Patent Publication Number: US-8113021-B2

Title: Door lock with an improved structure

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The invention relates to a door lock with an improved structure and in particular, to a door lock whose outer handle cannot be taken off when it is locked. 
     2. Related Art 
     The conventional door lock, as shown in  FIG. 6 , has a turning device on the outer side of the door. A circular spacer  91  is provided in the handle  93 . A limiting element  92  is disposed in the circular spacer  91 , with a protruding part  921  extending out of the circular spacer  91 . The limiting element  92  also has a connecting hole  922  therein for a connecting shaft (not shown) to go through. The handle  93  on the device has a concave hole  931 , through which one can see the protruding part  921 . By pressing tie protruding part  921 , one can take off the handle  93  from the turning device. 
     Any skilled person can easily see the protruding part  921  of the limiting element  92  in the circular spacer  91  from the concave hole  931  on the handle  93 . Using a simple tool to press the protruding part  921  outside the circular spacer  91 , the person can readily take the handle  93  on the outer side of the door off the turning device. Afterwards, by adjusting other components of the turning device, the person can easily unlock the door lock and enter the room. 
     It is thus imperative to provide a door lock whose handle  93  cannot be taken off when the turning device is locked. 
     SUMMARY OF THE INVENTION 
     An objective of the invention is to provide a door lock with an improved structure. Using a stopping part installed on the limiting element inside the circular spacer and a matching groove on one end of the lock core inside the lock, the protruding part of the limiting element still stays inside the concave hole of the handle when the door lock is locked. Therefore, one cannot take off the handle on the outer side of the door once it is locked, achieving a better anti-theft effect. 
     To achieve the above-mentioned objective, the invention includes: 
     a positioning base disposed on the outer side of a door, whose center has a through hole; 
     a hollow circular spacer, which is mounted from the inner side of the positioning base through its through hole and whose one end is pivotally connected to the inner side of the positioning base; 
     a limiting element vertically disposed inside the circular spacer oil the outer side of the positioning base, whose center has a connecting hole and whose one end has a protruding part extending out of the circular spacer for pressing, wherein a stopping part is disposed between the protruding part and tie connecting hole in the circular spacer, the limiting element is urged by an elastic element provided in the circular spacer on the end of the protruding part, and the circular spacer has space for the limiting element to displace along the pressing direction; 
     a connecting shaft, whose one end goes through the positioning base, is positioned in the circular spacer on the outer side of the positioning base, and extends out of the connecting hole of the limiting element, the diameter of the connecting hole being greater than the diameter of the connecting shaft; 
     a lock control device, which is disposed in the circular spacer inside the positioning base so that the connecting shaft also goes through the lock control device to control its lock state; and 
     a handle, which has a junction hole on one side for the connection with the circular spacer outside the positioning base and a concave hole in connection with the handle and for the protruding part to fall therein as a block at the position corresponding to the protruding part of the limiting element, wherein the handle is provided with a lock with a lock core whose one end allows the insertion and turning of a key and whose other end is formed inward with a groove on two opposite sides for the stopping part of the limiting element to fall into, and one end of the groove is also connected with the extended end of the connecting shaft so as to move it as the handle turns. 
     When the door lock is in the unlock state, the stopping part of the limiting element falls in the groove on the end of the lock with the lock core. Therefore, the limiting element can retreat into the circular spacer when the protruding part is pressed. 
     When the door lock is in the lock state, the stopping part of the limiting element has a displacement from the groove on the lock core. Therefore, the pressed protruding part of the limiting element cannot retreat into the circular spacer as it is blocked by the outer edge of the lock core. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will become more fully understood from the detailed description given herein below illustration only, and thus is not limitative of the present invention, and wherein: 
         FIG. 1  is a three-dimensional exploded view of the invention; 
         FIG. 2  is a cross-sectional view of the limiting element and the lock core in the unlock state according to the invention; 
         FIG. 3  is a cross-sectional view of the limiting element and the lock core in the lock state according to the invention; 
         FIG. 4  is a schematic view showing the positions of the connecting shaft and the rotator when the disclosed door lock is locked; 
         FIG. 5  is a schematic view showing the positions of the connecting shaft and the rotator when the disclosed door lock is unlocked; and 
         FIG. 6  is a cross-sectional view showing the structure of a conventional door lock. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings wherein the same references relate to the same elements. 
