ENHANCING CONNECTABILITY AMONG CONDUCTOR ELEMENTS
20190103703 ยท 2019-04-04
Inventors
Cpc classification
H01B7/282
ELECTRICITY
International classification
Abstract
Assemblies and methods are provided for establishing an electrical connection and enhancing connectability that utilize an electrical connector having a housing and a socket for receiving an electrical conductor having multiple conductor elements or conductor layers. A conductive fastener extends through the housing into the socket. The fastener can penetrate multiple conductor elements to establish an electrical connection among conductor elements. One or more of the conductor elements can include a cutaway segment that receives a conductive fastener to establish an electrical connection among the connector, fastener, and multiple conductor elements. A conductive shim may be disposed about one or more of the conductor elements and received within the cutaway segment, and the conductive fastener can engage the conductive shim to establish electrical contact among multiple conductor elements through the shim.
Claims
1. An electrical connector assembly comprising: (a) a connector having a housing that comprises (i) a first axis extending between a first end with a first opening and a second end, and (ii) a second axis transverse to the first axis, and (iii) an exterior surface; (b) a socket cavity at least partially collocated with the first opening, wherein the socket cavity (i) extends along the first axis, (ii) defines an interior surface of the housing, and (iii) is sized to receive an electrical conductor having at least two conductor elements; and (c) a passage through the housing, wherein (i) the passage extends along the second axis from the housing exterior surface to the housing interior surface, and (ii) the passage is sized to accommodate a conductive fastener, wherein (A) the conductive fastener comprises a first fastener end, a second fastener end, and a fastener first length extending between the first fastener end and the second fastener end, and wherein (B) the fastener first length is sized so that when the socket cavity receives the electrical conductor and the conductive fastener is secured within the passage, the first fastener end extends into the socket cavity and into the at least two conductor elements.
2. The electrical connector assembly of claim 1, wherein the first fastener end is a penetrating portion and the conductive fastener is selected from the group consisting of a shear bolt, a screw, or a rivet.
3. The electrical connector assembly of claim 1, wherein the first fastener end is a penetrating portion and the conductive fastener is a shear bolt having a plurality of break points.
4. The electrical connector assembly of claim 1, wherein the connector is a crimp connector.
5. The electrical connector assembly of claim 1, wherein the passage is formed by driving the conductive fastener into the housing exterior surface.
6. The electrical connector assembly of claim 4, wherein the passage is formed by driving the conductive fastener into the housing exterior surface.
7. The electrical connector assembly of claim 1, wherein (a) the housing second end includes a second opening; (b) the socket cavity defines a channel extending from the first opening to the second opening, wherein the second opening is sized to receive a second electrical conductor having at least two conductor elements; (c) the passage defines an aperture on the housing exterior surface, wherein the aperture is located a first distance from the housing first end; and wherein (d) the connector housing further comprises a second passage, wherein (i) the second passage extends along a third axis transverse to the first axis from the housing exterior surface to the housing interior surface, (ii) the second passage defines a second aperture on the housing exterior surface that is located a second distance from the first opening, wherein the second distance is greater than the first distance, and (iii) the second passage is sized to accommodate a second conductive fastener, wherein (A) the second conductive fastener comprises a third fastener end, a fourth fastener end, and a fastener second length extending between the third fastener end and the fourth fastener end, and wherein (B) the fastener second length is sized so that when the socket cavity receives the second electrical conductor and the second conductive fastener is secured within the second passage, the third fastener end extends into the socket cavity and into the at least two conductor elements of the second electrical conductor.
8. The electrical connector assembly of claim 7, wherein the first fastener end is a penetrating portion and the conductive fastener is selected from the group consisting of a shear bolt, a screw, or a rivet.
9. The electrical connector assembly of claim 8, wherein the third fastener end is a penetrating portion and the second conductive fastener is selected from the group consisting of a shear bolt, a screw, or a rivet.
10. An electrical connector assembly comprising: (a) a connector having a housing that comprises (i) a first axis extending between a first end with a first opening and a second end, and (ii) a second axis transverse to the first axis, and (iii) an exterior surface; (b) a socket cavity at least partially collocated with the first opening, wherein the socket cavity (i) extends along the first axis, (ii) defines an interior surface of the housing, and (iii) is sized to receive an electrical conductor comprising at least two conductor elements, wherein a first conductor element comprises a cutaway segment; and (c) a passage through the housing, wherein (i) the passage extends along the second axis from the housing exterior surface to the housing interior surface, and (ii) the passage is sized to accommodate a conductive fastener, wherein (A) the conductive fastener comprises a first fastener end, a second fastener end, and a fastener first length extending between the first fastener end and the second fastener end, and wherein (B) the fastener first length is sized so that when the socket cavity receives the electrical conductor and the conductive fastener is secured within the passage, the first fastener end extends into the socket cavity and establishes electrical communication with a second conductor element.
