Abstract:
A first supporting member ( 10 ) supports a first seat member. A second supporting member ( 60 ) supports a second seat member rotatable relative to the first seat member. An angular restrictor ( 80, 90 ) is provided between the first and the second supporting members ( 10, 60 ) for restricting an angle between the first and the second supporting members ( 10, 60 ) within an angular range.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a seat reclining device in which a seat back rotates about a seat cushion, and, more specifically, to one adapted for a seat of a vehicle, such as an automobile.  
           [0003]    2. Description of Relevant Art  
           [0004]    Conventionally, this kind of a seat recliner has been known with the following constitution. The seat recliner includes: a frame mounted to the frame plate of a seat cushion; and a lid mounted to an arm plate of a seat back. The frame and the lid are rotatable relative to each other. The meshing of a locking gear, mounted on the frame, with an internal gear, formed on an inner peripheral face of the lid, prevents the frame and the lid from their relative rotation. When an operational shaft through the frame and the lid rotates, the locking gear operates via a cam plate. When the locking gear and the internal gear are disengaged from each other, the arm plate as the seat back is inclined forwardly due to the biasing force of a coil spring.  
         SUMMARY OF THE INVENTION  
         [0005]    In the aforementioned seat recliner, for example, the abutting of the arm plate against a flange provided to the frame plate allows the restriction of the operational angle of the seat back. This causes the arm plate and the frame plate to provided with stoppers, thus restricting the layout. The prevention of an extraneous substance between the arm plate and the flange of the frame plate needs the providing of a cover. This causes the increase of the number of components, thus enhancing a productive cost.  
           [0006]    It therefore is an object of the present invention to provide a seat reclining device for a vehicle in which a restrictor for the restricting of the operational angle of a seat back is housed in a locking mechanism.  
           [0007]    To achieve the objects, an aspect of the invention provides the following seat reclining device. A first supporting member supports a first seat member. A second supporting member supports a second seat member rotatable relative to the first seat member. An angular restrictor is provided between the first and the second supporting members for restricting an angle between the first and the second supporting members within an angular range.  
           [0008]    Preferably, the angular restrictor includes a cam mechanism.  
           [0009]    Preferably, the cam mechanism includes: a combination of a cam and a cam follower. A cam is integral with the first supporting member. A cam follower is integral with the second supporting member.  
           [0010]    Preferably, the cam mechanism includes a combination of cam and cam follower. A cam is integral with the second supporting member. A cam follower is integral with the first supporting member.  
           [0011]    Preferably, the cam has an opening formed to the first supporting member. The opening has a pair of end walls defining the angular range. The cam follower has a projection from the second supporting member. The projection is received in the opening for stopping the projection against one of the end walls.  
           [0012]    Preferably, the cam has an opening formed to the second supporting member. The opening has a pair of end walls defining the angular range. The cam follower has a projection from the first supporting member. The projection is received in the Ski opening for stopping the projection against one of the end walls.  
           [0013]    Preferably, the cam has an angular changer in the opening for changing the angular range.  
           [0014]    Preferably, the angular changer has a screwed member projecting from one of the end walls.  
           [0015]    Preferably, the seat reclining device further includes a switch for switching between locking and disengaging between the first and the second supporting members.  
           [0016]    Preferably, the switch includes a rotatable input member; a cam member rotatable the input member; and a locking member supported by the first supporting member. The locking member is movable between the second supporting member and the cam member. The locking member is followable with the cam member for locking with and disengaging from the second supporting member.  
           [0017]    Preferably, the first supporting member includes a pair of guides projecting therefrom. Guides have the locking member interposed therebetween to be guided between the second supporting member and the cam member.  
           [0018]    Preferably, the cam member includes a first cam plate rotatable with the input member for guiding the locking member to be locked with the second supporting member.  
           [0019]    Preferably, the cam member includes a second cam plate rotatable with the input member for guiding the locking member to be disengaged from the second supporting member.  
           [0020]    Preferably, the seat reclining device further includes a biasing member supported by the first supporting member. The biasing member biases against the cam member.  
           [0021]    According to the aspect of the invention, an arm plate and a frame plate improve in the degree of freedom of shape and layout. The omitting of a cover results in the reduction of the number of components and of a productive cost.  
           [0022]    The changer allows the operational angle between the first and the second seat members to be changed, thus corresponding with each specification of many kinds of vehicles.  
