Optics: image projectors – Housing
Reexamination Certificate
1999-04-09
2001-09-04
Metjahic, Safet (Department: 2858)
Optics: image projectors
Housing
Reexamination Certificate
active
06283600
ABSTRACT:
BACKGROUND OF THE INVENTION
In the field of ornamental lighting, a recently recognized application exists in the use of large scale image projecting fixtures. These involve a permanently located fixture directed toward a large planar surface such as a building side and including not only a lamp within the fixture to illuminate the surface but provision for mounting a photographic transparency and suitable focusing optical system for projecting the image of the transparency on the wall or surface which now becomes a changeable work of art.
The basic concept is deceptively simple. In carrying out the design of such projector system, however, one must first provide a weather-tight enclosure and one, which maintains the weather tight connection when it is illuminated or not and whether exposed to sub freezing or 100-degree Fahrenheit temperature. The fixture must maintain its focus despite such temperature changes and to be relatively immune to interference by vandals.
A further need is that the exchanging of lamps and the exchanging of photographic transparencies or other image source must be clone simply and rapidly without the intervention of a skilled projectionist. Often the maintenance of exterior lighting is delegated to groundskeepers and electricians who have many other duties and are not in a position to devote much time or attention to exchanging lamps or image media while having to maintain proper focus and direction of the fixture. Often the exchange of lamps or image media might be done during daylight hours when it would be difficult and possible to precisely check the focus and direction of the fixture. Such requirements are not present for most other exterior lighting.
BRIEF DESCRIPTION OF THE INVENTION
Faced with the above state-of-the-art, it appears that it should be possible, with proper design, to make a light projector, which meets the requirements of:
1. A weather-tight housing;
2. An easily exchangeable lamp assembly;
3. An easily exchangeable photographic transparency or template mount;
4. An easily focused optical system;
5. Accepts a variety of optical filters for special effects;
6. An easily directed fixture assembly which maintains its projection field despite adverse conditions such as wind, unintentional bumping by passers by or intentional acts of vandals;
7. A fixture which maintains its focus and direction despite dramatic changes in ambient temperature;
8. A fixture in which the acts of the focusing, exchanging photographic transparencies or templates can be accomplished by regular lighting maintenance personnel;
9. Allows rotation of the projected image and exchanging lamps to be accomplished singly or at the same time without interference with any of the other adjustments; and
10. A fixture achieving each in the above the while employing relatively high light output, low wattage lamps which are capable of providing the required quality image on the projection surface.
Accomplishing all these objectives in a high quality yet economical fixture design provided a very real challenge. However the challenge was met by two different but related projector designs for different types of lamps. In the first embodiment, the projector includes the combination of a central body with the lamp housing at its rear, a photographic slide or template mount in its central section, an optical lens assembly section and an exterior front window and shroud, each of which are secured to their adjacent section by an O ring sealed joint and concealed locking screws.
To satisfy the requirements of requirement 6 above requires that structure of the light projector be as small and compact as is practical and yet physically rugged. The small size serves to make the projector relatively unobtrusive. To gain the advantage of retaining focus despite large variations in temperature requirement 7 above the rugged structure must also serve as an effective heat sink.
The lamp house is mounted to the rear without interference with the slide or template mount assembly, the optics or the sealed front shroud and window. A replacement lamp may be inserted into its socket for properly illuminating a transparency in the focal plane mount. The lamps used, ideally, include an internal reflector so that no problems of orientation of the replacement lamp with its reflector are encountered. Replacement of the rear lamp house assembly is accomplished by loosening a screw and sliding the lamp house rearward. Removing the lamp (unshown and replacing it followed by reinserting the lamp house into the central body) does not affect the transparency mounting nor the focus nor the front sealed end window. A suitable ring and locking screw secure the lamp assembly in place.
Removal of the front shroud and window by a release of its locking screw and sliding over its O ring seal exposes the optical assembly and the template or image media mount. The optical assembly is locked at its previously focused position by a setscrew and will not be affected by the removal and replacement of the transparency or template. The transparency or template mount employs spring pressure to hold the transparency or template in the focal plane.
By releasing the locking set screw in the optical system, the focus may be adjusted and locked in place and the front shroud returned to its normal position with illumination exiting by its sealed front window.
The direction of the beam from the fixture and the resulting image is determined by rotation of the fixture base about a vertical axis and about a horizontal axis in its U-shaped mount. In both cases locking screws for azimuth and elevation adjustments are concealed from view by portions of the fixture. When adjusted in azimuth and elevation angles and the locking screws engaged, the fixture is permanently focused, sealed and directed until the next service visit.
The screws securing the rear housing and optical assembly are protected from unauthorized removal by the outer sleeve. This sleeve itself is secured to the mounting yoke of the projector by concealed release locking screws.
In an alternate embodiment, rotation of the image is accomplished by a different means. The projector is secured to its support yoke by a separate tubular sleeve which surrounds the body of the projector and is secured to the body by locking screws. Unloosening the locking screws allows the entire projector body and the image produced to be rotated similar to rotation of the cross hairs of an optical sight. No seal of the projector is opened or “broken” in any image rotation adjustment.
Relamping of the alternate embodiment is accomplished by means of a locking ring and O ring seal which are merely released by unthreading the locking ring, sliding the rear housing off with the old lamp exposed, removing it and replacing it with a new lamp, sliding the rear housing into place and tightening the locking ring. None of the focus, orientation angle of the projector or the image orientation are affected.
In the alternate embodiment, the projector is thermally isolated from the supporting yoke and base by merely line and point contact engagement of the projector middle housing with the surrounding sleeve.
In both embodiments, the projector is attached to its yoke by an easily adjusted locking nut on each side of the yoke which can be released only through the unique usage of an allen wrench inserted in a tangential opening and net used as a wrench but rather as a moment arm. The lock nuts are smooth and cannot be released without the additional moment arm of the allen wrench used as an extension arm rather than a wrench. Any attempt to use an allen wrench in its normal unscrewing action only results in useless turning of the wrench. A vandal is unlikely to ascertain the necessary tool and necessary mode of release to loosen the lock nuts.
REFERENCES:
patent: 4682868 (1987-07-01), Constantin et al.
patent: 5295056 (1994-03-01), Peck
patent: 5404283 (1995-04-01), Yantz et al.
patent: 5791755 (1998-08-01), Henry et al.
patent: 5947590 (1999-09-01), Meuse et al.
Bernardo Sam
Cooper Technologies Company
Leroux E P
Metjahic Safet
Wagner John E.
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