Patent GB-806431-A (GB)
Title: Improvements in or relating to printing telegraph apparatus
IPC: H04L17/26
Filed: 1954-05-03
Abstract: 806,431. Printing-telegraph receivers. GRIFFITH, R. G. July 5, 1955 [May 3, 1954], No. 12812/54. Class 40 (3). In a type-printing telegraph apparatus in which a type-carrier provided with a number of horizontal rows of type faces is moved both in the vertical and horizontal directions in accordance with the received signals to bring a selected type face into the printing position, the mechanism controlling the vertical movements of the type-carrier is actuated, when a predetermined idle condition is detected, so as to lower the type-carrier to its lowest position, if not already in that position. The signal receiving arrangement operates vanes VI ... V5 controlling bars 1 . . . 5 with pivoted extensions E1 ... E5 sliding longitudinally on a rod 7 of an operating cradle actuated by a cam 11. The extensions E . . . E5 when moved upwardly selectively engage space and mark detents S1 ... S5, M1 ... M5 associated with pawls 21 pivoted at 22 on gear-wheels G1 ... G5 to which they are also attached by springs 23. Each pawl 21 has a lateral extension 20a which is latched by the lip L1 ... L5 on a space detent, S1 ... S5, or engages the top surface of a mark detent M1 ... M5. If an operative space detent is engaged by an extension it is rocked free of the extension 20a and the pawl is moved by its spring 23 to connect the gear-wheel G4 to an associated ratchet R1 ... R5 permanently connected to a constantly rotating shaft 25 until the extension 20a meets the top surface of the mark detent M1 ... M5 and the pawl 21 moves against its spring 23 to disconnect the gear-wheel. The rotation of a gear G1 ... G5 produces equal rotation of an associated crank gear CG1 . . . CG5. The crank arms 32 are connected to bell-cranks 40, 45 . . . 52 connected to arms 41, 44, 50 arranged so that if the half-revolution of CG3 produces one unit of movement, the gears CG4, CG5 produce respectively two and four units. The movement of lever 50 is transferred by a pin 56 to a lever 57 pivoted at 58 and operated by a bell-crank 32 from CG15 so that the half revolution of G15 produces by itself eight units of movement. The aggregated movements due to the selective operation of the gears G3 ... G5 together with G15 determine sixteen different amounts of movement which are transferred to a rack 64 engaging a gear-wheel 70 carrying a gear 72 meshing with a gear 73 on a splined shaft 74 carrying a spiral gear 76 engaging a sector 78 on the splined vertical shaft 79 of the type-carrier 83. The gear-wheels G1, G2 controlling the vertical position of the type-carrier 83 operate crank gears CG1, CG2 of which the arms 32 operate bell-cranks 92, 95 of a linkage so that four separate amounts of movement can be applied via lever 96 and cradle 98 to a rod 100 extending across the platen 105 and engaging the forked end of a rod 101 secured by a pin 103 to the supporting carriage 82 for the type carrier 83. A pivoted cradle 127 biased clockwise by a spring 129 has a pin-and-slot connection with an operating bar 110 mounted in a guide 111 and provided with lower and upper latching projections 116, 119 associated with latching members 113, 117 respectively. When both latches are moved out of engagement, the rod 110 is moved to the right by a spring 112 and the cradle 127 is rocked counterclockwise so that an arm 131 engages the space detents S1, S2 and the gears G1, G2 rotate to the mark position which causes the type-carrier 83 to be lowered to its lowest position, if it were not already in that position. The release of the bar 110 is allowed solely when the cams 140, 147 are in their rest positions, as shown, and when the cam 161 is in its rest position with the end of lever 117 engaging a recess 162 or 163 in the cam 161. The cam 140 rotates during the reception of a signal and the printing cam 147 is in operation for a subsequent period of about 100 ms. The cam 161 which unlocks the type-carrier for its resetting in accordance with the next signal reaches the position at which the lever 117 engages a recess at about 100 ms. after the cam 147 has reached its normal position, so that the simultaneous release of the latch members can only take place after an idle period of at least about 350 ms. during which signals have not been received. Specifications 439,745, 441,090, [both in Group XL], 806,432 and 806,433 are referred to.