MODULAR JOINT FOR INDUSTRIAL METAL STRUCTURES

Abstract: A modular joint (1) for industrial metal structures, intended for connecting substantially vertical uprights (M) and substantially horizontal beams (T), in which each upright consists of a hollow section with flat side walls and with an open top end, and each beam comprises a pair of mutually facing plates with substantially flat cores (A). The joint (1) comprises a locking element (2) which can be slidably inserted into the open end of a corresponding upright (M) and is provided with connecting members for releasable connection to at least one horizontal beam (T) along each of the side walls of the upright. The locking element (2) comprises a tubular body with a square or polygonal shaped cross-section, substantially matching that of the internal cavity of the upright, having at one longitudinal end a flat closing flange (4). The tubular body is formed by substantially flat side walls (3) having an average thickness greater than that of the walls of the upright. The connecting members comprise a plurality of threaded holes (7) formed in all the flat side walls of the locking element (2) and adjustable with corresponding through-holes (8) formed in coinciding positions in all external faces of each upright in the vicinity of the open top end.

Description: MODULAR JOINT FOR INDUSTRIAL METAL STRUCTURES Technical field The present invention relates to a modular joint for light metal structures such as raised platforms, large-size shelving and storage frames. Background art Structures of the abovementioned type which are essentially formed by vertical load-bearing uprights or columns which are rigidly connected to substantially horizontal beams so as to form a reticular support structure for walkways, roofs, raised surfaces or the like are known. The connections between the columns and the beams, as well as between the latter, are generally performed by means of welded joints or, more commonly, are bolted so as to allow the assembly thereof in situ without the need for specialised labour. Examples of these bolted or welded joints are illustrated in EP-A-1 7574, FR-A-2034093, US-A-339991 4, US-A-49001 08, FR-A-256491 0 and GB-A-2049863. Italian patent IT-A-1 267679 discloses a raised-platform structure comprising vertical load-bearing columns which support a flat frame formed by main and secondary beams on which a walkway rests. In order to perform the connection between the columns and the beams, the top of each column has, welded to it, a flange with, fixed to it, a joint or "capital" formed by a first horizontal plate which is provided with holes for the bolts for connection to the flange of the column and to which a pair of mutually perpendicular vertical plates is welded. The vertical plates have, welded to them, a second horizontal plate along the edges of which the ends of the horizontal beams are positioned. This constructional form of the capital joint is suitable for the connection of corner structures, with beams positioned on two adjacent sides of the joint. In order to perform the connection of the columns with horizontal beams also on the other two sides of the columns, constructional forms of the joint with the addition of one or two vertical plates coplanar with the first two are envisaged. In order to mutually connect the main and secondary beams, connecting devices in the form of L-shaped rectangular plates of a type known per se are envisaged. The beams are formed by pairs of sections with a sigma-shaped cross-section, which are mutually facing and have flat surface zones provided with holes for receiving bolts for connection to the vertical plates - also perfectly flat - of the capital joints. Even though this type of joint solves in a satisfactory manner the problem of providing a connection between the columns and the beams, it is not devoid of some recognised drawbacks including in particular the high cost and lack of flexibility during assembly and modification of the existing metal structures. In fact, according to the number of horizontal beams to be connected to the columns it is necessary to use a different type of capital joint with two, three or four vertical plates. Moreover, in the case where it is required to modify an existing structure, adding one or more horizontal beams to corner structures with only two horizontal beams, it is necessary to disassemble the capital joint with a pair of vertical plates in order to replace it with another joint which has three or four vertical plates, with consequent greater labour costs and availability of warehouse parts. A further drawback consists in that the connection between the beams and the plates of the capital joints is substantially of the "hinge" type, owing to the fact that the surfaces for connection of the beams and the vertical plates of the joints are substantially flat and mutually joined together solely by means of friction and therefore do not allow interlocking moments to be transmitted. Thus, the "hinge type" connection of the joints to the horizontal beams produces on these latter high sag (deflection) forces which increase further and may be excessive when the horizontal beams are loaded with constructional elements such as panels for the walkways or brackets. Moreover, in order to provide the raised platform with balustrades, it is necessary to fix to the peripheral beam uprights