WO2013034893A1

WO2013034893A1 - Modular portable screen apparatus

Info

Publication number: WO2013034893A1
Application number: PCT/GB2012/052152
Authority: WO
Inventors: Ian Dickson
Original assignee: Ian Dickson
Priority date: 2011-09-07
Filing date: 2012-09-03
Publication date: 2013-03-14
Also published as: GB2494430A; EP2753773A1; GB201115471D0; EP2753773B1

Abstract

A portable screen apparatus (10) has a screen (12) having a plurality of poles (14) and a plurality of panels (16, 18) extending between adjacent poles. The apparatus includes a plurality of base units (20), and each base unit may have a tank with a filling aperture (22). In one embodiment each base unit (20) has an end portion (30) with a convex perimeter portion (32) and a socket (24) adapted to receive one of the poles (14), the socket being substantially equidistant from points on the convex perimeter portion (32). When two base units (20) are placed with the convex perimeter portions (32) of the end portions (30) in contact, with the base units (20) at any chosen angle, the spacing between the two adjacent sockets (24) is a constant spacing (2R). The convex perimeter portion (32) may be shaped as part of a circle or a regular polygon. The screen includes a connecting panel (16) of a width (W1) equal to the constant spacing (2R), so that the connecting panel (16) fits exactly to bridge between the two adjacent base units (20). The invention provides a portable, lightweight and flexible screen apparatus suitable for use as a wind break or fence on all ground surfaces.

Description

Modular portable screen apparatus

This invention relates to a modular portable screen apparatus such as a screen or wind break of the sort used to provide shelter from the wind for people sat outdoors, for example in a garden, on a terrace, on a pavement outside a cafe, or on a beach, or to serve as a privacy or demarcation screen. The screen apparatus may also serve as a temporary or semi-permanent fence of the type used for construction projects and other events to control the safe and secure movement of pedestrians and vehicular traffic.

In particular it relates to a portable screen apparatus which can be erected on any surface without the need for specialist tools, but which is sufficiently stable to remain free standing under normal wind loads. Conventional wind breaks comprise a screen having a number of poles fixed in pockets in the screen. The wind break can be installed by driving the poles into the ground using a mallet or hammer. Although such wind breaks are well adapted to use on a beach or place of soft ground, they are not suitable for use on solid ground such as patios, terraces, pavements or timber decking.

It is known to provide screens on pavement areas outside cafes and restaurants, in order to provide visual screening of tables and chairs from other users of the pavement, to provide a boundary marker for the area of pavement being utilised by the restaurant, and to provide wind protection for customers sat at the tables. Such wind screens usually have metal posts with concrete or metal bases, and are therefore very heavy and not relatively portable. Such wind screens usually comprise two posts with a single panel of woven material supported between the posts. They do not provide flexibility of layout, and when two panels are used together there is often a gap between adjacent panels because the post bases extend around the posts and prevent the posts being placed immediately adjacent to each other. Such screens are relatively expensive. It is also known to provide temporary fencing to ensure a safe environment for pedestrians and vehicular traffic at various locations, and to provide a clear demarcation between safe and unsafe areas. Such known temporary fencing systems have support projections which protrude beyond the line of the temporary fence and can present a trip hazard to pedestrians and can obstruct wheeled apparatus such as wheelchairs.

It is an object of the present invention to provide a screen apparatus which overcomes at least some of the above disadvantages.

According to the present invention there is provided a portable screen apparatus comprising:

a screen comprising at least three panels and at least four poles, each panel extending between two adjacent poles; and

a plurality of base units, each base unit comprising an intermediate portion and two end portions arranged at opposite ends of the intermediate portion, wherein each end portion includes a socket adapted to receive one of said poles, the sockets in each base unit being spaced by a distance D, wherein at least one end portion has a convex perimeter portion adapted to contact a convex perimeter portion of an adjacent base unit, the socket in the end portion being substantially equidistant by distance R from a plurality of points on the convex perimeter portion, wherein at least one of said panels is a connecting panel having a width Wl, where Wl is substantially equal to 2R, and

wherein the two panels adjacent to the connecting panel are main panels each having a width W2, where W2 is substantially equal to D.

