Patent GB-446057-A (GB)
Title: Improvements in or relating to printing telegraph receivers
IPC: H04L13/18
Filed: 1935-08-09
Abstract: 446,057. Type - printing telegraphy. CREED & CO., Ltd., Telegraph House, Croydon.-(Assignees of Krum, H. L.; 85, Robsart Road, Kenilworth, and Zenner, W. J. ; Hawthorne Lane, Des Plaines, both in Illinois, U.S.A.) Aug. 9, 1935, No. 22521. Convention date, Nov. 2, 1934. [Class 40 (iii)] [See also Group XVI] A printing-telegraph receiver comprises a device for advancing the medium on which printing is to take place, and an all-mechanical means, effective during the operation of the receiver and during a predetermined cessation thereof, for causing the continuous operation of the medium-advancing device, comprising a pair of elements effective for each character selection and means controlled thereby for controlling the continued actuation of motor-driven means for advancing the medium on which printing is to take place. The tape is led from one reel through the printer and an optical projection system, over a stationary guide, around a guide roller, and between a pair of tape-pulling rollers, and is then rewound on another reel. The tape-pulling and rewind means is mounted on a base 27, Fig. 1. A continuously-rotating motor drives through worm gearing a shaft 24 on which is mounted a pulley 29 connected by means of a slipping belt 31, preferably consisting of a coil spring, to a pulley which is secured to the shaft of the rewind reel 18 for the tape. A cam 28 fixed on the shaft 24 vertically reciprocates, against the action of springs, two pawl members 44, 45 which co-operate to rotate a ratchet-wheel 47 in one direction only. One of the pawl members rotates the wheel on the down stroke, and the other on the up stroke, but to ensure smooth rotation of the wheel, one member begins to rotate the wheel before the other has finished. The ratchet-wheel 47 is mounted on a shaft 61 which has also mounted thereon a knurled roller 63 adapted to co-operate with a spring- pressed roller 68 to pull the tape 10 through the projection system. The pawl members 44, 45 are pressed towards the ratchet-wheel 47 by a common spring 46, but they may be pressed apart so that they cannot rotate the wheel 47, by a pair of toggle levers which are actuated by a plunger secured to one end of a release cable or push wire 83 slidably operable in a conduit 84, Figs. 1 and 9. When the pawl members are pressed apart, a third pawl is automatically engaged with the ratchetwheel 47 to prevent the rotation of the roller 63 by the pull of the reel 18. The other end of the wire 83 is mounted on the printer 12, and is provided with a plunger 176 which is depressed by mechanism governed by codesignalling impulses received by the printer. The printer 12, which is of the type disclosed in Specification 433,503, is of the single magnet selector type employing type-bars, and is mounted on a base 95 on which is also mounted a continuously-rotating motor (not shown), the pinion 96 of which meshes with a worm gear fast on a vertical shaft 104. For controlling the tape-pulling means a cam assembly 113 in addition to the selector-cam assembly 103 is added to the printer. The two cam assemblies act on a link 138 which is adapted to move downwardly upon the cessation of signals to apply pressure to the plunger 176 of the wire 83. The link 138, near the lower end, is pivoted to one end of a bell-crank lever 141 which is provided with a cam follower at the opposite end. When code signals are received by the printer 12, the start signal will permit the rotation of the selector-cam assembly 103 which in turn, through a system of cams and levers, permits the rotation of one cam 131 of the cam assembly 113, which raises the link 138 against spring pressure by means of a lever 134 engaging in a slot therein, to allow the tape-pulling rollers to be rotated. To maintain the link 138 in its uppermost position during the reception of code signals, a second cam 146 in the assembly 113 is provided which is operative in out-ofphase relation with the cam 131 ; otherwise the tape-pulling rollers would be actuated intermittently in timed relation to the movement of the lever 134 by the cam 131. The cam 146 is adapted to engage the cam follower of the bell-crank lever 141 to maintain the link 138 in the upward position for a predetermined definite period. When signals cease, cam 131 stops first, but it is not until cam 146 has stopped that the link 138 is allowed under the action of its spring to depress the plunger 176 of the wire 83 to stop the tapepulling rollers.