| 摘要 |
PURPOSE:To make it possible to obtain a small, lightweight and simple structure, by integrally forming a bobbin consisting of a wind-up shaft for holding a magnetic coil and an attraction part for determining the movable range of a permanent magnet. CONSTITUTION:One end of a connection arm 12 comprising a non-magnetic material is fixed to a linear needle 11 and a permanent magnet 13 is fixed to the other end of the connection arm 12 in a state polarized in the axial direction of the needle 11. A symmetric bobbin 17, which has a pair of wind-up shafts 15 arranged on the same line in the axial direction thereof and the notch shaped attraction part 16 positioned between the wind-up shafts 15 integrally formed thereto, is provided and windings 18 are wound around the wind-up shafts 15 and a pair of magnetic coils 19 opposed to a magnetic flux generating direction are formed. The permanent magnet 13 is arranged on the same center line as the magnetic coils 19 so as to be made freely movable in the attraction part 16. Because parts are assembled in the integrally formed bobbin as mentioned above, the assembling of the apparatus becomes easy and magnetic efficiency is enhanced even if a small magnetic coil and a small permanet magnet are used to make it possible to miniaturize the apparatus and to make the same lightweight. |
