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BACKGROUND OF THE INVENTION  
         [0001]    1. Technical Field  
           [0002]    The invention relates generally to the field of pet doors and is directed to a device adapted to be mounted in a window and comprising a pet-specific identification component and a powered door. More specifically, the invention is directed to an improved automatic pet door device designed to be easily installed and deinstalled in a variety of locations with only minimal structural modification required, with features allowing only designated pets to use the device.  
           [0003]    2. Description of Prior Art  
           [0004]    Pet door devices have been well-know in the field. Early pet door devices were mounted in doors or cut into walls, and consisted of a door panel hinged at the top edge and operated by the pet applying a force against the door panel to allow for through passage. While these early devices permitted pets egress and ingress without the need for owner attention, any animal (or even children or intruders) could pass through the pet door. Subsequent designs sought to incorporate various locking mechanisms with corresponding keys, to allow only certain pets access. Other devices employed power, to allow the pet door to be opened and closed with resort to the pet applying a force against the door panel. In all of these designs, however, the pet door device is a permanent fixture; once installed, it cannot be removed without extensive repair work needed.  
           [0005]    The prior art discloses various pet door devices. One example of a prior art pet door is disclosed in U.S. Pat. No. 5,967,215 (Needham), issued on Oct. 19, 1999. This patent discloses a one- and two-way pet screen door kit for installation in an existing screen door or window screen. This device uses magnetic latches to control access. It also makes use of a ramp for above-ground installations. This device necessarily involves structural modifications to the screen door or window screen for installation purposes. It also does not make use of a pet-specific identification device; any animal carrying a magnetic key will be provided access. The door is also not powered, relying on contact by the animal to push it open.  
           [0006]    A device which improves on the concept disclosed in &#39;215 (Needham) is U.S. Pat. No. 6,141,911 (Reid), issued on Nov. 7, 2000. &#39;911 (Reid) discloses a pet door providing access via a door with a locking/unlocking mechanism activated by a pet-specific key device consisting of a tuned receiver and a signal transmitting key. This allows individual pets to be identified for access, whereby a simple magnetic key permits access to any pet carrying a magnetic key. However, the other deficiencies noted in &#39;215 (Needham) remain with &#39;911 (Reid). Moreover, by utilizing a signal transmitting key, the key device in &#39;911 (Reid) may be overly large and uncomfortable for a pet to wear, and may also present safety concerns.  
           [0007]    U.S. Pat. No. 5,872,516 (Bonge), issued Feb. 16, 1999, discloses a remotely operated pet door which automatically opens under its own power when it receives a signal from an ultrasonic transmitter worn by a pet. This device represents yet another improvement over the concepts disclosed above, in that the door is powered. It does not address the other deficiencies. U.S. Pat. No. 5,177,900 (Solowiej), issued Jan. 12, 1993, discloses an automatic pet door having a vertically moving door activated by a radiation transmitter worn by the pet. This device is similar in concept to &#39;516 (Bonge), except it uses radio signals instead of ultrasonic signals.  
           [0008]    U.S. Pat. No. 6,297,739 (Small), issued on Oct. 2, 2001, discloses a powered automatic pet door using a combination of a pet-specific identification device, a weight sensor, and a motion sensor to control access. The identification device may be implanted subcutaneously in the body of the pet. It also utilizes an interface to a home security system. This device resolves many of the deficiencies present in the prior art. However, it still necessarily involves structural modifications to a door or wall for installation purposes.  
           [0009]    None of the foregoing devices utilize a mounting system adapted for easy installation and deinstallation in ordinary double-hung windows. Nor do the foregoing devices disclose a platform system enabling pets to access the device when it is mounted in out of the way locations or is otherwise inconvenient to the floor or ground. It is an objective of this invention to provide a new and improved automatic pet door device adapted for window mounting. Other objectives of this invention will be readily apparent from the description that follows.  
         SUMMARY  
         [0010]    In one aspect, the invention is directed to a window mounted automatic pet door device having a pet-specific identification component whereby only authorized animals are permitted to access the pet door. The device is intended to solve problems inherent in the prior art by employing a means for installing and using the device in a window, including upper floor windows, without significantly modifying the window unit, thereby increasing the availability of suitable installation locations and appealing to pet owners who do not wish to structurally modify their homes. The device comprises a casing, having a housing component, a pet access platform component, a window mount component, a door positioning component, and an identification component, wherein the casing contains a pet access aperture through which a pet may pass and a laterally sliding door suitably adapted for covering and uncovering the pet access aperture, the pet access platform component is situated adjacent to the pet access aperture providing the pet with a platform next to the door on which to stand when the device is located above ground or floor level, the window mount component secures the device to a double hung window and permits operation of both the device and the window, the door positioning component is electrically powered and activated by the pet and moves the door laterally to cover and uncover the pet access aperture, and the identification component discerns between individual animals and permits access through the door only to designated pets under predetermined conditions.  
