Abstract:
A connector sleeve for joining conduit, and a joint construction, and a coupling assembly for joining conduit; and a method for joining conduit using a coupling assembly.

Description:
[0001]    This application is a divisional of application Ser. No. 12/325,336, filed Dec. 1, 2008, which is a divisional of application Ser. No. 11/147,123, filed Jun. 7, 2005. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present disclosure relates to a joint construction for conduit, a coupling assembly for joining conduit, a connector sleeve for joining conduit, and to a method for joining conduit using a coupling assembly. It finds particular application in conjunction with electrical metallic tubing and will be described herein primarily by way of reference thereto; however, it will be appreciated that the invention finds utility in conjunction with all manner of conduits, including pipes, tubes, ducts, and the like. 
       BACKGROUND OF THE INVENTION 
       [0003]    Electrical metallic tubing (EMT) is thin-wailed tubing used to contain is and protect electrical wires. EMT is commonly used in warehouses, gymnasiums, factories, and the like. Such conduit is traditionally manufactured in ten (10) foot lengths. The conduit sections can be connected end-to-end for use in applications requiring longer sections. Conduit connectors and conduit coupling assemblies are well known in the art. Many coupling designs require the use of a connection sleeve to hold the lengths of conduit together. These connectors are manufactured and shipped independently of the conduit and may require additional parts to assemble. Maintaining inventory of and installing the individual connector parts takes time and costs money. It would therefore be desirable to have a connector sleeve for use in joining conduit, a coupling assembly for joining conduit, and a method for joining conduit using a coupling assembly. The present invention provides connector sleeves, coupling assemblies, and methods which overcome the above-referenced problems and others. 
       SUMMARY OF THE INVENTION 
       [0004]    In one aspect, a joint construction for conduit includes first and second sections of conduit having coaxially overlapping end areas, wherein the first section end area has an enlarged diameter relative to the second section end area. A coupling member is affixed to the first section end area and includes a first and second end portions. The first end portion is dimensioned to be coaxially received within the first section end area and the second end portion has external threads and axially extends from the first end portion. The coupling member includes an axial bore dimensioned to coaxially receive the second section end area. An annular gland nut includes internal threads rotatably engaging the external threads of the second end portion to selectively axially advance and retract the gland nut when the gland nut is respectively rotated in opposite directions. A compression washer circumscribes the second section and is interposed between the coupling member second end portion and the annular gland nut and is urged into engagement with the second section end portion to resist axial movement of the second section relative to the first section. 
         [0005]    In another aspect, a coupling assembly for joining conduit includes a conduit having at least one swaged or enlarged diameter end, a connector sleeve, a compression washer, and an internally threaded annular gland nut. The end of a first conduit is swaged to form a bell portion. The bell portion is sized to receive a connector sleeve. The connector sleeve has an insertion end sized to fit within the bell portion of the first conduit, and an externally threaded second end sized to receive a second conduit. The insertion end of the connector sleeve is coupled within the bell portion of the first conduit. The internally threaded annular gland nut, sized to receive the threaded end of said connector sleeve and encircling a compression washer, is engaged onto the threaded end of the connector sleeve, thus completing the coupling assembly. 
         [0006]    In yet another aspect, a connector sleeve for joining conduit includes an annular sleeve having a first end and a second end. The first end, or insertion end, has an outer diameter sized to be received by a first conduit. The second end, or receiving end, is externally threaded and has an inner diameter sized to receive a second conduit. 
         [0007]    In still another aspect, a method for joining conduit using a connector assembly is provided. The end of a first conduit is swaged to receive a connector sleeve. The connector sleeve has an insertion end and an externally threaded second end. The connector sleeve is then coupled within the swaged end of the first conduit. A compression washer is encircled by an internally threaded annular gland nut. The compression washer and the gland nut are Wed over a second conduit. The end of the second conduit is then inserted into the connector sleeve. The gland nut, with washer, is then engaged onto the threaded end of the connector sleeve, thereby tightening the compression washer about the end of the second conduit. 
         [0008]    One advantage of the conduit coupling assembly described herein resides in its ability to securely connect two lengths of conduit coaxially. 
         [0009]    Another advantage of the embodiments of the invention described herein is found in that it offers a conduit joint which may resist twisting and/or separation of the coupled conduit sections. A further advantage of the coupling assembly described herein is found in that it may be provided as an integral part of the conduit. For example, the coupling assembly components may be preattached to the conduit sections prior to shipping the conduit sections to the job site, e.g., during manufacture, at a centralized location, etc. In this manner, manufacturing costs, installation time, and/or inventory concerns associated with maintaining separate inventories of conduit sections and couplers may be reduced. 
