| 摘要 |
<p>An electrical switch wherein the movable contact is resiliently biassed out of engagement with the fixed contact and is movable into engagement with the fixed contact by a rotatable cam. The cam is rotatable by a manual operating member and there is provided an electromagnetic arrangement for moving the cam in the direction of its rotational axis relative to the moving contact. The cam can be rotated in one direction from a rest position to close the movable contact to the fixed contact and can be rotated in the opposite direction to disengage the movable contact from the fixed contact. The cam is also movable axially by the electromagnetic means without reverse rotation of the operating member so as to permit the movable contact to return to its rest position. The cam carries first and second cam forms each of which is capable upon rotation of the cam, of moving the movable contact to engage its fixed contact. The second cam starts at the finish of the first cam and the co-operation of the cam and the movable contact is such that after movement of the movable contact by the first cam form to engage the fixed contact and then subsequent return of the movable contact to its rest position as a result of axial movement of the cam then further rotation of the cam and the operating member in said one direction results in the movable contacts co-operating with the second cam form.</p> |
