U.S. patent application number 11/086725 was filed with the patent office on 2005-07-28 for window lift mechanism.
Invention is credited to Fenelon, Paul J..
Application Number | 20050160675 11/086725 |
Document ID | / |
Family ID | 32989296 |
Filed Date | 2005-07-28 |
United States Patent
Application |
20050160675 |
Kind Code |
A1 |
Fenelon, Paul J. |
July 28, 2005 |
Window lift mechanism
Abstract
A dual rack and pinion system is provided for a window lift
mechanism. The window lift mechanism includes improved window
brackets for simple mounting to a window. A modular frame design is
provided to improve assembly of the window lift mechanism into the
door of a vehicle. An improved assembly method is provided for the
dual rack and pinion system. The system is also provided with a
smart motor and incorporates resilient shock absorbers in the dual
rack and pinion gear train to allow more time for the smart motor
to detect and react to an obstruction in the window.
Inventors: |
Fenelon, Paul J.;
(Nashville, TN) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Family ID: |
32989296 |
Appl. No.: |
11/086725 |
Filed: |
March 22, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11086725 |
Mar 22, 2005 |
|
|
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10400820 |
Mar 27, 2003 |
|
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Current U.S.
Class: |
49/375 |
Current CPC
Class: |
E05Y 2201/49 20130101;
E05F 11/423 20130101; E05F 15/41 20150115; E05Y 2900/55 20130101;
E05F 15/40 20150115; E05F 11/385 20130101; E05F 15/689 20150115;
E05Y 2600/46 20130101; E05Y 2900/538 20130101; E05Y 2201/434
20130101 |
Class at
Publication: |
049/375 |
International
Class: |
E05F 015/08 |
Claims
What is claimed is:
1. A closure assembly comprising: a closure member; a window
bracket coupled to said closure member, said window bracket
including a channel for receiving said closure member therein; and
a wedge mechanism received in said channel for securing said
closure member in said channel.
2. The closure assembly of claim 1, wherein said wedge mechanism is
spring biased into said channel.
3. The closure assembly of claim 1, wherein said channel includes
at least one inwardly angled sidewall.
4. The closure assembly of claim 1, wherein said wedge mechanism
includes an elastomeric wedge member pivotally supported by an
over-center toggle spring mechanism pivotally mounted to said
window bracket.
5. The closure assembly of claim 1, further comprising a support
member coupled to said window bracket and adapted to be driven for
the raising and lowering of said closure member; and an interface
between said window bracket and said support member permitting
axial and pivotal movement of said closure member with respect to
said support member.
6. The closure assembly of claim 5, wherein said interface includes
a head portion slidably and rotatably received in a guide
portion.
7. The closure assembly of claim 6, wherein said head portion is
semi-cylindrical and said guide portion is semi-cylindrical.
8. A method for assembling a window lift mechanism, comprising the
steps of: mounting a motor housing assembly to a main bracket, said
motor housing assembly including a motor drivingly connected to a
worm and worm gear, said worm gear including a shaft rotatably
connected to said worm gear and extending through said main
bracket; mounting a first pinion gear onto said shaft and mounting
a second pinion gear in meshing engagement with said first pinion
gear; placing a dual rack system in alignment with said pinion
gears; and applying power to the motor to drive said pinion gears
to engage said pinion gears with said dual rack system.
9. The method of claim 8, wherein said step of applying power to
the motor further includes driving the first and second pinion
gears to move the main bracket and motor to a predetermined
position for convenient door installation.
10. The method of claim 8, wherein said step of placing a dual rack
system in alignment with said pinion gears includes placing the
dual rack assembly in a guide system of said main bracket.
11. A dual rack assembly, comprising: a base frame structure
adapted to be mounted to a vehicle door; and a pair of rack members
each including a plurality of gear teeth extending along said rack
members, said rack members being snap fit to said base frame
structure.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 10/400,820, filed on Mar. 27, 2003, the disclosure of
which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to an apparatus for
moving a window into an open or closed position. In particular, the
present invention relates to a mechanism for use with an automobile
window, wherein the mechanism utilizes an improved dual rack and
pinion assembly and method of manufacturing.
