Abstract:
A unitary damper shaft extender for HVAC air ducts, the extender comprising a unitary apparatus comprised of two interlocked, but relatively movable members. One of the members being capable of interlocking with a damper shaft, and the second member being slidably movable to cover, and thereby lock the first member to the damper shaft, so as to extend its length beyond the usual insulation used for air ducts.

Description:
This application claims the benefit of priority pursuant to 35 U.S.C. 119(e) from a U.S. provisional patent application having Application No. 61/264,059 filed Nov. 24, 2009. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an improved extension for handle connections to air duct dampers. 
     BACKGROUND OF THE INVENTION 
     Damper assemblies in HVAC air ducts include a movable damper capable of Hocking or diverting air, or other gases, passing through the interior of the duct, intended to heat or cool the building in which it is located. It is often desirable to manually control the damper, and for this purpose a control shaft is attached to the damper and extends through an opening in the duct wall to the exterior of the duct, A handle is fitted onto the outer end of the control shaft, and is secured to the control shaft by, e.g., a nut. 
     Generally, such damper assemblies contained within short sections of a duct are assembled at the factory, to insure a close fit in the wall opening to prevent loss of air pressure and are commonly available in complete units. The control shafts on the prefabricated assemblies extend out from the outer surface of the duct only a short distance. However, it is often desirable, as an energy saving method, to have the entire length of the air duct, including the damper assembly portion, wrapped in insulation; in such a situation, usually the factory installed control shaft does not extend out beyond the insulation layer, interfering with the operation of the handle on the control shaft, to operate the damper. Many attempts have been made to simply extend the length of the shaft for the handle so that the handle can easily move beyond the thickness of the insulation. For example, two different concepts are shown in U.S. Pat. Nos. 4,646,715 and 6,035,849. They have all had the problems of undue complexity, because of the number of parts that the ultimate installer was required to handle. 
     Accordingly, it is an object of the present invention to provide a product that will simplify the end user/installer&#39;s work in adding a unitary extension to the damper apparatus that will effectively extend the control shaft of a damper assembly beyond the layer of insulation, permitting a certain amount of regulation as to the length of the control shaft. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic isometric view of the damper assembly with an extender element in accordance with the prior art; 
         FIG. 1A  shows in cross-section the prior art extender passing through an insulated wall of a duct; 
         FIG. 2  is a schematic end view of the securing member of the prior art shown in  FIG. 1 ; 
         FIG. 3  is a schematic isometric view of one part of the multi part extension member of the prior art; 
         FIGS. 4A and 4B  are longitudinal top views of the assembled extension apparatus of the present invention; showing the internal extension member in two different positions; 
         FIG. 5  is a schematic isometric view of the exterior of the damper assembly showing the original, nonextended shaft; 
         FIG. 6  is a schematic longitudinal bottom view of the assembled extender apparatus of the present invention; 
         FIG. 7  is a schematic end view of the assembled extender apparatus of the present invention; 
         FIG. 8  is a schematic longitudinal top view of the connector portion of the assembled extender apparatus of the present invention; 
         FIG. 9  is a schematic end view of the connector portion of the assembled extender apparatus of the present invention; 
         FIG. 10  is a schematic longitudinal bottom view of the collar portion of the assembled extender apparatus of the present invention; 
         FIG. 11  is a schematic end view of the collar portion of the assembled extender apparatus of the present invention; 
         FIG. 11A  is a schematic end view of a second embodiment of the collar portion of the unitary extender apparatus of the present invention; 
         FIGS. 12A , B are schematic longitudinal top views of the assembled extender apparatus of the third embodiment of the present invention, showing the two outermost positions of the extender; 
         FIG. 13  is a schematic side view of the extender portion of the third embodiment of the present invention; 
         FIG. 14  is a schematic longitudinal top view of the extender portion of the third embodiment of the assembled extender apparatus of the present invention; 
         FIG. 15  is a schematic end view of the extender portion of the assembled extender apparatus of the third embodiment of the present invention; 
         FIG. 16  is a schematic longitudinal side view of the collar portion of the assembled extender apparatus of the third embodiment of the present invention; and 
         FIG. 17  is a schematic end view of the collar portion of the unitary extender apparatus of the third embodiment of the present invention. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     In  FIGS. 1 and 1A , there is shown a damper assembly  11  in accordance with the prior art, including an extended handle shaft.  FIGS. 2 and 3 , show the two piece extender of the prior art. The damper assembly  11 , which is inserted into ductwork to control the flow of air, includes a portion or section of a duct  13 , a damper  15 , an extended control shaft  33 ,  37 , a handle  19  and a wing nut  21 . 
