Retractable blind assembly

Abstract

A retractable blind assembly, includes a moveable rail; a second rail; a covering extending between the moveable rail and the second rail; a first elongate flexible member routed along a first path and a second elongate flexible member routed along a second path; a drive member engaged with the first and second elongate flexible members such that rotating the drive member moves the moveable rail to retract or extend the covering; and a translatable element configured to translate in opposite first and second translation directions, perpendicular to the direction of movement of the moveable rail; wherein the translatable element includes the drive member, and the first path includes a first loop extending around the drive member and the second path includes a second loop extending around the drive member, such that the translatable element translating in the first translation direction increases a length of the first path and correspondingly decreases a length of the second path, and the translatable element translating in the second translation direction increases the length of the second path and correspondingly decreases the length of the first path.

Description

[0001] RETRACTABLE BLIND ASSEMBLY

[0002] The present disclosure is in the field of architectural structure coverings, and in particular retractable coverings which are extended and retracted by moving a moveable rail.

[0003] Many different types of architectural structure covering are known. Architectural structure coverings can be used with any type of architectural opening, for example a window, a door or a skylight. In general, architectural structure coverings provide a shade (such as a blind material, curtain or screen) which is extended across the architectural structure opening, and retracted when not in use.

[0004] Many different types of retractable blinds are also known. Known retractable blinds include roller blinds, pleated blinds, and Roman blinds, to name a few examples. Retractable blind assemblies have a mechanism for retracting and extending the covering. A familiar mechanism is a beaded chain hanging alongside the covering, and engaged with a wheel mounted to the end of the roller tube of a roller blind. A user pulls the beaded chain to rotate the roller tube to extend or retract the covering. Drawbacks of this mechanism include the presence of a free-hanging beaded chain, which may be unsuitable if the blind is to be mounted within a skylight or slanted roof window. Free-hanging chain or cord loops may also pose a risk to child safety.

[0005] Improved retractable blind assemblies provide a covering extending between two rails, such that the covering can be extended or retracted by moving one (or, in some arrangements, both) of the rails. Mechanisms for moving a rail may use elongate flexible members, such as cords or beaded chains, connected to both the rail and a drive shaft.

[0006] However, mechanisms for moving a rail present further challenges. In particular, a moveable rail may become skewed with respect to the architectural opening during assembly, installation and / or use.

[0007] It is an aim of the invention to at least partially address some of the above-mentioned problems. According to an aspect of the invention, there is provided a retractable blind assembly, including: a moveable rail; a second rail; a covering extending between the moveable rail and the second rail; a first elongate flexible member routed along a first path and a second elongate flexible member routed along a second path; a drive member engaged with the first and second elongate flexible members such that rotating the drive member moves the moveable rail to retract or extend the covering; and a translatable element configured to translate in opposite first and second translation directions, perpendicular to the direction of movement of the moveable rail; wherein the translatable element includes the drive member, and the first path includes a first loop extending around the drive member and the second path includes a second loop extending around the drive member, such that the translatable element translating in the first translation direction increases a length of the first path and correspondingly decreases a length of the second path, and the translatable element translating in the second translation direction increases the length of the second path and correspondingly decreases the length of the first path.

[0008] A difference between the length of an elongate flexible member and the length of the path it takes through the assembly may arise, for example due to manufacturing tolerances, which causes the moveable rail to become skewed. For example, in an arrangement in which the first path and second path are arranged symmetrically, a slight difference in length between the first and second elongate flexible members may cause the moveable rail to become skewed when the assembly is installed. Furthermore, small changes in the length of the first or second elongate flexible member can occur during use, which cause the moveable rail to become skewed. In response, the translatable element translates in a direction which lengthens the path length of one of the first and second elongate flexible members and correspondingly shortens the path length of the other elongate flexible member. This compensates for the difference in length between the first and second elongate flexible members, or the change in length of the first or second elongate flexible member, and restores the position of the moveable rail to be square (non-skew) with the architectural opening. Optionally, the retractable blind assembly further includes a motor drive unit configured to move the moveable rail to retract or extend the covering. A motor drive unit allows a user to operate the blind assembly more easily. A motor drive unit also removes the need for a chain or cord loop which a user operates manually to raise and lower the covering, thereby making the assembly more child safe.

[0009] Optionally, the translational element includes the motor drive unit. Because the translatable element includes the drive member engaged with the first and second elongate flexible members, the motor drive unit being translatable (as part of a translatable element) provides a convenient mechanism for increasing and decreasing, respectively, the path lengths of the elongate flexible members. In this way, the translation of the motor drive unit in the first or second translation direction has the effect of self-levelling the moveable rail, in order to restore the position of the moveable rail to be square (non-skew) with the architectural opening.

[0010] Optionally, the motor drive unit is configured to drive the first elongate flexible member around the first loop and drive the second elongate flexible member around the second loop in order to move the moveable rail so as to retract or extend the covering. In this way, adjustment of the path lengths is provided by enabling the mechanism for retracting and extending the covering to be translatable as part of the translatable element. Thus the same components fulfil two functions simultaneously, avoiding the need for a dedicated separate mechanism for adjusting the path lengths.

[0011] Optionally, the motor drive unit includes a drive shaft, a motor configured to rotate the drive shaft, and the drive member, wherein the drive member is mounted on the drive shaft so as to rotate with the drive shaft, such that rotating the drive shaft drives the first and second elongate flexible members around the first and second loops, respectively. Further optionally, the drive member includes first and second drive members mounted on the drive shaft so as to rotate with the drive shaft, such that rotating the drive shaft drives the first and second elongate flexible members around the first and second loops, respectively. A drive member (optionally first and second drive members) mounted directly to the drive shaft of the motor drive unit provides a convenient and compact mechanism for driving the first and second elongate flexible members around the first and second loops, respectively. By operating the motor, the drive member(s) which engage sections of the first and second elongate flexible members are rotated, which causes the first and second elongate flexible members to move around the first and second loops, respectively. Furthermore, the drive member (optionally first and second drive members) mounted on the drive shaft determines the positions of the first and second loops with respect to an axial direction of the drive shaft. For example, the position of the drive member (or the respective positions of first and second drive members) may be fixed to the drive shaft in the axial direction of the drive shaft, with the drive shaft and drive member(s) translating together as part of the translatable element. Alternatively, the drive member (optionally first and second drive members) may be mounted on the drive shaft so as to be slidable in the axial direction of the drive shaft, so as to provide the adjustment of the first and second path lengths. In the latter case, the drive shaft may for example have a non-circular cross section, with the drive member(s) keyed to the drive shaft, such that the drive member(s) are slidable along the drive shaft in the longitudinal direction of the drive shaft, whilst still rotating with the drive shaft. In either case, the path lengths of the first and second elongate flexible members are precisely determined by the position of the drive member(s) in the axial direction of the drive shaft, and the position of the moveable rail can be more precisely maintained.

[0012] Optionally, the retractable blind assembly further comprises a battery for powering the motor, wherein the drive member, or first and second drive members, are located between the motor and the battery. In this way, the drive member(s) can be located towards the centre of the assembly, which allows for the first and second paths to be symmetrically arranged about the drive members.

[0013] Optionally, the first and second elongate flexible members are beaded chains, and the drive member includes first and second pulleys with teeth for engaging the beads of the beaded chains. In arrangements having first and second drive members mounted on a drive shaft, the first and second drive members may be pulleys with teeth for engaging the beads of the beaded chains. By using beaded chains, rather than cords for example, the movement of the elongate flexible members around the first and second loops may be more precisely controlled.

[0014] Optionally, the retractable blind assembly is configured such that, when installed in an architectural opening, the second rail is provided at a fixed location relative to the architectural opening, and the moveable rail moves downwards to extend the covering. This provides a traditional blind arrangement that allows a user to cover the upper part of an architectural opening with a shade material.

[0015] Optionally, the retractable blind assembly is configured such that, when installed in an architectural opening, the second rail is provided at a fixed location relative to the architectural opening, and the moveable rail moves upwards to extend the covering. This provides an arrangement in which a user can cover the lower part of an architectural opening with a shade material, for example to provide privacy.

[0016] Optionally, the retractable blind assembly further includes a track along which the translatable element is configured to translate, wherein the track is provided at a fixed location relative to the second rail, and the moveable rail is moveable between the second rail and the track. By providing the track at a fixed location, in other words not in a moveable rail, this enables the moveable rail to be lighter and smaller. This may be advantageous if the moveable rail is manually moveable, and means that less of the architectural opening is obstructed by the moveable rail.

