Patent GB-499702-A (GB)
Title: Printing telegraph apparatus
IPC: H04L17/00
Filed: 1938-04-29
Abstract: 499,702. Type-printing telegraphy. CREED & CO., Ltd. April 29, 1938, No. 12881. Convention date, May 6, 1937. [Class 40 (iii)] [Also in Group XVI] A type-printing receiver comprises a number of stop arms projecting radially from the type wheel shaft and co-operating with selectable stop levers to determine the stop position of the shaft. Transmitter. A number of key levers 13, Fig. 1, selectively position combination bars 17 which tilt corresponding pivoted latch levers 18, Fig. 7, to hold or release contact operating arms 19 for operation by a series of transmitting cams 21 on a driven shaft 22 in a manner described in Specification 376,923. An additional cam on the camshaft 22 operates a common locking bar 23 to hold the latch levers 18 in position during transmission of a signal. Selector mechanism. A motor 25 set in a recessed portion of the frame drives worm 27, Fig. 3, and gear 28 on a vertical shaft 29 which, through friction discs 56, 57, tends to rotate a sleeve 51 bearing a helical series of five projections and a stop arm 63 which, through a bell crank 74, latch 68 and detent 64 is released for one revolution by pressure on a stud 77. The armature 86, Fig. 4, of the receiving magnet 83 being mounted on a lever 79 pivoted at 85 is permitted under the action of a spring 88 to make a clockwise movement on receipt of a no current start signal which movement releases for rotation the sleeve 51 above referred to by pressing the stud 77. The projections 55<1>, Fig. 4, carried by the sleeve 51 successively engage projections 103 on pivoted members 99 moving them in a clockwise direction against the returning action of individual springs 102. Knuckle joints 98 in the members 99 communicate the movement to sword members 94 so bringing their projections 93 against one or other of depending projections 92 carried by the armature member 79 and setting the central arms 94 of the sword members against one or other of two arms of T-members 106 according to the nature of the received impulses. The return springs 102 thus tend to tilt the T-members clockwise or anticlockwise and on the release of transfer mechanism later to be described the combination received is set up in five corresponding code bars 107 by the third arm 105 of the T-members. Transfer release mechanism. An additional cam projection 190, Fig. 3, carried by the sleeve member 51 produces an anticlockwise rotation of an arm 152 rigidly joined to a pivoted detent 44 so releasing the latter from a stop projection 48 of a clutch member 38. This allows the clutch members 38, 39 to engage, so causing rotation of a sleeve member 42 carrying a spacing cam 35, a transfer cam 36 and a printing cam 37. The transfer cam 36 causes angular movement of a Jever 144, Fig. 1, which is communicated through a link 146 to a lever 147, pivoted on a stud 149, which directly releases and replaces the stop member 111, Fig. 4, to allow the code selection tc be transferred to the code bare and then lock them in their selected positions. Type selection. A gear wheel 52, Fig. 1, on the vertical shaft 29 drives, through a gear 53 and friction discs 135, Fig. 5, a type shaft 54 at the end of which is mounted the type wheel, Fig. 8 (not shown), consisting of a thin disc having radial arms carrying the type, and a sleeve having a helically arranged series of radially projecting arms 122. These arms co-operate with a selected drop arm 119, Fig. 2, released by the code bars 107 to determine the position in which the type wheel is stopped. Of the five code bars the centre three 115, Fig. 9, serve to select one of eight selector members 113 associated with the corresponding drop arm 119, Fig. 2. The top code bar 121 has projections half the depth of those in the centre three and when operated in conjunction with these has the effect of allowing the selector members 113 to move to their fullest possible extent or only to half of that distance. By this means the drop arms 119 engage the radial stop arms 122 in two positions and since the stop arms are of stepped form this provides additional stop positions for the type shaft. Lying parallel to and associated with each selector member 113 is a companion member 114, Fig. 9, controlled by the bottom code bar 120. Owing to the presence of abutments on each arm 119 the drop arms corresponding to the members 114 can only move when the drop arms 119 of their associated selector levers 113 are operated but in their lowered position they coact with radial stop arms parallel to but slightly in advance of those associated with their corresponding selector members 113. There are thus thirty-two stop positions for the sleeve 125. The case shift, described later, provides for angular displacement between the type wheel and the stop arm member so providing in all sixty-four positions of the type wheel. In order that the type shaft may not be driven round during the selection of a