Visual latching indicator arrangement for an electrical bushing and terminator

An elbow terminator has a socket in which an electrical probe is disposed. The terminator is insertable onto an electrical bushing such that a tongue of the bushing is received in the socket of the terminator, and the probe of the terminator is electrically coupled to a contact sleeve disposed within the tongue. A latching mechanism produces positive latching between the tongue and socket when the tongue has been inserted to a predescribed depth within the socket. In order to enable an operator to visually observe that the tongue has been inserted to the prescribed depth, the bushing carries a color band which becomes completely disposed (invisible) in the socket when positive latching occurs. Alternatively, the bushing can be provided with gauge tabs which become aligned with a witness line formed on the terminator when positive latching occurs.

BACKGROUND OF THE INVENTION

The present invention relates to the interconnection of electrical distribution elements and, in particular, to the interconnection between a loadbreak elbow terminator and a bushing.

Electrical distribution equipment, such as a deadfront switch gear arrangement, typically includes fixed electrical bushings which are to be connected to external electrical cables. The fixed bushings are mounted in a wall of the electrical equipment and have their outer ends arranged to be connected to the cables.

One way of achieving this connection is by inserting an elbow terminator onto the bushing, the terminator being coupled to the cable. The elbow terminator, which typically comprises a tapered socket in which an electrical probe is mounted, is intended to be inserted onto the fixed bushing such that a tapered tongue of the bushing enters the socket. In so doing, a conductive tube disposed within the tongue makes electrical connection with the probe, thereby connecting the cable to the fixed bushing.

The elbow terminator is secured to the bushing by means of a latching ring disposed at an inner end of the socket. That latching ring snaps into an annular latching groove formed in the outer periphery of the leading end of the tongue when the elbow terminator is pushed onto the fixed bushing.

The elbow terminator is maneuvered onto the bushing by means of a hand-held shotgun stick which grabs a hook eye affixed to the elbow terminator. It may occur, however, that the tongue does not completely enter the socket, whereby the latching ring does not tightly grip the latching socket. That unlatched condition, which is potentially dangerous, is difficult for the operator to visually detect, especially since the operator will likely be standing remotely (e.g., at least three to five feet) from the terminator and bushing, for safety reasons.

It would therefore be desirable to facilitate the ability of the operator to detect an unlatched condition, especially when standing remotely of the terminator and bushing.

SUMMARY OF THE INVENTION

The present invention relates to the combination of an electrical terminator and an electrical bushing component. The terminator includes a socket, and the bushing component includes a tongue receivable in the socket to electrically interconnect the terminator and bushing. The tongue and socket include a latching arrangement for positively latching the bushing component and terminator together when the tongue enters the socket to a prescribed depth. First and second visual indicators are disposed on outer peripheries of the bushing component and the terminator, respectively. The first and second visual indicators are arranged so that when the terminator is longitudinally inserted onto the bushing, the first and second indicators longitudinally approach one another sufficiently to at least become radially aligned with one another in order to provide a visual indication of positive latching. One of the first and second indicators is situated radially outside of the other of the indicator and is visible when the combination is viewed in a radially inward direction passing through the one indicator.

In another aspect of the invention, an indicator is defined by a color band formed on one of the terminator and bushing component (preferably on the bushing component) and is arranged to be radially covered by an indicator in the form of a covering portion of the other of the terminator and bushing component (preferably the terminator) when the tongue enters the socket to the prescribed depth, thereby providing a visual indication of positive latching.

The present invention also relates to an electrical bushing component which possesses the color band, and also to a method of connecting an electrical terminator to an electrical bushing component which involves causing the color band to be covered when positive latching occurs.

Depicted inFIG. 1is a loadbreak elbow terminator10and a bushing12adapted for connection therewith. The bushing can be of a type which is fixed to a stationary panel such that a tongue22is externally exposed. The elbow terminator includes a socket14formed in an electrical insulative material16. The socket14includes a tapered portion13and merges into a cylindrical portion15. Extending centrally along the socket is a probe18which carries an arc follower20. The probe18is electrically connected to a cable19.

The tongue22is configured to make an interference fit within the socket14. Adjoining the tongue22is a cylindrical enlargement24configured to enter the cylindrical portion15. The tongue22is hollow and includes a contact tube26(seeFIG. 3) in which are disposed an arc interrupter28and a contact sleeve30.

An end of the tongue22includes a latching groove32. When the elbow terminator is pushed onto the bushing12, the latching groove32receives, by snap fit, a latching ring34formed on a semiconducting insert35at an inner end of the socket14. In that fashion, the bushing becomes secured to the elbow terminator.

As thus far described, the elbow terminator10and bushing12are conventional. The elbow terminator is maneuvered onto the bushing12by a conventional shotgun stick (not shown) which is manipulated manually by an operator. The shotgun stick includes a hook which grips a hook eye38carried by the elbow terminator. As explained earlier, it may occur that the tongue does not fully enter the socket, so that the latching ring34does not completely enter the latching groove32. In that event, the bushing could become dislodged from the elbow terminator10.

That problem is avoided by the present invention which involves the addition of a visual indicating arrangement which visually indicates when the tongue has entered the socket to a sufficient longitudinal depth to ensure latching. The visual indicating arrangement comprises cooperative visual indicators positioned on the busing and elbow terminator such that the locations of the visual indicators relative to one another in the longitudinal direction is readily visible to the operator. When the visual indicators attain a certain longitudinal relationship, it is ensured that positive latching has occurred. The edge56is visible when the bushing12is viewed in a radially inward direction D passing through the edge56, as is evident fromFIGS. 3 and 4.

