Patent Publication Number: US-11652339-B2

Title: Press fitting for electrical conduit

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a continuation application of U.S. patent application Ser. No. 15/692,850, which was filed Aug. 31, 2017, now issued as U.S. Pat. No. 11,088,515, and which is incorporated herein by reference in its entirety for all purposes. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure generally relates to a press fitting for an electrical conduit. 
     BACKGROUND OF THE DISCLOSURE 
     Electrical conduits are tubes used to protect and route electrical wiring in a building or other structure. Fittings for electrical conduits including, but are not limited to: box connecters used to connect conduit to a junction or other electrical box; couplings, used to connect pieces of electrical conduit to one another when installing a run of conduit; and conduit bodies (e.g., Condulets®) used to connect pieces of electrical conduit to one another to provide pulling access in a run of conduit, to allow more bends to be made in a particular section of conduit, to conserve space where a full size bend radius would be impractical or impossible, and/or to split a conduit run into multiple directions. 
     SUMMARY OF THE DISCLOSURE 
     In one aspect, a press fitting for an electrical conduit generally comprises a fitting body having first and second open ends, and an interior surface defining a passage adapted to receive a piece of the electrical conduit therein. The fitting body includes a press-connection section that is deformable radially inward during a press connection process. A press connector is in the passage at the press-connection section of the fitting body. The press connector includes teeth adapted to engage the piece of electrical conduit received in the passage when the press-connection section is deformed radially inward during the press connection process. A conduit retainer is in the passage of the fitting body. The conduit retainer is configured to releasably grip and removably retain the piece of electrical conduit in the fitting body before the press-connection section is deformed radially inward during the press connection process. 
     In another aspect, a press fitting for an electrical conduit generally comprises a fitting body having first and second open ends. The fitting body includes a press-connection section that is deformable radially inward during a press connection process. A press connector is in the press-connection section of the fitting body. The press connector includes teeth adapted to engage the piece of electrical conduit received in the fitting body when the press-connection section is deformed radially inward during the press connection process. A socket in the fitting body apart from the press-connection section is adapted to receive a piece of electrical conduit therein. At least a section of the socket has a cross-sectional diameter that tapers in a direction away from the press-connection section. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective of one embodiment of an electrical conduit fitting constructed according to the teachings of the present disclosure; 
         FIG.  2    is a cross section of the fitting; 
         FIG.  3    is an enlarged side elevational view of a press connector of the fitting; 
         FIG.  4    is an enlarged front elevational view of a conduit retainer of the fitting; 
         FIG.  5    is a section of the conduit retainer taken in the plane defined by the line  5 - 5  in  FIG.  4   ; 
         FIG.  6    is similar to  FIG.  2   , but showing two pieces of straight, non-threaded conduit received in the fitting; 
         FIG.  7    is similar to  FIG.  2   , but showing two pieces of NPT threaded conduit received in the fitting; 
         FIG.  8    is a perspective of another embodiment of a conduit retainer; 
         FIG.  9    is a cross section of another embodiment of an electrical conduit fitting constructed according to the teachings of the present disclosure; 
         FIG.  10    is similar to  FIG.  9   , but showing two pieces of straight, non-threaded conduit received in the fitting; 
         FIG.  11    is a cross section of yet another embodiment of an electrical conduit fitting constructed according to the teachings of the present disclosure; 
         FIG.  12    is similar to  FIG.  11   , but showing two pieces of straight, non-threaded conduit received in the fitting; 
         FIG.  13    is a cross section of yet another embodiment of an electrical conduit fitting constructed according to the teachings of the present disclosure; 
         FIG.  14    is similar to  FIG.  13   , but showing two pieces of straight, non-threaded conduit received in the fitting; and 
         FIG.  15    is similar to  FIG.  13   , but showing two pieces of NPT threaded conduit received in the fitting. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     In general, the present disclosure relates to an electrical conduit press fitting—such as but not limited to, a box connector, a coupling, and a conduit body—designed and constructed to be coupled to at least one piece of electrical conduit by a press connection. The press fitting includes at least one of, but not necessarily each of: a conduit retainer for retaining a piece of conduit in the press fitting before press connection; and an alignment structure for axially aligning a piece of conduit in the press fitting before press connection. In one example, the conduit retainer is designed and constructed to include the alignment structure to also perform the alignment function. In another example, the alignment structure is separate from the conduit retainer. 