           [0011]    The device is intended to be used with small pets, such as cats and small dogs, and may be easily installed and deinstalled in different windows as needed, for example both in a primary residence and seasonally in a vacation home. One aspect of the device employs ramps so that access to the device may be had by pets that cannot jump to the level of a window, such as dogs or older or very young cats, or for use in upper floor windows. The device makes use of a pet-specific identification component, so that different pets in the neighborhood, or even within the same household, can be selectively permitted or denied access to the device.  
           [0012]    Other features and advantages of the invention are described below.  
       
    
    
     DESCRIPTION OF DRAWINGS  
       [0013]    [0013]FIG. 1 is a perspective view of the device showing the door in a partially opened position.  
         [0014]    [0014]FIG. 2 is a top view of the device, with a portion of the top panel cut away at the midline plane. The door is shown in a partially opened position corresponding to the position of the door in FIG. 1.  
         [0015]    [0015]FIG. 3 is a side view of the device as mounted in a double hung window. The final position of the sash fasteners and the bottom fasteners are indicated by dotted lines.  
         [0016]    [0016]FIG. 4 is a rear view of the device with the rear portion of the housing component removed, thereby revealing the door positioning component. The door is shown in a partially opened position corresponding to the position of the door in FIG. 1. The door is also shown in the fully closed position, indicated by the near side edge of the door drawn with dotted lines, and with the first and second pull arms drawn with dotted lines and labeled with a single prime. The position of the second pull arm is also shown when the door is in the fully opened position, indicated by dotted lines and labeled with a double prime.  
     
    
     DESCRIPTION OF THE INVENTION  
       [0017]    [0017]FIG. 1 shows a perspective view of one embodiment of an automatic pet door device  1  adapted for window mounting. The device  1  comprises a pet identification component  14  permitting only designated animals  18  to use the device  1 . The window mount component  10  of the device  1  permits it to be installed in a window  22  without having to structurally alter the window  22 , walls, or doors, as is necessary with other pet door devices. The pet access platform component  8  gives the pet  18  a convenient means for approaching the device  1  when the device  1  is installed above ground or floor level. The device  1  is intended to permit pets  18  to enter or exit a structure, such as a house, garage, or other building, through an existing window  22  in a controlled manner, with a minimum of effort, while minimizing the impact of this activity on the structure and without the need for direct participation by the pet owner.  
         [0018]    The basic components of the device  1  include a casing  2 , which in turn incorporates a housing component  4  and a pet access aperture  16 , a door  20  adapted to cover and uncover the pet access aperture  16 , a pet access platform component  8 , a window mount component  10 , a door positioning component  12  (shown in greater detail in FIG. 4), and an identification component  14 . The casing  2  contains the other components  4 , 8 , 10 , 12 , 14 , which are enclosed within the housing component  4  and/or integrated into and attached to the casing  2 . The window mount component  10  is adapted to secure the device  1  within a double hung window  22 , without necessitating structural modification to the window  22 , and is further adapted to permit operation of the window  22  after mounting the device  1  therein. The window mount component  10  is also adapted to provide weather proofing when the device  1  is in use. The door positioning component  12  comprises electrical and mechanical means for moving the door  20  laterally across the pet access aperture  16 , thereby covering and uncovering the pet access aperture  16 , whereby a pet  18  may pass through the pet access aperture  16  when it is in an uncovered, or open, state, and the pet  18  is prevented from passing through the pet access aperture  16  when it is in the covered, or closed, state. The door positioning component  12  is adapted to position the door  20  without the need for the pet  18  to contact the door  20 . The door positioning component  12  also provides security for the device  1 , maintaining the door  20  in a closed position until the device  1  is properly accessed by a designated pet  18  or by the user. The door positioning component  12  is contained within the housing component  4 , thereby protecting it from the elements and also minimizing the likelihood that the moving elements of the door positioning component  12  will come in contact with the pet  18 , so as to avoid injury. The identification component  14  is adapted to activate the door positioning component  12  when an authorized pet  18  is identified so that the pet  18  may pass through the pet access aperture  16 , initiating a sequence of steps for uncovering the pet access aperture  16  and then covering the pet access aperture  16  with the door  20 . In one embodiment, the identification component  14  is comprised of at least two subcomponents, one of which, the key device  170 , is carried by the pet  18 , the other of which is integrated with the casing  2 . In this embodiment, the identification component  14  is adapted to be activated when a pet  18  carrying the key device  170  comes within a predetermined near proximity to the door  20  of the device  1 ; when such occurs, the identification component  14  resolves whether the pet  18  is permitted access, and if so, activates the door positioning component  12  to position the door  20  in the open position, thereby permitting the pet  18  to pass through the pet access aperture  16 . The identification component  14  may be configured to accept only certain individual pets  18  carrying a key device  170 , or to permit passage of a pet  18  through the pet access aperture  16  in only one direction (e.g., only to let the pet  18  in or only to let the pet  18  out), or to limit the time periods during which a pet  18  may activate the door  20 , or any combination of the foregoing.  
