Patent GB-777208-A (GB)
Title: Printing telegraph receiver
IPC: H04L17/26
Filed: 1955-12-09
Abstract: 777,208. Printing-telegraph receivers. TELETYPE CORPORATION. Dec. 9, 1955 [Dec. 16, 1954], No. 35431/55. Class 40 (3). In a printing-telegraph receiver having a type-wheel axially and rotationally displaceable to select the successive characters to be printed by corresponding axial and rotational positioning devices controlled by a selector mechanism responsive to received telegraph code signals, the positioning devices each include at least one succession of independently rotatable cylindrical members eccentrically mounted on each other so that a cylindrical member is angularly shifted about the axis of the preceding cylindrical member when the latter is rotated, the cylindrical members being selectively rotated by pinions engaging rack bars movable longitudinally under the control of the selector mechanism, and an output lever operatively connected to the final cylindrical member of each succession of cylindrical members, the aggregate rotational motion of which is conveyed as a longitudinal motion to means for imparting a corresponding axial or rotational displacement to the type-wheel. A tape is perforated with the corresponding five-unit code simultaneously with the printing of the received characters. Selector operation.-The settings of push bars 22, Fig. 7, in response to the operation of the armature 21 of the receiving magnet and selector mechanism 23 are transferred via interponents 96 to punch interponents 26 and to rack bails 88 ... 93, Fig. 8, provided with extensions 80 engaging the lower ends of pull bars 77, 79, 57, 58, 59 having rack portions engaging pinions on the cylinder members included in the positioning mechanism, Figs. 3 to 6. The rack bail members 88 ... 93 are moved to the right in response to mark elements so that the crossbar 29 of a bail 29, moved upwardly towards the end of a cycle and shown in its raised position in Fig. 8, raises the corresponding rack bars 77, 79, 58, 59. The fifth rack bar 57 is moved upwardly in response to a space element and is rocked out of engagement with the crossbar 29<SP>1</SP> of the bail 29 in response to a mark element. As shown in Fig. 11, the interponents and rack bails are resiliently linked, an interponent 96 being mounted on a pin 85 on the corresponding bail member 91 and having its slotted lower end held against the shaft 97 by a spring 95. Printing takes place when the bail 29 is at the top of its stroke and the rack bars are moved downwardly by the bail 29 early in the subsequent cycle to return the type-wheel to the home position. Type-wheel positioning mechanism.-The rotational position of the type-wheel 32 is controlled by two eccentric cylinder mechanisms 41, 42 linked by arms 38, 39 to a lever 37 connected to a rack bar 36 engaging a toothed wheel 35 having splined connection with the shaft 33 of the type-wheel 32. The axial position of the type-wheel is controlled by a succsesion of eccentrically mounted cylinders 67, 71, 73 selectively rotated by pinions 64, 74, 76 engaged by the pull bars 77, 78, 79 and having a final output cylinder 73 carrying a yoke 81 moving a rack 82 which through toothed segments 83, 86 and a cylindrical rack 34 effects the axial movement of the type-wheel. The mechanisms 41, 42 are similar, and the former comprises a cylinder 44 carrying a pinion 46 which carries an eccentrically mounted cylinder 48 keyed to a pinion 49 provided with a lever arm 43 connected to the arm 38. The selective operation of the bars 57, 58, 59 provides eight rotatable positions and the bars 61, 62 for the shift operation control rotation of the type-wheel through 180 degrees for selection of lower- and upper-case characters located in separate halves of the cylindrical type-wheel. The independently rotatable eccentrically mounted cylinders of Fig. 6 are arranged to provide a total of five axial positions as the type-wheel has a home position in which the last character printed can be seen, a bar 78 connected to the bail member 29 producing a specified movement 2Y for each cycle.. The other three movements are respectively 2Y + 2X, 2Y + 2Z, 2Y + 2X + 2Z derived from the displacements X, Y, Z of the axis of each of the cylinders relative to the axis of the respective cylinder on which it is mounted. Case shift.-The rotation. of the type-wheel 32 through 180 degrees to select the upper-case or lower-case characters is effected by pull bars 61, 62 which are respectively moved downwardly to rotate the pinion 56 of the mechanism 42 with consequent movement of the levers 39, 37 and rack 36. The rack bails 88 ... 93 are formed with extensions 106 having shoulders 128 and grooves 129 such that when the figure-shift signal is received, a sensing arm 104 moves inwardly to engage an extension 118 of a lever 109 which pivots about its supporting pin 111 and becomes latched in the position shown by engagement of its shoulder 122 with the end of a lever 112 and moves its extension 115 clear of an extension 116 on a shift bail 117 which rotates and moves a loop 105 to the left so that the " figures " shift pull bar 61 is brought into the path of the bail 29 in its downward movement. When the bail 29 had moved upward, the setting of the pull bars in response to the figures-shift signal had rotated the type-wheel two spaces towards the home position in the figures-shift group, and the subsequent downward movement of the bail completes the rotation of the typewheel to the figures group " home " position, and at the same time moves down the pull bar operated by the fourth (marking) element of the figure shift code and also by rotation of the pinion 56 moves the letter-shift pull bar 62 to its upper position. As the fifth element of the figure-shift signal is a mark, the pull bar 57 is not operated. When the letter-shift signal is received, the arm 103 is unblocked and engages extension 123 of the lever 112 unlatching lever 109 which rotates in an anticlockwise direction and rocks shift bail 117 so that the letter-shift bar 62 is moved into the position to be operated by the bail 29 during its downward stroke and complete the rotation of the type wheel to its " letters-home " position. Correcting levers engage notches in a disc on the type-wheel shaft 33 and between the rings of the cylindrical rack 34 to correct the position of the type-wheel before the selected character is printed.