Patent GB-863431-A (GB)
Title: A method of and apparatus for automatically recording or indicating handwritten characters
Inventor: TOWNSEND DEREK THOMAS
IPC: G06K9/22
Filed: 1958-04-08
Abstract: 863,431. Recognizing traced character shapes. LAMSON PARAGON Ltd. July 2, 1959 [April 8, 1958], No. 11118/58. Class 106 (1). A character is recognized as it is being written on a surface by four separate electrical circuits which are energized on each movement upwards, downwards, to the left or right, respectively, made by the writing instrument. In the form of Fig. 1 the surface is composed of a matrix of downwardly-movable squares arranged in columns and rows, the squares of each row being mechanically linked as shown in Fig. 2 to operate a relay corresponding to that row, via a contact S. The columns have similar relays so that for each square depressed by the writing instrument, two relays are operated. Contacts of the column relays R1-R6, Fig. 3, are interconnected so that movement to the left by the writing instrument energizing, say, relays R3, R2 in succession energizes relay LR and movement to the right energizes relay RR. Upward and downward movement similarly, through the row relays, energize corresponding relays UR and DR. The four " direction " relays are interconnected so that only one may operate at a time. In Fig. 4 energization of " down " relay DR closes contacts DRX and DRX1 to DRX5 which energize subordinate relays DR1-DR6. Each of these relays has hold contacts al and three contacts b1 applying the voltage to contacts, say URX1, LRX1. and RRX1 in the next row for energization of the corresponding subordinate relays so that according to the sequence of operation of the relays DR, UR, LR and RR certain ones of the subordinate relays are energized. For each character the sequence of movements is different and, accordingly, the subordinate relays are energized in a different pattern. Further contacts of these relays are inter-connected to produce can output on a lead indicating the character sensed. In the form of Fig. 6, the writing instrument 10 is connected to rods 11 and 12 set at right-angles and sliding on guides 13, 14. These are each linked to differential gear mechanisms in such a way that rotation in one direction closes one contact and rotation in the other direction closes another contact so that the four direction relays are energized as before. Instead of using a differential gear mechanism, rotation of the guides 13, 14 may alter the value of a resistance connected in a bridge circuit, a follow-up device always serving to balance the bridge. The opposite relays, say UR and DR, are connected across the bridge via oppositely-poled diodes so that outof-balance in one direction energizes relay UR and out-of-balance in the other energizes relay DR. In a further form the relays are operated by contacts made on a conductive central rod 31, Figs. 10 and 11, which is normally spring- biased to a central position but which is displaced to engage contacts 33L or 33R, 33U or 33D as the writing point is moved over the surface. These contacts are connected to the four direction relays and the character written is recognized as before. Specification 825,808 is referred to.