Abstract: An improved float pad mounting is disclosed for releasably connecting the float pad to an outrigger lift jack shaft. The lift jack can be activated to move the shaft between a retracted position for outrigger travel and extended positions grounding the float pad for stabilized outrigger support. The float pad has a base of large area and a central hub upstanding from the base. Cooperating hemispherical surfaces are formed between the shaft and the hub which become engaged in the extended positions to transmit the outrigger load to the float pad base. An annular collar surrounds the shaft, and a pin extended through aligned openings in the collar and shaft secures the collar to the shaft at a location slightly above the load transmitting surface. Two closed links are loosely connected to the collar at 180.degree. spacings around the center axis of the shaft, and two lugs are formed on the float pad hub at like 180.degree. spacings around said hub.

Abstract: The overall length of boom assembly can be increased by the use of a pair of boom extension sections. When the boom extension sections are not required, they are supported at storage locations adjacent to one side of a main boom assembly. When the overall length of the main boom assembly is to be increased, a first one of the boom extension sections is pivotally connected with the outer end portion of the main boom assembly and the second boom extension section is pivotally connected with the outer end portion of the first boom extension section. The two boom extension sections are swung outwardly together around the outer end of the main boom assembly. After the first boom extension section has been firmly connected with the outer end portion of the main boom assembly, the second boom extension section is pivoted about the outer end portion of the first boom extension section.

Abstract: An improved apparatus is used on a crane to prevent engagement of a block with the outer end portion of a boom. When the block comes within a predetermined distance of the outer end portion of the boom, a detector assembly provides a danger signal. In response to this danger signal, an audio-visual alarm is activated and all control valves which are actuated to a position to cause the block to come in contact with the boom are moved toward to neutral positions. A linkage between a manually actuatable control lever and a control valve for a particular crane function includes a hydraulic cylinder. This cylinder is normally pressurized to a fully extended position, but when a danger signal is received indicating that the block is too close to the boom, the cylinder is retracted. This shortens the linkage and shifts the control valve to a neutral position.