Window lift mechanism

Details Window lift mechanism Window lift mechanism

1998-09-21

2001-04-17

Redman, Jerry (Department: 3634)

Movable or removable closures

With operator for movably mounted closure

Drive within closure housing

C049S358000, C049S362000, C074S089140, C074S089170

Reexamination Certificate

active

06216394

ABSTRACT:

TECHNICAL FIELD
The subject invention generally relates to an apparatus for moving a closure member, such as a window, into an open or closed position.
BACKGROUND ART
All modem automobiles include a window lift assembly for raising and lowering windows in the door of the vehicle. The most common type of window lift assembly incorporates a “scissor mechanism.” As shown in
FIG. 1
, a scissor-type system includes a door
10
, a window
12
vertically moveable within the door
10
, a horizontal support bracket
14
on the window
12
, and a scissor mechanism
16
supported on the door
10
and engaged with a track
17
on the support bracket
14
. A sector rack
18
is supported on the scissor mechanism
16
, and a pinion gear
20
supported on the door
10
is engaged with the sector rack
18
. In vehicles with power windows, a worm gear
22
driven by a motor
24
is engaged with a driven gear
26
which, in turn, is operatively joined to the pinion gear
20
. The motor
24
, worm gear
22
, and driven gear
26
are all mounted to the door
10
of the vehicle. In vehicles without power windows (not shown), the pinion gear is driven by a manual hand-crank.
Unfortunately, the scissor-type mechanism includes many drawbacks such as the large amount of space and numerous parts required. The scissor-type mechanism is also mechanically inefficient, prohibiting the use of light-weight materials and requiring the use of relatively large motors to drive the system. The large motors necessarily require increased space and electrical power and also increase the weight of the system. With the limited space in a scissor-type system it is also necessary, in order to provide the required torque transfer efficiency and acceptable up and down times (3-4 seconds), to have a small diameter pinion gear, typically 0.5 to 0.75 inches, and relatively large driven gear, typically 1.8 to 2.5 inches in diameter, with gear ratios of 9 to 16 and 80 to 90, respectively. This results in excessive worm gear speed in the range of 3000 to 4000 RPM which causes excessive driven gear tooth shock and armature noise. The combination of high torque, typically 80 to 125 inch-pounds at stall, and shock due to high worm speeds mandates that either expensive multiple gears and/or single driven gears with integral shock absorbers be utilized.
In U.S. Pat. No. 4,167,834 to Pickles, a more mechanically efficient vertical rack and pinion window lift system is disclosed. This type of system is represented in
FIGS. 2 and 3
and includes a door
28
, a window
30
vertically moveable within the door
28
, a support bracket
32
on the window
30
, a vertical rack
34
supported on the door
28
, and a pinion gear
36
supported on the support bracket
32
in engagement with the rack
34
. A motor
38
is supported on the support bracket
32
on the same side of the window
30
as the rack
34
and pinion gear
36
and drives the pinion gear
36
through a worm gear/driven gear transmission (not shown) engaged with the pinion gear
36
. The pinion gear
36
is continually meshed with the rack
34
to drive the window
30
up and down. Obvious advantages of this system are the mechanical efficiency, fewer parts and, hence, reduced weight, and reduced motor size. The system is also more simple to install than the scissor-type system.
The Pickles window lift assembly, while theoretically plausible, does not function adequately due to the complex method and arrangement used to adapt the support bracket
32
, motor
38
, worm gear, and driven gear to the window
30
. As discussed in United States Patent No.
4
,
967
,
510
to Torii et al., in window lift systems of the type shown in
FIGS. 2 and 3
(such as the Pickles system) a larger torque than necessary is required to drive the system due to the angular moment set up by the weight of motor
38
and related structure acting upon moment arm L
1
. In addition, more space than necessary is required due to the “superimposed sequential” stacking of components in the thickness direction of the door resulting in an overall width W
1
.
The system disclosed in the patent to Torii et al. improved substantially over Pickles in its functional adaptability. The Torii system is represented in FIG.
4
and includes a window
40
, a support bracket
42
on the window
40
, a motor
44
, a pinion gear
46
, and a rack
48
. To eliminate the angular moment on the window
40
caused by the weight of the motor
44
, the Torii system positioned the motor
44
such that the center of gravity of the motor
44
was substantially aligned with the plane of movement of the window
40
. However, as shown in
FIG. 4
, this arrangement prevents the rack
48
from being positioned as close as possible to the window
40
, resulting in an increased angular moment on the window
40
caused by the torque generated at the rack/pinion gear interface acting upon a larger than necessary moment arm L
2
(due to the larger than necessary overall width W
2
). The angular moment can cause the window to “pull in” in the direction shown by the arrow labeled P. Further, although not shown in
FIG. 4
, the Torii system includes a support bracket for supporting the window
40
and motor
44
. Similar to the Pickles system, the support bracket is “sequentially stacked” with respect to the motor, unnecessarily increasing the overall width of the system.
In co-pending U.S. patent application Ser. No. 08/762,447, now U.S. Pat. No. 6,073,395 filed Dec. 9, 1996 by Fenelon, the inventor of the present application, the restrictive and rigid systems presented by Pickles and Torii et al. were vastly improved upon by incorporating controlled flexibility into the rack system, hence providing for smooth operation as the window is raised and lowered. The system also reduced the number of components by “modularizing” the support bracket and minimizing the torque placed on the window by altering the “stacking arrangement” of the motor plus transmission, support bracket, and rack plus driven gear. This improved arrangement is shown in
FIGS. 5 and 6
where reference numeral
52
is the window,
64
is the motor attached to the inside of support bracket
61
, and
62
is the pinion gear intermeshed with rack
56
. Note that W
3
is the total width of the stacked arrangement and L
3
is the moment which produces torque on window
52
. Similar to Pickles and Torii et al., Fenelon's improved arrangement “sequentially stacks” the components, unnecessarily increasing the overall width of the system.
Therefore, it is desirable to provide a window lift system which includes the benefits of a rack and pinion system, allows for smooth operation as the window is raised and lowered, and minimizes the torque placed on the window. Additionally, it is desirable to minimize the space occupied by the various components in all dimensions and particularly in the thickness direction of the door, and further to minimize the total number of components and hence the overall weight of the system.
SUMMARY OF THE INVENTION AND ADVANTAGES
In one embodiment of the present invention, a closure assembly is provided including a closure member, a support bracket joined to the closure member, a first pinion gear supported by the support bracket, and a first rack operatively engaged with the first pinion gear. A driven gear is supported for rotation by the support bracket and is operatively joined with the pinion gear. A motor is supported by the support bracket and includes an output shaft engaged with the driven gear. The support bracket fulfills a dual function by simultaneously acting as a transmission housing. The motor defines a profile in a width-wise direction, and the support bracket is positioned substantially within the width-wise profile of the motor. In this manner, the space occupied by the motor and support bracket can be minimized while further reducing the number of individual components required.
In another embodiment of the present invention, a closure assembly is provided including a closure member, a support bracket joined to the closure member, a f

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