GB274498A - Tuning device for measuring and control instruments preferably in broad-casting apparatus - Google Patents

Abstract

274,498. Berglin, J., (Assignee of W³nsche, M.). July 16, 1926, [Convention date]. Dials and scales; index hands and pointers.- The actuating-knob and the spindle to be controlled are geared together so that more than one revolution of the knob is required for one revolution of the spindle, an index pointer being displaced so as to read on a different scale for each revolution. The application to a variable condenser is shown, in which three complete revolutions of the knob 11 correspond to a movement of the condenser spindle 3 through 180‹. Housed within the knob 11 is a 6 : 1 reduction gearing comprising a pinion 9 fast with the knob and engaging a spur-wheel 14, fixed to which is a pinion 16 engaging a spur-wheel 5 fixed on the condenser shaft 3. The wheel 14 and pinion 16 are journaled in a plate 12 held stationary by a bracket 17 on the panel engaging a slot 18 in the plate. The plate 12 is slit at 19 so to act as a spring to force the gear-wheels 14, 16, 5, 9 into mesh. Pivoted to the underside of the knob is an indicating pointer 30 having three arms 24, 25, 26 of different lengths which are brought successively into operation after each revolution of the knob by contact with a fixed pin 22 and co-operate respectively with scales A, M, O. An elastic peg 28 prevents rotation of the index 30 through more than 90‹ at a time. The arms 24, 25, 26 may be of different shape or equipped with signs, stamps, luminous colours &c. The invention is applicable to condensers &c. ha,ving a straight line motion, the pinion 5 being geared with the part to be moved in a straight line for instance by means of a rack, endless rope or chain, &c. The pin 22 may alternatively be carried by the knob, the pointer 30 being mounted on the panel.