Abstract:
An articulating accessory cartridge for use in theatrical and commercial lighting fixtures in which optical accessories are utilized. The cartridge includes an outer member removably insertable in the fixture and an inner member telescopically retained in the outer member. One or several optical accessories can be removably received and retained in the inner member in an axial stack, depending upon effects desired. The inner cartridge member is telescopically extended before the cartridge is mounted on the fixture. As the cartridge is inserted, the uppermost accessory engages the end of a reflector associated with a light source in the fixture. Continued insertion of the cartridge results in telescopic retraction of the inner cartridge member, depending upon the number of accessories in the stack, until the outer cartridge member is fully seated. The accessories are held against the end of the reflector for optimal efficiency of the lighting and lighting effects.

Description:
FIELD OF THE INVENTION 
     The invention relates to the field of specialty lighting and more particularly to specialty lighting fixtures useful for theater and commercial lighting applications, where the fixtures frequently incorporate accessory elements such as distributing lenses, color discs and the like, and especially where there may be a need or desire to change the accessories from time to time. 
     BACKGROUND OF THE INVENTION 
     Specialized lighting fixtures, such as for theaters, museums, galleries, exhibits, etc. frequently employ accessory elements, such as color filters, conditioners, beam spreading or concentrating lenses, and the like to achieve desired lighting effects. In many such circumstances, it is necessary or desirable to change the accessories from time to time to accommodate changes in the lighting requirements. As set forth in a related U.S. Pat. No. 6,942,368, to Kenneth M. Kane et al, it is advantageous to utilize a removable cartridge to hold the desired accessories. This allows the accessories to be installed in a cartridge in the proper order, at a work bench or other convenient location, after which the cartridge can be quickly and easily inserted into the lighting fixture. This minimizes the time and effort required of a service man while working high on a ladder. 
     Inasmuch as a given lighting fixture may typically utilize from one to three accessories, and occasionally none, there was a need to be able to optimally position the accessories with respect to the light source, in order to enhance the efficiency of the lighting and the effectiveness of the accessories. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an improved form of accessory cartridge, which can be replaceably installed in a lighting fixture and which automatically results in a desired positioning of the accessories relative to the light source, regardless of the number of accessories installed in the cartridge. To this end, the accessory cartridge of the invention comprises two telescopically joined cartridge members. An outer member is of a size and shape to be received in a fixed position at the open end of the lighting fixture. An inner member is received within the outer member and is telescopically movable with respect thereto over a fixed range of axial movement. Detent arrangements are provided to retain the two members in any position with the intended axial range, unless intentionally displaced. 
     In the preferred and illustrated embodiment of the invention, the inner cartridge member is of a size and shape to receive one or more, usually but not necessarily up to a maximum of three, accessory elements. Typically, the accessory elements are flat discs which, if more than one is used, are arranged in an axial stack, one on top of the next. After the cartridge is loaded with the desired accessories, the inner and outer members are moved into an axially extended configuration in which the accessories are elevated in relation to the bottom of the cartridge. 
     When the loaded cartridge is partially inserted into the open end of the fixture, the uppermost accessory disc engages a fixed stop element within the fixture housing. Thereafter, as the outer cartridge member is moved deeper into the housing, the inner cartridge member is held by the stop element and retains a desired predetermined position relative to the light source while the outer cartridge member is being fully seated in the fixture. To advantage, the stop element is the open end of a reflector which surrounds the light source and directs its light in a desired manner from the fixture housing. 
     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 of the invention and to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view, partly in section of a lighting fixture and articulating accessory cartridge according to the invention. 
         FIG. 2  is a perspective view, partly in section, showing the lighting fixture and accessory cartridge of  FIG. 1  in assembled relation. 
         FIG. 3  is a longitudinal cross sectional view of the assembly of  FIG. 2 . 
         FIG. 4  is a top view of the accessory cartridge of the invention. 
         FIG. 5  is a cross sectional view as taken along line  5 - 5  of  FIG. 4 . 
         FIG. 6  is an enlarged, fragmentary cross sectional view as taken along line  6 - 6  of  FIG. 4 . 
         FIG. 7  is a perspective view from below of an inner member of the accessory cartridge of the invention. 
         FIG. 8  is a top view of the cartridge member of  FIG. 7 . 
         FIG. 9  is a cross sectional view as taken along line  9 - 9  of  FIG. 8 . 
