Abstract:
A lock device includes: a case member that is attached to a lock target; a sleeve member that is housed inside the case member such that the sleeve member is movable along an axial direction; a plunger member that is housed inside the sleeve member such that the plunger member is movable along the axial direction; a coupling structure in which a key insertion hole that allows insertion of a key is formed, the coupling structure being placed inside the plunger member and coupling together the sleeve member and the plunger member; and a manipulable member that is rotatably coupled to the sleeve member and the plunger member, rotates when just the plunger member moves, and releases the locked state of the lock target. The coupling structure is configured to release the coupling just when a regular key is inserted into the key insertion hole.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 USC 119 from Japanese Patent Application No. 2007-92813, the disclosure of which is incorporated by reference herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a lock device that locks and unlocks a lock mechanism or the like by manipulation of a key inserted into a key insertion hole. 
         [0004]    2. Description of the Related Art 
         [0005]    A lock device disposed in a door of an automobile or the like is, for example, disposed with a cylindrical case member, a sleeve member that is rotatably disposed inside the case member, a plunger member that is rotatably disposed inside the sleeve member, a rear rotor that is rotatably disposed so as to face the plunger member in an axial direction, and a lock lever that is disposed so as to rotate integrally with the rear rotor (e.g., see Japanese Patent Application Publication (JP-A) No. 8-4387). 
         [0006]    This lock device is configured such that, when a regular key is inserted into a key hole, the plunger member releases the state of engagement between the plunger member and the sleeve member, just the plunger member becomes rotatable, and the plunger member can cause the rear rotor to rotate. Thus, the lock lever rotates together with the rear rotor, and a lock mechanism in a door of a vehicle or the like is unlocked by the manipulating force of the lock lever. 
         [0007]    Further, when a key substitute, such as a key whose shape is different from that of the regular key or a driver (these will generically be called an “irregular key” below), is inserted into the key hole in the plunger member and forcibly rotated, tumbler members maintain the state of engagement between the plunger member and the sleeve member, and the plunger member and the sleeve member integrally rotate, so the plunger member cannot cause the rear rotor to rotate. 
         [0008]    In other words, the lock device is configured such that the plunger member and the sleeve member integrally rotate even when an irregular key that has been inserted into the plunger member is rotated, but the rear rotor and the lock lever cannot be caused to rotate, and the lock mechanism is not unlocked. 
         [0009]    That is, in the lock device described in JP-A No. 8-4387, when the regular key is inserted into the key hole and the plunger member is caused to rotate, the lock mechanism can be unlocked, but when the irregular key is inserted into the key hole and the irregular key is forcibly rotated, the plunger member and the sleeve member rotate together, so the lock mechanism is not unlocked. Moreover, because the plunger member and the sleeve member rotate together, unreasonable force does not act on the tumbler members that engage the plunger member and the sleeve member, so the lock device is structured such that damage to the tumbler members and the like is prevented. 
         [0010]    However, when the lock device is to be unlocked, a plate-shaped key must be inserted into the key hole in the lock device and rotated counter to the rotational resistance of the plunger member, the rear rotor and the lock lever and the actuated resistance of the lock mechanism. 
         [0011]    For this reason, in regard to the key used in this lock device, the material thereof is limited to a high-strength material such as iron or stainless steel, and it is necessary to make the thickness of the key sufficiently thick in accordance with the size of the transfer torque. 
         [0012]    Further, in this lock device, plural plate-shaped tumbler members arranged in the plunger member are disposed at predetermined intervals in the axial direction and so as to be movable in an axis-orthogonal direction. When a key is inserted into the key hole, the concavo-tongue portions of the key and the key insertion hole in the plunger member contact each other. In the case of the regular key, all of the tumbler members move to regular positions and just the plunger member rotates, but in the case of the irregular key, at least one of the tumbler members moves to an irregular position, the plunger member and the sleeve member integrally rotate, and the rear rotor cannot be caused to rotate. 
         [0013]    On the other hand, it is necessary to increase the number of the tumbler members in order to diversify the types of keys, and there is also the problem that the axial direction length of the plunger member must be made longer when the number of the tumbler members disposed at predetermined intervals in the plunger member is increased. 
       SUMMARY OF THE INVENTION 
       [0014]    In consideration of the above-described circumstances, the present invention provides a lock device that can make the mechanical strength required of the key small and control the length of the plunger member from becoming longer even when the number of the tumbler members is increased. 
         [0015]    A first aspect of the invention is a lock device including: a case member that is attached to a lock target; a sleeve member that is housed inside the case member such that the sleeve member is movable along an axial direction; a plunger member that is housed inside the sleeve member such that the plunger member is movable along the axial direction; tumbler members that are arranged at predetermined intervals in the axial direction inside the plunger member and disposed such that the tumbler members are movable in a direction orthogonal to the axial direction; recessed portions that are disposed in an inner wall of the sleeve member; tongue portions that are formed on the tumbler members, engage with the recessed portions, and cause the sleeve member and the plunger member to move integrally in the axial direction; energizing members that energize the tumbler members in a direction where the tongue portions engage with the recessed portions; key insertion holes that are formed in the tumbler members, engage with concavo-tongue portions formed on a regular key inserted into the plunger member, cause the tumbler members to move in a direction where the state of engagement between the tongue portions and the recessed portions is released, and also allow insertion of an irregular key; a contact wall that is disposed in the plunger member, is pushed against by a distal end portion of either the regular key or the irregular key inserted into the plunger member, and causes the plunger member to move in the axial direction; and a manipulable member that is rotatably coupled to the sleeve member and the plunger member, rotates when just the plunger member moves, and releases the locked state of the lock target, wherein engagement positions where the tongue portions disposed on the tumbler members that are adjacent and the recessed portions engage with each other are arranged such that the engagement positions are offset in a thickness direction of the keys. 
