Patent Publication Number: US-10329810-B2

Title: Check link apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from Japanese Patent Application No. 2012-178427 filed on Aug. 10, 2012, the entire subject-matter of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a check link apparatus which defines a full open position of a door of a vehicle. 
     2. Description of the Related Art 
     A check link apparatus is used in a vehicle such as an automotive vehicle. This check link apparatus is disposed between a vehicle main body and a door and is configured to define a full open position (a maximum open position) of the door. 
     A general check link apparatus includes an arm, which is connected to a vehicle main body rotatably at one end thereof, and a holding member, which is mounted on a door and through which the arm is inserted slidably, and is configured to define a full open position of the door by bringing a stopper portion, which is provided at the other end of the arm, into abutment with an abutment surface of the holding member. Because of this, the stopper portion, which receives a load when the door is fully opened, is required to be strong. 
     For example, Japanese Patent No. 3099226 discloses a check link having a stopper portion, in which strength thereof is increased by forming a projecting portion by bending an expanded portion formed at an end portion of a metal core of an arm and by covering this projecting portion with a resin material. 
     In the case of the check link apparatus disclosed in Japanese Patent No. 3099226, since the check link apparatus includes the stopper portion having the projecting portion formed by bending the metal core, the strength of the metal core itself at the stopper portion is increased. However, the projecting portion and a corner portion of a plate end face of the metal core which forms the projecting portion are disposed ahead of a case of a holding member which travels along the arm to be brought into abutment therewith via the resin material. Because of this, when impact is applied to the resin material, which covers the stopper portion, as a result of the holding member coming into abutment with the stopper portion, there may be a situation in which the resin material is separated from the stopper portion, starting from the projecting portion of the metal core or the corner portion thereof. With a view to preventing the separation of the resin material from the stopper portion, a vertical dimension of the stopper portion needs to be increased so as not only to increase its load receiving area but also to decrease an angle difference when a vertical offset abutment occurs between the case and the stopper portion. This eventually enlarges the stopper portion. Moreover, in this check link apparatus, since the projecting portion is formed by bending the expanded portion formed by cutting a sheet material, there is also caused a problem that the workability is deteriorated, leading to high production costs. 
     SUMMARY 
     Illustrative aspects of the invention provide a check link apparatus which enables to configure a highly strong stopper portion at low costs. 
     According to one illustrative aspect of the invention, there is provided a check link apparatus comprising: an arm comprising a metal core that comprises: a plate-shaped arm core portion; a connecting core portion that is provided at a first end of the arm core portion and is connected rotatably to either of a vehicle main body or a door; and a stopper core portion that is provided at a second end, which is opposite to the first end, of the arm core portion and expands in a direction intersecting a longitudinal direction of the arm core portion, wherein a stopper portion is formed by covering at least the stopper core portion with a resin material; and a holding member that is mounted on the other of the vehicle main body and the door, through which the arm core portion is slidably inserted, wherein the holding member is configured to define a full open position of the door by being brought into abutment with the stopper portion, wherein the stopper core portion has a curved surface on an end face that is configured to face an abutment surface of the holding member at least when the abutment surface of the holding member is brought into abutment with the stopper portion. 
     According to the configuration described above, by providing the curved surface on the end face of the stopper core portion covered with the resin material which lies on the side with which the holding member is brought into abutment, when the load generated in association with the abutment between the holding member and the stopper portion is applied between the resin material and the curvilinear curved surface provided on the end face, the load can be dispersed by the curved surface, thereby making it possible to avoid a risk that the load is concentrically to a single point such as a corner portion. Therefore, a concentric application of the load to a specific location on the resin material can be prevented which would otherwise generate the separation of the resin material therefrom. Thus, the separation of the resin material from the stopper core portion can be prevented, thereby making it possible to form the highly strong stopper portion. Further, since the stopper portion is made up of the stopper core portion that is provided by expanding the other end of the arm core portion in the width direction, the stopper portion can be formed only by cutting, for example, a single sheet of steel into a metal core having a desired external shape, so that the workability becomes superior and the production costs can also be reduced. Moreover, the side of the stopper core portion which faces the holding member is formed by the curved surface made up of the thickness-direction face of the sheet of steel (e.g., the end face of the sheet of steel), and therefore, the strength of the stopper core portion is increased. This suppresses the deformation of the stopper core portion when the holding member is brought into abutment therewith, thereby making it possible to enhance the durability thereof. In this way, the stopper portion is configured such that the deformation of the stopper core portion is suppressed and that the load applied from the holding member is received by the curved surface, whereby the separation of the resin material can be prevented in a more ensured fashion. 
