Abstract:
A latching system for locking in the closed position movable elements such as doors and drawers mounted in cabinet frames for movement between open and closed positions in which a latch element is attached to the cabinet frame and is provided with a cantilevered portion having an aperture therein which engages a pin in the movable element to releasably lock the movable element in the closed position against randomly applied forces such as earthquake generated forces and the like.

Description:
RELATED APPLICATION  
       [0001]    This application is based on and claims priority with respect to provisional patent application No. 60/220,352, filed Jul. 24, 2000 for HOUSEHOLD CABINET SAFETY LATCH in the name of Robert Ernest Patton. Priority is further claimed based on Disclosure Document number 477414 filed Jul. 24, 2000. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to locking systems for movable elements mounted in cabinet frames and movable between open and closed positions such as cabinet doors and drawers and, more particularly, to locking systems of the aforementioned type that are capable of automatically locking cabinet doors and drawers and the like upon the closing thereof against earthquake type disturbances and randomly applied opening forces.  
         BACKGROUND OF THE INVENTION  
         [0003]    Today&#39;s mass-produced cabinets, such as wall cabinets used in typical household kitchens for example, are not usually provided with locking devices to hold the doors and drawers thereof in the closed position against randomly applied forces such as may result from earthquake disturbances or against attempts by children to gain access thereto. Locking systems for such applications are available in the prior art but these are complicated, expensive, generally cumbersome to install and operate and are typically not aesthetically pleasing.  
         SUMMARY OF THE INVENTION  
         [0004]    The present invention provides a simple and inexpensive locking system that operates automatically upon closing to lock cabinet doors and drawers in the closed position, that is easy to install and operate and that has a low visual impact on the overall appearance of such installations. The locking system of the present invention operates as a positive latch and is earthquake resistant because of its positive action in locking. It is also resistant to random opening forces such as may be applied by small children, for example.  
           [0005]    The locking system of the present invention operates automatically upon the closing of the door and/or drawer elements against the cabinet frame to lock the door and/or drawer elements in the closed position. The locking function that is automatically activated by the closing action is capable of being readily released by a simple hand and finger movement to release the locking action thereof and permit easy opening of the latched door and/or drawer elements 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    [0006]FIG. 1 is a cross sectional side view of one embodiment of the present invention as installed on cabinet door and frame elements shown in the open position and at the point of first contact between the locking elements as the door moves to the closed position;  
         [0007]    [0007]FIG. 2 is another cross sectional side view of the embodiment of FIG. 1 showing the elements in the closed position.  
         [0008]    [0008]FIG. 3 is a perspective view of one of the latch elements of the embodiment of FIG. 1;  
         [0009]    [0009]FIG. 4 is another perspective view of the latch element of FIGS. 1 and 2;  
         [0010]    [0010]FIG. 5 is a cross sectional side view of the latch element shown in FIGS. 3 and 4; and  
         [0011]    [0011]FIG. 6 is cross sectional view of the embodiment of FIGS. 1 and 2 showing the engagement of the elements of the locking system when the cabinet door is moved toward the open position when the locking system is in the locked condition. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0012]    Referring now to the embodiment of FIGS. 1 and 2, there is shown in cross sectional format a cabinet frame  10  and a movable element in the form of a cabinet door  12 . The door  12  is hinged to the frame  10  in the usual and well-known manner (not shown) and is shown in FIG. 1 the open position with the door  12  spaced away from the frame  10 . The door  12  is moved to the left toward the frame  10  for closing. The closed position is shown in FIG. 2.  
         [0013]    In the embodiment shown in FIGS. 1 and 2, the lower surface of a cabinet opening is defined by a surface  14  of the frame  10 . The door  12  has a lower surface  16  on which is mounted a pin element  18 , shown in FIGS. 1 and 2 in the form of a screw with a body portion  19  and a head portion  20 . The pin  18  extends from the lower surface of the door  12  so that the head portion  20  is spaced away from the lower surface  16 .  
         [0014]    A first latch element  22  is attached to the frame  10  by means of a flat head mounting screw  24 . The latch element  22  is shown in further detail in FIGS.  3 ,  4  and  5 . Referring to FIGS. 3, 4 and  5 , latch element  22  is provided with a countersunk hole  26  for receiving the mounting screw  24  so that when secured in position, the face of the flat head of the mounting screw  24  is flat against the surface of the latch element  22 .  
         [0015]    The latch element also includes an extending cantilevered portion  23  with an aperture  28  for capturing the pin element  18  as will be explained below in connection with the further description of the embodiment of FIGS. 1 and 2. The latch element also includes a resilient inclined tab  30  portion which is engaged by the head portion  20  of the pin  18  during closing as will be explained below.  
         [0016]    Referring now to FIG. 1, as the door is moved to the left toward the closed position, the head portion  20  of the pin  18  contacts the upper surface of the resilient inclined tab  30 . The point of first contact between the head portion  20  and the inclined tab portion  30  is shown in FIG. 1. As the door continues to move to the left from the position shown in FIG. 1 toward the closed position, the head portion  20  further depresses the resilient inclined tab portion  30  and rides up the upper surface thereof to reach the closed position shown in FIG. 2 with the head portion  20  snapping into the locked position in aperture  28  as shown in FIG. 2.  
         [0017]    The locking system elements are positioned relative to each other such that with the elements in the closed position as shown in FIG. 2, the pin  18  extends below the surface of the aperture  28  so that the pin  18  is captured in the aperture  28 . In this position, outward movement of the door  12  is limited by the engagement of the pin  18  with the surface of the aperture  28 . In the preferred embodiment as shown, the head  20  assists and makes more secure the capture of the pin  18  within the aperture  28  by engaging the under surface of the inclined tab portion  30  at the aperture  28  upon outward movement of the door  12  to thereby further prevent the escape of the pin from the aperture  28 .  