or vertical sections to which horizontal tubes which form the handrails of the balustrade are then fastened. However, in order to comply with the existing safety regulations, the beams must be reinforced at the point of connection with the uprights, with consequent greater costs and complexity of the structure. Finally, the structure of this known joint, like that of other similar joints, has a large number of projections and is therefore aesthetically unattractive. Disclosure of the invention A main object of the present invention is to eliminate the drawbacks mentioned above, providing a modular joint for the connection of vertical uprights and horizontal beams having characteristics of high flexibility and reliability at a low cost. A particular object is that of providing a modular joint which can be used for all reticular structures with two or more horizontal beams connected to each side of the upright without modifications or additions. Another particular object is that of providing a modular joint with a simplified and robust structure, able to guarantee a considerable dimensional stability of the raised floor structure or the like, while keeping the sag (deflection) of the beams within low values. A further object is that of providing a modular joint which allows a balustrade structure to be fitted at an extremely low cost. Yet another object is that of designing a modular joint which has a compact configuration without projections so as to be aesthetically pleasing. These objects, together with others which will appear more clearly below, are achieved in accordance with Claim 1 , by a modular joint for industrial metal structures, suitable for the connection of substantially vertical uprights and substantially horizontal beams, in which each upright comprises a hollow section with flat side walls and with an open top end, and each beam comprises a pair of mutually facing sections with substantially flat central cores, characterized in that it comprises a locking element which can be slidably inserted into the open end of a corresponding upright and is provided with connecting members for releasable connection to at least one horizontal beam along each of the side walls of the upright. As a result of this arrangement, the joint has an extremely simple and flexible structure, helping to increase the reliability of the structure at a relatively low cost. Moreover, the modular joint thus obtained may be used for all reticular structures with two or more horizontal beams connected to each side of the upright without modifications or additions. Finally, the simplified and robust configuration of the joint ensures a notable dimensional stability of the structure, keeping the sag (deflection) of the beams within low values. Brief description of the drawings Further features and advantages of the invention will be more clearly understood with reference to the detailed description of a preferred, but not exclusive embodiment of the joint and the metal structure according to the invention, illustrated by way of a non-limiting example with the aid of the accompanying plates of drawings, in which: Fig. 1 shows a general perspective view of a metal structure which uses a series of modular joints according to the invention; Fig. 2 shows a perspective view of a detail of a modular joint according to Fig. 1 on a larger scale; Fig. 3 shows a perspective view of the detail according to Fig. 2 during insertion into an upright of the structure; Fig. 4 shows a perspective view of the detail according to Fig. 2 inserted into the upright; Fig. 5 shows a perspective view of another detail of the joint according to Fig. 1 on a larger scale; Fig. 6 shows a perspective view of the detail according to Fig. 5 during joining to an upright of the structure; Fig. 7 shows a perspective view of the detail according to Fig. 5 joined to the upright; Fig. 8 shows a perspective view of the detail according to Fig. 5 during joining to a beam of the structure; Fig. 9 shows a perspective view of the detail according to Fig. 5 joined to a beam and to an upright; Fig. 1 0 shows a cross-sectional view of the joint according to the invention sectioned along a horizontal plane; Fig. 1 1 shows a cross-sectional view of the joint according to Fig. 1 0 sectioned along the vertical plane indicated by the line XI-XI; Fig. 1 2 shows a perspective view of a portion of the structure according to Fig. 1 to which a section of a balustrade has been joined; Fig. 1 3 shows an exploded perspective view of the balustrade structure according to Fig. 1 2. Detailed description of the preferred embodiment(s) With reference to Fig. 1 , a metal reticular structure, generally indicated S, of the type used for the construction of raised platforms or raised storage frames is illustrated. The structure S essentially consists of a series of uprights M which are substantially vertical and which support a flat frame formed by a plurality of substantially horizontal beams T arranged along the periphery and inside the frame itself. In a per se known manner, each upright M has a main body consisting of a hollow section portion, with a square or in any case polygonal cross-section and with flat side walls, provided at the bottom end thereof with a flange F for fixing to the ground and an open top end. Each beam T, which is also of a per se known type, consists of a pair of pressed or