11. The electrical connector assembly of claim 10, wherein: (a) when the socket cavity receives the electrical conductor, the passage is aligned with the cutaway segment; and wherein (b) the conductive fastener establishes electrical communication with the second conductor element by extending through the passage and into the cutaway segment to engage the second conductor element.
12. The electrical connector assembly of claim 11, wherein: (a) the first conductor element and the second conductor element are concentric; and wherein (b) the cutaway segment is a notch formed by removing a portion of the first conductor element.
13. The electrical connector assembly of claim 11, wherein: (a) the first conductor element and the second conductor element are concentric; and wherein (b) the cutaway segment has a segment length extending along the first axis, and the cutaway segment is formed by removing the entire cross section of the first conductor element across the segment length.
14. The electrical connector assembly of claim 10, wherein: (a) the first conductor element and the second conductor element are concentric; (b) the cutaway segment has a segment length extending along the first axis, and the cutaway segment is formed by removing the entire cross section of the first conductor element across the segment length; (c) a conductive shim is disposed about the second conductor element at least partially within the cutaway segment, wherein the conductive shim is in electrical communication with the second conductor element; and wherein (d) the conductive fastener is in electrical communication with the second conductor element by extending through the passage to engage the conductive shim.
15. The electrical connector assembly of claim 10, wherein: (a) a conductive shim disposed at least partially within the cutaway segment, wherein the conductive shim is in electrical communication with the first conductor element; (b) the conductive fastener establishes electrical communication with the first conductor element by extending through the passage to engage the conductive shim.
16. The electrical connector assembly of claim 10, wherein: (a) a conductive shim is disposed about the first conductor element at least partially within the cutaway segment and disposed about the second conductor element, wherein the conductive shim is in electrical communication with both the first conductor element and the second conductor element; and wherein (b) the conductive fastener establishes electrical communication with both the first conductor element and the second conductor element by extending through the passage to engage the conductive shim.
17. The electrical connector assembly of claim 15, wherein the conductive shim is formed from a malleable material.
18. The electrical connector assembly of claim 15, wherein the conductive shim comprises (i) an elongated hollow body having a longitudinal axis and a shim length, and (ii) a slit in the hollow body, wherein the slit extends in the direction of the longitudinal axis and has a slit length that is less than the shim length.
19. A method for establishing an electrical connection comprising the steps of: (a) providing a connector having a housing comprising: (i) a first axis extending between a first end with a first opening and a second end, (ii) a second axis transverse to the first axis, (iii) an exterior surface; (iv) a socket cavity at least partially collocated with the first opening, wherein the socket cavity (A) extends along the first axis, (B) defines an interior surface of the housing, and (C) is sized to receive an electrical conductor comprising at least two conductor elements; and (v) a passage through the housing, wherein (A) the passage extends along the second axis from the housing exterior surface to the housing interior surface, and (B) the passage is sized to accommodate a conductive fastener; (b) providing a conductive fastener comprising first fastener end and a second fastener end; (c) inserting the electrical conductor into the first opening and into the socket cavity; and (d) inserting the conductive fastener into the passage to a depth such that the conductive fastener extends into the socket cavity to establish electrical communication with the at least two conductor elements.
20. The method for establishing an electrical connection of claim 19, wherein the conductive fastener establishes electrical communication with the at least two conductor elements by extending into the at least two conductor elements.
21. The method for establishing an electrical connection of claim 19, wherein: (a) the electrical conductor comprises a first conductor element having a cutaway segment; (b) the conductive fastener establishes electrical communication with a second conductor element by extending through the passage and into the cutaway segment to engage the second conductor element.
22. The method for establishing an electrical connection of claim 19, wherein: (a) the electrical conductor comprises a first conductor element having a cutaway segment; (b) the method further comprises the steps of: providing a conductive shim; and (ii) installing the conductive shim at least partially within the cutaway segment, wherein (A) the conductive shim is in electrical communication with a second conductor element, and wherein (B) the conductive fastener establishes electrical communication with the second conductor element by extending through the passage to engage the conductive shim.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0020] Features, aspects, and advantages of the present invention are better understood when the following detailed description of the invention is read with reference to the accompanying figures, in which:
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DETAILED DESCRIPTION
[0048] The present invention will now be described more fully hereinafter with reference to the accompanying pictures in which exemplary embodiments of the invention are shown. However, the invention may be embodied in many different forms and should not be construed as limited to the representative embodiments set forth herein. The exemplary embodiments are provided so that this disclosure will be both thorough and complete and will fully convey the scope of the invention and enable one of ordinary skill in the art to make, use, and practice the invention.
