| 摘要 |
<p>A series of trench support sections (8), each consisting of two vertical walls (81,82) separated by transverse spacers (9,9') are connected in a telescopic arrangement to define an elongate mobile support. The section at the leading end of the support includes a connection point (16) for longitudinal traction along a trench in which the support is located. At least some of the sections are connected to the leading section by longitudinal cables (17,18) for simultaneous traction of the whole telescopic assembly. Horizontal rollers (23) are located at the lower rear end of each section to form a mobile contact with the bottom of the trench. The leading section includes an excavating blade (13-15) at its lower leading edge. <IMAGE></p> |
