Patent GB-500429-A (GB)
Title: Improvements in or relating to railway signalling systems
IPC: B61L1/16
Filed: 1937-08-04
Abstract: 500,429. Railway signalling systems. STANDARD TELEPHONES & CABLES, Ltd., BROWN, A., and MARSHALL, T. A. Aug. 4, 1937, No. 21472. [Class 105] Each end of a railway track section over which traffic may pass in either direction is provided with a rotary step-by-step axle-counting device responsive to the direction of passage and operated by electromagnetic reciprocable armatures ; these two axle-counting devices operate two rotary storage devices and the whole apparatus is so arranged that' simultaneous operation of the axle-counting devices at each end of the section by two incoming of two outgoing axles causes two axles to be counted in or out and that simultaneous operation by an incoming axle at one end of the section and an outgoing axle at the other end does not resultin relative movement between the two rotary storage devices. In the arrangement shown in Figs. 1 and 2, the axles are counted by reciprocable armatures acting as escapements for discs C, F, H, J, which are frictionally mounted on a constantly rotating shaft A. The discs carry bevel pinions D which engage with bevel toothed discs B, E, G. I, K, of which disc B is fixed in space and the others are free on the shaft A. Directional treadles at the ends of the track section respectively control the movement of the discs C, F and H,J. An axle entering at one end causes the escapement disc C to advance one step. The escapement disc C drives the disc E one step forward and this in turn drives the disc G one step back since the escapement disc F is held by its escapement not being operated. The disc G similarly drives the disc I forward and the latter drives the final disc K backward so to register the entry of one axle. If an axle enters at the other end the escapement disc H moves forward and drives the disc I forward and this in turn drives the final disc K backward. It will be seen that simultaneous entry of an axle at each end would move the final disc K two steps backward since the two escapement discs C, H would actuate the gearing in an additive manner. Outgoing axles operate the apparatus in a similar manner; for instance an outgoing axle at the above-mentioned other end causes the escapement disc J to move forward whereby the final disc K is moved one step, forward so to count out one axle. Fig. 3 shows an arrangement in which oppositely acting pawls O, P are operated according to the direction of axle movement so as to move a shaft A forward or backward one step. Assuming that the axle first operates contact TRA and then contact TRB of a two-arm treadle at one end of a section it will be seen that a magnet X is energized when the contact TRA is closed and that when later the contact TRB is closed a magnet Z is energized (over a front contact x1). Thus the pawl P is raised and moved into engagement with the ratchet wheel N. When the contact TRA opens, the magnet X is de-energized and the pawl P is retracted by a. spring to move the ratchet N one step, it being noted that the magnet Z is not immediately de-energized since the contact xl remains closed almost until the end of the downward movement. If this axle stops on the second arm of the treadle and then moves backward it will now be counted out since as soon as it had been counted in a magnet Y was energized (back contact x2 having closed) and therefore as soon as the contact TRA is again closed (by the backward movement of the axle) a magnet W will be energized to place the raised pawl O into contact with the ratchet wheel M. Each end of the track section would be provided with this apparatus and the two shafts A would operate a differential gear a crown wheel of which would then be stepped forward or backward as each axle entered or left. With axles antering the two ends simultaneously the crown wheel would be operated in an additive manner. An alternative arrangement for stepping the shaft A is shown in Fig. 4. If the magnet X is the first to be operated it raises its pawl P and also moves a block U into a position to engage the top of a projection V and thereby to prevent the rise of the other pawl O. When the magnet Y is energized a second armature S thereof pulls the pawl P of the first magnet X into engagement with the ratchet wheel N by reason of the block U1 engaging the side or the projection VI. When the axle moves off the first arm of the treadle the magnet X is de-energized and causes the ratchet N to be moved one step. The device is now in readiness to count the axle out if it should now move backward since the magnet Y is still energized and has now raised its pawl O. Fig. 7 shows an arrangement in which a shaft is given one rotation at the passage of an axle. The two ends of the shaft have a crank-pin CP1, CP2 arranged at 120‹ and engaged by lever armatures AR1, AR2 of the magnets TA, TB operated by the two arms of the treadle. A spring SP holds the shaft in normal position. On passage of an axle which first energizes the magnet TA and then the magnet TB, the armature lever AR1 will first move the shaft 120‹ and then the armature AR2 will, move the shaft a further 120‹ in the same direction since crank-pin CP2 will have moved to the former position of crank-pin in CP1 ; when the axle has completely passed the spring SP will effect the final 120‹ movement, since crank-pin CP1 would be at the position of the crank-pin CP2. Fig. 10 shows an arrangement where large numbers of axles are to bo counted. The two shafts 14 are operated in the manner of Fig. 7, by the countings effected at the two ends of the section and drive through worm gearing 19 a differential gear having a crown wheel 53 meshing with a smaller wheel 35. The crown wheel 53 carries a spring-oressed pin 33 which is depressed by an arm 34 on the wheel 35 only when the pin and arm register ; the depressed pin 33 operates a stud 26 of an electric contact assembly 55. With each axle operating the crown wheel 53 through <1/>50 revolution and with the crown wheel 53 and the smaller wheel 35 having 80 and 22 teeth the apparatus can deal with trains up to 550 axles. Fig. 12 shows the circuits associated with the apparatus of Fig. 10. Axles entering or leaving at one end of the section actuate the treadle ET to drop the relays TRA; TRB which by their contacts tra2, trb2 energize the magnet RMA, RMB to rotate the particular shaft 14. Axles entering or leaving at the other end of the section rotate the other shaft 14 by means of the treadle LT, relays TRC, TRD, and magnets RMC, RMD. The response of the axlecounting apparatus is checked in the following manner. Entry of an axle drops a relay GRB (for instance by opening a contact tral,) which opens its contact grb3 in the stick circuit of a relay GRA which thus opens its contact gra2 in the circuit of a relay LR. The response of the axle-counting, apparatus causes a contact NC to energize a, relay GR which closes its contact gr1 to pick up the relay GRA. When the section is again free of axles the relay LR, is again energized over contact NC, front contacts grb2, gra2, and back contact gr3. It will be seen that the relay LR can only be re-energized if the relay GR has been energized to pick up the relay GRA and has been subsequently dropped to allow back contact gr3 to close. For this action in the relay GR it is necessary that the axle-counting apparatus contact NC be actuated and restored. If the apparatus fails to return to normal the signalman operates a key RK2 to apply potential over back contact lr2, key contact RK2, and back contact hrb2 to a relay HRA ; a front contact hra3 energizes a relay HRB whereby the back contact hrb2 is opened and thus the relays HRA, HRB vibrate and at their front contacts hra1, hrb1 energize the magnets RMC, RMD to rotate the axlecounting shaft until the normal state is reached and the relay LR is re-energized to open the back contact lr2. Specification 447,866 is referred to.,