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Title:
DOUBLE ROLLER SHADE ASSEMBLY
Document Type and Number:
WIPO Patent Application WO/2017/208276
Kind Code:
A1
Abstract:
The present invention relates to an assembly (1) of a roller shade (4) for shielding an area (12), said area (12) comprising at least an edge (13), said assembly (1) comprising a fixed first driver roller (2) and a second driven roller (3) movable with respect to said first roller (2), and a shade (4) having two ends, each end of said shade (4) being respectively coupled to a respective roller (2, 3), said shade (4) being able to slide between said first roller (2) and said second roller (3) in order to be able to nearly be totally wrapped on one or both said rollers (2, 3), said assembly (1) further comprising driving means (9) acting on said first roller (2) for exercising a wrapping/unwrapping torque (M2-, M2+) on said shade (4) in order to wrap/unwrap said shade (4) on said first roller (2), and return means (11) acting on said second roller (3) for exercising a return torque (M3+) on said shade (4) in order to wrap it on said second roller (3), wherein said assembly (1) is configured so that, during use when said first roller (2) is coupled in a fixed way to an edge (13) of said area (12), and a withdrawing force (Fp; Fs; Fr) acts on said second roller (3) in order to withdraw said second roller (3) from said first roller (2), said assembly (1) is able to pass between a position of non use, wherein said shade (4) is wrapped nearly completely on said first roller (2) and said second roller (3) is arranged in proximity of said first roller (2) in order to leave said area (12) free, and a use position, wherein said shade (4) shields said area (12), and wherein said withdrawing force (Fp; Fs; Fr) and said return means (11) are configured so that: when said assembly (1) is not in said use position, the withdrawing force (Fp; Fs; Fr) acting on said second roller (3) is higher or equal than the resulting forces from said return torque (M3+) so as to prevent the sliding of said shade (4) on said second roller (3); and when said assembly (1) is in said use position, said withdrawing force (Fp; Fs; Fr) is lower than the resulting forces of said return torque (M3+), so as to allow the sliding of said shade (4) on said second roller (3) on the action of said driving means (9).

Inventors:
FALCINELLI, Ernesto (Via Della Ciliegia 2, Assisi, 06081, IT)
Application Number:
IT2017/000112
Publication Date:
December 07, 2017
Filing Date:
June 05, 2017
Export Citation:
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Assignee:
FALCINELLI, Ernesto (Via Della Ciliegia 2, Assisi, 06081, IT)
International Classes:
E06B9/24; E06B9/40
Domestic Patent References:
WO2010000442A12010-01-07
Foreign References:
US20120031568A12012-02-09
US20150068690A12015-03-12
EP2899329A12015-07-29
EP2216490A12010-08-11
EP0783072A11997-07-09
Attorney, Agent or Firm:
SANTI, Filippol et al. (Barzano' & Zanardo Roma S.p.A, Via Piemonte 26, Roma, 00187, IT)
Download PDF:
Claims:
CLAIMS

1. Assembly (1) of a roller shade (4) for shielding an area (12), said area (12) comprising at least an edge (13), said assembly (1) comprising a fixed first driver roller (2) and a second driven roller (3) movable with respect to said first roller (2), and a shade (4) having two ends, each end of said shade (4) being respectively coupled to a respective roller (2, 3), said shade (4) being able to slide between said first roller (2) and said second roller (3) in order to be able to nearly be totally wrapped on one or both said rollers (2, 3), said assembly (1) further comprising driving means (9) acting on said first roller (2) for exercising a wrapping/unwrapping torque (M2-, M2+) on said shade (4) in order to wrap/unwrap said shade (4) on said first roller (2), and return means (11) acting on said second roller (3) for exercising a return torque (M3+) on said shade (4) in order to wrap it on said second roller (3), wherein said assembly (1) is configured so that, during use when said first roller (2) is coupled in a fixed way to an edge (13) of said area (12), and a withdrawing force (Fp; Fs; Fr) acts on said second roller (3) in order to withdraw said second roller (3) from said first roller (2), said assembly (1) is able to pass between a position of non use, wherein said shade (4) is wrapped nearly completely on said first roller (2) and said second roller (3) is arranged in proximity of said first roller (2) in order to leave said area (12) free, and a use position, wherein said shade (4) shields said area (12), and wherein said withdrawing force (Fp; Fs; Fr) and said return means (11) are configured so that: when said assembly (1) is not in said use position, the withdrawing force (Fp; Fs; Fr) acting on said second roller (3) is higher or equal than the resulting forces from said return torque (M3+) so as to prevent the sliding of said shade (4) on said second roller (3); and when said assembly (1) is in said use position, said withdrawing force (Fp; Fs; Fr) is lower than the resulting forces of said return torque (M3+), so as to allow the sliding of said shade (4) on said second roller (3) on the action of said driving means (9).

2. Assembly (1) according to the previous claim, characterized in that said opening (12) comprises a top edge (13) and a lower edge (14), in that said assembly (1) is configured so that, when said first roller (2) is coupled in a fixed way to the top edge (13) of an opening (12), said assembly (1) is able to pass between said non use position, and said use position, wherein said second roller (3) is laid on said lower edge (14) of said opening (12), and in that the mass of said second roller (3) and said return means (11) are configured to that, when said assembly (1) is not in said use position, said weight force (Fp) acting on said second roller (3) is higher or equal than the resulting forces of said return torque (M3+) so as to prevent the sliding of said shade (4) on said second roller (3); and when said assembly (1) is in said use position, said weight force (Fp) is lower than the resulting forces of said return torque (M3+), so as to allow the sliding of said shade (4) on said second roller (3) on action of said driving means (9).

3. Assembly (1) according to the previous claim, characterized in that said return means are a spring coaxial (11) to said second roller (3), in particular a mechanical spring, air or gas.

4. Assembly (1) according to the previous claim, characterized in that it provides a system for adjusting the limit (55) of the shade (4), able to act on said coaxial spring (11) in such a way as to adjust its revolutions.

5. Assembly (1) according to the previous claim, characterized in that it comprises a holder spring (11) hub (50) rotatably coupled to the second roller (3), said system for adjusting the limit (55) of the shade (4) comprising a double profile bushing (55), in which a first profile (56) is coupled to the spring (11) hub so as to act on the same, and the second profile (57) is accessible from the outside of the system.

6. Assembly (1) according to the previous claim, characterized in that it provides screws (53, 54) for fixing the hub (50) to the second roller (3) to prevent its rotation with respect to the second roller (3).

