Rotary crane structure with a selective drive on power unit

A stationary crane assembly comprising;

• a mounting ring supported in a level position on the ground, a frame structure revolvably mounted on said ring about a generally vertical axis and having supporting wheel assemblies to thereby permit rotation of said revolvable frame structure, drive wheels carried by said frame structure and engageable with said ring for revolving said frame around said ring, a power source for said drive wheels;
• a mobile, self-propelled power unit drivable onto said revolvable frame structure and secured thereto for rotation therewith and located over and generally adjacent one side of said ring, said power unit having a source of power and hoist drum means driven by said source of power;
• a boom pivotally mounted to said frame structure adjacent that side of said ring which is diametrically opposite to said mobile power unit, said boom being swingable about a generally horizontal axis between a generally horizontal position and an upwardly extending working position, a mast pivotally mounted on said structure and about a generally horizontal axis and adjacent the point of pivotal mounting of said boom to said structure, said mast being vertically swingable between (1) a generally horizontal position where it can rest above said boom when the latter is in a horizontal position and (2) an upwardly extending working position, back stop means for securing said mast and said boom to said structure when in their working positions, and flexible lines connected between said boom, said mast, and said drum means for raising said mast and boom from their generally horizontal positions to their upright working positions and for permitting said boom to be swung about its generally horizontal pivot point independently of said mast.

A large crane assembly for being stationarily mounted on the ground, said assembly comprising;

• a mounting ring stationarily mounted in a level position on the ground and forming a circular guide track, means for levelling said ring, a revolvable frame structure mounted on said ring and having supporting wheel assemblies for being driven along said guide track to thereby permit rotation of said revolvable frame structure, drive wheels carried by said frame structure and engageable on said track for revolving said frame around said ring, a power source carried by said frame and having a driving connection with said drive wheels;
• a mobile, self-propelled power unit drivable onto said revolvable frame structure and secured thereto for rotation therewith, said power unit secured at generally one side of said ring, said power unit having a source of power and hoist means driven by said source of power;
• a boom pivotally mounted to said frame structure at the side thereof which is diametrically opposite to said mobile power unit and for being swung about a generally horizontal axis between a generally horizontal position and an upwardly extending working position, a mast pivotally mounted on said structure and about a generally horizontal axis and adjacent the point of pivotal mounting of said boom and vertically swingable between a generally horizontal position where it can rest above said boom when the latter is in a horizontal position and an upwardly extending working position, back stop means for securing said mast and said boom when in their working positions, and reeving means connected between said boom, said mast, and said hoist means for raising said mast and boom from their generally horizontal positions to their upright working positions and for permitting said boom to be swung about its generally horizontal pivot point independently of said mast.