Patent GB-767005-A (GB)
Title: Improvements in or relating to counters employing magnetic cores
Inventor: DREWE JOHN
IPC: H03K25/00
Filed: 1953-04-14
Abstract: 767,005. Electric counting-apparatus; statistical apparatus. BRITISH TABULATING MACHINE CO., Ltd. April 5, 1954 [April 14, 1953], No. 10166/53. Class 106 (1). [Also in Group XXXIX] In a scale-of-N counter, a train of pulses to be counted is applied to a winding on a magnetizable core with a substantially rectangular hysteresis characteristic, the value of the voltage time integral of the pulses being such that N - 1 pulses will change the flux state of the core from saturation in one direction to saturation in the other in a series of discrete steps, and control means controlled by the voltage across an impedance (e.g. the operating coil of an electromagnetic relay), in series with the core winding, is operated when the core is driven into saturation in the other direction, the core then being reset to the first saturation state. Fig. 1 shows two scale-of-ten counters forming denominations of an accumulator arranged to be controlled by record cards, Fig. 6, in which each decimal digit (9-0) is represented by a differentially positioned hole in a corresponding column. The " 9 " to " 0 " times of a cardreading cycle are each divided into portions A and B. During A times, cam-controlled contacts CB1, CB2, Figs. 2 and 6, complete energizing circuits for relays S1, S1<SP>1</SP> when a brush 18 senses a hole in a corresponding card column. During B times, cam-controlled contents CB3, CB4, Figs. 1 and 2, complete circuits across the positive and negative supply lines to supply data-entry pulses to the accumulator, the number of pulses in each denomination corresponding to the differential time at which relay S1, S1<SP>1</SP> is energized to close its contacts Sla, S1a<SP>1</SP>. When, e.g., contacts S1a are closed, a circuit is completed from CB3 through connected plug sockets 34, 35, contacts S1a, condenser 3, core winding 5, rectifier 24, contacts 30 (closed for read-in or read-out) and CB4. As condenser 3 charges, the current in winding 5 causes transformer core 6, which has a substantially rectangular hysteresis characteristic, to change from one saturation state to the other, the core being returned to its initial state by bias winding 7. A negative pulse, having a constant voltage time integral, is thus induced in winding 8 and passed through rectifier 13, relay contacts 9A, relay 9 and winding 14 of core 20. This core, having a hysteresis curve as shown in Fig. 5, is arranged to pass from one condition of magnetic saturation 123 to the opposite condition in nine steps 124-131 and 133 in response to the pulses, and operates as a highimpedance or choke which prevents condenser 15, Fig. 1, charging sufficiently to operate relay 9 at the end of the pulse, until the core reaches the saturation condition 133. The relay is thus operated to represent " 9 " and is then held through a circuit comprising resistor 17, contacts 9C, reset winding 21, the current through which resets core 20 to its initial state 134, Fig. 5, and contacts 10a. The next (tenth) pulse from winding 8 is diverted through contacts 9B to charge condenser 16 and thus operate relay 10 which is held by a circuit from contacts CB6, Figs. 1 and 2, through hold winding 10H and shifted contacts 10a, the hold circuit for relay 9 being broken. Relays 9 and 10 close carry contacts 9d, 10b, similar contacts, such as 9d<SP>1</SP>, 10b<SP>1</SP>, being provided for higher denominations, whereby all carries are effected simultaneously when contacts CB7, Figs. 1 and 2, close at " 0 " B time. These contacts supply a positive potential, higher than that connected to CB3, to the " 10 " carry contacts, and if, e.g., 10b are closed, a circuit is completed to the next higher denomination through line 22<SP>1</SP>, winding 51, condenser 3<SP>1</SP>, contacts S1a<SP>1</SP> and CB3 to charge the condenser, a negative count-operating pulse being obtained from coil 8<SP>1</SP> at the end of the B pulse from CB7 when 3<SP>1</SP> discharges. The " 9 " contacts connect the carry B pulses from CB7 over lines such as 22<SP>1</SP>, 23 to higher denominations. The accumulator may be reset by operating a relay 33 (not shown) which closes contacts such as 33a, 33b which complete circuits through reset windings 21, 21<SP>1</SP> and shortcircuit relays 9, 9<SP>1</SP>. Read-out is effected by applying ten B pulses and suppressing carries, this obtaining a differentially timed A pulse, through contacts such as 9e, 9e<SP>1</SP>, Fig. 6, and CB1, CB2, representing the digit in each denomination ; contacts 32a, 32b are closed to by-pass sensing contacts S1a, S1a<SP>1</SP>, contacts 31a are closed to add a " 0 " B pulse through CB5, Figs. 1 and 2, and contacts 31b open the carry circuit from CB7. The accumulator may be duodecimal, the " 9 " relays then being operated after 11 steps. In another form (Fig. 7, not shown), the rectifiers 13, 13<SP>1</SP> are reversed and the count registration, for data-entry and carry, is made in response to the trailing, not the leading edge of the B pulses. The " 9 " and " 10 " relays may be replaced by thermionic trigger circuits and diode gates or by magnetic switches.