AU2005211684A1 - Support Structure For A Screen - Google Patents

Description

P001 Section 29 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: Support Structure For A Screen The following statement is a full description of this invention, including the best method of performing it known to me: SUPPORT STRUCTURE FOR A SCREEN c FIELD OF THE INVENTION aThe invention relates to the field of portable or non-permanent outdoor screens. In particular, the invention relates to an improved support structure for c 5 said screens.

BACKGROUND TO THE INVENTION oo There is an increasing demand for opaque structures which can be used to prevent physical and or visual access by unauthorised persons to a c predetermined area. This need may arise, for example, where an organisation wishes to utilise an open and otherwise public space for a private function; where C an otherwise open public sporting field is to be temporarily used for a "ticket only" purpose; or where a military organisation wishes to prevent visual access ("counter observation") to a temporary or semi-permanent military operations area, among other things.

For may such applications, particularly where the counter observation function is anticipated to be temporary, it is necessary that these structures can be transported, erected and dismantled with relative ease and without the need for specialised equipment, while nevertheless providing an effective counter observation barrier, which may be up to four meters in height.

Temporary, or semi-permanent, counter observation screens which have been used to date tend to suffer from one of two shortcomings. Since an effective counter observation screen needs to be relatively tall, support structures for such screens are often quite heavy, necessitating the use of cranes or other equipment to both transport and erect such structures. They also require considerable time and labour during erection and dismantling due to the quite heavy and complicated structures which need to be employed to successfully maintain an erect screen.

One way which has been used in an attempt to overcome this kind of deficiency is to provide aluminium poles mounted into ground holes, which are specifically provided for this purpose, while suspending the screen material between the poles. However, this kind of solution is not always appropriate, particularly where no such pre-arranged ground holes are provided, or where the screen is to be used as a rapidly deployable counter observation measure for a 6 highly mobile military unit. Any saving which can be made in the weight and

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i complexity of the structure for transport purposes, in the complexity and number of parts involved, for purposes of rapid and reliable deployment, or in the ability of the structure to be deployed in all terrains and any position of choice without need S 5 for extensive site preparation, for purposes of rapid deployment, would provide a great advantage over existing prior art systems.

oo Alternatively, those known prior art systems which are relatively light and easy to deploy tend not to ultimately work very effectively as counter observation N screens. For example, it is quite common that continuous screening is not actually achievable throughout the structure. For example, prior art systems often i involve a "gap" between the screening material and the support structure, through which the "private" area may in fact be observed. Such screens also tend to have relatively low strength and wind resistance, often making them unreliable in practice.

Therefore, it is an object of the present invention to provide a-support structure for a counter observation screen, and a counter observation screening system, which is relatively portable, able to be deployed in a wide variety of positions, relatively simple to erect, but which nevertheless effectively screens visual access up to a height of four meters. In this regard, it will be noted that effective screening of visual access will not be understood to mean absolute visual impenetrability, but is a practical definition entailing that any person who does seek visual access to the screened area will be required to do so in a manner which would inevitably draw attention to themselves, for example by scaling a four meter ladder adjacent the screen, or by damaging the screening material in some way.

SUMMARY OF THE INVENTION According to the invention there is provided an elongate support member for use in a support structure for a screen made from flexible screen material, said support member being adapted to receive one or more elongate rolls of said screen material, wherein said support member is a visually impenetrable beam whose sectional configuration defines an open W-shaped or M-shaped profile, said profile including: Stwo first roll-housing channels extending parallel with and along the beam

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cand being open at a front side of the beam, and adapted to receive said elongate rolls; and and intermediate ridge disposed between and partly defining said first S 5 channels and extending parallel with and along the beam, said ridge equally and covertly defining a second channel which is open at a rear side of the beam.

00 The advantage of this structure is that it provides a high degree of strength from a relatively simple and easy to manufacture profile. It also allows a screen i structured to be constructed which is effectively visually impenetrable, as no gaps 0 10 occur at the anchoring point of the screen material to the support structure.

N Another advantage of this structure is that the there-channel profile allows the beam to be attached to auxiliary support basis at a variety of different points on the profile, depending on the most appropriate construction for the overall screen structure.

A further advantage to this kind of structure is that it possesses sufficient strength, particularly across the width of the beam, to resist the large tensile forces which may be applied when deployed in vertically supporting a tensioned fabric screen of up to four metres in height.

