Patent Publication Number: US-6901623-B2

Title: Wiper pivot

Description:
This is a Continuation Application of application Ser. No. 09/775,621 filed Feb. 5, 2001 now U.S. Pat. No. 6,718,592; the disclosure of which is incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a wiper pivot for rotatably supporting a pivot shaft connected with a wiper arm in order to wipe the windshield of the motor vehicle by using the wiper motor. 
   2. Description of the Prior Art 
   As the wiper pivot for supporting rotatably the pivot shaft connected with the wiper arm, a wiper pivot to be used in the wiper linkage  50  shown in  FIG. 8  has been known. A pair of wiper pivots  51  and  52  is used in the wiper linkage  50  shown in  FIG. 8 , and the first and second wiper pivots  51  and  52  are secured at the both ends of a pipe frame  55 , respectively. The first and second wiper pivots  51  and  52  are respectively formed with a first and a second pivot holder  51   a  and  52   a  for rotatably supporting a first and a second pivot shaft  53  and  54  respectively and body-fixing portions  51   b  and  52   b . The first and second wiper pivots  51  and  52  are fixed by screwing the respective body-fixing portions  51   b  and  52   b  on an inner panel disposed on the under side of a cowl top panel (not shown). The top ends of the first and second pivot shafts  53  and  54  are disposed protrudingly from the cowl top panel, and secured respectively with wiper arms fitted with wiper blades. The first and second pivot shafts  53  and  54  are connected to base ends of a first and a second pivot arm  56  and  57  which form a part of linkage  62  at the respective base ends thereof, and a first link connecting rod  58  which forms another part of the linkage  62  is connected between the respective free ends of the first and second pivot arms  56  and  57 . Furthermore, one end of a second link connecting rod  59  which forms another part of the linkage  62  is connected to a position near to the free ends of the first pivot arm  56 , and another end of the second link connecting rod  59  is connected to the free end of a motor arm  60  which forms the other part of the linkage  62 . The motor arm  60  is secured with an output shaft  61   a  of a wiper motor  61  at the base end thereof. 
   In the aforementioned conventional wiper pivot, there is a problem in that an object (body) receives a remarkable impact from the protruding pivot shafts  53  and  54  at the time of collision of the object against the pivot shafts  53  and  54 . 
   SUMMARY OF THE INVENTION 
   It is, therefore, a purpose of the present invention to provide a wiper pivot, which is possible to prevent the object (body) from the large impulsive force even if the pivot shaft collides with the object from the outside. 
   The above-mentioned purpose can be achieved by providing a wiper pivot according to this invention, which is characterized by comprising a pivot shaft provided with a base end connected to a wiper motor through a wiper linkage, and a top end to be disposed protrudingly from a body panel of the vehicle and connected to a wiper arm fitted with a wiper blade; and a pivot holder made of resin and provided with a shaft-holding portion having a shaft hole for rotatably supporting the pivot shaft and a body-fixing portion to be secured on the body panel of the vehicle, formed in one body together with the shaft-holding portion through a connecting portion; wherein the connecting portion of the pivot holder is provided with a thin-walled destructible portion to be destroyed at the time when impulsive force exceeding a predetermined value is applied on the pivot shaft. 
   In the wiper pivot according to this invention, if an object collides with the pivot shaft disposed protrudingly from the vehicle body panel and large impulsive force exceeding the predetermined value is applied to the pivot shaft, the destructible portion of the pivot holder is destroyed, whereby the shaft holding portion and the body-fixing portion of the pivot holder are separated from each other and the pivot holder is displaced in the direction of the vehicle body panel. Therefore, the large impulsive force can not be applied to the object even if the object collides with the pivot shaft. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view illustrating an embodiment of the wiper pivot according to this invention; 
       FIG. 2  is a side view of the wiper pivot shown in  FIG. 1 ; 
       FIG. 3  is a top view of the wiper pivot shown in  FIG. 2 ; 
       FIG. 4  is a bottom view of the wiper pivot shown in  FIG. 2 ; 
       FIG. 5  is a cross sectional view taken on the lines V—V of  FIG. 3 ; 
       FIG. 6  is a cross sectional view taken on the lines VI—VI of  FIG. 3 ; 
       FIG. 7  is a perspective view illustrating the wiper pivot shown in  FIG. 1  in the state of being mounted on the vehicle body; and 
       FIG. 8  is a bottom view of the wiper linkage used in the conventional wiper pivot. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   An embodiment of the wiper pivot according to this invention will be described below on basis of  FIGS. 1  to  7 . 
