U.S. patent application number 11/903923 was filed with the patent office on 2008-03-27 for roller blind with undercut-free guide rail.
This patent application is currently assigned to BOS GmbH & Co. KG. Invention is credited to Werner Schlecht.
Application Number | 20080073040 11/903923 |
Document ID | / |
Family ID | 38573408 |
Filed Date | 2008-03-27 |
United States Patent
Application |
20080073040 |
Kind Code |
A1 |
Schlecht; Werner |
March 27, 2008 |
Roller blind with undercut-free guide rail
Abstract
A roller blind for motor vehicles is provided that includes
guide rails at the sides of the deployed blind sheet. These guide
rails contain guide grooves without undercuts. Strip-like actuators
are used to transfer the forces between the pull rod and the
driving device. The actuators are prevented from buckling
perpendicularly to the plane of the blind sheet by the guide rails.
Due to their shape, the actuators are prevented inherently, i.e.
without external assistance, from buckling parallel to the plane of
the blind sheet.
Inventors: |
Schlecht; Werner;
(Vaihingen/Enz - Aurich, 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.: |
11/903923 |
Filed: |
September 25, 2007 |
Current U.S.
Class: |
160/370.21 |
Current CPC
Class: |
B60J 1/2058 20130101;
B60R 5/047 20130101 |
Class at
Publication: |
160/370.21 |
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 roller blind for motor vehicles comprising: a pivotably
supported winding shaft having two end faces; a blind sheet having
a first edge connected to the winding shaft; a pull rod connected
to a second edge of the blind sheet remote from the winding shaft;
two guide rails each extending on a respective side of the blind
sheet when the blind sheet is an extended position unrolled from
the winding shaft, each guide rail including guide groove for
guiding the pull rod without any undercuts; two strip-like
actuators each being associated with a respective one of the guide
rails, each actuator running through its respective guide rail and
having a rectangular cross-sectional shape corresponding in
thickness to a width of the guide groove, each actuator carrying
teeth and cooperating with the pull rod; and two driving gearwheels
each being associated with a respective one of the actuators, each
of the driving gearwheels being arranged at an end face of the
winding shaft; wherein the actuators are operatively arranged
between the driving gearwheels and the pull rod.
2. The roller blind according to claim 1, further including a
driving device for the winding shaft.
3. The roller blind according to claim 2, wherein the driving
device drives the driving gearwheels.
4. The roller blind according to claim 1, wherein the pull rod is
configured such that its length is selectively adjustable.
5. The roller blind according to claim 1, wherein a first end of
each of the guide rails is in the proximity of the winding
shaft.
6. The roller blind according to claim 1, wherein the guide rails
extend parallel to one another.
7. The roller blind according to claim 1, wherein each actuator
moves in its respective guide groove in a manner resistant to
buckling in a direction perpendicular to the blind sheet in the
extended position.
8. The roller blind according to claim 1, wherein each actuator is
flat and has a rectangular cross-sectional configuration with one
flat side bearing teeth.
9. The roller blind according to claim 1, wherein each actuator has
a sandwich-like structure with a back comprising a spring steel
band.
10. The roller blind according to claim 1, wherein each driving
gearwheel is a crown gear.
11. The roller blind according to claim 1, wherein each driving
gearwheel has a helical gearing configured such that a longitudinal
direction of a tooth engaged with the respective actuator runs at a
right angle to the longitudinal axis of the respective guide
rail.
12. The roller blind according to claim 1, wherein the two driving
gearwheels are connected to the winding shaft.
13. The roller blind according to claim 1, wherein the two driving
gearwheels are arranged coaxially to winding shaft.
14. The roller blind according to claim 1, wherein a drive motor is
coupled to the winding shaft.
15. The roller blind according to claim 1, wherein a compensation
element is arranged between each driving gearwheel and the winding
shaft.
16. The roller blind according to claim 15, wherein each
compensation element comprises a spiral spring.
17. The roller blind according to claim 16, wherein each spiral
spring is seated in a recess of the respective driving
gearwheel.
18. The roller blind according to claim 1, wherein an engagement
element keeps each actuator engaged with its corresponding driving
gearwheel.
19. The roller blind according to claim 1, wherein a separate
transmission case is provided for each driving gearwheel.
