This invention relates generally to electrical connectors, and more particularly, to power utility connectors for mechanically and electrically connecting a tap or distribution conductor to a main electrical transmission conductor.
Electrical utility firms constructing, operating and maintaining overhead and/or underground power distribution networks and systems utilize connectors to tap main power transmission conductors and feed electrical power to distribution line conductors, sometimes referred to as tap conductors. The main power line conductors and the tap conductors are typically high voltage cables that are relatively large in diameter, and the main power line conductor may be differently sized from the tap conductor, requiring specially designed connector components to adequately connect tap conductors to main power line conductors. Generally speaking, three types of connectors are commonly used for such purposes, namely bolt-on connectors, compression-type connectors, and wedge connectors.
Bolt-on connectors typically employ die-cast metal connector pieces or connector halves formed as mirror images of one another, sometimes referred to as clam shell connectors. Each of the connector halves defines opposing channels that axially receive the main power conductor and the tap conductor, respectively, and the connector halves are bolted to one another to clamp the metal connector pieces to the conductors. Such bolt-on connectors have been widely accepted in the industry primarily due to their ease of installation, but such connectors are not without disadvantages. For example, proper installation of such connectors is often dependent upon predetermined torque requirements of the bolt connection to achieve adequate connectivity of the main and tap conductors. Applied torque in tightening the bolted connection generates tensile force in the bolt that, in turn, creates normal force on the conductors between the connector halves. Applicable torque requirements, however, may or may not be actually achieved in the field and even if the bolt is properly tightened to the proper torque requirements initially, over time, and because of relative movement of the conductors relative to the connector pieces or compressible deformation of the cables and/or the connector pieces over time, the effective clamping force may be considerably reduced. Additionally, the force produced in the bolt is dependent upon frictional forces in the threads of the bolt, which may vary considerably and lead to inconsistent application of force among different connectors.
Compression connectors, instead of utilizing separate connector pieces, may include a single metal piece connector that is bent or deformed around the main power conductor and the tap conductor to clamp them to one another. Such compression connectors are generally available at a lower cost than bolt-on connectors, but are more difficult to install. Hand tools are often utilized to bend the connector around the cables, and because the quality of the connection is dependent upon the relative strength and skill of the installer, widely varying quality of connections may result. Poorly installed or improperly installed compression connectors can present reliability issues in power distribution systems.
Wedge connectors are also known that include a C-shaped channel member that hooks over the main power conductor and the tap conductor, and a wedge member having channels in its opposing sides. The wedge member is driven through the C-shaped member, deflecting the ends of the C-shaped member and clamping the conductors between the channels in the wedge member and the ends of the C-shaped member. An application tool is used to drive the wedge member to a proper position with respect to the channel member to achieve a repeatable, consistent connection with the conductors. One such wedge connector is commercially available from Tyco Electronics Corporation of Harrisburg, Pa. and is known as an AMPACT Tap or Stirrup Connector. AMPACT connectors include different sized channel members to accommodate a set range of conductor sizes, and multiple wedge sizes for each channel member. Each wedge accommodates a different conductor size. As a result, AMPACT connectors tend to be more expensive than either bolt-on or compression connectors due to the increased part count. For example, a user may be required to possess three channel members that accommodate a full range of conductor sizes. Additionally, each channel member may require up to five wedge members to accommodate each conductor size for the corresponding channel member. As such, the user must carry fifteen connector pieces in the field to accommodate the full range of conductor sizes. The increased part count increases the overall expense and complexity of the AMPACT connectors.
AMPACT connectors are believed to provide superior performance over bolt-on and compression connectors. For example, the AMPACT connector results in a wiping contact surface that, unlike bolt-on and compression connectors, is stable, repeatable, and consistently applied to the conductors, and the quality of the mechanical and electrical connection is not as dependent on torque requirements and/or relative skill of the installer. Additionally, and unlike bolt-on or compression connectors, because of the deflection of the ends of the C-shaped member some elastic range is present wherein the ends of the C-shaped member may spring back and compensate for relative compressible deformation or movement of the conductors with respect to the wedge and/or the C-shaped member.
It would be desirable to provide a lower cost, more universally applicable alternative to conventional wedge connectors that provides superior connection performance to bolt-on and compression connectors.
In one aspect, a wedge connector assembly is provided including a spring member having a generally C-shaped body with an inner surface, and a wedge member having opposed first and second sides. The wedge member is mated with the spring member such that the wedge member is configured to securely retain a first conductor between the first side and the spring member and a second conductor between the second side and the spring member. The wedge member has at least two final mating positions.
