Patent Publication Number: US-2022235588-A1

Title: Door latch device

Description:
FIELD 
     The present invention relates to a door latch device for closing and opening a vehicle door. 
     BACKGROUND 
     A door latch device of a vehicle includes a latch mechanism that latches and unlatches a striker disposed on a main body side of the vehicle, and closes and opens a door by the latch mechanism. 
     Patent Literature 1 discloses a door latch device including an electric release mechanism that can release engagement between a latch mechanism and a striker by power of a motor, a manual release mechanism that can release engagement of the latch mechanism by manual operation force, and a lock mechanism that can switch between a locked state that disables a release function of the manual release mechanism and an unlocked state that enables the same. 
     In this door latch device, engagement of the latch mechanism is released exclusively by the electric release mechanism, and the manual release mechanism is disposed as a complement for a case in which the function of the electric release mechanism is disabled due to an accident, a fault in an electrical system, a voltage drop of a battery, and the like. Thus, the lock mechanism is used only for the function of the manual release mechanism, and is always used in the locked state and switched to the unlocked state for a predetermined situation. 
     In this door latch device, the locked state and the unlocked state of the lock mechanism are switched by normal rotation and reverse rotation of a cam wheel rotated by power of the motor. The cam wheel is held at a reference position by energizing force of a neutral return spring, and has a configuration for switching the lock mechanism to the locked state when normally rotated from the reference position, and switching the lock mechanism to the unlocked state when reversely rotated from the reference position. 
     Additionally, the cam wheel also releases engagement of the latch mechanism when normally rotated from the reference position. Line to this, the lock mechanism can be switched, and the engagement of the latch mechanism can be released by a single motor. 
     On the other hand, some door latch devices for closing and opening the vehicle door include electric components such as a motor and a position switch (refer to Patent Literature 2). The position switch is set to detect an operation of a predetermined object to be detected, and detects whether a component of the lock mechanism is at a position indicating the locked state or a position indicating the unlocked state, for example. A detection signal of the position switch is supplied to a predetermined circuit board, and control based thereon is performed. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Patent No. 6213927 
     Patent Literature 2: Japanese Laid-open Patent Publication No. 2018-12967 
     SUMMARY 
     Technical Problem 
     In the door latch device disclosed in Patent Literature 1 of what is called a knob-less type not including a locking/unlocking knob for manually switching the lock mechanism, manual switching to an unlocked state using a key and switching to the unlocked state by power of the motor are not required to be used unless a predetermined situation is caused. Thus, the lock mechanism does not work by a normal operation, and is maintained in the locked state for a long time. As a result, there is the concern that grease is hardened due to long-term deterioration, or a spring, a lever, and the like made of steel material rust, and the lock mechanism does not smoothly function in a predetermined situation. Thus, there is a demand for a door latch device in which the lock mechanism smoothly functions in a predetermined situation. 
     In the door latch device disclosed in Patent Literature 1, the lock mechanism is switched from the unlocked state to the locked state on the condition that engagement of the latch mechanism is released, so that the lock mechanism cannot be singly switched from the unlocked state to the locked state without releasing engagement of the latch mechanism by a single motor. Thus, there is a demand for a door latch device that can release engagement of the latch mechanism and switch the lock mechanism to the locked state and the unlocked state by a single motor. At this point, it is preferable that unnecessary sound that bothers a user is not generated. 
     On the other hand, an operation of the object to be detected is detected by the position switch, the detection signal read by a CPU, and control based on the detection signal performed. If the position switch breaks down, the operation of the object to be detected cannot be detected, so that there is the inconvenience that control related thereto is not performed. 
     The present invention is made in view of the problem described above, and provides a door latch device that can detect an operation of an object to be detected more securely. 
     Solution to Problem 
     To solve the above-described problem and achieve the object, a door latch device according to the present invention includes: a first posit on switch and a second position switch, each of the first position switch and the second position switch including a first contact hole connected to one of a normally open contact or a normally closed contact, a second contact hole connected to a contact having a reverse format of the first contact hole, and a common contact hole connected to a common contact, wherein the first contact hole, the second contact hole and the common contact hole are arranged on a straight line, the first position switch and the second position switch are disposed at positions shifted from each other along the straight line and stacked in a piercing direction of the first contact hole, the second contact hole, and the common contact; a common pin configured to be electrically conducted to the common contact hole of the first position switch and the first contact hole of the second position switch by being inserted therein; a first signal pin configured to be electrically conducted to the first contact hole of the first position switch by being inserted therein; and a second signal pin configured to be electrically conducted to the common contact of the second position switch by being inserted therein, wherein the first position switch and the second position switch are configured to perform a switch operation at a same timing of an operation of a predetermined operation detection target. 
     The door latch device may include a circuit board, and each of the common pin, the first signal n and the second signal pin may be erected from the circuit board. 
     A space in which the circuit board may be disposed and a space in which the: first position switch and the second position switch are disposed are partitioned with a partition plate, and the first signal pin, the second signal pin and the common pin may be configured to pierce pin holes formed on the partition plate and project from one of the spaces to another one of the spaces. 
     In the space in which the circuit board is disposed, waterproof treatment may be, applied to the: space in which the first position switch and the second position switch are: disposed, around the pin holes. 
     The operation detection target may include a first cam configured to act on an actuator of the first position switch, and a second cam configured to act on an actuator of the second position switch, and the first cam and the second cam may be shifted from each other in a stacking direction of the first position switch and the second position switch, and be disposed at positions shifted from each other along the: straight line. 
     The door latch device may includes a latch mechanism configured to hold a door of a vehicle in a closed state; an electric release unit configured to release the latch mechanism by power of a motor; a manual release unit configured to release the latch mechanism by manual operation force; and a lock mechanism configured to switch between a locked state for disabling a function of the manual release unit and an unlocked state for enabling the same, and the operation detection target may be a component whose position is switched depending on whether the lock mechanism is in the locked state or the unlocked state, and the first position switch and the second position switch may be configured to detect whether the operation detection target is in the locked state or the 
     Advantageous Effects of Invention 
     With the door latch device according to the present invention, the operation of the object to be detected is read twice by a stacked first position switch and second position switch, and the operation thereof can be detected more securely. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a door latch device according to an embodiment viewed from obliquely rearward on the outside of a vehicle. 
         FIG. 2  is a perspective view of the door latch device viewed from obliquely forward on the outside of the vehicle. 
         FIG. 3  is a side view illustrating an inner part of the door latch device. 
         FIG. 4  is a perspective view of a latch mechanism. 
         FIG. 5  is a perspective view of the lock mechanism viewed from obliquely inside rearward. 
         FIG. 6  is a perspective view of the lock mechanism viewed from obliquely outside forward. 
         FIG. 7  is a diagram for explaininq an operation of the lock mechanism at the time when a cam wheel normally rotates, (a) is a diagram illustrating a basic state in which the cam wheel is at a reference position, (b) is a diagram illustrating a state in which the cam wheel normally and slightly rotates from the reference position, (c) is a diagram illustrating a state in which the cam wheel normally rotates from the reference position by about 40°, (d) is a diagram illustrating a state in which the cam wheel normally rotates from the reference position by about 90°, (e) is a diagram illustrating a state in which the cam wheel normally rotates from the reference position by about 190° and (f) is a diagram illustrating a state in which the cam wheel normally rotates from the reference position by about 250°). 
         FIG. 8  is a diagram for explaining the operation of the lock mechanism at the time when the cam wheel reversely rotates and normally rotates, (a) is a diagram illustrating a basic state in which the cam wheel is at the reference position, (b) is a diagram illustrating a state in which the cam wheel reversely rotates from the reference position by about 40°, (c) is a diagram illustrating a state in which the cam wheel normally rotates from the state of (b) by about 40°, and (d) is a diagram illustrating a state in which the cam wheel normally rotates from the state of (c) by about 40°. 
         FIG. 9  is an exploded perspective view of electric components, components that house the electric components, and the like viewed from obliquely forward outside. 
         FIG. 10  is an exploded perspective view of electric components, components that house the electric components, and the like viewed from obliquely forward inside. 
         FIG. 11  is a circuit diagram to which a first switch and a second switch are applied in the door latch device. 
         FIG. 12  is a perspective view of the first switch. 
         FIG. 13  is an exploded perspective view of the first switch, the second switch, and a case. 
