BACKGROUND
The present invention relates generally to the field of separable insulated connectors. More particularly, this invention relates to enhancements in latching mechanisms for separable insulated connectors.
RELATED ART
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 that will allow the power to be distributed over short distances more economically. The power is then reduced from the 7,200 volts, typically delivered over a distribution bus line to the 240 volts necessary for ordinary residential or commercial electrical service.
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.
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.
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.
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.
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 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
One exemplary embodiment pertains to a latching mechanism for a separable insulated connector. A latching mechanism, in accordance with an exemplary embodiment comprises an electrode probe and a plurality of finger contacts. The electrode probe includes one of either a recessed area or a projection, and a plurality of finger contacts includes the alternative one of the recessed area or the projection. The finger contacts and the electrode probe mate by latching the projection or projections into the recessed area.
In accordance with another exemplary embodiment, a mechanism and method comprise latching an electrode probe with a plurality of finger contacts, wherein the tip of the electrode probe penetrates into a cylindrical grouping of finger contacts. A projection in the latching mechanism causes an interference fit between the finger contacts and the electrode probe.
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
FIG. 1 is a cross-sectional view of an electrode probe with a recessed middle area and a recessed tip.
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.
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.
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.
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.
FIG. 6 is a three-dimensional view of a retention spring that can be seated in the recessed grooves of the finger contacts.
FIG. 7 is a cross-sectional view of an elbow connector with an electrode probe.
FIG. 8 is a cross-sectional view of a bushing with a grouping of finger contacts for mating with an electrode probe.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
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).
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.
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.
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.
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. Each projection 13 is 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.
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 limits the resilience of each finger contact 11, thus making the structure more rigid.
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, in order to indicate latching of the interfaces.
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.
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.
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.
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.
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.
Many other changes and modifications may be made to the present invention without departing from the spirit thereof.
Patent Application
20060154507
