Patent Publication Number: US-7901114-B2

Title: Lighting fixture iris positioning apparatus

Description:
The present application claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 60/866,746, filed Nov. 21, 2006. 
    
    
     BACKGROUND 
     Typically theatrical lighting fixtures are intended to be fixed in position. However because of their compact size, often a theatrical lighting fixture is used as an improvised spotlight, or follow-spot. Theatrical lighting fixtures are provided with a number of controls for varying the intensity of light output and the size of the light beam. Theatrical lighting fixtures are mounted on a yoke, which allows an operator to direct the light beam up or down and from side to side when used as a spotlight. Theatrical lighting fixtures also have an iris which may be used to increase or decrease the size of the diameter of the light beam. Additionally, theatrical lighting fixtures may have a douser for varying the intensity of the light beam or blocking the light beam entirely. Often, an operator must control these several attributes of a light beam at the same time. 
     Among these attributes, an operator may be required to vary the position of the light beam, vary the intensity of the light beam, and the size of the light beam simultaneously. Currently, when a theatrical lighting fixture is used as a spotlight, the operator must maintain the position of the light with one hand, leaving the other hand to operate both the iris and the douser, among other functions. 
     When the lighting fixture is used in a side-lighting capacity, the lighting fixture is operated from the side of the stage, typically above and close to the edge of the proscenium opening. It is possible that in operation, the light will swing through an arc of 70 degrees, while shifting its throw, the distance to the illuminated subject, from approximately 20 to 60 feet. Adjusting the iris continuously and smoothly through this swing is difficult, and may be additionally challenging if there are obstructions that prevent reaching continuously. Conventional theatrical lighting equipment, and in particular the Source Four manufactured by ETC and other ellipsoidal reflector type lighting fixtures equipped with irises, are often used in this application as compact spotlights owing to their small size, allowing the lighting fixture and operator to be placed in a very small space on the proscenium of a stage set. As there are many other devices that also have to be placed on the proscenium of the stage set, space is at a premium, and many obstructions are present. 
     It is usually left to the operator to devise some method of marking the settings of the iris and douser, either by memory or with small pieces of tape or wire, to form a tactile indicator, as the iris is not usually in the operator&#39;s line of sight while operating the light. 
     Conventional theatrical lighting fixtures are also prone to light leaks, which are made more apparent when the lighting fixture is used as a spotlight. This is because lighting fixtures of this type are generally not designed to function as a spotlight, and therefore light leakage is not likely a primary design consideration. The iris slot must not be obstructed in order to allow unencumbered movement of the iris handle, but light reflects off the internal components of the lighting fixture, leading to light leaks thru the iris slot. When used as intended, the lighting fixture is equipped with a metal cover which is slid over the iris slot. This serves to stop light leafs as well as lock, through friction, the iris. Locking the iris is not always a desirable feature in a spotlight. 
     Light leakage from a lighting fixture may be manifested by the projection of errant rays of light to on the set in unintended and distracting patterns. The iris slot, thru which the iris handle moves, is a particularly difficult source of light leaks, as the slot cannot be covered with any of the traditional tapes or foils available to the industry, since the iris handle has to be free to move unencumbered through this slot, and additionally, the iris handle must be accessible to the operator&#39;s hand at all times. 
     SUMMARY 
     The present disclosure relates generally to a positioning apparatus for theatrical lighting equipment. In particular, the present disclosure is for an apparatus that allows an operator to control the direction of the light beam from a lighting fixture and simultaneously control an iris attached to the lighting fixture. This allows an operator to control the direction of the light beam and the size of the diameter of the light beam with one hand, while allowing a free hand to operate other controls, such as a douser to control the intensity of the light beam. 
     The present disclosure combines the control of the position of a theatrical lighting fixture with the control of the iris, in a motion which is natural and comfortable to the operator, so that by merely pivoting the wrist and hand controlling the position of the light, the operator can adjust the iris size. Single-handed operation of the positioning apparatus of the present disclosure allows the operator to control other aspects of the light, such as color or intensity with their other hand. 
     In accordance with one aspect of the present disclosure, a linkage is made between the iris of the light and a rotatable shaft which acts as the handle of the spotlight. The handle may be configured so that rotating the handle increases and decreases the iris aperture, thereby increasing and decreasing the diameter of the light beam at the discretion of the operator. 
     According to another aspect of the present disclosure, a scale may be provided proximate to the iris handle as a reference to the operator for precise iris positioning. The scale may be illuminated or may be constructed of translucent material, and illuminated by a supplemental light source. 
     According to yet another aspect of the present disclosure, a light baffle may be provided to prevent light leakage from the iris slot on the theatrical lighting fixture. 
     As used herein, it should be understood that the term “spotlight” is meant to include fixed-mount type theatrical lighting fixtures used as a follow-spot device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will be described hereafter with reference to the attached drawings which are given as a non-limiting example only, in which: 
         FIG. 1  is a perspective view showing an embodiment of the iris positioning apparatus of the present disclosure; 
         FIG. 2  is a side elevation view showing the iris positioning apparatus of  FIG. 1  attached to a lighting fixture; 
         FIG. 3  is a top view of the apparatus of  FIG. 1 ; 
         FIG. 4  is a detailed perspective view showing the attachment of the positioner to the iris handle; 
         FIG. 5  is a perspective view showing another embodiment of the iris positioning device of the present disclosure; 
         FIG. 6  is a detailed view of the control assembly of the iris positioning device of  FIG. 5 ; and 
         FIG. 7  is a detailed view of the attachment of the positioner of  FIG. 5  to the iris handle. 
     
