Buckles – buttons – clasps – etc. – Clasp – clip – support-clamp – or required component thereof – With specific mounting means for attaching to rigid or...
Reexamination Certificate
1999-01-29
2001-04-10
Sakran, Victor N. (Department: 3626)
Buckles, buttons, clasps, etc.
Clasp, clip, support-clamp, or required component thereof
With specific mounting means for attaching to rigid or...
C024S0160PB, C024S03050P, C024S543000, C248S074300
Reexamination Certificate
active
06212742
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to protective fuse assemblies for liquid-cooled transformers, and more particularly, to drip trays used to capture oil that escapes the confines of a transformer tank when a submerged, bayonet-type fuse is removed from the transformer tank.
BACKGROUND OF THE INVENTION
Bayonet-style circuit breakers or fuses serve to protect an electrical system such as a transformer from overload (or transformer failure) resulting in a short circuit. With these devices, a fuse is inserted into a tubular fuse housing mounted in a tank and having a pair of contacts in its lower end. A typical fuse housing device is disclosed in U.S. Pat. No. 5,204,654, entitled “Fuse Housing Having Fluid Sealing Assembly,” and is hereby incorporated herein by reference in its entirety.
Bayonet-style fuses are designed to operate under oil and be easily replaceable after operation. They are installed by attaching it to one end of a fuse holder which is then pushed through the opening in the transformer tank wall and into the tubular fuse housing until the fuse is submerged in oil between the two contacts. The opposite (or upper) end of the fuse holder seals the top opening in the fuse housing. After the fuse has operated, the fuse and holder are withdrawn from the housing and a new fuse is attached to the holder and inserted.
While the foregoing design allows quick removal of the fuse, it requires the air-oil interface to be well below the tank wall opening to prevent oil from draining through the tank wall opening in the fuse housing as the fuse and fuse holder are withdrawn. Even with the air-oil interface below the tank wall opening, certain factors like heat and pad-tilt can cause the oil level to rise to a point above the opening in the tank wall. For example, on larger pad-mounted transformers, temperature induced oil height variations cause the oil level to fluctuate between approximately −2.5 inches and +3.25 inches on a 72 inch high tank. In addition, a pad-tilt angle of 2 or 3 degrees can shift the oil height an additional 1 inch on a 40 inch deep (front to back) tank.
When the fuse is removed, oil often escapes from the fuse housing opening causing contamination of the transformer oil and possible damage to rubber termination systems mounted onto the transformer front plate. This spillage is more likely when the oil height is elevated. It also is common for oil that has escaped to spill onto the floor on which the transformer is mounted. This, especially when unseen or not cleaned properly, results in a hazardous work environment for those who replace the fuses and others who work with or nearby the transformer tanks.
Consequently, devices for capturing the oil that escapes the confines of the transformer tank when the fuse is removed have been designed and implemented to alleviate the problems resulting from dripping oil. Such devices, called drip guards or drip trays, usually are mounted to the upper end of the fuse holder just outside the wall of the transformer to prevent dripping of oil or other insulating fluids onto molded rubber terminators, cables and arresters during removal of the bayonet-style fuses. The trays protect rubber products that may not be chemically compatible with the dielectric fluid.
One such drip tray is the RTE® Bay-O-Net Fuse Assembly Drip Guard, manufactured by Cooper Power Systems, Inc. of Waukesha, Wis. Another is a drip tray manufactured by Central Moloney, Inc. of Pine Bluff, Ark. A third is an oil drip shield manufactured by Howard Industries, Inc. of Laurel, Mass.
One drawback of these conventional drip trays, however, is that they are cumbersome to operate and mount on a fuse holder, typically requiring two free hands. Another drawback of these conventional drip trays is that they do not have or maintain a firm mount on the fuse holders. It is, therefore, desirable to provide a clamp for drip tray that facilitates mounting of the drip tray on a fuse holder and improves the strength of the mount itself.
SUMMARY OF THE INVENTION
A clamp for mounting a first article to a second article is provided. The clamp has only two connecting members which are a first arm and a second arm. The first arm comprises a proximal end attached to the first article and a distal male end. The second arm comprises a proximal end attached to the first article and a distal female end.
The male end comprises an insertion member, a male mating detent protruding from the insertion member, and a male locking detent protruding from the male end. The female end comprises a receiving member, a female mating detent protruding from the receiving member, and a female locking detent protruding from the receiving member. When the insertion member mates with the receiving member, the male mating detent and the female mating detent align, and the male locking detent and the female locking detent align so that the clamp becomes locked in three perpendicular directions.
Preferably, the clamp of the present invention is used for mounting a drip tray to a transformer fuse holder. In this preferred embodiment, the drip tray is the first article and the fuse holder is the second article.
In a preferred embodiment, when the insertion member mates with the receiving member, the male end and female end are in a single plane and the male mating detent, the female mating detent, the male locking detent and the female locking detent prevent the male end and the female end from moving out of the single plane. In addition, a preferred clamp further comprises a base portion situated between the proximal ends and the first article to connect the arms to the first article and aid in mounting the first article to the second article.
Preferably, the clamp's receiving member further comprises a base lip portion having a proximal end attached to the second arm, a narrow arched member having a proximal end and distal end, the proximal end of the arched member extending from the proximal end of the base lip portion, and a tip extending from the distal end of the arched member so that the base lip portion, the arched member and the tip define a receptacle within which the insertion member can be received.
In addition, the clamp's arched member preferably is flexible so that when the arched member is flexed from its natural state, the insertion member can gain access to the receptacle, yet properly mate with the receiving member when the arched member is in its natural state. When the arched member is not flexed, the receptacle has a substantially triangular-shaped cross section when viewed from a front perspective, the insertion member is an insert having a substantially triangular-shaped cross section when viewed from the front perspective.
Another feature of the preferred embodiment of the clamp is that the tip of the receiving member has a substantially triangular-shaped cross section when viewed from the front perspective, and the receiving member has a substantially C-shaped cross section when viewed from the front perspective. The first arm and second arm also are preferably flexible such that they can be flexed to surround the second article.
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RTE Bay-O-Net Fuse Assembly Drip Guard, Electrical Apparatus 240-41, manufactured by Cooper Power Systems, Inc. of Waukesha, Wisconsin [Apr. 1996].
Brochure for “Tuf-Cup Drip Shield For Bayonet Fuse Holde
ABB Power T & D Company Inc.
Sakran Victor N.
Woodcock Washburn Kurtz Mackiewicz & Norris LLP
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