Patent Publication Number: US-2017362856-A1

Title: Strike plate with bolt sensing feature

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Ser. No. 62/350,774 filed Jun. 16, 2016 for a “Strike Plate with Bolt Sensing Feature,” which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to sensors for doors; in particular, this disclosure relates to sensors for detecting whether a door is fully latched. 
     BACKGROUND AND SUMMARY 
     Security systems are in widespread use in residential and commercial markets. These devices control ingress through doors to secured areas, such as a building or other secured space, by requiring certain authorized credentials. Existing security systems may include a sensor for determining whether a door is open or closed. In various embodiments of such systems, such a sensor may be located within the electronic latch mechanism in the door to determine if the bolt of the latch mechanism is retracted or extended. However, existing sensors are not able to provide exact location information regarding the bolt to determine whether the bolt is secured within a strike box of the door frame to ensure the door is closed. Further, existing sensors cannot determine whether a door is merely slightly ajar with the bolt extended or closed with the bolt secured within the strike box. Moreover, installation of existing sensors can be time consuming and aesthetically unpleasing. As one example, installers may be forced to separately install a magnet to a door and a magnetic sensor to molding surrounding the door (or vice versa) to determine orientation of the door to the door frame. Although such sensors are available in different colors to try to blend in with the door and molding colors, it can still have an unsightly appearance. 
     According to one aspect, this disclosure provides a sensor assembly that includes a sensor located within an opening formed in a strike box of the strike assembly. The sensor, which could be an optical, mechanical, continuity, inductive, ultrasonic, and/or mechanical sensor, is configured to detect whether the bolt of the bolt assembly is encompassed by the strike box. The sensor assembly is configured to interact with a surface of the bolt when the bolt is located within the opening. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The detailed description makes references to the accompanying figures in which: 
         FIG. 1  is a side view of a latch assembly in accordance with an embodiment of the present invention to be installed in a door and doorjamb; 
         FIG. 2  is a cross-sectional view of a lock assembly in accordance with an embodiment of the present disclosure, illustrating the latch assembly of  FIG. 1  installed in a door and a doorjamb; and 
         FIGS. 3-17  are cross-sectional views of various embodiments of a sensor assembly to be used with the latch assembly of  FIG. 1 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principals and functions of the invention. The exemplification set out herein illustrates embodiments of the invention, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION 
     While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure. Those of ordinary skill may recognize that other elements and/or operations may be desirable and/or necessary to implement the devices, systems, and methods described herein. Because such elements and operations are well known in the art, and because they do not facilitate a better understanding of the present disclosure, a discussion of such elements and operations may not be provided herein. 
     In the drawings, some structural features may be shown in specific arrangements and/or orderings. However, it should be appreciated that such specific arrangements and/or orderings may not be required. Rather, in some embodiments, such features may be arranged in a different manner and/or order than shown in the illustrative figures. Additionally, the inclusion of a structural or method feature in a particular figure is not meant to imply that such feature is required in all embodiments and, in some embodiments, may not be included or may be combined with other features. 
       FIGS. 1 and 2  illustrate various views of a latch assembly  100  according to one embodiment of the disclosure. The term “latch assembly” is broadly intended to encompass a latch mechanism of any electronic, electro-mechanical, or mechanical lock assemblies that utilize a bolt that is movable between a locked engaged with a strike box (or strike plate) and an unlocked position outside of the strike box (or strike plate) via electronical and/or mechanical force. It should be appreciated, however, that the present disclosure applies to any type of lock assembly that utilizes a bolt received within a strike box (or strike plate) and is not restricted to the specific embodiments described herein. 
     As illustrated in  FIGS. 1 and 2 , in a typical lock assembly  200 , the lock assembly  200  may include an exterior assembly  112 , the latch assembly  100 , and an interior assembly  114 . Typically, the exterior assembly  112  is mounted on the outside of a door  110 , while the interior assembly  114  is mounted inside the door  110 . The latch assembly  100  is configured to be located between the exterior and interior assemblies  112  and  114  and may be partially mounted in a bore  108  formed in the door  110 . The term “outside” is broadly used to mean an area outside a door and “inside” is also broadly used to denote an area inside a door. With an exterior entry door, for example, the exterior assembly may be mounted outside a building, while the interior assembly may be mounted inside the building. With an interior door, the exterior assembly may be mounted inside a building, but outside a room secured by the lock assembly, while the interior assembly may be mounted in the secured room. 
     In illustrative embodiments, the latch assembly  100  is configured to be operated by the interior and/or exterior assemblies  112  and  114  to latch or unlatch the door from a surrounding door frame/jamb  116  to restrict or permit access through the door frame  116 . In various embodiments, for example, the interior assembly  114  includes an interior cover  144  that houses internal components (not shown) of the internal assembly  114  which interact with the latch assembly  100  to operate the latch assembly  100 . Alternatively, the exterior assembly  112  may include components (not shown) which interact with the latch assembly  100  to operate the latch assembly  100 . As another embodiment, both the internal and external assemblies  112  and  114  can be configured with components to operate the latch assembly  100 . 
     As illustrated in  FIG. 1 , the latch assembly  100  generally comprises a bolt assembly  102  and a strike assembly  104 . The bolt assembly  102  is disposed substantially in the core  108  in the door  110 , and may be actuated manually via the internal or external assemblies  112  and  114  by a mechanical lock assembly, or electronically using, for example, a keypad, to extend and retract a bolt  118  of the bolt assembly  102 . In illustrative embodiments, for example, a turnpiece  146  of the interior assembly  114  may be rotated by a user to manually extend and retract the bolt  118 . The strike assembly  104  is disposed substantially in a core  106  in the door frame  116  of the door and is configured to receive the bolt  118  of the bolt assembly  102  within a strike box  124  of the strike assembly  104  when the door  110  is aligned with the door frame  116 . By containing the bolt  118  within the strike box  124 , the door  110  may be blocked or prevented from moving out of alignment with the door frame  116 , effectively latching the door  110  in a closed position. 
