Patent Application
20100167599
1. Field of the Invention
Embodiments of the present invention are directed to apparatuses and methods for connecting ground conductors to ground members and, more particularly, to a clamping apparatus for connecting a wide range of ground conductor sizes to a wide range of grounding member sizes.
2. Description of Related Art
Grounding clamps have been used to electrically connect electrical devices to a grounding member, such as rebar, pipe, and ground rods, in order to provide a proper ground for the electrical devices, where typically at least a portion of the grounding members are underground. More specifically, the grounding clamp is typically fastened around the grounding member by some adjustable clamping mechanism. An electrically conductive cable, i.e., a ground conductor, is attached to the grounding clamp in some manner and also attached to a ground terminal at the electrical device, thereby providing a path for any ground currents from the electrical device through the grounding clamp down the grounding member and into the ground where it can be safely dissipated.
Different grounding clamp designs have been disclosed in the prior art. Conventional grounding clamps, however, are limited by their design to accepting a narrow selection of grounding member sizes, and are often limited to only a single size grounding member. For example, a conventional ground clamp may be specially designed to accommodate only a ⅝″ diameter grounding member and a limited range of ground conductor sizes. In addition, within each clamp size there are typically two or three versions of the clamp to accommodate higher torque values, e.g., heavy duty and light duty, and/or different range of ground conductor sizes.
This specialized design approach causes suppliers to stock many different sizes and duties of clamps to meet the needs of their customers, e.g., contractors. In addition, contractors have to keep different sizes and duties of clamps on hand and have to take time to investigate each project in detail to ascertain which size and duty of ground clamp is needed at each installation site in the project.
For example, U.S. Pat. No. 5,494,462 describes a ground rod clamp made for a single specific size ground rod. The clamp has an inner region distinctly and particularly defining three different constant radii circles. A first circle has the greatest radius and is for sliding the clamp over the ground rod. This radius is greater than the radius of the ground rod to allow the clamp to slide over the rod when the rod has been damaged during installation, e.g., mushroomed by repeated hammer strikes. The second circle has a radius matched to that of the ground rod to seat the ground rod snugly in place. The third circle provides a crescent shaped space below the ground rod for ground wire(s). One problem with this design is that the clamp is sized specifically for only one size ground rod. Larger sized ground rods would not fit into the second circle to connect to the ground wire(s) below. Another problem is the third circle's crescent shaped space does not provide adequate lateral support to the ground wire(s). The ground rod must fit snugly into the second circle to prevent the ground wire(s) from coming loose and sliding past the ground member. That is, if one were to try to use a smaller ground rod, the ground wire(s) could slide by the ground rod in the extra space along side the ground rod, since the crescent shape does not provide adequate support to the ground wire(s).
What is needed is a more universal clamp having a continuously tapering shape that can accommodate a variety of grounding member sizes with a wide range of ground conductor sizes while providing lateral support to a ground conductor and that can be rated for high torque use, i.e., heavy duty, to replace the many different sizes and duties of clamps currently available.
The above and other needs are met by embodiments of the present invention which, according to one aspect, provides a universal clamping apparatus and method that can accommodate a variety of grounding member sizes with a wide range of ground conductor sizes and can be rated for high torque use, i.e., heavy duty, to replace the many different sizes and duties of clamps currently available.
One aspect of the present invention thus provides an apparatus for connecting a ground conductor to a grounding member. Such an apparatus comprises a continuous annular wall encompassing and defining an inner region adapted to have therein a connection area for the ground conductor to contact the grounding member, wherein the continuous annular wall includes an inward facing surface and an outward facing surface with respect to the inner region. The inward facing surface includes an arcuate portion having a first average radius of curvature and opposing ends. The arcuate portion is further configured so as to be concave with respect to the connection area and defines a medially-disposed aperture extending through the annular wall substantially transversely to the inner region. First and second leg portions continuously, smoothly, and uninterruptedly extend from the respective opposing ends of the arcuate portion, and cooperate with the opposing ends to define a single continuous and uninterrupted taper having a continuously increasing taper rate, without any projection inward toward the connection area, away from the arcuate portion and to respective spaced-apart leg ends. An arcuate trough portion is disposed substantially opposite to the arcuate portion and has opposing ends and a second average radius of curvature less than the first average radius of curvature. The second average radius of curvature is less than half of a distance between the spaced-apart leg ends. The trough portion is further configured so as to be concave with respect to the connection area and has a depth greater than one-third of a width thereof. An arcuate interface extends between each of the first and second leg ends and the respective opposing ends of the trough portion, wherein the arcuate interfaces are configured so as to be convex with respect to the connection area. Each arcuate interface thereby has an increased taper rate with respect to the single continuous taper of, and as the arcuate interface extends from, the respective first and second leg ends. Each arcuate interface further continuously, smoothly and uninterruptedly transitions to a decreased taper rate upon extending to the respective opposing ends of the trough portion. The arcuate interfaces thereby forms opposing lateral support members adapted to maintain the ground conductor laterally within the trough portion when the ground conductor is received thereby.
