STRUCTURE MADE OF WEB MEMBERS FOR TRUSSES

Abstract: A structure (12) made of web members for trusses (11) in which the web members (20) are produced in a single piece and firmly attached to each other at their extremities, where the firmly attached extremities of each pair of consecutive and adjacent web members (20) are converging at peak points (21, 21') of the structure (12) and the opposite extremities of the pairs of the consecutive and adjacent web members (20) are distanced from each other to form a continous structure suitable for being associated with the braces (13) of the trusses (11).

Description: "Structure Made of Web Members for Trusses" This invention refers to a structure made of web members for trusses. It is known that trusses are constituted by braces interconnected by web members. These web members may be constituted of cross ties and/or cross stiffening brackets, depending on the stresses the beam has to bear. The cross ties are usually employed where structures must be built to withstand considerable stresses, in particular of a flexing type, and where structures of considerable size must be erected, for instance for large portals or great widths. The cross ties are connected to the braces by interposing cleats which support the cross ties and strengthen the joint. The connection may be made in various ways, by using elements such as nails, bolts, welded joints and the like. The cross ties of a known type normally imply that in order to make the connection and consequently produce the truss, a rather high number of connecting elements must be employed. This obviously means that the resulting structures are extremely heavy, complex and actually expensive . Moreover, the erecting phase turns out to be long and complex, as every single cross tie must be associated with the braces, and all the connecting elements must be applied. The mentioned drawbacks are accompanied by the fact that it is very often impossible to physically observe the convergence of the axes of gravity of the cross ties with those of the braces. The purpose of this invention is to eliminate the mentioned technical drawbacks, by producing a structure made of web members for trusses capable of allowing the completion cf mutual connections of a simple structural type between the braces. Another purpose of the invention is to produce a structure made cf web members capable of being connected to the braces by a few quick and simple steps. A further purpose of the invention is to build a structure made cf web members capable of being produced with a very limited amount of scraps, and consequently in an essentially inexpensive manner. Not the least purpose of the invention is to create a structure made of web members capable of producing trusses cf a safe and reliable type. These and ether purposes according to this invention are attained by a structure made of web members for trusses as outlined in claim 1. In an advantageous manner, the structure made of web members according to the invention allows achieving trusses of a light weight and therefore also of a type capable of being built from expensive materials, such as for example stainless steels, special high or extremely high strength steels and aluminum. The assembling of the trusses which mount the web members according to the invention also demands only a limited number of connecting elements such as nails, bolts or the like. This allows producing structures comprising trusses in substantially less time, at lower costs and with smaller quantities of materials with respect to those used for conventional trusses. Further characteristics and advantages of a structure made of web members according to this invention will become more clearly evident from the following description, offered for exemplifying and non-limiting purposes, with reference to the simplified attached drawings, in which: Figure 1 is a front view of a portion of a steel sheet from which various structures made of web members are to be cut according to the invention, where a dashed and dotted line indicates the sheet cutting lines, and a dashed line the undercuts and notches to be applied on the same; Figure 2 is a front view of a portion of a single structure made of web members according to the invention, in a partial stage of production; Figure 3 is a front view of the portion of the structure made of web members shown in Figure 2, in a completely finished form, Figure 4A is a lateral cross section of a portion of a truss mounting web members according to the invention, made along the line IV-IV of Figure 5; Figure 4B is a lateral cross section of a portion of a truss mounting various embodiments of the structure made of web members according to the invention; Figure 5 is a frontal cross section of a truss mounting web members according to the invention, made along the line V-V of Figure 4A; Figure 6 is a front view of a portion of a steel sheet from which various structures made of web members according to the invention are to be cut in a second embodiment, where a dashed and dotted line indicates the cutting lines from the steel sheet, and the dashed line the undercuts and notches to be applied on the same; Figure 1 is a front view of a portion of a single structure made of web members obtained from the steel sheet shown in Figure 6, in a partial stage of production; Figure 8 is a front view of the portion of the structure made of web members shown in Figure 7, in a completely finished