Patent Publication Number: US-7913361-B2

Title: Door handle device

Description:
TECHNICAL FIELD 
     The present invention relates to an improved door handle system, which is incorporated in an automotive door, and which prevents a door opening lever from swiftly returning to a position prior to pulling operation when stopping the pulling operation to the door opening lever for opening the door. 
     BACKGROUND ART 
     The door opening lever of an automotive door is configured to be linked to the door latch of the door so that the door latched by the door latch is capable of being released from a closed state by pulling operation. The door opening lever is configured to be biased to be returned to a position prior to pulling operation by a spring when the pulling operation is stopped. If the door opening lever is returned under the biasing action of the spring without being damped when the pulling operation is stopped, the automobile is subjected to trouble, such as the generation of an impulsive sound, damaging the quality image of the automobile. From this point of view, it has been proposed to dispose a buffer in the form of bellows so as to extend between a bracket disposed in a door and an internal end of a door opening lever disposed at a deeper position of the door than the swingable shaft for the door opening lever, and to utilize air resistance to slowly collapse the bellows so as to damp the returning action of the door opening lever when the bellows is expanded by pulling operation, followed by stopping the pulling operation (see Patent Document 1). 
     The system disclosed by Patent Document 1 is configured so that a first pair of one end of the buffer and the internal end of the door opening lever, and a second pair of the other end of the buffer and the bracket are coupled by shafts, respectively. If an internal part in the door is frozen in, e.g. midwinter, there has been a case where these coupled portions are fixedly coupled together to make the pulling operation of the door opening lever difficult.
     Patent Document 1: JP-B-2-35107   

     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     It is a main object of the present invention to provide a door handle system with a damping function, which is capable of adequately damping the returning action of a door opening lever to a position prior to pulling operation by a biasing force when stopping the pulling operation to the door opening lever, and which is capable of performing the pulling operation or the like for the door opening lever without trouble even if an internal part is frozen in the door. 
     Means to Solve the Problem 
     In order to attain the above-mentioned object, according to a first aspect of the present invention, there is provided a door handle system, which comprises: 
     (1) a door opening lever swingably assembled to a door panel and configured to be linked to a door latch so as to open a door by pulling operation; 
     (2) a damper including a cylinder, a piston, a piston rod and a biasing member for constantly biasing the piston in a direction away from a depth end of the cylinder, the damper being configured so as to provide a resistance of a fluid to a retracting movement of the piston against the biasing action, the fluid being sealed in the cylinder; and 
     (3) a housing for the damper, fixed to the door panel; 
     (4) wherein the door opening lever has an operating part formed on one end thereof and a pressing part formed on the other end thereof with respect to a swingable shaft, the pressing part having a cam surface, the cam surface being configured so as to have a distance from the swingable shaft gradually increasing toward a cam end; 
     (5) wherein the damper is configured so that the piston rod is fixed to a depth end of the housing, that a gap is formed between an outer wall of the cylinder and an inner wall of the housing, and that the cylinder has a depth end constantly brought into press-contact with the cam surface of the door opening lever under the biasing action; and 
     (6) wherein the damper is configured so that a portion of the cam surface close to the cam end is brought into press-contact with the depth end of the cylinder to retract the piston into the cylinder at a maximum when the door opening lever is not subjected to pulling operation. 
     In accordance with the first aspect of the present invention, when the door opening lever is pulled, such a portion of the cam surface close to the swingable shaft is positioned in front of the depth end of the cylinder with the result that the cylinder moves forward, i.e. moves in a direction to protrude from the housing under the biasing action of the biasing member, following the swinging operation of the door opening lever. The damper applies no damping force to the pulling operation. When the pulling operation of the door opening lever is stopped, the door opening lever is returned to such a position prior to pulling operation. When the door opening lever is returned to such a position prior to pulling operation, such a portion of the cam surface close to the cam end is positioned in front of the depth end of the cylinder with the result that the cylinder is retracted, i.e. is moved in a direction to be pressed into the housing against the biasing action of the biasing member. In this time, the damper applies a damping force to make the returning movement of the door opening lever slow. Even if an internal part in the door handle system is frozen, not only the door opening lever can be pulled without trouble but also the damper can be operated without trouble since the depth end of the cylinder forming the damper is simply brought into contact with the cam surface of the door opening lever and since the gap is formed between the outer wall of the cylinder and the inner wall of the housing. 
