US3344270A

US3344270A - Linearly pivoting light diffuser hanger

Info

Publication number: US3344270A
Authority: US
Publication date: 1967-09-26
Anticipated expiration: 1984-09-26

Description

p 26, 1967 F. E. RYDER 3,344,270

LINEARLY PIVOTING LIGHT DIFFUSER HANGER Filed Jan. 5, 1966 2 h e h l INVENTOR. Francis E Ryder His Aff'ys F. E. RYDER Sept. 26, 1967 LINEARLY PIVOTING LIGHT DIFFUSER HANGER 2 Sheets-Sheet 11 Filed Jan. 5, 1966 lllllllilnl-Wl INVENTOR. Francis E. Ryder His Arr s United States Patent Ice 3,344,270 LINEARLY PIVOTING LIGHT DIFFUSER HANGER Francis E. Ryder, Bartlett, Elf, assignor to Illinois Tool Works Ina, Chicago, 111., a corporation of Delaware Filed Jan. 3, 1966, Ser. No. 518,347 12 Claims. (Cl. 240144) The present invention relates to a new and improved light diffuser hanger, and more particularly, to a light diffused hanger assembly for adjustably mounting a diffuser panel relative to a fixture element.

Commercial buildings are being designed today to permit rearrangement of internal wall partitions and consequent change of room sizes to meet varying demands. Where such building systems are employed, it is recognized that lighting arrangements must be versatile enough to retain lighting effectiveness as room sizes change without extensive modifications. The ability to rearrange lighting-ceiling components to provide the required light intensity as well as meet various types of lighting requirements-semi-indirect, direct, and luminous ceilinghas thus become an important part of a flexible building system.

In the usual case, light diffuser panels are mounted in close proximity to lighting fixtures to minimize glare and spread the light intensity over a predetermined area. The number, type and location of light diffuser panels to lighting fixture elements determine the type of lighting desired, and this makes the support or mounting of the light diffuser panel a particularly important aspect of a versatile lighting arrangement. Although there are various ways to support light diffuser panels from a ceiling structure, it has been found convenient to mount or support the diffuser panels by hanger structures which are in turn mounted to the lighting fixture elements. Yet this mounting arrangement does not accommodate itself to the builtin versatility of the aforementioned lighting system unless some way is provided to regulate or adjust the relationship of the diffuser panel relative to the fixture elements without requiring the use of hanger structures of different s1ze.

Accordingly, it is an object of the present invention to provide a new and improved light diffuser hanger for adjustably mounting a diffuser panel relative to a fixture element.

More particularly, it is an object of the present invention to provide a light diffuser hanger which permits ver tical adjustment of a diffuser panel relative to a fixture element to meet varying requirements of a versatile lighting arrangement.

Another object of the present invention is to provide a light diffuser hanger structure which affords convenient access thereto for regulating the prescribed relationship of a diffuser panel relative to a fixture element.

Still another object of the present invention is the provision of a light diffuser hanger of the aforementioned type which provides relatively precise adjustment of the hanger components without any substantial slipping therebetween, eliminates the strain of components working against one another, and yet is made from a minimum number of parts.

Still another object of the present invention is the provision of a light diffuser hanger of the foregoing type which can be quickly and easily mounted to a lighting fixture element in a releasable fashion while at the same time providing a reliable and relatively stable supporting arm or arms for a diffuser panel.

These and other and further objects and advantages are obtained by the provision of at least one elongated supporting arm which is pivotally mounted at one end to a fixture element and at its other end supports a diffuser 3,344,276 Patented Sept. 26, 1967 panel, the supporting arm adapted to be moved in a pivotal fashion while the pivot point thereof is shifted predetermined increments to obtain the desired relative adjustment of the diffuser panel to the fixture element.

Reference is now made to the drawings for the illustrative embodiment of the present invention wherein:

FIG. 1 is a fragmentary perspective view of a lighting ceiling arrangement incorporating hanger structures or assemblies as constructed in accordance with the present invention;

FIG. 2 is an exploded perspective view of one light diffuser hanger structure or assembly which is used preferably in the environment shown in FIG. 1;

FIG. 3 is a side elevational view of a bracket member which is used in each light diffuser hanger structure or assembly;

FIG. 4 is a fragmentary bottom plan view of a fixture element with a light diffuser hanger structure mounted thereto;

FIG. 5 is a diagrammatic representation illustrating various positions of a hanger supporting arm, the outer end of which moves in a linear path for reasons which will hereinafter appear;

FIG. 6 is a fragmentary enlarged top plan view of a light diffuser hanger structure in the vicinity of its bracket member and other proximate components; and

FIG. 7 is a side elevational view of a rotary threaded screw member used in each light diffuser hanger structure of the present invention.

