| 摘要 |
In a phonograph record player, an improved control mechanism is provided for effecting lead-in movement of a tone arm from an elevated rest position outside the perimeter of a turntable to a selected set-down position on a record supported by the turntable so as to commence a play operation, and for effecting a return movement of the tone arm to its rest position upon the termination of the play operation. In such control mechanism, a main lever is angularly displaced by a cam follower engaging in a cam groove of a control gear to effect the lead-in movement during turning of the control gear from a stop position to a play position, and to effect the return movement during the further turning of the control gear from its play position back to its stop position. In order to prevent inadvertent turning of the control gear from its stop or play position, the cam groove has depressions in its opposite side walls, respectively, disposed adjacent the cam follower in the stop and play positions, respectively, and an additional lever is biased by a spring to urge an edge thereof against a roller on the main lever which engages such edge at different locations, and thereby presses the main lever in opposed directions, when the control gear is in its stop and play positions, for holding the cam follower securely in the depression then adjacent thereto. The additional spring biased lever is rocked upon angular displacement of the main lever to cause a brake to frictionally resist, and thereby stabilize the lead-in and return movements of the tone arm. |
