Abstract
The invention relates to an operating mechanism for a cordless window covering such as a roller blind, comprising at least one substantially stationary inner shaft which is connectable to the fixed world and at least one axially rotatable drive shaft configured for driving and thereby lowering and/or raising the window covering. The system is in particular configured to provide controlled operation of a cordless window covering.
Claims
1. Operating mechanism for a cordless window covering such as a roller blind, comprising: at least one stationary inner shaft which is connectable to the fixed world, at least one at least partially conically shaped coupling structure which encloses at least part of the inner shaft, at least one urging element configured for urging the coupling structure in axial direction of the inner shaft, at least one axially rotatable drive shaft configured for driving and thereby lowering and/or raising the window covering, wherein the drive shaft encloses at least part of the inner shaft and the coupling structure, and at least one brake shoe configured to cooperate with at least the conically shaped part of the coupling structure and with the axially rotatable drive shaft, wherein the brake shoe, the coupling structure and the drive shaft are positioned such that axially urging of the coupling structure by the urging element causes a radially outward force onto the brake shoe causing the brake shoe to at least partially impedes rotation of the axially rotatable drive shaft.
2. Operating mechanism according to claim 1, wherein the urging element is configured for urging the coupling structure in axial direction of the inner shaft towards the center of the window covering.
3. Operating mechanism according to claim 1, wherein the coupling structure is positioned such that the outer diameter of at least the conically shaped part of the coupling structure decreases in the direction wherein it is axially urged by the urging element.
4. Operating mechanism according to claim 1, wherein at least part of the inner shaft has a non-cylindrical shape and wherein the inner surface of coupling structure has a complementary non-cylindrical shape.
5. Operating mechanism according to claim 1, wherein the coupling structure comprises a cylindrical part configured to enclose at least part of the urging element.
6. Operating mechanism according to claim 1, wherein the stationary inner shaft comprises at least one stop surface configured to form a stop for the urging element.
7. Operating mechanism according to claim 1, wherein the urging element is clamped between the stop surface and an engaging surface of the coupling structure.
8. Operating mechanism according to claim 1, wherein the urging element is formed by a coil spring surrounding the stationary inner shaft.
9. Operating mechanism according to claim 1, comprising a stationary support structure which is connected to the stationary inner shaft and which is configured for connecting the operating mechanism to the fixed world.
10. Operating mechanism according to claim 1, comprises at least one adjusting structure configured to enable adjusting of the maximum axial displacement of the coupling structure and/or to limit the axial displacement of the coupling structure, wherein the adjusting structure is at least partially enclosed between the coupling structure and the drive shaft and/or wherein an inner surface of the adjusting structure comprises at least one slot and wherein the coupling structure comprises at least one protrusion configured for corporation with said slot.
11. Operating mechanism according to claim 1, wherein at least one brake shoe is at least partially flexible.
12. Operating mechanism according to claim 1, wherein at least one brake shoe is at least partially ring shaped.
13. Operating mechanism according to claim 1, wherein at least an inner surface of at least one brake shoe is conically shaped.
14. Operating mechanism according to claim 1, wherein an outer surface of at least one brake shoe is flat.
15. Operating mechanism according to claim 1, wherein an outer surface of at least one brake shoe is profiled.
16. Operating mechanism according to claim 1, wherein the operating mechanism is free of bearings.
17. Operating mechanism according to claim 1, wherein the axially rotatable drive shaft is configured to cooperate with a winding tube which at least partly surrounds said drive shaft, and wherein the winding tube is configured such that at least a part of the window covering can be wound onto it.
18. Operating mechanism according to claim 17, wherein an inner surface of the winding tube comprises at least one coupling element and wherein an outer surface of the drive shaft comprises at least one counter-coupling element configured for corporation with said coupling element of the winding tube, such that rotation of the winding tube results in rotation of the drive shaft, and vice versa.
19. Operating mechanism according to claim 1, comprising at least one torsion spring configured for exerting a torque on the drive shaft, and/or winding tube if applied, during rotation of the drive shaft, and/or winding tube, in a direction opposite to the direction of rotation.
20. Assembly of a window covering and an operating device according to claim 1.
Description
[0029] The invention will be elucidated on the basis of the non-limitative exemplary embodiments shown in the following figures. Within these figures, similar reference numbers correspond to similar or equivalent technical features.
