Patent Publication Number: US-8528946-B2

Title: Door lock with idle travel in a locking state

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a door lock and, more particularly, to a door lock mounted on a panic exit door or a passageway door and having an idle travel when the door lock is in a locking state to avoid damage to the components of the door lock. 
     A typical lock for a panic exit door or a passageway door generally includes a press bar that can be pressed to retract a latch for unlatching the door in emergency conditions as well as for normal passage. When the door lock is in a locking state, the latch can not be retracted to prevent unauthorized access. However, the press bar has a large area and, thus, imparts considerable force and causes damage to the components in the lock if the press bar is pressed with large force while the lock is in the locking state. 
     Thus, a need exists for a door lock that has an idle travel when the door lock is in a locking state to avoid damage to the components of the door lock. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention solves this need and other problems in the field of preventing damage to components of door locks mounted to panic exit doors or passageway doors by providing a door lock including a bracket adapted to be fixed to a side of a door. The door is adapted to be pivotably mounted to a door frame having a stop. A latch is mounted to the bracket and pivotable about a first axis between an extended, latching position, and a retracted, unlatching position. A follower includes a first end pivotably connected to the latch and a second end spaced from the first end of the follower along a second axis perpendicular to the first axis. A linking rod includes first and second ends spaced along the second axis. The first end of the linking rod is pivotably connected to the second end of the follower. The second end of the linking rod is movable in an unlatching direction along the second axis for moving the latch from the extended, latching position, to the retracted, unlatching position, and movable in a latching direction opposite to the unlatching direction for moving the latch from the retracted, unlatching position, to the extended, latching position. First and second brackets are adapted to be fixed to the side of the door, and each includes a sliding slot extending along a third axis perpendicular to the first and second axes. The second bracket has a spacing to the bracket along the second axis larger than the first bracket. A third bracket is adapted to be fixed to the side of the door and located between the first and second brackets along the second axis. 
     The door lock further includes first and second traction members each having first, second, and third corners. The third corner of the first traction member is pivotably connected to the first bracket by a first axle about a first pivot axis parallel to a pivot axis of the latch. The third corner of the second traction member is pivotably connected to the second bracket by a second axle about a second pivot axis parallel to the first pivot axis. The door lock further includes first and second follower elements each having first and second pivotal portions. The first pivotal portion of the first follower element is pivotably connected to the first corner of the first traction member. The first pivotal portion of the second follower element is pivotably connected to the first corner of the second traction member. A first pin extends through the sliding slot of the first bracket and the second pivotal portion of the first follower element and defines a third pivot axis parallel to the first pivot axis. A second pin extends through the sliding slot of the second bracket and the second pivotal portion of the second follower element and defines a fourth axis parallel to the first pivot axis. The first follower element drives the first traction member to pivot about the first pivot axis when the first pin moves in the sliding slot of the first bracket along the third axis. The second follower element drives the second traction member to pivot about the second pivot axis when the second pin moves in the sliding slot of the second bracket along the third axis. The first and second pins are pivotably connected to an operative member. 
     The door lock further includes a connecting member having first and second ends spaced along the second axis and a push slot between the first and second ends. The first end of the connecting member is pivotably mounted to the second corner of the first traction member. The connecting member moves along the second axis when the first traction member pivots about the first pivot axis. A follower plate includes front and rear ends spaced along the second axis and first and second grooves between the front and rear ends. The first groove is located between the second groove and the front end. The second groove is located between the first groove and the rear end. The follower plate further includes an extension extending from an edge of the follower plate and located between the front and rear ends. A stop is formed on the extension. The extension includes an elongated slot spaced from the first groove along the third axis. The front end of the follower plate is removably engaged with the second end of the linking rod. The follower plate is mounted to the connecting member. The second groove of the follower plate is aligned with the push slot of the connecting member. The connecting member is slideable relative to the follower plate along the second axis. A peg extends through the first groove of the follower plate. A sleeve is mounted around the connecting member. A pin extends through the push slot of the connecting member, the second groove of the follower plate, and the sleeve. The peg pushes the connecting member to slide along the second axis when the first traction member pivots about the first pivot axis. 
     The door lock further includes a connecting rod fixed to the second end of the connecting member. The connecting rod includes a connecting end and a pull end spaced from the connecting end along the second axis. The connecting end of the connecting rod is fixed to the second end of the connecting member. The pull end of the connecting rod is pivotably connected to the second corner of the second traction member. The connecting rod moves along the second axis when the second traction member pivots about the second pivot axis. A stop member includes first and second ends and a pivot hole between the first and second ends. The first end of the stop member faces the stop of the follower plate. A third axle extends through the third bracket and the pivot hole of the stop member and defines a fifth pivot axis parallel to the first pivot axis. The stop member is pivotable about the fifth pivot axis. A draw bar includes a head connected to the second end of the stop member. The draw bar is operable to move along the second axis between an extended position and a retracted position. When in the retracted position, the draw bar has a spacing to the latch larger than that in the extended position. When the draw bar is in the extended position, the first end of the stop member is spaced from the stop of the follower plate. When the draw bar is moved from the extended position to the retracted position, the stop member pivots about the fifth pivot axis to abut the first end of the stop member against the stop of the follower plate. 
     When the draw bar is in the extended position and when the operative member is operated to move the first and second pins along the third axis towards the door, the first and second follower elements pivot the first and second traction members about the first and second pivot axes. The second corners of the first and second traction members move the connecting member and the connecting rod in the unlatching direction. The connecting member causes the pin to push and move the follower plate in the unlatching direction along the second axis. The connecting rod causes the linking rod to move in the unlatching direction along the second axis, moving the latch from the extended, latching position to the retracted, unlatching position. 
     When the draw bar is in the retracted position and when the operative member is operated to move the first and second pins along the third axis towards the door, the first and second follower elements pivot the first and second traction members about the first and second pivot axes. The second corners of the first and second traction members move the connecting member and the connecting rod in the unlatching direction. Movement of the follower plate in the unlatching direction is stopped by the first end of the stop member. The first groove of the follower plate allows movement of the peg in the unlatching direction without moving the follower plate. The push slot of the connecting member allows movement of the connecting member in the unlatching direction without moving the pin, preventing movement of the linking rod in the unlatching direction. The latch remains in the extended, latching position. 
     When the draw bar is in the extended position and when the latch is pressed by the stop on the door frame and pivoted from the extended, latching position to the retracted, unlatching position, the latch moves the follower element in the unlatching direction to move the linking rod in the unlatching direction. The linking rod causes the follower plate to move in the unlatching direction. The peg received in the first groove of the follower plate and the pin received in the second groove of the follower plate are not moved. The elongated slot of the follower plate allows movement of the follower plate relative to the third corner of the first traction member without pivoting the first traction member about the first pivot axis. 
     The present invention will become clearer in light of the following detailed description of an illustrative embodiment of this invention described in connection with the drawings. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The illustrative embodiment may best be described by reference to the accompanying drawings where: 
         FIG. 1  shows a diagrammatic top view of a door lock according to the present invention and a door to which the door lock is mounted, with the door lock in a locked position and with portions cross sectioned. 
