Vehicle door latch device with double action mechanism

Information

  • Patent Grant
  • 6406073
  • Patent Number
    6,406,073
  • Date Filed
    Wednesday, September 20, 2000
    24 years ago
  • Date Issued
    Tuesday, June 18, 2002
    22 years ago
Abstract
A vehicle door latch device comprises an open lever (24) for connection to an outside open handle (25), a lock lever (34) for connection to an inside lock button (36) through a rod (101), an over-center spring (42) for elastically keeping the lock lever (34) in one of an unlocked position (U) and a locked position (L), a double action mechanism (27) for connection to an inside open handle (28), and an antitheft mechanism (100) having an antitheft spring (105) with elasticity weaker than elasticity of the over-center spring (42). The antitheft spring (105) is arranged to be compressed without displacing the lock lever (34) from the locked position (L) to the unlocked position (U) when the rod (101) is moved in an unlocking direction by an illegal access while the lock lever (34) is being in the locked position (L).
Description




TECHNICAL FIELD




The present invention relates to a vehicle door latch device, and more particularly, to a vehicle door latch device with a double action mechanism.




PRIOR ART




German Patent DE 4,313,248 C2 discloses a double action mechanism (hereafter, referred to as a DA mechanism) provided in a door latch device for the purpose of improving the performance of crime prevention of the door latch device. The DA mechanism can be called an improved mechanism of a previously well known one-motion door opening mechanism. The conventional one-motion mechanism is approximately simultaneously capable of restoring the latch device from a locked state to an unlocked state and opening the door, when an inside open handle of the door is operated in a case where the door latch device is in the locked state.




On the contrary, the DA mechanism merely restores the latch device from the locked state to the unlocked state without opening the door, when the door-opening operation of the inside open handle is performed in the locked state. The DA mechanism opens the door in accordance with the door-opening actuation of the inside open handle only when the latch device is in the unlocked state. Accordingly, in order to open the locked door having a latch device with a DA mechanism by the inside open handle, both a first door-opening actuation of the inside open handle for restoring the latch device to the unlocked state from the locked state and a second door-opening actuation of the inside handle for releasing the latch device are necessary. Thus, the DA mechanism requires the double action of the inside open handle when opening the door, so that it can improve the performance of crime prevention of the door latch device.




In addition, in a door equipped with the latch device with the DA mechanism, an inside lock button which is provided on an inside surface of the door may be arranged such that it can be used only when switching the latch device from the unlocked state to the locked state. In other words, in some cases, the inside lock button has no function of switching the latch device from the locked state to the unlocked state. In such a case, the unlocking of the latch device is performed by the first door-opening actuation of the inside open handle. By removing the function of the unlocking operation from the inside lock button, the performance of crime prevention of the door can furthermore be improved. In order to remove the function of the unlocking operation from the inside lock button, in the prior art, the inside lock button in the locked position is hidden inside the fancy board or trim board of the door, so that the inside lock button cannot be picked by fingers.




The inside lock button in the locked position has a high performance of crime prevention against an illegal access from the outside since it is hidden in the fancy board, but the performance of crime prevention of the connecting portion between the inside lock button and the latch device provided in the inside space of the door remains as it has been in the prior art.




SUMMARY OF THE INVENTION




Accordingly, it is an object of the present invention to provide a latch device with a DA mechanism in which the performance of crime prevention of the connecting portion between the inside lock button and the lock lever of the latch device is improved.