     According to another illustrative aspect of the invention, an extension extending along a direction in which a load is applied to the stopper core portion by the holding member is positioned where the extension passes the curved surface of the stopper core portion at least when the abutment surface of the holding member is brought into abutment with the stopper portion. 
     According thereto, when the abutment surface of the holding member is brought into abutment with the stopper portion, the load applied to the stopper portion can be dispersed by the curved surface of the stopper core portion in a more ensured fashion. 
     According to still another illustrative aspect of the invention, a hole portion is formed in the stopper core portion so as to penetrate the stopper core portion in a thickness direction thereof for receiving the resin material to be filled therein. The hole portion may be formed substantially in a center of the stopper core portion. 
     According thereto, at the stopper portion, the load from the holding member can be received not only by the curved surface but also by an inner circumferential surface of the hole portion, that is, the load receiving area of the stopper portion can be expanded by the hole portion. Moreover, the hole portion may be positioned substantially in the center of the stopper core portion. Consequently, the load applied to the resin material from the holding member can be further dispersed in a balanced manner. Furthermore, the coverings of the resin material formed on the upper and lower surfaces of the stopper core portion are connected to each other by the hole portion, so that the separation of the resin material can be suppressed in a more ensured fashion. 
     According to still another illustrative aspect of the invention, the arm portion is formed by the arm core portion being covered with the resin material, and at least one set of a recessed portion and a protuberant portion, on which a slider of the holding member is configured to slide, is formed by the covered resin material, and the stopper portion and the abutment surface of the holding member are brought into abutment with each other when the slider of the holding member is positioned on an upwardly inclined surface, which slopes up from the recessed portion to the protuberant portion, or on the protuberant portion. 
     According thereto, the holding member receives a force acting thereon in an opposite direction to the moving direction thereof by means of the sliding contact action between the slider and the upwardly inclined surface, whereby the load transmitted from the holding member to the stopper portion is suppressed. Therefore, the damage to the stopper portion and the generation of impact noise can be reduced, and it makes possible to prevent the separation of the resin material configuring the covering in a more ensured fashion. 
     According to still another illustrative aspect of the invention, a thickness of the resin material that covers the stopper core portion is made to become the thickest at a side of the stopper core portion configured to face the holding member. 
     According thereto, while avoiding the enlargement of the stopper portion, the thick resin material is allowed to be deformed to thereby act as a cushion to receive the load from the holding member when the stopper portion receives the load from the holding member. Thus, the separation of the resin material can be suppressed in a more ensured fashion. 
     According to still another illustrative aspect of the invention, the resin material that covers the stopper core portion has a first thickness lying between the end face of the stopper core portion which is configured to face the abutment surface and the side configured to face the holding member, the resin material that covers the stopper core portion has a second thickness lying between the curved surface and the side configured to face the holding member, and the second thickness is larger than the first thickness. 
     According to still another illustrative aspect of the invention, the resin material that covers the stopper core portion has a third thickness at portions other than the end face and the curved surface of the stopper core portion, and the first thickness is larger than the third thickness. 
     According to the invention, by providing the curved surface on the end face of the stopper core portion, which is covered with the resin material, on the side with which the holding member is brought into abutment, when the load generated in association with the abutment between the holding member and the stopper portion is applied between the resin material and the curvilinear curved surface provided on the end face, the load can be dispersed by the curved surface, thereby making it possible to suppress a situation where the load is concentrically to a single point such as a corner portion. Therefore, it is possible to avoid the concentric application of the load to the specific location on the resin material which would otherwise generate the separation of the resin material therefrom. Thus, the separation of the resin material from the stopper core portion can be prevented, thereby making it possible to form the highly strong stopper portion. Further, the stopper portion is made up of the stopper core portion that is provided by expanding the other end of the arm core portion in the width direction. For example, the stopper portion can be formed only by cutting the single sheet of steel into the metal core having the desired external shape. Therefore, according to the invention, the workability becomes superior and the production costs can also be reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a check link apparatus according to an embodiment of the invention; 
         FIG. 2  is a sectional view taken along the line II-II in  FIG. 1 ; 
         FIG. 3  shows schematic plan views of a main part of a four-wheel vehicle which installs the check link apparatus, in which  FIG. 3A  is a plan view showing a state in which a door is closed, and  FIG. 3B  is a plan view showing a state in which the door is opened; 
         FIG. 4  is a plan view of an arm of the check link apparatus; 
         FIG. 5  is a side view of the arm shown in  FIG. 4 ; 
         FIG. 6  is a plan view of a metal core which configures the arm; 
         FIG. 7  shows enlarged plan views of a stopper portion and a peripheral portion thereof of the arm, in which  FIG. 7A  is a plan view showing a state in which a holding member comes into straight abutment with the stopper portion, and  FIG. 7B  is a plan view showing a state in which the holding member comes into offset abutment with the stopper portion; 
         FIG. 8  is a side sectional view showing a state in which the door is in a full open position and the holding member is brought into abutment with the stopper portion; and 
         FIG. 9  is a plan view showing positions of the holding member in relation to the arm in the check link apparatus when the door is opened or closed. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a check link apparatus according to the invention will be described in detail based on a preferred embodiment by reference to the accompanying drawings. 
