SCREEN STRUCTURE

Abstract

A screen structure comprising: at least one support element comprising a bistable extendable member; a panel element attached to the at least one support element and comprising a leading edge, wherein the at least one support element and the panel element are configured to be rollable about a first longitudinal axis, to provide for extension and retraction thereof along a direction generally perpendicular to the first longitudinal axis between a first fully extended position and a second position where the at least one support element and the panel element are at least partially retracted; a handle element for extending and retracting the support element and the panel element upon application of a force to the handle element; and characterised by: at least one spacer element configured so that when the at least one support element and the panel element are in the second position, the leading edge of the panel element is substantially parallel with the first longitudinal axis.

Description

FIELD

The present disclosure relates to a screen structure.

BACKGROUND

Bistable extendable members, also referred to as “bistable reeled composites” (BRCs) and/or “split tube extendable members” (“STEMs”) and/or “split tubes” and/or “extendible sheet members” and/or “bistable composite elements”, are elements which are configurable between two stable forms: a rigid longitudinally extending structure, and a compact coil of flat rolled up material. In the compact coiled/rolled up form, a bistable extendable member can be rolled up/wound/coiled about a first axis. In the rigid longitudinally extending form, the bistable extendable member longitudinally extends straight along a second axis which is perpendicular to the first axis.

Bistability in a bistable extendable member arises as a result of the manipulation of the Poisson's ratio and isotropy in the various layers of material making up the bistable extendable member. Bistable extendable members can be made from fibre-reinforced composite materials, for example glass fibres in a thermoplastic matrix, which are consolidated under conditions of elevated temperature and pressure.

Due to their mechanical properties of being extendable and retractable again into a rolled up state, bistable extendable members can be useful in retractable structures such as retractable panels, screens, walls, dividers and/or partitions, such as those described in WO2019201948A1 and EP3251562B1.

WO8808620 describes an elongate element in the form of a longitudinally split tube. U.S. Pat. No. 6,217,975B1 describes an extendable sheet member which is configurable between first and second states. U.S. Pat. No. 6,602,574B1 describes an extendible, coilable member which is reversibly configurable between a coiled form and an extended form. WO9962811 describes a compound member formed from at least two extendible, coilable members, each of which is reversibly configurable between a coiled form and an extended form. U.S. Pat. No. 6,256,938B1 describes an elongate element in the form of a longitudinally split tube which is arranged to be progressively flattened and wound about an axis extending transversely to the longitudinal extent of the tube to form a coil.

The present disclosure seeks to alleviate, at least to a certain degree, the problems and/or address at least to a certain extent, the difficulties associated with the prior art.

SUMMARY

According to a first aspect of the disclosure, there is provided a screen structure. The screen structure comprises at least one support element comprising a bistable extendable member, a panel element attached to the at least one support element and comprising a leading edge, wherein the at least one support element and the panel element are configured to be rollable about a first longitudinal axis, to provide for extension and retraction thereof along a direction generally perpendicular to the first longitudinal axis between a first fully extended position and a second position where the at least one support element and the panel element are at least partially retracted, a handle element for extending and retracting the support element and the panel element upon application of a force to the handle element; and characterised by at least one spacer element configured so that when the at least one support element and the panel element are in the second position, the leading edge of the panel element is substantially parallel with the first longitudinal axis.

Advantageously, such a configuration means that the at least one support element and panel element will roll/wrap/coil and unroll/unwrap/uncoil about the first longitudinal axis without creasing/deforming the panel element. It is envisaged that the screen structure may be used in medical settings in which hygiene/cleanliness is of the upmost importance. Any creasing/deforming of the panel is undesirable as such areas are prime spots for the build-up of dust/dirt. The leading edge of the panel element is defined as the edge which the panel follows when the panel element and at least one support element are being extended. The leading edge is therefore the first part of the panel element to be extended and the last part of the panel element to be retracted. If a leading edge is not maintained parallel to the first longitudinal axis, the panel element may become creased/deformed as the panel element rolls/wraps/coils around the first longitudinal axis at different rates along the length of the first longitudinal axis. Alternatively, when the at least one support element and panel element are being extended/retracted, the panel element could fall out of the plane defined by a frame of the screen structure and flap as the at least one support element and panel element are being retracted/extended. This flapping of the panel element could result in damage to the screen structure by way of creases/deformation of the panel element caused by uneven rolling/wrapping/coiling and unrolling/unwrapping/uncoiling about the first longitudinal axis. In a first fully extended position, the panel element is completely unrolled/unwrapped/uncoiled from the first longitudinal axis, and the leading edge is as far as possible from the first longitudinal axis. In the second position, the support element and panel element are at least partially rolled/wrapped/coiled around the first longitudinal axis. This covers a situation whereby a portion of the at least one support element and panel element are rolled/wrapped/coiled around the first longitudinal axis and a portion of the at least one support element and panel element are extended. The second position also covers a situation whereby the at least one support element and panel element are fully retracted around the first longitudinal axis. When in the second position, at least a portion of the at least one support element and panel element will define a cylindrical roll about the first cylindrical axis. If a cross section of such a cylindrical roll was taken along a plane defined by the first longitudinal axis, the two edges of the resulting cylindrical roll would be substantially parallel with each other and the first longitudinal axis.