7. Assembly (1) according to the claim 3, characterized in that said return means are motor-powered means.

8. Assembly (1) according to any one of the previous claims, characterized in that said second roller (3) comprises a counterweight (7) able to participate to its mass, said counterweight (7) having a mass based on the dimension and the specific weight of said shade (4) to wrap.

9. Assembly (1) according to the previous claim, when dependent on claim 3, characterized in that, known the data of the spring (11):

- the spring (11) elasticity modulus ε,

- the diameter of spring (11) wire d,

- the average diameter D of the spring (11), - the number of turns N of the spring (1 1),

- the number of spring (1 1) pre-loading turns N0;

known the data of the lower roller (3):

- the radius r of the lower roller (3);

known the shade (4) data:

- the width L of the shade (4),

- net height H of shade fabric (4),

- the thickness S of the shade fabric (4);

thus calculated the necessary turns to rewind the fabric on the second roller (3);

calculated the fixed weight Pf of the spring (11 ),

calculated the linear weight Pi of the lower roller (3), the value P(x) of the additional weight x or counterweight (7) to be added is equal to:

10. Assembly (1) according to the previous claim, characterized in that in case the value P(x) of the additional weight or counterweight (7) is lower than 0, the spring (1 1) pre-loading turns No is increased.

1 1. Assembly (1) according to any one of the previous claims, characterized in further comprising coupling means (8, 10; 18, 19) for removably coupling said second roller (3) to said lower edge (14) of said opening (12) and acting with a coupling force (Fc) on said second roller (3) in order to maintain said second roller (3) coupled to said lower edge (14) in said use position, said coupling means (8, 10; 18, 19) being configured so that when the driving means (9) are activated in order to wrap said shade (4) on said first roller (2) and said assembly (1 ) is in said use position, the coupling force (Fc) is lower than the resulting forces of said wrapping torque (M2-) in order to allow the raising of said second roller (3) from said lower edge (14).

12. Assembly (1) according to the previous claim, characterized in that said coupling means are a couple of ferromagnetic elements (8, 10; 18, 19) exercising a magnetic coupling force (Fc) on said second roller (3), wherein a first ferromagnetic element (8; 18) is coupled to said second roller (3) and the second ferromagnetic element (10; 19) is coupled to the lower edge (14) of said opening (12).

13. Assembly (1) according to any one of the previous claims, characterized in providing in correspondence of said second roller (3) a system (16) of centrifugal deceleration with multiplied friction acting on said return means (11) with an opposite force to the resulting forces of said return torque (M3+).

14. Assembly (1) according to any one of the previous claims, characterized in that said shade (4) comprises at least two portions (41 , 42) arranged one after the other along the length of said shade (4) so that wrapping/unwrapping the two rollers (2 and 3), when said assembly (1) is in use position, one of said two portions (41 , 42) covers completely said opening (12) or both, in partial way, cover completely said opening (12).

15. Assembly (1) according to the previous claim, characterized in that said at least two portions (41 , 42) of the shade (4) are made of different materials and/or have a different decoration and/or have a different consistency according to the different light shading or shielding demanded capacity, and/or are of a filtering type and/or attenuating and/or hiding and/or darkening and/or mosquito net type.

16. Assembly (1) according to any one of claims 14 or 15, characterized in that at least one fabric portion (42) of said shade (4) has an opening (60) so that when said at least one fabric portion (42) covers said area (12), a large portion of it remains uncovered.

17. Assembly (1) according to any one of the previous claims, characterized in that said driving means (9) are a rope, a continuous chain, a winch or a motor reducer.

18. Assembly (1) according to any one of the previous claims, characterized in providing an external case (5, 6) with function of support and containment of one or both of said rollers (2, 3).

19. Assembly (1) according to any one of the previous claims, characterized in comprising a support element (24) for each end of said second roller (3), in that each support element (24, 52) is pivoted to the respective end of said second roller (3), said support elements (24, 52) being able to lean on said lower edge (14) of said opening (12) when said assembly (1), during use, is in said use position.

20. Assembly (1) according to the previous claim, characterized in that each support element (52) has at least a partially circular, preferably semicircular, shape, on which a tooth (58) is provided in the lower part, preferably at the center of gravity (b) of the second roller (3), avoiding rotation-translational movements of the second roller (3) when the assembly is in the operating position.

21. Assembly (1) according to the claim 19, characterized in that each of said support elements (24) has a substantially triangular shape, wherein the apex is pivoted to the respective end of said second roller (3) and the two base ends are apt, during use, to enter in contact with the lower edge (14) of said opening (12) in said use position.

22. Assembly (1) according to claim 19 or 21 , when dependant from claim 8, characterized in comprising at least a lever (25) hinged in one of said ends of said second roller (3) and in that said counterweight (7) is coupled to an end of said lever (25).

23. Assembly (1) according to the previous claim, characterized in comprising a third roller (26) coupled to the second end of said lever (25) and arranged in such way to enter in contact with said shade (4) so as to accompany the wrapping/unwrapping of said shade (4).

24. Assembly (1) according to any one of the previous claims, characterized in comprising a side guide (29) in correspondence of each side of said first and second roller (2, 3), two further secondary rollers (30, 31) having the center of the respective axis unaligned with respect to the center of the axis of the first and second roller (2, 3) and arranged in such a position so to enter in contact with said shade (4) in order to bring the side edges of said shade (4) housed in said side guides (29).

25. Assembly (1) according to claim 1 , characterized in comprising extensible articulated arms (32) and further driving means, said extensible articulated arms (32) having an end coupled to said second roller (3), said assembly (1) being configured so that, during use when said articulated arms (32) have the second end coupled in a fixed way to said at least an edge (13) and act on said second roller (3) with a thrust force (Fs) caused by said further driving means that corresponds to said withdrawal force, said shade is able to pass from said non use position to said use position and vice versa, and in that said thrust force (Fs) and the return means (1 ), are configured so that when the shade (4) is not in said use position, the thrust force (Fs) is higher or equal to the resulting forces of said return torque (M3+), so as to prevent the sliding the shade (4) on said second roller (3), in order to allow the cover of the area to shield, and so that when said assembly (1) is in said use position, the thrust force (Fs) is lower to the resulting forces of said return torque (M3+), so as to allow the sliding of said shade (4) on said second roller (3) on action of said driving means (9).

26. Assembly (1) according to any one of the previous claims, characterized in that said area (12) provides a first side edge (13) and a second side edge (14), in providing a third roller (33) comprising further return means (34) configured so to exercise a return force (Fr) on said second roller (3) when said assembly (1) is in said non use position correspondent to said withdrawing force, in that it is configured so that in said non use position said driving means (9) exercise a wrapping torque (M2-) on said shade (4) such that the resulting forces are higher or equal than said return force (Fr), and in said use position, the resulting forces of said return torque (M3+) are higher than the return force (Fr).

