| 摘要 |
A hollow plunger is slidable vertically in a housing that has an open upper end, but its upward travel is limited to a predetermined elevated position, in which the lower end of the plunger body is spaced above the housing's bottom wall that holds a pair of opposed spring contact strips that extend below it to form terminals and that also converge upwardly inside the plunger and have upper ends urged toward engagement with each other. Loosely disposed inside the plunger is a shuttle provided with a cross member extending between the contact strips. The inside of the plunger is formed for supporting the shuttle while the plunger is held in its elevated position by a coil spring encircling the contact strips with the shuttle cross member spreading the upper ends of the contacts apart. After the plunger has been depressed a predetermined distance, it starts to move the shuttle downwardly with it. The inner side of each contact strip is provided with a projection extending from the point of engagement of the strip by the raised cross member downwardly a predetermined distance to hold the contacts apart until the descending cross member slides off the lower ends of the projections.
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