Patent Publication Number: US-6220958-B1

Title: Support bridges for air diffusers including spring loading for air flow control blades

Description:
BACKGROUND OF THE INVENTION 
     The present invention is directed to slot diffusers or air bars that control air flow from a ventilation plenum into a room and, in particular, to improvements in bridges which support air control blades within the diffusers. 
     Air diffusers are used in many different architectural environments for controlling the flow of air form heating and cooling ventilation systems into a room. Because of requirements associated with the geometry of a particular room and because of uneven heating or cooling requirements caused by sunlight or other heating or cooling loads in specific locations, it is often desirable to direct the air flow from the delivery plenum in a particular configuration to best suit the needs of the room. 
     In some instances it is best to have the air flow be a jet-type flow which comes straight out into the room. In other instances the air flow will be more diffuse and/or dampened. And in still other situations it may be desirable to direct air flow to one side or to the other side of the diffuser so that the air travels along a ceiling or wall adjacent to the diffuser. 
     Prior art diffusers have included various air flow controlling surfaces for distribution of the air exiting therefrom. For example, the Hungerford patent U.S. Pat. No. 5,001,967 illustrates a diffuser having air control blades that are adjustable by rotation within the diffuser and act in conjunction with body surfaces of the diffuser in an attempt to control the flow of the air from the diffuser. 
     Where distribution of air flow to the side is desired or where dampened air flow is desired, air flow is usually diverted in some manner within the diffuser so that it does not pass straight through the diffuser. In the present invention, a pair of air control blades work in cooperation with each other and with other surfaces of the diffuser to control air flow. The air flow control blades are positioned to be generally perpendicular to the air flow passing through the diffuser. The blades are supported by bridges within the diffuser and are preferably slidable along the bridges so that the blades can be moved relative to each other in order to control the amount of overlap of one blade over the other which in turn controls the flow of air through the diffuser. The blades are also movable with respect to the bridges and, in particular the blades can also be moved toward one side or the other of the diffuser to operably control the directional output of the air from the diffuser. 
     One problem encountered with movement of blades in this manner is that the blades tend to cock or turn slightly out of alignment with slots receiving the blades such that the blade either incurs sufficient drag to become very hard to move or becomes fully wedged and immobilized. It is also desirable to have a constant slight bias against the blades to hold them in position and to reduce the likelihood that the blades will rattle. 
     Consequently, it is desirable to provide a system for supporting the air control blades in such a manner as to prevent wedging of the blades so as to allow the blades to move smoothly and easily relative to the diffuser and each other, while also holding the blades in place and reducing rattling. In this manner a technician can properly adjust the blades during installation or to modify the position of the blades at a later time. 
     SUMMARY OF THE INVENTION 
     An air diffuser is provided that operates in conjunction with an air delivery plenum to supply heating and ventilation air to a room under directional and volume control of the diffuser. The diffuser includes a pair of slide rails joined by end plates in such a manner as to be operably mountable within a ceiling or a wall surface and to be flow joined with an air delivery plenum. The diffuser also includes at least one pair of bridges which are positioned opposed to each other and a set of air flow control blades which are mounted in and extend between the bridges. The bridges each include a slot for receiving an end of each blade such that the blades may move laterally from side to side within the slot and such that the blades are preferably in overlapping relationship with one another in at least some configurations of the diffuser. 
     The blades are generally parallel to one another and are slidable relative to each other, as well as the bridges so as to be selectively positionable within the diffuser. In this manner the blades may as a pair be positioned anywhere between being fully to one side of the diffuser or fully to the opposite side of the diffuser. Furthermore, the overlap of the blades may be varied to allow more or less spreading therebetween. That is, as the blades slide relative to each other to a more separated position, the space obstructed by the blades increases, thereby producing a greater obstruction to air, and in this way air flow is dampened. For increased flow the blades are positioned for greater overlap. Moving the blades from side to side changes the directional output of the air from the diffuser. Thus, the blade design allows for a wide variety of directional air flows, as well as volumes of air flow through the diffuser. 
     Each of the bridges includes a spring arm that is located within the slot that receives the blades and which engages both of the blades. The spring arm provides a constant bias to the blades that maintains the blades in spaced relationship with respect to a rear wall of each slot, so as to reduce the likelihood that a blade will become wedged against the wall. This allows free movement of the blades within the slot for purposes of adjustment. Furthermore, the spring arm provides a constant small amount of bias to each of the blades so as to prevent the blades from rattling within the diffuser as air passes the blades. 