The visual indicators comprise an indicator gauge40disposed exteriorly on the bushing12, and an indicator ring42disposed exteriorly on the elbow terminator10. The indicator ring42encircles the outer periphery of the elbow terminal at the entrance to the cylindrical portion15and forms a shoulder44which defines a mark in the form of an annular edge indicator or witness line46.

The indicator gauge40includes an annular base portion48which encircles the outer periphery of the busing at a location remote from the leading end thereof, i.e., remote from the latching groove32for the preferred version.

Projecting radially inwardly from an inner diameter of the base portion48is an annular ridge50configured to snap into a corresponding annular depression formed in the bushing. The semiconductive ground shield52could be modified to provide an appropriate surface in which the annular depression can be formed. Alternatively, the semiconductive ground shield52could be modified to include the spaced tabs54as an integral, i.e., one-piece, part.

Projecting longitudinally from the base48is a plurality of circumferentially spaced tabs54. Each tab54includes a beveled free end55which defines a mark in the form of a circumferentially extending indicator edge56at a radially inner portion of that free end55. The tabs54are of a prescribed length so that when the tongue22enters the socket14to a longitudinal depth sufficient to ensure positive latching by the latching ring34and latching groove32, the indicator edges46,56will either be radially aligned with one another (as shown inFIG. 4) or pass one another (i.e., the indicator edges56would be disposed to the left of the indicator edge46inFIG. 4). Thus, an operator can tell, merely by a visual inspection of the relative longitudinal locations of the edges56,46whether positive latching has occurred.

The beveling of the free ends5S of the tabs makes it easier for the operator to observe the indicator edges56. By forming the tabs54on an annular base48, the tabs can be conveniently mounted as a unit on the bushing. It will be understood by those skilled in the art that, depending upon the configuration of the outer periphery of the bushing, it may be possible to mold the bushing with tabs in lieu of providing a snap-on base48to which the tabs are mounted.

It may also be desirable to reverse the parts, i.e., to provide the gauge tabs54on the terminator and provide the indicator ring42on the bushing.

The indicator ring42could comprise an integral, one-piece portion of the terminator housing, or a separately attached piece.

It may be desirable to color the gauge tabs54differently from the indicator ring42in order to contrast the edges46,56as much as possible and thereby, facilitate a proper observation by the operator.

While in the disclosed preferred embodiment the indicator gauge40is disposed on a bushing, it will be appreciated that the indicator gauge could also be disposed on a bushing insert which is to be mounted to a bushing. Bushings (such as, for example, LBC devices, standoffs, and one-piece bushings) and bushing inserts can be generically referred to as “bushing components”.

A second embodiment of the invention, depicted inFIGS. 5 and 6, involves a loadbreak elbow terminator100and a bushing112, wherein a visual indicator or mark114is provided on the bushing to cooperate with a visual indicator116provided on the terminator.

The visual indicator116on the terminator is defined by an end portion or end flange of the terminator which surrounds the cylindrical portion115of the terminator socket into which a tongue118of the bushing is to be inserted.

The visual indicator114on the bushing is in the form of an annular color band of width W formed directly on the outer surface of the tongue118of the bushing. The color of the band114sharply contrasts with that of an adjacent portion120of the tongue118and also with that of the outer surface of the flange116. Preferably, the band color is of a highly visible nature, such as a bright dayglow color like yellow, orange, lime green, etc., which is readily visible from at least a three to five foot distance. The color of an adjacent portion of the tongue would be formed of a contrastingly dark color such as brown or gray.

The band114forms an edge indicator or witness line122at its junction with the adjacent portion120of the tongue. Likewise, the end flange116of the terminator defines an edge indicator124.

The relationship between the edge indicators122,124is such that when the terminator is longitudinally inserted onto the bushing sufficiently far for positive latching to occur in the manner described earlier herein, the edge indicators122,124will have longitudinally approached one another sufficiently to be at least radially aligned with one anther. That is, when positive latching has occurred, the color band114will be completely disposed within the socket portion115and no longer visible.

That indication will be discernable by an operator who views the bushing in a radial direction (i.e., radially with reference to the longitudinal axis thereof), from a distance of at least three to five feet. This enables the operator to maintain a safety distance while determining that latching has occurred.

The color band114can be applied in any suitable manner, preferably by applying a colored ink by means of a roller traveling around the outer periphery of the tongue. The band114is preferably circumferentially continuous, but it could be interrupted as well, since it is only required that the band be at least partly visible when there is no positive latching, and be invisible when there is positive latching.

The radial distance between the color band114and the longitudinal center axis of the tongue is larger than the radial distance between the axis and all portions of the outer circumferential surface of the tongue118situated between the color band and a free end130of the tongue, as is clear fromFIG. 5. As a result, the color band can easily be viewed by an operator who is located to the left of the bushing112inFIG. 5while applying the terminator. In particular, the outer circumferential surface of the tongue118includes a first portion131extending from the free end130, and a second portion132disposed radially outwardly of the first portion and separated from the first portion by a radial wall134of the tongue which is oriented perpendicular to the center axis of the tongue. The color band114is disposed flush on the second portion.