U.S. patent application number 11/904589 was filed with the patent office on 2008-03-27 for roll-up window shade with reduced-friction drive.
This patent application is currently assigned to BOS GmbH & Co. KG. Invention is credited to Melf Hansen, Wolfgang Stark.
Application Number | 20080073041 11/904589 |
Document ID | / |
Family ID | 38573408 |
Filed Date | 2008-03-27 |
United States Patent
Application |
20080073041 |
Kind Code |
A1 |
Hansen; Melf ; et
al. |
March 27, 2008 |
Roll-up window shade with reduced-friction drive
Abstract
Two drive gears are provided as an extension of the guide rails
for driving a roll-up window shade for a motor vehicle. The drive
gears are coupled to the winding shaft in a rotationally elastic
manner. The driving is carried out via a geared motor, which acts
either on the gears or on the winding shaft. The positioning of the
drive gears as an extension of the guide rails avoids the guide
tubes used in prior art arrangements. Thus, the friction losses
found in the prior art, which consume up to 80% of the drive force,
are avoided. Furthermore, manufacturing is simplified because the
connection tubes having a complicated shape are not needed.
Inventors: |
Hansen; Melf; (Gondelsheim,
DE) ; Stark; Wolfgang; (Denkendorf, DE) |
Correspondence
Address: |
LEYDIG VOIT & MAYER, LTD
TWO PRUDENTIAL PLAZA, SUITE 4900
180 NORTH STETSON AVENUE
CHICAGO
IL
60601-6731
US
|
Assignee: |
BOS GmbH & Co. KG
Ostfildern
DE
73760
|
Family ID: |
38573408 |
Appl. No.: |
11/904589 |
Filed: |
September 27, 2007 |
Current U.S.
Class: |
160/370.22 |
Current CPC
Class: |
B60R 5/047 20130101;
B60J 1/2058 20130101 |
Class at
Publication: |
160/370.22 |
International
Class: |
B60J 1/20 20060101
B60J001/20 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2006 |
DE |
10 2006 046 069.3 |
Sep 27, 2006 |
DE |
10 2006 046 065.0 |
Sep 27, 2006 |
DE |
10 2006 046 064.2 |
Oct 13, 2006 |
DE |
10 2006 049 065.7 |
Nov 13, 2006 |
DE |
10 2006 053 680.0 |
Claims
1. A roll-up window shade for motor vehicles comprising: a
rotatably supported winding shaft; a shade having a first edge
affixed to the winding shaft; a tension rod connected to a second
edge of the shade spaced away from the winding shaft; two guide
rails each extending on a respective side of the shade when the
shade is an extended position, the two guide rails guide the
tension rod in a positive-locking manner; two push elements each
being conducted in a respective one of the guide rails, each push
element carrying a gear-tooth system that acts on the tension rod;
two drive gears arranged at first and second ends of the winding
shaft, each drive gear being allocated to a respective one of the
push elements, wherein the push elements are operatively arranged
between the drive wheels and the tension rod; an electric drive
motor; and a spring compensating element for compensating for
differences in the length of the shade as it is extended as
compared to the corresponding length of travel of the push elements
in the guide rails.
2. The roll-up window shade according to claim 1, wherein the
tension rod is configured so that its length is selectively
variable.
3. The roll-up window shade according to claim 1, wherein a first
end of the each of the guide rails is arranged in the vicinity of
the winding shaft.
4. The roll-up window shade according to claim 1, wherein the guide
rails extend parallel to one another.
5. The roll-up window shade according to claim 1, wherein each
guide rail contains a guide groove.
6. The roll-up window shade according to claim 5, wherein the guide
groove has a cross sectional configuration including a groove
chamber and a groove slit, a diameter of the groove chamber being
larger than an inside width of the slit so as to define an undercut
guide groove.
7. The roll-up window shade according to claim 6, wherein each push
element is conducted in a buckle-resistant manner in the respective
groove chamber.
8. The roll-up window shade according to claim 1, wherein the gear
tooth system of each push element extends around the push
element.
9. The roll-up window shade according to claim 1, wherein each
drive gear is a front gear.
