Patent GB-409372-A (GB)
Title: Improvements in or relating to punching machines for duplicating perforated record cards
Filed: 1932-10-31
Abstract: 409,372. Selective punching-machines. BRITISH TABULATING MACHINE CO., Ltd., Victoria House, Vernon Place, Southampton Row, London. Oct. 31, 1932, No. 30592. Convention date, Dec. 15, 1931. [Class 31 (ii).] A punching machine for duplicating perforated record cards from a master card and in which a blank field on the master card may be skipped, is provided with means whereby the machine may punch data added to a field which was formerly blank. The invention is described as applied to the machine illustrated in Specification 362,529, in which hole-reading devices consist of electric brushes 17 each of which completes a circuit when it encounters a hole in the master card, and energizes an electromagnet 58 operating the punching and tabulating mechanism; and in the master card an eleventh or X-hole is provided to enable the machine to skip blank fields. According to the present invention, another or data-hole is provided in the master card so as to neutralize the action of the X-hole and allow data added to the blank field to be duplicated. This is effected by a relay 79, 75 which renders inoperative the magnet 73 controlling the tabulating mechanism whenever an X-hole accompanied by a data hole is read. A circuit from a source 39 is completed through contacts 67, the X-hole, eleventh magnet 47, and relay coil 74 ; and another circuit is completed through the data hole, one of the magnets 47, and the relay coil 79. This relay acts very quickly and opens the contacts 75 before the coil 74 can close its contacts, thus preventing duplication of the X-hole by restraining the magnet 47 from operating the corresponding interposer bar 52, but duplicating the extra hole in the master card. During the punching, contacts 67 will open and contacts 68 close by the mechanism shown in Fig. 1 and described below, but the circuit through magnet 73 and coil 74 will be inactive while the relay 79 is still energized and is holding the contacts 75 open. Contacts 75 close when contacts 67 open, but coil 74 being in the circuit through contacts 67 is not energized, and consequently magnet 73 is not energized. The machine will then duplicate the field which has been added to the card formerly blank. Referring to Fig. 1, when a magnet 47 is energized, an interposer bar 52 is moved to the right and rocks a bail 55 common to all the bars 52, thus closing contacts 57 and energizing a magnet 58 which depresses the punch-actuating member and selected bar 52. A bail 60 is also rocked and turns the arms 60<b>, 60<c> ; this raises a pawl 61 from a rack 10 and depresses a pawl 62 into the rack. The pawl 61 is loose on the shaft 60<a>, and when lifted is moved to the left by a spring. When the punch is fully depressed, contacts 57 are automatically reopened, the punch and bar 52 are restored to the normal upward position, and the bail 60 returns to the position shown, thus disengaging the pawl 62 from the rack and allowing pawl 61 to re-engage the rack. The rack then moves one step, carrying the master and blank cards one column space. The contacts 67, 68 are operated by the members 65, 69, 70 as described in Specification 362,529. To skip blank fields, a skip bar 76 is secured to the rack 10 and normally supports the reduced end 85, Fig. 2, of a bar 81 which is moved to the left and lifts the pawl 61 when the magnet 73 is energized ; the rack can then move when pawl 62 is raised. Notches 77 on the bar 76 correspond with the last column of each field of the master card, and allow the bar 81 and pawl 61 to fall and check the rack with the first column of the next field of the master card beneath the brushes, and if the column contains an X-hole, the machine will perforate this hole in the blank card and skip the next field.