         FIG. 2  shows a partial, exploded, perspective view of the door lock of  FIG. 1 . 
         FIG. 3  shows an exploded, perspective view of a latch device of the door lock of  FIG. 1 . 
         FIG. 4  shows an enlarged, exploded, perspective view of some components of the latch device of  FIG. 3 . 
         FIG. 5  shows a partial, exploded, perspective view of an operative device of  FIG. 2 . 
         FIG. 6  shows a partial, exploded, perspective view of the operative device of  FIG. 5 . 
         FIG. 7  shows an exploded, perspective view of an operative member of the door lock of  FIG. 1 . 
         FIG. 8  shows a partial, enlarged, cross-sectional view of the door and the door lock of  FIG. 1 , with the door in an open position and with a linking rod of the door lock in a first limit position of an idle travel thereof. 
         FIG. 9  shows a cross-sectional view taken along section line  9 - 9  of  FIG. 8 . 
         FIG. 10  shows a cross-sectional view taken along section line  10 - 10  of  FIG. 9 . 
         FIG. 11  shows a cross-sectional view taken along section line  11 - 11  of  FIG. 10 . 
         FIG. 12  shows an enlarged view of the operative device of  FIG. 1 . 
         FIG. 13  shows a cross-sectional view taken along section line  13 - 13  of  FIG. 12 . 
         FIG. 14  shows a partial, cross sectional view of the door and the door lock of  FIG. 1 , illustrating closing of the door. 
         FIG. 14A  shows a partial, enlarged, cross sectional view of the latch device after the door in  FIG. 14  is completely closed. 
         FIG. 15  shows a cross-sectional view taken along section line  15 - 15  of  FIG. 14A . 
         FIG. 16  shows a cross-sectional view taken along section line  16 - 16  of  FIG. 15 . 
         FIG. 17  shows a cross-sectional view taken along section line  17 - 17  of  FIG. 15 . 
         FIG. 18  shows a view similar to  FIG. 14A , with the linking rod of the door lock in a second limit position of the idle travel thereof. 
         FIG. 19  shows a cross-sectional view taken along section line  19 - 19  of  FIG. 18 . 
         FIG. 20  shows a view similar to  FIG. 1 , with an operative member pressed to retract a latch. 
         FIG. 21  shows an enlarged view of the latch device of  FIG. 20 . 
         FIG. 22  shows a view similar to  FIG. 1 , with a draw bar moved backward by a driving device. 
         FIG. 23  shows a view similar to  FIG. 22 , with the operative member pressed to retract the latch. 
         FIG. 24  shows a cross-sectional view taken along section line  24 - 24  of  FIG. 23 . 
     
    
    
     All figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the preferred embodiment will be explained or will be within the skill of the art after the following teachings of the present invention have been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following teachings of the present invention have been read and understood. 
     Where used in the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms “first”, “second”, “third”, “fourth”, “fifth”, “upper”, “lower”, “front”, “rear”, “inner”, “outer”, “end”, “portion”, “section”, “longitudinal”, “lateral”, “inward”, “leftward”, “spacing”, “length”, “width”, “height”, and similar terms are used herein, it should be understood that these terms have reference only to the structure shown in the drawings as it would appear to a person viewing the drawings and are utilized only to facilitate describing the invention. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A door lock according to the present invention is shown in the drawings and generally designated  2 . Door lock  2  includes an operational device  20  and a latch device  30  mounted to a door  1  pivotable relative to a door frame  11  having rectangular or inverted U-shaped cross sections. Door frame  11  is fixed to a wall of a passageway and includes an inner face  11 A and a stepped portion  11 B. Stepped portion  11 B includes an abutment face  11 C extending perpendicularly from an edge of inner face  11 A and a face  11 D extending perpendicularly to abutment face  11 C and parallel to and spaced from inner face  11 A. Door  1  includes first and second sides  1 A and  1 B. An end of door  1  is pivotably mounted to door frame  11 , and door  1  is movable between an open position and a closed position. When door  1  is in the closed position, first side  1 A of door  1  abuts abutment face  11 C of door frame  11 . An end face of the other end of door  1  adjacent to stepped portion  11 B is spaced from abutment face  11 C. A stop  12  is mounted to inner face  11 A of door frame  11 . 
     According to the form shown, latch device  30  includes a base  31  fixed to first side  1 A of door  1  by fasteners such as screws, bolts, or the like. Base  31  includes a plurality of fixing holes  311 . Latch device  30  further includes a bracket  33  having substantially U-shaped cross sections. Bracket  33  includes parallel, spaced first and second sidewalls  331  spaced along a first axis X. Bracket  33  further includes an interconnecting wall  336  interconnected between first and second sidewalls  331  and extending along first axis X. Each of first and second sidewalls  331  has a plurality of engaging portions  338 . Fasteners  45  are extended through engaging portions  338  into fixing holes  311  to fix bracket  33  to base  31 . Each of first and second sidewalls  331  further includes first and second sections  332  and  333  spaced along a second axis Y perpendicular to first axis X. Aligned pin holes  335  are defined in first sections  332 , and aligned holes  339  are defined in second sections  333 . First and second sidewalls  331  further include aligned pin holes  330  intermediate holes  339  and pin holes  335 . Furthermore, first and second sidewalls  331  include aligned slots  334  intermediate holes  339  and pin holes  335 . Interconnecting wall  336  includes two guide slots  337  extending along second axis Y and spaced along first axis X. Interconnecting wall  336  further includes a bulged section  395  spaced from guide slots  337  along second axis Y. Bulged section  395  defines a cavity  397  in an inner face of interconnecting wall  336  and has a hole  396  extending along a third axis Z perpendicular to first and second axes X and Y. 
     According to the form shown, latch device  30  further includes a latch  38  having triangular cross sections. Specifically, latch  38  includes a first, inner face  382  having first and second ends, a second, arcuate face  385  having a first end interconnected to the first end of first face  382  and a second end, and a third, outer face  386  having first and second ends interconnected to the second ends of the first and second faces  382  and  385 . A pivotal portion  381  is formed at a corner between the second end of first face  382  and the first end of third face  386  and includes a pin hole  387  extending along first axis X. A latch pin  42  is extended through pin holes  335  of bracket  33  and pin hole  387  to pivotably connect latch  38  to bracket  33 , allowing latch  38  to pivot between an extended, latching position outside bracket  33  ( FIGS. 1 ,  8 , and  14 A) and a retracted, unlatching position inside bracket  33  ( FIGS. 20 and 21 ) about a pivot axis defined by latch pin  42  extending along first axis X. First face  382  includes a coupling block  383  formed thereon and having a pivot hole  384  adjacent pin hole  387 . A cover  315  is mounted to base  31  to enclose latch device  30 . Cover  315  includes an opening  316  through which latch  38  is movable. 
