Abstract:
A vehicle seat lock device is provided. The vehicle seat lock device includes a seat lock housing, a striker, a hook member and a blocking member. The seat lock housing is configured to be fixed to one of a seat back and a vehicle body. The striker is configured to be fixed to the other of the seat back and the vehicle body. The hook member is rotatably mounted on the seat lock housing to latch and unlatch the striker by engaging and disengaging the striker, respectively. The blocking member is pivotally mounted on the seat lock housing. The blocking member pivots and contacts with the hook member to prevent the hook member from rotating and to maintain engagement between the hook member and the striker when a load that is higher than a predetermined amount is inputted to the vehicle body.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of application Ser. No. 12/951,940, filed on Nov. 22, 2010, which is entitled to benefit of, under 35 U.S.C. §119(e), U.S. provisional applications Ser. Nos. 61/263,108, 61/263,118 and 61/263,122 filed on Nov. 20, 2009, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to a lock device for a vehicle retractable seat whose seat back is able to be secured to and released from a vehicle body selectively. In particular, this technology relates to a locking mechanism for locking between a member connected to a vehicle body and a member connected to a seat back when a dynamic force, which is greater than a holding force by a latch mechanism in ordinary use by user, is inputted to the vehicle body. 
     2. Description of Related Art 
     A vehicle seat attachment latch assembly is disclosed in, for example, U.S. Pat. No. 6,945,585. This latch assembly includes a latch mounted for movement between latched and unlatched positions with respect to a striker to secure and selectively release a vehicle seat with respect to a vehicle body. A latching wedge is mounted on the latch for movement therewith and for movement with respect thereto in cooperation with a bias provided by a first spring that moves a wedging surface of the latching wedge into wedging contact with the striker with the latch in its latched position in order to provide a rattle free attachment. A locking pawl and a spring cooperate to hold the latch in its latched position or permit release thereof for movement to the unlatched position where the striker is released. That is to say, the latch (member) engages with locking pawl every time when the latch member latches or holds the striker, in ordinary use by user. 
     As described above, according to the latch assembly in U.S. Pat. No. 6,945,585, to eliminate play between the latch member and the striker which causes a rattle, has an additional latching wedge and the bias (spring) on the latch member, for purpose of holding the striker being tightly with the latch member when the striker is positioned at a latched position. Thus, this structure requires additional members, to add a locking function/mechanism into a latching function/mechanism. 
     Meanwhile, U.S. Pat. No. 5,730,480 discloses a lock device for a retractable automotive seat that includes a base member having a striker receiving slot into which the striker can be led. A latch plate is pivotally connected to the base member. A locking plate is pivotally connected to the base member. A striker restraining member is pivotally connected through a pivot shaft to the base member. The striker restraining member is pivotal between a restraining position, where a contact edge thereof abuts against the striker, and a releasing position, where the contact edge disengages from the striker. Springs are employed for biasing the latch plate to pivot toward a stand-by position, biasing the locking plate to pivot toward a lock position, and biasing the striker restraining member to pivot toward the restraining position. A link mechanism is employed for causing the striker restraining member to take the restraining position when the latch plate and the locking plate take latching and lock positions respectively. The pivot shaft of the striker restraining member is positioned at the back of the striker receiving slot, so that the contact edge of the striker restraining member can abut against a front side of the striker. In other words, a locking mechanism including the locking plate, the latch plate and so forth is sandwiched by the base member and another plate. 
     As described above, according to the lock device in U.S. Pat. No. 5,730,480, as in  FIG. 2  two plate members sandwich a locking structure/mechanism such as the locking plate, the latch plate and so forth. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present disclosure, the vehicle seat lock device includes a seat lock housing, a striker, a hook member, and a blocking member. The seat lock housing is fixed to or configured to be fixed to one of a seat back or a vehicle body and the striker is fixed to or applied to be fixed to the other one of the seat back or the vehicle body. Furthermore, the hook member is rotatably mounted on the seat lock housing for latching and unlatching the striker by engaging and disengaging the striker, and the blocking member is pivotally mounted on the seat lock housing, so that the blocking member is able to pivot and contact with the hook member for preventing the hook member from its rotation, to keep the engagement between the hook member and the striker while higher load than predetermined is inputted to the vehicle body. 
