Patent Publication Number: US-10774565-B2

Title: Pivotable bolt

Description:
FIELD OF THE INVENTION 
     The invention relates to lock assemblies. More specifically, the invention relates to a deadbolt and a latch for use in mortise lock assemblies. 
     BACKGROUND OF THE INVENTION 
     Mortise locks are well known devices used to latch swinging doors in a closed position. A typical mortise lock includes a lock body in which the moving components of the lock are disposed and a strike plate. The lock body is typically installed in a mortise (or pocket) that has been cut in the material of a door. The strike plate is typically installed on the doorframe in a position appropriate for it to interact with the lock body. The strike plate includes one or more openings for receiving one or more latches or deadbolts from the lock body. These latches and deadbolts serve various purposes but generally are intended to latch or lock the door in a closed position. 
     Mortise locks usually include a latch for securing a door in a closed position. The latch has an extended position in which the latch protrudes from the lock body and into an opening of the strike plate. The latch can be moved into a retracted position by turning the door handle which permits the door to be opened. In many locks, the latch is biased by a spring into the extended position. 
     Mortise locks also often include a deadbolt to secure the closed and latched door against attempts to force the door open. Typically, a deadbolt is extended and retracted by the rotational movement of a lock cylinder in the lock body. When the lock cylinder is rotated, the deadbolt moves between a retracted position in which the deadbolt is within the lock body, and an extended position in which the deadbolt protrudes from the lock body and into an opening of the strike plate. Because the deadbolt is typically constructed using strong, durable materials, it provides better resistance to attempts to open the door by force than a typical door latch. 
     The need to secure a door against forcible attempts to open it takes on enhanced importance in some applications. For example, in detention-type applications, in which possibly violent and/or dangerous persons must be detained behind a swinging door, the strength of a deadbolt to resist force becomes paramount. Other applications include residential doors in high-crime areas, designated “safe rooms” in schools, houses, or other buildings, and various applications related to military, law enforcement, and correctional facilities. 
     Standards organizations—such as ASTM International—have developed test methods and standards for classifying the strength of bolt designs. (Throughout this application, the term “bolt” is used to refer generically to both deadbolts and latches). These include standards for detention and correctional facilities. For example, STM Standard F1577 relates to standard test methods for detention locks for swinging doors. Among these standard tests is an impact test designed to evaluate the capability of a detention lock to resist repeated impact forces. 
     The need for high-strength bolt assemblies has been typically addressed by using higher strength materials for the deadbolt, latch, and/or other impact bearing components. Other approaches use larger sized components, such as a larger deadbolt or latch, to increase the strength of the lock. These approaches have been generally unsuccessful. It has become apparent that the overall size of a door lock intended to be handled by humans imparts a practical limit on how strong a conventional deadbolt or latch can be. There is a limit on the size that a deadbolt or latch can be for use in such a door, such that even use of the strongest material is not sufficient to withstand impacts that may be applied to the door. These traditional approaches to higher strength locks are not known to conform to known standards for detention and correctional facilities. 
     Accordingly, there is a need in the art for a lock design with improved resistance to forceful impacts. What is needed is a lock design that conforms to known standards for high-strength deadbolt assemblies. What is further needed is for such a design to be usable with typical mortise lock arrangements for swinging doors. What is further needed is for such a design to be simple and inexpensive to manufacture and install. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a lock that will have improved resistance to forceful impacts. 
     It is an additional object of the present invention to provide a lock that conforms to known standards for high-strength lock assemblies. 
     It is an object of the present invention to provide a deadbolt and latch for use with traditional mortise lock arrangements. 
     It is a further object of the present invention to provide such a deadbolt, latch, and lock that is relatively simple and inexpensive to manufacture and install. 
     These and other objects are at least partially achieved by provision of embodiments of the present invention. Embodiments of the invention permit the bolt and the tailpiece to pivot relative to one another about an axis that is substantially parallel to the plane of the door and substantially perpendicular to the axis along which the bolt moves as it is extended and retracted. 
     According to a first embodiment, a bolt assembly for securing a door is provided. The assembly comprises a bolt, comprising a movement axis along which the bolt travels when the bolt is extended and retracted; a tailpiece; and a pin, comprising a longitudinal axis. The pin connects the bolt and the tailpiece such that the longitudinal axis is substantially parallel to the plane of the door and is substantially perpendicular to the movement axis and such that the bolt and tailpiece are permitted to pivot with respect to each other about the longitudinal axis. 