27. Assembly (1) according to any one of the previous claims, characterized in that said driving means (9) are equipped with a first motor or top motor (28) acting on said first roller (2) and connected with a radio control unit (30), in that the second roller (3) comprises a second motor or a lower motor (29) connected to a receiving radio unit (31), and in comprising an encoder, able to detect the position of the second roller (3) when said assembly (1) is in said use position in order to act on said first (28) and second motor (29) for allowing the wrapping of said shade (4) on said second roller (3).

Description:
DOUBLE ROLLER SHADE ASSEMBLY

The present invention relates to a roller shade assembly.

More specifically, the present invention relates to the winding/unwinding mechanism of roller shades comprising two fabrics having different density.

This type of shade is used since it allows varying, with a single rolling mechanism, the darkening capability of the shade fabric according to the specifying needing.

These shades comprise a first lower roller and a second upper roller, each roll being secured to the lower part and to the upper part of an opening, respectively, as a window. Two fabrics of a material of different density are mutually coupled each other and are made sliding over the two rollers so that, by wrapping and rolling the rolls, the fabric slides to shield the opening with one of the two fabrics, depending on the intensity of the light to be shielded.

One problem with this type of shades resides in the fact that, being both rollers fixed to the window, it is never possible releasing the window opening from the fabric.

The prior art document US 2012/031568 A1 describes a roller shade comprising two rollers over which the shade fabric to be rolled is slid, wherein a first driving roller is fixed and a second driven roll is movable with respect to the first one and has return means capable of wrapping the shade on the second roller. This system provides a lateral guide and an element coupled to said second roller, able to slide within a guide counteracting the spring torsion moment when the second roller is hung. In addition, this system provides a complex mechanism that adjusts the limit shade, but absorbs considerable energy and cannot be adjusted after fabrication or installation. In addition, further lower roller stop systems are securely fixed to the door opening threshold to be covered. In conclusion, this system has excessive friction and difficult customization for different users' needing.

The object of the present invention is that of overcoming the drawbacks of the prior art described in the above.

It is object of the present invention an assembly of a roller shade for shielding an area, said area comprising at least an edge, said assembly comprising a fixed first driver roller and a second driven roller movable with respect to said first roller, and a shade having two ends, each end of said shade being respectively coupled to a respective roller, said shade being able to slide between said first roller and said second roller in order to be able to nearly be totally wrapped on one or both said rollers, said assembly further comprising driving means acting on said first roller for exercising a wrapping/unwrapping torque on said shade in order to wrap/unwrap said shade on said first roller, and return means acting on said second roller for exercising a return torque (M3+) on said shade in order to wrap it on said second roller, wherein said assembly is configured so that, during use when said first roller is coupled in a fixed way to an edge of said area, and a withdrawing force acts on said second roller in order to withdraw said second roller from said first roller, said assembly is able to pass between a position of non use, wherein said shade is wrapped nearly completely on said first roller and said second roller is arranged in proximity of said first roller in order to leave said area free, and a use position, wherein said shade shields said area, and wherein said withdrawing force and said return means are configured so that: when said assembly is not in said use position, the withdrawing force acting on said second roller is higher or equal than the resulting forces from said return torque so as to prevent the sliding of said shade on said second roller; and when said assembly is in said use position, said withdrawing force is lower than the resulting forces of said return torque, so as to allow the sliding of said shade on said second roller on the action of said driving means.

Particularly, according to the invention, said opening can comprises a top edge and a lower edge, said assembly can be configured so that, when said first roller is coupled in a fixed way to the top edge of an opening, said assembly is able to pass between said non use position, and said use position, wherein said second roller is laid on said lower edge of said opening, and in that the mass of said second roller and said return means are configured to that, when said assembly is not in said use position, said weight force acting on said second roller is higher or equal than the resulting forces of said return torque so as to prevent the sliding of said shade on said second roller; and when said assembly is in said use position, said weight force is lower than the resulting forces of said return torque, so as to allow the sliding of said shade on said second roller on action of said driving means.

Still according to the invention, said return means can be a spring coaxial to said second roller, in particular a mechanical spring, air or gas.

Always according to the invention, said assembly can provide a system for adjusting the limit of the shade, able to act on said coaxial spring in such a way as to adjust its revolutions.

Particularly according to the invention, said assembly can ccomprise a holder spring hub rotatably coupled to the second roller, said system for adjusting the limit of the shade comprising a double profile bushing, in which a first profile is coupled to the spring hub so as to act on the same, and the second profile is accessible from the outside of the system.

Furthermore, according to the invention, said assembly can provide screws for fixing the hub to the second roller to prevent its rotation with respect to the second roller.

Preferably according to the invention, said return means are motor-powered means.

Further according to the invention, said second roller can comprise a counterweight able to participate to its mass, said counterweight having a mass based on the dimension and the specific weight of said shade to wrap.

Always according to the invention, known the data of the spring:

- the spring elasticity modulus ε,

- the diameter of spring wire d,

- the average diameter D of the spring,

- the number of turns N of the spring,

- the number of spring pre-loading turns N 0 ;

known the data of the lower roller:

- the radius r of the lower roller;

known the shade data:

- the width L of the shade,

- net height H of shade fabric,

- the thickness S of the shade fabric;

thus calculated the necessary turns to rewind the fabric on the second roller;

calculated the fixed weight P f of the spring,

calculated the linear weight Pi of the lower roller,

the value P(x) of the additional weight x or counterweight to be added is equal to: ε · d 4■ [π(25Ν 0 - 2r - 5) + n 2 (2r + S) 2 + 47iHs]

Still according to the invention, in case the value P(x) of the additional weight or counterweight is less than 0, the spring pre-loading turns No is increased.

Always according to the invention, said assembly can comprise coupling means for removably coupling said second roller to said lower edge of said opening and acting with a coupling force on said second roller in order to maintain said second roller coupled to said lower edge in said use position, said coupling means being configured so that when the driving means are activated in order to wrap said shade on said first roller and said assembly is in said use position, the coupling force is lower than the resulting forces of said wrapping torque in order to allow the raising of said second roller from said lower edge.

Preferably according to the invention, said coupling means can be a couple of ferromagnetic elements exercising a magnetic coupling force on said second roller, wherein a first ferromagnetic element is coupled to said second roller and the second ferromagnetic element is coupled to the lower edge of said opening.

Further according to the invention, said assembly can provide in correspondence of said second roller a system of centrifugal deceleration with multiplied friction acting on said return means with an opposite force to the resulting forces of said return torque.