10. The roll-up window shade according to claim 1, wherein each of
the drive gears is connected to the winding shaft.
11. The roll-up window shade according to claim 1, wherein each of
the drive gears is arranged coaxial relative to a rotational axis
of the winding shaft.
12. The roll-up window shade according to claim 1, wherein the two
drive gears are seated on a connection shaft which is conducted
through the winding shaft.
13. The roll-up window shade according to claim 1, wherein the two
drive gears are seated on a connection shaft which runs parallel to
the winding shaft.
14. The roll-up window shade according to claim 1, wherein the
electric drive motor is coupled to the winding shaft.
15. The roll-up window shade according to claim 12, wherein the
electric drive motor is coupled to the connection shaft.
16. The roll-up window shade according to claim 13, wherein the
electric drive motor is coupled to the connection shaft.
17. The roll-up window shade according to claim 12, wherein the
spring compensating element is located between the connection shaft
and the winding shaft and the drive gears are connected to the
connection shaft without rotational play.
18. The roll-up window shade according to claim 13, wherein the
spring compensating element is located between the connection shaft
and the winding shaft and the drive gears are connected to the
connection shaft without rotational play.
19. The roll-up window shade according to claim 13, wherein a gear
pair is provided with one of the gear pair being coupled to the
winding shaft and the other of the gear pair being coupled to the
connection shaft.
20. The roll-up window shade according to claim 1, wherein the
spring compensating element comprises a coil spring.
21. The roll-up window shade according to claim 1, wherein the
spring compensating element comprises a spiral spring.
22. The roll-up window shade according to claim 21, wherein the
spiral spring is seated in a recess of one of the drive gears.
23. The roll-up window shade according to claim 13, wherein the
spring compensating element comprises two springs, one of the two
springs being located between one of the drive gears and the
connection shaft.
24. The roll-up window shade according to claim 1, wherein the
spring compensating element comprises two springs, one of the two
springs being located between the winding shaft and a corresponding
one of the drive gears.
25. The roll-up window shade according to claim 1, wherein the
spring compensating element comprises two springs, one of the two
springs being located between the tension rod and one of the push
elements and the other of the two springs being located between the
tension rod and the other push element.
26. The roll-up window shade according to claim 25, wherein the
springs are compression springs.
27. The roll-up window shade according to claim 1, wherein each
push element has an associated engagement mechanism for keeping the
respective push element engaged with its associated drive gear.
28. The roll-up window shade according to claim 1, where a separate
gear housing is provided for each drive gear.
29. The roll-up window shade according to claim 1, wherein each
push element has a corresponding storage tube for receiving an
empty rail of the push element when the shade is in a retracted
position.
30. The roll-up window shade according to claim 29, wherein each
storage tube is made of a flexible material.
Description
FIELD OF THE INVENTION
[0001] This invention relates to roll-up window shades for motor
vehicles.
BACKGROUND OF THE INVENTION
[0002] Electrically driven rear window roll-up shades are known
from the prior art. These prior art roll-up window shades have a
winding shaft that is pivotably supported below the rear shelf and
on which one edge of the shade is affixed. The other edge of the
shade is connected to a tension rod that is guided at its end by
guide rails. The guide rails are arranged next to the lateral edges
of the rear window and extend from the rear shelf or below it to
the vicinity of the upper edge of the window. In order to
pretension the shade, there is generally a spring motor in the
winding shaft or next to it. This motor biases the winding shaft in
the shade wind-up direction.
[0003] The unwinding or unfolding of the shade is carried out with
the aid of linear push elements that run in a buckle resistant
manner in the groove or slot chamber of the guide rails. A common
gear motor is provided next to the winding shaft approximately at
the level of its center. Guide tubes are provided in order to
connect the gear motor to the lower ends of the guide rails. The
guide tubes end at the gear housing of the geared motor. With the
aid of these guide tubes, the push elements are conducted in a
buckle-proof manner between the drive motor and the guide rails, so
that they can carry out the pushing function.
[0004] Since the motor sits relatively close to the winding shaft
because of space considerations, the guide tubes run more or less
parallel to the winding shaft in the vicinity of the geared motor
and must be deflected in the guide rails in a direction
perpendicular to the winding shaft. In turn, for space
considerations, the radius of curvature of the guide tubes next to
the point where they lead into the guide rails is relatively very
narrow.
