EP1598498A1

EP1598498A1 - Connecting stake with a fixing stirrup with clamps, for the assembly of a concrete floor on wooden beams

Info

Publication number: EP1598498A1
Application number: EP05075855A
Authority: EP
Inventors: Francesco Guazzo
Original assignee: Tecnaria SpA
Current assignee: Tecnaria SpA
Priority date: 2004-05-20
Filing date: 2005-04-12
Publication date: 2005-11-23
Also published as: ITVI20040123A1

Abstract

The finding substantially concerns an improvement of the finding described in European patent no. 0742323, which concerns a connecting stake, comprising a cylindrical rod (1), fixed to a base plate (3), equipped with holes (5, 6) which act for fixing, in particular through screws, to a wooden beam. According to the finding it is foreseen that said holes (5, 6) are shaped so as to allow the screws (7) inserted in them to be positioned stably.

Description

The present finding essentially concerns an improvement to the connecting stake with a fixing stirrup with clamps, for the assembly of concrete floors on wooden beams, described in European patent no. 0742323, to the same Applicant.

It is known that for some time the construction of structures made up of wood and concrete has been in use, particularly for making concrete slabs supported by wooden beams. The European patent quoted above allows a connecting stake equipped right from the start with a fixing stirrup with clamps to be made, which can be mounted on a wooden beam for a stable and long-lasting fastening to an element made from concrete.

Such a patent foresees, in particular, a connecting stake, consisting of a cylindrical rod, equipped with an enlarged head, as well as a square base plate with corners bent down.

The fastening of this structure onto the wooden structure is carried out by screwing or another analogous mechanical fastening method, so as to make the fixing members penetrate in the wooden beam, in which the bent down corners of the plate act as clamps, which firmly stabilise the fastening of the stake to the wooden beam.

Such a device is simple from the constructive point of view and also its fastening does not require the use of long and complex operations, such as the removal of wooden material, the insertion of bicomponent resins, the insertion of rods or other, foreseen in previously known devices.

However, the device according to the quoted patent also has the drawback due to the fact that in order to be able to effectively ensure that the structure is fixed to a wooden beam and therefore to a concrete slab, it is advantageous to use screws as fasteners that have a threaded portion, which inserts into the concrete part and that has a slightly greater external diameter than the end portion of the screw itself, which is, vice-versa, smooth and which is arranged itself, which is, vice-versa, smooth and which is arranged close to the head of the screw and which, in operating conditions, goes right at the hole in which the screw itself is inserted.

This means that there is a certain clearance, although low, but still noticeable, between the outer surface of the unthreaded portion of the screw and the inner surface of the hole in which it is inserted, which determines a possibility of low, but still noticeable sliding between the screw and the plate, even for low stress values.

This is, of course, disadvantageous, since with such a device it is not possible to ensure a perfect seal by the plate of the various elements that make up the structure.

The purpose of the present finding is that of foreseeing a device that is able to avoid this drawback, allowing, in particular, a perfect adhesion between stem of the screw and plate in which it is inserted, avoiding any possible sliding between the aforementioned two elements.

This is obtained, according to the finding, by foreseeing that the holes in which the screws are inserted, as well as the portions of the stems of the screws situated near to the heads thereof, have a frusto-conical profile. In this way, by forcefully inserting the screw in its seat, the screw is stably fixed in the seat.

These and other characteristics of the finding shall now be described in detail, with reference to a particular embodiment thereof, given as a non-limiting example, with the help of the attached tables of drawings, where:

fig. 1 illustrates a side view of the connecting stake, with the base plate sectioned;
fig. 2 represents the side view of the aforementioned stake;
fig. 3 illustrates a plan view from above of the aforementioned stake;
fig. 4 illustrates a detail of the connection area between plate and fastening screw.

As can be seen from the attached figures, the connecting stake consists of a cylindrical rod 1, equipped with an head 2 with enlarged diameter, advantageously obtained by cold deformation, and with a plate 3, advantageously square, equipped with corners 4 bent down, which can advantageously be obtained through cold bending of the aforementioned plate. The plate is equipped with two

holes

5 and 6, in which the fixing elements can be introduced.

Indeed, the fixing on the underlying wooden structure (not illustrated in the figures) is in this case carried out through screwing, thanks to a screw 7 (figure 4). It is also foreseen that the corners 4 of the plate 3, bent down, which act as clamps, are suitable for firmly stabilising the fastening of the stake to the wooden beam.

A fundamental characteristic of the device according to the finding consists of the fact that, as can clearly be seen in figure 4, the

holes

5 and 6 are frusto-conical shaped, with the portion with a smaller section facing downwards, just as an analogous configuration is foreseen at the portion 8^I of the stem 8 of the screw 7 closest to the head 9 thereof.

In this way, two contrasting requirements are reconciled:

the first, consisting of the need to foresee a sufficiently large hole, also at its narrowest portion (the lower portion), to allow the easy passage of the threaded portion 8^II of the screw 8, which, clearly, has a slightly greater external diameter than the unthreaded portion thereof;
the need to ensure a stable contact between the portion of the screw arranged inside the holes 5 and 6 and the inner walls of the aforementioned holes, to avoid the possibility of even minimal sliding in the transversal direction of the head of the screw, which, in similar known devices, can cause problems for the stability of the entire fixing unit.

Moreover, it is possible to foresee a particular embodiment suitable for ensuring a more effective firm fitting between the rod 1 and the plate 3. Indeed, as can be seen in figure 1, the portion 1^I of the rod 1 that goes into contact with the plate 3 is double frustum of cone shaped 1^II, 1^III, whereas the plate has a hole in which one of the ends of the rod is inserted, the edges of said hole 3^I going into the contact area between the two frustums of

cone

1^II and 1^III. Above said two elements the rod has a widened area 1^IV, which traps the edges 3^I of the hole present in the plate 3, avoiding any possible oscillation of the rod with respect to the plate.

It can thus be seen how through the device according to the finding it is possible to quickly, securely and cost-effectively obtain the assembly of a concrete floor on wooden beams.

Claims

CONNECTING STAKE WITH A FIXING STIRRUP WITH CLAMPS, FOR THE ASSEMBLY OF A CONCRETE FLOOR ON WOODEN BEAMS, of the type comprising a cylindrical rod (1), equipped with an upper head (2) with enlarged diameter, the opposite end of which is fixed to a shaped plate (3), equipped with a pair of holes (5, 6) suitable for allowing the passage of the stem of a screw (7), on which the concrete floor is then laid, which completes the structure, also foreseeing clamps, obtained by bending the corners (4) of the base plate, suitable for firmly penetrating in the wooden beam below, the connecting stake being characterised in that the holes (5, 6) are frusto-conical shaped, with a smaller section at the surface of the plate that is arranged towards the wooden beam, with it also being foreseen that the portion (8^I) of the stem (8) of the screw (7) situated close to the head (9) is frusto-conical shaped.
CONNECTING STAKE, according to claim 1, characterised in that the portion (1^I) of the rod (1) that goes into contact with the plate (3) is double frustum of cone shaped (1^II, 1^III), whereas the plate has a hole in which said portion (1^I) inserts, the edges (3^I) of said hole going into the contact zone between the two frustums of cone (1^II, 1^III), with it being foreseen that, above said two elements, the rod has a widened area (1^IV), that traps said edges (3^I), avoiding any possible oscillation of the rod (1) with respect to the plate (3).