Abstract:
An insert is provided for forming a void in precast concrete that includes a tube defined by a wall and having a plurality of formed, longitudinally spaced-apart ribs that project radially outwardly from an outer surface of the wall. A plurality of corresponding recesses are defined in an interior surface of the wall. A plurality of score lines are positioned between the ribs so that the tube may be adjusted in length to meet the particular requirements associated with a specific design of precast concrete. At least one removable cap is positioned in an open end of the tube so as to prevent concrete from entering the tube during casting. A method for forming a void within a precast concrete structure is also provided in which the tubular sleeve assembly is positioned within a form containing uncured concrete, and one or more of the score lines are cut so as to adjust the length of the tube.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention generally relates to prefabricated building materials, and more particularly, to devices used in the manufacture of precast concrete structural elements.  
         BACKGROUND OF THE INVENTION  
         [0002]    Conventional commercial construction projects, e.g., parking garages, commercial buildings, stadiums, bridges, overpasses and the like, have often involved the on site formation of a series of temporary forms for casting reinforced concrete structural members, which forms are later removed once the concrete has cured. This is generally a relatively long and drawn out process, as it is necessary initially to construct the temporary foundation forms, then wait for the concrete to cure before forming further concrete structures above the foundations, with a further delay for curing before finally forming the pier caps and upper structure.  
           [0003]    It has become known in the art to manufacture such commercial structures from precast concrete building elements, such as, columns, walls, stairs, architectural concrete facades, insulated wall panels, beams, stadium risers, double tees, girders, spandrel beams, floor slabs, and the like. During manufacture, it is customary to provide voids (e.g., tunnels or passageways) within these building elements for embedding posts and fasteners or inserting portions of other precast structural elements, when assembling and solidly anchoring them together to form a portion of a commercial structure. The voids are not typically utilized until the concrete has hardened or cured to a desired state, and the precast structural element is delivered to a construction site. It is often the case that the void may be exposed to rainfall, or there may be an accumulation of particles of foreign matter in the void which will interfere with insertion of other pieces into the void. As a result, it is often necessary to close off the void prior to use.  
           [0004]    Various methods and apparatus are known in the prior art for creating such voids in poured concrete. For example, voids may be provided at the construction site by simply core drilling the structure at the time. Such a procedure may be difficult to control accurately, and is often very costly.  
           [0005]    In U.S. Pat. No. 1,954,788, issued to Chambliss, Jr. et al., an aperture-forming mold is disclosed for the construction of concrete floors, walls, and the like with apertures or openings therein for wires, piping, and other desired purposes.  
           [0006]    U.S. Pat. No. 3,020,615, issued to Peters, relates generally to conduit molding forms such as are used by cement contractors, construction workers and the like for facilitating rapid removal of the core from a molded conduit. Peters&#39; molding form is arranged so as to avoid becoming bonded to the concrete, and permits removal of the form without the use of special tools. The form can be cut to different lengths, as needed, for a particular molding operation.  
           [0007]    U.S. Pat. No. 3,205,634, issued to Wagner, discloses post sleeves for concrete foundations that are used to facilitate erection of structures by inserting posts, legs, or other parts within the sleeves.  
           [0008]    U.S. Pat. No. 3,265,349, issued to Hamrick, discloses the formation of a passageway through a poured concrete structure, such as a wall or a floor using a metal sleeve mold. This type of metal sleeve can cause corrosion problems. Also, if the metal sleeve be set out of square alignment, as can easily occur, an embedded item would be prevented from fitting into the void properly. Corrective action would be to chip away the concrete around the metal sleeve and then burn the sleeve out with a cutting torch.  