[0005] Actual practice shows that with such shades, the push
elements in the guide tubes consume the majority of the drive force
produced by the motor. Only a comparatively small fraction of the
drive force is actually needed to extend the shade.
[0006] The guide tubes generally have a relatively complicated,
three-dimensional shape. As a result, their production and their
adaptation to motor vehicle conditions are difficult.
[0007] In addition, the push elements must also be protected in the
section that lies behind the motor relative to the line of sight.
The length of this part of the push element, which projects above
the motor, depends on the distance the shade extends. The push
element projects least when the shade is extended, whereas the
projection is greatest when the shade is completely retracted.
Since the travel is usually greater than half the width of the
winding shaft, the storage tube taking up the excess part must also
be adapted in a complicated three-dimensional manner to the
available space in the motor vehicle. Thus, not only is the
manufacturing of the roll-up window shade cumbersome, it also is
difficult to install in a motor vehicle.
[0008] The problems with known designs have been described in the
context of a rear window roll-up shade. Similar problems are found
with roll-up window shades for sunroofs, which are driven in a
comparable manner. The high friction losses of the push elements in
the guide and storage tubes also create complications with regard
to the design and dimensioning of an electric-based pinch
protection system, which is based on the measurement of the motor
current. Depending on the magnitude of the friction losses, more or
less force may be available at the given interruption current to
catch or pinch body parts.
OBJECTS AND SUMMARY OF THE INVENTION
[0009] In view of the foregoing, a general object of the present
invention is to provide a roll-up window shade for motor vehicles
having a drive with lower friction losses.
[0010] The roll-up window shade of the invention includes a
rotatably supported winding shaft. In the usual manner, one edge of
the shade is affixed to this winding shaft. The other edge of the
shade is connected to a tension rod, the ends of which run in guide
rails. The guide rails extend on both sides of the extended shade
and define the path which the tension rod travels between the
retracted and extended positions of the shade.
[0011] The drive of the tension rod operates with the aid of two
push elements. Each of the push elements is conducted by a
corresponding guide rail. The ends of the two push elements act on
the tension rod, so as to be able to move the tension rod away from
the winding shaft.
[0012] Each push element is provided with its own drive gear. The
drive gear can be provided adjacent the foot end of the guide
rail--i.e., in the vicinity of the winding shaft. Thus, a
substantial piece of guide tube between the foot end of the guide
rail and the drive gear can be omitted. The push element exiting
from the individual guide rail can run substantially directly into
a gear housing that is arranged adjacent to the foot end of the
guide rail. In this way, it is possible to reduce the cost of the
connection tube.
[0013] Reducing the cost of the connection tube enables the drive
force to be saved in two ways. First, the drive force which is
required to move the corresponding length of push element through a
perhaps even straight-running guide tube can be omitted. Second,
the friction force is minimized because the connection tube does
not have a curved shape, which caused the push element to encounter
increased friction in the connection tube. As a result, the drive
force supplied by the motor is essentially entirely available for
moving the shade. The friction force produced by the push elements
in the guide rails is comparatively small because the guide rails
run almost straight.
[0014] An electrical drive motor is provided for driving the shade.
The drive motor simultaneously produces the force which is needed
to wind up the shade during the retraction on the winding shaft and
to move back the push elements.
[0015] Additionally, a compensation mechanism is provided to
compensate for the length difference between the advance movement
of the shade and the push element. The push element runs over a
drive gear, whose diameter is constant. Thus, for each turn of the
drive gear, the same length of the push element is always moved.
The situation is different with the shade. The shade forms a
spiral-shaped roll on the winding shaft. When the shade is unwound,
the effective diameter of the roll, and thus the quantity of shade
that is drawn from the winding shaft per turn, changes. The length
difference is not excessively large but must be controlled. This is
where the compensation mechanism is used. The compensation
mechanism produces the cloth tension on the shade.
[0016] Since a three-dimensional deflection of the push element
does not occur with the present invention, a push element that has
a gear-tooth system only on one side can be used. Alternatively, a
push element that has a gear-tooth system all around can be used.