The roll-receiving channels are designed to receive rolls of the screening material, said screening material then intended to extend outward from said rolls, beyond the outer wall of said roll-receiving channels and toward the next support member in a series of such members comprising a screen structure.

Preferably, the height of said intermediate ridge is approximately half of the depth of the two roll-receiving channels. It has been found that this particular embodiment provides a good level of overall strength of the section, while allowing the necessary clearance to allow structural bolts to be fitted to the ridge without endurably hinging on the position of rolls of fabric inserted in the rollreceiving channels.

Advantageously, the profile of said being is symmetrical about the centre of said intermediate ridge. This further enhances the strength of the beam, as well as simplifying the manufacture of same.

Further advantageously, the terminal ends of said profile are rounded to facilitate the smooth transit of screen material across said ends, and to improve the strength of said beam.

A preferred method of manufacture of the beam according to the invention is roll forming, from a flat-plate steel blank. This method of construction is relatively cost effective, and provides a strong and durable structure for the beam.

Alternatively, it is possible to manufacture the beam by a pressing operation.

Preferably, said blank is initially 600mm wide and between 1 mm and 3mm thick. A beam according with the above dimensions is likely to be strong enough to be pile driven into the ground, as a simple method of erection of a screen, if desired.

An alternative method of manufacture of the beam according to the invention is to extrude the profile directly in aluminium.

Preferably, the profile of said roll-housing channel is defined by flat rear wall connected to said intermediate ridge and connected to a flat outer side wall by a bevelled return wall. The bevelled corners provide additional stiffening folds to the rear face of the beam. This configuration also provides a V-shaped cavity which may more securely contact and axially deflected roll of screen material when placed under tension.

This configuration also allows a front and rear strut of equal length to be fitted either fore or aft of the beam, as part of a beam support structure.

Advantageously, the profile of said roll-housing channel is further defined by flat outer side wall having a terminal end, wherein said terminal end features a rounded return surface. Preferably this rounded return surface is provided by a terminal fold of the steel material. Such a fold provides further stiffness to the outer section of the beam and provides for snag-free passing of the screen material across the end of the beam as it is extended toward the next beam in the support structure.

In another aspect of the invention, there is provided a screen structure, including: two elongate roll cores; a sheet of opaque flexible screen material, whose ends are anchored at said roll cores and are capable of being rolled up around said roll cores thereby forming a roll of screen material; and first and second support structures as defined above, each further including header and footer anchoring members and being fixed at a predetermined distance from one another; wherein said roll cores are anchored to said support members at said header and figure members and are located within adjacent roll-housing channels respectively of said first and second support structures; and wherein said screen N 5 material extends intention from a shed point on the outer periphery of the roll located in said roll-housing channel of the first said support structure, via contact 0 with the immediately adjacent terminal end of the profile of said first support structure, towards said second support structure, via contact with the immediately c adjacent terminal end of the profile of said second support structure, to a shed 0 10 point on the outer periphery of the roll located in said roll-housing channel of the N second said support structure, thereby to create a visually impenetrable screen.

The above represents a particularly advantageous embodiment of a support structure for a screen, which takes advantage of the various superior properties of the structural support member described above. In particular, it will be noted that this arrangement, when viewed from the rear, or closed, side of the beam is visually impenetrable, in that the support structure itself is visually impenetrable and the opaque screening material emerges from behind said structure, and extends to the next support structure in a series of such structures.

Effectively therefore, there is no "gap" which may be seen through by a casual observer.

In a particularly preferred embodiment of the screen structure, the roll cores are sufficiently flexible that they will deform axially so as to allow the outer surface of said rolls to make frictional contact with the inner surface of said rollhousing channels when said screen material is placed in tension. Effectively, the tension in the screen causes the roll cores to bend in a manner which causes them to bend towards the walls of the channel and frictionally "jam" on said channel wall. This allows the screen material to be held tightly in place. In particular, it is preferred that the axes of rotation of the roll cores, where not subjected to tension, are coplanar with terminal or "innermost" surface of the intermediate ridge. The reason for this is that where this part of the ridge is to be used as an anchor point for a brace, the bracing will accordingly be effectively anchored at a point equidistant from the front and rear points of the beam, Sallowing braces of equal length to the used, regardless of the side of the beam to

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cwhich they are anchored.

