GB2442233A - Sunblind with flexible web which may be bent to increase its curvature - Google Patents

Abstract

A sunblind system 100 comprises a flexible web 38 that may be extended from a stored condition into a deployed condition, and a bending device to bend the deployed web in a plane transverse to the direction of extension, such that at least a portion of the web has increased curvature, in said plane, in the deployed condition than in the stored condition. One or more ribs 118 may extend transversely to the direction of extension to support the web. The ribs may run relative to tracks 106 extending in the direction of extension, the tracks converging to bend the ribs as the web is extended. Alternatively, the bending device may be a cam (154, Fig. 19), geared drive (160, Fig. 20), piston (166, Fig. 21), solenoid (167, Fig. 23), or ramp element (170, Fig. 24) which acts between the track and the end of the rib. Further alternatively, the rib may comprise piezoelectric material or memory material which bends when subjected to changing voltage or temperature (Fig. 25). The web may be adapted to bend in a predetermined direction in response to the bending device. Also disclosed is a method of deploying such a sunblind.

Description

I

SUNBLIND SYSTEMS AND METHODS OF OPERATION

This invention relates to sunblind systems and particularly, but not exclusively, to a sunbljnd for use in a vehicle, including methods of operating the sunblind.

Sunbljnds are used to reduce solar heating of a vehicle cabin space by blocking sunlight passing through windows or sunroofs of the vehicle. Solar heating occurs when infra red (IR) radiation in the sunlight heats interior surfaces of the vehicle cabin, which surfaces then radiate and convect heat within the cabin space.

Without ongoing cooling, the heat emitted from the interior surfaces increases the cabin temperature above the ambient exterior temperature, often resulting in uncomfortably high temperatures for passengers of the vehicle.

Glass sunroofs have become a desired and marketable feature on vehicles such as cars. A glass sunroof brings more light into the vehicle, creating a spacious and pleasant ambience in the cabin. A glass sunroof also has the advantage of allowing a clear view of the sky even when the sunroof is closed.

Nowadays, automotive manufacturers compete to design and produce vehicles with larger areas of glass to maximise all-round visibility and to enhance the benefits to ambience mentioned above. To achieve this, vehicles are being produced with much of their roof being generally of glass or other transparent materials.

Various means are available for blocking light transmission through a sunroof or window. For example, it is common for areas of glass to include masking or tinting to reduce the transmission of sunlight into the cabin space. Masking or tinting has the disadvantage that it compromises the desirable spacious and pleasant cabin ambience by obscuring the natural light.

A well-known alternative to masks or tints is a sunblind which is extended across a sunroof or window to block Out sunlight. Without masking or tinting, the sunblind can be retracted allowing natural light to create a spacious and pleasant cabin ambience.

To illustrate known sunblind systems, reference will now be made to Figures 1 to 6 of the accompanying drawings. In those drawings: Figure 1 is a perspective view of the interior of a vehicle roof fitted with a sunblind comprising a single rigid panel; Figure 2 is a side elevation view of a roller blind installed in a vehicle, the vehicle being shown in longitudinal cross section with respect to the centre line of the vehicle; Figure 3 is an enlarged detail view of the roller blind of Figure 2 in transverse cross section; Figure 4 is a perspective view of a lamella system in an open condition; Figure 5 is a side elevation cross section view of a lamella system installed in a vehicle, the vehicle being shown in longitudinal cross section with respect to the centre line of the vehicle; and Figure 6 is a partial plan view of a vehicle roof illustrating the difference in shape between the sunblind track and the curved, tapering shape of the vehicle roof.

Figures 1 to 6 show that sunblinds come in various forms depending on their application. In its simplest form as shown in Figure 1, a sunblind 30 is implemented by a single generally rigid oblong panel 32. The panel 32 is typically arranged to slide under a transparent aperture 34 of a glass roof panel 36 to block S sunlight and to slide clear of the aperture 34 when it is desired to admit sunlight.

Single rigid sunblind panels 32 are limited to relatively small glass roof apertures 34 because the maximum aperture size of the glass roof 36 is restricted, by packaging limitations, to approximately half the length of the vehicle roof.

An alternative to a rigid panel sunblind is a roller blind comprising a retractable web of flexible sheet material such as fabric. This is shown in Figures 2 and 3.

Unlike a single rigid panel, a roller blind can be used to span a large glass roof aperture that may extend over most of the length of a vehicle roof. A roller blind is often used by an automotive manufacturer because of its simple design which comprises a relatively small number of light and inexpensive components.

Moreover the packaging volume required to install a roller blind into a vehicle is small and therefore does not unduly compromise the passenger cabin space when in the retracted condition. Roller blinds are particularly advantageous in glass roof applications since their reduction in packaging space allows a greater transparent aperture.