         [0016]    According to this configuration, when the irregular key is inserted into the plunger, the state of engagement between the tongue portions formed on the tumbler members and the recessed portions formed in the sleeve member is maintained, and the sleeve member and the plunger member move integrally in the axial direction inside the case member even when the distal end portion of the irregular key pushes the contact wall of the plunger member. For this reason, the manipulable member maintains the locked state of the lock target. 
         [0017]    On the other hand, when the regular key is inserted into the plunger member, the key insertion holes disposed in the tumbler members engage with the concavo-tongue portions formed on the regular key. Thus, the tumbler members move in a direction where the state of engagement between the tongue portions and the recessed portions is released counter to the energizing force of the energizing members that energize the tumbler members such that the tongue portions engage with the recessed portions. 
         [0018]    Moreover, when the distal end portion of the regular key pushes the contact wall of the plunger member, just the plunger member moves inside the sleeve member. In this manner, just the plunger member moves, whereby the manipulable member releases the locked state of the lock target. 
         [0019]    Consequently, the locked state of the lock target can be released simply by a user inserting the regular key into the plunger member and pushing this regular key. For this reason, it is not necessary to load a force in the rotational direction on the key and the mechanical strength along the turning direction required of the key can be made small in comparison to a rotary lock device where manipulation of the lock mechanism is performed by rotating the key after inserting the key into the plunger. 
         [0020]    On the other hand, when the user tries to remove the regular key from the plunger member after releasing the locked state of the lock target, the state of engagement between the concavo-tongue portions formed on the regular key and the key insertion holes disposed in the tumbler members is maintained, and the plunger member moves and returns to its original position integrally with the removal of the regular key. 
         [0021]    At this time, in order for the tongue portions of the tumbler members to engage with recessed portions other than the recessed portions with which the tumbler members had been initially engaged and not obstruct the movement of the plunger member, the attachment pitch of the tumbler members must be made longer than the moving distance (stroke) of the plunger member. In other words, the length of the plunger member ends up becoming longer when the number of the tumbler members is increased in order to diversify the types of keys. 
         [0022]    However, in the present invention, the engagement positions where the tongue portions and the recessed portions engage with each other are arranged such that the engagement positions are offset in a thickness direction of the keys. For this reason, while the plunger member is being pushed, even when the regular key is removed from the plunger member and the tumbler members are returned to their initial positions by the energizing force of the energizing members, the tongue portions do not engage with recessed portions other than the recessed portions with which the tongue portions had initially been engaged. In other words, the length of the plunger member can be controlled from becoming longer even when the number of the tumbler members is increased. 
         [0023]    In the lock device of the above-described aspect of the present invention, there may be three of the engagement positions in the thickness direction of the keys. 
         [0024]    According to this configuration, there are three of the engagement positions in the thickness direction of the keys, so by creating three tumbler members whose tongue portions are offset, the length of the plunger member can be controlled from becoming longer even when the number of the tumbler members is increased. 
         [0025]    In the lock device of the above-described aspect of the present invention, the engagement positions may be arranged in a staggered manner in the thickness direction of the keys. 
         [0026]    According to this configuration, the engagement positions are arranged in a staggered manner in the thickness direction of the keys, so the tumbler members can be inverted and used, and the number of types of the tumbler members can be reduced. 
         [0027]    According to the lock device of the present invention, the lock device makes the mechanical strength required of the key small and controls the length of the plunger member from becoming longer even when the number of the tumbler members is increased. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1A  is a side sectional view showing the configuration of a lock device pertaining to a first embodiment of the invention, and  FIG. 1B  is a rear view showing the lock device pertaining to the first embodiment of the invention and shows a coupling rod and an actuating lever as seen from the rear; 
           [0029]      FIG. 2  is a side sectional view showing the configuration of the lock device pertaining to the first embodiment of the invention and shows a state where just a plunger member has moved to an actuated position; 
           [0030]      FIG. 3  is a side sectional view showing the configuration of the lock device pertaining to the first embodiment of the invention and shows a state where the plunger member and a sleeve member have moved to an actuated position; 
           [0031]      FIG. 4A  and  FIG. 4B  are sectional views showing the configuration of the lock device pertaining to the first embodiment of the invention and show a state where the lock device is cut on a plane of tumbler plates; 
           [0032]      FIG. 5A ,  FIG. 5B ,  FIG. 5C  and  FIG. 5D  are sectional views showing the configuration of the lock device pertaining to the first embodiment of the invention and show a state where the lock device is cut on the plane of the tumbler plate and the tumbler plates have moved; 
           [0033]      FIG. 6  is a perspective view showing the plunger member and the tumbler plates of the lock device pertaining to the first embodiment of the invention; 
           [0034]      FIG. 7  is a plan view showing the plunger member and the tumbler plates of the lock device pertaining to the first embodiment of the invention; 
           [0035]      FIG. 8  is a perspective view showing a key of the lock device pertaining to the first embodiment of the invention; and 
           [0036]      FIG. 9A  and  FIG. 9B  are sectional views showing the configuration of a lock device pertaining to a second embodiment of the invention and show a state where the lock device is cut on a plane of tumbler plates. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]    A lock device  10  pertaining to a first embodiment of the present invention will be described in accordance with  FIG. 1A  and  FIG. 1B  to  FIG. 8 . 