         [0019]    The casing  2  is defined as having an interior portion  38  and an exterior portion  36 , and as having a midline plane  40  oriented substantially vertically which separates the interior portion  38  from the exterior portion  36 . The interior portion  38  of the casing  2  is that portion which, when the device  1  is installed in a window  22 , is located primarily within the interior of the structure containing the window  22 , e.g., “inside the house,” while the exterior portion  36  of the casing  2  is that portion which is located primarily exterior to the structure containing the window  22 , e.g., “outside the house.” The midline plane  40  is oriented substantially coplanar with the glass pane  23  of the window  22 . In one embodiment of the device  1 , the pet access aperture  16  is situated substantially coplanar with the midline plane  40 . A pet  18  utilizing the device  1  to exit a structure approaches the pet access aperture  16  from the interior portion  38  of the casing  2 , then passes through the pet access aperture  16 , and continues past the exterior portion  36  of the casing  2 .  
         [0020]    In addition to the housing component  4 , the casing  2  is comprised of a top panel  42  and a base panel  50 . The top panel  42  is constructed of a rigid material, is substantially planar, is oriented substantially in a horizontal plane, and has an upper surface  46  and a lower surface  48 . The base panel  50  is constructed of a rigid material, is substantially planar, is oriented substantially in a horizontal plane substantially parallel to the top panel  42 , and has an upper surface  52  and a lower surface  54 . The top panel  42  provides the point of contact between the device  1  and the sash  26  of a double hung window  22 . The base panel  50  provides the point of contact between the device  1  and the base of the window unit  22 . The housing component  4  is situated between the top panel  42  and the base panel  50 , with the housing component  4  being fixedly attached to the lower surface  48  of the top panel  42  and fixedly attached to the upper surface  52  of the base panel  50 . In one embodiment, the housing component  4  is comprised of lateral sides constructed of a rigid material and which, together with the top panel  42  and the base panel  50 , define a substantially enclosed space. The lateral sides  6  of the housing component  4  may be constructed of plexiglass, polystyrene, or other such materials providing strength and rigidity along with being light weight. The housing component  4  may be transparent, translucent, tinted, or opaque. In one embodiment the lateral sides  6  of the housing component  4  are oriented substantially vertically. One or more of the lateral sides  6  of the housing component  4  may be removably attached to the rest of the housing component  4 , thereby providing access to the interior of the housing component  4 . The housing component  4  is situated within the casing  2  substantially within the interior portion  38  of the casing  2 . In one embodiment, the top panel  42 , base panel  50 , and housing component  4  may be constructed of high impact plastic using injection molding methods.  
         [0021]    The pet access aperture  16  is situated within the casing  2  adjacent to the housing component  4 . The door  20  controlling access through the device  1  is planar, is constructed of a rigid material, is of a uniform thickness, is substantially rectangular in shape, and is suitably dimensioned to substantially cover the pet access aperture  16 . Other shapes for the door  20  which accomplish the task of completely covering the pet access aperture  16  are also anticipated by this invention. In one embodiment the door  20  is constructed of a transparent, colorless material, thereby giving the pet  18  a clear view through the device  1 . In another embodiment of the device  1 , the pet access aperture  16  is substantially rectangular and defined by an upper track  56  and a lower track  66 , each having a first end  60 , 70  and a second end  62 , 72 , which comprise the top and bottom edges of the pet access aperture  16 , a receiving track  76  having an upper end  78  and a lower end  80 , and the housing component  4 , with the receiving track  76  and the housing component  4  comprising the side edges of the pet access aperture  16 . Each of the tracks  56 , 66 , 76  is constructed of a rigid material. The three tracks  56 , 66 , 76  each comprise a u-shaped channel  64 , 74 , 82  suitably dimensioned to accommodate the thickness of the door  20 . The housing component  4  contains a vertical door aperture  84  adjacent to the pet access aperture  16  and suitably adapted to accommodate the thickness of the door  20 . In this embodiment the upper track  56  is situated along the lower surface  48  of the top panel  42  with the second end  62  of the upper track  56  extending through the vertical door aperture  84  and into the housing component  4 , and with the u-shaped channel  64  of the upper track  56  oriented substantially downward. The lower track  66  is situated along the upper surface  52  of the base panel  50  with the second end  72  of the lower track  66  extending through the vertical door aperture  84  and into the housing component  4 , with the u-shaped channel  74  of the lower track  66  oriented substantially upward and with the lower track  66  oriented substantially parallel to and in alignment with the upper track  56 . The receiving track  76  is situated in connection with the upper track  56  and the lower track  66  such that the upper end  78  of the receiving track  76  is in connection with the first end  60  of the upper track  56  and the lower end  80  of the receiving track  76  is in connection with the first end  70  of the lower track  66 , with the receiving track  76  being oriented substantially perpendicular to both the upper track  56  and the lower track  66  and having a substantially vertical orientation, and with the u-shaped channel  82  of the receiving track  76  oriented substantially towards the vertical door aperture  84 . The upper edge  28  of the door  20  is situated within the u-shaped channel  64  of the upper track  56  and the lower edge  30  of the door  20  is situated within the u-shaped channel  74  of the lower track  66 . When the door  20  is in the closed position the far side edge  32  of the door  20  is situated within the u-shaped channel  82  of the receiving track  76 . When the door  20  is opened the upper and lower edges  28 , 30  of the door  20  slide along the upper and lower tracks  56 , 66 , respectively, and the near side edge  34  of the door  20  passes through the vertical door aperture  84  and the door  20  is drawn into the housing component  4 . The upper and lower tracks  56 , 66  may further comprises a lubricating material  88  set within the u-shaped channels  64 , 74  of the tracks  56 , 66 , thereby facilitating the movement of the door  20  along said tracks  56 , 66 . In one embodiment the three tracks  56 , 66 , 76  may be formed into the casing  2  as a single unit. In yet another embodiment the receiving track  76  may be curved, thereby causing the pet access aperture  16  to have a non-rectangular shape.  