[0017] Optionally, both ends of the first elongate flexible member are coupled to the moveable rail, optionally to a first end of the moveable rail, and both ends of the second elongate flexible member are coupled to the moveable rail, optionally to a second end of the moveable rail opposite to the first end of the moveable rail. This arrangement provides a way of moving the moveable rail in both direction using only two elongate flexible members. A part of the first / second elongate flexible member adjacent its first end may be pulled in a direction so as to retract the covering, whilst a portion of the first / second elongate flexible member adjacent its second end may be pulled in the opposite direction so as to extend the covering. The first elongate flexible member and / or the second elongate flexible member may be coupled to the moveable rail in such a way that the moveable rail is detachable from the first and second elongate flexible members.

[0018] Optionally, both ends of the first elongate flexible member are fixed to a first traveller, both ends of the second elongate flexible member are fixed to a second traveller, and the moveable rail is detachably coupled to the first and second travellers. Such an arrangement can improve ease of assembly.

[0019] Optionally, the first path includes a third loop extending around a first guide member and the second path includes a fourth loop extending around a second guide member, the first and second guide members provided at fixed locations relative to the second rail. Guide members provided at fixed locations, so as to change the direction of extension of an elongate flexible member, enable a moveable rail to be moved in opposite extension and retraction directions by moving the elongate flexible members in opposite directions around their respective paths.

[0020] Optionally, the first and second guide members are provided adjacent or within the second rail. The second rail provides a convenient location for the first and second guide members, which enables the moveable rail to be moved substantially all the way to the second rail, which may be a head rail, for example.

[0021] Optionally, the track constrains translation of the translatable element to only the first and second translation direction. This enables precise adjustment of the path lengths, by permitting only translation of the translatable element which has the effect of increasing and decreasing the path lengths, respectively, by the same amount.

[0022] Optionally, the translatable element is provided within the moveable rail. By housing the translatable element within the moveable rail, it is not necessary to provide the translatable element at a second location outside of the moveable rail. This may avoid the need for a third rail. Optionally, the retractable blind assembly is configured such that, when installed in an architectural opening, the moveable rail is moveable between a first end and a second end of the architectural opening, and the retractable blind assembly further includes attachment elements configured to attach ends of the first elongate flexible member to the first and second ends of the architectural opening, respectively, and to attach ends of the second elongate flexible member to the first and second ends of the architectural opening, respectively.

[0023] By attaching the ends of the elongate flexible members to ends of the architectural opening, an intermediate section of each elongate flexible member is coupled with the translatable element inside the moveable rail. In this way, the elongate flexible members may move around the first and second loops, respectively, inside the moveable rail, which causes the moveable rail itself to move between the ends of architectural opening.

[0024] Optionally, the retractable blind assembly further includes a mounting frame having first and second ends, with the moveable rail being moveable between the first and second ends of the mounting frame, wherein ends of the first elongate flexible member are fixed to the first and second ends of the mounting frame, respectively, and ends of the second elongate flexible member are fixed to the first and second ends of the mounting frame, respectively. A mounting frame provides a convenient way of installing the blind assembly within an architectural structure opening, and simultaneously provides means for fixing the ends of the elongate flexible members to the ends of the architectural opening.

[0025] Optionally, the retractable blind assembly further includes a track along which the translatable element is configured to translate, wherein the track constrains translation of the translatable element relative to moveable rail to only the first and second translation directions. By constraining the translation of the translatable element to only the first and second translation directions, this ensures that translation of the translatable element will have the effect of increasing the path lengths of one elongate flexible member while correspondingly decreasing the path length of the other elongate flexible member by the same amount. Optionally, the first and second elongate flexible members extend in a direction of movement of the moveable rail on opposite sides of the covering. In this way, the elongate flexible members are provided discretely so as to not obstruct the architectural opening. Furthermore, they may be hidden behind frame members or guide members of the assembly, for example.

[0026] Embodiments of the invention will be more clearly understood from the following description, given by way of example only, with reference to the accompanying drawings in which:

[0027] Figure 1 illustrates an example of a retractable blind assembly in perspective view. Figure 2 illustrates another example of a retractable blind assembly in perspective view. Figures 3A to 3C are schematic illustrations of a mechanism for operating a retractable blind assembly.

[0028] Figure 4 illustrates a motor drive unit including drive members for driving first and second elongate flexible members, in perspective view.

[0029] Figure 5 illustrates the interior of a motor drive unit including drive members for driving first and second elongate flexible members, in perspective view.

[0030] Figure 6 is another schematic illustration of a mechanism for operating a retractable blind assembly.

[0031] Figure 7 shows a front view of a retractable blind assembly operated according to the schematic illustrated in figure 6.

[0032] Figure 8 illustrates an end view of a translatable element mounted on a track, in an arrangement as shown schematically in figure 6.

[0033] Figure 9 illustrates the coupling between an elongate flexible member and the moveable rail in an arrangement as shown schematically in figure 6.

[0034] Figure 10 shows an example of a guide member around which an elongate flexible member is looped, in an arrangement as shown schematically in figure 6.

[0035] Figure 11 is another schematic illustration of a mechanism for operating a retractable blind assembly.

[0036] Figure 12 shows the interior of a moveable rail containing a translatable element, and end caps of the moveable rail guiding the elongate flexible members out of the ends of the moveable rail, in an arrangement as shown schematically in figure 11. Figure 13 illustrates a perspective view of an elongate flexible member being guided out of the moveable rail (not shown) by an end cap of the moveable rail, in an arrangement as shown schematically in figure 11.

[0037] Figure 14 shows the overall paths of the first and second elongate flexible members in an arrangement as shown schematically in figure 11.

[0038] Figure 15 shows a perspective view of the translatable element and how the elongate flexible members are coupled with the translatable element, in an arrangement as shown schematically in figure 11.

[0039] Figure 16 shows an alternative arrangement based on the schematic of figure 11, wherein two moveable rails are provided.

[0040] Figure 17 shows an end cap of a moveable rail and a detachable traveller, for detachably coupling an elongate flexible member to the moveable rail.

[0041] Figure 18 shows another schematic illustration of a mechanism for operating a retractable blind assembly.

[0042] The present disclosure provides a retractable blind assembly in which a covering (which may also be referred to as a covering material, shade, or shade material) extends between a first rail and a second rail. At least the first rail is a moveable rail. Retraction and extension of the covering is performed by moving the moveable rail, selectively, in opposite extension and retraction directions. In other words, movement of the moveable rail by a user causes the covering to retract or extend, as opposed to extension or retraction of the covering causing movement of a free-hanging rail.

[0043] There are several known types of retractable covering that can be operated by moving a moveable rail. The mechanism of the invention can in general be practised with any type of retractable covering. For example, retractable blinds which may be operated using a moveable rail include roller blinds, pleated blinds, Roman shades, Venetian blinds, and honeycomb blinds.

[0044] Retractable blind assemblies are generally configured to be installed within an architectural opening. Architectural openings include windows, slanted roof windows, skylights, doors and archways. An architectural opening occupies an area (or plane), generally defined by a height and width of the opening. The height of an architectural opening extends between top and bottom ends of the architectural opening.

[0045] In the following description, “vertical” and “horizontal” mean in the direction of gravity, and perpendicular to the direction of gravity, respectively. When the retractable blind assembly of the present disclosure is installed within an architectural opening, the moveable rail and the second rail may extend horizontally across the width of the opening, with the moveable rail being configured to move vertically upwards and downwards. This is usually the case when the area defined by the opening is parallel to the vertical direction.

[0046] In some arrangements, the moveable rail and the second rail extend horizontally across the width of the opening, and the directions of movement of the moveable rail have both vertical and horizontal components, the horizontal component being perpendicular to the width of the opening. This is usually the case when the area defined by the opening is not parallel to the vertical direction, for example in a slanted roof window.

[0047] Therefore, in the following description, “upward” and “downward” movement of a moveable rail mean movement in a direction towards the top end of an architectural opening, and movement in a direction towards the bottom end of an architectural opening, respectively. “Upward” and “downward” directions of movement are both perpendicular to the longitudinal extent of the moveable rail, and lie within the plane of the architectural opening.

[0048] In some arrangements, the covering extends between a moveable rail at the bottom of the covering (or at an intermediate position between the top and bottom of the covering) and a fixed second rail (such as a head rail) at the top of the covering. In such arrangements, the moveable rail is moveable upwards to retract the covering, and downwards to extend the covering.

