Patent GB-307960-A (GB)
Title: Improvements relating to telegraph printers
IPC: H04L15/34
Filed: 1927-12-13
Abstract: 307,960. Warburton, F. Dec. 13 1927. Driving-mechanism.-In type-printing telegraphs, particularly for use in systems employing signals of different lengths, a cam-shaft making one revolution per cycle is connected to one of the driven members of a differential gear, and the other driven member is connected to the driving-gear of the typing and selector mechanisms, the arrangement being such that on arrest of the driving-gear the cam-shaft is driven at increased speed to complete the cycle. The driving-mechanism may be employed in apparatus controlled by perforated tape, or in apparatus controlled directly by the signals, and the typing-mechanism may comprise a type-wheel or type-chain. The apparatus described below is tape-controlled and comprises type-chains, for printing two originals, mounted on a carriage associated with letter-spacing and returning-mechanisms, impression being effected on platen rollers associated with line-spacing and blanking-feed mechanisms. In the apparatus shown in Figs. 1 and 2 the driving-shaft A is coupled by pawls 2 to a pinion 3 engaging a pinion 4 on the cam-shaft D. The pinion 3 engages also a pinion 5 on a shaft 6 provided with a bevel-wheel 7 forming part of a differential gear E, the gear casing being geared by pinions 9, 8 to the driving-shaft. The companion bevelwheel 10 is secured to a spindle 11 which is geared to type-carrying chains 54, described below. During the first part of a cycle, the spindle 11 is free and runs at the same speed as the gear casing, the cam-shaft running at the same speed as the driving-shaft. When however type-selection has been effected, the spindle 11 is arrested, and the pinion 5 causes the camshaft to run at double the speed of the driving- shaft, the pawls 2 permitting the pinion 3 to over-run the driving-shaft. To equalize the loads on the spindle 11 and cam-shaft, the camshaft is provided with a cam 42<a> engaging a brake-spring 41<a>. Strip-controlled type-band machines; hammerimpression arrangements; aligning for impression.-The apparatus shown in Figs. 1 and 2 is controlled by a tape 18 perforated in cable code, sliding peckers 12<a>, 12b arranged in two sets of six co-operating with the holes on opposite sides of the centre holes. The peckers engage levers 16 pivoted on separate bell-cranks 24 which are pivoted at 25 and are connected to longitudinally movable combs 26. The levers 16 are connected by springs 15 to a lever 13 actuated by a cam H. When a character is presented, the peckers that register with perforations are moved to the right by the lever 13 and the associated levers 16 are moved into engagememt with a projection 19 on a rod 20. Thereupon a bell-crank 21 operated by a cam G displaces the rod 20 and the combs corresponding to the operative peckers are moved to the left. Pivoted selector-blades 27 are spring- urged towards the combs but are normally retained by a bar 31 carried by a bell-crank 30 engaging a cam L. The selector blades engage arms 32 pivoted on a frame 33 and having noses for engaging stops on the spindle 11, the stops being arranged in two opposite helices 39, 40, and successive stops being approximately 180‹ apart. The frame 33 can rock slightly on a shaft 34 and is connected to a bell-crank 45 which normally restrains a spring-urged arm 47 having a tooth for engaging an aligning-wheel 48 on the spindle 11. When the combs have been displaced, they present a slot to one of the selector-blades and that blade is rocked and the nose on the associated arm 32 engages one of the stops on the spindle. Thereupon the frame 33 is rocked, and the arm 47 being released the tooth thereon engages the wheel 48 and arrests the spindle, printing being then effected in the manner described below. The cam L then restores the displaced selector-blade, and the arm 47 is restored by means of linkage operated by the bar 31. When the combs are restored, the rod 20 is moved forwards and a projector 50 thereon engages projections 51 on the bellcranks 24 and restores the bell-cranks and peckers. The printing-mechanism comprises two sets of types, for printing two originals. carried by two flexible sprocket-chains 54 mounted in a type-carriage P, the chains passing over sprocket-wheels 55, 56 on shafts 53, 95. The shaft 53 is squared and carries a bevel wheel 52 engaging a bevel-wheel 11<b> on the spindle 11. For effecting impression, the shaft 95 is mounted on sliding rods engaging bell-cranks 64 connected by linkage 63, 62, 61 to an arm 59 operated by a cam M. The tape-feed sprocket 85 is connected by a ratchet-device 90 to a pinion 84 engaging a sector 83 on a spindle 78 having an arm 79 connected to a. loose arm 77 by a spring 80 arranged between pins 81, 82. The arm 77 is connected by a link 76 to a blade-spring 75 on a rocking-arm 73 operated by a cam K. A movable stop-plate 72 for determining the feed slides in a block 71 and is connected