Abstract:
A plastic pipe coupler is provided having a plurality of sections connected to one another but with at least one gap between the ends of two sections which are adjacent to one another, at least two brackets, concrete pipe fastening means, and connector elements. Each of the coupler sections has an exterior surface and an interior surface, and is fabricated so that when taken together, the sections cooperatively circumvent a section of plastic pipe, preferably corrugated. Each bracket is secured to the exterior surface of one of the aforesaid sections of the coupler and has a base plate, a pair of sidewall plates attached to each base plate, and a crosspiece having a first end and a second end, the first end of which is in contacting relationship with one of the pair of sidewall plates, while the second end is in contacting relationship with the other of the pair of sidewall plates. The connecting element has a first end portion secured to the concrete pipe fastening means and a second end portion secured to the bracket, preferably to the crosspiece.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates generally to couplers, and more particularly, to a coupler that can mechanically join together a plastic pipe and a concrete pipe, and still more particularly a plastic pipe that is corrugated. 
         [0003]    2. Description of the Related Art 
         [0004]    This invention is directed to the providing of a coupler for use with plastic and concrete pipe. Over the years, there have been many couplers for joining one plastic pipe with another pipe also made from plastic. Similarly, there have been couplers that have been made to join together two pipes fabricated from concrete. However, there has never been a coupler that can mechanically join together a concrete pipe having a smooth-walled exterior and a plastic pipe, especially one that is corrugated. 
         [0005]    Historically, concrete and plastic pipes have not been used together in the field due to the absence of mechanical connectors. Attempts at using the screw-type of coupler used with concrete pipe on plastic pipe as well could result in the tearing of the plastic pipe if the juncture of the two pipes was subjected to stress. Additionally, many job applications only permitted the use of one type of pipe, however, recently there has been some willingness on the part of some organizations charged with overseeing transportation related pipe installations to permit concrete and plastic pipe to be used in the same job installation. 
         [0006]    For example, one place historically where only concrete pipe has been used is in culvert applications beneath roadways. Cylindrical, smooth-walled concrete pipe typically 8′ in length is laid well beneath the road surface, extending from one side of the road to the other. Penultimate sections of concrete pipe are laid at opposing ends of the concrete pipe(s), with concrete culvert openings attached to the opposite free ends of the concrete conduit. Each of the concrete structures is coupled to the structure adjacent thereto using couplers well known in the concrete pipe industry. The installation process is time consuming and requires the use of manpower and equipment sufficient to move such heavy structures. By using HDPE (high density polyethylene) or other types of plastic pipe with similar characteristics to HDPE, the manpower and equipment requirements could possibly be lessened. Additionally, a longer plastic pipe (greater than 12′ and normally 20′ in length) could be utilized in place of several shorter concrete sections due to the weight factor. This could further reduce installation time and decrease the number of joints, thereby decreasing the number of joint leaks, as well as being cheaper due to the relative costs of the pipes involved. 
         [0007]    It is thus apparent that the need exists for a coupler for mechanically joining concrete and plastic pipe which effectuates a watertight seal so as to be useful in culvert construction, which coupler is relatively easy to fabricate and cost effective to use. 
       SUMMARY OF THE INVENTION 
       [0008]    In accordance with the present invention, there is disclosed a plastic pipe coupler having a plurality of sections connected to one another but with at least one gap between the ends of two sections which are adjacent to one another, at least two brackets, a concrete pipe fastening means, and a connector element. Each of the coupler sections has an exterior surface and an interior surface, and is fabricated so that when taken together, the sections cooperatively surround a ringed section of plastic pipe having a first outer diameter, with each interior surface associated with each section being directly adjacent the plastic pipe of a first outer diameter. 
         [0009]    Each bracket is secured to the exterior surface of one of the aforesaid sections of the coupler adjacent a section of the coupler to which another bracket is secured. Each of the brackets has a base plate, a pair of sidewall plates attached to each base plate, and a crosspiece having a first end and a second end. The first end of each crosspiece is in contacting relationship with one of the pair of sidewall plates, while the second end of each crosspiece is in contacting relationship with the other of the pair of sidewall plates. 
         [0010]    The concrete pipe fastening means engages a concrete pipe of a second outer diameter. The connecting element has a first end portion secured to the concrete pipe fastening means and a second end portion secured to the bracket, preferably to the crosspiece. 