In order to attain this object, in the present invention, an antitheft mechanism is provided between the inside lock button and the lock lever, which does not transmit the unlocking movement of the inside lock button to the lock lever.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a front view of a latch assembly of a vehicle door latch device according to the present invention;





FIG. 2

is a rear view of the latch assembly in an unlocked state;





FIG. 3

is a segmentary rear view of the latch assembly in a locked state;





FIG. 4

is a partially enlarged view of an open link of the latch assembly;





FIG. 5

is a side view of the latch assembly in the locked state;





FIG. 6

is a segmentary side view of the latch assembly in the unlocked ate;





FIG. 7

is a segmentary side view of the latch assembly in which an inner lever is slightly rotated in a door-opening direction by a first door-opening actuation of an inside open handle in

FIG. 5

;





FIG. 8

is a segmentary side view of the latch assembly in which the inner lever is completely rotated in the door-opening direction in

FIG. 7

;





FIG. 9

is a side view of a sub lock lever of the latch assembly;





FIG. 10

is a side view of the inner lever of the latch assembly;





FIG. 11

is a side view of a release lever of the latch assembly;





FIG. 12

is a side view of a slide link of the latch assembly;





FIG. 13

is a side view of an actuator lever of the latch assembly;





FIG. 14

is a side view of an intermediate lever of the latch assembly;





FIG. 15

is a side view showing a coupling mechanism between the latch assembly and an inside lock button in the locked state;





FIG. 16

is a side view showing the coupling mechanism in the unlocked state; and





FIG. 17

is a side view showing the coupling mechanism when receiving an illegal access.











DESCRIPTION OF THE PREFERRED EMBODIMENT




An embodiment of the present invention will be described by referring to drawings. The vehicle door latch device according to the present invention comprises a latch assembly


1


which is attached to a vehicle door (not shown), and a striker


2


which is fixed to a vehicle body (not shown). The latch assembly


1


comprises a latch


3


which is engaged with the striker


2


when the door is closed, and a ratchet


4


which holds the engagement of the latch


3


and the striker


2


. The latch


3


is rotatably received by a latch shaft


7


in an upper portion of a concave portion


6


formed in a front surface of a synthetic resin latch body


5


, and the ratchet


4


is rotatably received by a ratchet shaft


8


in a lower portion of the concave portion


6


.




The latch


3


is urged in the clockwise direction in

FIG. 1

by a spring force of a latch spring


9


. When the door is in an open position, the latch


3


is located in an unlatched position and is brought into contact with a damper


10


on the latch body


5


by the spring force of the spring


9


. The ratchet


4


is urged in the counterclockwise direction by a spring force of a ratchet spring


11


. The ratchet


4


is brought into contact with an unlatching portion


12


of the latch


3


when the door is in an open position. When the door moves from the open position toward a full-closed position, the striker


2


enters a horizontal passage


13


formed in the latch body


5


to be brought into contact with a U-shaped groove


14


of the latch


3


, thereby the latch


3


turns counterclockwise against the spring force of the latch spring


9


. When the latch


3


turns from the unlatched position to a half-latched position, the ratchet


4


is engaged with a first step


15


of the latch


3


and the door reaches a half-closed position. Furthermore, when the latch


3


reaches a full-latched position shown in

FIG. 1

, the ratchet


4


is engaged with a second step


16


of the latch


3


and the door is held in the full-closed position.




The ratchet


4


has a ratchet pin


18


which projects onto the rear side of the latch body


5


through an opening


17


of the latch body


5


.




To the rear portion of the latch body


5


, as shown in

FIG. 5

, a metal back plate


20


is attached. The back plate


20


comprises a parallel plate


21


which is substantially in parallel with the rear surface of the latch body


5


, and a bent plate


22


which is angled to extend rearward from the interior side edge of the parallel plate


21


. The rear side portion of the latch body


5


is formed with a horizontal bulged portion


23


(

FIG. 2

) which projects rearward from the rear of the latch body


5


. The horizontal passage


13


is defined by the space on the front side of the horizontal bulged portion


23


.




