Patent Grant
8955894
Cranes are often used to move heavy loads from one location to another. When more than one load needs to be moved consecutively, a significant amount of time is expended attaching and unattaching the crane's rigging to each load. Furthermore, when using traditional methods to move a load having an off-set center of gravity, several lengths of rigging hardware and multiple cranes are typically required. This multiple-crane technique has several disadvantages. First, it is time consuming to attach (and later unattach) multiple riggings to a load. Second, multiple riggings adds to the overall weight of the load, which in turn requires cranes with relatively higher capacity values. Third, moving the load with multiple cranes requires cranes with relatively longer boom lengths. And finally, using multiple cranes to move a single load is more expensive than if only one of them is needed to do the same job.
One embodiment of the invention is a spreader bar assembly, described in greater detail below, has two longitudinal members connected by a plurality of cross members. A plurality of adjustable support members are capable of being variably attached along the length of the longitudinal members. The support members are attached to support lines that are in turn attached to a load. As compared to traditional riggings, the ability of the support members to be repositioned along the length of the longitudinal members facilitates attachment of a load to a crane, especially when subsequent loads have varying points of attachment. Each support member is preferably repositioned substantially vertically from a load's point of attachment.
In preferred embodiments, one crane is needed to lift a load having an asymmetrical center of gravity because the spreader bar assembly allows the crane's hook to be positioned above the load's center of gravity. Although the spreader bar assembly could also be used with the traditional multiple-crane technique, using a single crane allows for greater mobility for placement of the load.
An embodiment of the invention is a spreader bar assembly. As shown in
In preferred embodiments, the longitudinal members 110 are I-beams, however other elongated rigid structures of various cross-sections may be suitable including tubular members or other extruded shapes. Likewise, cross members 120 preferably have a tubular cross-section, however other rigid structures of various cross-sections may be suitable including I-beams or other extruded shapes. As shown, cross members 120 are preferably engaged to a plurality of longitudinal members 110 such that they are substantially in the same plane. In alternative embodiments, the cross members 120 may be curved substantially within or without the plane of the longitudinal members 110. However, when the ends of cross members engage the longitudinal members, this should be considered substantially in the same plane. Longitudinal members 110 preferably comprise sleeves 160 which engage cross members 120. As a non-limiting example of an alternative embodiment comprising three longitudinal members, cross members may engage just two longitudinal members, or, alternatively, cross members may engage all three longitudinal members.
A support member may be a frame 130 slidably attached to a longitudinal member 110. As shown in
As shown in
In an embodiment, a shackle 300 may be used to attach a support line 140 to a frame 130. A preferable method of moving a load with a crane comprises positioning the spreader bar assembly 110 above a load 400, sliding or otherwise adjustably positioning support members, e.g., frames 130, vertically above the attachment points of the load 400, and attaching the free ends of the support lines 140 to the load 400. The crane hook is preferably positioned vertically above the center of gravity of the load 400. The length of the spreader bar assembly 100 may be different from the load 400. A preferable number of support lines 140 to be attached to a load 400 is at least four and more preferably at least eight or more. In one embodiment support lines 140 are endless slings.
An embodiment of the spreader bar assembly 100 comprises overhead rigging 200 and has longitudinal members 110 comprising rigging attachment members 150. In a preferable embodiment, first ends of rigging lines 220 are attached to the rigging attachment members 150 while the other ends are attached to connectors 210. Rigging lines 220 are preferably wire rope slings. Connectors 210 preferably comprise a plurality of apertures through which shackles 300 may be directly attached. A preferable connector 210 is a tri-link connector. Some shackles 300, in turn, are preferably attached to rigging lines 210 or, alternatively, to lines attached to a crane hook.
Another embodiment is a spreader bar assembly having a longitudinal member and a plurality of adjustable support members variably attached along the length of the longitudinal member.
The embodiments shown in the drawings and described above are exemplary of numerous embodiments that may be made within the scope of the appended claims. It is contemplated that numerous other configurations may be used, and the material of each component may be selected from numerous materials other than those specifically disclosed. In short, it is the applicant's intention that the scope of the patent issuing herefrom will be limited only by the scope of the appended claims.
This application claims the benefit of U.S. Provisional Application Nos. 61/508,953, filed on Jul. 18, 2011, and 61/590,197, filed on Jan. 24, 2012, both of which are hereby incorporated by reference.
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