Patent Publication Number: US-2013228296-A1

Title: Window security screen and latch assembly

Description:
FIELD 
     This application is directed to security screens and more particularly to a latch assembly for a window security screen. 
     BACKGROUND 
     Window security screens look similar to insect screens. Functionally, however, window security screens are much sturdier and stronger than insect screens. Window security screens are typically made of a heavy gauge wire cloth or a perforated metal panel mounted inside a screen frame and can protect windows from external penetration and/or against breakage by rocks or other items that may be accidentally or intentionally directed toward the window. Window security screens are increasingly installed over windows in many institutional and commercial settings because these screens provide enhanced protection from crime and vandalism, while having a less noticeable impact on the aesthetic appearance and architecture compared to traditional alternatives such as bars, metal shutters, and the like. 
     In addition to protection from external forces that might penetrate a window, including those resulting from crime and vandalism attempts, window security screens also provide much greater safety over insect screens from internal penetration and are useful in preventing tragic events such as small children that occasionally fall through an open window covered only by a closed insect screen. Despite these benefits, window security screens are not widely used in single-family homes or other conventional residential settings outside of public housing. Security screens may be perceived as less user-friendly than insect screens and may also be perceived to have a negative aesthetic effect that is more easily noticed in a residential environment than in commercial or institutional environments. 
     Various solutions have been presented to address the aesthetic concerns, including providing security screens designed to fit within the screen track typically provided in a window for a traditional insect screen. However, window security screens heretofore have still failed to be sufficiently user-friendly to encourage their use, even where aesthetic considerations can be addressed. One of the main challenges to this effort is to provide a user with an ability to readily open and/or remove the screen both for casual use, as well as for escape in an emergency, while still ensuring that the security screen cannot be readily compromised via the exterior side or opened by a child on the interior side. 
     What is needed is a latch assembly for use in combination with a window security screen that permits the security screen to be installed within the screen window track of a window, while allowing it to be opened quickly and easily from the interior by an adult while meeting current child safety considerations. 
     SUMMARY 
     In one embodiment, a latch assembly for attaching a screen to a window frame comprises a latch housing, a locking pin extending through the latch housing sized to extend through a side of the screen and into the window frame, and a latch release disposed within the latch housing. The latch release is biased to prevent the locking pin from moving in a direction away from the side of the screen in the absence of an external force applied to the latch release. 
     In another embodiment, a window security screen comprises the latch assembly, a screen frame and an infill attached to the screen frame, the latch assembly attached to the screen frame. 
     An advantage of certain embodiments is that the latch assembly can be employed with a window security screen mounted in the window screen track of a window to permit the security screen to easily be opened and/or removed via the interior but not the exterior. 
     Another advantage of certain embodiments is that the latch assembly permits the security screen to be removed by an adult without the use of tools. 
     Yet another advantage of certain embodiments is that the latch assembly cannot be readily opened from the interior by a child. 
     Other features and advantages of the present invention will be apparent from the following more detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a window security screen mounted within a window in accordance with an exemplary embodiment. 
         FIG. 1   a  illustrates a partial enlarged view of the window security screen of  FIG. 1 . 
         FIG. 2  illustrates a perspective view of a latch assembly in accordance with an exemplary embodiment. 
         FIGS. 3-5  provide a cross-sectional plan view of the latch assembly of  FIG. 2  that illustrates latch operation. 
         FIG. 6  illustrates a plan view of a latch assembly in accordance with another exemplary embodiment. 
       Where like parts appear in more than one figure, it has been attempted to use like reference numerals to identify such parts. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       FIG. 1  illustrates an exterior view of a window security screen  10  mounted within a window frame  5  of a window of a home. More specifically, the window security screen  10  is mounted within a window screen track formed in the window frame  5 , which is a common feature formed in most windows to receive and retain an insect screen. The window security screen  10  is locked in place within the frame  5  by a latch assembly  100  attached on an interior side of the screen  10 . It will further be appreciated that while exemplary embodiments are described herein in the context of a latch assembly  100  for a window security screen, the latch assembly  100  might also be useful with traditional insect screens or in other applications. 
     The screen  10  has a frame  15  and infill  20 . In embodiments in which the screen  10  is a window security screen, the frame  15  is typically constructed of an extruded galvanized steel or aluminum, although any material that provides sufficient strength may be used. The infill  20  for the window security screen  10  may be a perforated metal panel or a wire mesh, for example. Typically, for embodiments in which the infill  20  is a perforated panel, the panel is generally selected as a  12  gauge,  16  gauge, or  18  gauge steel panel depending upon the environment in which the screen  10  will be used and the level of protection desired. For embodiments in which the infill  20  is a wire mesh, the mesh is typically selected to be 0.028 in. wire mesh, 0.023 in. wire mesh, or 0.047 in. wire mesh and may be constructed of stainless steel or other suitable material. It will be appreciated, however, that the materials of construction of the frame  15  and the types and sizes of infill  20  are exemplary only, and that any materials used in the security screen industry may be employed with security screens  10  in accordance with exemplary embodiments. 