The panel having a width Wl is referred to as a connecting panel, and the panels either side of it having a width W2 are referred to as main panels. The screen may comprise three panels arranged main/connecting/main, for use with two base units. Alternatively the screen may comprise five panels arranged main/connecting/main connecting/main, for use with three base units. Alternatively the screen may comprise any odd number N of panels, for example 5, 7 or 9 panels, arranged with alternating main and connecting panels, with main panels at each end, for use with (N+l)/2 base units, for example 3, 4 or 5 base units. Each base unit may have a tank with a filling aperture. The filling aperture may be located on the upper surface of the base unit and may be provided with a filling cap. Optionally a drainage plug may be provided at the bottom of the base unit. The base unit may be filled with water, sand, gravel or similar in use, to increase the weight of the base unit. The base unit may be emptied for transport and/or storage.

Preferably each of the two end portions has a convex perimeter portion adapted to contact a convex perimeter portion of an adjacent base unit and a socket adapted to receive one of said plurality of poles, the socket being substantially equidistant from points on the convex perimeter portion. Each end portion may be a segment or section of a circular cylinder, with vertical side walls, so that the end portion of one base unit may abut with the end portion of another base unit to create a joint with a negligible air gap. Alternatively the side walls may be profiled such that the side wall of the end portion of one base unit can key or otherwise engage with the side wall of the end portion of another base unit.

In one embodiment the convex perimeter portion forms a circular arc in plan, the arc having a constant radius R. Two adjacent base units may then be placed at any angle to each other so that they are contiguous, with the sockets of adjacent units separated by distance 2R.

In another embodiment the convex perimeter portion forms part of a regular polygon in plan, the centre of each side of the polygon being at distance R from the socket. The polygon may be a hexagon, octagon or decagon, or a polygon with more or fewer sides. The polygon may have rounded or chamfered corners. Two adjacent base units may then be placed so that they are contiguous, with two sides of the two polygons adjacent to each other, and with the sockets of adjacent units separated by distance 2R.

The convex perimeter portion may extend through at least 180 degrees.

The end portions of the base unit may have a substantially uniform height such that when the base unit is placed on a horizontal surface the upper surface of each end portion is substantially horizontal. This ensures that the bottom edge of the screen can sit flush against the top surface of the end portions, to create a joint with a negligible air gap. The top and/or bottom edges of the screen can be provided with a stiffening means such as a keder edge or a thickened seam to stiffen the joint.

The upper surface of the intermediate portion on the line between the two sockets may be at substantially the same level as the upper surface of each end portion. This ensures that the bottom edge of the screen which extends between the two sockets can sit flush against the top surface of the base unit, to create a joint with a negligible air gap.

A first and a second of said plurality of base units may be arranged with a convex perimeter portion of a first end portion of the first base unit in contact with a convex perimeter portion of a first end portion of the second base unit, and wherein the connecting panel extends between one of said poles received in the socket at the first end portion of the first base unit and another of said poles received in the socket at the first end portion of the second base unit.

A first main panel may extend between the pole received in the socket at the first end portion of the first base unit and a pole received in the socket at a second end portion of the first base unit. A second main panel may extend between the pole received in the socket at the first end portion of the second base unit and a pole received in the socket at a second end portion of the second base unit. Each pole may be provided with a male threaded connector at its lower end. Each socket may be provided with a female threaded connector adapted to engage with the male threaded connector on the pole. However any suitable means of connecting the poles and sockets may be used, including push-pull fit connectors, twist-lock connectors, bolted or screwed connectors, click-fit connectors and the like.

The screen may be a fabric or plastic sheet screen comprising a plurality of tubular pockets, and each pole may be located in one of said tubular pockets. However any suitable means of fixing the poles to the screen may be used, including adhesives, heat welding, staples, nails or other fasteners and the like.

Alternatively the screen may comprise a plurality of rigid or semi-rigid panels, each panel being removably attached to the adjacent poles, for example by push-fit clip fasteners. The panels may be of any suitable rigid or semi-rigid material, for example plastic sheet material, polycarbonate, uPVC, polyethylene, wood, plywood, fibre board, composite board, metal sheet, rigid plastic foam board or corrugated sheet. Each tubular pocket may be provided with an opening at its lower end through which the pole extends. This enables the pole to be engaged in the socket.

