Damper for an air duct

Abstract

A damper device for use with an air duct provides a paddle positioned within the duct and an axle extending distally from, and in a common plane with, the paddle through the duct wall, to a position for manual adjustment of the paddle within the duct. A bushing is tightened against the wall of the duct by a threaded knob and frictionally holds the axle in place using a combination of axially oriented fingers and O-rings. A handle is engaged with the end of the axle, enabling manual adjustment of the angular position of the paddle from outside the duct. The handle is in fixed alignment with the orientation of the paddle's peripheral edge, allowing for identification of the approximate angular position of the paddle from outside the duct, even when the duct is covered with a layer of insulation.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not applicable.

REFERENCE TO A “MICROFICHE APPENDIX”

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Present Disclosure

This disclosure relates generally to generally to duct dampers, and more particularly to an air duct damper providing cantilevered construction, ease of installation, and features for improving the ability to locate the damper adjustment control.

2. Description of Related Art including information disclosed under 37 CFR 1.97 and 1.98

Breckenridge, U.S. Pat. No. 160,386 discloses a spindle of a damper plate, constructed with a notch, combined with a spring arranged to enter and bear against the edge of the perforation in the pipe, as well as non-heat-conducting pads arranged in recesses in the handle in each side of the center.

Mears, U.S. Pat. No. 184,255 discloses a rosette-spring, of plate material, constructed as described, in combination with a shaft, disk, and tubular handle, operating to hold a damper in adjusted position in the pipe by frictional contact.

Barler, U.S. Pat. No. 348,947 discloses a damper for stove pipes and hot-air flues comprising the combination of a disk, having an enlargement, journal, angular shank, and screw-seat, a tubular handle, having an enlarged end, and a pipe.

Packham, U.S. Pat. No. 485,053 discloses a damper consisting of a damper-disk having a slideway produced centrally therein, a shank, having at one end a stud forming a journal for one end thereof and recessed, adjacent to the stud, said recess forming an integral overhanging lug or hook adapted to overlie the peripheral edge of the damper-disk received in the recess, the opposite end of the shank having a suitable handle and formed with a shoulder, and a coiled spring on the handle end of the shank, normally tending to press the overhanging lug at the recessed end of the shank into engagement with the peripheral edge of the disk, thereby serving to maintain the engagement of such lug irrespective of any warping of the disk.

Fauth, U.S. Pat. No. 784,997 discloses a damper consisting of a damper-lever having a screw-thread, a damper connected with the lever and fitted in the duct in connection with a locking-nut mounted on the threaded portion of the lever and adapted to be turned thereon against the outer surface of the duct, or a disk or plate thereon, whereby to lock the damper securely in place.

Leo, U.S. Pat. No. 971,285 discloses an improvement in air pipe dampers, the combination with a pipe section having a pair of diametrically opposite openings, and a combined reinforcing block, and bearing in each of said openings, said blocks projecting on the inside of the pipe; of the damper, a pair of oppositely disposed clip members secured to the damper, each of which has a trunnion, one of said trunnions engaging the bearing at one side, the other trunnion being extended through the other bearing or block, said trunnions each having a shoulder for abutting the bearing at their respective sides, the extended trunnion having its outer end apertured, a flat spring plate secured at one end to the pipe and having an elongated slot through which the long trunnion passes, a lever handle comprising a forked cam head eccentrically and pivotally mounted on the outer end of the extended journal, said cam head engaging said spring plate adjacent to its slot, said spring plate being held between said lever and the adjacent part of the pipe section.

Fletcher, U.S. Pat. No. 1,875,581 discloses a combination of a flue and damper oscillatable therein, between open and closed positions with operating mechanism therefor comprising in combination, a housing having a part rotatable therein which is spring pressed in one direction, a trunnion on said damper, a wall plate, an operating member having a hub provided with a circumferential recess and a longitudinal groove, a retaining plate having an opening in which said hub is rotatable and an inwardly extending lip in said recess to hold said operating member and retaining plate against separation except when said groove and lip are in alignment, connections between said member, the rotatable part in said housing and a trunnion on said damper.

Rosenberg, U.S. Pat. No. 1,919,863 discloses a damper plate and damper rod adapted to outstand through the wall of a flue, of a sleeve slidingly and non-rotatingly engaging the rod, a nut threaded onto the rod beyond the sleeve for effecting a relatively clamping action between the sleeve and damper plate, and an annulus surrounding the rod and providing a bearing therefor, directly engaging the rod, the annulus also providing a seat for the end of the sleeve.