     In illustrative embodiments, the bolt assembly  102  comprises the bolt  118 , a sleeve  120 , a base plate  122 , and a bolt-driving mechanism  126 . The bolt  118  may be connected to the sleeve  120  and the bolt-driving mechanism  126  such that the bolt-retracting mechanism  126  can operate to extend or retract the bolt  118  within the sleeve  120 . For example, the bolt  118  may be configured to move linearly in and out of the sleeve  120  of the bolt assembly  102  along an extension axis  130  when the bolt-driving mechanism  126  is actuated (via the interior or exterior assemblies  112  and  114 , for example) to retract the bolt  118 . Various forms of bolt-retracting mechanisms are known in the art and considered within the scope of this disclosure. The sleeve  120  may be fixedly coupled to the base plate  122  to permit the bolt assembly  102  to be secured to the door  110 . For example, as is typical, the bolt assembly  102  may be located within the core  108  of the door  110  and further attached to at least a connecting edge  138  of the door  110  that extends between an exterior edge  140  ( FIG. 2 ) of the door  110  and an interior edge  142  ( FIG. 2 ) of the door  110 . The base plate  122  may be secured to be flush against the connecting edge  138  of the door  110  (via, for example, connecting screws  148 ) so that the sleeve  120  and bolt-retracting mechanism  126  are contained within the core  108  of the door  110 . 
     The bolt  118  may be configured of various dimensions that can be received within the strike box  124 . In illustrative embodiments, the bolt  118  could generally be rectangular in cross-section and includes at least a first end  132 , a first side  150 , a second side  152 , a top surface  154 , and a bottom surface  156 . When the bolt  118  is retracted within the sleeve  120 , the first end  132  of the bolt  118  is generally flush with the base plate  122 . When the bolt  118  is extended, the bolt  118  protrudes through an edge bore  134  in the door  110  into the strike box  124 , which is positioned in the jamb  116  adjacent the door  110 , in order to secure the door  110  to the jamb  116 . 
     As illustrated in  FIGS. 1 and 2 , the strike assembly  104  may comprise the strike box  124 , an opening  136  formed by the strike box  124 , and a base plate  158 . The strike box  124  may be fixedly connected to the base plate  158 , and the base plate  158  is formed to include an aperture  162  that permits access to the opening  136  of the strike box  124  form an exterior of the strike assembly  104 . As is typical, the strike assembly  104  is attached to the jamb  116  using fasteners  160  that extend through the base plate  158  so that the base plate  158  is flush with a surface  164  of the jamb  116 . When the base plate  158  is connected to the jamb  116 , the strike box  124  is configured to be contained within the core  106  formed in the jamb  116 . 
     The strike box  124  may be configured of various dimensions such that the opening  136  can receive the bolt  118  of the bolt assembly  102 . In illustrative embodiments, the strike box  124  is generally rectangular in cross-section and includes a back panel  166 , a first side panel  168 , a second side panel  170 , a top panel  172 , and a bottom panel  174 , and is formed to include an aperture  176  that is positioned opposite the back panel  166  and configured to align with the aperture  162  of the base plate  158  to permit access to the opening  136  of the strike box  124 . The opening  136  is defined by the connection of the back panel  166 , first side panel  168 , second side panel  170 , top panel  172  and bottom panel  174 . Under desired conditions, when the bolt  118  is extended into the strike box  124 , the bolt  118  is surrounded by the panels  166 ,  168 ,  170 ,  172  and  174 , and at least the first and second side panels  168  and  170  block movement of the bolt  118  out of the strike box  124  in order to secure the door  110  to the jamb  116 . In various embodiments, as illustrated in  FIGS. 3-17 , the top surface  154  of the bolt  118  may be slightly spaced apart from the top panel  172  of the strike box, and the bottom surface  156  of the bolt  118  may be slightly spaced apart from the bottom panel  174  of the strike box  124 , when the bolt  118  is received within the opening  136  of the strike box  124 . Similarly, the back panel  166  of strike box  124  may be slightly spaced apart from the first end  132  of the bolt  118  when the bolt  118  is received within the opening  136 . 
     In illustrative embodiments, the latch assembly  100  includes a sensor assembly  180  that is configured to detect whether the bolt  118  is located in the opening  136  of the strike box  124  a sufficient distance as to securely latch the door  110  to the jamb  116  in a closed position. In various embodiments, the sensor assembly  180  may be at least partially coupled to the strike assembly  104  to interact with the bolt  118  as it is received within the opening  136 . The sensor assembly  180  may alternatively be coupled to another part of the latch assembly  100  to detect if the bolt  118  has entered the opening  136  of the strike box  124 . 
     Various embodiments of the sensor assembly  180  will now be described herein. The various embodiments are provided to illustrate how the sensor assembly  180  can work in conjunction with the strike assembly  104  and/or bolt  118  to detect that the bolt  118  is adequately contained within the strike box  124  of the strike assembly  104  or not, and are not intended to limit the scope of the sensor assembly  180 . It is within the scope of this disclosure for the determination of the amount of the bolt  118  that is required to be considered adequately secured may be performed during set up or installation, or may be mechanically configured by other factors. It is also within the scope of this disclosure that the sensor assembly  180  may be configured to have multiple sensing components that can determine the depth of the bolt  118  within the strike box  104 , and also determine travel direction of the bolt  118 . Other measurements and determinable characteristics of the bolt  118  as it travels into the strike box  104  will be understood to one of ordinary skill in the art. 