In the discussion that follows, the light diffuser hanger structure or assembly will be discussed in terms of a pair of supporting arms which cooperatively engage a diffuser panel and support it relative to a light fixture element. It is to be specifically understood, however, that insofar as the scope of the present invention is concerned, a light diffuser hanger may include only a single supporting arm which is appropriately configured itself, or which includes additional parts, to enable it to support one or more diffuser panels as desired.

Referring now to the drawings, and first to FIG. 1, there will be seen a lighting-ceiling system including a metal grid 10 suspended from the roof structure which supports within the open spaces thereof a sheet metal lighting coffer as shown as a flat ceiling pan. Both the grid and lighting coffer can be made of prefinished sheet steel, provided with perforated surfaces for increased sound absorption, and backed with mineral wool batts to provide fireproofing and sound absorption features as desired. Each of the lighting coffers as fiat ceiling sections support one or more two-lamp strip fixtures which mount a pair of fluorescent bulbs in a conventional fashion as shown. A diffuser panel with translucent properties, preferably made from a rigid plastic material, is positioned beneath each fixture element 30, and supported by two pairs of light diffuser hangers which are in turn supported by the fixture element 30 as illustrated.

As best seen in FIG. 2 of the drawings, each light diffuser hanger 60 includes a supporting arm 62 which can be conveniently subdivided for purposes of discussion into a first end section 64, and intermediate or middle section 66, and a second end section 68. The first end section 64 is pivotally mounted to a corresponding fixture element 30 preferably by way of the other components shown in FIG. 2, and for this purpose, is provided with a pair of laterally extending cars having aligned openings 72 which receive a pivot pin structure 78 in a manner to be described in detail below.

The intermediate or middle section 66 of the supporting arm 62 extends downwardly and away from the first end section 64 at an obtuse angle thereto, and at such a dimension to clear the lamp 40 at any setting.

3 The lower end of the supporting arm 62 is integrally joined to the second end section 68 which first extends laterally away from the intermediate or middle section 66 and terminates in a reversely extending foot 74 with holes 75 to allow light transmission and minimize shadows. Eachfoot 74 underlies one of the inturned flanges 52 of the light diffuser panel 50 as illustrated in FIG. 1. The elongated supporting arm 62 is preferably a stamped and bent sheet metal component with an invested channel-shaped configuration to afford prescribed reinforcing capabilities.

The ears 70 of the supporting arm 62 are pivotally attached to the U-shaped bracket member 76 by way of the sheet metal nut/ pivot pin stamping 78, the latter in turn being connected to the rotary threaded screw member 80 for reasons which will appear hereinafter. As best seen in FIGS. 2-3 and 6, the bracket member 76 includes a bight end portion 82 with a pair of upstanding, generally parallel leg portions 84 extending from opposite sides thereof. A cam slot 86 is provided in each of the leg portions 84, and arranged in mirror image relationship with each other. The cam slots 86 are designed to receive the oppositely directed pivot pins 88 which are integrally attached to the nut/pivot pin stamping 78. The pivot pins 88 are first passed from the inside through the aligned opening 72 provided in the ears 70 of the supporting arm 62 and then through the slots 86 of the leg portions 84 so as to pivotally mount the supporting arm 62 to the bracket member 76. In so doing, it will be apparent that the ears 70 will be initially spread open to permit the pivot pins 88 to be passed through the openings 72.

The sheet metal nut/ pivot pin device 78 also includes at least one helical thread 90 which is complementary to the helical threads of the screw 80. The screw 80 is first threadably connected to the sheet metal nut/pivot pin device 78 by way of the helical thread 90, and then assembled to the bracket member 76 in a manner to be described in detail below. Rotation of the screw thread member 80 will increase or decrease the threaded engagement with the helical thread 90 of the nut member/pivot pin stamping, the effect of which is to move the latter and thereby the supporting arm 62 along the cam slot 86 for adjusting or regulating the elongated supporting arm 62 of a light diffuser hanger 60 in a manner to be described in detail below.