stop member a detent 154, Fig. 1, mounted together with and operated with the transfer release mechanism 148 is arranged to engage a toothed wheel 153 fixed to the stop arm cylinder during this operation and to release it as soon as the selection is complete. In addition a ratchet wheel 292, Fig. 12, mounted on the type shaft co-operates with a spring-actuated ratchet 294 so as to prevent rebound of the shaft when it is stopped suddenly by a selected stop lever. In a modification of the stop lever mechanism the companion levers are dispensed with and the operative ends of the stop levers 280, Fig. 11, are moved laterally by a comb plate at such times as the lowest code bar of the described machine would be operated. The stop levers are thus moved from alignment with one stop arm 283 to alignment with its associated one 284. In this modification the two associated abutting portions 283, 284 of the stop arms are arranged as two arms of a fork 281 instead of being formed as separate parallel arms. Printing operation. At the end of each revolution of the clutch member 41, Fig. 3, the associated printing cam 37 operates a bell crank 159 pivoted on a vertical spindle 145 to cause movement to the right of a connecting link 161, Fig. 5, which is communicated by a stud 173 to a printing hammer 162 pivoted at its lower end 163. By means of a lug 169 on the hammer and a circular projection 171 on the type wheel boss the movement is further communicated to the type wheel which is slidably but not rotatably carried on the type shaft 54. The head of the hammer 166 effects the actual printing operation in the last part of its movement by pressing the selected type against the platen 172. The backward movement of the type wheel after printing renders the typing visible. Spacing and function operations. Line feed is initiated by the selection of one of the companion members 114 having a depending arm 212, Fig. 1, connected by a horizontal bar 213 to a lever 214 carried on one arm 215 of a fourarmed lever 184 pivoted on the vertical spindle 145 and actuated once per revolution of the spacing cam 35. The movement resulting from the selecting of that particular lever 114 moves the end of the lever 214 to a position adjacent one arm 216, Fig. 3, of a two-armed lever pivoted at 218 the other arm 217 of which is connected to a spacing pawl 219. The movement of the four-armed lever 184 causes the lever 214 to force the arm 216 clockwise and advance the ratchet 221 one tooth which movement is communicated through gearing 224, 225 to the platen 172. Letter spacing. This is effected by an arm 183, Fig. 6, of the four-armed lever 184 which through a pawl 182 pivoted to it advances the carriage 176 one tooth of a rack 181 carried by it, against the action of a return spring attached to it. After each movement the carriage is held by a pawl 188, Case shift. The fourth arm 235, Fig. 1, of the four-armed lever 184 carries two hookshaped members 232, 233, connected by levers 229 to depending arms 227, 228 of two of the companion members 114. When the appropriate one of these is selected by a function signal the corresponding hook-shaped member 232, 233 is moved over the end of one of two members 236, 237 pivoted to a vertical pivoted lever 241 carrying at its upper end a stud 243 coacting with a groove 244 in a collar 245 loosely mounted on the type shaft 54. One of the members having been selected the movement of the four-armed lever 184, by the coaction of one of the members 232, 233 with the appropriate one of the members 236, 237, tilts the lever 241 clockwise or anticlockwise. If in an anticlockwise direction as seen in Fig. 1 the collar 245 is moved to the left and an arm 142 carried by it is forced between the inner inclined surfaces of a projection 141 fixed to the type shaft and a projection 143 carried by the stop arm cylinder against the action of a coil spring tending to hold them together. This provides the necessary relative movement, before referred to, between the cylinder and type wheel to change from the upper to the lower case. The reverse change is brought about by moving the collar 245 backwards by selection of the member 232. Latch members operated in conjunction with the case shift prevent the printing hammer 162 and spacing pawl 182 from operating during the shift. Carriage return. Selection of the appropriate companion member 114 causes the depression of an arm 200, Fig. 7, and, on interaction with a projection 203, the consequent tilting of a frame 204 about. pivots 205, 206. Two arms 207, 208 carried by this frame then withdraw the two pawls 182, 188, Fig. 6, from engagement with the spacing rack 181 allowing the carriage to return to its start position under the action of its return spring. The pawls are prevented from re-engaging the rack until the carriage is fully returned by means of a detent 273 which holds the frame 204 in its actuated position until it is tripped at the completion of the return movement. Paper knife. A taut wire 256, Fig.