     In the door handle system according to the first aspect of the present invention, at least the depth end of the cylinder may be formed of a plastic material having a small friction coefficient. In this case, even if the depth end of the cylinder is constantly brought into press-contact with the cam surface of the pressing part of the door opening lever, the door opening lever is not prevented from swinging. 
     In order to attain the above-mentioned object, according to a second aspect of the present invention, there is provided a door handle system, which comprises: 
     (1) a door opening lever swingably assembled to a door panel and configured to be linked to a door latch so as to open a door by pulling operation; 
     (2) a damper including a cylinder, a piston, a piston rod and a biasing member for constantly biasing the piston in a direction away from a depth end of the cylinder, the damper being configured so as to provide a resistance of a fluid to a retracting movement of the piston against the biasing action, the fluid being sealed in the cylinder; and 
     (3) a support for the damper, fixed to the door panel; 
     (4) wherein the door opening lever has an operating part formed on one end thereof and a pressing part formed on the other end thereof with respect to a swingable shaft, the pressing part having a cam surface, the cam surface being configured so as to have a distance from the swingable shaft gradually increasing toward a cam end; 
     (5) wherein the damper is configured so that the cylinder is fixed to the support, and that the piston rod has an outer end constantly brought into press-contact with the cam surface of the door opening lever under the biasing action; and 
     (6) wherein the damper is configured so that a portion of the cam surface close to the cam end is brought into press-contact with the outer end of the cylinder to retract the piston into the cylinder at a maximum when the door opening lever is not subjected to pulling operation. 
     In accordance with the second aspect of the present invention, when the door opening lever is pulled, such a portion of the cam surface close to the swingable shaft is positioned in front of the outer end of the piston rod with the result that the piston rod moves forward, i.e. moves in a direction to protrude from the support under the biasing action of the biasing member, following the swinging operation of the door opening lever. The damper applies no damping force to the pulling operation. When the pulling operation of the door opening lever is stopped, the door opening lever is returned to such a position prior to pulling operation. When the door opening lever is returned to such a position prior to pulling operation, such a portion of the cam surface close to the cam end is positioned in front of the outer end of the piston rod with the result that the piston rod is retracted against the biasing action of the biasing member. In this time, the damper applies a damping force to make the returning movement of the door opening lever slow. Even if an internal part in the door handle system is frozen, not only the door opening lever can be pulled without trouble but also the damper can be operated without trouble since the outer end of the piston rod forming the damper is simply brought into contact with the cam surface of the door opening lever and since the piston rod is not brought into contact with the support. 
     In order to attain the above-mentioned object, according to a third aspect of the present invention, there is provided a door handle system, which comprises: 
     (1) a door opening lever swingably assembled to a door panel and configured to be linked to a door latch so as to open a door by pulling operation; 
     (2) a linearly moving member supported by the door panel, the linearly moving member being configured so as to move back and forth; 
     (3) a biasing member for the linearly moving member; and 
     (4) a damper including a main body and a pinion rotatably supported by the main body, the damper being configured so as to provide a resistance of a fluid to a rotation of the pinion, the fluid being sealed in the main body; 
     (5) wherein one of the linearly moving member and the door panel has the damper fixed thereto, and the other is formed with a rack engageable with the pinion forming the damper; 
     (6) wherein the door opening lever has an operating part formed on one end thereof and a pressing part formed on the other end thereof with respect to a swingable shaft, the pressing part having a cam surface, the cam surface being configured so as to have a distance from the swingable shaft gradually increasing toward a cam end; 
     (7) wherein the linearly moving member has a front end constantly brought into press-contact with the cam surface of the door opening lever under a biasing action of the biasing member; and 
     (8) wherein the door opening lever is configured so that a portion of the cam surface close to the cam end is brought into press-contact with the front end of the linearly moving member to retract the linearly moving member at a maximum when the door opening lever is not subjected to pulling operation. 