     The duct section  13  is of a conventional type, useful for conveying air through its interior portion and having ends that provide for coupling, at each end, for insertion into duct works, which connect between the air source and the outlets. Damper  15  is installed within the duct  13  and is so sized as to be able to block flow through the duct when in a blocking position extending transverse to the axis of the duct. The damper  15  is installed to rotate about an axis, that is perpendicular to the longitudinal axis of the duct, between the blocking and a fully open position so as to allow control over the flow of air through the duct. 
     The extended control shaft  37  is coupled to the damper  15  and is coaxial with the damper axis of rotation, and extends outwardly through an opening  23  in the wall of the duct  13  (see  FIG. 5 ). The original short control shaft  3  is generally a double truncated cylinder with a pair of parallel opposed flat keying sides  25 , and a pair of opposed arcuate sides  27  merging with and between the two opposing flat sides  25  (see  FIG. 5 ). The arcuate sides  27  are threaded for cooperating with the wing nut  21  in securing the handle. Turning the handle  19  causes the control shaft  17  to rotate. 
     The illustrated extension apparatus  33  of the prior art includes a two part extension mechanism including an outer sleeve  37  having a fully enclosed slot extending longitudinally therethrough (see  FIG. 2 ), complementary to the shape of the separate y-shaped extension member, shown in  FIG. 3 . 
     One embodiment of the present invention provides the installer with a unitary extension part  135  to be connected to the original short handle original control shaft  3 , which is shown in  FIGS. 4A  and B and  6 - 11 . The unitary extension part  135  has an outer collar portion  139  and a y-shaped shaft extender portion  141 . The extender portion  141  has two flat sides  143  that are parallel to one another and extend between an open end and a closed end. The thickness of the extender portion  141 , as measured between the flat sides  143 , is the same as that of the original control shaft  3 . The extender portion  141  has arcuate sides  145  extending between the flat sides  143 . A threaded bore  147  extends longitudinally inward from the open y-end and is sized so as to receive the outer end portion of the original control shaft  3 , which is also as shown in  FIG. 5 . 
     The y-shaped extension portion  141  is permanently slidably locked within the collar  139 , capable of sliding along a limited path along the internal bore  148  of the collar  139 . The extent of the sliding motion is shown by  FIGS. 4A-B . A longitudinal slot  149  extends through the wall of the holder  139  along the entire length of the collar  139 . The longitudinal slot  149  has a width less than the width of the bore  148 , which generally is complementary in shape, but has sufficient play to permit easy sliding of the extension portion  141  along the bore. This prevents dislocation of the extension connector  141  from out of the bore  148 . 
     Diametrically opposite to the location of the longitudinal slot  149  is a second guide slot  151 , narrower and extending along only a portion of the length of the collar  139 . A guide pin  153  is secured to the flat surface of the extension connector  141  extending radially outwardly through the guide slot  151 , limiting the longitudinal motion of the connector  141  along the bore  148 , and thus preventing the extension connector  141  from falling out from the holder  139 . 
     As shown in  FIG. 4B , at one end of its travel, the y-shaped end  147  of the connector  141  extends out of one end of the collar bore, permitting it to be connected to the original shaft  3 , extending out from the duct wall “D”. Once the y-shaped end  147  of the connector is properly connected by the threaded surface to the original shaft  3 , the collar  139  is permitted to slide down to cover the thus connected connector  141  and shaft  3 , holding them together, as shown in  FIGS. 4B and 12A . As a final step, the handle  19  is secured to the straight end  142  of the y-shaped extension connector  141 , which matches the cross-section shape of the original shaft  3 , and is secured in place by the original wing-nut  5 , as is shown in  FIGS. 1 and 1A . As shown, the wing nuts secure the handles and the collar  139  onto the connector  141 , locking the unitary extension apparatus onto the original shaft. 
