Patent Publication Number: US-7581767-B2

Title: Door closing device

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a door closing device in a vehicle and particularly to a door closing device in a vehicle, having a latch engagable with a striker of the vehicle to enable the latch to move from a half-latched position to a full-latched position. 
     In a conventional door closing device, for example, as disclosed in U.S. Pat. No. 5,466,021A to Ishihara et al., closing of a door allows a latch engagable with a striker fixed to a vehicle to move from an open position to a half-latched position. A half-latch detecting sensor detects the half-latched position to enable a passive lever to move from an original position in a closing direction by a motor thereby moving the latch in the half-latched position to a full-latched position with the move to the closing direction. After the latch is moved to the full-latched position, the passive lever is reversely rotated towards the original position by the motor. 
     However, in the door closing device in the US patent, for example, owing to wrong detection of the half-latch detecting sensor, the latch is moved from the open position to the full-latched position after the passive lever is moved from the original position in the closing direction by the motor. The latch engages with the passive lever to make it impossible for the passive lever to return to the original position. Such wrong operation is likely to cause damage such as deformation on the engagement portion to result in malfunction in the operation. 
     Also, in the structure in which the latch can be released from a striker by moving the passive lever from the original position to the releasing direction opposite to the closing direction, wrong operation likely makes the door difficult to open. 
     SUMMARY OF THE INVENTION 
     In view of the disadvantages in the prior art, it is an object of the invention to provide a door closing device that prevents each part from being damaged even if wrong operation occurs, making normal operation more secure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features and advantages of the invention will become more apparent from the following description with respect to embodiments as shown in the accompanying drawings wherein: 
         FIG. 1  is a perspective view of a door closing device according to the present invention; 
         FIG. 2  is a front elevational view of the door closing device; 
         FIG. 3  is a plan view of the door closing device; 
         FIG. 4  is a plan view of the engagement structure when a latch is in an open position; 
         FIG. 5  is a plan view of the engagement structure when the latch is in a half-latched position; 
         FIG. 6  is a plan view of the engagement structure when the latch is in a full-latched position; 
         FIG. 7  is a plan view of the engagement structure when the latch is in an open position in malfunction; 
         FIG. 8  is a plan view of the engagement structure when the latch is in a full-latched position in malfunction; 
         FIG. 9  is a front view of a closing portion when a sector gear and a closing lever are in an original position; 
         FIG. 10  is a front view of the closing portion when the sector gear and closing lever are moved in a closing direction; 
         FIG. 11  is a front view of the closing portion when the sector gear is moved in a releasing direction; 
         FIG. 12  is a front view of the closing portion at the beginning of malfunction; 
         FIG. 13  is a front view of the closing portion in malfunction; 
         FIG. 14  is a front view of the closing portion in another embodiment; and 
         FIG. 15  is a front view of the closing portion in malfunction in the embodiment in  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     An embodiment of the present invention will be described with respect to  FIGS. 1 to 13 . In the description below, the left lower side in  FIG. 1 , front in  FIG. 2  and lower side in  FIG. 3  are deemed the front, while the right upper side in  FIG. 1 , reverse side in  FIG. 2  and upper side in  FIG. 3  are deemed the rear. 
     A door closing device is provided at the lower end of a tailgate (not shown) hinged on a shaft (not shown) at the upper end on the back of a vehicle to enable the tailgate to open or close up and down. The door closing device comprises an engagement portion  3  that engages with a striker  2  fixed to a vehicle to hold the tailgate in a closed position, and a closing portion  4  thereby enabling the tailgate to move from an incompletely-closed position to a full-closed position by a motor  42 . 
       FIGS. 4-6  are plan views showing normal operation of the engagement portion  3 , and  FIGS. 7 and 8  show abnormal operation thereof. The engagement portion  3  comprises a box-like latch housing  31  fixed to the lower end of the tailgate; a latch  33  pivoted to a vertical pivot  32  in the latch housing  31  to engage with the striker  2 ; a locking plate  35  pivoted on a vertical pivot  34  in the latch housing  31 ; and a latch lever  36  that can turn on the pivot  32  together with the latch  33 . 