     In a first illustrative embodiment of the sensor assembly  180 , an optical sensor  210  may be located along an inside surface  182  of the back panel  166  of the strike box  124 , as illustrated in  FIG. 3 . The optical sensor  210  includes a transmission (TX) portion  212  and a receiver (RX) portion  214 , with the TX portion  212  configured to transmit or send an optical signal  215  along a TX axis  216  that is substantially parallel with the extension axis  130  of the bolt  118 , the TX axis  216  configured to intersect a portion of the first end  132  of the bolt  118  when the bolt  118  enters the strike box  124 . The signal  215  is configured to be reflected off of the first end  132  of the bolt  118  when the bolt  118  is received within the strike box  124  such that the signal will reflect off of the bolt  118  and back toward the back panel  166  of the strike box  124  along a RX axis  218 . In such an embodiment, the RX portion  214  is configured to be aligned with the RX axis  218  to receive the signal  215  after it has bounced off of the first end  132  of the bolt  118 . The RX portion  214  of the optical sensor  210  is configured to detect the strength of the reflection of the signal  215  after it has bounced off of the first end  132 . When the bolt  118  is located at a predetermined distance from the sensor  210  that corresponds with the bolt  118  being secured within the strike box  124 , the signal  215  will have a determinable reflection strength. The sensor assembly  180  can accordingly detect when the bolt  118  is located within the strike box  124  by analyzing the reflection strength of the signal  215  via the RX portion  214  of the sensor. If the bolt  118  is not located within the strike box  124  or located within a predetermined distance of the TX portion  212  that can receive/deflect the signal  215 , then the signal  215  will not be returned to the RX portion  214  and the sensor assembly  180  will then indicate that the bolt  118  is not located within the strike box  124 , i.e., the door  110  is not completely latched closed. 
     In a second illustrative embodiment of the sensor assembly  180 , the optical sensor  210  may operate in a similar manner as the first illustrative embodiment and as illustrated in  FIG. 3 , except the sensor assembly  180  has the ability to track the time from transmission of the signal  215  by the TX portion  212  to receipt of the signal  215  by the RX portion  214 . In this manner, when the bolt  118  is located at a predetermined distance from the sensor  210  that corresponds with the bolt  118  being secured within the strike box  124 , there will be a predetermined length of time for the signal to travel from the TX portion  212  to the RX portion  214 . The sensor assembly  180  can accordingly detect when the bolt  118  is located within the strike box  124  by analyzing whether the time between sending signal  215  from the TX portion  212  to the RX portion  214  meets the predetermined length of time. If the bolt  118  is not located within the strike box  124  or located within a predetermined distance of the TX portion  212  that can receive/deflect the signal  215 , then the signal  215  will not be returned to the RX portion  214  and there will be no end time registered by the RX portion  214 . Accordingly, the sensor assembly  180  will then indicate that the bolt  118  is not located within the strike box  124 , i.e., the door  110  is not completely latched closed. 
     In a third illustrative embodiment of the sensor assembly  180 , the optical sensor  210  may operate in a similar manner as the first embodiment, except that the sensor assembly  180  may be located along an inside surface  184  of the top panel  172 , as illustrated in  FIG. 4 . The TX portion  212  of the optical sensor  210  is configured to transmit or send the optical signal  215  along a TX axis  217  that is substantially perpendicular to the extension axis  130  of the bolt  118 , the TX axis  217  configured to intersect the top surface  154  of the bolt  118  when the bolt  118  extends a predetermined distance D into the strike box  124  from the surface  164  of the jamb  116 , wherein the distance D can represent the amount of distance that the bolt  118  must travel past the surface  164  and into the opening  136  of the strike box  124  to be securely retained within the strike box  124 . The signal  215  is configured to be reflected off of the top surface  154  of the bolt  118  when the bolt  118  is received within the strike box  124  such that the signal will reflect off of the bolt  118  and back toward the top panel  172  of the strike box  124  along an RX axis  219 . In such an embodiment, the RX portion  214  is configured to be aligned with the RX axis  219  to receive the signal  215  after it has bounced off of the top surface  154  of the bolt  118 . If the sensor assembly  180  detects the bolt  118  is located within the strike box  124  by analyzing whether the RX portion  214  has received the signal  215 , then the sensor assembly  180  can indicate that the door  110  is adequately latched closed. In an alternative to this embodiment, an optical sensor  210   a  may be alternatively positioned along an inside surface  186  of the bottom panel  174  of the strike box  124  that can send a signal  215  to deflect off the bottom surface  156  of the bolt  118 . Alternatively, the sensor assembly  180  may include both a first optical sensor  210  and a second optical sensor  210   a.    
     In a fourth illustrative embodiment of the sensor assembly  180 , the optical sensor  210  may operate in a similar manner as the third illustrative embodiment and as illustrated in  FIG. 4 , except the sensor assembly  180  has the ability to track the time from transmission of the signal  215  by the TX portion  212  to receipt of the signal  215  by the RX portion  214 , similar to the second illustrative embodiment. In this manner, when the bolt  118  is located in the strike box  124  and intersects TX axis  216 , there will be a predetermined length of time for the signal to travel from the TX portion  212  to the RX portion  214 . The sensor assembly  180  can accordingly detect when the bolt  118  is secured within the strike box  124  by analyzing whether the time between sending signal  215  from the TX portion  212  to the RX portion  214  the reflection strength of the signal  215  via the RX portion  214  of the sensor. If the bolt  118  is not secured within the strike box  124  or located within a predetermined distance of the TX portion  212  that can receive/deflect the signal  215 , then the signal  215  will not be returned to the RX portion  214  and there will be no end time registered by the RX portion  214 . 