20. The roller blind according to claim 1, wherein each actuator
has a separate storage tube for accommodating a load-free section
of the respective actuator when the roller blind is in a retracted
position.
21. The roller blind according to claim 20, wherein each storage
tube comprises a flexible material.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to roller blinds for motor
vehicles.
BACKGROUND OF THE INVENTION
[0002] Electrically driven rear window roller blinds are known from
the prior art. One such prior art roller blind includes a winding
shaft pivotably seated underneath the rear shelf of the vehicle to
which the blind sheet is fastened at one edge. The other edge of
the blind sheet is connected to a pull rod that is guided at its
ends in guide rails. The guide rails extend alongside the lateral
edges of the rear window, starting from the rear shelf or below the
rear shelf into the proximity of the upper edge of the window. In
order to place the blind under tension, a spring motor which biases
winding shaft in the direction for rolling up the blind sheet is
usually seated in the winding shaft or alongside it.
[0003] The blind sheet is unrolled or stretched out with the aid of
strip-like actuators that run in a buckling-resistant manner in the
slot chamber of the guide rails. A shared gear motor that is
situated next to the winding shaft approximately at the level of
its center is provided to drive the actuators. Guide tubes ending
at the gear housing of the gear motor are provided to connect the
gear motor to the lower ends of the guide rails. With the aid of
these guide tubes, the actuators run in a buckling resistant manner
between the drive motor and the guide rails so that they can
perform their pushing function.
[0004] Since the motor is seated relatively close alongside the
winding shaft in order to save space, the guide tubes run roughly
parallel to the winding shaft in the area of the gear motor and
must be deflected at the guide rails in a direction perpendicular
to the winding shaft. Again for space reasons, the radius of
curvature of the guide tubes is comparatively quite narrow where
they open into the guide rails. These installation conditions
require an actuator that is equally flexible in all directions. For
this purpose, the guide grooves must undercut to ensure
buckling-resistant guidance.
[0005] The undercut guide grooves make the mounting of the pull rod
more difficult. The guidance members of the pull rod can be
introduced only from the ends of the guide rails. Moreover, the
production of undercut guide rails is difficult or expensive,
particularly, if they are to be integrally formed with side trim
parts or the roof lining of the vehicles such as by injection
molding.
[0006] The problems with the prior art arrangement have been
described in connection with a rear window blind. As will be
appreciated, similar difficulties are encountered with sun roof
blinds that are driven in a comparable manner.
OBJECTS AND SUMMARY OF THE INVENTION
[0007] In view of the foregoing, a general object of the present
invention is to provided a roller blind for motor vehicles that can
be installed simply and easily.
[0008] The motor vehicle roller blind of the present invention
includes a pivotably seated winding shaft having two front ends.
The blind sheet is fastened to the winding shaft at one edge.
Another edge of the blind sheet, which is remote from the winding
shaft, is connected to the pull rod. Two guide rails for guiding
the pull rod are provided on either side of the stretched blind
sheet. Each of the two guide rails contains a guide groove which,
in contrast to conventional designs, is free from undercuts.
Strip-like actuators for moving the pull rod or transferring
movement from the pull rod, run in the guide rails. The actuators
have a rectangular cross section with a thickness that is matched
to the width of the guide groove. On one flat side, the actuators
have teeth with which they can be positively driven.
[0009] Since the actuators have a rectangular cross section, they
are inherently sufficiently stiff in the direction parallel to the
plane of the stretched blind sheet to be able to transfer pushing
forces without buckling out laterally from undercut-free guide
grooves. The actuators are also sufficiently flexible in the
direction perpendicular thereto to be able to easily match the
contour of the two drive gearwheels with which they are positively
coupled for driving or to be able to be housed in places that have
profiles other than straight lines. Thus, the actuation members can
at least transmit power between the drive wheels and the pull rod
by pushing.
[0010] The roller blind can be handled manually, in which case an
arrangement of the type described in detail in DE 10 2006 046 065
and DE 10 2006 046 064 can be used, the disclosure of which is
incorporated herein by reference.
[0011] For a solenoid-operated roller blind, an electrical driving
device that can be connected to the winding shaft can be provided.
