GB334839A - Improvements in automatic telephone systems - Google Patents

Abstract

334,839. Zoller, E., and Villiger, J. May 9, 1929. Automatic transmitters.-In automatic telephone systems, impulses representing the number of the calling party are sent to a wanted sub-station by a transmitter comprising a spring drum 26, Figs. 1, 4 and 6, which carries contact-operating pins and is wound up through a train of gearing connected to the usual dial transmitter, by which additional code messages may be transmitted. The dial 15 carries a spur wheel 16 geared to a spur wheel 17 which is fixed on the shaft 18 of the sender and carries a pawl engaging a ratchet wheel 20 loose on the shaft and adapted to be held bv a pawl 21. Two spring drums 25, 26 are loosely mounted on a sleeve 22 fixed to the ratchet 20, the drum 26 having groups of pins 62 representing the called subscriber's number and adapted to operate additional impuke springs 61, Fig. 1. The drums 25, 26 respectively are normally locked by pins 33, 50 engaging with levers 31, 49 independently mounted on the shaft 32. When the dial 15 is set by rotation in the direction of arrow a, a cam 29 on shaft 18 releases the holding lever 31. of drum 25 and the springs of the drum are tensioned by rotation of sleeve 22 and ratchet 20 which is held when the dial is released. Drum 25, although released during setting of the dial for further digits is prevented from rotating by frictional engagement at 53 with a gear wheel 35 which is driven in the reverse direction by gearing 93, 94, 37, the wheel 37 being fixed to a ratchet wheel 38 which has a lost motion connection with the shaft 18. A disc 39, Figs, and 7, on the shaft 18 moves idly through a small angle until a pin 45 and depression 42 engage an abutment 46 and pawl-lever 41 on a disc 40, after which the ratchet drives the reversing gear. When the dial 15 runs back, the drum 25 tends to turn in the direction of arrow b but further setting movement of the dial keeps it in its normal position. When however, dialling is completed, the drum 25 rotates and by engagement of pin 33 with an inclined face 106 or lever 49 raises the lever and releases pin 50 on drum 26 which then rotates in the same direction as drum 25 until pin 50 meets pin 33 which has been stopped against abutment 97 on lever 49. The lever 49 is connected with the switch hook 7 and is held out of action when the receiver is in place. The drums 25, 26 are controlled by a common governor 102 driven by a ratchet wheel 103 clutched to gear wheels 99, 100 engaging the drums. When the receiver is replaced both drums return to normal.