| 摘要 |
<p>Two elements (1, 2; 12, 12'; 101, 102, 201, 202) may occupy various angular positions about at least one pivotal point (11; 18, 19; 111; 211) and are subject to resilient means (3; 13; 103; 203; 229) with two opposite ends (4, 5; 14, 15; 104, 105; 204, 205) each secured to a respective one of the elements on either side of said pivotal point. Said elements are arranged in at least one stable angular position by creating, in the resilient means pivotal movement/stress curve, at least one minimum value (A2/T2) at which the slope of the curve is reversed, said minimum value being created in the immediate vicinity of a maximum value (A1/T1) at which the slope of the curve is reversed, such that the pivotal movement required to go from the minimum value to the maximum value is no greater than 90°.</p> |
