Abstract:
A system and method are provided for forming expansion joints within artificial ground cover. An elongated expansion joint support is coupled with a length of expansion joint material. A lower end portion of the expansion joint support is shaped to engage a ground surface. The two structures may be coupled with one another in different positions to vary the resulting expansion joint height. The lower end portion of the expansion joint support may be shaped to have a ground engagement wall and to receive ground engagement spikes. No component parts need be removed from the system after the application of artificial ground cover adjacent thereto, thus permitting simultaneous application of ground cover on both sides of the expansion joint.

Description:
BACKGROUND 
   Expansion joints are commonly found in various forms of artificial ground cover, including concrete forms such as sidewalks, driveways and other slab structures. Expansion joints may also be used in other forms of ground cover that may be comprised of masonry, various metals, and other such materials that are prone to expansion and contraction throughout seasonal temperature changes. The expansion joints help to cushion the effect of expansion and contraction, thus preventing cracking, heaving and other such ill effects. 
   Expansion joints are typically formed from durable, resiliently deformable materials. Fiber-board is an example of one common expansion joint material which is formed from natural and man-made fibers that are bonded together using asphalt or other known bonding agents. Other expansion joint materials include closed-cell polyfoam, rubber, cork, cross-linked ethylene vinyl acetate and closed-cell neoprene. The expansion joint material selected may depend upon various factors presented in each particular application. Some factors may include cost, climate and type of material used in the formation of the artificial ground cover. Regardless of their construction, expansion joint materials are typically formed to have a thickness that ranges between ¼ of an inch to 1 inch. Common widths range from 3 inches to 12 inches and their lengths are commonly found in four to ten foot sheets. 
   Commonly, expansion joint material is positioned adjacent an existing section of ground cover, such as concrete, prior to applying new ground cover immediately adjacent thereto. In instances where expansion joint material is to be positioned in an area where no existing ground cover exists, contractors typically position ½″×4″ or 1″×4″ backboard behind the expansion joint material and stake the backboard in place. The new ground cover is then applied over the ground surface adjacent the expansion joint material. Once the ground cover has sufficiently cured, the backboard and stakes are removed and the next section of ground cover may be applied to the ground surface, adjacent the opposite side of the expansion material. This method of forming an expansion joint has several shortcomings. First, the ground cover is applied to the ground surface in multiple stages over a period of two or more days. The increased number of trips to and from a job-site become time consuming and expensive over time. Secondly, as depicted in  FIG. 2 , expansion joint material is frequently provided in widths that are insufficient to span the full thickness of the ground cover being applied. Accordingly, as the ground cover is applied to the ground surface adjacent the expansion joint material, the ground cover will not be segregated from adjacent, existing ground cover. This results in the two sections of ground cover being abutted immediately adjacent one another and defeats the purpose of installing an expansion joint at this location. In other instances, also depicted in  FIG. 2 , the ground surface is improperly prepared, leaving depressions or other recesses at the location where an expansion joint is required. In these instances, expansion joint material that would otherwise be of sufficient width for the thickness of ground cover being applied will be insufficient to span the distance from the bottom of the depression to the surface of the ground cover being applied. The result will produce a single section of ground cover without the appropriate expansion joint structure. 
   Accordingly, what is needed is a novel system and method for forming expansion joints that enables a user to prepare an entire site for a single pour or application of artificial ground cover. Such a novel system and method should also enable a user to vary the vertical positioning of expansion joint material in a given location while effectively segregating adjacent sections of ground cover. 
   SUMMARY 
   This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key aspects or essential aspects of the claimed subject matter. Moreover, this Summary is not intended for use as an aid in determining the scope of the claimed subject matter. 
   A system and method are provided for forming at least one expansion joint in artificial ground cover. An elongated expansion joint support is provided with at least one outer surface, an upper end portion and a lower end portion. The lower end portion of the expansion joint support is shaped to operatively engage the ground surface. A length of expansion joint material, having an upper end portion and a lower end portion, is operatively coupled with the expansion joint support so that at least a portion of the upper end portion of the expansion joint material extends along but beyond the upper end portion of the expansion joint support. The lower end portion of the expansion joint support is then operatively coupled with the ground surface. Ground cover may then be applied over the ground surface closely adjacent the outer surface of the expansion joint support and the expansion joint material. 
   In one aspect of the invention, fasteners may be used to extend inwardly from the expansion joint support to secure the expansion joint material therewith. The expansion joint material may be secured with the expansion joint support at various positions along the width of the expansion joint support in order to selectively space the upper end portion of the expansion joint material from the upper end portion of the expansion joint support. In another aspect of the invention, a plurality of openings may be formed in the lower end portion of the expansion joint support so that spikes may be passed through the openings and into the ground surface to operatively secure the expansion joint support with the ground surface. 