[0049] In other arrangements, the covering extends between a moveable rail at the top of the covering (or at an intermediate position between the top and bottom of the covering) and a fixed second rail (such as a fixed lower rail) at the bottom of the covering. In such arrangements, the moveable rail is moveable downwards to retract the covering, and upwards to extend the covering.

[0050] In some arrangements, the second rail is a second moveable rail, with the covering extending between the first and second moveable rails. In such arrangements, the covering is extended by moving the upper and lower moveable rails away from one another, and the covering is retracted by moving the moveable rails toward one another.

[0051] An example of a retractable blind assembly 100 is illustrated in figure 1. As shown in figure 1, the retractable blind assembly 100 includes a covering 30 extending between a moveable rail 10 and a second rail 20. The moveable rail 10 and second rail 20 are configured to extend in the width direction of an architectural opening. In this example, the second rail 20 is a fixed head rail, provided at a fixed location at the top end of the architectural opening in which the blind assembly is installed. In the present example, the assembly 100 also includes a third rail 21. The third rail 21 is a fixed rail provided at a fixed location at the bottom end of the opening.

[0052] In the present example, the covering 30 is a roller blind which wraps around a roller tube (not shown) located in the second rail 20. The covering 30 is extended by moving the moveable rail 10 downwards so that the covering is unwound from around the roller tube. The roller tube is provided with a roller spring assist, such that when the moveable rail 10 is moved vertically upwards towards the roller tube, the covering 30 wraps around the roller tube so as to be retracted within the second rail 20. In any of the example arrangements described herein, the retractable covering may be a roller covering. It will be appreciated that other types of retractable covering, such as those mentioned above, could be provided instead of a roller blind.

[0053] Alternatively, the second rail 20 housing the roller tube could be provided at a fixed location at the bottom end of the architectural opening in which the blind assembly is installed. Then, a fixed third rail 21 could be provided at a fixed location at the top end of the architectural opening. In this arrangement, the covering 30 is extended by moving the moveable rail 10 upwards so that the covering is unwound from around the roller tube. As in the arrangement of figure 1, the roller tube is provided with a roller spring assist. When the moveable rail 10 is moved downwards towards the roller tube, the covering 30 wraps around the roller tube so as to be retracted within the second rail 20.

[0054] Another example of a retractable blind assembly 100 is illustrated in figure 2. In figure 2, the blind assembly 100 is shown installed within an architectural opening 200. Similarly to the example of figure 1, the blind assembly of figure 2 includes a covering 30 which extends between a moveable rail 10 and a second rail 20. The second rail 20 is a fixed head rail provided at the top end of the architectural opening 200. The moveable rail 10 and the second rail 20 each extend horizontally in the width direction of the opening 200. As with the example of figure 1, the moveable rail 10 is moveable upwards (towards the roller tube) and downwards (away from the roller tube) in order to retract or extend the covering, respectively. The covering 30 of the example of figure 2 is also a roller blind, as described with respect to figure 1.

[0055] However, unlike the example of figure 1, in the example of figure 2, there is no fixed lower rail at the bottom of the assembly. Instead, the moveable rail 10 is moveable all the way to the lower end of the architectural opening 200, so that when the covering 30 is in a fully extended position, the moveable rail 10 has the appearance of a lower rail.

[0056] Although in figures 1 and 2 the assemblies are shown as though installed in an opening wherein the area (or plane) defined by the opening is parallel to the vertical direction, it will be appreciated that these blind assemblies may also be installed within an opening wherein the area (or plane) is not parallel to the vertical direction, for example in a sloped roof window.

[0057] Now, general principles of a mechanism for moving the moveable rail are described with reference to the schematic arrangements of figures 3 A to 3C. As shown in figures 3 A to 3C, covering 30 extends between moveable rail 10 at one end of the covering and second rail 20 at the other end of the covering 30. To retract or extend the covering 30, moveable rail 10 is moveable in directions d3 (to retract) and d4 (to extend). The assembly includes a first elongate flexible member 41 routed along a first path pl and a second elongate flexible member 42 routed along a second path p2. Elongate flexible members 41, 42 may be for example cords or beaded chains. The paths taken by the elongate flexible members may also be referred to as chain routings or cord routings through the assembly. Each path pl, p2 may be defined as a path taken by an elongate flexible member from one end of the elongate flexible member to the other end of the elongate flexible member. As shown in figures 3A to 3C, paths pl and p2 may be configured so as not to cross one another. Apart from an adjustment provided by a translatable element (to be described later), the paths may be arranged such that the lengths of the paths do not otherwise change during operation of the assembly. For example, raising or lowering the moveable rail does not in and of itself change the lengths of the paths pl, p2. The elongate flexible members 41, 42 are secured under tension. Numerous different options for paths pl and p2 are possible, such that rotation of a drive member 58 moves the moveable rail 10 via the elongate flexible members 41, 42. In some path arrangements, the elongate flexible members 41, 42 are directly attached to the moveable rail 10. In other path arrangements, the elongate flexible members 41, 42 are configured to be directly attached to the architectural opening in which the assembly is installed. Preferable arrangements of paths pl and p2 will be described later.

[0058] The assembly 100 also includes a rotatably mounted drive member 58 engaged with the first and second elongate flexible members 41, 42, such that rotating the drive member 58 moves the moveable rail 10 to retract or extend the covering. For example, the drive member 58 may be mounted to a drive shaft, which may be rotatable by a motor and / or manually. The drive member 58 may be provided in the second rail 20, as shown in figure 3 A, in the moveable rail 10, as shown in figure 3B, or at a fixed location outside of the moveable rail and second rail, as shown in figure 3C.

[0059] The elongate flexible members 41, 42 may be engaged with the drive member 58 in various ways. In preferable arrangements, to be described later, the elongate flexible members engage with first and second drive members mounted on a drive shaft. In alternative arrangements, the drive member 58 may include a drive shaft and / or a spool mounted on a drive shaft, with the elongate flexible members engaging with the drive member by being spooled around the spool or drive shaft. In arrangements in which the drive member 58 is mounted on a drive shaft, or includes a drive shaft, the drive shaft may extend horizontally in the width direction of the covering. The drive shaft may be provided in the second rail 20, in the moveable rail 10, or at a fixed location outside of the moveable rail and second rail.

[0060] In general, the elongate flexible members are engaged with the drive member 58 in such a way that rotating the drive member 58 causes the engaged portion of elongate flexible member to be driven, along its longitudinal direction, around the drive member 58. Rotating the drive member 58 in opposite rotational directions causes the engaged portion of elongate flexible member to be driven in opposite directions around the drive member 58. This causes the moveable rail to move so as to extend or retract the covering, as will be described later.

[0061] The elongate flexible members are also coupled, directly or indirectly, to the moveable rail 10. In some arrangements, to be described in detail later, the elongate flexible members 41, 42 are directly coupled to the moveable rail 10, for example by being fixedly attached to the moveable rail 10. The elongate flexible members 41, 42 may also be detachably coupled to the moveable rail 10 (as will be described later). In the examples shown in figures 3A and 3C, the ends of each elongate flexible member 41, 42 are shown to be fixedly attached to moveable rail 10. In this way, driving the engaged portion of elongate flexible member around the drive member has the effect of pulling an end of the elongate flexible member, which is attached to the moveable rail, so as to pull the moveable rail in direction d3 or d4. Rotating the drive member in the opposite rotational direction has the effect of pulling the other end of the elongate flexible member, so as to pull the moveable rail in the opposite direction. Thus, rotating the drive member 58 in opposite rotational directions moves the moveable rail so as to extend or retract the covering, respectively. This will be described in further detail later with respect to preferable arrangements of paths pl, p2.

[0062] In other arrangements, to be described in detail later, the elongate flexible members 41, 42 are indirectly coupled to the moveable rail 10 via the drive member 58 (when the drive member 58 is provided in the moveable rail). For example, the elongate flexible members 41, 42 may be routed through the moveable rail 10, without being fixedly attached to the moveable rail. The elongate flexible members 41, 42 may instead be configured to be fixedly attached to the architectural structure in which the assembly is installed. An example of such an arrangement is shown in figure 3B. In this way, driving the engaged portion of elongate flexible member around the drive member has the effect of pulling an end of the elongate flexible member, which is attached to the architectural structure, so as to move the moveable rail relative to the architectural structure. Driving the elongate flexible member around the drive member in the opposite direction has the effect of pulling the other end of the elongate flexible member, so as to move the moveable rail in the opposite direction. Thus, rotating the drive member 58 in opposite rotational directions moves the moveable rail so as to extend or retract the covering, respectively. This will be described in further detail later with respect to preferable arrangements of paths pl, p2.