         [0038]    The lock device  10  of the present invention shown in  FIG. 1A  is disposed as part of a lock mechanism for locking and unlocking an open/close member, such as a door in an automobile, a trunk lid, or the lid of a glove box (lock target), and is used for a user to manipulate the lock mechanism (not shown) from a locked state to an unlocked state by a key  12 . 
         [0039]    A square cylinder-shaped case member  14  is disposed in the lock device  10  as an outer shell portion of the device. The case member  14  is formed so as to be long and narrow in an axial direction (direction of line S in the drawings) and, as shown in  FIG. 4A  and  FIG. 4B , has a substantially rectangular shape whose cross-sectional shape along a direction orthogonal to the axial direction of its peripheral wall portion (axis-orthogonal direction) is long in a height direction (direction of arrow H). Further, a lid portion  16  is formed in the case member  14  shown in  FIG. 1A  so as to close an opening on a distal end side (left side in  FIG. 1A ) of the case member  14  along the axial direction. A rectangular open portion  18 , into whose center portion the key  12  is insertable, is formed in the lid portion  16 . Moreover, a plate-shaped lever guide  20  that extends along the axial direction is integrally formed on the case member  14  on the lower end side of the rear end portion thereof. 
         [0040]    The case member  14  of the lock device  10  is disposed inside a door or the like in which the lock mechanism is housed, and the case member  14  is fixed such that the open portion  18  faces the outside from the inside of the door or the like. 
         [0041]    Moreover, the lock device  10  is disposed with a square cylinder-shaped sleeve member  22  that is disposed inside the case member  14 . The sleeve member  22  is formed so as to be long and narrow in the axial direction and has a substantially rectangular shape whose cross-sectional shape along the axis-orthogonal direction of its peripheral wall portion is long in the height direction. The sleeve member  22  is inserted into the inside of the case member  14  and is supported by the case member  14  so as to be movable between a standby position shown in  FIG. 1A  and an actuated position shown in  FIG. 3 . 
         [0042]    Further, the sleeve member  22  is configured such that its distal end surface contacts the inside of the lid portion  16  in a state where the sleeve member is in the standby position shown in  FIG. 1A  and such that the sleeve member  22  reaches the actuated position when the sleeve member  22  slides rearward a predetermined actuation stroke D (see  FIG. 3 ) from the standby position. 
         [0043]    Moreover, a plunger storage chamber  24  that is a space penetrating the sleeve member  22  in the axial direction is formed inside the sleeve member  22 . Further, in the axial direction intermediate portion of an outer peripheral surface of the sleeve member  22 , a step portion  26  is formed, a sleeve body  28  is formed on a distal end side via the step portion  26 , and a spring holding portion  30  is formed on a rear end side. 
         [0044]    The dimension of the spring holding portion  30  along the height direction (direction of arrow H in  FIG. 4A  and  FIG. 4B ) and a width direction (direction of arrow W in  FIG. 4A  and  FIG. 4B ) is smaller than that of the sleeve body  28 , and a coil spring  32  including a winding portion bent in a substantially rectangular shape is disposed on the outer peripheral side of the spring holding portion  30 . 
         [0045]    Further, a lid portion  34  is formed on the sleeve member  22  so as to close an opening on a rear end side of the lid portion  34 . A rod guide hole  36  that penetrates the lid portion  34  in the axial direction is formed in the center portion of the lid portion  34 . Moreover, a slide lever  38  that extends from the lower end portion of the lid portion  34  towards the rear end side along the axial direction is integrally formed on the sleeve member  22 . The lower end surface of the slide lever  38  is allowed to slidably contact the upper end surface of the lever guide  20  in the case member  14 . 
         [0046]    The outer peripheral surface of a cross-sectionally rectangular receiving member  40  that holds the rear end of the coil spring  32  is attached to the rear end portion of the case member  14 , and the inner peripheral surface of the receiving member  40  slidably contacts the outer peripheral surface of the spring holding portion  30 . Because of this configuration, the coil spring  32  is compressed and disposed between the step portion  26  of the sleeve member  22  and the receiving member  40 , and the coil spring  32  always energizes the sleeve member  22  into the standby position. 
         [0047]    Further, the lock device  10  is disposed with a plunger member  42  that is disposed inside the plunger storage chamber  24  of the sleeve member  22 . The plunger member  42  is formed in a substantially square column shape (see  FIG. 6 ) that is long and narrow in the axial direction, and the plunger member  42  is disposed with a plunger body  42 A that is inserted into the inside of the plunger storage chamber  24  on the distal end side and a plunger rod  42 B that projects in the axial direction from the rear end surface of the plunger body  42 A. 