     The disclosed door lock with an improved structure has an inner turning device  1  inside a door and an outer turning device  2  outside the door. It further has a lock base  3  inside the door matching with the two turning devices  1 ,  2 . 
     The outer turning device  2  has a positioning base  21 , a hollow circular spacer  22 , a limiting element  26 , a connecting shaft  27 , a lock control device  28 , and a handle  4 . 
     The positioning base  21  is connected and fixed with the inner turning device  1 , and is disposed on the outer side of the door. Its center has a through hole  211 . In this embodiment, a first concave part  212  in connection with the through hole  211  is respectively formed on two opposite sides of the through hole  211  on the positioning base  21 . A protective cover  213  is screwed along the outer edge. Two ribs  214  in connected with the turning device  1  extend horizontally on the inner side. 
     The hollow circular spacer  22  has two hollow ends. It goes from the inner side of the positioning base  21  via the through hole  211  to the outside. One end of the circular spacer  22  is pivotally connected to the inner side of the positioning base  21 . In this embodiment, the circular spacer  22  is pivotally connected to one end of the positioning base  21 . Its two sides have a first concave part  212  and a second concave part  224  connecting to the positioning base  21 , respectively. One end of the circular spacer  22  on the inner side of the positioning base  21  is connected with a fixing element  23 . With several protruding parts  221  on both sides of the positioning base  21 , the positioning base  21  is positioned between the protruding parts  221  of the circular spacer  22  and the fixing element  23  and can rotate therein. A torsion spring  24  is provided between the fixing element  23  and the protruding parts  221  of the circular spacer  22  in the positioning base  21 . It urges against the inner side of the positioning base  21 , so that the circular spacer  22  can automatically resume its position during rotation. A driving element  25  goes through the fixing element  23  and is positioned on the end of the circular spacer  22  on the inner side of the positioning base  21 . The driving element  25  connects to the lock base  3  and controls its lock state. 
     The limiting element  26  is vertically disposed in the circular spacer  22  on the outer side of the positioning base  21 . Its center has a connecting hole  261  and a protruding part  262  extending out of the circular spacer  22 . The inner wall of the circular spacer  22  on the end opposite to the protruding part  262  of the limiting element  26  is formed with a hollow part  263 . When the protruding part  262  of the limiting element  26  is pressed by the user, its other end falls into the hollow part  263 . The limiting element  26  makes a displacement inside the circular spacer  22 . The end of the protruding part  262  of the limiting element  26  is urged by the elastic element  222  in the circular spacer  22 . In this embodiment, the limiting element  26  has an urging hole  264  below the protruding part  262 . The elastic element  222  is an elastic rod, whose one end goes through the urging hole  264  and urges against the protruding part  262 . The limiting element  26  further has a stopping part  265  between the protruding part  262  and the connecting hole  261 . The stopping part  265  protrudes toward the opening of the circular spacer  22  outside the positioning base  21 . 
     One end of the connecting shaft  27  goes through the positioning base  21  and is positioned in the circular spacer  22  outside the positioning base  21 . The other end of the connecting shaft  27  extends out of the connecting hole  261  of the limiting element  26 . The diameter of the connecting hole  261  is greater than the diameter of the connecting shaft  27 . In this embodiment, the end of the connecting shaft  27  in the circular spacer  22  has a stopping part  271  urging against the limiting element  26 . 