profiled plates P with a substantially C-shaped cross-section, as can be seen more clearly in Figures 8 and 9, which face each other and have vertical cores A which are substantially parallel and slightly reciprocally spaced in the transverse direction. The cores A have, formed along them, a first series of larger size holes for receiving cables, pipes and other devices, and a second series of smaller-diameter holes for connection to other beams and to the uprights M. The uprights M are connected to the beams T by means of a series of joints which are each denoted by the reference numeral 1 . According to the invention, each joint 1 comprises a locking element 2 which can be slidably inserted into the open end of an upright M and is provided with connecting members for releasable connection to at least one beam T along each of the side walls of the upright. In particular, the locking element 2 consists of a tubular body with a substantially square or polygonal shaped cross-section matching that of the , internal cavity of the upright M. The tubular body of the locking element 2 is obtained by the union of vertical side walls 3 welded along the edges thereof and having preferably an average thickness greater than that of the side walls of the uprights M. A longitudinal end of the tubular body has, fixed thereto, a flat closing flange 4 which has a shape, in plan view, the same as the cross-section of the upright, so as to have a peripheral edge projecting with respect to that of the tubular body. Along this projecting peripheral edge, the flange 4 may have threaded circular holes 5 and oblong holes 6. Thus, each locking element 2 may be inserted into the internal cavity of a respective upright M, inserting into the oblong holes 6 special pins of an extractor, not shown in the drawings. Moreover, its projecting peripheral edge may come into abutment against the free top edge of the upright prior to connection with the beams T. In an advantageous manner, all the side walls 3 of the tubular body have a plurality of threaded holes 7 corresponding to smooth through-holes 8 formed in registered positions over all the external surfaces of the upright M in the vicinity of its open top end. After insertion of the element 2 into the open end of the upright M, the through-holes 8 will be aligned with the threaded holes 7. The connecting members of the joint 1 also comprise, along each side of the upright, an interface surface, generally indicated by the reference numeral 9, which is essentially T-shaped and intended to be housed between the cores A of each beam T. Each interface element 9 is essentially formed by a substantially vertical flat flange 1 0 to which at least one and preferably two specular plates 1 1 - which are also substantially vertical and perpendicular to the flange 1 0 and separated by spacers 1 2 - is/are connected. The flange 1 0 has a plurality of through-holes 1 3 in registration with the holes 8 of the upright for insertion of bolts, not shown in the drawings, intended to be screwed into the said threaded holes 7 formed in the locking element 2. Each vertical plate 1 1 has a series of holes 1 4 for receiving connecting screws - not shown in the drawings - inserted into corresponding holes 1 5 formed in the cores A of the beams T. Preferably, each plate 1 1 has formed thereon at least one horizontal linear projection 1 6 which is intended to engage into a corresponding groove 1 7 of matching shape formed in each core A of a beam T. Thus, the connection between each upright and a beam will not be of the "hinge" type, but will tend to be of the "interlocking" type so as to reduce considerably the sag (deflection) of the said beam. In order to fix a balustrade structure 1 8 to the load-bearing frame of the beams T, it is possible to secure vertical uprights 1 9 to the closing flange 4 owing to the presence therein of threaded holes 5 on the flange 4 of the locking element 2. The horizontal rail sections 20 and the retaining panels 21 may be fixed onto the uprights 1 9, thus ensuring the necessary safety and stability. Thus, it is possible to dispense with members for reinforcing the beams T at the joints 1 and reduce the number of parts and connecting elements, while increasing the robustness of the balustrade. From the foregoing description it is obvious that the joint according to the invention achieves the predefined objects and attention is drawn in particular to its flexibility and modular nature, as well as its robustness and constructional simplicity. Moreover, the joint according to the invention allows to modify and expand easily the raised platform structures without removing and replacing the existing joints with others of a different type. Even though the joint according to the invention has been described with particular reference to the accompanying drawings, it may be subject to numerous modifications and changes which fall within the inventive idea expressed in the accompanying claims and which are understood as being similarly protected. Moreover, all the details may be replaced by technically equivalent elements, and the materials may vary according to the requirements. The instant application is based upon Italian patent application VI2000A000006, filed on 10 January 2000, the disclosure of which is hereby expressly incorporated by reference thereto, and the priority of which is hereby claimed.