       FIG. 1  is a plan view of a check link apparatus  1  according to an embodiment of the invention.  FIG. 2  is a side sectional view of the check link apparatus  1  shown in  FIG. 1  which is taken along the line II-II therein.  FIG. 3  shows schematic plan views of a main part of a four-wheel vehicle which installs the check link apparatus  1 , in which  FIG. 3A  is a plan view showing a state in which a door D is closed, and  FIG. 3B  is a plan view showing a state in which the door D is opened. 
     As shown in  FIGS. 1 to 3 , the check link apparatus  1  includes a holding member  10  and an arm  20 . The check link apparatus  1  is disposed between a vehicle main body (a vehicle body) B and a door D. In this embodiment, as the door D to which the check link apparatus  1  is applied, a front right-hand side door of the vehicle main body B is illustrated. The door D is rotatably supported on a door hinge Hj of the vehicle main body B at a front end portion thereof and is configured to be rotated about the door hinge Hj so as to be opened or closed between the closed state shown in  FIG. 3A  and the opened state shown in  FIG. 3B . 
     As shown in  FIGS. 1 and 2 , the holding member  10  is fitted on the arm  20  so as to slide on the arm  20  along a longitudinal direction thereof (also, refer to  FIG. 8 ) and is configured to define a full open position (a maximum open position) of the door D (refer to  FIG. 3B ) by being brought into abutment with a stopper portion  20   c , which will be described later, provided at one end of the arm  20 . 
     In the case of this embodiment, the holding member  10  has a case  11  and a cover plate  12  and holds a check mechanism  14  within a space defined by the case  11  and the cover plate  12 . The case  11  and the cover plate  12  are made of a sheet of steel, for example. The cover plate  12  is locked and fixed to the case  11  by locking claws  11   b  which are formed on the case  11 . The holding member  10  is fixed to a door panel DP by the case  11  being fixed to the door panel DP by two bolts  13  and nuts, not shown. 
     An opening  10   a  in the holding member  10 , through which the arm  20  is inserted, is defined by openings  11   a ,  12   a  which are formed in centers of the case  11  and the cover plate  12 , respectively. Incidentally, the case member  10  may have any other configurations than the above-described configuration which uses the case  11  and the cover plate  12  and may be formed into, for example, an integral box-like shape. 
     The check mechanism  14  has a pair of sliders  15 ,  15  configured to abut upper and lower surfaces of the arm  20  and a pair of coil springs  16 ,  16  configured to bias the corresponding sliders  15  towards the arm  20 . The sliders  15  are formed of a synthetic resin having a small frictional coefficient relative to a covering  22  of the arm  20  such as polyacetal, for example. Incidentally, an elastic element such as a rubber may be used in place of the coil spring  16 . 
       FIG. 4  is a plan view of the arm  20  of the check link apparatus  1 ,  FIG. 5  is a side view of the arm  20  shown in  FIG. 4 , and  FIG. 6  is a plan view of a metal core  21  which configures the arm  20 . Additionally,  FIG. 7  shows enlarged plan views of the stopper portion  20   c  and a peripheral portion thereof of the arm  20 , in which  FIG. 7A  is a plan view showing a state in which the holding member  10  comes into straight abutment with the stopper portion  20   c , and  FIG. 7B  is a plan view showing a state in which the holding member  10  comes into offset abutment with the stopper portion  20   c.    
     As shown in  FIGS. 1, 2 and 4 to 7 , the arm  20  is configured by the plate-shaped metal core  21  and the covering  22  that is of a synthetic resin and covers the metal core  21 , and the arm  20  is a plate-shaped member extending along the longitudinal direction while being curved slightly in a planer view. The arm  20  includes an arm portion  20   a  that is long and has a plate-like shape, a connecting portion  20   b  that is formed at one end of the arm portion  20   a  and the stopper portion  20   c  that is formed at the other end of the arm portion  20   a . It is preferable to use a synthetic resin which is easy to be worked and strong as a material for the covering  22 , and it is hence preferable to use a thermoplastic resin such as polypropylene, nylon, ABS resin or polyacetal. Incidentally, in  FIG. 7 , in order to clarify the shape of the metal core  21 , the covering  22  is indicated by a chain double-dashed line. 
