Patent GB-797669-A (GB)
Title: Improvements in or relating to record card feeding devices
Inventor: BAILEY ERIC
IPC: G06K13/077
Filed: 1954-12-09
Abstract: 797,669. Selective punching machines. BRITISH TABULATING MACHINE CO. Dec. 9, 1954, No. 35670/54. Class 31 (2). [Also in Groups XVI, XIX and XXIX] Record card feeding apparatus having a card carriage, a pawl 1, Fig. 1, co-operating with a rack 11 to effect step-by-step movement of the carriage, electromagnets 4, 5 for respectively engaging the pawl with, and disengaging the pawl from, the rack, first and second energizing circuits for energizing the electromagnets 4, 5 respectively, means for operating the second circuit, electrical delay means for operating the first circuit at a predetermined time after operation of the second circuit, and means for rendering the second circuit inoperative consequent upon operation of the first circuit. An armature 7, Fig. 1, common to the electromagnets is connected to a pivoted lever 8 provided with a tongue which engages a slot 10 in the pawl 1. When the electromagnet 5 is energized and the electromagnet 4 de-energized, the armature moves anticlockwise so that the pawl 1 is disengaged from the rack 11 which moves towards the right under the action of a spring. The rack carries an extension 13 which engages an insulating block 14, when the last column of the card is beneath the punches, to close contacts 15. The contacts 15 control energization of a magnet which causes the card to be ejected from the carriage. Energization of the electromagnets 4, 5 is controlled by gas-filled thermionic valves V1, V2 respectively. Operation of the pawl 1 is initiated by a pair of normally-open contacts 16 which close as the armature of the punch plate, as described in Specification 562,278, which is referred to, reaches the limiting position. The valve V1 will be conducting, as the contacts 16 close, to hold the pawl in engagement with the rack. When the contacts 16 close, a positive pulse is fed from a positive supply line 17 via a capacitor 21 and a resistor 22 to the control grid of valve V2. This positive pulse raises the grid voltage of valve V2 sufficiently to cause it to fire. The anode of valve V2 is connected to the anode of valve V1 by a capacitor 26. Accordingly, when valve V2 fires, valve V1 is extinguished. This causes the pawl to be disengaged from the rack. To limit the movement of the card carriage to one column, the grid of valve V1 and the cathode of valve V2 are coupled together by an electrical delay circuit comprising relay contacts R1b, a manuallyadjustable resistor 31 and a capacitor 33. Neon lamps 28 show when the valves are conducting. A single column spacing without punching may be obtained by depressing a space key 34. To secure skipping, a plug connection is made between a socket 35 and a socket 36 of a column emitter 37, the socket 36 connected being that which corresponds to the column immediately before the first column to be skipped. When a circuit is completed to the socket 35, the relay R1 is energized to establish a holding circuit through contacts R1a, R3a and 38. The contacts 38 open on the last column of the card. Contacts R1b open to break the coupling between the valves V1 and V2, so that the firing of valve V1 is prevented and the electromagnet 5 remains energized. A plug connection is also made between the socket 36 corresponding to the last column to be skipped, and a socket 39. This causes energization of a relay R3 when this column is reached. Contacts R3a open to break the holding circuit for the relay R1. Contacts R1b then close which causes valve V1 to fire and energize the electromagnet 4 to re-engage the pawl with the rack. To feed the card to the last column position, a reset key is depressed to close contacts 41. This energizes a relay R2. Relay contacts R2b close to shunt contacts R1a and R3a, thus energizing the relay R1. Contacts R2a close to hold the relay R2 energized until the contacts 38 open. Contacts R2b prevent the relay R1 being de-energized if the relay R3 is energized as a result of some intermediate column being plugged to control the end of skipping. In this way, the firing of valve V1 is prevented until the last column of the card reaches the punching position. The relay R2 may also be engaged by making a plug connection from one of the sockets 36 to a socket 40. The machine described in Specification 562,278 may be modified to allow column by column sensing of a card, the punches being replaced by sensing brushes or a photo-electric sensing unit. In this case, the contacts 16 are replaced by a commutator or cam-operated contact driven at such a speed that the card is fed at the desired rate. The contacts 16 may also be replaced by a commutator if a punching mechanism is used in which the punches are operated by a rotary cam. Specification 362,529 also is referred to.