Improvements to the devices used to measure the duration of the telephone conversations

摘要

364,952. Counting-apparatus. TELEFONAKTIEBOLAGET L. M. ERICSSON, 33, Kungsgatan, Stockholm.-(Assignees of Olson, A. H. ; 2, Brunkebergstorg, Stockholm.) March 24, 1931, No. 9024. Convention date, March 29, 1930. [Class 106 (i).] A counter for measuring the duration of telephone calls is zeroized, started, and stopped by manipulation of a knob 5 depression of which rocks a spring-controlled yoke 31 carrying rollers 34 for zeroizing the counting drums 18, 19 by engaging heart cams 37 thereon. The ascent of the yoke also effects (a) the disengagement of the actuating pawls 20, 21 and (b) the release by lugs 44 of an inner yoke 39 carrying the spring detents 40, 41 and a spring contact 42. The counter is actuated at every ten seconds by electric impulses from a master clock, these impulses passing by way of contact springs 9, 10, Fig. 7, (closed by rotation of the knob 5) to a magnet 14 the armature 16 of which carries the actuating pawls. Overthrow of the pawls is prevented by a stop yoke 58 and transfer is of the deep notch type the higher pawl being normally held out of driving engagement by a recessed disc carried by the lower wheel. Signals and alarms. A lamp lights for ten seconds before and after each three-minute period. For this purpose the drum 19 is provided with a contact 43, to engage the spring contact 42 and thus effect electric connection from the positive pole through springs 11, 12 (also closed by the knob 5) to the lamp 46. To prevent this circuit from being closed when the counter is at zero the minute drum 18 carries a lug 57 to open the contacts 42, 43 at such time. A buzzer may also be sounded at ten seconds before and at the end of the three-minute periods by means of a contact 52 adapted to be engaged by the armature 16 at each rocking thereof.