TECHNICAL FIELD OF THE INVENTION

[0001] The present invention generally relates to both thermal management and positioning control of a sealed luminaire. More specifically to a remote control aligning of an optical system while at the same time controlling the heat in a sealed system.

BACKGROUND

[0002] Outdoor luminaires designed for mounting in or on the ground (in grade) or in other locations outside are well known. A fundamental requirement of such luminaires is that they be sealed or protected against rain and other adverse weather. This is usually accomplished by encasing the luminaire in an environmentally shielded outer casing. These enclosures are readily available with various ratings to suit all weather conditions up to a completely sealed enclosure. The US uses the NEMA classification system to specify the degree of protection offered by an enclosure, while many other countries use the IP (International Protection) marking system for the same purpose. It is also a common customer desire to be able to adjust the position of such a luminaire so as to accurately focus it onto a building or other architectural structure. This is easily accomplished if the enclosure is movable or installed in such a way that it can be positioned easily. However, there is a problem if the luminaire enclosure is installed in a fixed position as often happens, for example, when a luminaire is installed in-grade or partially buried in the ground. Such luminaires, which are commonly seen in pavements, floors and other surfaces, are typically positioned such that only their upper, output, surface is visible and is flush with the grade level. The rest of the luminaire is below the ground. Such an installation presents a problem in positioning the angle of the luminaire beam. The luminaire body cannot be moved, it's in the ground, so some other system for positioning the beam within the outer enclosure has to be provided. Very often it is necessary to open the outer enclosure of the luminaire to access these positioning systems, this breaks the seals on the NEMA or IP rated enclosure and can cause subsequent leaks or failures of the enclosure system.

[0003] The recent introduction of LED based luminaires has exacerbated this problem. An LED luminaire typically requires a heat sink to help maintain the temperature of the LEDs themselves. Very often the heat is taken away from the LEDs and led to a large heat sink, or to the outer enclosure of the luminaire itself. If we now want to alter the position of the light beam from the LEDs by moving the LEDs we have to do so in a way that doesn't affect this heat path to the heat sink and cause overheating of the LEDs. Some prior art devices achieve this by making the outer enclosure much larger than it otherwise needs to be so as to accommodate the movement of the LEDs and associated heat sink within. Such a system still requires opening the unit and breaking the seals on the sealed enclosure.

[0004] It would be advantageous to provide a positioning system for a sealed luminaire that allowed positioning of the light beam without breaking the seal on a sealed rated enclosure, that minimized the size of the enclosure, and that didn't affect the thermal management of the light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings in which like reference numerals indicate like features and wherein:

[0006] FIGURE 1 illustrates an embodiment of the invention;

[0007] FIGURE 2 illustrates an embodiment of the invention showing the positional control system;

[0008] FIGURE 3 illustrates an embodiment of the invention showing the positional control system;

[0009] FIGURE 4 illustrates an embodiment of the invention showing the positional control system;

[0010] FIGURE 5 illustrates an embodiment of the invention as mounted within an

enclosure;

[0011] FIGURE 6 illustrates an embodiment of the invention as mounted within an

enclosure; and

[0012] FIGURE 7 illustrates an embodiment of the invention fully assembled within an enclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present invention are illustrated in the FIGURES, like numerals being used to refer to like and corresponding parts of the various drawings.

[0014] The present invention generally relates to positioning a sealed luminaire, and more specifically to a remote control system for aligning an optical system within a sealed system without compromising thermal management.

[0015] Figure 1 illustrates an embodiment of the main features of the invention in a luminaire. Light module 100 contains light sources 20 that are mounted on substrate 22 and heat conducting plate 23. Light sources 20 may be LEDs and may include optical systems such as TIR lenses. Six light sources 20 are illustrated here, however the invention is not so limited and any number of light sources may be used. Heat conducting plate 23 is, in turn, connected to heat sink 24. Heat sink 24 has a hole 25 through which passes heat pipe 26. Heat pipe 26, in turn, is in thermal contact with fixed external heat sink 27. Fixed external heat sink 27 may be the external casing of the luminaire. Heat pipe 26 is of a type well known in the art which uses both thermal conductivity and phase transition of a working fluid from liquid to vapor phase and back to efficiently transport heat. Heat pipe 26 may be a capillary heat pipe, a wicking heat pipe or other heat pipe as well known.

