Patent GB-806432-A (GB)
Title: Improvements relating to type positioning mechanism of telegraph printing apparatus
IPC: H04L17/26
Filed: 1954-05-03
Abstract: 806,432. Printing-telegraph receivers. GRIFFITH, R. G. July 5, 1955 [May 3, 1954], No. 12813/54. Class 40 (3). In a printing-telegraph receiver having a typecarrier bearing a number of rows of type faces constituting a lower case area and an upper case area moved to bring a selected type face into a printing position in accordance with the setting of a number of permutation members in response to a received signal and in which case-shift mechanism is provided to shift the type-carrier between two positions in which the lower and upper case areas are respectively operative, the shift of the type-carrier from the upper case area to the lower case area occurs during the cycle of recording in response to the letter-shift whilst the shift from the lower case area to the upper case area takes place during the recording cycle subsequent to that of the figure-shift signal. The arrangement for positioning the type-carrier 83 relative to a printing hammer 234 is identical with that described in Specification 806,431, the bars 3, 4 and 5 in conjunction with bars 1, 2 determining respectively the rotational and vertical movements to bring the selected type face of the lower case group opposite the hammer. The character from the upper case group comprising the thirty-two type faces to the left of the dotted line in Fig. 1, is selected by the positioning corresponding to the selective operation of the bars 1 ... 5 together with the operation of the case-shift bar 15 which through extension E15 and its appropriate detent S15 or M15 operates gears G15. CG15 and links 32, 60 to move the rack 64 so that the type-carrier is rotated horizontally through eight character spaces. In response to the letter-shift signal, the type location l on the type-wheel is brought opposite the printing position, whilst the figureshift signal combination as such brings the location f to the operative position. If the shift mechanism were allowed to operate during the cycle of the reception of the figure-shift signal, the type-space f would be brought to the printing position. After the vanes V1 ... V5 have been set according to the code elements of a signal, a pivoted cradle 8 operated by a cam 11 operates selectively the space detents S1 ... S5 or mark detents M1 ... M5 to control the aggregate-section mechanism to position the typecarrier, the upper or lower case being determined by the position of the bar 15 and extension E15. The code combinations for the letter-shift and figure-shift signals position the type faces l and f 1 opposite the printing hammer and the movement of the carrier to the upper case area together with the movement to select the character in the upper case group is effected simultaneously by the bar 15 in its position corresponding to the case shift signal and by the signal combination following the figure-shift signal. As shown, in Fig. 4, the operation of the vanes V1 ... V5 in response to the five marks of the letter-shift signal allows the bar 300 to drop when a cradle 317 is lowered by cam 319 and to take down a bar 303 which is moved to the left when its projection 308 is engaged by a bail 309 operated by a cam 315. A lever 326 is pivoted to the bar 303 and during its leftward movement rocks the vane V15 counterclockwise against the action of a spring 328, this action being effected before the cam 11 operates the cradle 8 to control the type carrier. A latching member 335 with a slotted end 336 locks the vane V15 in its operated position. The operation of the cradle 8 by the cam 11 causes the type-carrier to be moved to the lower case area. The cradle 317 operated by a cam 319 lifts the bar 300 which subsequently raises bar 303 when the latter is moved to the right by its spring 306. When the figure-shift signal is received the selective operation of the vanes V1 ... V5 allows the bar 338 to drop and to lower bar 339 so that its projection 346 is engaged by bail 309. The leftward movement of bar 339 moves a spring-biased interponent 350 to the left so that its extension 352 falls into a notch in front of a shoulder 353 on a detent arm 335<SP>1</SP> of the member 335 latching the vane V15. As the vane V15 is still in its operated, i.e. letter shift, position when the cam 11 operates the cradle 8, the type-carrier is moved to a position f corresponding to the code elements of the figure-shift signal in the lower case group. When the bar 339 moves back, the extension 352 engages the shoulder 353 to rock the member 335 so that the vane V15 returns to its normal position and operates bar 15 so that the movement of the type-carrier to the upper case area and selection of the character in that area are effected simultaneously by the signal following the figure-shift signal. Specifications 439,745, 441,090, [both in Group XL], and 806,433 also are referred to.