   In another aspect of the invention, the lower end portion of the expansion joint support may be shaped to have a ground engagement wall that extends generally perpendicularly with respect to the remainder of the expansion joint support. The ground engagement wall may extend laterally beyond the sides of the expansion joint support to stabilize the same on the ground surface. The ground engagement wall may also terminate flush with a side of the expansion joint support to provide a close fit adjacent existing ground cover. 
   One preferred aspect of the invention provides the expansion joint support with a pair of generally parallel, spaced-apart support walls that extend upwardly from the lower end portion of the expansion joint support. The expansion joint material may be secured between the support walls of the expansion joint support. 
   It is therefore a principal object of the present invention to provide a system and method of forming expansion joints in artificial ground cover that permits non-staged, single application of ground cover material adjacent both sides of the expansion joint. 
   A further object of the present invention is to provide a system and method of forming expansion joints in artificial ground cover that permits a user to vary the height of an expansion joint while effectively segregating adjacent sections of ground cover. 
   Still another object of the present invention is to provide a system and method of forming expansion joints in artificial ground cover that effectively supports expansion joint material in place during the application of new ground cover to the ground surface. 
   Yet another object of the present invention is to provide a system and method of forming expansion joints in artificial ground cover that does not require the removal of support structure adjacent the expansion joint after the application of ground cover material adjacent the ground surface and the expansion joint material. 
   A further object of the present invention is to provide a system and method of forming expansion joints in artificial ground cover that is relatively simple and inexpensive to manufacture. 
   Still another object of the present invention is to provide a system and method of forming expansion joints in artificial ground cover that is relatively quick and simple to use. 
   These and other objects of the present invention will be apparent after consideration of the Detailed Description and Figures herein. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
       FIG. 1  depicts a perspective view of a driveway after the application of one preferred expansion joint system of the present invention but prior to the application of new ground cover material; 
       FIG. 2  depicts improperly formed expansion joints that frequently occur when prior art systems and methods of forming expansion joints are implemented; 
       FIG. 3  depicts a side elevation view of one preferred expansion joint system as the same could be incorporated among different sections of artificial ground cover; 
       FIG. 4  depicts a partially exploded, isometric view of one preferred expansion joint system of the present invention; and 
       FIG. 5  depicts a sectional, isometric view of one preferred expansion joint system as the same could be used in preparing a ground surface to receive a section of artificial ground cover adjacent an existing section of artificial ground cover. 
   

   DETAILED DESCRIPTION 
   Embodiments are described more fully below with reference to the accompanying figures, which form a part hereof and show, by way of illustration, specific exemplary embodiments. These embodiments are disclosed in sufficient detail to enable those skilled in the art to practice the invention. However, embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. The following detailed description is, therefore, not to be taken in a limiting sense in that the scope of the present invention is defined only by the appended claims. 
   The expansion joint system  10  of the present invention is generally provided with an elongated expansion joint support  12 , having an upper end portion  14  and a lower end portion  16 . The lower end portion  16  is preferably shaped to operatively engage a ground surface  18 . In one preferred embodiment, the lower end portion  16  is shaped to have a plurality of openings  20  that are spaced along the length of the expansion joint support  12 . The openings  20  are shaped and sized to receive a plurality of spikes  22  (or other similar form of fastener) therethrough, such that the spikes  22  engage the ground surface  18  and secure the lower end portion  16  of the expansion joint support  12  thereto.  FIGS. 3 and 4  depict possible configurations of the openings  20  and spikes  22  and at least one manner in which the same may be employed. In another preferred embodiment, the lower end portion  16  of the expansion joint support  12  is shaped to have a ground engagement wall  24  that extends generally perpendicularly with respect to the remainder of the expansion joint support  12 . As depicted in  FIG. 3 , it is contemplated that the ground engagement wall  24  may extend outwardly from a first outer surface  26  and an opposite, second outer surface  28  of the expansion joint support  12 . This arrangement provides the expansion joint support  12  with an increased degree of stability that permits the expansion joint support  12  to remain in an upright, free-standing position. However,  FIG. 3  also depicts another preferred embodiment wherein the ground engagement wall  24  extends outwardly from only one of the outer surfaces of the expansion joint support  12 , forming a lower corner portion  30 , which may be positioned closely adjacent the ground surface  18  and the generally vertical face of an existing section of ground cover  32 . As discussed in greater detail herein below, this arrangement permits the formation of an expansion joint closely adjacent the existing section of ground cover  32 . 
