Supports – Stand – Adjustable vertically
Reexamination Certificate
2002-05-31
2003-12-23
Braun, Leslie A. (Department: 3632)
Supports
Stand
Adjustable vertically
C248S422000, C248S396000, C297S344150
Reexamination Certificate
active
06666423
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of the Invention
The present invention relates to a ratchet-type lever mechanism for seat lifter (or seat height adjuster), which is operable by rotation of an operation lever to actuate the seat lifter for the height adjustment of seat. Particularly, the invention is directed to a ratchet-type lever drive mechanism having a ratchet gear system provided about the shaft of a brake unit operatively connected with a seat lifter, wherein an operating lever can be rotated to cause the brake unit shaft to rotate in a desired direction corresponding to the direction in which the seat lifer is raised or lowered.
2. Description of Prior Art
A seat height adjuster or what is known as a seat lifter is incorporated in automotive seat to enable an occupant on the seat to selectively adjust the height of seat according to his or her physique and seating posture. In the seat lifter, typically known is a linkage-type seat lifter having forward and rearward links which are interlockingly movable and pivotally coupled with the forward and rearward portions of the seat, respectively, so that the seat may be raised and lowered via those two links. This seat lifter includes plural transmission gears (reduction gears and the like), a brake-unit, and a drive mechanism provided with a lever or handle, wherein the drive mechanism is operatively connected through the transmission gears and bake unit to the forward and rearward links. As known in the art, the brake unit provides a braking action on the drive mechanism to normally lock the links to a given position. Conventionally, the drive mechanism is provided with a dial-type rotary handle which is directly connected with a shaft of the brake unit. However, since a great load is applied to the seat lifter and the brake unit, it is highly possible that a user will use quite more force than normally required to rotate such dial-type handle with his and her one hand. In view of such problem, for instance, a ratchet-type lever drive mechanism is disclosed in the Japanese Laid-Open Patent Publication No. 2000-255295. According thereto, instead of the dial handle, an operating lever is used, which is connected with two ratchet pawl gears, and two ratchet wheel gears are fixed to the output shaft of the brake unit, such that, by vertical rotation of the operating lever, one of the two pawl gears may be selectively meshed with a corresponding one of the two ratchet wheel gears, thereby causing upward and downward motions of the seat lifter to raise and lower a seat to a desired level.
FIG. 1
a typical example of seat lifter (SL) provided with a conventional ratchet-type lever mechanism (
110
) similar to the foregoing mechanism. As is known, the seat lifter (SL), although only its one lateral side portion is shown, basically comprises a pair of forward link (
80
) and backward link (
81
), and a sector gear (
84
) pivotally connected via a connecting link (
83
) with the backward link (
81
). The forward link (
80
), facing to a side (F) forwardly of the seat lifter and seat cushion frame (F), is pivotally connected at its upper end with the seat cushion frame (F) via a pin (
80
a
) and likewise connected at its lower end with a base frame or an upper rail of slide rail device (designated by (
90
)) via a pin (
80
b
). The backward link (
81
), facing to a side (B) backwardly of the seat lifter (SL) and seat cushion frame (F), is at its midway part pivoted to the seat cushion frame (F) via pin (
81
a
), while being pivotally connected at its lower end with the base frame or upper rail (at
90
) via a pin (
81
b
). The sector gear (
84
) is rotatably connected to the seat cushion frame (F). In the shown mode, an inwardly toothed gear portion (
84
a
) is formed in the sector gear (
84
). Sector gear (
84
) is rotatably fixed to the seat cushion frame (F). On the other hand, the ratchet-type lever mechanism (
110
) includes a pair of first and second ratchet wheel gears (
12
u
)(
12
d
) fixed to the shaft of brake unit (
16
), and a bifurcated ratchet gear (
300
) connected with an operating lever (
214
). Though not shown, the first ratchet wheel gear (
12
u
) has a known one-way clutch built therein, by which the gear (
12
u
) itself is only permitted to rotate together with the shaft (
16
a
) of brake unit (
16
) in clockwise direction to cause upward motion of the seat lifer (SL) to raise the seat cushion frame (F), while being free to rotate about the brake unit shaft (
16
a
) in anticlockwise direction. On the other hand, the second ratchet wheel gear (
12
d
) has another one-way clutch therein for only permitting the gear (
12
d
) itself together with the brake unit shaft (
16
a
) to rotate in anticlockwise direction to cause downward motion of the seat lifter (SL) to lower the seat cushion frame (F), while being free to rotate about the brake unit shaft (
16
a
) in clockwise direction. The bifurcated ratchet gear element (
300
) is formed with a first pawl gear (
300
a
) and a second pawl gear (
300
b
), wherein the first pawl gear (
300
a
) is bent and offset from the second pawl gear (
300
b
). As s shown, the bifurcated ratchet gear (
300
) is securely supported on a bearing shaft (
228
) connected with the operating lever (
214
) and normally positioned at a point where both first and second pawl gears (
300
a
)(
300
b
) are out of mesh with the respective first and second ratchet wheel gears (
12
u
)(
12
d
).
