LOAD-BEARING STRUCTURE FOR RAISED FLOORS

Abstract: The structure is composed of a plurality of feet (13), each consisting of a section of square tubing which has at the base height adjustment means (16, 17) connected to a ground rest plate (21). Each foot bears on its top four crosspieces (1) obtained by pressing from a sheet metal; the head (4) of the crosspieces is shaped to cover an area of one fourth of the section of the foot tubing. The head edges (4) are turned over to form hooking means (5, 7) for connection to the foot, while screw means (23) are provided for achieving engagement among the crosspieces converging on a same foot and the foot itself. Each crosspiece is again covered by a U-like moulding (11) of plastics which forms the rest plane for modular panels.

Description: This invention relates to a load-bearing structure for raised floors. Raised floors are usually obtained by arranging modular panels over a plurality of feet supporting them at the corners, said feet being preferably connected to a plurality of crosspieces, forming a grid. Usually the upper portion of the foot is configured to support and center the panels which converge over it and is made either by casting or pressing from sheet metal. In either case making is considerably expensive. The crosspieces which form the grid must then provide means of hooking on the foot which must be particularly practical for installation. From GB-A-755 735, described in the preamble of claim 1, is known a load-bearing structure of the foregoing type wherein the feet are tubing open at the upper end to form sockets for receiving spigots provided at the heads of metal beams of I-section. The spigots are separate moulded pieces which are welded to the ends of the beams and are expensive to manufacture and to assemble. It is the aim of this invention to provide a load-bearing structure for raised floors which is free of the drawbacks affecting presently utilised structures. In particular an object of the invention is to provide a structure composed of few basic parts which should be simple and inexpensive. Another object is to provide a structure which is easily assembled without requiring particular equipment. The above aim and objects are achieved by a load-bearing structure for raised floors as defined in the appended claim 1. The features and advantages of the invention will be more apparent from the detailed description of a preferred embodiment given by way of illustration and not of limitation and shown in the accompanying drawings,where: Figure 1 shows a perspective broken view of a crosspiece which comprises the structure for pointing out the form of crosspiece heads; Figure 2 shows a side view of a head of that same crosspiece; Figure 3 shows a part-sectional side view of the foot and two crosspieces mounted to the top of the foot itself; and Figure 4 shows a perpsective view from above of the foot and the crosspieces connected thereto. With reference to the drawings, Figure 1 shows a crosspiece generally indicated at 1 and obtained by bending a sheet metal into a "U" so as to obtain a flat upper face 2 which is continued by two vertical sides indicated at 3. At each of the two crosspiece heads, of which one only is shown in Figure 1 as the crosspiece 1 has been only partially illustrated, the upper face 2 is extended, with respect to the vertical sides 3, to form a triangular zone 4 connected to two bent over, arrow-like arranged lugs 5 spaced apart with respect to the forward edges 6 of the vertical sides 3 by a space 7 of equal amplitude to the thickness of the sheet which forms the square tubing of the foot which will be illustrated herein below. Said vertical sides 3 also have forwardly and in the lowermost part of the head two wings 8 bent over inwards of 90° to be coplanar with said forward edges 6 of the vertical sides 3. The upper front corner of the bent over lugs 5 and the tip of the triangular zone 4 are relieved to create a recessed seat indicated at 9. On each of said vertical sides 3, in the proximity of the forward edges 6 there is provided a through hole 10. Every crosspiece 1 carries a V-shaped moulding 11 of plastics conformed inwardly to encircle the whole flat upper face 2 and partway the vertical sides 3 and cut forwardly to present a triangular zone 12 covering said zone 4 of the crosspiece 1 and with conformation equal to a fourth of a square. The foot 13 which completes the structure is made of a section of square metal tubing comprising walls 22 having a width equal to the width of the crosspiece 1 (Figures 3 and 4). In the lower zone the foot 13 has four pinchings 14 made substantially at the center of each wall 22 of the square tubing, said pinchings determining four vertical ribs 15 protruding toward the tubing interior and forming inside the tubing, a guide and centering seat for a threaded shank 16 whereon a height adjusting nut 17 is threaded, which, with its top face 18, bears the lower edges 19 of the walls 22 of the square tubing. Due to the presence of the pinchings 14, the foot square tubing forms four ribs 20 at the lower corners thereof. At the lower end of said threaded shank 16 there is associated, for example by welding, a ribbed rest plate 21 which forms the foot base. Upwardly after hooking each moulding 1 to a respective wall 22 by slipping the upper edge of each wall in the spaces 7 of the respective moulding 1, a lockscrew 23 may be inserted from above in the recesses formed by the tips of the triangular zones 4. Then the lockscrew 23 is threaded over an inverted-U elastic element 25 inserted preliminarly into the upper portion of the square tubing, until the lockscrew head 24 rests in the recessed seats 9 previously described. To prevent said elastic element 25 from sinking too far into the tubing when the screw is threaded in, the walls 22 present at least two turned in wings 26 opposite to each other and obtained by shearing or dimpling the walls 22, said wings 26 forming rest means for the element 25. Preferably the elastic element 25 is arcuate, thereby under the action of the screw 23 it expands interfering with the inner walls of the foot square tubing and thus improving the connection among the crosspieces and the foot. The screw 23 on the one side makes rigid with each other the four crosspieces 1 converging all on a same foot 13 and on the other side lock the heads of the crosspieces also with respect to the upper portion of the foot square tubing. To improve the electrical continuity of the structure, the holes 10 may accommodate small bolts 27 interconnected by metal bridges or chains 28. From what has been described and illustrated, it may be seen that the resulting structure is particularly simple both from the constructional viewpoint of the various components and the assembling viewpoint. The crosspiece is greatly simplified and hooking on the foot is accomplished without the latter being equipped with any particular plate device as is usual the case with previously known feet. The four crosspieces converging on one foot practically determine total closure of its upper portion, which closure is completed and secured by the plastics mouldings which are then superimposed on the crosspieces themselves. This involves a perfect closure of the section of the square tubing and prevents any passage of air stream which could generate between the lower portion and the upper portion of the floor. This aspect is particularly advantageous in that below raised floors obtained with equivalent structures to the one illustrated, room conditioning air is usually introduced which of course is to get out solely where special outlets are provided but should not leak through the joints of the individual panels. The structure lends itself well also for arrangement against the walls of the room because three, or two in the case of a corner, crosspieces would be anyhow firmly and individually hooked on each foot which may be laid against the wall without having to break, saw or anyhow eliminate parts thereof. Hooking of each crosspiece obtained with the turned over lugs 5 cooperating with the wings 8 present in each head, is particularly strong, so that it is possible to hook crosspiece sections, working cantilever-fashion, for the necessary completions of the floors along the walls. The covering of each crosspiece obtained with the plastics mouldings, completely isolates the floor panels from the underlying metal structure with clear safety advantages particularly in connection with any current losses which may occur in the event of failures or damage to the cables running under the floor. The electric continuity which is accomplished in the structure by means of the center screw and the metal bridges, allows grounding of the entire structure by connecting at least one point thereof to a sink. The crosspieces are formed simply by shearing and pressing from sheet metal and the foot is just as simply composed of a section of square tubing cooperating with a threaded shank with rest plate welded to one of its ends. In the event that it becomes necessary to increase the strength of the structure, the crosspiece may be made with a closed profile e.g. rectangular cross-section tubing. Height adjustment is simply accomplished by acting on the nut 17 threaded over the shank 16 and constituting rest for the lower face of the square tubing. Therefore, as explained,a load-bearing structure for raised floors has been provided which is composed of very simple and functional parts, the assembling whereof is particularly easy since it requires no tools nor for positioning the feet nor for locking the crosspieces. Of course, starting from the same inventive concept, others may be the practical constructional forms that the structure may take while retaining the same concepts of hooking, locking and adjusting the crosspieces and feet as described in the appended claims.