   The wiper pivot  1  shown in figures is composed mainly of a pivot shaft  2 , a pivot holder  3  and a destructible portion  4 . 
   The pivot shaft  2  is formed with a pivot arm-fitting portion (not shown) at the base end of a round rod-shaped shaft body  2   a . The shaft body  2   a  of the pivot shaft  2  is formed with a pin-groove  2   c  at a position near to the top end thereof. A wiper arm-fitting portion  2   d  is formed at the top end of the shaft body  2   a  on the upper side of the pin-groove  2   c  of the pivot shaft  2 . 
   The shaft body  2   a  of the pivot shaft  2  is inserted rotatably in a shaft hole  3   b   3  formed in the pivot holder  3 . At the pivot arm-fitting portion formed in the base end of the shaft body  2   a  of the pivot shaft  2  as mentioned above, a pivot arm  5  is secured through a wave washer (not shown) by caulking at a pivot shaft-fixing portion  5   a  thereof. 
   A C-shaped pin (stopper)  6  is fitted in the pin-groove  2   c  of the pivot shaft  2 . The outer diameter of the C-shaped pin  6  is larger than the outer diameter of the shaft body  2   a  of the pivot shaft  2 . A plain washer  7  is disposed between the C-shaped pin  6  and a first projection  3   b   1  of the shaft-holding portion  3   b  of the pivot holder  3 . The inner diameter of the plain washer  7  is slightly larger than the outer diameter of the shaft body  2   a  of the pivot shaft  2  and the outer diameter of the plain washer  7  is larger than the inner diameter of a shaft hole  3   b   3  formed in the pivot holder  3 . The plain washer  7  is in contact with the first projection  3   b   1  of the shaft-holding portion  3   b . The pivot arm  5  is secured at the base end of the shaft body  2   a  of the pivot shaft  2  and the C-shaped pin  6  is attached to the pivot shaft  2  through the plain washer  7  at the position near to the top end of the shaft body  2   a . Accordingly, the pivot shaft  2  is prevented to come out from the shaft hole  3   b   3  formed in the shaft-holding portion  3   b  of the pivot holder  3 . 
   The pivot shaft  2  is formed with a positive screw  2   d   1  and a serration  2   d   2  at the wiper arm-fitting portion  2   d . The wiper arm-fitting portion  2   d  of the pivot shaft  2  is passed through a securing portion  20   a  formed in the base end of a wiper arm  20  shown in  FIG. 7 , whereby the serration  2   d   2  of the pivot shaft  2  is engaged with a serration receiver (not shown) formed at the securing portion  20   a  of the wiper arm  20 . The positive screw  2   d   1  of the pivot shaft  2  is pierced into a hole formed in the securing portion  20   a  and is screwed into a nut (not shown), thereby securing the wiper arm  20  on the wiper arm-fitting portion  2   d  of the pivot shaft  2 . Furthermore, a wiper blade  21  is fitted to the top end of the wiper arm  20  as shown in FIG.  7 . 
   The pivot arm  2  is disposed so that the wiper arm-fitting portion  2   d  of the pivot arm  2  may be protruded from a pivot hole  70   a  formed in a cowl top panel (body panel)  70  shown in FIG.  7 . The wiper arm  20  fitted with the wiper blade  21  is secured to the pivot shaft  2 . Therefore, if large impulsive force is applied to the wiper blade  21  or the wiper arm  20 , the impulsive energy caused by the impulsive force is given to the shaft-holding portion  3   b  of the pivot holder  3  through the pivot shaft  2 , the C-shaped pin  6  and the plain washer  7 . 
   The pivot holder  3  is formed of resin and provided with a holder body  3   a , a connecting portion  3   c , a body-fixing portion  3   d  and a frame-connecting portion  3   e  in addition to the shaft-holding portion  3   b  described above in a united one body. 
   The holder body  3   a  is formed in a rectangular shape and disposed in the substantially center of the pivot holder  3 . The shaft-holding portion  3   b  is formed in the center of the holder body  3   a.    
