Lighthead assembly
BACKGROUND OF THE INVENTION 
     1. Field 
     This invention relates to lightheads containing multiple individual spotlights. It is specifically directed to means for adjusting the direction of light beams emanating from such individual spotlights, and provides an improved mechanism for synchronizing the movement of the individual spotlights from one or more remote locations. 
     2. State of the Art 
     Lighthead assemblies with multiple individual spotlights have long been used to provide a substantially shadowless illumination of a work area. A classic application of such assemblies is for the illumination of surgical operating sites. Lighthead assemblies with multiple spotlights evolved as an improvement over earlier operating room lighting fixtures which included expedients to scatter or diffuse the light from a single source. U.S. Pat. No. 1,909,947 illustrates an early arrangement of two spotlights with synchronized adjustment means. According to that arrangement, rotation of a central handle moves linkage structure which tilts the individual spotlights to change the direction of the light beams emanating therefrom. The light beams are thus caused to intersect (converge) at a selected distance from the spotlights. In this fashion, the shadow cast upon the illuminated area is reduced as compared to the shadow inherent with single source illumination. U.S. Pat. No. 3,055,087 discloses a more refined multi-beam lighthead assembly which provides synchronous orientation of a plurality of light beams by means of a cylindrical ring coupled by cam slots to individual spotlights arranged around the perimeter of the ring. U.S. Pat. No. 3,887,801 discloses another multi-beam lighthead assembly with a synchronized focusing mechanism. In this arrangement, a central cam ring is rotated by a handle axially disposed with respect to the assembly. The disclosures of U.S. Pat. Nos. 3,005,087 and 3,887,801 are incorporated by reference as portions of this disclosure for their detailed discussions of surgical lights with adjustable multi-beam lighthead assemblies, the objectives of such assemblies, and the mechanical linkages heretofore relied upon to effect synchronous linear shifting of the light beams emanating from multiple spotlights within the lighthead. 
     The various lighthead assemblies in current use have certain limitations and disadvantages. In a surgical setting, it is important for scrubbed personnel who are actually involved in a surgical procedure to be able to adjust (focus) the illumination resulting from the intersecting individual light beams. For this purpose, a centrally disposed handle, usually oriented parallel the central axis of the lighthead, is optimal. Such a handle must be capable of sterilization, and cannot be permitted to become contaminated during a procedure without imposing the concurrent constraint on scrubbed personnel of avoiding further handle contact. In many instances, however, it is either necessary or convenient for non-scrubbed personnel to focus the illumination while the surgical procedure is in progress. Such personnel cannot be permitted to contact a focusing handle which is required to remain uncontaminated. Currently available lighthead assemblies are not sufficiently adaptable to accommodate to these conflicting demands. 
     The synchronized focusing arrangements suggested to date have been structured with individual spotlights arranged in a circle, dedicating the region circumscribed by the lights to mechanical components. This arrangement limits the illumination obtainable at the center of an illuminated site and also limits the gradation of illumination obtainable from the center to the peripheral areas of the illuminated site. 
     SUMMARY OF THE INVENTION 
     The multiple beam lighthead assembly of this invention includes a lighthead and associated handle structure external said lighthead. The handle structure is linked to individual spotlights housed within the lighthead, and constitutes means for focusing illumination produced by the lighthead. 
     The lighthead includes a plurality of structurally similar pods, each of which includes a lamp, and may also include associated lenses, filters, reflectors and/or associated mechanical and/or electronic components. In any event, each pod may be regarded as including a spotlight which produces a light beam when the lighthead is energized. 
     Significantly, the lighthead includes a central pod constructed and arranged to produce an approximately axial light beam with respect to the lighthead. Ordinarily, the lighthead will deliver light through an approximately planar platform surface of a faceplate disposed between the pods and at least a portion of the handle structure. For purposes of this disclosure, a light beam emanating from the central pod in a direction approximately normal that planar surface is regarded as &#34;axial.&#34; 
     A multiplicity of peripheral pods are mounted symmetrically around the central pod on pivot mounts. The peripheral pods are constructed and arranged to produce light beams, when the lighthead is energized, in a symmetrical pattern with respect to the axial beam of the center pod. In most instances, the peripheral pods are arranged to produce light beams forming a circle whose center is intersected by the axial light beam. The pivot mounts permit displacement of the pods (or at least the portion of the pods including the lamps) within a range of movement. By displacing the peripheral pods a selected amount, the light beams emanating therefrom are caused to intersect (converge with) the axial light beam at a corresponding resultant location (the illuminated area). Movement of the intersection point (region of convergence) along the axial light beam is regarded as &#34;focusing&#34; within the context of this disclosure. 