     In some embodiments, the bolt is a deadbolt. In some embodiments, the tailpiece and pin are integral. In some embodiments, the deadbolt comprises a cylindrical hole to receive the pin. In some embodiments, the deadbolt comprises a slot formed in the portion of the deadbolt through which the cylindrical hole passes, and the slot is positioned in a plane that is substantially perpendicular to a central axis of the cylindrical hole. In some embodiments, the pin comprises a notch positioned to correspond to the slot when the pin is disposed in the cylindrical hole, and the assembly further comprises a clip securable to the notch for hindering removal of the pin from the cylindrical hole. In some embodiments, the tailpiece comprises a curved surface adjacent to the pin. 
     In some embodiments, the bolt is a latch. In some embodiments, the latch comprises a cavity at least partially shaped as a sphere adapted to receive an end of the tailpiece comprising a curved surface. 
     According to a second embodiment of the present invention, a lock assembly for securing a door is provided, comprising a body, adapted for installation in a mortise; a bolt, comprising a movement axis along which the bolt travels when the bolt is extended and retracted and a hole formed along an axis that is substantially perpendicular to the movement axis; and a tailpiece, disposed in the body and adapted to impart lateral movement along the movement axis to the bolt; a pin disposed in the body and comprising a longitudinal axis. The pin connects the bolt and the tailpiece such that the longitudinal axis is substantially parallel to the plane of the door and is substantially perpendicular to the movement axis and such that the bolt and tailpiece are permitted to pivot with respect to each other about the longitudinal axis. 
     In some embodiments, the pin and hole are substantially cylindrical. In some embodiments, the tailpiece comprises a curved surface adjacent to the pin. In some embodiments, the bolt is a deadbolt. In some embodiments, the bolt comprises a slot formed in the portion of the bolt through which the hole passes, and the slot is positioned in a plane that is substantially perpendicular to a central axis of the hole. In some embodiments, the pin comprises a notch positioned to correspond to the slot when the pin is disposed in the hole, and the assembly further comprises a clip securable to the notch for hindering removal of the pin from the hole. In some embodiments, the bolt is a latch. 
     According to a third embodiment of the present invention, a lock assembly for securing a door is provided. The lock assembly comprises: a body, adapted for installation in a mortise; a deadbolt, at least partly disposed in the body and movable along a first movement axis; a first tailpiece, disposed in the body and adapted to translate the rotational movement of a lock cylinder into lateral movement of the deadbolt along the first movement axis; and a first pin, comprising a first longitudinal axis and being disposed in the body such that the first longitudinal axis is substantially parallel to the plane of the door and substantially perpendicular to the first movement axis. The assembly further comprises: a latch, at least partly disposed in the body and movable along a second movement axis; a second tailpiece, disposed in the body and adapted to translate the rotational movement of a follower into lateral movement of the latch along the second movement axis; and a second pin, comprising a second longitudinal axis and being disposed in the body such that the second longitudinal axis is substantially parallel to the plane of the door and substantially perpendicular to the second movement axis. The first pin connects the deadbolt and first tailpiece so as to permit the deadbolt and first tailpiece to pivot with respect to each other about the first longitudinal axis, and the second pin connects the latch and second tailpiece so as to permit the latch and second tailpiece to pivot with respect to each other about the second longitudinal axis. 
     In some embodiments, the first tailpiece and first pin are integral. In some embodiments, the deadbolt comprises a cylindrical hole to receive the first pin. In some embodiments, the deadbolt comprises a slot formed in the portion of the deadbolt through which the cylindrical hole passes, and the slot is positioned in a plane that is substantially perpendicular to a central axis of the cylindrical hole. In some embodiments, the first pin comprises a notch positioned to correspond to the slot when the first pin is disposed in the cylindrical hole, and the assembly further comprises a clip securable to the notch for hindering removal of the first pin from the cylindrical hole. In some embodiments, the first tailpiece comprises a curved surface adjacent to the first pin to accommodate pivoting of the first tailpiece within the body. In some embodiments, the latch comprises a cavity at least partially shaped as a sphere adapted to receive an end of the tailpiece comprising a curved surface. 
     Exemplary embodiment(s) of the invention will now be described in greater detail in connection with the following drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1 a    is a perspective view of a mortise lock assembly according to a first embodiment of the present invention. 
         FIG. 1 b    is a perspective view of a strike plate for use with the assembly of  FIG. 1 . 
         FIG. 2 a    is a perspective view of the assembly of  FIG. 1   a.    
         FIG. 2 b    is a perspective view of the assembly of  FIG. 1   b.    
         FIG. 3  is a perspective view of a deadbolt assembly for use with the assembly of  FIG. 1 . 
         FIG. 4 a    is an exploded view of the deadbolt assembly of  FIG. 3 . 