         [0022]    In another embodiment, a portion of the top panel  42  is situated above the pet access aperture  16  and extends to the exterior portion  36  of the casing  2 , thereby forming an exterior roof  86  over the pet access aperture  16 . In yet another embodiment, a portion of the top panel  42  is situated above the pet access aperture  16  and extends to the interior portion  38  of the casing  2 , thereby forming an interior roof  87  over the pet access aperture  16 . In either embodiment the roofs  86 , 87  are suitably adapted to direct the head of the pet  18  downward upon the pet  18  approaching the pet access aperture  16  from the direction of either the exterior portion  36  of the casing  2  or the interior portion  38  of the casing  2 . In doing so it brings the subcomponents of the identification component  14  in close proximity to each other, thereby increasing the effectiveness of the identification sequence. The exterior roof  86  also helps keep rain and snow from coming through the pet access aperture  16  when the door  20  is in the open position. In yet another embodiment, the exterior roof  86  further comprises a roof extension  85  removably attached to the exterior roof  86 , thereby increasing the weather protection offered by the exterior roof  86 . For facilitating shipping and installation of the device  1 , the roof extension  85  may be removed.  
         [0023]    In another embodiment, the casing  2  further comprises an enclosure  93  removably attached to the exterior portion  36  of the casing  2 , such that the enclosure  93  fully encloses the area immediately adjacent to the exterior portion  36  of the casing  2 . This feature is useful, for example, in urban areas where a pet  18  is allowed only restricted egress through the device  1  for safety reasons. The enclosure  93  may be suitably dimensioned to accommodate a litter box  192 , and may be suitably adapted to provide fresh air through apertures  194  and viewing opportunities through windows  196  or clear structural elements, such as walls constructed of a transparent material.  
         [0024]    [0024]FIG. 2 shows details of the pet access platform component  8 . The pet access platform component  8  comprises an exterior platform  90  oriented substantially coplanar with the base panel  50  and situated adjacent to and in connection with the base panel  50  on the exterior portion  36  of the casing  2 . The exterior platform  90  gives the pet  18  a platform on which to stand when the device  1  is located above ground or floor level. A pet  18  can jump onto the exterior platform  90 , and then move towards the pet access aperture  16  to gain entry. In one embodiment the exterior platform  90  is covered by a non-slip material  92 , providing safety to the pet  18 . In another embodiment the exterior platform  90  is removably attached to the base panel  50 , facilitating shipping and installation of the device  1 . If the device  1  is installed at ground or floor level, or there already exists a platform of some sort exterior to the casing  2 , the removable exterior platform  90  need not be utilized. In yet another embodiment, the exterior platform  90  further comprises an exterior ramp  94 . The exterior ramp  94  is removably attached to the exterior platform  90  and extends to the ground or floor, or to some other stable platform, thereby assisting a pet  18  in gaining access to the device  1 . The exterior ramp  94  may come in various sizes and configurations, thereby allowing use of the device  1  in upper story windows  22 .  
         [0025]    In another embodiment, the pet access platform component  8  further comprises an interior platform  96 , oriented substantially coplanar with the base panel  50  and situated adjacent to and in connection with the base panel  50  on the interior portion  38  of the casing  2 . The interior platform  96  gives the pet  18  a platform on which to stand when the device  1  is located above ground or floor level. A pet  18  can jump onto the interior platform  96 , and then move towards the pet access aperture  16  to exit. In one embodiment the interior platform  96  is covered by a non-slip material  92 , providing safety to the pet  18 . In another embodiment the interior platform  96  is removably attached to the base panel  50 , facilitating shipping and installation of the device  1 . If the device  1  is installed at ground or floor level, or there already exists a platform of some sort, such as a piece of furniture, interior to the casing  2 , the removable interior platform  96  need not be utilized. In yet another embodiment, the interior platform  96  further comprises an interior ramp  95 . The interior ramp  95  is removably attached to the interior exterior platform  90  and extends to the floor, or to some other stable platform, thereby assisting a pet  18  in gaining access to the device  1 .  