Unfortunately, when extended, a roller blind can significantly reduce headroom available to passengers of a vehicle. This is because vehicle roofs are not generally flat: the styling of the vehicle usually dictates that they are convex in external shape. That convexity, which translates into concavity when viewed from within the vehicle, maximises headroom and helps to create a spacious feeling within the cabin. In contrast, the web of flexible sheet material of an extended roller blind is generally flat, at least in a direction transverse to the direction of extension or retraction. /

Looking in more detail at Figure 2 of the drawings, a sunblind in the form of a roller blind is shown installed in a vehicle. A web 38 of flexible sheet material is shown in an unfurled position beneath a transparent aperture of a glass roof 40.

The material extends from a roller blind mechanism located beneath an opaque roof portion 44 to the rear of the vehicle roof. This opaque portion 44 obscures the roller blind mechanism 42 and any associated ancillaries from view. The opaque area may comprise a metal portion 46 of the vehicle roof or alternatively may be an extension of the glass roof 40 that includes additional masking or tinting.

Referring to Figure 3, flexible sheet material used in roller blinds has a tendency to sag. Consequently, the flexible sheet material of the roller blind can be seen in Figure 3 resting on a transverse support rib 48 whose ends 50 (only one of which is shown) are each slidably received in a respective channel 52 incorporated within a track 54. A plurality of support ribs 48 are incorporated within the material, evenly distributed along the length of the web 38 to provide adequate support.

These ribs 48 extend beyond the sides of the web 38 and their ends 50 rest either directly in the tracks 54 or are carried by a carriage (not shown) that moves along the tracks.

The tracks 54 provide for movement of the web 38 of flexible sheet material as it unfuris from the roller blind mechanism 42 towards the front of the vehicle, and as the web retracts. Each track 54 is positioned parallel and adjacent to a respective side of the oblong web 38. To guide the web 38, a primary support rib 48 is incorporated within the leading edge of the web. Motors, cables and controls are used to move the primary support rib 48, pushing or pulling it away from the roller and hence extending the blind. Biasing means are associated with the roller 42 for pulling the web 38 towards the retracted position, thus causing the blind to close when desired and, meanwhile, maintaining tension in the web when unfurled.

The front-to-rear shape of the roller blind is defined by the longitudinal path of the tracks 54 as shown in Figure 2. The tracks 54 follow the longitudinal curvature of the vehicle roof, which imparts longitudinal curvature to the web 38. Nevertheless, between the tracks 54, in a transverse direction, the web is flat as shown in Figure 3. The result is that if a cross section is taken transversely through the roof, the roof defines an arc and the roller blind approximates to a chord between the ends of the arc. The area between the arc of the roof and the chord of the roller blind is effectively lost usable volume of the cabin space. The reduction of cabin volume when the roller blind is extended reduces headroom and gives rise to a claustrophobic feeling for the passengers. A headroom arc 58 used for ergonomic measurement by computer-aided design is included in Figure 3 to show the extent to which headroom is limited by the roller blind.

Figures 4 and 5 show lamella systems, which are a known alternative to roller blinds. A lamella system 60 comprises a number of rigid panels 62 such as slats that are cooperable and arrangeable to form a sunblind when extended beneath a glass roof aperture. Each lamella 62 is individually formed so that in their extended positions the lamellae follow the curvature of the vehicle roof, thus mitigating the headroom problem associated with the use of roller blinds. A more spacious feeling is maintained for the passengers when the Iamellae are advanced to form a sunshade.

Figure 4 shows a lamella module typically used in an automotive application. In this application, the lamellae 62 define a retractable sunroof rather than a sunblind, although the principle of operation is the same. The module comprises a plurality of lamellae 62 arranged in an oblong frame 64 whose long sides define longitudinal tracks 66.

Each lamella 62 is formed from a substantially rigid and self-supporting material.

The lamella 62 is shaped with complementary formations along forward and rearward edges so that in the closed condition each lamella cooperates with and connects to the adjacent lamella or lamellae. On their side edges, lamellae 62 cooperate with and connect to the frame 64.

The frame 64 in which the!amellae 62 are mounted holds a mechanism used to open and close the lamella module. The mechanism uses a series of cables and motors (not shown) to move each lamella 62 backwards and forwards along the track 66 and to tilt them as required. In the open position, each lamella is slid towards the rear of the vehicle roof where the lamellae 62 are stored in a stack 68 on top of one another.

Although lamellae 62 are advantageous in mitigating the reduction of headroom suffered by roller blinds, lamellae have significant disadvantages of their own. In particular, when stored, the stack 68 occupies significantly more of the interior space than a comparable stored roller blind.

Figure 5 illustrates the volume that a stack 68 of stored lamellae 62 occupies when retracted. Comparing back to Figure 2, it can be seen that the transparent aperture of the glass roof is reduced because the opaque area 44 of the roof is increased to cover the stored lamellae 62 and their ancillaries.