Sladky, U.S. Pat. No. 2,412,918 discloses a butterfly valve mechanism comprising a valve body having an opening through which fluid may be conducted, a shaft extending across said opening, a valve disc affixed to said shaft and moveable therewith between closed and open positions, a flat ring of generally washer form surrounding said disc and mounted for swinging movement about the shaft axis, and means for affixing said ring selectively either to the valve body or to the shaft for movement with said disc.

Guildford, U.S. Pat. No. 2,702,504 discloses an air duct control means that provides a damper regulating means which is ordinarily inaccessible to tampering by persons who are not authorized or qualified to make changes in damper adjustments.

Powers, U.S. Pat. No. 2,765,726 discloses a means for re-circulating heating air. The invention provides for using the draft of the incoming hot air to cause a continued re-circulation of the air in the room thereby preventing the stratification so common in which the lower areas are cold and the ceiling areas are hot. This stratification produces the effect of coolness or chilliness to be felt by the occupant of the room.

Kennedy, U.S. Pat. No. 3,070,346 discloses a flow control damper which is simpler and less costly in construction. This invention is adaptable to a wider range of duct sizes without alteration and is adjustable from an operating point within the duct, and is quieter in operation and more effective in sealing the duct fully closed.

Russell, U.S. Pat. No. 4,646,715 discloses an extension apparatus for a damper assembly having an extension member for effectively extending the damper assembly control shaft and a securing member for securing the extension member onto the control shaft.

Inglis, U.S. Pat. No. 4,688,472 discloses a spoiler that is located on the damper blade of a damper assembly such that it serves to divert the flow from the hinge area to avoid air separation. Further, the spoiler does not define the most restricted portion of the flow path and thereby has a minimal effect on the flow resistance.

Shepherd et al., U.S. Pat. No. 4,691,689 discloses an adjustable damper having a tubular duct section defining first and second diametrically opposed openings and first and second sets of detents formed radially from the material of the duct about the respective openings to define a plurality of damper settings.

Myers, U.S. Pat. No. 4,715,581 discloses a damper to be pivotally mounted and eventually clamped in a cylindrical air duct which includes a circular damper blade, a first pivot pin extending integrally radially outwardly from the blade, a damper clip mounted on the opposite side of the blade to have a slideably mounted second pivot pin extending radially outwardly from the blade on the same diameter as the first pin. The blade is provided with a pair of parallel, spaced-apart, and upstanding positioning beads situated to positively position the damper clip and the axis of the second pivot pin. A pair of parallel, spaced-apart elongate, upstanding stiffening beads are spaced from and parallel to the diametrical axes of the positioning pins.

Bernal, U.S. Pat. No. 5,921,277 discloses a damper device for use with an air duct which provides a paddle positioned within the air duct and an axle extending to one side of the paddle, through the duct wall and insulation to a position for manual adjustment of the position of the paddle within the duct. A bushing holds the axle in place, the bushing being tightened against the wall of the duct by a hand nut. The hand nut provides a brightly colored flag that is extendable when the damper device is in place. An O-ring is used to cause a frictional relationship between the paddle axle and the bushing so that the paddle is fixed into place once adjusted. A contour step on the bushing face allows engagement between the paddle and the bushing so as to hold the bushing from rotating while the hand nut is threaded into place on the bushing.

The related art described above discloses dampers. However, the prior art fails to disclose an air damper that is supported from one side of the duct only, is easily installed and operated without tools, and is made entirely of relatively inexpensive molded plastic parts. The present disclosure distinguishes over the prior art providing heretofore unknown advantages as described in the following summary.

BRIEF SUMMARY OF THE INVENTION

This disclosure teaches certain benefits in construction and use which give rise to the objectives described below.

The prior art teaches damper devices providing a disk-shaped control surface or paddle, supported on opposing sides by a threaded stud which penetrates an air duct and is held in place by wing nuts or similar hardware. A handle is mounted on each of the threaded studs in order to facilitate angular positioning of the paddle, the handle also indicating, by virtue of its orientation, the orientation, as well, of the paddle within the duct. It is important to notice that, in order to mount the prior art damper device in this prior art scheme, it is necessary to have physical access to both sides of the duct, something not always available and highly dependent upon details of the construction site. Further, it is clear that the 4 to 6 inches of insulating material that is normally placed around such ducts completely covers the handle so that it normally is difficult for air conditioning service personnel to find the locations of the handles in order to adjust air volume flows within such duct systems. The prior art devices also require a complex construction with springs loading the studs, enabling the studs to be retracted during installation of the paddle. This approach is, of course, expensive in both parts production and required labor.

