Abstract:
Ends of each supporting pin are projected to both sides of each link plate. Each supporting shaft is fixed by welding to each link plate at a position near one end side of the plate. A pipe-like connecting shaft is axis-aligned to and fitted on an end portion of the supporting pin which projects inward from each link plate, so as to be supported between link plates. An end portion of the supporting pin which projects outward from each link plate is passed through a side frame section and fixedly riveted over. Further, each link plate is fixed by welding to both ends of the connecting shaft, and a link base frame is assembled between side frame sections.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a height adjusting device for a vehicle seat, which can adjust a height of the entire vehicle seat. 
   BACKGROUND OF THE INVENTION 
   As a height adjusting device for a vehicle seat, there is known a height adjusting device for a vehicle seat, which includes two pairs of spaced apart forward and rearward linkage members bridged between side frame sections of a seat cushion frame of the vehicle seat and two pairs of spaced apart brackets of upper rail members of a track mechanism for allowing the vehicle seat to be slid forward and rearward in an interior of a vehicle, a first connecting shaft interconnecting the rearward linkage members and supported to the side frame sections of the seat cushion frame, a second connecting shaft interconnecting the forward linkage members and supported to the side frame sections, and an operating knob attached to one of the side frame sections of the seat cushion frame, and which is adapted to cause a height of the vehicle seat to be moved vertically by operating the operating knob (Japanese Patent Application Laid-Open No. 2001-138780). 
   The height adjusting device further includes a pinion gear arranged within the seat cushion frame, a sector gear pivotally supported through a supporting pin to the side frame section of the seat cushion frame and meshed with the pinion gear, and a linkage rod coupled at one end thereof to a portion of the sector gear which is offset from the supporting pin of the sector gear, and coupled at the other end thereof to one of the rearward linkage members. 
   In the height adjusting device, the first connecting shaft for interconnection of the rearward linkage members is formed of a pipe and the rearward linkage members are supported to the first connecting shaft which is bridged between the spaced apart side frame sections of the seat cushion frame. 
   However, in the conventional height adjusting device, it will take a lot of labor to cause the rearward linkage members to be held in position to the first connecting shaft, and cause the first connecting shaft to be supported to the side frame sections of the seat cushion frame. In addition, the first connecting shaft is not supported to the side frame sections with reliability. 
   SUMMARY OF THE INVENTION 
   It is therefore an object of the present invention to provide a height adjusting device for adjusting a height of a vehicle seat, in which a pair of rearward linkage members can be easily held in position to a connecting shaft and the connecting shaft can be easily supported to a pair of spaced apart side frame sections of a seat cushion frame with reliability. 
   In accordance with the present invention, there is provided a height adjusting device for adjusting a height of a vehicle seat. The vehicle seat includes a seat cushion frame supported through first and second pairs of spaced apart brackets. The seat cushion frame has first and second spaced apart side frame sections. The height adjusting device comprises two pairs of forward and rearward linkage members, the forward linkage members being bridged between first portions of the side frame sections and the first pair of the spaced apart brackets, the rearward linkage members being bridged between second portions of the side frame sections and the second pair of the spaced apart brackets, a connecting shaft rotatably supported to coupling the side frame sections, the rearward linkage members being supported by the connecting shaft, and an operating knob attached to the first side frame section for causing the forward and rearward linkage members to be actuated, thereby causing the vehicle seat to be vertically moved. The height adjusting device further includes supporting pins having first end portions and second end portions, the first end portions of the supporting pins being penetrated through the rearward linkage members, welded to the rearward linkage members and fitted in both ends of the connecting shaft, the second end portions of the supporting pins being penetrated through the spaced apart side frame sections and riveted over. The rearward linkage members are welded to the connecting shaft. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic side view of a height adjusting device for adjusting a height of a vehicle seat, according to the present invention, in which the vehicle seat is in a lowered condition; 
       FIG. 2  is a schematic exploded perspective view illustrating a pinion gear and a sector gear which are components for the height adjusting device shown in  FIG. 1 ; 
       FIG. 3  is a schematic sectional view illustrating a combination of a connecting shaft and a supporting pin which are components for the height adjusting device shown in  FIG. 1 ; 
       FIG. 4  is a schematic exploded perspective view illustrating the connecting shaft and the supporting pin which are shown in  FIG. 3 ; and 
       FIG. 5  is a schematic side view of the height adjusting device of  FIG. 1 , in which the vehicle seat is in a lifted-up condition. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Now, a height adjusting device for a vehicle seat, according to the present invention, will be discussed hereinafter with reference to the accompanying drawings. Referring to  FIG. 1 , a vehicle seat to which the height adjusting device according to the present invention is applied is constructed so as to be slidable forward and rearward through a track mechanism S in an interior of a vehicle. The track mechanism S comprises a pair of lower rail members R spaced apart from each other and mounted on a vehicle floor in parallel with each other (only one lower rail member R is shown in  FIG. 1 ), and a pair of upper rail members A, each of which is slidably supported to a corresponding lower rail member R (only one upper rail member A is shown in  FIG. 1 ). 