Whereas a roller blind requires a storage volume defined by the roller and the material wrapped around the roller, each lamella 62 has a significant thickness to which must be added the gaps left between the lamellae for clearance. In addition to the material thickness, of say 10mm, a gap of approximately 5mm is required between each lamella 62 so that, in a stored condition, lamellae do not interfere with each other, causing damage or rattling. The gaps are also necessary so that the lamellae 62 can slide past each other.

For a large sunroof, a lamella system will require either a small number of large lamellae or a large number of small lamellae. If the former, the transparent aperture of the sunroof will be reduced. If the latter, the height of the stack of stored lamellae will be excessive.

By way of example, a glass sunroof with a front-to-rear aperture opening of 180cm may require three large lamellae, each 60cm in front-to-rear length, to cover the aperture when closed, or alternatively six smaller lamellae only 30 cm in front-to-rear length. In the first instance, the large lamellae will require at least 60 cm of front-to-rear storage space and at least 40mm of vertical storage space allowing for the two 5mm gaps. As a result, the front-to-rear length of the storage space limits the maximum transparent aperture size of the sunroof. In the second instance, the short Iamellae will require at least 30cm front-to-rear storage space but at least 85mm of vertical storage space allowing for six lamellae and five gaps.

This reduces the passenger headroom available inside the vehicle cabin.

Whilst the height of the stack 68 of lamellae 62 may be excessive even if the lamellae are flat, the problem becomes even more acute if the lamellae are of arcuate cross section to suit the internal curvature of the roof. This means that the thickness of each lamella is increased by the degree of curvature.

In addition to the problems encountered by the reduction of cabin space and sunroof aperture caused by the vertical storage of the lamellae, lamella systems are more costly than roller blind systems. The increased costs are associated with the additional material required to form the lamella, the increased complexity of the mechanism and the unique tooling required for each lamella. Moreover, lamella systems incur a high development cost. Roller blinds, on the other hand, have a lower component count and use more established technology. A lainella system can cost five times more than a comparable roller blind system.

Figure 6 shows a problem common to both roller blind and lamella systems. The longitudinal tracks 66 along which the web 38 or lamellae 62 are guided are parallel. However, in plan view, the roof of a vehicle is rarely parallel-sided: more often, as shown, the roof tapers rearwardly in plan. This means that the effective width of the transparent aperture 40 is limited to that of the narrow rear of the roof.

As a result, the transparent aperture 40 cannot fully extend across the width of the roof because otherwise the tracks and associated ancillaries would be visible and the sunblind would not cover the full width of the transparent aperture. It is therefore necessary to mask the sides of the glass roof panel 36, or to restrict the glass roof panel to a parallel-sided, usually oblong shape. Both are to the detriment of transparent roof area and to vehicle styling.

It is against this background that the present invention has been made. This invention results from efforts to overcome the problems of known roller blinds and lamellae sunblind systems. Other aims of the invention will be apparent from the

following description.

From one aspect, the invention resides in a sunblind system comprising: a flexible web that may be moved from a stored condition into a deployed condition; and bending means to bend the deployed web in a plane transverse to the direction of extension, such that at least a portion of the web has increased curvature, in said plane, in the deployed condition than in the stored condition.

The invention advantageously increases actual and perceived headroom and creates a spacious feeling within a vehicle cabin. To do so, the invention advantageously displaces the web upwards, forming a curved shape that complements the shape of the vehicle roof. The invention does so by various means such as converging tracks, adaptable support ribs, adaptable web material, additional mechanisms or a combination thereof.

The web may be collapsible into a compact form in the stored condition, for example by being furled in the stored condition.

The web may be supported by one or more ribs extending transverse to the direction of extension. The or each rib may be integral with the web and may run relative to a track extending in the direction of extension. For example, a carriage running along the track may support an end of a rib and the rib may be hingedly connected to the carriage. In that case, the hinge may be constrained to pivot about an axis parallel to the part of the track holding that carriage. This resists twisting of the rib.

The rib and/or the web may be adapted to bend in a predetermined direction in response to the bending means. For example, the web or the rib may be stiffer in bending in one direction than in an opposed direction. This may be achieved by forming the web or the rib of first and second materials of mutually different stiffness, or by providing formations on one side of the web or the rib that increase or reduce stiffness in comparison with the other side.

The bending means may be carried by the carriage. For example, the bending means may be an actuator that acts between the track and the end of the rib. The actuator may, for example, be a cam, a piston, a solenoid, a geared drive or a ramp element as will be described. The actuator may be responsive to movement of the web in the direction of extension.