Optionally, the spacer element is sized so that the outer diameter of said at least one spacer element is greater than an inner diameter of the support element in a fully retracted position thereby enabling the leading edge of the panel element to be substantially parallel to the first longitudinal axis. Advantageously, this helps ensure that the leading edge of the panel element is maintained in a position parallel to the first longitudinal axis and is therefore able to roll and unroll about the first longitudinal axis evenly, preventing the panel element from creasing/deforming whilst rolling/unrolling about the first longitudinal axis. With a spacer element smaller than an inner diameter of the support element in a fully retracted position, the portion of the panel element rolling/wrapping/coiling around the spacer element is not adequately supported and so the panel element may roll/wrap/coil about the first longitudinal axis unevenly.

Optionally, the first longitudinal axis is defined by a rotor element and the at least one support element and panel element are attached to said rotor element. Advantageously, this provides a point about which the at least one support element and panel element may be rolled/wrapped/coiled.

Optionally, at least one spacer element of the screen structure comprises an inner surface configured to be positioned around a rotor element, the at least one spacer element further comprising a first connecting surface and a second connecting surface, both connecting surface defining a passageway connecting the inner surface of the spacer element to an outer surface of the spacer element. Advantageously, the passageway allows the spacer element to be widened so that it may be attached (slid or clipped on) to the rotor element. This reduces manufacturing costs by removing the need for an additional attaching means. The passageway serves a dual purpose; as well as allowing the spacer element to clip on to the rotor element, the passageway allows the panel element to pass through the passageway.

Optionally, the panel element is attached to said rotor element by means of least one fold in the panel element along an axis parallel to said first longitudinal axis which creates at least two sections of said panel element, wherein a part of at least one of said at least two sections of said panel element is attached to a part of said second section of said panel element, after said panel element has rolled around said rotor element. Advantageously, this can prevent the panel element moving out of a plane defined by the frame of the screen structure when the bistable extendable member and the panel element are being extended and increase the uniformity of the coil of the panel element around the rotor element. This also improves the ease of construction of the screen structure.

Optionally, the spacer element is positioned over the panel element attached to the rotor element such that a portion of the panel element passes through the passageway of the spacer element. Advantageously, by positioning the spacer element in such a manner, the panel element is further attached to the rotor element. The passageway defined by the two connecting surfaces of the spacer element allows the spacer element to clip over the panel element attached to the rotor element, and for the panel element to pass through the passageway.

Optionally, the at least one support element and panel element define a cylindrical roll when fully retracted about the first longitudinal axis and wherein a side profile of the cylindrical roll has 2 edges which are substantially parallel with each other and the first longitudinal axis.

Optionally, the panel element comprises a flexible polymer film material such as Polyethylene terephthalate.

Optionally, at least one support element is configured to define an upper edge of the panel element, and wherein the spacer element is positioned so as to engage a bottom edge of the panel element. Advantageously, by using only one bistable extendable member, the construction costs of a single screen structure can be reduced. By positing this support element at the top (i.e. upper edge) of the panel element, the panel element is encouraged to roll/wrap/coil and unroll/unwrap/uncoil in a manner which corresponds to the rolling/wrapping/coiling and unrolling/unwrapping/uncoiling of the bistable extendable member. A spacer element positioned to engage with a bottom edge of the panel element can further encourage this rolling/wrapping/coiling behaviour. Engaging with a bottom edge of the panel means that the spacer element comes in to connect with the bottom edge of the panel element i.e. this is the portion of the panel element which comes into contact with the spacer element and which is supported by the spacer element as it rolls/wraps/coils about the first longitudinal axis.

