Abstract:
A coupler for coupling adjacent end portions of corrugated plastic pipe includes first and second arcuate members that cooperate with each other to surround and interfit with the corrugations of the plastic pipe. A stop member on one of the members enables the other member to be properly positioned over the other member when forming the coupler. Circumferentially aligned and spaced-apart attachment members resist relative movement of the two coupling members when backfilling the coupler and the pipes coupled by the coupler.

Description:
FIELD OF THE DISCLOSURE 
     The disclosure relates to large-diameter plastic corrugated pipe, and in particular, to a pipe coupler for coupling adjacent end portions of large-diameter plastic corrugated pipe. 
     BACKGROUND OF THE DISCLOSURE 
     Large-diameter plastic corrugated pipe used in routing stormwater runoff is typically 24 inches to 60 inches in diameter. The pipe is extruded with annular, circular corrugations and valleys having a standardized geometry, the corrugations spaced at a constant pitch along the length of the pipe. 
     Adjoining end portions of adjacent lengths of pipe are conventionally coupled together using either “clam-shell” type couplers or “two-piece” couplers. The coupler is wrapped around the end portions of the two pipes, fits in the outer corrugations of the two pipes, and is then tightened to couple the ends of the pipe together. Backfill is applied to cover the coupler and joint and complete the installation. 
     Clam-shell couplers, however, are expensive, available in limited sizes and widths, and can be difficult to handle and install in the field. 
     Two-piece couplers, on the other hand, can be difficult to install and are available in limited sizes and widths. Two-piece couplers have coupler pieces that must overlap to align connecting member or holes. Such alignment is difficult in the field. 
     Thus there is a need for an improved pipe coupler for coupling the pipe ends of large diameter plastic corrugated pipe that is relatively inexpensive, can accommodate a variety of sizes and widths of pipe, and is relatively easy to install in the field. 
     SUMMARY OF THE DISCLOSURE 
     Disclosed is an improved two-piece coupler for coupling the pipe ends of large-diameter plastic corrugated pipe. The improved two-piece coupler is inexpensive to manufacture, can be easily made for many different sizes and widths of pipe, and is relatively quick and easy to install in the field. 
     Embodiments of the disclosed coupler can be used to couple adjacent end portions of cylindrical members such as pipes in which each cylindrical member has a corrugated outer surface with circular corrugations and valleys. 
     The coupler includes a first coupling member and a second coupling member, the first and second coupling members separate members not otherwise attached to one another. 
     Each of the first and second coupling members include an arcuate body extending along an axis, the axis defining a circumferential direction around the axis, the body having a a first end and a second end circumferentially spaced from the first end, with a gap between the ends. A number of circular corrugations and valleys extend around the axis of the body from the first end to the second end. 
     The second coupling member is configured to be placed over the gap of the first coupling member and overlap the first and second ends of the first coupling member and interfit with the corrugations and valleys of the first coupling member and the corrugations and valleys of the end portions of the cylindrical members received in the first coupling member and thereby cooperate with the first coupling member in completely surrounding the end portions of the cylindrical members. 
     The inner surfaces of the first and second coupling members are preferably radially sized to form an interference fit with the outer surfaces of the cylindrical members to assure a tight fit between the coupling members and the cylindrical members. In other possible embodiments the coupling members can be sized to not form an interference fit with the cylindrical members. 
     In possible embodiments the first coupling member includes a stop member on an outer surface of the body of the first coupling member. The stop member enables the second coupling member to be properly positioned over the first coupling member and overlap the gap of the first coupling member. The second coupling member may include a handle that enables a user to interfit the second coupling member with the first coupling member while the second coupling member is supported against the stop member. 
     Preferably, a first connection member is on the outside of the body of the first coupling member, and a second connection member is on the body of the first coupling member or on the outside of the body of the second coupling member. When the two coupling members are interfitted together to couple the end portions of the cylindrical members, the connection members are circumferentially spaced from one another but are axially aligned with one another to enable a cable tie, bolt, or other connecter member to connect the two connection members and resist relative motion of the attachment members away from each other during backfill of the trench containing the coupler and coupled end portions. 