In another approach, the bending means may comprise converging tracks along which the web moves in the direction of extension to impart compressive forces inwardly across the web. The tracks may have at least one converging portion and at least one parallel portion. For example if the web is in the stored condition when at a storage location, the parallel portion of the tracks may be adjacent the storage location to ease movement of the web in that region. It is also possible for the tracks to have at least one converging portion and at least one diverging portion.

In some arrangements, the bending means may be intrinsic to the web or to a rib supporting the web. For example, the web or the rib may comprise piezoelectric material or memory material that, when subjected to changing temperature or exposed to sufficient voltage, bends in a plane transverse to the direction of extension. It is also possible for the web or the rib to be pre-formed to bend, when the web is deployed, in a plane transverse to the direction of extension.

The web may also bend in a plane parallel to the direction of extension, for example during extension.

The web may be self-supportingly rigid. For example, the web may be a panel, such as one of a plurality of lamellae.

The invention extends to a vehicle sunblind system comprising: -a flexible web that may be deployed inside the cabin of a vehicle across a window or sunroof that is concave-curved when viewed from within the cabin; and bending means to bend the deployed web in a plane transverse to the direction of extension, to complement the curvature of the window or sunroof.

The invention also encompasses a vehicle having the sunblind system of the invention.

Another aspect of the invention resides in a method of deploying a sunblind, comprising: moving a flexible web from a stored condition into a deployed condition in a direction of extension; and bending the deployed web in a plane transverse to the direction of extension, to complement the shape of a window or roof light with which the blind is associated.

The principle of the invention can be extended beyond sunblind systems for use with glazed roofs and windows. Specifically, the invention may be applied to vehicles having convertible or retractable roofs and can bring similar advantages to such applications in terms of actual and perceived spaciousness. An example of a convertible or retractable vehicle roof system comprises a flexible roof cover that may furl onto a roller or be folded into a concertina arrangement. It is also possible for a convertible or retractable roof to comprise semi-rigid panels or to be in the form of a folding hard-top.

Thus, in a broad sense, the invention extends to a vehicle roof system comprising a flexible web that may be extended from a stored, open condition into a deployed, closed condition; and bending means to bend the web in a plane transverse to the direction of extension, such that at least a portion of the web has increased curvature, in said plane, in the deployed condition than in the stored condition.

This aspect of the invention may also be expressed as a method of deploying a vehicle roof, comprising moving a flexible roof web from a stored, open condition into a deployed, closed condition in a direction of extension; and bending the web in a plane transverse to the direction of extension, to increase the headroom available under the roof when the roof is closed. This aspect extends to vehicles having the roof system or operating according to the method as defined.

Reference has already been made to Figures 1 to 6 of the accompanying drawings which illustrate sunblinds known to those skilled in the art. In order that the invention may be more readily understood, reference will now be made, by way of example, to the remainder of the drawings in which: Figure 7 is a perspective view of a roller blind in an unfurled condition and including indications of cross-section VIlI-Vill, vehicle orientation FR and X-Y-Z orientation; Figure 8 is an enlarged view of the cross section VIlI-Vill showing a detailed view of the roller blind of Figure 7 in a vehicle installation; Figure 9 is a plan view of a first embodiment of the invention showing tracks curving inwards with respect to the width of the roller of the roller blind, further including indications of cross-section Vill-VIlI as above and a modified cross section X-X where the tracks are closer to each other and hence further from the sides of the vehicle; Figure 10 is an enlarged view of the cross section X-X showing a detailed view of the roller blind of Figure 9 in a vehicle installation; Figure 11 is an enlarged detail view of the roller blind of Figure 9 in transverse cross section, the view corresponding to Figure 3 to show the increased headroom provided by the invention; Figure 12 is an enlarged cross-sectional view showing a variant of the embodiment of Figures 9, 10 and 11; Figure 13 is a plan view of the roller blind of Figure 9 incorporating a transverse support rib with arrows indicating how the support rib tends to twist; Figure 14 is a perspective view of the support rib of Figure 13 hingedly attached to a carriage; Figure 15 is a cross-sectional view showing a carriage drive mechanism using a cable in a channel along which the carriage runs; Figure 16 is a perspective view of the carriage drive means of Figure 15, showing its interaction with the carriage of Figure 14; Figure 17 is a cross section of a support rib comprising two materials to determine the direction of deflection in use; Figure 18 is a cross section of a support rib having formations shaped to determine the direction of deflection in use; Figures 1 9a and 1 9b are enlarged cross-sectional views of an alternative embodiment of the invention including a cam to deflect the rib; Figure 1 9c is a plan view of the embodiment of Figures 1 9a and I 9b; Figures 20a and 20b are enlarged cross-sectional views of another embodiment of the invention including a worm gear to deflect the rib; Figures 21a and 21b are enlarged cross-sectional views of another alternative embodiment of the invention including a ram to deflect the rib; Figure 22 is an enlarged cross-sectional view of another embodiment of the invention including a pneumatic piston to deflect the rib; Figure 23 is an enlarged cross-sectional view of another embodiment of the invention including a solenoid to deflect the rib; Figures 24a and 24b are plan views of an alternative embodiment of the invention including a wedge to deflect a series of parallel ribs; and Figures 25a and 25b are cross-sectional views of a support rib to which a potential difference is applied via the track to deflect the rib as shown in Figure 25b.

