Patent Abstract:
An access panel for an opening in a duct is provided. The access panel includes an exterior and an interior. The access panel further includes a section positioned on the interior and having a profile substantially corresponding to the opening in the duct. A plurality of fasteners is positioned about the section. Each fastener has a clip configured to move to a position defined to extend away from the profile of the section on the interior. When the access panel is positioned with the section on the interior against the opening in the duct and the fasteners are moved to the locking position the clips rotate to extend over the profile and secure a portion of the duct adjacent to the opening against the interior of the access panel.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation in part of U.S. application Ser. No. 13/670,653 filed Nov. 7, 2012. 
    
    
     BACKGROUND OF THE INVENTION 
     The background of the invention relates to a duct access door. Typically to clean or inspect a duct or a portion thereof, a technician cuts a portion of the duct out. After inspecting and/or cleaning the technician would place the cut out portion over the hole and tape it back in place. While this may be solve the current problem there a numerous disadvantages with this approach. First, the technician may not tape the portion back entirely, leaving gaps or spaces between the opening in the duct and the resealing thereof. Second, after a while the tape can begin pealing away from the duct exposure portion of the duct to dust and dirt. Third, in industrial and commercial businesses duct inspection and cleaning occurs more frequent then in residential arrears. To reopen the duct the technician has to cut away the tape and then re-seal, often leaving further issues and problems that are not visual to the technician but may occur afterwards. Forth, cutting away a portion of the duct often leaves sharp corners that can easily cut a technician arms and hands. Fifth, other products on the marks have loose parts such as nuts or bolts that can be easily lost or misplaced, often times left in the duct itself. 
     There is thus a need to provide an easy and simply solution that provides easy access to the duct, especially for future use. 
     SUMMARY OF THE INVENTION 
     One or more of the embodiments provided in the present invention relates to an access panel for an opening in a duct system. The access panel includes a base plate having an exterior surface side and an interior surface side. The base plate when positioned in the opening of the duct system has the interior surface side facing the duct system and the exterior surface side facing away from the duct system. The access panel also includes a section positioned on the interior surface side that has a profile substantially corresponding to the opening in the duct system. In addition, a plurality of rotatable fasteners are positioned about the section. Each fastener has a locking clip configured to move to a locking position defined to extend over the profile of the section on the interior surface side. As such, when the access panel is positioned with the section on the interior surface against the opening in the duct system and the plurality of rotatable fasteners are moved to the locking position the locking clips rotate to extend over the profile and secure a portion of the duct system adjacent to the opening against the interior surface side of the access panel. 
     In additional aspect of this embodiment, the access panel may include a handle secured to the exterior side. To further help create a better seal between the duct an access panel, a gasket may be positioned on the interior surface side of the base plate, the gasket being further positioned between a terminus end of the interior surface side and the plurality of fasteners. In addition, the access panel may further include a rope seal positioned between the terminus end and outer side of the gasket. 
     The fasteners may be configured to include (i) a bottom plate secured to the interior surface side of the access panel, (ii) a rotatable cylinder having a front face positioned through the bottom plate and base plate of the access panel such that the front face is accessible from the exterior surface side of the access panel, (iii) a support flange extending from an edge of the bottom plate to a rear face portion defined on the cylinder, and (iv) a locking clip secured to the cylinder and rotatable therewith, the locking clip having a portion that is configured to move into engagement over a portion of the gasket when the cylinder rotates. As such, when the access panel is positioned with the section on the interior surface against the opening in the duct system and the plurality of rotatable fasteners are moved to the locking position the locking clips move into engagement against a portion of the duct system adjacent to the opening to secure the same against a portion of the gasket. The front face of each cylinder may include a key head or a knurl head. 