     Referring to  FIGS.  1  and  2   , one embodiment of an electrical conduit fitting constructed according to the teachings of the present disclosure is generally indicated at reference numeral 10. In general, this electrical conduit fitting  10  is in the form of a coupling designed and constructed to connect pieces of electrical conduit to one another when installing a run of conduit. It is understood that the electrical conduit fitting may be of other types, including but not limited to a box connector and a conduit body, with the teachings set forth herein with respect to the illustrated coupling applying equally to other types of conduit fittings that connect to a piece of electrical conduit by press connection. 
     Referring still to  FIGS.  1  and  2   , the electrical conduit fitting  10  includes a generally cylindrical fitting body  12  having opposing first and second open ends  14 ,  16 , and an interior surface  18  defining an internal passage extending axially along a longitudinal axis LA of the fitting body between the first and second open ends thereof. A central transverse plane CP intersects the longitudinal axis LA at a generally orthogonal angle at a mid-length of the body  12 . The fitting body  12  includes first and second press-connection sections  20 ,  22 , respectively, adjacent the respective first and second open ends  14 ,  16 , and a central portion  24  disposed between and interconnecting the first and second press-connection sections  20 ,  22 . The press-connection sections  20 ,  22  have maximum inner and outer diameters that are greater than respective inner and outer diameters of the central portion  24 . The press-connection sections  20 ,  22  have respective transition portions that step down to the decreased inner and outer diameters of the central section  24 . The press-connection sections  20 ,  22  are deformable radially inward to press fit the fitting  10  on the piece of electrical conduit. The fitting body  12  may be formed from metal, such as aluminum, steel, or other metal. The fitting body  12  may be formed from other materials. 
     A press connector  28 , a separator  30 , and a gasket  32  are received in each of the first and second press-connection sections  20 ,  22  of the fitting body  12 . The first and second open ends  14 ,  16  may include crimped or bent portions to  33  to retain the press connector  28 , the separator  30 , and the gasket  32  in each of the first and second press-connection sections  20 ,  22 , although the components may be retained in the fitting body  12  in other ways. Each of the press connector  28 , the separator  30 , and the gasket  32  are generally ring-shaped (e.g., have annular shapes) defining axial openings that are generally axially aligned and generally axially aligned with the longitudinal axis of the fitting body  12 . For each press connection section  20 ,  22 , the corresponding press connector  28 , separator  30 , and gasket  32  are adjacent to one another, with the press connector being axially outward of the gasket relative to the central transverse plane CP and the separator  30  disposed axially between the press connector and the gasket. As shown in  FIG.  3   , the press-connectors  28  may have an open or discontinuous ring shape. The separator  30  and the gasket  32  may also have this open or discontinuous ring shape. 
     Each press connector  28  includes a deformable annular body and barbs or teeth  36  (e.g., pairs or sets of barbs) extending radially inward and spaced apart from one another around the radially deformable body. As explained below, the teeth  36  are configured to engage and dig into a piece of conduit inserted into the fitting  10  during a press connection process in which the annular connection body is radially deformed (e.g., radially compressed) to connect the fitting to the piece of conduit. The press connectors  28  may be formed from metal and the teeth may be formed by punching operation or in other ways. Each gasket  32  makes a desired and suitable gas and/or liquid tight seal with the piece of conduit inserted into the fitting  10  during the press connection process. Each gasket  32  may be formed from a suitable polymer, such as rubber, or other material for making a desired and suitable gas and/or liquid tight seal with the piece of conduit inserted into the fitting during the press connection process. Each separator  30  separates the corresponding gasket  32  and press connector  28  so that the press connector does not impinge on the gasket during the press connection process. The separator  30  may include an outer surface generally corresponding with an adjacent surface of the gasket  32 . The separator  30  may be formed from metal or other material. It is understood that in one or more embodiments, the fitting  10  may not include one or more of the gasket  32  and the separator  30 . Moreover, the press-connectors  28  may be of other configurations for connection to the pieces of electrical conduit. 
