Abstract: A method and apparatus is disclosed for controlling the angle of a pivoted, pendant supported extensible boom and the mast-boom angle between working positions and a transport position. The structure for controlling the angle includes a wire rope driven by a winch and trained over a boom supporting hoist and over a pendant take-up hoist which includes a floating sheave assembly connected to an extensible portion of the boom by a fixed length pendant. Another fixed length pendant determines the mast-boom angle when the boom is in working position, and a floating sheave stop is pivoted to the mast in position to cradle and/or abut a portion of the floating sheave assembly for enabling complete control of the mast when moved between its transport position and working positions relative to the boom.

Abstract: An apparatus is disclosed for maintaining a predetermined mast-boom working angle of a pendant supported boom substantially constant during extension and retraction of the boom. One embodiment of the invention includes control means connected between the boom and the mast for detecting slight angular changes and actuating power means for paying out or drawing in sufficient pendant to return the mast-boom angle to a predetermined angle. Another embodiment utilizes electrical controls having a first potentiometer capable of detecting linear changes in the effective boom supporting length of the pendant and another potentiometer for detecting linear changes in the length of the boom, said potentiometer sending output signal ratios which vary from a predetermined output signal ratio for actuating power means that takes up or pays out sufficient pendant to return the boom to the predetermined mast-boom working angle and returns the output signal ratio to said predetermined ratio.

Abstract: An apparatus is disclosed for maintaining a predetermined mast-boom working angle of a pendant supported boom substantially constant during extension and retraction of the boom. One embodiment of the invention includes control means connected between the boom and the mast for detecting slight angular changes and actuating power means for paying out or drawing in sufficient pendant to return the mast-boom angle to a predetermined angle. Another embodiment utilizes electrical controls having a first potentiometer capable of detecting linear changes in the effective boom supporting length of the pendant and another potentiometer for detecting linear changes in the length of the boom, said potentiometer sending output signal ratios which vary from a predetermined output signal ratio for actuating power means that takes up or pays out sufficient pendant to return the boom to the predetermined mast-boom working angle and returns the output signal ratio to said predetermined ratio.

Abstract: A method and apparatus is disclosed for controlling the angle of a pivoted, pendant supported extensible boom and the mast-boom angle between working positions and a transport position. The structure for controlling the angle includes a wire rope driven by a winch and trained over a boom supporting hoist and over a pendant take-up hoist which includes a floating sheave assembly connected to an extensible portion of the boom by a fixed length pendant. Another fixed length pendant determines the mast-boom angle when the boom is in working position, and a floating sheave stop is pivoted to the mast in position to cradle and/or abut a portion of the floating sheave assembly for enabling complete control of the mast when moved between its transport position and working positions relative to the boom.

Abstract: A telescopic boom is disclosed having a plurality of generally tubular boom sections each having its corners defined by angled corner plates converging upwardly and inwardly at equal angles relative to a central vertical plane containing the longitudinal axes of all boom sections when properly aligned. Boom shoes secured to the outer surfaces and near the inner ends of the angled corner plates of all boom sections except the largest section slidably engaging the adjacent angled corner plates of the next larger boom section; and similar boom shoes secured to the inner surfaces of the angled corner plates near the outer end of all boom sections except the smallest section slidably engaging the outer angled surfaces of the next smaller section.

Abstract: A crane with a telescopic extensible boom is disclosed. Two cylinders within the boom are each connected between adjacent sections for relative movement between the sections. Pendants are trained over sheaves on a live mast, and one end of the pendants is held by a stop on the mast. The other end of the pendants is received in the boom over sheaves mounted in fixed relation to the respective crane sections. The opposite end of the pendants is connected to the base section of the boom.