Optionally, the screen structure comprises one bistable extendable member. Advantageously, this reduces manufacturing costs.

Optionally, the outer surface of said spacer element is curved about the first longitudinal axis. Advantageously, this provides for even rolling of the panel element about the first longitudinal axis.

Optionally, the screen structure comprises two or more spacer elements positioned along the length of the first longitudinal axis. Advantageously, multiple spacer elements provide that the panel element may be supported at multiple points along the length of the first longitudinal axis. This may be beneficial in aiding with uniform rolling/wrapping/coiling of the at least one support element and panel element around the first longitudinal axis and ensuring that a leading edge of the panel element is maintained parallel to the first longitudinal axis. When multiple spacer elements are used in a screen structure, the diameter of such spacer elements may change depending on their proximity to the support element. Spacer elements closer to the support element will have an external diameter less than an external diameter of a spacer element positioned further from a support element. This ensures that, whilst still providing support for the panel element, the spacer elements do not cut into the panel element and cause creasing/deformation.

Optionally, the screen structure comprises a reinforcing layer along the bottom edge of the panel element. Advantageously, this gives the bottom edge of the panel additional weight which helps stabilise the panel element in the plane defined by the frame of the screen structure and thereby reduces movement of the panel element outside this plane during extension and retraction. The reinforcement also increases the depth of the panel element along the bottom edge which aids the bottom part of the panel element in wrapping/coiling and unwrapping/uncoiling in a manner corresponding to the wrapping/coiling and unwrapping/uncoiling of the bistable extendable member.

Optionally, the reinforcing layer is opaque. Advantageously, this provides a visual cue to the dimensions of the panel element.

Optionally, the panel element is directly attached to the handle element. Advantageously, this helps to prevent the panel element moving out of a plane defined by the frame of the screen structure.

Optionally, the handle element is attached to the leading edge of the panel element.

Optionally, the support element is attached to the panel element by means of a supporting layer. Advantageously, the use of a supporting layer prevents the panel element from wrinkling/deforming when it is rolled and unrolled about the first longitudinal axis.

Optionally, the supporting layer comprises Polyvinyl chloride.

Optionally, the panel element comprises struts generally parallel to said first longitudinal axis. Advantageously, the application of such struts may provide additional strength to the panel element.

Optionally, the panel element comprises folds generally parallel to said first longitudinal axis. Advantageously, the application of such struts may provide additional strength to the panel element.

Optionally, the screen structure is according to the first aspect of the disclosure.

Optionally, the screen structure includes any one or more of the optional features presented above in relation to the first aspect of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be carried out in various ways and examples of the disclosure will now be described by way of example with reference to the accompanying drawings, in which:

FIG. 1A (prior art) shows a perspective view of a bistable extendable member in a partially rolled up state;

FIG. 1B (prior art) shows a perspective view of the bistable extendable member of FIG. 1A in a fully rolled up state;

FIG. 1C (prior art) shows a perspective view of the bistable extendable member of FIG. 1A in a fully longitudinally extended state;

FIG. 2A (prior art) shows the cross-sectional profile of the bistable extendable member of FIG. 1A when it is in a rolled up state, as in FIG. 1B;

FIG. 2B (prior art) shows the cross-sectional profile of the bistable extendable member of FIG. 1A when it is in a longitudinally extended state, as in FIG. 1C;

FIG. 3A shows a front view of a screen structure in a fully extended position;

FIG. 3B shows a front view of the screen structure of FIG. 3A in a partially extended position;

FIG. 4A shows a rear perspective view of a screen structure in a fully extended position;

FIG. 4B shows a front perspective view of the screen structure of FIG. 4B in a partially extended position;

FIG. 5 shows a perspective view of a spacer element;

FIG. 6 shows a cross section view of a screen structure in a fully retracted position;

FIG. 7 shows a front view of a panel element with crease positions;

FIG. 8 shows a cross sectional view of a panel element wrapped around a rotor element;

FIG. 9 shows a cross sectional view of the same setup of FIG. 8, with the addition of a spacer element;

FIG. 10 shows a perspective view of a support element and panel element substantially fully retracted about a first longitudinal axis, without the presence of a spacer element.

FIG. 11 shows a perspective view of a bottom edge of the panel element with reinforcement.