     As shown in  FIGS. 2 and 4 , the connecting portion  20   b  has an opening portion  20   e  formed in the center portion thereof in such a way that an opening portion  21   e , which will be described later, is covered with the covering  22 . As shown in  FIGS. 1, 2 and 7 , a surface of the stopper portion  20   c  facing the arm portion  20   a  is made into a flat receiving surface Fa with which the holding member  10 , that is, an abutment surface  12   b  of an outer surface of the cover plate  12  is brought into abutment. 
     As shown in  FIGS. 1 and 2 , in the arm  20 , the connecting portion  20   b  provided at the one end of the arm portion  20   a  is connected to a bracket Bk, which is fixed to the vehicle main body B, with a swing pin or pivot P. And, the stopper portion  20   c  provided at the other end of the arm portion  20   a  is inserted through an arm insertion hole Ha formed in the door panel DP to be disposed within the door D via the holding member  10 . The bracket Bk is fixed to the vehicle main body B with a bolt  23  while being positioned and prevented from rotation by a projecting portion Bkp. 
     As shown in  FIGS. 2 and 5 , in the arm  20 , the covering  22  is molded over the metal core  21  so as to cover it such that the thickness of the synthetic resin configuring the covering  22  changes along the longitudinal direction. Although the thickness of the covering  22  is constant at an end portion of the arm portion  20   a  which lies to face the connecting portion  20   b , the thickness increases towards a longitudinal center of the arm portion  20   a  and then decreases at a longitudinal intermediate portion (a first check portion Pc 1 ). Thereafter, the thickness increases again to become constant and decreases again near the stopper portion  20   c  (a second check portion Pc 2 ), increasing thereafter again. By changing the thickness of the covering  22  in this way, a first protuberant portion  22   a , a first recessed portion  22   b  (the first check portion Pc 1 ), a second protuberant portion  22   c , a second recessed portion (the second check portion Pc 2 ) and a third protuberant portion  22   e  are formed on the covering  22  from a substantially central portion continuously and sequentially in that order in a direction from the connecting portion  20   b  end towards the stopper portion  20   c  end. 
     As shown in  FIGS. 2 and 4 to 6 , the metal core  21  configuring the arm  20  is made up of a single plate. This single plate is formed substantially into a T shape and has an arm core portion  21   a  that is made of a sheet of steel and extends along the longitudinal direction while being curved slightly, a connecting core portion  21   b  that is formed at one end of the arm core portion  21   a , and a stopper core portion  21   c  that is formed at the other end of the arm core portion  21   a  and expands in a width direction of the arm core portion  21   a.    
     Resin holes  21   d  are formed in appropriate locations on the arm core portion  21   a . The resin configuring the covering  22  enters the resin holes  21   d , whereby the arm core portion  21   a  and the covering  22  are made difficult to be separated from each other. The opening portion  21   e  is formed in the connecting core portion  21   b  in a position which corresponds to the connecting hole  20   e  formed in the arm  20  at the one end thereof, and a diameter of the opening portion  21   e  is larger than (e.g., slightly larger than) a diameter of the connecting hole  20   e.    
     Here, the configuration of the stopper portion  20   c  will be described more specifically by reference to  FIGS. 4 to 8 . 
     The stopper portion  20   c  is formed by covering the stopper core portion  21   c  of the core metal  21  with the covering  22 , and the covering  22  is molded there into a tapered rectangular shape. An end face of the tapered rectangular covering  22  which lies on a side facing the arm portion  20   a  configures the receiving surface Fa against the holding member  10 . 
     As shown in  FIGS. 6, 7A and 7B , the stopper core portion  21   c  extends from the arm core portion  21   a  towards one end of the core metal  21  and has a pair of widthwise widened portions  24 ,  24  which are expanded in a direction (a width direction) intersecting the longitudinal direction of the arm core portion  21   a . The stopper core portion  21   c  is formed into a trapezoidal shape which tapers towards one end thereof in a planar view. The stopper core portion  21   c  has substantially the same thickness as that of the arm core portion  21   a  (refer to  FIGS. 2 and 5 ). End faces Fb, Fb, which are thickness surfaces defined by a thickness of the stopper core portion  21   c  of the core metal  21  (end faces of the sheet metal) corresponding to the receiving surface Fa of the covering  22 , are provided at the widthwise widened portions  24 ,  24 . Curved surfaces Fc, Fc are provided between the end faces Fb, Fb and external side portions (e.g, external side portions of the stopper core portion  21   c  where the widthwise widened portions  24 ,  24  have a maximum width). The curved surfaces Fc are curved so as to escape from an arm core portion  21   a  side towards a stopper core portion  21   c  side. Also, the curved surfaces Fc are provided on the end faces Fb which face the abutment surface  12   b  of the holding member  10  at least when the abutment surface  12   b  is brought into abutment with the stopper portion  20   c . Therefore, the load from the holding member  10  is dispersed at the curved surfaces Fc. 
