To extend the reach of crane booms having telescopic boom sections, a side stowable jib or boom extension is provided for connection to the nose assembly of the fly section or next adjacent boom section, as disclosed in U.S. Pat. Nos. 3,785,505, dated Jan. 15, 1974; and 4,483,447, dated Nov. 20, 1984.
When moving the boom extension from the stowed position on the side of the telescopic boom, to the operative position, wherein the boom extension extends outwardly in alignment with the longitudinal axis of the boom, the boom extension is pivotally connected to one side of the nose assembly of the boom section and then swung around and connected to the other side of the nose assembly. The connections are made by a plurality of pins extending through aligned holes provided in the cooperating end portions of the boom extension and nose assembly of the fly section.
Due to manufacturing tolerances misalignment may occur between the pin connection holes making it difficult, if not impossible, to insert at least the last pin To facilitate the insertion of the pin by aligning the cooperating holes, crane operators have lowered the nose portion of the boom section and associated partly connected boom extension, so the outer end of the boom extension engages a support stand or the ground, and using the force of the boom extension against the stand or ground and further lowering the boom, the proper alignment of the holes is achieved for insertion of the connecting pin This procedure may be difficult and/or time consuming.
USPTO Backgrounds
USPTO Backgrounds