing a part thereof on an enlarged scale. Figs. 8, 9 show an arrangement by which there can be obtained an occupation token for a working gang or for shunting. Figs. 11, 12 13 show mechanical details relating to the return to normal after the departing train has passed over the short track circuit at the far end. Fig. 14 shows the circuit arrangement between the instruments at the two ends of the block length. The instrument comprises a rotatable drum 5 with connecting segments 89 thereon to cooperate with conducting fingers 110 and form a reversing switch LC for the line circuit, L<SP>1</SP>, L<SP>2</SP>, Fig. 14. The drum 5 has an.extension 12 in which is housed a member 16, Fig. 6, longitudinally slidable in a transverse passage 17 therein such member carrying a contact strip 26 and a pivoted contact 27 which co-operate with conducting fingers 23, 24, 25 connected to windings P, Q, Fig. 14 of a relay SR which thereby sets its contact to one or other point, X, Y whereby at point X a circuit is prepared in readiness to clear the starting signal lever lock when the operator depresses a footswitch FS. If the contact is on-point Y a circuit is prepared to a magnet SLC by which a token key ;for shunting or for working gang occupation can be released. There is an auxiliary drum commutator 31, Fig. 4, the movement of which to its reverse setting is effected by a torsion spring 39 when an escapement armature 40/53 controlled by a magnet BCC is first energized and then de-energized. The magnet BCC of the far station is energized when the departing train closes a short-length track circuit at the far end formed by two short separated insulated rail lengths 100 which are spaced apart nearly the length of the.wheel base of a vehicle. The armature 40 of the magnet BCC serves as an escapement for a pin 51 extending from the shaft 30 of the drum 31 of the auxiliary commutator, the end of the armature 40 having a horizontal extension 53 notched as shown in Fig. 11 ; the escapement under the action of the torsion spring 39 is only partial until the train has completely passed whereupon the armature falls back to allow the torsion spring 39 to remove the pin 51 completely from the notch. To return this auxiliary drum commutator 31 to normal a normal;line current must be received from.the entrance end to retract the.polarized armature of a blocking dog 57 to permit a handle 43 to be pushed in axially for engagement of clutch dogs 44, 45, Fig. 12. For a train to travel from station A to station B, Fig. 14, bell signals are given over the line wire circuit L<SP>1</SP>, L<SP>2</SP> by depressing a sending key SS to send current, the line wire circuit.including at each station the main commutator LC (5) at normal, a needle indicator G, a receiving press key RS, a sending press key, SS, a winding of a polarized line indicator L<SP>1</SP>, a winding BCP of the polarized armature 59 of the blocking. dog 57 and a bell winding BC. The operator at B then depresses his sending key SS<SP>1</SP> to apply normal current from positive battery to line L<SP>1</SP> over auxiliary commutator BRS<SP>1</SP> (31) at normal and commutator LC<SP>1</SP> (5) at normal. At station A this normal current passes over commutator LC at normal and depressed key RS to the winding PLC of the polarized locking pawl in the sense to lift the pawl to allow the operator at A by pushing in a handle 18 and turning it (90 degrees or 180 degrees) to reverse his commutator LC (5) and to close first the contact 23/24 by the pivoted piece 27 and strip 26 and later (on allowing the handle 18 to move back axially by its spring 15) to close the contact. 24/25. The contacts 24, 25 prepare a circuit for a local battery LB to energize, by the operator pressing on a foot contact FS, a winding TLC to free the starting signal lever at A ; this circuit includes the armature of the relay SR being on its contact X, the armature of this relay having been set to this position by its winding P having beeri energized over the contact 23/24. When the train reaches station.B the track circuit winding TR<SP>1</SP> closes the contact M<SP>1</SP> N' whereby a battery LLB<SP>1</SP> energizes the winding BCC<SP>1</SP> of the escapement armature for the auxiliary drum commutator BRS<SP>1</SP>. This circuit includes contacts HS' (home signal for B at clear) and a contact SW2<SP>1</SP> (the auxiliary commutator BRS<SP>1</SP> (31) at normal). The further commutator BBS<SP>1</SP> (31) thereupon moves to its reverse setting by the action of the torsion spring 39. Bell signals are now exchanged and the operator at B thereupon applies reverse current to the line wire circuit L<SP>1</SP> L<SP>2</SP>-but at station A with the commutator LC (5) still at reverse a normal current flows in the instrument at A which lifts the appropriate locking pawl to allow the commutator at A to be returned to normal. The operator at A now sends normal current whereby the polarized armature of the blocking dog 57 moves to allow, the handle 43 of the further commutator BRS<SP>1</SP> to be pushed in to engage the dogs 44, 45, and to be turned to return the auxiliary commutator. BRS<SP>1</SP> to normal. All instruments are now again normal. To allow shunting movements at A a token 70 carried in a barrel 71 interlocked with the commutator shaft 12 must be extracted ; this requires that B send a normal current to allow the commutator at A to be turned (90 degrees or 180 degrees) thereby freeing the barrel 71 so that it can be turned and the token 70 extracted. The commutator at A is now locked by the tappet 75, Fig. 9. If the commutator has only been turned 90 degrees it can be returned to normal as soon as the token has been re-inserted in the barrel 71 and the latter turned to allow the tappet 75 to move on to the "flat" 72. This is because the locking disc 6 of the commutator is not shouldered at the 90 degrees position. The movement to the 180 degrees position (to close contacts 23, 24, 25 to allow the starting signal at A to be cleared) requires that the operator shall pull out a, pin 80, Fig. 6, from engagement with a limiting groove 81 in the handle 18. The freeing of the barrel 71 requires that an armature 7 7 be removed from blocking position in a notch 98 ; the magnet SLC for this is energized (when the operator closes a contact Z) over the armature of the relay SR on contact Y the position in which it is normally left. If however the commutator had been turned 180 degrees for a train to travel to B the token release magnet SLC cannot be energized till the starting signal lever at A (operated to clear the signal for such train) has been returned to put the starting signal back to danger and by closing a contact TS just before the signal lever reached the full normal position has energized the winding Q of the relay SR to put the armature on contact Y, such armature having been put to the X contact when the commutator handle 18 was pushed in and turned 180 degrees preparatory to the clearing of the starting signal. Thus the shunting token cannot be obtained until the prior through train has gone beyond the starting signal and the signal lever therefor has been returned to normal. To ensure that the locking pawls engage the locking disc 6 there are provided cams 132 on a shaft 135 which at its outer end has a lug 136 depending into a groove 22 on the handle piece 18. Thus, before the handle 18 can be pushed in, the shaft 135 must be turned to remove the lug 136 from the groove 22 and so by the cams 132 pressing down the locking pawls ensure that these engage the disc 6. 'When the handle 18 is pushed in then the lug 136 drops back into a second groove 21 so that after turning the handle 18 the shaft 135 must again be turned to remove the lug 136 from the groove 21 to free the handle for its axial return. The shaft 135 is also linked to a shutter 139 apertures in which allow the sending press key SS to be depressed only when the shaft 135 is in the turned position. Counting mechanisms are actuated each time the commutator and the auxiliary commutator are operated for the through passage of a tr