Dimmer having a thermally insulated faceplate fastener
Application no:10143438 -
Filed date:2002-05-10 -
A light dimmer capable of receiving a faceplate fastener while thermally insulating the fastener from a heat-generating device, such as a triac or a field-effect transistor, is presented. In a preferred embodiment, the dimmer includes a thermally insulating boss integrally formed with the body of the dimmer such that the boss includes a fastener-receiving aperture adapted to be axially aligned with the fastener-receiving openings of the faceplate. In addition, the dimmer includes a heat-dissipating aluminum yoke to which the heat-generating device is in thermal communication, thereby allowing the yoke to act as a heat sink. The yoke has a fastener-receiving aperture formed therein in axial alignment with the fastener-receiving aperture of the thermally insulating boss, with the yoke fastener-receiving aperture proportioned to receive the fastener therethrough in non-contacting relationship.
What is claimed is:
1. A light dimmer including a heat generating device in thermal communication with a heat dissipating yoke, a body portion secured to the yoke and enclosing at least a portion of the heat generating device, the yoke defining a first aperture for receipt of a faceplate fastener therethrough, the improvement comprising: said first aperture adapted to receive said fastener therethrough in non-contacting relationship; and said body portion further comprising a thermally insulating boss defining a second aperture in axial alignment with said first aperture, said second aperture adapted to receive said faceplate fastener in contacting relationship; whereby said faceplate fastener received in said second aperture is thermally insulated from said heat generating device and said heat dissipating yoke.
2. The dimmer of claim 1 wherein no part of said boss extends into said first aperture.
3. The dimmer of claim 1 wherein a portion of said boss extends into said first aperture.
4. The dimmer of claim 3 wherein a portion of said yoke defining said first aperture further defines a substantially planar surface adapted to face toward a faceplate, said surface substantially normal to a central longitudinal axis of said second aperture; and said portion of said boss extending into said first aperture extends to a point no further than said surface.
5. The dimmer of claim 3 wherein said portion of said boss extending into said first aperture extends beyond said yoke and is adapted to contact a faceplate so as to maintain said faceplate at a predetermined distance from a portion of said yoke immediately adjacent said first aperture when said faceplate is secured to said dimmer.
6. The dimmer of claim 1 wherein said boss defines first threads adapted to cooperatively engage corresponding threads defined by said faceplate fastener.
7. The dimmer of claim 1 wherein said second aperture comprises an elongated smooth bore.
8. The dimmer of claim 7 wherein said bore has a diameter less than a diameter of said fastener.
9. The dimmer of claim 1 wherein said boss is formed as an integral part of said body portion.
10. The dimmer of claim 1 wherein said boss comprises electrically non-conductive material.
11. The dimmer of claim 1 wherein said boss comprises thermoplastic material.
12. The dimmer of claim 11 wherein said thermoplastic material comprises Noryl.
13. The dimmer of claim 1 wherein said boss has a thermal conductivity of no greater than about 0.30 Watts per meter degree Celsius.
14. The dimmer of claim 13 wherein said boss has a thermal conductivity no greater than about 0.25 Watts per meter degree Celsius.
15. The dimmer of claim 1 wherein said boss further defines a fastener retaining element adapted to releasably engage said fastener in frictional relationship when said fastener is forcibly urged into said second aperture.
16. The dimmer of claim 15 wherein said boss defines first threads adapted to cooperatively engage corresponding threads defined by said faceplate fastener.
17. The dimmer of claim 15 wherein said second aperture comprises an elongated smooth bore.
18. The dimmer of claim 17 wherein said bore has an inner diameter smaller than an outer diameter of said fastener.
19. In a light dimmer including a heat generating device in thermal communication with a heat dissipating yoke, a body portion secured to the yoke and enclosing at least a portion of the heat generating device, the yoke defining a first aperture for receipt of a faceplate fastener therethrough, a method for limiting the temperature rise of the fastener relative to ambient environmental conditions, comprising the steps of: adapting said first aperture to receive said fastener therethrough in non-contacting relationship; and providing a thermally insulating boss in said body portion, said boss defining a second fastener-retaining aperture in axial alignment with said first aperture, said second aperture adapted to receive said fastener in contacting relationship.
FIELD OF THE INVENTION
The invention relates to the fastening of faceplates to heat-dissipating electrical power switching devices, and more particularly, to thermally conductive faceplate fasteners securing faceplates to electrical light dimmers.
BACKGROUND OF THE INVENTION
A typical prior art electrical light dimmer
For attaching the faceplate
Because the screws
In normal operation, this results in the screws
SUMMARY OF THE INVENTION
In accordance with the present invention, a dimmer capable of having a faceplate attached thereto by means of fasteners that are thermally insulated from any heat generating devices internal to the dimmer is presented. By thermally insulating the fasteners from any heat generating devices and their associated heat sinks, the faceplate fasteners remain at a temperature closer to that of ambient.
In addition, by thermally insulating the faceplate fasteners from any heat generating devices and heat sinks, the manufacturing of the dimmer can be simplified with a resulting lower manufacturing cost because, for example, there is no longer any need to thread the yoke.
In one embodiment, the dimmer includes a heat dissipating yoke having a first aperture therethrough for allowing the fastener to extend through or past the yoke without contacting the yoke in thermal relationship. The dimmer includes a boss defining a second aperture in axial alignment with the first aperture for receiving the fastener therein. The boss is made of a thermally insulating material, preferably having a thermal conductivity no greater than a predetermined value, such as a thermoplastic, and has a portion that extends through the first aperture to a point flush with a faceplate confronting surface of the yoke.
These and other features and advantages of the present invention will be more readily apparent from the detailed description set forth below taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is further described in the detailed description that follows, by reference to the noted drawings by way of non-limiting illustrative embodiments of the invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:
In the following description, the same or similar elements are labeled with the same or similar reference numbers.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
In accordance with the present invention, a dimmer
The dimmer body portion
In a preferred embodiment, the boss
Aluminum may typically have a thermal conductivity on the order of about 237 W/mÂ° C., while steel may typically have a thermal conductivity on the order of about 60 W/mÂ° C. The boss
The second aperture
Turning now to
Turning now to
Turning now to
Turning now to
Although the boss
It is to be understood that the foregoing illustrative embodiments have been provided merely for the purpose of explanation and are in no way to be construed as limiting the invention. Words that have been used herein are words of description and illustration, rather than words of limitation. Further, although the invention has been described herein with reference to particular structure, materials and/or embodiments, the invention is not intended to be limited to the particulars disclosed herein. Rather, the invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. Those skilled in the art, having the benefit of the teachings of this specification, may effect numerous modifications thereto and changes may be made without departing from the scope and spirit of the invention.
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