DETAILED DESCRIPTION

FIG. 1A illustrates a bistable extendable member 1. The bistable extendable member 1 is configurable in a first state in which the bistable extendable member 1 is rolled up (i.e. coiled) about a first axis 2, and a second state in which the bistable extendable member 1 is longitudinally extended along a second axis 3 which is perpendicular to the first axis 2. As shown in FIG. 1A, the bistable extendable member 1 can be in both the first state and the second state at the same time when the bistable member is partially coiled up or extended. For example, a first portion 4 of the bistable extendable member 1 can be in the first coiled state, and simultaneously, a second portion 5 of the bistable extendable member can be in the second extended state, with a transition portion 6 between the first portion 4 and the second portion 5. In the examples discussed herein, the bistable extendable member 1 comprises a bistable composite split tube extendable member. However, it is also to be understood that any other bistable extendable member(s) may be employed, such as a non-composite bistable extendable member, or any other bistable reeled composite or bistable split tube extendable member.

FIG. 1B shows the bistable extendable member 1 when it is fully in the first state. That is, when the entire length of the bistable extendable member 1 is rolled up about the first axis 2. In this form, the first portion 4 of the bistable composite element 1 comprises the entire length of the bistable composite element 1, and there is no transition portion 6 or second portion 4. Conversely, FIG. 1C shows the bistable extendable member 1 when it is fully in the second state. That is, when the entire length of the bistable extendable member 1 is longitudinally extended along the second axis 3. In this form, the second portion 5 of the bistable composite element 1 comprises the entire length of the bistable composite element 1, and there is no transition portion 6 or first portion 4.

As shown in FIG. 2A, when the bistable composite element 1 is in the first state, i.e. in the first portion 4 of the bistable composite element 1, in a plane which is normal to the second axis 3, the bistable composite element 1 has a cross-sectional profile 7 which is substantially flat and straight. As shown in FIG. 2B, when the bistable composite element 1 is in the second state, i.e. in the second portion 5 of the bistable composite element 1, in a plane which is normal to the second axis 3, the bistable composite element 1 has a cross-sectional profile 8 which is C-shaped. That is, when the bistable composite element 1 is in the second state, it curves upwards at its longitudinal edges. This is also shown in FIGS. 1A and 1C.

An application of the bistable extendable member 1 described herein shall now be described, with reference to FIGS. 3A and 3B, which show a screen structure. In the screen structure 20, a bistable extendable member 1 is employed as an upper member 21a of a frame 21. Side members 21b and 21c of the frame 21 are provided by supports 22a and 22b respectively. Supports 22a and 22b may be aluminium, or other suitable material. A panel element 30 comprising a flexible polymer film (though panels of other materials such as other polymers and/or textiles may also be employed) is arranged to hang substantially flat in the plane defined by the frame 21 and may be attached to the upper member 21 directly, or via one or more zips, or via one or more intermediary supporting layers. The use of one or more intermediary supporting layers to attach the upper member to the panel allows the panel element and upper member to align themselves and hang in the same plane. Optionally, the intermediary support layer may comprise adhesive tape, and further may comprise Polyvinyl chloride (PVC). Optionally, the panel element may comprise PET. The supports 22a and 22b are each attached to a respective base support 40a and 40b. Optionally, the base supports 40a and 40b may be attached with a plurality of wheels 41 to make the structure moveable and portable. By means of the two states of the bistable composite element, the frame and thus also the panel can be progressively rolled up or extended, due to the bistable composite element, as described above in relation to the bistable composite element 1. FIG. 3A shows the structure and the panel in a fully extendable position and FIG. 3B shows the structure in a partially retracted position. In a fully extended position, the panel element is completely unrolled/unwrapped/uncoiled from the first longitudinal axis, and a leading edge is as far as possible from the first longitudinal axis. In the partially retracted position, the support element and panel element are at least partially rolled/wrapped/coiled around the first longitudinal axis. Once lifted, a pushing or pulling force can be applied to the support 22a or support 22b to cause the panel 30 to be retracted/rolled up/closed or extended/pulled out/opened respectively. The supports 22a and/or 22b as described herein may be referred to as being ‘handle elements’ in so far as, amongst other things, they function to allow a user to extend and retract the panel 30 once they have been picked one up, moved it and placed it on the ground in another location so as to extend or retract the panel (i.e. the supports 22a and/or 22b allow a user to extend or retract the panel 30 upon application of a force thereto).

