Abstract:
A seat device adapted to be fixed to engagement members on a vehicle floor includes a first engagement member supporting a front portion of the seat device, a second engagement member supporting a rear portion of the seat, a first lock engagable with the first engagement member, a second lock engagable with the second engagement member. The first lock is supported on the seat device and includes a bracket rotatably supported relative to the seat device and being engagable with the first engagement member and a hook member supported on the bracket and being able to maintain an engagement of the bracket with the first engagement member. A contact portion is provided on the hook member for contacting on a portion of the seat device to prevent a release operation of the hook member when the bracket is out of a predetermined position range relative to the seat device.

Description:
This application is based on and claims priority under 35 U.S.C. § 119 with respect to Japanese Application No. 2002-219864 and No. 2002-219865, both of these applications were filed on Jul. 29, 2002, the entire content is incorporated herein by reference. 
   TITLE OF INVENTION 
   Seat apparatus for a vehicle 
   FIELD OF THE INVENTION 
   This invention generally relates to a seat apparatus for a vehicle. More particularly, the seat apparatus pertains to a vehicle seat which can be folded, tumbled or removed for multipurpose use of the vehicle room space such as by expanding for loading cargo. 
   BACKGROUND OF THE INVENTION 
   A vehicle seat for multipurpose use, for a example disclosed in U.S. patent application Ser. No. 5,498,051, usually is provided with a first lock unit provided with a rotational axis and supported on the vehicle floor at the front end portion of the seat device. Also, the seat has a second lock unit at the rear end portion of the seat device. The first and second lock unit are arranged to be able to engage with or release from a first and a second strikers fixed on the vehicle floor. 
   The second lock unit is released from the second striker, then the seat can be rotated around the rotational axis of the first lock unit and made to stand up as its front portion to be lower, that is, as the seat to be in tumbled condition. Further, by operating a hook installed on the first lock unit to release the engagement from the first striker, the seat can be removed from the floor. Thus, the cargo space on the floor can be expanded. 
   Usually, in the seat, as above mentioned, which can be arranged to be in tumbled condition, the hook of the first lock unit is possible to be released even when the seat is not in tumbled condition. For example, even when the seat is in sitting use condition of the occupant, the first lock unit may be released. It is difficult to restore the seat to be in sitting use condition again, because the seat may take several postures. 
   Also, the distance between the first and second lock units and the first and second strikers varies depending on manufacturing or assembling tolerance. This generates difficulty of locking operation or over load on the lock units when the seat is restored to be in the sitting use condition from the tumbled condition. 
   SUMMARY OF INVENTION 
   According to a first aspect of the present invention, the seat device  1  can be released from the vehicle floor only when the seat is in tumbled condition, that is, the seat device is rotated around an axis to be in almost upright position on the floor, and fail safe for the seat arrangement operation is obtained. 
   According to a second aspect of the present invention, a long hole is provided on a first bracket of a first lock unit which supports a seat. The rotation axis is arranged to be movable in the long hole, and on the restoring process of the seat from the tumbled condition to normal sitting use condition, by a cam hole and a pin which are provided on the first and second bracket, the seat is shifted along the long hole to a predetermined position for making the second lock unit can engage. 

   
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     The foregoing and additional features and characteristics of the present invention will become more apparent from the following detailed description considered with reference to the accompanying drawing figures in which like reference numerals designate like elements. 
       FIG. 1  is a side view of a seat device in folded condition according to an embodiment of the present invention. 
       FIG. 2  is an exploded perspective view the first locking mechanism of the seat device. 
       FIG. 3  is a side view of the first locking mechanism when the seat is in the tumbled condition. 
       FIG. 4  is a side view of the first locking mechanism when the seat is restored from the tumbled condition to the folded condition. 
       FIG. 5  is a side view of the first locking mechanism when the seat is in the folded condition. 
       FIG. 6  is a side view of the second locking mechanism when the seat is in the folded condition. 
       FIG. 7  is a side view of a cam hole profile formed on the first locking mechanism. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   A seat device  1  for a vehicle includes a seat  10 , a first lock  2  which supports a front portion of the seat  10  on a vehicle floor  9  and a second lock  4  which supports a rear portion of the seat device  1  on a vehicle floor  9 . A sitting use condition of the seat  10  is shown by two dots line A, and a folded condition is shown by solid line in FIG.  1 . 
