Abstract:
A latching mechanism for joining separable insulated connectors employs a plurality of finger contacts to create an interference fit with an electrode probe of an elbow connector. The electrode probe enters a cylindrical grouping of the plurality of finger contacts and a projection causes an interference fit between the finger contacts and the electrode probe. The finger contacts latch the connectors together and require a removal force greater than the latching force required to latch the connectors. The latching mechanism provides a multi-point current path between an elbow connector and a power transmission or distribution apparatus and provides operator feedback to indicate the latching of the mechanism.

Description:
CROSS REFERENCE  
       [0001]     The present application claims the benefit of priority as a continuation in part patent application under 35 U.S.C. §120 to U.S. patent application Ser. No. 11/034,588 entitled “Device and Method for Latching Separable Insulated Connectors” filed on Jan. 13, 2005, which is incorporated by reference in its entirety. 
     
    
     FIELD  
       [0002]     The present application relates generally to the field of separable insulated connectors. More particularly, this application relates to enhancements in latching mechanisms for separable insulated connectors.  
       RELATED ART  
       [0003]     Separable insulated connectors provide the interconnection between energy sources and energy distribution systems. Typically, energy distribution is made possible through a large voltage distribution system, which results in power distribution to homes, businesses, and industrial settings throughout a particular region. In most cases, the distribution of power begins at a power generation facility, such as a power plant. As the power leaves the power plant, it enters a transmission substation to be converted up to extremely high voltages for long-distance transmission, typically in the range of 150 kV to 750 kV. Then power is transmitted over high-voltage transmission lines and is later converted down to distribution voltages (within 2 kV to 10 kV) that will allow the power to be distributed over short distances more economically. The power is then reduced from the distribution voltage, typically around 7,200 volts, and delivered over a distribution bus line to the 240 volts necessary for ordinary residential or commercial electrical service.  
         [0004]     The electrical connectors typically involved in power distribution at the switchgear level, known as separable insulated connectors, typically consist of a male connector and a female connector. The mating of the male and female connectors are necessary to close the electrical circuit, for distribution of power to customers. The female connector is typically a shielding cap or an elbow connector that mates with a male connector. The male connector is generally a loadbreak bushing that typically has a first end adapted for receiving a female connector (e.g., an elbow connector or shielding cap) and a second end adapted for connecting to a bushing well stud. The first end of the male connector is an elongated cylindrical member with a flange on the rim of the member. The flange allows for an interference fit between the bushing and the mating elbow connector. The flange secures the bushing to a groove in the inner wall of the mating elbow connector. The interference fit and the flange-groove mechanism are typical mating methods for a male and female connector.  
         [0005]     Positioned within the male and female connectors are female and male contacts, respectively. The male contact is typically an electrode probe. The female contact is typically a contact tube with a plurality of finger contacts, which mate with the electrode probe from the female connector. When the male and female contacts mate, the electrical circuit is closed.  
         [0006]     The mating of most separable insulated connectors is typically accomplished by an interference-fit rubber latch mechanism to secure an elbow connector with a bushing. Typically, the latch mechanisms of the connectors are lubricated to prevent the connectors from bonding together. To avoid the inadvertent bonding, line-crew operators often over-lubricate the rubber fittings. Typically, these interference-fit latch mechanisms may become unlatched due to over lubrication of the latch ring geometry, which is referred to as the hydraulic effect.  
         [0007]     Many separable insulated connectors provide a visual indicator band, of a contrasting color, for notification that an elbow connector is unlatched from a bushing. However, an elbow connector can subsequently become unlatched after it is connected with the bushing, due to the hydraulic effect between the elbow connector and the bushing. This occurrence can be the result of numerous factors, one factor being the low removal force typically required to unlatch mating connectors.  
         [0008]     Accordingly, it would be advantageous to provide a latching mechanism that exhibits a reduced probability of becoming inadvertently unlatched. Also, it would be advantageous to provide a latching mechanism that requires a force for removing the electrode probe to be greater than the force for latching the electrode probe. Additionally, it would be advantageous to provide a latching mechanism that produces audible notification of latching between the mating separable insulated connectors. It would advantageous to provide a latching mechanism having consistent physical properties over a broad range of temperatures, resulting in more consistent latching performance. Also, it would be advantageous to provide a latching mechanism with an electrode probe having an outside diameter larger than the inside diameter of the finger contacts, resulting in optimal contact pressure and improved current ratings. Lastly, it would be advantageous to provide a latching mechanism having an electrode probe with a first and second recessed area for latching with a plurality of finger contacts. It would be desirable to provide a latching mechanism or the like of a type disclosed in the present application that includes any one or more of these or other advantageous features. It should be appreciated, however, that the teachings herein may also be applied to achieve devices and methods that do not necessarily achieve any of the foregoing advantages but rather achieve different advantages.  
