BUILDING STRUCTURE FRAMEWORK FOR PROTECTING STAGE STRUCTURE

Abstract: A building structure framework for supporting a sheet material covering comprises a main structure (A) having a generally rectangular floor plan and being constituted by a plurality of generally parallel arches (1) which extend at right-angles to an axis of symmetry of the floor plan. Each arch (1) is constituted by a plurality of interconnected girders (4, 5, 6) comprising a pair of leg girders (4) for supporting the arch on a horizontal surface, and at least four identical main girders (5).

Description: BUILDING STRUCTURE FRAMEWORK FOR PROTECTING STAGE STRUCTURE This invention relates to a building structure framework for supporting a sheet material covering, and to a building structure constructed in this manner. Nowadays, there is an increased need for portable or temporary stages for open-air entertainment such as pop concerts, performances by travelling repertory companies, etc. The stages for such structures come in five standard sizes having usable widths of 15m, 18m, 21m, 25m and 29m. In order to protect performers from the elements, such stages are provided with open-ended building structures. Because of the relatively large number of stage widths, and also because the stages can have differing depths, this entails the provision of a large number of building structures, many of which need to be specially made for a given event. The present invention provides a building structure framework for supporting a sheet material covering, the framework comprising a main structure having a generally rectangular floor plan and being constituted by a plurality of generally parallel arches which extend at right-angles to an axis of symmetry of the floor plan, wherein each arch is constituted by a plurality of interconnected girders comprising a pair of leg girders for supporting the arch on a horizontal surface, and at least four identical main girders. Each arch may be provided with two secondary girders, each secondary girder being connected between two of the main girders of that arch. In a preferred embodiment, the framework further comprises an end section constituted by an arch and a plurality of arch sections, the arch of the end structure being positioned generally parallel, and adjacent to, an arch of the main structure, and each of the arch sections being identical to one half of an arch. The framework may further comprise an overhanging section at the other end of the main structure, the overhanging section being constituted by a single arch having a pair of leg girders and at least four main girders interconnected together, the two main girders adjacent to the leg girders being angled away from the main structure so that the top of said arch is spaced away from the top of the adjacent arch of the main structure by a distance which is greater than that separating the leg girders of those two arches. In one particular arrangement, each of the arches is constituted by a pair of leg girders and ten identical main girders, and the end section has an arch and seven arch sections, In a second particular arrangement, each of the arches is constituted by a pair of leg girders, four identical main girders, and two secondary girders, the two secondary girders having a first predetermined length, and the end section has an arch and three arch sections. In a third particular arrangement, each of the arches is constituted by a pair of leg girders, four identical main girders and two secondary girders, each secondary girder having a second predetermined length, and the end section has an arch and four arch sections. In a fourth particular arrangement, each of the arches is constituted by a pair of leg girders, six identical main girders, and two secondary girders, each of the secondary girders having a third predetermined length, and the end structure section has an arch and four arch sections. In a fifth particular arrangement, each of the arches is constituted by a pair of leg girders, eight identical main girders, and two secondary girders, each of the secondary girders having a fourth predetermined length, and the end section has an arch and five arch sections. Advantageously, each of the girders is a compound braced girder, that is to say a girder constituted by inner and outer parallel booms braced together by a series of cross-pieces lying at angles of substantially 45° to the booms. The booms may be aluminium tubes of generally rectangular cross-section. Preferably, adjacent girders are connected together by means of respective knuckle joints associated with the ends of the two booms of each of said girders. The invention also provides a building structure constituted by a building structure framework as defined above and a sheet material covering. Advantageously, each pair of adjacent arches is provided with a strip of sheet material, the edge portions of each strip being connectable to the girders of said