     According to the form shown, a linking rod  730  is mounted between and spaced from first and second sidewalls  331  of bracket  33  along first axis X. Linking rod  730  has first and second ends  732  and  734  spaced along second axis Y. Linking rod  730  further includes upper and lower faces  736  and  738  spaced along first axis X. First end  732  of linking rod  730  includes a slot  744  extending along second axis Y and having a front end  746  and a rear end  748  that is spaced from front end  746  along second axis Y and that has a spacing to first end  732  of linking rod  730  larger than front end  746 . Slot  744  extends from upper face  736  through lower face  738  of linking rod  730  and is aligned with slots  334  of brackets  33 . A limiting pin  44  is slideably extended through slots  334  of bracket  33  and slot  744  of linking rod  730 . Linking rod  730  can move idly along second axis Y without actuating limiting pin  44 . The idle travel of linking rod  730  is equal to a length of slot  744  along second axis Y. Specifically, when linking rod  730  is between first and second limit positions of its idle travel along second axis Y relative to limiting pin  44 , limiting pin  44  received in slot  744  is not moved. However, when movement of linking rod  730  exceeds the first limit position ( FIG. 8 ) or the second limit position ( FIG. 18 ), the limiting pin  44  is moved along second axis Y together with linking rod  730 . First end  732  of linking rod  730  further includes a lateral face  740  extending between and perpendicular to upper and lower faces  736  and  738  of linking rod  730 . A protrusion  742  protrudes from lateral face  740  along third axis Z and between upper and lower faces  736  and  738 . Second end  734  of linking rod  730  includes an insertion block  752  formed on each of upper and lower faces  736  and  738 . Linking rod  730  further includes a limiting slot  750  between slot  744  and insertion blocks  752  and extending along second axis Y. A pin  46  is extended through holes  339  of bracket  33  and limiting slot  750  to assist in stable movement of linking rod  730  along second axis Y between first and second sidewalls  331  of bracket  33 . Second end  734  of linking rod  730  further includes a hole  754  extending from upper face  736  through lower face  738 . 
     According to the form shown, a follower  32  is pivotably connected to coupling block  383  of latch  38 . Follower  32  is substantially U-shaped in cross section and includes parallel first and second side plates  324  spaced along first axis X and an interconnecting plate  325  interconnected between first and second side plates  324 . Each of first and second side plates  324  includes first and second ends  321  and  322  spaced along second axis Y and an extension  323  extending from an intermediate portion thereof in a direction away from and perpendicular to interconnecting plate  325 . First ends  321  of first and second side plates  324  include aligned pivot holes  326 . A pivot  41  is extended through pivot hole  384  of coupling block  383  and pivot holes  326  of follower  32 , allowing pivotal movement of follower  32  relative to latch  38  about a pivot axis defined by pivot  41  and parallel to and spaced from the pivot axis of latch pin  42 . Extensions  323  of follower  32  are slideably extended through guide slots  337  of bracket  33 . Second ends  322  of first and second side plates  324  include aligned pin holes  327  through which limiting pin  44  extends. When linking rod  730  is in the first limit position of its idle travel, limiting pin  44  is in rear end  748  of slot  744  ( FIG. 14A ). On the other hand, when linking rod  730  is in the second limit position of its idle travel, limiting pin  44  is in front end  746  of slot  744  ( FIG. 18 ). Specifically, limiting pin  44  received in slot  744  is not moved when linking rod  730  is moved from the first limit position to the second limit position in an unlatching direction along second axis Y or moved from the second limit position to the first limit position in a latching direction opposite to the unlatching direction. However, when linking rod  730  in the second limit position ( FIG. 18 ) is further moved leftward (as viewed from  FIG. 18 ) in the unlatching direction away from latch  38  along second axis Y, limiting pin  44  is moved leftward along second axis Y and pivots latch  38  from the latching position ( FIGS. 1 and 14A ) to the retracted, unlatching position ( FIGS. 20 and 21 ). 
     According to the form shown, a locking member  36  is mounted between first and second sidewalls  331  of bracket  33  and spaced from first end  732  of linking rod  730 . Locking member  36  is substantially E-shaped in cross section. Specifically, locking member  36  includes front and rear faces  361  and  362  spaced along second axis Y. Locking member  36  further includes first and second lateral faces  360   a  and  360   b  extending perpendicularly to and between front and rear faces  361  and  362 . First lateral face  360   a  faces linking rod  730  and includes a lump  36   a  formed on a rear portion thereof distant to front face  361 . Lump  36   a  includes a groove  366  facing protrusion  742  of linking rod  730  and having an end opening  368 . End opening  368  has a spacing to front face  361  along second axis Y smaller than groove  366 . Furthermore, end opening  368  has increasing widths along first axis X away from rear face  362  of locking member  36  ( FIG. 4 ). Locking member  36  further includes top and bottom faces  36   b  and  36   c  spaced along first axis X and extending perpendicularly to and between front and rear faces  361  and  362  and extending perpendicularly to and between first and second lateral faces  360   a  and  360   b . A vertical hole  367  extends from top face  36   b  through bottom face  36   c  of locking member  36 . A guide pin  43  is extended through pin holes  330  of bracket  33  and vertical hole  367  of locking member  36 , allowing movement of locking member  36  between an upper, unlocking position ( FIG. 9 ) and a lower, locking position ( FIG. 17 ) spaced from the upper, unlocking position along first axis X. Two guide grooves  363  extend from front face  361  towards but spaced from rear face  362  along second axis Y. Guide grooves  363  are spaced along first axis X and spaced from top and bottom faces  36   b  and  36   c  of locking member  36 . Furthermore, guide grooves  363  are spaced from groove  366  along third axis Z. A guide piece  364  in the form shown as a lug is formed on rear face  362  of locking member  36  and integrally formed with lump  36   a  as a single continuous monolithic member. Guide piece  364  includes a narrower section  365  and a wider section  369 . Wider section  369  has a spacing to second lateral face  360   b  along third axis Z larger than narrower section  365  and has a width along first axis X larger than that of narrower section  365 . Wider section  369  includes triangular cross sections (when viewing rear face  362  along second axis Y) and has decreasing widths toward narrower section  365  along third axis Z. 
     According to the form shown, a substantially U-shaped swaying plate  34  is pivotably mounted in bracket  33 . Swaying plate  34  includes parallel first and second side boards  345  spaced along first axis X and received between sidewalls  331  of bracket  33 . Swaying plate  34  further includes an interconnecting board  346  interconnected between first and second side boards  345 . Each of first and second side boards  345  is substantially L-shaped and includes a first end  341  interconnected to interconnecting board  346 , a second end  342 , and a pivotal portion  343  on an intermediate portion intermediate the first and second ends  341  and  342 . Second ends  342  of first and second side boards  345  are received between first and second sidewalls  331  of bracket  33 . First ends  341  of first and second side boards  345  of swaying plate  34  are movable through opening  316  between a first, outer position outside of cover  315  ( FIG. 8 ) and a second, inner position partially received in cover  315  ( FIG. 14A ). Latch pin  42  is extended through aligned pin holes in pivotal portions  343  of swaying plate  34  to allow pivotal movement of swaying plate  34  about the pivot axis defined by latch pin  42 . Each of first and second side boards  345  includes a drive piece  344  formed on the intermediate portion thereof and adjacent to first end  341  thereof. Drive pieces  344  extend toward each other along first axis X. 