[0063] The retractable blind assembly includes a translatable element 50 configured to translate in opposite first and second translation directions dl, d2, perpendicular to the directions of movement of the moveable rail d3, d4. The translatable element 50 includes the drive member 58. Thus the drive member 58, as part of a translatable element 50, is translatable in directions dl and d2. Translation directions dl, d2 may be parallel to the width direction of the covering (or architectural opening).

[0064] The first path pl includes a first loop LI extending around the drive member 58. The second path p2 includes a second loop L2 which extends around the drive member 58. A loop is defined as a curve in a path which causes the path to change direction so as to go back on itself. A loop does not need to be a closed loop. A loop could be a semi-circle or other arc connecting straight portions of a path, for example. In the schematic illustrations of figures 3 A to 3C, the first and second loops appear to be defined within the plane of the architectural opening. However, the arrangement of the loops is not limited in this way. In preferable arrangements, to be described later, the first and second loops lie within a plane perpendicular to the width direction of the covering. Because the paths pl, p2 include loops LI, L2, when the translatable element 50 translates in the first translation direction dl, this has the effect of increasing the length of the first path pl and correspondingly decreasing the length of the second path p2. Loop LI coincides with the point of engagement between the first elongate flexible member 41 and the drive member 58 and loop L2 coincides with the point of engagement between the second elongate flexible member 42 and the drive member 58.

[0065] Referring to the examples of figures 3A to 3C, if the drive member 58 translates in direction dl (toward the right hand side of the image) then the point of engagement between the first elongate flexible member 41 and the drive member 58 (i.e. first loop LI) is moved in the direction dl . This means that the path pl taken by the first elongate flexible member 41 has increased in length. At the same time, the point of engagement between the second elongate flexible member 42 and the drive member 58, namely second loop L2, has moved in direction dl by the same distance. Therefore, the length of path p2 has decreased by the same length by which path pl has increased.

[0066] Were the drive member 58 to translate in the second translation direction d2, then the points of engagement between the elongate flexible members and the drive member 58 (namely loops LI and L2) move by the same distance in direction d2. Then, the length of path p2 increases by a certain amount, whilst the length of path pl decreases by the same amount.

[0067] In this way, the translation of the translatable element 50 can adjust for discrepancies in the lengths of the elongate flexible members 41, 42, by correspondingly adjusting the lengths of the paths pl and p2 which they take through the assembly. The paths pl, p2 and the lengths of the elongate flexible members themselves must be precisely determined for smooth operation of the system and proper alignment of the moveable rail with respect to the architectural opening. For example, if one elongate flexible member is even slightly too long (for example by up to 10 mm) relative to the path along which it is to be routed, this can result in misalignment of the moveable rail with the rest of the assembly, for example the moveable rail becoming skewed / non-horizontal. It is very easy for small changes in the lengths of the first and second elongate flexible members to occur. For example, manufacturing tolerances may mean that one elongate flexible member is slightly too long or too short relative to its path through the assembly. During use, heat from the sun, for example, or material fatigue may cause one elongate flexible member to lengthen more than the other. Furthermore, even if the length of the elongate flexible members themselves are precisely determined according to intended paths, the lengths of the paths themselves may vary slightly when the assembly is installed, for example by installing parts of the assembly which determine the path lengths in slightly different positions. For example, parts of the assembly which hold portions of the elongate flexible member on either side of the assembly in the width direction may be installed with one part slightly higher than the other.

[0068] To address these problems, the translatable element is provided so as to automatically provide an adjustment in the relative lengths of paths pl, p2 to compensate for differences between the lengths of the elongate flexible members and their respective paths. When the moveable rail 10 becomes skewed, a user can move the moveable rail 10 to an end of the opening, such as the top or the bottom end of the opening. Here, the moveable rail contacts an upper rail or lower rail, or an end of the opening itself, so as to become aligned with the top or bottom of the opening, as permitted by the translation of the translatable element. Then, when the user moves the moveable rail 10 away from the end of the covering (i.e. towards an intermediate position) the moveable rail 10 will remain square (non-skewed) with respect to the opening.

[0069] A user is not required to manually translate the translatable element in order to provide the adjustment. The translatable element is always permitted to translate (or slide) in the first and second translation directions. During normal use, the translatable element tends not to translate in the first and second translation directions because it is held by the tension in the first and second elongate flexible members. However, when the moveable rail is moved to an end of the assembly (by hand or otherwise, such by operating a motor drive), then the alignment of the moveable rail causes increased tension in one of the elongate flexible members, so that the translatable element is caused to translate in the appropriate direction. The retractable blind assembly may include a motor drive unit configured to move the moveable rail to retract or extend the covering. In this way, a user may be able to operate the assembly to move the moveable rail by the motor, rather than manually. This is particularly convenient when the retractable blind assembly is for example mounted in a high up position which is difficult to reach. The motor drive unit may be operable to rotate the drive member 58 in opposite rotation directions, selectively, in order to retract or extend the covering, as described above with reference to figures 3 A to 3C.

[0070] A disengagement clutch may be provided in connection with the motor drive unit, to allow a user to select between motorised and manual operation of the moveable rail. For example, the motor drive unit may include a drive shaft, as will be described later, and a disengagement clutch may be provided between the motor and the drive shaft. The disengagement clutch may be as described in WOO 17 / 121875 and EP3312374, which are hereby incorporated by reference in their entireties.

[0071] The translatable element may include the motor drive unit. The drive member 58 may be part of the motor drive unit. As described with reference to figures 3 A to 3C, the translatable element 50 includes the drive member 58, such that translation of the translatable element moves the points of engagement between the elongate flexible members and the drive member 58 so as to adjust the path lengths. When the assembly is motorised, rather than provide a motor drive unit separately to the translatable element, it may be more convenient to include the whole motor drive unit in the translatable element, such that the motor drive unit is translatable in the first and second translation directions.

[0072] In a motorised arrangement, the motor drive unit may be configured to drive the first elongate flexible member around the first loop and to drive the second elongate flexible member around the second loop in order to move the moveable rail so as to retract or extend the covering. In some arrangements, as discussed above, driving the elongate flexible members around their respective first and second loops moves the moveable rail, to which the elongate flexible members are directly coupled. In other arrangements, as discussed above, driving the elongate flexible members around their respective first and second loops causes the elongate flexible members to move through the moveable rail, through which the elongate flexible members are routed, which in turn causes the moveable rail to move to retract or extend the covering. Thus, the mechanism for moving the moveable rail to retract or extend the covering, namely driving the elongate flexible members around the first and second loops, respectively, is translatable in order to provide the path length adjustment. Thus, an additional, separate mechanism for adjusting the path lengths is not required.

[0073] In preferable arrangements, the motor drive unit includes a drive shaft, a motor configured to rotate the drive shaft, and the drive member (which has been described with reference to figures 3A to 3C). Preferably, the drive member includes first and second drive members mounted on the drive shaft so as to rotate with the drive shaft. An example of such an arrangement is illustrated in figure 4. In the arrangement of figure 4, the translation directions dl, d2, and the axial direction of the drive shaft, may be parallel to the width direction of the covering.

[0074] Figure 4 shows a motor drive unit 51 including a drive shaft (not shown) on which are mounted first and second drive members 54, 55. The first and second drive members 54, 55 may be provided as separate members or as a single unit. The first and second drive members 54, 55 are mounted on the drive shaft so as to rotate with the drive shaft, for example, the first and second drive members may be keyed to the drive shaft. If the first and second drive members are separate members, a separation distance between the first and second drive members 54, 55 in an axial direction of the drive shaft is preferably fixed. This enables a corresponding increase and decrease in lengths of the paths pl, p2, when the drive members, 54, 55 translate in the first and second translation directions dl, d2. The first and second translation directions, dl, d2 may be parallel to the axial direction of the drive shaft 53 of the motor drive unit of 51.

[0075] The first and second drive members 54, 55 engage a section of the first elongate flexible member 41 and a section of the second elongate flexible member 42, respectively, such that rotating the drive shaft drives the first and second elongate flexible members 41, 42 around the first and second loops LI, L2, respectively. The first and second drive members 54, 55 define the first and second loops LI, L2, respectively. The first and second drive member 54, 55 may be wheels or pulleys, with loops LI, L2 defined by the circumference of the wheels / pulleys. An axial direction of the wheel / pulley may be parallel to the axial direction of the drive shaft.

