| 摘要 |
A shock absorber 10 (Fig. 1) for use submerged in a liquid environment comprises a piston 11, 15 slidable in a cylinder 12 to define an enclosure 18, and aperture means communicating between the enclosure and the liquid environment and providing a passage for environmental liquid. The aperture means may take the form of an orifice 20 in the piston head 15 and a tapered spigot 27 defining the orifice area as a function of piston position. An external compressive load force is resisted by pressurisation of the environmental liquid in the enclosure and the rate at which it can be expelled by the orifice defined by the piston position and the aperture (orifice) area variation with piston position may be chosen to give a desired deceleration characteristics to a load lowered onto the device. The use of environmental liquid means that a reservoir for the liquid is not required and the aperture means which replaces conventional valves results in a simpler and cheaper arrangement which also is not restricted in scale. The aperture means may be formed instead by an apertured cylinder wall the effective cross-sectional area of which aperture also may vary with piston position. <IMAGE> |
