Scalability and Per-formance of JADE Message Transport System

A concrete placer including a boom supported for pivotal movement on a horizontal pivot axis of a base with powered linkage means for pivoting the boom on the base. The powered linkage means includes a link having one end pivoted on the horizontal axis through a fluid motor interposed between the base and the link. A second fluid ram is pivotally connected to the link and the boom and the powered linkage means is arranged so that the boom can be pivoted about 180 DEG about the horizontal pivot axis.