         FIG. 10  is an enlarged fragmentary view of a portion of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings, and initially to  FIGS. 1-3  thereof, the reference numeral  20  designates generally a lighting fixture of a type used frequently in commercial and theatrical lighting. The fixture includes a housing  21 , a light source module  22  and a power supply  23  for the light source. A suitable, but not limiting, light source module may be an XSM 80 LED module by Xicato, Inc. of San Jose, Calif. Such a module is illustrated in U.S. Pat. No. 7,988,336, the content of which is incorporated herein by reference. A reflector  24  is associated with the light source module and extends axially downward therefrom. In this respect, it will be understood that the lighting fixture  20  may be oriented in any direction, including upward, downward and at any angle to the vertical. Accordingly, directional references herein, and in the claims, to upward, downward and the like are used only for convenience and with respect to the illustrated fixture, which is oriented in a downward direction. Desirably, the reflector  24  is interchangeable in order to provide different degrees of concentration or dispersion of the light beam from the source  22 . In the illustrated arrangement, the upper end of the reflector is provided with a plurality of lateral tabs  25  which are received in recesses  26  in the light source module, after which the reflector is rotated about its axis to engage the tabs  25  with locking elements  27  of the light source module  22 . 
     Pursuant to the invention, a novel form of accessory cartridge  30  is provided, which is insertable into the open lower end  31  of the fixture housing  21 , for retaining on or more accessory discs  32 . In the illustrated example, the cartridge  30  has the capacity to receive up to three accessory discs (or none, if desired). The cartridge  30  is comprised of an outer member  33 , which is adapted to be received and retained in the open end of the fixture housing  21 , and an inner member  34 , which is movably retained within the outer member for a limited extent of telescopic movement. 
     In the illustrated form of the invention the outer cartridge member  33  includes a lower portion  35  and an upper portion  36 . The lower portion  35  is of cylindrical form and is provided with a flange  37  at its lower end. As shown in  FIG. 3 , the lower portion  35  is adapted to be received closely within the end of the fixture housing  21 , with the flange  37  seated against the bottom of the housing to fix the position of the cartridge with respect to the light source module  22 . The upper portion  36  of the outer cartridge member is of smaller diameter than the lower portion  35  and spaced somewhat above the lower portion. The upper portion  36  is connected with the lower portion by a plurality of circumferentially spaced apart ribs  38 ,  38   a . The arrangement and spacing of the upper and lower portions of the outer member provide, among other things, clearance for the flow of air through the cartridge for cooling of the light source module  22  and its power supply  23 . 
     Suitable means are provided for retaining the outer cartridge member  33  within the fixture housing  21  after installation. In the illustrated embodiment, such means can be in the form of a plurality of retainer springs  39 , which are riveted or otherwise secured to the upper portion  36  of the cartridge member  33  and extend outward and downward therefrom as shown in  FIGS. 1-3 . When the cartridge is inserted into the housing  21 , the retainer springs are compressed inwardly to resist downward movement of the cartridge relative to the housing. For intentional cartridge removal, the outer edge margins of the flange  37  extend slightly beyond the outer surface of the housing  21 , as shown in  FIG. 3 , enabling the cartridge to be easily gripped by a hand for removal from the housing. 
     In the illustrated embodiment of the invention, the inner cartridge member  34  is of generally cylindrical form and has an outer diameter very slightly smaller than the inside diameter of the upper portion  36  of the outer member  33 . The arrangement is such that the inner member  34  can be telescopically adjusted axially with respect to the outer member. The inner cartridge member  34  is comprised of upper and lower portions  40 ,  41  which are connected in fixed relation by circumferentially separated spacer elements  42 . In the illustrated arrangement, there are three such spacer elements  42  which are widely separated by openings  43  to accommodate the circulation of air within the fixture. 
     Each of the spacer elements  42  is provided externally with one or more projections  44 , which extend radially outward and are adapted to engage the bottom edge  45  of the upper portion  36  of the outer cartridge member. This serves to define an upper limit of extending telescopic movement of the inner cartridge member  34  relative to the outer member. A lower limit of retracting telescopic movement is provided by means of upward extensions  46 , which are preferably although not necessarily aligned with the spacer elements  42 . At their upper extremities, the upward extensions are formed with flanges  47  extending radially outward and overhanging the upper edge  48  of the upper portion  36  of the outer cartridge member  33 . When the inner cartridge member  34  is moved telescopically downward toward a retracted position, the flanges  47  will engage the upper edge  48  when the retracted limit position is reached. The upward extensions  46  have sufficient flexibility to be displaced radially inward when the inner cartridge member  34  is initially assembled with the outer member  33 . In this respect, the upper surfaces of the flanges are angled such that the extensions  46  tend to be cammed inwardly during the initial assembly of the two cartridge members  33 ,  34 . 
     The lower portion  41  of the inner cartridge member is formed with an inwardly projecting flange  49  arranged to support outer edge portions of an accessory disc  32  ( FIG. 3 ). The internal diameter of the inner cartridge member  34  is such that it can closely but loosely receive one or more of the accessory discs, stacked one on top of the other. Typically, but not necessarily, the accessory cartridge is designed to receive up to three such accessory discs. Advantageously, the accessory discs  32  are retained in the cartridge member  34  by integral, flexible retaining tongues  50  formed in the spacer elements  42  by means of U-shaped slots  51  therein. The retaining tongues are provided on the inside with axially extending ribs  52 , which project inwardly from the cylindrical contours of the spacer elements. The inner surfaces of the ribs  52  lie on a diameter which is slightly smaller than the diameter of the accessory discs  32 , and the upper ends  53  of the ribs  52  are tapered into the side walls of the spacers, as illustrated best in  FIG. 10 , to facilitate downward insertion of the accessory discs into the cartridge member  34 . 