         [0011]    Preferably each section is corrugated such that it has a plurality of crowns and troughs. Some of the adjacent sections are connected to each other by hinge means, with the sections being of a first thickness and the hinge means being of a second thickness, with the first thickness being greater than the second thickness. 
         [0012]    Each base plate is preferably welded to the exterior surface of the section of the coupler to which it is secured. Additionally, each base plate may be further secured to its respective section by fastening means which pass through apertures formed in the base plate, if these additional fastening means are used, as well as through the plastic pipe. Each base plate has an upper surface and a lower surface, with the lower surface being directly adjacent the coupler section. The upper surface of each base plate has sidewall plates, preferably two in number, projecting upwardly therefrom. 
         [0013]    Each of the sidewall plates has a slot formed therein, with the crosspiece having its opposite ends retained in the respective slot. The crosspiece has a longitudinal axis and the base plate has a longitudinal axis, with the longitudinal axis of the crosspiece being generally perpendicular to the longitudinal axis of the base plate. The crosspiece has an aperture formed therein. The crosspiece has a first surface facing towards the concrete pipe fastening means and a second surface facing away from the concrete pipe fastening means. The connecting element passes through the crosspiece aperture. The connecting element second end portion is secured with fastening means directly adjacent the second surface of the crosspiece. 
         [0014]    Additionally, preferably at least one coupler section has an aperture formed therein, with that aperture having fastening means passing therethrough as well as through the sidewall of the plastic pipe of the first outer diameter. This additional fastening means provides yet another securing of the section to the plastic pipe of a first outer diameter. 
         [0015]    There is also disclosed a split coupler component of the coupling of a concrete pipe to a plastic pipe with the split coupler having a plurality of sections connected to one another but with at least one gap between the ends of two sections which are adjacent to one another, and at least two brackets. Each of the coupler sections has an exterior surface and an interior surface, and is fabricated so that when taken together, the sections cooperatively surround a corrugated plastic pipe. 
         [0016]    Each bracket is secured to the exterior surface of one of the aforesaid sections of the coupler adjacent a section of the coupler to which another bracket is secured. Each of the brackets has a base plate, a pair of sidewall plates attached to each base plate, and a crosspiece having a first end and a second end. The first end of each crosspiece is in contacting relationship with one of the pair of sidewall plates, while the second end of each crosspiece is in contacting relationship with the other of the pair of sidewall plates, and with the crosspiece having an aperture therein. 
         [0017]    Preferably each section is corrugated such that it has a plurality of crowns and troughs. Some of the adjacent sections are connected to each other by hinge means, with the sections being of a first thickness and the hinge means being of a second thickness, with the first thickness being greater than the second thickness. 
         [0018]    Each base plate is preferably welded to the exterior surface of the section of the coupler to which it is secured. Additionally, each base plate may be further secured to its respective section by fastening means which pass through apertures formed in the base plate, if these additional fastening means are used, as well as through the plastic pipe. Each base plate has an upper surface and a lower surface, with the lower surface being directly adjacent the coupler section. The upper surface of each base plate has sidewall plates, preferably two in number, projecting upwardly therefrom. 
         [0019]    Each of the sidewall plates has a slot formed therein, with the crosspiece having its opposite ends retained in the respective slot. The crosspiece has a longitudinal axis and the base plate has a longitudinal axis, with the longitudinal axis of the crosspiece being generally perpendicular to the longitudinal axis of the base plate. 
         [0020]    The primary objective of this invention is to provide a coupler that can be used to mechanically join concrete pipe to plastic pipe. 
         [0021]    Another objective of this invention is to provide such a coupler that is able to be fabricated using existing technology and easily installed in operative position on the two pipes to be joined. 
         [0022]    Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a perspective view of a main portion of a coupler made in accordance with the present invention. 
           [0024]      FIG. 2  is a front elevational view taken from in front of  FIG. 1 . 
           [0025]      FIG. 3  is a front elevational view on an enlarged scale taken along line  3 - 3  of  FIG. 2 . 
           [0026]      FIG. 4  is a perspective view of the bracket component of the invention. 
           [0027]      FIG. 5  is a front elevational view of the crosspiece component of the invention. 
           [0028]      FIG. 6  is a top plan view of the base plate component of the invention. 
           [0029]      FIG. 7  is a vertical sectional view taken along line  7 - 7  of  FIG. 6 . 
           [0030]      FIG. 8  is a perspective view of the coupler of the invention shown in an operative embodiment. 