As shown in

FIG. 2

, at the rear side of the latch body


5


above the horizontal bulged portion


23


, an open lever


24


is rotatably attached by the latch shaft


7


. An outside open handle


25


of the door is connected to the exterior side portion of the open lever


24


. The interior side portion of the open lever


24


is formed with a contact portion


26


which is operatively connected to an inside open handle


28


of the door through a double action mechanism


27


(hereafter DA mechanism


27


) described later. The open lever


24


is urged in the clockwise direction in

FIG. 2

by a spring force of a spring


29


, and is turned counterclockwise by the door-opening actuation of the open handles


25


,


28


. An upper end of a vertically extending elongated open link


30


is connected to the exterior side portion of the open lever


24


by a pin


31


. The open link


30


is positioned on the exterior side with respect to the horizontal bulged portion


23


so that the open link


30


does not overlap with the horizontal bulged portion


23


in the back-and-forth direction of the latch body


5


. In the middle portion of the open link


30


, a notch


32


(

FIG. 6

) is formed. The upper edge of the notch


32


is formed with a horizontal contact surface


33


which is angled toward the latch body


5


.




At the rear side of the latch body


5


below the horizontal bulged portion


23


, a lock lever


34


is rotatably attached by the ratchet shaft


8


. The lock lever


34


has an exterior side portion which is connected to a key cylinder


35


of the door, and an interior side portion which is connected to an inside lock button


36


of the door through a coupling mechanism


200


including an antitheft mechanism


100


and a rod


101


. The configuration to be described later of the antitheft mechanism


100


is the feature of the present invention. The lock lever


34


has a diagonally downward extending arm


38


which is connected to a right end of an approximately horizontal connecting link


39


by a pin


40


. A left end of the connecting link


39


is connected to the lower end of the open link


30


by a pin


41


.




The lock lever


34


is displaceable between an unlocked position U shown in

FIG. 2 and a

locked position L shown in

FIG. 3

around the ratchet shaft


8


as a center by the actuation of one of the key cylinder


35


, the lock button


36


, and an actuator unit


37


described later. This displacement of the lock lever


34


makes the lower portion of the open link


30


move left and right around the pin


31


as a center, and the lock lever


34


is similarly displaced between the unlocked position U and the locked position L. The lock lever


34


(the open link


30


) is held by a spring force of an over-center spring


42


at one of the unlocked position U and the locked position L with respect to the dead point of the spring


42


as a boundary.




When the open link


30


is located at the unlocked position U as shown in

FIG. 2

, the horizontal contact surface


33


formed on the notch


32


is engageably opposed to the ratchet pin


18


in the vertical direction. Accordingly, the horizontal contact surface


33


is brought into contact with the ratchet pin


18


to turn the ratchet


4


clockwise in

FIG. 1

against the spring force of the ratchet spring


11


when the open link


30


is lowered by the actuation of the open lever


24


, thereby the latch


3


is released from the restriction by the ratchet


4


so as to open the door.




When the open link


30


is shifted to the locked position L by the locking actuation of the lock lever


34


, the horizontal contact surface


33


moves to the side of the ratchet pin


18


, as shown in

FIG. 3

, thereby the engageable state therebetween is cancelled. Accordingly, in the locked state of

FIG. 3

, the door cannot be opened even if the open link


30


is lowered.




As shown in

FIG. 5

, the actuator unit


37


is attached to the latch body


5


or the back plate


20


. The actuator unit


37


has an actuator shaft


48


which is outwardly projected from an actuator case


46


and which is rotated by the power of a built-in motor


47


.




Onto the bent plate


22


of the back plate


20


, an sub lock lever


52


(

FIG. 9

) is pivoted by a support shaft


51


which extends in the left-and-right direction of the latch body


5


. A hook


53


and a forked portion


54


are formed on the sub lock lever


52


. The forked portion


54


is engaged with the interior side portion of the lock lever


34


, so that the sub lock lever


52


and the lock lever


34


are displaced between the unlocked position U and the locked position L as one piece against the elasticity of the over-center spring


42


.




