Abstract:
A doorway having a recessed magnetic lock is disclosed. The doorway that comprises a jamb that defines an interior jamb space. The jamb includes a stop surface that defines a jamb opening between the interior jamb space and an exterior space. The doorway further comprises an electromagnet housed within the interior jamb space that is operable to provide an attractive magnetic force. The doorway further comprises a door pivotally connected to the jamb to open and close the doorway. The door defines an interior door space and includes a front surface. The front surface defines a door opening between the interior door space and the exterior space. The doorway further comprise a magnetically attractive armature housed within the interior door space. The armature is abuttingly engagable with the electromagnet when the doorway is closed.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This claims the benefit of the filing date of U.S. Provisional Patent Application No. 61/160,531 filed Mar. 16, 2009, the entire disclosure of which is hereby incorporated for all purposes. 
     
    
     STATEMENT CONCERNING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       FIELD OF THE INVENTION 
       [0003]    This invention relates to magnetic locks for doorways, and more particularly to abutting-type magnetic locks. 
       BACKGROUND OF THE INVENTION 
       [0004]    Magnetic locks are widely used in different fields to secure various types of entryways, such as gates, doors, and the like. These locks can resist forces comparable to those of conventional mechanical locks and offer a number of other advantages over mechanical locks; for example, magnetic locks can be more reliable than mechanical locks because they include few moving parts, if any. That is, magnetic locks do not use parts similar to those of conventional locks, such as pins, springs, and cams. Instead, magnetic lock designs typically include a fixed electromagnet connected to the door frame or jamb that provides an attractive magnetic force when electrically energized by a power source. The electromagnet attracts and holds a magnetically attractive armature fixed to the door thereto, thereby securing the door to the jamb. 
         [0005]    Magnetic locks, while being effective substitutes for mechanical locks, include several disadvantages. For example, magnetic locks are typically manufactured separately from doorways on which they are used, and magnetic locks are not typically considered when designing a doorway. As a result, most magnetic locks are installed such that the electromagnet extends from the jamb inwardly to the entryway. These designs are sometimes struck by objects passing through the doorway, and adjustments are then needed to ensure proper lock function. In addition, designs with exposed electromagnets typically include exposed wiring that can catch on objects or permit tampering to disable the magnetic lock. Further still, the electromagnet, the armature, or both components form horizontal ledges on which dust can collect and cause cleaning difficulties; this is especially problematic if the doorway is used in a “clean” environment, such as those of some laboratories. 
         [0006]    An end user needs to perform a substantial amount of labor or enlist a technician to install a doorway with a conventional magnetic lock. First, the jamb, door, and hinge must be mounted accurately to ensure proper motion of the door. Next, several holes must be carefully marked and drilled to attach the electromagnet and the armature on the doorway. After installation, the end user or technician may have to adjust the magnetic lock components to ensure proper lock function. 
         [0007]    Considering the limitations of previous magnetic lock designs, a need exists for a doorway having a recessed magnetic lock in which the amount of labor required by the end user is reduced. A need also exists for such a doorway to be less susceptible to tampering and contact with objects passing through the doorway. Further still, a need exists for such a doorway to provide a cleanable ledge-free door assembly. 
       SUMMARY OF THE INVENTION 
       [0008]    In one aspect, the present invention provides a doorway that comprises a jamb that defines an interior jamb space. The jamb includes a stop surface that defines a jamb opening between the interior jamb space and an exterior space. The doorway further comprises an electromagnet housed within the interior jamb space that is operable to provide an attractive magnetic force. The doorway further comprises a door pivotally connected to the jamb to open and close the doorway. The door defines an interior door space and includes a front surface. The front surface defines a door opening between the interior door space and the exterior space. The doorway further comprise a magnetically attractive armature housed within the interior door space. The armature is abuttingly engagable with the electromagnet when the doorway is closed. 