Each bracket member 76 is adapted to be mounted to one of the inclined sidewalls 32 of the fixture element 30 in the manner best seen in FIG. 5 of the drawing and for this purpose includes a pair of spaced arm or

foot members

92, 94 extending outwardly away from the bight end portion 82 of the bracket member 76 as best illustrated in FIG. 3 of the drawing. The foot member 92 is generally L-shaped and is substantially inflexible whereas the foot member 94 is hook-shaped and resilient to afford snap action engagement with one of the walls 32 of a fixture element 30. At the free end of the hook-shaped resilient foot 94, there is provided a wall engaging finger or prong 96 which cooperates with the inflexible foot 92 in releasably mounting the bracket member 76 to one of the walls or panels 32 of the fixture element 30 as will now be described.

Each of the walls or panels 32 have an opening 34 generally complementary to, but slightly larger than the foot member 92, a round hole 38, and a notch 36 extending from the outer marginal end of a wall or panel 32, all of which we aligned with each other as shown in FIG. 4. The distance or dimension x between the innermost marginal portion of the aligned opening 34 and notch 36 is greater than the spacing y between the innermost portions of the foot 92 and the finger or prong 96 of the foot 94. As a result, it is a relatively simple matter to assemble a bracket member 76 to a wall or panel 32 with the

foot members

92, 94 of the bracket member thereafter serving to effectively retain the bracket member in the desired position. More particularly, the assembly of a bracket member 76 to a wall or panel 32 is accomplished first by inserting the inflexible foot member 92 within the opening 34 provided in the wall or panel 32, and then moving the hookshaped resilient foot member 94 into engagement with a marginal portion of the wall or panel 32 adjacent the notch 36 thereof. In so doing, the finger or prong element 96 will first engage the marginal portion, and due to its configuration will cause the spacing between the

foot members

92, 94 to be increased from the dimension y to at least the dimension x for movement of the finger or prong elements 96 past the wall or panel 32 at which point the distance between the

foot members

92, 94 will be reduced again to the spacing or dimension y by the snap-action engaging movement of the finger or prong element 96 with the lower face of the wall or panel 32. The finally mounted position of the

foot members

92, 94 to a wall or panel member 32 is best seen in FIG. 4 of the drawing. Tabs on surface 84 are of a width slightly less than notch 36 and stabilize the assembly laterally.

Prior to mounting the bracket member 76 of a light diffuser hanger 60 to a wall or panel 32 of a fixture element 30, the various components of the hanger 60 will first have been assembled to each other. The assembly of the arm 62 with the nut/pivot pin stamping 78 and the bracket member 76 has already been discussed. The screw member 80 is assembled to the bracket 76 and thereafter restrained from movement with respect thereto except by increasing or decreasing the threaded engagement with the nut/ pivot pin stamping 78. The screw member 80, as best seen in FIGS. 2 and 7 includes an enlarged head 100 of predetermined size, the undersurface 102 of which tapers downwardly and inwardly and merges with the unthreaded shank section 104 which in turn is connected to the threaded shank section 106. A washer element 108, which may either be separate or integral with the screw member 80, i located in the vicinity of the juncture between the threaded and unthreaded sections of the shank and is limited axially to prevent movement past the screw threaded section. The washer 108 preferably has a curvilinear upper surface for reasons which will appear hereinafter.

The screw head 100 is passed through openings or slots provided in the bight end portion 82 of the bracket member 76, and then moved into assembled relationship therewith. As best seen in FIG. 6 of the drawings, the opening in the bight end portion 82 preferably include first and second interconnected slots 110, 112. The first slot 110 is large enough to receive the head 100 of the screw member 80 when inserted from the side as depicted by the phantom and full lines shown in FIG. 6. The slot 112 is, however, of-smaller transverse width than the minimum transverse dimension of the screw head 100, but larger than the diameter of unthreaded shank section 104 so that the screw member 80 is restrained by the head 100 in moving inwardly of the bracket 76. Furthermore, when the unthreaded portion 104 of the screw member 80 is received within the slot 112, the washer 108 will be positioned for engagement with the internal wall surface of the bight end portion 82 to completely restrict axial movement of the screw member 80 when thus positioned in the slot 112.

There will be the possibility that the screw member 80 will move from the slot 112 into the slot 110, but there are several features incorporated in the present invention which will prevent inadvertent disassembly of the screw member relative to the other components of the hanger. First of all, the maximum transverse width of the slot 110 is sufficiently smaller than the minimum diameter of the head 100 such that while it will permit assembly or movement of the enlarged head therethrough when disposed at an angle thereto as shown in FIG. 6, it will not allow the screw head 100 to pass therethrough unless disposed at the angular relationship. This will be prevented because the end of the screw member 80 is threadably associated with the nut/pivot pin stamping 78 which itself is snapped into place by first spreading the ears 70 for receiving the pivot pins 88 within the openings 72 thereof, and this assembly is then associated with bracket 76 by spreading legs 84 to enable the pivot pins to be snapped into the cam slots 86. There would nevertheless be a slight transverse shifting of the screw member relative to its axi in a direction toward the slot 110, and this would make precise adjustments of the hanger components difiicult.

