| 摘要 |
<p>A switch having relatively movable contacts, one of the contacts including a support member and an arm pivoted to the support member and engageable with the other contact. The other contact is preferably a roller rotatable about an axis extending across the path of movement between the contacts, the roller being engaged by the pivoted arm when the switch closes. A spring urges the arm toward the roller. The arm and the support member form a looped path for electric current so that magnetic force created by the flow of current urges the arm toward the roller. The relatively movable contacts may be arcing contacts of a switch having main relatively movable contacts.</p> |