Each tubular pocket may be provided with an opening at its upper end with a cross sectional area smaller than that of the pole. Each pole may be provided with a top connector at its upper end, which is accessible through the opening at the upper end of the tubular pocket.

The apparatus may comprise a plurality of top rails, each top rail being connectable to the top connectors of two adjacent poles. A top rail may be used in conditions where loads may be applied to the top of the wind screen, for example in restaurant use where a coat may be draped over the screen. The apparatus may comprise two interchangeable screens of different heights. Each pole may include a standard pole section and a pole extension piece connectable to the standard pole section to vary the height of the pole.

The standard pole section may include a top connector at its upper end. The pole extension piece may include a connector at its lower end adapted to connect to the top connector of the standard pole section. The top connector and the extension piece connector may be male and female connectors respectively, or vice versa.

Each pole may include a top cap which includes a connector at its lower end adapted to connect either to the top connector of the standard pole section or to the top connector of the pole extension piece. The top connector and the top cap connector may be male and female connectors respectively, or vice versa. Alternatively the pole may formed of a single section, and may include an integral top cap.

In a modified embodiment the base unit may be permanently filled with concrete, grout or other cementitious material. In another modified embodiment the tank and filling aperture of the base unit may be omitted, and the base unit may be formed as a solid base unit of concrete, grout or other cementitious material.

The invention will now be described by way of example only with reference to the drawings, in which: Fig. 1 is a side elevation of a screen apparatus according to the invention;

Figs. 2A and 2B are a plan view and a side elevation respectively of a base unit of the screen apparatus of Fig. 1;

Fig. 3 is a side elevation of a pole and rail of the screen apparatus of Fig. 1; Fig. 4 is a partial plan view of the rail of Fig. 3;

Fig. 5 is a side elevation of a fabric screen of the screen apparatus of Fig. 1; Figs. 6, 7 and 8 are plan views of different arrangements of screen apparatus according to the invention;

Figs. 9A and 9B are a plan view and a side elevation respectively of a base unit of another embodiment of a screen apparatus according to the invention;

Figs. 10A and 10B are a plan view and a side elevation respectively of a base unit of a further embodiment of a screen apparatus according to the invention;

Fig. 11 is a plan view of the screen apparatus of Figs. 9A and 9B; and

Fig. 12 is a plan view of the screen apparatus of Figs. 10A and 10B.

Fig. 1 shows a portable screen apparatus 10 according to the present invention. The apparatus comprises a screen 12 having a plurality of poles 14 and a plurality of panels 16, 18, each panel extending between two adjacent poles 14. In the example of Fig. 1 there is a single screen 12 and two base units 20, which are shown in Figs. 2A and 2B. Each base unit 20 includes a tank (not shown) with a filling aperture 22 and two sockets 24 each adapted to receive a pole 14. The base unit 20 may be formed of moulded plastic and the tank may comprise the hollow void inside the plastic moulding. However any suitable material may be used for the base unit 20, for example metal, wood, cementitious material etc. Each base unit 20 also includes two lifting handles 26, which may be formed as recesses in the upper surface of the base unit 20. Alternatively any other suitable form of lifting handle may be provided, for example a foldable handle which sits in a recess when not used, a cord handle, a projecting moulded handle or the like. The base units 20 may have a non- slip base, for example a corrugated bottom surface or a pad of high friction material adhered to the underside of the base unit 20.

The filling aperture 22 may be located on the upper surface of the base unit 20 and may be provided with a filling cap (not shown). Optionally a drainage plug may be provided at the bottom of the base unit 20. The base unit may be filled with water, sand, gravel or similar in use, to increase the weight of the base unit. The base unit 20 may be emptied for transport and/or storage, either by using the drainage plug (if fitted), or by tipping the base unit 20 and emptying the contents through the filling aperture 22.

As seen best in Fig. 2A each base unit 20 comprises an intermediate portion 28 and two end portions 30 arranged at opposite ends of the intermediate portion. Each end portion 30 has a convex perimeter portion 32 which forms a circular arc of radius R, centred on the corresponding socket 24 provided at the centre of the end portion 30.