To forestall this transverse displacement of the screw member it is to be noted that the second slot 112 is formed in a laterally outwardly directed protuberance 114 which is designed to be received within an opening 38 provided in the wall or panel 32 of a fixture element 30 as best seen in FIG. 4. The size of the opening 38 is just large enough to receive the protuberance 114 for closing olf the slot 110. This will not only prevent inadvertent displacement of the screw member 80 from the slot 112, but will effectively prevent any transverse shifting thereof and provide adjustment capabilities of a relatively precise nature.

The washer member 108 is provided not only for the purpose of restraining rearward axial movement of the screw member 80 should there be a threaded disengagement with the nut/pivot pin stamping 78, but is designed to abut against the inner Wall surface of the protuberance 114 and cooperate with the undersurface 102 of the screw head 100 to provide a relatively smooth adjustment and minimize strain on the working components of the hanger. Specifically, the outwardly directed protuberance 114 has a curvilinear shape generally complementary to the undersurface 102 of the screw head 100 which contacts the exterior surface thereof, and the top surface of the washer 103 which engages the interior wall surface of the protuberance. This will enable the screw member 80 to move the nut/ pivot pin stamping 78 and thus the elongated arm 62 along the cam slots 86 while at the same time changing its angle of inclination, as indicated by angle 1 in FIG. 5, with respect to the bight end portion 82 of the bracket member without in any way interfering or impeding with the operation of the screw member 30 or any other component of the hanger 69. Thus, relatively little or no strains will be imparted to the various components of the hanger 6i and a smooth, relatively precise adjustment of the supporting arm is possible. When a light diffuser hanger 69 is assembled to a wall or panel 32 of a fixture element 30, the bracket member will assume generally the position seen in FIG. 5 of the drawing, the elongated arm 62 assuming any one of several positions because of its adjustment capability. Each elongated supporting arm 62 is capable of being readily adjusted to the desired position by simply rotating the screw member 80. It will be noted that the head 100 of the screw member 80 is held by the protuberance 114 in a position slightly beneath the lower face of a wall or panel 32 as seen in FIG. 5, thereby affording convenient access thereto.

In the preferred embodiment of the invention as readily depicted in FIG. 1 of the drawing, the light diffuser hangers 60 are preferably used in generally opposed pairs for adjustably mounting the light diffuser panel 50 relative to the fixture element 30 from which the generally opposed pairs of light diffuser hangers extend as shown. The outer or free ends 74 of each elongated supporting arm 62 are designed to engage the inturned flanges 52 of a diffuser panel and thereby support it in a predetermined position relative to its corresponding fixture element 30.

In order to adjust or position a diffuser panel 50 in a desired location relative to a fixture element 30, it is important that the panel engaging end 74 of each supporting arm is maintained in a linear path substantially parallel to a vertical plane passing through the fixture element from which each light diffuser hanger extends throughout predetermined incremental movements of each supporting arm 62. The importance of this prescribed relationship will become apparent when it is recognized that the transverse dimension between the generally opposed inturned flanges 52 on each diffuser panel 50 is fixed. Thus, when the elongated supporting arms 62 of each light diffuser hanger 60 are mounted to a corresponding stationary fixture element 39, some means must be provided to maintain each of the panel engaging ends 74 in a linear path or common plane substantially parallel to a vertical plane passing through the fixture element in order to obtain the desired adjustment.

It has been found advantageous to accomplish this by pivotally mounting one end of each elongated supporting arm 62 to a fixture element by way of the bracket member 76, and then vertically displacing each supporting arm and laterally shifting the pivot point thereof predetermined increments as compensating distances which are sufiicient to maintain the panel engaging end 68 of each supporting arm in the desired linear path throughout various attitudes of each supporting arm.

Upon reflection, it will be apparent that the structure of the light diffuser hanger 60 heretofore discussed will provide the desired movement. More specifically and with particular reference to FIG. 5 of the drawing, the desired movement will be discussed in terms of the specific hanger structure illustrated in the drawing and heretofore described. Although only a single light diffuser hanger 60 is shown in FIG. 5 of the drawing, it will be understood that the operation of a corresponding hanger in a pair of generally opposed hangers as illustrated in FIG. 1 embodiment will be identical.