[0049] Relative terms such as lower or bottom; upper or top; upward, outward, or downward; forward or backward; and vertical or horizontal may be used herein to describe one element's relationship to another element illustrated in the figures. It will be understood that relative terms are intended to encompass different orientations in addition to the orientation depicted in the drawings. By way of example, if a component in the drawings is turned over, elements described as being on the bottom of the other elements would then be oriented on top of the other elements. Relative terminology, such as substantially or about, describe the specified materials, steps, parameters, or ranges as well as those that do not materially affect the basic and novel characteristics of the claimed inventions as whole (as would be appreciated by one of ordinary skill in the art).
[0050] Disclosed are devices and methods for improving the connectability among conductor elements in a multilayered conductor by establishing a current path among conductor elements, thereby bypassing the insulating effects of water-blocking and other insulating materials used in cable construction. The construction and configuration of electrical cables varies widely, but exemplary electrical cable embodiments are depicted in
[0051] The multitude of layers and materials surrounding the conductor elements 12 enhance the physical integrity of the cables and protect the cables from environmental conditions but have the detrimental effect of impeding electrical communication among conductor elements. Impeding electrical communication among conductor elements increases the overall resistance of the cable, which in turn leads to increased heat generation within the cable when carrying an electrical load. The increased heat is a significant contributing factor to cable failure. The problem of cable overheating is exacerbated by conventional connectors that establish an electrical connection principally with outer conductor elements or strand layers, thereby concentrating the current and heat generation in a smaller cross-sectional area of the cable.
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[0053] The devices and methods discussed herein are directed to improving the electrical resistance characteristics at conductor splice and termination points and are particularly effective for conductors that utilize water-blocking or other insulating materials. The disclosed embodiments are generally described with reference to cylindrical, shear-bolt, splice connectors utilized in combination with multilayer, stranded conductors. However, those of skill in the art will appreciate that the exemplary embodiments described herein are not intended to be limiting.
[0054] The inventive devices and techniques are generally applicable to electrical cables with multiple conductor elements, such as those shown in
[0055] Terminal connectors generally comprise a conductive partially hollow body or housing with one or more socket openings defining the interior of the housing. The socket is configured to accommodate and firmly secure the end portion of one or more cables. The socket may define a channel through the housing, or the socket can be formed from halves or shells of the connector housing joined to form a channel.
[0056] In crimp connectors, the end portions of the cables are secured in position within the connector socket by crimping the connector housing onto the cables after insertion into the socket. With shear-bolt connectors, the end portions of the cables are secured within the socket by shear bolts that extend through the connector housing to apply force to the cables. An exemplary shear-bolt, terminal connector 40 is shown in
[0057] Similarly, splice connectors generally comprise a conductive hollow body or housing with one or more socket openings configured to accommodate and secure in position the end portions of two or more cables that are to be electrically connected. An exemplary shear-bolt, splice connector 50 is shown in
[0058] To electrically couple the cables, a first cable end 62 is inserted into the first connector socket opening 53 at a first end 56 of the connector housing 51, and a second cable end 64 is inserted into the second socket opening 54 at a second end 57 of the connector. The shear-bolt fasteners 58 are threaded into the passages 59 until the shear-bolt fasteners 58 extend into the socket 52 to engage and exert pressure on the cable ends to secure the cable ends in place within the connector socket 52. The head of the shear-bolt fastener 58, and in some cases part of the stem, is designed to shear off when the bolt 58 is subjected to a predetermined torsion load. At least a portion of the shear-bolt stem remains within the passage 59 after shearing. Preferably, the bolt shears such that the stem does not extend beyond the exterior surface of the connector housing 51.
[0059] The shear bolts will commonly establish metal-to-metal contact principally or exclusively with the outer conductor elements either because the protective insulating layers were stripped during connector installation or because the pressure exerted by the shear-bolt fasteners pierced the protective insulation surrounding the outer conductor elements.
[0060] In other cases, piercing connectors are used that include serrated edges or tines within the socket that are configured to pierce the protective insulation or protective layers surrounding the outer conductor elements to establish a direct current path between the outer conductor elements and the connector housing. Establishing a current path between the outer conductor elements and the connector housing effectively lowers the electrical resistance of the outer conductor elements relative to the inner conductor elements. However, these connectors are not intended to pierce the conductor layers to provide continuity to the inner member of the strand layers.