Another aspect of the present invention provides an apparatus for connecting a ground conductor to a grounding member. Such an apparatus comprises a clamp body formed from a single continuous strip of a metallic material having opposed longitudinal end portions configured to overlap such that the single strip defines an interior region adapted to have therein a connection area for the ground conductor to contact the grounding member. The clamp body further includes spaced-apart first and second legs extending substantially perpendicularly to the overlapped opposed end portions and away therefrom to respective spaced-apart leg ends. First and second trough legs extend from the respective spaced-apart leg ends and are directed away from the overlapped opposed end portions. The first and second trough legs further converge to form a trough portion of the clamp body. An aperture is defined by each of the overlapped opposed ends of the clamp body, wherein the apertures are aligned along an axis extending substantially transversely to the inner region.
Still another aspect of the present invention provides a method for connecting a ground conductor to a grounding member. Such a method comprises inserting the ground conductor through an inner region defined and encompassed by a continuous annular wall, wherein the inner region is adapted to have therein a connection area for the ground conductor to contact the grounding member. The continuous annular wall has an inward facing surface and an outward facing surface with respect to the inner region. The inward facing surface includes an arcuate portion having a first average radius of curvature and opposing ends. The arcuate portion is further configured so as to be concave with respect to the connection area and defines a medially-disposed aperture extending through the annular wall substantially transversely to the inner region. First and second leg portions continuously, smoothly, and uninterruptedly extend from the respective opposing ends of the arcuate portion, and cooperate with the opposing ends to define a single continuous and uninterrupted taper having a continuously increasing taper rate, without any projection inward toward the connection area, away from the arcuate portion and to respective spaced-apart leg ends. An arcuate trough portion is disposed substantially opposite to the arcuate portion and has opposing ends and a second average radius of curvature less than the first average radius of curvature, wherein the second average radius of curvature is less than half of a distance between the spaced-apart leg ends. The trough portion is further configured so as to be concave with respect to the connection area and has a depth greater than one-third of a width thereof. An arcuate interface extends between each of the first and second leg ends and the respective opposing ends of the trough portion, wherein the arcuate interfaces are configured so as to be convex with respect to the connection area. Each arcuate interface thereby has an increased taper rate with respect to the single continuous taper of, and as the arcuate interface extends from, the respective first and second leg ends. Each arcuate interface further continuously, smoothly and uninterruptedly transitions to a decreased taper rate upon extending to the respective opposing ends of the trough portion. The arcuate interfaces thereby forms opposing lateral support members adapted to maintain the ground conductor laterally within the trough portion when the ground conductor is received thereby. The grounding member is inserted through the inner region and moved along the inner region toward the trough portion so as to contact the ground conductor received by the trough portion. A threaded rod, threadedly engaged with the annular wall defining the aperture, is threaded toward the trough portion such that a securement end thereof provides a clamping force for clamping the grounding member against the ground conductor. The ground conductor is thereby retained with respect to the trough portion by the grounding member in cooperation with the lateral support members.
Aspects of the present invention thus provide significant advantages as further detailed herein.
Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
A side view of an apparatus for connecting a ground conductor to a grounding member, e.g., a ground clamp, is shown in
The inward facing surface 12 includes an arcuate (concave with respect to the connection area) portion 15 having a first radius of curvature. The main body 5 also includes an end 18 opposing the arcuate portion 15, wherein the inward facing wall 12 further includes an arcuate (concave with respect to the connection area) trough portion 20 opposing the arcuate portion 15 along an axis Y and having a second radius of curvature. First and second leg portions 16, 17 extend from opposing ends of the arcuate portion 15 of the inward facing surface 12. According to one aspect, the transition between each of the ends of the arcuate portion 15 and the respective first and second leg portions 16, 17 are continuous, smooth, and uninterrupted. Such a transition may occur, for example, at imaginary axis W1.
The first and second leg portions 16, 17 are further configured to cooperate with the opposing ends of the arcuate portion 15 to define a single continuous and uninterrupted taper having a continuously increasing taper rate, without any projection inward toward the connection area. The first and second leg portions 16, 17 further extend away from the arcuate portion 15 and terminate at respective spaced-apart leg ends, for example, at imaginary axis W2.
