Patent GB-524342-A (GB)
Title: Printing telegraph apparatus
IPC: H04L13/18
Filed: 1939-01-27
Abstract: 524,342. Type-printing telegraphs. CREED & CO., Ltd. Jan. 27, 1939, Nos 2895, 2896 and 2897. Convention dates, March, 3, 1938, April 20, 1938, and April 25, 1938. [Class 100 (iv)] [Also in Group XL] In a type-printing telegraph apparatus a type-wheel is, for each printing operation, moved into its printing position and again moved out of that position. Control of the rotational movement of the type-shaft 88, Fig. 1, is by the known method of a sword and T-lever unit 69 under the control of a receiving magnet 68 and a set of cams 67, controlling a set of notched code discs which allow the selection of one of a number of rods 86, the selected one serving to hold an arm 87, attached to the typeshaft 88, in the appropriate position. The transfer of the received combination from the sword levers to the T-levers is controlled by a transfer bail 91 operated by a cam. 119 on a secondary shaft 103. On receipt of a start impulse the cams 67 are released for a single' revolution and at the end of this revolution a cam projection 120 actuates an arm 115, pivoted at 117, to remove a detent 112 from a clutch member 111 on a cam sleeve 113. This member moves into engagement with a driving member 107, this being driven from a power driven gear 106. The consequent rotation of the cam sleeve 113 causes the transfer bail 91, previously referred to, to operate, and, at the end of the revolution a cam 118 actuates an arm 128 to remove a detent 127 from a clutch member 129. On engagement of the latter with its driving member 124 its associated cam sleeve 130 is rotated for a single revolution. Shortly before the transfer cam 119 operates, a cam 125 on the same sleeve 113 raises the type-wheel 144 to the printing position in the following manner. The typewheel is mounted for longitudinal but not rotational movement on the shaft 88 and has formed with it a shouldered bush 266, Fig. 5, the recess 271 of which is held in the upper surface 143 of a frame 139 which is allowed a limited vertical movement by sliding on studs 146 and 142. A spring 137 connects a lower arm 138 of the frame 139 to an arm 134 of a frame 131 pivoted on a'shaft 132 a lower arm of which carries a follower arm 271 co-operating with the cam 125. The cam 125 is such that, at the appropriate instant, it causes counterclockwise movement of the arm 134 with the consequent raising of the frame 139 and type wheel 144. The subsequent lowering of the frame 139 is controlled, not by the cam 125, but by a cam186 on the sleeve 130, which, as it rotates, allows the frame to be lowered slowly. The sleeve 130 also carries a cam 151, Fig. 1, for operating the printing hammer 173 and a cam 202 for effecting operation of any function lever 193 which may have been selected by the incoming signals. The type wheel 144 has two rows of type and the extent to which it is raised determines the case in which printing is performed. The function bars, when selected, are moved clockwise about a pivot 194 and are thereafter moved longitudinally by the cam 202. The two upper function bars 193 control case shift and have projecting lugs 222 which may co-operate with pivoted levers 218, 282 so that according to which bar 193 is selected these levers 218. 282 cause lateral displacement, to one side or the other, of a flat member 207 having a stepped aperture 212. On the elevation of the frame 139 a projection 217 attached thereto abuts against one of two surfaces 213, 214 of the aperture 212, according to the position which it holds, and so limits the elevation of the type wheel to the appropriate extent. A notched pawl 288 on the member 207, by engagement with a fixed stud 209, holds the member 207 in the position into which it was last moved. In order that the fairly strong springs used on the printing and function cam followers may not cause overrunning of the clutch member 129, Fig. 1, a roller type free wheel device is incorporated in the lower end of the sleeve 130 so that if any such overrunning tends to occur the sleeve 130 is locked to the shaft around which it revolves. The typewheel consists of a ring having type pallets which are thrown outwards radially by the hammer for printing.