BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing a preferred embodiment of a damper assembly according to the present invention prior to being installed into an air duct of an existing air handling system.
FIG. 2 is a perspective view showing the damper assembly of FIG. 1 installed within the air duct with the damper plate in a fully opened position.
FIG. 3 is a perspective view showing the damper assembly of FIG. 1 installed within the air duct with the damper plate in a fully closed position.
FIG. 4 is a perspective view illustrating a means for adjusting the position of the damper plate within the air duct.
FIG. 5 is an exploded view showing a preferred embodiment of a damper assembly according to the present invention in greater detail.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in greater detail to presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. An exemplary and preferred embodiment of a damper assembly 20 according to the invention is shown in FIG. 1 with the damper assembly outside an air duct 10 of an existing air handling system prior to installing the damper assembly into the air duct. As used herein, “existing air handling system” refers to an air handling system such as a commonly used heating, ventilating and air conditioning (HVAC) system, that is already (i.e., previously) installed and in which air flow adjustments are needed, but for which there is no means of readily installing a conventional damper assembly for regulating air flow through an air duct. Accordingly, the present invention provides a method for readily retrofitting an existing air handling system having at least one air duct to include a damper assembly positioned within the air duct and operable for regulating air flow through the air duct.
Referring now specifically to FIGS. 1-3, the air duct 10 extends outwardly from a central air plenum (not shown) of the previously installed air handling system into a large open area, or into a room of a home or building. The air duct 10 terminates in an outlet end typically comprising a boot 12 and a boot collar 14 for joining the boot to the outlet end of the air duct. As shown herein, the air duct 10 transitions from a generally circular cross-section at the outlet end of the air duct to a generally rectangular cross-section at the outlet end of the boot 12. The outlet end of the boot 12 typically extends through an opening formed in a floor or wall 15 of the room such that air flow through the air duct 10 is delivered to the room. The outlet end of the boot 12 is rectangular shaped in order to receive a conventional grate have movable shutters, as will be described in greater detail below. However, the outlet end of the air duct 10 and/or boot 12 may have any desired cross-sectional shape, for example circular, square, rectangular, elliptical, etc. The present invention is not limited by the specific size, shape and location of the outlet end of the air duct 10. The only requirement is that the outlet end of the air duct 10 is accessible from the interior of the room and that the damper assembly 20 is suitably sized and shaped to be inserted into the outlet end of the air duct from the room and conforms to the interior geometry of the air duct.
Referring now specifically to FIG. 1, the damper assembly 20 comprises a damper plate 22 and a mounting plate 24. The damper plate 22 is movably attached to the mounting plate 24. As shown and described herein, the damper plate 22 is relatively thin and generally circular in shape, while the mounting plate 24 is relatively thin, elongate and generally rectangular in shape. The damper plate 22 and the mounting plate 24 may be made of any suitable material, such as plastic, composite or metal. Preferably, however, the damper plate 22 and the mounting plate 24 are made of the same lightweight and formable metal, such as aluminum. In particular, the mounting plate 24 should be substantially rigid, but at the same time capable of being formed to match the contour of the boot 12, as will be described. The damper plate 22, on the other hand, must be rigid enough to withstand forces generated by air flow through the air duct 10 without buckling or deforming appreciably. In practice, the geometric properties of the damper plate 22 and the mounting plate 24 contribute to their desired degree of stiffness. The damper plate 22 may be movably attached to the mounting plate 24 at any location such that the damper plate engages the outlet end of air duct 10 to regulate air flow through the air dust, as will be described in greater detail below. As shown, the damper plate 22 is movably attached to the mounting plate 24 at one end. However, the damper plate 22 may be movably attached to the mounting plate 24 at a medial location between the opposite ends of the mounting plate. The mounting plate 24 may also be provided with one or more through holes 26 adjacent the end opposite the damper plate 22, for a purpose to be described.