The all-around gear-tooth system enables positioning of the push
element in the guide rail via a kind of helical movement. Due to
this helical movement, the push element is "turned past," so to
speak, the fixed drive gear.
[0017] Depending on the vehicle body conditions, the push elements
can either run freely in the vehicle body or can run in storage
tubes that are made of a flexible material. The storage tubes can
be placed anywhere in the automobile body and do not have to be
pre-shaped by the manufacturer of the roll-up window shade.
[0018] Very simple drive conditions can be produced if the drive
motor is coupled via gears directly to the winding shaft. With such
an arrangement, either the drive gears are coupled in an
elastically rotating manner with the winding shaft, or they sit on
a connection shaft that is conducted through or runs over the
winding shaft. Use of a separate connection shaft also allows the
gears to fixed on the connection shaft without rotational play and
the connection shaft to be coupled to the winding shaft in a
rotationally elastic manner. When using a separate connection
shaft, it is also possible to drive the connection shaft via the
motor.
[0019] The elastic elements which bring about the rotation
compensation can be coil springs or spiral springs, similar to the
mainspring of a watch. The spiral spring can be accommodated in the
drive gear and in particular in a pocket-shaped extension in the
drive gear. The rotating parts can be coupled rigidly and
inelastically with one another and the compensation can be produced
by placing a compression spring between the tension rod and the
push element associated the pertinent end of the tension rod.
[0020] The length of the tension rod can vary in accordance with
the geometry of the window.
[0021] In order to conduct the push elements in a bend-resistant
manner, the use of guide rails that contain an undercut guide
groove is advantageous. The undercut guide groove is composed of in
cross-section of a groove chamber and a groove slit.
[0022] The following description of the figures is limited to an
explanation of the aspects necessary to understand the invention. A
number of modifications are clearly possible. As will be
appreciated, one of skill in the art will understand the less
important details that are not described in the drawings.
[0023] The following drawings are not necessarily to scale. For
instance, to promote a better understanding of the invention it may
be that certain areas have been enlarged. Moreover, the drawings
are schematic in nature and do not contain every detail which may
be present.
[0024] Exemplary embodiments of the invention are shown in the
drawings.
[0025] Other objects and advantages of the invention will become
apparent upon reading the following detailed description and upon
reference to the drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a partially cutaway perspective view of the rear
passenger compartment of an exemplary motor vehicle equipped with a
roll-up window shade according to the present invention.
[0027] FIG. 2 is a partially cutaway front view of the roll-up
window shade of FIG. 1.
[0028] FIG. 3 is a schematic exploded perspective view of the
connection between one of the drive gears and the winding shaft of
the window roll-up shade of FIG. 1.
[0029] FIG. 4 is a partially cutaway front view of an alternative
embodiment of a roll-up window shade according to the present
invention in which the drive gears are arranged on the connection
shaft without rotational play.
[0030] FIG. 5 is a partially cutaway front view of an alternative
embodiment of a roll-up window shade according to the present
invention in which the connection shaft runs coaxially through the
winding shaft.
[0031] FIG. 6 is a partially cutaway plan view of an alternative
embodiment of a roll-up window shade according to the present
invention in which the compensation of the shade is accomplished
with the aid of compression springs.
[0032] While the invention is susceptible of various modifications
and alternative constructions, a certain illustrative embodiment
thereof has been shown in the drawings and will be described below
in detail. It should be understood, however, that there is no
intention to limit the invention to the specific form disclosed,
but on the contrary, the intention is to cover all modifications,
alternative constructions, and equivalents falling within the
spirit and scope of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Referring to FIG. 1 of the drawings, the rear passenger
compartment of a an exemplary motor vehicle is shown. The right
interior side is shown in FIG. 1. The right side is the mirror
image of the left interior side. Unless otherwise indicated, the
explanations for the right automobile body side are also apply to
the left automobile body side. The depiction in FIG. 1 is
simplified; thus, for example, automobile body interior structures,
such as the reinforcements, affixing elements are not shown since
they are not necessary for an understanding of the invention.
