EP0716195B1 - Mechanical connection for concrete reinforcing rods, device for installing this mechanical connection and process for fixing mechanical connections for concrete reinforcing rods - Google Patents

Abstract

A mechanical connection for concrete reinforcing rods lacking a threaded end or the like comprises - a sleeve (11) with a cylindrical hollow body into which is introduced axially the end of the reinforcing rod (7) which has no connecting element; - a coaxial threaded portion (8) on the end of the sleeve (11); - the outer material of the sleeve (11) having undergone deformation by necking-in in the area of the end of the reinforcing rod so that - the material of the ribs (10) on the reinforcing rod also deforms in order connect the reinforcing rod and the sleeve. This deformation may be produced by a piston (21) and die (23) of a jack screwed on to thread (8). After removal of the jack, the further reinforcing rod is attached via thread (8). <IMAGE>

Description

The invention relates to a device for establishment of this mechanical connection. The invention also relates to a bonding method concrete rod mechanics.

It will find its application in particular in the field of building construction using concrete such as buildings in a city or works port or road.

In these fields of application, it is known to use mechanical connections to link the circles to concrete to ensure the continuous transmission of a tensile force.

The mechanical link established according to the invention may be used on construction sites in order to link parts that have been prepared industrial workshop with other concrete bars available on site.

These circles that are used on the site may have a straight end or be shaped like a stock and the round in a known manner on its surface outer ribs or ribs whose dimensions are quite irregular but which are naturally proportioned relative to the diameter of the circle. All of these are calculated to give the bond some resistance and depending on the work implemented, we may have rounds of large diameter with large ribs or small diameter with smaller ribs.

These ribs are generally arranged on the external surface of the circle for example according to a helicoid whose the pitch will also depend on the diameter of the round used and the resistance sought.

We know from European application EP-A-0.098.099 a connection element in two parts each comprising a threaded end, either male for one, or female for the other.

Each of these parts can be crimped on the end of a concrete ring through a cavity formed on these parts, substantially with a location opposite that of the thread.

The connection can then be established by screwing the two parts by means of their thread.

We also know from German application DE-A-32.20.984 a machine for fixing a connection element on the end of a bar. This connection is made by crimping of the material of the element; the effort of crimping being taken up by the machine through pressing on the connection element.

In some circumstances, we will sometimes need to bond concrete rods embedded in a mass of old building concrete with new rounds to concrete, to carry out a work extension or a modification.

Thus, in many cases, concrete reinforcing bars provisions on the existing structure have not been provided for by construction with mechanical connection such as thread to facilitate the connection or on the contrary presents a thread damaged by corrosion or seawater.

So in many cases the ends of bars embedded in the concrete to be bonded do not have construction of a sufficient mechanical connection. The tips unprepared concrete reinforcing bars are free and free from thread and therefore it is not easy to connect end to end two concrete rods.

Sometimes the lack of thread on the end of a bar rather than being due to the construction of the bar is due to an impossibility use this thread because it is corroded.

The absence of thread could also have as originates a site accident, for example if such a previously threaded bar had been sawn unfortunately.

Any mechanical preparation of the end of the bars requires intervention in a specialized workshop on bar. This operation creates a break in the chain of production of armatures and involves handling considerable. This break in charge is very costly and often involves the transportation of hundreds of tonnes of steel, from the place of mechanical preparation to the place of shaping and / or assembly.

The aim of the present invention is to integrate the fitting operation of the socket in the circuit manufacturing without having to prepare the end of the bar before assembling the reinforcements.

We may still have to work on a construction site connect a series of vertical bars with a slab of concrete such as a floor produced industrially in workshop and which would present at the exit of the concrete a series of horizontal bars, these bars can be straight or but it is their end that is needed on the site bond with vertical concrete rods which will constitute the vertical concrete element.

There is also sometimes on site high concentration of steel when the bars of the floor and the vertical bars are very close together and it is sometimes difficult to access easily with big tools.

It is known today to link such bars by means of a tubular sleeve which is crimped to the hurry. For this, it is necessary to implement bulky outer jaws since the system that puts using an enveloping jaw by external pressure must to be powerful. This size is a disadvantage when the concentration of steel and reinforcing bars is high because, if the two bars are too close together, it is no longer possible to intervene quickly on site.

The pressing elements and the environment of the tools are heavy and bulky, which is why it sufficient space is required between the axes of the concrete bars to be able to crimp them and in practice, fifteen centimeters spacing is required.

The operator's daily output over the site is very modest and it takes four to eight connections per hour for heavy equipment, by example of the order of one hundred and sixty kilograms.

It should also be noted that when the jaws intervened by external pressure to crimp the two bars end to end, it is not possible to check and test if the operation is correctly performed and the operator must be trusted.

The devices and matrices used are very heavy to allow a reaction of the effort on the tools. The significant force implemented on the matrix require the use of a heavy exterior frame and cumbersome because the effort must be transmitted to the frame. We uses pressures of up to two hundred tonnes and is not easy to intervene quickly and effectively with a total security on all crimps.

Known devices which crimp perpendicular to the circles by successive passes act randomly because they don't know exactly how will the round be solicited in a hollow or in a rib. It is therefore necessary to implement sleeves of considerable length, of the order of 200 to 250 millimeters and we cannot guarantee that all crimps will be made in good conditions. The result of crimping depends on the pressure set work by the operator.

Known devices using a perpendicular crimping with a movable jaw and a fixed matrix also lead to an almost offset obligatory of the two circles to be bonded because the two bars are no longer aligned due to the asymmetry and the irregularity of the concrete bars which are used.

