| 摘要 |
An articulated boom and assembly comprising: (a) a lower boom arm; (b) an upper boom arm foldable over the lower boom arm and pivotal with respect to the lower boom arm; (c) hydraulic cylinders positioned between the boom arms and having piston rods extending therefrom, the hydraulic cylinders with the piston rods, pivotally secured at one end to each boom arm intermediate the boom arm's ends, one hydraulic cylinder being pivotally secured to the underside of the upper arm and the other cylinder pivotally secured to the upper side of the lower arm facing the upper side when the upper arm is folded over the lower arm; (d) a linkage for pivotally connecting the upper arm, lower arm and hydraulic cylinders, the linkage comprising three points of connection, the points when linearly connected forming a triangle with the points of connection forming the apexes of the triangle, with: (i) one apex of the triangle directed towards the hydraulic cylinders and piston rods between the upper and lower boom arms and the linkage being pivotally connected at this point of connection to the free ends of the cylinders or piston rods not connected to the arms; (ii) another apex of the triangle proximate the upper arm being secured to the end of the upper arm proximate this point of connection; and (iii) another apex of the triangle proximate the lower arm being pivotally secured to the end of the lower arm at this point of connection.
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