[0076] The particular section of the elongate flexible member which is engaged by the drive member at any one time changes as the elongate flexible member moves around the loop and around the drive member. The engagement between an elongate flexible member and its respective drive member defines the position of the engaged section of elongate flexible member (and the respective loop LI or L2), relative to the drive shaft, in the translation directions dl, d2 of the translatable element. This means that the translation of the motor drive unit 51, and thus the drive members 54, 55, as part of the translatable element, increases the length of one path by a given amount, and decreases the length of the other path by the same given amount.

[0077] In the example illustrated in figure 4, the translatable element includes the motor drive unit, which includes the first and second drive members. In alternative arrangements, the translatable element may include the drive member(s) but not the motor and drive shaft. For example, the drive member (optionally first and second drive members 54, 55) may be mounted on the drive shaft so as to rotate with the drive shaft, and may be slidably mounted on the drive shaft so as to be translatable in the first and second translation directions dl, d2 relative to the drive shaft. In other words, in some arrangements, the motor and the drive shaft may not be permitted to translate in the first and second translation directions dl, d2. In a non-motorised arrangement, the drive member(s) may be slidably mounted to a drive shaft which is not permitted to translate in the first and second translation directions dl, d2.

[0078] Returning to the example of figure 4, the translatable element 50 may also include guiding portions 57 for guiding the first and second elongate flexible members 41, 42 alongside the translatable element, in the first and second translation directions. The translatable element 50 may also include guiding portions 57 which guide the first and second elongate flexible members 41, 42 from alongside the translatable element, to extend around the drive members 54, 55, respectively. In the arrangement of figure 4, the first elongate flexible member extends from one side of the assembly, in the first translation direction dl (i.e. in the width direction of the covering), alongside and in front of the translatable element 50 until it reaches the drive member 54. Then, guiding portions 57 guide the first elongate flexible member 41 upwards to extend around loop LI around the drive member 54. Then, the first elongate flexible member 41 is guided by guiding portions 57 to extend back in direction d2, alongside and behind the translatable element 50, back to the side of the assembly. The second elongate flexible member 42 is arranged in a symmetric manner on the other side of the assembly.

[0079] Another example of a motor drive unit 51 in which first and second drive members 54, 55 are provided is shown in figure 5. In this arrangement, the engagement between the drive members 54, 55 and the elongate flexible members 41, 42 is the same as described with respect to figure 4. In the figure 5 arrangement however, the first elongate flexible member 41 approaches the first drive member 54 in direction dl from above the first drive member, extends downwards and then back up around the loop LI defined by the first drive member 54, and is subsequently routed back in direction d2 from above the first drive member 54. The second elongate flexible member 42 and the second drive member 55 are arranged similarly on the other side of the assembly. In the figure 5 arrangement the motor drive unit 51 is provided inside the moveable rail 10 (not shown). Therefore, the first and second elongate flexible members 41, 42 move around the loops LI, L2 whilst the motor drive unit 51 including the drive members 54, 55 translates in a direction of movement of the moveable rail.

[0080] As shown in figures 4 and 5, the first and second elongate flexible members may be a first beaded chain and a second beaded chain (also known as bead chains), respectively. The first and second drive members may be pulleys with teeth (or other protrusions or recessions) for engaging the beads of the beaded chains. By using beaded chains, rather than cords for example, the movement of the elongate flexible members around the drive members is more precisely controlled. With each rotation of the drive shaft, the same length of each elongate flexible member is driven around the first loop LI or second loop L2, respectively, such that each end of the moveable rail 10 moves through the same distance. In a motorised assembly, the assembly may further include a battery for powering the motor, with first and second drive members located between the motor and the battery. For example, if the motor unit 51 is provided within a fixed rail, such as fixed lower third rail 21 shown in the arrangement of figure 1 (or alternatively a fixed upper third rail), then the motor and battery may be provided on opposites sides of the first and second drive members, with the first and second drive members located approximately in the centre in the width direction of the assembly. Alternatively, the battery may be provided on the other side of the motor to the first and second drive members.

[0081] Similarly, if the motor drive unit is provided in the moveable rail 10, for example in the arrangement shown in figure 2, then the drive members may be provided approximately centrally in the width direction of the assembly, with the motor and battery on either side. Alternatively, the motor may be provided between the battery and the first and second drive members.

[0082] The battery may be included as part of the translatable element, such that the battery translates in the first and second translation directions along with the motor drive unit. In such an arrangement, the battery may be provided inside the motor drive unit. Alternatively, the battery may be provided at a fixed location near the motor drive unit, with a power cable connecting the motor and battery which has enough flexibility to allow the motor drive unit to slide whilst the battery remains stationary in the first and second translation directions. It should be noted that the battery (along with motor drive unit) would be permitted to move in the direction of movement of the moveable rail, if the motor drive unit and battery are provided inside the moveable rail, even if the battery is not permitted to move relative to the moveable rail.

[0083] Preferable arrangements of paths taken by the first and second elongate flexible members will now be described. The retractable blind assembly may be configured such that, when installed in an architectural opening, the second rail is provided at a fixed location relative to the architectural opening. The second rail may be provided at the top of the architectural opening / assembly. Then, the moveable rail is moved upwards (towards the fixed second rail) to retract the covering, and downwards (away from the fixed second rail) to extend the covering. Alternatively, the second rail may be provided at the bottom of the architectural opening / assembly, with the moveable rail being moved downwards (towards the fixed second rail) to retract the covering, and upwards (away from the fixed second rail) to extend the covering. In some arrangements, the second rail is also a moveable rail. These different configurations are discussed in more detail below.

[0084] A preferable arrangement of paths taken by the first and second elongate flexible members, and how the mechanism for moving the moveable rail is implemented in such an arrangement, will now be described with reference to figures 6 to 10. The general principles of the mechanism as described with reference to figures 3A to 3C apply also to the arrangement of figures 6 to 10. The example motor drive unit described with reference to figure 4 may be used in the arrangement of figure 6.

[0085] Figure 6 is a schematic illustration of the mechanism for moving the moveable rail. As shown in figure 6, a covering 30 extends between a moveable rail 10 and a second rail 20. In the example of figure 6, the second rail 20 is a fixed rail, such as head rail, configured to be provided at a fixed location relative to the architectural opening in which the blind assembly is installed. As shown in figure 6, first elongate flexible member 41 is routed along first path pl and second elongate flexible member 42 is routed along second path p2. Figure 6 schematically illustrates the first loop LI of the first path pl and the second loop L2 of the second path p2, coupled by a translatable element 50 (details of the coupling of the first and second loops by the translatable element is described above in detail with reference to figures 3 A to 5). The translatable element 50 optionally includes the motor drive unit 51 as described above.

[0086] In figure 6, a motor drive unit 51 is schematically depicted between the loops LI, L2 in the width direction of the covering. In motorised arrangements however, preferably first and second drive members are provided on one side of the motor, such that loops LI, L2 are positioned on one side of the motor, in the first or second translation direction, for example as shown in figures 4 and 5. The blind assembly may include a track (not shown in figure 6) along which the translatable element 50 is configured to translate. The track may be provided at a fixed location relative to the second rail 20, with the moveable rail 10 being moveable between the second rail 20 and the track, in the directions d3, d4. The track may be provided at a fixed location relative to the architectural opening in which the blind assembly is installed. In the example of figure 6, the track is provided at the bottom end of the opening. Optionally, the track is provided within a third rail 21 which houses the track and the translatable element 50. However, the provision of a third rail 21 is not essential. In alternative arrangements, the track could be provided at the top end of the covering, for example in a fixed head rail, as depicted in figure 3 A.

[0087] Figure 7 shows a front cut away view of the retractable blind assembly shown in figure 1 which includes the mechanism schematically illustrated in figure 6. In this example, the translatable element 50 includes the motor drive unit 51, as described above. Drive members 54, 55 mounted on the drive shaft are provided, to engage the first and second elongate flexible members 41, 42, as described above. The arrangement of the translatable member and first and second elongate flexible members shown in figure 7 is the same as illustrated in figure 4 and is described above in respect of figure 4.

