Lattice-form support beam and solar tracker having such a beam

Abstract

The invention relates to a lattice-form support beam having three side members that extend in parallel in a main direction of extension of the beam and are connected together by cross members and tie rods via securing plates secured to the side members. Each securing plate (8c) secured to a given side member (4) has two radial flat fins (11a, 11b), each comprising a securing orifice. The first fin (11a) is used to removably secure the ends of a first cross member (6), of a first tie rod (9a) and of a second tie rod (9b), which are secured to one another by a first single bolt system (14) passing through the securing orifice of the first fin. The second fin (11b) is used to removably secure the ends of a second cross member (7), of a third tie rod (9c) and of a fourth tie rod (9d), which are secured to one another by a second single bolt system (17) passing through the securing orifice of the second fin.

Claims

1. A lattice support beam of triangular cross section comprising: a set of three longitudinal members extending in parallel along a main direction of extent of the beam, a plurality of triangular assemblies distributed along the main direction of extent and each extending in a plane perpendicular to said main direction of extent, each triangular assembly being formed by three crossmembers mechanically connecting the longitudinal members in pairs, a plurality of tie rods each mechanically connecting the longitudinal members in pairs while extending between two consecutive triangular assemblies, a plurality of fastening plates fastened to the longitudinal members, each fastening plate fastened to a given longitudinal member among the three longitudinal members comprising a first flat flange and a second flat flange extending radially with respect to said given longitudinal member, the first flat flange forming a first fastening surface for the removable fastening of one end of a first crossmember among said plurality of crossmembers, of one end of a first tie rod and of one end of a second tie rod among said plurality of tie rods, and the second flat flange forming a second fastening surface for the removable fastening of one end of a second crossmember among said plurality of crossmembers, of one end of a third tie rod and of one end of a fourth tie rod among said plurality of tie rods, wherein the end of the first crossmember, the end of the first tie rod and the end of the second tie rod are fastened together by a single first bolting system comprising a fastening screw passing through one and the same fastening orifice of the first flat flange, and in that the end of the second crossmember the end of the third tie rod and the end of the fourth tie rod are fastened together by a single second bolting system comprising a fastening screw passing through one and the same fastening orifice of the second flat flange.

2. The lattice support beam as claimed in claim 1, wherein each fastening plate fastened to a given longitudinal member comprises a central surface matching the outer shape of said given longitudinal member, said first flat flange and said second flat flange laterally prolonging the central surface while extending radially with respect to the given longitudinal member.

3. The lattice support beam as claimed in claim 2, wherein each fastening plate is secured to the given longitudinal member by means of rivets at the central surface.

4. The lattice support beam as claimed in claim 1, wherein the end of the first crossmember is fastened to an inner face of the first flat flange, whereas the end of the first tie rod and the end of the second tie rod are fastened to an outer face of the first flat flange, and in that the end of the second crossmember is fastened to an inner face of the second flat flange, whereas the end of the third tie rod and the end of the fourth tie rod are fastened to an outer face of the second flat flange.

5. The lattice support beam as claimed in claim 4, wherein the end of the first tie rod and of the third tie rod, respectively, is in contact with the outer face of the first flat flange and the outer face of the second flat flange, respectively.

6. The lattice support beam as claimed in claim 5, wherein the end of the second tie rod and of the fourth tie rod, respectively, comprises a play-compensating device.

7. The lattice support beam as claimed in claim 1, wherein said one and the same fastening orifice of the first flat flange and of the second flat flange, respectively, is situated at the center of the first flat flange and of the second flat flange, respectively.

