Patent GB-501702-A (GB)
Title: Selector mechanism for use in telegraphic printers
IPC: H04L17/18
Filed: 1938-04-14
Abstract: 501,702. Type - printing telegraphy. OLIVETTI & CIA SOC. ANON., C. April 14, 1938, Nos. 11613 and 11614. Convention dates, April 27, 1937 and Aug. 3, 1937. [Class 40 (iii)] A selector mechanism for a type-printing telegraph receiver is characterized by a lever, engaging the armature of the receiving magnet, being acted on by a spring which serves to move it on the first movement of the armature, so starting the operation of the selector mechanism. A frame 1, Fig. 1, on a pivot 2 carries the armature 3 of the line magnet and has at its further end a detent 6. A three-armed lever 9 pivoted on a spindle 10 carries a pivoted pawl 7 held in the raised position by a spring 30 so as to engage the detent 6. One of the lower arms of the lever 9 is connected through a link 11 to the arm 13 of a two-armed lever the second arm 14 of which engages a stop 16 on a plate 17 fixed to a camshaft 18. The second lower arm of the lever 9 is connected by a link 20 to a resetting lever 22 mounted on a pivot 21. On receipt of the start impulse the detent 6 rises, allowing the lever 9 to be moved anticlockwise by a spring 12 connected to the link 11. This removes the detent 14 from the stop 16 and permits rotation of the camshaft anticlockwise. At the end of one revolution a resetting cam 19 on the shaft 18 forces the resetting lever 22 to the left so replacing the detent 14 in the path of the stop 16 and replacing the pawl 7 in engagement with the detent 6, its resilient connection permitting the return movement. The selector mechanism comprises five pivoted levers 35, Fig. 5, mounted on the spindle 10 and tending to be moved anticlockwise by individual springs 36 but normally held by their upper ends being engaged by the common detent 6. Their lower ends are in the form of hook-shaped projections 34 which abut against projections 33 on levers 26 pivoted on a spindle 21. Individual cams 24 helically arranged on the camshaft 18 successively move the corresponding levers 26 to the left, these levers then. tending to be returned by springs 27. If, owing to the nature of a received impulse, the detent 6 remains lowered when a cam 24 actuates its appropriate lever 26, the detent 6 holds the lover 35 against movement and the lever 26 is returned to its initial position by the spring 27. If, however, the detent 6 is raised the lever 26, in its furthest position to the left, allows the lever 35 to move anticlockwise under the influence of the spring 36 in such a way that its, hooked end 34 holds the lever 26 in its displaced position, Fig. 6 (not shown). The impulses are thus registered on the five levers 26 which are then m a position dependent on the nature of each corresponding impulse. Spearheaded extensions 69, Fig. 7, of the levers 26 are now made to engage similar projections 81 on individual coupling members 72, each connected to one of five selector bars 73, by the raising of these coupling members by link mechanism 76, 77, 78 operated by a transfer cam 45. The position of a lever 26 causes its corresponding member 72 to move to the left or right by engagement of the spear-headed surfaces, the members 72 then being lowered again by the link mechanism and retained in the set position by the engagement of projections 74, 82. After this transfer has taken place a further cam 55, Fig. 9, on the shaft 18, causes clockwise movement of a pivoted lever 51 through a lever'53 and link 52 and, by means of a common bar carried by the lever 51, returns the levers 35 to their initial position. In order to compensate for distortion of signals, means may be provided for displacing the five selector cams 24, Fig. 10, relative to the start cam 19. The selector cams 24 are fixedly mounted on the shaft 56 the end of which has a slot in which is slidably mounted a pin carried in a collar 62 and passing through inclined slots 60, 61 in a sleeve 57 carrying the resetting, start and transfer cams 55, 19, 45. When the pin is moved laterally, by means of a pivoted lever 63, loosely engaging the collar 62, the inclination of the slots 60, 61 causes the sleeve 57 to be rotated relative to the shaft 56.