In another embodiment of the invention, as shown in Figs. 9A and 9B, in which the same reference numerals are used to refer to elements which are similar to those illustrated in Figs. 2A and 2B, the convex perimeter portion 32 forms part of a regular polygon in plan, the centre of each side 33 of the polygon being at distance R from the centre of the socket 24. In the embodiment of Fig. 9A the polygon is a hexagon, while in the embodiment shown in Figs. 10A and 10B the polygon is a hexagon,. However it is to be understood that the polygon may have any number of sides, for example 4, 5, 6, 7, 8, 9, 10 or more sides. The polygon may have rounded or chamfered corners.

In the illustrated example of Figs. 2A and 2B the perimeter portion 32 comprises a vertical side wall, and the arc extends for more than 270^° in plan. However the width of the intermediate portion 28 can be increased, so that the arc extends for an angle between 180^° and 270^°, or it can be decreased, so that the arc extends for an angle of more than 270^°.

In the illustrated example the end portion 30 is a segment of a circular cylinder, with vertical side walls 32, so that the end portion 30 of one base unit 20 may abut with the end portion 30 of another base unit 20 to create a joint with a negligible air gap, as shown in Fig. 1. Alternatively the side walls 32 of the end portions may be profiled such that the side wall 32 of the end portion 30 of one base unit 20 can key or otherwise engage with the side wall 32 of the end portion 30 of another base unit 20 (not illustrated).

The end portions 30 of the base unit 20 have a uniform height, typically about 200 mm, so that when the base unit 20 is placed on a horizontal surface the upper surface 34 of each end portion 30 is substantially horizontal. This ensures that the bottom edge 40 of the screen 12 can sit flush against the top surface 34 of the end portions 30, to create a joint with a negligible air gap. The bottom edge 40 of the screen 12 is stiffened with a keder edge or a thickened seam so that the panels 16, 18 of the screen 12 sit flush against the top of the base unit 20 and do not flap excessively under wind load.

The upper surface 36 of the intermediate portion 28 is also at the same level as the upper surface of each end portion, so that all the panels 16, 18 sit flush against top of the base unit 20. If required the intermediate portion 28 can have a shaped upper surface 36 which tapers downward from the centre line which extends between the two sockets 24, so that is only the centre line which is at substantially the same level as the upper surface 34 of each end portion 30. The bottom edge of the panel 18 which extends between the two sockets 24 at opposite ends of the base unit 20 only extends along the centre line, so if the centre line is at the appropriate level, the panel 18 can sit flush against the top surface 36 of the intermediate portion 28, to create a joint with a negligible air gap. The base unit 20 may be shaped to permit stacking of the base units for storage when not in use. For example, the lower surface of the base unit 20 may include a recess (not shown) which engages with a projecting portion (not shown) on the upper surface 36.

In the example illustrated in Fig. 1 the screen comprises three panels 16, 18. The central panel or connecting panel 16 has a width Wl measured between the centres of the poles 14 at each side of the panel 16, where Wl is substantially equal to 2R, and where R is the radius of the perimeter 32 of the end portion 30 of the base unit 20. R may typically be between 100 and 350 mm, for example 200 mm, and Wl may typically be between 200 and 700 mm, for example 400 mm. When two base units 20 are placed in end to end abutment with each other, as in Figs. 1 and 6, the distance between the adjacent sockets 24 of the two adjacent end portions 30 is equal to 2R. Hence the internal poles 14 on either side of the central panel 16 can engage in the sockets 24 so that the panel 16 is held in a vertical plane by the two internal poles 14 without sagging.

The two end panels or main panels 18 either side of the central panel 16 each have a width W2 measured between the centres of the poles 14 at each side of the panel 18, where W2 is substantially equal to the spacing D between the two sockets 24 in each base unit 30. Dimensions D and W2 may typically be between 600 and 1500 mm, for example 1100 mm. The two external poles 14 can engage in the sockets 24 of the two remote end portions 30, so that each end panel 18 is held in a vertical plane by an internal pole 14 and an external pole 14 without sagging.

