| 摘要 |
<p>A working volume (15) is formed by first (18) and second (20) members interfitting telescopically. A settable fluid such as concrete is supplied to an inlet (14) from which it is pumped under pressure by a pump (12) into the working volume (15). The pressurised concrete causes the first and second members (18, 20) to extend, which may be used as a ram to raise a structure. The working volume (15) is closed by a valve (19) which contains the concrete under pressure while it sets and cures. The first and second members (18, 20) and the cured concrete therein may be left in position to form part of a construction. The ram may alternatively, or additionally, be used to apply pre-tension to reinforcing members.</p> |