     The bodies of the first and second coupling members can be each formed from extruded plastic. The same or similar extruder can be used that extrudes corrugated plastic pipe to be coupled b the coupler. 
     Other objects and features will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing sheets illustrating one or more illustrative embodiments. 
    
    
     
       BRIEF SUMMARY OF THE DRAWINGS 
         FIG. 1  is a front view of a two-piece split pipe coupler, the two pieces being separated; 
         FIG. 2  is a right-side view taken along line  2 , 4  of  FIG. 1  of the larger coupler half; 
         FIG. 3  is a left-side view taken along line  3 ,  5  of  FIG. 1  of the larger coupler half; 
         FIG. 4  is a right-side view taken along line  2 , 4  of  FIG. 1  of the smaller coupler half; 
         FIG. 5  is a left-side view taken along line  3 , 5  of  FIG. 1  of the smaller coupler half; 
         FIGS. 6-8  illustrate the steps in installing the pipe coupler to join the adjacent pipe ends of two large-diameter plastic corrugated pipes; and 
         FIG. 9  is a front view of an assembled second embodiment pipe coupler. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-5  illustrate a two-piece pipe coupler  10 . The illustrated pipe coupler  10  is designed to receive within it and couple the adjacent pipe ends of plastic corrugated pipe having a standardized configuration of annular, circular corrugations and valleys spaced at a constant pitch along the length of the pipe. 
     The two-piece pipe coupler  10  includes a first, larger coupling member or coupler half  12  and a second, smaller coupling member or coupler half  14 . The two coupler halves  12 ,  14  surround and couple the pipe ends as will be described in more detail below. 
     The first coupler half  12  is a generally cylindrical member having a cylindrical body  16  that extends along and is axially symmetric about an axis  18  (the axis  18  is perpendicular to the drawing sheet in  FIG. 1 ). The cylindrical body  16  is fabricated from extruded plastic, such as extruded HDPE (high density polyethylene) or other moldable plastic. The body  16  is an arcuate member extending substantially more than 180 degrees about the axis  18  from a first circumferential end  20  to the opposite second circumferential end  22 . The illustrated body  16  extends about 200 degrees between the ends  20 ,  22  about the axis  18 . The body  16  has four annular, circular crowns or corrugations  24 , a set of annular, circular grooves or valleys  26  between the corrugations  24 , and annular, circular half valleys  28  on adjacent sides of the body  16 . In other possible embodiments the half valleys  28  are eliminated. 
     The corrugations  24  and the valleys  26 ,  28  are shaped to conform with and interfit with the corrugations and valleys of the pipes being coupled together. The inner radial dimensions of the corrugations  24  and the valleys  26 ,  28  are sized to be slightly smaller than the outer radial dimensions of the corresponding corrugations and valleys of the plastic pipe to be coupled by the coupler  10 . The outer radial dimensions of the corrugations  24  and the valleys  26 ,  28  of the coupler body  16  are sized to provide sufficient mechanical strength for coupling the pipes while still providing sufficient flexibility of the coupler body  16  to enable elastic deformation of the body  16  increasing the gap between the body ends  20 ,  22  when receiving the pipe ends into the body  16 . 
     The coupler half  12  further includes a sets of lugs that assist in assembling the coupler  10  and keeping the assembled coupler  10  together as will be discussed in greater detail below. The coupler half  12  includes a stop lug  30  and a pair of connection lugs  32 ,  34  adjacent the body end  20  and a pair of connection lugs  36 ,  38  adjacent the body end  22 . Each lug  30 - 38  is formed from a rectangular plastic plate that is welded to the body  16  and extends across the valley defined between a respective pair of corrugations. 
     The stop lug  30  extends across the center valley  26  between the center two corrugations  24  and is spaced a predetermined distance from the body end  20 . The stop lug  30  acts as a stop or stop member that helps locate the second coupler half  14  on the first coupler half  12 . The connector lugs  32 ,  34  are located on opposite sides of the stop lug  30  and are spaced further from the body end  20  than is the stop lug  30 . 