         [0009]    In another aspect of the invention, the doorway comprises a jamb that includes a stop surface and an electromagnet housed within the jamb that is operable to provide an attractive magnetic force. The electromagnet includes an exposed face being one of recessed in the jamb and flush with the stop surface. The doorway further comprises a door pivotally connected to the jamb to open and close the doorway, and the door includes a front surface that is engagable with the stop surface to close the doorway. The doorway further comprises a magnetically attractive armature housed within the door. The armature includes an exposed face that is abuttingly engagable with the electromagnet when the doorway is closed. The exposed face is one of recessed in the door and flush with the front surface. 
         [0010]    In yet another aspect of the invention, the doorway comprises a jamb that defines an interior jamb space and includes a stop surface. The stop surface defines a jamb opening between the interior jamb space and an exterior space. The doorway further comprises a door that is pivotally connected to the jamb to open and close the doorway. The door defines an interior door space and includes a front surface that is engagable with the stop surface to close the doorway. The stop surface defines a door opening between the interior door space and the exterior space. The doorway further comprises a magnetic lock that includes an electromagnet disposed within the interior jamb space that is operable to provide an attractive magnetic force. The electromagnet includes an exposed face nearest the exterior space that faces a direction in which individuals pass through the doorway. The exposed face is one of recessed in the interior jamb space and flush with the stop surface. The magnetic lock further includes a magnetically attractive armature disposed within the interior door space configured to engage the electromagnet. The armature further includes an exposed face nearest the exterior space that faces opposite the direction faced by the electromagnet when the doorway is closed. The exposed face of the armature is one of recessed in the interior door space and flush with the front surface. 
         [0011]    The foregoing and other objects and advantages of the invention will appear in the detailed description which follows. In the description, reference is made to the accompanying drawings which illustrate a preferred embodiment of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and: 
           [0013]      FIG. 1  is a perspective view of a doorway of the present invention with the door open; 
           [0014]      FIG. 2  is a front view of the doorway of  FIG. 1  with the door closed; 
           [0015]      FIG. 3  is a side sectional view taken along line  3 - 3  of  FIG. 2 ; 
           [0016]      FIG. 4  is a top sectional view taken along line  4 - 4  of  FIG. 2 ; 
           [0017]      FIG. 5  is a partial front view of a jamb of the doorway of  FIG. 1 ; 
           [0018]      FIG. 6  is a partial front view of the door of  FIG. 1 ; 
           [0019]      FIG. 7  is a perspective view of a magnetic lock of the doorway of  FIG. 1  separate from the other components; 
           [0020]      FIG. 8  is a partial front view of an embodiment of the doorway including a door closer; and 
           [0021]      FIG. 9  is a partial rear view of the embodiment of the doorway of  FIG. 8  with the door closed. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    The particulars shown herein are by way of example and only for purposes of illustrative discussion of the embodiments of the invention. The particulars shown herein are presented to provide what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for the fundamental understanding of the invention. The description taken with the drawings and photographs should make apparent to those skilled in the art how the several forms of the present invention may be embodied in practice. 
         [0023]    Referring to  FIGS. 1-7 , the present invention provides a doorway  10  that includes a magnetic lock  12  that has an electromagnet  14  mounted within the door jamb  16 . The electromagnet  14  is electrically energized by a power source (not shown) to provide a magnetic force that attracts a striker plate or armature  18  mounted within the door  20 . When the door  20  is closed and the electromagnet  14  is energized, the electromagnet  14  holds the armature  18  thereto, thereby securing the doorway  10 . These components and their interactions are described in further detail in the following paragraphs, beginning with the magnetic lock  12  and then proceeding to the jamb  16  and the door  20 . 
         [0024]    Still referring to  FIGS. 1-7 , the electromagnet  14  and the armature  18  of the magnetic lock  12  include exposed faces  22  and  24 , respectively, that abuttingly engage one another when the door  20  is closed. In this context, the term “abuttingly engage” should be understood in contrast to shearly engaging or shear-type magnetic locks that face vertically; that is, the exposed face  22  of the electromagnet  14  faces a direction in which individuals may pass through the doorway  10 , and the exposed face  24  of the armature  18  faces the opposite direction when the door  20  is closed. Unlike shear-type magnetic locks, the magnetic lock  12  does not include grooves in which dust can collect. The exposed face  22  of the electromagnet  14  may include upper electromagnet core surfaces  25  defined by E-shaped electromagnet core laminations. The electromagnet  14  and the armature  18  also include holes through which fasteners  26  and  28  pass to secure the components to the jamb  16  and the door  20 , respectively. 
