Roller blind with a guide element

Abstract

 What is described is a roller blind comprising a cassette (2) for housing a winding roller (3), on to which a blind fabric (4) is wound, an aperture (7) being formed in the cassette for the passage of the fabric in the unwinding and winding of the latter, the aperture (7) being delimited by a pair of opposing edges (7a,7b) extending in the direction of longitudinal extension of the cassette (2), and a front strip (6) which has a pair of corresponding edges (6a,6b) running longitudinally and opposed to each other and which is fixed to an end (4a) of the fabric (4) transversely opposed to the roller (3), the strip being movable to close the aperture (7) in the cassette when the fabric (4) is wound on to the winding roller (3) in an inoperative condition. The blind comprises at least one guide element (10) fitted in the cassette (2) in a position such that it interferes with the strip (6) in the approach of the latter to the cassette, as a result of the winding of the fabric (4) on to the roller (3), in such a way as to guide the strip (6) in the closing of the aperture (7), with the longitudinal edges of the strip (6) and the cassette (2) which face each other being engaged with each other, in opposition to the flexural deformation of the strip.

Description

[0001] The present invention relates to a roller blind having the characteristics stated in the preamble to Claim 1, which is the principal claim.

[0002] The invention relates particularly, although not exclusively, to the specific technical field of roller blinds of the cassette type, in which the winding roller, the blind extension arms and any drive unit are housed in a cassette structure designed to be closed when the fabric is fully wound on to the winding roller, in the inoperative condition.

[0003] For this purpose, the cassette is made with a longitudinal aperture through which the fabric is unwound and extended by means of the arms. The blind fabric is also made with a terminal edge fastened to a front strip positioned parallel to the winding roller, in such a way that, when the fabric is unwound, the forced opening of the arms for extension (by means of springs or similar means) pushes the front strip away from the roller, thus extending the fabric through the aforesaid aperture. Conversely, after the fabric has been wound back on to the roller, the strip is brought towards the cassette until it is made to close the aperture, when the fabric has been fully wound on to the roller.

[0004] In these "cassette" blind applications, depending on the specific requirements, the fabric can have extensions of a certain length in the longitudinal direction, making it necessary to provide cassettes and front strips which are of corresponding length. A limitation encountered in these solutions is the fact that the strip tends to bend as a result of the longitudinal extension, showing flexural deformation, the maximum deflections occurring in the middle of the strip and interfering with its engagement with the cassette, since they prevent the longitudinal edges of the strip from being correctly superimposed on the facing edges of the aperture in corresponding positions, owing to the flexion of the front strip. The greater flexural deformation caused in the strip by comparison with that of the cassette is therefore such as to compromise the matching of the facing edges when the parts are engaged with each other for closing.

[0005] The fundamental problem of the present invention is that of providing a roller blind whose structural and functional design enables the limitations of the aforementioned prior art to be overcome.

[0006] The invention resolves this problem by means of a roller blind made in accordance with the following claims.

[0007] Further characteristics and advantages of the invention will be made clearer by the following detailed description of a preferred example of embodiment thereof, illustrated, for the purposes of guidance and without restrictive intent, in the attached drawings, in which:

• Figure 1 is a schematic perspective view of a roller blind made according to the invention;
• Figure 2 is a cross-sectional view, on an enlarged scale, of the roller blind of Figure 1;
• Figure 3 is a view corresponding to that of Figure 2 in a different operating condition;
• Figure 4 is a perspective view on an enlarged scale of a detail of the roller blind of the preceding figures.

[0008] With reference to the aforesaid figures, the number 1 indicates the whole of a sun blind of the roller type made according to the present invention. It comprises a cassette 2 in which a winding roller 3 is housed and rotatably supported, the roller being powered by means of a drive unit (not shown) and designed to receive a fabric 4 wound on to it. For extending the fabric, one or more pairs of extendable arms 5 are also provided, these arms being shown purely schematically in Figure 1 and each having one end hinged inside the cassette and an opposite second end hinged to a front strip 6 extending parallel to the longitudinal direction of extension of the cassette.

[0009] Each arm 5 is provided with two or more portions hinged together and pushed towards the extended position by springs or other similar return means of a conventional type (not shown), such as those typically provided in blinds with extendable arms.