     In this exemplary aspect, the hook member is able to be integrally formed with the wedge portion that latches and holds the striker with the holding force, in the latched position, since the hook member does not contact with the block member while latching and unlatching the striker as an ordinary operation. This holding force is able to work in the opposite direction to the direction in which the striker moves to unlatched position, for purpose of eliminating the play and the rattle between the wedge portion of the hook member and the striker. By adjusting the angle of the wedge portion, the hook member is able to keep the engagement between the hook member and the striker properly in the latched position, while the load applied to the hook member and the striker is the predetermined range which corresponds to ordinary use force amount by a passenger such as seating, lean over and hanging something. Meanwhile, when higher or dynamic load, caused from i.e. vehicle collision or unexpected braking acceleration, is inputted or generated at vehicle body and then transmitted to the seat lock device, the hook member can be rotated to unlatch the striker due to the higher load than predetermined. However, in this configuration, the block member pivots to contact with the hook member so as to stop rotating as locking. In this way, with a fewer components structure, the block member is able to maintain the engagement of the hook member and the striker, namely a latched state. 
     According to another aspect of the present invention, the vehicle seat lock device includes the base plate fixed to or configured to be fixed to one of a seat back or a vehicle body, and the deformable striker pin fixed to the base plate and engaging in a hole provided with the other one of the seat back or the vehicle body in predetermined clearance. With this structure, while higher load than predetermined is inputted to the vehicle body, the deformable striker pin contacts with the hole and transmits the load which is inputted in the vehicle body, from the vehicle body to the seat back. 
     In this example, the latch and lock mechanism is made and mounted on only the base plate, and the deformable striker pin works as the striker for the latch mechanism and as energy absorbing and transmission member for the lock mechanism. That is to say, with the fewer components, the light weight and effective latch and lock mechanism is provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view illustrating a vehicle seat lock device and a seat assembled with the seat lock device, according to one embodiment; 
         FIG. 2  is a perspective view illustrating the seat lock device seen from direction “A” in  FIG. 1 ; 
         FIG. 3  is a perspective view illustrating the seat lock device in working state; 
         FIG. 4  is a perspective view illustrating the seat lock device in lock state; 
         FIG. 5  is a perspective view illustrating the symmetrical device of the seat lock device; 
         FIG. 6  is a side view illustrating the lock device of a second embodiment; 
         FIG. 7  is a plane view illustrating the lock device, ordinary use state and working state, seen from direction “B” in  FIG. 6 ; 
         FIG. 8  is a side view illustrating the lock device of another example of the second embodiment; and 
         FIG. 9  is a side view illustrating the lock device of another example of the second embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views. 
     Embodiments of a vehicle seat lock device  1  for a seat of an automotive vehicle will be described hereinafter with reference to attached  FIGS. 1 to 9 . Herein, the vehicle seat lock device  1  is mounted on a seat back  3  of a rear seat  2  in the automotive vehicle. The first embodiment is explained with reference to  FIG. 1  through  FIG. 5 . 
       FIG. 1  illustrates the vehicle seat lock device  1  for the seat  2  in the automotive vehicle (hereinafter, referred to also as seat lock device  1 ). According to the first embodiment, the lock device  1  includes a seat lock housing  11  and a striker  4 . The seat lock housing  11  is mounted to a side surface of the seat back  3  of the retractable seat  2 . The striker  4  is mounted to a side surface of a vehicle body  7  at a position corresponding to the seat lock housing  11  in a state where the seat back  3  is in an upright position (illustrated in continuous lines). This state, where the seat back  3  is secured to the side surface of the vehicle body  7 , is termed the “latched state.” 
     The latched state of the vehicle seat lock device  1  is changed to an unlatched state  3   a  (shown in dotted lines) by pulling a wire  6  which is assembled to the seat lock device  1 , thereby causing the seat back  3  of the seat  2  to fold towards a seat cushion  8 . In  FIG. 1 , the folded seat back  3   a , the seat lock housing  11  mounted to the seat back  3   a  and the wire  6  (i.e., a unlatched state of the lock device  1 ) are indicated by dotted lines. A is readily apparent to one of ordinary skill in the art, although not illustrated in the drawings, the seat lock housing  11  of the vehicle lock device  1  is able to be mounted on the vehicle body  7 , while striker  4  can be mounted on the side surface of a seat back  3 . 
