Patent Publication Number: US-6668487-B2

Title: System and method for applying an animal access door to an inclined surface

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to animal access doors of the type that enable a pet dog or cat to enter or exit a building unassisted. More particularly, the present invention relates to the structure of animal access doors and the methods of installing such animal access doors to different surfaces. 
     2. Description of the Prior Art 
     The prior art record is replete with different types of animal access doors. The simplest animal access doors are just small openings that are cut through the door or wall of a house so that a dog or cat can enter or exit the house at will. The cut opening is typically covered by a flap that can be swung open by the pet as the pet passes through the opening. A problem associated with such swinging flap animal access doors is that they enable strange animals or wild animals access to the house. Furthermore, such swinging door access openings do little to keep out bad weather and wind. Rather, such swinging flap animal access doors rely upon their vertical orientation to keep the flap closed and the weather out. Consequently, such swinging flap animal access doors are typically applied to house doors that have some type of overhang protection to keep weather from directly bearing on the surface of the door. 
     To help prevent strange animals or wild animals from entering animal access doors, high-tech animal access doors have been developed. Such high-tech animal access doors only open or unlock when a specific pet approaches the animal access door. Such animal access doors contain sensors that detect a magnet or signal emitter that is carried on the collar of the pet. As the pet approaches the door, the collar on the pet is detected and the animal access door briefly opens or unlocks. Such prior art animal access doors are exemplified by U.S. Pat. No. 4,991,350, to Kirk, entitled Electromagnetically Controlled Cat Flap. 
     Since very few pets are trained to close doors, both hanging flap access doors and high tech access doors typically rely upon gravity to close the door after the animal has passed. Consequently, such animal access doors must be applied to vertical surfaces so that gravity will return the animal access door to a vertical position. However, there are many surfaces in a house that are not vertical. One such surface is an inclined cellar door. Inclined cellar doors are typically used to cover external stairways that lead directly to the cellar of a home from the outside. Inclined cellar doors are popular with many homeowners because they provide a large access port to the cellar that enables large objects, such as boilers, water heaters, pool tables and the like to be more readily moved into and out of the cellar. 
     Many pet owners keep their pets in their cellars. It would be highly desirable for a home to have a pet access door that leads directly from the cellar to the outside. However, conventional animal access doors cannot be applied to inclined cellar doors. If they were, they would not close and would allow weather and strange animals to enter the cellar. Furthermore, the unclosed animal access door at the top of the cellar stairwell would present a falling hazard to children and unwary animals. 
     A need therefore exists for a new animal access door that is adapted to be applied to an inclined surface, such as an inclined cellar door, wherein the animal access door keeps out the weather and does not present a falling hazard. This need is met by the present invention as described and claimed below. 
     SUMMARY OF THE INVENTION 
     The present invention is a system and method for applying an animal access port to an inclined surface, such as an inclined cellar door. The system includes rail elements that are applied to the inclined surface on either side of an opening that has been cut through the inclined surface. The rail elements create tracks along the sides of the opening. A dormer structure is provided. The dormer structure has walls and a top surface that spans the walls to define an interior space within the dormer structure. However, the dormer structure has no bottom surface, and is thus open at its bottom. One of the walls of the dormer structure supports a door. The dormer surface can be placed in the tracks created by the rail elements. The tracks retain the dormer structure in place over the opening in the inclined surface. The dormer structure protects the opening in the inclined surface and provides access to the opening through the door in the wall of the dormer structure. 
     The dormer structure can be selectively removed from the track of the rail elements. In its place, a solid plate can be positioned, using the track of the rail elements. The result is a solid cover that protects the opening in the inclined surface from any access. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the present invention, reference is made to the following description of an exemplary embodiment thereof, considered in conjunction with the accompanying drawings, in which: 
     FIG. 1 is an exploded perspective view of an exemplary embodiment of the present invention system being applied to an inclined cellar door; 
     FIG. 2 is a cross-sectional view of the embodiment of the dormer structure shown in FIG. 1 as installed on an inclined cellar door; and 
     FIG. 3 is a perspective view of the embodiment of the safety panel shown in FIG. 1 as installed on an inclined cellar door. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Although the present invention animal access door system can be applied to any inclined surface, such as a roof, the present invention is particularly well suited for application to an inclined cellar door. As such, the present invention animal access door system will be described and illustrated as being applied to an inclined cellar door in order to set forth the best mode contemplated for the invention. 