The coupling mechanism


200


for connecting the inside lock button


36


and the main lock lever


34


will be described. The antitheft mechanism


100


of the coupling mechanism


200


has, as shown in

FIG. 5

, an actuator lever or a lock side lever


49


(

FIG. 13

) which is fixed to an exposed end of the actuator shaft


48


, and an intermediate lever or a button side lever


102


(

FIG. 14

) which is rotatably supported by the actuator shaft


48


. The intermediate lever


102


can rotate independently from the actuator shaft


48


. The actuator lever


49


has at the tip end thereof a projection


50


engaged with the hook


53


of the sub lock lever


52


, so that the actuator lever


49


is displaceable integrally with the main lock lever


34


through the sub lock lever


52


. When rotating the actuator lever


49


fastened to the actuator shaft


48


by the power of the built-in motor


47


, the sub lock lever


52


and the main lock lever


34


are integrally displaced to the unlocked position U or the locked position L against the elasticity of the over-center spring


42


. One end of the intermediate lever


102


is connected to the inside lock button


36


through the rod


101


.




The actuator lever


49


has a projection


103


, and the intermediate lever


102


has a contact portion


104


with which the projection


103


can be engaged. An antitheft spring


105


is provided between the actuator lever


49


and the intermediate lever


102


. The elasticity of the antitheft spring


105


urges the intermediate lever


102


in the direction of the counterclockwise rotation (locking rotation) in

FIG. 5

, and urges the actuator lever


49


in the direction of the clockwise rotation (unlocking rotation). Consequently, usually, the projection


103


of the actuator lever


49


comes into contact with the contact portion


104


of the intermediate lever


102


. Here, it is important that the elasticity of the antitheft spring


105


should be weaker than the elasticity of the over-center spring


42


that keeps the lock lever


34


in either the unlocked position U or the locked position L.




In the locked state of

FIGS. 5 and 15

, when the actuator lever


49


is rotated clockwise by the unlocking actuation of the actuator unit


37


, the lock lever


34


is displaced to the unlocked position U through the sub lock lever


52


. At the same time, the projection


103


of the actuator lever


49


pushes the contact portion


104


of the intermediate lever


102


to rotate the intermediate lever


102


clockwise, and the inside lock button


36


is, as shown in

FIG. 16

, restored to the unlocked position U from the locked position L through the rod


101


. When the lock lever


34


is displaced to the unlocked position U from the locked position L by the unlocking actuation of the key cylinder


35


, the actuator lever


49


is rotated clockwise in FIG.


5


through the sub lock lever


52


, and then the projection


103


pushes the contact portion


104


to rotate the intermediate lever


102


clockwise, thereby the inside lock button


36


is restored to the unlocked position U from the locked position L.




Furthermore, in the unlocked state of

FIGS. 6 and 16

, when the actuator lever


49


is rotated counterclockwise by the locking actuation of the actuator unit


37


, the lock lever


34


is displaced to the locked position L through the sub lock lever


52


. At this moment, the projection


103


of the actuator lever


49


moves in the direction of being separated from the contact portion


104


, but the intermediate lever


102


is urged in the counterclockwise direction (locking direction) by the elasticity of the antitheft spring


105


, and therefore, the intermediate lever


102


is rotated counterclockwise following the movement of the actuator lever


49


, and thereby the inside lock button


36


is displaced to the locked position L from the unlocked position U as shown in FIG.


15


. When the lock lever


34


is displaced to the locked position L from the unlocked position U by the locking actuation of the key cylinder


35


, the rotation of the actuator lever


49


is similarly also transmitted to the intermediate lever


102


through the elasticity of the antitheft spring


105


, and the inside lock button


36


is then switched to the locked position L.




As mentioned above, in the switching of the device to the unlocked state U from the locked state, the rotation of the actuator lever


49


is directly transmitted to the intermediate lever


102


through the mechanical contact between the projection


103


and the contact portion


104


, but in the switching to the locked state from the unlocked state, the rotation of the actuator lever


49


is transmitted to the intermediate lever


102


through the elasticity of the antitheft spring


105


.




