Abstract:
A dual lock system includes a housing for enclosing an actuating mechanism, a latch bolt, a dead bolt, a stop block, a lock core, and a safe therein. Upper and lower openings are provided in a faceplate to allow extension and retraction of the latch bolt and the dead bolt. Two upper actuating plates are pivotable by operation of the inside handle and the outside handle, respectively. When the dual lock assembly is in a locked status, rotation of the inside handle is allowed to simultaneously retract the deadbolt and the latch bolt, yet rotation of the outside handle is prohibited by a stop piece of the stop block. The latch bolt can be rotated through 180° when extended.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a dual lock assembly with simultaneous retraction of a latch bolt and deadbolt by an inside lever handle. The present invention also relates to a dual lock with a latch bolt that can be inverted in response to either a left-handed door or a right-handed door. 
     2. Description of the Related Art 
     FIG. 8 of the drawings illustrates a lock assembly including a latch bolt  14 ′ that can be retracted by rotation of inside or outside handle  11 ′ and an auxiliary lock  12 ′ having a dead bolt  15 ′ that can be retracted by an inside turnknob  16 ′ or by a proper key from outside. When in an emergency, one has to turn the turnknob  16 ′ first and then turn the inside handle. This is inconvenient and sometimes causes deadly delay. 
     SUMMARY OF THE INVENTION 
     It is a primary object of the present invention to provide a dual lock assembly that includes a latch bolt and a deadbolt which can be simultaneously unlatched by simple operation of the inside handle, rotation of the turnknob, or by a proper key. 
     It is another object of the present invention to provide a dual lock assembly having a latch bolt that can be inverted in response to either a left-handed door or a right-handed door. 
     The dual lock system in accordance with the present invention includes two upper actuating plates that are respectively pivoted under operation of the inside handle and outside handle to drive a lower actuating plate. A stop block has a stop piece for preventing rotation of the lower actuating plate. Namely, the deadbolt and the latch bolt can be retracted by rotation of the inside handle when the dual lock system is in a locked status, while preventing rotation of the outside handle. The latch bolt can be rotated through 180° so as to be used in either left-handed or right-handed door. 
    
    
     Other objects, specific advantages, and novel features of the invention will become more apparent from the following detailed description and preferable embodiments when taken in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of a dual lock assembly in accordance with the present invention; 
     FIG. 2 is a front view of the dual lock assembly in accordance with the present invention; 
     FIG. 3 is a sectional view taken along line  3 — 3  in FIG. 2; 
     FIG. 4 is a view similar to FIG. 2, illustrating retraction of the deadbolt and the latch bolt; 
     FIG. 5 is a sectional view taken along line  5 — 5  in FIG. 4; 
     FIG. 6 is a view similar to FIG. 2, wherein the latch bolt is inverted; 
     FIG. 7 is a sectional view taken along line  7 — 7  in FIG. 6; and 
     FIG. 8 is an exploded perspective view of a conventional door lock assembly. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 2, a dual lock assembly in accordance with the present invention generally includes a housing  1  for accommodating an actuating mechanism  2 , a latch bolt  3 , a deadbolt  4 , a stop block  5 , a lock core  6 , and a safe  7 . The housing  1  includes a side wall with positioning holes  11  through which fasteners  12  are extended to secure the housing  1  to a doorplate. After accommodating the above-mentioned components in the housing  1 , a plate  13  is provided for enclosure. The housing  1  includes a latch bolt opening  14  and a deadbolt opening  15  through which the latch bolt  3  and the deadbolt  4  extend/retract, respectively. The housing  1  further includes a rectilinear slot  16  for guiding rectilinear movement of the stop block  5 . The housing  1  and the plate  13  include aligned windows  17  and  131  through which a stop piece  51  is passable so as to be optionally secured to one of two sides of the stop block  5 . The housing  1  and the plate  13  further include aligned slots  18  and  132  for positioning the lock core  6 . 
     The drive mechanism  2  includes two upper actuating plates  21  operably connected to an inside handle  22  and an outside handle  22 , respectively. An elastic element  23  is provided to return the respective actuating plate  21  after rotation of the actuating plate  21 . The respective actuating plate  21  bears against a post  19  and thus is stopped during its returning movement. During rotation of the actuating plate  21 , the latchbolt  3  is retracted and a lower actuating plate  24  is driven to rotate about a peg  101  on the housing  1 . A hook  241  on the lower actuating plate  24  moves upward to push a catch plate  25  upward during rotation of the lower actuating plate  24 . A catch  251  on the catch plate  25  is moved upward and thus disengaged from an engaging notch  41  of the deadbolt  4 . In addition, when driving force from the lower actuating plate  24  disappears, the catch plate  25  is returned by an elastic element  26 , thereby causing the catch  251  to engage with one of two engaging notches  41  of the deadbolt  4 . The catch plate  25  includes a slot  252  mounted around a peg  102  on the housing  1  to allow rectilinear movement of the catch plate  25 . 