           [0009]    U.S. Pat. No. 3,933,336, issued to Tolf, Jr., discloses a pipe sleeve used to form a hole when pouring a concrete slab. The pipe sleeve includes a tubular side wall having an end wall closing one end and a radially outwardly extending flange at the other end. Longitudinally extending ribs are formed on the outside surface of the side wall, and a plurality of grooves are formed in the inner surface of this side wall. The side wall is tapered, and due to this taper, the pipe sleeves may be compactly stacked for storage or for shipping purposes. The sleeve may be used either in its original length or in a shorter length by cutting the side wall to a desired length and then telescoping the two cut sections together. When stacked for shipping or storage, the ribs are located in the grooves, but when two cut sections are telescoped, the ribs are out of the grooves and tightly bind the two sections together.  
           [0010]    U.S. Pat. No. 4,515,271, issued to Auciello et al., discloses forming a void in poured concrete using a tubular structure formed of sheet material closed at upper and lower ends by means of an upper closure element and a lower closure element, respectively. The inner surface of the tubular structure presents a helical score line extending between the bottom of the tubular structure and the upper closure element. The upper closure element is formed integrally with the tubular sheet material and constructed at an upper side with tabs for handling the insert and especially for lifting the upper closure element and pulling away the tubular structure along the score line to leave a void. The tubular structure consists of a tapered configuration which decreases in size from the bottom to the top. This tapered construction allows a plurality of the tubular inserts to be arranged in nested relationship with the holder tab being operable to maintain upper closure elements of the nested inserts spaced away from one another.  
           [0011]    Because none of the prior art devices are completely satisfactory, there exists a need for a better way of forming voids in precast concrete structural building elements.  
         SUMMARY OF THE INVENTION  
         [0012]    The present invention provides an insert for forming a void in precast concrete. A preferred embodiment includes a tube defined by a wall and having a plurality of formed, longitudinally spaced-apart ribs that project radially outwardly from an outer surface of the wall. A plurality of corresponding recesses are defined in an interior surface of the wall and are accessible from an interior portion of the tube. Advantageously, a plurality of score lines are positioned between the ribs so that the tube may be adjusted in length to meet the particular requirements associated with a specific design of precast concrete. At least one removable cap is positioned in an open end of the tube so as to prevent concrete from entering the tube during casting.  
           [0013]    A method for forming a void within a precast concrete structure is also provided in which a tubular sleeve assembly is positioned within a form containing uncured concrete, where the tubular sleeve assembly comprises an open ended tube defined by a wall with a plurality of formed, longitudinally spaced-apart ribs that project radially outwardly from an outer surface of the wall. A plurality of corresponding recesses are defined in an interior surface of the wall that are accessible from an interior portion of the tube. A plurality of score lines are formed between the ribs, one or more of which may cut so as to adjust the length of the tube. A removable cap is positioned in each open end of the tube so as to prevent the ingress of concrete during manufacture. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    These and other features and advantages of the present invention will be more fully disclosed in, or rendered obvious by, the following detailed description of the preferred embodiment of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein:  
         [0015]    [0015]FIG. 1 is a perspective view of a tubular sleeve assembly formed in accordance with the present invention;  
         [0016]    [0016]FIG. 2 is an exploded perspective view of the tubular sleeve assembly shown in FIG. 1;  
         [0017]    [0017]FIG. 3 is an exploded cross-sectional view of the tubular sleeve assembly shown in FIG. 2;  
         [0018]    [0018]FIGS. 4 and 5 are broken-away cross-sectional views of the end portions of the tubular sleeve assembly of the present invention;  
         [0019]    [0019]FIGS. 6 and 7 are broken-away cross-sectional views of the ends of the tubular sleeve assemblies shown in FIGS. 4 and 5, with the end caps positioned within the tube;  
         [0020]    [0020]FIG. 8 is a broken-away perspective view of a concrete form having two tubular sleeve assemblies formed in accordance with the present invention positioned within the form;  
         [0021]    [0021]FIG. 9 is a broken-away cross-sectional view of cured precast concrete structure including the tubular sleeve assembly shown in FIG. 8, as taken along the lines  9 - 9  in FIG. 8;  
         [0022]    [0022]FIG. 10 is a broken-away enlarged cross-sectional view of the precast concrete structure and tubular sleeve assembly shown in FIG. 9, illustrating the removal of a portion of the tube;  
         [0023]    [0023]FIG. 11 is a broken-way cross-sectional view of a precast concrete structure having a tubular sleeve assembly formed in accordance with the present invention positioned within the structure; and  
         [0024]    [0024]FIG. 12 is a broken-away cross-sectional view similar to FIG. 11, showing a method of transporting the precast concrete structure member utilizing the tubular sleeve assembly of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    This description of preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. The drawing figures are not necessarily to scale and certain features of the invention may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as “horizontal,” “vertical,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. In the claims, means-plus-function clauses are intended to cover the structures described, suggested, or rendered obvious by the written description or drawings for performing the recited function, including not only structural equivalents but also equivalent structures.  