     According to the form shown, a limiting block  35  is mounted to swaying plate  34  to move therewith. Limiting block  35  is movable between a holding position ( FIGS. 8 and 10 ) corresponding to the first, outer position ( FIG. 8 ) of first ends  341  of first and second side boards  345  of swaying plate  34  and a releasing position ( FIGS. 14A and 15 ) corresponding to the second, inner position ( FIG. 14A ) of first ends  341  of first and second side boards  345  of swaying plate  34 . Limiting block  35  includes first and second lateral faces  357   a  and  357   b  spaced along third axis Z. Limiting block  35  further includes front and rear faces  358  and  359  spaced along second axis Y and extending perpendicularly to and between first and second lateral faces  357   a  and  357   b . Upper and lower ears  350  are formed on upper and lower ends of first lateral face  357   a  and spaced along first axis X. Each of upper and lower ears  350  has an engaging groove  354  formed in a front face thereof. Second ends  342  of first and second side boards  345  of swaying plate  34  are coupled with engaging grooves  354  to allow joint pivotal movement of swaying plate  34  and limiting block  35 . A through-hole  355  extends from first lateral face  357   a  through second lateral face  357   b  along third axis Z and is intermediate upper and lower ears  350 . A guide groove  356  is formed in an intermediate portion of front face  358  of limiting block  35  and extends from first lateral face  357   a  through second lateral face  357   b  along third axis Z, leaving upper and lower protrusions  351  on upper and lower ends of front face  358 . Guide groove  356  is substantially trapezoidal in cross section and includes a first, larger end  352  in first lateral face  357   a  and a second, smaller end  353  in second lateral face  357   b . Second, smaller end  353  is spaced from first, larger end  352  along third axis Z. Second, smaller end  353  has a width along first axis X smaller than a width of the first, larger end  352  along first axis X. Specifically, guide groove  356  has decreasing widths from first, larger end  352  toward second, smaller end  353 . Second, smaller end  353  of guide groove  356  has a minimum width along first axis X smaller than a maximum width of wider section  369  of guide piece  364  of locking member  36  along first axis X. 
     According to the form shown, a guide rod  39  is mounted between limiting block  35  and interconnecting wall  336  of bracket  33 . Specifically, guide rod  39  includes a head  391  and a shank  392  extending from a side of head  391  and having an end slideably received in through-hole  355  of limiting block  35 . The other side of head  391  is domed and includes a tip  399  extending through hole  396  of bulged section  395  to prevent head  391  from disengaging from interconnecting wall  336 . An outer periphery of the domed side of the head  391  slideably abuts an inner periphery of hole  396  of bulged section  395  so that head  391  can swivel against the inner periphery of hole  396  when shank  392  moves together with limiting block  35 . A spring  393  is mounted around shank  392  between the side of head  391  and second lateral face  357   b  of limiting block  35 . Note that a portion of head  391  outside of hole  396  is received in cavity  397  to avoid interference in operation of guide rod  39  and other components. 
     According to the form shown, operative device  20  is coupled with second end  734  of linking rod  730 . Operative device  20  includes a substantially U-shaped casing  538  fixed to first side  1 A of door  1 . Casing  538  includes two lateral walls and a connecting wall between the lateral walls, defining a compartment  540  having an opening  542 . Opening  542  has a width along first axis X slightly smaller than the width of compartment  540  along first axis X. Two ribs  544  are formed on an inner face of each lateral wall and located in compartment  540 . An end of casing  538  is adjacent to a side of cover  315  distal to opening  316 . A cover plate  546  is mounted in opening  542  and has a length along second axis Y smaller than that of opening  542  along second axis Y, such that an end of opening  542  adjacent to cover  315  is not covered by cover plate  546 . 
     According to the form shown, operative device  20  further includes a mounting plate  548  having cross sections with alternately disposed protruded portions and recessed portions. Mounting plate  548  includes two engagement ends  551  spaced along first axis X. A recess  549  is defined between engagement ends  551 . Mounting plate  548  further includes four first positioning holes  550 , four second positioning holes  552 , four third positioning holes  554 , two fourth positioning holes  556 , and a fixing hole  555 . Each third positioning hole  554  is located between first positioning holes  550  and fixing hole  555 . Second positioning holes  552  are located between fixing hole  555  and fourth positioning holes  556 . Four pads  557  are fixed to a side of mounting plate  548 , with two pads  557  located between an end of mounting plate  548  and first positioning holes  550 , and the other two pads  557  located between second positioning holes  552 . The end of mounting plate  548  is adjacent to the side of cover  315  distal to opening  316 . Each of engagement ends  551  of mounting plate  548  is engaged with a corresponding rib  544 . 
     According to the form shown, operational device  20  further includes substantially U-shaped first and second brackets  558  spaced along second axis Y. Second bracket  558  has a spacing to bracket  33  along second axis Y larger than first bracket  558 . Each of first and second brackets  558  includes first and second plates  560  spaced along first axis X and a connecting plate  562  extending between first and second plates  560 . Each of first and second plates  560  includes a sliding slot  564  and an axle hole  568 . A pair of lugs  570  is formed on each of two ends of connecting plate  562  of each of first and second brackets  558 . Each axle hole  568  is located between connecting plate  562  and a corresponding sliding slot  564 . An insertion groove  567  is formed on an edge of each of first and second plates  560 . Each lug  570  of first bracket  558  is aligned with one of first positioning holes  550  and is fixed by a first positioning member  572  (such as a screw). Each lug  570  of second bracket  558  is aligned with one of second positioning holes  552  and is fixed by a second positioning member  586  (such as a screw). First and second brackets  558  are received in compartment  540  of casing  538 . Sliding slots  564  of first and second brackets  558  are adjacent to opening  542  of casing  538 . A first axle  616  is pivotably received in axle holes  568  of first bracket  558 . A first pin  622  is slideably received in sliding slots  564  of first bracket  558 , such that first pin  622  can slide in sliding slots  564  of first bracket  558  along third axis Z. A second axle  618  is pivotably received in axle holes  568  of second bracket  558 . A second pin  624  is slideably received in sliding slots  564  of second bracket  558 , such that second pin  624  can slide in sliding slots  564  of second bracket  558  along third axis Z. 
     According to the form shown, operational device  20  further includes a third bracket  588 . Third bracket  588  includes first and second walls  590  spaced along first axis X and a connecting wall  592  extending between first and second walls  590 . Each of first and second walls  590  includes a movement slot  594  and an axle hole  595 . Each movement slot  594  is located between a corresponding axle hole  595  and connecting wall  592  along third axis Z. An arm  596  extends from an edge of each of first and second walls  590  and has an engagement tab  598 . Engagement tabs  598  of arms  596  are aligned with and spaced from each other along first axis X. A pair of lugs  600  is formed on each of two ends of connecting wall  592  of third bracket  588 . Each lug  600  of third bracket  588  is aligned with one of third positioning holes  554  of mounting plate  548  and is fixed by a third positioning member  602  (such as a screw). A third axle  620  is pivotably received in axle holes  595  of third bracket  588 . A third pin  626  is slideably received in movement slots  594  of third bracket  588 , such that third pin  626  can slide in movement slots  594  of third bracket  588  along third axis Z. 