The applicant's prior patent solved many of these problems by teaching a damper device that is supported from only one side of the air duct, and has a simple installation without using any tools. In addition, the damper device may have flag storage and displaying capabilities for use by workmen.

The present invention significantly improves on applicant's prior patent by teaching a damper device for use with an air duct which provides a paddle positioned within the air duct and an axle extending to one side of the paddle, through the duct wall, to a position for manual adjustment of the paddle within the duct. A bushing is tightened against the wall of the duct by a threaded knob and frictionally holds the axle in place using rubber O-rings so that the paddle is fixed into place once adjusted. A bar handle is engaged with the end of the axle, enabling manual rotation of the axle, and adjustment of the angular position of the paddle, from outside the air duct. The handle is in fixed alignment with the orientation of the paddle's peripheral edge, and the knob provides angle-related marker means. Thus, the handle and the marker means cooperate, as the handle is rotated, to identify the approximate angular position of the paddle from outside the air duct, even when the duct is covered with a layer of insulation. No tools are needed to install or adjust the paddle, other than a drill to make a hole in the side of the air duct. In addition, the device is made entirely of molded plastic parts. Therefore, the present invention improves on the prior art by teaching a device that is relatively less expensive in both parts production and required labor.

A primary objective inherent in the above described apparatus and method of use is to provide advantages not taught by the prior art.

Another objective is to provide an air duct damper that has advantages in installation and use not taught by the prior art.

A further objective is to provide such an air duct damper that is convenient to install from one side of the duct rather than requiring access to both sides of the duct.

A further objective is to provide such an air duct damper that is adjustable without removing or disturbing the duct insulation.

A further objective is to provide such an air duct damper that is able to be seen in dim light and not easily covered up by duct insulation.

A further objective is to provide such an air duct damper that can be mounted in an air duct and tightened in place, without using any tools.

A further objective is to provide such an air duct damper that is made entirely out of molded plastic parts.

A further objective is to provide such an air duct damper that has a bar handle that enables for manual adjustment of the angular position of the paddle from outside the air duct without using any tools.

A still further objective is to provide such an air duct damper where the same bar handle allows for the identification of the approximate angular position of the paddle from outside the air duct, even when the duct is covered with a layer of insulation.

Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the presently described apparatus and method of its use.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Illustrated in the accompanying drawing(s) is at least one of the best mode embodiments of the present invention In such drawing(s):

FIG. 1 is a perspective exploded view of the present invention showing an air duct with a proximal portion removed so as to show interior details;

FIG. 2 is a perspective view of the present invention assembled outside of an air duct for illustrative purposes;

FIG. 3 is a perspective view of the bushing portion of the present invention;

FIG. 4 is a perspective view of the handle portion of the present invention;

FIG. 5 is a cross-sectional view of the knob portion of the present invention; and

FIG. 6 is a cross-sectional view of the bushing portion of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The above described drawing figures illustrate the described apparatus and its method of use in at least one of its preferred, best mode embodiment, which is further defined in detail in the following description. Those having ordinary skill in the art may be able to make alterations and modifications to what is described herein without departing from its spirit and scope. Therefore, it must be understood that what is illustrated is set forth only for the purposes of example and that it should not be taken as a limitation in the scope of the present apparatus and method of use.

Described now in detail is a damper device for use with an air duct 5 and other types of fluid flow conduits. The damper device is made up of a damper paddle 30, a paddle axle 20, a handle 10, a knob 40, and a tubular bushing 50 as clearly shown in FIG. 1. Each one of the components is a molded plastic part; however, other materials may be substituted in this application. Paddle 30 and axle 20 are molded as a unitary part but may be connected in other ways. Axle 20 extends distally from, and in a common plane with paddle 30.

