Patent GB-644850-A (GB)
Title: Improvements in or relating to printing telegraph receivers
Inventor: SALMON REGINALD DENNIS
IPC: H04L13/06
Filed: 1947-07-21
Abstract: 644,850. Type-printing telegraphs. CREED & CO., Ltd. July 21, 1947, No. 32301/48. Divided out of 644,772. [Class 100 (iv)] [Also in Group XL (b)] Platen rotation for blanking.-A printing- telegraph receiver comprising a platen carrying paper upon which printing is to take place in page form includes means responsive to a received form feed signal for imparting a succession of line feed rotations to said platen and at the same time moving a seeker member into engagement with the paper for each of said succession of line feed rotations and means responsive to the entrance of the seeker member into a perforation in the paper to suppress any immediately succeeding line-feed operation of the receiver. The paper 10 is carried on the platen 9 driven by a gear-train from a gearwheel 11 mounted on a shaft 12 carrying a ratchet-wheel 13 which is rotated when a pawl 17 carried on a plate 15 is released for engagement with the ratchet by a line-suppressor lever 23. The plate 15 is connected by a rod 56 to a link 53 adjustably secured to a plate 51 rotated by means of arms 42, 43, 44, 47 and a cam 50 on a function cam-shaft normally released for one revolution in response to each received signal. An arm 40 on the shaft 41 carrying the arm 42 is connected by a link 39 to a plate 16 connected by an arm 35 to a frame 28 carrying a tappet 29 in engagement with the suppressor lever 23. When the plate 16 is rocked clockwise by the rotation of the cam 50, the frame 28 is rotated and the suppressor lever 23 follows, but if the line-feed selector lever 4, operated as described in Specification 620,682, is in its unoperated position to the left of that shown in Fig. 2, a projection 57 engages the end of the suppressor lever 23 and arrests its movement before the pawl 17 is allowed to engage with the ratchet 13. When the lever 4 is in its operated position, the suppressor bar 23 is allowed to follow the frame 28 to the full extent of its movement and the pawl 17 engages the ratchet 13 which is driven by the rotation of the plate 15 by the arm 56. The extent of rotation of the gear-wheel 11 is controlled by a projection 64 on lever 61 having a pin 60 engaged by an arm 59 mounted on the shaft 41 and rocked by the cam 50. The gear-wheel is held in position by a jockey roller 65 mounted on a pivoted arm biassed by a spring 66. A second lever 75 has a projection engaged by a second tappet 31 on the frame 28 and has a projection engaged by a second tappet 31 on the frame 28 and has a turned-over portion 74 engaged by a projection 77 on the form-feed function lever 6 when the latter is in its inoperative, i.e. left-hand, position. The operation of the lever 6 removes the projection 77 from engagement with the portion 74 and a projecting finger 67 on the lever 6 allows a pivoted intermediate lever 68 to follow until it is held by a projection 71 on a latch 72. The left-hand portion of lever 75 is forked, one portion being engaged by a latch member 79 which is released by a pin 82 on the plate 15 towards the end of its rotation so that the other portion 82 rocks a lever bringing the seeker 85 into engagement with the paper 10. When the seeker 85 engages a perforation in the paper and the frame 28 is rocked, the lever 75 rotates to a greater extent so that the projection 71 is moved clear of the intermediate lever 68 which moves inward and its projection 86, engaging under a projection 87, supports the lever 23 so that any further line feed is prevented. When the next signal is received the lever 6 is moved to the left and the projecting finger 67 moves the intermediate lever 68 so that the tooth 71 on the latch 72 snaps back into position and the turned-over portion 74 is replaced on the projection 77 of the lever 6. The operation at the transmitter to control the repeated line-feed operation at the receiver may be the repeated operation of the form-feed key or the automatically repeated transmission of the formfeed signal by the operation of the form-feed key. Alternatively, the form-feed signal may be sent only once from the transmitter and the reception of the signal may control means to allow the cam 50 to rotate until automatically stopped by means dependent on the operation of the form-feed function lever 6. Specification 643,153 also is referred to.