arches. The girders of the arches may be adapted to receive the edge portions of the strips in a slidable manner. Preferably, each pair of adjacent arch sections is provided with a strip of sheet material, the girders of the arch sections being adapted to receive the edge portions of the strips in a slidable manner. Advantageously, the outer booms of each arch or arch section are provided with a single, continuous anchor section formed with grooves for receiving the edges of said strips. Preferably, each of the outer booms is provided with a pair of outwardly-extending flanges, the flanges of the outer booms of a given arch or arch section being adapted to receive the anchor section associated with that arch or arch section. Several forms of building structure, each incorporating framework constructed in accordance with the invention, will now be described, by way of example, with reference to the drawings, in which:- Figure 1 is a perspective view of a first form of building structure; Figure 2 is a side elevation of the building structure of Figure 1; Figure 3 is a schematic plan view of the building structure of Figure 1; Figure 4 is a side elevation of an arch forming part of the framework of the building structure of Figure 1 ; Figure 5 is a cross-section taken on the line V-V of Figure 4; Figure 6 is an enlarged side elevation of the part P of the arch of Figure 4, and shows means for connecting parts of the arch together; Figures 7a to 7d are schematic plan views showing second, third, fourth and fifth forms of building structure; and Figure 8 is a side elevation of one arch of the fifth form of building structure. Referring to the drawings, Figures 1 to 3 show a stage SI and a first form of building structure which is constituted by a framework covered by sheet material. The stage SI is the smallest of the five standard stage sizes, that is to say it has a usable width of 15m. The framework has a main body section A, a domed rear end section B and an overhanging front section C. The main section A is constituted by three arches 1, the domed end section B is constituted by an arch 1 and three arch sections 2, and the overhanging end section C is constituted by an arch 3. Each of the arches 1 has a span of 15m, and is constituted by a pair of leg girders 4, four main girders 5 and two secondary girders 6. The secondary girders 6 are symmetrically positioned, and each is situated between a respective pair of main girders 5. Each of the girders 4, 5 and 6 is a compound-brace girder, that is say it has a front boom 7 and a rear boom 8 braced together by means of braces 8a which criss-cross the two booms at angles of 45°. The booms 7 and 8 and the braces 8a are aluminium tubes. The booms 7 and 8 each have a generally rectangular cross-section as shown. The girders 5 all have a length of 3.27 metres, the girders 6 have a length of 2.034 metres, and the girders 4 have a height of 3.650 metres. The booms 7 of each pair of adjacent girders are connected together by means of a respective knuckle joint (see Figure 6). Similarly, the booms 8 of each pair of adjacent are connected together by means of a respective knuckle joint of this type. Thus, as shown in Figure 6, two adjacent booms 7 are connected together by a knuckle joint constituted by aluminium knuckle castings 7a and 7b. The knuckle casting 7a is constituted by a pair of D-shaped parallel knuckles which interdigitate with a pair of D-shaped parallel knuckles of the knuckle casting 7b. A pin 7c, which passes though aligned apertures in the knuckles, completes the knuckle joint, so that the booms 7 can pivot relative to one another. The domed end section B is constituted by three arch sections 2, each of which is identical to one half of an arch 1, that is to say it is constituted by a leg girder 4, a pair of main girders 5 and a secondary girder 6, the secondary girder being positioned between the two main girders. The arch 3 of the front section C is identical to each of the arches 1 , except that the main girders 5 adjacent to the leg girders 4 are angled forwardly by 25°, best shown in Figure 2. As shown in Figure 5, each boom 7 is provided with an anchor section 9 which is a sliding fit within a pair of outwardly-extending flanges 10 formed on the outside surface of the boom. The anchor section 9 defines a pair of grooves 11 having access openings which face in opposite directions. Similarly, the booms 7 and 8 are formed on their inside surfaces with respective pairs of outwardly-extending flanges 10 to receive the ends of the braces 8a. Each pair of adjacent arches 1 of the main body section A is provided with a strip of polyvinyl chloride coated woven fabric 12. Similarly, strips 13 of this material are provided at the ends B and C of the structure between adjacent arch members, and a strip 14 is provided between the rear arch 1 of the main body section A and the arch 1 of the domed end section B. Each strip 12 to 14 is