Seat lifter for motor vehicles

• US 5,775,661 A
• Filed: 07/08/1996
• Issued: 07/07/1998
• Est. Priority Date: 07/06/1995
• Status: Expired due to Fees

• Current Assignee: Fuji KIKO Company Limited (Toyota Motor Corporation)
• Original Assignee: Fuji KIKO Company Limited (Toyota Motor Corporation)
• Inventors: Kawai, Eiichi, Matsumoto, Tadashi
• Primary Examiner(s): Cranmer, Laurie K.
• Application Number:
  US08/676,730
• Time in Patent Office: 729 Days
• Field of Search: 248/421, 248/422, 248/157, 248/394, 248/395, 297/313, 297/325, 297/330, 297/344.12
• US Class Current: 248/421
• CPC Class Codes: B60N 2/1615 Parallelogram-like structure
• CPC Class Codes: B60N 2/165 Gear wheel driven mechanism
• CPC Class Codes: B60N 2/1803 with independent front and/or rear adjustment
• CPC Class Codes: B60N 2/181 Rods
• CPC Class Codes: B60N 2/1839 pivoting about an axis located in an intermediate position
• CPC Class Codes: B60N 2/1864 Gear wheel driven mechanism

Abstract

A seat lifter comprises a lifter shaft having a sector gear and rotated by a center gear to vertically move a seat frame with respect to a base frame through a link mechanism. The sector gear is formed with a stopper arm protruding from one side thereof, whereas the base frame is formed with a long arc-shaped hole with which a pointed end of the stopper arm is engaged. The long arc-shaped hole is partly covered by a vertical wall of the second frame.

Claims

1. A seat lifter, comprising:

first and second frames;

a shaft arranged through a hole formed in one of said first and second frames, said shaft serving to vertically move said second frame with respect to said first frame through a link;

means for defining a predetermined hole in said first frame, said defining means being partly covered with said second frame;

a sector gear engaged with said shaft, said sector gear being formed with a stopper arm which protrudes from one side of said sector gear, said stopper arm having an end engaged with said defining means; and

a center gear supported to said one of first and second frames, said center gear being meshed with said sector gear.

2. A seat lifter as claimed in claim 1, wherein said shaft is formed with an enlarged-diameter portion at an end thereof, said sector gear being engaged with said shaft to contact said enlarged-diameter portion.

3. A seat lifter as claimed in claim 2, wherein said enlarged-diameter portion of said shaft is obtained by bulging.

4. A seat lifter as claimed in claim 2, wherein said sector gear and said enlarged-diameter portion are connected by welding.

5. A seat lifter as claimed in claim 1, wherein said defining means include said first frame.

6. A seat lifter as claimed in claim 1, wherein said predetermined hole of said defining means is shaped in a long arc.

7. A seat lifter as claimed in claim 1, wherein said sector gear and said center gear have a tooth portion formed in a special theoretical tooth profile.

8. A seat lifter as claimed in claim 1, wherein said sector gear, said center gear, and said link are always biased by a dead weight of said second frame.

9. A seat lifter as claimed in claim 8, wherein the gear ratio of said center gear to said sector gear is 1 to 8-25.

10. A lifter for a seat comprising:

first and second frames;

a shaft arranged through a hole formed in one of said first and second frames, said shaft serving to vertically move said second frame with respect to said first frame through a link;

a sector gear engaged with said shaft, said sector gear having a tooth portion formed in a special theoretical tooth profile; and

a center gear supported to said one of first and second frames, said center gear having a tooth portion formed in a special theoretical tooth profile, said center gear being meshed with said sector gear,

wherein the special tooth profiles of the center gear and the sector gear eliminate a need for an assist spring,

wherein said sector gear, said center gear, and said link are always biased by a dead weight of said second frame, and

wherein the gear ratio of said center gear to said sector gear is 1 to 8-25.

11. A lifter as claimed in claim 10, wherein said hole is arranged to correspond to a front portion of the seat.

12. A lifter for a seat comprising:

first and second frames;

a shaft arranged through a hole formed in one of the first and second frames, the hole being arranged to correspond to a front portion of the seat, the shaft serving to vertically move the second frame with respect to the first frame through a link;

a sector gear engaged with the shaft, the sector gear having a tooth portion formed in a special theoretical tooth profile; and

a center gear supported to the one frame, the center gear having a tooth portion formed in a special theoretical tooth profile, the center gear being meshed with the sector gear,

wherein the special tooth profiles of the center gear and the sector gear eliminate a need for an assist spring,

wherein the sector gear, the center gear, and the link are always biased by a dead weight of the second frame, and

wherein the gear ratio of the center gear to the sector gear is 1 to 8-25.