Patent GB-245149-A (GB)
Title: Improvements in telegraph receivers
IPC: H04L17/22
Filed: 1925-12-23
Abstract: 245,149. Morkrum-Kleinschmidt Corporation, (Assignees of Morton, S., and Krum, H. L.). Dec. 23, 1924, [Convention date]. Type-printing telegraphs.-In a type-printing receiver the received signals control means adapted to determine the setting of each of a group of selectors and subsequently to effect their operation upon the corresponding permutation members, and each selector and each permutation member is arranged to retain its setting until changed in response to a subsequently-received signal. Selector mechanism. The armature 27<1>, Fig. 7, of the signal-receiving magnet 27 is carried by a triangular spring-controlled lever 29 pivoted at 30 and provided with projections 35 for co-operation with arms 36 on the selector members 12 arranged between guide plates 13. One end of each member 12 is pivotally seated on one arm of a corresponding spring-controlled bell-crank 17 of which the other arm co-operates with one of a series of teeth 25 helically arranged on a sleeve 43 mounted loosely on, and driven through a start-stop clutch from, a shaft 21 driven from a motor 24. The other end of each member 12 acts on a corresponding T-lever 37 to set a corresponding slidable segmental permutation member 38 in one or other of its extreme positions. The arrangement is such that the projections 35 can engage the arms 36 to move a member 12 about its pivotal seating only when such member is retracted by the action of the corresponding tooth 25, and the member 12 thus moved, upon its subsequent forward movement, operates the corresponding lever 37. This enables the members 12 to be set or partially set during the operation of printing the character of the preceding selection, and eliminates devices for restoring the members 12 or the members 38. Start-stop mechanism. A radial arm 49, Fig. 10, on the sleeve 43 is engaged by a spring-controlled dog 51 normally held by a latch 55, the dog being pivoted on an arm 52 adjustable about the axis of the sleeve for varying the phase of the action of the teeth 25 on the bell-crank,s 17. During the starting interval the lever 29 is operated by its spring, and through levers 62, 61, Fig. 7, and 60. Fig. 5, operates the latch 55 to release the dog 51. During the final stop interval the arm 49 is again engaged by the dog 51. Printing mechanism. The permutation members 38 are notched to select, in accordance with the group of signals received, one of a series of bars 68, Fig. 12, each controlled by a spring 71 and provided with a rack 67 engaging a toothed segment 66 on a corresponding pivoted type bar 63. The bars 68 are normally prevented from moving to selected position by a striker bar 73 engaging an inclined edge 84 on each bar. The selected type bar is turned on its pivot to print the character on a tape moving in a guide 103 by the action of a cam 76 on a sleeve 87 loose on and adapted to be frictionally clutched to the shaft 21. This cam is engaged by a roller 82 on a lever 81 acting through an adjusting screw 83 on a lever 78 controlled by a spring 79, and the lever 78 imparts an upward sliding movement to a plunger 74 carrying the striker bar 73, which thus allows the selected bar 68 to move into the aligned notches of the members 38, and a shoulder 85 on the selected bar is thereupon engaged by the bar 73 to move the bar 68 upwardly for operation of the type bar. The sleeve 87 carries a gear 88 with a mutilated portion. Fig. 4, normally adjacent to a pinion 89 on a pivoted arm spring-pressed to hold the pinion in engagement with a gear 91 on the shaft 21, and the sleeve is normally maintained in this position by a dog 95 engaging its shoulder 94. The dog 95 is pivoted to a bracket 96 and connected by a spring toggle 97 to the lower arm 98 of a bail 99. At the end of each selection effected by the series of teeth 25, a tooth 102 on the sleeve 43 operates the bail 99 to throw the toggle 97 from its dead-centre position, thus moving the dog 95 to allow the rotation of the sleeve 87 sufficiently to engage gear 88 with the pinion 89, whereupon the cam 76 is rotated through one revolution to effect printing. Letter spacing mechanism. The tape passes between a roller platen 107, Fig. 11, on a shaft 105 and a roller 108 which is under spring pressure and is preferably rotated through gearing 110 from the shaft 105. This shaft is driven through gearing 111, 112 from a shaft 113 provided with a ratchet wheel 116 engaged by feeding and holding pawls 117, 118. The feeding pawl 117 is pivoted to a lever 119 operated from the lever 78. Case-shift mechanism. Each type bar carries two sets of type, and the case shift is effected by the operation of a pivoted bail 124, Fig. 11, to shift the shaft 105, platen frame 104, and rollers 107, 108 axially of the shaft. For this purpose additional bars 68<a> and 68b, selectable like the bars 68 by appropriate combinations of signals, are provided with lugs 130, Fig. 13, each adapted to operate the bail 124 in one direction or the other when the bar 68a or 68b, so selected, is raised by the striker bar 73. During this caseshift operation the lug 130 of the selected bar 68<a> or 68b acts on a bail 133 to lock return movement of the lever 119, thus suppressing the letterspacing movement.