Patent GB-1189677-A (GB)
Title: Improvements in or relating to Teleprinters
IPC: B41J19/72
Filed: 1967-06-12
Abstract: 1,189,677. Typewriters and the like. NIPPON ELECTRIC CO. Ltd. 12 June, 1967 [10 June, 1966], No. 27010/67. Heading B6F. In a teleprinter comprising a printing carriage 28 pulled to the left or carriagereturn direction by a spring 1 connected at one end to the carriage 28 and anchored at its other end, mechanism is provided for characterspacing the carriage 28 against the pull of the spring 1, for back-spacing the carriage, and for releasing the carriage for carriage return under the action of spring 1. The carriage 28 is attached to an endless band 29 passing around a sprocket 51 situated at the upper end of a shaft 50 carrying at its lower end a ratchetwheel 2 engageable by a retaining pawl 6, a character-space pawl 5 and a back-space pawl 4. The pawl 6 is pivoted at 35, and the pawls 4, 5 are pivoted at 56 to a lever 9 pivoted at 35, the parts 4, 5, 9 forming a toggle-lever arrangement. The machine includes a codebar-assembly 27 with a print and spacing suppression bar 26, a function-drive bail 12 connected by a spring 49 to a cam-operated drive arm 13, and a cam-oscillated carriagedrive bail 11. A roller 8 on the arm 11 engages the rear edges of the pawls 4, 5, 6 in the rest position. Character spacing.-A projection 36 on the pawl 6 normally engages a shoulder 37 (Fig. 2), on a pivoted latch so that operation of the pawl is prevented. When a print signal is received, the code bar 26 is allowed to move to the left so as to release the latch 14 and the pawl 5. The assembly 4, 5, 9 can now follow the roller 8 as the bail 11 moves rearwardly and pawls 4, 5 slip into the next tooth of ratchet wheel 2 which is engaged by retaining pawl 6. When the roller 8 subsequently moves forwardly, the pawl 5 rotates the wheel 2 one tooth space for character spacing, the pawl 6 slipping into the next tooth. Carriage-return.-If a carriage-return signal is received, a carriage-return function bar 21 is allowed to rise as the bail 12 rises. This blocks leftward movement of the code bar 26, so that the latch 14 remains operative and no character space operation can occur. During subsequent downward movement of the bar 21 as the bail 12 returns to its initial position, the rear end of the bar engages and moves downwardly a member 19 against the action of a spring 38. A projection 39 on the member 19 then moves downwardly a lever 20 which, through parts 15, 16 turns a lever 41. The lever 41 is operatively connected to the end 42 of a lever 3 carrying at its opposite end a plate 43 which engages extensions on the pawls 4, 5, 6, and moves all the pawls away from the ratchet wheel 2 so that the carriage 28 is free to return to its leftward position under the action of spring 1. At its end adjacent to plate 43, the lever 3 has a downward extension which is engaged by a latch 7 to hold the lever in the carriage-return position. Back-spacing.-If a back-spacing signal is received, a back-spacing function bar 25, Figs. 1, 9, is allowed to rise as the bail 12 rises and blocks movement of code bar 26 to suppress character spacing. The rear end of lever 25 engages in a notch in a spring-raised member 23, so that as the lever 25 is subsequently moved downwardly by the bail 12, the member 23 is also moved downwardly. During such movement, a projection 45 on member 23 engages and depresses a lever 24 which lever has a central downward projection which turns a bell-crank lever 18. The bell-crank 28 through parts 51, 17, 15, 16, 41, 42 operates the lever 3 so that end plate 43 engaging extensions on the pawls 4, 5, 6 moves in a direction to separate the pawls from the ratchet wheel 2 as for carriage return. The pawl extensions are staggered, however, so that the retaining pawl 6 and the character-space pawl 5 are released before the back-spacing pawl 4. For back-spacing, the movement of lever 3 and its end plate 43 is restricted so that only pawls 5, 6 are released and pawl 4 is effective to proceed a back-spacing. To this end, as the member 23 moves downwardly its lower edge 52 contacts a roller 22 which causes the member 23 to move rearwardly and release the lever 24 so that movement of the projection 43 ceases before the pawl 4 is disengaged.