Abstract: A crane with an anti-skewing device comprising a platform suspended under a bridge deck by two end truck assemblies supported by runways on a bridge. Each end truck assembly includes two sets of trolleys and an upper load bar interconnects the two sets of trolleys. A lower load bar is suspended from the upper load bar by a kingpin for rotation about a vertical axis. Hinge tubes support the platform on the suspension assembly for pivotal movement in a direction lengthwise of the platform. Each end truck assembly is driven by a variable speed motor. As skewing occurs a mechanical sensing mechanism senses relative movement between lower load bar and the upper load bar and provides a signal to an electronic circuit causing one or both of the motors associated with the end truck assembly on which the sensing mechanism is mounted to increase or decrease the speed of the motor and thereby correct the skew.

Abstract: 1.