         [0048]    The plunger body  42 A is slidably inserted into the inside of the plunger storage chamber  24  and is supported by the case member  14  via the sleeve member  22  so as to be movable between a predetermined standby position (see  FIG. 1A ) and an actuated position (see  FIG. 3 ). 
         [0049]    The distal end surface of the plunger member  42  contacts the inside of the lid portion  16  in a state where the plunger member  42  is in the standby position, and the plunger member  42  reaches the actuated position when the plunger member  42  slides rearward the predetermined actuation stroke D (see  FIG. 2  and  FIG. 3 ) from the standby position. The details of the stroke D will be described later. 
         [0050]    Moreover, the rear end side of the plunger rod  42 B of the plunger member  42  projects to the outside of the sleeve member  22  through the rod guide hole  36  in the sleeve member  22 . Further, the lower end surface of the plunger rob  42 B projecting from the rod guide hole  36  slidably contacts, in the axial direction, the upper end surface of the slide lever  38 . 
         [0051]    Moreover, a key hole  48  disposed along the axial direction is formed in the central portion of the plunger body  42 A, and the cross-sectional shape of the key hole  48  has a rectangular shape that is long and narrow along the height direction of the lock device  10 . The cross-sectional shape of the key hole  48  corresponds to the shape of the key  12  that corresponds to the specifications of the lock device  10  pertaining to the present embodiment, and the key  12  is configured to be insertable into and removable from the key hole  48 . 
         [0052]    As shown in  FIG. 8 , the portion of the key  12  that is inserted into the key hole  48  is formed in a long and narrow plate shape and is manufactured using a material such as metal, resin, paper, or a composite material of these, for example. Further, an insertion guide portion  50  whose thickness becomes thinner in a sloping manner from its proximal end side towards its distal end side is formed on the distal end portion of the key  12 . 
         [0053]    Moreover, one end surface and the other end surface of the key  12  along a direction orthogonal to the longitudinal direction thereof are configured as an upper engaging end  52  and a lower engaging end  54 . The key  12  is inserted by a user into the key hole  48  with an orientation where the upper engaging end  52  faces up along the height direction of the device. 
         [0054]    Further, six engagement positions PE 1  to PE 6  that are mutually different along the longitudinal direction of the key  12  (axial direction of the device) are disposed on the upper engaging end  52  and the lower engaging end  54  of the key  12 , and upper engaged portion  58  and lower engaged portions  60  that are selectively recessed in “V” shapes are disposed in the engagement positions PE 1  to PE 6 . 
         [0055]    Further, as shown in  FIG. 1A , plural (six in the present embodiment) tumbler storage chambers  120 ,  122 ,  124 ,  126 ,  128  and  130  are formed as slits in the plunger body  42 A. The tumbler storage chambers  120 ,  122 ,  124 ,  126 ,  128  and  130  are arrayed at a substantially equal pitch along the axial direction, and this pitch is substantially equal to the pitch of the six engagement positions PE 1  to PE 6  of the key  12  (see  FIG. 4A  and  FIG. 4B ). 
         [0056]    Moreover, an upper end open portion  42 C and a lower end open portion  42 D (see  FIG. 4A  and  FIG. 4B ) are disposed in the upper end portion and the lower end portion of each of the tumbler storage chambers  120 ,  122 ,  124 ,  126 ,  128  and  130 , and tumbler plates  66  and  68  that are substantially tabular members are disposed inside the tumbler storage chambers  120 ,  122 ,  124 ,  126 ,  128  and  130 . Here, an attachment pitch P of the tumbler plates  66  and  68  is set to be larger than half of the stroke D of the aforementioned plunger member  42  from the standby position to the actuated position. The details of the relationship between the attachment pitch and the stroke D will be described later. 
         [0057]    Further, as shown in  FIG. 4A , the tumbler plates  66  are disposed so as to be movable along the height direction inside the tumbler storage chambers  122 ,  126  and  130  that are disposed in the even number places from the distal end portion. Engaging tongue portions  66 A that protrude from one side (the left side shown in  FIG. 4A ) of the upper surface of the plunger member  42  and engage with engaging recessed portions  62  disposed in the sleeve member  22  are disposed on the upper end portions of the tumbler plates  66 . 
         [0058]    Moreover, projecting portions  66 B that project from the other side (the right side shown in  FIG. 4A ) of the lower surface of the plunger member  42  and engage with meshing recessed portions  74  disposed in the sleeve member  22  when the tumbler plates  66  move downward are disposed on the lower end portions of the tumbler plates  66 . Further, rectangular key insertion holes  66 C that extend up and down are disposed in the center portions of the tumbler plates  66 , and the key insertion holes  66 C are communicated with the key hole  48  (see  FIG. 1A ). 