Referring to Figure 7 of the drawings, a roller blind 100 is shown in an extended or unfurled condition. The front of the vehicle is indicated by arrow FR'. A roller 102 is located at the rear so the web 38 of the blind 100 extends forwardly and retracts rearwardly. The axes X, Y and Z are shown indicating the orientation of the roller blind 100. Respectively, the X, Y and Z axes represent a longitudinal vehicle direction, transverse vehicle direction and height. A section, VIlI-Vill is marked to one side of the unfurled blind.

Section VIJI-VilI is shown in Figure 8. This illustrates how roller blind components are secured to a body portion of the vehicle (not shown) by a body support bracket 104. A track 106 is fixed to the body support bracket by a bolt 108 and comprises an inwardly-facing C-section channel 110 in which a foot 112 of a carriage 114 is received, the carriage being attached to an end 116 of a resilient support rib 118 as will be described.

In practice, the web 38 of the roller blind, not shown in Figure 8, is supported by a series of parallel ribs 118 to prevent the web sagging downwards into the cabin space. Each rib 118 has two carriages 114, one at each end. Each rib is slightly longer than the width of the web to define the protruding end portions 116. The end portions 116 extend beyond the web 38 to be received in respective carriages 114. Thus, in use, a plurality of the carriages 114 shown in Figure 8 are spaced along each track 106 extending along a respective side of the vehicle roof.

Whilst Figure 7 shows the web 38 of the roller blind in a generally planar configuration, the invention resides in various means to impart transverse curvature to the web as will be described. That curvature may be imparted as a consequence of extension or unfurling of the web; it may also, or alternatively, be imparted after extension or unfurling of the web.

The embodiment shown in Figure 9 is an example of how curvature may be imparted as a consequence of extension or unfurling of the web 38. Figure 9 is a plan view of a roller blind system 120 having a pair of tracks 106 shaped to reduce the span between the tracks moving away from the roller of the roller blind mechanism. Sides 124 of the vehicle roof are shown to indicate the curvature of the tracks 106 in relation to the vehicle roof.

Two sections are indicated through side portions of the web and the adjacent track: section V1II-VIII corresponds to that shown in Figure 8 and is taken close to the roller where the span between the tracks 106 is greatest; conversely, section X-X is taken further from the roller where the span is at a minimum.

Section X-X is shown in Figure 10. Here, the body support bracket 104 is extended so that the track 106 is further in from the side 124 of the roof than in section VJll-VTH. As the span between the tracks 106 reduces as a consequence, the support rib 118 is deflected upwards to take an arcuate shape. Specifically, as the web 38 is unfurled, the narrowing of the span applies an inward compressive force F upon the ends 116 of each rib 118, via the carriages 114 of that rib 118, upwardly displacing a centre portion 126 of the rib. The upwards displacement of the centre portions 126 of the ribs 118 imparts a corresponding curvature to the web 38 supported by the ribs, thus increasing the headroom within the cabin. The degree of upward displacement of the centre portion 126 is determined by the reduction in the span.

To appreciate the improvement in headroom gained within the vehicle cabin, Figure 11 shows the position of the web 38 by virtue of the invention, that position being shown by a solid line. For comparison, the web position of an existing roller blind is shown by a dashed line 128. Figures 3 and 11 may be compared and contrasted in this respect.

Figure 12 illustrates a variant of the invention that encourages the support rib 118 to form an upwardly-deflected web 38 shape. The C-section channel 110 in which the carriage 114 is received faces slightly upwardly by an angle 0 with respect to the horizontal. The angle 0 may increase as the span narrows, thus facilitating the increased upward displacement of the centre portion 126 at that point.

The tracks 106 shown in Figure 9 have end sections in which the tracks are substantially parallel, joined by intermediate sections in which the tracks converge. The parallel end sections closest to the roller of the roller blind system 120 help to feed the web smoothly off the roller during extension and on to the roller during retraction. The parallel end sections further from the roller maintain a desired degree of curvature in the web and hence constant headroom in the forward part of the vehicle cabin.

Other track configurations are possible: for example, the tracks may simply converge in straight lines whose projections intersect ahead of the vehicle. It is also possible for the tracks to be parallel and for other means to be used to impart upward curvature to the web. Such means will now be described with reference to the embodiments of the invention that follow.