Still according to the invention, said shade can comprise at least two portions arranged one after the other along the length of said shade so that wrapping/unwrapping the two rollers, when said assembly is in use position, one of said two portions covers completely said opening or both, in partial way, cover completely said opening.

Always according to the invention, said at least two portions of the shade can be made of different materials and/or have a different decoration and/or have a different consistency according to the different light shading or shielding demanded capacity, and/or are of a filtering type and/or attenuating and/or hiding and/or darkening and/or mosquito net type.

Further according to the invention, at least one fabric portion of said shade can have an opening so that when said at least one fabric portion covers said area, a large portion of it remains uncovered.

Particularly according to the invention, said driving means can be a rope, a continuous chain, a winch or a motor reducer.

Preferably according to the invention, said assembly can provide an external case with function of support and containment of one or both of said rollers.

Furthermore according to the invention, said assembly can comprise a support element for each end of said second roller, each support element can be pivoted to the respective end of said second roller, said support elements being able to lean on said lower edge of said opening when said assembly, during use, is in said use position.

Still according to the invention, each support element can have at least a partially circular, preferably semicircular, shape, on which a tooth is provided in the lower part, preferably at the center of gravity (b) of the second roller, avoiding rotation-translational movements of the second roller when the assembly is in the operating position.

Further, according to the invention, each of said support elements can have a substantially triangular shape, wherein the apex is pivoted to the respective end of said second roller and the two base ends are apt, during use, to enter in contact with the lower edge of said opening in said use position.

Still according to the invention said assembly can comprise at least a lever hinged in one of said ends of said second roller and said counterweight can be coupled to an end of said lever.

Preferably according to the invention said assembly can comprise a third roller coupled to the second end of said lever and arranged in such way to enter in contact with said shade so as to accompany the wrapping/unwrapping of said shade.

Always according to the invention said assembly can comprise a side guide in correspondence of each side of said first and second roller, two further secondary rollers having the center of the respective axis unaligned with respect to the center of the axis of the first and second roller and arranged in such a position so to enter in contact with said shade in order to bring the side edges of said shade housed in said side guides.

Furthermore according to the invention said assembly can comprise extensible articulated arms and further driving means, said extensible articulated arms having an end coupled to said second roller, said assembly being configured so that, during use when said articulated arms have the second end coupled in a fixed way to said at least an edge and act on said second roller with a thrust force caused by said further driving means that corresponds to said withdrawal force, said shade is able to pass from said non use position to said use position and vice versa, and in that said thrust force and the return means, are configured so that when the shade is not in said use position, the thrust force is higher or equal to the resulting forces of said return torque, so as to prevent the sliding the shade on said second roller, in order to allow the cover of the area to shield, and so that when said assembly is in said use position, the thrust force is lower to the resulting forces of said return torque, so as to allow the sliding of said shade on said second roller on action of said driving means.

Still according to the invention said area can provide a first side edge and a second side edge, can provide a third roller comprising further return means configured so to exercise a return force on said second roller when said assembly is in said non use position correspondent to said withdrawing force, in that it is configured so that in said non use position said driving means exercise a wrapping torque on said shade such that the resulting forces are higher or equal than said return force, and in said use position, the resulting forces of said return torque are higher than the return force.

Finally according to the invention said driving means can be equipped with a first motor or top motor acting on said first roller and connected with a radio control unit, in that the second roller comprises a second motor or a lower motor connected to a receiving radio unit, and in comprising an encoder, able to detect the position of the second roller when said assembly is in said use position in order to act on said first and second motor for allowing the wrapping of said shade on said second roller.

The invention will now be described for illustrative but not limitative purposes, with particular reference to the figures of the enclosed drawings, wherein:

figure 1 shows a sectional side view of the roller shade according to the invention in a first embodiment when in use;

figure 2 shows a front view of the roller shade of figure 1 ; figure 3 shows a sectional side view of the roller shade according to the invention in a second embodiment when in use;

figure 4 shows a sectional side view of the roller shade according to the invention in a third embodiment when in use;

figure 5 shows a sectional side view of the roller shade according to the invention in a fourth embodiment when in use;

figure 6 shows a sectional side view of the roller shade according to the invention in a fifth embodiment when in use;

figures 7a and 7b show a detail of figure 6 in two different operative positions;

figure 8a shows a front view of the roller shade according to the invention when it is in a non-use position;

figure 8b shows a front view of the roller shade according to the invention when in use;

figure 8c shows a front view of the roller shade according to the invention when in use;

figure 9 shows a frontal view of a variant of the second roll of roller shade according to the invention;

figure 10 shows a side view of the roller shade according to the invention in a sixth embodiment;

figure 11 shows a lateral sectional view of a coupling detail between the shade and roller of the roller shade according to the invention;

figure 12a shows a sectional side view of a seventh embodiment of the roller shade according to the invention;

figure 12b shows a top section view of a portion of the roller shade of figure 12a;

figure 12c shows a front view of a portion of the roller shade of figure 12a;

figure 13a shows a sectional side view of an eighth embodiment of the roller shade according to the invention;

figure 13b shows a top view of a section of the roller shade of figure 13a;

figure 14 shows a side view of a variant of roller shade of figure 13a;

figure 15a shows a side view of a ninth embodiment of the roller shade according to the invention, in a non-use position; figure 15b shows a side view of the roller shade of figure 15a, in the operative position;

figure 16a shows a top view of a tenth embodiment of the roller shade according to the invention, in the operating position;

figure 16b shows a front view of the roller shade of figure 16a; figure 16c shows a top view of the roller shade of figure 16a, in a non-use position;

figures 17a and 17b show frontal and lateral views in section of an eleventh embodiment of roller shade according to the invention; and figure 18a shows a lateral cross-sectional view of a further embodiment of the roller shade according to the invention in a non-use position;

figure 18b shows a lateral sectional view of the roller shade of figure 18a in the operating position;

figure 18c shows a sectional front view of the roller shade of figure 18a;

figure 19a shows a lateral view of the roller shade limit system according to the invention;

figure 19b shows a frontal view of the limit adjustment system of figure 19a;

figure 20 shows a lateral view of a variant of the support cover of the second roller of the roller shade according to the invention;

figure 21a shows a cross-sectional view of a further embodiment of the roller shade according to the invention in the operative position;

figure 21b shows a front view of the roller shade of figure 21a. Making reference to figures 1 and 2, it is shown a first embodiment of the roller shade assembly according to the invention indicated by reference numeral 1.

In the following, it will be made reference to a roller shade 1 that can shield the light from openings 12 obtained in buildings, such as a window or a door. Such openings 12 generally have an upper edge 13, a lower edge or threshold 14, and two lateral edges 15 (as specifically shown in figures 9a - 9c).

