Patent GB-167310-A (GB)
Title: Improvements in or relating to telegraph printing systems
IPC: H03M7/40
Filed: 1920-05-13
Abstract: 167,310. Automatic Telephone Manufacturing Co., Ltd., Harrison, H. H., and Smith, S. R. May 13, 1920. Type-printing telegraphs.-In a system of printing telegraphy over a route comprising both air-line and cable, a message is sent over the cable part of the route by means of a single impulse per letter, as for instance in the Hughes system, and means are provided at each end of the cable for transposing the cable signals into signals suitable for land lines, for example Baudot signals, and vice versa. Preferably, apparatus known in connection with five-unit code printing telegraphs is used and a record is made at the same time as the message is retransmitted. Transposing from five-unit code to single-impulse code. In an example, Fig. 1, a constantspeed motor M drives the vertical shaft 1 of the transposing transmitter. Loosely fitted on the shaft 1 are five permutation discs P, D, adapted to be partially rotated by the springs 26, Fig. 2, when the appropriate selector magnets S.M. cause the disengagement of the bar 9 with the notches 5 and afterwards to be restored to normal on the actuation of the re-setting-magnet R.S.M. through the universal bar 10. Corresponding to each of the thirty-one permutations of the discs is a latch L urged towards the discs by a spring LS. The selected latch comes in the path of a roller 19 carried round by the shaft 1, and the bearing 21 is lifted, carrying with it the carriage C with its extension 23 and causing an impulse to be sent to the line L at an instant corresponding to the position of the selected latch, and the type-wheel 4 is arranged to make a permanent record. The latch is restored just before the seting operations by the bucket-shaped member 28, which is depressed against a spring by the roller 26 carried by the shaft 1 riding over the cam 27, and co-operates with the wedge member 30 on the latch. The circuits through the selector magnets may be prepared by a perforated strip and subsequently completed through a contact operated bv a cam on the shaft 1. Two further cams close circuits to operate the feed-magnet and the resetting magnet R.S.M. Transposing from single-impulse to five-unit code. The apparatus is substantially the same as a Hughes receiver in which the type-wheel is replaced by the cams 32-37, Fig. 4, rotating synchronously with the shaft 1 at the transmitter and arranged to prepare in succession, in the thirty-one possible combinations, the circuits of the selector magnets 54-58. Signals are received over the line L by a polarized magnet, the armature of which is raised on the receipt of a signal by the spring 40 and lifts the detent arm 41. The shaft 45 then makes a single rotation, want of synchronism being corrected in known manner by the cam 47 in co-operation with the wheel 48. The contacts 59 are then closed by the cam 60 and the combination of selected magnets is operated corresponding to the position at the moment of the cams 32-26. The contacts 61 then close by the cam 62 and the punch magnet 63 is operated through the contacts 64 closed by the cam 37. Finally the contacts 65 are closed and operate the re-setting magnet 67. Only one signal per revolution is received instead of the theoretical maximum of seven. An arrangement for perforating the tape in accordance with fiveunit signals is shown in Fig. 5. Punches 74 are arranged just out of reach of the punch hammer 68 controlled by the magnet 63. Appropriate punch-selectors 75 are interposed by the magnets 54-58 to cause the hammer to actuate the punches selected, a ratchet-wheel and pawl 71, 73 feeding the tape through the apparatus. The armature 78 of the re-setting-magnet 67 restores the punch selectors 75 to normal.