     Referring to FIG. 1, a typical inclined cellar door  11  is shown. Such inclined cellar doors commonly cover stairwells that lead directly into the cellar of a home. Inclined cellar doors are typically manufactured of steel, however, in older homes wooden inclined cellar doors can still be found. An opening  13  is cut into the inclined cellar door  11  over the first step of the stairwell. The size of the opening  11  is dependent upon the size of the pet that will be passing through the opening  13  and the size of the animal access door system  10  selected. 
     The present invention animal access door system  10  is a modular system that consists of multiple interconnecting components. Guide rails  12  are attached to the inclined cellar door  11  on either side of the opening  13 . A stop rail  14  is also positioned between the guide rails  12  at the bottom most edge of the opening  13 . The guide rails  12  create tracks  16  on the exterior of the inclined cellar door  11  along the sides of the opening  13 . Either a dormer structure  20  or a safety panel  30  can be placed into the tracks  16  over the opening  13 . The dormer structure  20  is used when access to the opening  13  is to be provided to a pet. The dormer structure  20  can be removed and replaced with a safety panel  30  if no pet is to be provided, or if the family and pet are away on vacation. 
     From FIG. 1, it can be seen that the dormer structure  20  has lip extensions  22  that pass into the tracks  16  that are created by the guide rails  12  on either side of the opening  13 . The protruding lip extensions  22  pass into the tracks  16  from the top of the tracks  16 . The protruding lip extensions  22  advance along the tracks  16  until they abut against the stop rail  14  at the bottom of the opening  13 . Once at this location, the dormer structure  20  is symmetrically disposed over the opening  13  in the inclined cellar door  11 . The engagement of the lip extensions  22  on the dormer structure  20  with the track  16 , prevents the dormer structure  20  from moving in any direction other than back out along the plane of the tracks  16 . 
     The dormer structure  20  is a four sided structure having no bottom and an inclined top surface  24 . The slope of the top surface  24  of the dormer structure  20  is opposite the direction of the slope of the inclined cellar door  11 . The four side walls of the dormer structure are vertical and remain vertical even when the dormer structure  20  is attached to the inclined cellar door. A flap door  26  is present in the front wall  28  of the dormer structure  20 . The flap door  26  covers an access opening through which a pet can pass. 
     Referring to FIG. 2, it can be seen that the dormer structure  20  and the opening  13  in the inclined cellar door  11  are positioned over the first step  15  of the cellar stairwell. The flap door  26  on the front wall  28  of the dormer structure  20  is hung from its top with a hinge that enables the flap door  26  to swing either into or out of the dormer structure  20 . As a pet approaches the dormer structure  20 , the pet pushes against the flap door  26 . The flap door  26  swings open and the pet can either enter or exit the cellar stairwell through the dormer structure  20 . The top surface  24  of the dormer structure  20  may overhang the flap door  26  to protect the flap door  26  from rain. 
     Since the flap door  26  is small and vertical, is highly unlikely that a child would be able to fall though the flap door  26  and then through the opening  13  in the inclined cellar door  11 . As such, the presence of the dormer structure  20  prevents a child or animal from accidentally stepping on the inclined cellar door  11  and falling through the opening. 