In the locked state of

FIGS. 5 and 15

, when any one of the inside lock button


36


, the rod


101


, and the intermediate lever


102


receives an illegal access for unlocking the device, the intermediate lever


102


is rotated clockwise, and then the unlocking rotational force of the intermediate lever


102


is transmitted to the actuator lever


49


through the antitheft spring


105


. But, the actuator lever


49


is held in the locked position L by the elasticity of the over-center spring


42


having an elasticity stronger than that of the antitheft spring


105


. Therefore, the antitheft spring


105


cannot rotate the actuator lever


49


from the locked position L to the unlocked position U and the antitheft spring


105


is merely compressed as shown in

FIG. 17

, even if the intermediate lever


102


is rotated in the unlocking direction by the illegal access. Thus the locked state of the latch assembly


1


is held. If the inside lock button


36


is displaced to the unlocked position U by the illegal access, it will be restored to the locked position L by the restoring force of the antitheft spring


105


after the latch assembly


1


is released from the illegal access.




Next, the double action mechanism


27


will be described. As shown in

FIG. 5

, the DA mechanism


27


is attached to the bent plate


22


, and is operatively provided among the inside open handle


28


and the open lever


24


and the lock lever


34


. The DA mechanism


27


makes the open lever


24


turn so as to open the door when the inside open handle


28


is operated while the lock lever


34


is located in the unlocked position U. However, if the inside handle


28


is operated to open the door while the lock lever


34


is located in the locked position L, the DA mechanism


27


does not open the door, but it shifts the lock lever


34


from the locked position L to the unlocked position U. That is, the DA mechanism


27


restores the lock lever


34


(and the inside lock button


36


) to the unlocked position U by a first door-opening actuation of the inside open handle


28


, and by a second door-opening actuation of the inside handle


28


, the DA mechanism


27


opens the door. The double action consisting of the first and second door-opening actuations required by the DA mechanism


27


improves the antitheft performance of the door latch device.




The structure of the DA mechanism


27


will be described in detail. The DA mechanism


27


has an inner lever


55


(

FIG. 10

) which is pivoted to the bent plate


22


by a mounting shaft


56


in parallel with the support shaft


51


and which is connected to the inside open handle


28


. When the inside handle


28


is not operated, the inner lever


55


is held at its initial position or rest position shown in

FIG. 5

by a spring (not shown) provided at the inside handle


28


. The inner lever


55


has a push arm


57


, a hook


58


, and a blocking surface


59


communicating with one end of the hook


58


. The push arm


57


is engageably opposed to an engaging projection


60


of the sub lock lever


52


positioned in the locked position L. The arm


57


is brought into contact with the engaging projection


60


to turn the sub lock lever


52


in the counterclockwise (unlocking) direction so as to displace the main lock lever


34


from the locked position L to the unlocked position U when the inner lever


55


is turned counterclockwise.




Onto the mounting shaft


56


, a release lever


61


(

FIG. 11

) is pivoted such that it may overlap with the inner lever


55


. The release lever


61


is urged in the clockwise direction in

FIG. 5

by a spring


68


, and is usually brought into contact with a stopper


69


attached to the bent plate


22


. The release lever


61


has a contact arm


62


, and an elongated hole


63


which partially overlaps with the hook


58


and which extends in the radial direction of the mounting shaft


56


. A slide pin


65


is slidably engaged with the elongated hole


63


. The slide pin


65


is formed at an upper end of a slide link


64


(

FIG. 12

) which extends in the vertical or up-and-down direction of the latch body


5


. The slide link


64


has, at the lower end thereof, a connecting pin


66


which is slidably engaged with a circular arc slot


67


formed on the sub lock lever


52


around the support shaft


51


as a center. Between the slide link


64


and the sub lock lever


52


, a spring


70


for urging the slide link


64


downward is provided. The spring


70


has a first leg engaged with connecting pin


66


and a second leg engaged with the sub lock lever


52


.




In the locked state of

FIG. 5

, the connecting pin


66


of the slide link


64


is brought into contact with a lower end


71


of the circular arc slot


67


by the elasticity of the spring


70


, and the slide pin


65


is positioned at the upper portion in the elongated hole


63


of the release lever


61


and is disengaged from the hook


58


of the inner lever


55


so as not to transmit the rotational movement of the inner lever


55


to the release lever


61


. This position of the slide link


64


where the slide pin


65


is disengaged from the hook


58


, is called a non-connective position.




