Patent GB-199101-A (GB)
Title: Printing telegraph receiver
IPC: H04L17/22
Filed: 1922-03-13
Abstract: 199,101. Western Electric Co., Ltd., (Western Electric Co., Inc.). March 13, 1922. Electric type-wheel machines.-In a printing telegraph receiver, the selecting members for positioning the type-wheel consists or rotatable shafts each arranged by a half revolution thereof to impart a cliaracteristic degree of rotation to the type wheel. A flat printing disc 29, Fig. 7, the periphery of which is divided by means of radial slots into reeds carrying type, is attached to a wheel 28 which is rotated by means of a rack 25 and pinion 26 through a system of levers attached to a series of discs 13 - 18 on rotatable shafts. The whole of the mechanical selecting mechanism is driven by a motor tending to rotates a shaft 78, Fig. 2. The invention is described in connection with a system using combinations of five selecting units preceded by an additional starting unit. Current or no current on the line causes energization of coils 32, 31, Fig. 4, respectively. On the initial opening of the line prior to the selecting impulses the armature 33 is moved to the left and moves an operating bar 66 to which is pivoted a member 65 which rotates a stop member 63 about a shaft 64. This releases a. finger 61 attached to a shaft 56 and allows the shaft to revolve. This shaft is driven by gearing 58, 59, Fig. 2, from shaft 78, a friction clutch being associated with the gear wheel 58. Keyed to the shaft 56 is a disc 93 in which selecting rods 38 - - 42 are free to slide horizontally. The ends of the selecting rods are bent as shown in Fig. 4, and are guided by the bevelled end 34 of the armature extension 33 to the left or right of a semicircular plate 43, which is midway between guide plates 36, 37. On a back plate 67 are mounted members to which are pivoted five pairs of latches 70, 73. Cams 44 - - 48, Fig. 2, are attached to the respective selecting rods, and if a selecting rod is moved to the right, on further rotation of the shaft 56 its cam actuates a latch 70 and if to the left a latch 73. Latches 75, Fig. 4, are mounted on shafts 74, 79, 80, 81, 82, 83, Fig. 2, and the rest against either the latches 70 or 73. On each shaft is mounted a gear wheel 77 with a disc of wood 84 on each side of it, constituting a friction clutch. The motor tends to rotate all these gear wheels and when a latch 75 is released by movement of either the latch 70 or the latch 73, whichever it is resting against, the corresponding shaft rotates through 180 and with it one of the discs 13 - - 18 to which levers are connected for positioning the type wheel. Hammer-impression arrangements; letterspacing mechanism. - In each selection at least one of the selecting rods 38 - - 42 is moved to the left, and a cam on the rod moves a latch 73 which rotates a lever 131, Fig. 4, fixed to a shaft 130. To the end of this shaft is fixed a cam release latch 132. Fig. 3, which is normally in engagement with a projection 133 forming part of a cam 94, and with this cam is incorporated a fricticn clutch so that on movement of the latch 132 the cam 94 rotates. Co-operating with the cam 94 is a lever 95 pivoted on a shaft 98 and to which is attached a spring-actuated member 96. When the cam 94 rotates the lever 95 is moved into the depression 104, Fig. 9, the shaft 98 is turned and with it a lever 111. Attached to this lever is a striker bar 112 carrying a member 115, Fig. 10, and a member 113. Upon the wheel 28 are teeth of varying depths, the teeth opposite each character being of the same width and depth. When the member 115 is moved in the direction of the arrow, Fig. 10, it engages the teeth on the wheel 28 to correct any slight degree of displacement. Its extreme end engages the reed carrying the type and presses this upon the type 3, through an ink ribbon 4. Case-shift mechanism.-In response to a particular series of selecting impulses all the selecting rods but the one carrying the cam 46 are moved to the left. Fixed to each cam except 46 is a circular plate 51, Fig. 12. Positioned below the plates 51 and having a notch cut in one end thereof are bars 52, 55 slidably horizontally. All these bars are consequently moved to the left and only in this case the uppermost bar 55 catches a bellcrank lever 92, Fig. 15, pivoted to the disc 93 on the shaft 56. This bell-crank lever catches a projection on the cam 88 on the rod 40 and causes it to rotate latch 90 on its pivot, and so release the latch 75 of the shaft 79 and allow this shaft to revolve until the latch 75 strikes the latch 89. The disc 18 on shaft 79 is thus rotated through 180 causing the type wheel to be turned to the portion printing special characters. The printing of a numeral is then carried out in the same way as the printing of a letter. Certain teeth on the wheel 28 are cut so that when member 115 engages with them it cannot move further to print a character and the pawl 117 cannot engage the next tooth of the wheel 116 to advance the, tape. In response to another particular impulse the rods 52, 55 are again moved to the left, and also the rod carrying cam 46. This rod also carries the cam 88 which will on being moved by bell-crank lever 92 engage the latch 89 and allow the disc 18 to be turned through a further 180. Letter-spacing mechanism.-The tape 3 moves between two pairs of finely toothed wheels 121, 122, Fig. 2, above, and a like pair of wheels beneath, on the shaft 120, on which shaft is also a ratchet wheel 116. The member 113 carries a pawl 117, Fig. 10, which on the forward movement engages a tooth of the ratchet wheel 116 and on the complete backward movement the wheel 116 is advanced one tooth. Just before-the finger 61, Fig. 4, has completed a cycle it engages a projecting portion 62 of the stop member 63 and restores it to normal to arrest the finger 61. To accomplish tape movement without printing the type-wheel is rotated until one of the shallower cut teeth is opposite the member 115, Fig. 10, when printing is prevented by the shoulder on this member engaging a shallow depression in the tcoth. The member 113 is, however, moved a distance sufficient to enable pawl 117 to engage the next tooth of the ratchet-wheel 116.