Particularly advantageously, is preferred that the screen material is rolled onto the roll core in a manner which would tend to cause the roll core to deform S 5 toward the outer wall of said roll-housing channels when said screen material is placed in tension.

o00 Effectively, this means that the material wound onto the roll core is oriented in such a way that when viewed from above by an observer facing the N open side of the beam, the roll on the left-hand channel, when unravelled towards the left would rotate in a clockwise direction, and the roll in the right-hand N channel, when unravelled towards the right would rotate in an anticlockwise direction. The reason for choosing such a configuration is that the roll core would then tend to deform towards, and jam frictionally against, the part of the channel wall which tends to provide the greatest frictional contact and therefore support for the roll.

Now will be described, with reference to a specific, non-limiting example, a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of a beam according to the invention.

Figure 2 is an orthogonal projection of the beam of Figure 1.

Figure 3 represents a combined plan, elevation and end elevation view of a beam adapted to form part of a screen structure according with the invention.

Figure 4 is a detailed view of the top and bottom ends of the beam of Figure 3.

Figure 5 is a cross-sectional view of part of the screen structure when in deployment as a screen according to the invention.

Figure 5a is the cross-sectional view of figure 5, showing exemplary dimensions of a preferred embodiment.

Figure 6 is a view of part of a screen structure in a partially installed position, illustrating one form of bracing structure which may be used.

Figure 7 is as per Figure 6, showing an alternative bracing structure.

O Figure 8 is a cross-sectional view of a component of the aluminium luff C pole which is used as a roll core for the screening material, as per the preferred embodiment of the invention.

Figure 9 is a plan and elevation view of a luff pole tensioner which may be c 5 used in conjunction with a luff pole formed from the component given in Figure 8, as per a preferred embodiment of the invention.

00 Figure 10 is an elevation view of a counter observation screen, as per a preferred embodiment of the present invention.

c Figure 11 shows a schematic plan view of two alternative arrangements of 0 10 twin beams for mounting a double-screen version of the invention.

c DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Turning first to Figure 1, there is shown a cross-sectional profile of a beam according to the present invention. The beam 5 is preferably formed via rollforming of a steel blank of width of approximately 600mm and thickness of between one to 3mm, depending on mass and strength requirements. The selection of a 600mm blank is preferable, as the standard commercially available steel sheet is approximately 1200mm wide, allowing two blanks to be cut from said sheet without waste.

Once folded, the overall width of the beam is about 280mm, and the depth is about 100mm.

The beam section is symmetrically formed about a central axis 10. The overall section or shape resembles a or depending on its orientation.

The shape forms two identical cavity or channel regions 15 which are capable of housing a luff pole, about which is wrapped flexible screening material (see Figure The channels 15 are defined by an outer wall 20, an inner wall 25 and a rear wall 30. The channels are separated by a central ridge 35 which is defined by a front wall 40 and two side walls 45. Said side walls correspond with the inner walls 25 of the channels. The ridge 35, on its obverse face defines a third channel 50. The channels 15 also feature a bevelled corner portion 55 and a beaded terminal portion The overall "folded" structure lends considerable strength to the material, in particular the beding at the terminal ends 60. The preferred grade of steel for the beam is 350 MPA. Alternatively, the beam may be constructed from Saluminium, and may be extruded in the form according to the invention, as

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N indicated in the diagrams.

Turning to Figure 2, it will be noted that the beam 5 is formed as an elongate continuous form having a cross-sectional structure as defined above. It will be further noted the advantageous inclusion of individual bolt-holes 65 in the front face of the central ridge, which will aid in the attachment of bracing oo structures, as detailed below. It is preferred that these bolt holes have a diameter of approximately 18mm and are spaced along the ridge at approximate centres of i 100mm.

Turning to Figure 3, there is shown a front and side view of a partially c constructed vertical support structure 70 according to the invention. Shown is a beam 5, with attached header and footer assemblies 75, 80. Anchored to said header and footer assemblies are two luff poles 85, formed from extruded aluminium components and having details as discussed below. The luff poles are attached to the header and footer plates 75, 80 via luff pole tensioners located at both top and bottom ends of said luff poles 85. The details of the luff pole tensioners 90 are given below.