[0034] The illustrated automobile body section 1 has a roof 2. A C
column 3 leads downwards from a side of the roof to a car bottom
assembly. A corresponding C column can also be provided on the
opposite side of the motor vehicles. In this case, the interior
side of the C column 3 is provided with a lining 4. A rear window 5
extends downward from the rear edge of the roof 2. The rear window
5 is bound on the upper side by a window upper edge 6. The side
edges 7 of the windows extend toward each other. The side edge 7
shown in FIG. 1 extends into a corner area 8 into the window upper
edge 6.
[0035] The width of the rear window 5 is greater at the level of
the beltline of the automobile body than in the area of the window
upper edge 6. A B column 9 is provided at a distance in front of
the C column 3. A rear right-side door 11 is hinged to the B column
in a known manner. The right rear-side door 11 contains a window
section 12, which is divided up by a vertical brace 13 into a
substantially rectangular section 14 and an approximately
triangular section 15. The interior of the vehicle further includes
a back seat bench 15, with a back seat area 16 and a back seat back
17. The back seat area 17 lies on a floor assembly 18. A rear shelf
19 extends between the upper rear edge of the back seat back 17 and
the rear window 5.
[0036] In accordance with the invention, the rear window 5 is
provided with a rear window roll-up shade 21 of which only the
shade 22 is shown in FIG. 1. Other window shades are provided for
the side window 12. Specifically, a shade 23 is provided for the
rectangular window section 14 and a shade 24 is provided for the
triangular section 15. The drive for the shades 23 and 24 is the
same as the drive for the rear window shade 21. Accordingly, only
the structure of the drive for the rear window shade will be
described in detail herein.
[0037] As shown in FIG. 2, the rear window shade 21 includes two
guide rails 25 and 26 and a drive system 27. The guide rails 25 and
26 are arranged in a mirror image to one another and follow the
side edge of the rear window 5. Unlike as shown in FIG. 2, the
guide rails 25 and 26 converge as they extend in the direction of
the roof 2.
[0038] Since the two guide rails 25 and 26 are identical, a
description of the interior structure of the guide rail 26 is
sufficient for an understanding of the invention. Such description
is also applies for the guide rail 25. In the guide rail 26, an
undercut guide groove 27 is provided. The profile of the undercut
guide groove 27 is composed of a groove chamber 28 and a groove
slit 29. The width of the slit 29 is smaller than the inside width
of the groove chamber 28, wherein the undercut structure is
produced.
[0039] The two guide rails 25 and 26 conduct a tension rod 31 on
which one edge of the shade 22 is affixed. The tension rod 31
includes a middle piece in which two end pieces 32 and 33 are
supported in a telescoping manner. The middle piece can sit in a
hose-like loop formed on the shade 22. Each of the end pieces 32
and 33 has a telescoping rod 34 with a slide piece 35 sitting on
its free end. The telescoping rod 34 has cross-sectional dimensions
in that enable it to be conducted through the slit 29 with
clearance. The cross-sectional configuration of the slide piece 35
is adapted to the cross-sectional configuration of the groove
chamber 28, which can be, for example, circular. The end of the
shade 22 opposite the tension rod 31 is affixed to a winding shaft
36.
[0040] The drive device 27 is used to move the shade 22 between an
extended position in which it is extended over the rear window 5
and a retracted position in which the tension rod 31 either lies on
the rear shelf 19 or is retracted into the slit provided in the
rear shelf. The drive device 25 includes two identical linear
flexible push elements 38 and 39. Each of the push elements 38, 39
includes a core 41 having a circular cross section and a coil 42
that is affixed on the outside of the circular core 41. This
produces a kind of elastically flexible toothed rack with teeth all
around. The outside diameter of the push elements 38, 39
corresponds to the inside width of the groove chamber 28. In this
way, the two push elements 38, 39 are conducted in their
corresponding guide rails 25 and 26 in a buckle-free manner and can
transfer compression forces. The diameter of the push elements is
larger than the slit width 29 so that they cannot be buckled
laterally through the slit 29 even with compression stress.