Optionally, the wedge member may have two orientations, namely a first orientation and a second orientation, wherein the first and second sides are flipped with respect to one another in the first and second orientations. A top of the wedge member may engage the inner surface in the first orientation and a bottom of the wedge member may engage the inner surface in the second orientation. Optionally, the wedge member may include a leading end and a notch extending inward from the leading end. The notch may also extend inward from one of top and the bottom. Optionally, the spring member may include a channel, wherein the wedge member is initially loaded into the channel during mating, and wherein the initial loading orientation of the wedge member with respect to the spring member is reversible. The wedge member may be configured to be loaded to the at least two final mating positions using the same application tool.
In another aspect, a wedge connector assembly is provided including a spring member having a generally C-shaped body having an inner surface, and a wedge member having a top, a bottom and opposed sides tapered between a leading end and a trailing end. The wedge member has a notch extending from the leading end along the bottom, wherein the notch has an open face at the leading end and a base wall generally opposed to the open face. The wedge member is configured to be mated to a first mated depth when the notch is in a first orientation with respect to the spring member and the wedge member is configured to be mated to a second mated depth when the notch is in a second orientation with respect to the spring member.
In a further aspect, a wedge connector assembly is provided including a spring member having a generally C-shaped body having an inner surface and an outer surface. The assembly also includes a wedge member having a top, a bottom and opposed sides tapered between a leading end and a trailing end. One of the spring member and the wedge member has an opening, and the other of the spring member and the wedge member has a barb extending from a surface thereof. The barb is received within a respective opening to define a mating position when the wedge member is mated with the spring member. The wedge member has at least two final mating positions.
The wedge member 58 may be installed with special tooling having for example, gunpowder packed cartridges, and as the wedge member 58 is forced into the spring member 56, the ends of the spring member 56 are deflected outwardly and away from one another via the applied force FA shown in
As shown in
I=HW+D1+D2−HC (1)
With strategic selection of HW and HC the actual interference I achieved may be varied for different diameters D1 and D2 of the conductors 52 and 54. Alternatively, HW and HC may be selected to produce a desired amount of interference I for various diameters D1 and D2 of the conductors 52 and 54. For example, for larger diameters D1 and D2 of the conductors 52 and 54, a smaller wedge member 58 having a reduced height HW may be selected. Alternatively, a larger spring member 56 having an increased height HC may be selected to accommodate the larger diameters D1 and D2 of the conductors 52 and 54. As a result, a user requires multiple sized wedge members 52 and/or spring members 56 in the field to accommodate a full range of diameters D1 and D2 of the conductors 52 and 54. Consistent generation of at least a minimum amount of interference I results in a consistent application of applied force FA which will now be explained in relation to
The tap conductor 102, sometimes referred to as a distribution conductor, may be a known high voltage cable or line having a generally cylindrical form in an exemplary embodiment. The main conductor 104 may also be a generally cylindrical high voltage cable line. The tap conductor 102 and the main conductor 104 may be of the same wire gauge or different wire gauge in different applications and the connector assembly 100 is adapted to accommodate a range of wire gauges for each of the tap conductor 102 and the main conductor 104.
When installed to the tap conductor 102 and the main conductor 104, the connector assembly 100 provides electrical connectivity between the main conductor 104 and the tap conductor 102 to feed electrical power from the main conductor 104 to the tap conductor 102 in, for example, an electrical utility power distribution system. The power distribution system may include a number of main conductors 104 of the same or different wire gauge, and a number of tap conductors 102 of the same or different wire gauge. The connector assembly 100 may be used to provide tap connections between main conductors 104 and tap conductors 102 in the manner explained below.
As shown in
The C-shaped spring member 108 includes a first hook portion 130, a second hook portion 132, and a central portion 134 extending therebetween. The spring member 108 further includes an inner surface 136 and an outer surface 138. The spring member 108 forms a chamber 140 defined by the inner surface 136 of the spring member 108. The conductors 102, 104 and the wedge member 106 are received in the chamber 140 during assembly of the connector assembly 100. In the illustrated embodiment, the top 114 of the wedge member 106 generally faces and/or engages the inner surface 136 of the central portion 134. Alternatively, as described in further detail below, the wedge member 106 may be oppositely oriented, or flipped, within the chamber 140 such that the bottom 116 of the wedge member 106 generally faces and/or engages the inner surface 136 of the central portion 134.
