Abstract:
Forms utilized in constructing concrete structures and expansion joints utilized in concrete structures are formed from closed cell polymeric foam. The forms and expansion joints may comprise a single layer or multiple layers joined by heat sealing or by means or a suitable adhesive. A reinforcing layer comprising mesh or sheet material may be positioned between the layers comprising the form or expansion joint.

Description:
TECHNICAL FIELD  
         [0001]    This invention relates generally to the construction of concrete sidewalks, concrete driveways, and other concrete structures, and more particularly to improvements in the design and construction of forming systems and in the design and construction of expansion joints used in concrete construction.  
         BACKGROUND AND SUMMARY OF THE INVENTION  
         [0002]    The construction of concrete sidewalks, concrete driveways, and similar concrete structures typically involves the use of forms which are deployed along the opposite edges of the concrete structure to be formed. Reinforcing members, which may comprise re-bar, wire mesh, etc., are deployed between the forms. When the reinforcing members are in place, concrete is poured into the space between the forms and is allowed to cure. When curing is complete, the forms are removed and the concrete structure is ready for use.  
           [0003]    Heretofore the forms utilized in concrete construction have typically been manufactured from wood, with both conventional lumber and plywood having been used in the manufacture of concrete forms. Although generally satisfactory insofar as the end result is concerned, the use of wooden forms for concrete construction inherently includes numerous drawbacks. First, wooden concrete forms are heavy and therefore require the use of large trucks to transport the forms to and from the construction site, and further require the use of multiple personnel to transport the forms from the delivery point to the location at which they will actually be used. Second, due to environmental and other concerns, the cost of using wooden forms for concrete construction has risen steadily over the years. Third, saws, usually power saws, are required to cut wooden forms to length or otherwise adapt wooden forms to particular applications.  
           [0004]    The present invention comprises a method of and apparatus for concrete forming which overcomes the foregoing and other difficulties which have long since been associated with the prior art. In accordance with the broader aspects of the invention, concrete forms are formed from closed cell polymeric material. Concrete forms constructed in accordance with the invention weigh between about one fifth and about one tenth as much as wooden concrete forms, meaning that pickup trucks and similar light duty vehicles can be utilized to transport the concrete forms to the building site, and a single individual can carry a large number of the forms from the delivery site to the point of construction. Additionally, concrete forms constructed in accordance with the invention can be cut to length using pocket knives or similar cutting instruments thereby substantially improving the efficiency of concrete form construction.  
           [0005]    The construction of concrete sidewalks, driveways, and similar concrete structures also involves the use of expansion joints which are positioned at spaced apart intervals along the length of the concrete structure to allow for thermal expansion, etc. Heretofore expansion joints have been formed from wood, plastic, and other natural and synthetic materials. In accordance with the present invention expansion joints utilized in concrete construction are formed from closed cell polymeric foam materials. Expansion joints comprising the present invention are both more economical to use and easier to install as compared with prior art expansion joint designs.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    A more complete understanding of the present invention may be had by reference to the following Detailed Description when taken in connection with the accompanying Drawings, wherein:  
         [0007]    [0007]FIG. 1 is a partial perspective view illustrating a first embodiment of the invention;  
         [0008]    [0008]FIG. 2 is a side view illustrating a second embodiment of the invention in which certain parts have been broken away more clearly to illustrate certain features of the invention;  
         [0009]    [0009]FIG. 3 is a side view similar to FIG. 2 illustrating a third embodiment of the invention in which certain parts have been broken away to more fully illustrate certain features of the invention;  
         [0010]    [0010]FIG. 4 is a partial perspective view illustrating a fourth embodiment of the invention;  
         [0011]    [0011]FIG. 5 is a partial perspective view illustrating the fifth embodiment of the invention;  
         [0012]    [0012]FIG. 6 is a partial perspective view illustrating the method and apparatus of the present invention; and  
         [0013]    [0013]FIG. 7 is a partial perspective view illustrating the method and apparatus of the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0014]    Referring now to the Drawings, and particularly to FIG. 1 thereof, there is shown a section of concrete forming material  10  comprising a first embodiment of the invention. The section of concrete forming material  10  comprises closed cell foam formed from a polymeric material. The polymeric material utilized in the manufacture of the concrete forming material  10  may be polyethylene, polypropylene, mixtures or blends of polyethylene and polypropylene, polystyrene, or any other selected polymeric material depending upon the requirements of particular applications of the invention.  
         [0015]    The section of concrete forming material  10  has a predetermined thickness T which typically is about ½ inch. The section of concrete forming material  10  further comprises a predetermined height H. When the section of concrete forming material  10  is intended for utilization in the construction of concrete sidewalks the height H will typically be about four inches or more. When the section of concrete forming material  10  is intended for utilizing the construction of driveways the height H will typically be about six inches or more. When the section of concrete forming material  10  is intended for utilization and construction of other concrete structures, the height H will depend upon the dimensions of the concrete structure to be formed.  
