Abstract:
A door lock and a door latch connecting device of a vehicle in which the portions for releasing the door latch are not exposed to the outside, thereby preventing a vehicular door from being opened by an abnormal method such as inserting a tool into the gap between the door belt and door glass.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a theft prevention feature and increased assemblage efficiency of a vehicle, and more particularly to a door lock and a door latch connecting device of a vehicle.  
         BACKGROUND OF THE INVENTION  
         [0002]    In general, once a driver steps out of the vehicle and locks the doors, the doors cannot be opened by mere manipulation of the outside door handles. A key must be used. The typical door lock includes a key cylinder mounted at a housing of the outside handle and a rotating lever secured at a rotor of the key cylinder. The rotating lever is connected to a door latch via a lock rod.  
           [0003]    Furthermore, the housing is generally mounted with a rotary arm that is moved downward in response to the pulling of the outside handle. The rotary arm is connected to the door latch via an unlock rod such that when the outside handle is pulled, the unlock rod moves downward to rotate a latch plate at the door latch. A striker mounted at the vehicular body is released from restriction to allow the door to be opened. When this occurs, the force of a torsion spring is restored, allowing the outside handle, the rotary arm, and the unlock rod to return to their original positions. When a user turns the key to rotate the rotating lever and raise the lock rod, the latch plate does not rotate even though the unlock rod is lowered by the internal structure of the door latch. In use, when the door is locked, the door is not opened even though the outside handle is manipulated while the lock rod is lifted.  
           [0004]    However, it is a well-known fact that an insertion of a long thin steel plate of about 3-5 cm width into a gap between a door belt and a door glass can be used to push an inner lock rod and release a locked door. Thus, resulting in frequent occurrences of vehicle theft. This abnormal unlocking method is possible because when the long thin steel plate presses the lock rod, the lock rod is lowered to return to its original position where the outside handle operates to lower the unlock rod causing the door to unlock without the use of a key.  
           [0005]    In order to prevent the door from being opened in the aforementioned abnormal method, a protective cover has been disclosed in the related art. The protective cover is commonly installed at an upper side of the cylinder for blocking the insertion route of a door lock releasing steel plate. However, the protective cover cannot be formed in a large enough size to completely block the insertion route because of the lay-out of the internal door devices. Thus, this design does not provide sufficient theft protection.  
           [0006]    A further current device consists of a clip, which stably connects the lock rod to the rotating lever. The head of the clip is inserted into a hole formed at the rotating lever. The end of the lock rod is formed into the clip such that when the clip is push-fitted into the hole the lock rod can rotate the clip. Furthermore, the lock rod is inserted between the body of the clip and a holder, such that a stable connection is made between the lock rod and the rotating lever.  
           [0007]    However, a drawback of using the clip design lies in the assembly work required for the design. The assembly work must be performed in a cramped narrow space in a door, thereby curtailing efficiency of assembly.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention provides a door lock and a door latch connecting device of a vehicle adapted to prevent the door lock from being released by a method, such as inserting theft tools like long thin steel plates, and the like into the gap between the door belt and door glass, thereby improving theft-prevention. Further, the present invention expedites the assembly for connecting the door lock and door latch in a manufacturing assembly line.  
           [0009]    According to an embodiment of the present invention, the door lock and the door latch connecting device comprises a cable connected at one end thereof to a door latch. An operation force switching means is connected to the other end of the cable for switching a rotary movement of a door lock to a linear movement of the cable. Further, a tube is provided for encompassing the cable for slidable movement and to shut off the cable from the outside. In use, the door lock and the door latch are connected by the cable wrapped by the tube, thereby preventing the locked state of the door lock from being released by a tool such as a long thin steel plate, or the like.  
           [0010]    There is another advantage in that it is very easy to connect a connecting device to the door lock thereby improving the assembly process. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    For fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings in which:  
         [0012]    [0012]FIG. 1 is an exploded perspective view of elements comprising a door lock and a door latch connecting device according to an embodiment of the present invention;  
         [0013]    [0013]FIG. 2 is an enlarged view of each part of the pulley illustrated in FIG. 1;  
         [0014]    [0014]FIG. 3 is an enlarged view of a cable and the tube in FIG. 1;  
         [0015]    [0015]FIG. 4 is an enlarged view of the protective cap in FIG. 1;  
         [0016]    [0016]FIG. 5 is a schematic drawing illustrating an assembled state of the pulley, the cable, and the protective cap to which a key cylinder of the door lock is attached; and  
         [0017]    [0017]FIG. 6 is a schematic drawing of a spline connecting structure of a pulley and a rotor. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.  
         [0019]    [0019]FIG. 1 shows the door lock and the door latch connecting device according to an embodiment of the present invention. The door lock includes a cable  71  connected at one end to a door latch (not shown). Also included is an operation force switching means connected to the other end of the cable  71  for switching the rotary movement of a door lock to a linear movement of the cable  71 . Furthermore, a tube  72  is disclosed for encompassing the cable  71  for slidable movement and to shut off the cable  71  from the outside.  
         [0020]    The operation force switching means includes a pulley  60  (FIG. 2) formed with a hitching groove  62  into which a hitching block  74  (FIG. 3) is mounted. The hitching block (FIG. 3) is coupled to the opposite end of the cable  71  from the door latch (not shown). A cable groove  61  (not shown) is provided for receiving and winding the cable  71  during a turning effect from a rotor  22  at the door lock. Also, FIG. 1 shows a protective cap  80  for encompassing an external side of the pulley  60  is provided to prevent the cable  71 , wound on the cable groove  61 , from being bent and also for encompassing the rotor  22  at the door lock from the outside.  