In an exemplary embodiment, the first hook portion 130 forms a first contact receiving portion or cradle 142 positioned at an end of the chamber 140. The cradle 142 is adapted to receive the tap conductor 102 at an apex 144 of the cradle 142. A distal end 146 of the first hook portion 130 includes a radial bend that wraps around the tap conductor 102 for about 180 circumferential degrees in an exemplary embodiment, such that the distal end 146 faces toward the second hook portion 132. Similarly, the second hook portion 132 forms a second contact receiving portion or cradle 150 positioned at an opposing end of the chamber 140. The cradle 142 is adapted to receive the main conductor 104 at an apex 152 of the cradle 150. A distal end 156 of the second hook portion 132 includes a radial bend that wraps around the main conductor 104 for about 180 circumferential degrees in an exemplary embodiment, such that the distal end 156 faces toward the first hook portion 130. The spring member 108 may be integrally formed and fabricated from extruded metal in a relatively straightforward and low cost manner.
A notch 166 extends into the body 160 from the leading end 162 and from the bottom 116. In the illustrated embodiment, the notch 166 is box-shaped and is defined by side walls 168, a top wall 170 and a base wall 172. The notch 166 has an open face at the leading end 162 and another open face at the bottom 116. The side walls 168 extend from the open face at the leading end 162 to the base wall 172, and are parallel to the sides 110, 112 of the wedge member 106. The top wall 170 extends from the open face at the leading end 162 to the base wall 172, and is parallel to the top 114 of the wedge member 106. The base wall 172 extends from the open face at the bottom 116 to the top wall 170, and is parallel to the leading end 162. Other shaped notches are possible in alternative embodiments. The notch 166 has a length Ln measured from the open face at the leading end 162 to the base wall 172, a width Wn measured between the opposed side walls 168, and a thickness Tn measured from the open face at the bottom 116 to the top wall 170. In an exemplary embodiment, the notch 166 is sized and shaped to receive a portion of an application tool to control a mating depth of the wedge member 106 with respect to the spring member 108 (shown in
An exemplary operation of the wedge connector assembly 100 will be described with reference to
The spring member 108 includes a leading edge 180 and a trailing edge 182. The first and second hook portions 130 and 132 are tapered from the trailing edge 182 to the leading edge 180. The spring member 108 has a length Ls measured between the leading edge 180 and the trailing edge 182. In an exemplary embodiment, the length Ls is between approximately one and a half and two inches. The spring member length Ls is less than the wedge member length Lw such that the wedge member 106 may be positioned at multiple positions with respect to the spring member 108 during use of the connector assembly 100, as will be described in further detail below.
The wedge member 106 and the spring member 108 are separately fabricated from one another or otherwise formed into discrete connector components and are assembled to one another as explained below. While one exemplary shape of the wedge and spring members 106, 108 has been described herein, it is recognized that the members 106, 108 may be alternatively shaped in other embodiments as desired.
During assembly of the connector assembly 100, the tap conductor 102 and the main conductor 104 are positioned within the chamber 140 (shown in
The wedge member 106 may be loaded in more than one orientation. In a first orientation, as illustrated in
The final mated position of the wedge member 106 is based on the initial loading orientation of the wedge member 106. The first orientation corresponds to a first final mated position, which is illustrated in
As illustrated in
In the first final mated position, the tap conductor 102 is captured between the channel 118 of the wedge member 106 and the inner surface 136 of the first hook portion 130. Likewise, the main conductor 104 is captured between the channel 120 of the wedge member 106 and the inner surface 136 of the second hook portion 132. As the wedge member 106 is pressed into the chamber 140 of the spring member 108, the hook portions 130, 132 are deflected outward. The spring member 108 is elastically and plastically deflected resulting in a spring back force to provide a clamping force on the conductors 102, 104. A large application force, on the order of about 4000 lbs of clamping force is provided in an exemplary embodiment, and the clamping force ensures adequate electrical contact force and connectivity between the connector assembly 100 and the conductors 102, 104. Additionally, elastic deflection of the spring member 108 provides some tolerance for deformation or compressibility of the conductors 102, 104 over time, such as when the conductors 102, 104 deform due to compression forces. Actual clamping forces may be lessened in such a condition, but not to such an amount as to compromise the integrity of the electrical connection.