[0030] FIG. 1a shows a perspective view of a cross section an operating mechanism 1 according to the present invention. The operating mechanism 1 is in particular an operating mechanism 1 for a cordless window covering (not shown) such as a cordless roller blind or a cordless roller shade. The operating mechanism 1 comprises a substantially stationary inner shaft 2 in combination with an axially rotatable drive shaft 3. The substantially stationary inner shaft 2 is connected to a support structure 4 which is connectable to the fixed world. The axially rotatable drive shaft 3 is configured for driving and thereby lowering and/or raising the window covering. The drive shaft 3 encloses at least part of the inner shaft 2. The operating mechanism 1 of the shown embodiment further comprises a coupling structure 5 which is partially conically shaped and which encloses part of the inner shaft 2. The inner shaft 2 comprises a stop surface 6 configured to form a stop for an urging element 7. The urging element 7, in the shown embodiment formed by a coil spring 7, is configured for urging the coupling structure 5 in axial direction of the inner shaft 2 facing away from the support structure 4. The urging element 7 surrounds the inner shaft 2. The urging element 7 co-acts with both the stop surface 6 of the inner shaft 2 and with an engaging surface 8 of the coupling structure 5. In fact, the urging element 7 is clamped between said stop surface 6 and said engaging surface 8. The coupling surface 5 has a predetermined axial play, typically of a couple millimetres. This is due to the coupling structure 5 being restricted in its axial movement by the stop surface 6 of the inner shaft 2 and a boundary formed by the drive shaft 3 and/or an adjusting structure 9. The operating mechanism 1 further comprises a brake shoe 10 which is configured to engage part of the coupling structure 5, in particular the conical part of the coupling structure 5. The brake shoe 10 is positioned such that when the urging element 7 urges the coupling structure 5 in axial direction (seen from the inner shaft 2) the brake shoe 10 experiences a radially outward force. Due to said radially outward force the brake shoe 10 engages the axially rotatable drive shaft 3. Due to said engagement between the brake shoe 10 and the drive shaft 3, the drive shaft 3 is slowed down during rotation thereof. Hence, the brake shoe 10 directly cooperates with both the conical part of the coupling structure 5 and the drive shaft 3. The adjusting structure 9 is configured for adjusting the position of the coupling structure 5 and therefore for adjusting the extend of deceleration which can be achieved by the brake shoe 10. In the shown embodiment, the adjusting structure 9 comprises mutually coupled adjusting parts 9a, 9b. The adjusting structure 9 is typically substantially stationary, in particular during raising and/or lowering of the window covering. However, the adjusting structure 9 can be (manually) displaced, in particular rotated, such that the possible maximum axial displacement of the coupling structure 5 can be adjusted. Further, the adjusting structure 9 comprises control elements 11 for manually controlling the brake force. The axially rotatable drive shaft 3 cooperates with a winding tube 12 which at least partly surrounds said drive shaft 3. The winding tube 12 is configured such that at least a part of the window covering (not shown) can be wound onto it. An inner surface of the winding tube 12 comprises at least one coupling element 13 and an outer surface of the drive shaft 3 comprises at least one counter-coupling element 14. The coupling element 13 and counter-coupling element are configured for mutual cooperation such that during rotation of the winding tube 12, typically via pulling or raising the window covering, the winding tube 12 takes along the drive shaft 3 in its rotation. Further, the operating mechanism 1 comprises a plurality of torsion springs 15 configured for exerting a torque on the drive shaft 3 and/or winding tube 12 during rotation of the drive shaft 3 and/or winding tube 12 in a direction opposite to the direction of rotation (of the drive shaft 3). Each torsion spring 15 is in the shown embodiment coupled to an inner spring shaft 16 and to (an) axially rotatable housing 17 which is in the shown embodiment configured for co-action with the winding tube 12. In another conceivable embodiment the torsion springs 15 could for example be directly coupled to the substantially stationary inner shaft 2. However, in the shown embodiment the torsion springs are coupled to the substantially stationary inner shaft through an decelerating transmission 18. The decelerating transmission 18 is configured to rotate the inner spring shaft 16 during rotation of the drive shaft 3 and/or winding tube 12. The decelerating transmission 18 is in particular a planetary transmission, more in particular to provide a 1:4 deceleration.
[0031] FIG. 1b shows the cross section of the operating mechanism 1 as shown in FIG. 1a from a side view. It can be seen that the inner spring shaft 16 is substantially in line with the substantially stationary inner shaft 2. The arrows indicate the axial and radial forces as exerted as a result of the continuous urging of the coupling structure 3 by the urging element 7. The substantially stationary inner shaft 2 has several different radial cross sections depending on which component the inner shaft 2 is co-acting with.