[0010] In the cassette 2 there is formed an aperture 7 delimited by a pair of opposed edges 7a, 7b extending in the longitudinal direction of extension of the cassette, the said aperture allowing the passage of the fabric and the arms during the unwinding and winding of the said fabric.

[0011] The front strip 6 has a pair of longitudinal edges 6a, 6b running longitudinally and opposite each other. The strip 6 is also fixed to one edge of the free end 4a of the fabric, which is transversely opposed to the roller 3, and can also be moved so that it closes the aperture 7 of the cassette when the fabric is fully wound on to the winding roller 3, in the inoperative condition.

[0012] Consequently, when the strip 6 is moved to close the aperture 7, the fabric and the arms are housed in the cassette, and thus no component of the blind remains outside the cassette structure.

[0013] According to a principal characteristic of the invention, the blind 1 comprises a guide element, indicated as a whole by the number 10, fitted in the cassette, in such a position that it interferes with the strip 6 in the approach of the latter to the cassette as a result of the winding of the fabric on to the roller, as is clearly indicated in the remainder of the description.

[0014] The guide element comprises, in particular, a linkage 11, supported rotatably on the stationary structure of the cassette, in such a way that it can oscillate to a limited degree about an axis of oscillation X. More specifically, the linkage 11 is pivoted about the axis X in the form of a first-class lever, having a first and a second end, indicated by 11a and 11b respectively, positioned on opposite sides of the axis X.

[0015] Preferably, the linkage 11 is formed from a pair of plate-like bodies 12a, 12b, parallel and spaced apart, which are fixed together and supported oscillatably on the cassette 2 about a pin allowing free oscillation 12c coaxial with the axis X. At the first end 11a, between the bodies 12a, 12b, there is a rotatably supported idle roller 12d, whose axis of rotation Y parallel to the axis of oscillation X, and whose function will be explained below.

[0016] At the second end 11b, the linkage 11 comprises, in each of the bodies 12a, 12b, a first and a second appendage 13a, 13b, which can bear, respectively, on a first and a second bearing surface 14a, 14b of the cassette, thus forming elements limiting the oscillation of the linkage about the axis of oscillation X.

[0017] Consequently, the linkage 11, as shown in Figure 2, can oscillate to a limited degree between two angular positions, of which one is shown in solid lines and the other in broken lines in the aforesaid figure.

[0018] The front strip 6 is fixed to a plate element 15, fixed to it in a position facing the guide element 10 and capable of interacting with the latter. In the plate element 15 there is identified a first base portion 15a, used for fixing to the strip, by means of a screw 16 for example, and a second portion 15b, extending substantially at a right angle to the first portion towards the guide element. The internal area connecting the two portions faces the guide element and is shaped so as to interact by mutual contact with the roller 12d, in such a way that the linkage is made to oscillate by the plate, as a result of their mutual interference, and the plate, together with the strip, is in turn supported by the linkage during the oscillatory travel about the axis X.

[0019] In a normal operating condition, in which the fabric is in the unwound position, with the arms extended and with the strip at least partially moved away from the cassette, the linkage 11 is oscillated under its own weight into the position shown in broken lines in Figure 2, where the first appendage 13a bears on the bearing surface 14a.

[0020] From this condition, when the fabric is to be wound on to the roller by rotating the winding roller in the opposite direction, the front strip is made to approach the cassette by the return of the arms to the closed position. In this approach movement, the plate interferes with the roller 12d of the linkage, coming into mutual contact with the roller, with a corresponding degree of rolling. Thus, during the movement along the arc of oscillation of the linkage, the linkage supports the strip (since the lever arm remains constant during the oscillation) in its trajectory about the axis X, so as to guide the strip in its approach to the cassette with the opposing edges 6a, 6b facing the corresponding edges 7a, 7b of the aperture (Figure 3). This action of supporting the strip advantageously opposes the flexural deformation which is created in the strip by its weight and by its longitudinal extension, and which would prevent the correct superimposition of the longitudinal edges of the strip on the corresponding edges of the front aperture to correctly close the cassette.

[0021] Furthermore, owing to the fitting with a limited degree of oscillation, the linkage performs its function of supporting and guiding the strip, by projecting in the inoperative condition (corresponding to the linkage position shown in broken lines in the figure) to facilitate the engagement with the strip, but ceasing to project, as a result of its limited degree of oscillation, and thus remaining housed inside the cassette, in the closed position of the strip (corresponding to the linkage position shown in solid lines in the figure).