         [0016]    An important consideration in determining the thickness T and the height H of concrete forms comprising the present invention is the fact that when oriented to stand upright on one of the narrow edges thereof the forms must have sufficient rigidity to support a screed of the type used in concrete construction. As is well known to those skilled in the art, a screed is a device used to smooth and level the upper or outer surface of a quantity of concrete following pouring and prior to curing thereof. The requirement that concrete forms constructed in accordance with the invention have sufficient rigidity to support the screed during smoothing and leveling of concrete contained by the forms is common to all embodiments of the invention.  
         [0017]    The section of concrete forming material  10  further comprises a length L which is not critical to the practice of the invention but typically is ten feet, twelve feet, or more. As will be apparent to those skilled in the art, the length L of the section of concrete forming material  10  ultimately depends upon the requirements of particular applications of the invention.  
         [0018]    As will be apparent from FIG. 1, the section of concrete forming material  10  comprises a unitary layer. In some instances the construction of concrete forming material incorporating the invention in the form of a single layer may be problematic. Referring to FIG. 2, there is shown a section of concrete forming material  12  comprising a two layer construction. The length of concrete forming material  12  is substantially identical to the length of concrete forming material  10  of FIG. 1 except that it comprises two layers.  
         [0019]    In the construction of the section of concrete forming material  12  a hot air knife  14  is positioned between the layers  16  and  18 . Each of the layers  16  and  18  is comprised entirely of closed cell polymeric foam. For example, the layers  16  and  18  may comprise closed cell polyethylene foam, closed cell polypropylene foam, etc. depending upon the requirements of particular embodiments of the invention.  
         [0020]    The hot air knife  14  heats the adjacent surfaces of the layers  16  and  18  to the melting point, or at least sufficiently to cause substantial softening thereof. The layers  16  and  18  then pass between rollers  20  and  20 ′ whereby the layers  16  and  18  are permanently joined one to another to form the section of concrete forming material  12 . Upon joinder of the layers  16  and  18  the section of concrete forming material  12  is substantially identical to the section of concrete forming material  10  of FIG. 1 except that the existence of the bonding layer formed between the layers  16  and  18  under the action of the hot air knife  14  may impart additional resistance to bending to the section of concrete forming material  12  as compared with the section of concrete forming material  10 .  
         [0021]    Referring to FIG. 3, there is shown a section of concrete forming material  22  comprising a two layer construction. The length of concrete forming material  22  is substantially identical to the length of concrete forming material  10  of FIG. 1 except that it comprises two layers.  
         [0022]    In the construction of the section of concrete forming material  22  a nozzle  24  is positioned between the layers  26  and  28 . Each of the layers  26  and  28  is comprised entirely of closed cell polymeric foam. For example, the layers  26  and  28  may comprise closed cell polyethylene foam, closed cell polypropylene foam, etc. depending upon the requirements of particular embodiments of the invention.  
         [0023]    The nozzle  24  deposits an adhesive A on the adjacent surfaces of the layers  26  and  28 . The layers  26  and  28  then pass between rollers  30  and  30 ′ whereby the layers  26  and  28  are permanently joined one to another to form the section of concrete forming material  22 . Upon joinder of the layers  26  and  28  the section of concrete forming material  22  is substantially identical to the section of concrete forming material  10  of FIG. 1 except that the existence of the bonding layer formed between the layers  26  and  28  under the action of the adhesive A may impart additional resistance to bending to the section of concrete forming material  22  as compared with the section of concrete forming material  10 .  
         [0024]    Referring to FIG. 4 there is shown a section of concrete forming material  42  comprising a fourth embodiment of the invention. The section of concrete forming material  42  comprises a two layer construction which is similar in many respects to the section of concrete forming material  12  illustrated in FIG. 2 and described hereinabove in conjunction therewith and to the section of concrete forming material  22  shown in FIG. 3 and described hereinabove in conjunction therewith.  
         [0025]    The section of concrete forming material  42  differs from the section of concrete forming material  12  and the section of concrete forming material  22  in that it includes a reinforcing layer  44 . The reinforcing layer  44  may comprise a mesh formed from metal, an elastomeric material, fiberglass, etc. depending upon the requirements of particular applications of the invention. The section of concrete forming material  42  further comprises opposed layers  46  and  48  each formed from a closed cell polymeric foam which may comprise polyethylene foam, polypropylene foam, etc. depending upon the requirements of particular applications of the invention.  
         [0026]    The layers  46  may be joined one to another with the layer  44  sandwiched therebetween by an adhesive A discharged from a nozzle  50  in the manner illustrated in FIG. 3 and described hereinabove in conjunction therewith. Alternatively, the section of concrete forming material  42  may be formed by securing the layers  46  and  48  one to another with the layer  44  sandwiched therebetween utilizing a hot air knife as illustrated in FIG. 2 and described hereinabove in conjunction therewith.  