BACKGROUND OF THE INVENTION
[0003] Modern automobiles typically include a window lift assembly
for raising and lowering windows in the door of the vehicle. A
common type of window lift assembly incorporates a "scissor
mechanism" or a drum and cable mechanism. A scissor-type system
utilizes a series of linkages in a scissor configuration such that
as the bottom linkages move apart, the top linkages do as well,
resulting in a scissor-like motion. The window is fastened to a
bracket connected to a linkage. A motor and gearset drives the
scissor mechanism in power operated window mechanisms.
[0004] The scissor-type and drum and cable mechanisms are typically
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 or drum and cable 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 worm 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 worm 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 worm gears with
integral shock absorbers be utilized.
[0005] Further, the scissor-type mechanism does not take into
account the manufacturing deviations in the door, specifically with
the window frame and mounting points, and deviations in the
manufacture of the scissor-type mechanism. Deviations in the door
and scissor-type mechanism result in larger than necessary forces
being applied to the window when it cycles up and down. The larger
force on the window causes undesirable noise in the passenger
cabin.
[0006] Accordingly, a need exists for a window lift mechanism with
increased efficiency that would allow for a reduction in the motor
size and hence the mass of the system, and a support structure for
the window that permits the window to find the path of least
resistance when it cycles up and down.
SUMMARY OF THE INVENTION
[0007] The present invention provides a window lift mechanism that
utilizes a dual rack and pinion drive mechanism that includes a
motorized input from a worm shaft that drives a worm gear drivingly
connected to one of the pinions of the dual rack and pinion system.
A motor with the worm driveshaft and the pinions are supported by a
base which traverses the dual rack structure when the dual pinions
are driven. According to one aspect of the present invention, the
window lift mechanism has two support structures each including a
window bracket coupled to the window. The window brackets each
include a channel for receiving the window therein. A pair of metal
plates are disposed on opposite sides of the window bracket and
include a clamping mechanism engaging each of the pair of metal
plates for drawing the metal plates toward one another.
[0008] According to an alternative embodiment of the present
invention, the window brackets are each provided with a wedge
mechanism received in the channel for securing the closure member
in the channel.
[0009] According to another aspect of the present invention, a
method for assembling a window lift mechanism is provided including
mounting a motor to a base, the motor including a worm drive shaft
and worm gear meshingly engaged therewith. The method includes
loading pinion gears into the base by placing the pinion gear onto
a drive shaft connected to the worm gear and mounting the second
pinion gear in the base. A dual rack assembly is then placed in
alignment with the pinion gears and power is applied to the motor
to drive the pinion gears to engage the pinion gears with the
rack.
[0010] According to still another aspect of the present invention,
the dual rack assembly is made as a modular unit including a base
or frame structure which is adapted to be mounted to the door of
the vehicle. The pair of rack members each including a plurality of
gear teeth extending along the rack members are formed either as a
molded unitary piece with the base structure, or are snap fit or
otherwise fastened to the base structure for defining the modular
unit.