The supporting arm 62 is shown with a full line position and several dotted or phantom positions in FIG. 5 of the drawings. To regulate or adjust the supporting arm 62 from the full to a dotted line position thereabove, it is necessary to turn the screw threaded member in a counterclockwise direction to increase the threaded engagement of the screw with the nut/ pivot pin stamping 78, and thereby cause the pivot pins 88 of the stamping 78 to move to a lower position along the cam slots 86 as viewed in FIG. 5 of the drawings. As the pivot pins 88 are moved toward the lower end of the cam slots 86 as viewed in FIG. 5 of the drawings, the first end section 64 of the supporting arm 62 engages the wall 32 at a different point. (The first end section 64 of each supporting arm is received within a notch 36 provided in a wall 32 and rests against the innermost marginal portions adjacent the notch 36.) In other words, the fulcrum point of each supporting arm is changed as the pivot pins 88 are moved along the cam slots 86, thereby changing the effective length of the supporting arm projecting past surface 32. When the pivot pins 88 are moved toward the lower end of the cam slots 86, the distance between the pivot pins and the fulcrum point on the panel or fixture identified by letter F will be increased whereas when the pivot pins 88 are moved toward the upper reaches of the cam slots 86, the effective distance between the pivot pins 88 and the fulcrum point F will be shortened. This will result, as viewed in FIG. 5 of the drawings, in a movement of the supporting arm 62 toward the left as it is raised from the full to the dotted line positions thereabove while being moved toward the right as it is lowered from the full to the lowermost dotted line position.

The relative size and configuration of the hanger component, such as the curvature of the cam slots 86, the distance therefrom to the fulcrum point P, etc. willbe determinative of the paths of movement for each panel engaging end 74. To accommodate a diffuser panel 50 of fixed dimensions, the panel engaging end of each supporting arm 62 is designed to move in a linear path or common plane substantially parallel to a vertical plane passing through the fixture element 30 to which a respective supporting arm 62 is attached. This desired movement for each panel engaging end can be readily depicted in FIG. 5 of the drawings. It will thus be understood that although each supporting arm can be moved to various predetermined attitudes, the distance from the fulcrum point F and the outer free extremity of each panel engaging end when measured horizontally will remain in the same to accommodate diffuser panels 50 of the fixed dimension.

It is, of course, to be understood that various modificae tions of the present invention are possible. For example, an alternate form of the present invention might include the elimination of nut/pivot pin stamping 78, and the formation of a threaded helical impression corresponding to the helical thread 90 of the nut/ pivot pin in the bracket member 76 generally in the vicinity of the protuberance 114 for reception of the threaded portion of the screw member. In conjunction with this, the cam slots 86 could take the form of a series of notches connected by a slot so that for adjusting the supporting arm 62, it is merely necessary to move the pivot of the supporting arm into the corresponding notch in the bracket member, and then adjust the screw member for the final adjustment. Another variation of the present invention could take the form of integrally or otherwise uniting the pivot pins 88 with ears 70 of the supporting arm 62, and either providing corresponding holes in the nut/ pivot pin stamping 78 to receive the pivot pins or by entirely eliminating the pivot pin stamping and forming a helical impression in the surface 64 of the bracket member 76 as hereinbefore mentioned. With these examples, it will now be recognized that various modifications within the scope of the claims of the present invention are possible and are contemplated.

It will now be apparent from the foregoing discussion that the present invention contemplates a light diffuser hanger assembly comprising one or more light diffuser hangers, each of which are designed to adjustably mount a light diffuser panel relative to a fixture element although a specific embodiment of a light diffuser hanger has been shown, it will be understood that it is for illustrative purposes only. Various changes in structure will no doubt occur to those skilled in the art, and will be understood as forming a part of the present invention insofar as they fall within the spirit and scope of the appended claims.

I claim:

1. A light diffuser hanger for adjustably mounting a diffuser panel relative to a fixture element comprising, at least one elongated supporting arm pivotally mounted at one end to said fixture element and at its other end engaging and supporting said difiuser panel, said supporting arm being disposed at an angle to a vertical plane passing through said fixture element, and means for both vertically displacing said supporting arm and laterally shifting the pivot point thereof suflicient predetermined distances to position the panel engaging end of said supporting arm at various attitudes in a linear path substantially parallel to said vertical plane and thereby permit vertical adjustment of said diffuser panel relative to said fixture element.