         FIG. 4 b    is a top view of the tailpiece of  FIG. 3 . 
         FIG. 5 a    is a perspective view of a deadbolt according to a second embodiment of the present invention. 
         FIG. 5 b    is a perspective view of a tailpiece according to the second embodiment of the present invention. 
         FIG. 6 a    is a perspective view of a deadbolt according to a third embodiment of the present invention. 
         FIG. 6 b    is a perspective view of a pin according to the third embodiment of the present invention. 
         FIG. 6 c    is a perspective view of a tailpiece according to the third embodiment of the present invention. 
         FIG. 7  is a perspective view of a latch for use with the assembly of  FIG. 1 . 
         FIG. 8  is an exploded view of the latch of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of the invention will now be described with reference to the drawings.  FIG. 1 a    shows a mortise lock assembly  1 . In the embodiment shown, the assembly  1  is designed for installation in a mortise (or pocket) formed in a door. Mortises are most often formed using a mortise jig or other appropriate device. The assembly  1  comprises a lock body  2 , which serves as a kind of housing for the majority of the components of the assembly  1 . Sometimes, the lock body is referred to as a lock case. A faceplate  3  is secured to the lock body  2 . The faceplate  3  closes the side of the lock body  2  that is accessible from the side of the door and the faceplate  3  is the portion of the assembly  1  that is visible on the side of the door. 
     The faceplate  3  has openings for the deadbolt  4  and a latch  5 . The deadbolt  4  is shown in its extended position in  FIG. 1 a   , in which, if the assembly  1  were installed in a door, the deadbolt  4  would protrude through an opening in the strike plate to lock the door.  FIG. 1 b    shows an exemplary strike plate  6 . The strike plate  6  is typically installed on the inside surface of the doorframe. The strike plate  6  has an opening  7  for receiving the deadbolt  4  and an opening  8  for receiving the latch  5 . Although not shown in the figures, corresponding holes are cut in the doorframe to accommodate the deadbolt  4  and latch  5  when the door is closed and locked. 
     The lock body  2  also includes a circular opening or cylinder port  9  for accommodating a lock cylinder (not shown). As is known in the art, the lock cylinder interacts with the deadbolt  4  to move it between the extended position shown in  FIG. 1 a    and a retracted position. Typically, the deadbolt lock cylinder requires use of a key on at least one side of the door to turn the lock. (In many embodiments, both sides of the lock cylinder require use of a key to turn the lock cylinder). 
     The lock body  2  also includes a follower hole  13 , which is adapted to accommodate a spindle (not shown). The spindle connects a follower (shown in  FIGS. 2 a  and 2 b   ) to a door handle (not shown). When the door handle is turned, the spindle rotates the follower, which imparts lateral movement to the latch  5 . The latch  5  can be moved between an extended position (as shown in  FIG. 1 a   ) and a retracted position. 
       FIG. 2 a    is a view of the assembly  1  showing the inside of the lock body  2 . A deadbolt cam  10  is mounted adjacent to the cylinder port  9 . The deadbolt cam  10  interacts with the lock cylinder (not shown) to impart the rotational movement of the cylinder to the deadbolt  4 . The deadbolt  4  is connected to a tailpiece  11 . The tailpiece  11  has protrusions  12  against which the cam  10  bears to impart the movement of the turning lock cylinder. 
     The follower  14  interacts with a spindle (not shown) to impart the rotational movement the spindle to the latch  5 . The latch  5  has a tailpiece  15  attached to it and that is acted upon by the follower  14 . In some embodiments, a spring  16  is included around the tailpiece  15  of the latch  5  to bias the latch in an extended position. 
       FIG. 2 a    shows the deadbolt  4  and latch  5  in their extended positions.  FIG. 2 b    shows the interior of assembly  1  when the deadbolt  4  and latch  5  have been moved into their retracted positions. As shown, the cam  10  has moved the tailpiece  11 , and accordingly, the deadbolt  4  to the left in the figure. The deadbolt is moved along a movement axis  100  (shown in  FIGS. 2 a  and 2 b   ) by the movement of the lock and the cam. The axis  100  is in the plane of the door in which the mortise lock  1  is installed. Likewise, the follower  14  has moved the tailpiece  15  and the latch  5  to the left in the figure. The latch moves along a movement axis  120 . In their retracted positions, the deadbolt  4  and latch  5  are almost entirely within the lock body  2  such that, were the mortise lock installed in a door, the door could be freely opened and closed. 