An arcuate interface (about the intersection between the inward facing wall 12 and the imaginary axis W2) extends between each of the first and second leg ends of the first and second leg portions 16, 17 and the respective opposing ends of the trough portion 20. Each arcuate interface is configured so as to be convex with respect to the connection area. As such, each arcuate interface has an increased taper rate with respect to the single continuous taper, as each arcuate interface extends from the respective first and second leg ends of the first and second leg portions 16, 17. Each arcuate interface further continuously, smoothly and uninterruptedly transitions to a decreased taper rate upon extending to the respective opposing ends of the trough portion 20. The arcuate interfaces thereby form opposing lateral support members 70 (i.e., convex with respect to the connection area within the inner region 60) adapted to maintain the ground conductor with respect to the trough portion 20, as discussed further herein.
The arcuate portion 15 of the annular wall 15 also defines a medially disposed threaded hole or aperture 30 extending therethrough. The threaded aperture 30 is configured to receive a threaded rod 40, such as a bolt or screw. The threaded rod 40 preferably comprises stainless steel or bronze. The main body 5 can optionally include support block 50 operably engaged with the arcuate portion 15 for stabilizing the clamp body 5 and adding stabilizing support around the threaded hole 30. For example, the support block 50 may provide additional threaded engagement with the threaded rod 40, which may allow a higher clamping force to be applied to the connection area by cooperation of the clamp body 5 with the threaded rod 40.
A threaded rod 40 can be threaded and advanced through the threaded hole 30 in a direction toward the trough portion 20, along the axis Y. A coarse or fine thread may be used, however a finer thread may preferred because additional torque may be realized in comparison to a coarse thread. The threaded hole 30 is preferably configured such that the axis Y bisects the trough portion 20, substantially perpendicular to imaginary axes W2 and X, as shown in
The second average radius of curvature of the trough portion 20 less than the first average radius of curvature, and may also be less than half of the distance between the spaced-apart leg ends of the first and second leg portions 16, 17. The trough portion 20 is further configured, for instance, to have a depth greater than one-third of the width thereof. For example, the trough portion 20 may have a radius of curvature of approximately 1.85 mm, though the radius of curvature may vary along the trough portion 20. In one embodiment, the second average radius of curvature of the trough portion 20 is about 2 mm. The radius of curvature of the arcuate portion 15 may be, for instance, at least 8 mm, and may also vary. In any instance, the first average radius of curvature of the arcuate portion 15 is greater than the second average radius of curvature of the trough portion 20.
Since the second average radius of curvature of the trough portion 20 is less than half the distance between the spaced-apart leg ends of the first and second leg portions 16, 17, lateral support members 70 (whereby the inward facing wall 12 extends toward the connection area) are formed by the arcuate interfaces therebetween. In this manner, the lateral support members 70 provide lateral support for a ground conductor received by the trough portion 20, as more particularly discussed with respect to
As shown in
As shown in
As previously discussed, the first and second leg portions 16, 17 are configured to cooperate with the opposing ends of the arcuate portion 15 to define a single continuous and uninterrupted taper having a continuously increasing taper rate, without any projection inward toward the connection area, as the first and second leg portions 16, 17 extend away from the arcuate portion 15 toward the respective spaced-apart leg ends leading to the lateral support members 70. In some aspects, the interface between the first and second leg portions 16, 17 and the arcuate portion 15 may occur at imaginary axis W1, which may correspond to the widest point of the inward facing surface 12. The first and second leg portions 16, 17 continuously and uninterruptedly taper inward toward the connection area (i.e., concave with respect to the connection area) such that the taper rate continuously increases toward the lateral support members 70. With such a configuration, aspects of the present invention include an inward facing surface 12 without any substantial inward protrusions, except for the lateral support members 70, toward the connection area within the inner region 60. As also previously discussed, the particular configuration of the inward facing surface 12 thereby facilitates the application of a clamping force to form a connection between one or more grounding members ranging in size and one or more ground conductors ranging in size.
As illustrated in
Accordingly, the main body 5 is dimensioned to accept the variety of combinations. For example, as shown in
Moreover, referring again to
In one instance, the main body 5 may be configured such that, upon the trough portion 20 receiving the smallest size ground conductor 80, the leg ends of the first and second leg portions 16, 17 are configured to be spaced apart so as to be capable of receiving the largest width grounding member 90 therebetween such that the largest width grounding member 90 contacts the smallest size ground conductor 80 and cooperates with the lateral support members 70 to retain the smallest size ground conductor 80 with respect to the trough portion 20.
