Abstract:
A multi-piece interconnected body for use in at least structural support and/or in creating internal cavities for an improved strength-to-weight ratio in a variety of structures is nestable prior to its assembly and use. When assembled, the device preferably forms a generally spherical and hollow body, with (1) one or more ribs or similar structural support network associated with and/or integrally formed in the body; (2) at least one latch mechanism to help hold the pieces in a desired assembled relationship with each other; and (3) a hinge or other interconnecting element that facilitates nesting and/or stacking of a plurality of the bodies with each other prior to assembly, association of the multiple parts of each body with each other prior to assembly, and ready repositioning of those parts into a desired assembled position.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates generally to structural components and related methods, and more specifically to a nestable spherical hollow body that is convenient to use and assemble at least for structural support and/or creating internal cavities in concrete or similar applications. 
       BACKGROUND OF THE INVENTION 
       [0002]    Many concrete or similar structural components conventionally are relatively thick and heavy, compared to their weight bearing capacity. The formation of voids within concrete can improve the economics, performance, and versatility of the concrete and its implementation. 
         [0003]    Prestressed, prefabricated concrete elements with extended cross sections and internal hollow cylindrical cavities have been used to reduce the weight “problems”, but they typically only span in a “single” direction. In other words, they are typically relatively long and narrow concrete beams with one or more web elements extending significantly below the concrete “deck.” Alternative approaches have included placing lightweight balls within the concrete as it is poured (for example, see DE 2,116,479) or similarly positioning hollow spheres within a mesh assembly in the concrete (for example, see U.S. Pat. No. 5,396,747, issued to Breuning in 1995). 
         [0004]    A system using embedded blow-molded plastic balls is described at the website of BubbleDeck North America Ltd. BubbleDeck currently produces a pre-fabricated solid concrete slab structure having plastic balls embedded in concrete, to reduce the slab&#39;s weight. According to BubbleDeck, the pre-fabricated concrete slab can reduce construction material weight by up to fifty percent (50%). The BubbleDeck plastic balls are hollow, spherical shapes (similar to ping pong balls), and are of a solid fixed single piece construction. That single piece hollow body construction apparently has a generally uniform wall thickness sufficient to withstand the stress imposed by the surrounding concrete material, but that solid fixed single piece construction limits at least the shipping and handling characteristics of the inserts (balls) prior to use, and can also affect the stress handling capacity of the plastic balls. 
         [0005]    Thus, the weight advantages of systems such as the BubbleDeck balls are compromised by certain disadvantages inherent in their design. Among other things, because they are blow-molded spheres, they are cannot be efficiently stored or transported prior to their use on a jobsite. 
       SUMMARY OF THE INVENTION 
       [0006]    The invention is directed to a nestable hollow body that, among other things, is useful for at least structural support and/or creating internal cavities for an improved strength-to-weight ratio in a variety of concrete or other structures. Rather than a series of loose components separate from each other (see, for example, FIGS. 3-5 of the aforementioned &#39;747 patent), the present invention preferably provides a single connected element whose parts can be easily moved (via hinges or otherwise) from an “open” or nestable position into a “closed” or assembled position. The invention provides for, among other things, nestabilty in a hollow body, and provides for space saving and efficient methods of manufacturing, handling, storing, transporting, and/or assembling the hollow bodies. The invention further facilitates additional structural support within the hollow body itself, to increase the load bearing capacity of the hollow body when subjected to external forces such as those commonly imposed on it by concrete or when otherwise used for its intended purposes. 
         [0007]    In one embodiment, the device is preferably a multi-section hollow body having: (1) a structural support network disposed within or formed in its interior; (2) a hinge mechanism to keep the sections connected to each other prior to assembly and to permit repositioning (or “closing”) of the sections into a final desired configuration prior to their use; and (3) at least one latch mechanism to help hold the sections in that final desired configuration prior to their use. For embodiments having two sections formed of plastic via injection molding, an integral hinge preferably permits a top or first section of the hollow body and a bottom or second section of the hollow body to be (1) fabricated in an opened or an extended state (which permits stacking or nesting of a plurality of hollow bodies on top of each other prior to their eventual use), and then (2) moved to a closed or an assembled state to permit use of the hollow body for its intended purposes. 
