A device for automatically making and breaking an electric circuit with the commencement and ceasing of speaking currents and similar electric oscillations

摘要

168,300. Telegraphon Ges. Aug. 24, 1920, [Convention date]. Electromagnetic interrupters; contacts; alternating-current relays.-Relates to inertia switches or contacts of the typeemployed for automatically recording telephone messages or other speech. One element of the contact consists of a pivotally-mounted hammer-headed arm M which normally rests against the other contact-part J. The latter is carried on a pivoted armature E ending in a resilient tongue G resting on an adjustable abutment H. Accidental variations in the basic line current cause merely a greater or less flexing of the armature E, G, and this movement is followed by the arm M without breaking contact. When speech currents are superposed, however, the inertia of the hammer contact M is too great to follow the rapid vibrations set up in the armature, and the relay circuit formed by the two points is broken, thereby bringing the record-driving motor into operation. Fig. 2 shows the circuit arrangements of a system for recording telephone messages or the like. Voice currents in the lines 1, 2 are amplified by a valve 6 and, after actuating the recording-needle 8, pass through the winding 10 of a microphone booster 11, 12, to the winding D shown also in Fig. 1. The special contact M controls the current in a polarized relay 15, so that when this circuit is broken by speech currents, the contacts of a time relay 16 are closed. The driving-motor 14 of the recording-cylinder 9 is thereby started and continues so long as speech lasts. In order to adjust the sensitivity of the contact M, the relay is rotatably mounted on a pivot N so that it can be inclined more or less to the horizontal.