provided, at each lateral edge thereof, with beading 15 which can be slid into the grooves 11 of the anchor sections 9 (see Figure 5). Thus, the strips 12 to 14 can be slid into position, so as to cover the entire area between respective arches 1 or arch members. In order to stretch the material of the strips 12 to 14 for the purpose of increasing the strength of the finished structure, each strip has a width which is slightly less than the width between the corresponding arches or arch members. Also, the ends of each strip 12 to 14 are connected to the corresponding arches 1 or arch members so as to be under tension longitudinally. The provision of the anchor sections 9 assists with the standardisation of the structure, in that the booms 7 and 8 are all of the same cross-section. Thus, the strips 12 to 14 can be fixed to the arches and arch sections without having to provide special boom sections to receive the headings 15. Moreover, by providing the booms 7 of each arch or arch section with a single, continuous anchor section 9, any water that enters its grooves 11 , runs down the grooves to the ground, and so cannot gain access to the interior via the joints between the girders. Figure 7a shows a stage S2 and a second form of building structure. The stage S2 is the second smallest of the five standard stage sizes, that is say it has a usable width of 18m. The building structure is similar to that of Figures 1 to 5, in that it has a main body section A, a domed rear end section B and an overhanging front section C. Moreover, the main section A is constituted by three arches 21, the domed end section B is constituted by an arch 21 and four arch sections 22, and the overhanging end section C is constituted by an arch 23. Each of the arches 21 has a span of 18m, and is constituted by a pair of leg girders 4, four main girders 5 and two secondary girders 26. The secondary girders 26 are symmetrically positioned, and each is situated between a respective pair of main girders 5. As with the first form of building structure, each of the girders 4, 5 and 26 is a compound-braced girder. The girders 5 all have a length of 3.27m, and the girders 4 have a height of 3.650m. Each of the arch sections 22 of the domed end section B is identical to one half of an arch 21. Similarly, the arch 23 of the front section C is identical to each of the arches 21, except that the main girders 5 adjacent to the leg girders 4 are angled forward by 25°. The building structure shown in Figure 7b has a span of 21m, and is intended for use with a stage S3 which is the third smallest of the five standard stage sizes, that is to say it has a usable width of 21m. This structure is similar to the first form of structure, but each of its arches 31 is constituted by a pair of leg girders 4, six main girders 5 and two secondary girders 36. The leg girders 4 and the main girders 5 are identical to those of the earlier embodiments. The girders 26 are symmetrically positioned, and are fixed to the main girders 5 which are fixed to the leg girders 4. The domed end section B of this building structure has an arch 31 and four arch sections 32. each of which is identical to one half of an arch 31. The building structure shown in Figure 7c has a span of 24m, and is intended for use with a stage S4 which is the second largest of the five standard stage sizes, that is to say it has a usable width of 24m. This structure is similar to the first form of structure, but each of its arches 41 is constituted by a pair of leg girders 4, eight main girders 5, and two secondary girders 46. The leg girders 4 and the main girders 5 are identical to those of earlier embodiments. The domed end section B has an arch 41 and five arch sections 42, each of which is identical to one half of an arch 41. Finally, the building structure in Figure 7d has a span of 29m, and is intended for use with a stage S5 which is the largest of the five standard stage sizes, that is to say it has a usable width of 29m. This structure is similar to the first form of structure, but each of its arches 51 is constituted by a pair of leg girders 4, and ten main girders 5. The leg girders 4 and the main girders 5 are identical to those of earlier embodiments. The domed end section B is constituted by an arch 51 and seven arch sections 52, each of which is identical to one half of an arch 51. It will be apparent, therefore, that all five of the standard stage sizes can be constructed using a small number of basic components, namely the leg girders 4, the main girders 5 and the secondary girders 6, 26 and 36. The building structure of Figures 7d and 8 can be considered to be the basic structure, in that it uses only two basic components, namely two leg girders 4 and ten main girders 5. The other four building structure frameworks use basically the same components, but replacing two or more of the main girders with a pair of special girders for each building structure.