[0041] The drive device 27 further includes a geared motor 43 whose
outlet shaft 44 is rigidly connected to the axle pins 45 of the
winding shaft 36. A spur gear 47 or 48 sits on the two shaft
journals 45 and 46. The spur gear is provided with a gear-tooth
system on its circumferential surface that permits a
positive-locking meshing with the corresponding push element 38,
39. The two push elements 38, 39 are pressed in a radial direction
against the corresponding drive gear 47, 48, so that the engagement
is consistently maintained. The push elements 38, 39 lie on the
same side relative to the axis of rotation of the corresponding
drive gear 47, 48 on which the shade 22 is extended from the
winding shaft 36.
[0042] The gear 47 is rotatably supported on the shaft journal 45
and the gear 48 is rotatably supported on the shaft journal 46. The
operative drive connection, via which a driving torque is
transferred, is shown in FIG. 3. The details shown in FIG. 3 apply
for both drive gears 47 and 48.
[0043] The drive gear 47 has a disk-like shape with a cylindrical
circumferential surface area 50 in which grooves 51 comprise the
gear tooth system. The grooves 51 run at an incline and take up the
pertinent section of the coil 42. The gear 47 includes an extension
52 coaxial to the outside circumferential area 50. A bearing
borehole 53 is contained concentrically in the extension 52 that
enables the gear 47 to be rotatably supported on the shaft journal
45. In this case, the extensions 52 each comprise a spring housing
for a spiral spring 54 that produces a rotationally elastic
connection between the shaft journal 45 and the gear 57. In this
respect, the shaft journal 45 includes a turned-up lip 46 at the
corresponding location, which is used as an abutment for an opening
47 provided on the inner spring end. The outside spring end also
has an opening 48, which can be connected, in a positive-locking
manner, with a lip 49. The lip 49 points radially inwardly from the
outside circumferential area of the extension 52.
[0044] As can be understood from the operational description below,
a relative rotation with respect to the winding shaft 36 is
achieved via a corresponding dimensioning of the effective diameter
of the gear 47 relative to the roll body that is formed on the
winding shaft 36 by the wound shade 22. The dimension of this
relative rotation is approximately and at most one rotation. In
this way, a spiral spring 54 which has a relatively short effective
path can be used.
[0045] The figures are not to scale and are intended to illustrate
the important features of the drive concept according to the
invention. The pertinent dimensions of the guide rails 25 and 26
and the outside diameter of the two elastic, pliable push elements
38, 39 can be readily determined from actual practice.
[0046] An elastically flexible storage tube 61 or 62 is arranged on
the opposite side of the pertinent gear 47, 48 from the individual
guide rails 25, 26. To a large extent, the storage tubes 61, 62 can
be placed freely in the motor vehicle in accordance with the
spatial conditions. A description of the measures which are taken
in order to keep the storage tubes 61 and 62 stationary is not
necessary for the understanding of the invention. Additionally, a
housing may be provided to surround the gear 47 or 48. The housing
can contain a corresponding tangential borehole for the passage of
the pertinent flexibly-elastic push element 38, 39.
[0047] The operation of the illustrated embodiment is as follows.
It is assumed that initially the shade 22 is completely (i.e., as
much as possible) wound on the winding shaft 36. When wound, the
spiral springs 54 contained in the two gears 47, 48 are slightly
biased. As a result of the bias, the push elements 38 and 39,
meshed and thus coupled in a positive-locking manner are
elastically biased in the direction of the two slide pieces 35 of
the tension rod 31 and fit snugly there. The bias force of the
spiral springs 54 holds the shade 22 between the winding shaft 36
and the tension rod 31 so that it is taut.
[0048] Beginning from this position, if a user wishes to extend the
rear window roll-up shade 21, he starts the geared motor 43 with an
electric switch. The running geared motor 43 turns the winding
shaft 36, together with the two shaft journals 45 and 46, which are
coupled without rotational play, in the unwinding direction of the
shade 22. The two drive gears 47 and 48 move in the same direction
of rotation. Since their effective diameter coincides with the
outside diameter of the roll body on the winding shaft 36 when the
shade 22 is completely wound (i.e., with the window shade opened),
the two push elements 38 and 39 first move at exactly the same
speed as the tension rod 31 at the movable front edge of the shade
22.