[0011] According to yet another aspect of the present invention,
the dual rack and pinion assembly is provided with a smart motor
capable of detecting unusual forces applied to the window while
being closed and capable of either shutting off or reversing drive
of the motor. The system is further provided with one or more
resilient shock absorbers operably engaged between the worm gear
and pinion gears in order to allow the drive motor to have more
time to react to unusual forces applied to the window.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention will become more fully understood from
the detailed description and the accompanying drawings,
wherein:
[0013] FIG. 1 is a schematic view of a window lift mechanism for an
automobile door according to the principles of the present
invention;
[0014] FIG. 2 is a partially cut-away view of the window lift
mechanism according to the principles of the present invention;
[0015] FIG. 3 is a perspective view of a support structure
including a window clamp mechanism on the window bracket for the
window lift mechanism according to the principles of the present
invention;
[0016] FIG. 4 is an end view of the support structure of FIG. 3
illustrating a cross-sectional view of the window clamp mechanism
on the window bracket;
[0017] FIG. 5 is a perspective view of an alternative support
structure including a window clamp mechanism on the window bracket
for the window lift mechanism according to the principles of the
present invention;
[0018] FIG. 6 is an end view of the support structure of FIG. 5
illustrating a cross-sectional view of the window clamp mechanism
on the window bracket;
[0019] FIG. 7 is a plan view of the main bracket of the dual rack
and pinion system according to the principles of the present
invention;
[0020] FIG. 8 is a front plan view of the main bracket having a
motor assembly mounted thereto according to the principles of the
present invention;
[0021] FIG. 9 illustrates the main bracket being mounted to the
dual rack system by drivingly rotating the pinion gears
therewith;
[0022] FIG. 10 is a front view of the dual rack and pinion system
fully assembled according to the principles of the present
invention;
[0023] FIG. 11 is a perspective view of a modular dual rack and
pinion system for mounting to a door of a vehicle;
[0024] FIG. 12 is a detailed view of the modular dual rack and
pinion system according to the principles of the present
invention;
[0025] FIG. 13 illustrates a snap-fit engagement between a dual
rack system to the frame of the modular assembly;
[0026] FIG. 14 shows the dual rack system being mounted to the
frame of the modular dual rack and pinion system utilizing threaded
fasteners;
[0027] FIG. 15A is a schematic view of a dual rack and pinion
system utilizing multiple resilient shock absorbers according to
the principles of the present invention;
[0028] FIG. 15B is a partial perspective view of a dual rack and
pinion system utilizing multiple resilient shock absorbers
according to FIG. 15B;
[0029] FIG. 16 is an exploded perspective view of a slave pinion
gear as illustrated in FIG. 15;
[0030] FIG. 17 is a cross-sectional view of the slave pinion gear
of FIG. 16 in an assembled condition;
[0031] FIG. 18 is a plan view of one of the gear segments of the
slave pinion gear of FIG. 16;
[0032] FIG. 19 is a graph illustrating the delayed force obtained
in a smart motor window lift system utilizing multiple shock
absorber according to the principles of the present invention;
and
[0033] FIG. 20 is a graph providing a comparison of force-time
distance plots as a window traverses up for a convention window
lift mechanism versus a dual rack and pinion system with built-in
shock absorbers according to the principles of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] The following description of the preferred embodiment(s) is
merely exemplary in nature and is in no way intended to limit the
invention, its application, or uses.
[0035] Referring generally to FIG. 1, a vehicle door 10 is shown
schematically including a window lift mechanism 12. A window 14 is
supported by the window lift mechanism 12 and is located within the
automobile door 10. The window lift mechanism 12 includes a support
structure 16 and a drive system 18. The drive system 18 is
supported by the support structure 16 and serves to drive the
support structure 16 relative to a pair of racks 20, 22 which are
securely mounted to the door 10.
[0036] The support structure 16 includes a main bracket 24.
According to a first embodiment, a pair of guide brackets 26 (best
shown in FIGS. 3 and 4) are mounted to the main bracket 24 by a
fastener 28 and a nut 30. The guide brackets 26 include a body
portion 32 including an elongated vertical slot 34 for receiving
the fastener 28. A pair of opposing stop flanges 36 extend from
opposite sides of the body portion 32. An elongated
semi-cylindrical guide portion 38 is disposed on an upper neck
portion 40 of the guide bracket 26. The support structure 16
further includes a pair of window brackets 42 which are slidably
engaged with the guide brackets 26.
[0037] The window brackets 42 have a window channel 44 for receipt
of the window 14 and a guide channel 46 having a semi-cylindrical
inner surface for receiving the semi-cylindrical guide portion 38
of the guide bracket 26, as best shown in FIG. 4a. The guide
channel 46 has an opening end portion 48 having a diameter greater
than a width of the upper neck portion 40 of the guide bracket 26
so as to allow angular movement (.varies.) of the window bracket 42
relative to the guide bracket 26, as illustrated in FIG. 4. In FIG.