The invention is not limited to a screen apparatus having two base units 20 and a screen with three panels arranged in the following order: main panel 18; connecting panel 16; and main panel 18. The screen apparatus may comprise three base units 20, as illustrated in Fig. 7, with five panels arranged in the following order: main panel 18; connecting panel 16; main panel 18; connecting panel 16; and main panel 18. The screen apparatus may comprise any odd number N of panels arranged with alternating main panels 18 and connecting panels 16, with main panels 18 at each end, for use with (N+l)/2 base units. Fig. 8 illustrates an embodiment with seven panels 16, 18 and four base units 20.

The base units 20 and the screen 12 are readily portable, but when assembled provide a stable and windproof screen structure, which can be arranged in a variety of configurations. The convex perimeter 32 of the end portions 30 of the base units 20 permits the base units to be arranged in contact with each other at any angle, so that the screen apparatus can be arranged to follow a chosen line. This provides a very flexible system for the user. The base units can be positioned at right angles to each other to form right angle corners, or they can even be positioned to provide reverse angles.

Each pole 14 is provided with a male threaded connector 50 at its lower end, which in the example of Fig. 3 is a tapered connector. Each socket 24 is provided with a corresponding female threaded connector adapted to engage with the male threaded connector 50 on the pole, so that the pole 14 can be readily engaged with the base unit 20 by simple rotation of the pole 14. However any suitable means of connecting the poles 14 and sockets 24 may be used, including push-pull fit connectors, twist-lock connectors, bolted or screwed connectors, click-fit connectors and the like. The connector 50 and socket 24 should ensure a strong joint and vertical alignment of the pole 14.

The screen 12 is a fabric screen comprising a plurality of tubular pockets 42 defining the vertical edges of the panels 16, 18, and each pole 14 is located in a tubular pocket 42. The fabric of the screen 12 may be a woven or non-woven plastic or textile sheet, such as canvas or woven polyester or a plastic film, or a coated fabric, such as a PVC coated polyester weave. The fabric may be a stretch fabric which can easily be tensioned, such as a spandex or elastane material, so that the panels 16, 18 are lightly tensioned in the horizontal direction when the poles 14 are fixed in the base units 20. The pockets may be formed by stitching or any other suitable method. Instead of using pockets 42, the poles 14 may be fixed directly to the screen 30 by any suitable fixing method, for example adhesives, heat welding, staples, nails or other fasteners and the like.

In the illustrated example each tubular pocket 42 is provided with an opening at its lower end through which the bottom of the pole 14 extends. This enables the pole 14 to be engaged in its corresponding socket 24.

Each tubular pocket 42 is provided with an opening at its upper end with a cross sectional area smaller than that of the pole. This ensures that the top of the pocket is supported by the pole, since the pole 14 cannot slide through the upper opening, but it allows the addition of a top cap 56. In the illustrated example the top of each pole 14 has a top connector in the form of a pole socket 58 which is adapted to receive a plug 60 provided on the top cap 56. The socket 58 is accessible through the opening at the upper end of the tubular pocket 42.

Referring to Fig. 3, each pole comprises a standard pole section 52 and a pole extension piece 54 connectable to the standard pole section 52 to vary the height of the pole. This allows the screen apparatus to include two screens 12 of different height, for example a lower screen of 800 mm height and a higher screen of 1200 mm height. If the lower screen 12 is used, the poles 14 are used without the extension piece 54. If the higher screen 12 is used, the poles 14 are used with the extension piece 54. The extension piece 54 includes a pole socket 58 and plug 60 to allow it to be connected to the standard pole section 52 and the top cap 56. The pole socket 58 and plug 60 may be threaded connectors, or they may or include push- pull fit connectors, twist-lock connectors, bolted or screwed connectors, click-fit connectors and the like. The position of the pole socket 58 and plug 60 may be reversed, so that the socket 58 is on the cap 56 and the plug 60 is on the extension piece 54. It is to be understood that the poles 14 may be formed as a single piece, and that the separate top cap 56 may be omitted. The poles 14 may be of plastic, coated or uncoated hollow metal tubes, wood, fibreglass, composite or any other suitable material.