         FIG. 14  is a partial cross-sectional side view of the first switch and the second switch a state of being stacked and assembled, and the periphery thereof. 
         FIG. 15  is a perspective view illustrating the first switch, the second switch, and the periphery thereof inside the door latch device. 
         FIG. 16  is a diagram illustrating an operational relation among the first switch, the second switch, and a sub-lock lever, (a) is a diagram illustrating the sub-lock lever in a state of a locked attitude, and (b) is a diagram illustrating the sub-lock lever in a state of an unlocked attitude. 
         FIG. 17  is a circuit diagram according to a modification to which the first switch and the second switch are applied. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following describes an embodiment of a door latch device according to the present invention in detail based on the drawings. The present invention is not limited to the embodiment. 
     In the following description, representation of directions in the description of a door latch device  10  is based on the vehicle. As the directions based on the vehicle, upward and downward, inward and outward (that is, an indoor side and an outdoor side), and forward and rearward are indicated by arrows when appropriate in the drawings. Representation of a rotation direction (a clockwise direction, a counterclockwise direction) of a rotary component basically corresponds to the drawing that is referred to at the present point. The door latch device  10  exemplified in each of the drawings is a door latch device applied to a right side door of the vehicle, but a door latch device applied to a left side door may have a symmetrical structure. 
       FIG. 1  is a perspective view of the door latch device  10  according to the present embodiment viewed from obliquely rearward, and  FIG. 2  is a perspective view of the door latch device  10  viewed from obliquely forward on the outside of the vehicle. 
     The door latch device  10  is attached to an inner part of the door of the vehicle, and closes and opens the door by latching and unlatching a striker disposed on a main body side of the vehicle. For example, the door latch device  10  is disposed to latch the striker on a side door of the vehicle, but the “door” has a broad sense, and may be applied to a hood, a trunk lid, a tail gate, and the like. First, the following describes a schematic entire configuration of the door latch device  10 . 
     As illustrated in  FIG. 1  and  FIG. 2 , in the door latch device  10 , a latch  12  that latches the striker is disposed at the back of a striker entry groove  14 . The latch  12  is part of a latch mechanism  44  described later. The striker entry groove  14  is formed as part of a cover plate  16 . A body  18  is disposed around the cover plate  16 . An inner side and a rear side of the latch mechanism  44  are covered by the cover plate  16  and the body  18 . 
     The door latch device  10  is covered by a case  20 , a first cover  22 , and a second cover  24  in addition to the cover plate  16  and the body  18  described above. The, case  20  mainly covers an outer side, the, first cover  22  mainly covers an inner side, and the second cover  24  further covers a forward upper part of the inner side of the case  20 . The cover plate  16 , the body  18 , the case  20 , the first cover  22 , and the second cover  24  form a housing of the door latch device  10 . 
     The door latch device  10  further includes a waterproof cover  26  that covers an upper surface, a cable cover  28  on an inner lower side, a coupler  30  disposed on an inner upper part, and a key cylinder coupling part  32  disposed on an outer upper part The waterproof cover  26  covers a boundary part between the case  20  and the first cover  22 , and the second cover  24  from above to prevent entry of waterdrops. The cable cover  28  covers a connecting portion for a cable  35 . The cable  35  is connected to an inner handle (not illustrated). A harness connector (not illustrated) is connected to the coupler  30 . A sponge may be disposed around the coupler  30 . The key cylinder coupling part  32  is a portion into which a key is inserted to be operated. An end part of an outer lever  34  connected to an outer handle (not illustrated) is exposed to an outer surface of the door latch device  10 . 
       FIG. 3  is a side view illustrating an inner part of the door latch device  10 .  FIG. 3  illustrates the door latch device  10  in a state in which the body  18 , the first cover  22 , the waterproof cover  26 , and the cable cover  28  are removed. 
     As illustrated in  FIG. 3 , a first housing space  36  is formed inside the door latch device  10 . The first housing space  36  is a region the outer side of which is covered by the case  20 , and the inner side thereof is mainly covered by the first cover  22 . The inner side of the first housing space  36  is covered by the cover plate  16 , the body  18 , and the cable cover  28  in addition to the first cover  22 . 
     The first housing space  36  can be briefly partitioned into a mechanism region  40  in which a machine mechanism  38  is disposed, and an electric component region  42  in which electric components are disposed. The electric component region  42  occupies a forward upper part, and the mechanism region  40  occupies a remaining portion. The machine mechanism  38  includes a latch mechanism  44  that latches and unlatches the striker with the latch  12 , and a lock mechanism  46  that causes the latch mechanism  44  to be in a locked state and an unlocked state. The latch mechanism  44  is disposed rearward in the first housing space  36 , and covered by the cover plate  16  and the body  18 . In the door latch device  10 , a second housing space  124  (refer to  FIG. 10 ) is formed in addition to the first housing space  36 . The second housing space  124  will be described later. 
     The machine mechanism  38  also includes an electric release unit that can release the latch mechanism  44  by power of a motor  94 , and a manual release unit that can release the latch mechanism  44  by manual operation force. The electric release unit is a unit that includes the motor  94 , a cam wheel  76 , and the like (described later) , and unlatches the striker. The manual release unit is a unit that unlatches the striker via the outer lever  34  that mechanically interlocks with a manual operation and an inner lever  59  (described later). 
       FIG. 4  is a perspective view of the latch. mechanism  44 . As illustrated in  FIG. 4 , the latch mechanism  44  includes a base bracket  50 , a ratchet  52 , a ratchet holder  54 , a ratchet lever  56 , an anti-panic lever  58 , and the inner lever  59  in addition to the latch  12  and the outer lever  34  described above. Each element of the latch mechanism  44  is supported or pivotally supported by the base bracket  50 . 
     The latch  12  is pivotally supported by a shaft part  60 , and includes a striker engagement groove  12   a  and a ratchet engagement part  12   b . The latch  12  rotates against a spring (not illustrated) when the striker enters the striker engagement groove  12   a  from a door-opened state, latches the striker at a full-latch position when the ratchet  52  engages with the ratchet engagement part  12   b , and closes the door. 
     The ratchet  52  includes a base lever  64  pivotally supported by a shaft part  62 , and a pole lever  66  including a base shaft part  66   a  pivotally supported by the base lever  64 . The base lever  64  is elastically energized by a spring  65 . The pole lever  66  bends within a predetermined angle range with respect to the base lever  64 . The ratchet  52  is supported by the ratchet holder  54  from a side to hold a substantially linear attitude of the ratchet  52 , and a distal end of the pole lever  66  engages with the ratchet engagement part  12   b  to hold the latch  12  at the full-latch position. 
     The ratchet holder  54  is pivotally supported by a shaft part  68 , and elastically energised by a spring  70  to laterally support the base lever  64 . The ratchet holder  54  rotates against elastic force of the spring  70  based on an operation of the ratchet lever  56 , and is separated from the base lever  64 . The base lever  64  and the pole lever  66  of the ratchet  52  are then caused to be in a buckling state with respect to the base shaft part  66   a , and the pole lever  66  is detached from the ratchet engagement part  12   b  to open the latch  12 . The latch  12  rotates by elastic force to unlatch the striker, and opens the door. By operating the ratchet  52  via the ratchet holder  54 , the operation is enabled to be performed by lighter force as compared with a case of directly operating the ratchet  52 . 
     The ratchet lever  56  is pivotally supported by the base bracket  50 , and includes a passive part  56   a  projecting inward from a rotor shaft, and an action part  56   b  projecting outward from the rotor shaft. In the ratchet lever  56 , the action part  56   b  rotates the ratchet holder  54  when the passive part  56   a  moves upward. 
     The outer lever  34  is pivotally supported by a shaft part  72 , and includes a handle operating part  34   a  projecting outward from the shaft part  72 , and an action part  34   b  and a lever passive piece  34   c  projecting inward from the shaft part  72 . The handle operating part  34   a  is a portion operated by the outer handle. The action part  34   h  is inserted into a hole  58   a  of the anti-panic lever  58 , and acts on the anti-panic lever  58 . The action part  34   b  is also inserted into a deformed hole  80   b  of an open link  80  (described later). The lever passive piece  34   c  is disposed below the action part  34   b , and operated by the inner lever  59 . The outer lever  34  is rotated by an operation of the handle operating part  34   a  or the lever passive piece  34   c , and pushes up the anti-panic lever  58 . 
