| 摘要 |
<p>The invention relates to a expansible drive core (1), which in its contracted state can be accommodated into a thin-walled tube (2), which has to be driven into the ground, wherein priorto the action of driving the drive core (1) can be expanded as to be clamped against the inner side of the wall of the thin-walled tube (2), and after the action of driving the drive core (1) can be contracted for removal from the tube (2).</p><p>According to the invention the drive core (1) includes a metal core body (3) and at least one expansion means of elastic material (4), such as rubber disposed over this core body (3), and passages (7) are formed in the core body (3), through which a pressurized medium, such as air or water under pressure, can be supplied from the interior of the core body (3) for expanding the elastic expansion means (4), whilst reinforcement means (10) co-operate with the elastic expansion means (4) so as to serve for the transmission of forces between the core body (3) and the thin-walled tube (2).</p> |