     The bridges have feet at each end that are slidably mounted in receivers in the side rails to allow movement of the bridges along the side rails, but yet provide support to the bridges. 
     Each bridge also includes an arcuate cover that slopes from rear to front, preferably with a radius equal to the thickness of the bridge, so as to reduce air turbulence. 
     OBJECTS AND ADVANTAGES OF THE INVENTION 
     Therefore, the principle objects of the present invention are: to provide an air diffuser that has air control blades which are adjustable within the diffuser to modify both the directional flow of the air and the volume of the air exiting the diffuser; to provide such a diffuser wherein the blades are supported in an overlapping relationship by opposed bridges within the diffuser and wherein the blades slide relative to each other and to the bridges to allow a technician to position the blades for a desired air volume flow, as well as to adjust directional flow of the air before or after installation; to provide such a diffuser wherein the bridges are self supporting and are easily slidably mounted within side rails of the diffuser to provide support to the blades; to provide such a diffuser wherein the blades are easily removable after installation; to provide such a diffuser wherein the blades are mounted in slots in the bridges and the bridges include a spring arm located in the rear of each slot that continuously biases against the blades during use and prevents the blades from becoming cocked or wedged within the bridges and also which reduces vibration and noise associated with the blades as air passes past the blades; to provide such a diffuser that allows easy adjustment of the blades once the diffuser is fully installed, including removal of the blades, if necessary; to provide such a diffuser which includes comparatively few parts, is easy to assemble and highly stable in use; and to provide such a diffuser which is a relatively easy to manufacture, inexpensive to produce and especially well adapted for the intended usage thereof. 
     Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. 
     The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a ceiling with a diffuser having blade supporting bridges in accordance with the present invention, shown spaced from an air delivery plenum in the ceiling just prior to final assembly, with portions of the ceiling broken away to show detail thereof. 
     FIG. 2 is a fragmentary perspective view from below the air diffuser, showing side rails, the bridges and a pair of blades, with portions broken away to show internal detail thereof. 
     FIG. 3 is a cross-sectional view of the air diffuser, taken along line  3 — 3  of FIG.  1 . 
     FIG. 4 is a cross-sectional view of the air diffuser, taken along line  4 — 4  of FIG. 3, illustrating interaction of the blades with a spring arm and with the blades positioned to be fully spread and blocking flow of air through the diffuser. 
     FIG. 5 is a cross-sectional view of the air diffuser, taken along the same line as FIG. 4, illustrating the interaction of the blades with the spring arm and with the blades fully overlapping so as to maximize air flow through the diffuser. 
     FIG. 6 is an enlarged and fragmentary perspective view of the air diffuser from below with portions broken away to show detail. 
     FIG. 7 is an enlarged and fragmentary cross sectional view of a bridge of the air diffuser, taken along line  7 — 7  of FIG.  3 . 
     FIG. 8 is an enlarged and fragmentary cross sectional view of a bridge of the diffuser, taken along line  8 — 8  of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. 
     The reference in numeral  1  generally designates an air bar or slot air diffuser in accordance with the present invention. The diffuser  1  is shown in FIG. 1 just prior to final installation in a room  4 . The room  4  has a ceiling  5  with an air distribution plenum  6  located above the ceiling  5  opening into a boot  7 . The boot  7  has flanges  9  and  10  that mate with the diffuser  1  and a plurality of snaps or fasteners  11  which secure the diffuser  1  to the plenum  6  and, in particular, to the boot  7 . In this manner air being distributed by the plenum  6  is supplied to the top or plenum facing side  12  of the diffuser  1 . As used herein the terms top and bottom refer tot he diffuser  1  as seen in FIG. 3; however, it is foreseen that the diffuser  1  of the present invention may be used in a variety of orientations, such as in ceilings, walls or the like and the terms refer to direction within the diffuser  1  and not room direction. 
     The diffuser  1  includes a pair of side frame rails  16  and  17  joined at opposite ends by end plates  18 . The diffuser  1  also includes two pairs of bridges  22  and two pairs of air pattern controller blades  23  (FIG.  6 ). In particular, the illustrated diffuser  1  has two sets of blades  23  which may be the same or different depending on the needed air distribution. It is foreseen that diffusers  1  may have only one set of blades  23  or multiple adjacent sets of blades, aligned end to end, as needed. 