FIGS. 4A and 4B show an alternative exemplary screen structure 50 which is mounted to a generally vertical wall 60. It is, though, envisaged that the screen structure 50 may be mounted to any other surface, such as a generally vertical post, or a piece of furniture. Alternatively, it is also envisaged that the screen structure 50 may be adapted to be freestanding i.e. not mounted to a surface such as a wall.

The screen structure 50 is generally similar to a screen structure 20 shown in FIGS. 3A and 3B, in that it comprises a bistable extendable member 1 and a panel 30. Though, instead of aluminium supports 22a and 22b (as in FIGS. 3A and 3B), an elongate handle element 51 and a spine element 52 may form a frame 53 together with the bistable extendable member 1, inside which the panel is 30 is arranged. The elongate handle element 51 and the spine element 52 may be formed of aluminium, or any other suitable metal or other material(s). The elongate handle element is generally parallel to a first longitudinal axis 54. The first longitudinal axis 54 is the longitudinal axis about which the panel element and support element are wrapped/coiled/rolled.

In the example shown, the spine element 52 comprises a generally straight elongate member having a generally rectangular cross-sectional profile. The spine element 52 is arranged to provide structural support and stiffness to the screen structure 50. Similarly, in the example shown, the handle element 51 comprises a generally straight elongate member having a generally square cross-sectional profile. A pushing or pulling force can be applied to the handle element 51 to cause the bistable extendable member 1 and the panel 30 to wrap/roll/coil and unwrap/unroll/uncoil respectively about the first longitudinal axis 54 and thereby cause the bistable extendable member and the panel element to retract and extend.

It is also envisaged that alternative shapes, sizes and configurations of handle elements and spine elements may alternatively be employed in the screen structure 50 other than those which are shown in FIGS. 4A and 4B and described below.

In the example shown, the handle element is attached to the panel element across the entire length of the leading edge of the panel element. The leading edge of the panel element is the edge of the panel element which is adjacent to the part of the screen structure that is moveable to enable the extension and retraction of the panel element and support element. For example, the handle element could be attached to the leading edge of the panel element across the entire length of the leading edge of the panel element. Attaching the panel to the handle across the entire length of the leading edge of the panel element has the advantageous effect that, whenever a pulling or pushing force is applied to the handle, this force is uniformly spread over the length of the panel element. If the panel element was attached to the handle element at only one location, the application of a force to the handle may result in the uneven distribution of that force into the panel element. Any uneven distribution of force may cause the panel element to roll/wrap/coil and unroll/unwrap/uncoil about the first longitudinal axis in an uneven manner. Such uneven rolling/wrapping/coiling and unrolling/unwrapping/uncoiling could result in undesired creases/deformations in the panel element and mean that the panel element may more easily move out of the plane defined by the frame. Such movement out of the place defined by the frame (or flapping) may cause damage to the screen structure by way of creases/deformation as the panel element rolls/wraps/coils and unrolls/unwraps/uncoils about the first longitudinal axis unevenly.

In either example, the screen structure may further comprise a rotor element 15 defining the first longitudinal axis 54 (see FIGS. 4A and 4B), about which the bistable extendable member 1 and panel element 30 are configured to roll/wrap/coil. The rotor element 15 may be made from aluminium, or any other suitable material. In the example shown, the rotor element 15 may be a straight elongate member having a generally circular cross-sectional profile. Alternatively, the rotor element may be any other suitable shape. In a direction of the first longitudinal axis 54, the rotor element 15 is at least as long as the length of the panel element 30 in a same direction so that the panel element 30 may be completely wrapped around the rotor element 15.

The bistable extendable member 1 employed as the upper member 21a of the frame 21 ensures that when the at least one support element and the panel element are substantially fully retracted about the rotor element, the external diameter of the portion of the panel element affixed to the support element is substantially the same as the external diameter of the support element (see FIG. 6). When the support element is substantially fully retracted around the first longitudinal axis, the rolled/wrapped/coiled support element has an outer diameter 17. At points on the first longitudinal axis not supported by a support element, the panel element rolls around the first longitudinal axis unassisted. Because of the smaller width of the panel element compared to the support element, the outer diameter of the fully retracted panel element would be much less than the outer diameter of the fully retracted support element 17. This could result in the panel element rolling/wrapping/coiling unevenly about the length of the first longitudinal axis and having a differing outer diameter along its length when fully retracted (see, for example, FIG. 10). To ensure that parts of the panel element not immediately attached to the support element roll/wrap/coil around the first longitudinal axis to define an outer diameter that is substantially the same as the outer diameter defined by the support element and that when the panel element and support element are fully retracted the leading edge of the panel element is substantially parallel to the first longitudinal axis, a spacer element is used (present, but not visible in FIG. 3A, 3B, 4A or 4B).