     As shown in  FIG. 7A , extensions L are positioned such that each of which extends from a respective edge portion of the opening  10   a  (the opening  12   a ) of the holding member  10  in a direction in which the load is applied to the stopper core portion  21   c  from the holding member  10  and passes the curved surfaces Fc of the stopper core portion  21   c  in a state where the door D is fully opened and the holding member  10  is brought into abutment with the stopper portion  20   c.    
     As shown in  FIG. 7B , even in a state where the door D is fully opened and the holding member  10  is brought into offset abutment with the stopper portion  20   c , the extension L is positioned so as to extend from the edge portion of the opening  10   a  (the opening  12   a ) of the holding member  10  in the direction in which the load is applied to the stopper core portion  21   c  from the holding member  10  and pass the curved surface Fc of the stopper core portion  21   c . The offset abutment means a phenomenon in which the abutment surface  12   b  of the holding member  10  is brought into abutment with the receiving surface Fa of the stopper portion  20   c  in such a state that the abutment surface  12   b  and the receiving surface Fa are out of parallel due to deterioration with age of the check link apparatus as a result of frequent usage thereof. 
     A circular hole (a hole portion)  26  is formed substantially in the center of the stopper core portion  21   c  so as to penetrate the stopper core portion  21   c  in a thickness direction. The circular hole  26  is included in a widthwise dimension of the arm core portion  21   a  in a longitudinal direction of the arm core portion  21   a  and is formed in a position which lies between a distal end face  25  of the stopper core portion  21   c  and roots of the widthwise widened portions  24 . In the circular hole  26  formed in this way, projections such as burrs are not left on upper and lower circumferential edge portions which configure boundaries with upper and lower surfaces of the stopper core portion  21   c , and the circumferential edge portions are made to be flush with or are depressed slightly further downwards than the upper and lower surfaces of the stopper core portion  21   c  (refer to  FIGS. 2 and 5 ). Accordingly, the stopper core portion  21   c  has superior workability. 
     As is apparent from  FIG. 7A , the covering  22 , which covers the stopper core portion  21   c  having the above-described configuration, is molded so that the thickness of the resin material differs between portions where the resin material covers the end faces Fb and the curved surfaces Fc and a substantially whole portion, which excludes the end faces Fb and the curved surfaces Fc. Namely, in the covering  22 , assuming that the thickness of the resin material which covers the substantially whole portion, which excludes the end faces Fb and the curved surfaces Fc, is t 0  (one example of a third thickness), the thickness of the resin material lying between the end faces Fb and the receiving surface Fa of the covering  22  becomes t 1  (one example of a first thickness) that is of the order of twice t 0 . Further, the thickness of the resin material lying between the curved surfaces Fc and the receiving surface Fa becomes t 2  (one example of a second thickness) that is larger than t 1 , because the curved surfaces Fc are curved towards the distal end at the portions where the resin material covers the curved surfaces Fc. Consequently, at the stopper portion  20   c , the covering  22  is molded so that the thickness of the resin material (the covering  22 ) which covers the stopper core portion  21   c  becomes the thickest, which is t 1  or t 2 , at the side which faces oppositely the holding member  10 . 
       FIG. 8  shows a side sectional view showing a state in which the door D is fully opened and the holding member  10  is brought into abutment with the stopper portion  20   c.    
     In the check link apparatus  1 , as shown in  FIG. 8 , when the door D is fully opened and the holding member  10  is brought into abutment with the stopper portion  20   c , that is, when the abutment surface  12   b  of the cover plate  12  of the holding member  10  is brought into abutment with the receiving surface Fa of the stopper portion  20   a , the sliders  15  of the holding member  10  are positioned on the third protuberant portion  22   e  which lies adjacent to the stopper portion  20   c . Namely, in the direction in which the holding member  10  moves on the arm  20 , a width W 0  defined between the abutment surface  12   b  of the cover plate  12  and end portions of the sliding elements  15  which lie to face the cover plate  12  is set smaller than a width W 1  defined between the receiving surface Fa of the stopper portion  20   c  and an end portion of the third protuberant portion  22   e  which lies to face the second recessed portion  22   d . By setting the widths in this way, the sliders  15  ride over an upwardly inclined surface  22   f , which slopes up from the second recessed portion  22   d  to the third protuberant portion  22   e , immediately before the holding member  10  comes into abutment with the stopper portion  20   c.    