         [0008]    Methods of fabrication, transportation, and use related to the aforementioned apparatus are also described herein. Among other things, such methods improve the efficiency of storage and transport and assembly of the void-making devices prior to their use in a concrete or similar construction application. 
         [0009]    Certain objects and advantages have been and are further described herein. Persons of ordinary skill in the art will understand that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. 
         [0010]    These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective view showing a multi-portion hollow body in a closed or assembled state, in accordance with one embodiment of the present invention. 
           [0012]      FIG. 2  is similar to  FIG. 1 , but shows the hollow body in a slightly open position. 
           [0013]      FIG. 3  is a perspective view looking down into the interior of the body of  FIG. 2  after it has been further opened, and illustrates an embodiment of a structural support network disposed within each of the sections of the body. 
           [0014]      FIG. 4(   a ) is a side perspective view of a plurality of the bodies of  FIG. 3 , inverted and stacked and nested with each other. 
           [0015]      FIG. 4(   b ) is a sectional view of the stacked and nested bodies of  FIG. 4(   a ), with the section being taken along the widest portion of the bodies and generally parallel to the plane of the paper on which  FIG. 4(   a ) is shown. 
           [0016]      FIG. 5  is similar to  FIG. 3 , but shows a close-up view of the central interconnecting portion of the body, illustrating one embodiment of a hinge that can be used in the hollow body of  FIG. 1 . 
           [0017]      FIG. 6  is similar to  FIG. 2 , but shows a close-up view of one embodiment of a latch mechanism that can be used in the hollow body of  FIG. 1 . 
           [0018]      FIG. 7(   a ) is similar to  FIG. 6 , but shows the latch mechanism in a closed or secured position, such as the position shown in  FIG. 1 .  FIG. 7(   b ) is similar to  FIG. 7(   a ), but shows a partially sectional perspective view of the latch mechanism, with the section taken in a generally vertical plane through  FIG. 7(   a ). 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Embodiments of the present invention will now be described with references to the accompanying Figures, wherein like reference numerals refer to like elements throughout. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner, simply because it is being utilized in conjunction with a detailed description of certain embodiments of the invention. Furthermore, various embodiments of the invention (whether or not specifically described herein) may include novel features, no single one of which is solely responsible for its desirable attributes or which is essential to practicing the invention herein described. 
         [0020]    Persons of ordinary skill in the art will understand that the invention can be practiced using any of a wide variety of suitable processes and materials. By way of example and not by way of limitation, fabrication processes include die cast, investment casting, sheet metal stamping, single/twin sheet thermo-form, blow-molding, rotational molding, injection molding, gas assist, water assist, web molding, structural foam molding, and many other existing and new processes that may come into being. Materials are not limited in anyway and could extend from metals to resins of all types. A preferred material is plastic, and a preferred method of fabrication is by injection molding. 
         [0021]    The device described herein may generally be used for at least structural support and/or creating internal cavities for improved strength-to-weight ratio in a variety of structures. In this regard, the structural hollow bodies described herein are typically intended to be embedded in concrete or some other material for the purpose of eliminating the concrete or some other material that has weight but no carrying effect. Persons of ordinary skill in the art will understand that although the aforementioned application may be a preferred use, the structural hollow bodies described herein may be used in any number of other applications. 
         [0022]    As shown in  FIGS. 1-4 , in one embodiment, the device is preferably a hollow body  5  having: (1) a top/first section  10  and a bottom/second section  15  of substantially the same size and shape; (2) a structural support network  20  disposed within the hollow body  5  to increase the load bearing capacity of the hollow body  5  when subjected to external forces; (3) at least one latch mechanism  25  positioned along the periphery  40  of the hollow body  5 ; and (4) a corresponding hinge  30  positioned along the periphery  40  of the hollow body  5  so as to permit repositioning of the top section  10  of the hollow body  5  and the bottom section  15  of the hollow body  5  from an opened state, to permit nesting of a plurality of such hollow bodies  5  on top of each other, to a closed state to permit use of the hollow body  5  for its intended purposes. Persons of ordinary skill in the art will understand that the orientation of “top” or “bottom” used herein is for convenience only, and that the specific orientation of the body within a particular application can be any direction. 