As found in the foregoing conventional combination of ratchet-type lever mechanism (
110
) and seat lifter (SL), it has been customary that upward rotation of the operating lever (
214
) results in likewise upward movement of seat cushion frame (F) or a seat via the seat lifter (SL) for the sake of easiness in operation. Otherwise stated, in the seat lifter (SL), the backward link (
81
), the sector gear (
84
) and the connecting link (
83
) establish a particular transmission mechanism through which a normal upward rotation of operating lever (
214
) by a user or seat occupant is transmitted to both two links (
80
) (
81
), thereby transforming the rotation into upward motion of the seat lifter (SL) itself to raise a vehicle seat (not shown). Specifically, when a user rotates the lever (
214
) upwardly as indicated by the one-dot-chain arrow, the bifurcated ratchet gear (
300
) is rotated anticlockwise, bringing the first pawl gear toothed portion (
226
u
) to mesh with the first ratchet gear wheel (
12
u
). Then, as indicated by the arrows, both first ratchet gear wheel (
12
u
) and shaft (
16
a
) of brake unit (
16
) are rotated clockwise to cause simultaneous clockwise rotation of pinion gear (
7
) meshed with the inwardly toothed portion (
84
a
) of sector gear (
84
), which in turn causes the likewise clock rotation of the sector gear (
84
).
Such clockwise rotation causes upward rotation of both two links (
80
) to raise the seat cushion frame (F) or not-shown seat. Therefore, this particular transmission mechanism of seat lifter (SL) naturally requires clockwise rotation as “normal direction of rotation” for upward motion to raise a vehicle seat, as indicated by the arrow (N) in particular.
In contrast to such normal-rotation-type lever mechanism (
110
), there has been known a reverse-rotation-type seat lifter having a particular transmission mechanism requiring anticlockwise rotation as a “reverse direction of rotation” to raise the vehicle seat. This is shown in
FIG. 2
, by way of one example, as designated by (SL′), which is basically identical to the afore-said seat lifter (SL), only excepting a sector gear arrangement (
85
) including an outwardly toothed gear (
85
a
) and an integral backward link portion (
85
c
). In other words, the transmission mechanism of this seat lifter (SL′) is formed by such combination of outwardly-toothed gear teeth (
85
a
) and backward link portion (
85
c
). Specifically, according to this reverse-rotation-type seat lifter (SL′), the sector gear arrangement (
85
) is pivotally secured by a pin (
85
b
) to the seat cushion frame (F), while being a
Braun Leslie A.
Browdy and Neimark , P.L.L.C.
Le Tan
Tachi-S Co. Ltd.
LandOfFree
Ratchet-type lever mechanism for seat lifter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ratchet-type lever mechanism for seat lifter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ratchet-type lever mechanism for seat lifter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3176583