[0016] Heat pipe 26 has a circular cross section where it passes through heat sink 24 at hole 25. The clearance between heat pipe 26 and heat sink 24 at hole 25 is small but large enough such that heat sink 24 may rotate about heat pipe 26. Any gap between heat pipe 26 and heat sink 24 is filled with a heat conducting paste such that a good thermal path exists between heat sink 24 and heat pipe 26 as one rotates about the other, and at all angles of rotation. [0017] As the thermal path remains unbroken at all positions there is no requirement for external heat sink 27 to move, thus this may be a fixed portion of the luminaire such as the outer casing without compromising the ability to position the light beam. This allows the luminaire enclosure to be smaller than the prior art where the entire light module, including heat sink, has to be given room to move.

[0018] In the illustrated embodiment a second heat pipe 26 continues out of the far side of heat sink 24 to provide a second heat-conducting path. The invention is not so restricted and any number of heat pipes may be used as required.

[0019] Rotation of heat sink 24 about heat pipe 26, and thus altering the beam position of attached light sources 20 may be affected manually through opening the luminaire, or may advantageously be affected through the use of a motor 30. Motor 30 is configured as a linear actuator through lead screw 32. As motor 30 rotates lead screw 32 will extend or retract as desired. Lead screw 32 is connected through bracket 40 to heat sink 24 and thus to light sources 20. Motor 30 is mounted through brackets 34 and 36 to the body of the luminaire (not shown). Bracket 40 is free to pivot about axis 42 and bracket 34 is free to pivot about axis 38. Motor 30 is here shown as a linear actuator but may be of a type selected from, but not restricted to, stepper motor, servo-motor, actuator, solenoid, and other motor types well known in the art. Other methods of motorizing the position of heat sink 24 and light sources 20 are also envisaged as well known in the art.

[0020] Figures 2, 3 and 4 show a simplified diagram of the invention with the angle of heat sink 24 and thus light sources 20 in different positions. In Figure 2 the system is in its central position with the light sources facing vertically upwards. In Figure 3 motor 30 has been operated so as to pull in lead screw 32 as shown by arrow 50 and thus lower pivot point 42. Heat sink 24 is thus caused to rotate around heat pipe 26 where it passes through the heat sink 24 at hole 25. The light sources are thus angled to the right.

Similarly, in Figure 4 motor 30 has been operated so as to push out lead screw 32 as shown by arrow 50 and thus raise pivot point 42. Heat sink 24 is thus caused to rotate around heat pipe 26 where it passes through the heat sink 24 at hole 25. The light sources are thus angled to the left. Although only three positions have been shown, in practice any position of heat sink 24 and thus light sources 20 may be achieved.

[0021] Motor 30 may be operated through a remote control system such that the luminaire enclosure can remain sealed. This remote control could be communicated through DMX-512, RDM, ACN or any other protocol as well known in the art. In other embodiments control of motor 30 could be through switches inside the enclosure that are operated by external magnets, through sealed control buttons, through radio control, through ultrasonic control, through optical communication, or other communication means as are well known in the art.

[0022] In practice it is likely that the luminaire will only need positioning once, when it is installed. However the system allows for future repositioning without breaking the seals on the enclosure.

[0023] Figure 5 illustrates an embodiment of the invention as it may be mounted in an enclosure. Light module 100 containing light sources 20, heat sink 24, heat pipe 26 and motor system 30 is connected to fixed heat sink 27 which, in turn when slid into housing 50 is in thermal contact with housing 50. Light sources 20 may be fitted with a bezel 52.

[0024] Figure 6 illustrates an embodiment of the invention as it may be mounted in an enclosure. Light module 100 containing light sources 20, heat pipe 26 and the remainder of the invention is installed within housing 50. Sealing cap 54 and front window 56 may be secured over the assembly. [0025] Figure 7 shows the final assembly of an embodiment of the invention. Light module 100 within its housing and fixed heat sink is installed inside outer sealed enclosure 60, capped by window 56 and sealing ring 58. Light module 100 is free to tilt in position within housing 50 and enclosure 60 while maintaining thermal contact through heat pipes to the housing and external heat sink.

[0026] While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this invention, will appreciate that other embodiments may be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.

[0027] The invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the invention as described by the appended claims