Abstract:
An effects wheel assembly for a light fixture, in particular a stage light fixture, suitable to generate a light beam, has a supporting device which rotates about a first axis; and an effects wheel having a hub, which extends about a second axis, and an effects portion, which extends about the hub and is suitable to generate optical effects when intercepting the light beam; the supporting device and the effects wheel being selectively connectable to each other by means of jaws elastically operated to clamp the effects wheel when the hub is inserted between the jaws.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. Nationalization of PCT International Application No. PCT/IB2009/005324 filed 22 Apr. 2009, entitled “EFFECTS WHEEL ASSEMBLY FOR A LIGHT FIXTURE, IN PARTICULAR A STAGE LIGHT FIXTURE,” which claims priority to Italian Patent Application No. MI2008A000741 filed 23 Apr. 2008, the entireties of both of the foregoing applications are incorporated herein by reference. 
     TECHNICAL FIELD 
     Embodiments of the present invention relate to an effects wheel assembly for a light fixture, in particular a stage light fixture suitable to generate a light beam. 
     BACKGROUND ART 
     Specifically, the effects wheel assembly comprises a supporting device which rotates about a first axis; an effects wheel having a hub, which extends about a second axis, and an effects portion, which extends about the hub and is suitable to generate optical effects when intercepting the light beam; the supporting device and the effects wheel being selectively connectable to each other. 
     The definition “effects wheel” comprises, for the purposes of the present description, both an effects wheel having an effects portion defined by a metal annular plate suitable to accommodate gobos, and an effects wheel having an effects portion defined by a glass disc. 
     The term “gobo” defines a metal disc, typically made of stainless steel or glass, in which a motif or shape suitable to shape the light beam is obtained. Each gobo is generally coupled, in a releasable manner, in a respective seat of the metal annular plate. 
     Generally, the effects wheel is connected to the supporting device by a screw. This fastening mode does not allow the effects wheel to be easily coupled with the supporting device and compromises the interchangeability thereof. 
     In order to avoid this drawback, effects wheel assemblies of the above-described type, which include a magnetic fastening device between the effects wheel and the supporting device, have been developed. The mentioned effects wheel assemblies are, inter alia, disclosed by U.S. Pat. Nos. 6,971,770 B2 and 7,222,997 B2, which is the continuation in part of U.S. Pat. No. 6,971,770 B2. 
     In accordance with the aforementioned U.S. Pat. No. 6,971,770 B2, the connection between the supporting device and the effects wheel is obtained by means of a washer, which is defined by a permanent magnet, is fixed to the effects wheel, and is fastenable to the supporting device, which is made of ferromagnetic material. 
     In accordance with the aforesaid U.S. Pat. No. 7,222,997 B2, the connection between the supporting device and the effects wheel is obtained by means of a washer, which is defined by a permanent magnet, is fixed to the supporting device, and is fastenable to the effects wheel, which has a hub made of ferromagnetic material. 
     U.S. Pat. No. 7,222,997 B2 also includes the solution in which both the supporting device and the effects wheel comprise respective washers consisting of permanent magnets. 
     The clamping by means of magnetic force is not sufficient to ensure the correct alignment between the first axis of the supporting device and the second axis of the effects wheel. For this reason, the effects wheel assemblies defined above comprise respective centering means, each of which is defined by a hole and a pin which may be reciprocally coupled and respectively staggered with respect to the first and second axes so as to transmit a torque between the supporting device and the effects wheel. 
     The effects wheel assemblies identified above have proven to be effective; however, coupling the effects wheel with the supporting device is difficult because the space inside the light fixture is confined and does not allow the operator who couples the effects wheel with the supporting device to see the coupling area. Therefore, centering is made by trial and error in sequence, and also provided that the magnetic force inadvertently attracts the effects wheel when the operator approaches the hub to the effect wheel within a given distance. 
     SUMMARY 
     One or more embodiments of the present invention provide an effects wheel assembly for a light fixture which generally facilitates the replacement of the effects wheel. 
     One or more embodiments of the present invention provide an effects wheel which facilities the step of coupling the effects wheel with the supporting device. 
     According to an embodiment of the present invention, an effects wheel assembly for a light fixture, in particular for a stage light fixture, is disclosed, which comprises a supporting device which rotates about a first axis; and an effects wheel having a hub that extends about a second axis, and an effects portion that extends about the hub and is suitable to generate optical effects when intercepting the light beam. The supporting device and the effects wheel are selectively connectable to each other. The effects wheel assembly is characterized in that the supporting device comprises first and second jaws elastically operated to releasably clamp the effects wheel when the hub is inserted between the first and second jaws. 