[0049] As the shade 22 is increasingly unwound, the roll body on
the winding shaft decreases in size. Consequently, less shade is
released per rotation of the winding shaft 36 than the two
elastically flexible but shear-resistant push elements 38, 39 would
traverse with a rigid coupling and at the same angular rotation. As
a result of the rigid coupling with the shade 22, the push elements
38, 39 are forced to move at the same speed as the shade 22, which
as a result leads to the slowing down of the rotational movement of
the two drive gears 47 and 48 as compared to the rotational
movement of the winding shaft 36. In this way, the spiral spring 54
is substantially wound up in a manner similar to the mainspring of
a watch. However, depending on the dimensions and the length of the
shade has extended, the extent of the relative rotation is limited
to approximately one rotation between the winding shaft 36 and the
drive gear 47 or 48. At the end of the extension movement, when the
tension rod 21 has arrived at the upper edge of the window, the
cloth tension in the shade 22 will thus be somewhat greater than at
the beginning.
[0050] The retraction of the shade is carried out analogously in
the reverse direction, wherein the two spiral springs 54 once again
relax by the corresponding extent. At the end of the retraction
movement, the tension rod 31 is again on the rear shelf 19 and the
remaining residual tension in the two spiral springs 54 provides
the required cloth tension in the shade 22. Since the spiral
springs 54 have identical dimensions, the same forces also act on
the tension rod 31 on both ends.
[0051] As a result of the illustrated arrangement, the two shaft
journals 45 and 46 that are coupled rigidly to the geared motor 43
move at the same rotational speed and thus produce the same drive
effect for the two drive gears 47 and 48. Furthermore, the push
elements 38 and 39 now move in an essentially stretched state.
Since the drive effect is introduced right at the foot end of the
two guide rails 25 and 26, complex deflections are not required to
bring the two push elements 38, 39 to one common drive source. Each
push element 38, 39 has its own drive source, which is arranged in
such a manner that a minimal deflection of the push element 38, 39
from the completely stretched, straight condition is required. In
this way, the friction is enormously reduced, compared with the
arrangements found in the prior art. Also the storage tubes 61 and
62 move primarily in a straight line, and since they are flexible,
they can be placed in the motor vehicle in any manner.
[0052] The force which must be produced by the motor 43 corresponds
to the force which is required to further wind up the two spiral
springs 54 with the rotational travel, in comparison with the
winding shaft 36, as well as the very small friction to which the
two push elements 38, 39 are subjected. This friction is very small
since the two guide rails 25, 26 move primarily in a straight line.
The radius of curvature is also extremely large at the most narrow
location.
[0053] The illustrated embodiment is a fundamental arrangement. The
illustrated motor 43 is a geared motor that acts on the outside end
of the shaft journal 45 so that the drive gear 47 is located
between the winding shaft 36 and the geared motor 43. Those skilled
in the art will readily appreciate that the drive can also be
introduced at the shaft journal 45 between the drive gear 39 and
the winding shaft 36.
[0054] In the embodiment of FIG. 2, each drive gear 47, 48 is
coupled by itself in a rotationally elastic manner. An embodiment
in which the two drive gears 47 and 48 are seated on a connection
shaft 65 is shown in FIG. 4. The connection shaft 65 moves like a
bearing axle through the tube-shaped winding shaft 36 as shown in
the cut away portion of FIG. 4. The other end of the connection
shaft 65 is in turn coupled without rotational play to the outlet
shaft 44 of the geared motor 43.
[0055] The diameter of the connection shaft 65 is clearly smaller
than the inside width of the tube-shaped winding shaft 36. An
annular space 66 is produced in which a coil spring 67 is located.
The coil spring is anchored at one end in a bearing ring 68 that is
coupled to the connection shaft 65 without rotational play via a
pin 69. The pertinent end of the winding shaft 36 is supported on
the bearing ring 68. The other end of the coil spring 67 is
connected without rotational play to a ring piece 71, which in turn
is also connected without rotational play to the winding shaft 36
with the aid, for example, of reinforcing seams 72. The other end
of the winding shaft 36 is supported, with little clearance, on the
connection shaft 65. Otherwise, the structure of this rear window
roll-up shade 21 is not different from the rear window roll-up
shade 21 of FIGS. 2 and 3.
