| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a ball base assembly which does not change the height of a guide pole in spite of wear of gears. SOLUTION: Both slant faces of the thread ridges of internal threads 8a disposed at a ball base PB and both slant faces of the screw ridges of external threads 27a are brought into pressurized contact with each other so as to bring the front ends of respective pins 28, 29 pressurized at their base ends in a direction perpendicular to the flanks of the shaft of a guide pole into pressurized contact with each other by means of a spring plate 30 fixed to the ball base PB by a screw 31 in regions 5a, 5b at two points on the outside of the region formed with the external threads 27a formed on the outer peripheral surface of part of the shaft 5 of the guide pole GP. Even the slant faces of the screw ridges of both threads 8a, 27a wear, the shaft of the guide pole is not displaced in its axial direction and, therefore, the height of the guide pole does not change and the shaft of the guide pole is merely displaced in a direction orthogonal with the axial direction described above. The height control of the guide pole GP is thereby exactly executed and the operation to correct the bending of the recording traces of a magnetic tape T is eventually correctly executed.</p> |
