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.

Description

FIELD OF THE INVENTION

The present invention relates to roller blinds for motor vehicles.

BACKGROUND OF THE INVENTION

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

FIG. 2 is a schematic front view of the rear window roller blind of FIG. 1.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.