Alternatively, the driving gearwheels can be coupled to the
electrical driving device. Electrical driving devices for such a
roller blind are described in detail in DE 10 2006 046 069, the
disclosure of which is incorporated herein by reference.
[0012] The arrangement of the present invention can also be used
for roller blinds in which the lateral edges of the blind sheet do
not run parallel to each other. In such cases, a variable-length
pull rod is necessary.
[0013] Advantageous guidance can be achieved if the guide rails
begin at one end in the proximity of the winding shaft. The guide
rails can be arranged parallel or converging towards one another,
depending on the shape of the window.
[0014] The strip-like actuator expediently can have a flat
rectangular shape such that the dimensions in the thickness
directions can be smaller by a factor of 2 or more than in the
width directions of the cross-sectional profile.
[0015] The driving gearwheel can be a straight-toothed gearwheel if
the guide rails run at a right angle to the axis of rotation of the
driving gearwheel. If the guide rails are not at a right angle to
the axis of rotation, the driving gearwheel can be provided with
helical gearing such that the crest line of the teeth lies at a
right angle to the longitudinal axis of the guide rail. The driving
gearwheels can be arranged coaxially to the winding shaft, and the
driving motor can be coupled to the winding shaft.
[0016] Elastic compensation elements can be inserted between the
driving gearwheels and the winding shaft. In the simplest case, the
compensation elements are helical or spiral springs. Considerable
space can be saved if the spiral spring is seated in a recess of
the driving gearwheel.
[0017] In order to protect the load-free section of each actuator
against contamination and damage, a storage tube can be provided
for each actuator. The storage tube can expediently consist of a
flexible material. Moreover, the storage tube can be round.
[0018] The description of preferred embodiments below is limited to
an explanation of the aspects that are essential to an
understanding of the invention. It is clear that a number of
modifications are possible. A person of skill in the art can infer
minor details from the figures along with the accompanying
description. As will be appreciated, the drawings below are not
necessarily to scale. Certain parts may be presented in an
exaggerated size to illustrate important details. Moreover, the
drawings are simplified and do not contain every detail necessary
in a practical embodiment.
[0019] 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
[0020] FIG. 1 is a schematic partially cut away perspective view of
the rear passenger compartment of an exemplary motor vehicle
equipped with a rear window roller blind according to the present
invention.
[0021] FIG. 2 is a schematic front view of the rear window roller
blind of FIG. 1.
[0022] FIG. 3 is a partial cross-sectional perspective view of one
of the guide rails as well as a part of one of the guidance members
of the rear window roller blind of FIG. 2.
[0023] FIG. 4 is a schematic exploded perspective view of the
connection between one of the driving gearwheels and the winding
shaft of the rear window roller blind of FIG. 2.
[0024] 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
[0025] Referring to FIG. 1 of the drawings, a rear passenger
compartment of an illustrative motor-vehicle is shown. The right
interior side is shown in FIG. 1, which is a mirror-image of the
cut-away left interior side. Unless otherwise indicated, the
descriptions for the right body side also apply in a general manner
to the left body side. FIG. 1 is simplified; thus, for example,
interior body such as reinforcements and mounting elements are not
shown, since a representation of them is not necessary for an
understanding of the invention.
[0026] The body section 1 of the illustrated motor vehicle includes
a roof 2, from which a C-column 3 leads laterally downward to a
substructure. A corresponding C-column is also provided on the
opposite side of the vehicle. A lining 4 is provided on the inside
of the C-column 3. The roof 2 transitions into a rear window 5 at
its rear edge. The rear window 5 is limited on the upper side by a
window upper edge 6. A section 7 of the lateral edges that
transitions into window upper edge 6 at a corner area 8 is shown in
FIG. 1. The lateral edges extend in mirror images relative to one
another.
[0027] The width of rear window 5 is larger at the level of the
belt line of the body than in the area of upper window edge 6. A
B-column 9 lies a distance in front of C-column 3. A rear right
side door 11 is hinged onto the B-column 9. The right rear side
door 11 has a window cutout 12 that is divided by a vertical strut
13 into a substantially square section 14 and a triangular section
15. A rear seat 15 having a rear seat surface 16 and a backrest 17
is also arranged in the interior. The rear seat surface 17 rests
upon an understructure 18. A rear shelf 19 extends between the rear
upper edge of the backrest 17 and the rear window 5.
