| 摘要 |
842,059. Adjusting radio tuning controls. ALADDIN INDUSTRIES Inc. April 22, 1958 [Sept. 26, 1957], No. 12767/58. Class 40(5). A high frequency tuning mechanism comprises a shaft 11 coaxial with a shaft 15 which carries a cam such as 19. The cam follower such as 22 is pivoted as at 21 and engages a spring arm 23 frictionally mounted on the shaft 11 so that rotation of the shaft 15 produces a limited slow rotation of shaft 11. In the embodiment described, fine tuning of a television receiver having separate VHF and UHF tuners is achieved by a common knob 18 attached to the shaft 15. Rotation of the knob 18 controls the VHF fine tuning directly and provides a small adjustment of the UHF tuning via the cam and follower mechanism. The cam follower 22 is coupled to the UHF manual tuning shaft 11 via a spring wire 23 looped around a groove in the shaft 11 at 23a and supported by a compression spring 25. The cam 19 may be replaced by a spiral cam as in Fig. 4 not shown so as to provide a fine tuning over 540‹ rotation of the knob 18. The UHF tuner 13 may comprise a variable capacitor or a resonant cavity. |