In the above locked state, when unlocking the lock lever


34


by using the key cylinder


35


, the sub lock lever


52


is turned in the counterclockwise (unlocking) direction in FIG.


5


through the main lock lever


34


, and is then displaced to the unlocked position U as shown in FIG.


6


. In addition, since the connecting pin


66


is pressed against the lower end


71


of the slot


67


of the sub lock lever


52


by the spring force of the spring


70


, the slide link


64


is moved downward, following the unlocking movement of the sub lock lever


52


, and the slide pin


65


is then engaged with the hook


58


of the inner lever


55


, so that the slide pin


65


can transmit the rotational movement of the inner lever


55


to the release lever


61


. This position of the slide link


64


where the slide pin


65


is engaged with the hook


58


, is called a connective position.




To the mounting shaft


56


, a sub inner lever


72


is also pivoted. The sub inner lever


72


has, at one end thereof, a sub projection


73


which is engageable with the contact arm


62


of the release lever


61


, and has, at the other end thereof, an engaging portion


74


which is engageably opposed to the interior side portion of the open lever


24


. When the release lever


61


is turned counterclockwise, the contact arm


62


of the release lever


61


is brought into contact with the sub projection


73


of the sub inner lever


72


to turn the sub inner lever


72


counterclockwise. Then, the engaging portion


74


at the lower portion of the sub inner lever


72


is brought into contact with the interior side portion of the open lever


24


and turns the open lever


24


so as to open the door.




Between the sub inner lever


72


and the release lever


61


, a well known child-lock mechanism can be provided, if desired. It should be noted that the sub inner lever


72


could be integrally formed with the release lever


61


as one-piece when the child-lock mechanism is not necessary.




The operation of the DA mechanism


27


will now be explained. In the locked state of

FIG. 5

, even if turning the inner lever


55


counterclockwise by the first door-opening actuation of the inside open handle


28


, the release lever


61


is not turned due to the disengagement of the slide pin


65


from the hook


58


. Instead of that, by the rotational movement of the inner lever


55


, the blocking surface


59


of the inner lever


55


is shifted to overlap with the elongated hole


63


, and the push arm


57


of the inner lever


55


is brought into contact with the engaging projection


60


of the sub lock lever


52


to gradually turn the sub lock lever


52


counterclockwise. Thereby the main lock lever


34


is gradually displaced toward the unlocked position U from the locked position L by the engagement between the forked portion


54


of the sub lock lever


52


and the interior side end of the lock lever


34


against the elasticity of the over-center spring


42


, and the slide pin


65


of the slide link


64


which is moved downward together with the sub lock lever


52


is brought into contact with the blocking surface


59


of the inner lever


55


, as shown in FIG.


7


. It is noted that, in the state of

FIG. 7

, the main lock lever


34


has not yet been exceeded the dead point of the over-center spring


42


so that the main lock lever


34


and the sub lock lever


52


are still urged by the elasticity of the over-center spring


42


toward the locked position L. Therefore the main lock lever


34


, the slide pin


65


and so on are returned to the initial positions thereof shown in

FIG. 5

if the first door-opening actuation of the inside handle


28


is interrupted in the state of FIG.


7


.




In the state of

FIG. 7

, when further turning the inner lever


55


counterclockwise by the first door-opening actuation of the inside open handle


28


, the sub lock lever


52


is further pressed by the push arm


57


and the lock lever


34


is displaced to the unlocked position U as shown in

FIG. 8

, but the slide pin


65


is still in contact with the blocking surface


59


. The above rotational movement of the inner lever


55


by the first door-opening actuation is called an unlocking movement.