As shown in Figure 13, the support ribs 118 may be inclined to twist inuse of the blind. Consequently, as shown in Figure 14, the support rib 118 is preferably broadened in a longitudinal direction to define a strip-like profile. Moreoever, the rib 118 is preferably linked to the carriage 114 via a hinge 130 whose pivot axis is parallel to the part of the track 106 with which the carriage is engaged. For this purpose, a hinge pin 132 passes through the end of the support rib 116 protruding from the side of the web and connects at each end to holes 134 in arms 136 of a U-shaped part of the carriage 114. A foot 112 extending outwardly from the base of the U-shaped part engages in the adjacent track.

When inward compressive force F is applied to the support rib 118 via the carriage 114, the centre portion of the rib 126 is constrained by the hinge 130 to deflect only along the Z axis. The hinge has the effect of stabilising the rib by resisting twisting moments.

Figure 15 shows a modified track 138 in which a cable 140 runs to move a carriage 114 of at least one of the ribs 118. Specifically, the cable runs in a part-circular profile 142 at the base of the C-section channel 110 defining the track.

Figure 16 shows a U-shaped retainer 144 attached to the cable 140, with the arms of the U being dimensioned to embrace the aforementioned foot 112 of the carriage 114. Thus, as the retainer 144 moves with the cable 140, the retainer applies force to the carriage 114 via the foot 112 to move the carriage along the track.

Preferably, the cable acts on the rib furthest from the roller of the roller blind to unfurl the web from the roller during extension. Furling of the web during retraction is preferably driven by bias means turning the roller and drawing back the web for furling about the roller, although the cable must also move to permit retraction of the web.

The invention contemplates other optional means for ensuring that the ribs deflect upwardly rather than downwardly under inward compressive forces. For example, in one embodiment, the rib 118 comprises two materials, each of a different stiffness and bonded one on top of the other. Figure 17 is a cross-section of a dual-material rib wherein an upper material 146 is stiffer (for example denser) than a lower material 148. As compressive force is applied to the ends of the rib, the centre portion of the rib is displaced upwardly because the stiffer upper material 146 is better able to resist compression than the more flexible lower material 148.

Consequently, the lower material goes into compression on the inside of the arc and the upper material goes into tension on the outside of the arc.

Figure 18 shows how a rib 150 may be shaped to ensure that the centre portion 126 deflects upwardly under compression. In this embodiment, formations 152 in the form of an array of parallel grooves defines a saw-tooth pattern in the underside of the rib along its length. This imparts differential stiffness to the rib to ensure upward displacement of the centre portion 126 for the same reason as in the embodiment of Figure 17. Other shapes or formations 152 may be applied to the support rib to achieve the same objective.

There are various ways to apply compressive forces to the ends of a rib. One way has already been described: this is to move the rib between converging tracks.

Another way is to employ an intermediate actuator between a track and the associated end of the rib, the actuator being extensible to apply inward compressive force to the rib while reacting against the track. Such actuators may be used to impart curvature to ribs even where tracks are parallel although they may also be used with non-parallel tracks if desired.

Figure 19a and 1 9b are cross sections of an actuator shown respectively in its inactive and active states. In this embodiment, when in the active position, the actuator applies an inward compressive force to the rib using a cam 154. The cam is ovate and pivots around a pin 156 fixed to a base 158 of the carriage 114. The carriage embraces an end 116 of the rib 118, locating the rib 118 for sliding inward and outward movement with respect to the carriage while transmitting side forces to the rib for extension and, optionally, retraction of the blind. A foot 112 of the carriage fits slidingly within the C-section channel 110 of the track 106.

The cam 154 shown by the solid line in the plan view of Figure 19c represents the cross-section shown in Figure 1 9a in which the cam is retracted. In this condition, the end 116 of the rib 118 rests against the narrowest part of the cam, whereby the cam 154 applies no inward force to the end of the rib. Consequently, the centre portion of the rib 126 is not deflected. Conversely, the dashed line in Figure 1 9c represents the cam 154 in an extended position. When extended, the cam 154 is turned through 90 so that the end 116 of the rib 118 rests against the widest point of the cam. In this position, the cam 154 presses against the end 116 of the rib 118, which slides inwardly with respect to the carriage 114. This deflects the centre portion of the rib 118 upwardly as already described.

The cam 154 may be turned using an electric motor (not shown) associated with the carriage 114 or by engagement with drive formations associated with the track 106, movement of the cam being driven by movement of the carriage along the track as the roller blind is extended and retracted. For example, a toothed rack (not shown) extending along the track 106 may engage with pinion fonnations on the cam 154 as the carriage 114 that carries the cam moves along the track.