The roller shade 1 comprises a first roller 2 to be fastened to the upper edge 13 of an opening 12, a second driven roller 3, movable with respect to said first roller 2, and a shade 4 having two ends, each one coupled to a respective roller 2 and 3, and able to slide between said first roller 2 and said second roller 3 so that it can be almost completely wound on one or both rolls 2 and 3.

The first fixed roller 2 may be contained or protected by an outer case 5, such as a containment box, as shown in the embodiment of figure 1 , or can be left open as shown in the embodiments of figures 3 and 4.

The shade 4 preferably has a width and length such that it can occupy the free surface of the opening or open space 12, such as a window or a door of a building, and preferably comprises at least two portions 41 , 42 disposed below to the other along the length of said shade 4, so that by wounding/unwinding the two rollers 2 and 3, one of said two portions 41 , 42 completely covers said opening 12 (as shown in figures 9b and 9c) or both, in a partial manner, completely cover said opening 12 (as shown in figure 2).

Said at least two portions 41 , 42 of the shade 4 are preferably made up of two or more different materials and/or may have a different decoration and/or may have a different consistency depending on the capability to obscure or shield the required light. Such tissue portions can be of a filtering, attenuating, occulting or obscuring type.

In other embodiments, not shown, three or more shade portions may be provided, and hence couplings of three or more fabrics comprised of different material and/or consistency.

The roller shade 1 according to the invention further includes driving means 9 acting on said first roller 2 on said shade 4 with a first winding torque M 2- or a first torque winding M2+ for winding or carrying said shade 4 around said first roller 2 and return means 11 acting on said second roller 3 with a reclining torque M 3+ acting on said shade 4 to wound said shade 4 around said second roller 2.

The roller shade 1 is able to pass between a non-use position in which the shade 4 is nearly completely wound about the first roller 2 and the second roller 3 is positioned close to the first roller 2 so as to leave the opening 12 free, and a position of use in which the shade 4 shield the opening 12 and the second roll 3 is coupled to the lower edge 14 of the opening 12, and vice versa.

The mass of the second roller 3 and the return means 11 are configured so that when the second roller 2 is not resting on the lower edge 14 of the opening 12, in other words when the roller shade 1 is not in the use position, the weight force F p acting on the second roller 3 is equal to or greater than the forces resulting from said return torque M 3+ so as to prevent the sliding (winding or unwinding) of the shade 4 on the second roller 3, and so that when the second roller 3 is supported on the lower edge 14 of the opening 12, i.e. when the roller shade 1 is in the use position, the weight force F p acting on the second roller 3 is less than the resulting forces of said torque M3+ so as to allow said shade 4 to slide (winding or unwinding) on said second roller 3 by driving means 9.

In fact, when the second roller 3 is resting on said bottom edge

14, the weight force F p is annulled being counterbalanced by the resulting force exerted by the resting surface, the lower edge 14, on the second roller 3.

The driving means 9 of the first roller 3 may be a rope, a continuous chain, a winch or a gear motor.

In the embodiments of figures 1 - 3, the return means 11 on said second roller 3 are a mechanical spring coaxial to the second roller 3 having a torque M 3+ acting on said second roller 3. However, in other embodiments said return means 11 can be an air, gas, or motor return spring.

The second movable roller 3 may provide a metallic profile 6 to support the shade 4 when wound on said second roller 3.

Therefore, when the shade 4 is nearly completely wound about the first roller 2, the second movable roller 3 is lifted so as to leave the volume of the opening 12, such as a window, free.

In this position, the coaxial spring 11 with respect to the second roller 3 will be loaded due to the overall weight of the second roller 3.

However, this spring 11 will be free to return to the rest position as soon as the torsion stress generated by the shade 4 ceases.

As shown in figures 8a - 8c, by actuating the first roller 2 by means of the driving means 9 to carry the shade 4 from the first roller 2, the second roller 3 will go down to the bottom of the opening 12 by dragging the first fabric portion 41 of the shade 4 so as to cover all the light of the opening 12 to be shielded until the second roller 3 is positioned at the bottom or bottom edge 14 of the opening 12 (figures 8b), in particular the windowsill or the floor of a door.

When it is further wished intensifying the light intensity for the opening 12, the second portion 42 of the shade 4 will be lowered while continuing to act on the first roller 2 by means of the driving means 9.

The winding torque M 3+ existing in the spring 11 will act on the second roller 3, wrapping the first portion 41 of the shade 4 around the second roller 3.

When it is desired to obtain complete darkening of the opening 12, the second portion 42 of shade 4 will continue unwound from the first roller 2, while the first shade portion 41 will still wind on the second roller 3.

When unwinding of the second portion 42 of the shade 4 is completed, at the height of the opening 12 to be shielded, the first portion 41 of the shade 4 will be completely wound on the second roller 3 while the second portion 42 of the shade 4 will cover all the window surface freed from the previous shade portion 41 (as shown in figure 8c).

Intermediate positions of the two portions 41 , 42 of shade 4 are also possible at the same time on the window 12 by simply adjusting the upward or downward winding of the shade on rollers 2 and 3 (as shown in figure 2).

On the contrary, to free the window 12, it will be necessary to act by means of the driving means 9 on the first or top roller 2 so as to wound all the shade portions 41 and 42 on the first roller 2 by also winding the second roller 3 completely, freeing the window opening 12 (as shown in figure 8a).

In this position, spring 11 will still be automatically pre-loaded. As it can be observed from figure 19b, the coaxial spring 11 is coupled to the second roller 3, where the fabric of the shade 4 flows through a feeder 59 which loads the spring 11 when the fabric of the shade 4 is dragged upward, while the second roller 3 is laid on the sill 14 of the opening 12 to be covered.

Advantageously, the system according to the invention can freely operate in the space simply anchored to the ceiling or upper edge of the opening without the need for additional frames or guides to counteract the moment of the lower roll.

Preferably, the balancing of the lower or second roller 3 with respect to the torque 3+ of the spring 11 is obtained by adding additional weight or counterweight to the special suitable provided on the lateral edge of the lower box 6, an additional weight which decreases while the width of the shade increases and thus the weight of the lower box. An example of the positioning of the additional weight 7 is shown in figure 19a where the additional weights are inserted into the lateral edge of the lower box 6.

The extra weight is nil in the case of low and wide shades, inversely increasing on narrow and very high shades.