         [0025]    The armature  18  is preferably about 6½″ long, 1⅝″ tall, and ½″ wide. The electromagnet  14  is preferably about 8″ long, 1¾″ tall, 1½″ wide and may require about 3.6 W of power. Thus, the electromagnet  14  draws about 300 mA when powered by a 12VDC source and 150 mA when powered by a 24VDC source. The magnetic lock  12  as described above preferably provides a holding force of about 600 lbs. An appropriate magnetic lock design for these dimensions and specifications is model M32 manufactured by Securitron Magnalock Corporation of Sparks, Nev., although other designs may also be used. 
         [0026]    Referring now to  FIGS. 1-5 , the door jamb  16  includes two vertical spans  30 , one of which includes a hinge  31  that connects to the door  20 , and an upper horizontal span  32  connecting the vertical spans  30 . Each of the spans  30  and  32  are preferably hollow components that have welded sheet metal surfaces, such as 16-gauge 304-#4 stainless steel surfaces. Other materials may also be used to form the surfaces of the spans  30  and  32 , such as fiberglass and the like. The overall size of the jamb  16  may vary depending on the application in which the doorway  10  is used. In an exemplary embodiment, the vertical spans  30  are about 2⅝″ long and 6″ wide, and the horizontal span  32  is about 4⅝″ high and 6″ wide. 
         [0027]    The spans  30  and  32  define a front section  36  that surrounds the door  20  when closed. The spans  30  and  32  also define a recessed inner section  38  and a stop surface  40  against which the door  20  closes. The stop surface  40  may be recessed from the surface of the front section  36  by about 1 15/16″. It is also contemplated that the interface between the door  20  and the stop surface  40  may include seals, flexible stoppers, or the like; in this context, a statement of the door  20  engaging the stop surface  40  should be understood to be open to these alternatives. 
         [0028]    As described briefly above, the spans  30  and  32  are preferably hollow components; in addition, the upper span  32  defines an interior jamb space  42  ( FIGS. 3 and 4 ) that accommodates the electromagnet  14 . A lower surface  44  of the upper span  32  supports the electromagnet  14  and two brackets  46  within the space  42  secure the electromagnet  14  to the span  32 . The brackets  46  may be welded to the upper span  32  and connected to the fasteners  26 , in an exemplary embodiment, by ¼-20 threaded fastener mounts. The electromagnet  14  and the brackets  46  are disposed in the space  42  proximate an opening  48  ( FIGS. 3 and 5 ) defined by the stop surface  40 ; the exposed face  22  of the electromagnet  14  is preferably disposed in the opening  48  and flushly aligned with the stop surface  40 . The upper span  32  may house one or more shims (not shown) between the electromagnet  14  and the brackets  46  to ensure the exposed face  22  is properly oriented relative to the stop surface  40 . Alternatively, the exposed face  22  may be slightly recessed in the interior jamb space  42 . In any case, the exposed face  22  is the face of the electromagnet  14  nearest to the exterior of the doorway  10 . 
         [0029]    From the previous paragraphs it should be apparent that the upper span  32  and the brackets  46  advantageously protect the electromagnet  14  from being struck and moved from an appropriate position. This construction also advantageously provides a jamb  16  that is easy to clean because the electromagnet  14  does not form any horizontal ledges. 
