Abstract:
A coupling is provided for corrugated conduits. The coupling is formed unitarily from a resin material and has first and second coupling halves that are joined unitarily along a living hinged. The halves can be rotated about the living hinge from an open position to a closed position. Ends of corrugated conduits can be engaged between the coupling halves when the coupling halves are in the closed position. Edges of the coupling halves opposite the hinge have locking structures for holding the halves in the closed position.

Description:
This application claims priority to an application entitled “COUPLING FOR CORRUGATED CABLE CONDUITS FOR ENCLOSING CABLES BRANCHED OR SPLICED FROM A TRUNK CABLE ASSEMBLY” filed in the United States Patent and Trademark Office on May 3, 2004 and assigned Ser. No. 60/567,901, the contents of which are hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a coupler for corrugated conduits. 
   2. Description of the Related Art 
   Many large residential, commercial and office buildings are provided with complex arrays of telecommunication cables. An array of parallel cables is likely to extend from a main junction box in a building and will traverse interior walls, ceilings and/or floors of the building to specified locations where the cables can be accessed. Small trunks of cables are likely to be branched or spliced from a main trunk of cables to direct the smaller trunk of cables towards a particular floor of a building or a particular area on a floor. Individual cables then may be branched or spliced from the small trunks of cables. 
   Cables often must be bent to accommodate required changes of direction. However, very abrupt bends of a cable can create stresses on the outer curvature of the bend. Such stresses can stretch and damage the insulation coating on the outside of a cable and can damage the shielding layers provided on many cables. Corrugated conduits protect cables and help to ensure smooth bends. Plastic corrugated conduits can be manufactured inexpensively and provide a very good strength-to-weight ratio. Additionally corrugated conduits exhibit sufficient flexibility to facilitate both storage, transportation and installation. Couplers are available for joining corrugated conduits in end-to-end relationship. Examples of such couplers are shown, for example, in U.S. Pat. Nos. 4,168,091, 4,273,367, 4,443,031, 4,647,074, 4,795,197, 5,015,013, 5,458,380, 6,145,896, 6,398,270 and 6,595,473. 
   Corrugated conduits are not well suited to the branching or splicing that often is required for telecommunication cables. As a result, installers often use hand tools, such as cutting pliers, snips or knives to make a hole in a corrugated conduit. The required number of telecommunication cables then are directed from the main trunk and through the hole. The hole formed in a corrugated tube in this manner typically provides a sharp edge that can damage the cable. Additionally, an installer is likely to bend the branched cable or cables sharply at the hole, thereby creating stresses and strains, particularly along the outer edge of the bend. The branched cables may be passed through another conduit. However, there often is a space between the conduit for the main trunk of cables and the conduit for the branched cables. Regions of the branched cables between the hole in the main conduit and the end of the branch conduit are exposed and may be subject to damage. Additionally, the process of cutting a hole in the side of a conduit is labor intensive, time consuming and creates the potential for damaging cables during the cutting process. 
   Connectors are available for more than two opposed corrugated tubes. For example, U.S. Pat. No. 5,046,766 shows a connector for two corrugated tubes disposed in axially aligned and end-to-end relationship and one corrugated tube that extends at a right angle to the aligned tubes. This connector, however, requires the cables to be bent at a sharp right angle through the connector. As explained above, a sharp right angle bend generally is not desired. U.S. Pat. No. 5,272,459 shows a Y-connector that permits two corrugated tubes to extend from the wall of a junction box or the like. The Y-shaped coupler has two separate halves that can be placed over one another and around the two corrugated tubes. A non-corrugated portion of the coupler then is passed through an aperture in the wall and is secured to the wall by a nut or similar fixturing device. 
   It is an object of the subject invention to provide a coupler that enables a corrugated tube to be branched efficiently from axially aligned corrugated tubes. 
   It is another object of the subject invention to provide a coupler that can be molded efficiently and that reduces the assembly of parts required at the installation site. 
