LATTICE COVERING STRUCTURE

Abstract: A lattice covering structure consisting of modular inver­ ted pyramidal members (1) having rectangular or square bases (2) as well as of a lower lattice wherein the knot at the apex of the pyramid is made up of plate means (9) on which a hollow tubular (11) member is welded at the upper part, to which tubular member (11) the ends of the diagonal rods (3) are welded laterally, said plate means being provided with a central hole for passing the connection means of the single pyramidal member (1) with the rods (13) of the lower lattice that converge to said knot point and in which the connection members (4) at the upper knots consist of plate means (5) which realize the coupling and welding zones of the base rods (2) of the pyramid and of the diagonal rod (3) which concur to each of said knot points, said plate means (5) being provided with coupling means for realizing their coupling with the adja­ cent connection member and with the supporting means of the supports of the whole covering.

Description: LATTICE COVERING STRUCTURE The present invention relates to a lattice covering structure having improved connections of its structural members. More particularly, this invention relates to a space grating covering structure made up of modular members of a pyramidal shape which can very easily transported and assembled in situ with improved connections of their structural members, said structure being useful for covering large rooms or spaces preferably of a rectangular or a square plan. As is well known, three-dimensional lattices forming the covering are made up of two parallel plane lattices, one in the upper position and the other one below the first, such lattices being connected to each other by means of vertical rods or by rods at various slopes. Said lattices which consist of straight rods concurring at the assembly knots do not have necessarily the same warping or member arrangement. Such structural types represent the building systems of major employment for covering large areas, as they have remarkable properties of rigidity and static efficiency as well as of simplicity of the constructive procedures. Indeed, by employing such systems the external load is spread in all directions along said rods which are stressed mainly by axial stresses, bending moments being almost absent. One of the covering types which are more known at the present time consists of a square base pyramid assembly where in the apices are kept together by a base of orthogonal lattice can next be arranged in a direction parallel to the main sides of the structure or in such a way that angles are formed of various amplitudes between the rods of the upper and the lower lattices and the profile or outline of the structure itself. The most employed systems among all such solutions are those in which the rods of the lower lattice form 45 angles with respect to the rods of the upper lattice. It is well known that the types of lattice covering made up of pyramidal members can be associated through the employment of different connection members of the rods at the knots. Indeed, the choice of the knot affects the very construc tive procedure as well as the final strength of the whole structure. Therefore the rod profile, the realization modes, the assembling operations and the cost of the structure all vary as a function of said knot. One of the most employed systems (the so-called MERO sys tem) makes use of a steel sphere as a knot, said sphere having eighteen faces with eighteen threaded holes in which the rods are screwed that are at various slopes but all converge toward the centre of the sphere. The major drawbacks of such system consist in the need for special devices for the realization of said threaded holes, with consequent very high costs of production, as well as in the intrinsic weakness of the connections and in the possible misalignment of the rods. In a similar way, the OKTAPLATTE system employs two hollow hemispheres made up of steel and welded with the interposition of a circular intermediate reinforcement disk, to which hemisphere the rods are fastened by welding at various slopes. Such a system, though easily used in the case of curved surfaces, has the drawbacks due to the high welding concentration at the knot and to the need for performing the construction operations in the building yard during the in stallation of the structure. Among the lattice systems employing prefabricated pyr amidal modular members,. the PYRAMITEC system has the drawback of not respecting the axial directions of the diagonal rods converging to the lower knot as the ends of the latter must be squashed in order to weld the same to the plate of said knot. A further development of such structural type having pyramidal members is represented by the UNIBAT system which, in order to solve the problem of conserving the axial directions of the diagonal rods converging at the knot, adopts the use of square cross section rods on whose squashed lower end a slot is provided through which the bolt is passed for fastening the same to the base plate of the lower knot. Moreover, the upper coupling mechanisms of the single pyramidal members provided at points corresponding to the base edges of the same, which mechanisms have a bolt for each corner, give rise to the need for a further upper support system of the whole covering. It is clearly evident from the above that it is advantageous to have a lattice covering employing the modular pyramidal system and connection members of the structural members capable of giving the lattice structure a good rigidity as well as a perfect axial alignment of the diagonal rods, so that the structure does not require any welding operations during its installation, the number of hole-bolt connections and the pertinent unelastic creeps being lowered at the same time. Moreover, it is undoubtedly advantageous to have a structure whose upper connection members perform simultaneously the function of connecting the base rods of the pyramid and of supporting the bearing members of the covering. According to the present invention, a space lattice structure is pro posed to that aim, which structure consists of pyramidal mod ules, the structural members that each single module is made up of being assembled before installation