         [0021]    The pulley  60  and the rotor  22  are coupled, such that the turning effect of the rotor  22  can be transmitted to the pulley  60 . In use, by way of example and not limitation, a square groove  64  (FIG. 2) is formed at the pulley. The rotor  22  is formed in a matching square pillar shape to allow the rotor  22  (FIG. 1) to be inserted into the square groove  64  (FIG. 2), thereby enabling the transmission of the turning effect of the rotor  22  to the pulley  60 . In an alternative embodiment of the invention, the coupled structure of the pulley  60  and the rotor  22  are accomplished by a spline  66  (FIG. 6).  
         [0022]    [0022]FIG. 4 shows the protective cap  80  integrally formed with a rotary axle  81   a  for receiving the pulley  60  (FIG. 2). In an embodiment the rotary axle  81   a  is formed with a stepped portion. When the pulley  60  is inserted into the rotary axle  81   a  via a central hole  63 , the lateral surface of the pulley  60  does not directly contact an inner side of the protective cap  80 . Once the pulley  60  (FIG. 2) is inserted into the rotary axle  81   a , the inserted state of the pulley  60  is maintained by a snap spring  90 , (FIG. 1).  
         [0023]    [0023]FIG. 5 shows the protective cap  80  formed to be inserted onto an external side of a key cylinder at the door lock in order to encompass the rotor  22  of the door lock. The key cylinder  21  is provided with a plurality of protruding jaws  24  for securing the protective cap  80 . The protective cap  80  is formed with insertion holes  81   c  into which the protruding jaws  24  are inserted. The protective cap  80  can be secured at an external side of the key cylinder  21  at the door lock without using extra tools.  
         [0024]    [0024]FIG. 3 shows the tube  72  integrally mounted at an end with a bush  73 . The bush  73  is formed at a circumferential surface with a fixation groove  73   a.    
         [0025]    [0025]FIG. 4 shows the protective cap  80  is formed with a tube fixation portion  82  to receive the fixation groove  73   a  of the bush. While the tube fixation portion  82  is formed with a detachment preventing protruder  82   a  for preventing the bush  73  from being detached from the protective cap  80 , the detachment preventing protruder  82   a  is sized such that the bush  73  can be easily inserted, and the inserted state can be stably maintained.  
         [0026]    Hereinafter, a description will be made on how each part is assembled.  
         [0027]    The cable  71  (FIG. 1) is wound on the cable groove  61  (FIG. 2) of the pulley  60  and the hitching block  74  (FIG. 3) is press-fitted into the hitching groove  62  (FIG. 2).  
         [0028]    Under the above state, the fixation groove  73   a  of the bush  73  (FIG. 3) mounted at an end of the tube is inserted into the tube fixation portion  82  (FIG. 4) of the protective cap  80 . Simultaneously, the pulley  60  (FIG. 1) is inserted into the protective cap  80  such that a central hole  63  (FIG. 2) can be fitted to the rotary axle  81   a  (FIG. 4).  
         [0029]    The pulley  60  is prevented from contacting the internal surface of the protective cap  80  by the stepped rotary axle  81   a  (FIG. 4). The spaced state, at a predetermined amount, functions to reduce friction during operation.  
         [0030]    [0030]FIG. 5 shows the pulley  60 , the cable  71 , and the protective cap  80  all assembled. The plurality of protruding jaws  24  at the key cylinder are inserted into the insertion holes  81   c  by, for exampe, press-fitting operation of the protective cap  80  toward the key cylinder  21 , thereby completing the assembly work. The square pillar-shaped rotor  22  is then fitted into the square groove  64  in order to transmit the turning effect.  
         [0031]    In use, when a key is inserted into the key cylinder  21  and turned, the pulley  60  (not shown) is rotated in cooperation with the rotor  22 . The cable  71  is wound up by the hitching block  74 , FIG. 3, being in contact with the hitching groove  60  (FIG. 2) of the pulley  60 .  
         [0032]    The cable  71  is connected at one end to the door latch (not shown), such that the winding-up of the cable  71  exercises the unlocking of a door. Thereby, preventing the door from being opened by the simple manipulation of the handle  11  outside of the vehicle.  
         [0033]    When a key is inserted and turned while the door is locked as described above, the pulley  60  is rotated to the left to unwind the wound cable  71 , which inserts the cable  71  into the tube  72 , FIG. 1. Thereby, enabling a user to open the door by the manipulation of the handle  11  outside of the vehicle.  
         [0034]    Although the cable  71 , FIG. 1) is flexible, the cable  71  is prevented from being bent by restriction of the protective cap  80  and the cable groove  61  at the pulley. The cable  71  is lowered while being disposed inside the tube  72 , and the cable  71  pushed out from the bush  73  is not lengthy such that the manipulating power of the cable  71  can be sufficiently transmitted lengthwise.  
         [0035]    The tube  72  protects the cable  71 , FIG. 1, which is the real actuaor force transmitting medium for locking and unlocking the door. The tube  72  has nothing to do with the locking or unlocking operation of the door lock, such that the door cannot be opened by the conventional abnormal method, thereby reducing car thefts. In use, the tube  72  in the present invention cannot be hitched by a tool having a hooked end to unlatch the latch. Although the tube  72  was hitched and pulled up by such a tool, only a slight deformation results to the tube  72  and the cable  71 . Thus, the end of the cable  71  at the door latch (not shown) side cannot be pulled to the inside of the bush  73 , thereby preventing the door lock from being unlocked and increasing the vehicle safety from car theft.  
         [0036]    The protective cap  80 , where the pulley  60  and the cable assembly  70  are mounted, is simple in assembly because only the protective cap  80  needs to be inserted into the key cylinder  21  (FIG. 5). Thus, it is relatively easy to perform a mounting operation.  
         [0037]    The foregoing descriptions of specific embodiments of the present invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.