       SUMMARY  
       [0009]     One exemplary embodiment pertains to a latching mechanism for a separable insulated connector. A latching mechanism, in accordance with an exemplary embodiment comprises a cylindrically-shaped electrode probe and a bushing. The electrode probe includes one of either a recessed area or a projection, and the bushing includes a plurality of cylindrically-grouped finger contacts having the alternative one of the recessed area or the projection. The plurality of finger contacts are configured to receive the electrode probe, wherein the electrode probe and the plurality of finger contacts mate by latching the projection into the recessed area.  
         [0010]     In accordance with another exemplary embodiment, a mechanism and method comprise latching an electrode probe with a plurality of finger contacts in a separable insulated connector, wherein, during the latching of the electrode probe and the plurality of finger contacts, the electrode probe enters a cylindrical grouping of the plurality of finger contacts and a projection causes an interference fit between the plurality of finger contacts and the electrode probe.  
         [0011]     In accordance with another exemplary embodiment, a system comprises a high-voltage power transmission or distribution apparatus. The system further comprises an elbow connector, including a first insulated housing and an electrode probe including one of either a recessed area or a projection. The system further comprises a bushing, including a second insulated housing, a conductive layer, and a plurality of finger contacts including the other one of the recessed area or the projection, wherein the finger contacts and the electrode probe mate by latching the projection into the recessed area.  
         [0012]     In accordance with another exemplary embodiment, a method comprises latching an electrode probe of an elbow connector with a plurality of finger contacts in a separable insulated connector, the latching being performed by a projection and a recessed area, wherein the projection latches into the recessed area, providing operator feedback indicating that the separable insulated connector is latched.  
         [0013]     In accordance with another exemplary embodiment, a method comprises latching an electrode probe with a plurality of finger contacts in a separable insulated connector, the electrode probe including one of either a recessed area or a projection and the finger contacts including the other one of the recessed area or the projection, wherein the latching of the electrode probe with the plurality of finger contacts requires an insertion force lower than the force required for unlatching the electrode probe with the plurality of finger contacts.  
         [0014]     Still other advantages of the present invention will become readily apparent to those skilled in this art from review of the enclosed description, wherein the preferred embodiment of the invention is disclosed, simply by way of the best mode contemplated, of carrying out the invention. As it shall be understood, the invention is capable of other and different embodiments, and its several details are capable of modifications in various respects, all without departing from the invention. Accordingly, the figures and description shall be regarded as illustrative in nature, and not as restrictive. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a cross-sectional view of an electrode probe with a recessed middle area and a recessed tip.  
         [0016]      FIG. 2  is cross-sectional view of a cylindrical grouping of finger contacts with a plurality of recessed grooves on the external surface of each finger contact.  
         [0017]      FIG. 3  is an enlarged cross-sectional view of a single finger contact exhibiting a plurality of recessed grooves in the external surface of the finger contact.  
         [0018]      FIG. 4  is a cross-sectional view of a latching mechanism, with an electrode probe mating with finger contacts and the electrode probe riding on the projection of the finger contacts during the latching process.  
         [0019]      FIG. 5  is a cross-sectional view of the latching mechanism, with an electrode probe and finger contacts latched together by the projections being seated in a recessed area of the electrode probe.  
         [0020]      FIG. 6  is a three-dimensional view of a retention spring that can be seated in the recessed grooves of the finger contacts.  
         [0021]      FIG. 7  is a cross-sectional view of an elbow connector with an electrode probe.  
         [0022]      FIG. 8  is a cross-sectional view of a bushing with a grouping of finger contacts for mating with an electrode probe.  
         [0023]      FIG. 9  is a cross-sectional view of an electrode probe with a first and second recessed area and a recessed tip. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]     Referring to  FIG. 1 , electrode probe  1  is illustrated as a cylindrical member with recessed tip  3  near a first end of electrode probe  1 , wherein the cylindrical member may be in the form of a rod or tube. In a circuit closing operation, recessed tip  3  is the first section of electrode probe  1  to connect with finger contacts  11  (shown in  FIGS. 2 and 3 ). Recessed tip  3  is contoured to penetrate into the grouping of finger contacts  11  (shown in  FIG. 5 ). Electrode probe  1  also has recessed area  5  near the middle of the cylindrical body of electrode probe  1 . Recessed area  5  provides a contact point for interlocking electrode probe  1  with finger contacts  11  (shown in  FIG. 5 ).  
