Patent GB-766441-A (GB)
Title: Improvements relating to electromagnetic relay counting systems
IPC: B61L7/08
Filed: 1953-11-30
Abstract: 766,441. Counting-apparatus. GENERAL RAILWAY SIGNAL CO. Nov. 30, 1953 [Dec. 31, 1952], No. 33242/53. Class 106 (1). An electromagnetic relay counter is charac. terized in that counts are registered according to a binary code, any one count requiring the move. ment of only one relay. The counter is described when adapted for use as a circuit or channel selector. In Fig. 1, vertical " dash " lines indicate contacts associated with six counting relays V to V6, each relay being of the " neutral " type and each having two windings, a " pick-up-" and a " stick " winding. The position in which the contacts are shown, all in a " dropped down " position, is the starting position, with each relay unenergized, and corresponds to a count of zero, or, in the embodiment shown, to a count of 64. Terminals marked " (+) " are connected to the positive terminal of a battery, those marked "(-)" to a negative terminal. The input to the counter is via a relay CR, each movement of it, whether it be a pick-up or a fall-down registering one count. A relay is picked up by energizing its pick-up winding, the lower winding in Fig. 1, and upon being picked up it completes a stick circuit which energizes its stick winding. The stick winding then remains energized until it is desired that the relay should drop down. Two examples follow. It will be seen from the code, Fig. 2 (not shown), that when the counter registers 15 the positions of the relays V1 to V6 are " up," " down," " down," " up," " down," " up," respectively, and that of relay CR is "up." In this position relay V1 is held up by a stick current passing from (+) to front contact 25, front contact 26, through the stick winding of relays V1 to ( - ), the stick circuit for relay V4 extends from ( - ) through the stick winding of V4, front contact 38, back contact 37 to ( - ), and there is a similar circuit for the stick winding of V6. On the next count, count 16, relay CR drops, thus breaking the stick circuit for relay V1 and relay V1 drops. On count 17 relay CR is picked up and the pick-up winding of relay V5 is energized, the circuit including (+) to front contact 10, back contact 20, back contact 21, back contact 22, front contact 23, pickup winding of V5 and front contact 18 to ( - ). Thus relay V5 is picked up. On count 16 the stick circuit for V6 extended through the back contact 32 to (+). When V5 picks up on count 17 this path to (+) is broken, but it is immediately remade through front contact 32 to front contact 141 and to (+). In order that the relay V6 shall not fall during the change-over its time constant is suitably adjusted by a resistor in parallel with its stick circuit. The other relays are similarly equipped. The lower contacts in Fig. 1 perform the circuit or channel selecting. There are 32 of these contacts on relay V6, each of them, excepting the lowest, being associated with the channels. From the above it will be seen that at count 16, with relays V1 to V6 " down," " down," " down," " up," " down," " up," respectively, the (+) at contact 42 will be connected to channel 16, CH16, and on count 17 it will be connected to channel 17, CH17. Three other embodiments are described, the second, Fig. 3A (not shown), using neutral relays having two windings as in Fig. 1, but unlike Fig. 1 when a relay is to drop down instead of its stick circuit just being broken, a negative current is applied to its pick-up winding to nullify the effect of the stick current and thus cause the relay to drop and in dropping it cuts off current to both its coils, the third, Fig. 4 (not shown), using magnetic stick relays each having one winding, and the fourth, Fig. 5 (not shown), again using neutral relays as in Fig. 1, but unlike Fig. 1, the upper winding serves both as a pick-up and as a stick winding and its lower winding serves only to nullify the stick current when the relay has to be dropped. Specification 697,888 is referred to. Reference has been directed by the Comptroller to Specification 734,013.