     The lock control device  28  is disposed in the circular spacer  22  inside the positioning base  21 . The connecting shaft  27  also goes through the lock control device  28  and controls its lock state. The lock control device  28  has a rotor  281  in the circular spacer  28 . Two opposite sides of the rotor  281  have a stopping block  281   a , respectively. The two opposite sides of its bottom are provided with an arc section  281   b  respectively. The arc section  281  is disposed in the circular spacer  22  corresponding to the stopping part  271  on one end of the connecting shaft  27 . When the connecting shaft  27  turns, its leads the two arc sections  281   b  of the rotor  281  so that the rotor  281  performs a reciprocal motion in the circular spacer  22  (as shown in  FIGS. 4 and 5 ). A compressible spring is inserted between the other end of the arc section  281   b  of the rotor  281  and the fixing element  23 , thereby positioning the rotor  281  inside the circular spacer  22 . The two stopping blocks  281   a  are mounted in the circular spacer  22  through the second concave parts  224  thereof. The bottoms of the two second concave parts  224  prevent the stopping blocks  281   a  of the rotor  281  to position the rotor  281 . When positioning, the two stopping parts  281   a  of the rotor  281  fall into the two first concave parts  212  of the positioning base  21 . The connecting shaft  27  leads the two stopping parts  281   a  of the rotor  281  to escape from or enter the two first concave parts  212  of the positioning base  21 , thereby controlling the relative rotation between the circular spacer  22  and the positioning base  21 . 
     One side of the handle  4  has a connecting hole  41  for the circular spacer  22  outside the positioning base  21  to connect. At the corresponding position of the protruding pact  262  of the limiting element  26 , the handle  4  has a concave hole  42  for the protruding part  262  to fall into. In this embodiment, the handle  4  is formed with a little circular hole  44  for one to press the protruding part  262  of the limiting element at the corresponding position of the concave hole  42 . A lock  5  with a lock core  51  is disposed in the handle  4 . The lock core  51  allows the insertion and turning of a key on one end. Two opposite sides of its other end are formed inward with a groove  511 , respectively, for the stopping part  265  of the limiting element  26  to fall into. One end of the groove  511  is connected with the extended end of the connecting shaft  27 . Moreover, the lock core  51  has a protruding mover  512  for moving and turning the connecting shaft  27  on two opposite sides near the groove  511 . 
     When the key is pulled out of the lock along a specific direction, the protruding part is restricted to block at the outer edge of the lock core. The handle thus cannot escape from the block when the protruding part is pressed. 
     The lock  5  is set to rotate in a specific direction. In this embodiment, only when the lock core  51  and the key are both in the horizontal direction can the key be pulled out of or inserted into the lock core  51 . When the key is inserted into the lock  5 , it brings the lock core  51  to change the direction of the grooves  511 . In this case, one can use an appropriate tool to press the protruding part  262  of the limiting element  26  through the little circular hole  44  on the handle  4 . Because the inner wall of the circular spacer  22  corresponding to the protruding part  262  has a hollow part  263  and the stopping part  265  of the limiting element  26  can slide in the groove  511  on the end of the lock core  51  of the lock  5 , the protruding part  226  of the limiting element  26  can retreat into the circular spacer  22  when the protruding part  262  is depressed. When the concave hole  42  of the handle escapes form the block as the protruding part  262  of the limiting element  26  retreats, the handle  4  can be readily taken off the circular spacer  22  ( FIG. 2 ). 
     When the key is pulled out of the lock  5  along a specific direction, the stopping part  265  of the limiting element  26  and the grooves  511  of the lock core  51  mismatch. When one presses the protruding part  262  of the limiting element  26 , the stopping part  265  is blocked by the outer edge of the lock core  51 . Therefore, the limiting element  26  cannot retreat along the pressing direction. The concave hole  42  on the handle  4  thus cannot escape from the block of the protruding part  262  of the limiting element. In this case, the handle cannot be taken off the circular spacer  22  ( FIG. 3 ). 
     A primary advantage of the invention is that the disclosed door lock structure determines whether to prevent the protruding part  262  of the limiting element  26  from leaving the concave hole  42  of the handle  4  according to whether the key is inserted into or pulled out of the lock. Therefore, one cannot readily take the handle  4  off the circular spacer  22 . This increases the difficult of unlocking using tools other than the right key, achieving a better anti-theft effect. 
     Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that tall within the true scope of the invention.