   The vehicle seat includes a seat cushion frame F. A seat back (not shown) is pivotally supported to the seat cushion frame F through recliner means (not shown). The seat cushion frame F comprises a pair of spaced apart side frame sections  2  (only one side frame section  2  is shown in  FIG. 1 ), and a pan frame section  20  arranged between forward portions of the spaced apart side frame sections  2  and attached to the forward portions of the side frame sections  2 . A first pipe-shaped connecting shaft  6  is arranged between rearward portions of the spaced apart side frame sections  2  and connected to the rearward portions of the spaced apart side frame sections  2 . The side frame sections  2  are formed so as to extend upwardly at the rearward portions thereof in which holes  2   b  (only one hole  2   b  is shown in  FIG. 1 ) are formed. Ends of a supporting shaft (not shown) for the recliner means are to be inserted in the holes  2   b . The seat back includes a pair of spaced apart side frame sections. The spaced apart side frame sections of the seat back are supported to the supporting shaft for the recliner means. Thus, the seat back is pivotally supported to the seat cushion frame F so as to be pivotable forward and rearward relative to the seat cushion. 
   Each of the upper rail members A of the track mechanism S includes a pair of forward and rearward brackets  1   a ,  1   b  rising up from the upper rail member A. The height adjusting device includes two pairs of forward first and rearward linkage members  3 ,  4 . Each of the forward linkage members  3  is arranged between corresponding one of the side frame sections  2  of the seat cushion frame F and the forward bracket  1   a  of corresponding one of the upper rail members A. Similarly, each of the rearward linkage members  4  is arranged between corresponding one of the side frame sections  2  of the seat cushion F and the rearward bracket  1   b  of corresponding one of the upper rail members A. The forward linkage members  3  are coupled through a second connecting shaft  5  to each other. Similarly, the rearward linkage members  4  are coupled through the first connecting shaft  6  to each other. 
   The forward linkage members  3  are formed into substantially linear shapes and supported at one ends thereof to the side frame sections  2  by supporting pins  30  and at the other ends thereof to the forward brackets  1   a  of the upper rail members A by supporting pins  31 . Moreover, the forward linkage members  3  are connected at substantially middle regions thereof to each other through the second connecting shaft  5 . The side frame sections  2  of the seat cushion frame F are formed in lower surfaces thereof with notches  2   a  which allow the second connecting shaft  5  to be moved synchronously with pivotal movement of the forward linkage members  3 . Each of the notches  2   a  is formed into a substantially circular arc-shape. 
   Each of the rearward linkage members  4  is formed into a substantially L-shape. The rearward linkage members  4  are supported at substantially middle portions thereof to the side frame sections  2  by supporting pins  40  that project from both ends of the first connecting shaft  6 . One ends of the rearward linkage members  4  are connected to the rearward brackets  1   b  of the upper rail members A by supporting pins  41 . 
   The height adjusting device for the vehicle seat further includes an operating knob  7  having a rotating shaft  7   a  and mounted on an outer surface of one of the side frame sections  2  with the rotating shaft  7   a  penetrating through the side frame section  2  and projecting into the seat cushion frame F, a pinion gear  8  arranged within an inside of the seat cushion frame F and mounted on the rotating shaft  7   a  of the operating knob  7  that is projected in the seat cushion frame F through the side frame section  2 , a sector gear  9  rotatably supported to the side frame section  2  by a supporting pin  9   a  and meshed with the pinion gear  8 , and a linkage rod  10  arranged between the sector gear  9  and one of the rearward linkage members  4  that is arranged on the side of the side frame  2  to which the operating knob  7  is mounted. 
