Patent Publication Number: US-7722096-B2

Title: Latchbolt for a door lock assembly

Description:
BACKGROUND 
     The present invention relates to door lock assemblies, and more particularly to latchbolts for door lock assemblies. 
     Door lock assemblies typically include a latchbolt movably coupled to a door. The latchbolt engages a strike coupled to a door frame to prevent the door from being opened when the latchbolt is in a locked and extended position. Exit doors found in large facilities or public buildings typically include a push-bar that can be depressed to unlock the latchbolt thereby allowing a user to open the door. When the door returns to the closed position, the latchbolt returns to the locked and extended position to prevent the door from being opened unless the push-bar is depressed. 
     SUMMARY 
     In one embodiment, the invention provides a latchbolt configured for use with a door lock assembly. The door lock assembly is configured for interaction with a strike that is coupled to a door frame, and is operable to place the latchbolt in a locked configuration using the strike to generally prevent rotation of the door and an unlocked configuration to allow rotation of the door. The latchbolt includes a first member and a second member movably coupled to the first member. When the latchbolt is in the locked configuration the second member is movable relative to the first member from a first position to a second position in response to a predetermined force applied to the door. 
     In another embodiment the invention provides a door lock assembly configured for use with a door hingedly coupled to a door frame that includes a strike such that the door rotates about an axis between a closed position and an open position. The door lock assembly includes a latchbolt configured to engage the strike to substantially prevent rotation of the door from the closed position to the open position. An engagement point is defined as the point on the strike where the latchbolt contacts the strike when the door is in the closed position. An engagement angle is defined as the angle between a line that extends from the center of the strike through the engagement point and a plane that extends generally vertically and generally normal to the door frame. The latchbolt is configured to engage the strike in the closed position at one of a first engagement angle and a second engagement angle that is different from the first engagement angle. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a door assembly in an open position that employs a latchbolt embodying the present invention. 
         FIG. 2  is an enlarged side view of a portion of the door assembly of  FIG. 1  showing the door in a closed position. 
         FIG. 3  is a partial cross-sectional view of a portion of the door assembly taken through lines  3 - 3  of  FIG. 2  showing the latchbolt in a first position. 
         FIG. 4  is a perspective view of the latchbolt utilized by the door assembly of  FIG. 1  showing the latchbolt in the first position. 
         FIG. 5  is a side view of the latchbolt of  FIG. 4  showing the latchbolt in the first position. 
         FIG. 6  is a cross-sectional view of the latchbolt taken along line  6 - 6  of  FIG. 5  showing the latchbolt in the first position and a strike of the door assembly. 
         FIG. 7  is a cross-sectional view of the latchbolt taken along line  7 - 7  of  FIG. 5  showing the latchbolt in a second position and the strike of the door assembly. 
         FIG. 8  is a partial cross-sectional view of a portion of the door assembly taken through lines  8 - 8  of  FIG. 2  showing the door moving from the closed position to an open position. 
         FIG. 9  is a partial cross-sectional view of a portion of the door assembly taken through lines  9 - 9  of  FIG. 2  showing the door in the closed position and the latchbolt in the second position. 
         FIGS. 10   a - 10   c  illustrate a portion of the door assembly of  FIG. 2  showing the latchbolt rotating about a bridge axis as the door moves from the open position to the closed position. 
     
    
    
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
     The present invention will be described with reference to the accompanying drawing figures wherein like numbers represent like elements throughout. Certain terminology, for example, “upper”, “lower”, “right”, “left”, “clockwise”, and “counterclockwise” is used in the following description for relative descriptive clarity only and is not intended to be limiting. 
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a door assembly  10  that includes a door  12  and a lock assembly  13  coupled to the door  12 . The door  12  is hingedly coupled to a door frame  14  such that the door  12  can rotate about an axis  16  between a closed position and an open position. While the illustrated door assembly  10  is arranged such that the door  12  rotates or opens outwardly, in other constructions the door assembly can be arranged such that the door rotates or opens inwardly. 
     Referring to  FIGS. 1 and 3 , the door  12  includes an interior surface  18  and an exterior surface  20 . The door  12  can be made from any suitable material, such as wood, aluminum, steel, composite, etc., or any combination thereof. Furthermore, while  FIG. 1  illustrates a single door arrangement, one of skill in the art would realize that in other constructions the door assembly can include double and multiple door arrangements. 
     Referring to  FIG. 3 , the lock assembly  13  includes a cover  22 , an interior actuator  24 , an exterior actuator  26 , and a locking mechanism  28  that is generally enclosed within the cover  22 . The interior and exterior actuators  24 ,  26  are operable to actuate a locking mechanism  28 . The illustrated interior actuator  24  is a push-bar, and in other constructions, the interior actuator can be any suitable actuator, such as a rotatable handle and the like. The illustrated exterior actuator  26  is a rotatable handle, and in other constructions the exterior actuator can be any suitable actuator. In yet other constructions, the lock assembly may omit the exterior actuator, and in such constructions the door assembly can include an exterior handle that is relatively fixed with respect to the door. 
