Abstract:
An image projector includes a generally cylindrical housing containing a slide or pattern holder, a fixed lens and an adjustable lens. A separate lamp house threadedly engaged with the housing contains a lamp and electrical connections to the lamp. A cylindrical forward housing or shroud is threadedly engaged with the housing at its opposite end and includes a window through which the light pattern is transmitted. Seals are incorporated adjacent to the threaded connections to assure weather tight operation. The housing is carried in a sleeve which is spaced to allow air circulation around the housing. The sleeve is carried in a yoke which permits elevational adjustment of the projector.

Description:
REFERENCE TO RELATED APPLICATION 
     This application relates to provisional application Ser. No. 60/081,630 filed Apr. 13, 1998. 
    
    
     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. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention may be more clearly understood from the following detailed description and by reference to the drawings in which: 
     FIG. 1 is a perspective view of a lamp housing in accordance with this invention shown operating as an image projector on a building side wall; 
     FIG. 2 is a side elevational view of the projection fixture of this invention; 
     FIG. 2A is a side elevational view of the projection fixture of FIG. 2, configured for ground installation and including a safety lanyard for the removable front housing or hood member; 
     FIG. 3 is a longitudinally exploded elevational view of the fixture of this invention; 
     FIG. 4 is a front elevation view of the fixture of FIG. 1; 
     FIG. 5 is a rear elevational view of this invention; 
     FIG. 6 is a vertical elevational view of the main body assembly of this invention and taken along line  6 — 6  of FIG. 3; 
     FIG. 7 is a longitudinal diametrical sectional view of the main body section of this invention taken along lines  7 — 7  of the FIG. 3; 
     FIG. 8 is a longitudinal diametrical sectional view of an alternate embodiment of the fixture of this invention designed particularly for use with metal halide lamps; 
     FIG. 9 is a side elevational view of the base of the fixture of FIG. 8; 
     FIG. 10 is a front elevational view of the base of FIG. 9; 
     FIG. 11 is a diametrical sectional view of the base of FIG. 9 configured for a PAR 20 type lamp; 
     FIG. 12 is a diametrical sectional view of the locking ring of the fixture of FIG. 8; 
     FIG. 13 is a longitudinal sectional view of the pattern holder assembly of the fixture of FIG. 8; 
     FIG. 14 is a longitudinal sectional view of the inner housing assembly of the embodiment of FIG. 8 of this invention; 
     FIG. 14A is a front elevational view of a typical slide or template holder used in the projectors of this invention; 
     FIG. 15 is a front elevational view of the mounting sleeve of the embodiment of FIG. 8; 
     FIG. 16 is a diametrical sectional view of the sleeve of FIG. 15; 
     FIG. 17 is an exploded view, partly in section, of the outer housing, projection lens housing and pattern holder assembly; 
     FIG. 18 is a vertical sectional view of the sleeve/yoke assembly of the fixture of FIG. 8; 
     FIG. 19 is a side elevational view of a locking knob of the sleeve/yoke assembly of FIG. 18; and 
     FIG. 20 is a front elevational view of the locking knob of FIG.  19 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For an understanding of this invention, reference is hereby made to FIG. 1 showing a typical installation of the projector  10  of this invention mounted on a supporting post P or other selected structure and directed toward the side of a building B or structure to project a visual pattern onto the side of the building to provide a remarkable visual image for viewers near the building B. The source of the patterns, preferably is a photographic slide or template that is interchangeable and mounted within the projector  10 . 
     The projection field of projector  10  is defined by the dashed lines expanding from the front of the projector  10  to the building B. The location of the projector  10  and the size of any internal mask is determined to provide either the entire sidewall of the building B or any selected area as the projection screen. The projector  10  can be as supplied with conventional 115 volt 60 cycle power to operate an internal conventional off-the-shelf lamp such as a MR 16 lamp with an internal metallized reflector. 
     The entire housing of the projector  10  is weather proof and designed for use at permanent indoor or outdoor locations. The only need to service the projector  10  will be to change the pattern and thereby change the visual image projected on the viewing surface and to periodically change the projection lamp. Normally, these will occur only after several months of use. 
     Now referring to FIG. 2 in combination with FIGS. 2A through 7, the projector  10  may be seen in FIG. 2 in a side elevation as including the inner housing or main body  11  which is preferably in the form of an end threaded and machined tube mounted in a sleeve  17  supported by a U-shaped bracket or yoke  12  which is readily secured by a pair of locking nuts  13  to sleeve  17 , the near side nut  13  only showing in FIGS. 2 and 2A. The yoke or mounting bracket  12  may be adjusted over approximately 350 degrees of rotation to accommodate a wide range of elevational angles for the projector  10  and limited only by the power supply cable for the projector  10 . The bracket  12  may also be pivoted over virtually a 360-degree range of azimuth adjustment when attached to a base or other support such as post P as illustrated in FIG.  1 . Sleeve  17  is secured to the outer surface of the inner housing  11  by a series of locking screws  18  which hold the inner housing  17  a selected cross hair angle for angular adjustment of the image projected on the building B or surface. This adjustment is independent of any focusing of the image and also independent of any azimuth or elevational adjustment of the projector  10 . 
