| 摘要 |
The mobile element (66) is joined to a fixed base plate (14) by a screw (68). The threaded end (69) of this engages in a threaded hole in the mobile element, and adjusts its position. A threaded zone (72) at the other end of the screw, screws into a slide (91) which moves longitudinally. A coupling (73) has a sleeve (78) with two opposite compartments in which two zones (76, 77) of the screw penetrate. Two coil springs (89, 90) are between the base plate and the coupling. The coupling disengages when the pressure on the end of the screw is greater than a predetermined value. |
