| 摘要 |
<p>PROBLEM TO BE SOLVED: To display appropriate auxiliary force to flap doors of various weight by providing a spring constant changing means for changing the spring constant of a nonlinear spring with the spring constant heightened in association with the increase of load. SOLUTION: A compression coil spring 40 is a compression coil spring of unequal pitch. Spaces between element wires 42 are therefore different from each other. In this compression coil spring 40, the relation between load and flexure has a spring characteristic of easy inclination at the beginning. When an adjusting nut 52 is turned clockwise to further compress the compression coil spring 40, the element wires 42 come in contact with each other to reduce effective coil length, and the relation between load and flexure comes to have a spring characteristic of sharp inclination. Accordingly, when a flap door 12 is light, the adjusting nut 52 is loosened to lengthen the effective coil length of the compression coil spring 40, and when the flap door 12 is heavy, the adjusting nut 52 is tightened to shorten the effective coil length of the compression coil spring 40.</p> |