         [0030]    Referring now to  FIGS. 1-4  and  6 , the door  20  includes a handle  50 , a front surface  52  that engages the stop surface  40  of the jamb  16 , and, in some embodiments, a rabbet  53  that supports a window  54 . The door  20  is also preferably a hollow component that has sheet metal surfaces, such as 16-gauge 304-#4 stainless steel surfaces. Other materials may also be used to form the surfaces of the door  20 , such as fiberglass and the like. The overall size of the door  20  may vary depending on the size of the jamb  16 . In an exemplary embodiment, the door  20  is about 1¾″ wide. 
         [0031]    The door  20  defines an interior door space  56  ( FIG. 3 ) that accommodates the armature  18 . A bracket  58  supports the armature  18  within the space  56 , and the bracket  58  may be welded and/or connected to the door  20  via the fastener  28 . In an exemplary embodiment, the bracket  58  provides a pocket for the armature  18  that is ¾″ deep. The armature  18  and the bracket  58  are disposed in the space  56  proximate an opening  60  ( FIGS. 3 and 6 ) defined by the front surface  52 , and the exposed face  24  of the armature  18  is preferably disposed in the opening  60  and flushly aligned with the front surface  52 . Alternatively, the exposed face  24  may be slightly recessed in the interior door space  56 . In either case, the exposed face  24  is the face of the armature  18  nearest the exterior of the doorway  10 . This construction advantageously provides a door  20  that is easy to clean because the armature  18  does not form any horizontal ledges. 
         [0032]    Referring now to  FIGS. 8 and 9 , in some embodiments the doorway  10  includes several additional components. For example, the doorway  10  may include a position switch  62  that monitors whether the door  20  is open or closed. The position switch  62  may be connected to a control circuit (not shown) within or outside the jamb  16  so that security personnel can monitor the status of the door  20 . The position switch  62  may be any appropriate design known to those skilled in the art. As another example, the doorway  10  may include light emitting diodes  64  that indicate if it is permissible to pass through the doorway  10 . The light emitting diodes  64  may also connect to the control circuit. The light emitting diodes  64  may be any appropriate designs known to those skilled in the art. The doorway  10  may also include other components known to those skilled in the art, such as keypads and/or card readers (not shown) that control operation of the magnetic lock  12 , gang electrical boxes (not shown), and the like. In any case, the wiring that connects these components to the magnetic lock  12  and/or the control circuit is advantageously concealed in the jamb  16  to prevent tampering and contact with objects passing through the doorway  10 . 
         [0033]    As another example, in some embodiments the edges and bottom of the door  20  include seals (not shown) and a sweep (not shown), respectively, that permit the doorway  10  to be used in certain applications, such as life science laboratories. Appropriate seal and sweep designs will be recognized by those skilled in the art. 
         [0034]    As yet another example, the doorway  10  may include a concealed closer  66  that closes the door  20  after being opened. The closer  66  includes a housing  68  disposed within the interior jamb space  42  that drives an arm assembly  70  to close the door  20 ; the housing  68  and the arm assembly  70  are preferably configured to permit a maximum door swing of 90 to 105 degrees. The closer  66  is also preferably disposed near the vertical span  30  connected to the hinge  31  and the magnetic lock  12  is near the other vertical span  30 . Appropriate closer designs are those from the 5010 series manufactured by LCN Closers of Princeton, Ill., although other designs may also be used. 
         [0035]    From the above disclosure it should be apparent that the doorway of the present invention includes a jamb and a door that are designed for use with a magnetic lock. In addition, the magnetic lock is preferably assembled to the jamb and the door before installation of the doorway. As a result, the amount of labor needed to install the doorway is reduced. For example, the jamb, door, and hinge do not need to be mounted with high accuracy because the magnetic lock components are pre-mounted. As another example, accurate holes do not need to be marked and drilled to attach the lock to the doorway. It should also be apparent that the doorway of the present invention advantageously provides a ledge-free structure for easy cleaning and an inconspicuous design that prevents tampering and contact with objects passing through the doorway. 
         [0036]    A preferred embodiment of the invention has been described in considerable detail. Many modifications and variations to the preferred embodiment described will be apparent to a person of ordinary skill in the art. Therefore, the invention should not be limited to the embodiment described, but should be defined by the claims that follow.