| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a tension arm capable of making stable tension control by decreasing the hysteresis of a tension spring when a torsion coil spring is used as the tension spring 13 of a tension arm used for a magnetic recording and reproducing device, such as VTR. SOLUTION: The tension spring 13 is so constituted that the distance between the flange 12a of a spring holder 12 holding the tension spring 13 and a pawl part 12b is made larger than the height of the tension spring 13 by assuring spacings between the coils of the torsion coil spring as the tension spring 13, by which even if the tension spring 13 is twisted in a seaming direction and a rewinding direction, there is no loss to be caused by the contact between the respective coils. Since the spring 13 is not compressed by the spring holder 12, the thrust force between the flange 12a and the coils and between the pawl part 12b and the coils is made small and the hysteresis can be decreased.</p> |