owing to the particular kind of realization of the lower and the upper connection members. Indeed, according to the present invention the realization is proposed of an upper connection mechanism to which the rods are welded which form the base as well as the pyramid diagonals, which mechanism is successively in the assem being operations coupled to the corresponding mechanism of the adjacent module and therefore to the supporting member of the whole covering and of a lower connection mechanism thtt is made up of a plate to which a tubular member is weld ed, which member allows the diagonal rods to be connected through welding and, during installation, the connection inside the same by means of bolts of the pyramid to the rods forming the lower lattice. Accordingly, it is a specific object of the present invention to realize a lattice covering structure made up of modular inverted pyramidal members with a rectangular or a square base and of a lower lattice, said structure being characterized in that tht lower knot at the apex of the pyramid consists of plate means on which a hollow tubular member is welded at the upper part, to which member the ends of the diagonal rods are laterally welded, said plate means being provided with a central hole for passing the connection means of the single pyramidal member, with the lattice rods of said lower lattice that converge to said knot, the connection members at the upper knots consisting of plate means having at their front parts a number of projecting members which form the coupling and welding zones of the base rods of the pyramid and of the diagonal concurring to each of said knots, said last mentioned plate means being provided with means for realizing their coupling with the adjacent connection member and with the supporting means of the covering supports. According to a preferred embodiment of the present invention, the rods forming the base of the pyramidal members have a square cross section and the rods forming the diagonal member have a circular cross section. Moreover, in order to obtain a higher rigidity in the case of quite large covering spans, additional rods can also be provided arranged along the diagonals of the pyramid base. Again according to the present invention, said connecting member of the upper knots comprises a vertically arranged plate with two parallel horizontal projecting parts which are provided at the central position on said plate and are spaced by a transversal central baffle or diaphragm, two holes being provided on said plate at its lower part for realizing the connection with the adjacent connection member, two further lateral holes being also provided at the upper part for coupl ing purposes as well as a central hole for passing the support means of the covering support. Further according to the present invention said supporting means of the whole covering support are made up of two C-shaped members which are joined at their upper parts by a plate on which a tubular member is welded which is connected to the whole covering support. More particularly, said support means of the whole covering supports are of variable height that decreases from the central part toward the edges of the structure. Again according to the present invention, the rods of the lower lattice are made up of tubular members which are squashed at the point corresponding to the connection with the apex of the pyramid and with the other rod at right angles concurring into the knot. The present invention will be disclosed in the following for illustrative and not for limitative purposes in the figures of the enclosed drawings wherein: Figure 1 represents an exploded perspective view of a pyramidal modular member forming the lattice structure according to the present invention; Figure 2 represents a plan view of a module of the lattice structure according to the present invention; Figure 3 represents a schematic view of the lattice of the structure according to the present invention; Figure 4 represents an assonometric view of the lattice structure of the present invention; Figure 5 represents an assonometric view of the lattice structure according to the present invention with the support means for the covering member; Figures 6, 7 and 8 show particularly the lower and the upper knots of the modular member; ; Figure 9 represents an exploded perspective view of the member of Figure 1 on which the diagonal rods are provided on the base of the pyramid. As can be observed in Figure 1, the pyramidal module 1 of the lattice structure according to the present invention is made up of four base rods 2 having a square cross section and of four diagonal rods 3 having a circular cross section. The base rods 2 are coupled two by two through welding the same to a connection member 4 at a point corresponding to their joining edge which can be shaped in a suitable way. The upper connection member 4 is made up of a plate 5 (see also Figure 6) which plate on the back side is designed for coupling with the corresponding member 4 and has on its front side two longitudinal crosspieces 6 and 7 which are parallel to each other and a vertical crosspiece 8, all such crosspieces defining the surface on which the single rods 2 are welded whereas the vertical crosspiece 8 inserts between said two rods 2 converging at the knot. The upper end of the corresponding diagonal rod 3 is welded on the lower surface of said crosspiece 7 of each connection member 4. Three and two holes are provided respectively at points corresponding to the upper and the lower edges of the back plate member 5 for connecting the pyramidal members to each other and for fastening the support member (not shown) of the whole covering. The four diagonal rods 3 are converging at the lower part into a knot plate 9 consisting of a flat member 10 and a tubular, square cross section member 11 (see also Figures 7 and 8) on whose side faces the ends of the rods 3 are weld ed at the centre position. For example, said flat member 10 can have a thickness of about & 10 mm while said tubular member 11 can be of sizes between 80 x 80 x 3 mm and 100 x 100 x 3 mm. The knot plate 9 has at the central point corresponding to the tubular member 11 a hole for passing the screw 12 for the connection of the member 1 with rods 13 that form the lower lattice. Such connection