| 摘要 |
PURPOSE:To control the degree of projection of a magnetic head to a cylinder in an easy and assured way, by sliding the magnetic head in its radius direction by a desired degree via a unfixed state which varies reversibly its form with the external energy. CONSTITUTION:A piezoelectric element which varies its form in the conducting mode and returns to the original form with release of the conduction and a reversible varying state matter 7 made of a form storing alloy, etc. formed by the change of a crystal structure obtained on the basis of the martensite transformation in accordance with the temperature have deformation by the conduction given in response to the operation of a switch and via a circular terminal 62. With this deformation, a head 21 which is mobile in its radius direction interlocks a mount disk 2 via a guide 22. Thus the degree of projection of the head 21 varies freely to a cylinder. As a result, the projection degree of the head 21 can be controlled easily and assuredly in accordance with the using tape, etc. |
