Electrical connectors – Interrelated connectors relatively movable during use – Movement about axis
Reexamination Certificate
1999-03-18
2001-02-13
Bradley, Paula (Department: 2833)
Electrical connectors
Interrelated connectors relatively movable during use
Movement about axis
C340S949000
Reexamination Certificate
active
06186796
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field on the Invention
The present invention relates in general to windcone lighting devices and, in particular, to swivel devices.
2. Description of the Prior Art
Various types of windcones to indicate wind direction and velocity have been in use at airports around the world. Normally, these windcones, being rotatably about a vertical axis mounted on an upright pole, utilize a truncated conical framework provided with a windsock. The air current passing through the windsock causes it to distend leewardly and point windwardly. The degree of expansion of a windsock, by the wind passage, constitutes an indicator of the wind velocity.
Since aircraft landing occurs both in daylight and at night, it is critical that windcones be well illuminated for night time visibility. Therefore, a lighting fixture, comprising a bulb, is adapted to illuminate the interior of the windsock directly, and thereby, to provide an indication of the wind direction and velocity, even in hours of darkness. The windsock is formed from a suitable fabric material, so that the light rays from the bulb would be visible through the cone.
As can be seen from the above, the use of a single light, that directly illuminates the windcone with which it rotates, provides adequate illumination, regardless of the wind direction
The connection between the upper part of the fixed upright pole and the rotatably mounted windcone and the connection between a fixed electrical power supply and the light fixture, which rotates with the cone, is provided by a swivel device. This device, which constitutes the most important part of a windcone assembly, is exceptionally vulnerable due to its direct exposure to unobstructed heavy wind, rain, snow and, implicitly, changes of temperature.
Attempts have been made in the past to introduce a better swivel device. U.S. Pat. No. 4,553,430, dated Nov. 19, 1985 and granted to Behrens for “Illuminated windsocks for airports” teaches the use of a spotlight bulb directed along the horizontal axis of the windsock. The bulb may be mounted directly to a rotating axle, coaxially with the supporting post, or can be carried by radial arms attached to the circular framework of the windsock. There are obvious disadvantages to Behren's design. First, the electrical fixture, used for illumination, is energized by electrical conductors which terminate in conventional alligator-type electric clips, slidably attached to a slip ring assembly. It is known that the use of brushes is more reliable and efficient. Second, use is made of an upright axle with upper and lower bearings, rotatably supported on the axle. Each of the bearings has a radially extending rod which is welded to a rim of windsock framework. Thus, the distance between the bearings is substantial, the length of the upright axle being commensurate with the larger diameter of the windsock. Due to this design and to the fact that the assembly, alligator clips-slip rings, is located beyond the two bearings, above the upper one, this device lacks compactness.
U.S. Pat. No. 4,486,754, dated Dec. 4, 1984 and granted to Guggemos for a “Lighted windcone for evacuation aid” discloses a windcone lighting device. Here, a tubular shaft is mounted on top of an upright pole, firmly attached to a base. The windcone is rotatably mounted on the tubular shaft, the mounting comprising a pair of vertically spaced bearings. A bracket is attached to each outer race of these bearings for joining and rotating with the windcone. An assembly, slip rings-brushes is located above the upper bearing. A lamp support conduit, which assumes a generally “J” shape, connects the brushes to a light and rotates with the windcone. In another embodiment, there is lamp support located between the brackets, within the windcone. Guggemos structure has the same shortcomings as Behrens structure Moreover, the use of a lamp support conduit or a lamp support which do not form a unitary rigid structure with the slip rings-brushes assembly constitutes another shortcoming.
SUMMARY OF THE INVENTION
There is, accordingly, a need for a swivel device which overcomes or, at least alleviates, the disadvantages of the prior art.
The present invention is basically directed to a swivel device which comprises a rotating housing, provided with means for drainage of condensation from its interior to its exterior, and a fixed axle on which the rotating housing is supported through two spaced bearings. Used is made of means for providing electrical insulation between a pair of slip rings and the fixed axle, while in the interior of the rotating housing, brush means is attached. There is also means for preventing electrical leakage from or to the brush means, and for protecting electrical conductors extending from the interior of the fixed axle to the pair of slip rings.
In one aspect of this invention, the rotating housing has an upper, reduced diameter cavity and a lower, larger diameter cavity. In the lower, larger diameter cavity is provided in its wall, along its whole length, a longitudinal channel for collecting and draining condensation and allow breathing. The lower, larger diameter cavity is also provided, laterally, with an opening which ends in a machine finished surface. To this surface is attached a flange cover. A drainage slot is indented in the machine finished surface, at its lower end, parallel to the longitudinal axis of the rotating housing. When the flange cover is attached to the machined surface, a connecting passage between the interior of the lower, larger diameter cavity and the exterior is formed.
In another aspect of this invention, the fixed axle is of hollow type and is provided with a bore which starts from the middle of the surface of its central position and extends inwardly, perpendicular to the longitudinal axis of the fixed axle, until it reaches its hollow interior.
In another aspect of this invention, the means for providing electrical insulation between the fixed axle and the pair of slip rings includes a first split bushing mounted directly on the fixed axle, between the two bearings. A second split bushing, made also of insulating material is mounted on the first split bushing with its slit coinciding with the bore in the fixed axle. The position of the slit of the first split bushing is offset with respect to the slit of the second split bushing. The second split bushing is provided with two circular channels for snuggly fitting the pair of slip rings.
In another aspect of this invention, the brush means includes brushes of carbon impregnated with 50% copper. The brushes are located in brass guides which are pressed in brush holders. The brush holders are introduced and firmly attached in a brush holder carrier which is attached to the rotating housing to face the pair of slip rings.
In another aspect of this invention, the means for preventing electrical leakage from and to the brush means includes an insulating coating. This coating is applied on the surface of the brush holder carrier which faces the pair of slip rings, and, especially, around the brush holders.
In another aspect of this invention, the means for protecting electrical conductors, which extend from the interior of the fixed axle to said pair of slip rings, includes a conductor bushing of insulating material which passes through the slit of the second split bushing and is also inserted in the first split bushing and in the bore of the fixed axle.
REFERENCES:
patent: 4423549 (1984-01-01), King
patent: 4486754 (1984-12-01), Guggemos
patent: 4847528 (1989-07-01), Eguchi et al.
patent: 4871049 (1989-10-01), Okita
patent: 5833482 (1998-11-01), Buchter
Bradley Paula
Gilman Alexander
Kaufman Frederick
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