     The illustrated locking mechanism  28  includes a housing  30 , a bridge  31 , a locking member  32 , a control link  34 , and a latchbolt  36 . The housing  30  is coupled and fixed with respect to the door  12 . The illustrated bridge  31  is rotatably coupled to the housing a pin such that the bridge  31  rotates with respect to the housing  30  about an axis  37 . The locking member  32  is rotatably coupled to the housing  30  using a pin  38 . The control link  34  is slidably coupled to the housing  30  and connected to the interior actuator  24  and the exterior actuator  26 . 
     It should be understood that the locking mechanism can be any suitable locking mechanism such as the locking mechanism described in U.S. patent application Ser. No. 11/398,574, filed Apr. 5, 2006, the entire contents of which are hereby incorporated by reference. 
     Referring to  FIGS. 4-6 , the latchbolt  36  includes a first member  40  and a second member  42  movably coupled to the first member  40 . The illustrated first member  40  has a radiused or curved outer surface portion  44  and a generally flat outer surface portion  46 . The illustrated first latchbolt member  40  is generally hollow and defines a cavity  48  that receives the second latchbolt member  42 . The second latchbolt member  42  includes a curved outer surface  50  and a lip  52  formed at an end of the second member  42 . 
     An aperture  56  extends through first and second latchbolt members  40 ,  42 . The aperture  56  defines a latchbolt axis  58  that extends through the center of the aperture  56 . The latchbolt aperture  56  receives a pin  60  that rotatably couples first and second latchbolt members  40 ,  42  and rotatably couples the latchbolt  36  to the bridge  31 , which is rotatably coupled to the housing  30  of the locking mechanism  28  ( FIG. 3 ). While the illustrated latchbolt  36  is coupled to the housing  30  using the bridge  31 , in other constructions the latchbolt can be directly coupled to the housing, and the bridge can be omitted. In yet other constructions, the latchbolt can be coupled to any suitable member of the locking mechanism using any suitable connection. 
     Referring to  FIGS. 8 and 9 , while the illustrated second latchbolt member  42  rotates with respect to the first latchbolt member  40  about the same axis  58  about which the latchbolt  36  rotates with respect to the bridge  31 , in other constructions, the second latchbolt member  42  may rotate with respect to the first member  40  about an axis other than the axis  58  about which the latchbolt  36  rotates with respect to the bridge  31 . In such constructions, the second latchbolt member  42  can rotate with respect to the first latchbolt member  40  about any suitable axis. In yet other constructions, the second latchbolt member  42  can be slidably coupled to the first latchbolt member  40  such that the second latchbolt member  42  slides into and out of the cavity  48  defined by the first latchbolt member  40 . 
     Referring to  FIG. 6 , the latchbolt  36  further includes a biasing member  62  that includes a first end  64  and a second end  66 . The biasing member  62  is located within the cavity  48  between the first and second latchbolt members  40 ,  42  such that the first end  64  contacts the first latchbolt member  40  and the second end  66  contacts the second latchbolt member  42 . While the illustrated biasing member  62  is an elastomeric material such as butadiene rubber, in other constructions, the biasing member can be formed from any suitable material and may take other forms. For example, in other constructions the biasing member may include a spring, such as a coil spring, torsion spring, and the like. 
     Referring to  FIGS. 1 and 2 , a strike  68  is coupled to the door frame  14 , and in the illustrated construction the strike  68  is located on a vertical member of the door frame  14 , opposite the axis  16 . In other constructions, the strike  68  can be located at any suitable location on the door frame  14 , such as along an upper or lower member of the door frame  14 . Furthermore, while the illustrated door frame  14  includes one strike, in other constructions the door frame can include more than one strike. 
     Referring to  FIGS. 3 and 6 , in operation, the latchbolt biasing member  62  biases the second latchbolt member  42  in a direction out of the cavity  48  or in a direction about the latchbolt axis  58  indicated by the arrow  71  in  FIG. 6 .  FIGS. 3 and 6  illustrate the second latchbolt member  42  in a fully extended or a first position such that the lip  52  of the second latchbolt member  42  abuts a corresponding portion of the first latchbolt member  40  that acts as a stop to prevent further rotation of the second latchbolt member  42  with respect to the first latchbolt member  40  in the direction indicated by the arrow  71 . 
