U-shaped pull box

A pull box for accepting cable in electrical wiring installations includes a main body. The main body includes a first leg, a second leg, and a bridge portion spanning between and interconnecting the first leg and the second leg. The first leg, the second leg, and the bridge portion form a U-shape and define an interior space. The pull box further includes a cover. The cover is movable relative to the housing to transition the pull box between an open state and a closed state. The cover permits access to the interior space when the pull box is in the open state and prevents access to interior space when the pull box is in the closed state.

FIELD OF INVENTION

The present disclosure relates to electrical wiring installations. More particularly, the present disclosure relates to a pull box having a U-shape.

BACKGROUND

Pull boxes are known in the field of electrical wiring. A pull box may be provided in a wiring installation to facilitate the pulling of cables through a conduit. Additionally, pull boxes may be provided to act as a splice box, protect conductors in threaded rigid conduit, connect lengths of conduit, or to provide access to conductors for maintenance and future system changes. Known pull boxes may be provided in a square, rectangular, cylindrical, or L-shaped configuration.

In certain applications, it is necessary or desired to run cable along a U-shaped pathway. Pull boxes of the square, rectangular, or cylindrical configuration may satisfactorily provide or accommodate such U-shaped pathway. The use, however, of these pull box configurations in U-shaped wiring pathways may present drawbacks. For example, an oversize pull box may need to be used to accommodate the minimum bend radius mandated by electrical codes for U-shaped cable runs. The use of the oversized pull box may increase the costs of the wiring installation. Additionally, the oversize pull box occupies an unnecessarily large amount of space, which may be undesirable in compact installation environments.

While it is possible to construct a wiring enclosure that approximates a U-shape using multiple known fittings, this option is undesirable due to the high cost associated with using multiple fittings, as well as the large amount of time that is required to assemble the fittings.

SUMMARY OF THE INVENTION

In one embodiment, a pull box for accepting cable in electrical wiring installations includes a main body. The main body includes a first leg, a second leg, and a bridge portion spanning between and interconnecting the first leg and the second leg. The first leg, the second leg, and the bridge portion form a U-shape and define an interior space. The pull box further includes a cover. The cover is movable relative to the housing to transition the pull box between an open state and a closed state. The cover permits access to the interior space when the pull box is in the open state and prevents access to interior space when the pull box is in the closed state.

In another embodiment, a method of installing electrical wiring includes providing a U-shaped pull box having a first leg, a second leg, a bridge portion spanning between and interconnecting the first leg and the second leg, and a cover connected to the bridge portion. The method also includes providing a cable, and running the cable through the first leg and into the bridge portion. The method further includes opening the cover, redirecting the cable through the second leg, and closing the cover.

In yet another embodiment, a wire installation includes a U-shaped pull box having a first leg, a second leg, a bridge portion spanning between and interconnecting the first and the second leg, and a cover connected to the bridge portion. The bridge portion has an interior surface that is a continuously curved surface having a first radius of curvature. The cover is moveable between an opened position and a closed position. A cable runs through the first leg, the bridge portion, and the second leg. The cable is bent to the first radius of curvature.

DETAILED DESCRIPTION

FIGS.1-8show an exemplary embodiment of a U-shaped pull box100. The pull box100includes a first side102and a second side104that each extend between a first end106and a second end108. The pull box100includes a main housing110and a cover112. The main housing110and the cover112may be of any desired material including, without limitation, aluminum, coated PVC, feraloy, stainless steel, and copper.

The main housing110includes a flange114. The flange114defines an opening116. In the illustrated embodiment, the opening116is substantially stadium shaped. In alternative embodiments, the opening may be any desired shape. A first leg118, a second leg120, and a bridge portion122extend from the flange114. The first leg118is provided at the first end106of the pull box100. The second leg120is provided at the second end108of the pull box100. The bridge portion122spans between and interconnects the first leg118and the second leg120. The first leg118, the bridge portion122, and the second leg120cooperate to define an interior space124. The opening116defined by the flange114provides access to the interior space124.