     One or more embodiments of the present invention further concern a stage light fixture. 
     In accordance with an embodiment of the present invention, a light fixture, in particular a stage light fixture, suitable to generate a light beam is provided. The light fixture comprises an effects wheel assembly provided with an effects wheel having a hub that extends about a first axis and an effects portion that extends about the hub and is suitable to generate optical effects when intercepting the light beam; and a supporting device, which rotates about a second given axis and is selectively connectable to the effects wheel. The light fixture is characterized in that the supporting device comprises first and second jaws which may be elastically operated to releasably clamp the effects wheel when the hub is inserted between the jaws with the first axis aligned to the second axis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details, features and advantages of the invention will be more apparent from the description of the following non-limitative embodiments, with reference to the accompanying drawings, in which: 
         FIG. 1  is a diagrammatic side elevation view, with parts removed for clarity, of a stage light fixture comprising an effects wheel made according to an embodiment of the present invention; 
         FIG. 2  is a side elevation section view, on enlarged scale and with parts removed for clarity, of a component of the effects wheel assembly in  FIG. 1 ; 
         FIG. 3  is a side elevation section view, on enlarged scale and with parts removed for clarity, of the effects wheel assembly in  FIG. 1 ; 
         FIG. 4  is an exploded view, on enlarged scale and with parts removed for clarity, of the effects wheel assembly in  FIG. 1 ; 
         FIG. 5  is a front elevation view, with parts removed for clarity, of a detail of the component in  FIG. 2 ; 
         FIG. 6  is a side elevation section view, with parts removed for clarity, of an effects wheel assembly in accordance with a second embodiment of the present invention; 
         FIG. 7  is a front elevation view, with parts removed for clarity, of a detail of the effects wheel assembly in  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 1 , numeral  1  indicates as a whole a stage light fixture comprising a casing  2 , a frame  3 , a light source  4  for originating a light beam L, a spotlight  5  for orienting the light beam L, and a lens assembly  6  for obtaining a zoom effect. 
     The definition of stage light fixture includes both fixed-head light fixtures and jointed-head light fixtures. 
     In general, stage light fixture  1  comprises a plurality of components (most of which not shown) arranged between the light source  4  and the lens assembly  6 . Such components serve the function of generating optical effects, and these include an effects wheel assembly  7 , which is selectively capable of intercepting the light beam L. The other components, including the color disc, the dimmer, the frame, the rotating gobos assembly (not shown in the accompanying drawings) and the other fixtures of known type, also not shown in the accompanying drawings, are arranged inside the casing  3  and considerably reduce the available space inside the light fixture  1 . With this regard, it is worth reminding that market needs impose to make small, manageable stage light fixtures with, at the same time, a plurality of components which allow to make a plurality of optical effects. Furthermore, according to a variant not shown in the accompanying drawings, the stage light fixture  1  may comprise more than one effects wheel assembly  7 , so as to be able to combine the optical effects of the two effects wheel assemblies  7 . 
     The effects wheel assembly  7  is supported by an arm  8  connected to the frame  3  and a shaft  9 , which rotates with respect to the arm  8  and is operated by a motor  10 . 
     The effects wheel assembly  7  comprises a supporting device  11 , which is fixed to the shaft  9 ; and an effects wheel  12 , which is selectively fastenable to the supporting device  11 . 
     With reference to  FIG. 2 , the supporting device  11  extends about an axis A 1  and comprises a sleeve  13  suitable to accommodate the shaft  9  ( FIG. 1 ); a jaw  14  integral with the sleeve; a jaw  15  coupled so as to slide along axis A 1 ; an abutting element  16  fixed to the jaw  14 ; and a spring  17  suitable to bias jaw  15  towards jaw  14 . 
     The sleeve  13  has two holes  18  and  19 : the hole  18  is perpendicular to axis A 1  and suitable to accommodate a dowel (not shown in the accompanying drawings) in order to fix sleeve  13  to shaft  9  ( FIG. 1 ), while the hole  19  is coaxial to the sleeve  13  and suitable to fix the abutting element  16 . 