         [0027]    Referring to FIG. 5 there is shown a section of concrete forming material  52  comprising a fourth embodiment of the invention. The section of concrete forming material  52  comprises a two layer construction which is similar in many respects to the section of concrete forming material  12  illustrated in FIG. 2 and described hereinabove in conjunction therewith and to the section of concrete forming material  52  shown in FIG. 3 and described hereinabove in conjunction therewith.  
         [0028]    The section of concrete forming material  52  differs from the section of concrete forming material  12  and the section of concrete forming material  22  in that it includes a reinforcing layer  54 . The reinforcing layer  54  may comprise a sheet formed from metal, an elastomeric material, fiberglass, etc. depending upon the requirements of particular applications of the invention. The section of concrete forming material  52  further comprises opposed layers  56  and  58  each formed from a closed cell polymeric foam which may comprise polyethylene foam, polypropylene foam, etc. depending upon the requirements of particular applications of the invention. The layers  56  may be joined one to another with the layer  54  sandwiched therebetween by an adhesive A discharged from a nozzle  50  in the manner illustrated in FIG. 3 and described hereinabove in conjunction therewith. Alternatively, the section of concrete forming material  52  may be formed by securing the layers  56  and  58  one to another with the layer  54  sandwiched therebetween utilizing a hot air knife as illustrated in FIG. 2 and described hereinabove in conjunction therewith.  
         [0029]    The manufacturing techniques illustrated in FIGS. 1 through 5, inclusive, and described hereinabove in conjunction therewith may also be utilized in the manufacture of expansion joints for concrete structures. The expansion joints are substantially identical in construction and function to the sections of concrete forming material described hereinabove except that the length of the expansion joints is typically substantially less than the lengths of the sections of concrete forming material. The expansion joints of the present invention may be provided either in a selected of predetermined lengths, or they may be easily cut to length in the field utilizing pocket knives and similar cutting instruments.  
         [0030]    Referring to FIG. 6, there is shown a concrete structure C which is constructed utilizing forms  66  and expansion joints  68  manufactured in accordance with the present invention. The forms  66  may be formed as illustrated in FIG. 1 and described hereinabove in conjunction therewith, or as illustrated in FIG. 2 and described hereinabove in conjunction therewith or as illustrated in FIG. 3 and described hereinabove in conjunction therewith, or as illustrated in FIG. 4 and described hereinabove in conjunction therewith, or as illustrated in FIG. 5 and described hereinabove in conjunction therewith. Regardless of the technique which is utilized in the manufacture of the forms  66 , the forms  66  has sufficient flexibility to adapt readily to the construction of concrete structures which are curvilinear in shape. Alternatively, the forms  66  may be utilized to construct a concrete structure having sides which are straight and parallel. In either event the concrete forms  66  are retained in place by retaining members  70  formed from wood, plastic, metal or the like which are driven into the underlying surface S in the conventional manner.  
         [0031]    As indicated hereinabove, the expansion joints  68  of the concrete construction C may be fabricated as illustrated in FIG. 1 and described hereinabove in conjunction therewith, or as illustrated in FIG. 2 and described hereinabove in conjunction therewith, or as illustrated in FIG. 3 and described hereinabove in conjunction therewith, or as illustrated in FIG. 4 and described hereinabove in conjunction therewith, or as illustrated in FIG. 5 and described hereinabove in conjunction therewith. As will be appreciated by those skilled in the art, the expansion joints  68  typically extend perpendicularly to the forms  66  and are positioned at spaced apart intervals along the length of the concrete construction C.  
         [0032]    Referring to FIG. 7, concrete forms  72  may be utilized in the construction of the concrete foundation slab F which in many instances will be substantially thicker than a sidewalk or a driveway. Also, the concrete foundation slab F is typically rectilinear in shape and is characterized by straight sides extending perpendicularly to one another. The concrete forms  72  of the present invention utilized in the construction of the foundation slab F may be manufactured as illustrated in FIG. 1 and described hereinabove in conjunction therewith, or as illustrated in FIG. 2 and described hereinabove in conjunction therewith, or as illustrated in FIG. 3 and described hereinabove in conjunction therewith, or as illustrated in FIG. 4 and described hereinabove in conjunction therewith, or as illustrated in FIG. 5 and described hereinabove in conjunction therewith. In any event, the concrete forms  72  are typically retained in place by spikes or stakes  74  which may be formed from wood, plastic, metal, or any other desired material and which are typically driven into the underlying surface to retain the forms  72  in place which the concrete comprising the foundation slab F is poured and cured.  
         [0033]    Although preferred embodiments of the invention have been illustrated in the accompanying Drawings and described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions of parts and elements without departing from the spirit of the invention.