FIG. 5 shows a spacer element 10. The spacer element 10 has an inner surface 11 configured to be positioned about the rotor element 15. The inner surface 11 is curved with a curvature of radius which approximates the curvature of outer radius of the rotor element 15. The inner surface 11 of the spacer element 10 may be connected to an outer surface 12 of the spacer element 10 through a passageway defined by a first connecting surface 13 and a second connecting surface 14. The first connecting surface and second connecting surface may be rectangular. The outer surface of the spacer element may be smooth to prevent the panel element snagging on the outer surface when the panel element is wrapped thereabouts. A distance from the centre of the spacer element 10 to the inner surface 11 is less than a distance from the centre of the spacer element 10 to the outer surface 12. The outer surface has a constant curvature of radius around a first longitudinal axis. If the outer edge of the spacer element was completed i.e. the passageway was not defined, the spacer element would be circular. A diameter of this circle is referred to as the outer diameter of the spacer element. When the spacer element 10 is positioned on the rotor element 15, the effective diameter of the rotor element 15 is increased to that of the external diameter of the spacer element 10.

FIG. 6 shows a cross-sectional view of bistable extendable member 1 and a panel element 30 fully retracted around a rotor element 15 and a spacer element 10 positioned on a bottom part of the rotor element 15 to assist in the guiding of the panel element 30 around the rotor element 15. Preferably, the spacer element 10 is sized such that an outer diameter of the spacer element is greater than an inner diameter 16 of the retracted bistable extendable member 1. As the bistable extendable member rolls/wraps/coils around the first longitudinal axis, the outer diameter of the rolled/wrapped/coiled bistable extendable member increases more than the outer diameter of the rolled/wrapped/coiled panel element as the width of the bistable extendable member is greater than that of the panel element. The larger outer diameter of the spacer element compensates for this difference in width between the bistable extendable member and the panel element and helps the panel element to roll/wrap/coil evenly about the first longitudinal axis, ensuring that a leading edge of the panel element is parallel to the first longitudinal axis. When fully retracted, the outer diameter of the bistable extendable member 17 substantially corresponds to an outer diameter of the panel element rolled/wrapped/coiled around the spacer element 10 and a leading edge of the panel element is parallel to the first longitudinal axis. This corresponding rolling/wrapping/coiling of the bistable extendable member 1 and the panel element 30 about the rotor element 15 prevents uneven rolling and unrolling of the panel element 30 when the bistable extendable member 1 and panel element 30 are extended and retracted. If the spacer element 10 is incorrectly sized, portions of the panel element 30 rolling/wrapping/coiling about the spacer element 10 may roll/wrap/coil at a different rate to the bistable extendable member 1, meaning that the panel element 30 may unevenly roll and unroll when being extended and retracted and may consequently crease/deform.

As seen in FIG. 6, the spacer element 10 may be positioned at the bottom part of the rotor element 15 so that the effect of improving the even rolling/wrapping/coiling of the panel element 30 about the rotor element 15 is experienced along the length of the rotor element 15. Optionally, a spacer element 10 may be positioned at any other point along the length of the rotor element 15. Optionally, more than one spacer element 10 may be positioned along the length of the rotor element 15. Positioning multiple spacer elements 10 along the length of the rotor element 15 may help in maintaining an even rolling/wrapping/coiling of the panel element 30 about the rotor element 15 along its length and ensure that a substantially equal outer diameter is achieved across the length of the first longitudinal axis when the support element and panel element are substantially fully retracted and the leading edge of the panel element is parallel to the first longitudinal axis along the entire length of the first longitudinal axis. If multiple spacer elements 10 are positioned along the length of the first longitudinal axis, the spacer elements 10 positioned closer to the bistable extendable member 1 may have a smaller outer diameter than those spacer elements positioned further from the bistable extendable member. This prevents the spacer element applying unnecessary pressure to the panel element and prevents the panel element creasing/deforming upon contact with the spacer element. As the spacer elements move closer in position to the support element, their external diameter may approach the internal diameter of the support element.