4, the window bracket 42 is shown tilted in a first forward
position and is capable of being moved to a rearward tilted
position, as illustrated by the angle.varies.. The window bracket
42 is able to pivot angularly by a predetermined angular amount
.varies. (up to approximately 25.degree., preferably at least
20.degree.), as well as sliding axially relative thereto in order
to accommodate for variances in the door, support structure, and
drive system. The interface between the opening 48 and upper neck
portion 40, therefore provides the support structure 16 with two
degrees of freedom with regard to the axial and rotational
adjustment achieved by the guide bracket 26 and window bracket 42.
By enabling the window bracket 42 to move with two degrees of
freedom relative to the guide bracket 26, the window 14 is allowed
to find the path of least resistance during opening and closing. In
particular, the two degrees of freedom aids in overcoming unwanted
imperfections in the door 10, window 14, support structure 16, and
drive system 18. The movement of the window bracket 42 relative to
the guide bracket 26 reduces the force placed on the drive system
18 and window 14, as well as reducing the noise generated by the
window 14 and drive system 18.
[0038] As shown in FIG. 3, the window bracket 42 is mounted to the
window by a pair of generally V-shaped metal plates 50A, 50B which
are sandwiched on opposite sides of the window bracket 42. The
window brackets 42 are provided with recessed channels 52 on
opposing faces thereof for receiving the metal plates 50 therein.
As best shown in FIG. 4, a threaded fastener 54 extends through an
aperture 56 in the first metal plate 50A and through apertures 58
and 60 provided in the window bracket 42. The fastener 54 is
threadedly engaged with an internally threaded aperture 62 provided
in a second metal plate 50B. By tightening the threaded fastener
54, metal plates 50A, 50B are drawn inward against the side
surfaces of the window bracket 42 causing the inner surface of the
channel 44 to tightly engage the window 14. The inner sidewalls 64
of the channel 44 are provided with protruding engagement faces 66
at an upper end thereof for engaging the window 14. The recessed
surfaces 52 provided on opposite faces of the window bracket 42
provide limit stops for the V-shaped metal plates 50A, 50B which
act as spring members for applying a clamping force to the window
bracket 42.
[0039] With reference with FIGS. 5 and 6, an alternative window
bracket 70 is provided including a window channel 72 for receipt of
the window 14 and a guide channel 74 having a semi-cylindrical
inner surface for receiving the semi-cylindrical guide portion 38
of the guide bracket 26, as best shown in FIG. 5. The guide channel
74 has an opening end portion 76 having a diameter greater than a
width of the upper neck portion 40 of the guide bracket 26 so as to
allow angular movement of the window bracket 70 relative to the
guide bracket 26, as illustrated in FIG. 6. The channel 72 is
provided with a pair of opposing faces 76, 78. The face 78 is
angled slightly relative to the face 76. A window 14 is inserted
into the channel 72 and is disposed against the face 76 of the
channel. A wedge member 80 is inserted in the channel 72 between
the window 14 and angled face 78. The wedge member 80 is preferably
made of an elastomeric material. A clamping device 82 is provided
for applying force to the wedge member 80. The clamping device 82
includes an over-center toggle spring 84 pivotally mounted to the
window bracket 70 via apertures 86. The over-center toggle spring
84 includes a pair of spring arms 90 disposed at opposite ends of a
cross-bar 92. The spring arms 90 include two end tabs 88 which are
received in the apertures 86. The spring arms 90 each include a
spiral loop portion 94 which acts as a spring. The wedge member 80
is provided with an elongated channel 96 which receives a cross-bar
portion 98 of a clamp wire 100 which includes a pair of opposite
arms 102 which extend from the cross-bar portion 98, and each
terminate in a hook portion 104 which engage the loop portions 94
of the toggle spring member 84.
[0040] During assembly, the window 14 is inserted in the channel 72
and the wedge member 80 is inserted next to the window 14 and
sidewall 78 of the channel 72. The cross-bar 92 of toggle spring
member 84 is then pulled downward from the position shown in FIG. 5
to the position shown in FIG. 6 until the cross-bar portion 92 of
the toggle spring member 84 engages the laterally extending fingers
106 extending from the base of the window bracket 70. In this
position, the toggle spring member 84 applies a spring force to the
clamping wire 100 that in turn applies a clamping force to the
wedge 80 which is biased tightly into the channel 72 for applying a
force against window 14. Thus, in this manner, the window bracket
70 is easily mounted to the window 14 for securing the window 14 to
the main 24.