The first leg118and the second leg120extend substantially parallel to one another and perpendicular relative to a longitudinal axis of the flange114. The bridge portion122is substantially arcuate, and is convex relative to the flange114. Thus, in the illustrated embodiment, the first leg118, the second leg120, and the bridge portion122form a U-shape. In alternative embodiments, the first leg, the second leg, and the bridge portion may form any desired shape.

The bridge portion122includes an interior surface126and an exterior surface128. In the illustrated embodiment, the interior surface126is a continuously curved surface having a radius of curvature (R) that is greater than the minimum bend radius for cable (C) that is run through the pull box100. In an alternative embodiment, the interior surface may have any desired radius of curvature. In another alternative embodiment, the interior surface may be composed of a plurality of straight segments that are arranged to approximate a desired radius of curvature.

A brace130is provided on the exterior surface128of the bridge portion122. In the illustrated embodiment, the brace130is provided as a single, continuous, V-shaped rib that is located midway between the first side102and the second side104of the pull box100, and extends between the first leg118and the second leg120. In an alternative embodiment, the brace may be discontinuous (i.e., made of separate, discrete rib segments), or terminate prior to reaching the first leg or the second leg. In another alternative embodiment, the brace may be any desired shape. For example, the brace may be a U-shaped rib. In yet another alternative embodiment, the brace may be offset toward the first side or the second side of the pull box. In still yet another alternative embodiment, the bridge portion may be provided with multiple braces. In still yet even another alternative embodiment, the brace may be omitted.

The brace130includes a first aperture132and a second aperture134. The first and second apertures132,134may, for example, receive a fastener (not shown) for mounting the main housing110to a desired structure or may be used to mount a tag (not shown). The first and second apertures132,134are provided on opposite sides of the peak of the V-shaped brace130. In an alternative embodiment, the brace may include a fewer or greater number of apertures. In another alternative embodiment, the first and second apertures may be provided on any desired location of the brace. In yet another alternative embodiment, the apertures may be omitted.

The first leg118and the second leg120are provided with a first mounting tab136and a second mounting tab138, respectively. The first mounting tab136and the second mounting tab138are provided on a side of the respective leg118,120opposite to the side of the leg on which the brace130is provided. In other words, the first and second mounting tabs136,138extend from the first and second legs118,120, respectively away from the brace130. Each of the first mounting tab136and the second mounting tab138is provided with an aperture140,142that may, for example, receive a fastener (not shown) for mounting the main housing110to a desired structure or be used to assemble a ground lug (not shown). In an alternative embodiment, the main housing may include a fewer or greater number of mounting tabs. In another alternative embodiment, the mounting tabs may be provided at any desired location on the main housing. In still yet other alternative embodiments, the apertures, or the first and second mounting tabs themselves, may be omitted.

A first inlet140is provided at an end of the first leg118, and a second inlet142is provided at an end of the second leg120. Each of the first inlet140and the second inlet142is in communication with the interior space124. The first inlet140and the second inlet142are each provided with a connection mechanism144,146. The connection mechanism144,146is provided to allow a conduit or any other desired external structure to be attached to the first inlet140or the second inlet142. In one example embodiment, the connection mechanism144,146is an internal national pipe thread. In alternative embodiments, the first inlet or the second inlet may be provided with any desired connection mechanism. Non-limiting examples of connection mechanisms including external national pipe thread, Millimetric threads, and compression fittings. In other alternative embodiments, the connection mechanism may be omitted.

The cover112includes a flange148. The flange148defines an opening150. In the illustrated embodiment the cover opening150is substantially the same as the main housing opening116(i.e., stadium shaped). In alternative embodiments, the flange opening may be any desired shape.

A raised portion152extends from the flange148. The raised portion152defines an interior space153. In the illustrated embodiment, the raised portion152is substantially arcuate shaped and arranged to be concave relative to the flange148. In alternative embodiments, the raised portion may be any desired shape. In other alternative embodiments, the raised portion may be omitted and the entire cover may be substantially planar.

