Patent GB-1207507-A (GB)
Title: Improvements in or relating to teleprinters and the like
Inventor: WILLCOX FREDERICK PRESTON
IPC: B41J21/00
Filed: 1967-09-20
Abstract: 1,207,507. Selective printing. F. P. WILLCOX. 20 Sept., 1967 [21 Sept., 1966], No. 42867/67. Heading B6F. Type-wheel machines; record controlled or electric input signals; printing and perforating machines; compound movement of type-carrier for type selection.-A teleprinter in which the selection of a character is effected on depression of key to generate a seven bit binary code signal applied to a selector 1008, Fig. 10, or by a tape reader 4108 (Fig. 41) or by an external signal applied to the selector 1008 through a serial to parallel converter 4112 (Fig. 41) and which is associated with a perforator, is provided with a type carrier 112, Fig. 2, supporting pivotally mounted type elements 216 which are displaced from an axial resting position to a radial impression position and acted upon by a pivotal hammer 229. The selected type element is presented at the impression position first by rotation of the type carrier cage formed by radially slotted end flanges 204, 206 spaced from one another by a hollow cylinder 202 and then by erection of the type element by a rotary actuator 252 rotated counter-clockwise by a slide 230 through a slot 238 and lip 256 acting on a half-shaft 242 of the actuator 252, whose nose 250, which abuts the end 218 of the type element, rotating the type element 216 counter-clockwise into its erected impression position. Type surface resetting arrangements.-The selected type element 216, Fig. 2, is restored to its rest position in which it is disposed in radial, axially aligned grooves in the flanges 204, 206, respectively, on clockwise rotation of the actuator 252 by a spring 246 on the downward movement of the slide 230, the rotary movement of the actuator 252 being transmitted to the type element 216 by a finger 254. The reset type element is maintained in its rest position by a radial spring washer 220. Aligning for impression; Power assisted type selections.-The type character selecting signal generated by the key or tape reader or derived by an external input signal is applied to the selector 1008, Fig. 10, which is mounted coaxially with shaft 224 carrying the type carrier 112 on a frame 720 of the teleprinter and then transmitted to a drive mechanism 1006 mounted on a frame 708 and driving by way of one or the other pawls 1418, 1418<SP>1</SP>, Fig. 14, a ratchet wheel 1404 mounted on the square shaft 224 to drive the type carrier 112 through the shortest arc in either a clockwise or anticlockwise direction to present the selected type element at the impression position. Pawls 1418, 1418<SP>1</SP> are actuated by respective electromagnets 1422, 1422<SP>1</SP> whose coils are energized at two different levels to index the ratchet wheel at two different speeds depending on the length of arc the type carrier has to traverse. As the ratchet wheel 1404 approaches its final indexing position corresponding to the arrival of the type element at its impression position a magnetic brake 1606 is energized to slow down the rate of indexing. When the type carrier 112 has been indexed to the selected position an electro-magnet 1430 is energized whereupon its pawl 1832 engages the teeth of ratchet wheel 1404 locking the latter and the type carrier in the selected positions.  Combination type selecting mechanism.-The type character signal applied to the selector 1008, Fig. 10, in addition to being applied to the drive mechanism 1006 is also applied in a binary coded manner to electro-magnets 1700 ... 1712 (Fig. 17) each of which, such as an electromagnet 1704, Fig. 18, is associated with a readily inwardly slotted selector disc 1720, said electro-magnets being selectively de-energized to displace the discs 1720 by means of their armatures, such as 1718, into a position defining an axially extending channel which is engaged by one of cantilever mounted rods 1824 associated with the selected type character. The rods 1824 of which there are ninety, one for each type character, are released simultaneously by the armature of an electromagnet which is also de-energized. Concomitantly with the rods 1824, there is released a further set of rods 1832 acted upon by the armature of an electro-magnet 1834 and associated with non-printing functions such as linespacing &c. The rods 1834 contacting in a selective manner one or more of contacts 1836 mounted in a block 1838. The rod 1824, which engages the channel in the selector discs 1720, contacts a commutator 1822, whose segments 1904 ... 1912 determine the direction of rotation of the shaft 214 driven by the pawl and ratchet mechanism 1006, the speed of the drive mechanism 1006 and the angular are through which the shaft 214 is displaced so that the type carrier on the shaft 214 is arrested in the selected type character position. The selector 1008 includes a shaft 1814 which is drivingly associated with the shaft 214. Following the arrestment of the type carrier 112 in the selected position the electro-magnets 1830 and 1834 are re-energized so that their armatures can reset all the rods 1824 and 1832. Hammer impression arrangements.