Another way of applying compressive force to the ends of a rib 116 is shown in Figures 20a and 20b, again in its inactive and active states respectively. The compressive force F is generated by the movement of a worm gear 160 supported by the carriage 114. Specifically, a foot 112 of the carriage at one end of the worm gear 160 slides along a C-section channel 110 of a track 106. The carriage is hinged to the rib 118 at the other end of the worm gear 160. The worm gear 160 is engaged with a toothed extension 162 of the track 106 that lies parallel to the central rotational axis of the worm gear.

Figure 20a shows the worm gear 160 in an outward position, close to the C-section channel 110 of the track 106. Here, the worm gear 160 transmits no compressive force to the rib 118. Conversely, Figure 20b shows the worm gear in an inward position having turned by virtue of being moved relative to the toothed extension 162 of the track 106, as happens upon unfurling the web of the roller blind. This moves the worm gear inwardly away from the C-section channel 110 of the track 106, towards the centre of the vehicle, bearing against the end of the rib 116 to apply a compressive force that deflects the centre portion 126 of the rib upwardly as shown.

Another actuator arrangement, shown in Figures 21 a and 21 b, comprises a carriage 114 having a ram 164 acting between a foot 112 engaged with the track 106 and the end of a rib 116 hinged to a piston 166 of the ram. Figures 21a and 21b respectively show the movement of the piston 166 between a retracted state, in which no compressive force is transmitted to the rib 118, and an extended state in which compressive force is transmitted to the rib 118 to cause upward deflection of its centre portion 126. The ram 164 may, for example, employ hydraulic drive but Figure 22 shows a variant in which the piston may be driven pneumatically.

Alternatively Figure 23 shows how the piston of Figures 21a, 21b and 22 may be replaced by a solenoid 167.

Another way to generate the inward force necessary to deflect the ribs 118 is to move a common ramp element 168 such as an elongate wedge 170 through the carriages 114 of successive ribs, between the track 106 and the respective rib ends 116. Figures 24a and 24b show how a wedge 170 may be drawn, using a cable 172 and a motor 174, between the ends of the ribs and the adjacent track 106. The local thickness of the wedge 170 determines the extent to which the centre portion 126 of a rib 118 at that location is deflected. Consequently, by shaping the wedge, the inward force applied to the ends of the support ribs may be varied to tailor the curvature of the ribs.

Figure 24a is a partial plan view showing the support ribs 118 of the roller blind in an unfurled condition. The end of each rib 126 can be seen displaced inwardly from the outside edge of the track 106 by the wedge 170, hence imparting upward curvature to the ribs although this curvature cannot be seen in plan view. Figure 24b shows the position of the rib ends 126 when approximately three quarters of the roller blind is unfurled. In this instance, the wedge 170 has not been fully drawn between the ribs and the track. The web adjacent the roller 102 of the roller blind is flat because the wedge has not yet acted upon the rib at that location, resulting in no compressive force against the end of the rib and thus no upward displacement of its centre portion 126. On the other hand, where a wedge has been drawn between the ends of the other ribs and the track, those ribs have been displaced inwardly to impart upward deflection to the web at locations further from the roller.

Referring finally to Figures 25a and 25b, these show how a potential difference 176 may be applied via the track 106 to a rib 118 to deflect the rib, as shown in Figure 25b. The applied voltage generates mechanical forces within the rib by, for example, activating piezoelectric crystals in the rib or otherwise employing memory characteristics of the rib material. This generates a force within the material causing the centre portion 126 of the support rib to deflect upwards.

The embodiment shown in Figures 25a and 25b shows that deflection of a rib 118 does not necessarily require the application of external compressive force to the ends of the rib 116: it is possible for the rib to draw itself into an upwardly deflected shape. Indeed, a rib may do so even without the provision of an external stimulus such as an electric current: it is possible for a rib to be pre-formed in an upwardly curved shape and to be straightened under tension by having its ends pulled outwardly by outwardly-acting actuators on the carriages, or by diverging tracks.

Many variations are possible within the inventive concept. For example, it is possible to drive the worm gear differently, for example omitting the toothed extension of the track and instead providing a similar feature on the carriage. In that case, a separate drive means such as a motor may be carried by the carriage to turn the worm gear. It would also be possible to dispense with the worm gear and instead to use a motor to cause relative movement between a threaded shaft on the carriage engaged with a nut or other internally-threaded element, whereby the nut moves along the shaft to apply deflecting pressure to the end of a rib.

Where a wedge is employed to generate inward compressive force upon a rib, it is not essential for the wedge to move relative to the track: it is possible for the wedge to be fixed in relation to the track and for relative movement between the carriage and the wedge to generate the desired inward compressive force.

Whilst the invention has been described above in the context of a roller blind, it is possible within the inventive concept to apply the principles of the invention to a sunblind system comprising one or more panels of self-supporting rigidity. For example, one or more lamellae may be deflected into an upwardly-curved shape when deployed but into a flatter shape for more compact storage when retracted.

