Patent GB-815563-A (GB)
Title: Improvements in typewriters
IPC: B41J19/14
Filed: 1957-06-18
Abstract: 815,563. Typewriters. ZINT, G. June 18, 1957, No. 19114/57. Class 100(4) reverse writing type-lever machines, type actions, line spacing. In a typewriter in which typing is done by two banks of levers 316 during each reciprocation of a power driven carriage 99 so that every other line of the typed matter must be read backwards, two additional typelevers 327, 328 for printing oppositely facing arrow-like symbols are provided to indicate the direction in which the text has to be read. The type-levers 327, 328 are operated by a single key 300, link 361, actuator lever 344 which pivots at 343 on a horizontal stud 341 rotatable about a vertical axis so that the actuator 344, can be shifted to engage either the type-lever 327 or the type-lever 328. This shifting is effected by a slotted arm 351 adjustably secured on a sliding bar 350 automatically shifted at the end of each travel of the carriage by a mechanism which automatically rotates the platen 101 for linespacing. This mechanism is supported on a plate 121, Fig. 11, extending from a bar 25 fixed to the typewriter frame, and comprises a U bearing 123 supporting a ratchet wheel 127, and a pawl rocker 153 carrying a pawl 162, a finger 202, Fig. 9, and a roller 167 adapted to operate the rocker 153 when it is engaged by a cam 176 on a bar 175 which travels with the carriage. The rocker 152 is temporarily held in its elevated position by a trip finger 199 until the carriage is at the end of its travel whereupon it is released so the pawl 162 advances the ratchet 127 and automatically line-spaces the platen. The trip finger 199 is on a trip rod 189 which is moved in either direction by trip dogs 178, 182 as described in Specification 714,343. The downward swinging of the pawl rocker 153 also tilts a member 365, which through a lever 370, shifts the rod 350 to determine which of the type-levers 327 or 328 is to be operated. The connection between the rocker 153 and the tilting member 365 comprises an L-shaped swinging arm 372 pivotally mounted on the pawl carrier so it engages alternate ends of the member 365. The arm 352 is swung under the control and assistance of a snap-over spring control 382, 383, 384; the action being initiated by two trip members 379, 380 that move with the carriage 99 and which engage the arm 372. Key-levers. The key 301 is constructed with a ring to accommodate the thumb and is positioned so that the fingers correctly operate the ordinary keys. Letter-spacing. A key 300 similar to the key 301 for operating the arrow-like symbol type-levers, is operated for word-spacing and, via a linkage 304, 309, 310, 311, Fig. 1, raises a wedge 260 to radially move a control gate 255 which associates a continuously running motor 37 and toothed head to pick up one of an annular series of slidable pins 247 on a head fixed to the shaft of a helix carriage driving shaft 62. The control gate 255 is moved out of the path of the approaching stud so that its pin will be picked up by the driving -tooth to give the helix shaft 62 a partial rotation. If the key 300 is held depressed the helix shaft 62 will continue to rotate to lengthen the word spacing. Each time a character key is depressed the wedge 260 is operated momentarily to retract the gate 255 so that letter-spacing ensues.