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AssigneesSouthwire Company, National Steel Corporation
InventorsWinfield M. Hass, Howard E. Niehaus, James L. Pack
Estimating the term…
This disclosure relates to a method of and apparatus for lifting a load utilizing an existing bridge or gantry-type overhead crane in combination with a portable lifting beam or Strongback adapted to be lifted into position and partially supported by the existing bridge crane. The portable lifting beam includes a horizontally extending main beam having a telescoping section to reduce the longitudinal extent of the main beam to a dimension less than the distance between the parallel rails upon which the bridge crane is supported, whereby the lifting beam may be raised and lowered by the bridge crane between the parallel rails while being disposed perpendicular thereto. Once the lifting beam is lifted above the parallel rails, the hydraulic means are actuated to extend the telescoping section from its retracted position to increase the longitudinal extent of the main beam to a dimension equivalent to the distance between the parallel rails whereby the portable lifting beam or Strongback may be disposed thereon. The bridge crane and the Strongback are operable in tandem to lift a load, and include load cell means for correlating the operation of the respective lifting means to the bridge crane and Strongback whereby a load may be apportioned therebetween.
A portable lifting beam for being transported to a worksite and lifted by an existing bridge crane to an operative position spanning two parallel rails, said portable lifting beam that supports a movable lifting means and including a horizontally extending main beam having means at the ends thereof carrying wheels for rollingly supporting said portable lifting beam on said rails, said main beam including a telescoping section, means for controllably retracting said telescoping section to reduce the longitudinal extent of said main beam to a dimension less than the distance between said parallel rails whereby said portable lifting beam may be raised and lowered between said rails while being disposed perpendicular thereto, means for controllably extending said telescoping section from its retracted position to increase the longitudinal extent of said main beam to a dimension equivalent to the distance between said parallel rails for positioning said wheels thereon, and means for locking said telescoping section in its fully extended position.
A method of operatively positioning a longitudinally extensible portable lifting beam in overhead relation to a load, comprising the steps of:
Dependencies are inferred from the claim text.