form; Figure 9 is a lateral cross section of a portion of a truss mounting the structures made of web members shown m Figure δ, made along the line IX-IX of Figure 10; Figure 10 is a front section of a truss mounting structures according to the invention, made along the line X-X of Figure 9. The particular reference to the Figures from 1 to 5 shows a structure made of web members, indicated m its overall form by the number 12, that is part of a truss 11. The truss 11 comprises four oraceε 13 arranged along its edges. The braces 13 are for instance formed by a central portion 14 profiled m the snape cf an "L", with siαeε 15 of an equal size. An appendix 16 projects from each of the sides 15, which is aisc profiled m the shape of an "L" and has siαes 17 of essentially tne same size ana equal to half tne size of tne sides 15 of the central portion 14, so that the respective peaks 18 of the appendices 16 are facing each other. In a first embodiment of the truss 11, the braces 13 are connected with each other oy four structures 12 made of web members according to tne invention. The structures 12 connected to a single brace 13 are offset between each other, so as to allow them to be connected without interfering with each other m a crossing area 19. The structure 12 made of web members is composed of a continuous series of cross ties 20 produced from a single piece with a "U" shaped cress section. Two consecutive and adjacent cross ties 20 (Figure 4A) have their first extremities firmly attached to each other and converging in peak areas 21 of the structure 12, and their opposite extremities separated from each other and firmly attached to other consecutive cross ties 20. These structures 12 are connected to the braces 13, in their respective peak areas 21, by a pair of connecting elements 34; of course the cross ties 20 at the extremities are not firmly attached tc any other cross ties 20. The peak areas 21 are also firmly attached tc some cleats 22, which are made in a single piece with the extremities of the cross ties 20, in the form of appendices bent in the shape cf an "L" and suitable for being associated with the internal surfaces cf the sides 15 of the portion 14 of the braces 13. A first flap 35' of the appendices is profiled as a rectangle, while a second bent flap 35' ' is profiled as a triangle in order to optimize the use of the material. The two sides of the "U" of the cross ties 20 form wings 23 having oblique extremities 24 for technological reasons, cr some material would have to be added; this advantageously allows connecting the structure 12 to the braces 13, and keeping the wings 23 from becoming a hindrance. The connection of the structure made of web members 12 to the braces 13 is made by associating the bent flap 35' ' of the cleats 22 with the internal side 15 of the braces 13, and at the same time associating the cross ties 20 with one side 17 of the appendix 16 having the same lying. In a preferred embodiment shown in Figure 4B, the connection between the braces 13 and the cross ties 20 is made in such a way that the axes of gravity 25 of the cross ties 20 come to cross the axis of gravity 26 of the brace 13. In this manner the axes of gravity 25, marked by a dashed and dotted line, converge at the center of gravity 36 of the braces 13. The connection in this embodiment is made by utilizing three connecting elements 34. The connection of the cross ties 20 to the braces 13 is made by using connecting elements 34 such as nails, bolts, welds or other known devices. The process for producing the structure 12 of web members for trusses 11 according to the invention is as follows. The work starts from a steel sheet 27, for instance of a size of 2 x 6 meters (2000 x 6000 mm) . In a first processing phase (Figure 1) , where some cross ties 20 have a "U"- shaped cross section and a sloping angle α toward the braces 13 of for example 45° when mounted, the steel sheet 27 is cut into saw-tooth profiled sections, so as to produce some consecutive and adjacent cross ties 20 which are symmetrical in pairs with respect to the axes of symmetry 33 set at an orthogonal angle to the axis of gravity 26 of the braces 13 when the structure 12 is mounted on the braces 13 in order to produce the truss 11. A distance Li between the two successive peak areas 21, measured along a direction parallel to the braces 13 when the beam 11 is mounted, is a function of the sloping angle α of the cross ties 20 on the braces 13. In order to allow the steel sheet 27 to cover a whole number of cross ties 20, the distance Li must be a whole multiple of the width of the steel sheet 27. A distance Hi between the two successive peak areas 21, measured along a direction set at a right angle to the braces 13 when the beam 11 is mounted, is a function of the height of the desired truss 11. Finally, a distance L 2 between two successive cuts is a function of the execution of the λλ U" shaped cross section. The cut of the steel sheet 27 can be made by a steel cutter, a plasma or laser cutter, or any other known system. During the cutting and rounding off, some undercut areas 28 are removed and some notches 28' are applied, as needed for the subsequent bending of the cross ties 20. In a second phase (Figure 2), the steel sheet 27 is cut up into elements 29 and the processing scrap due to the undercut areas 28 is removed. After cutting and separating the steel sheet 27 into several elements 29, some eventual welding is done at the