     As the tailgate is closed, the latch  33  turns from an open position in  FIGS. 4 and 7  in which the latch  33  disengages from the striker  2  to allow the tailgate to open, to a full-latched position in  FIGS. 3 ,  6  and  8  in which the latch  33  completely engages with the striker  2  to allow the tailgate to close completely, via a half-latched position in  FIG. 5  in which the latch  33  incompletely engages with the striker  2  to allow the tailgate to close imcompletely. 
     The latch lever  36  has a cylindrical engagement portion  36   a  projecting upwards from a free end and rotates together with the latch  33  from the open position in  FIGS. 4 and 7  to the full-latched position in  FIGS. 3 ,  6  and  8  via the half-latched position in  FIG. 5 . 
     The engagement portion  36   a  is positioned at the side of the pivot  32  when the latch  33  is in the open position, turns at about  45  degrees rearwards from the open position in the half-latched position, and is positioned right behind the pivot  32  in the full-latched position. The engagement portion  36   a  may be provided without the latch lever  36 . 
     The locking plate  35  is forced by a spring (not shown) in an engagement direction or in a clockwise direction in  FIGS. 4-8  to engage with a half-latching pawl  33   a  or a full-latching pawl  33   b  of the latch  33  by the spring owing to turning of the latch with closing of the tailgate. 
     As shown in  FIG. 5 , when the latch  33  turns in the half-latched position, the locking plate  35  engages on the half-latching pawl  33   a  to prevent the latch  33  from turning from the half-latched position to the open position thereby keeping the tailgate closed imcompletely. When the latch  33  turns in the full-latched position, the locking plate  35  engages on the full-latching pawl  33   b  in  FIG. 6  to hold the latch  33  in the full-latched position holding the tailgate in the full-closed position. The locking plate  35  turns against the force of the spring to the releasing position shown by an imaginary line in  FIG. 6  to move away from the half-latching pawl  33   a  or full-latching pawl  33   b  to allow the latch  33  to disengage from the striker  2  enabling the tailgate to open. 
       FIGS. 9-11  are front views of the closing portion  4  during normal operation and  FIGS. 12 and 13  are front views thereof during abnormal operation. The closing portion  4  comprises a motor  42  fixed on the upper part of the base plate  41  fixed to the rear part of the latch housing  31 ; a sector gear  45  as driving member pivoted on a pivot  43  in front of the base plate  41  to mesh with a pinion gear  44  which reduces the speed of the rotation of the motor  42 ; a closing lever  46  pivoted on the pivot  43  to rotate independently from the sector gear  45 ; a spring  50  that enables the closing lever  46  to return to an original position described later; an opening lever  49  pivoted on a pivot  48  on the front surface of the base plate  41 ; and an original position detecting sensor  47  detecting the original position of the sector gear  45  described later. 
     The sector gear  45  comprises a plurality of teeth  45   a  meshing with the pinion gear  44 ; a projection  45   b  that protrudes forwards horizontally; and an original position detecting portion  45   c , and normally held in the original position in  FIGS. 2 and 9 . 
     With closing of the tailgate, when the half-latched position of the latch  33  is detected by a half-latch detecting sensor (not shown), the motor  42  is controlled in a normal rotation, by which the sector gear  45  turns from the original position in a closing direction or in a clockwise direction in  FIGS. 2 and 9 . When the full-latched position of the latch  33  is detected by a full-latch detecting sensor (not shown), the motor is controlled in a reverse direction thereby allowing the sector gear  45  to turn reversely toward the original position. The original position detecting portion  45   c  gets in touch with the original position detecting sensor  47  to detect the original position of the sector gear  45  to enable reverse rotation control of the motor  42  to stop thereby allowing the sector gear  45  to stop at the original position. 
     When operation of a handle (not shown) for opening the tailgate is detected, the motor  42  is controlled reversely. As shown in  FIG. 11 , the sector gear  45  rotates from the original position in a releasing direction opposite to the closing direction, and the motor  42  is controlled reversely to turn toward the original position. The original position detecting portion  45   c  contacts the original position detecting sensor  47  to detect the original position of the sector gear  45  thereby stopping reverse control of the motor  42 , so that the sector gear  45  stops at the original position. 