         [0026]    [0026]FIG. 3 shows details of the window mount component  10 . The window mount component  10  comprises a bottom flange  98  integrated into the lower surface  54  of the base panel  50  and a top flange  108  integrated into the upper surface  46  of the top panel  42 . The bottom flange  98  is adapted to fit against and exterior to an interior window stop  100  located on the lower portion of a window unit  22 , such as a stool cap  27  or a sill  25 . Distributed along the length of the bottom flange  98  are a plurality of bottom flange apertures  104  which pass through the bottom flange  98 . A plurality of bottom fasteners  106  are adapted to pass through the bottom flange apertures  104  and into the window stop  100 . Distributed about the base panel  50  are a plurality of base panel apertures  102  which pass through the base panel  50 . A plurality of bottom fasteners  106  are adapted to pass through the base panel apertures  102  and into the window unit  22 . The bottom fasteners  106  secure the device  1  to the window unit  22  with a minimum of structural modification to the window unit  22 . In one embodiment the bottom fasteners  106  are wood screws.  
         [0027]    The top flange  108  is adapted to fit against and interior to the lower edge of a window sash  26  of a double hung window  22 . Distributed along the length of the top flange  108  are a plurality of top flange apertures  110  which pass through the top flange  108 . A plurality of sash fasteners  112  are adapted to pass through the top flange apertures  110  and into the window sash  26 , thereby securing the window  22  to the device  1 . In one embodiment, the sash fasteners  112  are further adapted to be removably attached to a window sash  26 . In this embodiment the sash fasteners  112  may be cylindrical pins. With the sash fasteners  112  in place, passing through the top flange apertures  110  and into the window sash  26 , the window  22  is secured in the closed position; with the sash fasteners  112  removed, the window  22  may be raised. Additional support devices  113  may be required to maintain the upper sash  26  of the double hung window  22  in the closed position when the device  1  is installed. Moreover, screens, storm windows, and the like, which are situated exterior to the double hung window  22 , may be partially raised and then set down on the top panel  42 , enabling them to function in conjunction with the device  1 .  
         [0028]    The window mount component  10  further comprises a first lateral adaptor panel  114 . The first lateral adaptor panel  114  is substantially rectangular and has a height substantially equal to the height of the casing  2 . It is affixed to the casing  2  on the side of the housing component  4  opposite the pet access aperture  16 , and is of a suitable shape and size to cover an opening in the window  22  between the housing component  4  and the window frame  24 . The first lateral adaptor panel  114  is adapted to permit installation of the device  1  in windows  22  of varying width. In one embodiment the first lateral adaptor panel  114  is adjustable, permitting it to be dynamically extended laterally to cover the space between the housing component  4  and the window frame  24 . In another embodiment the first lateral adaptor panel  114  is delivered as a solid panel to be custom cut by the purchaser to fit the space between the housing component  4  and the window frame  24 .  
         [0029]    In yet another embodiment, the window mount component  10  further comprises a second lateral adaptor panel  116 . The second lateral adaptor panel  116  is substantially rectangular and has a height substantially equal to the height of the casing  2 . It is affixed to the casing  2  on the side of the casing  2  opposite the location of the first lateral adaptor panel  114  and adapted to cover an opening in the window  22  between the casing  2  and a window frame  24  on the side of the casing  2  opposite the first lateral adaptor panel  114 . The use of the second lateral adaptor panel  116  in conjunction with the first lateral adaptor panel  114  gives added flexibility in the size of the window  22  in which the device  1  may be installed. In addition, the use of the two panels  114 , 116  on either side of the casing  2  results in there being smaller spaces on either side of the casing  2  between the casing  2  and the window frame  24 , rather than one large space on only one side of the casing  2 , thereby reducing the risk of a security breach if one or either of the lateral adaptor panels  114 , 116  is compromised. In yet another embodiment one or both of the lateral adaptor panels  114 , 116  may be constructed of a transparent material.  
         [0030]    In yet another embodiment, the window mount component  10  further comprises weather stripping  118  suitably adapted to reduce the incidence of weather passing between the window mount component  10  and the window unit  22 . The weather stripping  118  may consist of rubberized strips, or felt, or any such other suitable material, and should be situated wherever the device  1  is intended to come in contact with the window unit  22 . In one embodiment, the weather stripping  118  is comprised of a rubberized sheet situated along the lower surface  54  of the base panel  50 , a rubberized strip affixed to the upper surface  46  of the top panel  42  along side, adjacent, and exterior to the top flange  108 , and rubberized strips along the edges of the lateral adaptor panels in contact with the window frame  24 . The weather stripping  118  may also consist of a foam insert to be inserted between the upper and lower sashes  26  of a double hung window  22 , thereby reducing the incidence of weather passing between the two window sashes  26  when the device  1  is installed. The presence of the weather stripping  118  serves the additional purpose of acting as a barrier to insects.  