     The screen frame  15  may be constructed so that it is generally flush with at least a portion of the window frame  5  when the screen  10  is installed. This may aid in preventing crowbars, screwdrivers, or other burglar&#39;s tools from gaining a foothold for prying the screen  10  from the window frame  5  from the exterior. The latch assembly  100  operates independent of the depth of screen track, which can vary by manufacturer and typically ranges from 0.25 inches to 0.5 inches. 
     The latch assembly  100  is positioned on the interior side of the screen  10 . It secures the screen  10  to the window frame  5  and provides a user with an ability to remove the screen  10  from the window frame  5  without the aid of additional tools and without compromising the security the screen  10  provides from vandals or burglars. Because of the high strength infill  20  used with the security screen  10  and its corresponding resistance to knives and cutting tools, the latch assembly  100  cannot be readily accessed from the outside. 
     The window security screen  10  may include multiple latch assemblies  100  positioned at various locations about the screen  10 , for example, near each of the four corners. Alternatively, a single latch may be sufficient to secure the screen  10  within the screen track of the window frame  5 .  FIG. 1  a illustrates an enlarged view of the latch assembly  100  attached to the frame  15  of the window security screen  10 , viewed from the interior of the home. The infill  20  is omitted from  FIG. 1   a  for purposes of illustration.  FIG. 1   a  also illustrates an exemplary cross-sectional profile of the extruded screen frame  15 , which is one way in which enhanced strength can be achieved in the screen frame  15  for its use in security screen  10 . 
     The latch assembly  100  includes a latch housing  110 , a locking pin  120  and a release  140  that together provide for a two-step latch that results in the latch assembly  100  being child resistant and which can be actuated without tools. Thus, exemplary embodiments are compliant with ASTM Designation F2090-10 entitled “Standard Specification for Window Fall Prevention Devices with Emergency Escape (Egress) Release Mechanisms,” which is hereby incorporated by reference. 
     The latch assembly  100  may be secured to the screen frame  15  by screws or other fasteners. The locking pin  120  extends from the latch housing  110  through the screen frame  15  into the window frame (not shown in  FIG. 1   a ), thereby securing the screen  10  to the window frame. When released, the locking pin  120  can be withdrawn from the window frame, permitting the entire screen to be removed from the window frame for repair, maintenance or other reason, as well as to provide egress in case of emergency. 
     Alternatively, in some embodiments, the screen frame  15  may be attached to the window frame by screws or other fasteners, for example, while the infill  20  is hingedly attached to one side of the screen frame  15 . In such cases, the latch assembly  100  may be used to lock the infill  20  to the screen frame  15 , such that when the latch assembly  100  is unlocked, the infill  20  can be swung open via its hinges to provide egress in case of emergency, while the screen  10  itself remains secured to the window frame  5 . 
     Turning to  FIG. 2 , the latch assembly  100  is shown with the position of the screen frame  15  and window frame  5  shown schematically in broken line for context in the illustration. The locking pin  120  may include a handle  130 , illustrated here as a pull ring, to aid a user in withdrawing the locking pin  120  from the window frame  5  after the release  140  has been activated. The pull ring is exemplary only and the handle  130  may be a tab, a tee, an eye hook, or any other feature that aids in grasping the locking pin  120 . 
     The release  140  is partially disposed within the latch housing  110  and exerts a bias force to resist axial movement by the locking pin  120  that keeps the latch assembly  100  in a locked position. As a result, the locking pin  120  cannot be retracted from the window frame  5  to remove or open the screen without a first action to counter the bias force of the release  140 , followed by a subsequent, separate action of pulling the pin  120  away from and out of the window frame  5 . 
     The latch housing  110  may also include a tab  112  that extends away from the frame  15 . The tab  112  provides a convenient surface by which the release  140  can easily be activated by squeezing the release  140  and tab  112  with, for example, the thumb and forefinger. 
     The latch assembly  100  may also include a travel stop  160  that extends into the latch housing  110  to establish a point of maximum travel of the locking pin  120  away from the frame  15  so that the locking pin  120  is not pulled completely out of the latch assembly  100  and inadvertently misplaced. In the illustrated embodiment, the travel stop  160  may be a screw or other fastener which provides the option of adjusting the depth of the travel stop or the travel stop  160  can be removed entirely in situations where it is desired to entirely remove the locking pin  120  from the latch assembly  100 , such as for cleaning. 