         [0026]    Referring to FIGS.  1 - 5 , a tubular sleeve assembly  5  formed in accordance with the present invention, and adapted for the creation of a void in a precast concrete structure  8  (FIG. 9), comprises an elongate tube  10  and a pair of end caps  12 . Tube  10  includes a first end  13  having an opening  14  that leads into a central passageway  17 . Tube  10  also includes a second end  20  having an opening  23  that leads into central passageway  17 . Tube  10  is often molded from a polymer material so as to comprise a circular cross-section with a diameter of about three inches. Polymeric materials useful in this invention include any material useful in the construction industry, including, without limitation, thermoplastics (crystalline or non-crystalline, cross-linked or non-cross-linked), thermosetting resins, elastomers or blends or composites thereof. Illustrative examples of useful thermoplastic polymers include, without limitation, polyolefins, such as polyethylene or polypropylene, copolymers (including terpolymers, etc.) of olefins such as ethylene and propylene, with each other and with other monomers such as vinyl esters, acids or esters thereof -unsaturated organic acids or mixtures thereof, halogenated vinyl or vinylidene polymers such as polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride and copolymers of these monomers with each other or with other unsaturated monomers, polyesters, such as poly(hexamethylene adipate or sebacate), poly(ethylene terephthalate) and poly(tetramethylene terephthalate), polyamides such as Nylon-6, Nylon-6,6, Nylon-6,10, Versamids, polystyrene, polyacrylonitrile, thermoplastic silicone resins, thermoplastic polyethers, thermoplastic modified cellulose, polysulphones and the like.  
         [0027]    A plurality of spaced-apart ribs  26  are formed along a first portion of first end  13  so as to project radially outwardly from the outer surface of tube  10 . As a result of this construction, a plurality of recesses  30 , that correspond to plurality of spaced-apart ribs  26 , are defined by the inner surface of tube  10 . Ribs  26  are typically spaced apart by about two inches. A plurality of score lines  34  are formed in the surface of tube  10 , i.e., a circumferential groove or weakening of the tube that is molded or cut (scored) into the surface of tube  10 . One scoreline  34  is formed between each pair of adjacent ribs  26  so as to be positioned at predetermined intervals along the length of the first portion of first end  13 . A single rib  37  is formed in second end  20  of tube  10  adjacent to, but spaced from the edge of tube  10  that defines opening  23 . A recess  39 , adjacent to single rib  37 , is defined by the inner surface of tube  10 . The transverse center-line of single rib  37  is spaced away from the edge of tube  10  by a distance that is substantially equal to the distance from a score line  34  to the transverse center-line of an adjacent rib  26 .  
         [0028]    Referring to FIGS.  2 - 5 , end caps  12  comprise a cylindrical body  40 , a end wall  42 , and an annular snap-rib  45 . More particularly, cylindrical body  40  is often hollow, with an open end edge  46 . The-outer diameter of cylindrical body  40  is somewhat smaller than the inner diameter of tube  10 . End wall  42  is disposed at one end of cylindrical body  40 , and is sized so as to form a brim  47  that projects radially outwardly from the end edge of cylindrical body  40 . Snap-rib  45  projects radially outwardly from cylindrical body  40  in spaced relation to brim  47 , and adjacent to, but spaced from end edge  46 .  