         [0031]    In yet another embodiment, the window mount component  10  further comprises one or more shims  119  suitably adapted to fit between the base panel  50  and the window unit  22 . The use of the shims  119  enables the device  1  to be installed securely in a wide range of window designs. In one embodiment the shims  119  are horseshoe shaped. In another embodiment the shims  119  contain apertures  119 A adapted to be aligned with the base panel apertures  102  and to accommodate the bottom fasteners  106 , thereby securing the shims  119  in place.  
         [0032]    [0032]FIG. 4 shows details of the door positioning component  12 . The door positioning component  12  comprises an electric motor  120 , a power supply  124 , a mechanical positioning component  126 , and a control component  128 . The power supply  124  provides power to the electric motor  120 , enabling it to operate. The control component  128  determines when and in which direction the electric motor  120  operates. The electric motor  120 , when operating, moves the mechanical positioning component  126 , which in turn positions the door  20  to uncover or cover the pet access aperture  16 .  
         [0033]    In one embodiment, the electric motor  120  is situated within the housing component  4  and fixedly attached to the upper surface  52  of the base panel  50 . The electric motor  120  has a shaft  122  and is electronically controlled to operate in one of two opposing directions, such that the shaft  122  may be rotated in either a clockwise or a counterclockwise direction. The mechanical positioning component  126  is also situated within the housing component  4  and is attached to the shaft  122  and to the door  20 . The power supply  124  is in connection with the electric motor  120  and adapted to provide power to the electric motor  120 . In one embodiment the power supply  124  comprises a 110 volt A/C to 12 volt D/C converter with a standard plug at one end, enabling it to be plugged into a standard wall outlet and enabling the device  1  to run on 12 volt D/C.  
         [0034]    [0034]FIG. 4 also shows details of the operation of the mechanical positioning component  126 . The mechanical positioning component  126  comprises a first pull arm  130 , a second pull arm  136 , a pull arm pivot  142 , a first stop block  144 , and a second stop block  148 . The first and second pull arms  130 , 136  are constructed of a rigid material, such as steel, are substantially long and thin in shape, and each has a first end  132 , 138  and a second end  134 , 140 . The first and second pull arms  130 , 136  are pivotally in connection with each other by the pull arm pivot  142  at their respective second ends  134 , 140 . The pull arm pivot  142  may be of any suitable configuration, such as a bolt and washer combination, or a cotter pin, or the like. The first pull arm  130  is pivotally connected at its first end  132  to the door  20  at the near side edge  34  of the door  20 , and the second pull arm  136  is fixedly connected at its first end  138  to the shaft  122  of the electric motor  120 . In this configuration, operation of the electric motor  120  causes the shaft  122  to rotate, thereby rotating the second pull arm  136  about its first end  138  and causing the second end  140  of the second pull arm  136  to travel in an arc, which in turn causes the first pull arm  130  to move and thus results in the door  20  being properly positioned. When the electric motor  120  is activated to open the door  20 , the electric motor  120  causes the second pull arm  136  to rotate about the first end  138  of the second pull arm  136  in an upward and backward direction away from the pet access aperture  16 , pivoting the first pull arm  130  about the first end  132  of the first pull arm  130  in an upward and then downward direction while simultaneously drawing the first pull arm  130  in the direction of the electric motor  120 , thereby drawing the door  20  into the housing component  4  and uncovering the pet access aperture  16 . When the electric motor  120  is activated to close the door  20 , the electric motor  120  causes the second pull arm  136  to rotate about the first end  138  of the second pull arm  136  in an upward and forward direction towards the pet access aperture  16 , pivoting the first pull arm  130  about the first end  132  of the first pull arm  130  in an upward and then downward direction while simultaneously pushing the first pull arm  130  in a direction away from the electric motor  120 , thereby pushing the door  20  out of the housing component  4  and causing the door  20  to cover the pet access aperture  16 .  
         [0035]    The first and second stop blocks  144 , 148  are utilized to control the operation of the electric motor  120 , and the first stop block  144  additionally serves as a security device to prevent the door  20  from being forcibly opened without activation of the electric motor  120 . The first stop block  144  is constructed of a rigid material and has a top side  146 . It is fixedly attached to the upper surface  52  of the base panel  50  and situated directly below the first pull arm  130  when the door  20  is in the closed position. When the door  20  is in a closed position the first end  132  of the first pull arm  130  and the first end  138  of the second pull arm  136  are at substantially the same height above the upper surface  52  of the base panel  50 , and the pull arm pivot  142  is at a slightly lower height than the first ends  132 , 138  of the pull arms, resulting in the first pull arm  130  and the second pull arm  136  forming a shallow v-shape with respect to each other. When so positioned the first pull arm  130  rest on the top side  146  of the first stop block  144 . The second stop block  148 , also constructed of a rigid material and having a top side  150 , is fixedly attached to the upper surface  52  of the base panel  50  and situated on the opposite side of the electric motor  120  from the door  20  and directly below the first pull arm  130  when the door  20  is in the fully opened position. When the door  20  is in a fully opened position the second pull arm  136  has been rotated slightly more than  180  degrees from its shallow v-shape orientation, resulting in the second pull arm  136  being oriented substantially horizontally, and the first pull arm  130  being aligned substantially in parallel with the second pull arm  136 . In this position, the first pull arm  130  comes into contact with the top side  150  of the second stop block  148 , thereby preventing further rotation of the second pull arm  136  and any further movement of the door  20 . Attached to both stop blocks  144 , 148  are limit switches  154 , 156 . When the pull arms contact the stop blocks the limit switches  154 , 156  are engaged, which then cause the operation of the electric motor  120  to stop.  