     In a fifth illustrative embodiment of the sensor assembly  180 , an optical sensor  220  may be located along both an inside surface  184  of the top panel  172  and an inside surface  186  of the bottom panel  174  of the strike box  124 , as illustrated in  FIG. 5 . The optical sensor  220  includes a transmission (TX) portion  222  and a receiver (RX) portion  224 , with the TX portion  222  configured to transmit or send an optical signal  225  along a beam axis  226  that intersects the RX portion  224 . The TX portion  222  may be configured to transmit the optical signal  225  continuously, or a predetermined time intervals, to the RX portion  224 . As illustrated in  FIG. 5 , the beam axis  226  may be substantially perpendicular to the extension axis  130  of the bolt  118 , although other alignments of the beam axis  226  and the extension axis  130  are envisioned herein. The beam axis  226  is configured to be at least a predetermined distance D from the surface  164  of the jamb  116 , wherein the distance D can represent the amount of distance that the bolt  118  must travel past the surface  164  and into the opening  136  of the strike box  124  to be securely retained within the strike box  124 . As the bolt  118  is received within the strike box  124 , the top surface  154  and/or the bottom surface  156  of the bolt  118  will intersect the beam axis  226 , breaking the signal  225  from the TX portion  222  to the RX portion  224 . Accordingly, when the RX portion  224  of the optical sensor  210  fails to detect the signal  225 , the sensor assembly  180  can identify that the bolt  118  is located within the strike box  124 , i.e., the door is latched closed. Otherwise, the sensor assembly  180  detects that the door is not fully latched closed. 
     In a sixth illustrative embodiment of the sensor assembly  180 , a mechanical sensor  230  may be located along an inside surface  182  of the back panel  166  of the strike box  124 , as illustrated in  FIG. 6 . The mechanical sensor  230  may be comprised of a movable switch  232 , a biasing member  234 , and an optional base  236  upon which the switch  232  is hinged or pivoted for movement. The mechanical sensor  230  is mounted upon the back panel  166  in such a way that the switch  232  extends within the opening  136  such that a portion (such as an end  233 ) of the switch  232  intersects with the extension axis  130  of the bolt  118 . The switch  232  is biased away from the back panel  166  by the biasing member  234  toward the aperture  162  of the strike box  124 . The switch  232  is configured to be pushed toward the back panel  166  when the first end  132  of the bolt  118  abuts against the switch  232  as the bolt enters the strike box  124 . The switch  232  may be located along an actuation axis  238  that is generally perpendicular to the extension axis  130 , and the actuation axis  238  may be located a predetermined distance D from the surface  164  of the jamb  116  that corresponds with the bolt  118  being secured within the strike box  124 . When the first end  132  of the bolt  118  is located at the predetermined distance D from the surface  164 , it will biases the switch  232  toward the back panel  166  against the biasing member  234 . The sensor assembly  180  then detects that the bolt  118  is located within the strike box  124  and the door  110  is latched. If the bolt  118  is not located within the strike box  124  or located within the predetermined distance D of the switch  232  to bias the switch  232  toward the back panel  166 , then the sensor assembly  180  will then indicate that the bolt  118  is not located within the strike box  124 , i.e., the door  110  is not completely latched closed. 
     In a seventh illustrative embodiment of the sensor assembly  180 , the sensor assembly  180  may operate in a similar manner as the sixth embodiment, except that the sensor assembly  180  may be located along an inside surface  184  of the top panel  172 , as illustrated in  FIG. 7 . The switch  232  is biased away from the top panel  172  by the biasing member  234  toward the bottom panel  174  of the strike box  124 . The mechanical sensor  230  is mounted upon the back panel  166  in such a way that the switch  232  extends within the opening  136  such that the end  233  of the switch  232  is positioned along an intersection axis  239  of the top surface  154  bolt  118  when switch  232  is in a natural state that is biased way from the top panel  172  by the biasing member  234 . The intersection axis  239  is generally parallel to the extension axis  130 . The end  233  of the switch  232  is also positioned a predetermined distance D from the surface  164  of the jamb  116  that corresponds with the bolt  118  being secured within the strike box  124 . When the bolt  118  is moved within the strike box  124  the predetermined distance D, the top surface  154  of the bolt  118  will abut against the end  233  of the switch  232  and move the switch upward toward the top panel  172 . The sensor assembly  180  then detects that the bolt  118  is located within the strike box  124  and the door  110  is latched. If the bolt  118  is not located within the strike box  124  or located within the predetermined distance D of the switch  232  to bias the switch  232  toward the top panel  172 , then the sensor assembly  180  will then indicate that the bolt  118  is not located within the strike box  124 , i.e., the door  110  is not completely latched closed. As an alternative or in conjunction with this illustrative embodiment, the sensor assembly  180  may comprise a mechanical sensor positioned along the inside surface  186  of the bottom panel  174  of the strike box  124  in order to intersect the bottom surface  156  of the bolt  118 . 
     In an eighth illustrative embodiment of the sensor assembly  180 , a capacitive sensor  240  may be located along an inside surface  182  of the back panel  166  of the strike box  124 , as illustrated in  FIG. 8 . The capacitive sensor  240  includes one or more capacitive sensor elements  242  that are configured to emit an electrical field  244  within the opening  136  of the strike box  124 . The sensor assembly  180  is configured to detect changes in the electrical filed  244  generated by the capacitive sensor  240 . The capacitive sensor element  242  is located to be substantially aligned with the extension axis  130  of the bolt  118  when the bolt  118  enters the strike box  124 . As the first end  132  of the bolt  118  extends within the opening  136 , it will replace the dielectric constant of air, as is generally known. The capacitive sensor element  242  can be configured to create an electrical field  244  that generally extends to an actuation axis  246 , the actuation axis generally extending a predetermined distance D from the surface  164  of the jamb  116  that corresponds with the bolt  118  being secured within the strike box  124 . When the bolt  118  is moved within the strike box  124  the predetermined distance D, the electrical field  244  is changed and the capacitive sensor  240  can detect the change, for instance, an increase in the capacitance sensed. When a pre-determined capacitive threshold is reached within the electrical field  244 , the sensor assembly  180  will register that the bolt  118  is secured within the strike box  124 . If the bolt  118  is not located within the strike box  124  or located within a predetermined distance D to alter the electrical field  244 , then the sensor assembly  180  will then indicate that the bolt  118  is not located within the strike box  124 , i.e., the door  110  is not completely latched closed. 