     In accordance with the third aspect of the present invention, when the door opening lever is pulled, such a portion of the cam surface close to the swingable shaft is positioned in front of the front end of the linearly moving member with the result that the linearly moving member moves forward under the biasing action of the biasing member, following the swinging operation of the door opening lever. The damper applies no damping force to the pulling operation. When the pulling operation of the door opening lever is stopped, the door opening lever is returned to such a position prior to pulling operation. When the door opening lever is returned to such a position prior to pulling operation, such a portion of the cam surface close to the cam end is positioned in front of the front end of the linearly moving member with the result that the linearly moving member is retracted against the biasing action of the biasing member. In this time, the rotation of the pinion caused by the retracting movement is damped by the fluid with the result that the returning movement of the door opening lever is made slow. Even if an internal part in the door handle system is frozen, not only the door opening lever can be pulled without trouble but also the damper can be operated without trouble since the front end of the linearly moving member forming the damper is simply brought into contact with the cam surface of the door opening lever. 
     EFFECTS OF THE INVENTION 
     The door handle system according to the present invention is configured not only to adequately damp the returning movement of the door opening lever to the position prior to pulling operation when stopping the pulling operation to the door opening lever but also to simply press the cylinder or the like forming the damper to the pressing part of the door opening lever under the biasing action of the biasing member. In accordance with the door handle system of the present invention, even if an internal part in the door is frozen, it is possible to perform the pulling operation or the like for the door opening lever without trouble since the pressed portions are prevented from being fixed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view showing the structure of the door handle system according to a first embodiment of the present invention; 
         FIG. 2  is a cross-sectional view showing the structure of the door handle system according to the first embodiment; 
         FIG. 3  is another cross-sectional view showing the structure of the door handle system according to the first embodiment; 
         FIG. 4  is a cross-sectional view showing the structure of a damper; 
         FIG. 5  is a perspective view showing the structure of a piston; 
         FIG. 6  is a cross-sectional view taking along line A-A of  FIG. 5 ; 
         FIG. 7  is a front view showing the structure of the door handle system according to a second embodiment of the present invention; 
         FIG. 8  is a cross-sectional view showing the structure of the door handle system according to the second embodiment; 
         FIG. 9  is a front view showing the structure of the door handle system according to a third embodiment of the present invention; and 
         FIG. 10  is a cross-sectional view showing the structure of the door handle system according to the third embodiment. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Now, embodiments for carrying out the present invention will be described on the basis of  FIG. 1  to  FIG. 10 . 
       FIG. 1  to  FIG. 3  show the door handle system according to a first embodiment,  FIG. 7  and  FIG. 8  show the door handle system according to a second embodiment, and  FIG. 9  and  FIG. 10  show the door handle system according to a third embodiment.  FIG. 3 ,  FIG. 8  and  FIG. 10  show that door opening levers  2  have been pulled in the respective embodiments.  FIG. 4  shows the internal structure of a damper  7  according to the first embodiment and the second embodiment.  FIG. 5  and  FIG. 6  show a piston  71  forming the damper  7 . 
     The door handle system according to these embodiments is applicable as an inside door handle system disposed at the interior side of an automotive door or as an outside door handle system disposed at the exterior side of an automotive door. The door handle system is configured so that the door opening lever  2  forming a part of the door handle system is prevented from swiftly returning to a position prior to pulling operation when stopping the pulling operation to the door opening lever  2 . 
     The door opening lever  2  is swingably assembled to a door panel  1 . The door opening lever is linked to a door latch so as to be capable of opening the door by pulling operation. 
     The door opening lever  2  has an operating part  2   b  formed on one end thereof and a pressing part  2   c  formed on the other end thereof with respect to a swingable shaft  2   a.    
     In each of the shown embodiments, the door opening lever  2  forms a part of an inside door handle system. The swingable shaft  2   a  of the door opening lever  2  is disposed to extend vertically and is configured to have the operating part  2   b  pulled by engaging fingers with the operating part  2   b  from above at the position prior to pulling operation. The door opening lever  2  is biased to be positioned at the position prior to pulling operation by, e.g. an unshown torsion coil spring. In each of the shown embodiments, when the door opening lever  2  is pulled against the biasing action of the torsion coil spring, a connecting rod  5 , which is coupled to the pressing part  2   c  of the door opening lever  2 , is pulled, causing the door latched by an unshown door latch to be released from an closed state. 
