| 摘要 |
The cylinder of a dashpot is formed from an accurately dimensioned rigid tube which is received within a soft plastic sheath, the latter surrounding the side walls of the tube and also closing the end of that tube. Integrally formed in the sheath is a specially constructed adjustable valve by means of which the damping action of the dashpot can be controlled. The movable portion of that valve is preferably formed of the same material as the sheath and is received within the sheath with an interference fit, whereby the siding of the valve is substantially insensitive to vibration and to temperature variations. The sheath may overlie the cylinder tube, thereby positively to retain it in position, and may also extend over the open top of the tube, thereby to prevent accidental withdrawal of the piston from the cylinder.
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