Claims: A load-bearing structure for raised floors of the type comprising rest feet (13) and connecting crosspieces (1) converging to said rest feet to form a supporting grid for modular panels, said rest feet (13) consisting of sections of tubing mounted vertically on ground rest plates (21), said crosspieces (1) being provided at the opposite heads thereof with hooking means for connecting the ends of the crosspieces converging to a common rest foot (13) with each other and with said common rest foot, the arrangement being such that the heads of the crosspieces (1) converge to one rest foot (13), with the adjacent hooking means of the converging crosspieces (1) in interengagement for securement thereof against horizontal movement with respect to each other and with respect to the associated foot, there being further provided locking means (23-25) for securing said hooking means to the associated feet (13), said locking means cooperate with said hooking means for securing the heads of said crosspieces against vertical detachment thereof from the associated foot, characterized in that said crosspieces are shaped profiles (1) in sheet metal having at least one upper face (2) and vertical sides walls (3), said sections of tubing having a substantially square cross-section, said hooking means comprising a substantially triangular longitudinal extension (4) of said upper face (2) which is adapted to overlay one quarter of the square section of an associated foot and is provided with a pair of metal sheet lugs (5) turned over from the outer edges of said triangular extension (4) and formed integrally therewith to provide a rigid, arrow-like projection, each head of the crosspieces being further provided with a pair of lateral wings (8) extending below said lugs (5) and projecting inwardly and oppositely from said vertical sides (3) to abut against the outer wall of an associated foot rest, there being further provided sealing means (11) for covering at least the upper face (2) of said crosspieces up to said triangular extension thereof, and means (16, 17) for adjusting the heigth of said foot relative to the ground. A structure according to Claim 1, characterized in that said locking means comprise a recess (9) formed at the tip of said triangular extension (4) to define a seat for a lockscrew (23) arranged vertically and in threaded engagement with a retaining element (25) of substantially inverted U-section, said retaining element being located internally of an associated foot (13) and being arcuate to expand against the inner walls of said foot when acted upon by said lockscrew (23). A structure according to any one of the preceding claims, characterized in that said means for adjusting the useful height of each foot (13) comprise at the lower end thereof an inwardly squeezed portion (14) defining centrally protruding ribs (15), said ribs being so adapted to provide guide seats for a threaded shank (16) extending axially of said tubing section and cooperating with an adjustement nut (17), between said inwardly directed ribs (15) there being provided outwardly projecting corners (20) having lower ends (19) adapted to bear against said adjustment nut (17). A structure according to any one of the preceding claims, chacaterized in that said crosspieces (1) have an open profile of substantially inverted U-shaped section. A structure according to any one of the preceding claims, chacaterized in that said crosspieces (1) have a closed profile of substantially square or rectangular section. A structure according to any one of the preceding claims, chacaterized in that said sealing means (11) comprise moulded elements preferably in plastic material, having substantially inverted U-shaped section adapted to cover the upper face (2) of said crosspieces and to partially embrace the vertical sides (3) thereof. A structure according to any one of the preceding claims, chacaterized in that it further comprises electrical connection means (10, 27, 28) for electrically connecting said crosspieces (1) with each other and for allowing grounding of the whole structure through connection with a sink.

Inventors: CATALANO, COSIMO, PASTO' PAOLO
Applicants: HIROSS S.P.A.
Application year: 1986
Main classification: E04F15
IPC codes: E04F15