         [0029]    Advantageously, snap-rib  45  is sized and shaped to be received within one of recesses  30  or  39 , i.e., the transverse center-line of snap-rib  45  is spaced away from end edge  46  by a distance that is substantially equal to the distance from a score line  34  to the transverse center-line of an adjacent rib  26  or, from the end edge of end  20  to recess  39 .  
         [0030]    Referring to FIGS.  8 - 12 , tubular sleeve assembly  5  is arranged with end caps  12  assembled in opening  14  of first end  13  and opening  23  of second end  20  so as to prevent ingress of concrete during placement within form  50 . To begin, an end cap  12  is arranged in confronting coaxial relation with second end  20  of tube  10  such that open end edge  46  is positioned adjacent to opening  23 . Once in this position, end cap  12  is moved toward tube  10  so that edge  46  enters opening  23  of tube  10 . End cap  12  continues into tube  10  until annular snap-rib  45  slips into and is captured by recess  39  corresponding to single rib  37 . A second end cap  12  is then arranged in coaxially confronting relation to first end  13  such that open end edge  46  is positioned adjacent to opening  14 . Once in this position end cap  12  is moved toward tube  10  so that open end edge  46  enters tube  10  until snap-rib  45  engages the recess  30  adjacent to the end tube  10 . As this occurs, brim  47  engages the open end edge of first end  13 .  
         [0031]    Tubular sleeve assembly  5  is used during the manufacture of a precast concrete structure  8 , to create a useable void in the structure, in the following manner. A form  50 , that comprises the shape of a structural element, e.g., a column, wall, stair, beam, riser, double tee, girder, spandrel beam, or floor slab, is filled with uncured concrete  52  in a conventional manner (FIG. 8). A plurality of reinforcing materials or pre-stressing cables or rods (not shown) may be positioned within form  50  so as to precondition the precast concrete structure  8 . Either prior to pouring of the uncured concrete, or while the concrete is still in a plastic state, one or more tubular sleeve assemblies  5  are positioned within concrete  52  at predetermined locations along the length, or through the width, of the forming structure. Advantageously, the length of tubular sleeve  5  may be adjusted to accommodate a wide variety of widths and thicknesses by cutting tube  10  along a score line  34  so as shorten the tube to a desired length (FIG. 10). Tube  10  may be cut to the appropriate length for the particular structural element being precast, and then sunk into concrete  52  within form  50 , or tube  10  may be cut to size once concrete  52  has cured to a more solid state.  
         [0032]    Tubular sleeve assembly  5 , with one or both end caps  12  assembled to it, are arranged within form  50  at the pre-selected locations so that either first end  13  or second end  20  stand proud of the surface of concrete  52 . As a result, central passageway  17  of tube  10  is isolated from concrete  52 . With end caps  12  in place, tubular sleeve assembly  5  is also protected from the environment so as to remain in a pristine configuration for final use during assembly of precast concrete structure  8 . When access is needed to central passageway  17 , end caps  12  are merely removed to open tube  10  for use.  
         [0033]    In one embodiment of the present invention, a precast concrete structure  54  may be lifted or otherwise moved by first removing end caps  12  from tube  10 , and inserting a steel rod  60  through central passageway  17  (FIG. 12). A pair of hooks or eyelets  65  are then clipped over the exposed ends of rod  60  followed by clamps  68  which are adapted to be releasably fastened onto rod  60  so as to hold hooks  65  in place. Once this construction is completed, a conventional hoist, crane, or other means for lifting heavy objects may be employed to grasp hooks  65  and move precast concrete structure  54  to an appropriate location. Once in location, releasable clamp  68  may be removed along with hooks  65  and steel rod  60  thus positioning precast concrete structure  54  in place. End caps  12  may or may not be replaced in tube  10  once precast concrete structure  54  is in it&#39;s final position.  
         [0034]    It is to be understood that the present invention is by no means limited only to the particular constructions herein disclosed and shown in the drawings, but also comprises any modifications or equivalents within the scope of the claims.