GB582528A - Improvements in or relating to alarm devices for indicating failure of the paper feed mechanism in teleprinters - Google Patents

Abstract

582,528. Printing-telegraphs. CREED & CO., Ltd., and SALMON, R. D. March 24, 1944, No. 5506. [Class 100 (iv)] [Also in Group XL] A tape teleprinter comprises tape-feeding mechanism and mechanically-actuated means for closing alarm contacts in the event of failure of proper operation of the feeding mechanism. The tape passes between intermittently-closed gripper jaws 15, 16, around a roller 17 carried by a spring-controlled lever 45 so as to form a loop, over the platen 11 and finally to feedrollers 18, 19. The mechanism is operated from a link 7 forming part of the type-wheel setting- devices as set out in Specification 228,842, [Class 100 (iv)], and moved longitudinally for each setting, first to the right, Fig. 2, then to the left beyond the normal position and finally back to its original position. A lever 26 connected to the link 7 carries a pin 25 which operates another lever 20 upon which the movable jaw 15 is mounted. A pin 29 on the link 7 engages one end of a spring-controlled bell-crank lever 30 at the other end of which is pivoted a pawl 33 against which bears one arm of a three-armed lever 36. Another arm of the lever 36 operates a pawl 39 on the shaft of the feed-roller 19 and the third arm has pivoted to its extremity a lever 42 normally pressed against a pin 44 on the lever 45 by a spring 43. Contacts 53 for operating a local audible or visual alarm and which may open the motor circuit and actuate a key to send an alarm signal to the distant station, are closed when a latch 48 is actuated by a tooth 52 on the lever 42 to release a spring-controlled lever 49 as described below. Normally, as the link 7 first moves to the right, the jaw 15 is opened and the roller 17 draws off a length of tape from the supply roll. At the same time levers 30, 36 rotate clockwise, and the pawl 39 rides freely over one tooth of the ratchet wheel 19. The lever 42 is also moved to the left, Fig. 2, but the pin 44 prevents the tooth 52 from engaging the latch 48 as the feed movement of the roller 17 and lever 45 takes place when the tooth is past the latch. As the link 7 moves to the left, the various levers reverse their movements so that the jaw 15 again grips the tape, and the pawl 39 imparts a feed movement to the roller 19. 'This latter, if the feed is normal, causes the tape to be tensioned and the pin 44 to return to its normal position where it keeps the tooth 52 clear of the latch 48. As the link 7 moves to the right again to its normal position, the various parts return to their original position. If, however, the tape is broken between the jaws 15, 16 and the rollers 18, 19, or the latter rollers fail to feed the tape, the lever 45 is turned by its spring 47 to withdraw the pin 44 from engagement with the lever 42. When this occurs, the tooth 52 engages the latch 48 during the final movement of the link 7 and the lever 49 is released to close the contacts 53. If the motor is not stopped immediately, and a further signal is received, a pin 54 on the lever 26 engages a pin 55 on the lever 49 to restore it to initial position so that the alarm signal will be repeated after the same sequence of operations as before. If the code combination received is one for which feeding of the paper is not required, e.g. for letter shift or the like, a selector bar 56 falls into aligned notches in comb discs. In such position, the bar allows a spring-pressed lever 57 to operate a pivoted bail 59 carrying a rod 61 which is thus raised into the path of the pawl 33 and rotates it counter-clockwise. Thus when the lever 30 is rotated clockwise, the pawl 33 misses the projection 62 on the three-armed lever 36 and no feed takes place. The fixed jaw 16 is mounted on the machine cover 8 and the platen and feed-rollers are mounted on a frame 10 pivoted to the machine frame. Ink - - ribbon mechanism.-The ink - ribbon spools 12, Fig. 1, are mounted on hubs 64, Fig. 7, carrying ratchet-wheels 66 either of which is engaged by a pawl-pin 78 on an arm 67 according to the direction of movement of the ribbon. The arm 67 is pivoted at 68 to a lever 69 oscillated from the lever 30 through the engagement of pins 73, 74, to feed the ribbon. The ribbon feed is reversed when a button on the ribbon engages a forked arm 70 of a lever 71 which engages tongues 75 on the arm 67 to swing the feed pawl out of engagement with one wheel 66 into engagement with the other wheel 66. A detent pawl 76 linked to the arm 67 is swung over at the same time. The mechanism is somewhat similar to that described in Specification 457,821. Specifications 311,684, [Class 100 (iv)1, and 490,368 also are referred to.