Abstract:
An accessory cartridge for removable reception in a specialized lighting fixture. A circular cartridge ring is provided with an internal lower flange, for supporting one or more flat, circular, disc-like accessory elements, such as filters. Retainer clips are positioned to engage at least the uppermost one of the disc-like accessory elements, such that one or more of the disc-like accessory elements may be easily installed within the cartridge ring and the entire series thereof automatically retained therein by engagement of at least the uppermost accessory element. The entire cartridge is designed to be bodily installed in or removed from the lighting fixture, to facilitate expeditious changing of accessory elements utilized with the lighting fixture. Preferentially, the lighting fixture is provided with a hingedly connected front barrel portion, which is constructed to receive and support the cartridge. The cartridge can be easily removed and/or installed when the barrel portion is hinged to an open position.

Description:
BACKGROUND OF THE INVENTION 
   Specialized lighting fixtures for such applications as theatrical lighting, museums, galleries, exhibits, etc. frequently involve the use of directed beam spotlight fixtures, typically mounted on a track, which can easily be adjusted as to location and as to direction of the beam for achieving desired results. In many cases, such specialized lighting fixtures employ accessory elements, such as color filters, conditioners, beam spreading lenses, etc. 
   In environments in which the lighting requirements change from time to time, for example, in theaters, museums, etc., it may be necessary to replace or exchange some or all of the accessory elements installed in a particular fixture. The present invention is directed to mechanisms for significantly expediting and simplifying the installation, removal and/or exchange of accessory elements in specialized lighting fixtures of the type described. Additionally, since the foregoing operations frequently have to be attended to by a workman standing on a ladder, there are safety issues involved in connection with the installation, removal and/or exchange of accessory elements, which can be dealt with beneficially by simplifying and expediting the tasks involved. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to a specialized lighting fixture useful in theatrical lighting and other specialized applications, both commercial and residential, involving the use of accessory elements which are expected to be changed from time to time for achieving various lighting effects. Pursuant to the invention, a special accessory cartridge is provided, which is removably installed within the lighting fixture, in the outlet portion thereof, and incorporates facilities for expeditiously securing one or a plurality of disc-like accessory elements, for achieving desired lighting effects. The basic arrangement is such that the accessory cartridge can be loaded with one or more accessory elements, as desired for the effects to be achieved, and the pre-loaded accessory cartridge simply inserted into the lighting fixture. The installation and/or removal of the accessory cartridge is quickly and easily accomplished in a manner that minimizes the hazard to a workman on a ladder, where such is required in order to reach the lighting fixture. 
   In accordance with one aspect of the invention, an advantageous form of accessory cartridge is provided which comprises a generally circular cartridge ring of an appropriate size and shape to receive one or a plurality of flat, disc-like accessory elements. In a typical case, from one to three accessory elements may be installed in the accessory cartridge before the cartridge is installed in the lighting fixture. The cartridge ring accordingly is provided with simple resilient means to accommodate the snap-in installation of accessory elements, one at a time, one above the other, with the entire “stack” of disc-like accessory elements being resiliently held in a fixed position relative to the accessory cartridge. 
   To particular advantage, and in accordance with one of the specific aspects of the invention, a unique and advantageous form of retainer clip is provided on the inner side wall of the cartridge ring for engagement with peripheral edges of the individual accessory elements. The retainer clip is uniquely shaped and contoured such that, with one or more such clips secured at one or more positions on the side wall of the cartridge ring, each accessory element is engaged and resiliently retained as it is installed in the cartridge ring, with at least the uppermost accessory element of a series thereof being engaged and resiliently retained and thus serving to retain any previously installed accessory element. 
   Preferably, the cartridge ring has an inwardly extending flange at the bottom, for supporting the accessory elements, and an outwardly extending flange at the top, for engagement with support areas of the lighting fixture. 
   In a most advantageous embodiment of the invention, the described accessory cartridge is incorporated in a lighting fixture having a tubular front barrel portion which can be separated or partially separated from the main body of the fixture for reception of the accessory cartridge. The front barrel portion is provided with an upwardly facing annular shoulder for seating the upper flange of the cartridge ring. Preferentially, the front barrel portion is hinged to the main body of the lighting fixture, such that the front barrel portion may be opened to receive the accessory cartridge while remaining attached to the body of the fixture. 
   For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of a preferred embodiment thereof and to the accompanying drawings. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a longitudinal cross sectional view of a specialized lighting fixture adapted to incorporate the accessory cartridge of the invention. 
       FIG. 2  is an exploded view illustrating the manner of assembly of various components into the opened front barrel portion of the lighting fixture. 
       FIG. 3  is an exploded perspective view of an accessory cartridge incorporating the features of the invention. 
       FIG. 4  is a top plan view of the accessory cartridge with one or more accessory elements received therein. 
       FIG. 5  is a longitudinal cross sectional view as taken generally on line  5 — 5  of  FIG. 4 . 
       FIG. 6  is an enlarged, fragmentary view of an encircled portion of  FIG. 5 , showing details thereof. 