When the sub lock lever


52


is displaced from the locked position L to the unlocked position U by the first door-opening actuation of the inner lever


55


in the locked state, the actuator lever


49


of the antitheft mechanism


100


connected to the sub lock lever


52


is also rotated clockwise, and the projection


103


of the actuator lever


49


pushes the contact portion


104


of the intermediate lever


102


to rotate the intermediate lever


102


clockwise, and as shown in

FIG. 16

, the inside lock button


36


is restored from the locked position L to the unlocked position U through the rod


101


.




In the state of

FIG. 8

where the locked state is released, when interrupting the first door-opening actuation of the inside open handle


28


and restoring the inside handle


28


to the initial position, the inner lever


55


is turned clockwise, and the slide pin


65


is then released from the restriction by the blocking surface


59


, and thereby the pin


65


is moved downward by the elasticity of the spring


70


and is engaged with the hook


58


as shown in

FIG. 6

, and the door latch device becomes in the unlocked state.




In the unlocked state of

FIG. 6

, when turning the inner lever


55


counterclockwise by the second door-opening actuation of the inside open handle


28


, the release lever


61


is also turned counterclockwise by the engagement between the slide pin


65


and the hook


58


of the inner lever


55


, and thereby the contact arm


62


of the release lever


61


is brought into contact with the sub projection


73


of the sub inner lever


72


to turn the sub inner lever


72


counterclockwise. Then, the engaging portion


74


at the lower portion of the sub inner lever


72


is brought into contact with the interior side portion of the open lever


24


and turns the open lever


24


so as to open the door. The above rotational movement of the inner lever


55


by the second door-opening actuation is called an opening movement against the unlocking movement of the inner lever


55


in the locked state.




Advantages




As mentioned above, in the present invention, the locked state of the door latch device is prevented from being released, even when any one of the inside lock button


36


, the rod


101


, and the intermediate lever


102


receives the illegal access for unlocking.



Claims
  • 1. A vehicle door latch device comprising:an open lever for connection to an outside open handle of a vehicle door and arranged to open the door when the outside open handle is operated; a lock lever for connection to an inside lock button of the door through a rod and displaceable between an unlocked position where it makes a door-opening movement of the open lever effective and a locked position where it makes the door-opening movement of the open lever ineffective; an over-center spring for elastically keeping the lock lever in one of the unlocked position and the locked position; a double action mechanism for connection to an inside open handle of the door, said double action mechanism being arranged to switch the lock lever from the locked position to the unlocked position when the inside open handle is operated while the lock lever is being in the locked position, and further being arranged to actuate the open lever when the inside open handle is operated while the lock lever is being in the unlocked position; and an antitheft mechanism having an antitheft spring with elasticity weaker than elasticity of the over-center spring, said antitheft mechanism being provided between the rod and the lock lever; wherein said antitheft spring is arranged to be compressed without displacing the lock lever from the locked position to the unlocked position when the rod is moved in an unlocking direction by an illegal access while the lock lever is being in the locked position.
  • 2. The vehicle door latch device according to claim 1, wherein said antitheft spring is arranged to restore the rod, by the elasticity thereof, to an original position of the rod when the rod is released from the illegal access.
  • 3. The vehicle door latch device according to claim 1, wherein said antitheft mechanism includes a first lever which is displaced integrally with the lock lever and a second lever which is displaced integrally with the rod, and said antitheft spring includes a first leg portion engaged with the first lever and a second leg portion engaged with said second lever.
  • 4. The vehicle door latch device according to claim 3, wherein said first lever and said second lever are held in a state of being brought into contact with each other by the elasticity of the antitheft spring.
Priority Claims (1)
Number Date Country Kind
11-267182 Sep 1999 JP
US Referenced Citations (5)
Number Name Date Kind
5100185 Menke Mar 1992 A
5106135 Menke Apr 1992 A
5653484 Brackmann Aug 1997 A
5971449 Rogers Oct 1999 A
6343817 Watanabe Feb 2002 B1
Foreign Referenced Citations (1)
Number Date Country
43 13 248 Oct 1996 DE