     The connector lugs  36 ,  38  are axially aligned with the lugs  34 ,  32  respectively and are adjacent to and spaced from the body end  20  the same distance the lugs  32 ,  34  are spaced from the body end  22 . 
     The coupler half  14  is a generally cylindrical member having a cylindrical body  40  that extends along and is axially symmetric about an axis  42  (the axis  42  perpendicular to the drawing sheet in  FIG. 1 ). The body  40  is otherwise identical to the body  16  except that the body  40  has a lesser arcuate length between ends than does the body  16 . The illustrated body  40  extends about 180 degrees about the axis  42  between a first body end  44  and a circumferentially opposite second body end  46 . The body  40  is able to span the gap between the ends  22 ,  24  of the body  16  with some overlap of the end portions of the body  16  when the coupler  10  is assembled. 
     The body  40  has four annular, circular crowns or corrugations  46 , a set of annular, circular grooves or valleys  48  between the corrugations  46 , and annular, circular half valleys  50  on adjacent sides of the body  40 . In other embodiments of the invention the half valleys  50  are eliminated. 
     In yet other possible embodiments, the second coupler half could have more corrugations and valleys than does the first coupler half. 
     The coupler half  14  further includes a handle  52  and a set of connector lugs  53 ,  54 ,  55 ,  56  that assist in assembling the coupler  10  and keeping the assembled coupler  10  together as will be discussed in greater detail below. 
     The handle  52  is adjacent to and relatively closely spaced from the body end  44 . The handle  52  is formed from a rectangular plate welded to the body  40 . The handle  52  is welded to the tops of the corrugations  46  and extends essentially the full width of the body  40 . 
     Each lug  53 - 56  is formed from a rectangular plastic plate that is welded to the body  16  and extends across the valley defined between a respective pair of corrugations. The connection lugs  53 ,  54  are adjacent to and spaced a predetermined distance from the body end  44  and between the body end  44  and the handle  52 . The connection lugs  55 ,  56  are adjacent to and spaced a predetermined distance from the body end  46 . The connection lugs  53 ,  54 ,  55 ,  56  are axially aligned with respective connection lugs  36 ,  38 ,  40 ,  42  When the coupler  10  is assembled as will be described in greater detail below. 
       FIGS. 6-8  illustrate the steps in installing the pipe coupler  10  to join the immediately adjacent pipe ends of two large-diameter plastic corrugated pipes  57 ,  58 . 
     The larger coupler half  12  is placed into a trench (not shown) that will receive the pipes  57 ,  58 , with the gap defined between the half ends  20 ,  22  facing up. The two pieces of pipe  57 ,  58  are then placed into the trench, with the immediately adjacent end portions of the pipes  57 ,  58  received into the coupler half  12 . See  FIG. 6 . The body  16  elastically deforms to receive the end portions of the pipes  57 ,  58  through the gap and into the first coupler half  12 . Two corrugations of each of the pipes  57 ,  58  are closely received into two corresponding corrugations  24  of the coupler half  12 . The coupler half  12  forms an interference fit with the pipes  57 ,  58  assuring a tight fit between the coupler half  12  and the pipes  57 ,  58 . 
     The smaller coupler half  14  is placed on top of the pipes  57 ,  58  and is aligned longitudinally with the lower coupler half  12 . See  FIG. 7 . The end  46  of the lower coupler half  14  is placed against the stop  30  of the lower coupler half  12 , thereby assuring that the coupler  10  will be assembled with the coupler half  14  substantially centered over the gap in the coupler half  12 . 
     A cable tie (not shown) is placed around and between the lug  32  of the larger coupler half  12  and the lug  55  of the smaller coupler half  14 , and another cable tie (not shown) is placed around and between the lug  34  of the larger coupler half  12  and the lug  56  of the smaller coupler half  14 . The cable ties can be loosely tightened to temporarily hold smaller coupler half  14  in alignment with the larger coupler half  12  during assembly. 
