Abstract:
The invention is a device that is used to securely hold a crucible for lifting by a lifting device. It has a circular frame with a top bracing leg that ensures straight vertical lifting and proper alignment of the rigging. The frame diameter is slightly larger than the crucible. Vertical pieces extend downward from the top of the frame. At the bottom end of each of these vertical pieces, a hinged piece is attached. On the hinged pieces, a bottom rigging retainer is attached. The bottom rigging retainer allows the rigging to freely pass through it. The bottom rigging retainer with the hinged piece forms a loop through which the rigging is thread. The rigging securely holds the bottom of the crucible. A lifting device is attached to the riggings to lift the crucible. The frame can be made adjustable to fit many sizes of crucibles.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to the field of devices for handling crucibles and more particularly to the field of devices that handles crucibles while they are being lifted in and out of the melting furnace.  
         BACKGROUND OF INVENTION  
         [0002]    Crucibles are expensive, they are made with very thin walls, and the walls become brittle after being in the furnace awhile. Thus, crucibles can be easily broken. In a foundry, one of the most dangerous times in dealing with crucibles is when the crucible is lifted out of the melting furnace. When the crucible is being lifted, it can be easily bumped into the melting furnace wall and break or crack or do damage to the furnace. Further, the heavy weight of the crucible makes it a safety hazard to the individuals lifting it. Thus, one of the objectives of this invention is to create a system that can lift a crucible from the melting furnace safely and without damage to the crucible or furnace. The device is also designed to place a new crucible back in the melting furnace without damaging the crucible and insuring a proper vertical placement.  
           [0003]    In order for the lifter to ensure a safe handling of the crucible without damaging the crucible or allowing the crucible to strike against the furnace, the lifter must ensure a straight vertical lift of the crucible without having the crucible swing or make other potential damaging movements. The lifter must also be able to lift the crucible when there is a minimum clearance between the furnace walls and the crucible of two to three inches. These objectives must also be obtained with a device that is easy to use, inexpensive to build and maintain.  
           [0004]    The features that allow the inventors lifter to achieve his objectives is that the lifter has a fabricated steel assembly that precisely positions, aligns, and engages and holds in place flexible rigging around the base of the crucible. Once this flexible rigging is aligned by the steel assembly, the crucible can be safely and securely lifted and manipulated.  
         SUMMARY OF THE INVENTION  
         [0005]    The invention is a device that is used to securely hold a crucible for lifting by a lifting device. It has a circular frame with a top bracing leg that ensures straight vertical lifting and proper alignment of the rigging. The frame diameter is slightly larger than the crucible. Vertical pieces extend downward from the top of the frame. At the bottom end of each of these vertical pieces a hinged piece is attached. On the hinged pieces, a bottom rigging retainer is attached. The bottom rigging retainer allows the rigging to freely pass through it. The bottom rigging retainer with the hinged piece form a loop through which the rigging is thread. The rigging securely holds the bottom of the crucible. A lifting device is attached to the riggings to lift the crucible. The frame can be made adjustable to fit many sizes of crucibles. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    [0006]FIG. 1 is a top view of one embodiment of the invention.  
         [0007]    [0007]FIG. 2 is a side view of one embodiment of the invention.  
         [0008]    [0008]FIG. 3 is a front view of the hinged lifting strut.  
         [0009]    [0009]FIG. 3A is a side view of hinged lifting strut.  
         [0010]    [0010]FIG. 3B is a front view of the hinged lifting strut attached to the vertical piece.  
         [0011]    [0011]FIG. 4 is a side view of the invention with the cable rigging.  
         [0012]    [0012]FIG. 5 is a top view of another embodiment of the invention.  
         [0013]    [0013]FIG. 5A is a side view of another embodiment of the invention.  
         [0014]    [0014]FIG. 6 is a view of the invention holding the crucible and attached to the lifting device.  