     In each of the shown embodiments, specifically, the door handle system includes an inner frame  3  and an outer frame  4 , which are disposed inside the door panel  1 , or an inner panel  1   a  in each of the shown embodiments. The outer frame  4  is formed in a substantially box shape with a front side opened and has the opened side formed with a peripheral flange  4   a . The outer frame  4  is mounted to the door so as to have an inner portion inside the peripheral flange accommodated inside the inner panel  1   a , i.e. in an inner space  1   c  of the door in such a state that the peripheral flange  4   a  is brought into press-contact with an edge of a mounting hole  1   b  formed in the inner panel  1   a . The outer frame  4  has an outer profile and an inner profile, which are formed in a substantially rectangular shape elongated in a width direction of the door. At a position close to one side of the outer frame  4  (a right side of the outer frame in each of the shown embodiments) extending in a width direction thereof, the swingable shaft  2   a  is supported by the outer frame  4  in such a state that the swingable shaft has a top end fixed to an upper wall  4   b  of the outer frame  4  and a bottom end fixed to a lower wall  4   c  of the outer frame  4 , and has an intermediate portion positioned in the outer frame  4 . The operating part  2   b  of the door opening lever  2  has a length extending throughout a lower portion of the outer frame  4  in the outer frame  4  and is of such a size as to close the lower portion of the outer frame  4  in the position prior to pulling operation. The pressing part of the door opening lever  2  is configured so as to project toward the inner space of the door from the rear side of one end of the operating part  2   b . The operating part  2   b  and the pressing part  2   c  are connected together at a connecting part, which has a shaft hole  2   f  vertically formed therethrough. By putting the intermediate portion of the swingable shaft  2   a  in the shaft hole  2   f , the door opening lever  2  is swingably assembled to the outer frame  4 , consequently to the door panel  1 . 
     On the other hand, the inner frame  3  is formed in a substantially box shape with a front side opened and is disposed in the inner space of the door so as to have the opening edge brought into press-contact with the edge of the mounting hole  1   b  from an interior side of the inner panel  1   a . The inner portion of the outer frame  4  inside the peripheral flange  4   a  is accommodated in the inner frame  3 . The outer frame  4  and the inner frame  3  have windows  4   d  and  3   d  formed in recessed walls thereof so as to allow the pressing part  2   c  to move therethrough when pulling the door opening lever  2 . In the figures, reference numeral  6  designates a lock-nut 
     The pressing part  2   c  of the door opening lever  2  has a surface formed as a cam surface  2   d  thereon so as to face a right wall  4   e  before the door opening lever is pulled, the surface extending along the width direction of the outer frame  4 . The cam surface  2   d  is configured so as to have a distance from the swingable shaft  2   a  gradually increasing toward a cam end  2   e , i.e. the distal end of the pressing part  2   c . When the door opening lever  2  is set at the position prior to pulling operation, the cam end  2   e  is set at a position in front of an inlet  9   b  of a housing  9  for the damper  7  in the first embodiment described later, at a position in front of an inlet lob of a support  10  for the damper  7  in the second embodiment described later, and at a position in front of an front end of a linearly moving member  11  in the third embodiment described later. 
     First Embodiment 
       FIG. 1  to  FIG. 6  show an embodiment wherein the door handle system includes the damper  7  and the housing  9  for the damper  7  as not in the other embodiments. 
     The damper  7  includes a cylinder  70 , the piston  71 , a piston rod  72  and a biasing member  73  for constantly biasing the piston  71  in a direction away from a depth end  70   a  of the cylinder  70 . The damper  7  is configured so as to provide the resistance of a fluid to the retracting movement of the piston  71  against the biasing action, the fluid being sealed in the cylinder  70 . Typical examples of the fluid include a viscous fluid, such as silicone oil, or a gas, such as air. In the shown embodiment, an unshown viscous fluid is sealed in the cylinder  70 . 
     The cylinder  70  is formed in a substantially cylindrical shape and has one end opened and the other end closed, the other end forming the depth end  70   a  of the cylinder  70 . The depth end  70   a  of the cylinder  70  is formed with a semispherical portion  70   b . In the shown embodiment, the semispherical portion  70   b  has a top end constantly brought into press-contact with the cam surface  2   d  of the pressing part  2   c  of the door opening lever  2  under the biasing action of the biasing member  73 . The semispherical portion  70   b  is formed of a plastic material having a small friction coefficient. The semispherical portion is configured so as not to prevent the door opening lever  2  from swinging, being constantly brought into press-contact with the cam surface  2   d  of the pressing part  2   c  of the door opening lever  2 . 