     Numerous other advantages and features of the invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims, and from the accompanying drawings. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       A fuller understanding of the foregoing may be had by reference to the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of an access panel used to secure against an opening in a duct system; 
         FIG. 2  is a perspective view of an interior side of the access panel from  FIG. 1 ; 
         FIG. 3  is a perspective view of an interior side of an access panel in accordance with another embodiment of the invention; 
         FIG. 4  is a top view of a fastener used to secure the access panel against the duct system; 
         FIG. 5  is a top view of the fastener in the locking position; 
         FIG. 6A  is a perspective view of the fastener; 
         FIG. 6B  is a perspective view of a fastener in accordance with another embodiment of the invention; 
         FIG. 7A  is a perspective view of the access panel using knurl handles to lock the fastener; 
         FIG. 7B  is a perspective view of an access panel using a screw driver to lock the fastener; 
         FIG. 7C  is a side view of an access panel with the fastener from  FIG. 6B ; 
         FIG. 7D  is a top view of a fastener knurl handle in accordance with another embodiment of the invention; 
         FIG. 8  is a template sticker used in a method of installing an access panel; 
         FIG. 9  is a perspective view of the template being attached to a duct system; 
         FIG. 10  is a perspective view of the template being cut out of the duct system to create an access opening; 
         FIG. 11  is a perspective view showing the access opening as the template and portion of the duct system under the template is removed; 
         FIG. 12  is a perspective view showing an access panel being positioned over the opening; 
         FIG. 13  is a side view of the access panel being positioned towards the opening in the duct system; 
         FIG. 14  is a side view of the access panel secured against the duct system covering the opening therein; 
         FIG. 15  is a side view of an access panel secured against the duct system having extended bolts to secure insulation on the exterior of the panel; 
         FIG. 16  is a top view of the access panel from  FIG. 15 ; and 
         FIG. 17  is an access panel in accordance with one embodiment of the present invention providing for a curved duct system. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     While the invention is susceptible to embodiments in many different forms, there are shown in the drawings and will be described herein, in detail, the preferred embodiments of the present invention. It should be understood, however, that the present disclosure is to be considered an exemplification of the principles of the invention and is not intended to limit the spirit or scope of the invention and/or the embodiments illustrated. 
     Referring now  FIGS. 1 and 2  there is provided an access panel  100  for use with in a duct system found in any residential, commercial or industrial areas. The access panel  100  has a base plate with an exterior side  102  and an interior side  104 . The interior side  104  would face the duct, while the exterior side  102  would in turn face away from the duct. A handle  106  could be positioned on the exterior side  102  to allow the technician easy means of holding the access panel  100  when installing or removing it from the duct. A plurality of fasteners  108  (or cam locks), explained in greater detail below, are also provided in the access panel  100  and provides a means for securing the access panel  100  to an edge portion of the opening in the duct. 
     The interior side  104  of the access panel  100  may include a gasket  110  positioned between a terminus end  112  of the interior side  104  and the plurality of fasteners  108 . In various aspects of the present invention the gasket  110  may be made from neoprene and act as a dust gasket preventing dust, particles, or gas from inside the duct from escaping. 
     Referring now also to  FIG. 3 , in other aspects of the present invention a rope seal  114  may be positioned between the terminus end  112  of the interior side  104  and an edge  116  of the gasket. The rope seal  114  may be made from a fiberglass rope material and rated to withstand at a predetermined temperature, such as above 1400° F. to help contain a duct fire. Higher temperature ratings may be used, such as 2100° F., to increase the safety factor. 
     In another embodiment of the present invention, the access panel  100  can have a octagonal profile  118  helping to reduce sharp corners when cutting the duct opening. 
     Referring now to  FIGS. 4 through 7B , The fasteners  108  or cam locks each include a bottom plate  120  secured to the interior side  104  of the access panel. A cylinder  122  is positioned through the base plate  120  and through an aperture (not shown) in the access panel, such that a front face  124  of the cylinder  122  is accessible from the exterior side  102  of the access panel. An L shaped support flange  126  extends from an edge of the bottom plate  120  to a rear face portion  128  of the cylinder. The cylinder is rotatable with respect to the bottom plate  120  and support flange  126  and the cylinder includes a clip  130 . The clip  130  has a first edge secured about the rear face portion  128  and a second edge secured about a portion of the cylinder adjacent the bottom plate  120 , such that when the cylinder rotates, the clip rotates therewith. Lastly, the clip  130  includes a locking section  132  that when the cylinder is rotated, moves into engagement over the gasket such that when the access panel  100  is positioned over an opening  315  in the duct  150 , the locking section  132  secures a portion  155  of the duct  150  adjacent the opening against the gasket  110 . Similarly rotation of the cylinder is an opposite direction can disengage the clip. 