     The schematic representations of the unitary connection apparatus  135 , in  FIGS. 6 and 7  show the details of the unit.  FIGS. 8 through 11  show the individual elements of the unitary apparatus. The unitary apparatus  135  is made by forming the collar  139  by machining or extrusion molding to form the bore  148  and the longitudinal slot  149  and the guide slot  151 . The holder is shown in two embodiments.  FIG. 11  is formed as a cylinder with the two slots formed along the outer wall, preferably diametrically opposite to each other. The y-shaped connector  141  is inserted into the bore  143  of the holder  135 , and the guide pin  153  is inserted into the side of the connector  141  opposite to the slot  149 , through the guide slot  151 . A threaded hole, or other connecting means, was provided in the flat connector surface  143  to receive the guide pin  153 . The guide pin  153  through plot  151  prevents the y-shaped connector  141  from sliding out from the collar  139 . This simplifies the work of the ultimate installer of the extension. 
     The third embodiment of the present invention, as shown in  FIGS. 12A-17 , provides the installer with a unitary extension part generally indicated by the numeral  235 , to be connected to the original short handle original control shaft  3 . The assembled unitary extension part  235  is shown in  FIGS. 12A and 12B . The unitary extension part  235  has a collar  239  and a y-shaped shaft extender portion  241 . The extender portion has two flat sides  243  that are parallel to one another and extend between an open end and a closed end. The thickness of the y-connector portion  241 , as measured between the flat sides  243 , is the same as that of the original control shaft  3 . A substantially rectangular raised key  349  extends from one of the flat sides of the y-connector. The connector portion  241  has arcuate sides  245  extending between the flat sides  243 . An internally threaded bore  247  extends longitudinally inward from the open y-end and is sized so as to receive the outer end portion of the original control shaft  3 , which is complementarily externally threaded as shown in  FIG. 12B . 
     The collar  239  of this third embodiment is generally cylindrical in shape with a slot  339  extending therethrough. The slot is sized to hold the y-shaped connector  241 , and has a keyslot  353  extending above the main slot  339 . When the connector part  235  is assembled, the y-connector  241  is pushed through the slot until the key  349  is centered within the collar  339 . Two dimples  349  are punched in near the ends of the collar  239  and into the key slot  353 , which serve to lock the y-connector  241  within the collar  239 , but allow sliding over a limited range, as is shown in  FIGS. 12A-B . 
     The y-shaped extension connector  241  is thus permanently slidably locked within the collar  239 , capable of sliding a limited path along the internal bore  339  of the collar  239  between the two dimples  349 . The range of the sliding motion is shown by  FIGS. 12A-B . The longitudinal bore  339  has a size and shape which generally is complementary in shape, but has sufficient play to permit easy sliding of the extension connector  241  along the bore. The dimples prevent dislocation of the extension connector  241  from out of the bore  339 . 
     As shown in  FIG. 12B , at one end of its travel, the y-shaped end  257  of the connector  241  extends out of one end of the holder bore, permitting it to be connected to the original shaft  3 , extending out from the duct wall “D”. Once the y-shaped end of the connector is properly connected by the threaded surface to the original shaft  3 , the collar  139  is permitted to slide down to cover the thus connected connector  241  and the original shaft  3 , holding them together, as shown in  FIG. 7 . As a final step, the handle is secured to the straight end  242  of the extension connector  241 , which matches the cross-section shape of the original shaft  3 , and is secured in place by the original wing-nut  5 , as is shown in  FIGS. 1 and 8 . As shown, the wing nut  5  secures the handle and the collar onto the connector  241 , locking the unitary extension apparatus onto the original shaft. 
     The schematic representations of the unitary connection apparatus  235 , in  FIGS. 12A and 12B , show the details of the unit. The collar  239  can be formed in a single step by, preferably, extrusion molding to form the collar  239  and the bore  339 , including the key slot  353 . The y-shaped connector  241 , in this third embodiment, is inserted into the bore  339  of the holder  239 , so that the key  253  is inserted into key slot  353 . The key  349  is centered within the collar  239 , and dimples  354  are punched into the outer circumference of the collar  239 , so as to flatten those portions of the key slot  353 , so that the y-connector  241  can no longer be removed from the holder. This provides even greater simplification of the work of the ultimate installer. 
     The foregoing disclosure and the showings made in the drawings are merely illustrative of the principles of this invention and are not to be interpreted in a limiting sense. The invention is properly defined only by the following claims: