ES2354336B1 - CLAMP FOR THE CONNECTION AND FIXATION OF A REINFORCEMENT ELEMENT TO A SUPPORT PILLAR. - Google Patents

Abstract

Clamp for the connection and fixation on a scaffold of a reinforcement element to a support pillar. # The clamp comprises a fixed and a mobile jaw pivotally joined, and a sliding wedge through the fixed jaw to open and close the clamp. The distal ends of the jaws are configured to firmly clamp and in the operative closing position of the clamp, one of the longitudinal projections of the abutment. In addition, elastic means act permanently between the jaws to keep their ends separated by adopting the clamp in an open position in the absence of external forces. The clamp adopts a stable intermediate operating position in which it holds the projection with some slack, by manually exerting a predetermined force of mutual approach on the jaws that makes the wedge slide, by gravity, in the fixed jaw, preventing the wedge from returning from the clamp to the open position.

Description

usually by a lower horizontal bar and a

Clamp for the connection and fixation in scaffolding of a reinforcement element to a support pillar. Technical sector of the invention

The present invention relates to a clamp for the connection and fixation on scaffolding of a reinforcing element, such as a bracing frame, to a vertical support or pillar element, provided with longitudinal projections and grooves.

The clamp comprises a fixed clamping jaw, a mobile clamping jaw pivotally joined and facing the previous one, and a wedge of sliding drive through the fixed jaw for rotation of the movable jaw for opening and closing the clamp. The distal ends of the clamping jaws are configured to clamp firmly in the operative position of the clamp, one of the projections of which the abutment is provided. Background of the invention

In the sector of the construction of tubular scaffolding it is usual to place reinforcement elements, such as bracing in the form of horizontal, diagonal bars or bracing frames to maintain the verticality of the scaffolding. The ends of said reinforcement elements are coupled with connection and fixing devices, clamps generally consisting of two clamping jaws that embrace and are attached to respective vertical support elements of the scaffold, also called pillars. In addition, to set the opening between the jaws tightly, these devices are usually provided with a wedge.

In particular, some pillars, adjustable in height, have an outer tube and an inner tube whose cross section distinguishes projections and recesses that serve as gripping elements for said connection and fixing clamps. Patents ES2140598-T3 and ES2090717-T3 disclose support scaffolding with abutments of the type described, as well as fixing means in the reinforcement constituted by a clamp provided with two clamping jaws opposed to each other and con fi gured in such a way that it can engage both behind the projections or projections of the outer tube and also behind those of the inner tube. The narrow fastener in which the jaw hugs the protrusions of the inner tube is fixed by means of a clamp wedge while the slightly wider fastener to embrace the protrusions of the outer tube is performed by the same wedge but at another stage.

Another example of a connection and fixing device is that described in US5713687, formed by two jaws whose closing movement is caused by tensioned means con fi gured as a wedge with ribs that run diagonally along it. The ribs work together with a series of teeth arranged in the mobile jaw and the wedge has a curved cross section. When the wedge is introduced, with the help of a hammer, passing through through holes made in the fixed jaw, the teeth of the mobile jaw that are guided in the ribs of the wedge cause, by following the diagonal path of the ribs, which the movable jaw rotates with respect to the fixture making the opening between the ends of said jaws narrower.

upper horizontal bar parallel and joined together by one or several vertical or diagonal bars. In order for said frame to be placed between two support pillars of the scaffold in order to bracing them, it is necessary that the four ends of the frame be provided with respective connection and fixing devices.

It must be taken into account that during the installation of the frame, the operator must hold the frame with one hand, approaching the connection clamps on one side to the pillar to which it will be connected. In the connection devices described above, the weight of the fixing wedges, arranged in a vertical direction, means that from the beginning the jaws are touching each other, in a closed position and that the operator has to extract by hand free part of the wedge to get the jaws open enough to embrace one of the protrusions of the tube that constitutes the pillar. Subsequently, the opening is adjusted by introducing the wedge down until the two jaws are fixed to said projection.

In the situation described above it would be desirable that the operator could have both hands to hold the bracing frame, since handling and orienting it towards the projections with one hand is not comfortable and that it was equally easy to immediately attach the frame to the pillars . Thus, the need for a connection and fixing clamp is made evident by means of which it is easy and convenient to connect and secure a reinforcing element to a scaffold pillar. Explanation of the invention.

In order to provide a solution to the problems raised, a clamp for connecting and scaffolding a reinforcement element to a support pillar of those provided with longitudinal projections and grooves is disclosed. The clamp comprises a fixed clamping jaw, a mobile clamping jaw pivotally joined and facing the previous one, and a sliding wedge sliding through the fixed jaw for rotation of the movable jaw for opening and closing the clamp, the distal ends of the clamping jaws facing each other and being configured to clamp firmly and in the operative closing position of the clamp, one of the projections of the abutment.

In essence, the clamp object of the invention is characterized in that it comprises elastic means that act permanently between the two jaws and tend to keep their distal ends separated from each other, the clamp adopting an open operative position in the absence of external forces, the adapters being adapted contact surfaces between the wedge and the movable jaw so that the clamp is capable of adopting a stable intermediate operating position in which it holds the pillar projection with some clearance, by manually exerting a predetermined force of mutual approach on the jaws that causes the sliding of the drive wedge, due to the effect of gravity, on the fixed jaw, preventing the wedge from returning the clamp to the open position.

According to another characteristic of the invention, the elastic means act permanently on compression on the two jaws.

According to another feature of the invention, the elastic means are constituted by a torsion spring coupled to the axis of rotation of the movable jaw with respect to the fixed jaw and whose ends are fixed to a respective jaw.

According to another feature of the invention, the fixed jaw is formed by two side walls essentially parallel to each other and perpendicular to a base that joins them, said base being provided, at the first end of the jaw, with an protruding flange facing the first end of the mobile jaw.

According to another characteristic of the invention, the movable jaw is in the form of a bent strip, provided with two essentially flat arms parallel to the side walls of the fixed jaw, connected at one end to a joint portion provided with a flange facing the first end of the fixed jaw.

According to another feature of the invention, at least one of the arms of the movable jaw is pivotally attached to one of the side walls of the fixed jaw and is arranged at all times with one of its edges in contact with the inclined side of the wedge of fixation, said song comprising at least one curved profile.

According to another feature of the invention, the contour of at least one of the arms of the mobile jaw comprises two contiguous curved convex sections followed by a straight section.

According to another feature of the invention, the fixed jaw is provided with coupling means for coupling the reinforcement element to the abutment, formed by two through holes provided on the side walls of the fixed jaw, intended to be pierced by a bolt. or tightening screw that attaches the end of the jaw to a reinforcing element.

Preferably, the angle of the fixing wedge is between 5 ° and 15 °. Brief description of the drawings

The attached drawings illustrate, by way of non-limiting example, a preferred embodiment of the connection and fixing clamp object of the invention. In these drawings:

Figs. 1 and 2 are plan views of a support pillar of a scaffold and of the clamp object of the invention coupled to a reinforcing element, said clamp being in the open and closed position, respectively;

Figs. 3 and 4 are perspective views of the clamp in the stable intermediate operating position;

Fig. 5 is a profile view of one of the arms of the mobile jaw;

Figs. 6 and 7 are detailed views of the ends of the arms of the mobile jaw with the clip being in the stable intermediate operating position;

Fig. 8 is a perspective view of a bracing frame provided at its four ends with respective clamps arranged in the stable operating and intermediate position;

Fig. 9 is a perspective view of a bracing frame like that of Fig. 8 but with the clamps in operative position closed;

Figs. 10 and 11 are detailed views of the pliers of Fig. 9;

Fig. 12 is a perspective view of a bracing frame like that of Fig. 8 but with the clamps in open position; Y

Figs. 13 and 14 are detailed views of the pliers of Fig. 12. Detailed description of the drawings

In Figs. 1 and 2 shows the connecting and fixing clamp 1 coupled at one end to a reinforcement element 2 (partially shown) such as a bracing frame, in the open position and in the closed position, respectively, in relation to a pillar 3 of scaffolding support.

A scaffold basically consists of a series of supporting pillars 3, adjustable in height and constituted by an outer tube and an inner tube, with reinforcement elements 2 and connecting and fixing clamps 1 arranged between said pillars 3 for the union of the inner tube or outside with the reinforcing element 2. In Figs. 8,9 and 12 a reinforcement element 2 in the form of a bracing frame is observed, at whose ends respective clips 1 are connected to connect and fix said bracing frame to two pillars 3 (not shown). As seen in Figs. 3 and 4, the clamp 1 is provided with coupling means formed by two through holes 17 provided on the side walls 10 and 11, intended to be traversed by corresponding bolts or clamping screws 18 (see Figs. 10, 11, 13 and 14) adapted to make the coupling of the clamp 1 to the reinforcement element 2.

As seen in Figs. 1 and 2, the cross-section of the support pillar 3 is provided perimetrically with four projections 20, anchored by respective grooves, which extend entirely or partially, along the pillar 3. It is precisely of the projections 20 from which grab the clamp 1 to make the connection and fixation of a bracing frame, as shown in Figs. 8, 9 and 12, or any other reinforcement element 2, to the corresponding pillars 3.

As particularly seen in Figs. 3 and 4, the connecting and fixing clamp 1 comprises a fixed clamping jaw 4 and a movable clamping jaw 5 pivotally joined together, so that the movable jaw 5 can rotate with respect to the fixed jaw 4 around the axis of rotation 9. The distal ends of the fixed jaw 4 jaws 5 are arranged facing each other and configured to clamp firmly and in the operative closing position of the clamp 1 one of the projections 20 of the pillars 3, as discussed above. In particular, said distal ends are provided with respective flanges 13 and 16 (see Figs. 1, 2,3 and 4) that pass behind a corresponding projection 20 being pressed against it and arranged in the grooves of the sides when the clamp 1 is in the closed position (see Figs. 2, 9, 10 and 11).

The fixed jaw 4 is formed by two side walls 10 and 11 essentially parallel to each other and perpendicular to the base 12 that joins them. In turn, it is the base 12 that is provided, at the first end of the jaw, with the flange 13 protruding and oriented towards the distal end of the movable jaw 5.

The mobile jaw 5 is in the form of a bent strip and is constituted by two arms 14 a and 14b essentially flat and parallel to the side walls 10 and 11 of the fixed jaw 4, joined by one of its ends to a joint portion 15 where tab 16 is provided.

The clamp 1 also comprises a wedge 7 of sliding drive through the fixed jaw 4, perpendicular to the side walls 10 and 11 provided with rectangular through holes suitable for the passage of the wedge 7, for the opening and closing of the clamp 1. On the wedge 7, at the end of the inclined side 8, a first end and a second end are distinguished, the second being wider than the first and on which the force necessary to insert the wedge 7 into the holes is applied of the fixed jaw 4. The first end of the wedge 7 is provided with a through hole pierced by a bolt, bolt or similar element that contributes to increasing the thickness of said end so that said first end cannot pass through the rectangular through hole of the lateral wall 11 of the fixed jaw 4, making sure that the wedge 7 will always be inserted in greater

or to a lesser degree in the fixed jaw 4.

The sliding of the wedge 7 causes the clamp 1 to adopt a closed position to fix the reinforcing element 2 to the supporting pillar 3 (see Figs. 2, 9, 10 and 11) when the wedge 7 is set to the maximum, situation in which the tabs 13 and 16 are pressed against the rear part of the projection 20 of the pillar 3. The opposite situation to the previous one is when the fixing wedge 7 is removed to the maximum with respect to the fixed jaw 4, adopting the open operating position shown in Figs. 13 and

14. In the open operating position, it is observed how the first end of the wedge 7, and in particular the bolt

or the end robber bumps against the side wall 11 of the fixed jaw 4.

In addition to the operative closing position and the open position, the clamp 1 can also adopt a stable intermediate operating position, represented in Figs. 3, 4 and 8, in which the wedge 7 is partially inserted in the fixed jaw 4, halfway between the open position and the closed position. The usefulness of this stable intermediate position is that the clamp 1 is placed or coupled, but not firmly fixed, to the pillar 3 as will be described later.

The clip 1 also comprises elastic means 6 that act permanently between the two jaws 4 and 5 and tend to keep their distal ends separated from each other by adopting the clip 1 the operative position open in the absence of external forces, a situation represented in Figs. 1, 12, 13 14. Said elastic means, according to the example shown, act permanently on compression on the two jaws 4 and 5 and are constituted by a torsion spring coupled to the axis of rotation 9 of the movable jaw 5 with respect to the fixed jaw 4 and whose ends are coupled to a respective jaw.

As mentioned above, the clamp 1 can adopt a stable intermediate operating position in which it holds with some clearance the projection 20 of the pillar 3, and this is produced by manually exerting a predetermined force of mutual approach on the two jaws 4 and 5 , which causes the wedge 7 to slide, due to gravity, in the fixed jaw 4 and the wedge 7 itself prevents the return of the clamp to the open position.

Thanks to the elastic means 6 keeping the clamp 1 in the open position, in the absence of external forces on the wedge 7, the positioning of the reinforcing element in the support pillars 3 of the scaffold is convenient and simple.

Starting from Fig. 12, the user will take the bracing frame with both hands and bring, for example, the two clamps 1 on the left to a support pillar 3 (not shown). The two clamps 1 will be open due to the action of the elastic means 6 on the jaws 4 and 5. Subsequently, with one hand it will press both the fixed jaw 4 and the mobile jaw 5 to force them to approach it until the wedge 7 of the clamp 1 falls from top to bottom, due to the effect of gravity, clamp 1 adopting the stable intermediate operating position (see Figs. 3, 4 and 8), at which time it will no longer be necessary to continue tightening the jaws 4 and 5 because the Wedge 7 itself will prevent the return to the open position.

In the stable intermediate position, the wedge 7 is partially inserted into the fixed jaw 4 such that the distal ends of both jaws 4 and 5 embrace one of the projections 20 of the pillar 3, but without exerting too much pressure on said projection. Thus, when proceeding in the same way with the lower clamp 1 on the left, the user will have sufficient room for maneuver to place the lower clamp on the pillar 3 without being prevented by a strong fixation of the upper clamp 1. To finish placing the bracing frame, we will also proceed with the two clamps 1 on the right, making them adopt the stable intermediate operating position. Once the bracing frame is placed, with the four clamps 1 in stable intermediate operating position, pressure will be exerted on the wedges 7, with the help of a hammer or similar tool until the clamps 1 adopt the closed position shown in Figs . 2, 9, 10 and 11, with its position firmly fixed with respect to the two pillars 3. As expected, to decouple the bracing frame of the pillars 3, proceed in reverse and it is also advisable to go through the position Stable intermediate operation to be able to unfasten the four clamps 1 comfortably, before moving to the open position.

In the example of the clamp 1 shown in the figures, the two arms 14a and 14b of the movable jaw 5 are connected at one end to the fixed jaw 4, and one of its edges remains in contact with the inclined side 8 of the drive wedge 7, as seen in Figs. 6 and 7. In Fig. 7 it can be seen that the arm 14a has a curved profile 22 that remains in contact with the inclined side 8 of the wedge 7 in any of the three positions of the clamp 1 described above.

For its part, the arm 14b has an outline that has two contiguous curved-convex sections 19 and 20 followed by a straight section 21, as shown in Fig. 5 Fig. 6.

The straight section 21 acts as a limiting safety against excessive opening of the clamp 1 in the open position. When the inclined side 8 of the wedge 7 contacts the intermediate part of the curved convex section 20, the clamp 1 is in the intermediate operating position, and when the contact is made between the two contiguous curved-convex sections 19 and 20, the clamp 1 it is in the closed operating position (for which wedge 7 will have been introduced with the help of a hammer or similar tool).

In summary, the clamp 1 is convenient to handle and offers a simple means to couple and secure a reinforcing element 2 to a supporting pillar 3 of those provided with projections 20 and longitudinal grooves since it facilitates the task of coupling the reinforcing element to be able to place with some slack the bracing frames on the pillars 3 simply by squeezing the jaws 4 and 5 of the clamp 1, without tools. At a later stage, when the bracing frame to the pillars 3 is finally de fi ned, the wedge 7 will be introduced until the end by hitting it with the help of a hammer.

Claims (10)

1. Clamp (1) for the connection and fixation on scaffolding of a reinforcement element (2) to a support pillar (3) provided with projections (20) and longitudinal grooves, comprising a fixed jaw (4) of clamping, a movable jaw (5) pivotally attached and facing the previous one, and a wedge (7) of sliding drive through the fixed jaw for the rotation of the mobile jaw for opening and closing of the clamp, the distal ends of the clamping jaws facing each other and configured to clamp firmly and in position operative closure of the clamp, one of the projections of the abutment, characterized in that it comprises elastic means (6) that act permanently between the two jaws and tend to keep their distal ends separated from each other by adopting the clamp an open operative position in the absence of external forces, the contact surfaces between the wedge and the movable jaw being adapted so that the clamp is capable of adopting a stable intermediate operating position in which it holds with some clearance to the projection of the abutment, by manually exerting a predetermined force of approach mutual over the jaws that causes the drive wedge to slide, po The effect of gravity, on the fixed jaw, prevents the wedge from returning the clamp to the open position.

2.

Clamp (1) according to claim 1, characterized in that the elastic means (6) act permanently on compression on the two jaws.

3.

Clamp (1) according to claim 2, characterized in that the elastic means (6) are constituted by a torsion spring coupled to the axis of rotation

(9) of the mobile jaw (5) with respect to the fixed jaw (4) and whose ends are fixed to a respective jaw. 4. Clamp (1) according to any one of the preceding claims, characterized in that the fixed jaw (4) is formed by two side walls (10, 11) essentially parallel to each other and perpendicular to a base (12) that joins them, being said base provided, at the first end of the jaw, with an protruding flange (13) oriented towards the first end of the mobile jaw (5).

5.

Clamp (1) according to claim 4, characterized in that the movable jaw (5) is in the form of a bent strip, provided with two arms (14a, 14b) essentially flat and parallel to the side walls (10, 11) of the fixed jaw ( 4), joined by one of its ends to a connecting portion (15) provided with a flange (16) oriented towards the first end of the fixed jaw (4).

6.

Clamp (1) according to claim 5, characterized in that at least one of the arms (14a, 14b) of the movable jaw (5) is pivotally connected to one of the side walls (10, 11) of the fixed jaw (4) and is disposed at all times with one of its edges in contact with the inclined side (8) of the wedge (7) of fixation, said edge comprising at least one curved profile (20, 22).

7.

Clamp (1) according to claim 6, characterized in that the contour of at least one of the arms (14b) of the mobile jaw (5) comprises two contiguous curved-convex sections (19, 20) followed by a straight section (21) .

8.

Clamp (1) according to any one of the preceding claims, characterized in that the fixed jaw (4) is provided with coupling means for coupling the reinforcing element (2) to the pillar (3), formed by two holes

(17) passages provided on the side walls (10, 11) of the fixed jaw (4), intended to be traversed by a bolt or clamping screw (18) that joins the end of the jaw fixed to a reinforcing element ( 2). 9. Clamp (1) according to any one of the preceding claims, characterized in that the angle of the wedge (7) is between 5 ° and 15 °. SPANISH OFFICE OF THE PATENTS AND BRAND Application no .: 200901157 SPAIN Date of submission of the application: 07.05.2009 Priority Date: REPORT ON THE STATE OF THE TECHNIQUE 51 Int. Cl.: E04G7 / 30 (01.01.2006) RELEVANT DOCUMENTS

Category

Documents cited Claims Affected

Y

US 5713687 A (SCHWOERER ARTUR) 03.02.1998, column 2, lines 51-60; column 3, line 36 - column 4, line 28; Figures 1-3. 1,2,4-6,8,9

Y

EP 0445014 A1 (ROUX MARCEL HENRI RENE) 04.09.1991, column 4, line 42 - column 6, line 2; Figures 1-4. 1,2,4-6,8,9

TO

US 2004 211 147 A1 (VANAGAN PETER) 28.10.2004, paragraphs [0046-0050]; Figures 12-16 1,4,8

TO

EP 1134332 A1 (WILIAN HOLDING CO) 19.09.2001, paragraphs [0011-0017]; Figures 3a, 3b, 4. 1,4,8

TO

EP 0276489 A1 (LANGER RUTH GEB LAYHER) 03.08.1988 & Summary of the WPI database. Recovered from EPOQUE; AN 1988-213975; figure 3. 1-3

Category of the documents cited X: of particular relevance Y: of particular relevance combined with other / s of the same category A: reflects the state of the art O: refers to unwritten disclosure P: published between the priority date and the date of priority submission of the application E: previous document, but published after the date of submission of the application

This report has been prepared • for all claims • for claims no:

Date of realization of the report 02.28.2011

Examiner S. Fernández de Miguel Page 1/4

REPORT OF THE STATE OF THE TECHNIQUE Application number: 200901157 Minimum documentation searched (classification system followed by classification symbols) E04G Electronic databases consulted during the search (name of the database and, if possible, terms of search used) INVENES, EPODOC State of the Art Report Page 2/4  WRITTEN OPINION Application number: 200901157 Date of Completion of Written Opinion: 02.28.2011 Statement

Novelty (Art. 6.1 LP 11/1986)

Claims Claims 1-9 IF NOT

Inventive activity (Art. 8.1 LP11 / 1986)

Claims 3.7 Claims 1,2,4-6,8,9 IF NOT

The application is considered to comply with the industrial application requirement. This requirement was evaluated during the formal and technical examination phase of the application (Article 31.2 Law 11/1986).  Opinion Base.- This opinion has been made on the basis of the patent application as published. State of the Art Report Page 3/4  WRITTEN OPINION Application number: 200901157 1. Documents considered.- The documents belonging to the state of the art taken into consideration for the realization of this opinion are listed below.

Document

Publication or Identification Number publication date

D01

US 5713687 A (SCHWOERER ARTUR) 03.02.1998

D02

EP 0445014 A1 (ROUX MARCEL HENRI RENE) 04.09.1991

D03

US 2004 211 147 A1 (VANAGAN PETER) 10/28/2004

D04

EP 1134332 A1 (WILIAN HOLDING CO) 19.09.2001

D05

EP 0276489 A1 (LANGER RUTH GEB LAYHER) 03.08.1988

2. Statement motivated according to articles 29.6 and 29.7 of the Regulations for the execution of Law 11/1986, of March 20, on Patents on novelty and inventive activity; quotes and explanations in support of this statement The present invention relates to a clamp for the connection and fixation on scaffolding of a reinforcing element to a support pillar provided with longitudinal projections and grooves. The clamp comprises a fixed jaw and a pivotally movable clamping jaw, as well as a sliding drive wedge through the fixed jaw for opening and closing the clamp. The distal ends of the jaws are configured to clamp firmly, and in the operative position of the clamp, one of the projections of the abutment. Documents D01 and D02 are considered the state of the art closest to the object of claim 1 of the application. Document D01 discloses a clamp for the connection of a reinforcement element (1) to a telescopic abutment (2) provided with projections (6.8) and longitudinal grooves (5,7). The clamp comprises a fixed jaw (11) and a mobile jaw (20) pivotally joined to the previous one and a wedge (23) slidable through the fixed jaw for the rotation of the mobile jaw in order to produce the opening and closing of the clamp The distal ends (9,10) of the clamping jaws are facing each other and configured to firmly clamp, in the position of the clamp, one of the projections of the abutment. The contact surfaces between the wedge and the movable jaw are adapted so that the clamp is capable of adopting a stable intermediate operating position in which it holds with some clearance the projection of the abutment by exerting a predetermined force that causes the wedge to slide of actuation in the fixed jaw preventing the return of the clamp to the open position (see column 2, lines 51-60; column 3, line 65-column 4, line 28; figure 1) The difference between document D01 and the subject The technique of claim 1 is that said document does not show elastic means that act permanently between the two jaws. The technical problem underlying the present application can be established as the provision of means to keep the distal ends of the jaws apart from each other by adopting the clamp in an open operating position in the absence of external forces. However, this problem and its solution are already included in document D02 which describes a clamp for connecting a reinforcement element (2) to a pillar (1) provided with projections (3) and longitudinal grooves (4). The clamp has a pair of jaws (6) and a drive wedge (9), comprising elastic means (11) that act permanently between the two jaws adopting the clamp an open position in the absence of external forces (see column 5, lines 15-31; figure 2). It would be obvious to one skilled in the art to combine documents D01 and D02 and arrive at the invention as defined in claim 1. Claim 2 describes the mode of operation of the elastic means and is considered anticipated by document D02. In relation to claim 4, document D01 has a fixed jaw with a "U" section that differs only from the one claimed in that said section is rounded, therefore its sides or side walls are not perpendicular to the base. For a person skilled in the art, this configuration, which is already known from documents D03 and D04, would be obvious, thus making this difference irrelevant. Claims 5, 6 and 9, referring respectively to the characteristics of the movable jaw and the angle of the fixing wedge are also anticipated by document D01. Finally, claim 8 describes the coupling means to the reinforcing element. Said means are widely known in the state of the art as can be seen in documents D03 and D04. For all the foregoing, the invention defined in claims 1,2, 4-6, 8 and 9 derives from the state of the art in an obvious way for a person skilled in the art and does not imply inventive activity (Law 11/1986, Art. 8.1). State of the Art Report Page 4/4