[0022] Furthermore, the guide element is preferably made to be positioned in the middle of the longitudinal extension of the strip (Figure 1), where the deflection due to flexural deformation is maximal, although clearly one or more such elements can be placed in different positions along the extension of the strip.

[0023] Thus, because of the guide element according to the invention, the deformation of the strip is opposed during the winding of the strip, the front strip being supported in its engagement with the cassette so as to enable the facing edges of the strip and the cassette to be correctly matched until the cassette is fully closed.

[0024] Thus the invention resolves the initial problem and provides the previously stated advantages over the known solutions.

Claims

1. Roller blind, comprising:

- a cassette (2) for housing a winding roller (3) on which a blind fabric is wound, an aperture (7) being formed in the cassette for the passage of the fabric during the unwinding and winding of the latter, the said aperture (7) being delimited by a pair of opposing edges (7a,7b) extending in the longitudinal direction of extension of the cassette (2); and

- a front strip (6) which has a pair of corresponding edges (6a,6b) running longitudinally and opposed to each other, and which is fixed to an end (4a) of the fabric (4) transversely opposed to the roller (3), the said strip being movable to close the said aperture (7) in the cassette when the fabric (4) is wound on to the winding roller (3) in the inoperative condition,

characterized in that it comprises at least one guide element (10) fitted in the cassette (2) in a position such that it interferes with the strip (6) in the approach of the latter to the cassette, as a result of the winding of the fabric (4) on to the roller (3), in such a way as to guide the strip (6) in the closing of the said aperture (7), with the longitudinal edges of the strip (6) and the cassette (2) which face each other being engaged with each other, in opposition to the flexural deformation of the strip.

2. Roller blind according to Claim 1, in which the said at least one guide element (10) is supported in the cassette (2) in such a way that it can oscillate to a limited degree.

3. Roller blind according to Claim 1 or 2, in which the axis of oscillation (X) of the said guide element (10) is substantially perpendicular to the direction of unwinding and winding of the fabric (4).

4. Roller blind according to any one of the preceding claims, in which the said guide element (10) is positioned in the proximity of the middle of the longitudinal extension of the said strip (6).

5. Roller blind according to any one of the preceding claims, in which the said guide element (10) comprises a linkage (11) pivoted about the said axis of oscillation (X) and having a first free end (11a) which can interfere with the strip in its approach to the cassette (2) in such a way that the said linkage (11) supports the strip along the arc of oscillation about the said axis (X) to guide the strip in the correct approach to the cassette with the opposing facing edges superimposed on each other.

6. Roller blind according to Claim 5, in which the said linkage (11) is pivoted in the form of a first-class lever about the said axis of oscillation (X) and comprises a second free end (11b), on the opposite side of the fulcrum to the first end (11a), the said second end being capable of bearing on corresponding bearing parts of the cassette to define the limits of the angular oscillatory path of the said linkage (11).

7. Roller blind according to Claim 6, in which the said second end (11b) comprises a first and a second appendage (13a,13b) which can bear, respectively, on a first and a second bearing surface (14a,14b) of the cassette (2), to define the limit angular positions of the oscillation of the said linkage (11).

8. Roller blind according to any one of Claims 5 to 7, in which the said strip (6) is provided with a plate (15) which can interact with the first end (11a) of the said linkage (11) to guide the strip, the said plate (15) and the said end (11a) being capable of contacting each other during the oscillatory travel of the linkage (11), as a result of an approach of the strip to the cassette (2).

9. Roller blind according to Claim 8, in which the said first end (11a) of the linkage (11) and the said plate (15) can make a rolling contact with each other's surfaces.

10. Roller blind according to Claim 9, in which a roller (12d) supported rotatably on the linkage (11) is provided at the said first end (11a) and can contact the plate (15).

11. Roller blind according to Claim 10, in which the said linkage (11) comprises a pair of parallel brackets (12a,12b), spaced apart, between which the said roller (12d) is mounted idly.

12. Roller blind according to any one of Claims 8 to 11, in which the said plate (15) comprises a portion (15b) extending substantially at right angles from a base portion (15a), the shape and relative angles of the said portions (15a,15b) being selected in such a way that the linkage (11) can be moved in oscillation by the plate (15), as a result of their interference with each other, and the plate, in turn, can be supported by the linkage (11) during the oscillatory travel about the fulcrum.

Drawing