GB498154A - Improvements relating to the tuning of radio receivers - Google Patents

Abstract

498,154. Adjusting wireless apparatus. COLE, Ltd., E. K., and ROWE, JUN., H. C. Aug. 5, 1937, No. 21566. [Class 37] [Also in Group XL] In a press-button tuning device, the tuning element is moved manually or automatically until arrested by an abutment associated with an actuated press-button and is then locked by the abutment against movement in either direction until depression of another button. Each press button 13 is rigid with a catch rod 2 having notches 9, 10, a depressed button being locked in position by a pivotal locking bar 1 engaging the notch 10 thereof. A cam surface is provided on each catch rod 2 between the notches 9, 10 so that during depression of any button the interlinked locking bars 1 are all rocked to release any previously depressed button which is returned to the outer position by a spring 11. A shaft 14 located inside each catch rod 2 ends in a cranked stud 3 which in the depressed position of the associated button forms the abutment which determines the tuning position of the corresponding station. For fine adjustment of the stud 3, the cover of the button 13 is removed and the shaft 14 rotated by means of the screw head 15, the shaft being threaded into a member 16 at the upper end of the associated rod 2 and locked in its adjusted position by a lock nut (not shown). To tune in a station, after depression of the associated press button, a sliding carriage 4 is moved along guide rods 18, 19, by a manually operated lever 5, Fig. 4, and at the same time the tuning shaft is rotated through a tensioned cord 24, until the operative stud 3, Fig. 2, depresses one of two spring biassed pivotal plates 20, 21 in the carriage 4 and then engages in the slot 23 between these plates to lock the carriage and the tuning shaft in the " tuned in " position. The lever 5 has slight angular play whereby switches are actuated by initial movement of the lever 5 to mute the receiver and disable the automatic frequency control circuit during movement of the tuning shaft. The carriage 4 may, alternatively, be moved electromagnetically through a circuit closed by the depressed press-button or by any other automatic means. For normal timing, a switch 25 is actuated to cut out the automatic frequency control circuit and a cam on the axis thereof causes the locking bars 1 to be rocked away from the catch rods 2 to disable the press-button tuning gear. The switch also extinguishes the illumination of the press-button panel and illuminates the ordinary tuning scale.