The spacer element 10 may be attached to the rotor element 15 by a fastening means. Optionally, the design of the spacer element 10 itself may hold the spacer element 10 on the rotor element 15 without the need for further fastening means. The spacer element 10 may be designed such that a diameter of the inner surface is smaller than the outer diameter of the rotor element. By applying a force to temporarily increase the internal diameter of the spacer element, the spacer element may be affixed to the rotor element. When the force is removed, and the spacer element is allowed to return to its original shape, the spacer element may constrict about the rotor element and hold itself in position, thereby providing a ‘snap-on’ type attachment.

To aid with even rolling/wrapping/coiling of the panel element 30, the panel element 30 may be attached to the rotor element 15. By attaching the panel element 30 to the rotor element 15, a more even rolling/wrapping/coiling of the panel element 30 about the rotor element may be achieved. To attach the panel element 30 to the rotor element 15, the panel element 30 may be affixed to the outer surface of the rotor element 15 using an adhesive tape or other suitable attachment means. Alternatively, the panel element 30 may be configured to provide a means of attachment to the rotor element 15. FIG. 7 shows folds 35 along the length of the panel element 30 parallel to the first longitudinal axis 54. These folds 35 may be added during the manufacturing of the panel element 30 to create at least two portions of the panel element. Preferably, folds along the length of the panel element parallel to the first longitudinal axis create a first portion 31, a second portion 32, a third portion 33 and a fourth portion 34 of the panel element 30. As shown in FIG. 8, the panel element may be positioned so that the first portion 31 of the panel element extends substantially perpendicularly to the first longitudinal axis 54, the second portion 32 of the panel element wraps around the rotor element 15 and a third portion 33 of the panel element likewise extends perpendicular to the first longitudinal axis 54 and substantially parallel to a first portion 31 of the panel element. A suitable attachment means, for example, adhesive tape or glue, may be used to join the first portion 31 of the panel element to the third portion 33 of the panel element. The fourth portion 34 of the panel element, attached to the third portion 33 of the panel element will then be free to roll/wrap/coil around the rotor element 15 and will be the portion of the panel which may be extended and retracted.

In order to strengthen the panel element, the panel element 30 may optionally comprise vertical struts or folds which help to strengthen the panel element 30 without hindering the extension or retraction of the panel element about the first longitudinal axis 54.

FIG. 9 shows a cross sectional view of a spacer element 10 positioned on a rotor element 15 through a plane perpendicular to a plane defined by the first longitudinal axis, whereby the second portion 32 of the panel element 30 is rolled/wrapped/coiled around the rotor element 15 and positioned between the outer surface of the rotor element 15 and the inner surface 11 of the spacer element. The first portion 31 and the third portion 33 of the panel element which have been attached to each other may protrude through a passageway of the spacer element defined by the first connecting surface 13 and the second connecting surface 14. The fourth portion 34 of the panel element 30 extends from the passageway of the spacer element and is free to roll/wrap/coil around the spacer element 10. The rolling/wrapping/coiling of the panel element about the spacer element positioned on the rotor element may produce a different rolling/wrapping/coiling effect to the rolling/wrapping/coiler of the panel element around the rotor element without a spacer element.

FIG. 10 shows a support element and a panel element substantially fully retracted around a first longitudinal axis defined by a rotor element, without the presence of a spacer element. Because the support element comprises a bistable extendable member, the support element has a greater width than the panel element. As a result of this, the rolling/wrapping/coiling of the support element and the panel element about the first longitudinal axis may become uneven along the length of the first longitudinal axis. As the support element retracts and is rolled/wrapped/coiled about the first longitudinal axis, it is supported by itself, with each additional layer of support element resting against the previous layer. The portion of the panel element attached to the support element coils around the first longitudinal axis in a similar manner, owing to the support of the support member. The portion of the panel element not attached to the support element is not fully supported and, as such, may roll/wrap/coil irregularly around the first longitudinal axis. This can cause creasing/deformation of the panel element when extending and retracting the support element and panel element. When portions of the panel element are not adequately supported, the leading edge of the panel element is no longer parallel to a first longitudinal axis. The panel element and support element do not roll/wrap/coil around the first longitudinal axis to define a cylindrical roll, and the roll does not have edges which are parallel to each other and to the first longitudinal axis.