[0088] Figure 8 illustrates an end view of the translatable element as viewed along the first and second translation directions. Figure 8 shows the translatable element 50 mounted on a track 70 along which the translatable element can move in the first and second translation directions dl, d2. In the example of figure 8, the track 70 is provided as a part of the fixed third rail 21. The track 70 may extend along the entire width of the fixed third rail 21. The track 70 may include two protrusions as shown in figure 8. Clips 56 are provided on the translatable element 50 for clipping the translatable element to the protrusions of the track 70. Preferably, the track is formed of a metal, such as aluminium, and the clips 56 are formed from a plastics material. The plastics material of the clips reduces the transmission of noise caused by movement of the motor, when the translatable element includes a motor drive unit. Optionally, the track constrains translation of the translatable element to only the first and second translation directions. This enables precise adjustment of the path lengths, by permitting only translation of the translatable element which has the effect of increasing and decreasing the path lengths, respectively, by the same amount. Thus, the cross- sectional shape of the track 70 shown in figure 8 may be the cross-sectional shape at any point along the length of the track in the translation directions.

[0089] Both ends 411, 412 of the first elongate flexible member 41 may be fixedly attached to the moveable rail 10, and both ends 421, 422 of the second elongate flexible member 42 may be fixedly attached to the moveable rail 10, as shown in figure 6. Optionally, the first and second ends 411, 412 of the first elongate flexible member 41 are coupled to a first end 11 of the moveable rail 10. Optionally, the first and second ends 421, 422 of the second elongate flexible member 42 are coupled to a second end 12 of the moveable rail 10. The ends 11, 12 of the moveable rail 10 may be provided with respective first and second end caps 13, 14, which include means for attaching the ends of the elongate flexible members to the moveable rail 10. An example of such an end cap 13 is illustrated in figure 9. In addition to means for attaching the ends of one of the elongate flexible members, each end cap may include a guiding portion for guiding an intermediate portion of the same elongate flexible member, as it extends in the direction of movement of the moveable rail, alongside the side of the covering. In any of the arrangements described herein wherein both ends of each elongate flexible member are secured to the moveable rail, both ends of each elongate flexible member may be detachably secured to the moveable rail, for example as described below.

[0090] In some arrangements, both ends 411, 412 of the first elongate flexible member 41 are fixed to a first traveller 131, both ends 421, 422 of the second elongate flexible member 42 are fixed to a second traveller, and the moveable rail 10 is detachably coupled to the first and second travellers. An arrangement of a traveller 131 detachably coupled to the moveable rail 10 is illustrated in figure 17. The upper part of figure 17 shows first end 11 of moveable rail 10 coupled to first traveller 131 (in this case via first end cap 13). The lower part of figure 17 shows the first traveller 131 and the first end 11 of the moveable rail 10 detached from one another (by detachment of the first traveller 131 from the first end cap 13). Figure 17 shows the first end 11 of the moveable rail, which may be on the left-hand side of the blind assembly when viewed from the room side. It will be appreciated that the second end 12 of the moveable rail may be configured in exactly the same way.

[0091] Each traveller 131 is a member to which both ends of an elongate flexible 41, 42 member may be fixedly secured, such that movement of an elongate flexible member 41, 42 around its path (as described above) causes movement of the associated traveller 131 in the extension or retraction direction of the covering. Each traveller 131 is also configured to be coupled to the moveable rail 10. For example, the first end 11 of the moveable rail 10 and the first traveller 131 may be configured to be coupled to one another by a snap fit or push fit connection. Similarly, the second end 12 of the moveable rail 10 and the second traveller may be configured to be coupled to one another by a snap fit or push fit connection. The first and second travellers 131 may be coupled to respective end caps 13, 14 located at the first and second ends 11, 12 of the moveable rail 10. For example, the first traveller 131 may be detachably coupled to the first end cap 13 by a snap fit or push fit connection, as shown in Figure 17. Similarly, a second traveller 131 may be detachably coupled to the second end cap 14 by a snap fit or push fit connection. Other types of detachable connection could also be used, which enable a user to uncoupled the moveable rail from the first and second elongate flexible members.

[0092] Each traveller 131 may also be configured to be moveably coupled with a respective guide rail. First and second guide rails may extend in the direction of movement of the moveable rail and be situated on opposite sides of the covering in the width direction of the assembly, The guide rails guide the movement of the first and second travellers 131, and thus guide the movement of the moveable rail when it is coupled to the first and second travellers 131, in the extension and retraction directions of the covering.

[0093] The detachability of the moveable rail 10 from first and second travellers 131 improves ease of manufacture, because it allows the arrangement of the first and second elongate flexible members and the translatable element (optionally also a motor drive) to be manufactured separately from the arrangement of the second rail and the covering, by decoupling these two arrangements. This also makes installation easier, because the two parts of the whole assembly can be installed separately, before being coupled to one another by attaching the moveable rail to the travellers.

[0094] The detachability of the moveable rail from first and second travellers is particularly advantageous when the second rail is provided at a fixed location at the bottom of the assembly and the covering is a roller blind. Dirt and dust can fall onto the roller tube which needs to be cleaned periodically. This is much easier for a user to do when the moveable rail is detachable, allowing access to the roller tube and the rear side of the covering for cleaning. In such arrangements, the front of the second rail (which houses the roller tube) may be removable by a user, to facilitate access to the roller tube for cleaning for example.

[0095] Returning to figure 6, as shown in figure 6, the first path may include a third loop L3 and the second path may include a fourth loop L4. Guide members (not shown in figure 6) are provided which define the loops L3 and L4 around which the first and second elongate flexible members, respectively, extend. The loops L3 and L4 are provided at a fixed location relative to the second rail 20 and relative to the opening in which the assembly is installed.

[0096] In this way, the first elongate flexible member 41 is routed along path pl which begins at a first end 411 of the elongate flexible member 41, which is fixedly attached to the moveable rail 10. Then the path extends in the direction d3 to the top end of the assembly (or the architectural opening), where it extends around the loop L3 to change direction. From the loop L3, the path pl then extends in the direction d4 all the way to the bottom end of the assembly (or the architectural opening) to then be routed in the direction dl towards the translatable element 50 to which it is coupled at the first loop LI . At the first loop LI the first path Pl again changes direction to extend in direction d2 back towards the side of the assembly, in a lower corner of the assembly. From here, the path pl then extends upwards in direction d3 back to the moveable rail 10, with the second end 412 of the elongate flexible member 41 being fixedly attached to the moveable rail. On the other side of the covering, path p2 begins at end 421 of the elongate flexible member 42, with end 421 being fixedly attached to moveable rail 10. From here, the path p2 extends upwards in direction d3 to the top end of the assembly (or of the opening) to the fourth loop L4. At the fourth loop L4, path p2 changes direction and then extends downwards in direction d4 all the way to the bottom of the assembly (or opening). At this point, the path p2 again changes direction to extend in the direction d2 (in the width direction of the covering / opening) towards the translatable element, to which the second elongate flexible member 42 is coupled. At loop L2, the path p2 changes direction and then extends in direction dl back to the side of the assembly / opening, from where it changes direction to extend upwards in direction d3 back to the moveable rail 10. The path p2 ends at the moveable rail, where end 422 of flexible member 42 is fixedly attached to the moveable rail 10.

[0097] This routing of the elongate flexible members around paths pl and p2 allows the moveable rail 10 to be moved in both extension and retraction directions by operating a single drive shaft. When the drive shaft rotates in a first rotational direction, the elongate flexible members are driven around loops LI and L2 so as to pull moveable rail 10 downwards, by virtue of increased tension in sections of the elongate flexible members between loops LI and L2 and ends 412 and 422. When the drive shaft is rotated in the opposite rotational direction, the moveable rail is moved upwards in direction d3, by virtue of increased tension in the sections of elongate flexible member between loops LI, L2 and ends 411, 421, with these sections of elongate flexible member being routed around loops L3 and L4 to enable the moveable rail to be pulled upwards.

[0098] The guide members 81, 82 which define the loops L3, L4 in paths pl, p2, respectively, may be provided adjacent or within the second rail 20. Guide members 81, 82 may be pulleys with teeth (or alternatively shaped parts) for engaging beads of the beaded chains, when the elongate flexible members are configured as beaded chains. An example of such a guide member is shown in figure 10. Alternatively, the guide members may be configured as smooth pulley wheels, for example. The shapes of the guide members 81, 82 may define loops LI, L2, respectively. When guide members 81, 82 are pulleys or wheels (smooth or with teeth) then the loops LI, L2 may be defined by a section of the circumference of the pulley / wheel, such as a semi-circular section.