[0028] The rear window 5 is provided with a rear window roller
blind 21. Only the blind sheet 22 of the rear window blind 21 is
shown in FIG. 1. In this case, additional roller blinds are
provided on the side window 12, specifically a blind sheet 23 is
provided in square window section 14 and a blind sheet 24 is
provided in triangular section 15.
[0029] The drive system for the side window blind sheets 23 and 24
can have same configuration as the drive system of the rear window
roller blind 21. Accordingly, only the structure of the drive
system for the rear window roller blind 21 is described herein. As
shown in FIG. 2, the rear window roller blind 21 includes two guide
rails 25 and 26 that extend along the sides of rear window. The
guide rails 25 and 26 follow the contour of the rear window 5 and
are arranged and configured so as to be mirror-inverted relative to
each other. The guide rails 25 and 26 can converge to a greater or
lesser extent in the direction of roof 2 as desired.
[0030] As the two guide rails 25 and 26 are identical, the internal
structure of only guide rail 26 will be described herein. Such
description also applies to guide rail 25. As shown in FIG. 3, the
guide rail 26 includes an undercut-free guide groove 27 with a
shallow rectangular profile. The guide groove 27 is delimited by
two mutually parallel side panels 28, 29 as well as a groove bottom
30, and opens outward through a slot 31.
[0031] The two guide rails 25 and 26 serve to guide a pull rod 32
to which one edge of the blind sheet 22 is fastened. The pull rod
32 consists of a center piece, in which two end pieces 33 and 34
run in a telescoping manner. The center piece lies, for example, in
a tubular loop formed on the blind sheet 22. The two end pieces 33,
34 are elastically tensioned outward in the direction of the
respective guide rail 25, 26 by springs 35.
[0032] Each of the two end pieces 33, 34 carries a slider 36 at its
free end. The end pieces 33, 34 have cross-sectional dimensions
that allow them to fit into the guide groove 27 with some play. The
cross-sectional shape of the slider 36 is matched to the
cross-sectional shape of the guide groove 27, which is for example
a shallow rectangle.
[0033] The end of the blind sheet 22 remote from pull rod 32 is
fastened to a winding shaft 37. A driving device 38 serves to move
the blind sheet 22 between an extended position in which it is
spread out in front of rear window 5 and a retracted position in
which the pull rod 32 either rests on the rear shelf 19 or is
retracted through the slot present in the rear shelf. The driving
device 38 includes two identically formed strip-like flexible
actuators 39 and 40. Each of the actuators 39, 40 has a shallow
rectangular cross section, with two flat sides 41 and 42. The flat
side 42 carries teeth 43. This produces a flexible rack with teeth
on one side. The thickness of the actuators 39, 40 corresponds to
the clearance of the guide groove 27. As a result, the two
actuators are 39, 40 are guided in their associated guide rails 25
and 26 in a manner resistant to buckling in a direction
perpendicular to the plane of their flat sides 41, 42. Since the
two actuators 39, 40 have a better geometrical moment of inertia in
the direction perpendicular thereto, they can transfer actuation
forces onto pull rod 32. Due to their shape, the actuators cannot
buckle out laterally through the slot 31 even under a compressive
load. To improve the guidance, the actuators 39, 40 can be
connected at their ends to the associated slider 36.
[0034] The driving device 38 further includes a gear motor 43
having an output shaft 44 that is rigidly connected to axle
journals 45, 46 of the winding shaft 36. A front gear wheel 47, 48
is seated on each of the two axle journals 45 and 46. Each front
gear wheel has teeth 49 on its outer circumferential surface that
permit a positive engagement with the associated actuator 39, 40.
The two actuators 39, 40 are pressed in the radial direction
against the associated driving gearwheel 47, 48 so as to provide a
consistent engagement. Relative to the axis of rotation, each of
the actuators 39, 40 rests against the corresponding driving
gearwheel 47, 48 on the same side on which the blind sheet 22 also
runs off of winding shaft 37.
