| 摘要 |
<p>PCT No. PCT/GB91/01482 Sec. 371 Date Feb. 1, 1994 Sec. 102(e) Date Feb. 1, 1994 PCT Filed Sep. 2, 1991 PCT Pub. No. WO93/05306 PCT Pub. Date Mar. 18, 1993.An annular piston and cylinder device comprises an annular cylinder and a piston therefor, the piston having sidewall portions which extend into the cylinder towards the base thereof in the form of tapering annular webs which together define between them a recess of asymmetrical cross section.</p> |