         [0015]    [0015]FIG. 7 is a side view of the invention with strap rigging 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]    [0016]FIG. 1 is a prospective view of the fabricated metal assembly  10  of the invention. In the preferred embodiment, the fabricated metal assembly  10  is made of steel. However, other materials can be used that are known in the art. FIG. 2 shows that the fabricated metal assembly  10  is circular in design. The fabricated metal assembly  10  is circular in design because in the preferred embodiment the crucible  30  shown in FIG. 6 is circular. FIGS. 1 and 2 show that the fabricated metal assembly  10  has a top rings  12  and a bottom ring  14 . Both the top and bottom rings  12  and  14  diameters are just slightly larger than the crucible&#39;s  30  diameter. These rings  12  and  14  in the preferred embodiment must be only slightly larger than the crucible&#39;s  30  diameter since the tolerance between the crucible  30  and the melting furnace is usually around three inches. The top and bottom rings  12  and  14  are held together by four side pieces  16 ,  18 ,  20  and  22 . These four side pieces  16 ,  18 ,  20  and  22  are equally spaced around the top and bottom rings  12  and  14 . The top and bottom rings  12  and  14  are attached to the side pieces  16 ,  18 ,  20 , and  22  in the preferred embodiment by welding. However, they could be attached by other methods known in the art such as nuts and bolts. The top and bottom rings,  12  and  14 , are formed with 2×¼ inch HRS steel bar stock. These are formed into the top and bottom rings  12  and  14  and welded together. In the preferred embodiment, the top and bottom rings  12  and  14  are only a quarter inch larger than the outer diameter of the crucible  30 . As I pointed out above, the top and bottom rings  12  and  14  must be only slightly larger than the crucible  30  since on most furnaces there is less than three inches tolerance. The four vertical pieces  16 , 18 ,  20 ,  22  that join the top and bottom rings,  12  and  14 , are made out of 3½×¼ inch HRS steel bar stock.  
         [0017]    All four of the vertical pieces  16 ,  18 ,  20 , and  22  are bent at a 90 degree angle over the top ring  12  to provide additional support. The vertical pieces  16 ,  18 ,  20 , and  22  extend below the bottom ring  14 . In the preferred embodiment the vertical pieces  16 ,  18 ,  20 , and  22  length is equivalent to the distance as measured from the top of the crucible  30  to the point where the crucible&#39;s  30  outside diameter begins to lessen. At the bottom end of each of the four vertical pieces  16 ,  18 ,  20 , and  22 , a male hinge bracket is welded in place. This male hinge bracket could also be attached by other methods known in the art such as nuts and bolts.  
         [0018]    To the top ring  12 , a section of 4×1½ inch U shaped channel  26  is attached. In the preferred embodiment, this U shaped channel  26  is attached by welding. However, there are other methods that are known in the art that could be used to attach the U shaped channel. This U shaped channel  26  is positioned over vertical pieces  18  and  22 . A lifting lug  28  is welded in place directly in the center of the channel  26  to provide balance for vertical lifting of the assembly  10 . At both ends of channel  26  an upper lifting strap retainers  32  are welded into position. The upper lifting strap retainer  32  could be attached by other methods known in the art.  
         [0019]    Four hinged lifting struts  34 ,  36 ,  38 , and  40  shown in FIGS. 2 and 3 are attached to the vertical pieces  16 ,  18 ,  20 , and  22 . These hinged lifting struts  34 ,  36 ,  38 , and  40  are produced from 3½×1 HRS steel bar stock. Each of these four hinged lifting struts  34 ,  36 ,  38  and  40  has a female hinge bracket welded in place to utilize the male hinge brackets. The length of each of the vertical pieces  16 ,  18 ,  20  and  22  and the length of the hinged lifting struts  34 ,  36 ,  38  and  40  cannot exceed or be equal to the overall height of the crucible  30 . Near the end of the four hinged lifting struts  34 ,  36 ,  38  and  40  a lower rigging retainers  44  is welded in place as shown in FIGS. 2 and 4. The lower rigging retainers  44  create a loop. Through each of these loops formed by the lower rigging retainers  44 , the rigging is threaded. The rigging in the preferred embodiment consists of two cables  46  and  47 ; however, it could consist of two pieces of industrial strapping. Each of the cables  46  and  47  has loops  48 ,  49 ,  53 , and  55  at each end. If industrial strapping is used as shown in FIG. 6, each strap  45  and  51  has a loop  57  on one end and a buckle  50  at the other.  
         [0020]    The rigging is thread as follows: First the cable  46  is run through the lower rigging retainer  44  of hinged lifting struts  40  and  38  and cable  47  is ran through the lower rigging retainer  44  of hinged lifting struts  34  and  36 . Second, loop  48  on cable  46  is run through loop  53  on cable  47 . Loop  48  of cable  46  is then run through the upper rigging retainer  32 . Loop  55  on cable  47  is run through loop  49  on cable  46 . Loop  55  of cable  47  is then run through the upper rigging retainer  32 . Thus when the cables  46  and  47  are attached to the lifting device  52  through loops  48  and  55  and the lifting device moves upward the cables  46  and  47  place pressure on the hinged lifting struts  34 ,  36 ,  38 , and  40  and they move inward griping the crucible  30  as shown in FIG. 6.  