     The latch bolt  3  moves rectilinearly by provision of the latch bolt opening  14  and a guide plate  103  secured to the housing  1  and the plate  13 . A substantially U-shape plate  31  includes an end actuatable by the upper actuating plate  21  to urge a rod  38  extended from the latch bolt  3  to retract, thereby retracting the latch bolt  3  into the housing  1 . Elastic elements  32  and  33  are provided to return the latch bolt  3 . During returning of the latch bolt  3  (namely, the latch bolt  3  is extended outside the latch bolt opening  4  and the U-shape plate  31  bears against a compression plate  34 ), the compression plate  34  pivots about a pivotal member  104  until it is stopped by a stop  105 , as the compression plate  34  is biased by an elastic member  35  having an elastic coefficient greater than that of the elastic elements  32  and  33 . Thus, when the latch bolt  3  is returned under action of the elastic elements  32  and  33 , the latch bolt  3  is stopped when the U-shape plate  31  and the compression plate  34  contact with each other. At this time, the latch bolt  3  is not completely beyond the latch bolt opening  14 . The rod  38  of the latch bolt  3  further includes a slot  36  such that a tool, e.g., a screwdriver may be used to push and rotate the rod  38 . When the latch bolt  3  is pushed by a tool, the compression plate  34  is forced to pivot, thereby urging the latch bolt  3  to pass through the latch bolt opening  14  completely. Thus, the latch bolt  3  is capable of being rotated through 180° by means of driving the latch bolt  3  by the tool, as shown in FIGS. 3 and 7. 
     The deadbolt  4  moves rectilinearly by provision of the peg  102  on the housing  1  and the deadbolt opening  15 . The deadbolt  4  includes a notch  43  that is engagable with and thus driven by a drive block  61  of the lock core  6 . The deadbolt  4  further includes two engaging notches  41 . When the deadbolt  4  is moved to its locked position, one of the engaging notches  41  is engaged with the catch  251  of the catch plate  25 , thereby retaining the deadbolt  4  in place. The deadbolt  4  is in pivotal connection with a follower plate  45  by a pivotal member  44 . An end of the follower plate  45  is engaged on an engaging notch  37  of the latch bolt  3 . Thus, retraction of the deadbolt  4  under actuation of the lock core  6  also causes retraction of the latch bolt  3 . The deadbolt  4  further includes a protruded peg  46  that is operably connected to a return follower plate  54  driven by the stop block  5 , thereby allowing transmission therebetween. An elastic element  47  is provided to bias the deadbolt  4  to extend beyond the deadbolt opening  15 . 
     The stop block  5  includes a through-hole  56  to allow the stop piece  51  to be optionally secured to one of two sides of the stop block  5 . The stop piece  51  is provided to stop rotation of one of the actuating plates  21 . The stop block  5  includes a rod  58  that is guided by a hole  108  of the housing  1 . The stop block  5  further includes a protrusion  52  that is slidably guided by a rectilinear slot  16  on the housing  1 . Thus, the stop block S moves rectilinearly. The stop block  5  further includes a channel  53  for receiving the return follower plate  54  and an end of a drive plate  55 . The return follower plate  54  includes a central fulcrum  541  that is pivotally mounted. An end of the return follower plate  54  is operably connected to the peg  46  of the deadbolt  4 , thereby allowing transmission therebetween. The other end of the return follower plate  54  is operably connected to the drive plate  55 . The return follower plate  54  and the drive plate  55  are restrained in the channel  53  of the stop block  5 . The drive plate  55  is rotatable about its central fulcrum  551 . An end of the drive plate  55  extends into the channel  53  and operably connected to an end of the return follower plate  54 . An elastic element  57  is provided to the drive plate  55  for biasing the other end of the drive plate  55  to a position that allows retraction of the latch bolt  3 . Thus, when the inside handle  22  is rotated to cause retraction of the latch bolt  3 , the drive plate  55  urges the return follower plate  54  to rotate and causes the stop piece  51  of the stop block  5  to move away from the upper actuating plate  21  for the outside handle  22 , thereby accomplishing the unlatching function. In the mean time, the other end of the return follower plate  54  bears against the peg  46  to cause synchronous retraction of the deadbolt  4  for unlatching. 
     The lock core  6  includes two exposed ends that are respectively secured in the positioning slot  18  of the housing  1  and the positioning slot  132  of the plate  13 . A proper key may be inserted into a keyway (not shown) in an end of the lock core  6  and then rotated for unlatching. The other end of the lock core  6  is engaged with a turnknob  62  for direct rotation of the drive block  61  upon manual operation. Orientation of the keyway can be changed after detaching the plate  13 . Namely, the keyway can be positioned adjacent to the housing  1  or the plate  13  such that the keyway always faces outward and that the turnknob  62  is located indoors. Screw holes  63  are provided to allow extension of fasteners  12  for securing the lock core  6  in place. 