[0056] The relative rotation between the winding shaft 36 and the
drive gears 47 and 48 required during operation is brought about
here via a coil spring 67, which produces the rotationally elastic
connection between the connection shaft 65 and the winding shaft
36. Otherwise, the operation is also the same as the embodiment of
FIGS. 2 and 3.
[0057] An arrangement in which the connection shaft 65 does not
pass coaxially through the tube-shaped winding shaft 36, as in the
embodiment of FIG. 4, but rather is located parallel to and next to
it is shown in FIG. 5. The two gears 47 and 48 sit on the
connection shaft 65--again in such a way that they, as with all the
illustrated embodiment, are largely aligned with an extension of
the guide rails 25, 26, so as to produce a minimal deflection of
the push elements 38, 39 and thereby the friction forces remain
small. A gear 75, which meshes with a front gear 76 located on the
shaft journal 65, is seated on the connection shaft 65.
[0058] In the embodiment of FIG. 5, there are several possibilities
of compensating for the rotation between the drive gears 47 and 48
and the winding shaft 36. First, the two gears 47 and 48 could be
coupled with the connection shaft 65, in a rotationally elastic
manner, as with the embodiment of FIGS. 2 and 3. In that
embodiment, the drive gears 47 and 48 are rotationally elastically
connected to the bearing journals 45 and 46, which in turn are
coupled to the winding shaft 36 without rotational play. Another
possibility for attaining the required rotation compensation is by
coupling the front gear 76 in a rotationally elastic manner to the
shaft journal 65, as in the embodiment of FIG. 3.
[0059] Instead of accommodating the rotationally elastic coupling
in the front gear 76, the rotationally elastic coupling can also be
carried out between the gear 75 and the connection shaft 65. In
each case, the operation is described as above. The advantages
explained in this connection are also attained.
[0060] An alternative embodiment as to how the travel path
difference between the front edges of the shade 22 and the push
elements 38, 39 can be controlled is shown in FIG. 6. The basic
structure of the shade 21, according to FIG. 6, corresponds to the
structure shown in FIG. 2. However, the two drive gears 47 and 48
are seated on the shaft journals 45 and 46 without rotational play,
so that in this case a relative rotation between the winding shaft
36 and the two drive gears 47 and 48 is possible. The travel path
difference is controlled with the aid of compression springs 79.
The cutaway part of the guide rail 26 in Fig. shows how the coil
compression spring 79 is inserted between the free end of the push
element 39 and the slide piece 35. The dimensions are selected such
that the compression spring 79, which is supported on the free end
of the push element 39, constantly exerts a pre-push force on the
tension rod 31. The compression spring 79 exhibits the largest
length when the shade 22 is wound on the winding shaft 36. When the
winding shaft 36 together with the two gears 47 and 48 are rotated
by the geared motor 43, the tension rod 31 begins to slow
increasingly down, as compared with the free ends of the two push
elements 38, 39. In this way, the compression springs 79 contained
in the two guide rails 25 and 26 are increasingly compressed. Since
the two drive gears 47 and 48 are located directly below the lower
end of the two guide rails 25 and 26, connection tubes for a common
drive gear are avoided, and correspondingly, the friction loss is
reduced.
[0061] Those skilled in the art will appreciate that the drive
concept for shades explained above in connection with FIGS. 2-6, is
not limited to use with rear window roll-up shades. This drive
concept can also be used in connection with other type of shades,
for example, side roll-up window shades for the rectangular window
section 14 of the rear side door or with a sunroof roll-up window
shade.
[0062] Two drive gears are provided as an extension of the guide
rails for driving a roll-up window shade for a motor vehicle. The
drive gears are coupled to the winding shaft in a rotationally
elastic manner. The driving is carried out via a geared motor,
which acts either on the gears or on the winding shaft. The
positioning of the drive gears as an extension of the guide rails
avoids the guide tubes used in prior art arrangements. Thus, the
friction losses found in the prior art, which consume up to 80% of
the drive force, are avoided. Furthermore, manufacturing is
simplified because the connection tubes having a complicated shape
are not needed.
* * * * *