         [0021]    For the industrial strapping is used, first the strap  45  is run through the lower rigging retainer  44  of hinged lifting struts  38  and  40  and strap  51  is run through the lower rigging retainer  44  of hinged lifting struts  36  and  34 . Second, buckle  50  on strap  45  is run through loop  57  on strap  51 . Buckle  50  of strap  45  is then run through the upper rigging retainer  32 . Buckle  50  on strap  51  is run through loop  55  on strap  45 . Buckle  50  of strap  51  is then run through the upper rigging retainer  32 . Thus when the straps  45  and  51  are attached to the lifting device  52  through buckle  50  and the lifting device moves upward the straps  45  and  51  place pressure on the hinged lifting struts  34 ,  36 ,  38 , and  40  and they move inward griping the crucible  30 .  
         [0022]    To use the fabricated metal assembly  10  one positions the fabricated metal assembly  10  over the crucible  30 . This can be done by using the lifting lugs  28  located on the U shaped channel of the fabricated metal assembly  10 . The lifting lugs  28  are attached to the vertical lifting device  52  such as a forklift. This is usually done by a set of chains  54  being attached to the lifting lugs  28  and moving the vertical lifting device  52  upward. The vertical lifting device  52  then positions the fabricated metal assembly  10  over the crucible  30 . Then the vertical lifting device  52  begins to lower the fabricated metal assembly  10  and the fabricated metal assembly  10  is positioned by individuals around the crucible  30 . Then the rigging (cables  46  and  47  or straps  45  and  51 ) is attached to the vertical lifting device  52  through the buckles  50  or loop  48  and  55 . As upward pressure is applied by vertical lifting device  52  to the rigging, the rigging place pressure on the hinged lifting struts  34 ,  36 ,  38 , and  40  and the hinged lifting struts  34 ,  36 ,  38 , and  40  move inward griping the crucible  30 . A continued upward movement of the vertical lifting device  52  removes the crucible  30  from the furnace. Once clear of the furnace the vertical lifting device  52  with the crucible  30  as shown in FIG. 6 is moved to another location.  
         [0023]    To disengage the vertical lifting device  52 , the crucible  30  is placed on a firm, flat surface. The rigging is detached and the set of chains  54  are reattached to the lifting lug  28 . The fabricated metal assembly  10  with rigging then is pulled up and removed.  
         [0024]    To place a new crucible  30  in the furnace, the fabricated metal assembly  10  with rigging is lowered over the crucible  30 . The vertical lifting device  52 , through a set of chains  54  is then attached to the rigging by buckles  50  or loops  48  and  55 . The vertical lifting device  52  then lifts, pulling the rigging and the hinged lifting struts  34 ,  36 ,  38 , and  40  securely around the bottom of the crucible  30 . The crucible  30  is then moved into place over the furnace and the vertical lifting device  52  lowers the crucible  30  down into the furnace. Once the crucible  30  is in place the vertical lifting device  52  continues to lower to take the pressure from the rigging. The rigging is then detached from the vertical lifting device  52 . The vertical lifting device  52  then is reattached to the lifting lugs  28 , and lifts the fabricated metal assembly up  10  and rigging out of the furnace and off the crucible  30 . The crucible  30  is now in place and ready for use.  
         [0025]    [0025]FIGS. 5 and 5A shows another embodiment of the invention. This embodiment is designed to fit crucibles of several different sizes. In the preferred embodiment of the design of FIGS. 5 and 5A, the fabricated metal assembly  110  is made of steel. Fabricated metal assembly can be made of other materials that are known in the art. FIG. 5 is a top view of the fabricated metal assembly  110 . FIG. 5 shows a fabricated metal assembly as four legs  112 ,  113 ,  114 , and  115  that are assembled in a plus sign. By looking at FIGS. 5 and 5A, one can see that each of the four legs  112 ,  113 ,  114  and  115 ,is attached to one of the four vertical side pieces  116 ,  118 ,  120  and  122 . The four vertical side pieces  116 ,  118 ,  120  and  122  are attached to the ends of the four legs  112 ,  113 ,  114  and  115  by welding. However, other methods of attachment known in the art can be used.  
