Abstract:
A mechanical latch assembly for a retractable door or window system is described. The latch assembly includes a latch subassembly mountable between inner and outer door handles and a catch subassembly mountable on a support surface. When the retractable door or window is adjusted to a fully closed position, the latch and catch subassemblies may be releasably coupled together by engaging a latch and a catch bar. A safety catch may be optionally deployed for maintaining the latch in an engaged position. The latch subassembly may include a pair of rotatable cassettes and a corresponding pair of thumb levers for rotating the cassettes against the bias of a spring to move the latch from the engaged to a disengaged position. The latch may be disposed on one of the rotatable cassettes. The catch assembly may include optional brackets for mounting the catch assembly on a door jamb, pocket door frame, another door handle or other suitable support surface.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the priority of U.S. application No. 61/106,105 filed 16 Oct. 2008 and entitled MECHANICAL LATCH ASSEMBLY FOR RETRACTABLE SCREEN DOORS AND WINDOWS, which is hereby incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    This application relates to a mechanical latch assembly for retractable screen doors and windows. 
       BACKGROUND 
       [0003]    Most commercially available retractable screen doors use a magnetic latching system. Such magnetic latches are sometimes difficult for elderly or infirm users to easily open. Also, such systems also do not provide any measure of security since they can not be locked in the closed position. In outdoor applications, the metal magnetic components are also prone to gradual corrosion. 
         [0004]    Some mechanical latch systems are known in the prior art but they are not commonly used in respect of retractable door and window applications. In the prior art, mechanical latches are typically mortised into an aluminum door extrusion at predetermined locations and are therefore not easily adapted for different door or window configurations. 
         [0005]    The need has therefore arisen for a more versatile mechanical latch assembly specifically designed for retractable screen door and window applications. A non-limiting example of such an application is the MIRAGE™ retractable door system sold by the applicant. 
         [0006]    The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings. 
       SUMMARY 
       [0007]    The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements. 
         [0008]    In accordance with the invention, a latch assembly for a retractable door or window closure is provided, the closure having a first handle and a second handle disposed on opposite sides of the closure for moving the closure between retracted and extended positions. The latch assembly includes a (a) latch subassembly disposed between the first and second handles, the latch subassembly comprising (i) a latch disposed on a rotatable cassette, and (ii) at least one lever for actuating rotation of the cassette to move the latch between an engaged and a disengaged position; and (b) a catch subassembly mountable on a support surface for releasably engaging the latch when the closure is in the extended position and the latch is moved to the engaged position. 
         [0009]    In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed descriptions. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]    Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. 
           [0011]      FIG. 1  is a front view of a conventional retractable screen door in a partially extended position. 
           [0012]      FIG. 2  is a first perspective, exploded view of the mechanical latch assembly of the present invention showing one embodiment of the latch and catch subassemblies. 
           [0013]      FIG. 3  is a perspective, exploded view of the latch subassembly. 
           [0014]      FIG. 4  is another perspective, exploded view of the latch subassembly. 
           [0015]      FIG. 4(   a ) is an enlarged perspective view of the safety catch of the latch subassembly. 
           [0016]      FIG. 5  is a perspective, exploded view showing embodiments of the catch subassembly, including some alternate mounting brackets. 
           [0017]      FIG. 6  is another perspective, enlarged, exploded view of the catch subassembly embodiments of  FIG. 5 . 
           [0018]      FIG. 7  is a further enlarged perspective view of a handle and the latch subassembly. 
           [0019]      FIG. 8  is an enlarged, perspective view of a pair of cassettes and a shaft connector of the latch subassembly. 
           [0020]      FIG. 9  is an enlarged perspective of the latch subassembly mounted on a door handle for releasably engaging a catch subassembly. 
           [0021]      FIG. 10  is a further perspective view of the latch subassembly mounted on opposed door handles for releasably engaging a catch subassembly mounted on a door jamb. 
           [0022]      FIG. 11  is an enlarged perspective of the latch subassembly mounted on a door handle for releasably engaging a catch subassembly mounted on another door in a French door application. 
           [0023]      FIG. 12  is an enlarged, cut-away view of a spring-loaded cassette of the latch subassembly positionable within a door handle. 
       
    
    
     DESCRIPTION 
       [0024]    Throughout the following description specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense. 