     The inner lever  59  is pivotally supported by a shaft part  74 , and is swung when the cable  35  is operated, whereby an operation piece  59   a  pushes up the lever passive piece  34   c.    
     The anti-panic lever  58  includes the hole  58   a  into which the action part  34   b  is inserted, and an action piece  58   b  bent at an upper part. The anti-panic lever  58  is pushed up by the action part  34   b  due to rotation of the outer lever  34  when the open link  80  (described later) is at an unlocked position, and the action piece  58   b  pushes up the passive part  56   a  of the ratchet lever  56 . Due to this, the ratchet holder  54  and the ratchet  52  perform an unlatch operation. The anti-panic lever  58  has a structure separated from the open link  80  for an anti-panic mechanism. 
       FIG. 5  is a perspective view of the lock mechanism  46  viewed from obliquely inside rearward, and  FIG. 6  is a perspective view of the lock mechanism  46  viewed from obliquely outside forward. In  FIG. 5 , the case  20  is also briefly illustrated so that arrangement of the lock mechanism  46  can be understood. In  FIG. 5  and  FIG. 6 , the lock mechanism  46  is in the locked state. 
     As illustrated in  FIG. 5  and  FIG. 6 , the lock mechanism  46  includes a cam wheel  76  pivotally supported by a shaft part  76   a , a cam lever  78  that is pivotally supported by a shaft part  78   a  and driven by the cam wheel  76 , the open link (position switching member)  80  driven by the cam lever  78 , a sub-lock lever  82  interlocking with the open link  80 , and an open lever  84  that is pivotally supported by a shaft part  84   a  and driven by the cam wheel  76 . The lock mechanism  46  further includes a lock lever  86  and an auxiliary lever  88  interlocking with the sub-lock lever  82 , and a key lever  90  and a sub-key lever  92  that interlock with a key operation to drive the sub-lock lever  82 . For facilitating identification of components in each drawing, the lock lever  86  is represented by a dark dot. pattern, and the open link  80  is represented by a light dot pattern. 
     The cam wheel  76  has a disk shape, and rotates when teeth disposed on an outer peripheral surface are driven by a worm  94   a  of a rotor shaft of the motor  94 . The teeth are not illustrated. The motor  94  is disposed in the electric component region  42  (refer to  FIG. 3 ). A rotation direction of the cam wheel  76  is represented such that a clockwise direction indicates normal rotation, and a counterclockwise direction indicates reverse rotation based on  FIG. 5 . 
     The cam wheel  76  includes a cam  76   b . The cam  76   b  has a shape having a diameter that gradually increases, from immediately below the shaft part  76   a  in the counterclockwise direction across about 270°, when the cam wheel  76  is at a reference position. The diameter thereof is close to a radius of the cam wheel  76  at a position of about 270°, and the diameter is maintained in the counterclockwise direction to a position of about 180°. 
     As illustrated in  FIG. 6 , an auxiliary component  77  is disposed on an inner surface of the cam wheel  76 . The cam wheel  76  and the auxiliary component  77  are fixed to be substantially one component. A spring  76   c  is disposed inside a sleeve  77   a  formed of the auxiliary component  77 . The spring  76   c  energizes the cam wheel  76  to be at a neutral reference position. The cam wheel  76  can normally rotate and reversely rotate against the spring  76   c  from the reference position due to action of the motor  94 . 
     The auxiliary component  77  includes a projection  77   b  projecting inward from an outer circumference vicinity part, and a first inclined wall  77   c  disposed on substantially the opposite side of the projection  77   b . The projection  77   b  abuts on an elastic stopper  96  disposed in the case  20  (refer to  FIG. 2 ) when the cam wheel  76  reversely rotates, and restricts rotation of the cam wheel  76 . The first inclined wall  77   c  is formed such that the width thereof is increased in the counterclockwise direction from a sleeve surface of the sleeve  77   a  in a radial direction. 
     The cam wheel  76  further includes a second inclined wall  76   d  and a holding wall  76   e . The second inclined wall  76   d  is formed such that the width thereof is increased in the clockwise direction from the sleeve surface of the sleeve  77   a  in the radial direction The first inclined wall  77   c  and the second inclined wall  76   d  are formed to be opposed to each other at close positions, and are inclined in reverse directions. The first inclined wall  77   c  is disposed on an outer side as compared with the second inclined wall  76   d . The holding wall,  76   e  is a wall having a circular arc shape that is disposed on a side slightly closer to the counterclockwise direction than the second inclined wall  76   d , and projects outward along a peripheral surface of the cam wheel  76 . As illustrated in  FIG. 6 , a clockwise direction side of the holding wall  76   e  is closed, and a counterclockwise direction side thereof is opened. 
     Returning to  FIG. 5 , a lower surface  78   d  of the cam lever  78  abuts on the cam  76   b , and when the cam wheel  76  rotates, the cam lever  78  is driven by the cam  76   b  to swing against a spring  78   b  in the counterclockwise direction. A knob  78   c  at a distal end of the cam lever  78  is fitted into a side surface guide groove  80   a  of the open link  80 , and erects the inclined open link  80  when the cam lever  78  swings in the clockwise direction. 
     The deformed hole  80   b  is formed at a lower end of the open link  80 , The action part  34   b  of the outer lever  34  (refer to  FIG. 4 ) is inserted into the deformed hole  80   b , and the open link  80  is lifted up by an operation of the outer lever  34 . The anti-panic lever  58  is assembled to a lower end of the open link  80 , and moves up and down, and is inclined integrally with the open link  80 . 
     The open link  80  is a component to be switched to a locked position of an inclined attitude (an attitude in  FIG. 5 ) and an unlocked position of an erected attitude (refer to  FIG. 8  (b)) by the cam lever  78 . The lock mechanism  46  is caused to be in a locked state when the open link  80  is at the locked position, and the lock mechanism  46  is caused to be in an unlocked state when the open link  80  is at the unlocked position. A position of the open link  80  is switched by the lock lever  86 . 
     That is, when the open link  80  is at the locked position, the anti-panic lever  58  (refer to  FIG. 4 ) does not abut on the ratchet lever  56  (refer to  FIG. 4 ) even in a case of being lifted up by the outer lever  34  because the anti-panic lever  58  is inclined together with the open link  80 , that is, an attempt fails. Thus, the ratchet lever  56  does not operate, and the door is kept being closed as the locked state. 
     On the other hand, when the, open link  80  is at the unlocked position and lifted up by the outer lever  34 , the anti-panic lever  58  is erected together with the, open link  80 , so that the anti-panic lever  58  abuts on and pushes up the ratchet lever  56 . Thus, the ratchet lever  56  operates to cause the unlocked state in which the door may be opened 
     The sub-lock lever  82  is pivotally supported by a shaft part  82   a  to be able to swing, and is swung and driven by the key lever  90  and the sub-key lever  92  to switch between the locked position and the unlocked position of the open link  80 . That is, the sub-lock lever  82  can switch between the locked state and the unlocked state. 
     When the sub-lock lever  82  swings in the counterclockwise direction under action of the key lever  90  and the sub-key lever  92 , an upper portion of the open link  80  is pushed out from the sub-lock lever  82  via an inner knob  86   i  (refer to  FIG. 7( d ) ) of the lock lever  86 , and swings in the clockwise direction to be at the unlocked position. When the sub-lock lever  82  swings in the clockwise direction to return to a previous position, elastic force of the spring  78   b  is transmitted to the open link  80  via the cam lever  78 , and the open link  80  swings in the counterclockwise direction to be at the locked position An arm  98  projecting forward from the shaft part  82   a  is disposed at an upper part of the sub-lock lever  82 . The arm  98  is used as a unit for identifying whether the lock mechanism  46  is in the locked state or the unlocked state, and performs switching operation between a first lock position switch  106  and a second lock position switch  108  (refer to  FIG. 3 ) described later. 
