GB674941A - Improvements in a power operating mechanism for a typewriter or like machine - Google Patents

Abstract

674,941. Typewriters &c. ROYAL TYPEWRITER CO., Inc. Dec. 17, 1948 [Feb. 3, 1948], No. 32739/48. Class 100 (iv). Relay actuation. In a typewriter, adding machine, calculator, &c. the actuator of a type lever, carriage return mechanism, back spacer, line spacer, case shift mechanism or tabulator is power operated through a relay action wherein a driving member is coupled to the actuator by an interponent connected to the actuator, the interponent being biased toward operative engagement with the driving member, but normally held free therefrom by key-controlled means effecting snap operative engagement, the said means being responsive (a) to return movement of the key and preferably also (b) to completion of the required actuation, to reset the interponent clear of the driving member. The response (a) ensures that temporary key depression when the driving member power source is disconnected does not " cock " the mechanism for actuation when the power source is reconnected, while response (b) prevents repeat actuation if the key is held down. As shown a snatch roll 118 driven by an electric motor is connected to a type-bar 101 by depression of the appropriate key 143, 143a ... having a projection 165, 165a or 165b (of such lever-length from the key pivot 144 or 144a as to provide equal vertical key-depression in all banks) which rotates a spring-loaded lever 147 carrying a spring flipper 151; the flipper depresses an actuator 119 about its floating pivot 121 so that a trigger 136 thereon is rotated by a fixed stop 129 until its nose 138 is transferred from the holding surface 139 of a spring pawl 132 to its cam surface 140, whereupon the pawl snaps into engagement with the snatch roll 118; if the latter is stationary, subsequent key release allows a spring 127 to lift the actuator 119 so that a fixed stop 124 causes the trigger 136 and pawl 132 to be restored to the position shown; if however the roll 118 is being driven the actuator 119 is pushed forwards, its front ends 123, 123a sliding respectively on the stop 129 and in a comb guide 120, while its rear end, through the pivot 121, actuates the appropriate lever 105, 105a ... which is linked at 104 to the type-lever and at 108 to the universal bail 110 of the carriage escapement. Movement of the parts carries the pawl 132 out of range of the roll 118 and the contact surface 159 of the actuator out of range of the flipper 151, whereupon the spring 127 lifts the actuator and restores the trigger and pawl as above; the type-lever and actuator are finally restored to the position shown by a spring 113, the flipper 151 yielding for this purpose if the key has not been released. As shown the stops 124, 129 are of comb form, each tooth being bent for timing- adjustment of its associated action; in another form adjustment is partly by bending the horns of the trigger and partly by rotating a rod of semi-circular cross-section replacing the stop 129.