GB237926A - Improvements in fine adjustment devices for tuning radio receiving apparatus and the like - Google Patents

Abstract

237,926. Burke, J. P. Aug. 1, 1924, [Convention date]. Wireless tuning-devices, adjustment devices for. -Relates to fine adjustment tuning devices for radio receiving apparatus. The pawl or other support 10 is apertured to receive the shaft 12 of a condenser or other instrument (not shown). The other end of the shaft supports a housing 13 having a scale or like extension 16, movement of the housing causing a corresponding movement of the shaft by means of an actuating intermediary sleeve 19 and set screw 20. A knob 17 is mounted so as to be rotatable relatively to the dial and is secured to a spindle 22 which is journaled in the sleeve 19 and bears a pinion 23 smaller in diameter than the sleeve. The latter is cut away at 24 to permit engagement of the pinion 23 by a gear 25 forming part of a reducing train 25 - - 29, of which 29 is mounted on the sleeve 19 in rotatable and axially slidable relation and carries a cork gasket or friction member 30 for frictionally engaging the panel. A spring 31 acts between the clutch so formed and a collar 32 to urge the gear 29 against the panel, and is compressed when the scale is urged against the panel and held by tightening the screw 20. Direct adjustment of the instrument is made by turning the housing, the gasket sliding over the panel in the following manner:-A friction member such as a spring washer 47 acts between the shaft 12 and spindle 22 as by friction between the sleeve and knob so that the resistance of this washer is magnified through the gear train and transmitted to the gasket 30, causing a sliding contact between it and the panel. For fine adjustment the knob 17 is rotated, causing the clutch gear to be held by the gasket against rotation and an infinitesimal rotation of the shaft 12 to ensue. The clutch gear then forms a fixed abutment about which the adjacent gears revolve and cause rotation of the dial at low speed. A flexible mounting for the gear train comprises arms 36, 37 pivoted at 38, 39 to the dial and having bearings for the supporting pins 40, 41 of the gears. Resilient means such as springs 42, 43 anchored to a pin 44 ensure the necessary interengagement of the train. In this way the gear supports are removed from the congested area about the gear train, looseness or irregularities being taken up and burr prevented.