     Coordination means disposed within the lighthead provide synchronized movement of the peripheral pods. Each pod is thus displaced an equivalent amount to assure that all peripheral light beams simultaneously intersect at the same location along the axial light beam throughout the entire range of movement permitted by the respective pivot mounts. The coordinating means may take various forms. As currently preferred, it includes a rotatable cylindrical surface element and reaction means operably associated with each peripheral pod and the cylindrical surface element. The surface element constitutes or otherwise carries a camming surface means (slots, grooves, ramps, bosses, etc.) and is mounted to rotate on an axis approximately parallel (typically congruent) with said axial light beam. The reaction means pivots (displaces) the pods in a first direction in response to clockwise rotation of the cylindrical surface element and in a second direction opposite the first direction in response to counterclockwise rotation of that element. Although the cylindrical surface element may comprise a surface of an upstanding cylindrical tube disposed to circumscribe the central pod, the term &#34;cylindrical,&#34; is intended in this disclosure to include any mechanically equivalent configuration which permits the presence of a central pod while providing for synchronous movement of the peripheral pods. 
     Also housed within the lighthead are all, or a major portion, of the mechanical components required to rotate the cylindrical surface element. These components constitute drive means and are mechanically coupled to the cylindrical surface element as well as to external handle structure. A significant feature of the preferred embodiments of this invention is the provision of separate handle structures for use by scrubbed personnel from a first location and unscrubbed personnel from a second location remote from the first location. The first, or sterile, handle is typically located near, often congruent with, the axial light beam. In practice, any shadow induced by this location of the handle is reilluminated by redistributed light from the central pod. The contribution of the central light beam is thus not materially impacted by the handle or associated mounting structure. The second, or non-sterile, handle is typically located at the perimeter of the lighthead for ready, non-interfering access. Ideally, at least the first handle is removable and either sterilizable or disposable. 
     Each pod normally includes a cover lens. The first, axial, handle may connect to a drive post which protrudes through the cover lens of the central pod. This post may releasably couple through a detachable drive assembly to the coordination means, thereby permitting access to the central pod for cleaning or lamp replacement. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings which illustrate what is currently regarded as the best mode for carrying out the invention: 
     FIG. 1 is a partial perspective view from the top of a lighthead embodying the invention with a portion of the housing removed to display internal components; 
     FIG. 2 is an exploded view of a preferred embodiment of the invention; 
     FIG. 3 is a perspective view illustrating a portion of the mechanism shown in FIG. 2 in assembled condition; 
     FIG. 4 is a fragmentary cross-sectional view illustrating a typical coordination mechanism of this invention and associated drive components; 
     FIG. 5 is an enlarged exploded view of a removable drive mechanism illustrated in FIG. 2; and 
     FIG. 6 is an enlarged fragmentary perspective view of a portion of the structure illustrated by FIG. 3. 
    
    
     DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
     The drawings illustrate a lighthead assembly, designated generally 11, with a central pod, designated generally 12 and five symmetrically arranged, substantially identical peripheral pods, each designated generally 13. 
     Each of the pods 12, 13 includes a spotlight assembly 20. The assemblies 20 of the peripheral pods 13 each include a circumferential support ring 22, which may be integral with, but is illustrated as a separate mounting element for, the reflector 25. The support rings 22 are supported at diametrically opposed circumferential locations by pivot mountings 27, 29. The pivot mountings 27, 29 are located to permit tilting of the mounting rings 22, and thus the reflectors 25, on an axis A which is transverse and non-intersecting with the central axis C of the central pod 12. As illustrated, the pivot mountings 27, 29 of all of the peripheral pods 13 define a circle which is concentric with respect to the stationary reflector 31 of the central pod 12. A typical arrangement of the type illustrated permits aiming the light beam emanating from a peripheral pod 13 so that it intersects the axial light beam emanating from the central pod 12 at selected locations ranging from about 21/2 to about 6 feet distant from the faceplate 33 of the lighthead 11. The pivot mountings 27, 29 are supported from the platform 34 on studs 35 which may be adjustable, e.g. by threads (not shown), to constitute adjustment means. 