         [0025]     Threaded base  7  is positioned at a second end of the cylindrical body of electrode probe  1 , opposite recessed tip  3  of electrode probe  1 . Threaded base  7  is recessed from the general radius of electrode probe  1 , and threaded base  7  provides electrode probe  1  with a connection to the power cable of an elbow connector.  
         [0026]     In one embodiment, electrode probe  1  and finger contacts  11  may comprise metal or a similar conductive material. In another embodiment, electrode probe and finger contacts  11  preferably comprise a conductive material having consistent physical properties, wherein the conductive material is less affected by varying temperatures and will provide consistent performance in a broad range of temperatures.  
         [0027]     Referring now to  FIG. 2 , a plurality of finger contacts  11  is illustrated as a cylindrical grouping for mating with electrode probe  1 . Each finger contact  11  has a projection  13  near a first end of each finger contact  11 . Projection  13  is a protrusion on the inner surface of each finger contact  11  that provides a contact point for each finger contact  11  to interlock with recessed area  5  of electrode probe  1  when fully latched together. As electrode probe  1  is inserted into a plurality of finger contacts  11  during a loadbreak operation, electrode probe  1  slides into the grouping of finger contacts  11  by riding on projection  13  of each finger contact  11  (shown in  FIG. 4 ). Projection  13  provides a reduced surface area over which electrode probe  1  must traverse in order to make full connection with the plurality of finger contacts  11 .  
         [0028]      FIGS. 2 and 3  also illustrate a plurality of recessed grooves  19  on the external surface of each finger contact  11 . Each recessed groove  19  is an indentation formed in the external surface of each finger contact  11 . Each recessed groove  19  can house an expandable retention spring (shown in  FIGS. 4, 5 , and  6 ), for restricting the flexibility of finger contacts  11 .  FIG. 3  provides an enlarged illustration of recessed grooves  19  and projections  13  on a single finger contact  11 .  FIG. 2  also illustrates threaded base  17  positioned at the second end of finger contacts  11 , opposite the plurality of projections  13  on finger contacts  11 . Threaded base  17  is recessed from the general radius of the body of finger contacts  11 , and threaded base  17  provides finger contacts  11  with a connection to bushing well stud of a switchgear.  
         [0029]      FIGS. 4 and 5  illustrate the penetrating and latching of electrode probe  1  into finger contacts  11 . As shown in  FIG. 4 , electrode probe  1  penetrates into the plurality of finger contacts  11  and slides into the central common area of finger contacts  11  by riding on the plurality of projections  13 . The plurality of projections  13  allows electrode probe  1  to slide into finger contacts  11 , requiring a reduced amount of force and friction for inserting electrode probe  1  into finger contacts  11 . In one embodiment, each projection  13  may be formed with a rounded face and a backside comprising a ridge angled steeper than the rounded face on the front-side of projection  13 . The ridge of projection  13  is sloped closer to perpendicular to the axis of motion of electrode probe  1  than the rounded face of projection  13 . The rounded face of projection  13  allows electrode probe  1  to slide into the plurality of finger contacts  11  with minimal resistance and reduced friction. As recessed tip  3  of electrode probe  1  converges with the rounded face of projection  13 , recessed tip  3  glides into finger contacts  11  due to the minimal friction with the rounded face of projection  13 . Conversely, the backside of projection  13  comprises a ridge for latching electrode probe  1  into finger contacts  11 . Upon seating of electrode probe  1  within finger contacts  11 , the ridge of projection  13  locks into recessed area  5 . The ridge of projection  13  comprises a steeper angle than the rounded face on the front-side of projection  13 , which results in requiring a greater removal force for electrode probe  1  from the plurality of finger contacts  11  than the required insertion force. The plurality of projections  13  allows the force required for latching a connector to be lower than the force required to unlatch the same connector.  