           [0023]    Achieved the restricting of the operational angle is the abutting of the projection against one of the end walls of the opening, thus allowing the considerably simple structure.  
           [0024]    The change of the amount of the projecting of the screwed member from an end wall allows the operational angle to be easily changed.  
       
    
    
     BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS  
       [0025]    The above and further objects and novel features of the present inven ion will more fully appear from the following detailed description when the same is read in conjunction with the accompany ng drawings, in which:  
         [0026]    [0026]FIG. 1A is an explanatory front view showing a partially broken lockin mechanism according to the first embodiment of the invention;  
         [0027]    [0027]FIG. 1B is a front view showing the operation of the locking mechanism of FIG. 1A;  
         [0028]    [0028]FIG. 2 is an exploded perspective view of the locking mechanism;  
         [0029]    [0029]FIG. 3 is an explanatory front view of a seat recliner for a vehicle.  
         [0030]    [0030]FIG. 4 is an explanatory view taken on line IV-IV of FIG. 3;  
         [0031]    [0031]FIG. 5 is an explanatory view taken on line V-V of FIG. 4;  
         [0032]    [0032]FIG. 6 is an explanatory front view of an arm plate;  
         [0033]    [0033]FIG. 7 is an explanatory sectional view taken on line VII-VII of FIG. 6;  
         [0034]    [0034]FIG. 8 is an explanatory front view showing the relationship between a cam and a cam follower of a locking mechanism according to the second embodiment of the invention;  
         [0035]    [0035]FIG. 9 is an explanatory front view showing the relationship among a cam, a cam follower, and a changer for movement range of a locking mechanism according to the third embodiment of the invention; and  
         [0036]    [0036]FIG. 10 is a perspective view of a seat into which the seat recliner is incorporated. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0037]    There will be detailed below the preferred embodiments of the present invention with reference to the accompanying drawings. FIGS. 1A to  7 , FIG. 8, or FIG. 9 shows the first embodiment, the second embodiment, or the third embodiment, respectively. Like members are designated by like reference characters. The embodiments show examples of three locking gears, while two or more than three ones are preferable.  
         [0038]    First Embodiment  
         [0039]    Seat recliner E 1  for a vehicle, as shown by the first embodiment, has lid  60  as a second supporting member, which covers the inner face of circular opening  14  formed to frame  10  as a first supporting member in a circular plate shape, and which rotates along the inner peripheral face of frame  10 . The meshing of locking gears  20  as a locking member normally located in frame  10  with internal gear  61  formed the inner peripheral face prevents frame  10  and lid  60  form relative rotation. The rotation of operation shaft  30  as a switch or an input member, passing through frame  10  and lid  60 , causes locking gears  20  to be centripetally drawn for the disengagement of the lock. This allows lid  60  to be rotated relative to frame  10 . These constitute locking mechanism  100 .  
         [0040]    Mounted on the outer peripheral face of frame  10  is frame plate  110  mounted to seat cushion  150 . Mounted on the outer side of lid  60  is arm plate  120  to seat back  160 .  
         [0041]    The outer peripheral face of lid  60  has a cam follower  80  located thereon. Cam follower  80  is movably mated with cam  90  as a cam located on the inner peripheral face of frame  10 . By the appropriate establishment of the angular range a of loose fitting means  90  for the rotation of the lid, the operational angle of lid  60  is restricted.  
         [0042]    The constitution of the above first embodiment is explained in detail.  
         [0043]    The locking mechanism  100  is constituted with circular plate shaped frame  10 . The mechanism has lid  60  with internal gear  61  on the inner peripheral face thereof, which covers the inner face of circular opening  14  formed to frame  10  and which is mounted frame  10  to rotate on its outer peripheral face along the inner peripheral face of frame  10 . The mechanism has locking gears  20  meshed with internal gear  61  of lid  60  radially slidably located on the inner face of frame  10 . The mechanism has rotatable operation shaft  30  passing through holes  12 ,  62  formed to the central portions of frame  10  and lid  60 , respectively. The mechanism has cam plate  40  as a first cam integral with operation shaft  30  to move locking gears  20  radially outward by the rotation of the operation shaft  30 . The mechanism has cam plate  50  as a second cam plate which is located on the inner face of cam plate  40  and which, due to the rotation of operation shaft  30 , rotates synchronously with cam plate  40  thus to move locking gears  20  radially inward. The mechanism has locking springs  70  biasing against cam plate  40  to normally press lock gears  20  radially outward. The biasing force of locking springs  70  causes locking gears  20  and internal gear  61  to be meshed with each other, thus preventing the rotation of lid  60  relative to frame  10 . The rotation of operation shaft  30  (as shown by the clockwise direction in FIG. 1) causes locking gears  20  to be centripetally drawn by cam plate  50  for the disengagement of the lock. This allows the rotation of lid  60  relative to frame  10 .  
