Patent GB-786046-A (GB)
Title: Improvements in record-controlled office machines
IPC: B41J3/50
Filed: 1950-06-23
Abstract: 786,046. Statistical apparatus. DIRKS, G. June 23, 1950 [Oct. 1, 1948], No. 37228/54. Divided out of 786,021. Class 106 (1). In an office machine controlled by signals in record media, a plurality of synchronizing effects are derived from the data signals during each traverse of a record by sensing means to control storing, computing, printing, output, and/or other signal-operated means. As described, the rear of an electric typewriter, Fig. 1, comprises two magnetic tapes 1, 2 with sensing and step-by-step feeding means 8, 9, of the type described in Specification 786,031. Also, ledger account sheets or the like are fed from a box 10 to a printing device 11 preferably of the type described in Specification 786,022, [Group XVI]. A signal sensing head 16 and a record/erase head 17 may be adapted to be traversed up and down to co-operate with magnetizable areas on the sheets to read out old balances &c. The heads may also control the feed driving motor 13. The signals themselves are either single magnetic changes or a sequence of frequencies with gaps or phase-shifted sections. They may be related to a datum edge or perforation in the medium or a magnetic zero mark. In a first embodiment the detection of a " start " signal by the magnetic sensing head causes a pentode (Fig. 3, not shown) to conduct, energizing a relay which closes contacts 89, Fig. 2, in the circuit of a solenoid 65. This releases a shaft 93 for rotation through a slipping clutch and so drives various cam discs 95<SP>1</SP> ... 95<SP>6</SP> which operate contacts 90<SP>1</SP> ... 90<SP>6</SP> in a pre-arranged manner as the sensing head traverses the signal area and controls the contacts 89. In another embodiment (Figs. 5 and 6, not shown), three sensing heads co-operate with three channels on a magnetic tape, one channel containing zero or datum signals, another having signals with values proportional to the distances from the datum signals, and the third channel representing similar but complementary values. In this embodiment a cathode-ray tube distributer is employed, the cathode-ray being detected by an array of photo-cells, or secondary emission fields, or separate anode plates. Another embodiment employing a C.R.T.. distributer comprises a head 136, Fig. 7, for sensing a sinusoidal synchronizing signal on the input record medium. This signal is used to effect a circular scanning of the cathode-ray by applying two outputs from the amplifying tube 137 having a phase difference of 90 degrees to the separate deflection plates 128, 129. Alternatively, two synchronizing sinusoidal signals having 90 degrees phase displacement may be recorded on the record medium. A data signal picked up by the head 141 is amplified by a pentode 142 and applied as a positive pulse to the grid 119 of the C.R.T. The increase in beam intensity causes, by secondary emission from the target area 140<SP>0</SP> ... 140<SP>9</SP> on which the beam is directed, a voltage change which fires an associated gas tube 143<SP>0</SP> ... 143<SP>9</SP> to register the sensed signal. Specification 786,029 also is referred to.