     In a ninth illustrative embodiment of the sensor assembly  180 , the sensor assembly  180  may operate in a similar manner as the seventh embodiment, except that the sensor assembly  180  may be located along an inside surface  188  of the first side panel  168  of the strike box  124 , as illustrated in  FIG. 9 . The capacitive sensor  240  includes one or more capacitive sensor elements  242  that are configured to emit an electrical field  244  within the opening  136  of the strike box  124 . The capacitive sensor elements  242  are aligned along a measurement plane/axis  248  that is generally perpendicular to the extension axis  130  of the bolt  118  when it is received within the strike box  124 . As in the previous embodiment, the bolt  118  will saturate or change the electrical field  244  as it comes within a predetermined distance of the field  244 , and the capacitive sensor element  242  generating the electrical field  244  will be able to detect such change. In various embodiments, the capacitive sensor elements  242  may be positioned to be a predetermined distance D from the surface  164  of the jamb  116  that corresponds with the bolt  118  being secured within the strike box  124 . Alternatively, the capacitive sensor elements  242  may be positioned along length of the first side panel  168  to detect as the bolt  118  is inserted into the opening  136 , and the sensor assembly  180  may have a pre-determined threshold of saturation across all of the capacitive sensor elements  242  (or a pre-determined order of saturating each of the individual sensor elements  242 ) that determines whether the bolt  118  is located sufficiently within the opening  136  of the strike box  124  to secure the bolt  118  and ensure the door  110  is latched sufficiently. It is further envisioned that the capacitive sensor  240  may be positioned along the second side panel  170 , the top panel  172 , or the bottom panel  174  of the strike box  124 , or multiple capacitive sensors  240  may be positioned on one or more of these panels, within the scope of this disclosure. 
     In a tenth illustrative embodiment of the sensor assembly  180 , an inductive sensor  250  may be located along an inside surface  182  of the back panel  166  of the strike box  124 , as illustrated in  FIG. 10 . The inductive sensor  250  includes one or more inductive coil elements  252  that are configured to emit an electrical field  254  within the opening  136  of the strike box  124 . The sensor assembly  180  is configured to detect the frequency in the electrical field  254  generated by the inductive sensor  250 . The inductive coil element  252  is located to be substantially aligned with the extension axis  130  of the bolt  118  when the bolt  118  enters the strike box  124 . As the first end  132  of the bolt  118  extends within the opening  136 , it will replace the dielectric constant of air, which, in turn will change the frequency measured by the inductive sensor  250 , as is generally known. The inductive coil element  252  can be configured to create an electrical field  254  that generally extends to an actuation axis  256 , the actuation axis  256  generally being perpendicular to the extension axis  130  and extending a predetermined distance D from the surface  164  of the jamb  116  that corresponds with the bolt  118  being secured within the strike box  124 . When the bolt  118  is moved within the strike box  124  the predetermined distance D, the electrical field  254  is changed and the inductive sensor  250  can detect the change in frequency. When a pre-determined frequency threshold is reached within the electrical field  254 , the sensor assembly  180  will register that the bolt  118  is secured within the strike box  124 . If the bolt  118  is not located within the strike box  124  or located within a predetermined distance D to alter the electrical field  254 , then the sensor assembly  180  will then indicate that the bolt  118  is not located within the strike box  124 , i.e., the door  110  is not completely latched closed. 
     In an eleventh illustrative embodiment of the sensor assembly  180 , the sensor assembly  180  may operate in a similar manner as the tenth embodiment, except that the sensor assembly  180  may be positioned around an exterior circumference  190  of the strike box  124 , as illustrated in  FIG. 11 . The exterior circumference  190  of the strike box  124  may be defined by the back panel  166 , first side panel  168 , second side panel  170 , top panel  172 , and bottom panel  174 . Specifically, the inductive sensor  250  may be configured such that the inductive coil element  252  is wrapped around an outside of the exterior circumference  190  of the strike box  124 , or the inductive coil element  252  may be wrapped around an inside of the exterior circumference  190  and contained within the opening  136 . The inductive coil element  252  is configured to create the electrical field  254  within the opening  136 , and the inductive sensor  250  is configured to measure the frequency of the electrical field  254 . As the first end  132  of the bolt  118  extends within the opening  136 , the bolt  118  will replace the dielectric constant of air, which, in turn will change the frequency measured by the inductive sensor  250 , as is generally known. An actuation axis  256  is perpendicular to the extension axis  130  of the bolt  118  and is defined by being a predetermined distance D from the surface  164  of the jamb  116  that corresponds with the bolt  118  being secured within the strike box  124 . When the bolt  118  is moved within the strike box  124  the predetermined distance D, the inductive sensor  250  registers the change in frequency in the electrical field  254 , the predetermined distance D corresponding with a when a pre-determined frequency threshold. If the pre-determined frequency threshold is reached within the electrical field  254 , the sensor assembly  180  will register that the bolt  118  is secured within the strike box  124 . Otherwise, the sensor assembly  180  will register that the door is not securely latched (e.g. closed). 
