ES363443A1 - Automatic letter underscoring mechanism - Google Patents

Abstract

A typewriter includes a key 65 which when depressed acts, on subsequent depression of a character key 41, to effect printing of the selected character without an associated letter space movement, followed by automatic printing of a predetermined character such as underscore and a subsequent letter space movement. The typewriter comprises a single element printing head 11 actuated on depression of a character key 41 by a mechanism (not shown) acted on by lugs 43a during leftward motion of an interposer 43 under the impulse of a filter shaft 51. The printing head 11 is advanced in the letter space direction by an excapement mechanism through a linkage 55, a lever 57 and a torque bar 59. On depression of the key 65, the key is latched in place by a slot 73 engaging a frame 71 owing to a spring 79, a pin 81 thereby acting to depress a bar 87 into a position such that a step 91 thereof is in the path of a blade 53 of the filter shaft 51. On depression of the character key 41, rotation of the filter shaft is initiated through a bail 45. The selected character is impressed, and simultaneously the bar 87 is driven leftward to rotate a ratchet-wheel 97 and coupled cam 109 so that a follower 113 is urged to the right and the escapement linkage is broken by displacement of the lever 57 away from engagement with the bar 59 by engagement of an end 125 of the cam follower 113 with a portion 127 of the lever 57. The rotation of the cam 109 also acts to draw a follower 129 downwardly, a portion 141 thereof depressing a underscore interposer 63. A second cycle of the filter shaft 51 is thereby initiated, causing impression of an underscore. Simultaneously, the bar 87 is again impelled to the left to rotate the ratchet-wheel 97 and cam 109 further. The follower 113 is thereby drawn to the left by a spring 121, to reconnect the lever 57 with the bar 59 and permit the operation of the letterspacing escapement mechanism. The follower 129 returns to its inoperative position with the underscore interposer 63. The key 65 remains latched in its operative position for continuous underscoring until manually released. A ball interlock 20 is provided to prevent actuation of a second key before a printing and underscoring cycle is completed.