is made complete through a nut 14 and two washers 15 and 16. Said circular cross section rods 13 are squashed at the connection point with the single members 1 so that said rods can be coupled easily. Thus, when installing the structure, pyramidal members 1 wi2l be available as already assembled members comprising said four base rods and said diagonal rods 3 already connected by welding to the connection members 4 as well as to the knot plate 9 so that, in the assembling step of the struc ture, the only operations to be performed are the assembling operations of said pyramidal members 1 and the connection of the same with the members of the lower lattice and with the supports of the whole covering. With reference now to Figure 2 it is posslbl to observe a plan view of the covering section wherein the rods 2 of the upper lattice forming the base of te pyramid are arranged so as to form an angle of Li50 with the rods 13 forming the lower lattice, so that the plan projection of the diagonal rods 3 corresponds to the central axis of the rods 13 that converge into the knot plate 9. Figure 3 shows schematically as a plan view a kind of embodiment of the lattice structure of the pre set invention made up of the base rods 2 of the pyramid and of the rods 13 of the lower lattice as well as of the projec ticns of the diagonal rods 3. Figure 4 shows an assonometric view of a part of an as serried lattice structure, said part resting on the bearing member 17 arranged along the perimeter of the zone to be covered. It is possible to remark that the upper coupling members 4 cf each pyramidal member are arranged two by two on the op polite edges along perpendicular ine which are respectively parallel to the rods 13 of the lower lattice. figure 5 shows the lattice structure as illustrated in Figure 4 wherein the supporting membes or king-posts 18 of .l rlins 19 of the covering 20 are fastened to the upper connections 4. Said supporting members 18 are fastened to said member 4 by means of a bolt passing through the central hole of the three holes provided in the upper edge of said plate member 5 of said connection member 4 (see Figures 1 and 4 > . Said supporting members or king-posts 18, consisting of two C-shaped members spaced from each other, are joined at their upper parts through a plate 21 on which a tubular member 22 is arranged. Said two back plates 5, coupled by two adjacent connection members 4, are inserted between said two C-shaped memhers, while one of said purlins 19 is coupled to said tubular member 22. Said king-posts 18 will be of gradually decreasing height from the centre of the structure toward its peripheral part so as to give the covering the desired slope. Figure 9 shows finally the rods 23 arranged on the diagonals of the base of said pyramidal member 1. The employment of said rods 23 allows the commercially available profiles for the upper rods 2 to be employed in the case of large covering spans (for instance, of 50 x 50 m). The present invention has been disclosed for illustrative but not for limitative purposes and it is to be understood that modifications and changes can be introduced by those who are skilled in the art without departing from the scope of the invention for which a priority right is claimed.

Claims: nLA 1. A lattice covering structure made up of modular inver ted pyramidal members which have rectangular or square bases and of a lower lattice, said structure being characterized in that the knot at the apex of the pyramid consists of plate means on ;which a hollow tubular member is welded at the upper part, to which tubular member the ends of the diagonal rods are laterally welded, said plate means being provided with a central hole for passing the connection means of the single pyramidal member with the rods of the lower lattice which con verge into said knot, said structure being in addition characterized in that the connection members at the upper knots are made up of plate means having projecting members at their front parts which projections realize the coupling and welding zones of the base rods of the pyramid and of the diagonal rod concurring to each of said knots, said last mention ed plate means being provided of coupling means for coupling the same with the adjacent connection member as well as with the supporting means of the covering suppcrts. 2. A lattice covering structure according to claim 1, characterized in that the rods forming the base of the pyramidal members are of a square cross section. 3. A lattice covering structure according to claims 1 and 2, said structure being characterized in '2r 8t rods forming the diagonal members are of circular cross section. A A lattice covering structure according to claim 1, characterized in that said connection member of the upper knots comprises a vertically arranged plate having two parallel horizontal projecting parts provided at the centre part on e e and spaced from each other by a transversal cen- tral diaphragm or baffle, two holes being provided on said plate at its lower part for coupling with the adjacent connection member, two additional side holes being also provided at the upper part for coupling purposes as well as a cen tral hole for passingthe supporting means of the whole cover ing support. 5. A lattice covering structure according to claim 1, characterized in that said supporting means of the whole covering support are made up of two C-shaped members which are joined at the upper part by a plate on which a tubular member is welded which couples with the support of the whole covering. 6. A lattice covering structure according to claims 1 and 5, characterized in that said supporting means of the covering supports are of variable heights decreasing from the centre toward the edges of said structure. 7. A lattice covering structure according to claim 1, characterized in that said rods of the lower lattice are made up of tubular members which are squashed at the point of connection with the apex of the pyramid and with the other perpendicular rod concurring at the knot. 8. A lattice covering structure according to claim 1, characterized in that rods are provided on the diagonals of the base of said pyramid.

Inventors: GANDOLFI, ALFREDO
Applicants: GANDOLFI, ALFREDO
Application year: 1986
Main classification: E04B1
IPC codes: E04B1