Claims: Claims 1. A building structure framework for supporting a sheet material covering, the framework comprising a main structure having a generally rectangular floor plan and being constituted by a plurality of generally parallel arches which extend at right- angles to an axis of symmetry of the floor plan, wherein each arch is constituted by a plurality of interconnected girders comprising a pair of leg girders for supporting the arch on a horizontal surface, and at least four identical main girders. 2. A building structure framework as claimed in claim 1, wherein each arch is provided with two secondary girders, each secondary girder being connected between two of the main girders of that arch. 3. A building structure framework as claimed in claim 1 or claim 2, further comprising an end section constituted by an arch and a plurality of arch sections, the arch of the end structure being positioned generally parallel, and adjacent to, an arch of the main structure, and each of the arch sections being identical to one half of an arch. 4. A building structure framework as claimed in claim 3, further comprising an overhanging section at the other end of the main structure, the overhanging section being constituted by a single arch having a pair of leg girders and at least four main girders interconnected together, the two main girders adjacent to the leg girders being angled away from the main structure so that the top of said arch is spaced away from the top of the adjacent arch of the main structure by a distance which is greater than that separating the leg girders of those two arches. 5. A building structure framework as claimed in any one of claims 1 to 4, wherein each of the arch is constituted by a pair of leg girders and ten identical main girders. 6. A building structure as claimed in claim 5, wherein the end section has an arch and seven arch sections. 7. A building structure framework as claimed in any one of claims 2 to 4, wherein each of the arches is constituted by a pair of leg girders, four identical main girders, and two secondary girders, the two secondary girders having a first predetermined length. 8. A building structure framework as claimed in claim 7 when appendant to claim 3, wherein the end section has an arch and three arch sections. 9. A building structure framework as claimed in any one of claims 2 to 4, wherein each of the arches is constituted by a pair of leg girders, four identical main girders and two secondary girders, each secondary girder having a second predetermined length. 10. A building structure as claimed in claim 9 when appendant to claim 3, wherein the end section has an arch and four arch sections. 1 1. A building structure framework as claimed in any one of claims 2 to 4, wherein each of the arches is constituted by a pair of leg girders, six identical main girders, and two secondary girders, each of the secondary girders having a third predetermined length. 12. A building structure framework as claimed in claim 1 1 when appendant to claim 3, wherein the end section has an arch and four arch sections. 13. A building structure framework as claimed in any one of claims 2 to 4, wherein each of the arches is constituted by a pair of leg girders, eight identical main girders, and two secondary girders, each of the secondary girders having a fourth predetermined length. 14. A building structure framework as claimed in claim 13 when appendant to claim 3, wherein the end section has an arch and five arch sections. 15. A building structure framework as claimed in any one of claims 1 to 14, wherein each of the girders is a compound braced girder, that is to say a girder constituted by inner and outer parallel booms braced together by a series of cross-pieces lying at angles of substantially 45° to the booms. 16. A building structure framework as claimed in claim 15, wherein the booms are hollow aluminium tubes of generally rectangular cross-section. 17. A building structure framework as claimed in claim 16, wherein adjacent girders are connected together by means of respective knuckle joints associated with the ends of the two booms of each of said girders. 18. A building structure framework substantially as hereinbefore described with reference to, and as illustrated by, Figures 1 to 6 Figure 7a, Figure 7b, Figure 7c, or Figures 7d and 8 of the drawings. 19. A building structure constituted by a building structure framework and a sheet material covering, the building structure framework being as claimed in any one of claims to 1 to 18. 20. A building structure framework as claimed in claim 19, wherein each pair of adjacent arches is provided with a strip of sheet material, the edge portions of each strip being connectable to the girders of said arches. 21. A building structure framework as claimed in claim 20, wherein the girders of the arches are adapted to receive the edge portions of the strips in a slidable manner. 22. A building structure as claimed in any one of claims 19 to 21 when appendant to claim 3, wherein each pair of adjacent arch sections is provided with a strip of sheet material, the girders of the arch sections being adapted to receive the edge portions of the strips in a slidable manner. 23. A building structure as claimed in claim 21 or claim 22 when appendant to claim 15. wherein the outer booms of each arch or arch section are provided with a single, continuous anchor section formed with grooves for receiving the edges of said strips. 24. A building structure as claimed in claim 23, wherein each of the outer booms is provided with a pair of outwardly-extending flanges, the flanges of the outer booms of a given arch or arch section being adapted to receive the anchor section associated with that arch or arch section. 25. A building structure substantially as hereinbefore described with reference to, and as illustrated by, Figures 1 to 6, Figure 7a, Figure 7b, Figure 7c, or Figures 7d and 8 of the drawings.

Inventors: WEMYSS GEORGE, WEMYSS, GEORGE
Applicants: ORBIT UK SERVICES LTD, WEMYSS GEORGE, ORBIT (UK) SERVICES LIMITED, WEMYSS, GEORGE
Application year: 2000
Main classification: E04H15
IPC codes: E04H15