摘要 |
<p>Two flanged cylinders (2, 3), one of which slides inside the other, are kept selectively in firm contact with each other by the engagement of elastic elements (2) and their terminal tooths with grips (8), the said elastic elements and grips being fixed, respectively, on the outer perimeter of the inner cylinder and the outer perimeter of the outer cylinder, the said engagement being maintained until the traction force applied to the two cylinders exceeds a predetermined value.</p> |