Turning to Figure 4, there is given greater detail of the connection of the luff poles 85 into the header 75 and footer 80 sections of the vertical support structure 70, and of the anchoring arrangement connecting the footer 80 to the ground 95. It will be noted that the ground support structure 100 is depicted as a sunken concrete pier 105 with an anchoring plate 110. The pier 105 and the footer 80 are connected via a steel pedestal 115. The footer is anchored to the steel pedestal via a locking pin 120, about which the footer 80, and therefore the entire support structure 70, may pivot. This allows the whole structure to be readily 'laid flat' if circumstances require, such as high wind conditions or the need to rapidly deploy military assets toward the outside the screen. It also allows easier erection of the screen, allowing the screen to be assembled on the ground, and then 'pushed up' into position, potentially manually, prior to tensioning.

The luff poles 85 are anchored to the header 75 and footer 80 plates through holes in horizontal plates 125 connected to said header and footer. The luff poles themselves have tensioners 90 inserted into their ends. These luff pole tensioners feature legs 130 which are received in cavities 135 inside the luff poles 6 85 in a manner which does not allow free rotation of the tensioner inside the luff

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c pole. The tensioners 90 also feature a head 140 which protrudes from the luff pole 85, the head 140 featuring bolt holes 145, and a collar 150 which rests on the horizontal plate 125 of the header and footer.

S 5 The head 140 of the tensioner 90 is capable of being connected to a standard half-inch drive ratchet mechanism, which is used to rotate the luff pole 00 85 in a manner which would cause tightening of the screen material (not shown).

The screen is then held in tension by the insertion of a pin through the bolt holes i 145 of the tensioner 90 which prevents the luff poles 85 from rotating.

0 10 Dimensional detail of a preferred embodiment of the a tensioner according c-i to a preferred embodiment of the invention is given in figure 9.

It will also be noted that the header 75 and footer 80 are 'mirror images' of one another: this allows the beam 5 to be anchored at either end to the pedestal, and also allows the luff poles to be inserted 'either way up' into the header and footer plates 125. This contributes to the flexibility and ease of erection of the overall screen structure.

Turning to Figure 5, there is shown an assembled version of a screen structure according to the invention, which forms part of an overall screen, said screen comprising a series of such structures linked by a tensioned screening material. The structure features a beam 5, as per that described above, featuring two roll receiving channels 15, into which are inserted two rolls 155 of screening material. These rolls consist of a roll core 160, which equates to a luff pole as described above, to which is anchored a length of screen material 165. The screen material 165 is wound onto the roll core 160, as viewed in the diagram, in a manner which would cause the left-hand roll core to rotate in a clockwise direction as the roll material is unwound towards the right, and vice versa in relation to the left-hand roll core.

As the screen material 165 is extended toward the next structure in the series, it will be noted that it sheds from a shed point 170, travels tangentially towards, and makes contact with, the terminal end 60 of the beam structure, before extending away from the beam structure towards the next structure in the series.

8 When placed in tension in the manner described above, the screen cmaterial 165 will tend to cause the roll core 160 to deform, along its axis of rotation, towards the outer wall 20 of the roll-receiving channel 15 in the direction of the arrow 175. Once full tension is achieved, at least part of the rolled screen N 5 material 165 will be rendered in tight frictional contact with the outer wall 20 of the channel 15, thereby preventing further unravelling of the roll and effectively 0 locking the roll in place.

It will be observed that when viewed in the direction of the arrow 180, ie N from 'outside' the screened area, there is no 'gap' through which an observer may 10 detect visually what is occurring on the 'inside' of the screen structure.

N In relation to the roll core 160, it will be observed that this is effectively the luff pole 85. The luff pole is constructed from two hollow extruded aluminium members 185, of approximately hemispherical cross section, with an indent 190 in the centre of the flat face 195. These members are arranged with flat faces 195 abutting, forming an approximately spherical luff pole 85, having a central cavity 200. In this central cavity is inserted an end of the screen material 165. A number of bolts 205 are inserted through the cavity and through the end of the screen material, thereby anchoring it to the luff pole Turning the figure 5a, there is shown an example of the structure described above with reference to figure 5, indicating preferred dimensions for various parts of the structure. Figure 8 gives preferred dimensional detail of the luff pole member 185 described above.