     The piston rod  72  has an inner end  72   a  (a rod end positioned in the cylinder  70 ) formed with a cap  74 . The piston rod  72  has an intermediate portion formed with a peripheral flange  72   b , which is spaced from the cap  74 . The piston  71  is formed in such a cylindrical shape that a through hole  71   a  is formed in a central portion to pass the piston rod  72  therethrough. The piston is disposed between the cap  74  and the peripheral flange  72   b , having the piston rod  72  passing through the through hole  71   a . The piston  71  has a pitch between the cap  74  and the peripheral flange  72   b , which is longer than the entire length of the piston. The piston  71  is configured so that when the piston rod  72  is retracted or relatively retracted into the cylinder  70 , the piston is seated against the peripheral flange  72   b  by the fluid, and that when the piston rod  72  is extended or relatively extended from the cylinder  70 , the piston is separated from the peripheral flange  72   b  by the fluid. 
     The through hole  71   a  of the piston  71  is configured so as to have a larger diameter at an end close to the peripheral flange  72   b  (hereinbelow, referred to as the rear end  71   b  of the piston  71 ) than the piston rod  72 . The rear end  71   b  of the piston  71  has an outline formed in a disc shape in section extending in a direction perpendicular to the central axis thereof, the disc shape having an outer diameter substantially equal to the inner diameter of the cylinder  70 . In the rear end  71   b  of the piston  71 , the through hole  71   a  is configured so as to be closed by the peripheral flange  72   b  when the piston is seated against the peripheral flange. The piston is configured so as to have a small diameter portion  71   c  between the rear end  71   b  of the piston  71  and an end close to the cap  74  of the piston  71  (hereinbelow, referred to as the leading edge of the piston  71 ), the small diameter portion being smaller than the inner diameter of the cylinder  70 . The small diameter portion  71   c  has a connection portion with the rear end  71   b , formed with a window  71   d  communicating with the through hole  71   a . The rear end  71   b  of the piston  71  has a lateral surface formed with a narrow groove  71   e  at each side in the diameter direction. The piston is configured so as to allow the fluid to move through an orifice defined by the narrow groove  71   e  and the inner wall of the cylinder  70  when the piston is seated against the peripheral flange. 
     In the shown embodiment, the biasing member  73  is formed of a helical compression spring housed between the cap  74  and the inner wall of the depth end  70   a  of the cylinder  70 . The open end of the cylinder  70  is closed by an end cap  75 , which has a through hole formed in a central portion thereof to pass the piston rod  72  therethrough. The cylinder  70  has a stepped portion  70   c  at a portion close to the open end. The cylinder has an inner liner  76  inserted so as to have a depth end brought into press-contact with the stepped portion, the inner liner housing an accumulator  76   a  formed of a foamed plastic material. The cylinder has an oil seal  77  interposed between the inner liner  76  and the end cap  75  therein. The piston rod  72  is configured so as to extend out of the cylinder  70  to a position to bring the peripheral flange  72   b  into press-contact with the inner liner  76  at the maximum under the biasing action of the spring. 
     In the shown embodiment, when the piston rod  72  is extended or relatively extended out of the cylinder  70  under the biasing action the spring, the piston  71  is separated from the peripheral flange  72   b  by the resistance of the fluid, and the fluid moves through the window  71   d . Thus, the damping force applied at the time of extending the piston rod is made small. On the other hand, when the piston rod  72  is retracted or relatively retracted into the cylinder  70  against the biasing action of the spring, the piston is seated against the peripheral flange  72   b  by the resistance of the fluid, and the fluid moves only through the orifice. Thus, the damping force is made great. 
     In the shown embodiment, the housing  9  for the damper  7  is fixed to the door panel  1 . In the shown embodiment, the housing  9  is formed of a cylindrical body  9   a , which has one end opened and the other end closed, the open end communicating with a space in the inner frame  3 . The open end of the cylindrical body  9   a  serves as the inlet  9   b  of the housing  9 . The damper  7  is accommodated in the housing  9 , the piston rod  72  having an outer end  72   c  fixed to a depth end of the housing  9 , i.e. the other end of the cylindrical body  9   a . The cylindrical body  9   a  has an inner diameter set to be larger than the outer diameter of the cylinder  70 . The damper  7  is supported only by fixture of the outer end  72   c  of the piston rod  72  so that the damper has a gap  9   c  formed along the entire circumference of the cylinder  70  between the outer wall of the cylinder  70  and the inner wall of the housing  9 . The depth end  70   a  of the cylinder  70  of the damper  7 , which is supported as described above, is constantly brought into press-contact with the cam surface  2   d  of the door opening lever  2  under the above-mentioned biasing action. Further, the damper is configured so that a portion of the cam surface  2   d  close to the cam end  2   e  is brought into press-contact with the depth end  70   a  of the cylinder  70  to retract the piston  71  into the cylinder  70  at the maximum when the door opening lever  2  is not subjected to pulling operation (see  FIG. 2 ). 