     Incidentally, in a state where the door D is fully opened and the holding member  10  is brought to be in abutment with the stopper portion  20   c , the sliders  15  of the holding member  10  may be configured so as to be positioned on the upwardly inclined surface  22   f  which slopes up from the second recessed portion  22   d  to the third protuberant portion  22   e . As this occurs, the width W 0  is set larger than the width W 1  and smaller than a width W 2  defined between the receiving surface Fa and an end portion of the upwardly inclined surface  22   f  which lies to face the second recessed portion  22   d . Namely, the sliders  15  have come into sliding contact with the upwardly inclined surface  22   f  immediately before the holding member  10  comes into abutment with the stopper portion  20   c.    
       FIG. 9  is a plan view showing positions of the holding member  10  in relation to the arm  20  in the check link apparatus  1  when the door D is opened or closed. Incidentally, in  FIG. 9 , reference character Ch denotes the center of the door hinge Hj of the vehicle main body B. 
     Firstly, as in the arm  20  indicated by solid lines in  FIGS. 1 and 9 , when the door D is closed into the vehicle main body B, the check link apparatus  1  is disposed so that the sliders  15  of the holding member  10  fixed to the door D are positioned nearest to the pivot P while the sliders  15  are in sliding contact with the upper and lower surfaces of the arm  20 , that is, the holding member  10  is positioned farthest away from the stopper position  20   c . In this state, the arm  20  is disposed so as to extend along a front-to-rear direction of the vehicle main body B. 
     Next, when the door D is opened from the vehicle main body B from the state indicated by the solid lines in  FIG. 9 , in the check link apparatus  1 , the arm  20  rotates on an axis of the pivot P in a counterclockwise direction in  FIG. 9  as the door D is opened. Then, the holding member  10  moves along the arm  20  towards the stopper portion  20   c  in association with the rotation of the arm  20 . While the arm  20  and the holding member  10  are moving in the ways described above, the pair of sliders  15  move up and down to deform the pair of coil springs  16  elastically and appropriately in accordance with upper and lower surface configurations of the arm  20  while moving along the arm  20  in sliding contact with the upper and lower surfaces of the arm  20  by means of the spring force of the pair of coil springs  16 . 
     As a result of the movement thereof along the arm  20 , when the holding member  10  reaches the first check portion Pc 1  (the first recessed portion  22   b ), the pair of sliders  15  are restricted from moving from the first check portion Pc 1  by the spring force of the pair of coil springs  16  and by the shape of the recessed portion in the covering  22 . As a result of this, the arm  20  is stopped rotating together with the door D in an intermediate open position Pin shown in  FIG. 9  from the vehicle main body B. An opening angle of the door D with respect to the center Ch of the door hinge Hj then is denoted by reference character θ 1  in  FIG. 9 . 
     When the door D is opened further from the state in which the door D is opened at the opening angle θ 1 , the holding member  10  passes the second check portion Pc 2  (the second recessed portion  22   d ) on the arm  20  and eventually reaches the third protuberant portion  22   e  while the force with which the door D is opened is absorbed by the sliding contact of the holding member  10  with the upwardly inclined surface  22   f , whereby the cover plate  12  of the holding member  10  comes into abutment with the stopper portion  20   c  of the arm  20 . As a result, the arm  20  is stopped rotating together with the door D in a full open position Pfo shown in  FIG. 9  which lies farther away from the vehicle main body B than the intermediate open position Pm. In this state, the pair of sliders  15  are positioned on the third protuberant portion  22   e  by the spring force of the pair of coil springs  16  or the pair of sliders  15  are returned to the second check portion Pc 2  (the second recessed portion  22   d ) due to the reaction generated when the holding member  10  comes into abutment with the stopper portion  20   c , whereby the holding member  10  is restricted from moving further in the longitudinal direction of the arm  20 . As a result, the arm  20  is stopped rotating together with the door D in the full open position Pfo shown in  FIG. 9  which lies farther away from the vehicle main body B than the intermediate open position Pm. An opening angle of the door D with respect to the center Ch of the door hinge Hj then is denoted by reference character θ 2  in  FIG. 9 . 
     The cover plate  12  of the holding member  10  is in abutment with the stopper portion  20   c  of the arm  20  in the full open position Pfo, and therefore, the check link apparatus  1  is able to not only prevent the opening of the door D farther away from the vehicle main body B but also hold the door D in the full open position Pfo relative to the vehicle main body B. 
