| 摘要 |
A hydraulic support for a mine roof, permitting a series of small collapses is equipped with two pistons 2 and 4 dividing each prop into two unequal parts. The lower part 5 is of approximately constant volume over a fixed period of use. It is filled with viscoelastic matter absorbing energy of impacts and vibrations. The upper part 6 of variable volume by virtue of a small-"bleed" exit is filled with a well known water/oil emulsion as a hydraulic fluid. Parts 5, 6 are separated by the floating piston 4. Thus, a sudden shock conveys pressure to the viscoelastic material, which deforms to prevent damage elsewhere in the equipment, and then regains its shape with consequent loss of liquid from space 6. <IMAGE> |
