| 摘要 |
<p>The device has a spring i.e. helical spring, with an end (32) and another end connected to mobile parts (20, 21) e.g. rings, respectively. The spring and the parts are arranged such that turning one of the parts in a rotational direction and the other part in another rotational direction increases the inside diameter of the spring, where the latter direction is opposite to the former direction. The spring and the parts are arranged such that turning the former part in the latter direction or turning the latter part in the former direction decreases the inside diameter of the spring.</p> |