For this purpose, the term web' in this specification is to be taken to encompass panels that whilst self-supportingly rigid, also have the flexibility necessary to be (IPflPCtPAI It is not essential that a web must always be supported by a rib and that the rib is bent to bend the web: it is also possible for the web itself to be bent, either by external bending means such as actuators or by internal bending means such as intrinsic memory properties of the web material.

The invention can be applied to any light-transmitting aperture: not just a vehicle sunroof but also vehicle windows, for example.

In view of these and other variants within the inventive concept, reference should be made to the appended claims rather than the foregoing specific description in determining the inventive concept.

Claims (35)

1. A sunblind system comprising: a flexible web that may be moved from a stored condition into a deployed condition; and bending means to bend the deployed web in a plane transverse to the direction of extension, such that at least a portion of the web has increased curvature, in said plane, in the deployed condition than in the stored condition.

2. The system of Claim 1, wherein the web is collapsible into a compact form in the stored condition.

3. The system of Claim 2, wherein the web may be furled in the stored condition.

4. The system of any preceding Claim, wherein the web is supported by one or more ribs extending transverse to the direction of extension.

5. The system of Claim 4, wherein the or each rib is integral with the web.

6. The system of Claim 4 or Claim 5, wherein the or each rib runs relative to a track extending in the direction of extension.

7. The system of Claim 6, wherein a carriage running along the track supports an end of a rib.

8. The system of Claim 7, wherein the rib is hingedly connected to the carriage.

9. The system of Claim 8, wherein the hinge is constrained to pivot about an axis parallel to the part of the track holding that carriage.

10. The system of any of Claims 4 to 9, wherein the rib is adapted to bend in a predetermined direction in response to the bending means.

11. The system of any preceding Claim, wherein the web is adapted to bend in a predetermined direction in response to the bending means.

12. The system of Claim 10 or Claim 11, wherein the web or the rib is stiffer in bending in one direction than in an opposed direction.

13. The system of Claim 12, wherein the web or the rib is of first and second materials of mutually different stiffness.

14. The system of Claim 12 or Claim 13, wherein the web or the rib has formations on one side that increase or reduce stiffness in comparison with the other side.

15. The system of any of Claims 7 to 14, wherein the bending means is carried by thc carriage.

16. The system of Claim 15, wherein the bending means is an actuator that acts between the track and the end of the rib.

17. The system of Claim 16, wherein the actuator is selected from a cam, a piston, a solenoid, a geared drive or a ramp element.

18. The system of Claim 16 or Claim 17, wherein the actuator is responsive to movement of the web in the direction of extension.

19. The system of any of Claims 1 to 14, wherein the bending means comprises converging tracks along which the web moves in the direction of extension to impart compressive forces inwardly across the web.

20. The system of Claim 19, wherein the tracks have at least one converging portion and at least one parallel portion.

21. The system of Claim 20, wherein the web is in the stored condition when at a storage location and wherein the parallel portion of the tracks is adjacent the storage location.

22. The system of any of Claims 19 to 21, wherein the tracks have at least one converging portion and at least one diverging portion.

23. The system of any of Claims I to 14, wherein the bending means is intrinsic to the web or to a rib supporting the web.

24. The system of Claim 23, wherein the web or the rib comprises piezoelectric material or memory material that, when subjected to changing temperature or exposed to voltage, bends in a plane transverse to the direction of extension.

25. The system of Claim 23 or Claim 24, wherein the web or the rib is pre-forrned to bend, when the web is deployed, in a plane transverse to the direction of extension.

26. The system of any preceding Claim, wherein the web bends in a plane parallel to the direction of extensjon.

27. The system of Claim 26, wherein the web bends in said plane during extension.

28. The system of any preceding Claim, wherein the web is self-supportingly rigid.

29. The system of Claim 28, wherein the web is a panel.

30. The system of Claim 29, wherein the panel is one of a plurality of lamellae.

31. A vehicle sunblind system comprising: a flexible web that may be deployed inside the cabin of a vehicle across a window or sunroof that is concave-curved when viewed from within the cabin; and bending means to bend the deployed web in a plane transverse to the direction of extension, to complement the curvature of the window or sunroof.

32. A vehicle having the sunblind system of any preceding Claim.

33. A method of deploying a sunblind, comprising: moving a flexible web from a stored condition into a deployed condition in a direction of extension; and bending the deployed web in a plane transverse to the direction of extension, to complement the shape of a window or roof light with which the blind is associated.

34. A sunblind system, substantially as hereinbefore described with reference to, or as illustrated in, any of Figures 7 to 25b of the accompanying drawings.

35. A method of deploying a sunb!ind, substantially as hereinbefore described with reference to, or as illustrated in, any of Figures 7 to 25b of the accompanying drawings.