     A separate mechanical linkage, designated generally 40, couples each support ring 22 with a cam ring 41. The cam ring 41 may take the form of a cylindrical annulus, as shown, defined by inner and outer cylindrical walls 42, 43. As illustrated, a threaded stud 45 extends down from the support ring 22, terminating in a ball joint connection 46 with a pin 47 carried by a cam ring follower ring 48. The ring 48 is dimensioned to reciprocate within the cam ring 41. The ball joint connector 46 illustrated constitutes a presently preferred self-aligning bearing. Individual pins 47 are cantilevered from the ring 48 through corresponding inclined cam slots 49 provided through the wall of the cam ring 41. As the ring 41 is rotated clockwise or counterclockwise, the pins 47 are urged either up or down, respectively, thereby tilting in linear synchronized coordination the peripheral pods 13 on their respective pivot mounts 27, 29. 
     The cam ring 41 is mounted to encircle the center pod 12. It is supported by an idler wheel arrangement including spaced idler wheel assemblies, designated generally 50, including grooved cylindrical support wheels 51 mounted to rotate on axles 52 anchored to the platform 34. The grooved wheels 51 engage the rim of a drive ring 57 which supports the cam ring 41. A portion 59 of the drive ring is provided with gear teeth adapted to mesh with the corresponding teeth of a drive spur gear 60. The spur gear 60 constitutes a portion of a drive mechanism best illustrated by FIG. 4. Although the mechanism illustrated is regarded as practical and reliable, various gear systems, friction drives, belt drives, chain drives and their respective equivalents can be substituted for the assembly shown. The invention contemplates the use of any drive means which can be adapted satisfactorily to mechanically couple with and serve to rotate the cam ring 41 by means of a remote handle mechanism. 
     Referring to FIG. 4, a first, sterilizable handle 65 is detachably connected to a first shaft, (the drive post 66) by means of a spring-actuated coupling mechanism, designated generally 67. The handle 65, post 66 and mechanism 67 illustrated are disclosed in more detail in co-pending U.S. patent application Ser. No. 07/319,048, filed Mar. 6, 1989, now U.S. Pat. No. 4,878,156. The post 66 is mounted to protrude through a cover lens element 68 of the central pod 12 and is coupled to a drive shaft 70 through matched bevel gears 72, 73. The shaft 70 is journaled through bearings 75, 76 in structural ring 77 of a central focus drive module, designated generally 78 (see FIG. 5). Shaft 70 terminates in a male spline 79 which mates with a female spline 80. Shaft segment 81 extends from the lighthead platform 34 and attaches to a second handle (the knob 82). Rotation of the shaft 70 in either direction by either of the handles 65, 82, causes a corresponding rotation of matched bevel gears 83, 84 and thus the spur gear 60, thereby turning the cam ring 41. 
     The shaft 81 extends through a notch 85 in the upstanding wall 86 (see FIG. 6), and is journaled through bearings 87, 88 in supports 90, 91. The central lens 68 and central focus module 78 are attached to bosses 92 extending from the wall 86 by screws 93 (see FIG. 5). The focus module 78 and handle 65 are thus located in an inherently non-illuminated zone, except for the structural supports 94. The shadow induced by the supports 94 is negligible. 
     Relamping and cleaning of the central pod 12 is easily accomplished by removing the cover lens 68 with the central focus module 78 attached. Relamping and cleaning of the peripheral pods 13 requires removal of cover lenses 95 in conventional fashion. 
     Reference herein to details of the illustrated embodiments is not intended to limit the scope of the appended claims which themselves recite those features regarded as important to the invention. It will be apparent to those skilled in the art that the benefits of the disclosed invention can be obtained by the substitution of various mechanical expedients equivalent to those specifically disclosed and illustrated. Moreover, the drawings illustrate a number of components which, while not referred to specifically in the specification, should be instructive to one of ordinary skill in the art.