extremity 30, in order to produce structures 12 whose dimensions are larger than those of the steel sheet 27. This weld 30 is preferably applied in a butt fashion along the extremity 31 of the cross ties 20. In a third phase the elements 29 are bent along the dashed lines 32 shown in Figure 2, so as to produce the λλ U"-shaped profile of the cross ties 20 shown in Figure 3. Appropriate mechanical dies or cutters, press-cutters etc. are used for this purpose. The structures made of web members 12 are finally connected to the braces 13, in order to produce the truss 11 shown in the Figures 4A and 5. In a second embodiment shown in the Figures from 6 to 10, the braces 13 of the truss 11 are connected by four structures 12 made of web members according to the invention, which are in this case not offset between each other but converge in the same area of the braces 13, and therefore connect to each other in the crossing areas 19. The structures 12 made of web members are similar to those of the previous embodiment. As shown in Figure 6, the triangular portions shown by the reference number 28' ' ' (which constitute the flaps 35'' of the structures 12) are removed while the undercut areas 28 are particularly extended, so as to avoid any interference when the structures 12 are mounted on the truss 11. It should be added that the undercut areas thus obtained as shown in Figure 6 may be produced by limiting the number of the individual cuts to be made. After cutting the steel sheet 27 as shown, the elements 29 shown in Figure 7 are obtained. For the reasons already mentioned, the elements 29 present highly extended undercut areas and different peaks 21 and 21' at their ideal opposite sides. The peaks 21 are in fact identical to those already described, while the peaks 21' differ from the former due to their lack of the triangular flap 35' ' (constituted by the triangular portion 28' ' ' of the steel sheet 27 in Figure 6) , which has been removed here, and due to the fact that the flaps 35' are bent at right angles with respect to the cross ties 20 along the dashed lines 32. The structures made of web members 12 formed in this manner are used to produce trusses 11 in a second embodiment. The trusses 11 in this second embodiment also comprise four braces 13, which are mutually joined by the structures made of web members 12 according to the invention. In particular, as shown in the Figures 9 and 10, every structure made of web members 12 has a peak of its own 21 opposite a peak 21' of an adjacent structure made of web members 12, and in the same manner a peak of its own 21' is set opposite a peak 21 of an adjacent structure made of web members 12. A first structure made of web members 12 has every peak 21, equal to that of the structure made of web members 12 according to the first embodiment, attached to one of the braces 13 as described above, meaning with one bent flap 35' ' associated with the side 15, and simultaneously with the cross ties 20 associated with one side 17 of the appendix 16 having the same lying. The cross ties of a second structure 12 converging on the same brace 13, on the other hand, present a bent flap 35' connected to a portion of the first structure 12 comprised between two adjacent cross ties 12 and the flap 35' . The resulting truss is shown in a sectionalized form in the Figure 10. In this second embodiment the beam mounting the structures made of web members 12 according to this invention is particularly strong and susceptible to suffer very little distortion. In another embodiment, the structures made of web members 12 can be produced as outlined in the second example, but without removing the triangular portions 28' ' ' of the steel sheet. In this case, while the peaks 21 of the first structure 12 are connected to the braces 13 as already described, the peaks 21' of a second structure made of web members 12 converging on the same brace 13 are connected to the same as indicated in the second embodiment, with the flaps 35' and 35' ' constituting a single flat element bent with respect to the cross ties 20. In a different embodiment of the truss 11, the braces 13 are joined in two pairs by the structures made of web members 12 according to the invention, and these pairs of braces 13 are in turn joined by cross stiffening brackets other known devices. This allows building trusses 11 of even a highly complex structure, optimized to withstand a variety of stresses at various levels. The structure made of web members according to the invention may also comprise various combinations of cross ties and/or cross stiffening brackets, depending on the requirements and stresses the truss must bear. It was in practice observed that the structure made of web members proves to be particularly advantageous for the savings it affords in connecting elements. This of course translates to savings in terms of weight of the trusses, and thus essentially to economical savings. Moreover, the installation of the trusses utilizing structures made of web members according to the invention turns out to be considerably simpler, quicker, and more automatic. The structure made of web members for trusses conceived in this manner lends itself to numerous modifications and variants, all falling within the scope of the invention; moreover, all the details may be substituted by others technically equivalent. In practice the materials used and their dimensions may be of any type, depending on the technical requirements.