     The open lever  84  is a component used for opening the door based on electric release, that is, a switch operation and the like performed by a driver The open lever  84  includes a cam passive part  84   b  projecting forward and a ratchet operation part  84   c  projecting rearward, and is energized in the clockwise direction by a spring  84   d . When the cam wheel  76  normally rotates, the cam  76   b  pushes down the cam passive part  84   b , the open lever  84  rotates against the spring  84   d  in the counterclockwise direction about the shaft part  84   a , and the ratchet operation. part  84   c  moves upward. When the ratchet operation part  84   c  moves upward, the passive part  56   a  of the ratchet lever  56  is pushed up, and the latch mechanism  44  is unlatched to open the door When the cam wheel  76  returns to the reference position, the open lever  84  is also returned to a reference attitude by the spring  84   d.    
     The open lever  84  can operate the ratchet lever  56  independently of the open link  80 . Thus, with the open lever  84 , the door can be opened based on the electric release unit even when the lock mechanism  46  is in the locked state (that is, the open link  80  is at the locked position). 
     As illustrated. in  FIG. 6 , the lock lever  86  is pivotally supported by a shaft. part  86   a , and includes an arm  86   b  extending upward, an outer knob  86   c  projecting outward from a distal end of the arm  86   b , a first projection  86   e  projecting forward from a downward extending Part  86   d  a second projection  861  projecting forward from the vicinity of the shaft part  86   a , a spring reception part  86   g  projecting outward from the downward extending part  86   d  and two push-out parts  86   h . The outer knob  86   c  is fitted into a guide hole  82   b  formed at a lower end of the sub-lock lever  82 . When the sub-lock lever  82  swings, the lock lever  86  is swung by the outer knob  86   c . The lock lever  86  can be displaced to an acting position for switching the open link  80  from the locked position. to the unlocked position, and a non-acting position at which switching action is not performed on the open link  80  The lock lever  86  is driven by the cam wheel  76  or the sub-lock lever  82 . 
     The spring reception part  86   g  abuts on a bending part  100  of a spring  100  When the sub-lock lever  82  swings, the spring reception part  86   g  gets over the bending part  100  while elastically deforming the bending part  100   a  to be disposed at any one of the locked position and the unlocked position. Accordingly, the sub-lock lever  82  may take any one of the locked. attitude illustrated in  FIG 6  and the unlocked attitude (refer to  FIG. 8( b ) ). 
     The first projection  86   e  is pushed out by the first inclined wall  77   c  Due to this, the lock lever  86  rotates in the clockwise direction. The second projection  86   f  is pushed out by the second inclined wall  76   d . Due to this, the lock lever  86  rotates in the counterclockwise direction. The second projection  86   f  can enter a gap between a side surface of the cam wheel  76  and the first inclined wall  77   c . The two push-out parts  86   h  supports the auxiliary lever  88  from below. 
     As illustrated. in  FIG. 5 , the auxiliary lever  88  is pivotally supported. by the shaft part  86   a  similarly to the lock lever  86 , and includes an arm  86   a  projecting forward and a circular arc projection  88   b  disposed on an upper part of a distal end of the arm  88   a  The circular arc projection  88   b  has a shape that can engage with the holding wail  76   e  (refer to  FIG. 6 ). The auxiliary lever  88  is energized against the lock lever  86  in the counterclockwise direction by a spring  88   c , and a lower surface thereof abuts on the push-out part  86   h  to be supported. 
     Next, the following describes action of the lock mechanism  46 . 
       FIG. 7  is a diagram for explaining an operation of the lock mechanism  46  at the time when the cam wheel  76  normally rotates, (a) is a diagram illustrating a basic state in which the cam wheel  76  is at a reference position, (b) is a diagram illustrating a state in which the cam wheel  76  normally and slightly rotates from the reference position, (c) is a diagram illustrating a state in which the cam wheel  76  normally rotates from the reference position by about 40°, (d) is a diagram illustrating a state in which the cam wheel  76  normally rotates from the reference position by about 90°, (e) is a diagram illustrating a state in which the cam wheel  76  normally rotates from the reference position by about 190°, and (f) is a diagram illustrating a state in which the cam wheel  76  normally rotates from the reference position by about 250°.  FIG. 7  is a diagram of the lock mechanism  46  viewed from the inside, and normal rotation of the cam wheel  76  is the clockwise direction. 
     The cam wheel  76  normally rotates from the basic state illustrated in  FIG 7( a )  due to action of the motor  94 . As illustrated in  FIG. 7( b ) , when the cam wheel  76  slightly rotates, the cam  76   b  abuts on the lower surface  78   d  of the cam lever  78  and starts to drive the cam lever  78  in the counterclockwise direction As illustrated in  FIG. 7( c ) , when the cam wheel  76  rotates by about 40°, a radius expansion starting part  76   ba  of the cam  76   b  abuts on the cam passive part  84   b  of the open lever  84 , and starts to drive the open lever  84  in the counterclockwise direction. As illustrated in  FIG. 7( d ) , when the cam wheel  76  rotates by about 90°, a maximum diameter circular arc part  76   bb  of the cam  761  reaches the lower surface  78   d  of the cam lever  78 , the cam lever  78  is maximally displaced in the counterclockwise direction, and the maximum displacement is maintained thereafter until the state illustrated in  FIG. 7( f )  is caused. When the cam lever  78  is maximally displaced, the open link  80  is pushed out by the knob  78   c , and swings to be at the unlatched position. However, at this point, the sub- 1 ock lever  82 , the lock lever  86 , and the auxiliary lever  88  do not operate and maintain attitudes in  FIG. 7( a ) . 
     When the open lever  84  rotates in the counterclockwise direction, the ratchet operation part  84   c  abuts on and pushes up the passive part  56   a  of the ratchet lever  56 . When the passive part  56   a  is pushed up, the ratchet lever  56  starts to rotate about an axis. 
     As illustrated in  FIG. 7( e ) , when the cam wheel  76  rotates by about 190°, the open lever  84  is driven the counterclockwise direction, and the ratchet operation part  84   c  pushes up the passive part  56   a  of the ratchet lever  56 . Substantially at this point, the open lever  84  starts to act on the ratchet holder  54  (refer to  FIG 4 ), and an unlatch operation is started 
     As illustrated in  FIG. 7( f ) , when the cam wheel  76  rotates by about 250°, the maximum diameter circular arc part  76   bb  of the cam  76   b  reaches the cam passive part  84   b , the open lever  84  is maximally displaced in the counterclockwise direction, the passive part  56   a  of the ratchet lever  56  is sufficiently pushed up, the latch mechanism  44  unlatches the striker, and the door is opened. Thereafter, by stopping electric supply to the motor  94 , the am wheel  76  rotates in the counterclockwise direction due to action of the spring  76   c  (refer to  FIG. 6 ) , and the lock mechanism  46  returns to the basic state illustrated in  FIG. 7( a ) . 
     At the time of such electric release, as illustrated. in  FIGS. 7( a ) to 7( f )  , the open lever  84  rotates under the action of the motor  94  to work on. the latch mechanism  44 , and the striker can be unlatched accordingly. At this point, the open link  80  reciprocates between the locked position and the unlocked position. The open link  80  does not act on the other components, but operates at appropriate time intervals in synchronization with the time of auto-release, so that it is possible to prevent grease from being hardened due to long-term deterioration, or prevent a spring, a lever, and the like made of steel material from rusting. Due to this, the lock mechanism  46  is enabled to smoothly operate in a predetermined situation. 
     Only the open link  80  operates in synchronization with auto-release, and the lock lever  86  does not. operate. 
     Thus, the spring reception part  86   q  of the lock lever  86  does not get over a bending part  100   g , and sound is not generated, so that a sense of incongruity is not given to a user. 
       FIG. 8  is a diagram for explaining the operation of the lock mechanism  46  at the time when the cam wheel  76  reversely rotates and normally rotates, (a) is a diagram illustrating a basic state in which the cam wheel  76  is at The reference position, (b) is a diagram illustrating a state in which the cam wheel  76  reversely rotates from The reference position by about 40°, (c) is a diagram illustrating a state in which the cam wheel  76  normally rotates from the state of (b) by about 40°, and (d) is a diagram illustrating a state in which the cam wheel  76  normally rotates from the state of (c) by about 40°.  FIG. 8  is a diagram of the lock mechanism  46  viewed. from the outside, and reverse rotation of the cam wheel  76  is the clockwise direction. 