[0035] The gear wheel 47 is pivotably seated on the axle journal
45. Generally, the same arrangement applies to gear wheel 48 on
axle journal 46. The kinematic connection by which a drive moment
is transferred is illustrated in detail in FIG. 3. The illustration
provided in FIG. 3 applies similarly to the two driving gearwheels
47 and 48. The driving gearwheel 47 has a disk-like shape with
straight front teeth 49 that cooperate positively with the teeth 43
of the respective actuator 39, 40. The gear wheel 47 has a pot-like
recess 52 arranged coaxially relative to the teeth 49, which
contains a concentric bearing bore 53 with which the gear wheel 47
is pivotably seated on the axle journal 45. The recess 52 forms a
spring housing for a spiral spring 54 that produces an elastic
rotary connection between the axle journal 45 and the gear wheel
47. For this purpose, the axle journal is 45 is furnished in the
appropriate place with a projecting tab 56 that serves as an
abutment for an opening 57 provided at the inner end of the spring.
The external spring end likewise contains an opening 58 that can be
positively connected to a tab 59 which points radially inward from
the outer circumferential surface of the recess 52.
[0036] As follows from the description of function below, the
spring carries out a relative rotation with respect to winding
shaft 37, given an appropriate dimensioning of the effective
diameter of gearwheel 47 relative to the roll body formed by
rolled-up blind sheet 22 on winding shaft 37. The magnitude of this
relative rotation amounts to roughly one revolution at most. Thus a
spiral spring 54 having a relatively short effective path length
can be used.
[0037] The figures showing the illustrated embodiment are not to
scale. Rather, the figures are intended to show the essence of the
driving principle. The relevant dimensions of the guide rails 25
and 26 as well as the outside diameter of the two flexible
actuators 39, 40 resulting therefrom will be well-known to one of
skill in the art from practice.
[0038] An elastically flexible storage tube 61, 62 can be provided
on the opposite side of the respective gearwheel 47, 48 as viewed
from the respective guide rail 25, 26. The elastically flexible
storage tube 61, 62 can be positioned relatively freely in the
vehicle corresponding to the spatial conditions. The manner in
which the storage tubes 61 and 62 are held stationary are not of
importance for an understanding of the invention. Moreover, a
housing, for example, can be provided to surround the gear wheel
47, 48. The housing can contain an appropriate tangential bore for
the passage of the associated elastically flexible--actuator 39,
40.
[0039] The following is a description of the operation of the
illustrated embodiment. In this description, it is assumed that the
blind sheet 22 begins completely rolled up onto the winding shaft
37, i.e. as far as possible. In the rolled-up condition, the spiral
springs 54 contained in the two gear wheels 47, 48 are under a
slight bias tension. Due to the biasing, the actuators 39 and 40
engaged with them, and thus positively coupled to them, are
elastically tensioned in the direction of and rest against the two
sliders 35 of the pull rod 32. The bias force of the spiral springs
54 keeps the blind sheet 22 taut between the winding shaft 36 and
the pull rod 32. The springs 35 press the sliders 36 and the ends
of the strip-like actuators 39, 40 coupled thereto against the slot
bottom 30.
[0040] If a user, starting from this position, wishes to deploy the
rear window roller blind 21, he starts the gear motor 43 via an
electrical switch. The running gear motor 43 turns the winding
shaft 37 together with the two axle journals 45 and 46 coupled
thereto in the direction associated with unrolling blind sheet 22
from winding shaft 37. The two driving gearwheels 47 and 48 move in
the same direction of rotation. Since their effective diameter
matches the outside diameter of the roll body on the winding shaft
when the blind sheet 22 is completely rolled up (corresponding to
an open roller blind), the two actuators 39 and 40 initially move
with exactly the same speed as the pull rod 32, i.e., the movable
front edge of the blind sheet 22.
[0041] With the progressive unrolling of the blind sheet 22, the
roll body present on the winding shaft decreases. Therefore, less
of the blind sheet is released per revolution of the winding shaft
37 than the two elastically flexible, but compression-resistant,
actuators 39, 40 would travel for the same angle of rotation.
Because of their rigid coupling to the blind sheet 22, the
actuators are forced to move at the same speed as the blind sheet
22, which as a result causes the rotating motion of the two driving
gearwheels 47 and 48 to be retarded in relation to the rotating
motion of the winding shaft 37. Thereby, the spiral spring 54 is
wound more tightly, similar to a clock spring. Depending upon the
dimensions and length of the extension travel, the magnitude of the
relative rotation between the winding shaft 37 and the driving
gearwheels 47, 48 is limited to approximately one revolution. At
the conclusion of the extension movement, i.e. when the pull rod 21
reaches the upper edge of the window, the tension in the fabric of
the blind sheet 22 will therefore be somewhat greater than at the
beginning.