           [0031]      FIG. 9  is a vertical sectional view on a greatly enlarged scale taken along line  9 - 9  of  FIG. 8 . 
           [0032]      FIG. 10  is a horizontal sectional view on a greatly enlarged scale taken along line  10 - 10  of  FIG. 8 . 
           [0033]      FIG. 11  is a perspective view on a greatly enlarged scale of the portion of the invention within line  11 - 11  of  FIG. 8 . 
           [0034]      FIG. 12  is a front elevational view on a greatly enlarged scale taken at the gap in the coupler shown in  FIG. 2 . 
       
    
    
       [0035]    In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific term so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0036]    Having reference to the drawings, attention is directed first to  FIG. 1 , which discloses the main portion of a coupler made in accordance with the invention designated generally by the numeral  10 . The coupler is primarily fabricated from plastic, such as HDPE (high density polyethylene) or other extrudable, injected, or molded plastics. As can be appreciated from a comparison of  FIGS. 1 and 8 , the coupler  10  is adapted to join a concrete pipe  11  having an outer wall  12  and inner wall  13  at end  14  to a plastic pipe  16  with the pipe being corrugated. Each pipe corrugation  17  has associated therewith a crown  18  and a valley or trough  19 . 
         [0037]    Securing the coupler  10  to the concrete pipe  11  is accomplished by a concrete anchor  20  as can be appreciated by a comparison of  FIGS. 8 and 9 . The concrete anchor  20  is of the type well known in the art of concrete pipe, with the anchor being inserted through the concrete pipe from the outside thereof, and held in place adjacent to the interior wall  13  of the pipe using a washer  21   a  and nut  21   b , with the nut typically being a hex nut. The concrete anchor  20  passes through a concrete pipe fastener channel  22  which is drilled through the sidewall of the concrete pipe  11 . 
         [0038]    The concrete pipe anchor  20  has an aperture formed in the portion of the anchor which remains outside of the concrete pipe, with this aperture having passed therethrough a rod  24 , preferably threaded, or at least preferably threaded at each end. As can be seen in  FIG. 8 , it is this rod which provides connection between the anchor  20  on the concrete pipe and the bracket  25  on the portion of the coupler  10  which is secured to the plastic pipe  16 . The rod could be fabricated from metal or plastic, the advantage of plastic being that it is corrosion resistant. 
         [0039]    The coupler  10  as can be appreciated from a comparison of  FIGS. 1 ,  2 ,  3 , and  8  is of the type of coupler known as a split coupler  30 , meaning that while some if not almost all of the various sections  32  have hinged interconnection portions  33  between directly adjacent sections  32 , at least two directly adjacent sections have free ends  34  and  35  respectively such that a gap  36  exists therebetween. The number of sections chosen depends on how small the diameter of the plastic pipe is: the smaller the diameter, typically the fewer the sections. 
         [0040]    Each coupler corrugation is of a first thickness from the top of the crown to the bottom of the directly adjacent valley. Similarly each hinge portion of the split coupler is of a second thickness, with the first thickness being greater than the second thickness, thus creating flexibility at the hinged interconnection portion  33  which in reality is preferably a relatively planar portion of the coupler. The width of the hinge, namely the distance between the corrugations of adjacent sections of the coupler, may be several inches, thus resembling a generally rectangular area when the coupler is opened. The width depends in part on the diameter of the coupler when closed. By having hinge portions  33 , the split coupler  30  may be effectively opened and then closed to more easily encircle the pipe. 
         [0041]    The split coupler  30  also has coupler corrugations  37  with crowns  38  and valleys  39  connected by sidewalls  38   a . Thus, when the split coupler is closed around the plastic pipe, the coupler corrugations lay in the corrugations of the plastic pipe. The structure at the gap  36  can be better appreciated from a comparison of  FIGS. 1 ,  8 ,  11  and  12  in which the coupler is shown as having a pair of peripheral sidewalls  105  as the outermost of the sidewalls, with each peripheral sidewall  105  having a flange  103  extending perpendicularly therefrom along the bottom of the peripheral sidewall. The flange  103  also extends along the front and rear ends of the peripheral sidewall as well and has an edge  101  contiguous with the side edges of the free ends  34  and  35  respectively. 
