| 摘要 |
<p>An extendible crane boom comprises a number of telescopic boom sections, which are each composed of a tube and a holder mounted at an outer end of the tube and serving as an attachment for a double-acting hydraulic cylinder which serves to displace the individual telescopic boom section out of or into an immediately preceding boom section so as to extend and shorten, respectively, the crane boom in its entirety. The cylinder part (7) of each hydraulic cylinder is connected to the holder via a coupling comprising a screw joint having several screws, and a pair of cooperating male and female members (11, 9), one of which has a part-spherical surface (18) which faces the other and which, when the screw joint is but loosely tightened, allows adjusting the cylinder part into a desired, correct working position in relation to the holder, in which position the screw joint (13) is finally tightened.</p> |
