Patent GB-504231-A (GB)
Title: Printing telegraph receiver
IPC: H04L17/26
Filed: 1938-05-31
Abstract: 504,231. Type-printing telegraphy. KLEINSCHMIDT, E. E. May 31, 1938, No. 16311. Convention date, June 25, 1937. [Class 40 (iii)] In a type-printing telegraph receiver having a stop wheel, having progressively doubling numbers of stops, associated with a type wheel, the first selective impulse selects a group of characters independent of the rotation of the stop wheel and the rotational control of the stop wheel is determined by the emaining impulses. A driven train of gears 1, 3, 4, Fig. 1, drives, through friction clutches 6, 7 shafts 2, 5. The shaft 2 carries a set of cams 8 and a stop plate 9 coacting with a stop lever 43 pivoted at 44. The receiving magnet 34, when energized, attracts an armature lever 36 pivoted on a stud 37 and carrying a latch plate 38 so coacting with an arm 45 formed integrally with the stop lever 43 that the latter is allowed to turn clockwise under the action of a spring 46 and so to release for rotation the stop plate 9. After one revolution of the cam-shaft 2, the stop lever 43 is reset by means of a lug 48 on the stop plate 9 and a projection 49 on the lever 43. Co-operating with the cams 8 are levers 17, 18, 19, 21, 24 mounted for rotation on a stud 15 and held against a fixed stop 32 by individual springs 31, 33. In the case of the four stop levers 19 and the type-wheel shift lever 21, the holes through which the stud 15 passes are elongated in a vertical direction and they are provided with ledges 51, Fig. 4, which, in the attracted position of the armature 36, co-operate with a fulcrum plate 39, carried by the armature lever 36, in such a way that when depressed by their respective cams they pivot about the plate 39 and so raise their opposite ends. If the magnet 34 is not energized the plate 39 does not come under the ledges 51 and the elongated holes allow the levers to be depressed about their further 'ends without any movement of these ends: The normal stop lever 18 and the four selective stop levers 19 are formed with projections 52, Fig. 9, for co-operation with the stop arms 55 of the stop wheel 54 carried on the frictionally driven shaft 5. The stop wheel has two arms cooperating with the lever 18, two with the first lever 19, four with the second lever 19, eight with the third and sixteen with the fourth. Adjacent each projection 52 on the stop levers is an inclined projection 53 which bears against a horizontal arm of a lever 16 until it comes to rest on top of it, bringing its stop projection 52 in the path of an arm of the stop wheel and releasing any other stop lever which was previously raised. The stop levers 19 are controlled in succession by the second, third, fourth and fifth received impulses, the first impulse controlling the type shift lever 21. If the first impulse is a current condition and the lever 21 is pivoted about the fulcrum plate 39, a stud 22 carried by it turns a lever 23 fixed to a shaft 57 clockwise, so raising an arm 59, Fig. 2, fixed to the shaft and with it a cam projection 61. This moves a lever 62 to the right to a position to be operated by a cam 80 fixed to the shaft 2. The cam 80 forces the lever 62 outwards and, owing to a link device 63, 64, 65, 66 fixed to the frame at 73, the motion is translated to a lateral movement of a shaft 76 carrying a forked arm 77, so sliding the type-wheel 81 to the right a distance equal to the space between the first and second rows of type. At the completion of the revolution of the cam assembly 8, the type-wheel shift is released by the release lever 24 through a latch member 25 pivoted at 26, similar to the member 16. Thus, according to the nature of the first impulse, the first or second row of type is selected and the remaining four impulses determine the amount of angular rotation of the type-wheel. The lower-case type is contained in the third and fourth @ows on the type-wheel and is selected by a special combination of five impulses. This combination stops the shaft 5 in a position such that a projection 111 on a lever 92 pivoted at 86 is allowed to enter a slot 95 in a disc 88, fixed to the shaft 5, and the lever 92 is allowed to follow the contour of a cam 109 on the shaft 2. By means of . a cam projection 110 on the lever 92, the movement forces a lever 75 into engagement with a. case shift cam 89 in which position it is latched on a plate 70. When in engagement with the cam 89, Fig. 2, the lever 75 is forced outwards, the movement being communicated through the links 63, 64, 65, 66 to move the type-wheel axially a distance equal to that between the first and third rows of type. According to the nature of the first impulse of the following signal, the type-wheel may or may not be further moved to the fourth row of type. When a case release signal is received, a projection 94 on a lever 91 similar to the lever 92 releases the lever 75 from the latch plate 70. Stop collars 98, 99, carried on a shaft 97 moved longitudinally with the type-wheel and engaging with drop arms 103, 104 on the function levers 91, 92, prevent these from being, operated when the type-wheel is positioned for printing from the second group. A printing cam 135 fixed on the shaft 2 allows, after the selection of the type, a lever 134, Fig. 3, pivoted at 132, to raise a printing hammer 131 to strike the tape 139 against the type-wheel 81. The tape is stepped forward on the return movement of the hammer by a ratchet wheel 146 and pawl 146. As the hammer rises, a projection 157 on it allows a lever 153, pivoted at 154, to turn anticlockwise bringing a pin 156 into engagement with corresponding holes in the type-wheel to centre this correctly and to hold it rigid during printing. In the positions in which the typewheel corresponds to a case shift position, there is no hole and the lever 153 cannot therefore turn and its lower end engages a projection 158 on the hammer, preventing it from rising. In the position of the type-wheel corresponding to a spacing operation, a depression of half the full depth is formed such that the projection 158, by abutting on a ledge 159, allows the hammer to rise to an extent such that the paper feed pawl, 146 is actuated but not to an extent sufficient for a printing blow. Specifications 473,614 and 499,033 are referred to.