         [0044]    In addition, as explaining locking mechanism  100  in detail, a plurality of locking gears  20  as three ones in the embodiment, are arranged on the inner face of frame  10  at an equal interval. The locking gears are radially slidably inserted between a pair of the parallel guide faces  11   b  of guides  11 , formed radially on the inner face of frame  10 .  
         [0045]    Locking gears  20  each have arced external locking gear  21  formed on the outer peripheral face thereof, with its radius identical to one of internal gear  61  of lid  60 . The inner peripheral faces  20   a  thereof each are in contact with the first cam face  41   a  of cam plate  40  to constitute engagement part  23 . The locking gears each have projection  22  provided on a side thereof and radially close to the inner periphery thereof, which engages with cam groove  51  of plate  50 . The locking gears each have projection  24  radially close to the outer periphery thereof. The locking gears each have opposite inner side faces  20   b  to slide on guide faces  11   b  of guides  11 . The locking gears each have outer side faces  20   c  which projects from side faces  20   b  and which abut against stopper faces  11   c.    
         [0046]    Operation shaft  30  is loosely fitted in through-holes  12 ,  62 , formed at the central portions of frame  10  and lid  60 , respectively. The shaft is loosely fitted and inserted in supporting holes  112 ,  122 , formed to frame plate  110  and arm plate, respectively. The portion of operation shaft  30 , projecting outwardly from frame plate  110  of operation shaft  30 , has operation lever  31  mounted thereto. The portion, projecting outwardly form arm plate  120 , has spline  32  for the connection of both locks, formed thereon. Operation lever  31  has operation knob  33  mounted thereto.  
         [0047]    Cam plate  40  is pressed in the intermediate portion of operation shaft  30  to be fixed thereto. The outer periphery thereof has cam face  41  formed thereon, which is engaged with engagement parts  23  each formed on the side of locking gear  20  in opposition to the external gear  21  for the outward pressing of locking gear  20 . Cam plate  40  has locking portions  43  locked with the outer ends of three locking springs  70  which have bases mounted to three projections  13  formed on the inner face of frame  10 , respectively. The locking portions are biased to normally press lock gears  20  outwardly.  
         [0048]    The cam plate  50  has mounting holes  52  for the fitting of mounting projections  42  therein which are provided on the side of cam plate  40  at the interval of  120  degree on the circumference of a circle about the axis of operation shaft  30 , thus being rotatable integrally with operation shaft  30 . The plate  50  defines cam grooves  51   a  loosely engaged with projections  22  in the locking of locking gears  20 . The plate defines cam grooves  51   b  radially inside of cam grooves  51   a.  The cam grooves  51   b  each guide the projection  22  to disengage locking gear  20  from internal gear  21 .  
         [0049]    Lid  60  is fitted in circular opening  14  formed on the inner face of frame  10 . Between the inner peripheral face of circular opening  14  and the outer peripheral face of lid  60 , the lid is rotatable relative to frame  10 . The inner peripheral face of  15  circular opening  14  formed to lid  60  has annular internal gear  61  formed thereon, which is meshable with external gears  21  of locking gears  20 . Locking gears  20  each have projection  24 , formed close to and radially outside of projection  22 . The abutting of projection  24  against the inner face of lid  60  causes locking gears  20  to be restrained not to move between lid  60  and frame  10 . Frame  10  and cover  60  are covered with ring-shaped cover K to hold their outer peripheries thereof, thus being rotatably supported relative to each other.  
         [0050]    Projection  80 , as stopper or a cam follower, projects from the outer periphery of lid  60 . Opening  90 , as a stopper loose fitting means or a cam, is formed in a fan shape for the loose fitting of projection  80  with the inner peripheral face of circular opening  14  of frame  10 . The opening is constituted with arced wall  91  about the axis of operation shaft  30 ; end walls  92 ,  93  connecting the both ends of arced wall  91  with the axis of operation shaft  30 .  