As illustrated in
In the second final mated position, the tap conductor 102 is captured between the channel 120 of the wedge member 106 and the inner surface 136 of the first hook portion 130. Likewise, the main conductor 104 is captured between the channel 118 of the wedge member 106 and the inner surface 136 of the second hook portion 132. As the wedge member 106 is pressed into the chamber 140 of the spring member 108, the spring member 108 is elastically and plastically deflected resulting in a spring back force to provide a clamping force on the conductors 102, 104, in a similar manner as described above. Because the amount of travel of the wedge member 106 is greater when the wedge member 106 is in the second orientation, the portion of the wedge member 106 received within the envelope of the spring member 106 is generally wider. As such, the wedge member 106 may accommodate different, smaller sized conductors 102, 104 when the wedge member 106 is in the second orientation. The wedge member 106 may provide a relatively larger application or clamping force between the connector assembly 100 and the conductors 102, 104 when the wedge member 106 is in the second orientation.
The first and second barbs 208, 210 each include a leading ramp surface 212 facing the leading end 162, and a rear surface 214 facing the trialing end 164. The rear surface 212 extends substantially perpendicular to the respective top 114 or bottom 116. A planar outer surface 216 extends between the leading ramp surface 212 and the rear surface 214. The outer surface 216 is oriented substantially parallel to the top 114 or bottom 116. The barbs 208, 210 may have other shapes in alternative embodiments. For example, the leading ramp surface 212 may be curved, may have a more gradual slope than the slope depicted, may have a steeper slope than the slope depicted, or may be provided in multiple sections having different slopes. The rear surface 214 may be non-perpendicular with respect to the top 114 or the bottom 116, and may be sloped. Optionally, the rear surface 214 may be sloped in the opposite direction as the leading ramp surface 212, or alternatively, the rear surface 214 may be sloped in the same direction as the leading ramp surface 212. Optionally, the barbs 208, 210 may be devoid of an outer surface 216 such that the leading ramp surface 212 extends to the rear surface 214. The barbs 208, 210 extend outward from the top 114 and bottom 116, respectively for a distance 218. Optionally, the distance 218 may be different for the first barb 208 than the second barb 210.
An exemplary operation of the wedge connector assembly 100 will be described with reference to
The spring member 220 is similar to the spring member 108, and like reference numerals are used to identify like components. The spring member 220 includes the first hook portion 130, the second hook portion 132, and the central portion 134 extending therebetween. The spring member 220 forms the chamber 140 (shown in
The spring member 220 includes an opening 222 extending through the central portion 134. The opening 222 is sized, shaped and positioned to receive either the first barb 208, such as when the wedge member 206 is positioned in the first orientation (
During assembly, the tap conductor 102 and the main conductor 104 are positioned within the chamber 140 and placed against the inner surface 136 of the first and second hook portions 130 and 132, respectively. The wedge member 206 is then aligned with the trailing edge 182 of the spring member 220 and the leading end 162 is loaded into the chamber 140 through the trailing edge 182, such as in the direction of arrow B. In an initially loaded position, the conductors 102, 104 are held tightly between the wedge member 206 and the spring member 220 but the spring member 220 remains largely un-deformed. Optionally, the hook portions 130, 132 of the spring member 220 may be partially deflected outward. In an exemplary embodiment, the wedge member 206 is pressed hand-tight within the spring member 220 by the user such that the spring member 220 is minimally deflected.
The wedge member 206 may be loaded in more than one different orientation. In a first orientation, as illustrated in
The final mated position (e.g. the depth of loading) of the wedge member 206 is based on the initial loading orientation of the wedge member 206. The first orientation corresponds to a first final mated position, which is illustrated in
During mating of the wedge member 206 and the spring member 220, an application tool (not shown), such as an adjustable jaw pliers tool, is used to force the wedge member 206 to the final mated position. As the wedge member 206 is pressed into the spring member 220, the hook portions 130, 132 are deflected outward. In one embodiment, the application tool engages a tip portion 226 of the spring member 220 that extends from the leading edge 180 and presses against the trailing end 164 of the wedge member 206 to force the wedge member 206 in the loading direction. As the wedge member 206 is loaded into the spring member 220, the barb 208 or 210 engages the trailing edge 182. The leading ramp surface 212 engages and deflects the web portion 224 of the spring member 220 until the barb 208 or 210 is received within the opening 222. When the barb 208, 210 is received within the opening 222, the wedge member 206 is fully loaded and positioned in the final mated position. As such, the opening 222 may operate as a viewing window for a user to visually verify that the wedge member 206 is fully loaded into the spring member 220. When the rear end 214 of the barb 208 or 210 passes from the web portion 224, the web portion 224 returns to an un-deflected state and operates as a stop to limit removal of the wedge member 206 from the spring member 220. As such, the barb locks the wedge member 206 into position with respect to the spring member 220. When the web portion 224 returns to the un-deflected state, the user may hear an audible snap indicating that the wedge member 206 is fully loaded.