     Referring to  FIGS.  2 ,  4 , and  5   , the electrical conduit fitting  10  further includes two conduit retainers, each generally indicated at reference numeral 40, received in the passage of the fitting body  12  (e.g., received in the central portion  24 ). In general, each conduit retainer  40  is configured to grip (e.g., releasably grip) and retain (e.g., removably retain) a piece of electrical conduit inserted in the fitting  10 . The conduit retainer  40  is also configured to axially align the piece of electrical conduit within the fitting  10 . It is understood that in other embodiments, the fitting may include one conduit retainer  40  or more than two conduit retainers, depending on the type of fitting and its application. In another embodiment, the two conduit retainers  40  may be combined into a single, one-piece component or otherwise connected to one another. 
     In the illustrated embodiment, the conduit retainers  40  are identical in structure and function. Each conduit retainer  40  includes a generally cylindrical or annular conduit retainer body  42  having first and second open longitudinal ends  44 ,  46 , respectively, and an internal socket  48  extending axially along an axis A of the conduit retainer body between the first and second open longitudinal ends. Each conduit retainer  40  may have an open cylindrical or annular shape, as shown in  FIG.  5   , for example. The conduit retainers  40  are received in the central portion  24  of the fitting body  12  and are generally arranged in the fitting body  12  as mirror images about the central transverse plane CP, as shown in  FIG.  2   . In particular, the second longitudinal ends  46  of the conduit retainers  40  adjacent one another (e.g., abut) generally adjacent the central transverse plane CP. The axis of the socket  48  is generally aligned with the longitudinal axis LA of the fitting body  12  and the openings defined by the respective press connectors  28 , the separators  30 , and the gaskets  32 . The first open longitudinal end  44  of each conduit retainer  40  has a flared diameter (e.g., flared inner and outer diameter) sized and shaped to engage an internal shoulder of the fitting body  12  intermediate the respective one of the first and second press-connection sections  20 ,  22  and the central portion  24 . Each conduit retainer  40  may be received in the fitting body  12  as a close clearance fit and captured between the other retainer and the corresponding gaskets  32  or may be received as a press or interference fit. The axis A of the conduit retainer  40  is generally aligned (i.e., coaxial) with the longitudinal axis LA of the fitting body  12 . The conduit retainers  40  may be attached to the fitting body  12 , such as by adhesive or a mechanical fastener. For reasons explained below, an internal conduit stop  50  at the second open longitudinal end is defined by an inner, annular curl. The conduit retainers  40  may be formed from metal, such as aluminum or steel, or plastic, or other material. 