         [0042]    As can best be appreciated from a comparison of  FIGS. 1 ,  11 , and  12 , the free ends  34  and  35  each have an end edge  110  and  111  respectively that extends between the aforementioned side edges of the free ends. The two free ends also have a top surface  112  and  113  respectively, each of which is preferably planar. The two free ends also have a bottom surface  114 ,  115  respectively, each of which is preferably planar and parallel to the respective top surfaces  112  and  113 . The two free ends each has a connecting surface  116  and  117  respectively substantially opposed to each other with connecting surface  116  extending between the bottom surface of free end  34  and interior surface  120  of the coupler, while connecting surface  117  extends between the bottom surface of free end  35  and interior surface  120  of the coupler. As is disclosed in the drawings, preferably the free ends overlap one another. Furthermore, it should be realized that as the coupler is extruded, by cutting at the portions of the extrudate which otherwise would constitute one of the hinged portions, the free ends are created. 
         [0043]    Still further, opposite ends of each valley on the exterior surface of the strip coupler also have a groove endwall  125  as can be seen in  FIG. 11 . Each groove endwall is thus located directly adjacent to each hinge member and each free end. Preferably, each groove endwall  125  has formed therein a groove aperture  126  which extends completely through the coupler substantially along the elongate axis of the valley. 
         [0044]    In the preferred embodiment of the invention, a band or strap  130  of polyethylene or other similar material is laid in one or more of the grooves in the coupler (e.g. one band is shown in each of the three grooves of the coupler shown in  FIG. 8 ) and inserted through each of the groove apertures  126  and finally secured to itself to form a supplemental band  130  around the coupler as can be appreciated from a comparison of  FIGS. 8 and 11 . Alternatively, the bands could just be laid in the grooves and made to pass beneath each of the brackets  25  before having the ends of the band secured to each other. 
         [0045]    A comparison of  FIGS. 1-8  better discloses the structure of bracket  25 . There are at least two brackets  25  utilized with the coupler  10  of this invention. Each bracket has a bracket base  50 , a pair of bracket sidewalls  52  and  54  respectively, and a bracket crosspiece  56 . 
         [0046]    The bracket base  50  has an upper surface  60  and a lower surface  62  and is shown as having at least one fastener aperture  64  drilled therethrough as in the embodiment where such fastening means are used. Each such fastener aperture  64  is located on the base such that the cooperating base fastener  65  inserted therethrough also passes through the crown  38  of the coupler corrugation  37 . Additionally, depending on the length of the bracket base  50 , there could be a plurality of fastener apertures  64  such as is depicted in  FIG. 6  where four are shown: one hole  64  for each directly adjacent coupler crown  38 . With respect to each cooperating base fastener  65 , it could be a nut and bolt or any other mechanical connection. The nuts could also be locking nuts. As shown in  FIGS. 2 and 3 , the head of the fastener is located adjacent the interior surface of the coupler corrugation in the valley thereof, with the shaft of the fastener extending outwardly through the split coupler and the bracket base where it is then fastened. In the preferred embodiment of the invention, the lower surface  62  of the bracket base  50  is adhesively secured or preferably welded  66  to the coupler crowns  38  on which it rests. 
         [0047]    The bracket base  50  also has edges  68  and ends  69 . The base is slightly curved as can be seen in  FIG. 7 , which also shows one fastener aperture  64  passing therethrough. This curvature is due to the curvature of the split coupler  30 , which is also curved to conform to the curvature of the plastic pipe over which the split coupler is laid. 
         [0048]    Extending upwardly from the bracket base, preferably from the upper surface thereof, are bracket sidewalls  52  and  54 , each having an interior surface  70  and an exterior surface  72 , the interior surfaces  70  facing each other. As can be appreciated from a comparison of  FIGS. 1 ,  2 , and  4 , each bracket sidewall has a bottom edge  73  which is directly adjacent the bracket base plate  50 . Each bracket sidewall is secured to the base  50 , preferably by weld  66  or equivalent means. 
         [0049]    Each bracket sidewall also has a side edge  74 , with the embodiment shown in the drawings also having a beveled side edge  75  which extends between the side edge  74  and the top edge  76  of the bracket sidewall. Extending downwardly from the top edge  76  of the two bracket sidewalls shown is a sidewall slot  77   a  and  77   b  respectively. The slot has opposing sidewalls  78  and a slot bottom surface  79 . While the opposing sidewalls  78  are shown as being essentially parallel to one another, it can be readily appreciated that in the preferred embodiment of the invention, the two bracket sidewalls are skewed with respect to each other as best shown in  FIG. 2 . 