     According to the form shown, operative device  20  further includes a substantially L-shaped fixing plate  604  mounted to mounting plate  548  and a switch  612  mounted to the fixing plate  604 . Fixing plate  604  includes a first section  606  extending perpendicularly to third axis Z and a second section  608  extending perpendicularly to first axis X. A protrusion  610  extends from a side of first section  606  along third axis Z. Switch  612  is fixed to second section  608  and includes an actuating plate  614 . A screw  603  is extended through fixing hole  555  of mounting plate  548  into first section  606  of fixing plate  604 . Protrusion  610  is received in recess  549  of mounting plate  548 . Thus, fixing plate  604  is securely fixed to mounting plate  548 . Switch  612  is received in compartment  540  of casing  538  with actuating plate  614  facing second bracket  558 . Switch  612  is electrically connected to a burglarproof system  756  ( FIG. 1 ). 
     According to the form shown, operative device  20  further includes a driving device  634  comprised of an electromagnetic driver or the like. Driving device  634  includes a driving member  636  movable between an extended position and a retracted position. A draw bar  640  includes a tail  644  fixed to driving member  636  and a head  642  spaced from tail  644  along second axis Y. When driving device  634  is not electrified, driving member  636  and draw bar  640  are in the extended position ( FIG. 1 ). When driving device  634  is electrified, driving member  636  and draw bar  640  are moved to the retracted position ( FIG. 22 ). Draw bar  640  in the extended position has a spacing to latch  38  smaller than that in the retracted position. A substantially L-shaped attachment plate  638  extends outward from an outer periphery of driving device  634 . Two screws are extended through two fourth positioning holes  556  into attachment plate  638  to fix attachment plate  638 , such that driving device  634  is located in compartment  540  of casing  538 . 
     According to the form shown, operative device  20  further includes a follower plate  482  slideably mounted in first bracket  558  and third bracket  588 . Follower plate  482  includes two metal sheets fixed to each other by bonding or welding. Follower plate  482  includes front and rear ends  484  and  486  spaced along second axis Y. An extension  488  extends from an edge of follower plate  482  and is located between front and rear ends  484  and  486 . A stop  490  is formed on extension  488 . Follower plate  482  includes first and second grooves  492  and  494 . First groove  492  is located between second groove  494  and front end  484 . Second groove  494  is located between first groove  492  and rear end  486 . Extension  488  includes an elongated slot  496  parallel to first groove  492  and spaced from first groove  492  along third axis Z. Follower plate  482  further includes two insertion grooves  485  formed in a side of front end  484  and spaced along first axis X. Each insertion groove  485  is spaced from elongated slot  496  of extension  488  along second axis Y. A spacing between an end face of front end  484  and each insertion groove  485  along second axis Y is smaller than a spacing between the end face of front end  484  and elongated slot  496 . 
     Follower plate  482  is received between first and second plates  560  of first bracket  558  and between first and second walls  590  of third bracket  588 . A first spring  532  is mounted around a portion of follower plate  482  adjacent to extension  488  and between front and rear ends  484  and  486 . A first peg  628  is slideably received in first groove  492  of follower plate  482 . Front end  484  of follower plate  482  faces latch device  30 . Second end  734  of linking rod  730  is connected to front end  484  of follower plate  482 . Insertion blocks  752  of linking rod  730  are engaged in insertion grooves  485  of extension  488 . A connecting pin  497  is extended through front end  484  of follower plate  48  and hole  745  in second end  734  of linking rod  730 . Thus, linking rod  730  and follower plate  482  can move jointly. 
     According to the form shown, operative device  20  further includes a connecting member  498  slideably received in casing  538 . Connecting member  498  includes first and second plates  499  made of metal and spaced along first axis X. Connecting member  498  further includes a connecting plate  503  extending between intermediate portions of first and second plates  499 . A length of connecting plate  503  along second axis Y is smaller than that of each of first and second plates  499  along second axis Y. Each of first and second plates  499  includes first and second ends  500  and  502  spaced along second axis Y. Each of first and second plates  499  further includes a push slot  506  between first and second ends  500  and  502 . A hole  501  is defined in first end  500  of each of first and second plates  499 . A protrusion  504  is formed on the intermediate portion of each of first and second plates  499  and between first and second ends  500  and  502 . Protrusions  504  are aligned with connecting plate  503  and spaced from connecting plate  503  along third axis Z. 
     Rear end  486  of follower plate  482  is mounted between first and second plates  499  of connecting member  498 . Holes  501  of first and second plates  499  are aligned with first groove  492  of follower plate  482 . Second groove  494  of follower plate  482  is aligned with push slot  506  of connecting member  498 . First peg  628  received in first groove  492  is extended through holes  501  of first and second plates  499  of connecting member  498 , such that connecting member  498  can slide relative to follower plate  482  along second axis Y in a length extent of first groove  492  along second axis Y. First spring  532  is located between a side of protrusions  504 /connecting plate  503  and first groove  492  of follower plate  482 . A second spring  534  is mounted around first and second plates  499  of connecting member  498  and has an end abutting the other side of protrusions  504 /connecting plate  503 . A sleeve  508  is mounted around first and second plates  499  of connecting member  498  and has an end pressing against the other end of second spring  534 . A pin  510  is extended through sleeve  508  in a diametrical direction and through push slot  506  of connecting member  498  and through second groove  494  of follower plate  482 , such that sleeve  508  keeps pressing against the other end of second spring  534 . Furthermore, second spring  534  biases sleeve  508  such that pin  510  abuts against an end of push slot  506  adjacent to second ends  502  of first and second plates  499 . Since second spring  534  biases sleeve  508  and pin  510 , when connecting member  498  moves along second axis Y, pin  510  presses against an end wall of second groove  494  of follower plate  482 , causing joint movement of follower plate  482  and connecting member  498  along second axis Y. 
     According to the form shown, operative device  20  further includes a connecting rod  512  having a connecting end  514  and a pull end  516  spaced from connecting end  514  along second axis Y. Connecting rod  512  further includes a mounting hole  518 , two coupling holes  522 , and an engaging hole  520 . Coupling holes  522  are located between engaging hole  520  and mounting hole  518 . Mounting hole  518  is located between engaging holes  522  and connecting end  514 . Engaging hole  520  is located between coupling holes  522  and pull end  516 . Connecting rod  512  further includes two protrusions  523  on two lateral edges of an intermediate portion between connecting end  514  and pull end  516  of connecting rod  512 . Protrusions  523  are located between mounting hole  518  and coupling holes  522 . 
     In the form shown, connecting end  514  of connecting rod  512  is located between and welded to second ends  502  of first and second plates  499  of connecting member  498 , allowing joint movement of connecting rod  512  and connecting member  498  along second axis Y. Connecting rod  512  is received between first and second plates  560  of second bracket  558  and first and second walls  590  of third bracket  588 . First and second supports  524  are engaged on two opposite surfaces of connecting rod  512  and cover coupling holes  522 . A pressing block  526  is fixed to mounting hole  518  of connecting rod  512  such as by riveting. First and second stop boards  528  and  530  are mounted on connecting rod  512 . First stop board  528  abuts protrusions  523 . Second stop board  530  is engaged in insertion grooves  567  of second bracket  558  ( FIGS. 12 and 13 ). A third spring  536  is mounted between first and second stop boards  528  and  530  and around first and second supports  524 . Third spring  536  biases connecting rod  512  and connecting member  498  to move in the latching direction along second axis Y. First and second supports  524  avoid distortion of third spring  536  when compressed. 