         [0026]    The four legs  112 ,  113 ,  114 , and  115  are assembled as follows: Three pieces of box channel  124  and  126 , are attached together in the center forming a shape similar to a plus sign. Into each of the four ends of the two pieces of box channel  124  and  126 , are run a piece of smaller box channel  128 ,  130 ,  132  and  134 . This smaller box channel  128 ,  130 ,  132 , and  134  is adapted such that the smaller box channel  128 ,  130 ,  132 , and  134  will easily move in and out of the two pieces of box channel  124  and  126 . To the ends of the smaller box channel  128 ,  130 ,  132  and  134  that are not within box channel  124  and  126  are attached the four vertical pieces  116 ,  118 ,  120  and  122 . In the center of the top piece of the box channel  124 , a lifting lug  28  is placed. This lifting lug  28  is placed directly in the center of box channel  124  to provide balance for vertical lifting of the assembly  110 . To the end of the smaller box channels  128  and  130 , which fit within box channel  124  an upper lifting strap retainer  32  is welded into position. The upper lift strap retainer  32  could be attached by other methods known in the art.  
         [0027]    A removable ring  190  is attached to each of the four vertical pieces  116 ,  118 ,  120 , and  122  near the end of the four vertical pieces  116 ,  118 ,  120 , and  122 . In the preferred embodiment, the ring is attached with bolts so that it can easily be removed. The rings diameter is just slightly larger than the crucible  30 . A different size ring  190  is necessary for each crucible  30  of a different diameter.  
         [0028]    Four hinged lifting struts  34 ,  36 ,  38 , and  40  are attached to the vertical pieces  116 ,  118 ,  120 , and  122 . These hinged lifting struts  34 ,  36 ,  38 , and  40  are attached to the end of the four vertical pieces  116 ,  118 ,  120  and  122  that are attached to the smaller box channels  128 ,  130 ,  132  and  134 . These hinged lifting struts  34 ,  36 ,  38 , and  40  are made of steel bar stock. Each of the four hinged lifting struts  34 ,  36 ,  38 , and  40  has a female hinge bracket welded in place at one end. The four vertical pieces  116 ,  118 ,  120  and  122  have attached at their end that is not attached to the smaller box channel  128 ,  130 ,  132  and  134  a male hinge bracket. The female hinge bracket attached to hinged lifting struts  34 ,  36 ,  38 , and  40  is adapted to attach to the male hinge bracket at the end of each of the vertical pieces  116 ,  118 ,  120  and  122 . Attached to each of the four lifting struts  34 ,  36 ,  38 , and  40  is a lower rigging retainer  44 . Through each of these lower rigging retainers  44  the rigging is threaded.  
         [0029]    As in the previous embodiment, the rigging can be cable or industrial strapping. The rigging is thread as in the previous embodiment. First, the cable  46  is run through the lower rigging retainer  44  of hinged lifting struts  38  and  40  and cable  47  is run through the lower rigging retainer  44  of hinged lifting struts  34  and  36 . Second, loop  48  on cable  46  is run through loop  53  on cable  47 . Loop  48  of cable  46  is then run through the upper rigging retainer  32 . Loop  55  on cable  47  is run through loop  49  on cable  46 . Loop  55  of cable  47  is then run through the upper rigging retainer  32 . Thus when the cables  46  and  47  are attached to the lifting device  53  through loops  48  and  55  and the lifting device moves upward the cables  46  and  47  place pressure on the hinged lifting struts  34 ,  36 ,  38 , and  40  and they move inward griping the crucible  30  as shown in FIG. 6.  
         [0030]    For the industrial strapping is used, first the strap  45  is run through the lower rigging retainer  44  of hinged lifting struts  38  and  40  and strap  51  is run through the lower rigging retainer  44  of hinged lifting struts  34  and  36 . Second, buckle  50  on strap  45  is run through loop  57  on strap  51 . Buckle  50  of strap  45  is then run through the upper rigging retainer  32 . Buckle  50  on strap  51  is run through loop  55  on strap  45 . Buckle  50  of strap  51  is then run through the upper rigging retainer  32 . Thus when the straps  45  and  51  are attached to the lifting device  53  through buckle  50  and the lifting device moves upward the straps  45  and  51  place pressure on the hinged lifting struts  34 ,  36 ,  38 , and  40  and they move inward griping the crucible  30 .  