The cover flange148is provided with a groove154for receiving a gasket156. In the illustrated embodiment, the groove154is substantially stadium shaped so as to mimic the shape of the cover opening150. In alternative embodiments the groove may have any desired shape. In another alternative embodiment, the groove may be provided on the main housing flange rather than the cover flange. In yet another alternative embodiment, the groove may be omitted.

The pull box100includes first and second hinges158,160for attaching the cover112to the main housing110. The first and second hinges158,160may be made out of any desired material including, without limitation, stainless steel, aluminum, and copper. The first hinge158is attached to the main housing flange114and the cover flange148on the first side102of the pull box100toward the first end106. The second hinge160is attached to the main housing flange114and the cover flange148on the first side102of the pull box100and toward the second end108. In an alternative embodiment, the pull box may include a fewer or greater number of hinges. In another alternative embodiment, the hinges may be provided at any desired location on the pull box. In another alternative embodiment, the hinges may be omitted.

The hinges158,160permit the cover112to pivot relative to the main housing110to transition the pull box100between an open state (FIG.1) and a closed state (FIG.2). In the open state, the cover112does not obstruct the opening116of the main housing110, thereby permitting access to the interior space124of the main housing110. In the closed state, the cover112obstructs the opening116of the main housing110, thereby preventing access to the interior space124.

The cover112and the main housing110are arranged and configured such that, in the closed state, the combined volume of the interior space153of the cover112and the interior space124of the main housing110provide the pull box100with an interior volume that is at least the interior volume required by Pemex, UL, or NEC standards. Additionally, in the closed state, the cover flange148cooperates with the main housing flange114to define a flame path. The156, which is received in the groove154on the cover flange148, engages with the main housing flange114to prevent foreign contaminants from entering the pull box100.

The pull box100may be provided with a locking mechanism162to maintain the pull box in the closed state. In the illustrated embodiment, the locking mechanism162is provided as six bolts that extend through apertures164on the cover flange148and engage with internal threads provided in apertures166on the main housing flange114. In alternative embodiments, the pull box may include a greater or fewer number of bolts, and the apertures for receiving the bolts may be provided at any desired location. In other alternative embodiments, the locking mechanism may be provided as any desired arrangement. For example, the locking mechanism may be provided as a clamp, or as an adhesive that is applied to the cover flange or the main housing flange. In yet another alternative embodiment, the locking mechanism may be omitted.

An exemplary method of using the pull box100will now be described. First, the pull box100is attached to a desired structure using fasteners that extend through the apertures132,134on brace130and the apertures140,142on first and second mounting tabs136,138. Next, a first conduit is attached to the first inlet140of the first leg118using the respective connection mechanism144, and a second conduit is attached to the second inlet142of the second leg120using the respective connection mechanism146. Then, a cable (C) is run through the first conduit, the first leg118, and into the bridge portion122.

With the pull box100in the open state, the cable may (C) be accessed through the opening116of the main housing110, and redirected into the second leg120and through the second conduit. During this, the cable (C) may be manipulated so as to be forced into contact with the interior surface126of the bridge portion122. Due to the specifically selected radius of curvature (R) for the interior surface126, this contact prevents the cable (C) from being worked into a curve that is less than the minimum bend radius for that specific cable (C). The cover112may then be moved relative to the main housing110to transition the pull box110to the closed state. Finally, the locking mechanism162may be used to secure the cover112to the main housing110to maintain the pull box110in the closed state.

The foregoing method is merely exemplary. Any of the individual steps may be changed or omitted, and the order in which the steps are performed may be changed. For example, the first and second conduit may be attached to the first inlet or the second inlet before the main housing is attached to a desired structure. As another example, the step of attaching the first conduit or the second conduit may be omitted. As yet another example, the cover may be moved to the closed position before the cable is run through the pull box, and the redirecting of the cable may occur through contact with the raised portion of the cover.