Patent GB-964960-A (GB)
Title: Improvements in or relating to type printing apparatus
Inventor: JAMES FREDRICK
IPC: H04L17/24
Filed: 1963-07-11
Abstract: 964,960. Selective printing. CREED & CO. Ltd. July 11, 1963, No. 27522/63. Heading B6F. [Also in Division H4] Printing apparatus e.g. an electric typewriter or a teleprinter, which is operated by electric signals of a code including printing and non- printing combinations, comprises a first set of members 13 adapted to take up positions representative of the elements of the code and to actuate character-selecting means when the members 13 are in positions representative of a printing-code combination, and a second set of members 15 each of which can move from a first position to a second position to inhibit operation of the character-selecting means when the first set are in positions representative of a non-printing code combination. Type selection.-As shown, a type head 1 carried by a shaft 61 is selectively positioned to print a required character by a known aggregate motion mechanism 3 . . . 8 including six input members such as 6, 7, 8 (three only shown) each corresponding to one bit of a sixbit code. Pivoted to the end of each input member 6 . . . 8 &c., is a slat 9 and it is by selective rightward movement of the slats against the action of springs 10 that the mechanism 3 . . . 8 is operated. A bar 13 guided for lengthwise sliding movement in slotted frame members 14 is provided for each slat 9, and all the bars 13 are simultaneously moved to the right against the action of springs 22 at the beginning of a selecting operation, by cams 21 on a shaft 31 driven by a one-revolution clutch 59 energized by a signal. At its right-hand end each bar 13 has a member 33 forming an armature for a solenoid S. There are six solenoids, one for each bar, and these are energized or not according to code signals received so that the bars 13 corresponding to energized solenoids are retained in a rightward position and the remainder return to the leftward positions under control of the cams 21 and springs 22. A pin 32 on each bar engages a slot 38 in a lever 37 itself having a pin-and-slot connection 39, 40 with an interposer 41 fixed to a bar 42 common to all the interposers. Each interposer 41 has a part 43 which, if its bar 13 is held by its solenoid 5 being energized, is positioned behind a projection 44 on the corresponding slat 9. The bar 42 is carried by a lever 48 having a roller 49 running on a cam 50 carried by a shaft 51 connected by a slipping clutch 52 to a motor drive. The shaft 51 is normally held stationary by a pawl 54 engaging a tooth on a disc 53 fixed to the shaft. After the bars 13 have been set, a solenoid TS is energized by a switch controlled by shaft 31, to withdraw the pawl 54 momentarily thus allowing the shaft 51 to make one revolution. During this revolution, the cam 50 moves the bar 42 with the interposers 41 to the right, and those interposers which have been moved by their bars 13 to cause engagement of parts 43, 44, displace the corresponding slats 9 to the right and thus effect selection of the required type face. Subsequent de-energizing of the solenoids 5 allows the parts to return to their initial positions under the action of their returning springs. Combinations of the slats 9 may be moved mechanically from a keyboard to select a type. Rendering type-selection and impression mechanisms inoperative for non-type-selecting signals.- Situated above the bars 13 and movable at right-angles thereto are bars 15, there being one bar 15 for each non-printing code signal. These bars 15 are urged to the left by springs 20 but are normally held rightwardly by the engagement of the bars 13 with the right-hand edges of slots 16 in the bars 15 which slots also allow of the lengthwise movement of the bars 13. If the code signals received represent a non- printing combination, and the bars 13 have been set thereby, a combination of notches 17 in the bars 13 allows one of the bars 15 to move leftwardly. During such movement the operative bar 15 opens a switch C in the circuit of the solenoid TS so that no revolution of the shaft 51 occurs, the bar 42 is not moved and hence the slats 9 are not moved to effect a setting of the type-head 1. A second switch similar to the switch C or a mechanical linkage may be actuated by a displaced bar 15 to stop an impression movement of the type-head or the movement of a platen into printing engagement with the type-head. To restore a displaced bar 15, a cam 30 on the shaft 31 acts on a roller 29 on a rod 27 carried by pivoted arms 25, the rod 27 thus being moved rightwardly to engage a hook 28 on a displaced bar 15 so as to move the bar rightwardly to its latched position.