       FIG. 2  is a view from direction “A” in  FIG. 1 . The seat lock device  1  includes, in the seat lock housing  11 , a hook member  12 , a block member  13  and the striker  4  which is fixed on the vehicle body  7 . The seat lock housing  11  has a hole  11   a  and a hole  11   b  at upper and bottom flanges, and is mounted on the side of the seat back  3  via these holes  11   a ,  11   b.    
     The hook member  12  is integrally formed with an engagement portion  12   a  at one end and a slit hole  12   d  on an opposite end. The engagement portion  12   a  is formed by a incline portion  12   f  that mates with the striker  4 , a wedge portion  12   b  that engages with the striker  4  and a dent portion  12  that is able to hook and hold the striker  4  in the latched state. When the striker  4  moves from the unlatched position to a latched position, the striker  4  makes contact with the incline portion  12   f  of hook member  12 , and this contact causes the hook member  12  to rotate counter-clockwise, due to a tapered shape of the incline portion  12   f . The striker  4  then enters into the dent portion  12   e . Once this occurs, the hook member  12  rotates clockwise back in to the latched position. A rotation axis member  12   c  of the hook member  12  is located between the engagement portion  12   a  and the slit hole  12   d , so that the hook member  12  is rotatable about the rotation axis, the rotational pin  12   c . A spiral spring  15  is disposed around the rotational axis member, rotational pin  12   c . The spiral spring  15  biases the hook member  12  in the direction toward the latched state, namely clockwise direction, by its torsional spring force. A user&#39;s operational load transmitted from handle leveler (not shown) to the slit hole  12   d  via the wire  6  rotates the hook member  12  in the direction toward the unlatched state, namely counter-clockwise direction. In this way, under an ordinary operation by a user, the seat lock device  1  latches and unlatches, engages and disengages with the striker  4  at an angle range a of the hook member  12  rotation. 
     The block member  13  has a pendulum shape. One end of the block member  13  has a contact portion  13   a , and the opposite end has a pivot axis  13   b . A torsion spring, which acts as a bias spring  14  is disposed at the pivot axis member, the pivot pin  13   b . One end  14   a  of the bias spring  14  is hooked on the seat lock housing  11 , and the other end  14   b  is hooked on the block member  13 . The torsional force of the bias spring  14  biases the block member  13  to a standby position shown in  FIG. 2 , namely counter-clockwise, where the block member  13  has no contact with the hook member  12  during either latched or unlatched states during ordinary operation of the hook member  12 , which corresponds to a state that a static or a quasi static load inputted to the vehicle body  7 . That is to say, the hook member  12  is able to be integrally formed with the wedge portion  12   b  that latches and holds the striker  4  with the holding force, in the latched position, since the hook member  12  does not contact with the block member  13  while latching and unlatching the striker  4  during an ordinary operation. 
     This holding force of the hook member  12  in the latched state is able to work in the opposite direction to the direction in which the striker moves  4  to unlatched position, for the purpose of eliminating the play and the rattle between the wedge portion  12   b  of the hook member  12  and the striker  4 . By adjusting the angle of the wedge portion  12   b , the hook member  13  is able to keep the engagement between the hook member  12  and the striker  4  properly in the latched position. The load applied to the hook member  12  and the striker  4  is a predetermined range which corresponds to an ordinary force amount used by a passenger due to as sitting, lean over and hanging something. 
     In  FIG. 3 , the seat lock device  1  is in working state where a higher load than the predetermined range is input to vehicle body  7 , namely higher acceleration than predetermined happens. This high loading happens or is caused by, for example, a vehicle collision or a severe acceleration change. During such loading, the striker  4 , that is fixed to the vehicle body  7 , would move toward the unlatched position  4   a  relative to the seat lock housing  11 , which is fixed to the seat back  3 , since the vehicle body  7  reacts more quickly than the vehicle seat  2  and a passenger relatively, in response to such a dynamic load. Also, at the moment of the high loading, the block member  13  starts to rotate counter-clockwise due to inertia force of the block member  13 . In particular, the torsional force of the bias spring  14  is less than the inertial force generated during the dynamic force input situation. 