     Secured to the main body  11 , at the rear, is the base or lamp house  14  with its cooling fins  15  and its rear electrical connection and seal  16  from which emerges the power cable  20 . At the opposite or front end of inner housing member  11  is the slide and lens assembly  30  and the front hood or shroud  22  containing the projection window  27  of tempered planar optical grade glass, best seen in FIG.  4 . 
     The projector housing is thermally isolated from the yoke and a through path for air circulation is illustrated in FIG.  5 . Note that there are only four lines LC and two points of contact between the outer corners of the spacers or side contact plates  26  of the inner housing  11  of FIGS. 3 and 7. 
     The front hood  22  is removable as is described below. In certain installations where there may be a possibility of loss or damage to this important part of projector  10 , a grooved housing  22 A is used, secured to the yoke  12  by a lanyard  28 . This is illustrated in FIG.  2 A. 
     Each of the foregoing components of the projector may be more clearly seen in the exploded view FIG.  3 . FIGS. 6 and 7 are of value for a further understanding of the inner housing and its mounting details. Referring to FIG. 3, the rear lamp housing  14  includes an O ring groove with its O ring  23  in place and a locking groove  24  into which a pair of locking screws  25  are driven through holes in the inner housing or main body  11  to hold the rear lamp assembly in sealed engagement with the rear of the main body  11 . As indicated above, the sleeve  17  is tubular and includes a pair of spacers or side contact plates  26  each which in turn is in engagement with the inner face of the yoke or mounting bracket  12 . This provides for a firm engagement of the projector  10  with its mounting bracket  12  and for secure locking with the locked nut  13  so that the projector  10  and the projected image do not move once the projector  10  is in place. 
     The lamp house  14  is mounted to the rear without interference with the slide or template mounts assembly, the optics  30  or the sealed front shroud and window  27 . 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  14  is accomplished by loosening one or more screws  25  and sliding the lamp house  14  rearward, removing the lamp (unshown and replacing it, followed by reinserting the lamp house  14  into main 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  14  in place. 
     In the form shown in FIGS. 4 and 5, the side contact plates  26  have been replaced by flats machined on the outer surface of the sleeve  17 . This version has the advantage of fewer parts but limits the frictional area of contact between the sleeve  17  and the yoke  12 . Therefore the embodiment of FIGS. 2,  6  and  7  is preferred. 
     In the embodiment of FIG. 2A, the front hood is grooved to receive a cable or lanyard  28  so that the hood  22 A is secured to the projector whenever it is removed to change the pattern or slide to alter the image projected. Otherwise, the projector of FIG. 2A is identical with that of FIG.  2  and thereby employs the same reference numerals to identify the same components as in FIG.  2 . 
     The optical elements of projector  10 , generally designated  30 , are in an assembly which rests within the interior of the inner housing or body  11  and is positioned by a slip fit engagement and O ring sealing the body  11 . The ring  21  secures the optical assembly in sealed engagement with the inner housing. The optical assembly  30  includes basically a fixed position convex tempered lens within the assembly  30  and a plano convex projection lens, unshown, contained within a focusable movable projection lens contained within its housing  31 . 
     The projection lens housing  31  includes a helical groove  32  on its outer surface which is engaged by locking screw  33  which is released to allow focusing of the optical system and then locked to retain housing  31  in its focused condition. 
     A photographic slide or template is mounted in a slide holder  61 , which is best seen in FIG.  14 A. 
     Now with an understanding of the various parts of this embodiment of this invention the features and advantages need to be reviewed. First, the fixture is waterproof not only protecting the electrical components from the dangers and damage from water intrusion but waterproof from the optical standpoint so that the image produced is protected from condensation, intruding water, or stains on optical components which could otherwise occur over a period of time. 
     The pattern as it appears on the projection surface may be rotated and corrected merely by loosening one screw and rotating the projector within its mount and retightening the screw. The waterproof seal is not broken in such operation. 
     The projector  10  may be relamped merely by removing the base  14  without affecting the focus or positioning of the projector. 
     A slide or template may be changed merely be removing the front housing, slipping out the old slide, slipping in a new one and reattaching the outer housing. Focus is not affected nor are any electrical elements affected. 
     The projector may be refocused by removing the front housing  22 , loosening screw  33 , manually adjusting the focus while observing the image, locking the focus with screw  33  and reattaching the front housing. 
     Elevation of the projector  10  may be changed by adjustment at the yoke  12  with locking knobs  13  released. Preferably, the locking knobs  13  are each secured by special set screws, which are virtually invisible to any casual viewer and releasable only with a special tool. The release of the set screws and knob  13  is the only way that the projector may be removed from the yoke  12 . A high degree of security for the fixtures is thereby provided. 