   The expansion joint system  10  is further provided with a length of expansion joint material  34 , having an upper end portion  36  and a lower end portion  38 . It is contemplated that the expansion joint material  34  may be comprised of nearly any material suitable for use in forming expansion joints. Variation from one material to the next in forming the expansion joint material  34  will not greatly affect the use or performance of the expansion joint system  10  as the expansion joint system  10  is constructed to be adaptable for use in nearly any environment and with nearly any type of artificial ground cover. 
   In use, the expansion joint support  12  is coupled with the expansion joint material  34  so that at least a portion of the upper end portion  36  of the expansion joint material  34  extends along but beyond the upper end portion  14  of the expansion joint support  12 .  FIG. 4  depicts one preferred embodiment of the expansion joint support  12  wherein a first support wall  40  and second support wall  42  extend upwardly from the lower end portion  16  of the expansion joint support  12  so that the first and second support walls  40  and  42  are positioned in a generally parallel, spaced-apart relationship with one another. This orientation permits at least the lower end portion  38  of the expansion joint material  34  to be received between the first support wall  40  and the second support wall  42 . To that end, the first support wall  40  and second support wall  42  may be positioned to be spaced apart from one another by a distance that is slightly smaller than the thickness of the expansion joint material provided. This arrangement provides a degree of friction fit between the expansion joint material  34  and the expansion joint support  12 , securing a user selected position of the two structures with respect to one another. Slightly biasing the upper end portions of the first support wall  40  and second support wall  42  would provide a similar effect. It is also contemplated that the expansion joint support  12  could be formed to have only one support wall extending upwardly from the lower end portion  16 . Regardless of whether one or more support walls are provided, the expansion joint material  34  may be operatively secured with the expansion joint support  12  using a plurality of fasteners  44  that extend inwardly from at least one of the support walls in the expansion joint support  12 . It is contemplated that the fasteners  44  may be provided in the form of integral teeth members or a plurality of separate fasteners  44  that are passed through openings  46  formed through at least one of the support walls of the expansion joint support  12 . As depicted in  FIG. 4 , the openings  46  may be provided at different selectable positions between the upper end portion  14  and the lower end portion  16  of the expansion joint support  12 . This will permit the upper end portion  36  of the expansion joint material  34  to be positioned at different heights relative to the upper end portion  14  of the expansion joint support  12 , thus providing an expansion joint system  10  that is capable of being installed in various selectable heights according to the circumstances presented. For example, the instances depicted in  FIG. 2  could easily be remedied by the expansion joint system  10 , wherein the height of the expansion joint material  34  could be increased relative to the expansion joint support  12  so that the expansion joint system  10  would extend to the ground surface  18 . 
   Once the expansion joint material  34  is coupled with the expansion joint support  12 , the system  10  may be placed in position closely adjacent the ground surface  18 . It will be desirable to position a length of the expansion joint system  10  closely adjacent any pre-existing ground surface sections  32 , as depicted in  FIG. 1 . However, the expansion joint system  10  provides a level of flexibility that permits positioning of an expansion joint intermediate new sections of ground cover  48  that are to be installed in a single application or pour. In the example depicted in  FIG. 1 , wherein the chosen ground cover is concrete, the expansion joint system  10  permits the user to pour the driveway section and the approach section at one time. 
   Irrespective of whether the expansion joint system  10  is to be used adjacent existing sections of ground cover  32  or intermediate new sections of ground cover  48 , it will simply be desirable to form a barrier that extends from the ground surface  18  to a point near the desired upper surface of the new section of ground cover  48 . In this manner, the barrier formed by the expansion joint support  12  and the expansion joint material  34  substantially prevents the passage of new ground cover material past the expansion joint system  10 . This will prevent the comingling of adjacent sections of ground cover and create the desired expansion joint. Accordingly, any openings formed through the expansion joint system  10 , such as the openings  46 , should be shaped and sized so that a minimal amount of ground cover material would enter or pass therethrough. 
   While it is contemplated that the expansion joint support  12  and other structures utilized within the expansion joint system  10  could be comprised of nearly any material, it is preferable to form each of the components from materials that may be left in position, beneath the surface of the ground cover, indefinitely. This will further reduce installation time by reducing the number of forms and other structural devices that are typically removed from the site once the ground cover has cured. However, it is contemplated that it may be desirable to form the expansion joint support  12  from a material that is at least slightly flexible, such that the expansion joint support  12  itself functions in a manner similar to the expansion joint material  34  by deforming slightly in response to the expansion of adjacent ground cover. 
   Although the invention has been described in language that is specific to certain structures and methodological steps, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific structures and/or steps described. Rather, the specific aspects and steps are described as forms of implementing the claimed invention. Since many embodiments of the invention can be practiced without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.