     For each conduit retainer  40 , at least one detent (e.g., a plurality of first and second detents  52   a,    52   b ) extends radially inward from the conduit retainer body  42  and toward the axis of the body. In the illustrated embodiment, the conduit retainer  40  includes sets (e.g., pairs) of the detents  52   a,    52   b,  where the sets are spaced apart from one another around the conduit retainer body  40 . Each set includes one of the first detents  52   a  and one of the second detents  52   b.  The detents  52   a,    52   b  are deflectable (e.g., resiliently deflectable or deformable) in a radially outward direction relative to the axis A of the conduit retainer body  42 . The first detents  52   a  have radial dimensions relative to the axis A that are less than the radial dimensions of the second detents  52   b.  Thus, as shown in  FIG.  2   , the first detents  52   a  are generally aligned circumferentially and define a first effective inner diameter d 1  of the conduit retainer  40 , and the second detents  52   b  are generally aligned circumferentially and define a second effective inner diameter d 2  of the conduit retainer that is less than the first effective inner diameter. The first detents  52   a  are generally adjacent the first longitudinal end  46  and the second detents  52   b  are more adjacent the second longitudinal end  48  so that the effective inner diameter of the conduit retainer  40  tapers or decreases toward the second longitudinal end. As illustrated, this taper is a generally straight taper as shown in cross section; it is understood that in other embodiments the taper may be curviliner or other shapes in cross section. It is understood that in other embodiments, the one or more detents may define a uniform effective inner diameter that does not taper. The illustrated detents  52   a,    52   b  are integrally formed with the conduit retainer body  42 , although the detents may be formed separate and attached to the conduit retainer body. As an example, the detents  52   a,    52   b  may be formed by a punching operation. The detents  52   a,    52   b  may be of other configurations, such as flaps, or barbs, or tabs, or nubs, or springs, or other structures capable of releasably gripping a piece of electrical conduit inserted into the fitting  10 . 
     As shown in  FIGS.  6  and  7   , the detents are  52   a,    52   b  are configured to apply a gripping force on a piece of electrical conduit (e.g., both a non-threaded and a threaded electrical conduit) inserted into the fitting  10  and to axially align or center the piece of the electrical conduit in the fitting. In particular, the piece of electrical conduit EC S , EC T  engages the detents  52   a,    52   b,  causing the detents to resilient deflect (e.g., flatten). This resilient deflection imparts a spring-like gripping force on the piece of electrical conduit EC S , EC T  in the radial direction to hold the piece of electrical conduit in position in the fitting  10 . This gripping force may be overcome by applying sufficient withdrawal force on the piece of electrical conduit EC S , EC T  to remove the piece of electrical conduit from the fitting  10  if desired by the user. As can also be seen in  FIGS.  6  and  7   , the detents  52   a,    52   b  center or axially align the piece of electrical conduit EC S , EC T  in the fitting  10  (e.g., axis LA of fitting  10  is coaxial or parallel to axis P of conduit). Further, the illustrated detents  52   a,    52   b  allow the fitting  10  to be used with either the electrical conduit EC S  having a longitudinal end portion with a constant diameter (e.g., a non-threaded conduit) or the electrical conduit EC T  having a tapering longitudinal end portion (e.g., an NPT threaded conduit). This is due to the taper of the effective inner diameter defined by the different detents  52   a,    52   b.  In other embodiments, the detents  52   a,    52   b  may not define a taper but may define a uniform effective inner diameter that does not taper. 
     In use, the conduit retainer  40  retains and centers the piece of electrical conduit EC S , EC T  to aid the user in forming the conduit run, including checking lengths and arrangement of the run, before forming the permanent press connection. The stop  50  in the conduit retainer  40  also facilitates positioning the piece of electrical conduit EC S , EC T  within the fitting  10  so that the user knows depth at which the piece of conduit is inserted into the fitting (which also indicates the distance apart the two pieces of electrical conduit are in the fitting). This maximum depth of insertion and/or distance between the ends of the two pieces of electrical conduit EC S , EC T  can be communicated to the user on the fitting body  12  or elsewhere. The fitting  10  is press connected to the piece of electrical conduit EC S , EC T  using a press tool including jaws that radially press and mechanically deform the press connection sections  14 ,  16  of the fitting body  12  in a radially inward direction such that the teeth  36  of the press connector  28  engage and dig into the piece of electrical conduit. 