     When an accessory disc is inserted into the inner cartridge member  34 , it is initially engaged by the tapered upper end portions  53  of the ribs  52  and must be pushed downwardly with enough pressure to displace the tongues  51  and ribs  52  radially outward, as shown in  FIG. 3 . The slight outward angle of the displaced ribs  52  imparts a slight downward force component on the disc  32  to retain it is position against the flange  49 . 
       FIG. 3  illustrates the cartridge with a single accessory disc installed. If a second disc (not shown) is inserted on top of the first, the second disc will displace the ribs  52  slightly farther outward, after which the ribs will apply retaining pressure against the upper disc. A similar action results when a third disc (not shown) is inserted on top of the second. In each case, the deflection of the tongues  51  and ribs  52  causes the ribs to press inward and downward on the top most disc to retain the entire stack in the cartridge. 
     When accessory discs are loaded into the cartridge, the initial loading is followed by telescopically extending the inner cartridge member  34  with respect to the outer cartridge member  33 , preferably until the projections  44  engage the edge  45  of the outer cartridge member  33 , setting the limit position of the inner member  34  in an extending direction. 
     Upon a partial insertion of a loaded cartridge into the end of the fixture housing  21 , the uppermost accessory disc  32  of a stack (whether a single disc or a stack or two or three) is engaged by the lower end edge  54  of the reflector  24 . The accessory discs, and the inner cartridge member  34  are thus stopped and prevented from moving as the outer cartridge member  33  continues to be inserted upwardly into the housing, until the flange  37  engages the end of the housing. After the insertion, the outer cartridge member is held in position in the fixture housing  21  by the retainer springs  39 , and the disc stack is held in fixed position against the end of the reflector. Placement of the accessory discs  32  a known, fixed distance from the light source  22  assures optimum efficiencies from the light source and also uniform and optimized output from the accessories. 
     In the illustration of  FIG. 3 , with only one accessory disc  32  carried in the inner cartridge member  34 , the inner cartridge member is displaced slightly downward relative to the outer member  33 , as is indicated by the position of the projections  44  in  FIG. 3 . If three accessory discs are loaded into the inner member it would be displaced further downward, by the thickness of the two additional discs, such that the lowermost disc of the stack will be located at a level adjacent to the level of the bottom edge of the outer cartridge member  33 . In cases were no accessory discs are loaded, the inner cartridge member would remain in its fully extended position after installation of the cartridge into the fixture housing  21 , with the projections  44  against the edge  45 , in which position the flange  49  is entirely out of the path of light emanating from the reflector  24 . In all cases in which at least one disc is present, the uppermost disc will be held in contact with the end of the reflector  24 . 
     In order to hold the inner cartridge member  34  in whatever position it assumes after insertion of the outer cartridge member  33  into the fixture housing, a detent arrangement is provided which will retain the inner member in position with respect to the outer member, unless intentionally changed. To this end, the outer surface of upper portion  40  on the inner cartridge member is formed with a plurality of circumferential detent grooves  55  engageable by detent projections  56  extending inwardly from upper and/or lower sets of flexible tongues  57 ,  58  formed in the wall of the upper portion  36  of the outer cartridge member  33  ( FIGS. 5 ,  6 ). When the inner member  34  is in or near a fully extended position, the projections  56  of the upper tongues  57  will grip the grooves  55 , while the projections  56  of the lower tongues will grip the grooves when the inner cartridge is in a lower or more retracted telescopic position. Accordingly, upon installation of the cartridge in the end of the housing  21 , and resulting displacement of the inner cartridge member by contact between an upper accessory disc and the reflector  24 , the inner cartridge member will be retained in its displaced position, with the uppermost disc against the bottom edge  54  of the reflector. 
     The new articulating accessory cartridge of the invention makes it easy and reliable to position the accessory discs, regardless of number thereof, in an optimum relation to the light source, such that optimum and reproducible lighting effects may be achieved. Changing of accessory discs in the cartridge is a simple matter of pushing them upwardly out of the inner cartridge member  34 , for removal, and downwardly for loading. The uppermost disc is engaged by the retaining tongues  50  to retain all of the installed accessory discs in a tight stack against the lower flange  49 , and installation of the loaded cartridge into a fixture housing automatically telescopically repositions the inner cartridge  34  member as necessary to locate the accessories mounted therein in optimal relation to the light source. 
     It should be understood, or course that the particular embodiments of the invention herein illustrated and described are intended to be representative of the invention but not limiting thereof. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.