         [0050]    Turning now to the crosspiece  56 , it can best be appreciated from a comparison of  FIGS. 1 ,  2 ,  4 ,  5 ,  8 , and  10 . It has a top edge  80  shown as being slightly arcuate, a bottom edge  82  shown as being parallel to the top edge  80 , front and rear sidewalls  83 , and side edges  84 . One of the sidewalls faces towards the concrete pipe to be joined. 
         [0051]    At least one crosspiece aperture  85  is located nearer the top edge  80  than to the bottom edge  82 , and approximately midway across the crosspiece. In  FIG. 5 , two crosspiece apertures are disclosed to enable a degree of adjustability. However, for most purposes it is believed that the closer the rod  24  is to the coupler and concrete pipe, the better. The thickness of the crosspiece is of a dimension slightly less than that of each of the slots in the bracket sidewalls. Thus, the first side edge portion of the crosspiece is retained in the slot of one of the bracket sidewalls while the second side edge portion of the crosspiece is retained in the slot on the opposite bracket sidewall. Preferably the crosspiece is further secured in the bracket by polyethylene welding of the crosspiece to the interior and exterior of both bracket sidewalls. 
         [0052]    The crosspiece has a longitudinal axis which extends from bracket sidewall to bracket sidewall, while the bracket base plate  50  has a longitudinal axis that extends in the direction of the longitudinal axis of the plastic pipe. Thus it will be recognized that the longitudinal axis of the crosspiece is essentially perpendicular to that of the base plate. The connecting element  24  is secured to the bracket as can be appreciated from a comparison of  FIGS. 8 and 10 . The connecting element extends through the crosspiece aperture  85 , with the threaded end of the connecting element being secured with washer  91   a  and nut  91   b , with the nut being adjacent the side of the crosspiece facing away from the concrete pipe joined by the coupler  10 . 
         [0053]    In actual use, the split coupler is closed about the plastic pipe. Typically the plastic pipe  16  is at least 12′ in length and often up to 20′ in length. A sealing gasket of the type known in the art of plastic pipe is placed on the outer surface of the plastic pipe so that upon insertion the gasket effects a fluid-tight seal. The plastic pipe then has its end inserted into the end aperture  14  of the concrete pipe  11  such that the split coupler is preferably located completely outside of the concrete pipe itself. 
         [0054]    The concrete anchor is positioned in the wall of the concrete pipe beyond the terminus of the inserted plastic pipe, so that the sealing gasket is between the concrete anchor and the end of the concrete pipe. The split coupler also may utilize fastening means  97  to secure at least one coupler section  32  to the plastic pipe  16  at aperture  95 . The purpose behind the use of fastening means  97  is to seat the split coupler onto the corrugated pipe. Although only one aperture  95  is shown, additional ones could be utilized to provide for more points of direct attachment between the pipe and the split coupler. The rod  24  between the reinforced concrete pipe and the plastic pipe provides additional means to secure the plastic pipe to the concrete one. 
         [0055]    During installation of the coupler of this invention, the location of the brackets should be kept in mind, so that the respective concrete anchors and bracket lie in a plane parallel to the longitudinal axis of the coupled pipes. The connecting element  24  is then passed through the crosspiece aperture and the one in the head of the concrete anchor and fastened in place. 
         [0056]    During use, if shifting of the pipes occurs, upon the application of a significant predetermined level of stress, failure has been designed in one or more ways. One way is for the rod  24  to fail by using a small enough diameter or making it of a material such as plastic which when subjected to a predetermined level of stress results in failure. Another way to engineer for failure is by making the thickness of the bracket crosspiece thin enough to break upon being subjected to a predetermined level of stress. Still another way for the device to be engineered for failure is by selecting the band to be of a strength that will snap when exposed to sufficiently high pressure caused by expansion of the coupler due to internal pressure within the plastic pipe causing shifting of the coupler over the corrugations of the plastic pipe. In each of these scenarios, while attempts are made to keep the coupler in place so as to provide a seal between the concrete pipe and the plastic one, by engineering failure with respect to the coupler, while the coupler may suffer damage, no damage occurs to the two pipes which can be rejoined. 
         [0057]    While the form of apparatus herein described constitutes a preferred embodiment of the present invention, it is to be understood that the invention is not limited to this precise form of apparatus and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.