GB238296A - Improvements in or relating to record-card-controlled statistical machines - Google Patents

Abstract

238,296. British Tabulating Machine Co., Ltd., (Tabulating Machine Co.). May 14, 1924. Statistical machines, electrically operated, have controlling means comprising a primary circuit and a controlling circuit. This controlling circuit includes the card-reading devices 13, 14, the electromagnets 40 for counters or sorting or printing mechanism and a secondary winding 54, while the primary circuit includes a source of current, a primary winding 52 and a current-varying device 58 driven in synchronism with the card-feed. These windings 52, 54 are coupled together inductively, preferably to form a set-up transformer, 53 being the usual core. The primary circuit also includes a card-operated contact 24, a balance resistance 51 of the iron wire type having a positive temperature coefficient and has a condenser 59 shunted across the current-varying device. The machine is started by depression of key 27, whereupon shunt circuits are established through 33, 23 and 35 to keep the machine running while there are cards in it. The contacts 23, 24 are closed by a common card lever 22, and the primary circuit is tapped off a potentiometer resistance 47 by taps 48, 49. The current-varying device comprises a cam 58 rotated once per card cycle so as to close contacts 56, 57 immediately before each index point in a column comes under its brush and to break these contacts at the instant that each index point is under the brush. If necessary, multiple-contactors 58 &c. and multiple transformers may be used. Specification 199,356 is referred to.