     According to the form shown, operative device  20  further includes substantially U-shaped first and second traction members  650  pivotably mounted to first and second brackets  558 , respectively. Each of first and second traction members  650  includes first and second portions  652  spaced along first axis X and having substantially triangular cross sections. Each of first and second traction members  650  further includes a connecting portion  654  extending between first and second portions  652 . Each of first and second portions  652  of each of first and second traction members  650  includes spaced first, second, and third corners  655 ,  656 , and  658 . First traction member  650  is received between first and second plates  560  of first bracket  558 . Second traction member  650  is received between first and second plates  560  of second bracket  558 . First axle  616  is extended through third corner  658  of first traction member  650  and elongated slot  496  of follower plate  482 . Thus, first traction member  650  can pivot relative to first bracket  558  about a pivot axis defined by first axle  616  and parallel to the pivot axis defined by latch pin  42 . Second axle  618  is extended through third corner  658  of second traction member  650 . Thus, second traction member  650  can pivot relative to second bracket  558  about a pivot axis defined by second axle  618  and parallel to the pivot axis defined by first axle  616 . First peg  628  is extended through second corner  656  of first traction member  650 , pivotably connecting first traction member  650  to first ends  500  of first plates  499  of connecting member  498 . A second peg  632  is extended through second corner  656  of second traction member  650  and engaging hole  520  of connecting rod  512 , pivotably connecting second traction member  650  to connecting rod  512 . When first and second traction members  650  pivot, connecting rod  512  and connecting member  498  are pushed to move in the unlatching direction along second axis Y. 
     According to the form shown, operative device  20  further includes U-shaped first and second follower element  660  pivotably connected to first and second traction members  650 , respectively. Each of first and second follower elements  660  includes first and second plates  662  spaced along first axis X and a connecting plate  663  extending between first and second plates  662 . Each of first and second plates  662  includes first and second pivotal portions  664  and  666 . First and second portions  652  of first traction member  650  are received between first and second plates  662  of first follower element  660 . First and second portions  652  of second traction member  650  are received between first and second plates  662  of second follower element  660 . Each of two fourth axles  667  is extended through first pivotal portion  664  of one of first and second follower elements  660  and first corner  655  of one of first and second traction members  650 . Thus, first follower element  660  is pivotable relative to first traction member  650  about a pivot axis defined by one of fourth axles  667  and parallel to the pivot axis defined by latch pin  42 , and second follower element  660  is pivotable relative to second traction member  650  about a pivot axis defined by the other fourth axle  667  and parallel to the pivot axis defined by latch pin  42 . First pin  622  received in sliding slots  564  of first bracket  558  is extended through second pivotal portion  666  of first follower element  660 . Second pin  624  received in sliding slots  564  of second bracket  558  is extended through second pivotal portion  666  of second follower element  660 . Thus, first follower element  660  can cause pivotal movement of first traction member  650  while sliding in sliding slot  564  of first bracket  558  along third axis Z. Likewise, second follower element  660  can cause pivotal movement of second traction member  650  while sliding in sliding slot  564  of second bracket  558  along third axis Z. 
     According to the form shown, operative device  20  further includes a U-shaped stop member  668  pivotably mounted to third bracket  588 . Stop member  668  includes first and second walls  670  spaced along first axis X and a connecting wall  672  extending between first and second walls  670 . Each of first and second walls  670  includes first and second ends  674  and  676 . A notch  680  is defined in each of first and second walls  670  and located adjacent to second end  676 , and a face  682  is defined between second end  676  and notch  680 . A pivot hole  684  is defined in each of first and second walls  670  and located between notch  680  and first end  674 . A bend  678  extends from an edge of each of first and second walls  670  along first axis X. A stop block  686  is formed between first ends  674  of first and second walls  670 . 
     Stop member  668  is received between first and second walls  590  of third bracket  588 . Pivot holes  684  of stop member  668  are aligned with axle holes  595  of third bracket  588 . Third axle  620  is extended through pivot holes  684  of stop member  668 , such that stop member  668  can pivot about a pivot axis defined by third axle  620  and parallel to the pivot axis defined by latch pin  42 . Stop block  686  of stop member  668  faces stop  490  of follower plate  482 . Bends  678  abut the inner faces of first and second walls  590  of third bracket  588  to provide stable pivotal movement of stop member  668 . 
     According to the form shown, operative device  20  further includes a substantially U-shaped connecting element  649  fixed to head  642  of draw bar  640 . Connecting element  649  includes two arms having aligned pin holes  651  and an intermediate portion between the arms. Third pin  626  is extended through pin holes  651  of connecting member  649 . A third stop  648  is mounted between connecting member  649  and engagement tabs  598  of third bracket  588 . A fourth spring  646  is mounted around head  642  of draw bar  640  and between third stop  648  and the intermediate portion of connecting member  649 . When draw bar  640  is moved to the extended position, connecting member  649  moves third pin  626  into notches  680  of stop member  668 . When draw bar  640  is moved to the retracted position, connecting member  649  is moved in the unlatching direction along axis Y by draw bar  640  and compresses fourth spring  646 . Furthermore, connecting member  649  causes third pin  626  in notches  680  to push stop member  668  to pivot, such that stop block  686  abuts stop  490  of follower plate  482 . Third pin  626  moves to faces  682  of stop member  668 . Stop member  668  prevents follower plate  482  from moving in the unlatching direction along second axis Y. 
     According to the form shown, operative device  20  further includes an operative member  688  movably mounted on casing  538 . Operative member  688  includes a body  690  having U-shaped cross sections. Body  690  includes first and second walls  692  spaced along first axis X and a connecting wall  694  extending between first and second walls  692 . Body  690  includes two end faces  696  spaced along second axis Y and respectively formed by end faces of first and second walls  692  and connecting walls  694 . First and second walls  692  and connecting wall  694  together define a space  698  having an opening  700  spaced from connecting wall  694  by third axis Z. Space  698  extends from one of end faces  696  through the other end face  696 . A ridge  704  is formed on an outer face of a distal edge of each of first and second walls  692 . An insertion groove  702  is defined in the outer face of each of first and second walls  692  and located adjacent to connecting wall  694  and spaced from ridge  704  along third axis Z. 
     Body  690  is mounted in compartment  540  of casing  538  by moving body  690  along third axis Z. Opening  700  of body  690  faces ribs  544  of casing  538 . First and second walls  692  of body  690  are received in opening  542  of casing  538 . The spacing between ridges  704  of body  690  along first axis X is slightly larger than a height of opening  542  of casing  538  along first axis X, preventing body  690  from disengaging from casing  538  along third axis Z. Furthermore, a sum of a length of cover plate  546  along second axis Y and a length of operative member  688  along second axis Y is approximately the same as a length of casing  538  along second axis Y. Thus, cover plate  546  and body  690  seal compartment  540  of casing  538 . 