Known the data of the spring 11 :

- the spring 11 elasticity modulus ε,

- the diameter of spring 11 wire d,

- the average diameter D of the spring 11 ,

- the number of turns N of the spring 11 ,

- the number of spring 11 pre-loading turns No;

known the data of the lower roller 3:

- the radius r of the lower roller 3;

known the shade 4 data:

- the width L of the shade 4,

- net height H of shade fabric 4,

- the thickness S of the shade fabric 4;

thus calculated the necessary turns to rewind the fabric on the second roller 3;

calculated the fixed weight P f of the spring 11 ,

calculated the linear weight Pi of the lower roller 3,

the value P(x) of the additional weight x or counterweight 7 to be added is equal to:

In case the value P(x) of the additional weight or counterweight 7 is lower than 0, the spring 11 pre-loading turns N 0 is increased.

It should be noted that in the system according to the invention there are no additional limits which need additional power for operation: the balancing between the lower spring and the weight of the assembly in which it is contained works as a finely adjustable limit at all times.

The balancing of the system is obtained indifferently by setting the fabric winding direction inside or outside the first roller, it is only necessary to reverse the internal/external position of the counterweight edge of the bottom driven roller or bottom box.

For a good system operation it will be necessary a perfect balancing between the bottom roller mass 3 and the spring 1 1 moments M 3+ .

Such balancing allows the unwinding of the desired length of the fabric downward or the second portion 42 of the fabric of the shade 4, winding on the bottom roller 3.

If the balancing is correct, unwinding is calibrated on the basis of the height of the opening 12 to be covered, while the exceeding shade 4 fabric will remain wound on the lower roller 3 preventing the second roller 3 unwinding under load.

To precisely calibrate the balancing and length of the lower fabric, the bottom roller limit 3 has been made adjustable. In other words, once terminated the fabric unwinding as required, the second lower roller 3 starts to rise with respect to the sill 14 due to the perfect balancing of the weight of the second roller 3 and the moment M 3+ of the spring 1 1. Such adjustment is possible adjusting the pre-loading turns of the spring 11.

This can be done both when producing the shade or during the installation or in post-operam.

To this end, referring to figures 19a and 19b, the spring 1 1 support hub 50 is independent with respect to the cap or side cover 52 of the box or metal profile 6 and joined to the same by two screws 53, 54.

Said coupling is obtained by means of a double profile bushing 55, in particular a double hexagon bushing 55.

The hexagonal outer surface 56 of the bushing 55 engages with the support spring 1 1 hub 50 while the inner cavity 57 of the bushing 55 receives, during the adjustment step, a hexagonal wrench (not shown in the figures).

When the shade 4 is lowered and the second roller 3 is resting on the sill 14 of the opening 12, the outer locking screw 53 is removed, also loosening the inner screw 54.

Now, the bushing 55 will rotate in the winding (or unwinding) direction of the spring 11 by acting on the inner cavity 57, that, pushing on the spring 1 1 will increase (or decrease) the revolutions of the spring 1 1 until the lower or second roller 3 will tend to rise to reach the balancing point.

The outer lock screw 53 will then be applied, the hexagonal wrench will be removed, and the coupling screw 54 will be clamped. More generally, said limit adjustment system may be a threaded hub rotatable with respect to the outer cap of the lower casing, to which the spring is connected. A hexagonal bushing is connected to said hub, fixing it to the outer cap and at the same time allowing the insertion of an external key into the inner hexagonal hole.

When placing the shade, by this key it is possible adjusting the number of turns of the spring, both depending on the rewinding of the fabric, and as the limit point of the lower assembly. In fact, when the spring turns are equal to the strength needed to lower the fabric and to win the frictions of the system, the bottom tube/box assembly can move upwards thus freeing the window light.

The automatic driving of the lower roller can also occur when the upper rolled is powered by a motor driven by radio pulses supplied by wire feed embedded in the fabrics or electromagnetic waves depending on the new technologies being developed.

Alternatively, as shown in figures 18a - 18c, the upper driving roller 2 may be provided with a first motor or upper motor 28 connected to a radio control unit 30. The upper motor 28 controls the lowering of the lower roller 3. The second roller or lower roller 3 is provided with a second motor or lower motor 29 connected to a receiving radio control unit 31.

By means of an encoder, in particular a radiator reader, the position of the second roller 3 is detected when it arrives at the lower edge 14 of the opening 12. Now, continuing the manoeuvre, the lower motor 31 is simultaneously started by a radio pulse winding the lower fabric of the shade 4 while the upper fabric descends.

The same encoder will read the arrival of the upper fabric at the limit 14 and by radio pulse will simultaneously stop the upper motor 30 and the lower motor 31.

Same philosophy to vary the two fabrics 41 , 42 rising. After winding the lower fabric and lowering the lower roller 3, the upper engine 30 will raise the lower roller 3 upwardly allowing the recharging of the batteries 32 contained in the lower roller to load the lower motor 31.

Therefore, in this case, the displacement force is mainly due to the battery engine located in the lower roller.

The embodiment of the roller shade 1 according to the invention of figure 4 differs from the embodiments described in the above by the fact that it does not provide containment or covering elements for the rollers 2 and 3. Further, it provides that the driving means 9 is a motor acting on said first roller 2 and that the second roller 3 is provided with a counterweight 7 able to contribute to the mass of the second roller 3.

The weight of the counterweight 7 or of the second roller 3 is variable according to the size of the shade 4 to be wound, the number of fabrics used for the shade and their specific weight.

Figure 5 shows a further embodiment of the roller shade 1 according to the invention, which differs from the prior art by further comprising coupling means for removably coupling said second roller 3 to said lower edge 14 of said opening 12 and capable to exercise a coupling force F c .

In the particular embodiment, said coupling means are a pair of magnetic elements 8 and 10 exerting a magnetic force Fc on said second roller 3 and may be a magnet and a ferromagnetic element or two magnets of different polarity.

A first magnetic element 8 is coupled to the second roller 3 and the second magnetic element 10 is secured to the lower edge 14 of the opening 12 to be shielded, such as a window sill.

Therefore, when the second roller 3 is located near the lower edge 14 of the opening 12, the second roller 3 is driven by the magnetic force Fc coupled to the lower edge 14, advantageously preventing that the second roller 3 may move from its support position.

The magnetic force F c exerted by the pair of magnetic elements

8, 10 is in any case smaller than the possible resulting force exerted by the winding torque M 2- acting on said shade 4 by means of said driving means 9 to wind said shade 4 on said first roller 2 and at the same time for driving it from said second roller 3, thus allowing the lifting of the second roller 3 from the sill 14.

In figures 6 and 7a and 7b it is shown a further embodiment of the roller shade 1 according to the invention, comprising magnetic coupling means as in the previous embodiment.