    
    
     DETAILED DESCRIPTION 
     While the present disclosure will be described fully hereinafter with reference to the accompanying drawings in which particular embodiments are shown, it is understood at the outset that persons skilled in the art may modify the disclosure herein described while still achieving the desired result of this disclosure. Accordingly, the description which follows is to be understood as a broad informative disclosure directed to persons skilled in the appropriate arts and not as limitations of the present disclosure. 
     Referring to  FIGS. 1 through 3 , the iris positioning apparatus  10  of the present disclosure is configured to attach to a theatrical lighting fixture  1 . The iris positioning apparatus  10  includes a positioner  12  coupled to a positioner control handle  14 . Positioner control handle  14  is attached to the yoke  2  of lighting fixture  1 . 
     A pair of side supports  16 ,  18  are positioned on either side of lighting fixture  1  and coupled to yoke  2 . A transverse support  20  is coupled to and positioned between side supports  16  and  18 . Transverse support  20  is spaced from the yoke  2  to stabilize side supports  16  and  18 . 
     Positioner control handle  14  is attached to yoke  2 , and includes a pair of drums  22 ,  24 , the drums are spaced apart from each other and positioned on opposite sides of positioner control handle  14 . Positioner control handle  14  is mounted in a bearing  26  coupled to yoke  2 . Positioner  12  is wound about each drum  22 ,  24  such that as positioner control handle  14  is rotated in a first direction, positioner  12  unwinds from drum  22  while simultaneously winds onto drum  24 . Likewise, as positioner control handle  14  is rotated in a second direction, positioner  12  winds onto drum  22 , while simultaneously unwinding from drum  24 . 
     It is desirable that the rotation of the handle  14  not greatly exceed the rotation of the human wrist. However, the length of the arc of the iris handle  3  is close to 6 inches, while a comfortable handle diameter is approximately ¾ inch to 1 inch. Therefore, the pair of drums  22 ,  24  are used to increase the arc length generated by the operator while turning the positioner control handle  14 . In the present embodiment, each drum  22 ,  24  is sized with a diameter of 2 inches allowing operability over the total length of the arc of the iris handle. 
     Conversion of the rotational movement of positioner control handle  14  to position iris handle  3  may also be accomplished by other mechanical methods, such as with bevel gears and a shaft extending to the rotational plane of the iris, or by other methods known to those skilled in the art. 
     In the exemplary embodiment, positioner  12  comprises a length of cord such as polypropylene, polyester, nylon or combinations thereof. Positioner  12  may also comprise wire rope, cable, rubber belts, and other embodiments known to those skilled in the art. 
     Because the rotational axis of the positioner control handle  14  is oriented perpendicular to the rotational axis or the iris handle  3 , the rotation applied to the handle must be oriented to the iris. Positioner guides  28 ,  30  are provided at the distal end of each side support  16 ,  18  near the iris handle  3  of lighting fixture  1 . In the present embodiment, positioner guides  28 ,  30  each comprise an eyebolt. Positioner  12  is arranged to pass through positioner guide  28 ,  30  which redirect positioner  12  from drums  22 ,  24  into alignment with iris handle  3 . 
     Positioner  12  is configured to be wound about drum  22 , through positioner guide  28 , attached to iris handle  3 , through positioner guide  30 , and wound about drum  24 . As shown in  FIG. 4 , coupling  32  attaches positioner  12  to iris handle  3 . Coupling  32  may simply be a knot tying positioner  12  to iris handle  3 . Alternatively, coupling  32  may comprise clamps or fasteners known in the art. 
     A tensioner  32  may be provided to maintain tension on positioner  12 , preventing positioner  12  from becoming slack. In the present embodiment, tensioner  32  comprises a spring  40  and pulley  42 . At one end, spring  40  is coupled to side support  16 , the other end includes pulley  42  that engages positioner  12 . A tensioner may also be provided on side support  18  as well, balancing the tension in positioner  12 . 
     Referring to  FIG. 2 , the present disclosure may also include a scale  36  proximate to iris handle  3  allowing an operator to determine the position of the iris handle and to make fine adjustments. A scale illuminator  38  may also be provided. In many instances, the operator of the lighting fixture is in a dark environment, therefore it is advantageous to have an illuminated scale. In the exemplary embodiment, the scale  36  is positioned on the inside surface of transverse support  20  facing the operator so that the iris handle  3  is between the operator and the scale  36 . Scale  36  may be annotated with various iris settings. Scale  36  may also be made of a light conducting material, such as polycarbonate thermoplastic, one example is sold under the trade name LEXAN® by the General Electric Company, allowing the annotations on scale  36  to be readily visible in the dark with additional illumination of scale illuminator  38 . 