   The shaft-holding portion  3   b  is formed in a hollow cylindrical shape, and formed with the first projection  3   b   1  protruding on the upper side of the holder body  3   a  and a second projection  3   b   2  protruding on the lower side of the holder body  3   a.    
   The first projection  3   b   1  of the shaft-holding portion  3   b  is in contact with the plain washer  7  and the second projection  3   b   2  of the shaft-holding portion  3   b  is in contact with the wave washer (not shown) as described above. 
   The shaft-holding portion  3   b  is formed with the shaft hole  3   b   3  opened from the first projection  3   b   1  toward the second projection  3   b   2 , and inserted rotatably with the shaft body  2   a  of the pivot shaft  2 . 
   The connecting portion  3   c  is disposed so as to bridge between the holder body  3   a  and the body-fixing portion  3   d  on the right side of the holder body  3   a  shown in FIG.  2 . The connecting portion  3   c  is formed with the destructible portion  4 . The destructible portion  4  is composed of a first thin-walled portion  4   a , a second thin-walled portion  4   b  and a third thin-walled portion  4   c.    
   The first thin-walled portion  4   a  of the destructible portion  4  is disposed in the center of the connecting portion  3   c , and formed in a thin-walled shape on the side of a lower face  3   c   2  of a first hollow  3   c   3  cut out in a rectangular shape toward the lower face  3   c   2  from an upper face  3   c   1  of the connecting portion  3   c . The first thin-walled portion  4   a  has thickness t 2  sufficiently smaller than height t 1  of the connecting portion  3   c  as shown in FIG.  5 . The first thin-walled portion  4   a  and the first hollow  3   c   3  are formed in arcuate shapes on the circumference of a circle with a diameter of “r 1 ” about the same center “a”, which is also the center of the shaft hole  3   b   3  of the shaft-holding portion  3   b  as shown in FIG.  3 . 
   The second thin-walled portion  4   b  of the destructible portion  4  is disposed on one side of the lateral of the connecting portion  3   c , and formed in a thin-walled shape on the side of the upper face  3   c   1  of a second hollow  3   c   4  cut out in a rectangular shape toward the upper face  3   c   1  from the lower face  3   c   2  of the connecting portion  3   c . The second thin-walled portion  4   b  has thickness t 2  equal to the thickness of the first thin-walled portion  4   a  and sufficiently smaller than the height t 1  of the connecting portion  3   c  as shown in FIG.  6 . The second thin-walled portion  4   b  and the second hollow  3   c   4  are formed in arcuate shapes on the circumference of the circle with the diameter of “r1” about the center “a” of the shaft hole  3   b   3  of the shaft-holding portion  3   b . A partition wall  3   c   6  is disposed between the first hollow  3   c   3  and the second hollow  3   c   4 , and the second hollow  3   c   4  has an opening on the opposite side of that of the first hollow  3   c   3 . 
   The third thin-walled portion  4   c  of the destructible portion  4  is disposed on the other side of the lateral of the connecting portion  3   c  so as to form a pair together with the second thin-walled portion  4   b . The third thin-walled portion  4   c  is formed also in a thin-walled shape on the side of the upper face  3   c   1  of a third hollow  3   c   5  cut out in a rectangular shape toward the upper face  3   c   1  from the lower face  3   c   2  of the connecting portion  3   c . The third thin-walled portion  4   c  is sufficiently small as compared with the height t 1  of the connecting portion  3   c  and has thickness t 2  equivalent to the thickness of the first and second thin-walled portions  4   a  and  4   b  as shown in FIG.  6 . The third thin-walled portion  4   c  and the third hollow  3   c   5  are formed in arcuate shapes on the circumference of the circle with the diameter of “r1” about the center “a” of the shaft hole  3   b   3  in the shaft-holding portion  3   b . A partition wall  3   c   7  is disposed between the first hollow  3   c   3  and the third hollow  3   c   5  and the third hollow  3   c   5  is opened on the opposite side of the opening of the first hollow  3   c   3 . 