[0032] FIGS. 2a-2e show a series images of the operating mechanism 1 as shown in FIGS. 1a and 1b wherein subsequently an element is peeled off the operating mechanism 1 such that the co-action between the elements can be seen.
[0033] FIG. 2a shows the drive shaft 3 which encloses part of the inner shaft 2. In the shown embodiment, the drive shaft 3 encloses the coupling structure, the brake shoe and the urging element substantially entirely. The adjusting structure 9 is partially enclosed by the drive shaft 3. The drive shaft 3 has a structured outer surface configured for corporation with an inner side of a winding tube (not shown).
[0034] In FIG. 2b the drive shaft is removed, such that the further parts of the adjusting structure 9a. 9b can be seen. Further the brake shoe 10 is visible, which encloses the coupling structure 5. It can be seen that the adjusting parts 9a, 9b of the adjusting structure 9 are mutually coupled via a snap connection. Part of the outer surface of the adjusting structure 9 forms a cylinder. This cylindrically shaped part of the adjusting structure 9 preferably does not engage the drive shaft.
[0035] In FIG. 2c the more centrally located adjusting part 9a is made invisible. It can be seen that the coupling structure 5 comprises a protrusion 19 which is configured for corporation with a slot (not shown) provided in the adjusting structure 9. Rotation of the adjusting structure 9 via the adjusting element 11 will cause the slot to take along the protrusion 19, thereby adjusting the maximum axial displacing of the coupling structure 5.
[0036] FIG. 2d shows an embodiment wherein the rear part 9b of the adjusting structure 9 is made invisible. It can be seen that the inner shaft 2 comprises a stop surface 6. The stop surface 6 also substantially forms an axial boundary for the coupling structure 3.
[0037] FIG. 2e shows that an inner surface of the conically shaped part of the coupling structure 5 has a non-cylindrical shape. This non-cylindrical is complementary to the non-cylindrical shape of part of the inner shaft which co-acts with said conical part of the coupling structure 5. In the shown embodiment an substantially cross-shaped shaft part was applied, and the coupling part 9 substantially follows the contours thereof. Such complementary shapes may prevent rotation of the coupling structure 5, in particular with respect to the inner shaft. Preferably, part of the inner shaft 2 which co-acts with the urging element 7, in particular the coil spring 7, is substantially cylindrical.
[0038] FIGS. 3a and 3b show perspective views of a possible embodiment of a coupling structure 5 for use in an operating mechanism 1 according to the present invention. The coupling structure 5 comprises both a substantially conical part 5a and a substantially cylindrical part 5b. The figures further show that the coupling structure 5 comprises an engaging surface 8 configured for engaging by the urging element (not shown).
[0039] FIG. 4a shows a perspective view of a possible embodiment of a brake shoe 10 for use in an operating mechanism 1 according to the present invention. FIG. 4b shows a frontal view said brake shoe 10. The brake shoe 10 of the shown embodiment is substantially ring shaped, the brake shoe 10 is in particular an open ring. The inner surface of the brake shoe 10 is substantially conically shaped. FIG. 2e for example shows that the brake shoe 10 substantially follows the slope of the conically part of the coupling structure 5. The inner side of the brake shoe 10 is provided with cut out portion which might enhance the flexibility of the brake shoe 10. The outer surface of said brake shoe 10 is in the shown embodiment substantially flat.
[0040] It should be clear that the invention is not limited to the exemplary embodiments shown and described here, but that within the scope of the appended claims, many variants are possible which will be obvious to the person skilled in the art. It is hereby conceivable that various inventive concepts and/or technical features of the embodiments described above can be combined in whole or in part without departing from the inventive concept described in the appended claims.
[0041] The verb comprising and its conjugations included in this patent are not only understood to mean comprising, but are also to be understood as the expressions contain, essentially consist, formed by, and conjugations thereof.
[0042] Further, when it is referred to a brake shoe also the term brake element could have been used. Also the terms operating mechanism and operating device or operating system are interchangeable. Where the term coupling structure is used, there can also be referred to a coupling element. When it is said that the brake shoe is configured to impede rotation of the axially rotatable drive shaft, it is also meant that the brake is configured for braking or slowing down the rotation of the axially rotatable drive shaft.