         [0059]    As shown in  FIG. 4B , the tumbler plates  68  are disposed so as to be movable along the height direction inside the tumbler storage chambers  120 ,  124  and  128  that are disposed in the odd number places from the distal end portion. Engaging tongue portions  68 A that protrude from one side (the right side shown in  FIG. 4B ) of the upper surface of the plunger member  42  and engage with the engaging recessed portions  62  disposed in the sleeve member  22  are disposed on the upper end portions of the tumbler plates  68 . Projecting portions  68 B that project from the other side (the left side shown in  FIG. 4A ) of the lower surface of the plunger member  42  and engage with the meshing recessed portions  74  disposed in the sleeve member  22  when the tumbler plates  68  move downward are disposed on the lower end portions of the tumbler plates  68 . Further, rectangular key insertion holes  68 C that extend up and down are disposed in the center portions of the tumbler plates  68 , and the key insertion holes  66 C are communicated with the key hole  48  (see  FIG. 1A ). 
         [0060]    Moreover, coil springs  72  that energize the tumbler plates  66  and  68  upward are disposed in the tumbler storage chambers  120 ,  122 ,  124 ,  126 ,  128  and  130 , and in a state where the key  12  (see  FIG. 1A ) is not inserted into the key hole  48  (see  FIG. 1A ), the engaging tongue portions  66 A and  68 A disposed on the upper ends of the tumbler plates  66  and  68  are energized by the coil springs  72  and engage with the engaging recessed portions  62  of the sleeve member  22 . 
         [0061]    In this state, as shown in  FIG. 6  and  FIG. 7 , the engaging tongue portions  66 A and the engaging tongue portions  68 A are arranged in a staggered manner as a result of being offset in the thickness direction of the key. In other words, engagement positions  46  between the engaging tongue portions  66 A and  68 A and the engaging recessed portions  62  shown in  FIG. 4A  and  FIG. 4B  are also arranged in a staggered manner in the thickness direction of the key. It will be noted that in  FIG. 6 , the sleeve member  22  and the like are omitted in order to make it easier to understand the arranged state of the engaging tongue portions  66 A and  68 A. 
         [0062]    As shown in  FIG. 1A , the lock device  10  is configured such that, when the key  12  is inserted into the key hole  48  in the plunger member  42  in the standby position, the key  12  passes through the key insertion holes  66 C and  68 C in the tumbler plates  66  and  68 , the upper edge portions or the lower edge portions of the key insertion holes  66 C and  68 C in the tumbler plates  66  and  68  engage with the upper engaged portions  58  or the lower engaged portions  60  (see  FIG. 8 ) of the key  12 , and the tumbler plates  66  and  68  move in the height direction counter to the energizing force of the coil springs  72 . 
         [0063]    Consequently, the lock device  10  is configured such that, when the key  12  is inserted into the key hole  48 , the six tumbler plates  66  and  68  move along the height direction (sliding direction) to positions corresponding to the upper engaged portions  58  and the lower engaged portions  60  of the key  12 . Here, a key code for unlocking the lock device  10  is imparted beforehand to the lock device  10 , and the shapes (depths) of the upper engaged portions  58  and the lower engaged portions  60  that become the engagement partners of the tumbler plates  66  and  68  are set in accordance with the key code. 
         [0064]    As long as the key  12  is suited to the specifications of the lock device  10  pertaining to the present embodiment, the key  12  is insertable into and removable from the key hole  48 , but as the key  12 , there is one where the shapes of all of its upper engaged portions  58  and its lower engaged portions  60  that become the engagement partners of the tumbler plates  66  and  68  correspond to the key code (this will be called a “regular key  12 R” below) and one whose shape does not correspond to the key code and does not match that of the regular key  12 R (this will be called an “irregular key  121 ” below). 
         [0065]    When the regular key  12 R is inserted into the key hole  48 , the six tumbler plates  66  and  68  move to regular positions corresponding to the upper engaged portions  58  and the lower engaged portions  60  such that the state of engagement between the engaging tongue portions  66 A and  68 A and the engaging recessed portions  62  is released. 
         [0066]    In other words, all of the tumbler plates  66  and  68  move downward such that the engaging tongue portions  66 A and  68 A move away from the engaging recessed portions  62 , and the tumbler plates  66  and  68  move to the regular positions shown in  FIG. 5A  and  FIG. 5B . At this time, moreover, as shown in  FIG. 5C  and  FIG. 5D , the tumbler plates  66  and  68  do not move too far downward and the projecting portions  66 B and  68 B of the tumbler plates  66  and  68  do not engage with the meshing recessed portions  74 . 
         [0067]    In this manner, when all of the tumbler plates  66  and  68  move to the regular positions, the engagement between the sleeve member  22  and the plunger member  42  is released, and when the normal key  12 R is pushed further in the axial direction, the distal end portion of the normal key  12 R pushes a contact wall  42 E formed in the bottom of the plunger member, the sleeve member  22  is restrained in the standby position by a later-described locking bar  108  as shown in  FIG. 2 , and just the plunger member  42  slides inside the sleeve member  22  and moves to the actuated position. 
         [0068]    Further, the lock device  10  is configured such that, when the irregular key  121  is inserted into the key hole  48  shown in  FIG. 1A , the tumbler plates  66  and  68  moves to positions corresponding to the upper engaged portions  58  and the lower engaged portions  60  (see  FIG. 8 ) of the key  12 , and at least one of the tumbler plates  66  and  68  moves to an irregular position, so the state of engagement between the engaging tongue portions  66 A and  68 A and the engaging recessed portions  62  is maintained, or the projecting portions  66 B and  68 B and the meshing recessed portions  74  engage with each other. 