     The jaw  14  is disc-shaped and integral with the sleeve  13 . On the side opposite to the sleeve  13 , the jaw  14  has a cylindrical seat  20  with axis A 1  and a plurality of cavities  21  distributed along a face  22  of the jaw  14  and along a primitive of axis A 1  and about axis A 1 . In the case illustrated in  FIG. 5 , the cavities  21  are uniformly distributed about axis A 1 , are cone-shaped and are sixteen in number. In other words, cavities  21  are spaced out by an angle of 22.5°. 
     With reference to  FIG. 2 , the jaw  15  is annular disc-shaped with a recessed central portion. In particular, the jaw  15  comprises a central annular disc  23  joined to a cylinder  24 , which is joined to an annular disc  25 , which lays on a plane parallel to and staggered from the laying plane of the annular disc  23  and has a face  26  facing the face  22 . 
     The jaw  15  is coupled with the jaw  14  so as to slide along axis A 1 . In particular, the cylinder  24  is coupled so as to slide along axis A 1  in the seat  20 , so that the face  26  is held at a given distance from the face  22  when the jaw  15  abuts against the jaw  14 . 
     The faces  22  and  26  are joined by chamfers to the external edge of the respective jaws  14  and  15  to facilitate the insertion of the effects wheel  12 . 
     The abutting element  16  is essentially a screw which has in sequence, from left to right, a threaded shank  27 , a spacer  28  coaxial to the threaded shank and a flared head  29 . The abutting element  16  is screwed into the treaded hole  19  when jaw  15  and spring  17  are arranged between the jaw  14  and the abutting element  16 , in particular the head  29  of the abutting element  16 . 
     With reference to  FIG. 4 , the effects wheel  12  comprises a hub  30 , which extends about an axis A 2  and an effects portion  31 , which extends about the hub  30 . 
     In the case in  FIG. 4 , the effects wheel  12  comprises a metal annular plate  32  having a plurality of seats  33  for accommodating the gobos  34  at the effects area, and a spring  35  for maintaining the gobos  34  in the corresponding seats  33 . The plate  32  has a slot  36  which extends through the effects portion  31  and through the hub  30 : the slot  36  is particularly wide in the effects portion so as to allow the light beam  1  to pass in that given area ( FIG. 1 ), while it is particularly narrow at the hub  30 . In particular, the slot  36  is delimited by an edge  37 , which in the area of the hub  30  substantially corresponds to the diameter of the cylinder  24 , which defines, as better illustrated in  FIG. 3 , an abutting and centering element for the effects wheel  12 . 
     With reference to  FIG. 4 , the effects wheel comprises three protrusions  38  arranged at 90° from one another at the hub  30 . Alternatively, a single protrusion  38  or a number of protrusions distributed about axis A 1  with a distribution pitch equal to an integer multiple of 22.5° would be sufficient, so that each protrusion  38  may be accommodated in a respective cavity  21 , as shown in  FIG. 3 . The high number of cavities  21  ( FIG. 5 ) avoids the supporting device  11  from being rotated with respect to the effects wheel  12  for achieve the coupling. 
     With reference to  FIG. 3 , the effects wheel  12  is arranged between the two jaws and with the axis A 2  thereof aligned with the axis A 1  of the supporting device  11 . Furthermore, the protrusions  38  are engaged in respective cavities  21  and, in the case shown, are substantially bosses made by drawing in the metal annular plate  32  at the hub  30 . 
     In  FIG. 6 , numeral  39  identifies an effects wheel assembly which comprises a supporting device  11  identical to that described with reference to the previously described embodiment, and an effects wheel  40 , which comprises a hub  41  extending about an axis A 2  and an effects portion  42  extending about the hub  41 . 
     In the case in  FIG. 6 , the effects portion  42  is defined by a glass disc  43  having a varying thickness to deform the light beam L ( FIG. 1 ) clamped between two flanges  44  and  45 , which define the hub  41 . The flange  45  is U-folded and has a plate  46  along which a slot  47  is obtained being provided with an edge  48  and protrusions  49 . In this case, the plate  46  lays on a plane parallel to and staggered from the laying plane of the effects portion  42 . The operation of the glass effects wheel  40  does not include the possibility of making a slot along the effects portion  42 . 
     The inserting and releasing modes of the effects wheel  40  are described with reference to the effects wheel  12 . 
     It is finally apparent that changes and variations may be made to the effects wheel assemblies  7  and  39  described herein without departing from the scope of the appended claims.