FIG. 2 is a perspective view showing the damper assembly 20 installed within the air duct 10 with the damper plate 22 in a fully opened position. The damper assembly 20 is inserted into the outlet end of the boot 12 from the interior of the room and positioned with the damper plate 22 adjacent the outlet end of the air duct 10. Typically, the damper assembly 20 is inserted into the boot 12 until the end of the mounting plate 24 having the movably attached damper plate 22 is positioned adjacent a lip 13 of the boot collar 14 that meets the outlet end of the air duct 10. As shown, the end of the mounting plate 24 is provided with a hook 25 or other suitable means for engaging the lip 13 of the boot collar 14. The hook 25 is particularly useful to secure the end of the mounting plate 24 adjacent the damper plate 22 to the air duct 10 without special tools or equipment at a location within the air duct that is not accessible for a conventional fastener, such as a sheet metal screw. The mounting plate 24 is configured with sufficient length such that the end of the mounting plate opposite the damper plate 22 will typically extend outwardly from the outlet end of the boot 12. The mounting plate 24 may be provided with a series of spaced through holes 26 so that an appropriate one (or more) of the through holes may be utilized to secure the mounting plate to the interior of the boot 12 adjacent the outlet end with a common fastener 27, such as a sheet metal screw. Alternatively, the mounting plate 24 may be secured to the boot 12 by any other suitable means, such as adhesive, or by one or more rivets in the event sufficient access to the exterior of the boot 12 is available. Any excess length of the mounting plate 24, indicated by broken lines in FIG. 2, is removed (e.g. cut off) and discarded. The structural arrangement of the damper assembly 20 and the method of installing the damper assembly into the air duct 10 of an existing air handling system described herein represent the best mode of practicing the invention presently known to the inventor. However, many other structural arrangements and installations are possible and would be known or readily ascertained by one of ordinary skill in the art. Accordingly, any such structural arrangements and/or installation methods are considered to fall within the intended scope of the present invention.
FIG. 3 is a perspective view showing the damper assembly 20 installed within the air duct 10 with the damper plate 22 in a fully closed position. As previously mentioned, the damper plate 22 is movably attached to the mounting plate 24. Any suitable means 30 for movably mounting the damper plate 22 to the mounting plate 24 may be employed. The means 30 for movably mounting the damper plate 22 provides sufficient resistance to maintain the damper plate in a desired position within the air duct 10 against forces generated by air flow through the air duct, while at the same time permitting the position of the damper plate 22 to be adjusted without requiring the damper assembly 20 to be disassembled. In particular, the means 30 permits the damper plate 22 to be repositioned from the room without loosening or detaching the damper plate from the mounting plate 24. For example, a person may adjust the damper plate 22 from the substantially opened position shown in FIG. 2 to the substantially closed position shown in FIG. 3 to restrict air flow into the room by reaching into the boot 12 and manipulating the damper plate 22 by hand. Preferably, the damper plate 22 is provided with a bracket 28 or other suitable structure that serves as a means for grasping and manipulating the damper plate. As shown, a generally L-shaped bracket 28 is fixed to the damper plate 22 by a fastener, rivet or adhesive, and has an opening 29 through the flange portion extending outwardly from the damper plate in the direction of the boot 12. However, any alternative means, for example a handle, rod or chain, suitable for adjusting the position of the damper plate 22 within the air duct may be utilized.