[0099] In the schematic of figure 6, the second rail is shown to be provided at the top of the architectural opening / assembly. The moveable rail is moved upwards in direction d3 to retract the covering, and downwards in direction d4 to extend the covering. However, the arrangement described with respect to figure 6 could equally be provided as a reversed arrangement, with the fixed second rail at the bottom of the architectural opening / assembly, and with the moveable rail being moved downwards (direction d4 in figure 6) to retract the covering, and upwards (direction d3 in figure 6) to extend the covering.

[0100] A reversed arrangement is shown in figure 18. In reversed arrangements, the second rail 20 is provided at a fixed location at a bottom end of the architectural opening, and the track is provided at the top end of the opening. Optionally, a third rail 21 is provided at a fixed location at the top end of the opening, housing the track and translatable element 50, and optionally a motor drive 51.

[0101] With reference to figure 18, in a reversed arrangement, the paths pl, p2 are configured as follows. The first elongate flexible member 41 is routed along path pl which begins at a first end 411 of the elongate flexible member 41, attached to the moveable rail 10. Then the path extends downwards in direction d4 to the bottom end of the assembly, where it extends around the loop L3 to change direction. From the loop L3, the path pl then extends upwards in direction d3 all the way to the top end of the assembly to then be routed in the direction dl towards the translatable element 50 to which it is coupled at the first loop LI . At the first loop LI the first path pl again changes direction to extend in direction d2 back towards the side of the assembly, in an upper comer of the assembly. From here, the path pl then extends downwards in direction d4 back to the moveable rail 10, with the second end 412 of the elongate flexible member 41 being attached to the moveable rail. On the other side of the covering, path p2 begins at end 421 of the elongate flexible member 42, with end 421 being attached to moveable rail 10. From here, the path p2 extends downwards in direction d4 to the bottom end of the assembly to the fourth loop L4. At the fourth loop L4, path p2 changes direction and then extends upwards in direction d3 all the way to the top of the assembly. At this point, the path p2 again changes direction to extend in the direction d2 (in the width direction of the covering / opening) towards the translatable element 50, to which the second elongate flexible member 42 is coupled. At loop L2, the path p2 changes direction and then extends in direction dl back to the side of the assembly / opening, from where it changes direction to extend downwards in direction d4 back to the moveable rail 10. The path p2 ends at the moveable rail, where end 422 of flexible member 42 is attached to the moveable rail 10.

[0102] Another preferable arrangement of paths taken by the first and second elongate flexible members, and how the mechanism for moving the moveable rail is implemented in such an arrangement, will now be described with reference to figures 11 to 15. In the arrangement of figures 11 to 15, the translatable element is provided within the moveable rail. The general principles of the mechanism as described with reference to figures 3A to 3C apply also to the arrangement of figures 11 to 15. The example motor drive unit described with reference to figure 5 may be used in arrangements as schematically shown in figure 11.

[0103] Figure 11 shows a schematic illustration of the mechanism of the present disclosure for moving a moveable rail, when the translatable element is provide inside the moveable rail. As shown in figure 11, a covering 30 extends between moveable rail 10 and second rail 20. In this example, the second rail 20 is a fixed rail, such as a head rail, provided at a fixed location at the top of the assembly / opening. As shown in figure 11, first elongate flexible member 41 is routed along first path pl and second elongate flexible member 42 is routed along second path p2. Figure 11 schematically illustrates the first loop LI of the first path pl and the second loop L2 of the second path p2, coupled by a translatable element 50 (details of the coupling of the first and second loops by the translatable element is described above in detail with reference to figures 3 A to 5). As shown in figure 11, the translatable element 50 is provided inside the moveable rail 10. The translatable element 50 optionally includes the motor drive unit 51 as described above. Where the translatable element includes a motor drive unit, the motor drive unit 51 is also included within the moveable rail 10. A preferable arrangement of a motor drive unit configured to be provided inside a moveable rail is illustrated in figure 5 and has already been described with reference to that figure.

[0104] In figure 11, the motor drive unit is schematically depicted between the loops LI, L2 in the width direction of the covering. However, in motorised arrangements, preferably first and second drive members are provided on one side of the motor, such that loops LI, L2 are positioned on one side of the motor, in the first or second translation direction, for example as shown in figures 4 and 5.

[0105] The retractable blind assembly is configured such that, when installed in an architectural opening, the moveable rail 10 is moveable between a first end and a second end of the architectural opening. The first and second ends of the architectural opening may be the top end and bottom end, respectively. The retractable blind assembly may further include attachment elements configured to attach ends of the first elongate flexible member to the first and second ends of the architectural opening respectively, and to attach ends of the second elongate flexible member to the first and second ends of the architectural opening, respectively. This results in a different arrangement of paths pl, p2 than the arrangement described with reference to figure 6.

[0106] In the arrangement of figure 11, path pl begins at a top end of the assembly (or of the opening), with end 411 of elongate flexible member 41 being fixedly attached at a top end of the assembly (or opening). Then, path pl extends downwards in direction d4 until it reaches the position of moveable rail 10. Then, path pl changes direction to extend horizontally in direction dl inside the moveable rail 10, until it reaches loop LI. At loop LI, path pl changes direction to extend back on itself in direction d2, back to the end of the moveable rail 10 which it had entered. Then, path pl exits the moveable rail 10 and extends downwards in direction d4 all the way to the bottom end of the assembly (or opening). Here, end 412 is fixedly attached at the bottom end of the assembly (or opening).

[0107] On the other side of the assembly, path p2 begins at the top end of the assembly (or opening), where end 421 of elongate flexible member 42 is fixedly attached. Then path p2 extends downwards in direction d4 until the position of the moveable rail 10. Then path p2 changes direction so as to extend horizontally in direction d2 inside moveable rail 10 until loop L2. Here, path p2 again changes direction to turn back on itself and to extend horizontally in direction dl back to the end of the moveable rail 10 which it had entered. From here, path p2 extends downwards in direction d4 all the way to the bottom end of the assembly (or opening), at which end 422 of second elongate flexible member 42 is fixedly attached.

[0108] This routing of the elongate flexible members around paths pl and p2 allows the moveable rail 10 to be moved in both extension and retraction directions by operating a single drive shaft. When the drive shaft rotates in a first rotational direction, the elongate flexible members are driven around loops LI and L2 so as to pull moveable rail 10 downwards, by virtue of increased tension in the sections of the elongate flexible members between loops LI and L2 and ends 412 and 422. When the drive shaft is rotated in the opposite rotational direction, the moveable rail is moved upwards in direction d3, by virtue of increased tension in the sections of elongate flexible member between loops LI, L2 and ends 411, 421.

[0109] In order to cause the elongate flexible members to change direction when entering and leaving the ends of the moveable rail, end caps of the moveable rail may be provided which have guiding portions for causing the elongate flexible members to change direction according to the paths described above. Figure 12 shows a motor drive unit 51 and first and second elongate flexible members 41, 42, in an arrangement as schematically illustrated in figure 11, as viewed from the direction of movement of the moveable rail. Figure 12 shows end caps 13 and 14 of moveable rail 10 (not shown). As shown in figure 12, the end caps 13, 14 guide the elongate flexible members 41, 42, respectively, as they enter and exit the ends of the moveable rail 10. Figure 13 shows a perspective view of the first end cap 13 guiding the first elongate flexible member 41.

[0110] Attachment elements 93, 94 configured to attach ends of the first elongate flexible member to the first and second ends of the architectural opening, respectively, and to attach ends of the second elongate flexible member to the first and second ends of the architectural opening, respectively, are illustrated in figure 14. Figure 14 shows the routing of elongate flexible members 41, 42 in the arrangement schematically shown in figure 11. Attachment elements may comprise plugs for engaging with holes in a head rail for example.

[0111] Attachment elements may also comprise attachment feet which hold the end of an elongate flexible member, and are configured to be attached to an architectural opening, by screws for example.

[0112] Optionally, the retractable blind assembly further includes a mounting frame 90 as shown in figure 2. The ends of the first and second elongate flexible members 41, 42 may be fixedly attached to ends of the mounting frame, optionally using attachment elements 93, 94. The mounting frame of figure 2 includes the second rail 20 and side members extending from the top end to the bottom end of the opening, on either side of the covering 30. The side members may include guiding portions for guiding the movement of the moveable rail 10. Attachment elements 93, 94 may be configured to secure ends of the elongate flexible member to the second rail 20 and the bottom ends of the side members.