     According to the form shown, operative device  20  further includes a decorative plate  706  and first and second end caps  708 . Decorative plate  706  has substantially C-shaped cross sections. Each of first and second end caps  708  includes a first portion  710  having a sidewall  712 . Each of first and second end caps  708  further includes a second portion  714  extending from sidewall  712  of first portion  710  and having substantially I-shaped cross sections. Each second portion  714  includes top and bottom faces  716  and  718  spaced along third axis Z. A hook  722  extends outward from bottom face  718  of each second portion  714  along third axis Z and includes an insertion groove  724  extending from a face of hook  722  towards but spaced from the other face of hook  722  along second axis Y. Insertion groove  724  of each hook  722  is spaced from bottom face  718  of a corresponding second portion  714  along third axis Z and extends in a direction parallel to the unlatching direction. Insertion groove  724  of each of first and second end caps  708  faces driving device  634  (leftwards in  FIG. 1 ). Two through-holes  726  are defined in second portion  714  of each of first and second end caps  708  with hook  722  located between through-holes  726  along second axis Y. 
     Decorative plate  706  is fixed to connecting wall  694  of body  690  and includes two lateral edges engaged in insertion grooves  702  of body  690 . Decorative plate  706  provides an aesthetic appearance for body  690 . First and second end caps  708  are mounted in two ends of space  698 . Sidewalls  712  of first portions  710  of first and second end caps  708  abut end faces  696  of body  690 . Second portions  714  of first and second end caps  708  extend into space  698  of body  690 . Top faces  716  of second portions  714  face connecting wall  694  of body  690 . Hooks  722  of second portions  714  face opening  700  of body  690 . Screws are mounted in space  698  and extend through through-holes  726  of first and second end caps  708  into connecting wall  694  of body  690 . First and second pins  622  and  624  are inserted into insertion grooves  724  of hooks  722  of first and second end caps  708 . When body  690  is moved along third axis Z, first and second end caps  708  urge first and second pins  622  and  624  to move along third axis Z, driving first and second follower elements  660  to cause movement of connecting member  498  and connecting rod  512  in the unlatching direction along second axis Y. 
     Now that the basic construction of door lock  2  of the present invention has been explained, the operation and some of the advantages of door lock  2  can be set forth and appreciated. In particular, for the sake of explanation, it will be assumed that door  1  is not closed ( FIG. 8 ) and that latch  38  is in its extended, latching position. First ends  341  of first and second side boards  345  of swaying plate  34  are in the first, outer position outside of cover  315  under the action of spring  393  that presses against limiting block  35  fixed to swaying plate  34 . In this case, limiting block  35  is in the holding position holding locking member  36  in its upper, unlocking position ( FIG. 9 ), and wider section  369  of guide piece  364  of locking member  36  is received in second, smaller end  353  of guide groove  356  of limiting block  35 . Furthermore, guide grooves  363  of locking member  36  are aligned with extensions  323  of follower  32 . Further, linking rod  730  is in its first limit position ( FIG. 8 ). Specifically, protrusion  742  of linking rod  730  is aligned with but outside of groove  366  ( FIG. 11 ), and limiting pin  44  is in front end  746  of slot  744 . In this state, latch  38  can be pivoted from the latching position to the unlatching position. 
     When closing door  1 , third face  386  of latch  38  is pressed against by stop  12  and, thus, pivots inward. Follower  32  pivots inward together with latch  38  so that extensions  323  of follower  32  are extended through and engaged with guide grooves  363  of locking member  36 . Pivotal movement of follower  32  also causes movement of limiting pin  44  in the unlatching direction away from latch  38 , which, in turn, moves linking rod  730  in the unlatching direction away from latch  38  so that protrusion  742  of linking rod  730  is moved into and engaged with groove  366  of locking member  36 . Insertion blocks  752  of linking rod  730  push follower plate  482  to move in the unlatching direction along second axis Y and to compress first spring  532  ( FIG. 14 ). The displacement of follower  482  along second axis Y is smaller than the length of each of first and second grooves  492  and  494  and elongated slot  496 . Thus, first and second pegs  628  and  632  and pin  510  are not moved when follower plate  482  is moved by linking rod  730 . As a result, latch  38  is pressed by stop  12  and retracted. Furthermore, connecting member  498 , connecting rod  512 , first and second traction members  650 , first and second follower elements  660 , and operative member  688  are not moved. 
     Furthermore, first face  382  of latch  38  presses against drive pieces  344  of swaying plate  34  to make first ends  341  of first and second side boards  345  of swaying plate  34  pivot inward to the inner, second position, and limiting block  35  is moved to the releasing position. Specifically, guide groove  356  of limiting block  35  is moved to a position where second, smaller end  353  is aligned with and receives narrower section  365  of guide piece  364  of locking member  36 . Namely, locking member  36  is no longer restrained by limiting block  35  but is still held in the upper, unlocking position by protrusion  742  of linking rod  730 . Note that first, larger end  352  of guide groove  356  provides a space allowing passage of wider section  369  of guide piece  364  of locking member  36 . At this time, actuating plate  614  of switch  612  is pressed by pressing block  526  and forms an open circuit (not conductive). 
     When door  1  is completely closed, first ends  341  of first and second side boards  345  of swaying plate  1  are pressed against and retained in place by stop  12  in the inner, second position. Limiting block  35  is retained in the releasing position. Note that locking member  36  is no longer restrained by limiting block  35 , since the second, smaller end  353  of guide groove  356  is aligned with and receives narrower section  365  of guide piece  364  of locking member  36 . First spring  532  causes linking rod  730  to move in the latching direction along second axis Y, returning latch  38  to the latching position. Second face  385  of latch  38  presses against stop  12  to lock door  1 . Furthermore, linking rod  730  moves in the latching direction toward latch  38 , such that protrusion  742  of linking rod  730  disengages from groove  366  of locking member  36 . Thus, locking member  36  is released from protrusion  742  and moves downward along guide pin  43  (along first axis X) under the action of gravitational force to the lower, locking position resting on an inner face of second sidewall  331  ( FIG. 17 ). As a result, guide grooves  363  no longer align with extensions  323  of follower  32  (extensions  323  now abut front face  361  of locking member  36 ). Namely, when door  1  is completely closed, pivotal movement of latch  38  from the extended, latching position to the retracted, unlatching position is prevented, for the follower  32  that pivots together with latch  38  can not pivot inward due to the fact that extensions  323  of follower  32  are not aligned with and, thus, can not pivot into guide grooves  363  of locking member  36 . An anti-picking function is, thus, provided. In this case, protrusion  742  of linking rod  730  is not aligned with and outside of groove  366  of locking member  36 . Furthermore, protrusion  742  of linking rod  730  abuts against a wall portion of end opening  368  ( FIG. 16 ). 