To further aid with the rolling/wrapping/coiling of the panel element 30, a reinforced layer 18 may be formed on the panel element 30. FIG. 11 shows a reinforced layer formed on the bottom edge 21d of the panel element. Such reinforcement can be provided, for example, by wrapping the panel element with adhesive tape, or another suitable material(s). Optionally, the reinforced layer may comprise two layers of adhesive tape. Such reinforcement of the bottom edge 21d of the panel element provides additional weight to the panel element 30 and aids in preventing the panel element moving out of the plane created by the frame during extension of the panel element. A reinforced bottom edge of the panel element 30 also aids in retraction of the panel element 30. The increased width of the panel element 30 provided by the reinforcement layer means that the diameter of the substantially fully retracted panel element 30 around the spacer element 10 more closely approximates the diameter of the substantially fully retracted bistable extendable member 1 and so aids in ensuring that the bistable extendable member 1 and the panel element 30 coil in a corresponding manner.

Various modifications may be made to the described embodiment(s) without departing from the scope of the invention as defined by the accompanying claims.

Claims

1. A screen structure comprising: at least one support element comprising: a bistable extendable member;a panel element attached to the at least one support element and comprising a leading edge,wherein the at least one support element and the panel element are configured to be rollable about a first longitudinal axis, to provide for extension and retraction thereof along a direction generally perpendicular to the first longitudinal axis between a first fully extended position and a second position where the at least one support element and the panel element are at least partially retracted;a handle element for extending and retracting the support element and the panel element upon application of a force to the handle element; andat least one spacer element configured so that when the at least one support element and the panel element are in the second position, the leading edge of the panel element is substantially parallel with the first longitudinal axis.

2. The screen structure as claimed in claim 1, wherein said at least one spacer element is sized so that the outer diameter of said at least one spacer element is greater than an inner diameter of the support element in a second position thereby enabling the leading edge of the panel element to be substantially parallel to the first longitudinal axis.

3. The screen structure as claimed in claim 1, wherein the first longitudinal axis is defined by a rotor element and the at least one support element and panel element are attached to said rotor element.

4. The screen structure as claimed in claim 3, wherein said at least one spacer element comprises an inner surface configured to be positioned around said rotor element, said at least one spacer element further comprising a first connecting surface and a second connecting surface, both connecting surfaces defining a passageway connecting said inner surface of said spacer element to an outer surface of said spacer element.

5. The screen structure as claimed in claim 3, wherein said panel element is attached to said rotor element by means of least one fold in the panel element along an axis parallel to said first longitudinal axis which creates at least two sections of said panel element, wherein a part of at least one of said at least two sections of said panel element is attached to a part of said second section of said panel element, after said panel element has rolled around said rotor element.

6. The screen structure as claimed in claim 4, wherein the spacer element is positioned over the panel element attached to the rotor element such that a portion of the panel element passes through the passageway of the spacer element.

7. The screen structure as claimed in claim 1, wherein said at least one support element and panel element define a cylindrical roll when substantially fully retracted about said first longitudinal axis and wherein a side profile of said cylindrical roll has 2 edges which are substantially parallel with each other and said first longitudinal axis.

8. The screen structure as claimed in claim 1, wherein said panel element comprises a flexible polymer film material.

9. The screen structure as claimed in claim 1, wherein said at least one support element is configured to define an upper edge of said panel element, and wherein said at least one spacer element is positioned so as to engage a bottom edge of said panel element.

10. (canceled)

11. The screen structure as claimed in claim 1 wherein said outer surface of said at least one spacer element is curved about the first longitudinal axis.

12. The screen structure as claimed in claim 1, comprising two or more spacer elements positioned along the length of the first longitudinal axis.

13. The screen structure as claimed in claim 1, wherein the screen structure comprises a reinforcing layer along a bottom edge of the panel element or is reinforced by a fold perpendicular to the first longitudinal axis.

14. The screen structure as claimed in claim 13, wherein said reinforcing layer is opaque.

15. The screen structure as claimed in claim 1, wherein said panel element is directly attached to said handle element.

16. The screen structure as claimed in claim 15, wherein the handle element is attached to the leading edge of the panel element.

17. The screen structure as claimed in claim 1, wherein the support element is attached to the panel element by means of a supporting layer.

18. The screen structure as claimed in claim 17, wherein the supporting layer comprises Polyvinyl chloride.

19. The screen structure as claimed in claim 1, wherein the panel element comprises struts generally parallel to said first longitudinal axis.

20. The screen structure as claimed in claim 1, wherein the panel element comprises folds generally parallel to said first longitudinal axis.