     The present disclosure may also include a light baffle  34 , as shown in  FIGS. 1 and 4 . Light baffle  34  is positioned over the top of the iris handle  3  and iris slot  4 . Light baffle  34  reduces errant light leaks from iris slot  4  while still permitting full movement and operation of the iris handle  3 . 
     The iris positioning apparatus  10  of the present disclosure is mounted to a theatrical lighting fixture  1  allowing an operator to simultaneously adjust the orientation of the light beam and the size of the light beam. By grasping positioner control handle  14 , the operator may pivot lighting fixture  1  up and down or from side to side on yoke  2 . At the same time the operator may rotate handle  14 . By rotating positioner control handle  14  in a first direction, the operator unwinds positioner  12  from drum  22  while simultaneously winding positioner  12  onto drum  24 , which causes iris handle  3  to move, adjusting the iris and therefore the size of the light beam. By rotating positioner control handle  14  in a second direction, the operator winds positioner  12  onto drum  22  while simultaneously unwinding positioner  12  from drum  24 , which causes iris handle  3  to move in an opposite direction, adjusting the iris and therefore the size of the light beam. Because drums  22  and  24  are both mounted on positioner control handle  14 , the operator may rotate both drums, and thus control the size of the light beam with one hand while controlling the direction of the light with the same hand. This allows the operator to use the other hand for other controls. 
     In another embodiment of the present disclosure, as shown in  FIGS. 5-7  is adapted for use with traditional theatrical spotlights. A spotlight  100  including a spotlight handle  102  and an iris handle  104  is shown in  FIG. 5 . Located at a forward end of spotlight  100  is a lens  106  and a color changer  108 . The color changer  108  having a number of color filters for changing the color of the light beam of the spotlight  100 . 
     In this exemplary embodiment of the present disclosure, iris positioning apparatus  110  includes a positioner  112  coupled to a handle  114  at the forward end of spotlight  100 . Positioner  112  is also coupled to the iris handle  104 . In this exemplary embodiment, positioner  112  may be a rigid or semi-rigid member. As shown in  FIGS. 5-7 , positioner  112  may include a push rod disposed within a guide tube  116 . Guide tube  116  is attached to the spotlight  100  at attachment points  118 ,  120  by, for example, a removable bracket or clamp. Positioner  112  may be attached to a shaft  122  of iris handle  104 . 
     Positioner  112  may also include an adjustment assembly  124  to vary the amount of travel of positioner  112  for a given angle of rotation of handle  114 . Adjustment assembly includes an arm  126  having a number of apertures  128  positioned along the length of arm  126  configured to receive positioner  112 . Positioner  112  may be disposed within one of the apertures  128 . The travel of positioner  112  may be adjusted by changing the aperture  128 . In the exemplary embodiment, the adjustment assembly  124  includes an arm  126  having apertures  128   a ,  128   b ,  128   c , and  128   d . For a given angular rotation of handle  114 , positioner  112  will have a greater travel when configured at aperture  128   d  than  128   a.    
     Positioner  112  allows an operator to control the positioning of a light beam from a spotlight  100  as well as another attribute of the beam, such as the intensity or the iris size (and thus the diameter of the beam) with a single hand. This is advantageous as typical large followspots are six feet or more in length and the distance between the color-changer  108  and the iris handle  104  may be over three feet. In addition, due to the mass and hence inertia of the unit, the spotlight can be more easily moved with a hand grasping the light closer to the color changer  108 . The iris handle is more commonly near the center of the unit. Multiple devices of this sort can be attached to the theatrical spotlight to control various attributes of the light, or a clutch and system of levers could be arranged to control several attributes of the light with a single handle. 
     This technology may also be applied to a fresnel type light, where the rotation of the handle could be used to control the spot/flood characteristics of the light, or it could be applied to an existing lighting fixture enabling the operator to control aspects of the light such as iris or douser with the same hand which is controlling the position of the light. 
     Additionally, it should be clear to one skilled in the art that the subject matter of the present disclosure may be incorporated into the construction theatrical lighting fixtures, or may be incorporated into a kit for attachment to existing lighting fixtures.