   The seat  10  is provided with a seat cushion  11  and a seat back  12 , a seat reclining adjuster (not shown) which is disposed between the seat cushion  11  and the seat back  12 . The seat reclining adjuster works to adjust the seat back  12  angle position in the sitting condition and also to the folded condition. The back side of the seat back  12  is available for use as a table in the vehicle space, when the seat back  12  is folded over the seat cushion  11 . 
   As further shown by two dots line B in  FIG. 1 , the seat  10  can be turned forward (counter clockwise direction in  FIG. 1 ) by releasing the second lock  4  from the floor  9 . Then the seat cushion  11  stands up to almost upright position as its front end to be lower, that is, to be in tumbled condition. Then, the seat  10  can be removed from the floor  9  by operating the first lock  2  and releasing the first lock  2 . 
   As shown FIG.  1  and  FIG. 2 , the first lock  2  includes a first lock unit  20  displaced on the seat  10  and a first striker  30  (a first engaging member). The first striker  30  has a base  33  fixed on the floor  9  via holes  33   a ,  33   b  and two engagement rods  31 ,  32 . The first lock unit  20  has a lower bracket  28 , and the lower bracket  28  has two grooves  28   a ,  28   b  engaging with horizontal engagement portions  31   a ,  32   a  formed on the engagement rods  31 ,  32 . The groove  28   a  engaging with the front horizontal engagement portion  31   a  has a mouth opening downward, and the groove  28   b  engaging with the rear horizontal engagement portion  32   a  has a mouth opening rearward. 
   As shown in  FIG. 2 , the first lock unit  20  includes an upper bracket  21  rotatably connected by a rotational axis  22  on the lower bracket  28 . The upper bracket  21  is fixed on a front and under surface portion of a frame  11   a  of the seat cushion  11  via fixing holes  21   c . A fixing nut  29  is fixed in a hole  28   d  on an upper end portion of the lower bracket  28  at a boss portion  29   b , and the rotational axis  22  of the upper bracket  21  is fixed on a screw portion  29   a  of the fixing nuts  29 . Along hole  21   b  is formed on the upper bracket  21 , the rotational axis  22  penetrates through the long hole  21   b . The long hole  21   b  extends rearward when the seat cushion  11  is supported by both the first and second locks  2 ,  4 . The width of the long hole  21   b  is almost equal with the diameter of a boss portion  22   a  of the rotational axis  22 . A cam hole  21   a  with curved profile is formed on the opposite side of the fixing hole  21   c  relative to the long hole  21   b . A pin  23  is fixed in a hole  28   f  on the side surface of the lower bracket  28 , and the pin  23  is inserted in the cam hole  21   a . The each end of the cam hole  21   a  and the pin  23  contact each other, when the lower bracket  28  rotates relative to the upper bracket  21 , then the relative rotation range of the lower bracket  28  and the upper bracket  21  is defined. 
   As shown in  FIG. 2 , on the side surface of the lower bracket  28 , a hook  25  is rotatably supported in a hole  28   c  by a pin  27  which is fixed in a hole  25   b  on the hook  25 . The hole  28   c  on the lower bracket  28  is displaced at the location under the pin  23  and over the groove  28   a . At the lower part of the hook  25 , a groove  25   a  opening forward is formed, and the groove  25   a  can maintain the engagement rod  31  in the groove  28   a  by an engagement of the groove  25   a  with the horizontal engagement portion  31   a  of the engagement rod  31 . 
   A slit  27   b  is formed on the pin  27 , and one end of a coil spring  65  is hooked in the slit  27   b  and the other end of the coil spring  65  is hooked in a hole  28   e  formed on the lower bracket  28 . The coil spring  65  applies rotational force to the hook  25  to engage the hook  25  with the engagement rod  31 . On an outer surface of the pin  27 , plural grooves  27   a  are formed. For fixing an operation lever  64  with the pin  27 , a hole  64   a  with plural grooves is formed on the operation lever  64 . The other end portion of the operation lever  64  is fixed with the pin  27  of the first lock unit  20  installed on the other side of the seat  10 . When the operation lever  64  is pulled upwardly against the force of the coil spring  65 , the hook  25  is released from the engagement rod  31 . 