     In prior art mortise lock assemblies, the deadbolt and its tailpiece and the latch and its tailpiece are fixed with respect to one another. In some instances, the bolt and tailpiece are integral, having been formed using a metal casting, forging, or milling process. In other instances, the bolt and tailpiece are formed separately and then fixedly joined by welding or using permanent fasteners. As described above, such prior art assemblies have proven to have a limited resistance to brute force attempts to break the lock. In many such prior art assemblies, when the bolt is in the extended position in order to secure and/or lock a door, an application of force can cause the rigidly connected bolt and tailpiece to break. In many cases, the assembly will fracture at a point of the tailpiece near to where the tailpiece meets the bolt. In many assemblies, this area is the weakest point once the bolt is extended between the door and the door frame in the extended position. Once the bolt assembly has been fractured, the door will either swing open or minor further manipulation will cause the bolt to fail completely. 
     According to the present invention, however, the bolt and tailpiece are joined to each other in a pivotable relationship. As shown in  FIGS. 2 a  and 2 b   , the deadbolt  4  and the tailpiece  11  are joined via a pin  21  and the latch  5  and tailpiece  15  are joined by a pin  17 . In this arrangement, the deadbolt is permitted to pivot relative to the tailpiece when subjected to a forceful impact. The deflection caused by such an impact will cause the deadbolt to pivot relative to the tailpiece instead of the tailpiece fracturing and the lock failing. 
     In the embodiment shown in  FIGS. 2 a  and 2 b   , both the deadbolt assembly and the latch assembly are pivotable. In other embodiments, however, a lock assembly is provided in which the deadbolt assembly is pivotable while the latch assembly is not. In still other embodiments, the latch assembly is pivotable while the deadbolt assembly is not. 
       FIGS. 3, 4   a , and  4   b  show additional details of a deadbolt assembly  20  according to a first embodiment of the present invention. The tailpiece  11  includes a pin  21 , which, in the embodiment shown, is in the form of a cylindrical rod. In this embodiment, the pin  21  is integral with the rest of the tailpiece  11 . The tailpiece  11  is formed by any suitable metal forming process, including casting, forging, etc. The deadbolt  4  includes a hole  22  adapted to receive the pin  21 . In the embodiment shown, the hole is cylindrical in shape. 
     The pin  21 , in this embodiment, includes a notch  24  that is adapted to receive a clip  25 . The clip  25  is used to retain the pin  21  in the hole  22  formed in the deadbolt  4 . To accommodate the clip  25 , the deadbolt  4  has a slot  23 . Once the tailpiece  11  has been attached to the deadbolt  4  by insertion of the pin  21  into the hole  22 , the clip  25  is snapped into place on the notch  24 . The clip  25  fits within the slot  23  and prevents the pin  21  from being removed from the hole  22 . In the embodiment shown, the slot  23  is formed generally in a plane that is substantially perpendicular to the central axis of the cylindrical hole  22 . 
     Once the deadbolt assembly  20  assembled, the deadbolt  4  and the tailpiece  11  are able to pivot relative to one another about the longitudinal axis of the pin  21 . This axis is shown in  FIG. 3  as axis  101 . When the assembly  20  is installed in the mortise lock assembly  1  in a door, the axis  101  is generally parallel to the plane of the door, but is generally perpendicular to the movement axis  100  of the deadbolt  4  along which the deadbolt  4  moves between the extended and retracted positions. The deadbolt  4  and tailpiece  11 , therefore, pivot relative to one another in the directions indicated by arrows  110  and  111 . 
     In the embodiments shown, both the pin and the corresponding hole are generally cylindrical to permit rotation of the parts joined by the pin and hole. In other embodiments, however, the hole and/or pin have different shapes. The shapes can be any that permit pivoting of the tailpiece relative to the deadbolt. 
     The tailpiece  11  shown in  FIG. 4 b    includes a curved portion  26 . In this embodiment, the curved portion  26  is located near the pin  21 , which is integral with the tailpiece  11 . In this embodiment, the hole  22  in the deadbolt  4  is offset from the center of the deadbolt (as defined, for example, by the movement axis  100 ). Because of this, one side of the tailpiece  11  is closer to the side of the deadbolt than the other side when the two components are connected. The curved surface  26  is formed on the tailpiece  11  to provide additional clearance for the tailpiece to rotate relative to the deadbolt within the lock body in which the assembly is installed. In the embodiment shown in  FIGS. 3, 4   a , and  4   b , the curved surface  26  is formed on the side of the tailpiece  11  that is closest to the side of the deadbolt as a result of the off-center hole  22 . In other embodiments, the tailpiece  11  includes curved surfaces on both sides to better accommodate pivoting of the tailpiece. In still other embodiments, the deadbolt  4  includes one or more curved surfaces to provide additional rotation or pivoting clearance. In other embodiments, both the deadbolt and the tailpiece include such curved surfaces. 