         [0023]    The geometric shape of the device  5  described herein is preferably spherical, having a top section  10  and a bottom section  15  of substantially the same size and shape (i.e., half spheres). However, persons of ordinary skill in the art will understand that as long as the general attributes and principles of the device (hollow body)  5  as described herein are utilized, the device  5  can be of virtually any size and shape. Such shapes may include a square, triangle, hexagon, geodesic dome/sphere, or other shape. In addition, the wall thickness of the hollow body  5  and/or structural support network  20  may vary and will typically depend on the device&#39;s intended use or application. 
         [0024]    As shown in  FIG. 5 , the preferred hinge  30  (connecting the top section to the bottom section) is formed as part of an area of reduced thickness of plastic  35  along the periphery  40  between the top section  10  and the bottom section  15  of the hollow body  5 . For injection molded embodiments, the hinge can be a “living hinge” formed of the same plastic as the rest of the body. 
         [0025]    When used for their intended purposes (i.e., for structural support and/or creating internal cavities for improved strength-to-weight ratio in a variety of structures), the hollow bodies  5  preferably are in a closed or assembled state, as shown in  FIG. 1 . No further repositioning of the top section  10  of the hollow body  5  relative to the bottom section  15  of the hollow body  5  is needed. While other more durable hinge types may be utilized, the hinge  30  is intended for a single use application so its durability is relatively less important than its lightweight and cost effective production. 
         [0026]    As shown in  FIG. 4 , the hinge  30  permits the hollow bodies  5  to be shipped or transported from the manufacturer to an end user in an opened or an extended state to facilitate efficient stacking and/or nesting of a plurality of such hollow bodies  5  on top of each other, thereby increasing the number of hollow bodies  5  capable of being contained in a given space (as compared to the number of assembled hollow bodies (or fixed, single piece ping-pong ball type bodies) capable of being contained in the same space). 
         [0027]    As shown in  FIGS. 2 and 3 , the hollow body  5  preferably includes at least one latch mechanism  25 , and preferably includes a plurality of such latch mechanisms  25 . The latch mechanism  25  preferably includes an enlarged head or male portion  45  formed on the periphery  40  and protruding from a first recessed portion  50  formed on one of the top section  10  or a bottom section  15  of the hollow body  5 , and a correspondingly shaped cavity or female portion  55  formed on the periphery  40  as part of a second recessed portion  60  on the other one of the top section  10  or the bottom section  15  of the hollow body  5  for receiving or mating with the head  45  to join, close, or seal the top and bottom sections  10 ,  15  along the peripheral  40  (mating area between the top section  10  and bottom section  15  of the hollow body) when the hollow body  5  is in the closed or assembled state. 
         [0028]    As shown in  FIGS. 7(   a )-( b ), the head  45  preferably is constructed with an enlarged protrusion  65  such that, as the head  45  makes initial contact with the cavity  55 , the head  45  moves in a direction away from the periphery  40  of the hollow body  5  so as to be received into the cavity  55 . After the head  45  is completely received into the cavity  55 , material memory (and/or compressive hoop stress) causes the head  45  to move back out into its original position, securing the protruding portion  65  of the head  45  firmly against a lip  70  of the cavity  55 , and securing the top section  10  of the hollow body  5  to the bottom section  15  of the hollow body  5  along the peripheral edges  40 . 
         [0029]    Similar to the hinge  30 , the latch  25  is intended for a single use application. In this regard, once secured in the closed or assembled state the hollow body  5  is ready for its intended use. No further repositioning of the top section  10  of the hollow body  5  relative to the bottom section  15  of the hollow body  5  is needed. A plurality of latch mechanisms  25  are preferably provided and used, to increase the integrity of the hollow body  5  in its closed or “sealed” state (i.e., to maximize accurate engagement and minimize the risk of collapse or deformation of the hollow body  5  due to external stress resulting in partial or total separation of the top section  10  from the bottom section  15 , or other “failure” of the body&#39;s void-making purpose in certain applications). 