         [0030]     In another embodiment, the angle of the front-side and backside of projection  13  may be configured to accomplish latching and unlatching of the separable insulated connectors with varying levels of force. The angle of projection  13  and recessed area  5  may be configured such that upon applying a requisite force to separate electrode probe  1  from finger contacts  11 , the force would be sufficient to remove electrode probe  1  and preferably reduces the likelihood of arcing resulting from slowly separating electrode probe  1  and finger contacts  11 . Additionally, in yet another embodiment, the angle and configuration of recessed tip  3  and projections  13  may be adjusted to accomplish latching the separable insulated connectors with varying levels of force. The configuration of recessed tip  3  may be adjusted such that upon applying a requisite force to insert electrode probe  1  into the common area of the plurality of finger contacts  11 , there is sufficient force to slide electrode probe  1  into a fully latched position in finger contacts  11 . Such an embodiment preferably reduces the likelihood of experiencing line to ground faults or connector back-offs. In another embodiment, the separable insulated connector may be configured to aid-in or facilitate a fault closure. During a fault close operation, the latching mechanism of electrode probe  1  and finger contacts  11  can prevent electrode probe  1  from springing out of the closed position. Such an embodiment enables the latching mechanism to properly engage during a high-current operation, thereby improving the likelihood of a successful fault closure.  
         [0031]     When electrode probe  1  is inserted into finger contacts  11 , the grouping of finger contacts  11  expands outwardly due to the springiness of each finger contact  11 . In order to increase the contact pressure of each finger contact  11 , recessed grooves  19  on the external surface of each finger contact  11  house retention springs  15 .  FIG. 6  illustrates a retention spring  15  as a flexible, circular member, capable of expanding or contracting based on the applied force. Referring back to  FIG. 4 , as finger contacts  11  expand outwardly, retention spring  15  preferably limits the resilience of each finger contact  11 , thus making the structure more rigid.  
         [0032]     In one embodiment, optimal contact pressure may be achieved by providing electrode probe  1  with an outside diameter greater that the inside diameter of the current carrying area of the grouping of finger contacts  11 . Preferably, the current carrying area of finger contacts  11  includes the central common area of finger contacts  11  including the elongated portion shown in  FIGS. 2, 4 , and  5 . In such a case, recessed tip  3  is preferably configured to wedge finger contacts  11  outward. Retention spring  15  may be positioned on the external surface of finger contacts  11 . Finger contacts  11  may be configured to serve as a moment arm thereby increasing the compression force of retention spring  15  on recessed tip  3  of electrode probe  1 . The compression force creates an optimal contact pressure with electrode probe  1 , thereby generating improved current ratings for the system.  
         [0033]     Also, as shown in  FIG. 4 , electrode probe  1  touches each finger contact  11  primarily just on the surface of each projection  13 , until each projection  13  reaches recessed area  5  of electrode probe  1 . When each projection  13  is seated in recessed area  5  of electrode probe  1 , electrode probe  1  is fully latched into the plurality of finger contacts  11 . The mating of the electrode probe  1  and the plurality of finger contacts  11  produces an audible sound to denote latching of the mating interfaces. As electrode probe  1  rides on the surface of projection  13 , finger contacts  11  are expanded outwardly due to the springiness of each finger contact  11 . When the plurality of projections  13  reach recessed area  5 , finger contacts  11  immediately contract from their expanded position. The contraction of finger contacts  11  snaps projections  13  into recessed area  5 , thus creating an audible sound indicating that projections  13  are seated in recessed area  5 . Electrode probe  1  is latched into finger contacts  11  when recessed area  5  and projections  13  make contact and are interlocked, as illustrated in  FIG. 5 . The audible sound may be an audible click, ring, or any audible notification loud enough to be heard by the unaided ear from a distance of at least four (4) feet to ten (10) feet, in order to audibly indicate latching of the interfaces to a lineman using a live-line tool.  
         [0034]     Referring to  FIG. 7 , elbow connector  21  is illustrated with electrode probe  1 . Elbow connector  21  is housed in external insulated housing  23  and has an axial bore therethrough providing a hollow center for mating with bushing  31  (shown in  FIG. 8 ). Insulated housing  33  is typically composed of a rubber compound; however, the housing is capable of other compositions. Insulated housing  33  provides a durable protective covering for electrode probe  1 . Electrode probe  1  is positioned within elbow connector  21  and is secured in place by threaded base  7 . Threaded base  7  provides electrode probe  1  with a connection to power cable  25  of elbow connector  21 .  FIG. 7  also illustrates recessed area  5  and recessed tip  3  (also shown in  FIG. 1 ). Recessed tip  3  is curved in order to penetrate into a grouping of finger contacts  11 , and recessed area  5  provides a contact point for latching electrode probe  1  with finger contacts  11  and also for conducting current between elbow connector  21  and a bushing well stud.  