         [0036]    Because of the shallow v-shape of the pull arms  130 , 136  relative to each other when the door  20  is in the closed position, any lateral force applied to the door  20  in an attempt to open it without use of the electric motor  120  would tend to cause the pull arms  130 , 136  to pivot downward; however, the first stop block  144  prevents the pull arms  130 , 136  from moving in such a direction, thereby effectively locking the door  20  in the closed position. The control component  128  of the device  1  comprises an activation component  152 , a first limit switch  154  fixedly attached to the first stop block  144 , a second limit switch  156  fixedly attached to the second stop block  148 , a timer  158 , and a motor controller  160 . The activation component  152  is in connection with the motor controller  160 ; upon the occurrence of an appropriate activation event, the activation component  152  causes the motor controller  160 , which is in connection with the electric motor  120 , to activate the operation of the electric motor  120  in a first direction such that the mechanical positioning component  126  draws the door  20  into the housing component  4 , thereby uncovering the pet access aperture  16 . The second limit switch  156  is in connection with the motor controller  160  and with the timer  158 ; when the first pull arm  130  contacts the second stop block  148  and causes the second limit switch  156  to become engaged, indicating that the door  20  has reached the fully opened position, the second limit switch  156  causes the motor controller  160  to deactivate the operation of the electric motor  120  and causes the activation of the timer  158 . The timer  158 , which is in connection with the motor controller  160 , upon the expiration of a predetermined period of time after its activation, causes the motor controller  160  to activate the operation of the electric motor  120  in a second direction opposite the first direction such that the mechanical positioning component  126  pushes the door  20  out of the housing component  4 , thereby covering the pet access aperture  16 . The first limit switch  154  is in connection with the motor controller  160 ; when the first pull arm  130  contacts the first stop block  144  and causes the first limit switch  154  to become engaged, indicating that the door  20  has reached the fully closed position, the first limit switch  154  causes the motor controller  160  to deactivate the operation of the electric motor  120 . In one embodiment, the time-out period for the timer  158  is five seconds. In another embodiment, the time-out period may be adjusted as desired. As a safety feature, the electric motor  120  is suitably adapted to provide the minimal force necessary to position the door  20 . Thus, if a pet  18  remains within the pet access aperture  16  when the door  20  is in the process of closing, the contact of the door  20  with the pet  18  will not harm the pet  18 . In another embodiment, a safety microswitch  166  is in connection with the motor controller  160  and mounted on the first end  132  of the first pull arm  130 , and the first pull arm  130  is attached to the door  20  within a channel  167 . Upon contact of the door  20  with a pet  18 , continued force by the electric motor  120  causes the first pull arm  130  to slide within the channel  167  and engage the safety microswitch  166 , which then activates the motor controller  160  to reverse the electric motor  120 . Other embodiments of the control component  128  may be evident to those skilled in the art. This specification contemplates and incorporates all such embodiments for use with the device  1 .  
         [0037]    The activation component  152  of the control component  128  comprises the identification component  14 , in connection with the motor controller  160 . The occurrence of an appropriate activation event is identified by the identification component  14  which then signals the motor controller  160  to begin the sequence of opening and closing the door  20 . In one embodiment, the identification component  14  comprises a key device  170 , also known as a transponder, adapted to be carried by a pet  18  and suitably adapted to transmit a radio signal  162  in an identifiable manner, and a radio frequency identification component  172 , also known as an interrogator or reader, situated within the housing component  4  and suitably adapted to transmit and receive radio signals  162  a short distance exterior to the housing component  4  and in near proximity to the door  20 . The key device  170  is energized by the radio signals  162  transmitted by the radio frequency identification component  172 ; it therefore does not need its own independent power supply. The combination of a key device  170  and a radio frequency identification component  172  is well known in the industry. In one embodiment, the radio frequency identification component  172  is adapted to generate a weak radio signal  162  with an effective range of a few inches of the door  20 . An antenna  173  monitors for the presence of radio signals  162  generated by the key device  170 . When the key device  170  is brought within the field of the radio signals  162 , it is energized by the radio signals  162  transmitted by the radio frequency identification component  172  and in turn transmits its own signal  162 , which is received by the radio frequency identification component  172 . The radio frequency identification component  172  compares the radio signal  162  from the key device  170  against a predetermined selection; a match indicates that the key device  170  corresponds to an authorized pet  18  and the door opening sequence is initiated. Multiple key devices  170  may be used with the device  1 . A new key device  170  is initialized by placing it within the field of radio signals  162  transmitted by the radio frequency identification component  172  and causing the radio frequency identification component  172  to register the key device  170  for future identification. In one embodiment the key device  170  is a collar tag to be worn by the pet  18 . In another embodiment the key device  170  may be a subcutaneous implant. Thus, other pets  18  wearing similar key devices  170  can be screened, and access to the device  1  can be accurately controlled to the individual pet  18 . This is an improvement over other devices disclosed in the prior art using non-specific identification keys, such as magnets, which would permit access to any pet  18  wearing a magnet key. In high density populations the number of pets  18  carrying identification keys is likely to be significant, thereby the use of an identification component  14  as disclosed herein increases the effectiveness of access control over the prior art devices which use non-specific keys for controlling access. Other embodiments of the radio frequency identification component  172  may be utilized in the device  1 , provided the function of individual pet identification is met.  
