| 摘要 |
PURPOSE:To operate with a very weak force during change-over for attraction and restoration and obtain sufficiently strong attracting and fixing force by setting so that a force of supporting spring force is balanced for a magnetic attracting force of a permanent magnet which operates for material to be attracted. CONSTITUTION:A magnetic attracting force by a permanent magnet 18 is maximumly working under the condition that the permanent magnet 18, namely yokes 19a, 19b are in contact with material to be attracted 11. A magnetic attracting force is received by a reacting force by the engaging stepped potions 16a, 16b which support a spring 17 and directly works as a contact force to the contact surface between the legs 15a, 15b of frame 15 of the body and the material to be attracted 11. Namely, the frame 15 is attracted to the material to be attracted 11 with a suficient force corresponding to the magnetic attracting force of the permanent magnet 18. However, a force working to the material to be attracted 11 of the permanent magnet 18 itself is offset at this time by the spring 17 and becomes very small. In this case, the permanent magnet 18 can be separated from the material to be attracted 11 with a small operating force by operating a operation bar 20. |