Claims: CLAIMS 1. A structure (12) made of web members for trusses (11) characterized in that said web members (20) are produced in a single piece and firmly attached to each other at their extremities, where said firmly attached extremities of each pair of consecutive and adjacent web members (20) converge in a peak area (21, 21') of said structure (12), and the opposite extremities of said pairs of consecutive and adjacent web members are distanced from each other, so as to form a continuous structure suitable for being associated with some braces (13) of said truss (11) . 2. A structure (12) according to claim 1, characterized in that said web members (20) are constituted by cross ties. 3. A structure (12) according to claim 2, characterized in that said peak areas (21) are firmly attached to cleats (22) produced in a single piece with said extremities of said cross ties (20) , so as to facilitate connecting said structure (12) to said braces (13) . 4. A structure (12) according to claim 3, characterized in that said cleats (22) are constituted by appendices bent to an "L" shape and suitable for being associated to said braces (13) of said trusses (11). 5. A structure (12) according to claim 2, characterized in that said consecutive and adjacent cross ties (20) are symmetrical, in pairs, with respect to the axes of symmetry (33) set at right angles to an axis of gravity (26) of said braces (13), when said structure (12) is mounted on said braces (13) in order to produce said truss (11) 6. A structure (12) according to claim 2, characterized in that said braces (13) are formed by a central "L"- shaped portion (14) having sides (15) of a essentially identical size, projecting appendices (16) also having essentially identical sides (17), an "L" shape and essentially half the size of said sides (15) of said central shaped section (14), where the peaks (18) of said appendices (16) having an "L" shape are facing each other. 7. A structure (12) according to claim 6, characterized in that said web cross ties (20) have axes of gravity (25) essentially crossing each other at the center of gravity (26) of said braces (13) . 8. A structure (12) according to claim 7, characterized in that said braces (13) are present in a number of four. 9. A structure (12) according to claim 8, characterized in that it mutually connects at least two pairs of said braces (13) of said truss (11) . 10. A structure (12) according to claim 1, characterized in that it is firmly attached to at least another of said structures (12), in order to produce composite structures suitable for connecting some braces (13) to each other, whose size exceeds that of a single structure (12) . 11. A structure (12) according to claim 1, characterized in that it lacks any triangular portions (28''') that constitute its bent flaps (35''). 12. A structure (12) according to claim 4, characterized in that some second peaks (21') set on an ideal side of said structure (12) differ from said peaks (21) set at an opposite ideal side of the same, because they lack a triangular flap (35'') of said appendix which constitutes said cleat (22) . 13. A truss (11), characterized in that it comprises four braces (13) , where said braces (13) are connected to each other, at least in pairs, to structures made of web members (12) . 14. A truss (11) according to claim 13, characterized in that said structures (12) made of web members converge to a same area of said braces (13) and are therefore connected to each other in crossing areas (19) . 15. A truss (11) according to claim 14, characterized in that a first structure made of web members (12) has peaks (21) firmly attached to one of said braces (13) where its first bent flaps (35' ' ) are associated with the sides (15) of a portion (14) of said braces (13) and its cross ties (20) are simultaneously associated with the sides (17) of some appendices (16) of said braces (13), and where moreover the cross ties (20) of a second structure (12) converge on the same brace (13) while presenting second bent flaps (35' ) connected to a portion of said first structure (12) comprised between two adjacent cross ties (20) and said second flaps (35').

Inventors: PANTALONE ANTONIO, PANTALONE, ANTONIO
Applicants: PANTALONE ANTONIO, SISTEM ENGINEERING S R L, PANTALONE, ANTONIO, SISTEM ENGINEERING S.R.L.
Application year: 1999
Main classification: E04C3
IPC codes: E04C3, E04H12