   SUMMARY OF THE INVENTION 
   A coupling is provided for corrugated conduits. A coupling in accordance with the invention is formed from a resin material and includes opposed first and second coupling halves that are joined unitarily along a living hinge. The halves can be rotated about the living hinge from an open position to a closed position. Ends of corrugated conduits can be positioned on one of the coupling halves when the coupling halves are in the open position. Alternatively, the coupling halves can be engaged securely around the corrugated conduits when the coupling halves are rotated about the hinge into the second position. 
   Portions of the coupling opposite the living hinge include a locking structure with a ridge on the first half of the coupling and with a latch on the second half of the coupling. The ridge and the latch each may extend substantially the entire length of the coupling. The coupling may have a groove formed on one of the first and second halves of the coupling and a rib may be formed on the other of the first and second halves of the coupling at locations spaced inwardly from the living hinge. The groove and the rib are dimensioned, disposed and configured to nest with one another as the coupling is rotated into the closed condition. Interior portions of the first and second halves of the coupling are formed with grooves and ribs dimensioned to nest with the grooves and ribs defined by the corrugated conduit. 
   A continuous tubular section may be formed at one end of the coupling. The continuous tubular section may be formed unitarily with one half of the coupling, but preferably is not connected directly to the opposed half of the coupling. The continuous tubular section may include an array of external threads extending from the end of the coupling and a flange may be formed at the inward end of the array of threads. The external threads may be configured for threaded engagement with a nut. Thus, this embodiment can be employed for connecting a corrugated conduit to a junction box, a panel or the like. 
   The coupling may include a downstream main trunk coupling, an upstream main trunk coupling and a branch coupling. The upstream and downstream main trunk couplings preferably are aligned along a common axis. The branch coupling preferably is aligned to the axis of the upstream and downstream main trunk couplings at an acute angle, and preferably an angle of approximately 30°. 
   Sides of the downstream main trunk coupling diametrically opposite the living hinge are formed with interengageable latch structures for holding the first and second halves of the coupling in the closed condition. The latch structures preferably include a latching ridge that extends substantially continuously along the first half at a location diametrically opposite the living hinge and at least one locking claw that extends along the edge of the second half of the coupling opposite the hinge. The claw is configured to engage the ridge as the first and second halves of the coupling are rotated into the closed position. Thus, the claw will resiliently deflect out and over the ridge. However, the claw will return resiliently toward an undeflected condition to engage the ridge when the first and second halves of the coupling reach the closed position. 
   Sides of the branch coupling opposite the living hinge of the coupling also are formed with a ridge and latch similar to the above-described ridge and latch formed on the downstream main trunk coupling. The latch preferably is an elongate latch that extends along at least a major portion of the branch trunk coupling. The ridge preferably extends along a comparable distance. In a preferred embodiment, the ridge extends along the entire length of the branch coupling and further extends continuously onto the downstream branch coupling. 
   A locking structure also is provided on the upstream main trunk coupling at a location diametrically opposite the living hinge. The locking structure on the upstream main trunk coupling may be a ridge and latch similar to the above-described ridge and latch structures on the downstream main trunk coupling and on the branch coupling. 
   The side of the branch coupling diametrically opposite the locking structure thereof may include alignment members for aligning the edges of the branch coupling opposite the locking structure. The alignment structures may include ribs and grooves that interengage when the first and second halves of the coupling are rotated into the closed position. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a coupling in accordance with a first embodiment of the invention. 
       FIG. 2  is a top plan view of the coupling shown in  FIG. 1 . 
       FIG. 3  is an end elevational view of the coupling shown in  FIGS. 1 and 2 . 
       FIG. 4  is a cross-sectional view taken along line  4 - 4  in  FIG. 2 . 
       FIG. 5  is a cross-sectional view taken along line  5 - 5  in  FIG. 2 . 
       FIG. 6  is a perspective view of an alternate embodiment of the coupling. 
       FIG. 7  is a perspective view of a further embodiment of the invention. 
       FIG. 8  is a top plan view of the coupling shown in  FIG. 7 . 