         [0010]    Yet another advantage of the coupling assembly embodiments herein is the ease of which a connection between conduit sections may be assembled and disassembled. 
         [0011]    Still further advantages and benefits of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings, wherein like reference numerals are used for like or analogous components throughout the several views, are only for purposes of illustrating preferred embodiments and are not to be construed as limiting the invention. 
           [0013]      FIG. 1  is an exploded side view illustrating a coupling assembly according to a first embodiment of the present invention. 
           [0014]      FIG. 2  is an exploded top plan view of the conduit and connector sleeve shown in  FIG. 1 . 
           [0015]      FIG. 3  is a side-sectional view of a pipe joint construction according to a second embodiment of the present invention. 
           [0016]      FIG. 4  is an exploded side view of the conduit and connector sleeve portions of the coupling assembly depicted  FIG. 3 . 
           [0017]      FIG. 5  is a side exploded view illustrating a coupling assembly according to a further embodiment. 
           [0018]      FIG. 6  is a side view of a coupling assembly according to yet another embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    With reference to the drawing figures, there appears a conduit joint construction  10  ( FIG. 1 ) according to a first embodiment and a conduit joint construction  11  ( FIG. 3 ) for connecting two conduit sections  12 ,  14  in coaxial, end-to-end fashion. The conduit  12  has at least one receiving end  18 . The receiving end  18  is defined by a swaged or bell portion  20 . The bell portion  20  has an enlarged diameter with respect to the conduit  34  is designed to receive a connector sleeve  22 . The conduit is preferably electrical metallic tubing and may be formed of steel, aluminum or aluminum alloy, or other metal or metal alloy. Other conduit materials are also contemplated, such as PCV and other plastics. 
         [0020]    The connector sleeve  22  has an externally threaded end  24  and an insertion end  26 . Furthermore, the connector sleeve  22  defines an axial channel or bore having an internal diameter sized to receive an end of the second conduit  14 . The insertion end  26  of the connector sleeve  22  can be coupled within the receiving end  18  of conduit  12  via any of a number of methods. For example, the coupling or fastening between the insertion end  26  of the connector sleeve  22  and the receiving end  18  of the conduit  12  can be achieved by a friction fit between the exterior-facing surface of the insertion end  26  and the interior-facing surface of the bell end  18 , by a mechanical fastener such as one or more rivets, screws or other threaded fasteners, clips, clamps, or the like, a welded joint, an adhesive bond such as epoxy or other adhesive, roll grooving for conduit formed of PVC or other plastic, the connector sleeve may be secured to the bell end via a glue or adhesive bond, or alternatively, may be integrally formed or molded. 
         [0021]    In the embodiment appearing in  FIGS. 3 and 4 , the coupling member  22  is secured within the bell portion via outwardly dimpling or otherwise deforming the connector sleeve and bell portion  20  whereby one or more  20  protrusions are formed on the exterior-facing surface of the connector sleeve  22  which engage and are complimentary with a corresponding number of depressions formed in the inward-facing surface of the bell portion  20 . However, inwardly dimpling or otherwise deforming the connector sleeve and bell portion  20  is also contemplated whereby one or more protrusions are formed on the interior-facing surface of the connector sleeve  22  which engage and are complimentary with a corresponding number of depressions formed in the outward-facing surface of the bell portion  20 . In still further embodiments, the insertion end of the sleeve within may be rotatably coupled to the receiving end of the first conduit via external threads formed on the exterior facing surface of the insertion end  26  and complimentary mating internal threads formed on the interior facing surface of the bell portion  20 . 
         [0022]    With specific reference now to the embodiment shown in  FIGS. 1 and 2 , there is illustrated one method for securing the connector sleeve  22  within the receiving end  18 . The bell portion  20  includes one or more (two in the depicted embodiment) dimples or protrusions  40  formed thereon. Each dimple  40  includes an opening  42  extending therethrough. A tubular rivet  44  having a threaded interior is then clinched on the top of each of the dimples  40  and through the holes  42 . For each hole  42 , there is a corresponding aligned hole  48  formed in the connector sleeve  22 . A threaded fastener  46  is rotatably secured to each of the threaded rivets  44  and extends into the holes  48 . Preferably, each of the holes  48  is tapped for form internal threads which likewise rotatably engage the threaded fastener  46 . 
         [0023]    It will be recognized that the depicted embodiment employing axially spaced apart fasteners is exemplary only and that other positions and configurations of fasteners may be provided. For example, in certain embodiments, only a single fastener may be provided. In other embodiments, two or more axially aligned fasteners, e.g., circumferentially spaced about the longitudinal axis of the connector sleeve  22  and bell portion  20 , may be provided. 