8. The lattice support beam as claimed in claim 1, wherein said set of three longitudinal members includes a lower longitudinal member, of a first upper longitudinal member and of a second upper longitudinal member, and each triangular assembly comprises an upper crossmember connecting the first upper longitudinal member to the second upper longitudinal member, a first lateral crossmember connecting the first upper longitudinal member to the lower longitudinal member, and a second lateral crossmember connecting the second upper longitudinal member to the lower longitudinal member, the first end and the second end of each upper crossmember of a given triangular assembly being fastened directly respectively to a first fastening plate of said plurality of fastening plates fastened to the first upper longitudinal member and to a second fastening plate of said plurality of fastening plates fastened to the second upper longitudinal member, the first end and the second end of each first lateral crossmember of said given triangular assembly being fastened directly respectively to the first fastening plate and to a third fastening plate of said plurality of fastening plates fastened to the lower longitudinal member, and the first end and the second end of each second lateral crossmember of said given triangular assembly being fastened directly respectively to the second fastening plate and to the third fastening plate.

9. The lattice support beam as claimed in claim 8, wherein the upper crossmembers and the first and second lateral crossmembers have the same length so as to obtain equilateral triangular assemblies, and in that the first flat flange and the second flat flange of each of the first, second and third fastening plates form between them an angle substantially equal to 60°.

10. The lattice support beam as claimed in claim 8, wherein the first and second lateral crossmembers have the same length so as to obtain isosceles triangular assemblies, and in that the first flat flange and the second flat flange of each of the first and second fastening plates form between them an angle substantially equal to 45°, in that the first flat flange and the second flat flange of the third fastening plate form between them an angle substantially equal to 90°.

11. A solar tracker comprising a lattice support beam as claimed in claim 9, said lattice support beam supporting a table of a solar tracker equipped with at least one solar energy collection device and resting on the first upper longitudinal member and on the second upper longitudinal member.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0052] The description given below with regard to the appended drawings, given by way of nonlimiting examples, will give a clear understanding of what the invention consists of and how it can be implemented. In the appended figures:

[0053] FIG. 1, already described above, shows an example of a known lattice support beam;

[0054] FIG. 2, already described above, illustrates an enlargement of a part of the lattice support beam of FIG. 1;

[0055] FIG. 3 shows two partial views (a) and (b) illustrating, from two different angles, an example of fastening tie rods and crossmembers to a fastening plate fastened to a lower longitudinal member of a lattice support beam, according to one possible embodiment of the present invention.

DESCRIPTION OF EMBODIMENT(S)

[0056] In the figures, and unless stated otherwise, elements which are identical or similar will bear the same reference signs.

[0057] As has been indicated above, the invention relates to a lattice support beam similar to the one shown in FIG. 1, the various common elements (longitudinal members 2, 3, 4 and crossmembers 5, 6 and 7 forming the triangular assemblies) of which will not be described again. In the following, only the modification made to the fastening plates according to the invention will be presented.

[0058] It is assumed in the following, in a nonlimiting manner, that the first and second lateral crossmembers 6, 7 described above all have the same length so as to obtain isosceles triangular assemblies. It will be recalled that, in this case, the first fastening plates 8a and the second fastening plates 8b, respectively fastened to the upper longitudinal members 2 and 3, must each comprise two flat flanges forming between them an angle substantially equal to 45°, whereas the third fastening plates 8c, fastened to the lower longitudinal member 4, must each comprise two flat flanges forming between them an angle substantially equal to 90°. Since the three fastening plates 8a, 8b and 8c differ in this case only in terms of the angle formed by the flat flanges, the description which follows will, for the sake of simplification, describe the principle of the invention for the fastening plate 8c.

[0059] Thus, FIG. 3 depicts two partial views (a) and (b) showing a fastening plate 8c fastened to the lower longitudinal member 4 of the lattice beam structure. The fastening plate 8c therefore replaces, according to the invention, the fastening plate 8c illustrated in FIG. 2.

[0060] As has been indicated above, the fastening plate 8c comprises a central surface 10 matching the outer shape of the longitudinal member 4 and two flat flanges 11a and 11b laterally prolonging the central surface 10 and extending radially with respect to the longitudinal member 4 while forming between them an angle substantially equal to 90°. The fastening plate 8c is secured to the longitudinal member preferably by means of four rivets 13 at the central surface 10. The first flat flange 11a forms a first fastening surface for the removable fastening of one end of a first crossmember, here the first lateral crossmember 6, of one end of a first tie rod 9a and of one end of a second tie rod 9b. The second flat flange 11b forms a second fastening surface for the removable fastening of one end of a second crossmember, here the second lateral crossmember 7, of one end of a third tie rod 9c and of one end of a fourth tie rod 9d among said plurality of tie rods.

