Patent GB-793095-A (GB)
Title: Improvements in or relating to variable spacing mechanisms for typewriting machines and the like
IPC: B41J19/58
Filed: 1956-07-18
Abstract: 793,095. Variable spacing mechanisms for typewriters and the like. OLIVETTI & CIE. SOC. PER AZIONO ING. C. July 18, 1956 [July 23, 1955; July 10, 1956], No. 22202/56. Class 100(4) A variable spacing mechanism of the kind having fixed and movable dogs co-operating with a toothed escapement wheel and means for preventing the movable dog from re-engaging the escapement wheel until its movement to the spacing stop is complete, has means to retard the action of the re-engaging means to enable the movable dog to complete its return movement before the escapement member is re-engaged. When a character key is pressed, one of four stop pins 38, Fig. 2, is set, through linkages and rails not shown, rocker 26 is rocked by the universal bar to disengage movable dog 33 and engage fixed dog 28 with escapement wheel 25, and projection 34 is disengaged from slot 35. Sector 36 and slide 29 are moved clockwise by springs 53, 54, the former more quickly than the latter, to lock rocker 26 in the rocked position irrespective of the return of the universal bar to its normal position. Arm 37 of sector 36 is arrested by stop pin 38 and when projection 34 arrives over slot 35 it drops in whereby rocker 26 rocks back re-engaging movable dog 33 and disengaging fixed dog 28. The spacing spring moves wheel 25 until slide 29 is arrested by pin 30 thus completing the character spacing. A bent-over lug 56 prevents projection 34 overshooting slot 35. To ensure that the correct tooth of wheel 25 is always caught during tabulating and carriage return operations two auxiliary escapement wheels 57, 58 integral with wheel 25 are provided. During carriage return, rack 21 is moved to the right, Fig. 4. causing finger 72 of silencing disc 71 to disengage movable dog 33 from escapement 25. At the end of the movement an abutment of the left hand margin stop causes lever 61 to move pawl 59 into engagement with wheel 57 thus arresting the carriage. The carriage recoils under its spring on release, simultaneously releasing pawl 59 and dog 33 which reengages wheel 25 to retain the carriage. Tabulating. Depressing a tabulator key moves one of stop fingers 77, Fig. 3, upwards and rooks lever 85 counterclockwise, whereby lever 87 moves slide 29 upwards as seen in Fig. 4, disengaging dog 33 from escapement 25, thus releasing the carriage. When stop pin 79 hits finger 77, plate 78 is moved so that lug 90 rocks bail 92, and, with it, slide 97, clockwise about shaft 93, Fig. 4, bringing pawl 98 into engagement with escapement 58 which pulls slide 97 down and arrests the carriage. This movement of slide 97 to left, Fig. 3, causes lug 99 to rock detent plate 81 counterclockwise, releasing lever 76 which allows stop finger 77 to disengage, and plate 78 and lever 87 to return to normal, in turn releasing slide 29 to re-engage movable dog 33 with wheel 25. Restoration. of plate 78 allows lug 90 to release bail 92 whereby pawl 98 disengages wheel 58. Stop lug 105, Fig. 4, on slide 29 prevents excessive retrograde movement, due to no stop pin 38 being set, of dog 33 when disengaged by either finger 72 or lever 87, thereby stopping excessive travel of the carriage after tabulation, or excessive recoil after return travel. In a modification, depressing a character key sets a stop pin 128, Fig. 6, in the path of an edge 127, not shown, of slide 122. Also, cam 107 throws universal bar 108 to right and lug 136 of the latter rocks lever 133 counterclockwise whereby portion 137 of cam slot 132 raises pin 131 rocking rocker 118 clockwise about pins 119. Pin 131 is not affected by further movement of lever 133. Rocker 118 disengages loose dog 121, which retrogrades to stop 128, from wheel 117, and engages dog 120 therewith. As the universal bar 108 returns to normal, lever 133 rocks clockwise, spring design being such that bar 108 returns quicker than lever 133. Rocker 118 is not allowed to return to normal until pin 131 arrives over sloping portion 137 of the cam slot 132. Thus a time delay is provided in which loose dog 121 completes its retrograde movement. In addition, part 138 of slot 132 prevents lever 133 rebounding from pin 131 under heavy impacts from the universal bar. Wheels 57, 58 may be replaced by a single wheel adapted to co-operate with pawls 59 and 98.