| 摘要 |
<p>A support arm may have outlets at the outer end of the arm providing access to compressed air, fume and dust extraction, and electrical power. All utility conduits such as electric welding power supply conductors, air hoses, extraction ducts and electrical control conduits may be encased within the arm to protect them from damage, remove the hazard posed by conduits laying upon the shop floor and to provide for simple access to multiple utilities at a distance from the utility sources. The arm comprises an inner boom (1) pivotally mounted to a stationary supporting structure (4), an outer jib (2), and a knuckle (3) pivotally joining the boom and jib. The boom, jib and knuckle are operable in a horizontal plane to provide access to utility connections at the outer end of the jib within an arc (51-54) defined by the outer extent of the arm. A linkage (62-70) between the boom, knuckle and jib maintains equal angles between the boom, the axis of the knuckle and the jib to avoid uncontrolled movements of the knuckle relative to the boom and jib and to avoid kinking of the flexible conduits connecting from the outer end of the boom, through the knuckle to the inner end of the jib.</p> |
