| 摘要 |
An arm is pivotally mounted on a support and movable between a first position at which it is relatively unstable because its center of gravity is above and close to the pivot point and a second position at which it is relatively stable because its center of gravity is well below the pivot point. The lever is mounted so that when in the first position a part thereof is in the path of the movement of the tone arm. As the tone arm contacts that part, it pushes the lever so as to displace the center of gravity across center. Thereafter, as the center of gravity descends the arm picks up the tone arm and holds it against a part of the support. In one embodiment a weight is fixed on an end of the lever. In other embodiments the weight is movable along the length of the lever, with the weight being a solid or a liquid. |
