| 摘要 |
<p>PURPOSE:To detect excessive tension without the change of characteristic in a captioned device by providing an elastic body on one side to be expanded and contracted by the change of tape tension and an elastic body on another side to be transformed in accordance with arm displacement after a fixed tension is obtained. CONSTITUTION:An arm 1 equipped with a tape guide roller 3 on one end is provided with a link 13 by the support of a pin 12 on another end, and connected to a bellows 15 equipped with an adjusting screw 16. The operation of the arm 1 given elasticity by a spring 10 is detected by loosening and excessive-tension detection microswitches 6 and 8. Since the bellows 15 is suddenly reduced in its transformation amount against compressive force after it is contracted to some extent, the elasticity of the arm 1 is determined only by the characteristic of the spring 10 within the range of the normal tension given to a tape 22. Only when an excessive tension is given, the compressive force of the bellows 15 is adjusted by the screw 16 to push the switch 8 for giving no influence to the characteristic within the normal range.</p> |