     The frame rails  16  and  17  are generally elongate, and each have a sidewall  28  and a bottom flange  29  that extends outwardly from the lower or outer most edge of each side wall  28  in facing relationship to the flange  29  of the opposite side rail, but spaced so as to form a slot  31  therebetween. Each side wall  28  has an interior surface  33  (FIG.  3 ), such that the surfaces  33  of opposed side walls  28  face each other. Likewise each bottom flange  29  has an inward facing or interior surface  34  that is generally perpendicular to the flow of air through the diffuser  1 . 
     The surfaces  33  and  34  cooperate with the blades  23  to control the directional flow of air through the diffuser  1 . Each side wall  28  also includes upper and lower flanges  36  and  37  that cooperate to form a receiver  38  within which a respective side of each of the bridges  22  is received in such a manner as to allow the bridges  22  to be slidably positioned along the rails  16  and  17 . 
     Each of the bridges  22  is sized and shaped to span between a pair of opposed side rails  16  and  17 . Each of the bridges  22  has a pair of feet  41  and  42  (FIG. 2) that extend in opposite directions and are sized and shaped to be slidably received in the receivers  38 . The bridges  22  are thus supported by the side rails  16  and  17 , but are slidable in the receivers  38  during assembly and during certain modifications of the diffuser  1 . 
     Each bridge  22  has a lower wall  44  and an upper wall  45  (FIGS. 7 and 8) that extend between the feet  41  and  42 , are parallel to one another and are spaced by a rear wall  46 . For each bridge  22  the lower wall  44 , upper wall  45  and rear wall  46  form a blade receiving slot  48  (FIG. 8) that operably slidably receives the blades  23 . The rear wall  46  has a central aperture  47  (FIG. 6) located therein. Each of the slot lower walls  44  include a pair of spaced rests  51  that are cylindrical in shape and protrude upwardly from the surface of the lower wall  44  to expose a semi-circular surface  49 . The rests  51  are aligned parallel to the frame rails  16  and  17  and are spaced from each other. The rear wall aperture  47  includes a portion  53  that is located just laterally with respect to the rests  51 . 
     Mounted in each of the slots  48  between the rests  51  is a spring arm or member  56 . Each spring member  56  includes a mounting post  59  that extends between the lower wall  44  and upper wall  45  in close proximity to the rear wall  46  and a spring  60 . Each spring  60  is elongate and curves so as to be arcuate and so as to be bowed outwardly from the rear wall  46 . Each spring  60  is positioned to engage the blades  23  associated therewith, as will be discussed below. 
     Each bridge  22  has a cover  61  that includes a curved or arcuate top surface  62  that is rounded with a radius that is approximately equal to the thickness of the bridge  22  and that allows smooth transition with the slot upper wall  45  from a rear  72  to a front  73  thereof. The rounded feature of the surface  61  reduces drag of air across the bridge  22  and thus reduces noise created by air passing the associated bridge  22 , as this air is less turbulent. Each of the blades  23  includes a generally planar and elongate portion  63  joined along an edge thereof to a rectangular shaped lip or rod  65  that is slightly larger than the planar portion  63  and at an opposite end to a ramp  67  and a second round rod  68  that is comparatively larger in diameter than the thickness of the planar portion  63 . 
     The rod  68  is approximately the same size as the slot  48  so as to be received completely therein in such a manner as to allow the blades  23  to slide within the slots  48 . The rods  68  are slightly longer than the remaining parts of each blade  28 , including the planar portion  63 , ramp  67  and rod  65 . In this manner the rods  63  have pegs or posts  69  that are slot followers and are received further into the slot  48  then the remaining portions of the blade  23  including planar portion  63 . As is seen in FIGS. 3 through 5, the planar portions  63  of the blades  23  have ends  70  that are supported on the rests  51  and abut against a respective spring  60 . 
     In use the bridges  22  receive and support the blades  23  in such a manner as to apply a constant axial bias to maintain the blades  23  in proper position and reduce noise; however, the bias may be simply overcome by a technician to allow removal and replacement of the blades without total disassembly of the diffuser  1  or surrounding room structure. 
     It is to be understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangement of parts described and shown.