-Concomitantly with the erection of the type elements 216, Fig. 2, by the slide 230, which is actuated upwardly by a jerk cable 260, there is actuated the printing hammer 229, carried by a lever of a bell-crank 228, whose other lever 232 is engaged by the free end of the upwardly displaced slide 230. The hammer 229 is restored by a torsion spring mounted on the pivotal shaft 502 for the bell-crank 228. The jack cable 260, which is guided over rollers 262, Fig. 2, and roller 722 (Fig. 7) is attached at one end to an electro-magnet 716 actuated bellcrank 702 and at its other end to a spring biased piston 726 located slidably in a dash-pot 728. In another embodiment the slide 230 is articulated to a lever 908 (Fig. 9) which is actuated directly by an electro-magnet 902. Letter-spacing arrangements.-The type carriage 112, Fig. 2, is mounted for rotation with the shaft 214 between end frames such as 1002, Fig. 10, of a traversable yoke guided slidably on rods 306, 1004 attached to end frames 708, 720 of the teleprinter. The yoke is attached by means of the end frames 1002 to cables 804, 806 passed around guide rollers 2504, the cables being connected to one another at 2512 Fig. 25 in a housing 2502 supporting rotatably a ratchet wheel 2508 and a drum 2506 fast therewith, the connected cables 804, 806 being attached to a spring which is coiled around the drum 2506. When a selected type character has been imprinted a signal is applied to the letter spacing electromagnet 2524 for its armature 2526 to displace a leaf-spring pawl 2530 and rotate the ratchet wheel 2508 through one tooth space. The ratchet wheel is prevented from rotating in the opposite direction under the bias of the carriage yoke return spring by a back-spacing pawl 2532. Back-spacing arrangements.-To back-space the type-carriage 112, Fig. 2, which is mounted between end frames 1002, of the carriage guiding yoke, a signal is applied to a back-spacing electro-magnet 2542, Fig. 25, whose armature 2534, which supports a pivotal pawl 2532, first rocks a detent plate 2514 to disengage the letter spacing pawl 2530 from the ratchet wheel 2508, then allow the ratchet wheel to move one space back under the bias of the carriage return spring whilst the back-spacing pawl 2532 is in contact with the ratchet wheel and finally allowing the detent pawl 2548, which is in contact with a finger 2546 on the armature 2534, to engage the ratchet wheel 2508. Continued anti-clockwise rotation of the detent plate 2514 disengages the back-spacing pawl 2532 from the ratchet wheel 2508, enabling the latter to complete its back-spacing rotatiou until it abuts the detent pawl 2548. On deenergization of the electro-magnet 2542 the finger 2536 on the detent plate 2514 causes the letter-spacing pawl 2530 to re-engage the ratchet wheel 2508 whilst the detent plate is rotated clockwise, continued rotation into its rest position, in Fig. 25, releasing the backspacing pawl 2532 which re-engages the ratchet wheel to act as a detent, whilst the detent pawl 2548 is disengaged from the ratchet wheel by the finger 2546 on the counter-clockwise rotating armature 2534. Carriage return arrangements.-On receipt of a carriage return signal a carriage return electro-magnet 2560, Fig. 25, is energized to pivot its armature 2520 into engagement with a pin 2518 on the detent plate 2514 to rock the latter anti-clockwise and cause its fingers 2536, 2538 and 2548 to disengage the respective letter and back spacing pawls and tabulating pawls 2530, 2532, 2564 to be disengaged from the ratchet wheel 2508, the detent pawl 2548 being maintained in the disengaged position on account of anti-clockwise pivoting of the back-spacing armature 2534 by the armature 2520 by a leaf spring associated with the armature 2520. Line-spacing arrangements.-Following carriage return or on receipt of a line spacing signal a platen 114, Fig.. 3, fast with a ratchet wheel 2304 is rotated through one or more teeth by energization of an electro-magnet 2312 carried on a pivotal plate 2306 on shaft 2302 and having an armature 2314 whose distal end supports a line spacing pawl 2316 normally disengaged from the ratchet wheel 2304 and pressed into contact therewith by a stop pin 2318 on the pivotal plate 2306. Platen rotation for condensed record work.- The platen is repeatedly line spaced by pulses supplied to the electro-magnet 2312, Fig. 23, until a switch contact 3704 (Fig. 37) sensing a perforation in a record medium contacts the metallic surface of the platen to de-energize the electro-magnet 2312 and discontinue the repeated actuation of the line spacing pawl 2316. See also tabulating arrangements. Fractional line-spacing arrangements.-To print the subscripts or superscripts associated with typed characters the platen 114, Fig. 23, is imparted a partial rotation in either direction by pivoting the rotary plate 23