As shown in FIGS. 3 and 6, bushing 50 provides a bushing head 54 at a proximal end and a bushing body 58 extending distally from bushing head 54. Bushing body 58 has external threads 58A, which may be a machine thread and may cover all or part of bushing body 58. Bushing body 58 is coaxially engaged with axle 20. At the distal end of bushing 50, are axially oriented, separate bushing fingers 52 which each terminate distally with a inwardly extending tip 52A. As shown in FIG. 1, axle 20 has a portion 22 at a reduced diameter which receives tips 52A thereby removably securing the bushing 50 to axle 20 at a location dictated by portion 22. In addition, axle 20 provides two flexible rubber O-rings 26 which are of a slightly larger diameter than axle 20 so that there is a frictional relationship between axle 20 and bushing 50 so that axle 20, with paddle 30 requires a selected minimum force to rotate. In the preferred application it is impossible for an air stream alone, to force paddle 30 into a new rotational position once manually set.

Knob 40 is threaded onto bushing body 58 and therefore axially movable along threads 58A. Bushing head 54 provides a head surface 56 directed toward paddle 30. Head surface 56 contains radial steps 56A, each one of which is a step in a contour of head surface 56, providing a means for engaging a peripheral edge 32 of paddle 30. With the peripheral edge 32 manually placed into contact with the radial steps 56A, bushing 50 is prevented from turning, thus allowing knob 40 to be tightened onto bushing 50 without the latter turning. As shown in FIG. 6, bushing 50 provides a tapered surface 58B between bushing head 54 and threads 58A for locking knob 40 on bushing 50. In addition, as shown in FIG. 5, knob 40 further provides a circular recess 46 which flexes outwardly as knob 40 is engaged with tapered surface 58B, thereby producing radial compressive forces for securing knob 40 in place. Thus, once knob 40 is threadably engaged with bushing 50, the two parts lock together and rotate about axle 20 as a single unit. After tightening, paddle 30 is moved laterally out of contact with head surface 56 and its radial steps 56A so that paddle 30 is free to rotate within bushing 50.

Axle 20 extends distally beyond bushing body 58, terminating with a D-shaped axle end 24. Handle 10, shown in detail in FIG. 4, has a correspondingly-sized D-shaped handle hole 12 that fits the D-shaped axle end 24. Axle end 24 is also axially slotted so that it can be compressed, enabling it to enter handle hole 12, thereby snapping handle 10 into place on axle 20. Once engaged, the D shape enables handle 10 for rotation and adjustment of the position of paddle 30. Handle 10 is in fixed alignment with the orientation of the peripheral edge 32 of paddle 30, as shown in FIG. 2. Thus, regardless of the angular position of paddle 30, handle 10 will always reflect that angular position. In addition, knob 40 preferably provides eight angularly spaced apart radial markers 44, as shown in FIG. 1, with each marker 44 being spaced 45° apart and radially positioned around axle 20. Handle 10 also contains an axial slot 14 extending linearly down one side. This slot 14 may be used to hold a flag (not shown), such as a ribbon or other similar material, allowing for identification of the approximate angular position of paddle 30, as well as the location of the present invention itself when it is positioned within the air duct 5, as discussed below.

When in use, paddle 30 is positioned within the air duct 5, with axle 20 extending through a mounting hole 5H located on a wall 5W of the air duct 5, as shown in the exploded view of FIG. 1. Bushing head 54 is positioned against an inner surface 5A of the air duct 5, and knob 40 is then threaded onto bushing body 58 until an end surface 42 of knob 40, best seen in FIGS. 2 and 5, engages with an outer surface 5B of the air duct 5. Thus, wall 5W is tightly sandwiched between head 54 and end surface 42, creating an airtight seal. Handle 10 and the markers 44 cooperate, as handle 10 is rotated, to identify the approximate angular position of paddle 30 from outside the air duct 5, even when the duct 5 is covered with a layer of insulation. Slot 14 can also operate to identify the approximate angular position of paddle 30 from outside the air duct 5, as discussed above.

The enablements described in detail above are considered novel over the prior art of record and are considered critical to the operation of at least one aspect of the apparatus and its method of use and to the achievement of the above described objectives. The words used in this specification to describe the instant embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification: structure, material, or acts beyond the scope of the commonly defined meanings. Thus if an element can be understood in the context of this specification as including more than one meaning, then its use must be understood as being generic to all possible meanings supported by the specification and by the word or words describing the element.

The definitions of the words or drawing elements described herein are meant to include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same function in substantially the same way to obtain substantially the same result. In this sense it is therefore contemplated that an equivalent substitution of two or more elements may be made for any one of the elements described and its various embodiments or that a single element may be substituted for two or more elements in a claim.