2. The structure as set forth in claim 1 and including a second supporting arm extending from said fixture element in a direction generally opposite said first supporting arm, each of the panel engaging ends of said first and second supporting arms being configured to receive and support inturned flanges of said diffuser panel.

3. The structure as set forth in claim 1 and including a bracket member attached to said fixture element for each of the supporting arms.

4. The structure as set forth in claim 3 wherein each bracket member includes at least one resilient arm for snap action engagement with said fixture element.

5. The structure as set forth in claim 3 wherein said means for displacing and shifting said supporting arm comprises at least one cam slot provided in said bracket member, pivot means associated with said supporting arm and extending through the cam slot, and means for moving said pivot means along said cam slot to obtain adjustment of said supporting arm. a

6. The structure as set forth in claim 3 wherein each bracket member is substantially U-shaped in configuration having a bight end portion and a pair of spaced substantially parallel leg portions, and said means for vertically displacing and laterally shifting said supporting arm includes a cam slot provided on each of the leg portions arranged in mirror image relationship with one another, a nut member having generally opposed pivot pins associated therewith, said pivot pins extending through aligned openings in said supporting arm and through said cam slots, and a threaded screw member threadably engaging said nut member to move its associated pivot pins along said cam slots for adjustment of said supporting arm.

7. The structure as set forth in claim 6 wherein said nut member is a substantially flat element having at least one helical thread and a pair of integral wing elements extending from opposite sides thereof to form said pivot pins.

8. The structure as set forth in claim 6 wherein said threaded screw member is provided with an enlarged head at one end thereof, the undersurface of which is curvilinear in shape for engagement with a complementary shaped protuberance provided on said bracket member to permit unimpeded adjustment of said supporting arm on said bracket member.

9. The structure as set forth in claim 8 wherein the bight end portion includes first and second slot means, said first slot means being large enough to receive the head of the threaded screw member therein, said second slot means being smaller than said screw head to prevent inadvertent removal of said screw member therefrom in one direction after assembly through said first slot means.

10. The structure as set forth in claim 9 wherein said second slot means is formed in an outwardly directed protuberance adapted to be received within an opening of predetermined larger size provided in said fixture element, the marginal portions surrounding the opening in said fixture element preventing said screw member from moving into said first slot means after said bracket member is assembled to said fixture element, the head of said screw member thereby being exposed to facilitate adjustment of said supporting arm.

11. The structure as set forth in claim 9 and including washer means associated with said screw member and engaging the inner wall surface of said bight end portion to prevent retrograde movement of said screw member relative to said bracket member in a direction generally opposite to said first mentioned direction.

12. The structure as set forth in claim 11 wherein each of the components of the hanger are made from sheet metal.

References Cited UNITED STATES PATENTS 522,116 6/1894 Hughes 248291 681,614 8/1901 Bowen et al. 248-291 2,837,307 6/1958 Schwager et al. 248298 3,142,447 7/ 1964 Bodian 248-343 3,263,072 7/1966 Kruger 24078 NORTON ANSHER, Primary Examiner.

M. H. HAYES, Assistant Examiner.

Claims

1. A LIGHT DIFFUSER HANGER FOR ADJUSTABLY MOUNTING A DIFFUSER PANEL RELATIVE TO A FIXTURE ELEMENT COMPRISING, AT LEAST ONE ELONGATED SUPPORTING ARM PIVOTALLY MOUNTED AT ONE END TO SAID FIXTURE ELEMENT AND AT ITS OTHER END ENGAGING AND SUPPORTING SAID DIFFUSER PANEL, SAID SUPPORTING ARM BEING DISPOSED AT AN ANGLE TO A VERTICAL PLANE PASSING THROUGH SAID FIXTURE ELEMENT, AND MEANS FOR BOTH VERTICALLY DISPLACING SAID SUPPORTING ARM AND LATERALLY SHIFTING THE PIVOT POINT THEREOF SUFFICIENT PREDETERMINED DISTANCES TO POSITION THE PANEL ENGAGING END OF SAID SUPPORTING ARM AT VARIOUS ATTITUDES IN A LINEAR PATH SUBSTANTIALLY PARALLEL TO SAID VERTICAL PLANE AND THEREBY PERMIT VERTICAL ADJUSTMENT OF SAID DIFFUSER PANEL RELATIVE TO SAID FIXTURE ELEMENT.