The main body 5 can be comprised of metal alloy that comprises at least 80% copper. In one instance, the main body 5 is cast as a monolithic structure of a metallic material. It will be understood, however, that other materials, including non-metallic materials, can be used to for the main body 10 in addition to or instead of a metal alloy. In a preferred embodiment, the composition of the main body 5 includes approximately 85% copper. The remaining 15% preferably includes a combination of aluminum and lead. The thickness C of the wall 10 is preferably approximately 2.7 mm, but may be more or less. Tests have shown that this composition allows the main body 5 of the ground clamp to maintain structural integrity when a torquing force of up to 300 inch-pounds is applied to the threaded rod 40, which is considered a heavy duty ground clamp in the art. It should be appreciated that other compositions are possible and that the ground clamp may be made for lighter duty to save on material costs, or can be made for heavier duty such as up to 700 inch-pounds. For example, the thickness C may be less than 2.7 mm. The copper content may be 80% or more and/or other metals or non-metals may be used in the main body 5 in combination with the copper.
In an alternative embodiment, as shown in
According to aspects of the present invention, each of the first and second trough legs 160, 170 defines an angle of between about 30 degrees and about 70 degrees with the axis 210. That is, the angle between each of the first and second trough legs 160, 170 and the axis 210 is between about 30 degrees and about 70 degrees. In one embodiment, the angle between each of the first and second trough legs 160, 170 and the axis 210 is about 50 degrees.
Since the opposed end portions 110, 120 overlap, one of the end portions comprises an inwardly disposed end portion 110 and the other end portion comprises an outwardly disposed end portion 120 with respect to the connection area within the inner region 130. In such instances, the aperture 200 defined by the outwardly disposed end portion 120 is no smaller than (i.e., is equal to or greater than) the aperture 190 defined by the inwardly disposed end portion 110. When the end portions 110, 120 are overlapped, the apertures 190, 200 may be aligned along the axis 210 as the clamp body 100 is formed in the folding or stamping process. In some instances, the folding or stamping process, in conjunction with the properties of the material comprising the clamp body 100 may be sufficient to retain the end portions 110, 120 in the overlapped position, with the apertures 190, 200 remaining aligned along the axis 210. In other instances, however, the overlapped inwardly disposed and outwardly disposed end portions 110, 120 may be secured together such as, for example, by welding (i.e., by spot welding) or in other manners (i.e., by an adhesive), so as to retain the apertures 190, 200 aligned along the axis 210, to form the clamp body 100, and to define the inner region 130.
In one embodiment, the inwardly disposed end portion 110 defining the corresponding aperture 190 may be drawn away from the connection area (i.e., outwardly of the inner region 130) while the aperture 190 is formed, for example, as the aperture 190 is punched. In such instances, the drawn feature of the inwardly disposed end portion 110 may be configured to extend through the aperture 200 defined by the outwardly disposed end portion 120, which serves to align the aperture 200 defined by the outwardly disposed end portion 120 with the aperture 190 defined by the inwardly disposed end portion 110, as shown in
According to another aspect, the clamp body 100 may be formed such that the trough portion 180 is defined by a radius of curvature, similar to that disclosed in conjunction with the embodiment shown in
In any instance, the metallic material of the clamp body 100 may comprise, for example, stainless steel. However, one skilled in the art will appreciate that the clamp body 100 may be formed of any suitable material, whether metallic or nonmetallic, capable of being folded or stamped into a configuration as disclosed.
Installation of a ground clamp according to various aspects and embodiments of the present invention defines a method for connecting a ground conductor to a grounding member. Such a method includes inserting a grounding member through an inner region of a grounding apparatus, such as disclosed above in the several aspects of the present invention, inserting a ground conductor through the inner region and into a trough portion of the grounding apparatus, and threadedly advancing a threaded rod through a threaded hole of the grounding apparatus to force the grounding member against the ground conductor disposed within the trough portion. In this manner, the ground conductor is securedly maintained and retained within the trough portion with the lateral support members providing lateral support for the ground conductor.
Many modifications and other embodiments of the invention set forth herein will come to mind to one skilled in the art to which the invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. For example, each of the embodiments shown in
This application is a divisional of U.S. patent application Ser. No. 11/933,794, filed Nov. 1, 2007, which is a continuation-in-part of U.S. patent application Ser. No. 10/935,569, filed Sep. 7, 2004, which claims priority to U.S. Provisional Patent Application No. 60/500,494, filed on Sep. 5, 2003, the entire contents of which are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60500494 | Sep 2003 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11933794 | Nov 2007 | US |
| Child | 12580533 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10935569 | Sep 2004 | US |
| Child | 11933794 | US |
