Patent Application
20150204520
1. Field
The subject disclosure relates to electric lighting fixtures and more particularly to such fixtures employing an indirect LED light engine featuring a dome-shaped heat sink.
2. Related Art
Lamps or light fixtures have been provided in the prior art which employ an Edison-type incandescent bulb or other traditional light source with a socket positioned within a surrounding lamp shade.
An indirect LED light engine according to an illustrative embodiment may comprise a printed circuit board mounting one or more LEDs, a dome-shaped heat sink component having an internal mounting structure for mounting the printed circuit board, the mounting structure having a central opening therein, a heat conductive tube mounted in the central opening, and a lens component mounted over the one or more LEDs and having an opening therein through which the heat conductive tube protrudes. Such a light engine may be located within a lamp shade to create, for example, a pendant light. In one such embodiment, the light engine is suspended from a junction box located within the lamp shade, and an undersurface of the junction box is adapted to receive light transmitted from the LEDs and to reflect all or a portion of that light in a desired or selected manner.
The PCB 15 provides a mounting surface or mounting board for one or more LEDs 35 and attendant electrical circuitry such that, in one embodiment, the LED light is directed upwardly. In one embodiment, the top surface of the PCB 15 lies just below the top rim 39 of the heat sink 13. In one embodiment, the PCB may be FR4 material, but may be other materials, for example, metal clad to better facilitate heat transfer.
In one embodiment, the dome-shaped heat sink 13 may be a single or unitary part or component formed of die cast aluminum alloy such as A380 alloy or other suitable material and includes a number of curved external heat sink fins, e.g., 21 disposed adjacent one another and running generally vertically downward and then curving in towards a central area 23 at the bottom of the dome 13. The interior 25 of the dome-shaped heat sink 13 includes four vertically disposed bosses 27 for threadably receiving respective screws 29, which attach the PCB 15 to the heat sink 13. Radial ribs 31 and circumferential ribs 33 unitarily formed with the four bosses 27 provide a web structure which adds support to the four bosses 27 and which assists in conducting heat generated by the LEDs 35 from the circuit board 15 to the central aluminum tube 17 and to the dome for heat transfer and dissipation purposes.
The dome-shaped heat sink 13 further includes a central receptacle or boss 41, which receives the aluminum tube 17. In the illustrative embodiment of
In one embodiment, the lens or lens cover 19 may be convex and formed, for example, of transparent or translucent polycarbonate material. In one embodiment, the lens 19 functions to protect the LEDs but may also serve to contribute to the optical characteristics of the device in other embodiments.
A junction box or “J-Box” cover 59 is mounted in a central circular opening 57 (
The shade cover component 65 serves to cover the opening 57 of the shade 53 and, in various embodiments, may be sized to cover various sized legacy openings of various shapes and sizes of conventional shade covers, e.g., in retrofit applications. In some embodiments, a shade cover component 65 may not be needed.
To hold the nipple 67 in place, the second lock nut 66 is threaded onto the nipple 67 against the top surface of the J-Box cover 59, as shown in
The cord retainer 71 may be standard off-the-shelf part which crimps onto the power cord 69. The retainer 71 is wider than the opening in the nipple 67 and thereby prevents the cord 69 from being drawn through the nipple 67.
As illustrated in
In one embodiment, the LEDs 35 may comprise six (6) Cree XTE model LEDs with a maximum rating of 4½ watts, operating at about 1 watt each. Various other numbers and types of LEDs may be used in various embodiments.
Thus, in the illustrated pendent light embodiment, the light engine is suspended from a junction box located within the lamp shade 51, and an undersurface 101 of the junction box is adapted to receive light transmitted from the LEDs 35 and to reflect all or a portion of that light in a desired or selected manner, one such manner being light rays 103 from the LEDs 35 reflected off the under surface 101, as illustrated in
A number of variations to the illustrative embodiments described above may be made, for example:
Thus, those skilled in the art will appreciate that various adaptations and modifications of the just described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.