         [0038]    In another embodiment, the activation component  152  further comprises a pressure plate  164  and a microswitch  166 A. The pressure plate  164  is spring-mounted onto the interior platform  96  proximate to the door  20 , such that the application of a downward force on the pressure plate  164  causes the pressure plate  164  to move downward towards the interior platform  96  and the removal of the downward force allows the pressure plate  164  to move upward away from the interior platform  96 . The microswitch  166 A is situated on the interior platform  96  below the pressure plate  164 , is in connection with the motor controller  160 , and is suitably adapted to send a signal to the motor controller  160  when activated. The application of a sufficient downward force to the pressure plate  164  causes the pressure plate  164  to move downwards until it contacts the microswitch  166 A, which then begins the sequence of opening and closing the door  20 . Such a downward force is calibrated to approximate the weight of a small pet  18  standing on the pressure plate  164 .  
         [0039]    In yet another embodiment, the activation component  152  further comprises a bypass switch  168 . The bypass switch  168  is in connection with the motor controller  160  and is suitably adapted to send a signal to the motor controller  160  when the bypass switch  168  is manually activated. In one embodiment the bypass switch  168  is mounted on the housing component  4 .  
         [0040]    In yet another embodiment, the activation component  152  further comprises a magnetic key  182 , adapted to be carried by a pet  18 , and a relay  184  suitably adapted to be activated by a magnetic field, situated within the housing component  4  and suitably adapted to activate the motor controller  160 .  
         [0041]    In one embodiment of the device  1 , the control component  128  further comprises a data entry pad  174  and a first interface component  176 . The first interface component  176  is in connection with the data entry pad  174  and is suitably adapted to communicate data between the data entry pad  174  and the control component  128  to perform control functionality. In this embodiment, the data entry pad  174  may be used to set the time-out period of the timer  158 , to select which of multiple key devices  170  will be permitted access, to establish timing and directional restrictions on an individual pet&#39;s  18  access to the device  1 , and to control other aspects of the device  1 . The data entry pad  174  may be configured any number of ways, including having a numeric keypad, or up/down scroll buttons, or other suitable means for accomplishing the desired functionality.  
         [0042]    In another embodiment of the device  1 , the control component  128  further comprises a second interface component  178  suitably adapted to communicate with a computer  180  for data gathering, processing, and control functionality. Thus, a user can not only modify control aspects of the device  1 , but can also gather and analyze data concerning the use patterns of the device  1  by authorized pets  18 . Utilizing the functionality of the internet, the second interface component  178  may allow control and monitoring of the device  1  from remote locations, such as when a pet owner is on vacation. The second interface component  178  is adapted for use with a personal computer  180  utilizing software appropriate for the functionality desired.  
         [0043]    As described, the device  1  is an improved design for an automatic pet access door over the prior art. It allows installation in a window  22 , thereby avoiding the major structural modification requirements of prior art designs, as well as allowing easy portability, from room to room as needed or even from house to vacation home, for example, if the pet  18  resides in different seasonal locations. The device  1  incorporates a pet-specific identification component  14  to better restrict access to only authorized pets  18 . The pet access platform component  8  and the available ramp system allows installation of the device  1  in otherwise inconvenient locations, increasing its utility to the pet owner.  
         [0044]    Modifications and variations can be made to the disclosed embodiments of the device  1  without departing from the subject or spirit of the device  1  as defined in the following claims.

Summary:
A window mounted automatic pet door device having a pet-specific identification component whereby only authorized animals are permitted to access the pet door. The device is intended to solve problems inherent in the prior art by providing for installation and use of the device in a window, including upper floor windows, without significantly modifying the window unit, thereby increasing the availability of suitable installation locations and appealing to pet owners who do not wish to structurally modify their homes. It also provides a pet access platform component to give a pet a convenient structure for approaching the device when it is installed above ground or floor level.