The apparatus of the invention may include optional top rails 70, as illustrated in Figs. 3 and 4. Each top rail can be connected between two adjacent poles 14. Any suitable form of connector may be used, but in the illustrated example each end 72 of the top rail 70 is provided with an aperture 74 through which the plug 60 of the top cap 56 can fit in order to secure the top rail 70 between the top cap 56 and the pole 14. If desired, top rails 70 can be provided only for fixing above the main panels 18. In this case the top rails 70 all have a length between apertures 74 of W2. Alternatively top rails 70 of length Wl between apertures 74 can also be provided on the connecting panels 16, so that each intermediate pole 14 has the ends 72 of two top rails 70 connected to it. The connector at the end 72 of each top rail 70 can be of any shape, for example a flattened shape to facilitate the connection of two top rails 70 to one pole 14. Top rails 70 may be used in conditions where loads may be applied to the top of the screen apparatus 10, for example in restaurant use where a coat may be draped over the screen 12, or to provide a portable screen apparatus 10 having a more solid appearance.

The embodiments of Figs 9 to 12 function in exactly the same way as the

embodiment of Figs 2 to 8, and parts which are the same are not described further. The only difference is that adjacent base units 20 are placed so that they are contiguous, with two sides 33 of the two polygons adjacent to each other and in contact with each other, so that the sockets 24 of adjacent units are separated by distance 2R measured between the centres of the sockets 24. Fig. 11 shows four base units 20 as illustrated in Figs. 9A and 9B placed next to each other. It can be seen that there are a limited number of angles at which two base units 20 can be placed relative to each other, depending on the number of sides 33 of the polygon. In the example of Fig. 11, in which the polygon is a hexagon, adjacent units can be placed at angles of 60°, 120°, 180°, 240° and 300°. This is in contrast to the embodiment of Fig. 2, where the convex perimeter portion 32 is not a polygon but a circle, and where adjacent base units can be placed at any angle relative to each other. There are circumstances where it is desirable to limit the variation in angle between adjacent base units 20, for example where the screen is required to be fixed in a strict linear or geometrical arrangement, and in such circumstances a polygonal base unit offers advantages.

Fig. 12 shows four base units 20 as illustrated in Figs. 10A and 10B placed next to each other. It can be seen that there are still a limited number of angles at which two base units 20 can be placed relative to each other, but in the case of Fig. 12 the polygon is a decagon, and so adjacent units can be placed at angles of 36°, 72°, 108°, 144°, 180°, 216°, 252°, 288° and 324°.

Although the invention has been described with the screen comprising fabric panels 16, 18, 118 attached to the poles 14 by inserting the poles 14 into pockets 42 in the panels, any suitable means of fixing the poles 14 to the screen may be used, for example adhesives, heat welding, staples, nails or other fasteners and the like.

In an alternative embodiment the screen may comprise a plurality of rigid or semirigid panels 16, 18, 118, each panel being removably attached to the adjacent poles, for example by push-fit clip fasteners, resilient U-shaped clips or snap connectors (not shown). The panels 16, 18, 118 may be of any suitable rigid or semi-rigid material, for example plastic sheet material, polycarbonate, uPVC, polyethylene, wood, plywood, fibre board, composite board, metal sheet, rigid plastic foam board or corrugated sheet. The invention according to all aspects provides a portable screen apparatus which is quick and easy to assemble, since the base units 20, 120 can readily be placed in position where required and the poles 14 then inserted into the sockets 24 to assemble the screen. It is lightweight, since the mass which gives the system its stability can be added after the base units are in position. It can be manufactured relatively inexpensively, for example by using plastic mouldings for the base units. It is portable and so can be easily stored when not in use. It can be easily moved to suit particular requirements, for example a change in wind direction, or to provide a screen at an angle to the wind direction. It is flexible in layout, allowing the user to arrange adjacent panels at chosen angles while still providing a continuous screen without sagging. It can be used both on soft surfaces, such as grass or a beach, as well as on hard surfaces, such as paving or timber decking. The poles and screen can be separated from the base units so that the base units can be left in situ while the poles and screen are stored away. It can be arranged in a continuous non-linear structure, which improves stability against lateral wind loading. It does not require projecting portions which act as a trip hazard for pedestrians or as an obstruction for wheelchairs.

