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US 4,251,974 AGranted
Sensing and control apparatus for lifting heavy construction elements
AssigneePeter M. Vanderklaauw
InventorPeter M. Vanderklaauw
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Abstract
The present invention relates to a jacking system for use in the construction of buildings or other structures in which accurate control and synchronization of lifting points is required. The system is mainly used in lift-slab and lift-plate construction with permanent or removable columns and features an arrangement of converging control wires which activate sensing apparatus. The sensing apparatus controls hydraulic pumps placed at each or plural lifting points.
Claims6
A method of controlling the upward motion of heavy building elements by means of converging control wire comprising the steps:
- casting and permitting to harden a plate to be lifted;
- installing a plurality of vertical lifting post assemblies to the upper surface of the cast and hardened plate;
- attaching a lift control wire to the tops of each lifting post assembly;
- lacing each control wire through a pulley attached to the plate adjacent the bottom of each post assembly;
- lacing each wire through a tension monitoring device and through a pulley block;
- electric conductors connecting each monitoring device to electrically operated hydraulic pumps placed at each lifting post assembly;
- causing said control wires to extend in parallel to one edge of the concrete plate;
- attaching a tension weight to each control wire and thereafter attaching the weights together, whereby non-uniform lifting of the cast plate causes the tension in the wires to change and said change is sensed by the monitoring devices.
5 more elements
Dependencies are inferred from the claim text.