The second roller 2 and the lower edge 14 of the opening 12 are shaped in such a way to allow the diagonal sliding of the second roller 3 with respect to the sill 14.

Particularly, the lower portion 17 of the second roller 3 has a wedge shape. The coupling means in the present embodiment are two pairs of magnetic elements 8, 10 and 18, 19, in which the first pair of magnetic elements 8, 10 has a greater magnetic power than the others 18, 19 and wherein each magnetic element 8 or 18 on the second roller 3 can be combined with each magnetic element 10 or 19 present on the lower edge 14 of the opening 12 to exert the magnetic force Fc on the second roller 3.

When the second roller 3 goes down toward the sill 14, the main magnetic element 8 of the second roller 3 is attracted by the magnetic element 10 with greater power of the lower edge 14, causing a disengagement between the first roller 2 and the second roller 3, as shown in figures 6 and 7a - 7b.

In this position, the shade 4 will be free to slide on the second roller 3.

When it is desired to release the window opening 12, acting on the driving means 9, the higher power magnetic element 8 of the second roller 3 will detach from its counterpart 10 of the lower edge 14 and join the second magnetic element 19 having lower power, repositioning the two rollers 2 and 3 on the same axis, to then finally disengage. This will avoid abrupt disengagement between the second roller 3 and the lower edge 14 of the opening 12, as it could occur in the embodiment described in the above.

Each of the embodiments described in the above, wherein anchorage/fixing of the second roller 3 is provided at the lower edge 14 of the opening 12 has the problem that when disengaging the second roller 3 from the sill 14 by the force exerted by the driving means 9 for winding the shade 4 on the first roller 2, the second roller 3 may make a violent upward movement.

To solve this problem, as shown in figure 9, the second roller 3 may provide a centrifugal deceleration system 16 with multiplied friction acting on return means 11 , in particular on the spring 11 , so as to decelerate the reaction of spring 11 when the second roller 3 is detached from the lower edge 14. Particularly, in order to avoid that when the second roller 3 is detached from said lower edge 14 of said opening 12, the winding force acting on said shade 4 is too intense so as to cause a violent winding of the shade towards the first roller 2. Said centrifugal deceleration system 16 is particularly useful when there is no sufficient weight to counter moment of the spring 11 on the lower roller 3.

In view of the continuous variation of the return moment M 3+ of the return means 11 , in particular of the preloaded spring 11 , although the greater weight is placed on the side of the shade 4 in correspondence of the second roller 3, this will have a continuous rotary movement.

In order to ensure at all times a secure support of the lower roller 3, lateral support elements 24, particularly mobile lateral legs 24, which are rotating by gravity, can be provided on the lateral ends of the second roller 3.

In fact, a support element 24 may be provided for each end of said second roller 3. Each support element 24 is rotated at the respective end of said second roller 3 and is adapted to come into contact with the lower edge 14 of the opening 12 when said assembly, during its use, is in said use position.

As shown in the embodiment of figure 10, each one of said support elements 24 may preferably have a substantially triangular shape, wherein the vertex is secured in rotation to the respective end of said second roller 3 and the two base ends are suitable, during use, to come into contact with the lower edge 14 of said opening 12 in said use position to provide greater stability to the second roller 3.

As described in the above, in order to contribute to the mass of said second roller 3, a counterweight 7 may be provided. In the embodiment of figure 10, a lever 25 may be provided hinged to one of said ends of said second roller 3 and said counterweight 7 is coupled to one end of said lever 25 which is free to rotate with respect to the tie point without interfering with the resting of the support member 24 on the lower edge 14 of the opening 12. Depending on the diameter of the counterweight 7 and on the characteristics of the spring 11 , it can vary their distance from the centre of gravity, or the lever centre, and the weight of the counterweight 7.

In order to obstacle the rotation of the counterweight 7, a third roller 26, coupled to the second end of the lever 25, may be provided and disposed above the second roller 3 in the opposite position with respect to the direction of the shade 4. Said third roller 26 is arranged so as to come into contact with said shade 4 so as to accompany the winding/unwinding of the shade 4.

To ensure optimum operation of the assembly according to the invention, it would be advisable that the lower end of the shade 4, in correspondence of the second roller 3, completely unwind so as to allow the rising of the lower roller 3 to be prevented in order to avoid sliding of the roller 3 with respect to the shade fabric 4. It is therefore preferable that the lower end of the shade 4 is solidly coupled to the second roller 3, as shown in the variant of figure 11 , wherein the lower end of the shade 4 has a pocket shape to accommodate said second roller 3. Further, a portion of said pocket is rigidly coupled to said second roller 3. For example, said second roller 3 may have a seat 27 suitable to accommodate a portion of said pocket and the assembly 1 can provide a locking element 28, e.g. a rubber, having a shape suitable for insertion into said seat 27 to lock said pocket in position. Alternatively, said pocket may be coupled to said second roller 3 by means of a fastening rivet.

Contrary to a traditional darkening system where the fabric is tensioned by a flat bottom profile, in the embodiments shown in figures 12 - 14, the roller shade 1 according to the invention, in the darkening version, provides that rollers 2 and 3 are contained in a respective large size containment element 5 and 6; further there are provided side guides 29 capable of partially covering the side edges of the shade 4 to prevent external light from passing through said opening 12 towards the interior of the environment where the shade 1 is placed.

To simplify assembly 1 , a single-wall guide 29 will be provided with a brush preventing passage of the light, on which the fabric of shade 4 will be in continuous engagement, driven in said guide 29 by two rollers, respectively one upper roll 30 and one lower roll 31 , conditioning the change in diameter of the control rollers 2 and 3.

In other words, the assembly 1 according to the invention, in the darkening version, may comprise a side guide 29 on each side of said rollers 2 and 3, two further secondary rollers 30 and 31 having the centre of the respective misaligned axis in the centre of the axis of the main rollers 2 and 3 and arranged in such a position as to come in contact with said shade 4 so as to bring the edges of said shade 4 into said lateral guides 29 to obscure the light which could possibly pass laterally from said opening 12.

Said guides are additional elements to the assembly according to the invention and have the main purpose of recalculating light for systems where a hard dark is required.

The embodiments of figures 12 and 13 vary with the configuration of the containment member 6 of the second roller 3. In the embodiment of figure 14, there is provided also the support element 24 coupled to the second roller 3.

The containment element or box 6 has a shape with the largest weight on the side where it must oppose to the moment of the return spring and has the possibility to vary said weight with the addition of heavy metal profiles.

As already said, the bottom box 6 containing the second roller 3 and the fabric of the shade 4 has a chamber that can be weighed with internal metal profiles to counteract the rotational movement generated by the spring 11.