     Referring to  FIG.  8   , another embodiment of a conduit retainer, similar to the conduit retainer  40 , is indicated at reference numeral 140. Unless described hereinafter, this conduit retainer  140  has the same components and functions as the first conduit retainer  40 , and therefore, unless explicitly stated, the teachings set forth above with respect to the first conduit retainer apply equally to this conduit retainer. Unlike the first conduit retainer  40 , the conduit retainer body  142  of the present conduit retainer  140  includes longitudinal struts  141  extending between an interconnecting the first and second open longitudinal ends  44 ,  46 . The struts  141  are spaced apart from one another around the axis A 1  to define slot-shaped openings  143  between the struts. Each strut  141  has one of the sets (e.g., pairs) of the first and second detents  152   a,    152   b.  Each strut  141  and/or each detent  152   a,    152   b  is resiliently deflectable radially outward when the piece of electrical conduit EC S , EC T  is inserted into the conduit retainer  140  to imparts a spring-like gripping force on the piece of electrical conduit in the radial direction to hold the piece of electrical conduit in position in the fitting  10 , like the first conduit retainer  40 . The conduit retainer  140  may be received in the fitting body  12  in the same way as the conduit retainer  40 . 
     Referring to  FIGS.  9  and  10   , another embodiment of an electrical conduit fitting is generally indicated at reference numeral 210. Other than the conduit retainer  40 , this fitting  210  includes identical component as described above with respect to the first fitting  10 . Accordingly, like component are indicated by corresponding reference numerals. 
     The present fitting  210  includes at least one conduit retainer  240  (e.g., two conduit retainers) configured to grip and retain (e.g., removably retain) a piece of electrical conduit inserted into the fitting  10 . Each of the illustrated conduit retainers  240  has a generally annular or ring cross-sectional shape (e.g., an open ring shape) defining a socket  245  for receiving piece of electrical conduit. The opening  245  is generally axially aligned with the openings defined by the gasket  32 , the separator  30 , and the press connector  28 , respectively. A minimum diameter d 4  of the opening  245  is less than diameters of the openings defined by the gasket  32 , the separator  30 , and the press connector  28 , respectively. Each conduit retainer  240  is resilient and deflectable to impart a spring-like, releasable gripping force on the piece of electrical conduit in the radial direction to hold the piece of electrical conduit in position in the fitting  210 , like the first conduit retainer  40 . The conduit retainers  240  may be formed from metal or plastic or other material. The conduit retainers  240  may be captured between the fitting body  12  and the gasket  32  or may be coupled or otherwise fastened in the fitting body in other ways. In another example, one or more separators  30  may include the conduit retainer. For example, the conduit retainer may be an integral component or structure of the separator  30  or may be otherwise connected to the separator. 
     Referring to  FIGS.  11  and  12   , another embodiment of an electrical conduit fitting is generally indicated at reference numeral 310. Other than the conduit retainer  40  and the gasket  32 , this fitting  310  includes identical components as described above with respect to the first fitting  10 . Accordingly, like components are indicated by corresponding reference numerals. 
     Instead of a conduit retainer separate from the gasket, as taught by the first embodiment, the present fitting  310  includes gaskets  332  that also function as conduit retainers configured to grip and retain (e.g., removably retain) a piece of electrical conduit inserted into the fitting  10  in addition to its function as a gasket as set forth above with respect to the gasket  32 . Each gasket  332  defines an opening  345  having a reduced minimum diameter d 5  that is less than the gasket  32 . Each conduit retainer  332  is resilient and deflectable to impart a spring-like, releasable gripping force on the piece of electrical conduit in the radial direction to hold the piece of electrical conduit in position in the fitting  310 , like the first conduit retainer  40 . The gasket  240  may be formed from plastic or other material. 
     Referring to  FIGS.  13 - 15   , another embodiment of an electrical conduit fitting is generally indicated at reference numeral 410. Other than the fitting body  12 , this fitting  410  includes identical components as described above with respect to the fitting  210  described in reference to  FIGS.  9  and  10   . Accordingly, like components are indicated by corresponding reference numerals.  FIG.  13    illustrates the fitting  410  as including the conduit retainer  210 , with the understanding that the conduit retainer  240  may be omitted without necessarily departing from the scope of the present invention, as shown in  FIGS.  14  and  15   . Moreover, a different type of conduit retainer, such as a conduit retainer constructed according to the teachings of the conduit retainer  40 , may be utilized. 