     The weight of the blocking member  13  is designed so that enough inertial force is generated to cause the blocking member  13  to rotate clockwise during the high loading. Thus, as the hook member  12  rotates counter-clockwise during high loading due to a tapered shape of the wedge portion  12   b , the blocking member  13  rotates clockwise so as to make contact with the hook member  12 . Specifically, the contact portion  13   a  of the block member  13  contacts the stopper portion  12   e  of the hook member  12 . A portion of the contact portion  13   a  that is close to the hook member  12  is formed in round chamfer shape  13   c  in order to create smooth contact therebetween and prevent unstable contact. 
       FIG. 4  shows the seat lock device  1  in a locked state in which the hook member  12  fully contacts the block member  13 . Due to a reactive force from the block member  13 , like working as a prop member, the hook member  12  can not rotate counter clockwise any more. In this way, the striker  4  is fully locked at the latched position, namely “locked state”. This means, despite high loading inputted to the vehicle body  7 , the seat lock device  1  can keep the seat back  3  in the upright position securely. In other words, the seat lock device  1  can prevent the seat back  3  from being folded unexpectedly even when there is a tool box or heavy stuff behind the seat, and serves as a secure seat lock device with fewer relatively fewer components. 
       FIG. 5  illustrates a device that is a symmetrical version of the seat lock device  1  described above. When a high loading happens at the vehicle body, the block member illustrated in  FIG. 5  rotates counter-clockwise so as to contact with the hook member. 
     The second embodiment will now be described with reference to  FIG. 6  through  FIG. 9 . In the second embodiment, a pivot pin  31  and a rotational pin  32  are explained in detail. These pins correspond to the pivot pin  13   b  and the rotational pin  12   c  in the first embodiments. In this second embodiment, a bracket  22  is attached to a vehicle body  21  but the bracket  22  can be attached to a side of seat back, in this invention scope. 
     In  FIG. 6 , the U-shaped bracket  22  has a plainer shape base plate  22   c  and leg portions  22   a  which are mounted to the vehicle body  21  at a distance of a length of the leg portions  22   a . By means of bolts  24  and flanges  22   b  of the bracket  22 , the base plate is fixed to the vehicle body  21  rigidly. The pins  31 , 32  are anchored at the base plate  22   c  with holding an upper link  25  which corresponds to the block member  13  and a lower link  26  which corresponds to the hook member  12 , and each pin 31 ,  32  is spaced apart from each other. On the surface of the vehicle body  21  corresponding to the locations where the two pins  31 ,  32  are positioned, receptacle holes  31   a ,  32   a  are formed. These receptacle holes  31   a ,  32   a  have a greater diameter bore than the diameter of the pins  31 ,  32  at predetermined clearance “d”, and the pins  31 ,  32  penetrate at L 1  and L 2  amount in longitudinal direction at penetration portions  31   b ,  32   b . In view of this concept, that the length of L 1 , L 2  is different or same is acceptable. 
       FIG. 7(   a ) is a plane view from the “B” direction in  FIG. 6 , and shows an ordinary state in use.  FIG. 7(   b ) is the same view in a high loading or dynamic load inputted state. In  FIG. 7(   a ), there are predetermined clearances between the pins  31 ,  32  and the receptacle holes  28 . In  FIG. 7(   b ), as mentioned above, due to dynamic load or severe acceleration change, the base plate  22   c  and the pins  31 ,  32  deform a distance of “d” until the pins  31 ,  32  contact with the receptacle holes  31   a , and  32   a . That is to say, the dynamic force transmitted from the vehicle body  21  to the pins  31 ,  32  is reduced by absorbing effect of these deformations. In this way, peak value of a dynamic force and shear force inputted to the pins  31 ,  32  is lowered with a fewer components structure. 
     In  FIG. 8 , the pins  31 ,  32  are fixed to the vehicle body  21  while the receptacle holes  31   c  and  32   c  are formed at the base plate  122 . This is another example of the second embodiment. 
     In  FIG. 9 , at the receptacle holes, emboss contact portions  31   d  and  122   d  are formed for purpose of strengthening of contact portion and a secure load transmission. 
     Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.