     The cam wheel  76  reversely rotates from the basic state illustrated in  FIG. 8( a )  due to action of the motor  94 . As illustrated in  FIG. 8( b )  , when the cam wheel  76  reversely rotates by about 40°, the second inclined wall  76   d  of the cam wheel.  76  presses the second projection  86   f . Due to this, the lock lever  86  rotates in the counterclockwise direction, and the spring reception. part  86   g  gets over the bending part  100   a  of the spring  100  to be displaced to a predetermined inclined position. Following the rotation. of the lock lever  86 , the sub-lock lever  82  is driven by the outer knob  86   c  to rotate in the clockwise direction, the open link  80  is driven by the inner knob  86   i  to rotate in the counterclockwise direction, and the auxiliary lever  88  is driven by the push-out part  86   h  (refer to  FIG 5 ) to rotate in the counterclockwise direction. Due to this, the sub-lock lever  82  and the open link  80  are caused to be at unlocked positions, and the circular arc projection  88   b  of the auxiliary lever  88  is displaced to a position close to the sleeve  77   a.    
     As illustrated in  FIG. 8( c ) , when the cam wheel  76  normally rotates by about 40° from the state of  FIG. 8( b ) ), the cam wheel  76  returns to the position illustrated in  FIG. 8( a ) . However, the spring reception part  86   g  is held by the bending part  100   a , so that the lock lever  86 , the sub-lock lever  82 , and the open link  80  maintain the attitudes illustrated in  FIG. 8( b ) . Due to this, the lock mechanism  46  is caused to be in the unlocked state. 
     At this point, the circular arc projection  88   b  starts to engage with an inner diameter side surface of the holding wall  76   e  of the cam wheel  76 , and the auxiliary lever  88  maintains the attitude illustrated in  FIG 8( b ) . 
     As illustrated. in  FIG. 8( d )  , when the cam wheel. 
       76  further normally rotates by about 40°from the state of  FIG 8( c ) , the first inclined wail  77   c  presses the first projection  86   e . Due to this, the lock lever  86  rotates in the clockwise direction, and the spring reception part  86   g  gets over the bending part  100   a  of the spring  100  to return to the position illustrated in  FIG. 8( a ) . Following the rotation of the lock lever  86 , the sub-lock lever  82  is driven by the outer knob  86   c  to rotate in the counterclockwise direction, the open link  80  is driven by the cam lever  78  (refer to  FIG. 7 ) to rotate in the clockwise direction, and both of the sub-lock lever  82  and the open link  80  return to the state illustrated in  FIG. 8( a ) . 
     On the other hand, the circular arc projection  88   b  engages with the inner diameter side surface of the holding well  76   e  of the cam wheel  76 , so that the auxiliary lever  88  maintains the attitude illustrated in (d). When the cam wheel  76  further normally rotates, an end part on a counterclockwise side of the circular arc projection  88   b  abuts on a closed surface on the counterclockwise side of the holding wall  76   e  to restrict rotation. Due to this, the cam wheel  76  can be prevented from excessively rotating. Thereafter, when the cam wheel  76  reversely rotates to the position illustrated in  FIG. 8( a ) , engagement between the circular arc projection  88   b  and the holding wall  76   e  is released, so that the auxiliary lever  88  rotates in the clockwise direction by elastic force of the spring  88   c  to return to the position illustrated in  FIG. 8( a ) . In this way, the lock mechanism  46  returns to a basic attitude illustrated in  FIG. 8( a )  as a whole. As described above, in the door latch device  10 , engagement of the latch mechanism  44  can be released, and the locked state and the unlocked state of the lock mechanism  46  can be switched by the single motor  94 . 
     Returning to  FIG. 3 , the electric components of the door latch device  10  include a latch position. switch  102  that detects a rotation state of the latch  12 , a key lever position switch  104  that detects a rotation state of the sub-key lever  92 , and a first lock position switch  106  and a second lock position switch  108  that detect a rotation state of the sub-lock lever  82  via the arm  98  in addition to the motor  94  described above. 
     The motor  94 , the key lever position switch  104 , the first lock position switch  106 , and the second lock position switch  108  are collectively disposed in the electric component region  42 , but the latch position switch  102  is connected to two terminals  110   a  and  110   b  extending from the electric component region  42  so as to be disposed in the vicinity of the latch  12  The terminals  110   a  and  110   b  are held by a plate  112   
       FIG. 9  is an exploded perspective view of the electric components, components that house the electric components, and the like viewed from obliquely forward outside, and  FIG. 10  is an exploded perspective view of the electric components, the components that house the electric components, and the like viewed from obliquely forward inside 
     As illustrated in  FIG. 9  and  FIG. 10 , the door latch device  10  includes a circuit board  120  that controls the motor  94 . The number of motors controlled by the circuit board  120  may be plural. At an upper part of an outer surface of the case  20 , a recessed part  122  is formed in a region corresponding to a back side of the electric component region  42 . An outer surface of the recessed part  122  is covered by the second cover  24  described above to form a second housing space  124 . The circuit board.  120  is housed in the second housing space  124 . As described above, the first housing space  36  is partitioned into the mechanism region  40  in which the machine mechanism  38  is disposed, and the electric component region  42  as a remaining region thereof. Thus, the second housing space  124  is disposed on the back side of the electric component region  42  across the case  20 . Due to this, the electric components and the like are disposed in a concentrated manner, and a conductive material can be shortened. The electric component region  42  occupies the forward. upper part as described above, so that the circuit board  120  disposed on the recessed part  122  of the second housing space  124  is also disposed on the forward upper part based on orientation of the vehicle The striker entry groove  14  into which waterdrops may penetrate is disposed rearward, so that waterdrops are prevented from reaching the second housing space  124  and the circuit board  120  therein. An external waterproof seal  126  is disposed between an edge of the recessed part  122  and the second cover  24  in the case  20 , and the second housing space  124  is waterproofed against the outside. The external waterproof seal  126  is obtained by cutting a string-like sealing material by a predetermined length, and a dedicated molding is not required. The external waterproof seal  126  is disposed such that lower ends thereof are slightly overlapped with each other. 
     The circuit board  120  includes pins  128 ,  130 ,  132 ,  134 , and  136  (hereinafter, also representatively referred to as pins P) erected toward the outside, pin holders  138 ,  140 ,  142 ,  144 , and  146  (hereinafter, also representatively referred to as pin holders H) supporting the pins with respect to the circuit board  120  by covering the periphery of bases of the pins P and two positioning holes  147   a  and  147   b . The pin holder H has appropriate strength, and can presses an internal waterproof seal B (described later). The pin holder H has appropriate elasticity, and exhibits sealing action for the pin P to be inserted The pin holder H is made of resin, for example, a molding made of polyacetal. 
     The two pins  128  are connected t.o the motor  94 . The three pins  130  are connected. to the first lock position switch  106  and the second lock position switch  108 . The three pins  132  are connected. to the key lever position switch  104 . The two pins  134  are connected. to the latch position switch  102  via the terminals  110   a  and  110   b  The several pins  136  project inward from a hole of a terminal wall  30   a  of the first cover  22  to be part of the coupler  30 . In other words, the coupler  30  includes the terminal. wall  30   a  disposed on the first cover  22 , and the pins  136  that are erected from the circuit board  120 , pass through a pin hole  156  (described later), and project from the hole of the terminal wall  30   a . The pin P is soldered on a back surface of the circuit board  120 . 
     The pin holder  138  holds the two pins  128 , the pin holder  140  holds the three pins  130  in series, the pin holder  142  holds the Three pins  132  in series, the pin holder  144  holds the two pins  134 , and the pin holder  146  holds the several pins  136  in two columns. 
     The positioning hole  147   a  and the positioning hole  147   b  are disposed at positions distant from each other. The positioning hole  147   a  is a round hole, the positioning hole  147   b  is a long hole directed to the positioning hole  147   a , and a manufacturing error of positioning pins  167   a  and  167   b  (described later) is allowed The circuit board  120  further includes a CPU, a memory, resistance, a capacitor, and the like (not illustrated). The circuit board  120  has an irregular shape substantially along the second housing space  124 . 