     As an alternative embodiment to the eleventh embodiment described above, the bolt  118  may include an optional RFID chip  292  that is in communication with the inductive sensor  250 . The RFID chip  292  within the bolt  118  may be configured to be activated when the bolt  118  reaches a predetermined distance within the electrical field  254  created by the inductive coil element  252 , as illustrated in  FIG. 11A . When the bolt  118  is moved within the strike box  124  a predetermined distance that actuates the permits the electrical field  254  to actuate the RFID chip  292 , and the RFID chip  292  will send a signal to the inductive sensor  250  that registers the bolt is securely retained within the strike box  124 . 
     In a twelfth illustrative embodiment of the sensor assembly  180 , an ultrasonic sensor  260  may be located along an inside surface  182  of the back panel  166  of the strike box  124 , as illustrated in  FIG. 12 . The ultrasonic sensor  260  includes a transmission (TX) portion  262  and a receiver (RX) portion  264 , with the TX portion  212  configured to transmit or send an ultrasonic signal  265  in a transmission field  266  that substantially intersects with the extension axis  130  of the bolt  118 . The transmission field  266  is configured to permit the ultrasonic signal  265  to interact with a portion of the first end  132  of the bolt  118  when the bolt  118  enters the strike box  124 . The signal  265  is configured to be reflected off of the first end  132  of the bolt  118  when the bolt  118  is received within the strike box  124  such that the signal  265  will reflect off of the bolt  118  and back toward the back panel  166  of the strike box  124  through the transmission field  266 . In such an embodiment, the RX portion  264  is configured to be aligned with the transmission field  266  to receive the signal  265  after it has bounced off of the first end  132  of the bolt  118 . The RX portion  264  of the ultrasonic sensor  260  is configured to detect the strength of the reflection of the signal  265  after it has bounced off of the first end  132 . When the bolt  118  is located at a predetermined distance from the sensor  260  that corresponds with the bolt  118  being secured within the strike box  124 , the signal  265  will have a determinable reflection strength. The sensor assembly  180  can accordingly detect when the bolt  118  is located within the strike box  124  by analyzing the reflection strength of the signal  265  via the RX portion  214  of the sensor  260 . If the bolt  118  is not located within the strike box  124  or located within a predetermined distance of the TX portion  262  that the bolt  118  can receive/deflect the signal  265 , then the signal  265  will not be returned to the RX portion  264  and the sensor assembly  180  will then indicate that the bolt  118  is not located within the strike box  124 , i.e., the door  110  is not completely latched closed. 
     In a thirteenth illustrative embodiment of the sensor assembly  180 , an ultrasonic sensor  260  may be located along both an inside surface  184  of the top panel  172  and an inside surface  186  of the bottom panel  174  of the strike box  124 , as illustrated in  FIG. 13 . The ultrasonic sensor  260  includes a transmission (TX) portion  262  and a receiver (RX) portion  264 , with the TX portion  262  configured to transmit or send an ultrasonic signal  265  along a beam axis  268  that intersects the RX portion  264 . The TX portion  262  may be configured to transmit the ultrasonic signal  265  continuously, or a predetermined time intervals, to the RX portion  264 , and the RX portion  264  is configured to detect a signal  265  from the TX portion  262  when there are no interruptions along the beam axis  268 . As illustrated in  FIG. 13 , the beam axis  268  may be substantially perpendicular to the extension axis  130  of the bolt  118 , although other alignments of the beam axis  268  and the extension axis  130  are envisioned herein. The beam axis  268  is configured to be at least a predetermined distance D from the surface  164  of the jamb  116 , wherein the distance D can represent the amount of distance that the bolt  118  must travel past the surface  164  and into the opening  136  of the strike box  124  to be securely retained within the strike box  124 . As the bolt  118  is received within the strike box  124 , the top surface  154  and/or the bottom surface  156  of the bolt  118  will intersect the beam axis  268 , breaking the signal  265  from the TX portion  262  to the RX portion  264 . Accordingly, when the RX portion  264  of the ultrasonic sensor  260  fails to detect the signal  265 , the sensor assembly  180  can identify that the bolt  118  is located within the strike box  124 , i.e., the door is latched closed. Otherwise, the sensor assembly  180  detects that the door is not fully latched closed. 
     In a fourteenth illustrative embodiment of the sensor assembly  180 , a continuity sensor  270  may be located along an inside surface  182  of the back panel  166  of the strike box  124 , as illustrated in  FIG. 14 . The continuity sensor  270  may be comprised of a first leaf spring  272  and a second leaf spring  274 , which each of the leaf springs  272  and  274  having a normal state (biased open or biased closed). The continuity sensor  270  is mounted upon the back panel  166  in such a way that the leaf springs  272  can extend within the opening  136  such that a portion (such as ends  273  and  275 ) of the leaf springs  272  and  274 , the leaf springs being aligned to be engaged by the bolt  118  (e.g. the first end  132  of the bolt  118 ) when the bolt  118  extends a predetermined distance D within the strike plate  124  and the leaf springs  272  and  274  are in their normal state. As the bolt reaches the first and/or second leaf springs  272  and/or  274 , the normal stage of the leaf springs  272  and  274  will be changed. The continuity sensor  270  is configured to detect a change in the state of the leaf springs  272  and  274 , and will register that the bolt has entered the strike box  124 . In various embodiments, the predetermined distance D is the distance between the first edge  132  of the bolt  118  and the surface  164  of the jamb  116  when the bolt  118  is securely retained within the strike box  124 . Accordingly, the continuity sensor  270  can indicate that the door is securely closed if the continuity sensor  270  is configured such that the leaf springs  272  and  274  cannot be changed out of their normal state unless the bolt  118  has reached or exceeded the predetermined distance D. 