         [0035]     Referring to  FIG. 8 , bushing  31  is illustrated with a plurality of finger contacts positioned within. Bushing  31  is housed in insulated housing  33 . Insulated housing  33  is also typically composed of a rubber compound; however, the housing is also capable of other compositions. Insulated housing  33  has a first and second end. The first end is an elongated cylindrical member for mating with elbow connector  21  and the second end is adapted for connecting to a bushing well stud.  
         [0036]     The middle section of insulated housing  33 , typically referred to as semi-conductive shield  35 , is positioned between the first end and second end. The middle section is preferably comprised of a semi-conductive material that provides a deadfront safety shield. Positioned within the bore of insulated housing  33  is an internal conductive layer  37  layered close to the inner wall of insulated housing  33 . Internal conductive layer  37  preferably extends from near both ends of insulated housing  33  to facilitate optimal current flow. Positioned within internal conductive layer  37  is internal insulative layer  39 , which provides insulative protection to conductive layer  37 .  
         [0037]     Further positioned within the axial bore of bushing  31  are a plurality of finger contacts  11 . Finger contacts  11  provide a multi-point current path between electrode probe  1  (shown in  FIGS. 1, 4 ,  5 , and  7 ) and a bushing well stud. When elbow connector  21  is mated with a bushing  31 , electrode probe  1  enters into bushing  31 , to connect with finger contacts  11  for continuous current flow. As shown in  FIGS. 2, 3 , and  4 , each finger contact  11  has a projection  13  that allows electrode probe  1  to rest on while sliding into the central common area of finger contacts  11 . Once electrode probe  1  has become completely seated within finger contacts  11 , each projection  13  latches into recessed area  5  of electrode probe  1  (shown in  FIG. 5 ). Also, threaded base  17  is positioned at the end of finger contacts  11 , opposite projections  13 . Threaded base  17  is recessed from the general radius of the body of finger contacts  11  and provides finger contacts  11  with a secure connection for current conductance to bushing  31 .  
         [0038]     In another embodiment, electrode probe  1  may be configured as a cylindrical member with a first and second recessed area ( 5 ,  6 ) for receiving projections  13  of finger contacts  11 . Referring to  FIG. 9 , electrode probe  1  is illustrated as a cylindrical member with recessed tip  3  near a first end of electrode probe  1 , wherein the cylindrical member may be in the form of a rod or tube. Recessed tip  3  is contoured to penetrate into the grouping of finger contacts  11 . Electrode probe  1  also has a first recessed area  5  near the middle of the cylindrical body of electrode probe  1 . First recessed area  5  provides a contact point for interlocking electrode probe  1  with finger contacts  11 . Second recessed area  6  is positioned between first recessed area  5  and recessed tip  3 . Second recessed area  6  provides an additional contact point for electrode probe  1 . Particularly, second recessed area  6  may serve as a contact point when the separable insulated connectors may need to be manually separated. In some cases, the separable insulated connectors may need to be pried, forced apart, or slowly separated from each other due to bonding resulting from the effects of varying temperature, lubricant bonding, equipment aging/wear, etc. In such cases, the projections of finger contacts  11  may become seated in second recessed area  6  while the connectors are being separated and still carrying current. By providing second recessed area  6 , the connectors may be separated from a bonded state while still passing current and therefore supplying power to utility customers. With projections  13  being positioned in second recessed area  6 , the separable insulated connectors can be separated more easily without resulting in teasing of the contacts of the connectors and thereby reducing the likelihood of arcing. In such an embodiment, by positioning projections  13  in second recessed area  6 , sufficient force must be employed to remove projections  13 . The amount of force required to overcome the latching mechanism and remove projections  13  from second recessed area  6  will exceed the minimal force necessary to tease the contacts and will potentially minimize the occurrence of that condition.  
         [0039]     Throughout the specification, numerous advantages of exemplary embodiments have been identified. It will be understood of course that it is possible to employ the teachings herein so as to without necessarily achieving the same advantages. Additionally, although many features have been described in the context of a power distribution system comprising multiple cables and connectors linked together, it will be appreciated that such features could also be implemented in the context of other hardware configurations. Further, although certain methods are described as a series of steps which are performed sequentially, the steps generally need not be performed in any particular order. Additionally, some steps shown may be performed repetitively with particular ones of the steps being performed more frequently than others, when applicable. Alternatively, it may be desirable in some situations to perform steps in a different order than described.  
         [0040]     Many other changes and modifications may be made to the present invention without departing from the spirit thereof.