     Pin holes  148 ,  150 ,  152 ,  154 , and  156  (hereinafter, also representatively referred to as pin holes A) are formed on a bottom plate  122   b  of the recessed part  122  in the case  20 . The pin hole A establishes communication. between the first housing space  36  and the second housing space  124 . The pins  128 ,  130 ,  132 ,  134 , and  136  respectively project from the pin holes  148 ,  150 ,  152 ,  154 , and  156  in order toward. the first housing space  36 , and are inserted into pin connection holes disposed on the respective electric components to be electrically connected. Each of the electric components is held by a holding wall  165  disposed on the outer surface of the case  20  Between outer peripheries of the pin holders  138 ,  140 ,  142 ,  144 , and  146  and the pin holes  148 ,  150 ,  152 ,  154 , and  156 , rectangular internal waterproof seals  158 ,  160 ,  162 ,  164 , and  166  having a ring shape (hereinafter, also representatively referred to as internal waterproof seals B) are disposed in order. The internal waterproof seal B waterproofs a space between the first housing space  36  and the second housing space  124 . The second housing space  124  is waterproofed by the external waterproof seal  126  and the internal waterproof seal B, and suitable for housing the circuit board  120  The internal waterproof seal preferably has a rectangular ring shape corresponding to the corresponding pin hole A, but parts of a non-ring-shaped body may be overlapped to be used like the external waterproof seal  126  depending on a condition. The circuit board  120  is disposed on an upper part than the striker entry groove  14  (refer to  FIG. 3 ). Specifically, a lower part of the circuit board  120  has a horizontal linear shape, and this portion is disposed on an upper part than an upper end of the striker entry groove  14 . Even if the external waterproof seal  126  and the internal waterproof seal.  13  are not disposed, waterdrops entered through the striker entry groove  14  are prevented from reaching the circuit board  120   
     Two positioning pins  167   a  and  167   b , and a plurality of inner circuit board supporters (first circuit board supporters)  169  are further formed on the bottom plate  122   b . The positioning pins  167   a  and  167   b  are inserted into the positioning holes  147   a  and  147   b , and the circuit board  120  is positioned. The inner circuit board supporter  169  is disposed at a position along the periphery of the circuit board  120 , and abuts on an inner surface of the circuit board  120 . 
     A seal groove  173  is formed along an outer circumference of a surrounding wall  122   a  surrounding the recessed part  122  The external waterproof seal  126  is disposed on the seal groove  173  An overlap groove  173   a  for causing lower ends of the external waterproof seal  126  to be overlapped and disposed is formed in the seal groove  173 . Projection pairs  173   b  projecting from both sides in an opposed manner are formed. at a plurality of points including a bending point in the seal groove  173 . The projection pair  173   b  is a stopper for the external waterproof seal  126 . A space between the recessed part  122  and the second cover  24  are entirely waterproofed by he external waterproof seal  126 . 
     Pairs of support projections  168 ,  170 ,  172 ,  174 , and  176  (hereinafter, also representatively referred to as support projections C) are formed on an inner surface of the second cover  24 . The support projections  168 ,  170 ,  172 ,  174 , and  176  are disposed at positions opposed to the pin holders  138 ,  140 ,  142 ,  144 , and  146  in order across the circuit board  120 . The support projection C supports a back side of an. abutting part of the pin holder H in the circuit board  120  The support projection C and a leg part Hd (described later) are disposed on both sides across the pin P in a longitudinal direction of the pin holder H. 
     On the inner surface of the second cover  24 , two positioning posts I 77   a  and  177   b , a plurality of outer circuit board. supporters (second circuit board supporters)  178 , a seal pressing projection  180 , and an osmosis membrane holder  182  are further formed A round hole is formed on the positioning post  177   a , and a long hole directed to the positioning post  177   a  is formed on the positioning post  177   b . The positioning pins  167   a  and  167   b  passed through the positioning holes  147   a  and  147   b  are inserted into respective holes of the positioning posts  177   a  and  177   b , and the second cover  24  is positioned. 
     The outer circuit board supporter  178  is disposed at a position along the periphery of the circuit board  120  and a position opposed to the inner circuit board supporter  169  via the circuit board  120 , and sandwiches and holds the circuit board  120  between itself and the inner circuit board supporter  169 . The inner circuit board. supporter  169  and the outer circuit board supporter  178  are disposed to be opposed to each other, and to have the same cross-sectional shape and the same orientation. 
     The seal pressing projection  180  is a narrow projection having a substantially ring shape along the seal groove  173 , and presses an outer surface of the external waterproof seal  126 . The external waterproof seal  126  exhibits sealing action by being pressed to be sealed by the seal pressing projection  180   
     The osmosis membrane holder  182  is a cylindrical body projecting outward, and has a hole  182   a  at a distal end thereof. An osmosis membrane filter  184  is attached to the osmosis membrane holder  182  from inside. The osmosis membrane filter  184  can prevent passage of waterdrops and cause water vapor to pass through the hole  182   a , and prevents the second housing space  124  from being caused to be in a high humidity state. The osmosis membrane holder  182  and the osmosis membrane filter  184  are disposed in a space under the circuit. board  120  in the second housing space  124  The osmosis membrane holder  182  is disposed in a range surrounded by an abutting part of the external waterproof seal  126  on the second cover  24 . 
     A plurality of screw holes  186  are disposed on the periphery of the second cover  24 , and when a screw  188  passed through the screw hole  186  is screwed to a screw post  190  disposed on the case  20 , the second cover  24  is fixed to the case  20 . 
     A plurality of hooks  192  are disposed on the periphery of the first cover  22 , and when the hook  192  engages with a pawl  194  disposed on the case  20 , the first cover  22  is fixed to the case  20 . After the first cover  22  and the second cover  24  are attached to the case  20 , the waterproof cover  26  is attached thereto from above. With the waterproof cover  26 , even if the external waterproof seal  126  and the internal waterproof seal B are not disposed, waterdrops from above can be fairly prevented from reaching the circuit board  120  within the second housing space  124  covered by the second cover  24 . 
     The first housing space  36  formed between the case  20  and the first cover  22  is not completely waterproofed, and has what is called a dripproof structure. This is because that the dripproof structure is sufficient for each component housed in the first housing space  36 . On the other hand, as described above, the second housing space  124  has a waterproof structure due to the external waterproof seal  126  and the internal waterproof seal B because precision electronic component and the like are mounted on the circuit board  120 . 
     Next, the following further describes a structure for detecting a position of the sub-lock lever (operation detection target)  82  by the first lock position switch (first position switch)  106  and the second lock position switch (second position switch)  108 . The three pins  130  described. above are distinguished from each other as a first signal pin  130   a , a second signal pin  130   b , and a common pin  130   c  (refer to  FIG. 13 ) hereinafter. As described above, each of the first signal pin  130   a , the second signal pin  130   b , and the common pin  130   c  is erected from the circuit board  120 . The first switch  106  and the second switch.  108  are stacked, so that the first signal pin  130   a , the second signal pin  130   b , and the common pin  130   c  are close to each other, and can be collectively disposed on the circuit board  120 , which is preferable on a print pattern layout. These pins may have a form such that, for example, an end part of a member such as the terminals  110   a  and  110   b  (refer to  FIG. 3 ) is erected from the plate  112  or the housing. 
     Hereinafter, the first lock position switch  106  and the second lock position switch  108  are simply referred to as the first switch  106  and the second switch  108 . As described later, the first switch  106  and the second switch  108  are stacked and disposed at positions shifted from each other in the X-direction (refer to  FIG. 15 ). 
       FIG. 11  is a circuit diagram of the door latch device  10  to which the first switch  106  and the second switch  108  are applied. The first switch  106  and the second switch  108  have the same structure, and each include a first contact hole  200   a  connected to a normally open contact, a second contact hole  200   b  connected to a normally closed contact (that is, a reverse format of the first contact hole  200   a ), and a common contact hole  200   c  connected to a common contact. 
     The first signal pin  130   a  is inserted into the first contact. hole  200   a  of the fir switch  106  to be electrically conducted (refer to  FIG. 14 ). The second signal pin  130   b  is inserted into the common contact hole  200   c  of the second switch  108  to be electrically conducted (refer to  FIG. 14 ). The common pin  130   c  is inserted into the common contact hole  200   c  of the first switch  106  and the first contact hole  200   a  of the second switch  108  to be electrically conducted (refer to  FIG. 14 ). Three pins, that is, the first signal pin  130   a , the second signal pin  130   b , and the common pin  130   c  are enough for the pins P related to the first switch  106  and the second switch  108 . In this case, the second contact. hole  200   b  is not used in any of the first switch  106  and the second switch  108 . 