[0041] Referring to FIG. 2, the main bracket 24 interacts with the
racks 20, 22. The first rack 20 includes a row of teeth 110 which
faces a row of teeth 112 on the second rack 22. Teeth 110 and 112
are in engagement with drive system 18 for raising and lowering the
window 14. As shown in FIG. 1, guide members 114 are provided on
the main bracket 24, adjacent to the first and second racks 20 and
22. Guide members 114 keep the first and second racks 20 and 22 in
engagement with the drive system 18. Guide members 114 are
generally plastic guide channels integrally formed with the main
bracket 24.
[0042] With reference to FIGS. 1 and 2, a general description of
the construction and operation of the dual rack and pinion window
lift mechanism 12 will now be described. First, the main bracket
24, which is generally shown in FIGS. 1 and 2, is shown in a more
preferred arrangement in FIGS. 7-10. In particular, as illustrated
in FIG. 7, on a first face 116 of the main bracket 24, a pair of
recessed channels 118, 120 are provided as well as recessed
portions 122, 124 adapted to receive pinion gears 126, 128 of the
drive system, as best illustrated in FIGS. 1 and 9. A motor housing
assembly 130 is shown mounted to a second surface 132 of the main
bracket 24 in FIG. 8. The motor housing assembly 130 includes a
motor 134 connected to a housing 136. The motor 134 is provided
with a drive shaft 138 (best illustrated in FIG. 2) having a worm
140 in meshing engagement with a worm gear 142. The worm gear 142
is supported on an axle 144 supported by the housing 136. The axle
144 connected to the worm gear 142 extends through an aperture 146
provided in the main bracket 24, as best illustrated in FIG. 7.
During assembly, the motor housing assembly 130 is mounted to the
main bracket 24 and is secured in place by threaded fasteners 148
(one of which is shown). After the motor housing assembly 130 is
mounted to the main bracket 24, a drive pinion gear 126 is inserted
in the recess portion 124 of the main bracket 24 and engaged with
the drive spindle 144 of the worm gear 142. In addition, a slave
pinion gear 128 is inserted in the recess portion 122 of the main
bracket 24 and is in meshing engagement with the drive pinion gear
126. At this time, the motor 134 is connected to an electrical
power source and a dual rack system 150 is brought into alignment
with the channels 118, 120 of the main bracket 24 and inserted part
way until the dual rack system 152 engages the pinion gears 126,
128. At this time, the motor 134 is driven in order to engage the
pinion gears 126, 128 with the dual rack system 150, as best
illustrated in FIG. 10. The motor is then driven to move the main
bracket 24 and motor 134 to a predetermined position for convenient
door installation. The dual rack system 150 includes a pair of
elongated parallel racks 20, 22 each including a plurality of teeth
extending therealong. A lattice-type cross brace structure 151
extends between, and is integrally molded as a unitary piece with,
the pair of racks 20, 22. All of the components, except the motor,
are made from high precision engineered thermoplastics.
[0043] As illustrated in FIGS. 11-14, the dual rack and pinion
window lift mechanism 12 is preferably mounted to a frame 160 that
allows the frame 160 and window lift mechanism 12 to be mounted
into a vehicle door as a modular unit 162, as best illustrated in
FIG. 11. As shown in FIG. 12, the dual rack system 150 is
preferably molded as an integral piece with the frame 160. The
frame 160 is provided with mounting holes 164 which facilitate
mounting the modular unit 152 to the vehicle door 10. The door 10
is provided with corresponding mounting holes 165 which are in
alignment with mounting holes 164 on the frame 160. In addition,
the frame 160 is provided with additional mounting holes 166, as
illustrated in FIG. 12, to allow mounting of additional components
168 (shown in phantom) and that can include air bags, speakers, or
other door components.