         [0024]    In certain embodiments, each threaded fastener  46  is preferably of a length such that the threaded end thereof will engage the opening  48  without extending into the interior portion of the connector sleeve  22 , so as to avoid interfering with the received end of the conduit  14 . In certain other embodiments, the threaded fasteners  46  are of a length which will extend into the interior of the connector sleeve  22 . In such embodiments, the one or more fasteners may be positioned so as to avoid interfering with the received end of the conduit  14 , e.g., behind an internal stop, or alternatively, the threaded end of one or more of the fasteners  46  may extend radially inwardly so as to define an internal stop, as described hereinbelow. 
         [0025]    With specific reference now to  FIGS. 3 and 4 , there is shown an alternative means for coupling the connector sleeve  26  to the bell portion  20  wherein the connector sleeve  22  and the bell portion  20  are simultaneously outwardly deformed, e.g., via dimpling. By outwardly pressing the sleeve  22  and bell portion  20 , one or more protrusions  32  are formed on the exterior-facing surface of the connector sleeve  22  which engage and are complimentary with a corresponding number of depressions  34  formed in the inward-facing surface of the bell portion  20 . 
         [0026]    It will be recognized that the depicted embodiment employing axially aligned, and radially spaced apart deformations is exemplary only and that other positions and configurations of the deformations may be provided. For example, in certain embodiments, only a single deformed region may be provided. In preferred embodiments, two or more axially aligned deformation, e.g., two, three, four, five, six, seven, eight, or more deformations circumferentially spaced about the longitudinal axis of the connector sleeve  22  and bell portion  20 , may be provided. 
         [0027]    Advantageously, where a plurality of radially spaced deformations are provided, preferably, e.g., from four to eight although other numbers are contemplated, the dimples or other deformations are formed in such a way so as to provide surface features, preferably protrusions, on the enlarged end area  18  so as to facilitate engagement by a gripping tool such as a wrench, pliers, or the like. In this manner, during installation, the tool may be used to engage the end area  18  to provide additional leverage and/or prevent rotation of the conduit  12  and the connector sleeve  22  relative to the gland nut  30  when the gland nut is rotated during assembly and disassembly of the pipe joint construction. 
         [0028]    It will be recognized that by outwardly deforming the connector sleeve  22  and bell portion  20 , interference with the inserted end of the conduit  14  during assembly, as well as interference with wiring or cabling to be drawn through the conduit, may be avoided. In certain other embodiments, however, the deformed regions may be dimpled or otherwise deformed inwardly. In such embodiments, the one or more deformed regions may be positioned so as to avoid interfering with the received end of the conduit  14 , e-g., behind an internal stop, or alternatively, may be positioned so as to define an internal stop, as described hereinbelow. Such inward deformations are also preferably of a radial extent which does not interfere with wiring or cabling to be passed through the conduit. 
         [0029]    With reference now to  FIGS. 1 and 2  and continued reference to  FIG. 3 , a compression washer or gland  28  is sized to fit about the conduit  14  and to be coaxially received within an internally threaded annular gland nut  30 . The compression washer may be formed of a metal or metal alloy, and preferably is formed of spring steel, or the like. The gland nut  30  is sized to rotatably receive the threaded end  24  of the connector sleeve  22 . The washer  28  is compressed around the second conduit  14  as the gland nut  30  is rotatably tightened about the threaded end  24  of the connector sleeve  22 . In an alternative embodiment, particularly wherein a PCV or other plastic conduit material is used, the compression washer may be replaced with an annular ring secured to the conduit  14 , e-g., via an adhesive or glue bond, or other fastener. 
         [0030]    The connector sleeve may optionally include an external stop for limiting the axial extent to which the connector sleeve  22  may be inserted into the bell portion  20 . The external stop may be any protrusion formed on or attached to the connector sleeve  22  and positioned between the insertion end  26  and the threaded end  24  of the connector sleeve  22  to allow insertion of the connector sleeve  22  into the bell portion  20  to some maximum or predetermined depth. In the embodiments depicted in  FIGS. 1-3 , the shoulder  50  of the enlarged diameter threaded end  24  serves as an external stop, although other external stop member configurations such as one or more ridges or other protrusions, such as an annular ridge or a segmented series ridges, and the like, are also contemplated. Optionally, the external stop member can include a peripheral shape and/or one or more peripheral surface features adapted to be engaged by a wrench or other gripping tool. 
