GB351639A - Improvements in or relating to oscillation generating apparatus - Google Patents

Abstract

351,639. Tuning-fork oscillation generators. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., Marconi House, Strand, London.-(Assignees of Ranger, R. H. ; 574, Parker Street, Newark, New Jersey, and Nelson, C. E. ; 347, 83rd Street, Brooklyn, New York, both in U.S.A.) April 23, 1930, No. 12597. Convention date, May 3, 1929. [Class 35.] Pulsating current of constant frequency suitable for use in synchronizing rotating or vibratory apparatus in facsimile telegraph and television systems is produced in a coil 43 by means of a tuning fork 1 or like vibrator driven at its natural frequency by air projected at predetermined intervals against a disc 9 mounted on one tine of the fork. Air under pressure is supplied through a nozzle 17 to a chamber 19 which is made broadly resonant to the natural frequency of the fork by moving the nozzle 17 in or out of the chamber. The latter communicates through an opening 21 with a second chamber 23 which is made broadly resonant to the same frequency by adjustment of a plunger 31. The outlet from the chamber 23 is partially obstructed by the disc 9 which vibrates with the tine 7, a rubber buffer being provided on the latter if required to prevent the disc from touching the chamber 23. The other tine of the fork vibrates between the poles of a magnetic core 41 energized by a permanent magnet 39 and embraced by the pick-up coil 43. A disc 11 and washers 49 are used to balance the tines of the fork. Specification 285,503, [Class 38 (iii), Electric motor control systems &c.], is referred to.