       FIG. 9  is a cross-sectional view taken along line  9 - 9  in  FIG. 8 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A coupling in accordance with a first embodiment of the invention is identified generally by the numeral  10  in  FIGS. 1-5 . The coupling  10  is molded unitarily from a resin material and includes first and second semi-cylindrical halves  12  and  14  that are joined unitarily to one another by a living hinge  16 . Each half includes an inner semi-cylindrical surface characterized by an array of corrugations  18  configured to nest with grooves and ridges formed on the outer circumferential surface of the corrugated conduit with which the coupling  10  is to be connected. 
   The first semi-cylindrical half  12  of the coupling  10  includes a free edge  22  substantially diametrically opposite the hinge  16 . A locking ridge  24  is formed on the outer circumferential surface of the first cylindrical half  12  at a location spaced slightly from the free edge  22 . The locking ridge  24  projects out from the outer circumferential surface of the first semi-cylindrical half  12  and extends substantially completely along the length of the first semi-cylindrical half  12 . The locking ridge  24  defines a substantially right angle positioning step  26  along the longitudinal side of the locking ridge  24  closer to the free edge  22  and a substantially right angle locking step  28  on the side of the locking ridge  24  opposite the positioning step  26 . 
   The second half  14  includes a second positioning step  30  facing inwardly thereon at a location near the ends of the corrugations  18  furthest from the hinge  16 . The second positioning step  30  is dimensioned and disposed to nest with the first positioning step  26  defined by the locking ridge  24  on the first half  12 . This interengagement of the first and second positioning steps  26  and  30  substantially prevents the free edge  22  of the first half  12  from deflecting outwardly when the coupling  10  is in the closed position. 
   The second half  14  further includes an elongate latch  32  projecting substantially tangentially from the second positioning step  30 . The elongate latch  32  includes a deflectable panel  34  defining a substantially tangentially aligned plane and an inwardly projecting pawl  36 . The inwardly projecting pawl  36  includes a slanted deflection generating surface  38  at the free end of the latch  32  and a locking edge  40  that is aligned substantially perpendicularly to the plane of the panel  34 . 
   Portions of the first half  12  adjacent the hinge  16  include an outwardly facing notch  42  extending the entire length of the first half  12 . Portions of the second half  14  adjacent the hinge  16  include an inwardly facing notch  44  extending the entire length thereof. The notches  42  and  44  are dimensioned and configured to nest with one another when the first and second halves  12  and  14  are rotated into the closed position. 
   The coupling  10  may be used by positioning first and second corrugated tubes (not shown) in the first half  12  so that the corrugations of the tube nest with the corrugations  18  in the first half  12 . The second half  14  then is rotated about the hinge  16  and towards the closed position. The slanted surface  38  of the pawl  36  will engage the ridge  24 . This engagement will cause the panel  34  to deflect outwardly, thereby permitting the pawl  36  to ride over the ridge  24  as the coupling  10  is moved towards the closed position. Sufficient movement of the coupling  10  towards the closed position will permit the locking edge  40  of the pawl  36  to align with the locking edge  28  of the locking ridge  24 . As a result, the panel  34  will return resiliently towards an undeflected condition so that the locking edge  40  of the pawl  36  will snap into engagement with the locking step  28  of the locking ridge  24 . In this position, the elongate grooves  42  and  44  at locations on the first and second halves  12  and  14  adjacent the hinge  16  will nest with one another. Additionally, the positioning steps  22  and  30  will nest with one another to prevent an outward deflection of the first half  12  that could disengage the latch  32  from the locking ridge  24 . Hence, the coupling  10  is held securely in the closed position around the two corrugated tubes. 
     FIG. 6  shows a variation of the coupling  10  described above and illustrated in  FIGS. 1-5 . In particular,  FIG. 6  shows a coupling  50  with a first half  52  and a second half  54  that are joined unitarily to one another by a hinge  56 . First and second halves  52  and  54  are structurally and functionally very similar to the first and second halves  12  and  14  described above with respect to the first embodiment. However, the first half  52  further is formed with a continuous substantially cylindrical nipple  58  at one longitudinal end thereof. The nipple  58  has an array of external threads and a flange  59 . The coupling  50  is employed by positioning a single corrugated tube (not shown) in the first half  52  so that the corrugated tube extends away from the nipple  58 . The second half  54  then is rotated about the hinge  56  and is locked to the first half  52  substantially as described above with respect to the coupling  10  illustrated in  FIGS. 1-5 . The coupling  50  then can be used by inserting the threaded nipple  58  through an aperture, such as the aperture in a panel, wall or junction box. A nut (not shown) then can be threaded onto the threads of the nipple  58  so that the coupling  50  is held securely in position with the corrugated tube extending therefrom. 