     The closing lever  46  has a contacted portion  46   a  which can contact the projection  45   b  with rotation of the sector gear  45  in the closing direction; and a cylindrical pressing portion  46   b  which can contact the engagement portion  36   a  if the latch  33  and the latch lever  36  are in the half-latched position. With rotation of the sector gear  45  in the closing direction, the pressing portion  46   b  moves from the original position in  FIG. 9  outside the track of the engagement portion  36   a  in the closing direction or clockwise direction in  FIG. 9  to enable the pressing portion  46   b  to contact the left-side part of the engagement portion  36   a  thereby moving the latch  33  from the half-latched position to the full-latched position. When the latch  33  is moved by the closing lever  46  from the half-latched position to the full-latched position in the normal operation, the closing lever  46  moves to the closing position in  FIG. 10  where the pressing portion  46   b  contacts the left-side part of the engagement portion  36   a.    
     If malfunction occurs as described later, the pressing portion  46   b  of the closing lever  46  contacts right-side part of the engagement portion  36   a  to move to an exceeding position in  FIG. 13  beyond the closed position. When the closing lever  46  is in the original position, a stopper portion  46   c  at the lower part of the closing lever  46  contacts the base plate  41  thereby preventing the closing lever  46  from turning in an opposite direction to the closing direction. 
     One end of the spring  50  engages with the stationary base plate  41  or latch housing  31  by which the closing lever  46  is supported, and the other end of the spring  50  engages with an engagement portion  46   d  of the closing lever  46  to apply force to the closing lever in an anticlockwise direction to return to the original position. 
     The positional relationship between the pressing portion  46   b  of the closing lever  46  and the engagement portion  36   a  of the latch lever  36  will be described with respect to  FIG. 4 . 
     When the closing lever  46  is in the original position, the pressing portion  46   b  goes out of a moving track X of the engagement portion  36   a  when the latch lever  36  moves from the open position to the full-latched position and vice versa, and the closing lever  46  moves in a closing direction to enable the pressing portion  46   b  to invade the track X. When the latch  33  is in the open position, the engagement portion  36   a  goes out of a moving track Z of the pressing portion  46   b , while the latch  33  moves into the half-latched position to allow the engagement portion  36   a  to come into the moving track Z. 
     The opening lever  49  is kept in a waiting position in  FIGS. 2 ,  9 ,  10  and  12  by the spring  51  wound on the pivot  48 . With rotation of the sector gear  45  in a releasing direction, the opening lever  49  turns from the waiting position to the releasing position in  FIG. 11  against the force of the spring  51  to turn the locking plate  35  to the releasing position which allows the latch  33  to disengage from the striker  2  to enable the tailgate to open. 
     Then, normal operation will be described. When the tailgate closes, the latch  33  and latch lever  36  turn from the open position in  FIG. 4  to the half-latched position in  FIG. 5  enabling the engagement portion  36   a  to come into the moving track Z of the pressing portion  46   b  and enabling the locking plate  35  to engage with the half-latching pawl  33 .a to prevent the latch  33  from turning along the opening direction. When the half-latched position of the latch  33  is detected by a half-latch detecting sensor (not shown), the sector gear  45  is rotated from the original position in  FIG. 9  in the closing direction by the motor  42  to allow the engaging portion  45   b  to press the engaged portion  46   a  of the closing lever  46  enabling the closing lever  46  to move in the closing direction against the force of the spring  50 . 
     With the movement of the closing lever  46  in the closing direction, the pressing portion  46   b  contacts the engagement portion  36   a  in the closed position in  FIG. 10 , so that the latch  33  and latch lever  36  turns from the half-latched position to the full-latched position in  FIG. 6 . 
     The latch  33  turns to the full-latched position to allow the locking plate  35  to contact the full-latching pawl  33   b  to hold the latch  33  in the full-latched position. Then, with the full-latch detecting sensor (not shown), the full-latched position of the latch  33  is detected, so that the motor  42  is reversely controlled. With the driving force, the sector gear  45  reversely turns to return to the original position. Following the operation, the closing lever  46  returns to the original position by the spring  50 . 