     Referring to  FIGS. 3 and 6 , when the door  12  is in the closed position the latchbolt  36  is in an extended position such that the curved surface  50  of the second latchbolt member  42  contacts the strike  68 . Furthermore, the locking member  32  contacts the latchbolt  36  to lock the latchbolt  36  in the extended position ( FIG. 3 ) when the door  12  is closed. 
     Referring to  FIGS. 3 and 6 , an engagement point  78  is defined as the point on the strike  68  that contacts the latchbolt  36 . An engagement angle α is defined as the angle between a line  80  that extends from the center of the strike  68  through the engagement point  78  and a plane  82  that extends generally vertically and generally normal to the door frame  14 .  FIGS. 3 and 6  illustrate the second latchbolt member  42  in the fully extended, or first position and the engagement angle α is about 60 degrees. In other constructions, the engagement angle, with the second latchbolt member  42  in the first position, can be any suitable angle, such as engagement angles between about 30 degrees and about 80 degrees. 
     Referring to  FIG. 3 , in the illustrated construction, the lock assembly  13  can be placed in a locked or an unlocked configuration. If the lock assembly  13  is in the locked configuration a user is unable to actuate the locking mechanism  28  using the exterior actuator  26 . However, the lock assembly  13  can be actuated using the interior actuator  24 . The user can actuate the locking mechanism  28  using either the interior or exterior actuators  24 ,  26  if the lock assembly  13  is in the unlocked configuration. 
     Referring to  FIG. 8 , with the lock assembly  13  in the unlocked configuration, the user rotates the exterior actuator  26  to move the control link  34  in a direction indicated by an arrow  72 . Likewise, the user could depress the interior actuator  24  to produce the same movement of the control link  34 . Moving the control link  34  in the direction of the arrow  72  rotates the locking member  32  to disengage the locking member  32  from the latchbolt  36 . The user then pulls the door  12  in a direction indicated by an arrow  74  to open the door  12 . As the user opens the door  12 , the latchbolt  36  rotates about the latchbolt axis  58  into a recessed position to allow the user to open the door  12 . 
     In the illustrated construction, as the door  12  rotates from the open position to the closed position, the strike  68  engages the curved surface  44  of the first latchbolt member  40  and forces the latchbolt  36  and the bridge  31  to rotate about the axis  37 , such that the latchbolt  36  rotates into the recessed position allowing the door  12  to rotate to the closed position. When the door  12  is in the closed position, the curved surface  50  of the second member  42  enables the latchbolt  36  to rotate about the axis  37  back into the extended position while maintaining contact with the strike  68 . 
     Referring to  FIG. 9 , with the door  12  in the closed position and the lock assembly  13  in the locked configuration, the user is unable to move the control link  34  in the direction indicated by the arrow  72  by rotating the exterior actuator  26 . Therefore, the locking member  32  remains engaged with the latchbolt  36  thereby locking or preventing the latchbolt from rotating about the latchbolt axes  58  or  37  preventing the door  12  from opening. 
     Referring to  FIGS. 7 and 9 , with the door  12  in the closed position and the lock assembly  13  in the locked configuration, when a force is applied to the door  12  in a direction that tends to rotate the door  12  toward the open position, the second latchbolt member  42  rotates with respect with the first latchbolt member  40 . One example of such a force is illustrated in  FIG. 9  and includes an unauthorized user pulling the exterior actuator  26  in the direction indicated by the arrow  74 . When the force applied to the door  12  is greater or equal to a predetermined force, the second latchbolt member  42  rotates into a second or retracted position. 
       FIG. 7  illustrates the second latchbolt member  42  in the retracted or second position. In the second position the strike  68  engages the generally flat portion  46  of the first latchbolt member  40  to define an engagement angle α of about 90 degrees. While the illustrated latchbolt  36  is configured to have the engagement angle α of about 90 degrees when the second latchbolt member is in the second position, in other constructions, the engagement angle can be somewhat greater or less than 90 degrees. For example, in one construction, the engagement angle can be between about 80 degrees and about 110 degrees when the second latchbolt member is in the second position. 
     Engagement angles α that are about 90 degrees provide a more secure locking configuration than engagement angles that are less than about 90 degrees. When the engagement angle is less than 90 degrees the force applied to the door may spread or move the door frame members apart and thereby compromise the security provided by the door. 
     The predetermined force that moves the second member  42  from the first position ( FIG. 6 ) to the second position ( FIG. 7 ) can be any suitable force and can vary depending upon the application of the door lock assembly  13  and the type of door, door frame, strike, etc. Therefore, the biasing member  62  can be selected with a desired stiffness to determine the predetermined force that moves the second latchbolt member  42  from the first position ( FIG. 6 ) to the second position ( FIG. 7 ). 
     Various features and advantages of the invention are set forth in the following claims.