[0044] As an alternative to molding the dual rack system 150
integrally with the frame 160, the dual rack system 150 can also be
provided with snap-fit engagement for connection to the frame 160
by including snap insert members 168 as illustrated in the
cross-section of FIG. 13, or fasteners 170 such as threaded bolts,
screws, or rivets can also be utilized for connecting the dual rack
system 150 to the frame 160 as illustrated in FIG. 14. The modular
unit 162 facilitates easy installation of the window lift mechanism
into the door of the vehicle. Once the modular unit 162 is
installed in the door, the window 14 can be inserted in the
channels provided in the window brackets 42/70, and the window
brackets 42/70 are then clamped to the window 14, as described
above.
[0045] A recent development in power window regulators are referred
to as smart regulators, i.e., to have the capability of going up
and down fast by touching the switch once. Due to automotive
regulations, it is mandatory that on the way up, that from 4 inches
to 0.1 inch from the top, the window must be capable of stopping
and reversing prior to generating a force in excess of 100 Newtons.
To achieve this, manufacturers have utilized sophisticated
electronics and memory chips so that the window knows where it is
at all times based on past or previous experience. In this way, if
the window senses an object in its path, it will know that it is
abnormal and hence, reverse. Essentially, detection methods are put
in place by using memory chips employed within a controller 174, as
illustrated in FIG. 2, so that deviation from a "learned reference"
is known. These "learned references" are typically based on motor
speed, motor current, or rate of change in speed (acceleration).
Electronics used in combination with the memory chips utilize
expensive componentry, such as a current shunt, multiple pull
magnets, hall sensors, and commutator pulse detection sensors. The
cost and performance of the smart units are dependent upon the time
available for the motor to "detect and react" to where it was prior
to generating forces greater than 100 Newtons. While various smart
motor systems have been successfully adapted to arm and sector and
cable units, a number of problems exist. Specifically, the design
of these systems are such that varying degrees of slack are
inherent, and this slack varies continuously and unpredictably over
the life of those products. The mechanical inefficiency of those
systems requires that larger motors than necessary, typically
motors capable of achieving 90 inch pounds plus are utilized which
leaves a greater amount of excess force to cause damage to objects
that may obstruct the window in the event of malfunctioning of the
smart system. Dual rack and pinion regulators are precision
manufactured from injection molded engineered thermoplastic, which
means that the degree of slack inherent in the system is
repeatable, controllable, and based on experience gained, is
constant over time. In order to increase the response time
available to the smart motor system prior to reaching the 100
Newton force limitation, the dual rack and pinion system of the
present invention is provided with a worm gear 142, drive pinion
gear 126, and slave pinion gear 128 which are modified to act as
shock absorbers. The shock absorbers slow down the pinch process so
that a simplified smart motor may have more time to "detect and
react" to any interruption in window upward movement.
[0046] With reference to FIGS. 15-18, a dual rack and pinion system
utilizing multiple shock absorbers will now be described. As
illustrated in FIG. 15A, a worm 140 is in driving engagement with a
worm gear 142. The worm gear 142 is provided in driving engagement
with a drive spindle 144 via resilient spring members 180 which can
be in the form of elastomeric shock absorber 182 as illustrated in
FIG. 16. The drive spindle 144 is drivingly connected to the drive
pinion gear 126 via a second resilient spring member 184. As
described previously, the drive pinion gear 126 is in driving
engagement with the rack 22 of the dual rack assembly 150.
Furthermore, the drive pinion gear 126 engages a first gear portion
128A of the slave pinion gear 128. The slave pinion gear 128
includes a second pinion gear portion 128B which is connected to
the first pinion gear portion 128A via a resilient spring member
186. The second pinion gear portion 128B of the slave pinion gear
128 engages the rack 20 of the dual rack assembly 150. FIG. 15B
illustrates a perspective view of the dual rack and pinion system
shown in FIG. 15A. As shown in FIG. 15B, the racks 20, 22 are
spaced apart relative to one another.