     In  FIGS. 3-5 , a cross-sectional plan view of the latch assembly  100  from  FIG. 2  is shown that sequentially illustrates a transition from the locked to the unlocked positions, in which the screen frame  15  and window frame  5  are again shown in broken line for purposes of illustration. 
     Beginning with  FIG. 3 , the latch assembly  100  is shown in the locked position, with the locking pin  120  resident in a locking pin channel  128  and fully extended through the screen frame  15  and into the window frame  5  to secure the screen to the window frame  5  within the screen track. The release  140  is biased to keep the locking pin  120  in that locked position. As illustrated, the bias force may be achieved by a spring  150  internal the latch housing  110  that forces a release catch portion  142  of the release  140  toward the locking pin  120 . 
     To enhance the locking force exerted by the release  140  on the locking pin  120  in the biased position, the locking pin  120  may have a plurality of flutes  122  formed in the locking pin  120  in which the release catch  142  is received. As a result, any effort to extract the pin  120  by pulling it away from the window frame  5  is resisted by contact between the flute wall and an opposing wall of the release catch that extends into the flute  122  as a result of the bias force applied by the spring  150 . It will be appreciated that while the locking pin  120  is shown and described as substantially cylindrical, any shape pin may be used and that any manner of applying a force to retain the locking pin  120  in its locked position may also be employed. The flutes  122  may be formed as grooves, threads or other features formed in the locking pin and may extend partially or entirely about the perimeter of the locking pin  120 . 
     Turning to  FIG. 4 , the bias force exerted by the spring  150  that holds the release  140  in contact with the locking pin  120  can be overcome by exerting a compression force larger than the bias force, for example, by squeezing the release  140  and the latch tab  112 . This force compresses the spring  150  and causes the release catch  142  to retreat from the flute  122  of the locking pin  120  in which it was situated. Once this first action is accomplished, the locking pin  120  is free to be pulled through its shaft  128  away from the window frame  5  as reflected in  FIG. 5  by a second action that unlocks the screen  10  for opening and/or removal. 
     In some embodiments, the locking pin  120  may include multiple flutes  122 . In that case, one of the flutes  122  may be positioned such that the release catch  142  is aligned with the additional flute when the locking pin  120  is in the open position. Thus, if the compression force is removed and the spring  150  returns the release  140  to its original biased position, the force now retains the locking pin  120  in the unlocked position. Thus, the user does not need to maintain the compression force while the screen  10  is being removed. This may be particularly useful if multiple latch assemblies  100  are used with a single security screen window  10 , so that each latch assembly can be sequentially moved from the locked to unlocked position, even if that requires closing one sash of the window and opening another to gain access to a different part of the screen  10 . 
       FIG. 5  also illustrates how a channel  126  formed in the locking pin  120  combined with a travel stop  160  can be used to define a distance of maximum travel for the locking pin  120  so that a user knows when the locking pin  120  has been moved a sufficient distance to fully extract it from the window frame  5  but without the need to pull the pin  120  all the way out of the latch housing  110 . 
     As shown in  FIGS. 3-5 , in some embodiments the flutes  122  may include a beveled surface  124  that matches a beveled surface  144  of the release catch  142  that together form opposing inclined planes in the direction of pin insertion into the window frame  5 . As a result, it may be possible to overcome the bias of the spring force during pin insertion without the need to compress the release  140  and latch tab  112 . Thus, the latch assembly  100  can be moved to the locked position with a single action, despite the need for two independent actions to open the latch assembly  100  into the unlocked position. 
       FIG. 6  illustrates another exemplary embodiment of a latch assembly  100 . In this embodiment, a spring loaded locking pin  220  is provided that is biased toward the unlocked position by a locking pin spring  222  that is held in the compressed state when in the locked position by the release catch  142 . As a result, when the release  140  and the latch tab  112  are squeezed to compress the spring  150  and the release catch  142  withdraws from the spring loaded locking pin  220 , the locking pin spring  222  urges the spring loaded locking pin  220  toward the unlocked position. As a result, the user does not need to manually withdraw it through the pin channel. 
     As also shown in  FIG. 6 , a second release mechanism, such as a second latch release  140   a  having its own release catch  142   a  and biased toward the locked position by a second spring  150   a  may be employed on the opposite side of the latch assembly  100 . While a second release mechanism can be used in any embodiment, it may be desirable in combination with those employing a spring loaded locking pin  220  so that a two-step release is still employed to provide a child-resistant latch assembly that can meet the safety standards described in ASTM F2090-10 as previously referenced with respect to other embodiments illustrated and described herein. 
     While the invention has been described with reference to particular embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.