by a link 88, lever 87, and link 86 to an arm on the spindle 78. Differential movement of the stopplate is determined by a set of six superposed stop-levers 67 each having a finger engaging a slot 70 in one pair of the combs 26 so that successive stop-levers are operated by successive pairs of combs. The stop-plate is initially one space above the top stop-lever. At each operation the combs displace one or more stop-levers, and when the arm 73 is operated the spindle 78 is rocked and the sector 83 turns the pinion 84 idly. the movement being limited by contact of the stop-plate with the first undisplaced stop lever. On return of the arm 73, the arm 77 picks up the arm 79, the pinion 84 drives the sprocket 85. and the tape receives a feed-movement of one space more than the number of spaces in the signal. The type-carriage P is associated with returning-mechanism, described below, and since it is preferred to allow more than one cycle for the return movement, mechanism is provided for preventing operation of the peckers and stop-levers during the movement. The mechanism comprises, as shown in Fig. 2, a bell-crank 67a having a pin 67<c> co-operating with the lever 87, and a rock-shaft 184<a> having an arm 184<d> co-operating with the pecker-actuating lever 16. A link 184, connected to the carriage-returning mechanism, is provided with pins engaging the bell-crank 67<a> and an arm on the shaft 184<a>. When the typecarriage is returned, the link 184 moves to the left so that the arm 184<d> is moved into the path of the levers 16 to prevent operation of the peckers, and the pin 67<c> enters a hole in the lever 87 so as to lock it in the upper position and silence the tape-feeding mechanism. A thumb-piece 184<c> connected by linkage 184<b> to the shaft 184<a> is depressed to prevent operation of the peckers during threading of the tape. The above-described selector-devices may be replaced by rotatable combs and co-operating selector blades which determine the movement of a stop-arm on the shaft 11 and are mounted in a rocking frame adapted to operate the aligning-arm 47. Letter-spacing mechanism; carriage-returning mechanism.-The type-carriage P, Figs. 1 and 2, has a rack 116 engaging a pinion 112 having freewheel connection 114 with an escapement wheel 115 co-operating with a rocking escapement 117 operated by a cam N. The pinion is connected by a friction coupling 109 and bevel-gears 108 to a shaft 107. Fig. 5, which is driven through reversing-gear Q by a shaft 94 geared to a countershaft B. The reversing-gear comprises bevel-gears 98, 99 gearing with a bevel-gear 100 mounted in an axially-movable box Q. The bevel-gear 98 is loose on the shaft 94, and the bevel-gear 99 is secured to a sleeve 105 which is spliced to the shaft 107, both bevel-gears. having clutch-members for engaging a. clutchmember 97 on the shaft 94. Normally the reversing-gear is in the position shown in Fig. 5, and during each cycle the escapement releases and locks the wheel 115 and the type-carriage moves one space. Return of the type-carriage is initiated on presentation of the = or + signal, or is initiated automatically when the type-carriage reaches or approaches line-end position. For these purposes, the box Q engages a bell-crank 119, Figs. 9 and 10, carry-. ing a slide 123 normally out of the path of the finger 122 on a shaft 121 rocked by a cam O. A lever 136 for displacing the slide engages collars 135 on a sliding rod 133, one collar abutting on a fork 141 on a sliding rod 140. Pivoted blades 128, 129, engaging the selector blades 27 corresponding to the + and = signals, engage collars 132. 139 on the rods 133, 140. When the + or = signal is presented, the slide 123 is displaced and the finger 122 rocks the bellcrank 119, the box Q being displaced to reverse the movemsnt of the type-carriage. The box is held in displaced position by a pivoted catch 124, and when the type-carriage reaches the initial position a lug 127 thereon trips the catch, whereupon a spring 104 returns the box to normal position. For initiating return of the type-carriage when it approaches or reaches line-end position, the type-carriage is provided with a projection 142, Fig. 10, for engaging the lever 136, and another projection 143 co-operating with a device controlled by the combs 26. The device comprises (1) an arm 151 pivoted for lateral movement by means of the projection 143 on a rocking arm 154, and (2) an interponent 150 carried by a bell-crank 149 and engaging the lever 136, the bell-crank being connected to a pivoted blade 144 having a finger 145 engaging the two top combs 26, that is the combs that are not moved when the wordspace signal is presented. The projection 143 preferably extends over ten letter-spaces and may be adjustable. If no word-space occurs within ten letter-spaces from line-end, the projection 142 rocks the lever 136 and initiates return of the type-carriage. If however such a word-space occurs, the interponent 150 is positioned between the lever 136 and arm 1