     Each of the first signal pin  130   a , the second signal pin  130   b , and the common pin  130   c  is soldered to the circuit board  120 . Signals related to the first signal pin  130   a  and the second signal pin  130   b  are independently read by a reading part  202  on the circuit board  120 . The signals read by the reading part  202  are supplied to a CPU (not illustrated), and used for control determination. 
     As described later, the first switch  106  and the second switch  108  perform a switch operation at the same timing due to an operation of the sub-lock lever  82  as the operation detection target. Thus, the reading part  202  can acquire an operation detection signal of the sub-lock lever  82  twice, and even in a case in which any one of the first switch  106  and the second switch  108  breaks down, control processing can be continued based on a detection signal obtained by the other of the first switch  106  and the second switch  108  in a normal state. 
     In this case, the CPU that performs control monitors the detection signal of the first switch  106  and the detection signal of the second switch  108 , and if any one of the detection signals is changed, control processing based on the detection signal may be performed. In a case in which the detection signal of the first switch  106  is not synchronized with the detection signal of the second switch  108 , it may be determined that one of the first switch  106  and the second switch  108  the detection signal of which is not changed breaks down, and some kind of warning processing may be performed. 
       FIG. 12  is a perspective view of the first switch  106 . As described above, the second switch  108  also has the same structure. As illustrated in  FIG. 12 , the first switch  106  has a slightly flat boy shape along the XY-plane formed by the X-direction and the Y-direction or to each other, and a dimension in the Z-direction orthogonal to the X- and Y-directions is slightly small. In this case, the Z-direction is an inward/outward direction. The first switch  106  includes the first contact hole  200   a , the second contact hole  200   b , and the common contact hole  200   c  described above, and further includes an actuator  204  and 
     Positioning holes  206   a  and  206   b . The first contact hole  200   a , the second contact hole  200   b , and the common contact hole  200   c  are disposed side by side in the X-direction, pass through the first switch  106  in the Z-direction, and open on a bottom part of a recessed part  208 . A surface opposite to a surface on which the actuator  204  is disposed has a stepped shape in which an upper stage part  210   a  and a lower stage part  210   b  project. The positioning holes  206   a  and  206   b  pass through the upper stage part  210   a  and the lower stage part  210   b  in the Z-direction. The positioning holes  206   a  and  206   b  are disposed in the vicinity of both ends in the X-direction. 
     The actuator  204  is disposed on a surface of a main body part, and moves forward and backward in the Y-direction. At the time when the first switch  106  does not act, the actuator  204  is in a projecting state, the first contact hole  200   a  and the common contact hole  200   c  are opened, and the second contact hole  200   b  and the common contact hole  200   c  are closed. When the actuator  204  is pushed against elastic force by external force, the first switch  106  is caused to be in an acting state, the first contact hole  200   a  and the common contact hole  200   c  are closed, and the second contact hole  200   b  and the common contact hole  200   c  are opened. 
       FIG. 13  is an exploded perspective view of the first switch  106 , the second switch  108 , and the case  20 . The case  20  in a range illustrated in  FIG. 13  corresponds to the bottom plate  122   b  described above, that is, a portion at which the pin hole  150  is disposed and the periphery thereof. As illustrated in  FIG. 13 , holding walls  165   a ,  165   h ,  165   c ,  165   d , and  165   e , mounts  212   a ,  212   b ,  212   c , and  212   d , and positioning pins  214   a ,  214   h , and  214   c  are disposed in the case  20 . 
     The mounts  212   a  and  212   b  are low bulging parts on which the second switch  108  is placed. The mount  212   a  is disposed on one side in the Y-direction (Y 1 -direction in  FIG. 13 ) , and the mount  212   b  is disposed on the other side (Y 2 -direction in  FIG. 13 ) across the pin hole  150 . The mount  212   a  is formed in the X-direction while being in contact with the pin hole  150 . The mount  212   b  has a “U”shape. The mount  212   a  and the mount  212   b  support. 
     substantially the entire circumference of a lower surface of the second switch  108 . 
     The mounts  212   c  and  212   d  are slightly high bulging parts on which the first switch  106  is placed. The mount  212   c  is disposed in the Y 1 -direction, and the mount.  212   d  is disposed in the Y 2 -direction across the pin hole  150 . The mount  212   c  is formed to be in contact with the pin hole  150 . The mount  212   d  has a “U”shape. The mount  212   c  and the mount  212   d  support a substantially half of a lower surface of the first switch  106  in the X-direction (X1-direction in  FIG. 13 ). The mount  212   c  and the mount  212   d  are disposed on the X1-direction side as compared with the mount  212   a  and the mount  212   b , and a dimension in the X-direction is substantially half of the mount  212   a  and the mount  212   b , respectively. Dimensional differences in the Z-direction between the mount  212   c  and the mount  212   a , and between the mount  212   d  and the mount  212   b  are equal to a dimension in the Z-direction of the second switch  108 . 
     The holding wall  165   a  is a slightly high bulging part supporting part of  171 -direction surfaces of the first switch  106  and the second switch  108 , and disposed on the Y1-direction side as compared with the mount  212   a  The holding wail  165   b  is a bulging part supporting part of a Y2-direction surface of the second switch  108 , and connected with the mount  212   d . The holding wall  162  is a bulging part supporting an X1-direction surface of the second switch  108 . The holding wall  165   c  also serves as part of the mount  212   d . The holding wall  165   d  is a bulging part supporting part of a Y2-direction surface of the first switch  106 , and erected from an inner side of the mount  212   d . The holding wall  165   d  is integrated with the holding wall  165   b . The holding wall  165   e  is a bulging part. supporting an X1-direction surface of the first switch  106 , and erected from an inner surface of the mount  812   d.    
     The positioning pin  214   a  is inserted into the positioning hole  206   a  of the first switch  106 . The positioning pin  214   a  is erected from an inner surface of the mount  212   c . The positioning pin  214   b  is inserted into the positioning hole  206   a  of the second switch  108 . The positioning pin  214   c  is inserted into the positioning hole  206   b  of the second switch  108 . The positioning pins  214   b  and  214   c  are erected from an inner surface of the mount  212   a.    
       FIG. 14  is a partial cross-sectional side view of the first switch  106  and the second switch  108  in a state of being stacked and assembled, and the periphery thereof.  FIG. 14  illustrates the first switch.  106  and the second switch  108  viewed from the Y1-direction (refer to  FIG. 13 ), and the holding walls  165   a  to  165   e  and the like are not illustrated. 
     As illustrated in  FIG. 14 , the first switch  106  and the second switch  108  are stacked in the Z-direction without a gap. The first switch  106  and the second switch  108  are disposed to be shifted from each other in the X-direction. Specifically, the first switch  106  is shifted in the Xi-direction with respect to the second switch  100 , the common contact hole  200   c  of the first switch  106  is matched with the first contact hole  200   a  of the second switch  108  in the X-direction, and the common pin  130   c  is inserted through the common contact hole  200   c  and the first contact hole  200   a  to make continuity therebetween. A substantially half on a distal end side of the first signal pin  130   a  is inserted into the first contact hole  200   a  of the first switch  106 , and a substantially half on a base side thereof is exposed. A substantially half on a base side of the second signal pin  130   b  is inserted into the common contact hole  200   c  of the second switch  108 , and a substantial y half on a distal end side thereof is exposed. The first switch  106  and the second switch  108  are not shifted from each other in the Y-direction (refer to  FIG. 13 ). 
     Two slightly low projections  216   a  and  216   b , and one slightly high. projection  216   c  are disposed side by side in the X-direction on the first cover  22 . An inner surface of the first switch.  106  is held by the projections  216   a  and  216   b , and an outer surface thereof is held by the mounts  212   c  and  212   d , and the second switch.  108 . An inner surface of the second. switch  108  is held. by the first switch  106  and the projection  216   c , and an outer surface thereof is held by the mounts  212   a  and  212   b.    
     Waterproof treatment. is performed. on the second housing space  124  as a region in which the circuit board  120  is disposed with the internal waterproof seal  160  around the pin hole  150  with respect to the first housing space  36  as a region in which the first switch  106  and the second switch  108  are disposed The circuit board  120  is sandwiched and held to be stable by the pin holder  140  and the support projection  170  In this case, the bottom plate  122   b  serves as a partition plate that partitions between the first housing space  36  and the second housing space  124 . 