     In a fifteenth illustrative embodiment of the sensor assembly  180 , a continuity sensor  280  may be located along both an inside surface  184  of the top panel  172  and an inside surface  186  of the bottom panel  174  of the strike box  124 , as illustrated in  FIG. 15 . The continuity sensor  280  may be comprised of a first moveable feature  282  and a second movable feature  284 . In various embodiments, the moveable features  282  and  284  are any components that can be moved by a bolt  118  when a bolt  118  comes into contact with the features  282  and  284 , and that such movement is capable of being detected by a sensor mechanism. For instance, the moveable features  282  and  284  may be comprised of brushes that extend into the opening  136  from the top panel  172  and bottom panel  174 , the brushes having free ends  283  and  285 , respectively, that may abut against the top surface  154  and bottom surface  156  of the bolt  118  and be deflected where such deflection can be sensed by the a sensor. Alternatively, each of the movable features  282  and  284  may be comprised of one or more leave springs biased into the opening  136  with free ends  283  and  285 . The ends  283  and  285  extend at least a distance X into the opening  136  such that the ends  283  and  285  will engage with the bolt  118  when the bolt  118  is secured within the strike box  124 . Other forms of moveable features are known in the art. As illustrated in  FIG. 15 , the movable features  282  and  284  are positioned along an actuation axis  286  that may be substantially perpendicular to the extension axis  130  of the bolt  118 , although other alignments of the actuation axis  286  and the extension axis  130  are envisioned herein. The actuation axis  286  is configured to be at least a predetermined distance D from the surface  164  of the jamb  116 , wherein the distance D can represent the amount of distance that the bolt  118  must travel past the surface  164  and into the opening  136  of the strike box  124  to be securely retained within the strike box  124 . When the bolt  118  engages with the movable features  282  and  284  within the opening  136 , the normal state of the movable features  282  and  284  will be changed and the sensor assembly  180  will register that the bolt has entered the strike box  124 . 
     In a sixteenth illustrative embodiment of the sensor assembly  180 , a magnet/hall sensor  290  may be located along an inside surface  182  of the back panel  166  of the strike box  124 , as illustrated in  FIG. 16 . The hall sensor  290  includes a hall-effect sensing mechanism  298  that measures the local magnetic field strength of the surrounding area  294  within the opening  136  of the strike box  124 . The sensor assembly  180  further includes a magnet or other similar magnet component  296  that is carried by the bolt  118  adjacent the first end  132  of the bolt  118 . In illustrative embodiments, the magnet  296  may be located inside the bolt  118 . As the bolt  118  travels into the opening  136  and the surrounding area  294  around the hall sensor  290 , the magnetic field strength is increased. The sensor  290  can be configured with a predetermined threshold magnetic field strength such that, if the threshold is reached, the sensor  290  will register that the bolt  118  is within the strike box  124  a predetermined distance. The predetermined distance can represent the amount of distance that the bolt  118  must travel past the surface  164  and into the opening  136  of the strike box  124  to be securely retained within the strike box  124 . When the hall sensor  290  registers this predetermined distance, the sensor assembly  180  will register that the bolt has entered and is retained within the strike box  124 . The amount of predetermined magnetic flux can optionally be calibrated during set-up to account for different door preparation and system configurations. 
     In a seventeenth illustrative embodiment of the sensor assembly  180 , the sensor assembly  180  may operate in a similar manner as the sixteenth embodiment, except that the sensor assembly  180  may be located along an inside surface  184  of the top panel  172 , as illustrated in  FIG. 17 . The magnet or other similar magnet component  296  that is carried by the bolt  118  may be positioned adjacent the first end  132  of the bolt  118  or adjacent the top surface  154  of the bolt  118 . In illustrative embodiments, the magnet  296  may be located inside the bolt  118 . As with the previous embodiment, the sensor assembly  180  includes a hall-effect sensor  290  that can detect and determine the strength of a magnetic field in a surrounding area  294 . Accordingly, the sensor assembly  180  can register if the bolt has entered the strike box  124 , and further if the bolt has traveled far enough into the strike box  124  to be securely retained within the strike box  124 . 
     A method of using the sensor assembly  180  will now be described. The sensor assembly  180  is coupled to or incorporated in a latch assembly  100  to determine whether a bolt assembly  102  of the latch assembly  100  is engaged with a strike assembly  104  of the latch assembly, and in particular, whether a bolt  118  of the bolt assembly  102  is securely retained within a strike box  124  of the strike assembly  104 . The bolt  118  may be positioned, in a first instance, outside of the strike box  124  such that a door  110  in which the bolt assembly  102  is retained is not securely latched. The sensor assembly  180  is at least partially coupled to or retained by the strike assembly  104  and operates to sense whether an interior cavity or opening  136  of the strike box  124  configured to receive the bolt  118  has an object (such as the bolt  118 ) retained therein. The sensor assembly  180  detects whether the bolt  118  is positioned within the strike box  124  by including at least one sensor retained by the strike box  124 . In a first step of the method, the bolt  118  is positioned outside of the strike box  124  and the sensor of the sensor assembly  180  detects that the opening  136  of the strike box  124  does not contain the bolt  118 . When the bolt  118  is moved into the opening  136  of the strike box  124 , the sensor of the strike box  124  detects a change within the opening  136  and indicates that the bolt  118  has been positioned therein. In various embodiments, the sensor of the strike box  124  can detect how far away an end surface  132  of the bolt  118  is positioned from a back panel  166  of the strike box  124 , and accordingly can detect whether the end surface  132  of the bolt  118  is adequately within the strike box  124  such that it is retained therein and will not exit the strike box  124  if a force is applied to the door  110  to which the bolt  118  is attached to disengage the door from its door jamb  116 . 
     EXAMPLES 
     Example 1 provides a sensor assembly for a lock assembly of a door. The sensor assembly includes a sensor located within an opening formed in a strike box of the lock assembly. The sensor is configured to detect whether a bolt of the lock assembly has entered the opening a sufficient distance so as to prevent removal of the bolt from the opening when an opening force is applied to the door. 
