GB860254A - Improvements in means for producing signals from hand-written characters - Google Patents

Abstract

860,254. Automatic recognition of characters during writing. BETTS, A. J. May 7, 1959 [Oct. 21, 1958], No. 33646/58. Class 106 (1). In apparatus for recognizing characters from a manual tracing of the shape of such characters on a surface 15, Fig. 1, the surface consists of an irregular mosaic of sensing elements 16-1 to 16-9 and 16-X, e.g. electrical contacts, which are energized in succession by contact with the tracing stylus and cause successive operation of magnet serving, for example, to print the corresponding character on a typewriter. The sensing elements are insulated from each other and are divided into two groups, each group being connected in common to one side of a double-pole reversing-switch 18. Connections from this switch are made to the wipers of ganged stepping switches 19-0 and 19-P. The tracing stylus 12 is energized when applied to the surface 15 by the closing of pressure-switch 13, switch 14 opening at the same time. When the stylus engages a contact, e.g. 16-1, voltage is transmitted through switch 18 to the wiper of switch 19-0 which, being in the first position, energizes coil R1-0 of a relay R1. Had the first contact been one of the other group the connections would have been through the stepping switch 19-P to energize coil R1-P of the same relay. Relay R1 has two contacts R1-1 and R1-2, the former being engaged when coil R1-0 is energized and the latter when R1-P is energized. As the stylus moves from one contact to another one or other of a pair of stepping coils 28 is energized, a pawl-andratchet mechanism thereby turning the wipers to the next contact for connection to coils of relay R2. Each relay in succession is operated, moving up or down according as to whether the energizing contact is of one group or another and a circuit is set up on the pyramid of contacts to one of the output coils 10-a to 10-z and 10-2 to 10-9. The corresponding key of a typewriter is operated as soon as the stylus is lifted from the surface 15 to allow contact 14 to close and apply voltage to the selected coil. As the typewriter operates it closes contact 11 to reset all the relays and the stepping switches. As shown in Fig. 2 the letter " a " causes energization of the following contacts in sequence 1234x1x4 and this produces " O " and " P " signals in the order OPOPPOPP, thus closing contacts R1-1, R2-2, R3-3, &c. as shown in Fig. 1. The connection beyond contacts R8-2 is made through normally-closed contacts R9-2 to coil 10-a. For digits 2-9 switch 18 is reversed. Instead of electric contacts, photo-sensitive elements could be used, the stylus having a light at the tracing end. In the form of Fig. 4 a mosaic of rectangular contacts is used and circuit (Fig. 3) recognizes the traced character from the order of energization of the elements. In this circuit each element 16-1 to 16-15 is connected directly to an associated relay coil R1-R15. Relays R5 and R8 are of the kind which close different contacts on the first and second operations. All the contacts except 16-8 and 16-9 are disconnected by operation of the pressure switch but one relay is operated before this switch operates and another at the end of the trace as the stylus is lifted off the surface. One of relays R8, R9 is operated in between unless the first contact is 16-4 when relay R4 connects contacts R5 and R11 for intermediate energization, i.e. during the trace. A relay network produces a recognition signal as before. The stylus may be guided by a pantograph. The output may alternatively be applied to a teleprinter, a card or tape punch, magnetic tape apparatus, a counter or a calculating-machine. In such cases the character may be represented by combinational signals on more than one lead if more suitable.