     While the front face  124  of the cylinder  122  may include a key head to permit rotation of the cylinder by a key, tool, wrench, screwdriver ( FIG. 7B ) or similar devices, the front face  124  may also include a knurl head  140  that allows a technician to engage and disengage each clip by simply turning the knurl head and thus rotating the cylinder ( FIG. 6A ). This aspect would provide a tool-less access panel. 
     Referring now also to  FIG. 6B  and  FIGS. 7C and 7D  in other embodiments of the present invention there is provided a plurality of fasteners  108 B or cam locks; each include a bottom plate  120  secured to the interior side  104  of the access panel. A cylinder  122  is positioned through the base plate  120  and through an opening  103  in the access panel, such that a front face  124  of the cylinder  122  is accessible from the exterior side  102  of the access panel. An L shaped support flange  126  extends from an edge of the bottom plate  120  to a rear face portion  128  of the cylinder. The cylinder is rotatable with respect to the bottom plate  120  and support flange  126  and the cylinder includes a clip  130 . The clip  130  has a first edge secured about the rear face portion  128  and a second edge secured about a portion of the cylinder adjacent the bottom plate  120 , such that when the cylinder rotates, the clip rotates therewith. Lastly, the clip  130  includes a locking section  132  that when the cylinder is rotated, moves into engagement over the gasket such that when the access panel  100  is positioned over an opening  315  in the duct  150 , the locking section  132  secures a portion  155  of the duct  150  adjacent the opening against the gasket  110 . Similarly rotation of the cylinder is an opposite direction can disengage the clip. In addition, an O-ring  127  is positioned between the bottom plate  120  and the front face, preferably between the bottom plate  120  and the knurl head  140 . The O-ring  127  positions in the opening of the accesses panel to provide a fluid seal between the outside and the inside of the duct. As shown the front face  124  of the knurl head  140  may include a key head  141  to permit rotation of the cylinder by a key, tool, wrench, screwdriver or similar devices. 
     Referring now to  FIGS. 8 through 14 , there is shown a method of installing an access panel  100 , similarly designed to one or more of the aforementioned embodiments. The method includes in a first step to apply a template outline  300  to a portion of the duct  150  that matches substantially to a profile outline  145  on the interior side  104  of the access panel  100  ( FIG. 9 ). The template outline  300  may be a sticker  305  that can be pealed from a backing page  310  ( FIG. 8 ) and then easily applied to a portion of the duct  150 . Once affixed to the duct, the technician can cut around the sticker  305  to create an opening  315  matching or corresponding to the profile outline  145  ( FIGS. 10 and 11 ). As noted, in one aspect, the template outline may have a polygonal shaped profile that is less inclined to have sharp corners such as an octagon or other similar shape. The technician can then position an access panel  100  over the opening  315  and position and lock the access panel against the opening  315  in the duct  150 . By rotating the cylinders and thus engaging the clips against a portion of the duct adjacent the opening the access panel  100  will be locked in place. 
     Referring now to  FIGS. 15 and 16  there is provided in another embodiment of the present invention an access panel  400  having external stud bolts  405  to permit insulation or sound deadening material  410  to be secured to the outer face  102  of the access panel  400 . This is especially important with the duct system includes outer insulation. As such any insulation or material removed to create the access panel can be replaced after the access panel is secured to the duct. The stud bolts  405  may include a bolt  402 , wing nut  407  and a washer  409  to help secure the insulation in place. 
     As illustrated in  FIG. 17 , it is also possible to have a curved plate  502  in an access panel  500  designed to fit onto a curved duct system  550 . 
     From the foregoing and as mentioned above, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the novel concept of the invention. It is to be understood that no limitation with respect to the specific methods and apparatus illustrated herein is intended or should be inferred.

Technology Classification (CPC): 5