Claims: CLAIMS 1 . A modular joint (1 ) for industrial metal structures, intended for connecting substantially vertical uprights (M) and substantially horizontal beams (T), in which each upright consists of a hollow section with flat side walls and with an open top end, and each beam comprises a pair of mutually facing plates with substantially flat cores (A), characterized in that it comprises a locking element (2) which can be slidably inserted into the open end of a corresponding upright (M) and is provided with connecting members for releasable connection to at least one horizontal beam (T) along each of the side walls of the upright. 2. Modular joint according to Claim 1 , characterized in that said locking element (2) comprises a tubular body with a square or polygonal shaped cross-section substantially matching that of the internal cavity of the upright and having a flat closing flange (4) at a longitudinal end thereof. 3. Modular joint according to Claim 2, characterized in that said tubular body is formed by substantially flat side walls (3) with an average thickness greater than that of the walls of the upright. 4. Modular joint according to Claim 1 , characterized in that said connecting members comprise a plurality of threaded holes (7) which are formed in all the flat side walls of said locking element (2) and which can be registered with corresponding through-holes (8) formed in coinciding positions over all the external surfaces of each upright in the vicinity of the open top end thereof. 5. Modular joint according to Claim 4, characterized in that said connecting members comprise on each side of said upright an interface element (9) which is essentially formed by a flat flange (1 0) which is substantially vertical and to which there is connected at least one plate (1 1 ) which is also substantially vertical and perpendicular to said flange (1 0). 6. Modular joint according to Claim 5, characterized in that said flange (1 0) has a plurality of through-holes (1 3) coinciding with the through- holes (8) of said upright (M) for the insertion of bolts intended to be screwed into said threaded holes (7) formed in the locking element (2). 7. Modular joint according to Claim 5, characterized in that said at least one vertical plate (1 1 ) has holes ( 1 4) for receiving connecting screws inserted into corresponding holes formed in the cores (A) of said beams (T). 8. Modular joint according to Claim 5, characterized in that said interface element (9) comprises a pair of mutually parallel and slightly spaced vertical plates ( 1 1 ) joined to said vertical connecting flange ( 1 0) and adopted to be housed between the cores (A) of each beam. 9. Modular joint according to Claim 8, characterized in that said at least one plate (1 1 ) comprises at least one horizontal linear projection ( 1 6) intended to engage in a corresponding groove (1 7) with a substantially matching shape formed in each core (A) of a beam for transmitting thereto an interlocking moment. 1 0. Modular joint according to Claim 2, characterized in that the closing flange (4) of said locking element (2) is provided with connecting holes (5) for a vertical upright (1 9) of a balustrade (20). 1 1 . Metal structure for industrial raised platforms and storage frames, comprising a plurality of substantially vertical uprights (M) which support a substantially flat frame formed by a plurality of substantially horizontal beams (T), in which each upright comprises a hollow section with flat side walls and each beam comprises a pair of mutually facing sections with substantially flat central cores (A), characterized in that each upright (M) has an open top end and is connected to one or more beams by means of a modular joint (1 ) according to one or more of the preceding claims.

Inventors: GASTALDELLO GIULIANO, GASTALDELLO, GIULIANO
Applicants: GASTALDELLO GIULIANO, TORRI SPA, GASTALDELLO, GIULIANO, TORRI S.P.A.
Application year: 2001
Main classification: E04B1
IPC codes: E04B1