       FIG. 15  is a perspective view illustrating the first switch  106 , the second switch  108 , and the periphery thereof inside the door latch device  10   FIG 15  corresponds to an upper portion of  FIG. 3 . 
     As illustrated in  FIG. 15 , each actuator  204  of the first switch  106  and the second switch  108  projects from the main. body part in the Y2-direction. The shaft. part  82   a  of the sub-lock lever  82  is present at a position in the Y2-direction from a substantial center of two actuators  204 . The shaft part  82   a  is a shaft in the Z-direction. 
     As described above, the arm  98  projecting from the shaft part  82   a  is disposed on an upper part of the sub-lock lever  82 . A first cam  98   a  and a second cam  98   b  are disposed at a distal end of the arm  98 . The first cam  98   a  and the second cam  98   b  are shifted from each other in the Z-direction, the first cam  98   a  is disposed on an inner side, and the second cam  98   b  is disposed on an outer side. 
     The first cam  98   a  and the actuator  204  of the first. switch  106  are at the same position with respect to the Z-direction. The second cam  98   b  and the actuator  204  of the second switch.  108  are at the same position with respect to the Z-direction. 
     The first cam  98   a  and the second cam  98   b  are disposed to be shifted from each other in a circumferential direction with respect to the shaft part  82   a . The arm  98  is appropriately long, so that a shift between the first cam  98   a  and the second can:  98   b  in the circumferential direction can be regarded as a shift on a substantially straight line, and is equal to a shift between the two actuators  204  in the X-direction The first switch  106  and the second switch  108  are stacked, and a shift amount between the two actuators  204  in the X-direction is small, so that a shift amount between the first cam  98   a  and the second cam  98   b  is also small. Thus, the arm  98  can be set to be relatively narrow. 
       FIG. 16  is a diagram illustrating an operational relation among the first switch  106 , the second switch  108 , and a sub-lock lever  82 , (a) is a diagram. illustrating the sub-lock lever  82  in a state of a locked attitude, and (b) is a diagram illustrating the sub-lock lever  82  in a state of an unlocked attitude. 
     As illustrated. in  FIG. 16( a ) , when the sub-lock lever  82  is in the locked attitude, the first cam  98   a  is disposed on. a side slightly distant from the actuator  204  of the first switch  106  in the X1-direction, and the second cam  98   b  is disposed on a side slightly distant from the actuator  204  of the second switch  108  in the X1-direction. At this point, each. of the first switch  106  and the second switch  108  is in a non-acting state, and is in the state illustrated in  FIG. 11 . That is, each first contact hole  200   a  is opened with respect to the common contact hole  200   c . The reading part  202  reads that each first contact hole  200   a  is opened with respect to the common contact hole  200   c  from the first signal pin  130   a  and the second signal pin  130   b.    
     As illustrated in  FIG 16( b ) , when the sub-lock lever  82  is in the unlocked attitude, the first cam  98   a  and the second cam  98   b  are displaced from the state illustrated in  FIG. 16( a )  in a substantial X2-direction (reverse direction of X1 following the rotation of the sub-lock lever  82 . The first cam  98   a  pushes the actuator  204  of the first switch  106  in the Y2-direction, and the second cam  98   b  pushes the actuator  204  of the second switch  108  in the Y2-direction. Due to this, the first switch and the second switch perform a switch operation at the same timing due to the operation of the sub-lock lever  82 , and each of the first switch  106  and the second switch  108  is caused to be in the acting state. That is, each first contact hole  200   a  (refer to  FIG. 11 ) is closed with respect to the common contact hole  200   c . The reading part  202  reads that each first contact hole  200   a  is closed with respect to the common contact hole  200   c  from the first signal pin  130   a  and the second signal pin  130   b . Thus, the reading part  202  reads the attitude of the sub-lock lever  82  twice, so that the operation thereof can be detected more securely. Even if any one of the first switch.  106  and the second switch  108  breaks down and does not perform the switch operation, predetermined control can be performed based on the switch operation of the other one thereof in a normal state. Additionally, the first switch  106  and the second switch  108  are stacked, so that an occupied area is small 
       FIG. 17  is a circuit diagram according to a modification to which a second switch  106 A and a first switch  108 A are applied in place of the first switch  106  and the second switch  108  described above As is clear from comparison between  FIG 11  and  FIG. 17 , the former is a normally open circuit, and the latter is a normally closed circuit. 
     In the first switch  106  and the second switch  108  described above (refer to  FIG. 11 ), the first contact hole  200   a  is a normally open contact and the second contact hole  200   b  is a normally closed contact. In contrast, in the first switch  108 A and the second switch  106 A, the first contact hole  200   a  is the normally closed contact and the second contact hole  200   b  is the normally open contact Although not illustrated herein, the other configurations of the first switch  108 A and the second switch  106 A are the same as those of the first switch  106  and the second switch  108 . A first signal pin  130 Aa in  FIG. 17  is the same as the second signal pin  130   b  in  FIG. 11 , a second signal pin  130 Ab is the same as the first signal pin  130   a  in  FIG. 11 , and only designations thereof are different. 
     In this case, the first signal pin  130 Aa is inserted into the first contact hole  200   a  of the first switch  108 A to be electrically conducted. The second signal pin  130 Ab is inserted into the common contact hole  200   c  of the second switch  106 A to be electrically conducted The common pin  130   c  is inserted into the common contact hole  200   c  of the first switch  108 A and the first contact hole  200   a  of the second switch  106 A to be electrically conducted In this case, the second contact hole  200   b  is not used in any of the first switch  108 A and the second switch  106 A. 
     In a case of using such a circuit, when the sub-lock lever  82  is in the locked attitude (refer to  FIG 16( a ) ), each of the first switch  1081  and the second switch  106 A is in the non-acting state, and each first contact hole  200   a  is closed with respect to the common contact hole  200   c . The reading part  202  reads that each first contact hole  200   a  is closed with respect to the common contact hole  200   c  from the first signal pin  130 Aa and the second signal pin  130 Ab. 
     When the sub-lock lever  82  is in the unlocked attitude (refer to  FIG. 16( b ) ), each. of the first switch  108 A and the second switch  106 A is in the acting state That is, each first contact hole  200   a  is opened with respect to the common contact hole  200   c . The reading part  202  reads that each first contact hole  200   a  is open with respect to the comm cm contact hole  200   c  from the first signal pin  130 Aa and the second signal pin  130 Ab. Thus, similarly to the case of the circuit illustrated in  FIG. 11 , the reading part  202  can detect the attitude of the sub-lock lever  82  twice. 
     The present invention is not limited to the embodiment described above, and can be freely modified without departing from the gist of the present invention, obviously. 
     REFERENCE SIGNS LIST 
       10  Door latch device 
       12  Latch 
       14  Striker entry groove 
       16  Cover plate 
       18  Body 
       20  Case 
       22  First cover 
       24  Second cover 
       30  Coulter 
       32  Key cylinder coupling part 
       34  Outer lever 
       36  First housing space 
       38  Machine mechanism 
       40  Mechanism region 
       42  Electric component region 
       44  Latch mechanism 
       46  Lock mechanism 
       52  Ratchet 
       54  Ratchet holder 
       58  Anti-panic lever 
       59  Inner lever 
       82  Sub-lock lever (operation detection target) 
       84  Open lever 
       94  Motor 
       98  Arm 
       98   a  First cam 
       98   b  Second cam 
       106 ,  108 A First position switch, first switch 
       108 ,  106 A Second position switch, second switch 
       120  Circuit board 
       122  Recessed part 
       124  Second housing space 
       126  External waterproof seal 
       128 ,  130 ,  132 ,  134 ,  136 , P Pin 
       130   a  First signal pin 
       130   b  Second signal pin 
       130   c  Common pin 
       130 Aa First signal pin 
       130 Ab Second signal pin 
       138 ,  140 ,  142 ,  144 ,  146 , H Pin holder 
       148 ,  150 ,  152 ,  154 ,  156 , A Pin hole 
       158 ,  160 ,  162 ,  164 ,  166 ,  13  Internal waterproof seal 
       168 ,  170 ,  172 ,  174 ,  176 , C Support projection 
       169  Inner circuit board supporter 
       200   a  First contact hole 
       200   b  Second contact hole 
       200   c  Common contact hole 
       202  Reading part