Patent GB-663719-A (GB)
Title: An improved tape feeding device, more particularly for telegraph transmitting apparatus
IPC: H04L17/12
Filed: 1947-07-18
Abstract: 663,719. Telegraph transmitters. TELETYPE CORPORATION. July 18, 1947 [Feb. 7, 1944], No. 19267/47 Class 40 (iii). [Also in Group VIII] In a device for feeding a telegraph signal tape in which tape pins are arranged to engage feedholes in the tape and are given a rectilinear motion to step the tape and are then withdrawn and moved back to a normal position in readiness for the next feeding operation, a member fixed in relation to a reciprocable tapepin carrier has confronting cam surfaces each inclined with respect to a line at right angles to the direction of motion of the tape pin carrier and a reciprocable wedging member engaging the cam surfaces is operated by cams to control the movement of the tape-pin carrier to effect the tape-feeding operation. The mechanism for punching a tape 32 according to the five-unit code and for providing feed perforations by the operation of a keyboard is similar to that described in Specification 531,337. The arrangement for withdrawing the code punch pins 15 by the bail 33, the operation of a member 44 to effect back-spacing of the tape 32 and the operation of the forward-feed pawl 37 by means of the reciprocated punch hammer 19 are as described and shown in Specification 531,337. The code perforations are sensed and the tape 32 advanced by a pivoted unit 12 comprising fingers 76 carrying sensing-pins and a member 77 carrying a number of pins 81 arranged to engage simultaneously successive feed perforations in the tape. A roller 85 carried by an arm 86 co-operates with an inclined surface 96 on the member 77 and an opposed surface 88 on a member 65 fixed in the unit 12. The lever 77 is pivotally connected as shown in Fig. 5, to the arm 115 of a bell-crank 114 operated by a cam 89 on the main transmitting shaft 128 and the arm 86 is connected to an arm 119 of a lever 118 having an arm 121 with a roller 122 in engagement with a further cam 87 on the shaft 128. When contacts 127 are closed the shaft 128 rotates and the arm 86 carrying the roller 85 is moved downwardly so' that by a wedging action between the surfaces 88 and 96 the member 77, carrying the tape-pins 81 in engagement with the tape, is moved to the left. Subsequently the arm 77 is lowered by the action of the cam 87 and the roller 122 so that the pins 81 are withdrawn from the tape. The roller 85 moves downwardly to retain the lever 77 against the adjustable stop 95. Prior to the downward movement of the arm 77, the sensing-fingers 76 move upwardly to engage the code perforations and these serve to retain the tape in the stepped-forward position. To hold the tape in its stepped position in the case in which there are no perforations to be engaged by the sensing pins, two additional pins, moved upwardly at the same time as the sensing pins, press the edge of the tape against a backing- plate. After the downward movement of the member 77, the cam 87 moves lever 86 and pin 85 upwardly so that the member 77 moves to the right under the action of the springs 92 and slightly later the cam 89 operates the bell-crank lever 114 to move the member 77 vertically so that the pins 81 are again in engagement with four consecutive feed perforations in the tape. Signal transmitting apparatus. The sensing- fingers 76 are pivotally connected to bell-crank levers 103 mounted on a shaft 102 and having downwardly extending portions associated with the arms 131 of five gooseneck transmitting levers 134. Projections 138 on the arms 131 engage spirally arranged depressions on the cam sleeve 139 and the contacts 135, 136 are closed by the selective unlatching of the arms 131 by the bell-cranks in accordance with the perforations encountered by the pins on the fingers 76, which are withdrawn from the tape by the clockwise movement of a comb 105 biassed by a spring 113 and formed with a flange secured to a T-shaped lever 108 having an arm 109 associated with a cam (not shown) on the shaft 128. The clockwise movement of the lever 108 is limited by a stop 112. When the rate of keyboard operation exceeds the signal transmission rate, the sensing unit can rotate to a position determined by a stop 151, and if keyboard operation is slowed down or stops, the sensing unit rotates clockwise towards the plates 16, 18 of the punching mechanism until a pin 126 on the side of the sensing unit opens contacts 127 so that the main transmitting shaft 128 is arrested.