[0061] However, unlike the plate 8c of FIG. 2 which comprises six through-holes 12, each flat flange 11a and 11b of the fastening plate 8c here comprises, according to the invention, a single fastening orifice, preferably situated at its center. Thus, as visible in FIG. 3, the end of the first crossmember 6, the end of the first tie rod 9a and the end of the second tie rod 9b are fastened together by a single first bolting system 14 comprising a fastening screw 15 passing through the fastening orifice of the first flat flange 11a, and a clamping nut 16. Similarly, the end of the second crossmember 7, the end of the third tie rod 9c and the end of the fourth tie rod 9d are fastened together by a single second bolting system 17 comprising a fastening screw 18 passing through the fastening orifice of the second flat flange 11b, and a clamping nut 19.

[0062] The ends of the crossmembers 6 and 7 are preferably fastened to the inner faces of the flat flanges 11a and 11b, that is to say the faces of the flanges that face one another, whereas the ends of the tie rods 9a, 9b, 9c, 9d are preferably fastened to the outer faces of the flat flanges 11a and 11b.

[0063] In one possible embodiment, the ends of the two tie rods which are fastened to one and the same flat fastening flange are identical, and are conventionally formed by a flattened end piece fastened or integrated to or with one end of the longitudinal body of the tie rod (see, for example, the flattened end 20 for the tie rod 9a in FIG. 4) pierced with a circular through-opening to allow the passage of the screw of the bolting system.

[0064] In another embodiment, one end of one of the two tie rods further comprises a play-compensating device, for example an eccentric washer making it possible to vary the fastening center distance between the two ends of this tie rod. In the case of FIG. 3, the end of the tie rod 9b, on the one hand, and of the tie rod 9d, on the other hand, comprises such a play-compensating device 21. In this embodiment, in order to facilitate the mounting operations, the tie rods whose end does not comprise a play-compensating device (namely the first tie rod 9a and the third tie rod 9c of FIG. 3) are preferably mounted first such that their respective end is in contact with the fastening surface formed by the corresponding flat flange. The tie rods whose end comprises a play-compensating device (namely the second tie rod 9b and the fourth tie rod 9d of FIG. 3) are then mounted above such that their respective end is in contact with the end of the tie rod mounted first.

[0065] In all the cases, the use of fastening plates conforming to what has just been described makes it possible to divide by three the number of bolting systems necessary for the mounting of the lattice beam structure, which allows mounting time to be saved and contributes to a reduction in the total weight of the lattice support beam.

[0066] Furthermore, since two tie rods and one crossmember are held at a single point for each flat flange 11a, 11b, the forces of these two tie rods and of this crossmember are transmitted first of all to the screw of the associated bolting system before being transmitted to the fastening plate. Simulations have in particular made it possible to show that, in one and the same loading situation, a fastening plate such as the fastening plate 8c of FIG. 3 receives up to 70% less force than the fastening plate 8c of FIG. 2.

[0067] Moreover, the fact that the direction of the forces of the two tie rods and of one crossmember passes through the center of the corresponding flat flange makes it possible to reduce the risks of pull-out of the fastening plate with respect to the longitudinal member, and of deformation of the flat flanges.

[0068] Since the fastening plate is subjected directly to less force, it is also possible to reduce its size, more precisely the length of its central surface 10 and of the flat flanges 11a, 11b in the longitudinal direction of the longitudinal member 4, by half with respect to the fastening plate 8c of FIG. 2. This results in a reduction by half of the weight of each fastening plate used for the mounting of a lattice support beam, which further contributes to a reduction in the total weight of the lattice support beam.

[0069] The same advantages as those described above are of course obtained in the case where the lattice support beam comprises equilateral triangular assemblies. In this case, all the fastening plates fastened to the three longitudinal members are identical and each comprise two flat flanges forming between them an angle equal to substantially 60°.