   In the illustrated embodiment, as the operating knob  7 , an operating knob that is of a dial-type is employed. Referring to  FIG. 2 , the operating knob  7  includes a body supporting the rotating shaft  7   a  and a mounting section  7   b  of a plate shape, and is arranged on the outer surface of the side frame section  2  with the mounting section  7   b  being attached onto the outer surface of the side frame section  2  and with the rotating shaft  7   a  being penetrated through the side frame section  2 . The operating knob body is constructed so as to be rotatable relative to the mounting section  7   b.    
   The sector gear  9  is rotatably supported at a base portion thereof to the side frame section  2  by the supporting pin  9   a  and coupled at a portion thereof that is offset from the supporting pin  9   a , to one end of the linkage rod  10  by a supporting pin  9   b . As shown in  FIG. 1 , the other end of the linkage rod  10  is coupled to an upper end of the one of the rearward linkage members  4  by a supporting pin  11 . 
   Referring now to  FIG. 3 , inner end portions of the supporting pins  40  (only one supporting pin  40  is shown in  FIG. 3 ) for the first connecting shaft  6  are inserted through the rearward linkage members  4  in the ends of the first connecting shaft  6 , and the first connecting shaft  6  is welded to the rearward linkage members  4 . Outer end portions of the supporting pins  40  are penetrated through the side frame sections  2  so as be rotatable relative to the side frame sections  2 , so that the supporting pins  40  act as supports for pivotal movement of the rearward linkage members  4 . 
   Referring to  FIG. 4 , each of the supporting pins  40  (only one supporting pin  40  is shown in  FIG. 4 ) includes a circumferential flange portion  40   a  provided between the inner end portion  40   b  extending inwardly from the circumferential flange portion  40   a  and inserted in corresponding one of the ends of the first connecting shaft  6  through corresponding one of the rearward linkage members  4 , and the outer end portion extending outwardly from the circumferential flange portion  40   a  and penetrating through corresponding one of the side frame sections  2 . The outer end portion of the supporting pin  40  comprises a large diameter region  40   c  and a relatively small diameter region  40   d . The small diameter region  40   d  of the supporting pin  40  is to be riveted over after the outer end portion of the supporting pin  40  is penetrated through the side frame section  2 . 
   In order to cause the outer end portion of the supporting pin  40  to be securely held in to the corresponding side frame section  2 , a first washer  42 , a bearing collar  43 , a bushing  44 , and a second washer  45  are employed. The bearing collar  43  comprises a boss portion  43   a  and a pair of wings portions  43   b  laterally extending in directions opposite to each other from the boss portion  43   a . The bearing collar  43  is mounted on the inner surface of the side frame section  2  with the boss portion  43   a  being fitted in a hole of the side frame section  2  and with the wing portions  43   b  being welded to the side frame section  2 . 
   Now, a procedure for coupling an end of the first connecting shaft  6  to the corresponding rearward linkage member  4  and the corresponding side frame section  2  through the supporting pin  40  will be discussed in greater detail hereinafter. First of all, the inner end portion  40   b  of the supporting pin  40  is penetrated through the rearward linkage member  4  in such a manner that the circumferential flange portion  40   a  of the supporting pin  40  is applied onto an outer surface of the rearward linkage member  4 . Then, the circumferential flange portion  40   a  of the supporting pin  40  is welded onto the outer surface of the rearward linkage member  4  by projection welding (see  FIG. 3 ). 
   The end of the first connecting shaft  6  is then fitted over the inner end portion  40   b  of the supporting pin  40  welded to the rearward linkage member  4 . The first washer  42  and the boss portion  43   a  of the bearing collar  43  are fitted over the outer end portion of the supporting pin  40  which projects outward from the end of the first connecting shaft  6 . Then, the outer end portion of the supporting pin  40  is inserted through a hole of the side frame section  2 . 
   The bushing  44  is then fitted over the outer end portion of the supporting pin  40  that has been projected outward of the side frame  2 , and fitted into the boss portion  43   a  of the bearing collar  43  through the hole of the side frame section  2 . The second washer  45  is then mounted on the outer end portion of the supporting pin  40 . Thereafter, the small diameter portion  40   d  of the supporting pin  40  is riveted over the second washer  45  as a riveted portion  40   e  (see  FIG. 3 ). Moreover, the first connecting shaft  6  is welded to the rearward linkage member  4 . The other end of the first connecting shaft  6  is connected to the other of the side frame sections  2  in the same manner as the one end of the first connecting shaft  6  is connected to the one of the side frame sections  2 . Thus, the first connecting shaft  6  is rotatable relative to the side frame sections  2 . 
