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.

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.