         [0051]    According to locking mechanism  100  with the aforementioned constitution, locking gears  20  are pressed outwardly by the cooperative function of locking springs  70  with cam plate  40 . External gears  21  are meshed with internal gears  61  of lid  60 , thus resulting in the lock of the rotation of lid  60 , as shown in FIG. 1A.  
         [0052]    In this lock state, when operation shaft  30  is rotated in the clockwise direction of FIG. 1, cam face  41  of cam plate  40  disengages from engagement portion  23  of locking gears  20 . The cooperation of cam grooves  51   b  with projections  22  of locking gears  20  causes the centripetal movement of locking gear  20 . The disengagement of external gears  21  of locking gears  20  from internal gear  61  of lid  60  causes the lid  60  to be disengaged, as shown in FIG. 1B. Thus, arm plate  120  rotates in a front direction (F 1 ) due to the biasing force of coil spring  130 .  
         [0053]    When projection  80  provided to lid  60  abuts against end wall  92  of opening  90  of frame  10 , the rotation of arm plate  120  as back seat  160  in a front direction (F 1 ) is restricted. By the appropriate establishment of the angular range a of opening  90  for the rotation of the lid, the operational angle of seat back  160  is appropriately set.  
         [0054]    Lid  60  and arm plate  120  are fixed, with a plurality of or three projections  63  in the embodiment formed on the outer face of lid  60  and mounting holes  123  formed to arm plate  120  to engage with projections  63 , being welded each other. Frame  10  and frame plate  110  are fixed, using the similar manner.  
         [0055]    Arm plate  120  has mounting portion  121  to the seat back; and holder  140  for holding inner portion  131  of coil spring  130 .  
         [0056]    Holder  140  is provided under through-hole  122  of arm plate  120 . Along the locus of the radius of a predetermined curvature about hole  122 , arm plate  120  is cut and raised in a semicircle shape. Opening  142  formed to the end of cut and raised part  141  has inner end  132  of coil spring  130  latched thereon. Outer end  133  of coil spring  130  is latched on locking pin  111  fixed to frame plate  110 .  
         [0057]    According to the aforementioned seat recliner for a vehicle, the restriction of the operational angular range of arm plate  120  as seat back  160  is performed by the cooperative function of projection  80  as a cam follower, formed to lid  60  housed in locking mechanism  100 , with opening  90  as a cam provided to frame  10 .  
         [0058]    The means for the restriction of the operational angular range of seat back  160  is included in locking mechanism  100 , and the shapes and layout of arm plate  120  and frame plate  110  improve in the degree of freedom. When seat back  160  is adjusted at an operational angle, the situation that an extraneous substance is interposed between arm plate  120  and frame plate  110  is perfectly removed, thus allowing a cover to be omitted. This causes the reduction of the number of components, thus reducing the productive cost.  
         [0059]    Next, the second embodiment of the invention is explained, referring to FIG. 8. Attached to the elements in common with the elements of the first embodiment are the same characters, to omit their explanations.  
         [0060]    In the second embodiment, projection  80  as a cam follower formed on the inner peripheral face of circular opening  14  of frame  10 . Opening  90  as a cam is formed on the outer peripheral face of lid  60 .  
         [0061]    Another constitution is similar to one of the first embodiment. The second embodiment has the similar function and benefit to the first embodiment.  
         [0062]    Next, the third embodiment of the invention is explained, referring to FIG. 9. Attached to the elements in common with the elements of the first and second embodiments are the same characters, to omit their explanations.  
         [0063]    In the third embodiment, located in opening  90  as a cam is screw  94  as a changer for angular range, which allows the range of the movement of projection  80  as a cam to be changed.  
         [0064]    This screw  94 , in the embodiment, is screwed into end wall  92  of opening  90  for the axial movement. The change of the amount of the projecting screw  94  allows the operation angular range of seat back  160  to be changed.  
         [0065]    The entire contents of Japanese Patent Applications P2000-301174 (all filed Sep. 29, 2000) are incorporated herein by reference.  
         [0066]    While preferred embodiments of the present invention have been described using specific terms, such description is for illustrative purposes, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.