         [0031]    The connector sleeve  22  may optionally include an internal stop for limiting the axial extent to which the conduit  14  may be inserted into the connector sleeve  22 . The internal stop may be any protrusion extending into the axial bore defined by the connector sleeve  22  positioned therein to allow insertion of the conduit  14  into the bell portion  20  to a predetermined depth and prevent the inserted end of the conduit  14  from passing completely through the sleeve  22 . Preferably, such an internal stop member should extend inwardly a sufficient distance to engage the edge of conduit end  14 , but without interfering with cabling or wiring to be passed through the conduit. In the embodiment depicted in  FIG. 3 , the radially inwardly extending flange or lip  52  of the connector sleeve  22  serves as an internal stop member, although other internal stop member configurations are contemplated, including without limitation one or more fasteners ends additionally securing the connector sleeve  26  within the bell portion  20  as described above, or, one or more radially inwardly formed dimples or deformations for securing the connector sleeve  26  within the bell portion  20  as described above. 
         [0032]    In still further embodiments, the connector sleeve  22  can have modified internal and/or external surface features so as to prevent relative rotation between the connector sleeve  22  and the bell portion  20  and/or relative rotation of the second conduit  14  within the sleeve  22 . For example, the internal and/or external surfaces of the washer  28  may be crosshatched to increase the friction. Alternatively, the connector sleeve  22  may be keyed or otherwise provided with a complimentary cross-sectional shape relative to the bell portion and/or the inserted end of the conduit  14 . 
         [0033]    In certain embodiments, the compression washer  28  may have a beveled or tapered leading edge such that the washer  28  is wedged between the connector sleeve  22  and the second conduit  14  as the gland nut  30  is tightened via rotation of the nut  30  with respect to the threaded end  24 . The inner and/or outer surfaces of the compression washer  28  may be modified to increase the friction between the compression washer  28  and the second conduit  14  and/or between the compression washer  28  and or the connector sleeve  22 . For example, the internal and/or external surfaces of the washer  28  may be crosshatched to increase the friction. 
         [0034]    Referring now to  FIG. 5 , there appears a conduit section  12  having an enlarged end  18  for receiving a connector sleeve  22 . The connector sleeve  22  includes a threaded end  24 , an insertion end  26 , and a raised shoulder  50 . It will be recognized that the coupling assembly depicted in  FIG. 5  may include any of the fastening or coupling means for securing the sleeve  22  within the bell end  18  of the conduit  12  and described above. 
         [0035]    An optional annular gasket or sealing ring  54  is supported on the sleeve insertion end  26 . The material forming the sealing ring or gasket  54  may be, for example, a metal or metal alloy, such as steel, aluminum, zinc alloy, etc., or a synthetic or natural plastic, rubber, or elastomeric material. Optionally, the gasket  54  may be seated in an annular groove or channel (not shown) formed on the connector sleeve insertion end  22  adjacent the shoulder  50 . The sealing ring or gasket  54  fills any gap between the shoulder  50  and the end of the bell portion  18 , thereby preventing or reducing the infiltration of moisture, dirt, debris, smoke, and other environmental factors into or out of the conduit. 
         [0036]    Referring now to  FIG. 6 , there appears a pipe joint assembly  111  including a conduit section  112  having an end  148  coaxially received within an insertion end  126  of an external sleeve  122 , The sleeve  122  includes a threaded end  124  having an internal diameter sized to receive an end of a conduit section  14  to be joined to the conduit section  112 . An internal stop member (not shown) for the received ends of the conduit sections  112  and  14 , such as a radially inwardly protruding member or flange may be provided within the sleeve  122  intermediate the insertion end  126  and the threaded end  124  of the sleeve  122 . An annular sealing ring or gasket (not shown) may optionally be provided to seal any gap between the outer surface of the insertion end  118  of conduit  114  and an inner surface of the sleeve  122 . 
         [0037]    A compression washer or gland  28  is sized to fit about the conduit  14  and to be coaxially received within an internally threaded annular gland nut  30 . The gland nut  30  is sized to rotatably receive the threaded end  124  of the connector sleeve  122 . The washer  28  is compressed around the second conduit  14  as the gland nut  34 ) is rotatably tightened about the threaded end  24  of the connector sleeve  22 . The washer  28  may include a beveled or tapered leading edge to wedge the washer between the threaded end  124  of the sleeve  422  and the conduit section  14 . In alternative embodiments, the compression washer  28  may be replaced with an annular ring secured to the conduit  14 , e.g., via an adhesive or glue bond, or other fastener. 
         [0038]    In the depicted exemplary embodiment, the connector sleeve  122  is secured to the conduit section  112  via a plurality of outward dimples or deformations  134 . However, it will be recognized that any of the coupling methods shown and described above by way of reference to  FIGS. 1-4  for securing the connector sleeve  22  to conduit section end  18  may likewise be adapted for securing the connector sleeve  122  to the conduit section end  118 . 
         [0039]    The invention has been described with reference to the preferred embodiments. Modifications and alterations will occur to others upon a reading and understanding of the preceding disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.