   A coupling in accordance with a third embodiment of the invention is identified generally by the numeral  60  in  FIGS. 7-9 . The coupling  60  includes first and second halves  62  and  64  that are joined unitarily to one another by a hinge  66 . 
   The first half  62  includes a first upstream main trunk connector  68 , a first downstream main trunk connector  70  and a first branch connector  72 . The first upstream and downstream main trunk connectors  68  and  70  are aligned along a common axis. The first branch connector  72  is aligned along an axis that defines an angle of about 30° to the axis defined by the first upstream and downstream main trunk connectors  68  and  70 . Thus, the first half  62  effectively defines a Y-shape. Interior portions of the first half  62  near the first upstream and downstream main trunk connectors  68  and  70  and the first branch trunk connector  72  are formed with arrays of corrugations configured and dimensioned to nest with corrugations on the corrugated tubes that are to be coupled. Outer surface regions of the first half along sides opposite the hinge  66  include locking ridges structurally and functionally comparable to the locking ridge  24  on the coupling  10  of the first embodiment. More particularly, the first downstream main trunk connector  68  includes a first downstream locking ridge  74  diametrically opposite the hinge  66 . The first upstream main trunk connector  70  includes a locking ridge  76  diametrically opposite the hinge  66 . Additionally, the first branch connector  72  includes a locking ridge  78  that extends substantially continuously from the locking ridge  74  along the entire length of the first branch connector  72 . 
   Positioning steps are defined substantially adjacent the locking ridges  74 - 78  and have configurations and functions similar to the positioning step  22  on the first half  12  of the coupling  10  described above and illustrated in  FIGS. 1-5 . Additionally, portions of the first half  62  substantially adjacent the hinge  66  include a positioning groove substantially identical to the positioning groove on the coupling  10 . 
   The second half  64  of the coupling  60  is in many respects a mirror image of the first half  62 . In particular, the second half  64  includes a second upstream main trunk connector  88 , a second downstream main trunk connector  90  and a second branch connector  92 . Additionally, the second half  64  includes latches  94 ,  96  and  98  that will releasably engage the locking ridges  74 ,  76  and  78  respectively. The latches  94 ,  96  and  98  are structurally and functionally similar to the latch  30  described and illustrated with respect to the first embodiment. Additionally, the second half  64  includes a positioning step inwardly from the respective latches  94 - 98  that will engage the corresponding positioning step on the first half in a manner substantially as described with respect to the first embodiment. 
   The coupling  60  is employed by positioning a first conduit (not shown) in the first upstream main trunk connector  68  so that the corrugations of the conduit nest with the corrugations in the first half. Wires or cables are directed through the conduit in a conventional manner. At least one of the cables is branched from the main trunk, while other of the cables continue in a substantially linear manner. A main trunk of cables is threaded through a second conduit, and an end of the second conduit is positioned in the first downstream connector  70  so that the corrugations of the downstream conduit nest with the corrugations in the first downstream main trunk connector  70 . The branch cables then are directed through a branch conduit, and an end of the branch conduit is placed in the first branch connector  72 . The branch conduit, therefore, is positioned in an alignment to avoid a sharp bend in any of the cables or wires that could create stresses or strains. The second half  64  then is rotated about the hinge  66  and towards a closed position. This rotation of the second half  64  will cause the latches  94 - 98  to engage and releasably lock with the locking ridges  74 - 78 . Additionally, the positioning steps will nest with one another to prevent any significant outward deflection of free edges of the first or second halves  62  or  64  that could permit the coupling  60  to open.