[0061] The electrical resistance and current concentration profiles across a cross section of cable can be improved through the use of the penetrating, conductive shear fastener design shown in
[0062] The current distribution over a cable cross section improves as electrical communication is established among additional conductor elements or additional strand layers 76. However, the conductive fasteners 70 do not need to extend through all of the conductor elements or strand layers 76 to realize a significant improvement in the current concentration profile. This is in part because most of the cross-sectional area for a multi-layered cable is encompassed within the outer-most conductor elements or strand layers 76.
[0063] The embodiment of
[0064] Details of an exemplary conductive, penetrating shear-bolt fastener are shown in
[0065] Use of threaded conductive, penetrating shear-bolt fasteners 70 and multiple shear break points 88 allows the fasteners 70 to be screwed to a desired depth within the conductor elements before breaking off a portion of the fastener 70 at one of the break points 88. This allows a single conductive, penetrating shear-bolt fastener 70 to accommodate connectors and cables of varying thicknesses or cables with a varying number of strand layers 76 to be penetrated. Although threaded conductive, penetrating shear-bolt fasteners offer the advantage of convenient and precise control over penetration depth, those of skill in the art will recognize that other types of fastening means can be used to secure conductive fasteners within the connector housing and to penetrate the conductor elements, such as nails, screws, or rivets. The passages 90 can be pre-formed in the connector housing 51 or created when the conductive fasteners 70 are driven through the connector housing 51 during fabrication or installation.
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[0067] In other embodiments, the conductor elements or strand layers 76 can be modified (during splicing, for example) to enhance connectability among conductive elements or strand layers and to permit the use of either penetrating fasteners or conventional shear-bolt fasteners while still establishing a current path among conductive elements or strand layers. The exemplary embodiment shown in
[0068] The notches 102a-b are arranged in an alternating or offset fashion that corresponds to the arrangement of the fasteners 70 that extend through the connector housing 51, as illustrated in
[0069] The embodiment shown in
[0070] A conductive shim 108 is then disposed about each conductor element or strand layer 76 to replace the volume of material subtracted by removal of the circumferential segments 106. The conductive shims 108 are, thus, installed in a concentric fashion so that each shim 108 can establish electrical communication with conductive shims 108 disposed about adjacent conductor elements or strand layers 76, which creates a current path among conductor elements or strand layers 76. A conventional shear-bolt or penetrating conductive fastener 70 is driven to a depth such that it establishes electrical communication with the conductive shim 108 disposed about the outermost conductor element or strand layer 76, thereby creating a current path among conductor elements or strand layers 76 via the conductive shims 108, fasteners 70, and connector housing 51, which eliminates the need to drive the fasteners 70 to varying depths through each conductor element or strand layer 76. In this configuration, the conventional shear-bolt or conductive penetrating fasteners 70 can be driven to a constant depth that contacts the outer most conductive shim 108 while still achieving enhanced connectability among conductor elements or strand layers 76.
[0071] As an alternative to placing a separate conductive shim 108 about each conductor element or strand layer 76, a single unitary shim with a stepped or rabbeted interior surface 110 conforming to the conductive shim circumferential cutaway segments 106 can be used, as depicted in
[0072] The conductive shim 108 can be made compressible so that the shim 108 deforms to securely fit about the conductor element or strand layer 76 as the connector is crimped or secured with one or more fasteners about cable end portions 62 & 63 received within the connector socket 52. The conductive shim 108 can be formed from a compressible material or formed as a compressible helical element, as shown in
[0073] The improved connectability of connector assemblies using the present devices and methods was validated through current cycling testing. Connector assemblies with and without water blocking materials were subjected to repeated loading cycles while suspended in air in a draft free room. Test conductor loops were tested against a straight conductor segments called control conductors that were placed in series with the test loop. Each load cycle was intended to bring the control conductor temperature to 100 C. above ambient with the duration of the cycle being long enough to stabilize the temperature within +/2 C. According to industry standards, the resistance of the test loop and the temperature difference between a particular test loop and the control conductor should remain stable over the duration test through repeated load cycles.
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[0075] Similar results were reached with temperature testing, as illustrated in
[0076] The substantial improvements achieved using the inventive devices and methods described herein are illustrated in
[0077] Although the foregoing description provides embodiments of the invention by way of example, it is envisioned that other embodiments may perform similar functions and/or achieve similar results. Any and all such equivalent embodiments and examples are within the scope of the present invention.