[0042] The blind sheet is retracted in the reverse direction with
the two spiral springs 54 relaxing to a corresponding extent. At
the conclusion of the retraction movement, the pull rod 31 rests
upon a rear shelf 19, with the remaining residual tension in the
two spiral springs 54 providing the necessary fabric tension in the
blind sheet 22. Since the spiral springs 54 are dimensioned exactly
the same on both sides, the same forces act on the pull rod 31 at
each end as well in case of a rigid coupling.
[0043] Since the drive force is introduced directly at the lower
end of the two guide rails 25 and 26, no complex deflections are
necessary to connect the two actuators 39, 40 to a common power
source. Each actuator 39, 40 has its own power source, which is
positioned such that a minimum deflection of the actuator 39, 40 is
necessary because of the completely stretched straight contour. As
a result, the friction decreases enormously compared to prior art
designs. The storage tubes 61 and 62 also run straight to a large
extent and can be placed as desired in the vehicle since they are
flexible.
[0044] As the illustrated embodiment additionally shows, the two
actuators 39 and 40 are under a compressive load in the area of
their load-bearing section (i.e. between the pull rod 32 and the
respective driving gearwheels 47, 48. This applies even in a manual
enterprise by way of the pull rod. Over the full length of the
load-bearing section, this compressive load could cause the
respective actuator 39, 40 to attempt to buckle out of the guide
groove 27 perpendicularly to side walls 28, 29. However, the
respective actuator 39, 40 is prevented from buckling out by the
two rigid side walls 28, 29. The special shape of the flat,
strip-like actuators 38, 40 is sufficient however, to prevent a
lateral buckling-out over the entire length of the load-bearing
section without the aid of the guide rails 25, 26.
[0045] Thus, undercut guide grooves of the type typically found in
the prior art can be eliminated. Guide grooves that are free of
undercuts have the great advantage that such guide grooves can be
injection-molded into the trim parts of the motor vehicle without
any special difficulties. The trim parts can include sections of
the roof liner as well. The ease of injection molding results
because undercut-free parts can be easily released from the mold
even on an otherwise not straight contour.
[0046] A further improvement of the buckling resistance in the
direction parallel to the plane of the deployed blind sheet 22 can
be achieved if the respective actuator 39, 40 is constructed in a
sandwich-like manner. For example, each actuator 39, 40 can
consist, as shown in FIG. 3, of an elastomeric layer bearing teeth
43 and a spring steel strip 64 constituting the back side. The
spring steel strip can be very thin, so that it is also possible,
for example, to produce a slightly curved contour without
difficulty. It is flat in the transverse direction, i.e. the
generatrix is a straight line.
[0047] If the two guide rails 25 and 26 do not extend parallel to
one another, as shown in FIG. 2, but at an angle, it is sufficient
if the teeth on the two gear wheels 47, 48 run somewhat slanted in
such a manner that the axis of the guide rail 25, 26 stands
perpendicularly to the crest line of the tooth which is engaged
with the respective actuator 39, 40. The ends of the load-bearing
section of each actuator 39, 40 remote from the gear wheels 47, 48
are forcibly retained in the guide groove 27 by the
spring-tensioned end pieces 33, 34.
[0048] While an exemplary embodiment of the invention has been
described in connection with a rear window roller blind, those
skilled in the are will appreciate that the invention is equally
applicable to side window roller blinds and sun roof shades as
well, in the form of flat actuators in conjunction with
undercut-free guide grooves.
[0049] A roller blind for motor vehicles is provided that includes
guide rails at the sides of the deployed blind sheet. These guide
rails contain guide grooves without undercuts. Strip-like actuators
are used to transfer the forces between the pull rod and the
driving device. The actuators are prevented from buckling
perpendicularly to the plane of the blind sheet by the guide rails.
Due to their shape, the actuators are prevented inherently, i.e.
without external assistance, from buckling parallel to the plane of
the blind sheet.
* * * * *