     An Allen wrench is needed for both embodiments. One requires it for lamp housing removal. Both require it for aiming lock. No other tools other than a screwdriver are needed for all of the adjustments to be made and all of the adjustments are self evident to service personnel for easy and rapid installation and servicing. 
     Alternate Embodiment 
     Now refer to FIGS. 8 through 20, showing an alternate embodiment designed for use with a higher wattage lamp, for example the PAR 20 lamp. In these and later figures, identical parts to the earlier figures will bear the same numerical designation and somewhat modified parts from the earlier embodiment but performing basically the same functions bear the same numerical designation but with a letter suffix. 
     In FIG. 8, a fixture  50  includes an inner housing  11 A carrying a base or rear lamp housing  14 A which is configured to receive a PAR 20 lamp to be powered through its rear seal  16  and power cord  20 . The base  14 A is secured and sealed to the inner housing by a locking ring  51  and O ring seal  52 . The lamp contained within the base  14 A may be exchanged by merely unthreading locking ring  51 , sliding the base  14 A back, removing the old lamp (unshown in the drawing), replacing the lamp with a new lamp and reassembling the base onto the inner housing  14 A which operation reestablishes the sealed relationship of the base  14 A to the inner housing  11 A. This can be done without affecting the orientation of the projector  10  or its focus. 
     The inner housing  11 A is also in sealed engagement with the front housing  22  with its window  27  by reason of the engaging threads of the front housing  22  and the inner housing  11 A and O ring seal  23 . 
     A removal of the front housing  22  allows access to both the optical subassemblies  53  for refocusing the projected image, if desired, and access to the slide or template assembly, best seen in FIGS. 13,  14  and  14 A for changing the image to be projected. Refocusing the optical system does not affect the slide or template mounting and changing the slide or template does not affect the focus. Reengaging the front housing returns the fixture to service in sealed condition. Each of these operations requires only the skills of regular lighting maintenance personnel. 
     Now referring specifically to FIGS. 9 through 11, the base  14 A with its cooling fins  15 , may be seen in its configuration designed for use with the standard 35 watt PAR 20 120 or 277 volt metal halide lamp which is mounted in a standard socket  54  which is held in the base  14 A by screw  55  or other means as shown in FIGS. 11 and 12. 
     The locking ring  51  with its internal threads  56  which engage the matching exterior threads of base  14 A and the integral retainer ring  57  which engages the inner housing  11 A may be seen in FIG.  12 . 
     FIG. 14 shows the inner housing  11 A assembled with a pattern holder assembly  60  which includes a pattern holder  61 , best seen in FIG. 14A, mounts a convex lens  62  of the optical system of the projector. The pattern holder assembly also includes a plate  63  and its forward extending tube  64 , which mount the projection lens mount  31  of FIGS. 8 and 17. 
     FIGS. 15 and 16 show the sleeve  17 A which secures the projector  50  to its yoke  12  while allowing the projector to be turned about its longitudinal axis or centerline CL in order to level the image on the building B or other surface upon which the image from the projector is desired to be displayed. Rotation of the projector  50  about its centerline axis CL is accomplished by merely loosening the single screw  18  appearing in FIG. 8 which passes through the opening  65  in sleeve  17 A and normally engages the inner housing  11 A in its ring groove  66 , best seen in FIG.  14 . Retightening screw  18  secures the projector  50  at the correct image orientation. 
     The details of the alternate embodiment pattern assembly holder  60 , the projection lens housing and the outer housing  22  may be best seen in FIG.  17 . The simple step of unscrewing the outer housing  22  exposes the projection lens housing  31  for focusing the image or exchanging the slide or template. Either operation may be performed without affecting the other. Refocusing is accomplished by slightly backing off the screw  33  which normally engages the root of the helical groove  66  in projection lens housing  31 , advancing or returning the projection lens to the desired focus position by observing the image on its display surface and then reengaging the screw  33 . Focusing can be performed with the outer housing removed since its lens  27  does not affect the focus of the image. 
     Merely sliding out the old slide template in its holder  61  to one side of the projector and inserting a new slide or template performs template exchange. After completion of either focusing or slide exchange, the outer housing is merely threaded back onto the front of the inner housing and the projector is ready to return to service. 
     Each of the objectives set forth above and each of the advantages of the embodiment of FIGS. 1-7 are achieved by the embodiment of FIGS. 8-20. 
     The foregoing descriptions constitute examples of the embodiments of this invention and are considered to be representative of the principles disclosed herein but are not intended to be limiting but illustrative. It is recognized that one skilled in the art with this teaching in hand could envision other embodiments, which appear somewhat different but do not depart from the spirit and principle of our invention as described herein. Therefore, the protection afforded by this application is considered to be defined by allowed claims obtained through the prosecution of this application and with the additional protection afforded by the Doctrine of Equivalents.