     On the other hand, when the door D is closed from the above-described full open position Pfo, the holding member  10  fixed to the door D moves along the arm  20  towards the bracket Bk while rotating the arm  20  on the axis of the pivot P via the pair of sliders  15 . While the holding member  10  and the arm  20  are moving in the ways described above, the pair of sliders  15  move up and down to deform the pair of coil springs  16  elastically and appropriately in accordance with upper and lower surface configurations of the arm  20  while moving along the arm  20  in sliding contact with the upper and lower surfaces of the arm  20  by means of the spring force of the pair of coil springs  16 . As a result of the movement thereof along the arm  20 , moving in an opposite way to the way in which the holding member  10  moves when the door D is opened, the holding member  10  moves from the second check portion Pc 2  to the position where the holding member  10  lies closest to the pivot P by way of the first check portion Pc 1 . 
     Thus, as has been described heretofore, in the check link apparatus  1  according to this embodiment, the stopper core portion  21   c  has the curved surfaces Fc at the end faces Fb that face oppositely the abutment surface  12   b  of the holding member  10  at least when the abutment surface  12   b  of the holding member  10  comes into abutment with the stopper portion  20   c.    
     In this way, by providing the curved surfaces Fc at the end faces Fb on the side of the stopper core portion  21   c  covered with the covering  22  with which the holding member  10  comes into abutment, even in the event that the holding member  10  comes into straight abutment with the stopper portion  20   c  (refer to  FIG. 7A ) or even in the event that the holding member  10  comes into offset abutment with the stopper portion  20   c  (refer to  FIG. 7B ), the load generated as a result of either of the abutments can be dispersed by the curved surfaces Fc when the load is applied between the resin material configuring the covering  22  and the curvilinear curved surfaces Fc provided at the end faces Fb, so that it makes possible to avoid the occurrence of a risk that the load is concentrated on a single point such as a corner portion. Therefore, it is possible to avoid an application of the concentrated load to the resin material which causes a crack in the resin material. Accordingly, it makes possible to prevent the separation of the covering  22  from the stopper core portion  21   c  to thereby configure the highly strong stopper portion  20   c.    
     In addition, the embodiment adopts the configuration in which the extensions L extending in the direction in which the load is applied to the stopper core portion  21   c  by the holding member  10  are positioned so as to pass the curved surfaces Fc of the stopper core portion  21   c  at least when the abutment surface  12   b  of the holding member  10  comes into abutment with the stopper portion  20   c . According thereto, the load applied to the stopper portion  20   c  when the abutment surface  12   b  of the holding member  10  comes into abutment with the stopper portion  20   c  can be dispersed by the curved surfaces Fc of the stopper core portion  21   c  in an ensured fashion. 
     The stopper portion  20   c  is made up of the stopper core portion  21   c  which is provided by expanding the other end of the arm core portion  21   a  in the width direction. Therefore, the stopper portion  20   c  can be formed only by cutting, for example, a single sheet of steel into the metal core  21  having the external shape shown in  FIG. 6 . Thus, the superior workability is realized, and the production costs can also be reduced. Moreover, the portions of the stopper core portion  21   c  corresponding to the receiving surface Fa, that is, the portions of the stopper core portion  21   c  which lie to face the holding member  10  are formed into the end faces Fb (the curved surfaces Fc) that are made up of the thickness-ways surfaces of the sheet of steel (the end faces of the sheet of steel), and the circular hole  26  is not positioned in the widthwise widened portions  24 . Therefore, the stopper core portion  21   c  becomes highly strong, and hence, the stopper core portion  21   c  can be restrained from being deformed when the holding member  10  is brought into abutment with the stopper portion  20   c , thereby making it possible to enhance the durability of the stopper core portion  21   c . In this way, at the stopper portion  20   c , the stopper core portion  21   c  is configured such that the deformation thereof is suppressed and the load from the holding member  10  is received by the curved surfaces Fc, thereby making it possible to prevent the separation of the resin material configuring the covering  22  in a more ensured fashion. 
     The circular hole  26  is formed in the stopper portion  20   c  so as to penetrate through the stopper core portion  21   c  so that the resin material configuring the covering  22  is filled therein. Therefore, in the stopper portion  20   c , the load from the holding member  10  can be received not only by the end faces Fb and the curved surfaces Fc but also by the inner circumferential surface of the circular hole  26 . Namely, the load receiving area of the stopper portion  20   c  is increased by the circular hole  26 . The circular hole  26  is positioned substantially in the center of the stopper core portion  21   c , for example. Consequently, the load applied from the holding member  10  to the resin material configuring the covering  22  can be dispersed in a better balanced fashion. Further, the coverings  22  of the resin material formed on the upper and lower surfaces of the stopper core portion  21   c  can be connected to each other by the circular hole  26 , and therefore, the separation of the resin material can be suppressed in a more ensured fashion. Incidentally, there may be configured such that a plurality of circular holes  26  is provided. In this case, for example, the plurality of circular holes  26  may be arranged so as to be symmetry with respect to a center line passing substantially central parts in width direction of the metal core  21  and extending along a longitudinal direction of the metal core  21 . The plurality of circular holes  26  may also be provided in the stopper core portion so as to be symmetry with respect to the center line. 