There are a number of ways in which the screen support structure 70 may be secured in an upright position. Turning to Figure 6, there is depicted a bracing structure 210 which may be anchored in the ground 95 and attached at an upper portion of the beam 5. In this particular depiction, the beam 5 is showed equally anchored to the ground 95 via a sunken support pedestal 105. Equally, the lower end 215 of the bracing structure is also attached to a sunken pedestal 220.

Alternatively, as shown in Figure 7, an alternative form of adjustable telescoping brace 225 is shown. Such a brace may be used to allow flexibility in the brace arrangement where uneven ground is encountered. The support and bracing structure may be anchored in the ground via a conventional concrete pier, a screw-in pier or a duck bill system, as per those well known in the art.

SThe entire screen structure, consisting of a series of support structures as c described above, is shown in figures 10a and 10b, which depict the view of the a fence structure from inside and outside of the screened area, respectively.

If it is desired to erect a screen having a double or twin arrangement of c 5 screen material, of having a reinforced structure, the structure described above may be employed by mounting two adjacent sets of said structure. An indication oo of how this may be achieved is given in plan view in figure 11. A steel beam 230 is used to link two beams 5 according to the invention, via the intermediate c ridge/channel C 10 It will be appreciated by those skilled in the art that the foregoing is only c one manner in which the inventive concept may be put into effect. Other structural arrangements, materials of construction or construction methods may equally be applied, whilst remaining within the spirit and scope of the invention.

Claims (10)

1. 2. The support member of claim 1, wherein the height of said intermediate ridge is approximately half of the depth of said two first channels.
2. 3. The support member of any preceding claim, wherein the profile of said beam is symmetrical about the centre of said intermediate ridge.
3. 4. The support member of claim 3, wherein the terminal ends of said profile are rounded to facilitate the smooth transit of the screen material across said ends and to improve the strength of said beam. The support member of claim 1 or 2, wherein said beam is press-formed or roll-formed from a steel blank.
4. 6. The support member of claim 4, wherein said blank is 600mm wide and 1- 3mm thick.
5. 7. The support member of any of claims 1 to 4, wherein said beam is made from extruded aluminium. S8. The support member of any preceding claim, wherein the profile of said O c roll-housing channel is defined by a flat rear wall connected to said intermediate ridge and connected to a flat outer side wall by a bevelled return wall. N 9. The support member of claim 8, wherein the profile of said roll-housing channel is further defined by a flat outer side wall having a terminal end, wherein said terminal end features a rounded return surface. 0o An elongate support member for use in a support structure for a screen made from flexible screen material substantially as herein described with creference to the figures.
6. 11. A screen structure, including: two elongate roll cores; a sheet of opaque flexible screen material, whose ends are anchored at said roll cores and are capable of being rolled up around said roll cores thereby forming a roll of screen material; and first and second support structures as defined in any preceding claim, each further including header and footer anchoring members and being fixed at a predetermined distance from one another; wherein said roll cores are anchored to said support members at said header and footer members, and are located within adjacent roll-housing channels respectively of said first and second support structures; and wherein said screen material extends in tension from a shed point on the outer periphery of the roll located in said roll-housing channel of the first said support structure, via contact with the immediately adjacent terminal end of the profile of said first support structure, toward said second said support structure, via contact with the immediately adjacent terminal end of the profile of said second support structure, to a shed point on the outer periphery of the roll located in said roll- housing channel of the second said support structure, thereby to create a visually c impenetrable screen.
7. 12. The screen structure of claim 11, wherein the roll cores are sufficiently t'q C flexible that they will deform axially so as to allow the outer surface of said rolls to make frictional contact with the inner surface of said roll-housing channels when osaid screen material is placed in tension, thereby to substantially prevent rotation INO of said roll cores. S 13. The screen structure of claim 12, wherein the axes of rotation of said roll Scores, when not subjected to tension, are coplanar with the terminal surface of said intermediate ridge.
8. 14. The screen structure of claim 12, wherein the screen material is rolled on to the roll core in a manner which would tend to cause the roll core to deform toward the outer wall of said roll-housing channels when said screen material is placed in tension.
9. 15. A screen structure according to any one of claims 11 to 14, wherein said support structures are mounted pivotally on the ground.
10. 16. A screen structure substantially as herein described, with reference to the figures. DATED this 23rd day of September 2005 TOM WESTCOTT WATERMARK PATENT TRADE MARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN VIC 3122 P24547AUP00 CJs:ALH