   As shown in  FIG. 3  to  FIG. 5 , a projected portion  25   c  is formed on the hook  25 . As shown in  FIG. 3  by two dots line C, the projected portion  25   c  is rotable on counter clockwise direction, when the seat  10  is in the tumbled condition. However, the seat is not in the tumbled condition, the projection  25   c  is prevented from rotation by a lower edge of the upper bracket  21 . This means that the first lock unit  20  is not released when the seat  10  is not in the tumbled condition. 
   On the fixing nut  29 , a pipe  61  extending horizontally in the wide direction of the seat  10  is installed for connecting the first lock units  20  on the both side of the seat  10 . On the outer surface of the pipe  61 , a chock  63  is welded, an one end  62   a  of a tumble spring  62  formed in a shape of coil is hooked on a pin  26  fixed in a hole  21   d  on the upper bracket  21 , and the other end  62   b  of the tumble spring  62  is hooked on the chock  63 . The tumble spring  62  applies rotational force to the seat  10  forward so as to make the seat  10  be in the tumbled condition, that is, to counter clockwise direction in FIG.  1 . The tumble spring  62  helps tumble or restoring operation of the seat  10  by balancing the weight of the seat  10 . 
   As shown in FIG.  1  and  FIG. 6 , the second lock  4  includes second lock unit  40  which is installed on the rear lower portion of the frame  11   a  of the seat  10 , and a second striker  50  which is fixed on the floor  9 . The second striker  50  has a similar structure with the first striker  30 , and has an engagement rod  51  with a horizontal engagement portion  51   a.    
   The second lock unit  40  has a known mechanism as being applied for a vehicle door lock, and includes a latch  43  and pawl  44  engaging with the latch  43 . The latch  43  engages with the second striker  50 , and the engagement is maintained when the rotation of the latch  43  is stopped by the pawl  44 . The engagement of the latch  43  is released from the second striker  50  by the pull operation of a cable  45  connected on the pawl  44 . The cable  45  may be arranged so as to be pulled in cooperation with the folding of the seat back  12 . When the second lock unit  40  is released, the seat  10  can be rotated forwardly around the rotational axis  22 , and be brought in the tumbled condition. 
   As shown in  FIG. 6 , the bracket  42  included in the second lock unit  40  has a groove  41  opening downward. The lower portion of the groove  41  has wider width for easily acceptance of the horizontal engagement portion  51   a  of the engagement rod  51 , even when the position of the horizontal engagement portion  51   a  or the seat  10  shifts forward or rearward by a reason of manufacturing or assembling tolerance, as shown by two dots line in FIG.  6 . 
   The operation of the seat device  1  is explained herein after. 
   The each situation of the first lock  2  is shown in  FIG. 3 , FIG.  4  and  FIG. 5 , when the seat  10  is moved from the folded condition to the tumbled condition, or the restoring movement from the tumbled condition to the folded condition. Further, as shown in detail in  FIG. 7 , an upper inner edge of the cam hole  21   a  is formed with curbed profile, and when a radius of “r” is set as constant, a center of the radius “r” moves along the center line of the long hole  21   b . Therefore, as shown in  FIG. 7 , the seat  10  is in the tumbled condition, the rotational axis  22  is in the upper most position of the long hole of the long hole  21   b , then according to the restoring movement of the seat  10  from the tumbled condition to the folded condition (from the condition shown in  FIG. 4  to the condition in FIG.  5 ), the rotational axis  22  gradually moves downward in FIG.  7 . When the seat  10  is restored in the folded condition, the rotational axis  22   a  is positioned in the center of the long hole  21   b  in the length direction of the long hole  21   b . In the case that the position of the second striker  50  deviates from the designed position fore or aft due to the tolerance of manufacturing or assembling, the seat  10  is movable with the range defined by the long hole  21   b  in either direction. Therefore the horizontal engagement portion  51   a  of the second striker  50  is smoothly conducted into the groove  41  and the second lock  4  achieves lock engagement. 
   As shown by two dots line in  FIG. 1 , the tumbled condition of the seat  10  is maintained by the tumble spring  62 , also the seat  10  can be fastened by a seat belt or other fastening means for maintaining the tumbled condition, then an expanded floor space is available for much cargo. 
   As shown in FIG.  4  and  FIG. 5 , when the seat  10  is not in the tumbled condition, the hook  25  is prevented from being released, because the projection  25   c  formed on the hook  25  hits on the upper bracket  21 . Only when the seat  10  is in the tumbled condition, the operation lever  64  can be turned against the coil spring  65  to release the hook  25  from the engagement rod  31 .