The lifting of heavy loads by use of a crane or other lifting machine is employed in various fields of endeavor, including construction, heavy industries, shipping, and others. Wide loads have always presented the difficulty of lifting the material so that it is relatively level in a desired orientation. Level lifting is required to allow easier positioning of the load material by the crane when the transfer is complete. For example, in the construction industry, it is important when lifting a manufactured wall to do so in a substantially level orientation, so that workers may more easily guide the wall into place as the crane or other lifting machine brings the load down.
One approach to providing relatively level lifting of such wide loads has been the use of a lifting beam, also known in the art as a spreader bar, and referred to herein as a lifting apparatus. A spreader bar is generally a steel beam, preferably an I-beam, having a hoist connector for a crane hook, the hoist connector being best structured so that when the spreader bar is lifted, the beam is held in a relatively horizontal position by the crane. Additionally, the spreader bar will also include load connectors which allow for connecting the spreader bar to a load so that the load hangs below the spreader bar as it is lifted. These load connectors are preferably positioned spread apart on the spreader bar so that the distance between them is adjustable to accommodate loads of various sizes. Typically, the spreader bar includes a series of holes spread apart along the beam. The load connectors are secured at a desired distance spread apart from each other, and are secured in place by a bolt or other fastener which is run through the hole in the spreader bar beam. In addition, the load connectors may have to be repeatedly repositioned during the work day to handle loads of varying sizes. Those skilled in the art will appreciate that this process for adjusting the spread of the load connectors along the spreader bar beam is slow and requires much manual labor.
With the foregoing in mind, the present invention discloses a lifting apparatus, or spreader bar, having load connectors, or load hooks, which are movably mounted along the spreader bar beam so that they can be easily repositioned according to need, and secured in place by tightening a fastener, or by positioning a “stop” along the track. As noted above, prior art spreader bars have a series of holes along their length and require that for repositioning the load hooks be first unbolted from their current position, moved, and then re-bolted into their new location, a procedure that is very time consuming.