[0113] A mounting frame does not require a bottom frame member, as illustrated in figure 2. In other arrangements, a mounting frame may include the second rail 20, side members, and a third rail 21, as shown in figure 1.

[0114] As described above with reference to figures 6 to 10, the assembly may also include a track along which the translatable element is configured to translate. The track of the present example arrangement is arranged substantially similarly to the above description with respect to figures 7 and 8. As described with reference to figures 7 and 8, the track 70 may be provided beneath the translatable element 50. Alternatively, as illustrated in figure 15, clips 56 may be provided on the top of the translatable element, such that the translatable element is suspended from the track 70. In this arrangement, the translatable element 50 is upside down with respect to the translatable element shown in figures 4, 7 and 8.

[0115] Next a variation of the arrangement in which a translatable element including a motor drive unit is provided inside a moveable rail is described with reference to figure 16. The arrangement of figure 16 may be substantially identical to the arrangement described with reference to figures 11 to 15. However, in the arrangement of figure 16, a second moveable rail is provided. In this arrangement, rather than having a fixed second rail 20 as illustrated in figure 11, the covering 30 extends between the first moveable rail 10 and second moveable rail 15. First and second moveable rails 10, 15 may be independently moved in directions d3 and d4. The second moveable rail 15 may be configured exactly the same as the first moveable rail 10, with both moveable rails including a translatable element including a motor drive unit, with the motor drive unit including the first and second drive members as described herein. Alternatively, both moveable rails may have a motor drive unit, but only one of the moveable rails may have a translatable element.

[0116] In arrangements having two moveable rails, such as the arrangement shown in figure 16, the paths pl, p2 taken by elongate flexible members 41, 42 may be substantially as described with respect to figure 11. In particular, the retractable blind assembly may include attachment elements (as described above with reference to figures 11 to 15) configured to attach ends of the first elongate flexible member to the first and second ends of the architectural opening respectively, and to attach ends of the second elongate flexible member to the first and second ends of the architectural opening, respectively.

[0117] From the top of the assembly (or opening), path pl extends downwards in direction d4 until it reaches the position of second moveable rail 15. Then, path pl extends horizontally inside the second moveable rail 15, until it reaches a loop. At the loop, path pl changes direction to extend in direction d2, back to the end of the second moveable rail 15 which it had entered. Then, path pl exits the second moveable rail 15 and extends downwards in direction d4 to the position of the first moveable rail 10. Then, path pl extends horizontally inside the first moveable rail 10, until it reaches another loop. At this loop, path pl changes direction to extend in direction d2, back to the end of the first moveable rail 10 which it had entered. Then, path pl exits the first moveable rail 10 and extends all the way to the bottom end of the assembly (or opening). Path p2 is arranged in the same manner on the opposite side of the assembly (or opening).

[0118] The present disclosure is set forth in various levels of detail in this application and no limitation as to the scope of the claimed subject matter is intended by either the inclusion or non-inclusion of elements, components, or the like in the summary. In certain instances, details that are not necessary for an understanding of the disclosure or that render other details difficult to perceive may have been omitted. It should be understood that the claimed subject matter is not necessarily limited to the particular embodiments or arrangements illustrated herein.

[0119] The accompanying drawings are provided for purposes of illustration only, and the dimensions, positions, order, and relative sizes reflected in the drawings attached hereto may vary. The detailed description will be better understood in conjunction with the accompanying drawings, with reference made in detail to embodiments of the present subject matter, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the present subject matter, not limitation of the present subject matter. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the present subject matter. Thus, it is intended that the present subject matter covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0120] In the foregoing description, it will be appreciated that the phrases “at least one”, “one or more”, and “and / or”, as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. The term “a” or “an” entity, as used herein, refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein.

Claims

CLAIMS1. A retractable blind assembly, including: a moveable rail; a second rail; a covering extending between the moveable rail and the second rail; a first elongate flexible member routed along a first path and a second elongate flexible member routed along a second path; a drive member engaged with the first and second elongate flexible members such that rotating the drive member moves the moveable rail to retract or extend the covering; and a translatable element configured to translate in opposite first and second translation directions, perpendicular to the direction of movement of the moveable rail; wherein the translatable element includes the drive member, and the first path includes a first loop extending around the drive member and the second path includes a second loop extending around the drive member, such that the translatable element translating in the first translation direction increases a length of the first path and correspondingly decreases a length of the second path, and the translatable element translating in the second translation direction increases the length of the second path and correspondingly decreases the length of the first path.

2. The retractable blind assembly of claim 1, further including: a motor drive unit configured to move the moveable rail to retract or extend the covering.

3. The retractable blind assembly of claim 2, wherein the translatable element includes the motor drive unit.

4. The retractable blind assembly of claim 2 or 3, wherein the motor drive unit is configured to drive the first elongate flexible member around the first loop and drive the second elongate flexible member around the second loop in order to move the moveable rail so as to retract or extend the covering.

5. The retractable blind assembly of claim 4, wherein the motor drive unit includes a drive shaft, a motor configured to rotate the drive shaft, and the drive member, wherein the drive member is mounted on the drive shaft so as to rotate with the drive shaft, such that rotating the drive shaft drives the first and second elongate flexible members around the first and second loops, respectively.

6. The retractable blind assembly of claim 5, wherein the drive member includes first and second drive members.

7. The retractable blind assembly of claim 5 or 6, further including a battery for powering the motor, wherein the drive member is located between the motor and the battery.

8. The retractable blind assembly of any one of the preceding claims, wherein the first and second elongate flexible members are beaded chains, and the drive member includes first and second pulleys with teeth for engaging the beads of the beaded chains.

9. The retractable blind assembly of any one of the preceding claims, wherein the retractable blind assembly is configured such that, when installed in an architectural opening, the second rail is provided at a fixed location relative to the architectural opening, and the moveable rail moves downwards to extend the covering.

10. The retractable blind assembly of any one of claims 1 to 8, wherein the retractable blind assembly is configured such that, when installed in an architectural opening, the second rail is provided at a fixed location relative to the architectural opening, and the moveable rail moves upwards to extend the covering.

11. The retractable blind assembly of any one of the preceding claims, further including a track along which the translatable element is configured to translate,wherein the track is provided at a fixed location relative to the second rail, and the moveable rail is moveable between the second rail and the track.

12. The retractable blind assembly of claim 11, wherein both ends of the first elongate flexible member are coupled to the moveable rail, optionally to a first end of the moveable rail, and both ends of the second elongate flexible member are coupled to the moveable rail, optionally to a second end of the moveable rail opposite to the first end of the moveable rail.

13. The retractable blind assembly of claim 12, wherein both ends of the first elongate flexible member are fixed to a first traveller, both ends of the second elongate flexible member are fixed to a second traveller, and the moveable rail is detachably coupled to the first and second travellers.

14. The retractable blind assembly of any one of claims 11 to 13, wherein the first path includes a third loop extending around a first guide member and the second path includes a fourth loop extending around a second guide member, the first and second guide members provided at fixed locations relative to the second rail.

15. The retractable blind assembly of claim 14, wherein the first and second guide members are provided adjacent or within the second rail.

16. The retractable blind assembly of any one of claims 11 to 15, wherein the track constrains translation of the translatable element to only the first and second translation directions.

17. The retractable blind assembly of any one of claims 1 to 10, wherein the translatable element is provided within the moveable rail.

18. The retractable blind assembly of claim 17, whereinthe retractable blind assembly is configured such that, when installed in an architectural opening, the moveable rail is moveable between a first end and a second end of the architectural opening, and the retractable blind assembly further includes attachment elements configured to attach ends of the first elongate flexible member to the first and second ends of the architectural opening, respectively, and to attach ends of the second elongate flexible member to the first and second ends of the architectural opening, respectively.

19. The retractable blind assembly of claim 17 or 18, further including a mounting frame having first and second ends, with the moveable rail being moveable between the first and second ends of the mounting frame, wherein ends of the first elongate flexible member are fixed to the first and second ends of the mounting frame, respectively, and ends of the second elongate flexible member are fixed to the first and second ends of the mounting frame, respectively.

20. The retractable blind assembly of any one of claims 17 to 19, further including a track along which the translatable element is configured to translate, wherein the track constrains translation of the translatable element relative to the moveable rail to only the first and second translation directions.

21. The retractable blind assembly of any one of the preceding claims, wherein the first and second elongate flexible members extend in the direction of movement of the moveable rail on opposite sides of the covering.

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