     The present fitting  10  includes a fitting body  412  having a central portion  424  with a non-uniform inner cross-sectional dimension (e.g., a non-uniform inner diameter) defining an internal socket  448 . The outer cross-sectional dimension (e.g., the outer diameter) is also non-uniform, although it may be uniform in some embodiments. The interior surface  418  of the central portion  424  of the fitting body  412  includes: opposite first and second axially outer sections,  460 ,  462  adjacent the respective first and second press-connection portions  20 ,  22 ; first and second axially inner sections  464 ,  466 , juxtaposed to one another and between the first and second axially outer sections; a first transition portion  468  disposed between and interconnecting the first axially outer section  460  and the first axially inner section  464 ; and a second transition portion  470  disposed between and interconnecting the second axially outer section  462  and the first axially inner section  466 . (As used here, the terms “axially inner” and “axially outer” are relative terms in reference to the center transverse plane CP.) The illustrated embodiment shows the fitting body  412  as being formed as an integral, one-piece component. 
     The axially outer sections  460 ,  462  each define generally uniform inner diameter of the fitting body  412  is greater than an outer maximum diameter of either one of the electrical conduit EC S  having a longitudinal end portion with a constant diameter (e.g., a non-threaded conduit) or the electrical conduit EC T  having a tapering longitudinal end portion (e.g., an NPT threaded conduit). Accordingly, as shown in  FIGS.  14  and  15   , the pieces of electrical conduit EC S , EC T  are insertable into the portions of the fitting body  412  defined by the axially outer sections  460 ,  462 . The axially outer sections  460 ,  462  may facilitate centering of the electrical conduit EC S . 
     The transition portions  468 ,  470  abruptly extend radially inward toward the longitudinal axis LA to define shoulders (or stops) such that the transitions portions define an inner diameter of the fitting body  412  that is less than the inner diameter at the axially outer sections  460 ,  462 . As shown in  FIG.  14   , the minimum inner diameters of the fitting body at the transition portions are less than the outer diameter of the electrical conduit EC S  having a longitudinal end portion with a constant diameter such that the piece of electrical conduit EC S  engages the transition portion  468 ,  470  and is inhibited from further insertion toward the central transverse plane CP. The locations of the stops may be at a predetermined distance from the central transverse plane CP, which is communicated to the user, so that the user is aware of the spacing between the two pieces of electrical conduit when the two pieces are received in the fitting body  412 . 
     The axially inner sections  464 ,  466  taper inward toward the longitudinal axis LA from the respective transition portions  468 ,  470  to the central transverse plane CP. The taper of the axially inner sections  464 ,  466  generally corresponds to the taper of the end of the NPT threaded conduit such that the axially inner sections center the NPT threaded conduit in the fitting body  412 . The taper of the axially inner sections  464 ,  466  may also inhibit the NPT threaded conduit from being inserted past the central transverse plane CP. The interior surface  418  adjacent the junction of the axially inner sections  464 ,  466  may be rounded or smoothed to inhibit damaging electrical wires passing over the interior surface. 
     In other embodiments, an insert of the fitting body  412  may be used to define the socket  448  having a non-uniform (e.g., tapering) cross section. For example, inner diameter of the wall of the fitting body may be uniform and an insert having a non-uniform, tapering inner diameter defining the socket  448  may be inserted into the passage defined by the wall of the fitting body. 
     Each embodiment of the electrical conduits described herein may be designed and configured to meet the standards set forth in UL 514B. 
     Modifications and variations of the disclosed embodiments are possible without departing from the scope of the invention defined in the appended claims. 
     When introducing elements of the present invention or the embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
     As various changes could be made in the above constructions, products, and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.