As illustrated in
In the first final mated position, the tap conductor 102 is captured between the channel 118 of the wedge member 206 and the inner surface 136 of the first hook portion 130. Likewise, the main conductor 104 is captured between the channel 120 of the wedge member 206 and the inner surface 136 of the second hook portion 132. As the wedge member 206 is pressed into the chamber 140 of the spring member 220, the hook portions 130, 132 are deflected outward. The spring member 220 is elastically and plastically deflected resulting in a spring back force to provide a clamping force on the conductors 102, 104. The clamping force ensures adequate electrical contact force and connectivity between the connector assembly 100 and the conductors 102, 104. Additionally, elastic deflection of the spring member 220 provides some tolerance for deformation or compressibility of the conductors 102, 104 over time, such as when the conductors 102, 104 deform due to compression forces. Actual clamping forces may be lessened in such a condition, but not to such an amount as to compromise the integrity of the electrical connection.
As illustrated in
In the second final mated position, the tap conductor 102 is captured between the channel 120 of the wedge member 206 and the inner surface 136 of the first hook portion 130. Likewise, the main conductor 104 is captured between the channel 118 of the wedge member 206 and the inner surface 136 of the second hook portion 132. Because the amount of travel of the wedge member 206 is greater when the wedge member 206 is in the second orientation, the portion of the wedge member 206 received within the envelope of the spring member 206 is generally wider. As such, the wedge member 206 may accommodate different, smaller sized conductors 102, 104 when the wedge member 206 is in the second orientation.
In an alternative embodiment, a single barb may extend from the inner surface 136 of the spring member 220, and the wedge member 206 may include a slot on each of the top 114 and the bottom 116 of the wedge member 206. The slots may be offset, such as in similar positions as the positions of the barbs 208, 210 in the above described embodiment. The wedge member 206 may be loaded in a first orientation to a first loaded position, wherein the slot on the top 114 engages the barb extending from the inner surface 136. The wedge member may be loaded in a second orientation to a second loaded position, wherein the slot on the bottom 116 engages the barb.
In another alternative embodiment, both barbs 208, 210 may extend from the same surface, such as the top 114 or the bottom 116. The barbs 208, 210 may be longitudinally spaced along the length of the wedge member 206, such that when the wedge member 206 is loaded to a first depth, the first barb 208 is received within the opening 222, and when the wedge member 206 is loaded to a second depth, the second barb 210 is received within the opening 222. Optionally, a second opening may be provided to receive the first barb 208 when the second barb 210 is received within the opening 222. Optionally, the barbs 208, 210 may be laterally off-set with respect to one another and the two openings may similarly be laterally off-set with one another to receive the corresponding barbs 208, 210. In an alternative embodiment, the opening 222 may be large enough to accommodate both barbs 208, 210, such that the rearward-most barb 208 or 210 that is received within the single opening defines the mated position of the wedge member 206 and locks the mating position of the wedge member 206 with respect to the spring member 220. Alternatively, a single barb may be provided and more than one opening may be provided such that the mating depth is determined by which opening receives the barb.
As described above, the wedge and spring members 106, 108 (or 206, 220) may accommodate a greater range of conductor sizes or gauges in comparison to conventional wedge connectors. Additionally, even if several versions of the wedge and spring members 106, 108 (or 206, 220) are provided for installation to different conductor wire sizes or gauges, the assembly 100 requires a smaller inventory of parts in comparison to conventional wedge connector systems, for example, to accommodate a full range of installations in the field. That is, a relatively small family of connector parts having similarly sized and shaped wedge portions may effectively replace a much larger family of parts known to conventional wedge connector systems. Particularly, because the wedge member 106 (or 206) has two different orientations with respect to the spring member 108 (or 220), a single wedge member 106 (or 206) can effectively replace multiple wedge members used in conventional wedge connector systems.
It is therefore believed that the connector assembly 100 provides the performance of conventional wedge connector systems that does not require a large inventory of parts to meet installation needs. The connector assembly 100 may be provided at low cost, while providing increased repeatability and reliability as the connector assembly 100 is installed and used. The combination wedge action of the wedge and spring members 106, 108 (or 206, 220) provides a reliable and consistent clamping force on the conductors 102 and 104 and is less subject to variability of clamping force when installed than either of known bolt-on or compression-type connector systems.
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means—plus-function format and are not intended to be interpreted based on 35 U.S.C. §112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
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Number | Date | Country | |
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20090061698 A1 | Mar 2009 | US |