       FIG. 7  is a front elevational view of a retainer clip element forming part of the accessory cartridge of the invention. 
       FIG. 8  is a top plan view of the retainer clip of  FIG. 7 . 
   

   DESCRIPTION OF PREFERRED EMBODIMENT 
   Referring now to the drawings, the reference numeral  10  designates generally a specialized lighting fixture including a mounting bracket  11 , a main body  12  and front barrel portion  13 . The mounting bracket  11  typically is secured to an elongated track (not shown) by way of a housing  14 , which can be secured to the track in any position along its length, all pursuant to well known concepts. The mounting bracket  11  is pivotally mounted at  15  for rotation about a vertical axis, and the body  12  of the fixture is pivotally mounted at  16  for rotation about a horizontal axis. 
   In the illustrated fixture, the body  12  may house a transformer  17  (for low voltage lighting) and mounts a suitable socket  18  for receiving an illuminating bulb  19 . 
   The outer housing  20  of the main body  12  is provided at its lower end with an outwardly extending annular flange  21  which supports an annular rotation ring  22 . The ring  22  is freely rotatable relative to the body housing  20 , but can be locked in a preset position by means of a locking element  23  and locking screw  24 . 
   In the illustrated light fixture, the front barrel  13  is secured to the rotation collar  22  by a hinge  25 , which allows the front barrel portion to be swung away from the body housing  20 , generally in the manner indicated in  FIG. 2  to, among other things, provide access for replacement of bulbs, accessory elements, etc. A locking screw  26  secures the front barrel in its “closed” position, and also provides a convenient engagement means for rotating the front barrel when it is released by loosening of the locking screw  24 . A cross baffle  27  is removably received in the front portion of the barrel  13 . The cross baffle consists of a pair of baffle plates  28 ,  29  arranged at 90 degrees and with their respective planes intersecting the principal longitudinal axis of the light beam. 
   The lighting fixture as thus far described is commercially available from Lighting Services Inc., Stony Point, N.Y., under their designation 238 Series Spotlights. For lights of this general type, it is conventional to employ various accessory elements, such as color filters, spreading lenses for controlling the shape of the spot, conditioners, screens, etc. The present invention is directed particularly to a novel accessory cartridge device that is easily installed in and removed from the lighting fixture, and which accommodates the installation therein of one or a plurality of disc-like accessory elements. The arrangement of the invention significantly simplifies and expedites the installation and replacement of such accessory elements. 
   In a preferred embodiment of the invention, the accessory cartridge comprises a cartridge ring  40  which includes a generally cylindrical side wall  41 , an outwardly extending annular flange  42  at the upper end thereof and an inwardly extending annular flange  43  at the lower end thereof. The diameter of the cylindrical wall  41  is slightly less than the diameter of the upper wall portion  44  of the front barrel of the lighting fixture. The upper flange  42  of the accessory cartridge is arranged to be supported on a shoulder  45  formed in an upper portion of the front barrel  13 . To advantage, opposed retaining springs  46  are fixed to the outside of the cylindrical wall  41  of the cartridge ring, and these springs are adapted to bear resiliently outward against the side wall  44  of the front barrel portion  13  such that, when the cartridge ring  40  is inserted into the front barrel portion  13 , it is temporarily held therein against accidental dislodgement by the friction of the springs  46 . 
   Pursuant to the invention, the inner diameter of the cartridge ring wall  41  is slightly greater than the outer diameter of a standard size disc-like accessory element, such as represented at  50 – 52  in the drawings. The typical accessory element may be comprised of a circular peripheral ring  53 , formed of metal and having a U-shaped cross sectional configuration, and a circular plate  54  formed of glass, plastic or the like and having the characteristics desired, such as color, UV filtration, focusing, conditioning, etc. In the illustrated form of the device, the cartridge ring  40  is designed to receive one to three accessory elements. However, pursuant to the principles of the invention, the cartridge ring may be designed to receive a greater number of accessory elements, should there be a need for such. 
   In accordance with the invention, the disc-like accessory elements  50 – 52  are releasably retained within the cartridge rings by means of specially contoured retainer clips  55 , shown individually in  FIGS. 7 and 8 , which are secured to the inside surface of the wall  41  of the cartridge ring. Preferably, and as reflected in  FIG. 3 , the retainer clips  55  are secured to the wall  41  by a pair of rivets  56 ,  57 , one of which ( 57  in this instance) is also utilized for mounting the retaining springs  46 . 
   The retainer clips  55  advantageously are formed of a flat, spring steel material of, for example, 0.015 in thickness, and are formed with a generally flat central panel portion  58  provided with openings  58   a  for the rivets  56 ,  57 , and provided on opposite sides with spring panels  59 ,  60  which extend at an angle to the plane of the central portion  58 . In the illustrated form of the device, in which the diameter of the cartridge ring  40  may be on the order of five inches, the side panels  59 ,  60  suitably are disposed at an angle of about 25 degrees relative to the plane of the central panel portion  58 . 
