Abstract:
A lifting frame used for lifting structures by using two cranes. The lifting frame is preferably triangular in cross section and is laterally and diagonally braced. The lifting frame is designed for temporary attachment directly to the structure to be lifted and installed. Crane attachment points are provided at opposite ends of the lifting frame.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention is generally related to the lifting of large objects and more particularly to a frame for lifting a large structure and then installing the structure on a substructure.  
           [0003]    2. General Background  
           [0004]    Lifting large heavy objects is an integral part of every type of construction and is especially important in the marine construction industry. Lifts on the order of twenty-five short tons up to thousands of short tons are commonplace.  
           [0005]    Spreader frames and bars are used extensively to avoid interference between the lifting slings and objects/equipment on the lifted item. Spreader bars and frames are used by a single lifting device to achieve sling clearances and brace lateral loading such that the rigging below the spreader bar or frame can be vertical. A reusable end cap for spreader bars that facilitates simple length adjustments is commonly used.  
           [0006]    The known art of lifting members tends to be two-dimensional, does not necessarily provide optimal spacing for crane connection points, and may require additional bracing in the structure being lifted.  
         SUMMARY OF THE INVENTION  
         [0007]    The invention addresses the above needs. What is provided is a lifting frame that is used for lifting structures by using two cranes. The lifting frame is formed from a three-dimensional lattice frame. The frame is laterally and diagonally braced. The lifting frame is designed for temporary attachment directly to the structure to be lifted and installed in a manner such that the structure does not require additional bracing. Crane attachment points are provided at each end of the lifting frame. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    For a further understanding of the nature and objects of the present invention reference should be made to the following description, taken in conjunction with the accompanying drawings in which like parts are given like reference numerals, and wherein:  
         [0009]    [0009]FIG. 1 is a perspective view of the invention.  
         [0010]    [0010]FIG. 2 is a perspective view of the invention connected to a deck to be installed on a substructure.  
         [0011]    [0011]FIG. 3 is an elevation view that illustrates use of the invention during installation of a deck on a substructure.  
         [0012]    [0012]FIG. 4 is an elevation view that illustrates use of the invention to set the deck on the substructure.  
         [0013]    [0013]FIG. 5 is an elevation view that illustrates removal of the invention after the deck has been set on the substructure.  
         [0014]    [0014]FIG. 6 is a perspective view that illustrates an alternate means of connecting the invention to the deck.  
         [0015]    [0015]FIG. 7 is a perspective view that illustrates another alternate means of connecting the invention to the deck.  
         [0016]    [0016]FIG. 8 is a perspective view that illustrates an alternate means of lifting the invention and deck. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]    Referring to the drawings, it is seen in FIG. 1 that the invention is generally indicated by the numeral  10 . As seen in FIG. 1 lifting frame  10  is a lattice frame that is preferably triangular in shape.  
         [0018]    Two bottom cords  12  are rigidly attached together in a parallel spaced apart arrangement at the same elevation by lateral braces  14 . The bottom cords  12  are rigidly attached to a top cord  16  by a plurality of vertical braces  18  and diagonal braces  20 . The top cord  16  is preferably centered above the top cords  12 . The cords and braces are sized to accommodate the weight of the structure  22  (seen in FIG. 2) to be lifted and installed. As best seen in FIG. 2 the end of each bottom cord  12  provides connecting points  24  for one or more cranes.  
         [0019]    The bottom cords  12  are provided with means  26  temporarily connecting the lifting frame  10  to the structure  22  to accomplish the lift. In the preferred embodiment, this is comprised of a plurality of padeyes  28  and links  30 . The padeyes  30  are rigidly attached to the bottom cords  12 . The links  30  are provided with a bore at each end. Corresponding padeyes  32  are provided on the structure  22  to be lifted and installed. The bores in the padeyes are sized to receive pins for temporarily locking the links  30  to the lifting frame  10  and the structure  22 .  
         [0020]    In operation, slings  34  suspended from crane blocks  36  by two separate cranes  38  are attached to the crane connecting points  24 . The cranes  38  are used to lift the lifting frame  10 . The links  30  are pinned to the bottom cords  12  at the padeyes  28 . The lifting frame  10  is then positioned above the structure  22  so that the links  30  are aligned with the padeyes  32  in the structure  22 . The lifting frame  10  is lowered such that the bores in the links are aligned with the bores in the padeyes  32  in the structure  22 . The links  30  are then temporarily connected (locked) to the structure  22  by inserting pins through the bores. As seen in FIG. 2, the lifting frame  10  may be designed with an overhang section  52  that extends beyond the end of structure  22  to provide clearance between the crane and structure  22 . Although only shown on one end of the lifting frame  10 , the overhand section  52  may be provided on each end. The lifting frame  10  and structure  22  are lifted by the cranes  38  and positioned above the substructure  40  such that the lower stabbing receptacles  42  on structure  22  are aligned with the stabbing posts  44  on substructure  26  as seen in FIG. 3. The structure  26  is lowered onto the substructure  26  to receive the stabbing posts  42  in the lower stabbing receptacles  40  as seen in FIG. 4. The links  30  are then unlocked from the padeyes  32  on the structure  22  and the lifting frame  10  is lifted away from the structure  22  as seen in FIG. 5.  
         [0021]    [0021]FIG. 6 illustrates an alternate means of temporarily connecting the links  30  between the lifting frame  10  and structure  22 . Instead of using padeyes, the links  30  may be welded to the lifting frame  10  and structure  22  as indicated at points  46 .  
         [0022]    [0022]FIG. 7 illustrates an alternate means of temporarily connecting the lifting frame  10  to the structure  22 . Instead of using rigid links  30 , slings  48  are pinned between the padeyes  28  and  32  on the bottom cords  12  and structure  22 .  
         [0023]    [0023]FIG. 8 illustrates an alternate means of accomplishing the lift of the lifting frame  10  and structure  22 . Booms  50  are attached to the bottom cords  12  by the use of padeyes in a manner such as that illustrated in U.S. Pat. No. 6,149,350.  
         [0024]    The invention provides several advantages. The connection points for the cranes are optimally spaced for the lift. This increases the capacity of the lifting equipment. The lifting frame of the invention is connected to the structure at multiple points and the lifting frame is laterally and diagonally braced. This minimizes the bracing required in the structure that is a strict function of the lifting operation and thus reduces the weight and cost of the structure.  
         [0025]    Because many varying and differing embodiments may be made within the scope of the inventive concept herein taught and because many modifications may be made in the embodiment herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.