         [0030]    In certain applications such as forming voids in concrete, it is unlikely that the assembled ball or body will ever need to be “opened.” Accordingly, securing the top section  10  of the hollow body  5  to the bottom section  15  of the hollow body  5  is of primary importance, and the ability to “unsecure” or open the latch mechanism(s)  25  is moot, undesirable, and/or irrelevant. 
         [0031]    Persons of ordinary skill in the art will understand that any suitable latch may be utilized within the scope of the invention. In this regard, and by way of example, even if just a single latch element  25  is provided on the hollow body, the sealing or further securing of the top section  10  of the hollow body  5  to the bottom section  15  of the hollow body  5  along the periphery  40  may be further aided or facilitated in any number of ways, including the use of a mating tongue and groove structure and/or gasket member along the periphery  40 , for example. 
         [0032]    As best shown in  FIG. 1 , the hinge  30  and latch(es)  25  preferably are constructed such that in the closed or assembled state the hinge  30  and latch(es)  25  do not protrude beyond the designated outside diameter of the hollow body  5 . In this regard, as indicated above, each of the hinge  30  and latch(es)  25  are formed on a recessed portion  50 ,  60  of the top section  10  of the hollow body  5  and the bottom section  15  of the hollow body  5 . Accordingly, as shown in  FIG. 7(   a ), each recessed portion  50 ,  60  is sloped (as indicated by reference “s”) such that the hinge  30  and latch(es)  25  formed on the periphery  40  as part of each recess  50 ,  60  are inset a distance (as indicated by reference “i”) from the perimeter  40  of the hollow body  5 . Among other things, such an inset “i” configuration of the hinge  30  and latch(es)  25  provides a generally smooth outer periphery  40  or profile of the hollow body  4  for purposes of efficient and stable stacking or nesting of a plurality of such hollow bodies  5  on top of each other in the opened or extended state as shown in  FIGS. 4(   a )-( b ). 
         [0033]    As shown in  FIG. 3 , each of the top section  10  and the bottom section  15  of the hollow body  5  preferably includes a structural support network  20  (or web or rib(s)) formed on or disposed in or operatively affixed to the body section or sections. Among other things, the structural support network  20  can increase the load bearing capacity of the hollow body  5  when subjected to the external forces commonly imposed on it, when used for at least structural support and/or to create internal cavities in a variety of structures. The structural support network  20  disposed within the hollow body  5  may be considered as somewhat of a compromise between a hollow body  5  without such a structural support  20  and a completely solid hollow body. In this regard, the structural support network  20  permits a greater load bearing capacity than a hollow body  5  without such a structural support network  20 , but at a reduced weight when compared to a completely solid body. 
         [0034]    In one embodiment, the reinforcing ribs or structural support network  20  includes a concentric ring  75  positioned generally near a central or bottom portion  80  of each of the top section  10  and the bottom section  15  of the hollow body  5 . In other words, in this embodiment, the concentric ring  75  is distal from the periphery opening  40  of the hollow body  5 . Preferably, a plurality of equally spaced (or other pattern of) support arms  85  radiate outward from the concentric ring  75  toward the periphery  40  of each of the top section  10  and the bottom section  15  to add structural stability to the hollow body sidewall. 
         [0035]    Persons of ordinary skill in the art will understand that the invention can be practiced in other embodiments without any such ribs or webbing, or with any of a wide variety of patterns, shapes, and sizes of ribs or similar support network. Similarly, persons of ordinary skill in the art will understand that, among other things, the diameter, depth, and/or thickness of the concentric ring  75  as well as the number, spacing, and length of each support arm  85  may vary depending on the hollow body&#39;s intended purpose or application. For example, a hollow body structural support network  20  (a concentric ring  75  and one or more of the associated support arms  85 ) intended to withstand the force imposed on a hollow body  5  buried or encased in concrete may be constructed considerably thicker and/or larger in some aspect as compared to a hollow body structural support network  20  that is intended to be buried or encased in some lighter material. 
         [0036]    The apparatus and methods of the present invention have been described with some particularity, but the specific designs, constructions and steps disclosed are not to be taken as delimiting of the invention. Obvious modifications will make themselves apparent to those of ordinary skill in the art, all of which will not depart from the essence of the invention and all such changes and modifications are intended to be encompassed within the appended claims, to the extent permitted by any prior art and applicable law.