US 3,964,001 AGranted

Anti backlash and treadle bar linkage system

AssigneeMotorola, Inc.

InventorAlfred James Clark

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Abstract

In a pushbutton type tuner assembly for a radio receiver the treadle bar drive gear, which is coupled to the manual tuning knob through the crown gear and the clutch mechanism, is biased into meshed relation with the treadle bar gear through a pair of lever arms mounted for pivotable movement about fixed pins, and a pair of springs. With the end of the treadle bar gear shaft supported in an aperture in the side wall of the tuner, the first lever arm applies a moment to the treadle bar shaft through the bias of a spring secured to the front wall of the tuner, thereby holding that shaft tightly against the supporting aperture wall. The second lever arm applies a moment to the pinion gear shaft through the bias of the second spring which couples the two lever arms together and adds to the moment of the first spring. The two moments provide balanced radial forces on the gears which eliminate backlash and maintain the two gears in a properly meshed relation.

Claims9

Dependent claims

A pushbutton type tuner assembly for a radio receiver, the assembly having a supportive structure, a plurality of tuning coils, a plurality of tuning cores, each one of the cores being movable longitudinally within one of the coils, a reciprocatingly movable carriage for holding the cores, and tuning means for predetermining specific positions of the cores within the coils for automatically selecting one of the predetermined positions of the cores and for manually selecting any desired position of the cores, the tuning means comprising:

a gear supporting shaft rotatably mounted on the supportive structure;
first gear means fixedly mounted on the supporting shaft;
manually operable means for rotating the gear supporting shaft;
actuating means rotatably mounted on the supportive structure for moving the core carriage;
second gear means integral with the actuating means and positioned to coact with the first gear means;
first lever means pivotably mounted on the supportive structure and positioned to apply a moment to the gear supporting shaft;
second lever means pivotably mounted on the supportive structure and positioned to apply a moment to the supporting shaft of the actuating means, thereby causing the first gear to mesh with the second gear;
first spring means for biasing the first lever means toward the second lever means;
second spring means connected to the second lever means for biasing the second lever means toward the first lever means.

6 more elements

A pushbutton type tuner assembly for a radio receiver, the assembly having a supportive structure, a plurality of tuning coils, a plurality of tuning cores, each one of the cores being movable longitudinally within one of the coils, a reciprocatingly movable carriage for holding the cores, tuning means for predetermining specific positions of the cores within the coils for automatically selecting one of the predetermined positions of the cores and for manually selecting any desired position of the cores, the tuning means comprising:

a gear supporting shaft rotatably mounted on the supportive structure;
first gear means fixedly mounted on the supporting shaft;
manually operable means for rotating the gear supporting shaft;
actuating means rotatably mounted on the supportive structure for moving the core carriage;
second gear means integral with the actuating means and positioned to coact with the first gear means;
linking means for maintaining the first and second gear means in a meshed relationship and for preventing backlash between the gear means, the linking means including
a first spring means;
first lever means pivotably mounted adjacent one end on the supportive structure and loaded by the first spring means to cause the first lever means to exert force on the gear supporting shaft;
second spring means anchored at a first end;
second lever means mounted to pivot about a portion of the supporting structure, the second lever means having one end spring-loaded by the first spring means and having a second end spring-loaded by a second end of the second spring means, causing the second lever means to exert pressure on the actuating means against the supportive structure.

7 more elements

Dependencies are inferred from the claim text.