     In a full-closed position of the tailgate or when the latch  33  is in a full-latched position and when the locking plate  35  engages on the full-latching pawl  33   b  in  FIG. 6 , the door handle of the tailgate is operated and the motor  42  is reversely controlled. By the driving force, as shown in  FIG. 11 , the sector gear  45  turns in a releasing position from the original position to allow the engaging portion  45   b  to contact the opening lever  49  to turn the opening lever  49  to the releasing position in  FIG. 11 . On the basis of the rotation of the opening lever  49 , the locking plate  35  turns to the releasing position to disengage from the full-latching pawl  33   b  and to make the latch  33  freely turn in the opening direction thereby allowing the latch  33  to disengage from the striker  2  to enable the tailgate to open. 
     For example, owing to malfunction or wrong detection of the half-latch detecting sensor when the tailgate is closed, the sector gear  45  and the closing lever  46  are moved from the original position to the closing position by the motor  42 . Thereafter, with respect to  FIGS. 7 ,  8 ,  12  and  13 , it will be described how to operate the latch  33  and the latch lever  36  when they turns from the open position to the full-latched position. 
     In this case, as shown in  FIG. 7 , before the latch  33  and the latch lever  36  moves to the half-latched position, the pressing portion  46   b  of the closing lever  46  comes into the track Z of the engagement portion  36 a. So when the tailgate is closed in this state, the engagement portion  36   a  contact the left side of the pressing portion  46   b  with rotation of the latch  33  from the open position to the full-latched position to allow the latch  33  to contact the full-latching pawl  33   b  in  FIGS. 8 and 13  resulting in malfunction not to allow the closing lever  46  to return to the original position. The sector gear in the closed position is shown by an imaginary line in  FIG. 13 . 
     However, even if malfunction in which the closing lever  46  is prevented from returning to the original position occurs, the closing lever  46  is movable to an exceeding position in  FIG. 13  beyond the closed position against the force of the spring  50  with turning of the latch  33  thereby allowing the sector gear  45  to return to the original position shown by the solid line in  FIG. 13  without damaging to each part owing to the reverse rotation control of the motor  42 . 
     Furthermore, in the malfunction, when the tailgate is completely closed, reverse rotation control of the motor  42  by the operating handle allows the sector gear  45  to turn from the original position in the releasing direction thereby opening the tailgate. When the tailgate opens, the latch  33  turns from the full-latched position to the open position to allow the engagement portion  36   a  to go out of the track Z of the pressing portion  46   b  enabling the closing lever  46  to move to the original position by the spring  50 . So both of the sector gear  45  and the closing lever  46  returns to the original position or normal condition. 
       FIGS. 14 and 15  show another embodiment of the present invention. In this embodiment, instead of the spring  50  for forcing the closing lever  46  to the original position, a spring  60  is provided. One end of the spring  60  engages with the sector gear  45 , while the other end engages with the closing lever  46 . The closing lever  46  urges the sector gear  45  in an anticlockwise direction. The other structure is the same as those of the foregoing embodiment and the same numerals are assigned to the same members of the foregoing embodiment. Its description is omitted. 
     Normally, a closing lever  46  is kept to contact a stopper  45   d  of a sector gear  45  by a spring  60  to rotate together with the sector gear  45 . Thus, when the sector gear  45  turns in a closing direction, the closing lever  46  and spring  60  operates with the sector gear  45 , so that force by the spring  60  does not act as resistance during normal operation. 
     As mentioned above, if wrong detection of a half-latched sensor allows the engagement portion  36   a  to contact a pressing portion  46   b  to prevent the closing lever  46  from returning to the original position, the sector gear  45  turns reversely against the force of the spring  60  from a position shown by an imaginary line to the original position shown by a solid line while the closing lever  46  is prevented from returning to the original position in  FIG. 15 . And the latch  33  turns to an open position to allow a engagement portion  36   a to go out of the track Z of a pressing portion  46   b  enabling the closing lever  46  to return to the original position by the spring  60 . 
     The foregoing merely relate to embodiments of the present invention. Various modifications and changes may be made without departing from the scope of claims. For example, 
     (i) the driving member may be a rack that moves linearly by the motor  42  instead of the sector gear  45 , and/or 
     (ii) the present invention may be applied to a swinging side door or a slide door.