     The flap door  26  can be just a free hanging door or a door that closes with a weak magnetic seal. However, the technology of prior art animal access doors can be applied to the flap door  26  in the dormer structure  20 . The dormer structure  20  can be supplied with an electromechanical locking mechanism  29  that locks the flap door  26  closed. The electromechanical locking mechanism  29  can be controlled by a sensor  31  located on the dormer structure  20 . The sensor  31  can detect the presence of a specialized pet collar  33  worn by a pet. The pet collar  33  can contain a magnet, transmitter or the like that can be detected by the sensor  31  when in close proximity to the sensor  31 . Once the sensor  31  detects the pet&#39;s collar, the sensor  31  activates the electromechanical locking mechanism  29  and enables the pet wearing the collar  33  to pass into or out of the dormer structure  20 . 
     The dormer structure  20  can be selectively removed from above the opening in the inclined cellar door  11 . Referring to FIG. 3, it can be seen that once the dormer structure  20  is removed, a safety panel  30  can be placed over the cellar door opening  13 . The safety panel  30  slides into the tracks  16  created by the guide rails  12 . In the safety panel  30  is located a locking aperture  34 . When the safety panel  30  is fully advanced into the tracks  16  of the guide rails  12 , the locking aperture  34  aligns with a breach  36  in the guide rail  12 . At this point, a locking pin or padlock  38  can be advanced through the locking aperture  34  and breach  36 . Once in place, the padlock  38  would prevent the safety panel  30  from being removed by any unauthorized person. Although not illustrated, it should be understood that the locking aperture  34  present in the safety panel  30  can also be present in the protruding lip extension  22  (FIG. 1) of the dormer structure  20 . As such, the dormer structure  20  can be locked into place in the same manner as the safety panel. 
     The safety panel  30  can be metal or any other material that is strong enough to withstand a person&#39;s weight who may stand on the safety panel  30  over the opening in the inclined cellar door  11 . 
     Returning to FIG. 1, it will now be understood that to install the present invention system  10 , the system  10  is first purchased from a retailer. The size of the dormer structure  20  provided in the system  10  will be dependent upon the size of the pet that will be utilizing the system  10 . Initially three sizes will be available, large, for large dogs, medium, for medium sized dogs and small for small dogs and cats. Provided in the purchased systems will be the guide rails  12 , the dormer structure  20  and the safety panel  30 . Also provided will be instructions of how large of an opening  13  must be cut in the inclined surface prior to the installation of the system  10 . Once the opening is cut, the guide rails  12  are installed using screws and/or bolts. The dormer structure  20  or the safety panel  30  can then be set into place as needed. 
     In the embodiment shown in FIG. 1, FIG.  2  and FIG. 3, the dormer structure  20  was attached to the inclined cellar door  11  utilizing the guide rails  12 . The guide rails  12  create tracks. In this manner, the dormer structure  20  can be selectively removed and replaced with a safety panel  30  without tools. However, such a configuration is merely exemplary. It should be understood that the dormer structure  20  can be directly attached to the inclined cellar door  11  using nails, bolts and/or adhesive. In such a construction, the dormer structure would be permanently set in place and would not be replaceable with a safety panel. Consequently, mechanical fasteners, such as nails, screws and bolts can be considered attachment mechanisms for directly attaching the dormer structure  20  to an inclined cellar door. Furthermore, adhesives should also be considered attachment mechanisms for attaching the dormer structure  20  to the inclined cellar door. Accordingly, the rail guides  12 , mechanical fasteners and adhesives are all attachment mechanisms within the meaning of the term set forth below in the claims. 
     It will also be understood that the embodiment of the present invention system illustrated and described is merely exemplary and that a person skilled in the art can make many modifications to the specific features shown. For example, the shape and size of the dormer structure can be altered in many different ways. The dormer structure can have any shape and be any size provided the dormer structure covers the opening in the cellar door and provides a vertical door to enter and exit the dormer structure. Furthermore, the flap door used in the dormer structure can be altered into a wide variety of shapes and a wide variety of locking mechanisms can be used to close the flap door. Many known prior art animal access doors and locking mechanisms can be adapted for use with the dormer structure of the present invention. Lastly, many different locking mechanisms can be used to lock the dormer structure or the safety panel in place. Any prior art device for locking an element in a track can be adapted for use with the present invention.