US Patent 7797850 Contact type measuring instrument

There is provided a contact type measuring instrument in which the contact force of a probe is adjusted by a force created by compressed air and an attraction force between a permanent magnet and a magnetic body. This measuring instrument gives a pulling-in force or a pushing-out force to the probe by controlling a fluid pressure in a probe body. Also, between the permanent magnet attached to the tip end of a movable part of a micrometer attached to the probe body and a plate-shaped member attached to the end part on the side opposite to a contact of the probe, an attraction force according to a distance between the permanent magnet and the plate-shaped member is created.