         [0025]    This application relates to a mechanical latch assembly generally designated  10  for a retractable closure, such as a retractable screen door  20  or window adjustable between a retracted and an extended position. A non-limiting example of such a closure is the MIRAGE™ retractable screen door system sold by the applicant, as shown in  FIG. 1 . As will be appreciated by a person skilled in the art, such doors can be installed to fit many different door applications, including in-swing or out-swing doors, patio doors, pocket doors, entrance doors and French double doors. When not in use, the screen doors retract within a housing and are substantially hidden from view. 
         [0026]    As shown in  FIG. 2 , latch assembly  10  includes a latch subassembly  12  and a catch subassembly  14 . Latch subassembly  12  extends between a first handle  16  and a second handle  18  disposed on opposite sides of door  20 . For example, first handle  16  could be disposed on the inner surface of door  20  and second handle  18  could be disposed on the outer surface of door  20  ( FIG. 10 ). As described below, catch subassembly  14  may be disposed on a door jamb or another support surface for coupling to latch subassembly  12  when door  20  is in its extended position. 
         [0027]    Handle  16 ,  18  may be coupled together at the desired location on door  20  by means of fasteners  22 , as shown in  FIGS. 2-4 . The upper fastener  22  also functions as an axle for latch subassembly  12 . After each fastener  22  has been inserted, plugs  23  may be inserted in an end portion of a handle  16 ,  18  to hide the heads of the fasteners  22 . In the illustrated embodiment, plugs  23  are insertable into handle  18  only and the threaded end portion of each fastener  22  is received within the other handle  16 . 
         [0028]    Latch subassembly  12  further includes a pair of cassettes  26  each received within a cavity  28  formed in a respective handle  16 ,  18 . Each cassette  26  comprises a first annular plate  32  and a second annular plate  34  which may be matingly coupled together, as best shown in  FIGS. 7 and 8 . For example, in the illustrated embodiment, first plate  32  includes a pair of pins  36  which are each received within a mating aperture  38  in second plate  34 . At least one of the cassettes  26  comprises a spring  30  which is captured between first plate  32  and second plate  34 . First plate  32  includes a rim  40  for receiving spring  30 . In one embodiment of the invention, the end portions of spring  30  are each positioned underneath a respective pin  32 . As best shown in  FIG. 12 , one end of spring  30  fits underneath a ledge located within a handle cavity  28  to tension spring  30  when cassette  26  is rotated. Optionally, spring  30  may be tensioned when cassette  26  is rotated in either direction. 
         [0029]    As described further below, second plate  34  may also include a hook-shaped latch  42  ( FIGS. 3 and 4 ) and a thumb lever  44  for activating rotation of cassette  26  against the bias of spring  30 . As shown best in  FIG. 8 , one of cassettes  26  may comprise a second plate  34  having a lever  44  but no spring  30  or latch  42 . Each lever  44  is connected to a respective second plate  34  with a projecting post  43 . In one embodiment of the invention, plate  34 , post  43  and lever  44  (and optionally latch  42 ) may be one integral component part. 
         [0030]    The pair of cassettes  26  are coupled together with a connector shaft  46 , as shown best in  FIG. 8 . In the illustrated embodiment, shaft  46  includes a central portion  48  and two hexagonal-shaped end portions  50  which are each shaped to be received within mating apertures  52  formed in central portions of plates  32 ,  34 . As will be apparent to a person skilled in the art, the size and shape of end portions  50  and apertures  52  may vary without departing from the invention. As shown best in  FIGS. 2-4  and  12 , upper fastener  22  functioning as the axle for latch subassembly  12  extends through the interior of connector shaft  46  and apertures  52 . Connector shaft  46  ensures that rotational movement of one cassette  26  relative to a respective handle  16 ,  18  will be translated to the other cassette  26  of latch subassembly  12 . Thus rotational movement of latch  42  may be actuated from either side of door  20 . Since cassettes  26  are interchangeable, this allows latch  42  to be located on the right side, left side, inside or outside of the door screen depending upon user or installer preference. 
         [0031]    As shown in the drawings, each handle  16 ,  18  has first and/or second slot openings  47  for receiving a respective thumb lever  44  and latch  42 . In some configurations a handle opening  47  may be filled with a plug  45 . For example, a plug  45  can remain in place if the handle  16 ,  18  receives a cassette  26  which does not include a second plate  34  bearing a latch  42 . 