         [0018]    The locking system of the embodiment of FIGS. 1 and 2 therefore provides for automatic locking of the system in the closed position through the movement of the door  12  into the closed position. As the head portion  20  of the pin  18  rides over the surface of the resilient inclined tab portion  30 , it snaps into the locked position shown in FIG. 2 when the head portion  20  reaches the aperture  28  and falls into the captured position as shown. That is, the pin  18  moves the inclined tab portion to a fully deflected position and then when the pin  18  registers with the aperture  28 , the inclined tab portion snaps from the deflected position into the locked position with the pin captured within the aperture  28 .  
         [0019]    If the door  12  is moved toward the open position with the elements of the system in the locked condition as shown in FIG. 2, the underside of the head portion  20  of the pin  18  will engage the under surface of the aperture  28  as shown in FIG. 6 so that the pin  18  is firmly captured with the edge of the head portion under the edge of the aperture  28  and held against escape from the aperture in a direction parallel to the axis of the pin  18 .  
         [0020]    The latch element  22  is preferably formed in a single piece entirely of a flexible material, such as a molded plastic material, so that the entire extending portion of the latch element extending outwardly from the frame  10  acts as a flexible cantilever with the inclined tab portion  30  thereof acting as a cam surface for the engagement of the head portion  20  of the pin  18 . The term “flexible” as used herein means that the material returns to its original position when released after being deflected, in an amount as described herein for operation of the locking system of the invention, and that the material does not retain a permanent set after release of the deflecting force.  
         [0021]    It is understood that the presence of the head portion  20  on the pin  18  represents a preferred embodiment and that the engagement of the pin  18  with the aperture  28  will by itself still function to limit the outward movement of the door  12  from the closed position even without the head portion  20 . However, the head portion  20  provides a further degree of locking security as explained above and this embodiment is therefore preferred.  
         [0022]    It is to be noted that in the preferred embodiment as presented herein, there are no moving parts other then the flexing of the latch element as the door  12  is moved to the closed position and that the attainment of the locked status is automatic with the closing of the door  12 .  
         [0023]    The resilient inclined tab portion  30  extends beyond the outer surface of the door  12  in the locked position as shown in FIG. 2 so that it is accessible for manual downward deflection and release. Release of the system from the locked position is realized by pressing down with a simple finger movement to downwardly deflect the extending portion of the resilient inclined tab portion  30  and thereby release the pin  18  and its head portion  20  from the aperture  28 , permitting outward movement of the door  12 .  
         [0024]    The locking system of the invention may be mounted at any point on the frame  10  and the door  12  so long as the elements are aligned to interact with each other upon closing. In many cases, the bottom edges of the door  12  will be preferred both from the standpoint of appearance and also from the standpoint of ease of access for release.  
         [0025]    The locking system of the invention can also be mounted on drawers to interact between the drawers and the frame in which they are mounted to lock the drawers in the closed position. In such an application, the cabinet frame would be represented by the element  10  and the drawer would be represented by the element  12  so that the locking system of the invention will function in the same manner as the embodiment presented herein. The system is generally applicable to the locking of movable elements such as drawers or doors mounted in a cabinet frame and movable between open and closed positions in the frame.  
         [0026]    It is understood that the pin  18  with the body portion  19  and the head portion  20  can be in a form other than the screw element shown in the embodiment of FIGS. 1 and 2 although the screw element, which forms both the pin  18  and the head portion  20 , represents a simple and inexpensive option and is easy to attach to the door or drawer element  12 . The aperture  28  in the latch element  22  may also take different forms and still function in the manner presented herein.  
         [0027]    The term “pin” as used herein means any form of protrusion or extension capable of registering within the aperture  28  and being restrained therein to prevent movement from the closed position. Similarly, the term “aperture” as used herein means any form of depression or opening capable of receiving the pin on the movable element to capture the same and prevent movement from the closed position.  
         [0028]    Although the term “pin” is thus defined, in the preferred embodiment the diameter or width of the head portion  20  must be greater than the diameter or width of the body portion  19  of the pin and the diameter or width of the aperture  28  must be slightly greater than the diameter or width of the head portion  20  in order to allow the head portion to enter the aperture. This relationship of the diameters or widths of these elements allows the head portion  20  to engage the underside of the aperture  28  when the body portion  19  of the pin  18  is up against the edge of the aperture  28  restraining lateral movement of the door  12 , thereby preventing extraction of the pin  18  from the aperture in the direction parallel to the axis of the pin. It is also preferable in this embodiment that the under surface of the head portion  20  be flat and substantially perpendicular to the axis of the pin body portion  19  so that this flat surface engages the underside  32  of the edge of the aperture  28  in a manner firmly holding the pin  18  within the aperture  28  when the door  12  is moved toward the open position. This can be observed in FIG. 2 wherein it can be seen that the flat underside of the screw head portion  20  will engage the underside  32  of the edge of the aperture  28  when the door  12  is moved to the right toward the open position. The head portion  20  of the pin  18  is thus captured under the edge of the aperture  28  when the door  12  is moved toward the open position, thereby preventing the extraction of the pin  18  from the aperture  28 .  
         [0029]    Various modifications and applications of the invention will occur to those skilled in the art. It is therefore to be understood that the scope of the invention is not limited to the preferred embodiment which is presented herein for purposes of full disclosure thereof and not by way of limitation of scope.