Patent GB-908232-A (GB)
Title: Coding keyboard mechanism
IPC: H04L17/04
Filed: 1960-05-12
Abstract: 908,232. Printing-telegraph transmitters. SORABAN ENGINEERING Inc. May 12, 1960 [Oct. 30, 1959], No. 16828/60. Class 40 (3). A keyboard mechanism for selective operation of members by means of the keys comprises a control bail movable between a first and a second position, an actuator operated by a key disposed adjacent a surface of the bail and movable between an unactuated and an actuated position, the surface of said bail sloping away from said actuator which in its movement from its unactuated towards its actuated position engages the sloping surface of the bail which is moved from its first position towards its second position, and driving means responsive to the movement of the bail from its first position towards its second position for positively moving the bail to its second position, or holding it in the second position, and means responsive to the movement of the bail towards its second position for positively moving the actuator to its actuated position in which it is latched as long as the bail is in its second position. The sloping surface of the bail is formed by a wall of an inclined slot 103 located adjacent a part of the actuator in response to the operation of a key, and the bail is provided with a number of inclined slots numerically corresponding to the keys of the keyboard. The arrangement is described for the transmission of signals corresponding to an 8-unit code by notched code bars 21 having portions selectively cut away adjacent operating parts of the key levers or actuators 69 to permit selective movement of the bars 21, when released, to close corresponding contact members of a switch assembly 62 to form the appropriate code signal combination for transmission. Each key lever 69 has mounting portions 75, 77 sliding in washer members in frame portions of the apparatus, a portion 71 coacting with the recesses and cut-away portions of the code bars 21 and also a slotted portion 94 with a knife-edge part 96 normally disposed immediately above the front wall of an associated inclined slot 30 in the bail member 26. The initial downward movement of an actuator 69 moves the member 26 to the right, and through a pusher rod 99 and arm 101 operates a microswitch 102 to close the circuit of a rotary electromagnet 53 which through a cam 59 and arm 41 rocks a bail frame 13 carrying a rod 43 in engagement with a projection 31 on the bail member 26 positively moved to its second position, and, by means of the slot 98 in the portion 94 of the actuator 69, Fig. 6, effects locking of the key 69 in its operative position. The rod 43 also releases the code bars 21 having cut-away portions under the part 71 of the key-operated actuator to move to the right under the acti n o associated pairs of springs 48 provided for each code bar 21, and through pushers 64 to close corresponding movable contact members 67 of the assembly 62. Also, a switch 109 is operated by an extension member 113 of the bail 13 when the latter is rocked by the magnet 53. When the signal combination has been transmitted, the magnet 53 is de-energized, the bail member 13 is restored to its normal position in which the bars 21 are returned to their normal left-hand positions and the bail 26 is restored by spring 51 to its first position in which the operated actuator 69 is returned to its unoperated position. The part 71 of an actuator has a recess 86 disposed in line with a row of balls 87 having a very slight spacing so that the simultaneous operation of two or more keys is prevented. A space bar, Fig. 9 (not shown), extending across the keyboard is linked to the actuator operated by the key corresponding to the transmission of the code combination for space." A circuit for effecting the release of the magnet 53 when a code signal combination has been transmitted is described in connection with Fig. 11 (not shown). U.S.A. Specification 2,836,809 is referred to.