     In Example 2, the subject matter of Example 1 is further configured such that the sensor is an optical sensor that transmits an optical signal that interacts with the bolt when the bolt is within the opening. 
     In Example 3, the subject matter of Example 2 is further configured such that the optical sensor includes a transmission portion and a receiver portion. 
     In Example 4, the subject matter of Example 2 is further configured such that the sensor is located along a back panel of the strike box. 
     In Example 5, the subject matter of Example 4 is further configured such that the bolt is located within the opening, the optical signal is transmitted from the optical sensor, bounces off of an end of the bolt, and is transmitted back to the optical sensor. 
     In Example 6, the subject matter of Example 2 is further configured such that the sensor is located along a top panel of the strike box. 
     In Example 7, the subject matter of Example 1 is further configured such that the sensor assembly includes two or more optical sensors. 
     In Example 8, the subject matter of Example 1 is further configured such that the optical sensor transmits the optical signal along a transmission axis that is parallel to an extension axis upon which the bolt extends within the opening. 
     In Example 9, the subject matter of Example 1 is further configured such that the sensor is a mechanical sensor. 
     In Example 10, the subject matter of Example 9 is further configured such that the mechanical sensor comprises a moveable switch that is biased to an open position by a biasing member. 
     In Example 11, the subject matter of Example 10 is further configured such that the mechanical sensor is positioned along a back panel of the strike box, and wherein the moveable switch extends toward an opening of the strike box in the open position. 
     In Example 12, the subject matter of Example 11 is further configured such that the movable switch is positioned in the path of movement of the bolt as the bolt is moved along an extension axis into the opening such that the moveable switch is capable of being engaged by an end of the bolt. 
     In Example 13, the subject matter of Example 9 is further configured such that the mechanical sensor is positioned along a top pane of the strike box. 
     In Example 14, the subject matter of Example 1 is further configured such that the sensor is a capacitive sensor that emits an electrical field within the opening. 
     In Example 15, the subject matter of Example 14 is further configured such that the capacitive sensor includes a sensor element that detects changes in the electrical field. 
     In Example 16, the subject matter of Example 14 is further configured such that the electrical field extends at least to an actuation axis, the actuation axis defined by being a predetermined distance into the opening of the strike box from an aperture providing access to the opening. 
     In Example 17, the subject matter of Example 14 is further configured such that the sensor is located along a back panel of the strike box. 
     In Example 18, the subject matter of Example 14 is further configured such that the sensor is located along a side panel of the strike box. 
     In Example 19, the subject matter of Example 18 is further configured such that the sensor element includes a plurality of sensing elements that detect changes in the electrical field, the plurality of sensing elements positioned in a linear arrangement that is substantially parallel with an extension axis of the bolt as it extends within the opening. 
     In Example 20, the subject matter of Example 1 is further configured such that the sensor is an inductive sensor. 
     In Example 21, the subject matter of Example 20 is further configured such that the inductive sensor is located along a back panel of the strike box. 
     In Example 22, the subject matter of Example 1 is further configured such that the inductive sensor is located along an exterior circumference of the strike box. 
     In Example 23, the subject matter of Example 20 is further configured such that the sensor includes one or more inductive coil elements that emit an electrical field within the opening, the sensor configured to detect the frequency of the electrical field. 
     In Example 24, the subject matter of Example 23 is further configured such that the bolt is configured to change the dielectric constant of air within the opening. 
     In Example 25, the subject matter of Example 24 is further configured such that the dialectical constant of air within the opening will reach a predetermined level when the bolt is located the predetermined distance within the strike box. 
     In Example 26, the subject matter of Example 25 is further configured such that the predetermined distance corresponds with an actuation axis of the bolt, and the electrical field extends to at least the actuation axis. 
     In Example 27, the subject matter of Example 27 is further configured such that the sensor is an ultrasonic sensor. 
     In Example 28, the subject matter of Example 27 is further configured such that the sensor includes a transmission portion and a receiver portion. 
     In Example 29, the subject matter of Example 28 is further configured such that the transmission portion transmits an ultrasonic signal into a transmission field within the opening. 
     In Example 30, the subject matter of Example 29 is further configured such that the transmission field extends to at least an actuation axis of the bolt, wherein the actuation axis of located at the predetermined distance within the strike box. 
     In Example 31, the subject matter of Example 29 is further configured such that the sensor is located along a back panel of the strike box. 
     In Example 32, the subject matter of Example 31 is further configured such that the ultrasonic signal is transmitted along a transmission axis, the transmission axis being substantially parallel to an extension axis of the bolt. 
     In Example 33, the subject matter of Example 27 is further configured such that the sensor is located along top and bottom panels of the strike box. 
     In Example 34, the subject matter of Example 1 is further configured such that the sensor is a continuity sensor. 
     In Example 35, the subject matter of Example 34 is further configured such that the sensor includes a plurality of moveable features that extend from either a back panel, top panel, or bottom panel of the strike box into the opening. 
     In Example 36, the subject matter of Example 35 is further configured such that the plurality of moveable features include a free end that may be abutted by the bolt when the bolt is inserted into the opening. 
     In Example 37, the subject matter of Example 35 is further configured such that the plurality of moveable features are comprised of brushes. 
     In Example 38, the subject matter of Example 34 is further configured such that the sensor is comprises of one or more leaf springs. 
     Example 39 provides a lock assembly for a door with a latch assembly coupled to the door and including an extendable bolt. The lock assembly includes a strike assembly coupled to a jamb corresponding to the door. The strike assembly is configured to receive the bolt of the bolt assembly to secure the door to the jamb. A sensor assembly includes a sensor located within an opening formed in a strike box of the strike assembly. The sensor is configured to detect whether the bolt of the bolt assembly is encompassed by the strike box. The sensor assembly is configured to interact with a surface of the bolt when the bolt is located within the opening.