Changes from the claimed subject matter as viewed by a person with ordinary skill in the art, now known or later devised, are expressly contemplated as being equivalents within the scope intended and its various embodiments. Therefore, obvious substitutions now or later known to one with ordinary skill in the art are defined to be within the scope of the defined elements. This disclosure is thus meant to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, what can be obviously substituted, and also what incorporates the essential ideas.

The scope of this description is to be interpreted only in conjunction with the appended claims and it is made clear, here, that each named inventor believes that the claimed subject matter is what is intended to be patented.

Claims

1. A damper apparatus for controlling air flow within an air duct, the apparatus comprising:

an axle engaging a paddle, the axle extending distally from the paddle in a common plane with the paddle, a distal portion of the axle providing an axially oriented slot and a D-shaped cross section;

a tubular bushing frictionally engaged with the axle, the bushing providing a proximal head and distal external threads, the bushing frictionally engaged with axle;

a knob threadedly engaged on the bushing; and

a handle providing a D-shaped handle hole engaged with the D-shaped cross section distal portion of the axle.

2. The apparatus of claim 1 wherein the distal end of the bushing provides a plurality of axially oriented, separate fingers, each of the fingers terminating distally at an inwardly extending tip.

3. The apparatus of claim 2 wherein the axle provides a distal reduced diameter portion, the fingers engaged therewith.

4. The apparatus of claim 1 wherein the axle provides at least one flexible rubber O-ring, the at least one O-ring of a diameter as to create rotational resistance between the axle and the bushing.

5. The apparatus of claim 1 wherein the bushing provides a tapered surface between the head and the external threads, the knob engaging the tapered surface for locking the knob on the bushing.

6. The apparatus of claim 1 wherein the proximal head of the bushing provides radial steps engagable with a peripheral edge of the paddle.

7. The apparatus of claim 1 wherein the handle provides an axial slot.

8. The apparatus of claim 1 wherein the knob provides a plurality of angularly spaced apart radial markers, the handle and the markers cooperating to identify the approximate angular position of the paddle.

9. The apparatus of claim 5 wherein the knob provides a circular recess wherein with the knob engaged with the tapered surface of the bushing, an inner wall of the circular recess flexes outwardly, thereby producing radial compressive forces for securing the knob in place.

10. A combination damper apparatus for controlling air flow, the apparatus comprising:

an air duct;

an axle engaging a paddle, the axle extending distally from the paddle in a common plane with the paddle, a distal portion of the axle providing an axially oriented slot and a D-shaped cross section;

a tubular bushing frictionally engaged with the axle, the bushing providing a proximal head and distal external threads, the bushing frictionally engaged with axle;

a knob threadedly engaged on the bushing;

a handle providing a D-shaped handle hole engaged with the D-shaped cross section distal portion of the axle; and

the air duct providing a damper mounting hole in a side wall of the air duct, the paddle positioned within the air duct, the axle extending through the mounting hole, the bushing head positioned against an inner surface of the air duct, and the knob engaged with an outer surface of the air duct for securing the paddle within the air duct.

11. The apparatus of claim 10 wherein the distal end of the bushing provides a plurality of axially oriented, separate fingers, each of the fingers terminating distally at an inwardly extending tip.

12. The apparatus of claim 11 wherein the axle provides a distal reduced diameter portion, the fingers engaged therewith.

13. The apparatus of claim 10 wherein the axle provides at least one flexible rubber O-ring, the at least one O-ring of a diameter as to create rotational resistance between the axle and the bushing.

14. The apparatus of claim 10 wherein the bushing provides a tapered surface between the head and the external threads, the knob engaging the tapered surface for locking the knob on the bushing.

15. The apparatus of claim 10 wherein the proximal head of the bushing provides radial steps engagable with a peripheral edge of the paddle.

16. The apparatus of claim 10 wherein the handle provides an axial slot.

17. The apparatus of claim 10 wherein the knob provides a plurality of angularly spaced apart radial markers, the handle and the markers cooperating to identify the approximate angular position of the paddle.

18. The apparatus of claim 14 wherein the knob provides a circular recess wherein with the knob engaged with the tapered surface of the bushing, an inner wall of the circular recess flexes outwardly, thereby producing radial compressive forces for securing the knob in place.