     In the shown embodiment, when the door opening lever  2  is pulled, a portion of the cam surface  2   d  close to the swingable shaft  2   a  is positioned in front of the depth end  70   a  of the cylinder  70  with the result that the cylinder  70  moves forward, i.e. moves in a direction to protrude from the housing  9  under the biasing action of the biasing member  73 , following the swinging operation of the door opening lever. The damper applies no damping force to the pulling operation  7 . When the pulling operation of the door opening lever  2  is stopped, the door opening lever  2  is returned to a position prior to pulling operation. When the door opening lever is returned to the position prior to pulling operation, such a portion of the cam surface  2   d  close to the cam end  2   e  is positioned in front of the depth end  70   a  of the cylinder  70  with the result that the cylinder  70  is retracted, i.e. is moved in a direction to be pressed into the housing  9  against the biasing action of the biasing member  73 . In this time, the piston  71  is seated against the peripheral flange  72   b  with the result that the damper  7  applies a damping force to make the returning movement of the door opening lever  2  slow. Even if an internal part in the door handle system is frozen, not only the door opening lever  2  can be pulled without trouble but also the damper  7  can be operated without trouble since the depth end  70   a  of the cylinder  70  forming the damper  7  is simply brought into contact with the cam surface  2   d  of the door opening lever  2  and since the gap  9   c  is formed between the outer wall of the cylinder  70  and the inner wall of the housing  9 . In other words, it is possible to prevent the door opening lever  2  from being fixed to the cylinder  70  and prevent the cylinder  70  from being fixed to the housing  9  even if an internal part in the door handle system is frozen. 
     Second Embodiment 
       FIGS. 7 and 8  show an embodiment wherein the door hand system includes the damper  7  and the support  10  for the damper  7 . 
     In the second embodiment shown, the damper  7  has the same structure as the damper according to the first embodiment. In the second embodiment, the support  10  for the damper  7  is fixed to the door panel  1 . In the second embodiment, the support  10  is formed of a cylindrical body  10   a , which has one end opened and the other end closed, the open end communicating with the space in the inner frame  3 . The open end of the cylindrical body  10   a  serves as the above-mentioned inlet  10   b  of the support  10 . The damper  7  is accommodated in the support  10  so that the cylinder  70  is fitted into the support  10  through the inlet  10   b  of the support  10 , having its depth end set in a deep position, and that the outer end  72   c  of the piston rod  72  protrudes from the inlet  10   b  of the support  10  into the space in the inner frame  3 . The cylindrical body  10   a  has an inner diameter set to be substantially equal to the outer diameter of the cylinder  70 . The outer end  72   c  of the piston rod  72  of the damper  7 , which is supported as described above, is constantly brought into press-contact with the cam surface  2   d  of the door opening lever  2  under the above-mentioned biasing action. Further, the damper is configured so that a portion of the cam surface  2   d  close to the cam end  2   e  is brought into press-contact with the outer end  72   c  of the piston rod  72  to retract the piston  71  into the cylinder  70  at the maximum when the door opening lever  2  is not subjected to pulling operation (see  FIG. 7 ). 
     In the second embodiment, when the door opening level  2  is pulled, a portion of the cam surface  2   d  close to the swingable shaft  2   a  is positioned in front of the outer end  72   c  of the piston rod  72  with the result that the piston rod  72  moves forward, i.e. moves in a direction to protrude from the support  10  under the biasing action of the biasing member, following the swinging operation of the door opening lever. The damper  7  applies no damping force to the pulling operation. When the puling operation applied to the door opening lever  2  is stopped, the door opening lever  2  is retuned to a position prior to pulling operation. When the door opening lever is returned to the position prior to pulling operation, such a portion of the cam surface  2   d  close to the cam end  2   e  is positioned in front of the outer end  72   c  of the piston rod  72  with the result that the piston rod  72  is retracted, i.e. is moved in a direction to be pressed into the support  10  against the biasing action of the biasing member  73 . In this time, the piston  71  is seated against the peripheral flange  72   b  with the result that the damper  7  applies a damping force to make the returning movement of the door opening lever  2  slow. Even if an internal part in the door hand system is frozen, not only the door opening lever  2  can be pulled without trouble but also the damper  7  can be operated without trouble since the outer end  72   c  of the piston rod  72  forming the damper  7  is simple brought into contact with the cam surface  2   d  of the door opening lever  2  and since the piston rod  72  is not brought into contact with the support  10 . In other words, it is possible to prevent the door opening lever  2  from being fixed to the outer end  72   c  of the piston rod  72  and prevent the piston rod  72  from being fixed to the support  10 . 
