Sunshade assembly for a vehicle roof

A sunshade assembly for a vehicle roof has a window shade that is movable along guide rails toward the front and rear of the vehicle. Drive elements are connected to a front edge of the window shade, and rotatable tension wheels are mounted to the guide rail and coupled with the drive elements to pull taut a front portion of the window shade disposed between the front edge and the tension wheels.

REFERENCE TO RELATED APPLICATIONS

The present invention claims the benefit of German Patent Application No. 103 31 514.4, filed Jul. 11, 2003.

TECHNICAL FIELD

The invention relates to a sunshade assembly for a vehicle roof.

BACKGROUND OF THE INVENTION

A sunshade assembly for a vehicle roof often includes a sunshade blind which is associated with a light-transmitting (e.g., transparent or translucent) opening in the vehicle roof. The light-transmitting opening may be, for instance, a stationary panoramic window or also a transparent cover of a sliding roof. The sunshade blind can be shifted between an open position, where it does not hinder the passage of light through the opening, and a closed position, where it diminishes or completely blocks incident light radiating through the opening. Depending on the specific sunshade blind construction, the sunshade blind can be secured in various intermediate positions between the closed and open positions.

Conventional sunshade blinds use a sunshade made from cloth or other flexible material. The sunshade is wound around a shaft when it is in the open position. The shaft necessarily has to be straight so that it can be rotated to wind the sunshade. Because a vehicle roof usually is arched, however, the shaft profile greatly restricts head room within a passenger compartment of the vehicle.

It is therefore the object of the invention to create a sunshade assembly that allows sufficient head room in the passenger compartment of the vehicle without sacrificing the adjustability of the sunshade.

SUMMARY OF THE INVENTION

The invention is generally directed to a sunshade assembly for a vehicle roof. The sunshade assembly comprises first and second guide rails, a window shade that is movable along the guide rails toward the front and rear of the vehicle, first and second window shade drive elements that are at least partially movable along the guide rails and are connected to a front edge of the window shade, and first and second rotatable tension wheels that are mounted to be stationary with respect to the guide rails. The tension wheels are coupled with the drive elements such that a front window shade portion disposed between the window shade front edge and the tension wheels is held taut. This makes it possible to stow away the remaining part of the window shade (i.e., a rear window shade portion between the rear edge window shade and the tension wheels) in a suitable manner while maintaining as much head room as possible in the vehicle.

In one example, the rear window shade portion is disposed behind the tension wheels and can be loosely received in an accommodation space. Alternatively, it is also possible to receive the rear window shade portion in the shape of a coil. The coiled rear window shade portion can either be received on a separate winding body that is acted upon by a spring in a wind-up direction or can be directly wound on the tension wheels.

Advantageous designs of the invention will be apparent from the sub-claims.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1schematically shows a vehicle roof5having a roof opening7. The roof opening7can be closed in any known manner by a cover9, which is shown inFIG. 1in its opened position shifted to the rear with respect to the vehicle. The cover is made from a light-passing (e.g., transparent or translucent) material.

A window shade10is arranged underneath the cover9. The window shade10, together with components (explained below) that guide and operate the window shade10, forms a sunshade assembly11(FIG. 3).

As shown inFIGS. 2 and 3, the window shade10is movable along two guide rails14, which are arranged along the lateral edges of the roof opening7and run in a longitudinal direction. A vehicular hoop16is movably arranged in the two guide rails14. A front edge of the window shade10(with respect to the forward travel direction of the vehicle) is fastened to the vehicular hoop16. Each end of the vehicular hoop16has a drive element18to drive the window shade10mounted to the vehicular hoop16. In the illustrated examples, a cable that is guided to resist tension and bending is used as the drive element18, and the cable is movably received in the guide rails14.

The drive elements18may each have textured (e.g., corrugated or toothed) outer surface that engages a gear wheel20, which is supported on the sunshade assembly11to be stationary and rotatable. The gear wheel20ensures that the two drive elements18move synchronously, such as when the window shade10is manually shifted with the vehicular hoop16in the guide rails14. The gear wheel20may also connect an electric motor (not shown) to the drive elements18so that the electric motor can displace the drive elements18in the guide rails14toward the front and to the rear.

Each guide rail14supports a rotatable tension wheel22in a stationary manner (FIGS. 3 and 4). The rotatable tension wheel22has a transport portion24and a drive pinion26. The drive pinion26has a gear that engages with its corresponding drive element18so that the drive pinion26will rotate when translation al shifting of the drive elements18rotates the gear28. The transport portion24of the tension wheel22has a plurality of regularly arranged, barb-like protrusions30provided on its circumference surface. The protrusions30engage openings31that are provided along the lateral edges of the window shade10. As a result, rotation of the tension wheel22caused by translation al movement of the drive element18will be converted to translation al movement of the window shade10.