         [0069]    In this manner, when at least one of the tumbler plates  66  and  68  moves to an irregular position, the state of engagement between the sleeve member  22  and the plunger member  42  is not released, and when the irregular key  121  is further pushed in the axial direction, as shown in  FIG. 3 , the later-described locking bar  108  is held in a storage hole  106 , and the plunger member  42  slides inside the case member  14  counter to the energizing force of the coil spring  32  together with the sleeve member  22  and moves to the actuated position. 
         [0070]    As shown in  FIG. 1A , a plate-shaped actuating lever  92  that is coupled to the rear end portion of the plunger rod  42 B and coupled to the end portion of the slide lever  38  is disposed in the lock device  10 , and the actuating lever  92  is bent in a substantial “L” shape. 
         [0071]    A slot-like coupling hole  94  that is long in the longitudinal direction is formed in a proximal end portion (in  FIG. 1A , the lower end portion) of the actuating lever  92 . Further, a circular column-shaped coupling shaft  96  whose axial direction is in the width direction of the device is disposed in the slide lever  38 , and the coupling shaft  96  is inserted into the coupling hole  94  in the actuating lever  92  and configured to be movable along the longitudinal direction of the coupling hole  94 . Thus, the actuating lever  92  is swingably coupled to the slide lever  38 . 
         [0072]    Further, a circular column-shaped pushing shaft  98  whose axial direction is in the width direction is disposed in the rear end portion of the plunger rod  42 B. The pushing shaft  98  penetrates a corner portion of the L-shaped actuating lever  92  and is rotatably coupled to the actuating lever  92 . 
         [0073]    Moreover, the distal end of the actuating lever  92  is disposed so as to extend rearward from the pushing shaft  98 , and a circular cylinder-shaped bearing member  118  is attached to the distal end portion of the actuating lever  92 . Further, an upper end portion of a long and narrow round bar-shaped coupling rod  100 , which upper end portion is bent in an “L” shape, is rotatably coupled to the bearing member  118 . Moreover, the coupling rod  100  is disposed so as to extend along the height direction, and the lower end portion of the coupling rod  100  is coupled to the lock mechanism (not shown). 
         [0074]    Because of this configuration, the actuating lever  92  is disposed so as to be swingable between a predetermined locked position (see  FIG. 1A ) and an unlocked position (see  FIG. 2 ) about the coupling shaft  96  of the slide lever  38 . 
         [0075]    It will be noted that the positions of the coupling shaft  96  and the pushing shaft  98  are set such that, as shown in  FIG. 1A , in a state where the sleeve member  22  and the plunger member  42  are in the standby positions, the actuating lever  92  is held in the locked position, and as shown in  FIG. 2 , in a state where the sleeve member  22  is in the standby position and just the plunger member  42  has moved the stroke D from the standby position to the actuated position, the actuating lever  92  swings to the unlocked position. 
         [0076]    In this manner, when the actuating lever  92  swings from the locked position to the unlocked position, it causes the coupling rod  100  to move downward and transmit pushing force (manipulating force) to the lock mechanism via the coupling rod  100 . When the lock mechanism receives this operating force, it changes from a locked state to an unlocked state to enable an open/close member such as a door, a trunk lid, or the lid of a glove box that had been locked by the lock mechanism to be opened. 
         [0077]    As shown in  FIG. 3 , when the sleeve member  22  and the plunger member  42  integrally move from the standby positions to the actuated positions, the relative positional relationship between the pushing shaft  98  and the coupling shaft  96  does not change, so the actuating lever  92  is held in the locked position. Consequently, the lock device is maintained in the locked state and is not unlocked. In this state, when the user stops pushing the key  12  (in this case, a key whose shape is different from that of the regular key  12 R), the sleeve member  22  and the plunger member  42  in the actuated positions are returned to the standby positions by the energizing force of the coil spring  32 . 
         [0078]    Further, as shown in  FIG. 1A , a recessed inner peripheral locking hole  102  is formed in the upper end portion and the lower end portion of the outer peripheral surface of the plunger body  42 A, and a recessed outer peripheral locking hole  104  is formed in the upper end portion and the lower end portion of the inner peripheral surface of the case member  14 . The inner peripheral locking hole  102  is disposed on the rear end side of the tumbler plates  66 , and the outer peripheral locking hole  104  is disposed so as to be in the same position as the inner peripheral locking hole  102  along the axial direction and the width direction of the device when the plunger member  42  is in the standby position. 
         [0079]    Moreover, the storage hole  106  is formed in the sleeve member  22  so as to penetrate the sleeve member  22  along the axis-orthogonal direction. The storage hole  106  is disposed so as to be in the same position as the outer peripheral locking hole  104  and the inner peripheral locking hole  102  along the axial direction and the width direction in a state where the sleeve member  22  and the plunger member  42  are in the standby positions. Further, the cross-sectional shapes along the axial direction of the outer peripheral locking hole  104 , the inner peripheral locking hole  102  and the storage hole  106  match each other. 
         [0080]    Moreover, the substantially square column-shaped locking bar  108  is stored, so as to be slidable along the axis-orthogonal direction, inside the storage hole  106 , and an energizing plate  110  and a spring  112  are inserted into the outer peripheral locking hole  104 . The outer peripheral side of the locking bar  108  is configured as a flat surface whose end surface is parallel to the axial direction, and the distal end surface of the locking bar  108  is configured as a flat cam surface  116  that slants towards the outer peripheral side from the rear end along the axial direction towards the distal end. 
         [0081]    Moreover, the locking bar  108  is configured such that its rear end portion is insertable into and removable from the outer peripheral locking hole  104  in state where its rear end surface is caused to pressingly contact the plate-shaped energizing plate  110  when the sleeve member  22  is in the standby position. Further, when the sleeve member  22  and the plunger member  42  are in the same position along the axial direction, the distal end portion of the locking bar  108  is removably inserted into the inner peripheral locking hole  102  and caused to pressingly contact the bottom surface portion of the inner peripheral locking hole  102 . The energizing plate  110  is slidably inserted into the outer peripheral locking hole  104 , and the spring  112  is disposed in a compressed state between the energizing plate  110  and the bottom surface portion of the outer peripheral locking hole  104 . 
         [0082]    When the regular key  12 R is inserted into the key hole  48  and the plunger member  42  starts moving from the standby position to the actuated position, the cam surface  116  of the locking bar  108  receives a partial force (pushing force) along the axis-orthogonal direction from the outer peripheral surface of the plunger member  42 , whereby the locking bar  108  is pushed out towards the outer peripheral side counter to the energizing force of the spring  112 . Thus, as shown in  FIG. 2 , the rear end portion of the locking bar  108  is inserted into the outer peripheral locking hole  104 . At this time, the locking bar  108  is disposed so as to straddle the boundary between the outer peripheral locking hole  104  and the storage hole  106 , so the locking bar  108  restrains the sleeve member  22  in the standby position. Further, when the plunger member  42  that has moved to the actuated position returns to the standby position, as shown in  FIG. 1 , the locking bar  108  is moved towards the inner peripheral side by the energizing force of the spring  112  such that the distal end portion of the locking bar  108  is inserted into the inner peripheral locking hole  102 . 
         [0083]    Further, in a state where the irregular key  121  whose shape is different from that of the regular key  12 R is inserted into the key hole  48  and the plunger member  42  is coupled to the sleeve member  22  by the tumbler plates  66  and  68 , as shown in  FIG. 3 , the locking bar  108  moves in the axial direction integrally with the sleeve member  22  and the plunger member  42  while being held in the storage hole  106  and the inner peripheral locking hole  102 . 
         [0084]    Next, the action of the lock device  10  according to this configuration will be described. 
         [0085]    When the user inserts the irregular key  121  whose shape is different from that of the regular key  12 R into the key hole  48  shown in  FIG. 1A , the tumbler plates  66  and  68  move to positions corresponding to the upper engaged portions  58  and the lower engaged portions  60  of the irregular key  121 , and the state of engagement between the engaging tongue portions  66 A and  68 A of at least one of the tumbler plates  66  and  68  and the engaging recessed portions  62  is maintained (see  FIG. 4A  and  FIG. 4B ), or the projecting portions  66 B and  68 B become engaged with the meshing recessed portions  74  and the state of engagement between the sleeve member  22  and the plunger member  74  is maintained. 
         [0086]    Moreover, when the user pushes the irregular key  121  in the axial direction, as shown in  FIG. 3 , the plunger member  42  and the sleeve member  22  integrally move the stroke D from the standby positions to the actuated positions. 
         [0087]    The actuating lever  92  in the locked position does not swing even when the plunger member  42  and the sleeve member  22  integrally reach the actuated positions, so the locked state of the lock mechanism is maintained. Thereafter, when the user stops pushing the irregular key  121 , the plunger member  42  and the sleeve member  22  are integrally returned to the standby positions by the energizing force of the coil spring  32 . 
         [0088]    On the other hand, when the user inserts the regular key  12 R into the key hole  48  shown in  FIG. 1A , the tumbler plates  66  and  68  move to the regular positions (see  FIG. 5A  and  FIG. 5B ) corresponding to the upper engaged portions  58  and the lower engaged portions  60  of the regular key  12 R, and the state of engagement between the sleeve member  22  and the plunger member  42  is released. 
         [0089]    Moreover, when the user pushes the regular key  12 R in the axial direction, as shown in  FIG. 2 , just the plunger member  42  moves the stroke D from the standby position to the actuated position in a state where the sleeve member  22  is restrained in the standby position by the locking bar  108  whose cam surface  116  has been pushed out. 
         [0090]    When just the plunger member  42  reaches the actuated position, the actuating lever  92  swings to the unlocked position, pushes the coupling rod  100  down, and unlocks the lock mechanism that had been locked. Thus, the open/close member that had been locked by the lock mechanism is unlocked and becomes capable of being opened. 
         [0091]    Thereafter, when the uses removes the regular key  12 R from the plunger member  42 , the state of engagement between the upper engaged portions  58  and the lower engaged portions  60  formed on the regular key  12 R and the key insertion holes  66 C and  68 C disposed in the tumbler plates  66  and  68  is maintained, and the plunger member  42  returns to the standby position integrally with the removal of the regular key  12 R. 