     The safe  7  includes a fixing plate  71  secured to the housing  1 . An end of the safe  7  is biased by an elastic element  72  and thus extends beyond a hole  107  of the housing  1 . The other end of the safe  7  includes a hook  73  that is operably connected to a protrusion  75  of a safe piece  74  which, in turn, is pivotally connected to the housing  1 . An end of the safe piece  74  is pivoted to the housing  1  and biased by an elastic element  76  to urge the other end of the safe piece  74  to a position for obstructing retraction of the latch bolt  3 . When the dual lock assembly is mounted to a doorplate and the doorplate is in a closed status, the protruded safe  7  is moved into the housing  1  such that the safe piece  74  is biased by the elastic element  76  to a position for obstructing retraction of the latch bolt  3 . Thus, retraction of the latch bolt  3  is not allowed. In addition, unauthorized opening of the door by means of forcibly exerting an inward force to the latch bolt  3  is prevented. An upper end of the safe piece  74  is operably connected to a bottom of the engaging notch  37  of the latch bolt  3 . When the U-shape plate  31  on the latch bolt  3  is pulled inward, the safe piece  74  is moved downward by the bottom of the engaging notch  37 . 
     FIGS. 2 and 3 illustrate an application of the dual lock assembly of the invention, wherein the latch bolt  3  and the deadbolt  4  are in extended positions (latching positions). Elastic elements  32  and  33  cause extension of the latch bolt  3 . Extension of the deadbolt  4  is caused by use of a proper key or rotation of the turnknob  62  and via transmission of the drive block  61  that engages with the notch  43  of the deadbolt  4 . During extension of the deadbolt  4 , the peg  46  of the deadbolt  4  causes rotation of the return follower plate  54  to pivot about its central fulcrum  541 . The return follower plate  54  actuates the drive plate  55  and the stop block  5 . The stop piece  51  of the stop block  5  is moved to a position close to the upper actuating plate  21  for the outside handle  22 , thereby preventing rotation of the outside handle  12 . Meanwhile, the other end of the drive plate  55  is moved to a position for obstructing retraction of the latch bolt  3 . In addition, the safe  7  is moved inward by the door frame such that the distal end of the safe piece  74  is moved to a position for obstructing retraction of the latch bolt  3 . Thus, the intention of unauthorized opening of the door by means of forcibly exerting an inward force to the latch bolt  3  by a tool is prevented. This is because the U-shape plate  31  on the latch bolt  3  is not moved such that retraction of the latch bolt  3  is stopped by the safe piece  74 . 
     Referring to FIGS. 4 and 5, when the inside handle  22  is rotated, the upper actuating plate  21  for the inside handle  22  urges the U-shape plate  31  on the latch bolt  3  to move along the rod  38  of the latch bolt  3  and thus compresses the elastic elements  32  and  33 . Movement of the U-shape plate  31  causes downward movement of the safe piece  74 . In addition, the upper actuating plate  21  urges the lower actuating plate  24  to rotate such that the hook  241  of the lower actuating plate  24  pushes the catch plate  25  upward, thereby causing disengagement of the catch  251  from the engaging notch  41 . Further rotation of the upper actuating plate  21  causes retraction of the latch bolt  3 . It is noted that the safe piece  74  has been moved to a position not obstructing retraction of the latch bolt  3 . Retraction of the latch bolt  3  also causes the other end of the drive plate  55  to actuate the return follower plate  54  and the stop block  5 . The stop piece  51  of the stop block  5  is moved to a position not obstructing rotation of the upper actuating plate  21  for the outside handle  22 . In addition, the return follower plate  54  actuates the peg  46  of the deadbolt  4  to cause simultaneous retraction of the deadbolt  4  into the housing  1 . 
     Still referring to FIGS. 2 and 3 that show the latching status of the dual lock assembly, when a proper key is used or the turnknob  62  is rotated, the drive block  61  of the lock core  6  is rotated to move the catch plate  25  upward such that the catch  251  disengages from the engaging notch  41  of the deadbolt  4 . In addition, the drive block  61  is engaged with the notch  43  of the deadbolt  4  to cause retraction of the deadbolt (FIG.  4 ). During retraction of the deadbolt  4 , the follower plate  45  is restrained by the pivotal member  44  and the protrusion  48  such that the upper end of the follower plate  45  causes the U-shape plate  31  on the latch bolt  3  to retract, thereby retracting the latch bolt  3 . 
     Referring to FIGS. 6 and 7, when the dual lock assembly requires adjustment in response to the need for a left-handed door or a right-handed door, the fasteners  12  for positioning the lock core  6  are detached to allow a change in the orientation of the lock core  6  in a manner that the turnknob  62  locates indoors. In addition, the stop piece  51  is engaged with the through-hole  56  of the stop block  5 , and a screwdriver is engaged in the slot  36  of the latch bolt  3  and pushes the latch bolt  3 , thereby causing the latch bolt  3  to disengage from the side wall of the housing  1 . Thus, the latch bolt  3  is allowed to rotate through 180° such that the inclined face (not labeled) of the latch bolt faces the doorframe. Accordingly, the dual lock assembly of the invention can be adjusted and thus used to either left-handed or right-handed door. 
     According to the above description, it is appreciated that synchronous retraction of the latch bolt and the deadbolt can be achieved by rotation of the inside handle. In addition, the dual lock assembly of the invention can be adjusted and thus used to either left-handed or right-handed door. 
     Although the invention has been explained in relation to its preferred embodiment as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention. It is, therefore, contemplated that the appended claims will cover such modifications and variations that fall within the true scope of the invention.