   As described above, first of all, the inner end portions  40   b  of the supporting pins  40  are penetrated through the rearward linkage members  4  and then welded to the rearward linkage members  4 . The ends of the first connecting shaft  6  are then fitted over the inner end portions  40   b  of the supporting pins  40  welded to the rearward linkage members  4 . In this way, a combination that comprises the first connecting shaft  6  and the rearward linkage members  4  attached in position to the first connecting shaft  6  is assembled. Thereafter, the outer end portions of the supporting pins are connected to the side frame sections  2  and riveted over. Therefore, the rearward linkage members  4  can be easily supported in position to the first connecting shaft  6  and the second connecting shaft  5  can be easily and reliably supported to the side frame sections  2 . 
   As shown in  FIG. 2 , a gear cover  12  for covering the pinion gear  8  and the sector gear  9  is provided. The gear cover  12  comprises a base portion  12   a , a substantially cylindrical-shaped portion  12   b  projecting laterally from the base portion  12   a , and a top portion  12   c  lying on the substantially cylindrical-shaped portion  12   b  and extending laterally from the substantially cylindrical-shaped portion  12   b . The top portion  12   c  is formed with a first hole  12   d  and a second hole  12   e  in which the rotating shaft  7   a  of the operating knob  7  and the supporting pin  9   a  of the sector gear  9  are respectively inserted. 
   The gear cover  12  is secured on an inner surface of the side frame section  2  with the cylindrical-shaped portion  12   b  and top portion  12   c  covering the pinion gear  8  and the sector gear  9 , with the base portion  12   a  being mounted on the inner surface of the side frame section  2 , and with the first and second holes  12   d ,  12   e  of the gear cover  12  receiving the rotating shaft  7   a  of the operating knob  7  and the supporting pin  9   a  of the sector gear  9 , respectively. Thus, the pinion gear  8  and the sector gear  9  are arranged between the side frame section  2  and the gear cover  12  so as not to be exposed. In addition, the rotating shaft  7   a  of the operating knob  7  and the supporting shaft  9   a  of the sector gear  9  are supported by both the side frame section  2  and the gear cover  12  at their opposite ends. 
   In the height adjusting device constructed as discussed above, in a condition where the vehicle seat is lowered as shown in  FIG. 1 , the linkage rod  10  is thrust rearward by the sector gear  9  and the first and rearward linkage members  3 ,  4  are collapsed rearward. 
   In this condition, when the body of the operating knob  7  is rotated in a predetermined direction, the pinion gear  8  is simultaneously rotated. Synchronously with the rotation of the pinion gear  8 , the sector gear  9  is rotated about the supporting pin  9   a  in a counterclockwise direction in.  FIG. 1 , whereby the linkage rod  10  is drawn forward. Simultaneously with the forward movement of the linkage rod  10 , the rearward linkage members  4  are rotated around the supporting pins  41  so as to operatively stand up and the forward linkage members  3  are also rotated around the supporting pins  31  so as to operatively stand up. Thus, the vehicle seat is lifted up as shown in  FIG. 5 . 
   The rearward linkage members  4  are supported to the side frame sections  2  through the supporting pins  40  coupled to the ends of the first connecting shaft  6 , so that the first and rearward linkage members  3 ,  4  can be stably moved during adjusting of the height of the vehicle seat. Moreover, the pinion gear  8  and the sector gear  9  are arranged between the side frame section  2  and the gear cover  12  so as to be covered by the gear cover  12 , so that any foreign materials can be prevented from being caught between the pinion gear  8  and the sector gear  9 . In addition, the rotating shaft  7   a  of the operating knob  7  that supports the pinion gear  8 , and the supporting pin  9   a  supporting the sector gear  9  are supported by both the side frame section  2  and the gear cover  12  at their opposite ends, so that the sector gear  9  can be securely prevented from being deflected, namely, producing runout. Therefore, the sector gear  9  can be stably and positively rotated by the pinion gear.