Abstract:
An air duct plug is provided for obturating an open end of an air duct during periods of nonuse to prevent or limit the escape of cooled or heated air through said air duct, in a dwelling, public building or structure thereof. The plug further provides a depending handle for ease of removal from the air duct when it is determined that said air duct should be used.

Description:
FIELD OF SEARCH 
     52/2; 52/126.2; 52/302; 52/309.4; 52/309.15; 138/89.1-89.4; 52/39; 439/450; 98/56; 222/562; 222/563; 220/215; 220/226; 220/307; 220/361; 138/40; 138/89; 222/544; 222/545; 222/548; 222/554; 222/556; 222/557; 126/49; 126/319; 138/96. 
     CROSS REFERENCES U.S. PATENT DOCUMENTS 
     3,078,879, 4/1958 Mallard . . . 138/96; 3,574,312, 2/1969, Miller . . . 138/96; 3,578,027, 7/1969, Zopfi . . . 138/89; 3,821,969, 5/1972, Sinko . . . 138/89; 3,847,183, 11/1972, Meyer . . . 138/96; 4,194,494, 11/1977, Wagner . . . 126/319; 4,649,896, 8/1985, Formosa . . . 126/319; 4,762,115, 8/1987, Penner . . . 126/319. 
     BACKGROUND OF THE INVENTION 
     The change of season facillitates the need to temporarily obturate a ventillation duct to prevent or limit the escape of cooled or heated air introduced into a dwelling by its respective system. 
     To date, there is not one product on the market that will obturate the open end of a ventillation duct and provide both an airtight seal and highly insulative qualities. 
     Heretofore occupiers of dwellings with heating and cooling or ventillation systems would commonly use whatever is handy, i.e., rags, towels, blankets, plastic sheeting or protective covers. None of these methods provide the same level of sealing and insulative qualities along with ease of installation, removal, and protection from damage to the ventillation duct and its immediate surrounding area. 
     SUMMARY OF THE INVENTION 
     The present invention, by providing a plug having a body slightly larger than the aperture to be obturated, is substantially comprised of a resilient material for ease of installation and producing a secure fit by way of a frictional and compressive engagement of the outermost surface of the plug body with the internal surface of the air duct to be obturated. 
     The many objects and advantages of the present invention will become apparent to those skilled in the art when the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, wherein like reference numerals refer to corosponding parts: 
     FIG. 1 represents a side view of the embodiment of a plug according to the present invention with a portion broken away; 
     FIG. 2 represents a top view of the embodiment of the invention shown in FIG. 1; 
     FIG. 3 represents a bottom view of the embodiment of the invention shown in FIG. 1; 
     FIG. 4 represents a pictorial view of the embodiment of the invention shown in FIG. 1; 
     FIG. 5 represents a schematic view of an air duct employing a preferred embodiment of the present invention in an active position with a portion broken away; 
     FIG. 6 represents a sectional view thereof as seen from line 6--6 of FIG. 2; 
     FIG. 7 is a pictorial view of the present invention in an alternative embodiment; and 
     FIG. 8 is a pictorial view of yet another alternative embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIGS. 1-6, a plug according to the present invention takes the form of a relatively solid body 11, substantially cylindrical in shape and made of a resilient material, such as polyurethane foam of the like. Immediately contiguous to the top side of the plug body 11, is a supporting base 12, with an adjoining reinforcement ring 13. Both supporting base 12 and reinforcement ring 13 are made of a relatively rigid plastic material such as ABS or the like, and serve to support the plug body 11, during removal of the embodiment from an air duct. 
     The plug of the invention is used to obturate an aperture of any diameter within a predetermined range. For example, a plug of the invention can be used, as schematically illustrated in FIG. 5, for closing the preferred open end of an air duct, such as shown at 10, in a temporary manner. A ceiling structure 18, is also shown, having a cylindrical air duct 10 surrounded by insulation 19, with the preferred embodiment of the invention inserted in an active position inside air duct 10. 
     In the preferred embodiment, body 11 is cut from lightweight but highly insulative polyurethane foam. Thus, body 11 is of an appropriate thickness to provide adequate insulation for the prevention of heated air or cooled air loss through an air duct when the embodiment is in the active position as seen in FIG. 5. 
     Because the plug body 11 is originally of a greater diameter than the aperture of the air duct 10 to be obturated and is made of a resilient material, when the plug body 11 is compressed and forced into the open end of an air duct 10, the plug body 11 is caused to expand within the air duct 10, thus providing a frictional engagement between the cylindrical surface 9 of the plug body 11, and the inner cylindrical surface 8 of the air duct 10, promoting a secure fit until such time that it is deemed practical and proper for removal of said plug. 
     As seen in FIG. 6, running vertically through the center of the embodiment of the present invention is a rope like cord 15, secured at both ends by non fraying knots 14 and 17 respectively. Adjoining the cord 15 at the bottom end adjacent to the bottom knot 17, is a graspable handle 16, made of any rigid, solid or hollow, natural or man made material. The cord 15 serves as a means to attach said graspable handle 16 to the reinforcement ring 13 and supporting base 12, to allow for easy removal of the embodiment from an air duct. 
     Removal of the preferred embodiment is achieved by grasping handle 16 and pulling with sufficient force which will be transmitted from knot 17 through cord 15 to top knot 14 which in turn produces sufficient force axially on reinforcement ring 13 and support base 12 to extract plug body 11 from air duct 10. 
     An alternative embodiment of the present invention is illustrated in FIG. 7 where suffix &#34;a&#34; has been added to describe elements similar to those described in connection with the first embodiment of the invention. Air duct plug 11a is similar in structure and function to air duct plug 11 and is used for air ducts having a square shape. Body 11a is similarly shaped like a short box so as to permit walls 9a to be complimentary to the inside wall of a square air duct and produce an even fit along with adequate sealing. Handle 16a, support structure, 13a connected integrally with 12a, along with a connecting means 15a, provide a means for easy removal. 
     Yet another alternative embodiment of the present invention for use with air ducts having a rectangular shape is shown in FIG. 8. Suffix &#34;b&#34; will be used to describe elements similar to those described in connection with the first embodiment of the invention. The body 11b and walls 9b are substantially rectangular in shape so that said body 11b and walls 9b may fit tightly and evenly in rectangular air ducts. Support structure, 13b and 12b respectively, is also rectangular in shape to compliment the shape of the air duct to be obturated, and provide an even distribution of force when the embodiment is to be removed from said rectangular air duct. 
     As can be seen by the above descriptions, the present invention provides a product that is lightweight, uncomplicated, economical to manufacture, and of value to the public at large. 
     It will, of course, be understood that modifications of the present invention, and its various aspects, will be apparent to those skilled in the art, some being apparent only after study, and others merely matters of routine mechanical design. As such, the scope and the invention itself, should not be limited by the particular imbodiments and specific constructions herein described, rather the invention should be defined only by the appended claims, and equivalents thereof.