US3238291A

US3238291A - Terminal cover

Info

Publication number: US3238291A
Application number: US445418A
Authority: US
Inventors: Clarence A Bosch; Jr James I Metzger
Original assignee: Wagner Electric Corp
Current assignee: McGraw Edison Co
Priority date: 1965-04-05
Filing date: 1965-04-05
Publication date: 1966-03-01
Anticipated expiration: 1983-03-01

Description

March 1, 1966 c. A. BOSCH ETAL 3,238,291

TERMINAL COVER Filed April 5, 1965 2 Sheets-Sheet 1 I4 1 l I 2 l l I4 I0 9 43 2| 3 g 45 18 1| I '7 i =1 8 r 4 I9 I 6 H I0 2 E? :3 I I I 4 I L g 24 I 224 L In] C 1 I I FIG. 2 l I L I I lNVENTORS m 11]] JAMES I. METZGER JR.

' CLARENCE A. BOSCH FIG "1 WQM TERMINAL COVER Filed April 5, 1965 2 Sheets-Sheet 2 35 I INVENTORS u JAMES l- METZGER JR- 47 47 47 CLARENCE A- BOSCH United States Patent 3,238,291 TERMINAL COVER Clarence A. Bosch, Ferguson, and James I. Metzger, Jr., St. Louis County, Mo., assignors to Wagner Electric Corporation, St. Louis, Mo., a corporation of Delaware Filed Apr. 5, 1965, Ser. No. 445,418 4 Claims. (Cl. 174-138) This invention relates to bushings mounted on electrical apparatus and most particularly to a cover for the terminal assembly end of the bushing.

It is well known in the electrical industry that a short circuit may be formed in an electrical apparatus, such as a distribution transformer, by animals simultaneously contacting the lid of the transformer and the terminal assembly connected to the bushing. It has been found desirable in an attempt to minimize the possibility of animals causing these short circuits to provide an electrical non-conductive cover on the terminal assembly end of the bushing. Some of these prior art terminal covers have used additional members assembled to the main body of the terminal cover to insure proper location and secure fit over the terminal assembly thereby requiring ,assemblance of the terminal cover before it can be placed over the terminal assembly. Other prior art terminal covers lack locking or form-fitting features so that the terminal cover can turn about the terminal assembly resulting in the misalignment of the arrestor gap hole with respect to the arrestor spark gap formed between the terminal assembly and the lightning arrestor. Still other of these prior art terminal covers have been secured to the terminal assembly end of the bushing by snapping over the top petticoat which has the undesirable feature of diminishing the creep and flashover distances of the bushing and of requiring a large configuration terminal coverto fit over the top petticoat. Also, some of the terminal covers are taped onto the bushing to prevent dislocation and rotation of the terminal cover relative to the terminal assembly thereby establishing the undesirable feature of making it possible for water to be trapped within the area above the top petticoat.

It is therefore a general object of this invention to provide .a novel terminal cover which substantially encloses the terminal assembly and which overcomes the aforementioned disadvantages.

Another object is to provide a one piece terminal cover which is economically manufactured and is simply assembled to the terminal end of the bushing. 1

Another object is to provide a terminal cover which locks onto the terminal assembly by snapping over the bottom flange of the terminal assembly.

A further object is to provide a one piece terminal cover having a pre-formed shape approximately the shape of the terminal assembly which provides maximum enclosure of the terminal assembly.

A further object is to provide a terminal cover which completely encloses the terminal assembly except for the lightning arrestor gap hole and which, due to the formfitting feature of the terminal cover, insures proper positioning and prevents dislocation thereby providing for the proper alignment of the arrestor gap hole with'respect to the terminal assembly.

Still another object is to provide a novel terminal cover having an extended conical section severable to form an aperture with a diameter complementary to the diameter of the power line which passes through the terminal cover 1 to be connected with the terminal assembly.

Still another object is to provide an improved terminal cover having means for draining water therefrom which may enter the terminal cover.

These and other objects and advantages will become apparent hereinafter.

"ice

Briefly, in accordance with one aspect of the present invention, a terminal cover for substantially enclosing an electrical terminal is provided with lip means for grip ping engagement with the terminal for removably securing the cover to the terminal. In accordance with another aspect of the invention, a terminal cover for substantially enclosing an electrical terminal having an electrode for a spark gap is provided with aperture means for the spark gap and abutment means engageable with a portion of the terminal to predeterminately maintain alignment between the aperture and electrode.

In the drawings which illustrate an embodiment of the invention,

FIG. 1 is a sectional view of a terminal cover in accordance with the present invention positioned over a terminal assembly,

FIG. 2 is another sectional view of the terminal cover taken along the line 2-2 of FIG. 1,

FIG. 3 is a sectional view of the terminal cover of FIG. 1 but in its manufactured state,

FIG. 4 is another sectional view of the terminal cover taken along the line 44 of FIG. 3, and

FIG. 5 is another sectional view of the terminal cover taken along the line 55 of FIG. 4. 1

Referring now to FIGS. 1 and 2, a conventional bushing 1 is mounted on the cover of an electrical device, such as a distribution transformer (not shown), and a terminal assembly of standard construction, indicated generally at 2, is provided with a cast body portion 3 having an annular flange mounting base 4 which is threadedly received and abuttingly engages the top of said bushing. An arm portion 5 integrally connected to the cast body portion 3 acts as an electrode for a spark gap from a lightning arrestor (not shown), and an aperture 6 provided through said cast body portion has an axis 7 perpendicular to said arm portion. An eye bolt member 8 includes a threaded portion 9 extending through the aperture 6 having a nut 10 threadedly received thereon, and a spring member 11 is positioned between said nut and the cast body portion 3 about said threaded portion. A power line 12 is clamped between the eye bolt member 8 and the cast body portion 3 due to movement of said eye bolt member toward said cast body portion as the nut 10 is rotated on the extending threaded portion 9 in a direction compressing spring member 11 against said cast body portionc A terminal cover 13 is positioned over the terminal assembly 2 and at the upper extremity of said terminal cover is provided an aperture 14 through which the power line 12 passes to be connected with said terminal assembly.

Referring now to FIGS. 3, 4 and 5, the terminal cover 13 consists of an electrically nonconducting material having a pre-formed shape which includes a beveled base portion 15 and a constant diameter main body portion 16 having

projections

17, 18 and protuberance 19 incorporated therein to approximate the configuration of the terminal assembly 2. An extended conical portion 20 is integrally connected to the main body portion 16 at a tapering neck portion 21 and therefrom progressively decreases in diameter to a closed tip 22. Calibrated markings may be provided along the length of the conical portion 20 for indicating the proper point of severance of said conical portion to form the aperture 14 with a diameter corresponding to the diameter of the power line 12. The main body portion 16 has an interior diameter 23 which will accommodate the annular flange mounting base 4 of the terminal assembly 2 when the terminal cover 13 encloses said terminal assembly. A lip 24, provided in the interior of the terminal cover 13 at the intersection of the body portion 16 and the beveled base portion 15, defines another interior diameter 25 substantially smaller than the interior diameter 23 with said lip being yieldable to thereby permit the interior diameter 23 to receive the annular flange mounting base 4.

As shown by the embodiments of the present invention in FIGS. 1 and 2, the aperture 14 formed in the conical portion 20 for receiving the power line 12 is substantially aligned with respect to the terminal assembly 2. This alignment may be accomplished, as shown in FIG. 3, by having the conical portion 20 eccentrically positioned with respect to a central axis 26 of the main body portion 16 at a circumferentially predetermined location from the projection 17, or depending upon the type of terminal assembly to be enclosed, this alignment may be accomplished by having said conical portion axially aligned with said central axis.

Referring again to FIGS. 3, 4 and 5, the projection 17 is provided in the periphery of the main body portion 16 for covering the extended threaded portion 9 and the nut 10 of the terminal assembly 2. The exterior of the projection 17 provides an extended oblong portion 27 which obliquely rises from the beveled base portion to a predetermined point 28 from the central axis 26 and therefrom acutely recedes until said oblong portion is incorporated in the periphery of the main body portion 16. Stepped

grooves

29 and 30 are provided in the interior of the oblong portion 27 intersecting the beveled base portion 15 and extending to an upper interior wall 31 defined by said oblong portion. The narrower groove 29 is provided to receive the extended threaded portion 9 and follows the oblique configuration of the oblong portion 27 so that a bottom 32 of said narrow groove is further away from the central axis 26 at the upper interior wall 31 than at the intersection of said narrow groove with the beveled base portion 15. The broader groove 30 is centered with respect to the groove 29 and is provided in the interior of the oblong section 27 for receiving the nut 10 on the threaded portion 9. A bottom 33 for the broader groove 30 is formed at the intersection of the

stepped grooves

29, 30 with said bottom, from the upper interior wall 31 to the intersection of said broader groove with the beveled base portion 15, maintaining a constant distance 34 from the central axis 26.

The protuberance 19 for enclosing the eye bolt member 8 is circumferentially predeterminately located from the projection 17 and is provided on the terminal cover 13 to permit a variable amount of extension of said eye bolt member from the cast body portion 3 in the clamping of a variable diameter power line in the manner hereinabove described and as illustrated in FIG. 2 using the power line 12.

Projection 18 is predeterminately circumferentially located with respect to projection 17, and is incorporated in the periphery of the main body portion 16 for enclosing the arm portion 5 of the cast body portion 3. The exterior of projection 18 consists of a rectangular raised portion 35 which has one end intersecting the beveled base portion 15 and the other end thereof intersecting a protruded section 36 which extends from the periphery of the main body portion 16 to a greater degree than does said rectangular raised portion. A groove 37 having a base wall 38 at a constant distance 39 from the central axis 26 is provided in the interior of the projection 18 and corresponds to the rectangular raised portion 35. A recessed cavity 40 is provided in the interior of protruded section 36 having a cavity wall 41 at a distance 42 from the central axis 26, and said distance 42 is greater than the distance 39 to the base wall 38 of the groove 37. The groove 37 has one end intersecting the beveled base portion 15 and the other end thereof intersects the cavity 40. An aperture 43 is provided through the terminal cover 13 in the protruded section 36 with said aperture being located at a predetermined distance 44 from the lip 24 and said predetermined distance corresponds and is equal to a distance 45 between the bottom of annular flange mounting base 4 and the arm portion 5. Therefore, when the terminal cover 13 is properly positioned over the terminal assembly 2, the arm portion 5 is substantially aligned with the aperture 43.

The interior wall of the main body portion 16 is provided with indentations 46, and the beveled base portion 15 is provided with rib sections 47 which for clarity and understanding were not shown in FIGS. 1 and 2 but are hereinafter described. The indentations 46 extend through the lip 24 to establish a drain path from the interior of the terminal cover 13 past said lip, when said l=ip is grippingly engaged with the flange mounting base 4 of the terminal assembly 2, for the drainage of water which may enter said terminal cover through the

apertures

14 and 43. Rib sections 47 are provided on the interior of the beveled base portion 15 adjacent to the

stepped grooves

29, 30 of projection 17, the groove 37 of projection 18 and the indentations 46 for abutting engagement with the bushing 1 adjacent the terminal assembly 2. The rib sections 47 establish clearance between the bushing 1 and the beveled base portion 15 so that water which enters the terminal cover 13 may drain through the groove 37, stepped

grooves

29, 30 and the indentations 46 and therefrom past said beveled base portion due to the clearance between said bushing and said beveled base portion. The indentations 46 also allow for extra expansion of the terminal cover '13 when being placed over the terminal assembly 2.

In the use of the terminal cover 13, the extended conical portion 20 is severed to form an aperture 14 having a diameter complementary to the diameter of the power line 12. The power line 12 is then inserted through the aperture 14 and the terminal cover 13 is slipped along said power line to .a position away from the terminal assembly 2, as illustrated in FIGS. 1 and 2 and with said terminal cover in this position, said power line may be connected with said terminal assembly. After the power line 12 is connected with the terminal assembly 2, the terminal cover 13 is positioned so that projection 17 is aligned with the threaded portion 9 and the bolt 10 which, due to the pre-formed shape of said terminal cover, will predeterminately align projection 18 with the arm portion 5 and protuberance 19 with the eye bolt member 8. As the terminal cover 13 is pushed downward over the terminal assembly 2, the protuberance .19 accommodates the movement therein of the eye bolt member 8, and the extended threaded portion 9 and the bolt 10 are received In the

stepped grooves

29, 30 of the projection 17. Also, the projection 18 provides the groove 37 to accommodate the movement thereth-rough of the arm portion 5 to a position in the recessed cavity 40 so that said arm portion will be so aligned with respect to the aperture 43 provided in the protruded section 36 that said terminal cover will not interfere with the spark gap esta lished between said arm portion and the lightning arrestor previously mentioned. The lip 24 then yields topermit the annular flange mounting base 4 to be received in the internal diameter 23 of the main body portion 16, and said lip then snaps over said annular flange mounting base to engageably secure the terminal cover 13 in place. The terminal cover 13 is prevented from rotating on the terminal assembly 2 due to the form-fitting feature of said terminal cover so that the arrestor gap hole, aperture 43 will not be misaligned with respect to the arm portion 5 and the lightning arrestor spark gap will thereby be maintained. Also, the indentations 46 and the rib sections 47 will provide a means of escape past the lip 24 for water which may enter the terminal cover 13 through the

apertures

14 and 43.