   As reflected in  FIG. 7 , the retainer clips advantageously can be formed of a generally circular metal piece, say of around 1.25 inches in diameter, preferably with upper portions thereof removed to form concave upper contours at  61 ,  62 , and formed with generously rounded corners  63 ,  64  at a level slightly above one-half the height of the element  55 . For example, approximately 0.75 inch above the bottom in a part having an overall height of about 1.25 inches. Preferentially, the retainer clips are mounted with their lower edges contacting or closely adjacent the bottom flange  43  of the cartridge ring  41 . 
   Pursuant to the invention, the contoured edges of the retainer clips  55  function to automatically assure that the last accessory element  50 – 52  installed in the cartridge ring will be securely gripped by outer edge portions  65 ,  66  of the opposed retainer clips. Thus, when inserting a single accessory cartridge  50 , the accessory element is placed in the upper portion of the cartridge ring until it rests upon the upper corner areas  63 ,  64  of the retainer clips. The accessory element can then be pressed downward, deflecting the side panels  59 ,  60  of the retainer clips, until the accessory element rests upon the lower flange  43  of the cartridge ring. 
   As will be understood, the edges  65 ,  66  of the retainer clips will be spaced a greater distance radially inward from the cylindrical wall  41  at the widest portions of the retainer clips and will be spaced progressively lesser distances from the wall  41  opposite the lower portions of the retainer clip. The normal clearance space between the side edge extremities of the accessory elements and the inner surface of the side wall  41  is such that, when the accessory element  50  is in its lowest position, seated on the flange  43  of the cartridge ring, lower portions of the retainer clip edges  65 ,  66  will bear against upper corner portions  70  ( FIG. 6 ) of the accessory element to retain it snugly in the accessory cartridge. 
   If a second accessory element  51  is to be inserted into the cartridge, it is inserted in the same manner as the first element  51 , deflecting the side panels  59 ,  60  of the retainer clip as the accessory element is pressed downwardly and seated directly atop the first-loaded accessory element  50 . In that position, upper corner portions  71  of the peripheral ring surrounding the accessory element  51  are engaged by portions of the panel edges  65 ,  66  higher up along the retainer clips  55 . Inasmuch as the edge portions of the retainer clips engaged with the second accessory element  51  tend to be spaced farther inward from the wall  41  than edge portions below, the panels  59 ,  60  will be resiliently displaced radially outward somewhat by the second accessory element  51  when it is finally seated against the lower element  50 . This may relieve the resilient pressure of the retainer clips against the lower accessory element  50 , either partly or entirely. However, since the second level accessory  51  is now firmly gripped by the retainer clips, the “stack” of the two accessory elements is firmly held in place in the accessory cartridge. 
   Similarly, if a third accessory element  52  is to be installed, it is pressed into the accessory cartridge until it seats directly on top of the second element  51 , and upper corner portions  72  of the third accessory element  52  are then contacted by upper portions of the panel edges  65 ,  66 . To the extent that retaining pressure against the lower accessory elements is partially or entirely relieved by displacement of the panels  59 ,  60  by the uppermost accessory element  52 , the entire stack remains firmly installed in the cartridge by the gripping action on the uppermost accessory element  52 , as will be understood. 
   Pursuant to the invention, the accessory cartridge can be conveniently loaded with one or more desired accessory elements while removed from and remote from the lighting fixture. After the cartridge has been properly loaded, the front barrel portion  13  of the lighting fixture can be pivoted to an open position (if closed) and a cartridge ring  40  inserted into the upper portion of the front barrel until the upper flange  42  of the cartridge ring is seated on the shoulder  45  of the front barrel portion. The accessory cartridge will tend to be self-retaining within the front barrel during the installation process, by reason of the friction of the springs  46  mounted on the opposite exterior walls of the cartridge ring, acting against the barrel wall  44 . After the cartridge ring is installed in position, the front barrel portion  13  is closed and locked. 
   Reloading of the cartridge ring, as may be desired from time to time for different lighting effects, is easily accomplished by simply opening the front portion of the lighting fixture, bodily removing the accessory cartridge, and reloading it with the desired new accessories. The cartridge is then quickly and efficiently reinstalled in the lighting fixture as previously indicated. 
   With the device of the invention, not only is the re-accessorizing operation greatly simplified and expedited, but it is also made a great deal safer for the servicing personnel, in cases where access to the lighting fixture requires the workman to stand on a ladder. Additionally, when necessary to access the lighting fixture for re-lamping, the front barrel portion can be simply opened up to provide access to the bulb  19 , without affecting any accessory discs previously installed and without having to be concerned with their accidental dislodgement from the lighting fixture. 
   It should be understood of course that the specific embodiment of the invention herein illustrated and described is intended to be representative only, as certain variations may be made therein without departing from the clear teachings of the disclosure. In addition, specific directional references such as up, down, bottom, top, etc. are not limiting and are referenced only to the orientation of the illustrated views. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.