FIG. 4 is a perspective view illustrating a preferred means for adjusting the position of the damper plate 22 within the air duct 10 utilizing the bracket 28. The means illustrated in FIG. 4 is particularly useful when the outlet end of the boot 12 is covered by a grate 16 having at least one, and preferably, a plurality of movable shutters 17 for restricting air flow into the room. The grate 16 and shutters 17 are commonly referred to as an “air diffuser,” indicated by phantom lines in FIG. 4. Without a damper assembly 20 according to the present invention installed within the air duct 10, a conventional air diffuser tends to make an annoying whistling noise when the shutters 17 are moved to a closed position due to the air flow being forced through the air duct. With the damper assembly 20 installed, the force of the air flow can be substantially reduced by the damper plate 22 before reaching the air diffuser. Since the air diffuser is typically secured to the boot 12 by a plurality of fasteners, such as sheet metal screws, it is desirable to be able to adjust the position of the damper plate 22 without removing the air diffuser to provide sufficient access to manually manipulate the damper plate. Accordingly, an elongate rod 18 may be provided with a generally L-shaped end for engaging the opening 29 through the flange portion of the bracket 28. The shutters 17 of the air diffuser are opened and the rod 18, indicated by broken lines in FIG. 4, is inserted into the boot 12 between adjacent shutters and hooked onto the bracket 28 by threading the end of the rod through the opening 29. The rod 18 is then manipulated to position the damper plate 22 within the air duct 10 to regulate the air flow through the air duct. The rod 18 may be removed once the damper plate 22 is positioned, or may remain engaged with the bracket 28 until the shutters 17 need to be closed.
FIG. 5 is an exploded view showing a preferred embodiment of a damper assembly according to the present invention in greater detail. The damper plate 22 (including bracket 28) and the mounting plate 24 are as previously described, and accordingly, will not be described further with reference to FIG. 5. However, an exemplary means 30 for movably mounting the damper plate 22 to the mounting plate 24 is shown and will be described in greater detail. The particular means 30 shown in FIG. 5 comprises a first mounting bracket 32 and a second mounting bracket 34. The first mounting bracket 32 is attached to the damper plate 22 and the second mounting bracket 34 is attached to the mounting plate 34 in a suitable manner, such as a fastener, rivet or adhesive. As shown, the first mounting bracket 32 is secured to the damper plate 22 by a pair of fasteners, while the second mounting bracket 34 is secured to the mounting plate 34 by a pair of rivets. Regardless, each mounting bracket 32, 34 has a pair of outwardly extending flanges having openings 35 for receiving fasteners to movably attach the damper plate 22 to the mounting plate 34. Each fastener preferably comprises an externally threaded bolt 36, an internally threaded nut 37 and a non-flat washer 38 between the bolt and nut commercially known as a “wave washer.” Such wave washers are known and available from most commercial hardware suppliers. The wave washer 38 provides a sufficient resistance force to maintain the damper plate 22 in a desired position within the air duct 10 against forces generated by air flow through the air duct, while permitting the position of the damper plate 22 to be adjusted as previously described. Without utilizing the wave washer 38, the damper plate 22 would necessarily be attached to the mounting plate 24 either too loosely to maintain the position of the damper plate within the air duct 10, or to securely to permit the position of the damper plate to be adjusted without disassembling the damper assembly 20. Utilizing the wave washer 38 provides a desirable degree of frictional resistance that is somewhat variable by adjusting the tightness of the nut 37 on the bolt 36.
The embodiments described above provide numerous advantages over any known damper assembly for regulating air flow through an air duct of an air handling system. In particular, a damper assembly according to the present invention may be readily installed in an air duct of an existing air handling system when no means of installing a conventional balancing damper is available. Furthermore, the position of the damper plate of the damper assembly can be easily adjusted to regulate air flow through the air duct from a room without the use of tools. In an exemplary and preferred embodiment, the damper plate is movably mounted to a mounting plate utilizing a wave washer that provides a desired degree of resistance. As a result, the position of the damper plate can be easily adjusted through an air diffuser utilizing an elongate rod without detaching the air diffuser from the boot of the air duct.
Particular examples and preferred embodiments have been shown and described herein for the purpose of explaining certain features and advantages of the present invention. However, it will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the claims appended hereto cover any and all modifications and variations of the invention that may be made by one of ordinary skill in the art, provided they come within the scope of the claims and their equivalents.
Patent Application
20080014859