[0047] FIG. 16 illustrates an exploded perspective view of the
construction of the slave pinion gear 128, as shown in FIG. 15A,
15B. In particular, the first gear portion 128A of the slave pinion
gear 128 includes a plurality of axially extending fingers 190
which are received in radially outwardly extending recesses 192 of
the resilient shock absorber 182. Furthermore, the second gear
portion 128B of the slave pinion gear 128 includes a hollow body
portion provided with radially inwardly extending fingers 194 which
are received in radially inwardly extending recesses 196 of the
elastomeric shock absorber 182. With this construction, the shock
absorber 182 is capable of absorbing shock forces that are
delivered between the first gear portion 128A and second gear
portion 128B of the slave pinion gear 128.
[0048] With regard to the construction of the worm gear 142 and
drive pinion gear 126, it is noted that each of these gears is
constructed similar to second gear portion 128B of the slave pinion
gear 128. In particular, each of these gears include radially
inwardly extending fingers, such as fingers 194, which engage an
elastomeric shock absorber such as shock absorber 182 illustrated
in FIG. 16. The drive shaft 144 is provided at each end thereof
with radially outwardly extending fingers, similar to fingers 190.
It should be noted that other constructions using torsion springs
or other elastomeric members having different configurations may
also be utilized with the present invention. Similar systems
utilizing stress dissipation technology are disclosed in commonly
assigned U.S. Pat. Nos. 5,307,705, 5,452,622, and 5,943,913 for
providing shock absorbance in a gear system.
[0049] When a shock absorber system is utilized in combination with
a smart motor system and the upward moving window is obstructed and
generates an impulse determined by force multiplied by time (Fxt)
the shock absorbers increase the time factor, hence reducing the
applied force at any point in time. With reference to FIG. 19, the
influence of shock absorbent on the force versus distance/time plot
as a window traverses up, is illustrated graphically for a dual
rack and pinion system utilizing different numbers of shock
absorbers (0-3). As illustrated in the drawings, the use of each
additional shock absorber increases the time that is available
prior to reaching a stall force for the motor. This increase in
time, due to the use of multiple shock absorbers, increases the
ability of a smart motor to prevent the window from reaching a
predetermined maximum force level. Accordingly, the componentry of
the smart motor can be reduced in complexity and cost due to the
additional time allotted for reaction to the detected force. An
additional benefit of the use of multiple shock absorbers is that
they reduce the amount of vibration transferred from components of
the gear train to the next and, therefore, reduce the noise
generated by the dual rack and pinion system.
[0050] FIG. 20 graphically illustrates a typical arm and sector
and/or cable system as compared to the dual rack and pinion system
with built-in shock absorbers. It is noteworthy that existing arm
and sector and cable units also have shock absorbers built into the
worm gear of the system. As illustrated in FIG. 20, typical arm and
sector and/or cable systems require higher amounts of force which
are required to overcome gravity and guide friction as illustrated
by point A on the line representing the conventional system. In
comparison, for the dual rack and pinion system with built-in shock
absorbers, the amount of force required to overcome the window
weight and guide channel resistance is significantly less as
illustrated by point B. In addition, because of the increased
efficiency of the dual rack and pinion system, the system can be
provided with a smaller motor which reduces the amount of torque
applied by the system and therefore, reduces the amount of
potential torque that can be applied to an obstruction in the
window. A typical dual rack and pinion system utilizes a motor
which uses approximately 65 inch pounds of torque as compared to an
arm and sector or cable system which utilizes a motor capable of
producing upward of 90 inch pounds of torque. Finally, the amount
of time from hitting an obstruction until a stall torque is
obtained for a conventional system is approximately 60
milliseconds, whereas for the dual rack and pinion system this time
is approximately 140 to 200 milliseconds when utilizing built-in
shock absorbers. The more time provided for detection of an
obstruction, allows the use of a less complex and hence, more
economic smart regulator system.
[0051] The description of the invention is merely exemplary in
nature and, thus, variations that do not depart from the gist of
the invention are intended to be within the scope of the invention.
Such variations are not to be regarded as a departure from the
spirit and scope of the invention.
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