     The handle  52  of the coupler half  14  is then pulled down towards the end  22  of the coupler half  12 , until the upper portions of the corrugations of the pipes  57 ,  58  and the corrugations of the overlapping portions of the coupler half  12  are closely received in the corresponding corrugations of the coupler half  14 . See  FIG. 8  which illustrates the smaller coupler half  14  in a coupling position with respect to the larger coupler half  12 . The smaller coupler half  14  forms an interference fit with the pipes  57 ,  58  and the overlapping portions of the larger coupler half  12 , assuring a tight fit between the various components. 
     Additional cable ties (not shown) are then attached to and extend along the portions of the respective valleys extending between the axially aligned pairs of connector lugs  36 ,  38  and connector lugs  53 ,  54 . All the cable ties are then cinched tight to assure that the coupler halves  12 ,  14  will remain in place as intended while the trench containing the coupler  10  and pipes  57 ,  58  is backfilled to complete installation. 
     If desired, additional connection lugs can be located on the larger coupler halves. The handle  52  can also be used as a connection member or connection lug. 
     The illustrated coupler halves  12 ,  14  are manufactured by extrusion using the same or identical extruder used in manufacturing the pipes  57 ,  58 . The extruder extrudes lengths of pipe that are each otherwise identical to the standard pipe  57 ,  58  except that the inner radial dimensions of the extruded pipe are slightly larger than the standard pipe. The pipe is then cut in half lengthwise to form two 180-degree semicircular pipe lengths. The semicircular pipe lengths are cut to axial lengths with the desired number of corrugations for the coupler, thereby forming the bodies  40  of the smaller coupler halves  14 . 
     The illustrated coupler  10  engages and interfits with two corrugations of each pipe  57 ,  58 ; other coupler embodiments could interfit with a fewer or greater number of corrugations. One coupler half could interfit with a different number of corrugations than the other coupler half. 
     Other semicircular pipe lengths are cut into multiple arc-shaped lengths of pipe, and these lengths are then cut to the desired axial lengths to form arcuate “ears” that are attached to the smaller coupler halves to form the larger coupler halves. For example,  FIG. 1  shows that the larger coupler half  12  is fabricated by welding an ear  50  to a body  40 . 
     In yet other possible embodiments, bolted connections between coupler halves replace the cable tie connections.  FIG. 9  illustrates an assembled coupler  110  similar to the coupler  10  and having a smaller coupler half  111  and a larger coupler half  112  (for clarity, the pipes are omitted). The coupler half  112  includes connector lugs  114 ,  115 ,  118 ,  119  similar to the lugs on the coupler half  14 . The coupler half  111  includes connector lugs  116 ,  117 ,  120 ,  121  similar to the lugs on the coupler half  12 . Each of the lugs  114 - 121  is formed with a radially open-ended slot that enables a bolt  125 ,  126 ,  127 ,  128  or other clip or fastener to extend between pairs of lugs and mechanically connect the lugs on the coupler half  111  with the lugs on the coupler half  112 . Close alignment of the lugs is not required, simplifying assembly. In other embodiments the lugs may include through holes rather than slots, the holes large enough to accept some misalignment while still permitting a bolt or fastener to pass through the holes for mechanically connecting the coupler halves together. 
     The illustrated coupler  10  is shown coupling the adjacent ends of large-diameter corrugated plastic pipe. The disclosed coupler is not limited to joining pipe ends; it can be used to join an end of a tee or elbow pipe coupling or the like. The disclosed coupler is not limited to use only with pipe; the coupler can join solid cylindrical members having the same outer profile of corrugations and valleys. The disclosed coupler can also be used to couple adjacent ends of members having a diameter less than 24 inches or greater than 60 inches. 
     While one or more embodiments have been described in detail, it is understood that this is capable of modification and that the disclosure is not limited to the precise details set forth but includes such changes and alterations as fall within the purview of the following claims.