     In other words, in the stopper portion  20   c , the load applied from the holding member  10  to the resin material configuring the covering  22  is received by the curved surfaces Fc of the stopper core portion  21   c  to thereby be dispersed therefrom and is also received by the circular hole  26  to thereby be dispersed therefrom. Therefore, the large load receiving area can be ensured, and the load generated in this load receiving surface can be dispersed effectively. According thereto, the separation of the covering  22  can be prevented while receiving the holding member  10  in an ensured fashion, thereby making it possible to enhance the strength and durability of the stopper portion  20   c  further. Moreover, projections such as burrs are not left on the circumferential edge portions of the circular hole  26 , and the circumferential edge portions are made to be flush with or are depressed slightly further downwards than the upper and lower surfaces of the stopper core portion  21   c . In this way, in the event that no projections are left on the circumferential edge portions of the circular hole  26 , a large hole can be ensured within a range which is included in the widthwise dimension of the arm core portion  21   a , and therefore, the circular hole  26  is not positioned in the widthwise widened portions  24 . Thus, the load receiving area can be expanded while making the stopper core portion  21   c  highly strong. In addition, the load from the upper and lower portions of the opening  10   a  in the holding member  10  are applied uniformly to the upper and lower surfaces of the resin materials which lie above and below the circular hole  26 , and therefore, the applied load can be received in a well balanced fashion. 
     In the check link apparatus  1 , the arm portion  20   a  is formed by covering the arm core portion  21   a  with the resin material, and at least one set of a recessed portion and a protuberant portion on which the sliders  15  of the holding member  10  slide is formed on the arm portion  20   a  by the covering  22  (in this embodiment, in total two and half sets of recessed portions and protuberant portions including the set of the first protuberant portion  22   a  and the first recessed portion  22   b , the set of the second protuberant portion  22   c  and the second recessed portion  22   d , and the third protuberant portion  22   e ). In this configuration, the abutment surface  12   b  of the holding member  10  is brought into abutment with the stopper portion  20   c  when the sliders  15  of the holding member  10  are positioned on the upwardly inclined surface  22   f  which slopes up from the second recessed portion  22   d  to the third protuberant portion  22   e  or on the third protuberant portion  22   e  (refer to  FIG. 8 ). By adopting this configuration, the holding member  10  receives a force acting thereon in an opposite direction to the moving direction thereof by means of the sliding contact action between the sliders  15  and the upwardly inclined surface  22   f . According thereto, the load transmitted from the holding member  10  to the stopper portion  20   c  is suppressed, and the damage to the stopper portion  20   c  and the generation of impact noise can be reduced, thereby making it possible to prevent the separation of the resin material configuring the covering  22  in a more ensured fashion. 
     In the check link apparatus  1 , the thickness of the resin material that covers the stopper core portion  21   c  is formed so that the thickness of the resin material at the end facing the holding member  10  becomes t 1  or t 2  which is the thickest (refer to  FIG. 7A ). Therefore, while avoiding the enlargement of the stopper portion  20   c , the resin material configuring the covering  22  is allowed to be deformed to thereby act as a cushion to receive the load from the holding member  10  when the stopper portion  20   c  receives the load from the holding member  10 . Thus, the separation of the resin material can be suppressed in a more ensured fashion. 
     The invention is not limited to the embodiment that has been described heretofore and can, of course, be modified freely without departing from the spirit and scope of the invention. 
     For example, in the above-described embodiment, the holding member  10  is mounted on the door D and the connecting portion  20   b  is supported rotatably on the bracket Bk provided on the vehicle main body B. Alternatively, a configuration may be adopted in which the holding member  10  is provided on the vehicle main body B, while the connecting portion  20   b  is supported rotatably on the door D. 
     In addition, in the above-described embodiment, while the check link apparatus  1  is illustrated in which the widthwise widened portions  24  which configure the stopper core portion  21   c  are disposed in the width direction, the orientation of the arm  20  may be changed as required depending upon models on which the check link apparatus  1  is installed, and the widthwise widened portions  24  may, of course, be used in a vertical direction or in an inclined posture.