       FIGS. 5 a  and 5 b    show a second embodiment of a deadbolt assembly according to the present invention. In this embodiment, the deadbolt  34  has a pin  51 , and these components are integral with each other. Accordingly, the tailpiece  41  shown in  FIG. 5 b    has a cylindrical portion  56  with a hole  52  sized to receive the pin  51 . The cylindrical portion  56  includes a slot  53  to accommodate a clip. Accordingly, the pin  51  has a notch  54  to receiving the retaining clip similar to the first embodiment described above. As in the embodiment of  FIGS. 3, 4   a , and  4   b , the deadbolt assembly shown in  FIGS. 5 a  and 5 b   , when assembled, permits the deadbolt  34  and the tailpiece  41  to rotate with respect to one another about the axis  102 . Axis  102  is shown in both  FIGS. 5 a  and 5 b    for reference. As in other embodiments described herein, the axis  102  is oriented substantially parallel to the plane of the door and substantially perpendicular to the movement axis of the deadbolt when the deadbolt assembly is installed in a mortise lock assembly that is installed in a door. 
       FIGS. 6 a , 6 b , and 6 c    show a third embodiment of a deadbolt assembly according to the present invention. In this embodiment, both the deadbolt  64  and the tailpiece  71  have holes  82   a  and  82   b  for receiving a pin  81 . The pin  81  is, in this embodiment, a separate component from both the deadbolt  64  and the tailpiece  71 . In order for this embodiment to function reliably, two retaining clips  55   a  and  55   b  are required. The pin  81  has two notches  84   a  and  84   b  for receiving the retaining clips. The deadbolt  64  has a slot  83   a  for accommodating one of the clips and the tailpiece  71  has a slot  83   b  for accommodating the other of the clips. The slots  83  and clips  84  cooperate to hold the components of the deadbolt assembly shown in  FIGS. 6 a , 6 b , and 6 c    together. As in the previously described embodiments, the deadbolt  64  and tailpiece  71  will, when assembled pivot relative to one another about the axis  103 . When the deadbolt assembly is installed in a mortise lock assembly and installed in a door, the axis  103  is oriented substantially parallel to the plane of the door and substantially perpendicular to the axis along which the deadbolt moves when moving between an extended position and a retracted position. 
     The deadbolt assemblies of  FIGS. 3-6   c  are adapted for use with a lock assembly such as the one shown in  FIGS. 1-2   b . In some embodiments, the deadbolt assemblies are sold included with a complete lock assembly for installation in a door. In other embodiments, the deadbolt assemblies are provided separately from a lock assembly (as an aftermarket upgrade, for example) and can be installed in a lock assembly that is compatible with the deadbolt assembly. 
       FIG. 7  shows an exemplary embodiment of a pivotable latch assembly according to the present invention. The latch  5  is connected to the tailpiece  15  such that the latch and tailpiece can pivot relative to one another. They pivot about the axis  121 , which is positioned generally within the plane of the door in which the lock in which the latch assembly is installed. The axis  121  is also substantially perpendicular to the movement axis  120  along which the latch  5  moves when it is extended and retracted. The latch assembly also includes an endpiece  30  that is connected to the second end of the tailpiece  15 , and which interacts directly with the follower component of the lock assembly. 
       FIG. 8  shows an exploded view of the latch assembly of  FIG. 7 . The latch  5  has a cavity  18 , which is adapted to receive an end of the tailpiece  15 . The cavity  18  has the shape of at least part of a sphere, as does the end of the tailpiece  15 . In other embodiments, the cavity  18  and curved end of the tailpiece  15  have shapes other than that of a sphere, such as, for example, a cylindrical shape. The latch  5  and the tailpiece  15  both have holes  19   a  and  19   b , respectively, for receiving the pin  17 . As in the embodiments of the deadbolt assembly discussed above, the pin  17  is retained in the holes  19   a  and  19   b.    
     The pivotable nature of the bolt assemblies according to embodiments of the present invention enable locks in which the assemblies are installed to better absorb impacts intended to force the door open. Instead of fracturing at a point roughly between the tailpiece and bolt, the tailpiece and bolt will pivot relative to one another. The pivoting permits the bolt and tailpiece to “flex” in response to a forceful impact, and remain in a secure, locked condition throughout the impact. 
     Although the invention has been described with reference to particular embodiments and arrangements of parts, features and the like, these are not intended to exhaust all possible embodiments, arrangements, or features, and indeed many other modifications and variations will be ascertainable to those of skill in the art.