From the foregoing, it is now apparent that a novel terminal cover is provided meeting the objects set out hereinbe fore and that changes in the shape or configuration may be made by those skilled in the art without departing from the spirit of the invention, as defined by the claims which follow.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In combination with a terminal connecting a power line with an electrical bushing and having extended portions including a radially outwardly extending arm portion serving as an electrode for a lightning arrestor spark gap, a cover of insulating material substantially wholly enclosing said terminal and having an inner side wall portion in a plane spaced radially outwardly from the radially outer end of said arm portion, aperture means in said side wall port-ion providing limited access through said cover to said arm portion end preventing said cover from interfering with said spark gap, internal groove means in said cover receiving one of said extended portions and having opposed surfaces engageable with opposed sides of said one extended portion tosubstantially prevent rotation of said cover relative to said terminal and predeterminately maintain alignment between siad aperture means and said arm portion end, and other aperture means in said cover receiving said power line.

2. In combination with a terminal mounted on an electrical bushing including clamping means for connecting a power line to said terminal and a radially outwardly extending arm portion serving as an electrode for a lightning arrestor spark gap, a cover of insulating material having an inner Wall substantially wholly enclosing said terminal and having an inner side wall portion in a plane spaced radially outwardly from the radially outer end of said arm portion, an internal groove in said inner wall for receiving said clamping means, said groove having opposed side portions engageable with opposed sides of said clamp-ing means to substantially prevent rotation of said cover relative to said terminal, aperture means in said side wall portion providing limited access theret-hrough predeterminately aligned with said end of said arm portion to prevent said cover from interfering with said lightning arrestor spark gap, and other aperture means in said cover for receiving said power line.

3. In combination with a terminal mounted on an electrical bushing for connection with a power line and having extended portions including a radially outwardly extending arm portion serving as an electrode for a lightning arrestor spark gap, a cover of resilient insulating material having an inner wall substantially wholly enclosing said terminal, a groove in said inner wail for receiving said arm portion, said groove having opposed side portions engageable with opposed sides of said arm portion to substantially prevent rotation of said cover relative to said terminal, said groove having a bottom wall portion in a plane radially outwardly of and facing the radially outer end of said arm portion, first aperture means in said bottom wall portion providing limited access through said cover to said arm portion end and predeterminately aligned therewith to prevent said cover from interfering with said lightning arrestor spark gap, and second aperture means in said cover for receiving said power line.

4. In combination, a terminal having a body portion with mounting flange means thereon engaging an electrical bushing, a radially outwardly extending arm portion provided on said body portion serving as an electrode for a lightning arrestor spark gap, clamping means provided on said body for connecting a power line to said terminal, a non-conductive yieldable cover having an inner wall substantially wholly enclosing said terminal lip means on said cover for gripping engagement with said mounting flange means to secure said cover in enclosing relation with said terminal, first projection means on said cover defining a first internal groove for receiving said clamping means, second projection means on said cover defining a second internal groove for receiving said arm portion, said first and second grooves having opposed sides respectively engageable with opposed sides of said clamping means and said arm portion to substantially prevent rotation of said cover relative to said terminal, said second groove also having a bottom Wall in a plane radially outwardly of and facing the radially outer end of said arm portion, first aperture means in said bottom wall providing limited access through said cover and predeterminately aligned with said arm portion end to prevent said cover from interfering with said lightning arrestor spark gap, and second aperture means in said cover for receiving said power line.

References Cited by the Examiner UNITED STATES PATENTS 2,065,315 12/1936 Keath 1745 X 2,263,319 11/1941 Treanor 1745 X 2,715,654 8/1955 Lucas 174-77 2,834,829 5/1958 Broverman 174-138 2,875,267 2/1959 Sutton 174138 3,019,287- 1/1962 Newcomb et a1 l745 X 3,145,421 8/ 1964 Colbert.

LARAMIE E. ASKIN, Primary Examin r.

Claims

1. IN COMBINATION WITH A TERMINAL CONNECTING A POWER LINE WITH AN ELECTRICAL BUSHING AND HAVING EXTENDED PORTIONS INCLUDING A RADIALLY OUTWARDLY EXTENDING ARM PORTION SERVING AS AN ELECTRODE FOR A LIGHTNING ARRESTOR SPARK GAP, A COVER OF INSULATING MATERIAL SUBSTANTIALLY WHOLLY ENCLOSING SAID TERMINAL AND HAVING AN INNER SIDE WALL PORTION IN A PLANE SPACED RADIALLY OUTWARDLY FROM THE RADIALLY OUTER END OF SAID ARM PORTION, APERTURE MEANS IN SAID SIDE WALL PORTION PROVIDING LIMITED ACCESS THROUGH SAID COVER TO SAID ARM PORTION END PREVENTING SAID COVER FROM INTERFERING WITH SAID SPARK GAP, INTERNAL GROOVE MEANS IN SAID COVER RECEIVING ONE OF SAID EXTENDED PORTIONS AND HAVING OPPOSED SURFACES ENGAGEABLE WITH OPPOSED SIDES OF SAID ONE EXTENDED PORTION TO SUBSTAN-