         [0031]    To use the fabricated metal assembly  110 , one must first adjust the legs  112 ,  113 ,  114 , and  115 . To adjust the legs  112 ,  113 ,  114  and  115 , one pulls the smaller box channels  128 ,  130 ,  132 , and  134  from the box channels  124  and  126 . Box channel  124  and  126  has an opening  192 . In each of the smaller box channels  128 ,  130 ,  132  and  134  are a set of openings. These openings  192  and the set of openings are adapted that the openings  192  in box channel  124  and  126  line up with the set of openings in smaller box channel  128 ,  130 ,  132 , and  134 . The legs  112 ,  113 ,  114  and  115  are lengthened or shortened by pulling out or pushing in on the smaller box channels  128 ,  130 ,  132  and  134  to a position that the legs  112 ,  113 ,  114  and  115  are just slightly longer than the diameter of the crucible  30 . When one finds the legs  112 ,  113 ,  114  and  115  are slightly longer then the diameter, one lines up the nearest opening  197  in the smaller box channels  128 ,  130 ,  132  and  134  with one of the openings  193  in the box channel  124  and  126  and places a pin  162  to hold the smaller box channels  128 ,  130 ,  132  and  134  in place. Then the proper sized ring  190  is attached to the four vertical pieces  116 ,  118 ,  120 , and  122 .  
         [0032]    The fabricated metal frame  110  can also be adjusted to fit crucible  30  of different height. Each of the four vertical pieces  116 ,  118 ,  120  and  122  has several sets of openings  168 . These openings  168  are adapted to hold a bolt  170 . An L shaped adjustable height bracket  172  also has an opening  174  through which bolt  170  fits. To adjust the height properly, one measures the distance from the top of the crucible  30  to the point where the crucible&#39;s  30  outside diameter begins to lessen. Then one measures vertical pieces  116 ,  118 ,  120  and  122  from their bottom end where the male hinge bracket is attached and moves up the side of the vertical pieces  116 ,  118 ,  120  and  122  to an opening in the set of openings  168  that is just below the measurement from the crucible  30 . One places the adjustable height bracket  172  at this point by placing the bolt  170  through the opening  174  in the adjustable height bracket  172  and the opening in the set of openings  168  in the vertical pieces  116 ,  118 ,  120 , and  122 . One does this for all four vertical pieces  116 ,  118 ,  120 , and  122 .  
         [0033]    After the height and the diameter of the fabricated metal assembly  110  are adjusted, one moves the fabricated metal assembly  110  into position over the crucible  30 . This can be done by using the lifting lugs  28  on the box channel  124  of the fabricated metal assembly  110 . The lifting lug  28  is attached to a vertical lifting device  52  such as a forklift. This is usually done by a set of chains and hook  54  being attached to the lifting lug  28  and moving the vertical lifting device  52  upward. The vertical lifting device  52  then positions the fabricated metal assembly  110  over the furnace. Then the vertical lifting device  52  begins to lower the fabricated metal assembly  110 . The fabricated metal assembly  110  is positioned by individuals around the crucible  30 . The chain  54  is then detached from the lifting lug  28  and attached to the rigging. As the upward pressure is applied by the vertical lifting device  52  to the rigging, the rigging securely grasps the bottom of the crucible  30 . The continued upward movement of the vertical lifting device  52  removes the crucible  30  from the furnace. Once clear of the furnace, the vertical lifting device  52  and the crucible  30  are moved to another location.  
         [0034]    To place a new crucible  30  back in the furnace the fabricated metal assembly  110  is lowered over crucible  30  by the lifting device  52 . The chain  54  is then detached from the lifting lug  28  and attached to the rigging. The crucible  30  is then moved by the vertical lifting device  52  into place over the furnace and the vertical lifting device  52  lowers the crucible  30  into the furnace. Once the crucible  30  is in place the vertical lifting device  52  continues to lower to take the pressure off the rigging. The rigging is then detached from the vertical lifting device  52 . The vertical lifting device  52  then is reattached to the lifting lug  28  and lifts the fabricated metal assembly  110  out of the furnace and off the crucible  30 . The crucible  30  is now in place and ready for use.  
         [0035]    Changes and modifications in the specifically described embodiments can be carried out without departing from the scope of the invention which is intended to be limited only by the scope of the appending claims.