     Third Embodiment 
       FIG. 9  and  FIG. 10  show an embodiment wherein the door hand system includes the linearly moving member  11 , a biasing member for the linearly moving member  11 , and a damper  8 . 
     In the third embodiment shown, the linearly moving member  11  is formed in a bar shape. The linearly moving member  11  is configured so as to have one end portion (front end portion  11   a ) passing through a through hole  3   b  formed in the inner frame  3  to be supported by the inner wall of the through hole and to move back and forth, varying a protruding length from the through hole  3   b , i.e. performing a linear movement. In the third embodiment shown, the linearly moving member  11  has the other end portion formed with a rack  11   a  having a length of not less than the displacement stroke of the linearly moving member  11 . 
     The damper  8  is configured so as to include a main body  8   a  fixed to the door panel  1  and a pinion  8   b  rotatably supported by the main body  8   a  and to provide the resistance of a viscous fluid, such as silicon oil to the rotation of the pinion  8   b , the fluid being sealed in the main body  8   a . The damper  8  is fixed in such a position that the pinion  8   b  is constantly engaged with the rack  11   a  of the linearly moving member  11 . In the third embodiment, the damper  8  has an unshown torsion coil spring incorporated thereinto to bias the pinion in a direction to constantly press the linear moving member  11  forward. In the third embodiment show, the pinion is counterclockwise biased. Thus, the linearly moving member  11  has the front end portion  11   a  constantly brought into press-contact with the cam surface  2   d  of the door opening lever  2 . In other words, in the third embodiment, the unshown spring of the damper  8  serves as the above-mentioned biasing member. 
     In the third embodiment, the damper is configured so that a portion of the cam surface  2   d  close to the cam end  2   e  is brought into press-contact with the front end portion  11   a  of the linearly moving member  11  to retract the linearly moving member  11  at the maximum when the door opening lever  2  is not subjected to pulling operation (see  FIG. 9 ). 
     In the third embodiment, when the door opening lever  2  is pulled, a portion of the cam surface  2   d  close to the swingable shaft  2   a  is positioned in front of the front end  11   a  of the linearly moving member  11  with the result that the linearly moving member  11  moves forward under the biasing action of the biasing member, following the swingable operation of the door opening lever. The damper  8  applies no damping force to the pulling operation. In order to cause the linearly moving member  11  to move forward so as to follow the swinging operation of the door opening lever without time lag, it is preferred that the resistance of the fluid be prevented from being strongly applied to the pinion  8   b  of the damper when the pinion  8   b  is rotated in a direction to cause the forward movement. When the pulling operation of the door opening lever  2  is stopped, the door opening lever  2  is returned to a position prior to pulling operation. When the door opening lever is returned to the position prior to pulling operation, such a portion of the cam surface  2   d  close to the cam end  2   e  is positioned in front of the front end  11   a  of the linearly moving member  11  with the result that the linearly moving member  11  is retracted against the biasing action of the biasing member. In this time, the rotation of the pinion  8   b  caused by the retracting movement is damped by the fluid with the result that the returning movement of the door opening lever  2  is made slow. Even if an internal part in the door handle system is frozen, not only the door opening lever  2  can be pulled without trouble but also the damper  8  can be operated without trouble since the front end  11   a  of the linearly moving member  11  forming the damper  8  is simply brought into contact with the cam surface  2   d  of the door opening lever  2 . In other words, it is possible to prevent the door opening lever  2  from being fixed to the front end  11   a  of the linearly moving member  11  even if an internal part in the door handle system is frozen. 
     The entire disclosure of Japanese Patent Application No. 2006-026123 filed on Feb. 2, 2006 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.