         [0092]    Here, as mentioned before, the attachment pitch P of the tumbler plates  66  and  68  is set to be larger than half of the stroke D. Moreover, as shown in  FIG. 4A ,  FIG. 4B  and  FIG. 6 , the engagement positions  46  are arranged in a staggered manner in the thickness direction of the key. 
         [0093]    For this reason, even when the user removes the regular key  12 R from the key hole  48  in the actuated position of the plunger member  42  shown in  FIG. 2  and the tumbler plates  66  and  68  are energized upward by the energizing force of the coil springs  72  (see  FIG. 4A  and  FIG. 4B ), the engaging tongue portions  66 A and  68 A do not engage with other engaging recessed portions  62  other than the engaging recessed portions  62  with which they engage when disposed in the standby position. In other words, they do not obstruct the return of the plunger member  42  to the standby position. 
         [0094]    That is, because the attachment pitch P of the tumbler plates  66  and  68  is set to be larger than half of the stroke D, the tumbler plates  66  and  68  are configured to stop before they reach the engaging recessed portions  62  disposed on the same axial line even when the plunger  42  is moved to the actuated position. 
         [0095]    When the engagement positions  46  are not offset in the thickness direction of the key, the engaging tongue portions  66 A and  68 A engage with other engaging recessed portions  62  and obstruct the return of the plunger member  42  to the standby position, so the attachment pitch P of the tumbler plates  66  and  68  must be set to be larger than the stroke D. For that reason, the lock device  10  must be made long in the axial direction in order to ensure the predetermined stroke D. 
         [0096]    However, by staggering the engagement positions  46  in the thickness direction of the key as in the present embodiment, it suffices for the attachment pitch P of the tumbler plates  66  and  68  to be set to be larger than half of the stroke D, so that even when the number of the tumbler plates  66  and  68  is increased in order to diversify the types of the key  12 , the length of the plunger member  42  can be controlled from becoming longer. 
         [0097]    Further, the user inserts the key  12  into the key hole  48  and pushes the key  12  along the axial direction of the device; thus, when the key  12  is the regular key  12 R, the lock mechanism can be unlocked, and when the key  12  is the irregular key  121 , the lock mechanism can be maintained in a locked state. Therefore, it is not necessary for rotational torque to be transmitted by the key  12  during key manipulation by the user in comparison to a rotary lock device where manipulation with respect to a manipulated device is performed by rotating the key after inserting the key into the key insertion hole, and just a load along the axial direction acts on the key  12 , so the mechanical strength along the turning direction required of the key  12  can be made sufficiently small. 
         [0098]    Further, because the mechanical strength can be made small, it becomes unnecessary for the key  12  to invariably be manufactured by a high-strength material such as iron or stainless steel, and the key  12  can be manufactured by a low-strength material whose use as a conventional material had been difficult, such as plastic, paper to which a waterproof treatment has been administered, an aluminum alloy, or a magnesium alloy, for example. Further, even when the thickness of the key  12  is made significantly thinner in comparison to that of a conventional key, problems such as deformation do not arise. 
         [0099]    Further, even when the irregular key  121  including a driver or the like is inserted into the key hole  48  and pushed to the actuated position, the lock mechanism does not become unlocked simply by the plunger member  42  and the sleeve member  22  integrally moving from the standby positions to the actuated positions. Moreover, unreasonable force does not act on the configural parts such as the case member  14 , the sleeve member  22 , the plunger member  42 , and the tumbler plates  66  and  68  disposed in these, so damage to these configural parts can be effectively prevented. 
         [0100]    Next, a second embodiment of the lock device  10  of the present invention will be described in accordance with  FIG. 9A  and  FIG. 9B . 
         [0101]    It will be noted that the same reference numerals will be given to members that are the same as those in the first embodiment, and that description of those same members will be omitted. As shown in  FIG. 9A  and  FIG. 9B , in this embodiment, in contrast to the first embodiment, not only are the engaging tongue portions  66 A and  68 A disposed on the upper ends of the tumbler plates  66  and  68 , but engaging tongue portions  80 A and  82 A are also disposed on the lower ends of tumbler plates  80  and  82 . 
         [0102]    Specifically, the tumbler plates  66  disposed with the engaging tongue portions  66 A on one side of their upper ends (see  FIG. 4A ) are disposed inside the tumbler storage chambers  120  and  128 , the tumbler plates  68  disposed with the engaging tongue portions  68 A on the other side of their upper ends (see  FIG. 4B ) are disposed inside the tumbler storage chambers  122  and  130 , a tumbler plate  80  disposed with the engaging tongue portion  80 A on one side of its lower end (see  FIG. 9A ) is disposed inside the tumbler storage chamber  124 , and the tumbler plate  82  disposed with the engaging tongue portion  82 A on the other side of its lower end is disposed inside the tumbler storage chamber  126  (see  FIG. 9B ). 
         [0103]    In this manner, by disposing the engagement positions  46  configured by the engaging tongue portions  80 A and  82 A and the engaging recessed portions  62  also on the lower side of the plunger member  42 , the number of key codes can be increased.