   The second thin-walled portion  4   b , the first thin-walled portion  4   a  and the third thin-walled portion  4   c  of the destructible portion  4  are disposed continuously in the circumferential direction of the shaft hole  3   b   3  of the shaft-holding portion  3   b  between the shaft-holding portion  3   b  and the body-fixing portion  3   d . Therefore, the connecting portion  3   c  is destroyed by absorbing the striking energy caused by shearing stress, bending stress or torsional stress applied on the shaft-holding portion  3   b  through the plain washer  7  from the C-shaped pin  6  at the time when the large impulsive force is applied on the wiper blade  21  or the wiper arm  20 . Consequently, the shaft-holding portion  3   b  and the holder body  3   a  are separated from the body-fixing portion  3   d . In this time, the striking energy applied to the shaft-holding portion  3   b  is uniformly given against the first, second and third thin-walled portions  4   a ,  4   b  and  4   c , and the striking energy is absorbed infallibly by the destructible portion  4  because the first, second and third thin-walled portions  4   a ,  4   b  and  4   c  are formed in arcuate shapes on the circumference of the circle about the center “a” of the shaft hole  3   b   3  in the shaft-holding portion  3   b.    
   The body-fixing portion  3   d  of the pivot holder  3  is formed continuously from the connecting portion  3   c  on the right side of the connecting portion  3   c  in FIG.  2 . The body-fixing portion  3   d  is fitted with a shock-absorbable damper  8  made of rubber in a damper-fitting portion  3   d   1  formed in a forked shape. 
   A bolt (not shown) is passed through the damper  8  and screwed into the inner panel such as a dash upper panel disposed on the lower side of the cowl top panel, thereby securing the pivot holder  3  on the vehicle body at the body-fixing portion  3   d.    
   The frame-connecting portion  3   e  of the pivot holder  3  is formed continuously from the holder body  3   a  on the left side of the shaft-holding portion  3   b  in FIG.  2 . The frame-connecting portion  3   e  is formed at the end  55   a  of the pipe frame  55  (see  FIG. 8 ) through the outsert moulding together with the holder body  3   a , the shaft-holding portion  3   b , the connecting portion  3   c  and the body-fixing portion  3   d . The end  55   a  of the pipe frame  55  is compressed in a plate-like shape to form a plate portion  55   a   1 , and formed with a round hole  55   a   2  in the plate portion  55   a   1 . The shaft-holding portion  3   b  of the pivot holder  3  is moulded so as to locate the shaft hole  3   b   3  in the hole  55   a   2  as shown in FIG.  5 . 
   A pair of such the wiper pivots  1  are disposed to the both ends of the wiper frame  55  of the wiper linkage  50  as shown similarly in  FIG. 8 , and mounted on the vehicle body by screwing the body-fixing portions  3   d  of the respective wiper pivots  1  on the inner panel of the vehicle body, furthermore the wiper arms  20  and the wiper blades  21  are fitted on the respective pivot shafts  2  protruding from the pivot holes  70   a  of the cowl top panel  70 . 
   In the wiper pivot  1  structured as mentioned above, if the predetermined large impulsive force is applied to the wiper arm  20 , the wiper blade  21  or the pivot shaft  2  by the collision with the object or body, the impulsive force is given to the shaft-holding portion  3   b  through the plain washer  7  from the C-shaped washer  6  of the pivot shaft  2 , whereby the first, second and third thin-walled portions  4   a ,  4   b  and  4   c  of the destructible portion  4  are cut off by the impulsive force and the shaft-holding portion  4   b  and the holder body  3   a  are separated from the body-fixing portion  3   d . Accordingly, the pivot shaft  2  is dislocated from the predetermined position in the pivot holder  3  and displaced in the lower direction of the cowl top panel, the impulsive force is received by the body panel having a plane portion and elasticity as compared with the pivot shaft  2 , and it is possible to reduce the impulsive force applied on the object. 
   As mentioned above, in the wiper pivot according to this invention, the destructible portion of the pivot holder is destroyed in the case where the object collides with the pivot shaft disposed protrudingly on the body panel and large impulsive force exceeding the predetermined value is applied on the pivot shaft, whereby the shaft-holding portion is separated from the body-fixing portion of the pivot holder and it is possible to displace the pivot shaft in the direction of the body panel. Accordingly, an excellent effect can be obtained in that the large impulsive force is not applied on the object even if the object collides with the pivot shaft of the wiper pivot from the outside.