     When opening of door  1  is desired, operative member  688  is pressed to an extent to cause pivotal movement of first and second follower elements  660 , which, in turn, moves linking rod  730  in the unlocking direction along second axis Y. Specifically, when operative member  688  is pressed, hooks  722  of first and second end caps  708  cause first and second pins  622  and  624  to slide towards connecting plates  562  along sliding slots  564  of first and second brackets  558  along third axis Z. First and second pins  622  and  624  respectively drive first and second traction members  650  to pivot about pivot axes defined by first and second axles  616  and  618 . Second corners  656  of first and second traction members  650  respectively push first and second pegs  628  and  632  to slide in the unlatching direction along second axis Y. First and second pegs  628  and  632  cause connecting member  498  and connecting rod  512  to move in the unlatching direction along second axis Y. During movement of connecting member  498 , second spring  534  urges sleeve  508  to move, causing movement of pin  510  that abuts an end wall of second groove  494 , which, in turn, causes follower plate  482  to move in the unlatching direction along second axis Y. Follower plate  482  draws linking rod  730  to move in the unlatching direction along second axis Y. Linking rod  730  moves through its idle travel equal to the length of slot  744  without moving limiting pin  44  and follower  32  ( FIGS. 14A and 18 ). During the idle travel of linking rod  730 , protrusion  742  of linking rod  730  moves through end opening  368  into groove  366  of locking member  36  ( FIG. 19 ) and moves locking member  36  upward along guide pin  43  to the upper, unlocking position so that guide grooves  363  of locking member  36  are aligned with extensions  323  of follower  32  (see  FIG. 9 ). Note that limiting pin  44  is now in front end  746  of slot  744  of linking rod  730 . When operative member  688  is further pressed, linking rod  730  moves further in the unlatching direction to move limiting pin  44  in the unlatching direction. As a result, latch  38  pivots together with follower  32  to the retracted, unlatching position allowing opening of door  1  ( FIGS. 20 and 21 ). At the same time, when latch  38  is in the retracted, unlatching position, first and second walls  692  of body  690  of operative member  688  abut pads  557  of mounting plate  548 . 
     When door  1  is in the closed state, door lock  2  can be switched to the locking state (by such as using a remote control). Driving member  636  of driving device  634  moves in the latching direction along second axis Y under action of electromagnetic force. Draw bar  640  is moved from the extended position ( FIG. 1 ) to the retracted position ( FIG. 22 ). Draw bar  640  moves connecting element  649 , causing second peg  632  to press against an end face of notch  680  of stop member  668  and to pivot stop member  668  about the pivot axis defined by third axle  620  until stop block  686  of stop member  668  abuts against stop  490  of follower plate  482  ( FIG. 22 ). Thus, follower plate  482  and linking rod  730  can not move in the unlatching direction along second axis Y, preventing latch  38  from pivoting to the unlatching position. Furthermore, burglarproof system  756  can be activated while door lock  2  is in the locking state. In this case, pressing block  526  presses against actuating plate  614  of switch  612 , such that switch  612  is not conductive and, thus, will not trigger the burglarproof system  756 . 
     When door  1  is in the closed state and draw bar  640  is in the retracted position ( FIG. 22 ), if operative member  688  is pressed (such as along third axis Z), operative member  688  causes first and second pins  622  and  624  to drive first and second traction members  650  to pivot about pivot axes defined by first and second axles  616  and  618 , such that first and second pegs  628  and  632  cause connecting member  498  and connecting rod  512  to move in the unlatching direction along second axis Y. At this time, movement of follower plate  482  in the unlatching direction along second axis Y is stopped by stop block  686  of stop member  668 . Due to the position of pin  510  stopped by the end wall of second groove  494 , movement of sleeve  508  in the unlatching direction along second axis Y is also stopped ( FIGS. 23 and 24 ). Thus, connecting member  498  and connecting rod  512  move idly along second axis Y without moving follower plate  482 . Furthermore, first groove  492  of follower plate  482  provides sufficient room for joint movement of first peg  628  with connecting rod  512  without moving follower plate  482 . During displacement of connecting rod  512 , pressing block  526  disengages from actuating plate  614  of switch  612 , such that switch  612  becomes conductive and activates the burglarproof system  756 . Displacement of connecting rod  512  also causes compression of second spring  534  by connecting plate  503  and protrusions  504 . Protrusions  523  of connecting rod  512  push first stop board  528  to compress third spring  536 . Thus, a resilient buffering effect is provided while operative member  688  is pressed. Furthermore, since follower plate  482  does not move in the unlatching direction along second axis Y, latch  38  will not pivot from the latching position to the unlatching position. Thus, when in the locking state, latch  38  will not retract when operative member  688  is pressed. When operative member  688  is released, second spring  534  returns connecting member  498 , and third spring  536  returns connecting rod  512 . 
     By providing connecting member  498  and connecting rod  512  movable relative to follower plate  482 , when door lock  2  is in the locking state, operative member  688  can still be pressed through an idle travel without unlatching latch  38  through the idle travel of connecting member  498  and connecting rod  512 . Second and third springs  534  and  536  provide a buffering effect when operative member  688  is pressed while door lock  2  is in the locking state, avoiding damage to the components of operative device  20 . 
     Furthermore, hooks  722  on first and second end caps  708  of operative member  688  reduces the time for assemblage of operative member  688 . Further, operative member  688  is comprised of fewer components to reduce to manufacturing costs. Further, insertion grooves  724  of operative member  688  extend in a direction parallel to the unlatching direction along second axis Y, such that first and second pins  622  and  624  can be reliably actuated when decorative plate  706  of operative member  688  is pressed without the risk of unreliable actuation and skew movement of operative member  688 . 
     Further, through engagement of connecting pin  497  of operative device  20  and linking rod  730  of latch device  30 , fast and separate repair or maintenance of operative device  20  and latch device  30  can be achieved. Specifically, since insertion blocks  752  of linking rod  730  are removably engaged in insertion grooves  485  of follower plate  482 , operative device  20  and latch device  30  can be disengaged from each other after removal of connecting pin  497 , allowing fast and separate repair or maintenance of operative device  20  and latch device  30 . 
     Now that the basic teachings of the present invention have been explained, many extensions and variations will be obvious to one having ordinary skill in the art. For example, latch device  30  does not have to include swaying plate  34 , limiting block  35 , locking member  36 , guide rod  39 , and spring  393 . Follower  32  does not have to include extensions  323 . Door lock  2  does not have to include casing  538  and mounting plate  548 . In this case, first, second, and third brackets  558  and  588  can be directly mounted to first side  1 A of door  1 , and operative member  688  can be mounted to first and second pins  622  and  624 . Further, door lock  2  does not have to include connecting element  649 , third pin  626 , and movement slots  594  of third bracket  588 . When door lock  2  does not include connecting member  649 , head  642  of draw bar  640  can be directly coupled to stop member  668 . When draw bar  640  is in the extended or retracted position, stop member  668  can be controlled to abut or disengage from stop  490  of follower plate  482  to control door lock  2  in the locking or unlocking state. Further, door lock  2  does not have to include fixing plate  604  and switch  612 . In this case, door lock  2  can not be electrically connected to burglarproof system  756 . However, when door lock  2  is in the locking state, detection of pressing of operative member  688  can be done to generate an alarm message while other functions of door lock  2  remains unaffected. 
     Furthermore, each of first and second brackets  558  can include only one plate  560 , and third bracket  588  can include only one wall  590 . Connecting member  498  can include only one plate  499 . 
     Thus since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.