Although the invention has been described with reference to example dimensions, the invention is not to be limited to these dimensions, and the screen apparatus may be supplied in any suitable size. The dimensions of the base unit are chosen to provide sufficient ballast weight when filled, so that horizontal wind load on the screen is resisted by the weight of the base unit, thereby preventing tipping of the screen apparatus. The pockets 42 may be dimensioned to provide play between the pole 14 and the pocket 42 so that the screen apparatus can accommodate differences in base level.

Claims

1. A portable screen apparatus comprising:

a plurality of base units, each base unit comprising an intermediate portion and two end portions arranged at opposite ends of the intermediate portion, wherein each end portion includes a socket adapted to receive one of said poles, the sockets in each base unit being spaced by a distance D, wherein at least one end portion has a convex perimeter portion adapted to contact a convex perimeter portion of an adjacent base unit, the socket in the end portion being substantially equidistant by distance R from a plurality of points on the convex perimeter portion,

wherein at least one of said panels is a connecting panel having a width Wl, where Wl is substantially equal to 2R, and

2. A portable screen apparatus according to claim 1, wherein each base unit has a tank with a filling aperture.

3. A portable screen apparatus according to claim 1 or 2, wherein each of the two end portions has a convex perimeter portion adapted to contact a convex perimeter portion of an adjacent base unit and a socket adapted to receive one of said plurality of poles, the socket being substantially equidistant from points on the convex perimeter portion.

4. A portable screen apparatus according to any of claims 1 to 3, wherein the convex perimeter portion forms a circular arc in plan, the arc having a constant radius R.

5. A portable screen apparatus according to any of claims 1 to 3, wherein the convex perimeter portion forms part of a regular polygon in plan, the centre of each side of the polygon being at distance R from the socket.

6. A portable screen apparatus according to any preceding claim, wherein the convex perimeter portion extends through at least 180 degrees.

7. A portable screen apparatus according to any preceding claim, wherein the end portions of the base unit have a substantially uniform height such that when the base unit is placed on a horizontal surface the upper surface of each end portion is substantially horizontal.

8. A portable screen apparatus according to claim 7, wherein the upper surface of the intermediate portion on the line between the two sockets is at substantially the same level as the upper surface of each end portion.

9. A portable screen apparatus according to any preceding claim, wherein a first and a second of said plurality of base units are arranged with a convex perimeter portion of a first end portion of the first base unit in contact with a convex perimeter portion of a first end portion of the second base unit, and wherein the connecting panel extends between one of said poles received in the socket at the first end portion of the first base unit and another of said poles received in the socket at the first end portion of the second base unit.

10. A portable screen apparatus according to claim 9, wherein:

one of said main panels extends between the pole received in the socket at the first end portion of the first base unit and a pole received in the socket at a second end portion of the first base unit; and

the other of said main panels extends between the pole received in the socket at the first end portion of the second base unit and a pole received in the socket at a second end portion of the second base unit.

11. A portable screen apparatus according to any preceding claim, wherein each pole is provided with a male threaded connector at its lower end, and wherein each socket is provided with a female threaded connector adapted to engage with the male threaded connector on the pole.

12. A portable screen apparatus according to any preceding claim, wherein the screen is a fabric screen comprising a plurality of tubular pockets, and each pole is located in one of said tubular pockets.

13. A portable screen apparatus according to claim 12, wherein each tubular pocket is provided with an opening at its lower end through which the pole extends.

14. A portable screen apparatus according to claim 12 or 13, wherein each tubular pocket is provided with an opening at its upper end with a cross sectional area smaller than that of the pole, and wherein each pole is provided with a top connector at its upper end.

15. A portable screen apparatus according to claim 14, wherein the apparatus further comprises a plurality of top rails, each top rail being connectable to the top connectors of two adjacent poles.

16. A portable screen apparatus according to any preceding claim, wherein the apparatus comprises two interchangeable screens of different heights, and wherein each pole includes a standard pole section and a pole extension piece connectable to the standard pole section to vary the height of the pole.