         [0032]    Latch  42  is adjustable between engaged and disengaged positions when door  20  is in the extended position. As shown in  FIG. 9 , when door  20  is fully extended, latch  42  may latchingly engage catch subassembly  14 . As described further below, catch subassembly  14  may be mounted on a support surface such as a door jamb or pocket door frame or another door in a French door application. In one embodiment of the invention, catch subassembly  14  includes a bracket  54  for receiving a catch base  56  and a catch cover  58 . Catch cover  58  includes a catch bar  60  for releasably engaging latch  42 . In one embodiment of the invention base  56  and cover  58  may be configured to snap together. Fasteners  62  may also be provided to aid in coupling base  56  and cover  58  to a bracket  54  or other support surface, as shown in  FIGS. 5 and 6 . Additional fasteners  64  may be used for mounting bracket  54  on a support surface, such as a door jamb, at the desired location. Optionally, a pair of springs  67  may be disposed between base  56  and cover  58  for biasing cover  58  outwardly. Thus the exact position of catch bar  60  relative to base  56  may be finely adjusted by turning fasteners  62 . 
         [0033]    As will be apparent to a person skilled in the art, catch subassembly  14  may be mounted in many different configurations and orientations. For example, subassembly  14  may be mounted on an outer or inner surface of a door jamb ( FIG. 10 ) using bracket  54  and fasteners  64 . In the case of some applications, such as the frame of a pocket door, bracket  54  may not be required ( FIG. 9 ) and base  56  and attached cover  58  may be mounted directly on the support surface. In the case of a sliding French door application, bracket  54  and base  56  may be replaced with a modified bracket  54   a  and base  56   a  for coupling the latch subassembly to a door handle  16 ,  18  ( FIGS. 5 ,  6  and  11 ). Thus the shape and orientation of the component parts of catch subassembly  14  may vary depending upon the application. 
         [0034]    As shown best in  FIGS. 4 and 4   a , latch subassembly  12  may further include a safety catch  66  for maintaining latch  42  in the engaged position. Catch  66  may include a thumb slide  67  and a tab  68  which releasably engages a lever  44  of an adjacent cassette  26  (e.g. by blocking movement of lever post  43 ) and hence constrains rotational movement of cassettes  26  and latch  42 . Each handle  16 ,  18  includes a small, scored knock-out panel  69  for exposing a slot for slidably receiving catch  66  ( FIGS. 2 and 3 ). For example, panel  69  may be removed by an installer using a utility knife and needle nose pliers. Catch  66  may be mounted to optionally engage the cassette  26  comprising latch  42  or the opposite cassette  26 . Thus, in one configuration, latch  42  may be disposed on an outer side of a door  20  and catch  66  may be disposed on an inner side of a door  20 . Safety catch  66  is optionally provided to offer users a measure of security, but it is not intended to function as robust lock preventing forceful opening of door  20 . 
         [0035]    In use, latch subassembly  12  and catch subassembly  14  are assembled in the desired configuration as described above and illustrated in the drawings. When retractable door  20  is moved by a user toward its fully extended position ( FIG. 9 ), latch  42  of latch subassembly  12  rides up and engages bar  60  of catch subassembly  14  (i.e. latch subassembly  12  is self-latching). Optionally, latch  42  may be maintained in the engaged position by sliding catch  66  to its catched position to restrain rotation of cassettes  26 . Door  20  may be opened by sliding catch  66  to the disengaged position and depressing a thumb lever  44  (from either side of door  20 ) against the bias of spring  30  to raise latch  42  away from bar  60 . This disengages latch  42  and allows the user to return door  20  to its retracted position. 
         [0036]    As explained above, latch assembly  10  is sufficiently versatile to suit both single door and French door applications. Since cassettes  26  are interchangeable, latch  42  may be optionally located on the right side, left side, inside or outside of the screen door depending upon user or installer preference. Moreover, safety catch  66  may be disposed on either the same side as latch  42  or the opposite side of the door  20 . The ability to install latch assembly  10  in many different combinations and permutations is an important feature of the present invention. 
         [0037]    Although mechanical latch assembly  10  has been described above in respect of a retractable screen door application, it should be apparent to a person skilled in the art that the same mechanism can be used in regard to retractable windows or other screened or non-screened closures. 
         [0038]    While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the following appended claims of the invention and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.