Nonetheless, in order not to weigh too much the assembly to be lifted, it will be limited the addition of such weights and the bottom box 6 will rotate a few degrees during the ascent, rotation that will have a reverse sense once the descending bottom box 6 will have touched the sill or floor 14 of the opening 12.

Since when such increasing occurs, the bottom box tends to rotate by 30°, its shape will be rounded as well as the end caps 52, having a slightly larger diameter.

When the box 6 is supported on the sill 14 and begins collecting the fabric 4, the moment decreases and the box tends to return to its rest position.

The round shape of the caps will however make the box moving from the vertical.

As shown in the variant of figure 20, to prevent that the rotation of the lower box 6 makes it moving toward the support surface 14, a tooth 58 will be obtained on the lower portion of the header or lateral cover 52 of the lower case 6, which will stabilize the whole allowing the winding of the fabric without rotation-translational movements. The lateral cover 52 thus acts as a support element for the assembly 1. Preferably, the tooth 58 is positioned at the centre of gravity b of the second roller 3. Further, in a preferred embodiment, the side cover 52 has a diameter slightly above the diameter of the containment element 6 of the second roller 3 to facilitate the resting on the sill/floor 14 of the opening 12 to be covered.

The same principle can be applied to provide a roller shade wherein the shade 4 has a first portion 41 in anti-mosquito net and the second portion 42 in sunlight or filtering sunlight fabric, as shown in figures 17a and 17b. Contrary to the frequent spring-loaded use, this type must be necessarily manoeuvred from the upper axis by means of rope, chain, throttle, and engine.

Making reference to figures 15a and 15b, a different embodiment of the roller shade according to the invention is always indicated by reference numeral 1.

In the present embodiment, the roller shade 1 is of the extensible articulated arm 32 type for covering and protecting an area to be covered, such as a terrace, a patio, or an outside portion of a garden.

Again, the shade 1 includes two rollers 2 and 3 and a shade 4 capable of winding/unwinding between said rollers 2 and 3. In this embodiment, the displacement force acting on said second roller 3 to move it away from said first roller 2, to move the shade from the not use position (figure 15a) to the operating position (figure 15b), is exerted by said articulated arms 32 which exert a push force Fs on said second roller 3. The thrust force Fs is due by additional mechanical or powered driving means, acting on said arms 32 when opening/closing.

Therefore, said thrust force Fs and return means 11 , particularly the spring 11 acting on the shade 4 in said second roller 3, are configured so that when the shade 1 is not in said use position, the thrust force Fs acting on said second roller 3 is greater than or equal to the resulting forces of the return torque M3+ of the return means 11 so as to prevent the shade 4 from sliding on said second roller 3 to cover the area to be shielded, and so that when said assembly 1 is in said use position, the thrusting force Fs acting on said second roller 3 is lower than the resulting forces of said return torque M 3+ , so as to allow the sliding of said shade 4 on said second roller 3 by the action of said driving means 9.

In the present case, the use position of use necessarily correspond to the total opening of the arms 32, but also the partial opening of the arms 32 to cover a smaller area.

The solution according to this embodiment advantageously allows to have different fabrics for shade 4, for example one of the permeable filtering types for the summer season and one watertight for the winter season.

In the specific case, therefore, the action of the weigh mass of the second roller in the embodiment of figures 1 - 9 opposing to the spring action is replaced by the thrust force of the expandable and rigid arms.

Still, the solution according to the present invention can also be applied to roller shades for skylights, as shown in the embodiment of figures 16a - 16c.

In the present embodiment, the roller shade 2 comprises, in addition to the two rollers 2 and 3, a third roller 33, said rollers 2, 3 and 33 having parallel axes and being arranged transversely to the opening/closing direction of the shade 4 for covering an opening 12 of a skylight.

The first stationary roller 2 is driven by driving means 9, such as a chain, a winch or a motor. The second movable roller 3, driven by the first roller 2, provides return means, particularly a spring 11. The shade 4 is wound and slides while winding/unwinding on the two rollers 2 and 3. The function of the displacement force between the two rollers 2 and 3 is in this case made by a third roller 33, further comprising return means 34, particularly a spring, configured in such a way to exert a return force F r on said second roller 3 when said assembly 1 is in said non use position. The spring 34 is loaded to the maximum when the shade 4 is completely wound on the first roller 2, returning the second roller 3 towards itself by exercising said return force F r .

In the non-use position, the driving means 9 have a winding torque M2- on said shade 4 so that it is greater than said return force F r so that only when the shade 4 is rotated the second roller 2 is pulled towards the third roller 3.

In the operating position, i.e. when the second roller 3 is located near the third roller 33, the return means 11 of the second roller 3 are fully loaded so that the return torque M 3+ is higher than the torque of return means 33 + of the third roller 33.

Variation: axis 2 has a limit allowing its starting and the axis 3 loading.

The operation of this variant, instead of playing between the moment difference M3 < M333 acting as a block: when the first roller 2 has completely wound the first portion of fabric 41 on the second roller 3, a limit interferes with the rotation of the axis, then the second roller 3 is forced to follow the fabric towards the first roller 2 while loading the third roller 33.

The system according to the invention can validly be used to solve a particularly perceived problem in the commercial sector: the protection of the displayed goods by the sun's rays.

Usually, the top of the showcases is protected by balconies or shades, but the same is not valid for the bottom of the showcases.

When it is wished protecting the bottom with shades coming down from above, the concealment of the displayed goods is obtained.

With the embodiment shown in figures 21a and 21b, the second portion of fabric 42 will have an opening 60 between two fabric straps 61 so as not to cover the upper part of the showcase and can frame the showcase, wounding above about the first driving roller 2. More generally, at least one portion is not covered, but for minimal parts, on the lateral edges.

Therefore, most of the showcase remains free while the lower portion for the desired portion is variably protected throughout the day.

Of course, even in this case, it is possible to completely clear the showcase by lifting the entire shade in the absence of sun.

The principle of the present invention can conveniently be applied to other types of roller shades, such as, for example, interior shades, vertical and horizontal shades, mosquito nets, gravity fall sun shades or arm supported shades.

The roller shade 1 according to the invention advantageously utilizes a single shade with different characteristics.

Further, with a single mechanism it is possible to completely free the window opening when the shade is not necessary.

Still, it advantageously reduces the dimensions required for the installation of filtering/darkening shades in combination.

In the above, preferred embodiments have been described and variants of the present invention have been suggested, but it is to be understood that those skilled in the art can make modifications and changes without departing from the scope as defined in the enclosed claims.