| 摘要 |
<p>PURPOSE:To specify two positions of a plunger with one coil by containing permanent magnets in a bracket of a magnetic material at its outer shell so that the same polarity poles face with each other, disposing a coil-wound bobbin under the magnet, and providing a yoke and a stopper for specifying the operation of the plunger above and below the plunger passing through the bobbin, thereby inverting the direction of a current. CONSTITUTION:Permanent magnets 2 faced at the same polarity poles are contained in a bracket 1 being magnetic at its outer shell, and a bobbin 4 wound with a coil 4 is arraged under the magnets. A plunger 6 of magnetic material is inserted into a through hole formed by the magnet 2 and the bobbin 4, the top end of the plunger is surrounded by a spacer 8 of a circular disc shape, and a drilling stopper 5 adapted for a conical surface 13 at the lower portion of the plunger is provided on the surface 13. A front yoke 10 having a hole 21 having a diameter smaller than that of the plunger 6 is provided on the spacer 8, and the relationship between the diameter d of the hole 21 and the diameter Do of the plunger 6 is set to 0<=d<D. With the thus construction, the direction of a current flowing through the coil 4 is selected, and the position of the plunger 6 is stopped at the upper or lower position.</p> |