The two tension wheels22define an imaginary dividing line that subdivides the window shade10in two distinct portions, namely a front portion10′ and a rear portion10″. The front and rear portions10′,10″ are defined with respect to a forward travel direction of the vehicle. The front portion10′ of the window shade10is held taut between the two tension wheels22and the vehicular hoop16, by the two drive elements18. During assembly of the sunshade assembly11, the position of the two drive elements18, and therefore the position of the vehicular hoop16, will be adjusted relative to the two tension wheels22so that the front portion10′ of the window shade10will have the desired tension.

In the embodiment shown inFIG. 3, the rear portion10″ of the window shade10is received in an accommodation space32. The accommodation space32is schematically represented inFIG. 3with dotted lines. The rear portion10″ of the window shade10is disposed in the accommodation space32loosely and folds in a relatively random fashion. When the window shade10is pushed backward, the material released from the tension wheels22will simply gather in the accommodation space32. When the window shade10is pulled forward, the window shade10is gripped by the tension wheels22and introduced into the guide rails14. One particular advantage with receiving the rear portion10″ of the window shade10in this manner is that the accommodation space32can be configured with almost any cross-sectional profile in the transverse direction. For example, the accommodation space32may have a cross-sectional profile with a slight curvature to provide a particularly large clearance underneath the sunshade assembly11.

The lateral edges of the window shade10may be reinforced, particularly around the openings31. As shown inFIG. 8, reinforcements60,62may be disposed in the areas of the window shade10that contact the transport position24. In this way, the window shade10can be held taut in a transverse direction as well as in the longitudinal direction.

Note that the transport portion24of the tension wheels22may be formed to have a substantially flat circumference surface instead of having the protrusions30, as shown inFIG. 8. In this embodiment, the circumference surface of the transport portion24frictionally engages the corresponding lateral edge of the window shade10to move the window shade10.

FIG. 5illustrates a detail of a variation of the embodiment described above. Unlike in the first embodiment, the rear portion10″ of the window shade10in the embodiment shown inFIG. 5is wound in a controlled fashion rather than being loosely and randomly received in the accommodation space32. As shown inFIG. 5, the rear portion10″ of the window shade10is wound on two winding bodies40that are mounted on the guide rails14to lie opposite each other.

In the illustrated example, the winding bodies40are rotatable on a bearing boss42mounted to the guide rail14. A spiral winding spring44is arranged between each bearing boss42and each winding body40, and a biasing force of each winding spring44acts upon its corresponding winding body40in a selected wind-up direction. A rear edge of the rear portion10″ of the window shade10is fastened to the two winding bodies40in any appropriate known manner.

When the window shade10is pushed back, the rear portion10″ of the window shade10is released by the tension wheels22and is automatically wound up on the winding bodies40by the biasing force of the winding springs44. Because the two winding bodies40are disposed only at the lateral edges of the window shade10, the coil formed by the window shade10when it is wound on the winding bodies40is hollow inside, making it flexible. Thus, the coiled window shade10can be supported by any suitable guiding element (not shown) to provide a particularly large clearance underneath the sunshade assembly11.

FIG. 6is a schematic illustrating the sunshade assembly according to another embodiment of the invention. In this embodiment, the rear portion10″ of the window shade10is not received behind the tension wheels22. Instead, the rear portion10″ is wound directly on the two tension wheels22. To do this, the rear edge of the window shade10is fastened directly to the transport portion24of each of the tension wheels22. When the tension wheels22are rotated by shifting the drive elements18, the window shade10is wound or unwound corresponding to the direction of rotation. Also in this case, the vehicular hoop16and the drive elements18holds the front portion10′ of the window shade10taut.

However, as the diameter of the coil formed on the tension wheels22by the window shade10changes as a function of the amount of the window shade material wound thereon, the length of the wound or unwound window shade10will also change for every rotational angle of the tension wheels22. Thus, in the case where the window shade10is pushed almost completely to the rear and with a correspondingly thick coil, a predetermined shifting of the drive elements18will result in that a larger length of window shade material that is wound up or unwound, as compared to when the window shade is almost entirely pushed to the front with a correspondingly thinner coil. In other words, the shifting speed of the front portion10′, and consequently the shifting speed of the vehicular hoop16, varies during shifting the window shade10, assuming a constant shifting speed of the drive elements18.

To compensate for the varying shifting speeds, a length balancing element, such as a pressure spring50, may be included in the sunshade assembly11. The pressure spring50is arranged between the drive elements18and the vehicular hoop16and pre-tensions the rear portion10″ of the window shade10. At the same time, the pressure spring50takes up the relative movement between the drive elements18and the vehicular hoop16during shifting of the window shade10.

FIG. 7illustrates a variation of the embodiment shown inFIG. 6. In this embodiment, a spiral spring52acts as the length balancing element. The spiral spring52is effective between the drive pinion26of the tension wheel22and the transport portion24. The spiral spring52provides the necessary pretensions of the front portion10′ of the window shade10and also compensates for the relative movement between the transport portion24and the drive pinions26that arises during shifting of the window shade10. Shifting may occur because the transport portion24is coupled with the drive elements18through the window shade10and the vehicular hoop16while the drive pinions26are directly coupled with the drive elements18.

It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby.