Patent GB-553024-A (GB)
Title: Improvements in or relating to telegraph printers
IPC: H04L17/24
Filed: 1941-08-21
Abstract: 553,024. Type-printing telegraph receivers. INTERNATIONAL BUSINESS MACHINES CORPORATION. Aug. 21, 1941, No. 10686. Convention date, Aug. 24, 1940. [Class 100 (iv)] [Also in Group XL] In a type-printing telegraph receiver in which the typewheel is rotated and moved axially under control of separate combination mechanisms, each movement is controlled by a clutch which is disconnected when engaged by a stop member set by the combination mechanism. The type-wheel may have four rows of characters, sixteen in each row, letters and numerals, &c. being in alternate columns. The first three units of the 5-unit code set combination discs to select one of eight rotary positions of the type-wheel, the last two units set other combination discs to select one of the four rows, and letter and figure shift signals are used, when necessary, to rotate the typewheel one sixteenth of a revolution to bring letters or figures into the printing position. Combination-disc mechanism and positioning of typewheel.-The first three code units may energize one or more of three magnets 51, 52, 53, such as 53, Fig. 5, to rotate one or more of three notched rings 57, so as to align three notches to permit one of eight spring-pressed members 61 to move inwards into the path of a control lever 42 forming part of a clutch arranged centrally with respect to the combination rings. Similarly the last two code units may energize one of two magnets 54, 55, such as 54, to rotate one or both combination rings 71, so as to align two notches to permit one of four members 61 to move into the path of a control lever associated with a second clutch. The control levers allow their shafts to be driven until they are arrested by the members 61 selected by the combination rings. In this way the type-wheel shaft 24a, Fig. 2, is arrested in one of its eight rotary positions and the shaft 23a in one of its four positions. A cam 31 on shaft 23a causes a lever 75 to convert the rotary movement of shaft 23a into an axial movement of the typewheel carrier 50. The shift mechanism by which the type-wheel is rotated one sixteenth of a revolution is described in a later paragraph. A magnet 56, Fig. 5, energized with any one or more of the magnets 53, 54 causes a clutch, similar to that described above but having only one position in which it is arrested, to couple up a main cam shaft 25a, Fig. 4, which rotates more slowly than the shafts 23a, 24a and carries cams which operate the printing hammer, the tape and ink-ribbon feed, and the shift mechanism. Printing hammer and tape feed.-The tape passes between two pairs of rollers, an upper pair 90a, 90b, Figs. 1, 2 and a lower pair 91a, 91b. Each of the upper rollers has a gear 93 meshing with a gear 94 on the shaft 95 which is rotated by a ratchet 99, the pawl 100 of which is carried by a lever 102 oscillated by a cam 34 on the main cam shaft. The lever 102 also moves the hammer 107, Fig. 4, to store power in a spring 108 until a latch engages a notch in the hammer, the hammer being held in cocked position until the latch is released by further movement of the cam shaft. Ink-ribbon feed and automatic reversal.-The main cam shaft 25a also operates through a link 112 and ratchet 128 and pawl 130 to rotate a gear 133, Fig. 15, which rotates five gears 134 clockwise. The gears 134 are carried by a star-wheel 136 engaged by a roller 139 on a lever 137, so as to keep the star-wheel in one or other of its two positions. In the position shown in Fig. 15, one gear 134 engages gear 140 on one of the ribbon take-up drums 142 and feeds the ribbon step by step. When the ribbon is all on that drum, or when the ribbon is arrested for any reason, the gear 140 cannot move on and the gear 134 "walks round " the gear 140, thus tilting the star-wheel 136 until it is moved into its alternate position in which gear 134 disengages gear 140 and one of the other gears 134 engages the gear 145 and drives the other take-up drum 143, thus reversing the feed. Shift mechanism.-The type-wheel 50 is mounted on a sleeve 79a, Fig. 4 also Figs. 8, 9,-(not shown) on shaft 24a so that it can occupy one of two positions, one sixteenth of a revolution apart, being held in either position by a spring-pressed ball. The sleeve 79a is keyed to the shaft 24a so as to rotate therewith. When the type-wheel is positioned, by either shift signal, so that it is in its extreme right-hand position in Fig. 4 and is rotated to one or other of two diametrically-opposite positions, an eccentric member 78 is brought into the path of a lever 81, so that when this is subsequently oscillated by a cam 33 on the main cam shaft, the member 78 moves the typewheel 50 through one sixteenth of a revolution, thereby bringing the other case into printing position.