The purpose of the present invention is to overcome the aforementioned drawbacks and allow to link a concrete reinforcing bar whose end presents no means of connection such as thread. This lack of threading can be due to corrosion or simply the fact that none mechanical connection was not planned during construction. It is may also have this mechanical link cut on the inadvertent construction.

Another purpose of the mechanical connection of circles to concrete according to the invention is to be able to operate quickly on the site and therefore with light and handy tools.

Another object of the mechanical connection of circles to concrete according to the invention is of power, precisely because of small footprint of the tool, operate on concrete irons in high concentration, that is to say very close together each other.

Another object of the mechanical connection of circles to concrete according to the invention is to be able to be tested in it applying a constraint after binding, for example equal to 90% of the elastic limit.

Another purpose of the device for the establishment of a mechanical connection according to the invention is to allow the creation of tested connections so that all manufactured links will be completely safe in terms of quality of the crimping of the sleeve on the end of the round.

Another advantage of the mechanical round connection according to the invention, by controlling the quality of the crimping, is therefore to be able to greatly reduce the length of the sleeve itself and of course to reach a price cost of mechanical connections in a very reduced since the amount of metal used will be greatly diminished.

Another object of the present invention is to ability to intervene quickly on site to link an item that has been manufactured industrially with rounds concrete protruding with other concrete rods usable on the site.

We could for example prepare all the tiles horizontally at the same time industrially and link them then with vertical bars which will all be adjusted at the same height for example by means of coppicing before the end of the bars.

Another advantage of the device according to the invention is to be very handy and easy to use on construction site.

The device is provided with a possibility of test the work that has just been done to have the proof that the link is functional, which will be naturally very advantageous since previously it was not not possible to have, using a crimp with jaws, quality control of the manufactured link.

Another object of the device according to the invention is to be able to greatly increase the quantities of links processed which could grow to four cents a day instead of forty today. The device can be installed at fixed station to industrialize the preparation of bars.

• une douille avec un corps creux cylindrique dans lequel est introduite l'extrémité du rond,
• un filetage à l'extrémité de la douille ; le corps creux et le filetage étant coaxiaux,

destiné à liaisonner deux ronds bout à bout, est caractérisé par le fait qu'il comprend :

• un corps de vérin à double effet,
• un tube prolongateur taraudé ou fileté s'adaptant sur le filetage de l'extrémité de la douille et fixé au corps du vérin,
• un piston creux du vérin se déplaçant entre le corps et le prolongateur,
• un outil à billes ou à grains entourant la douille et dont le diamètre intérieur est inférieur au diamètre extérieur de la douille avant son façonnage, disposé à l'extrémité du piston susceptible de se déplacer verticalement et possiblement également en rotation pour déformer la matière externe de la douille et forcer les côtes du rond à béton à pénétrer à l'intérieur de la douille, afin de provoquer la liaison et sertir la douille sur l'extrémité du rond.

The device for implementing a mechanical connection on a concrete ring having ribs on its outer surface and the end of which is devoid of connection element, the mechanical connection comprising:

• a socket with a cylindrical hollow body into which the end of the round is introduced,
• a thread at the end of the sleeve; the hollow body and the thread being coaxial,

intended to link two rounds end to end, is characterized by the fact that it comprises:

• a double-acting cylinder body,
• a threaded or threaded extension tube fitting onto the thread of the end of the bushing and fixed to the cylinder body,
• a hollow piston of the jack moving between the body and the extension,
• a ball or grain tool surrounding the sleeve and whose internal diameter is less than the external diameter of the sleeve before its shaping, disposed at the end of the piston capable of moving vertically and possibly also in rotation to deform the external material of the socket and force the ribs of the concrete ring to penetrate inside the socket, in order to cause the connection and crimp the socket on the end of the round.

• provoquer l'écrasement de la douille sur l'extrémité du rond par déplacement vertical et possiblement également circulaire d'un outil, entourant la douille et dont le diamètre intérieur est inférieur au diamètre extérieur de la douille avant son façonnage,
• maintenir la liaison mécanique durant le sertissage par l'intermédiaire du filetage,
• renvoyer sur la douille les efforts induits par l'outil.

The method of fixing a mechanical connection to a concrete ring, in particular usable on site, using the device for the implementation of a connection, by which the end of a concrete ring is covered without element connection by means of a socket and a material for the socket is chosen which is more malleable than the material of the round in order to cause the penetration of the ribs of the round inside the hollow body of the socket, is characterized in that it consists of :

• cause the sleeve to be crushed on the end of the round by vertical and possibly also circular displacement of a tool, surrounding the sleeve and whose internal diameter is less than the external diameter of the sleeve before it is shaped,
• maintain the mechanical connection during crimping via the thread,
• return the forces induced by the tool to the socket.

The present invention will be better understood on reading of the following description, which is given only indicative and which is not intended to limit it. She is accompanied by the accompanying drawings which form part thereof integral.

Figure 1 shows the mechanical connection of concrete rods used on a vertical bar and a horizontal crossbar.

Figure 2 is a view of the device according the invention actuating the mechanical connection of a concrete rod on a round whose end is devoid of element of connection.

Figure 3 is a sectional view of the socket showing the shape obtained after deformation.

FIG. 4 shows a variant of the tool which, instead of shifted grain as shown in the Figure 2, will be ball point.

We refer to Figure 1 which shows a connection mechanics of a concrete reinforcing iron, generally designated by (1). This concrete rod known to those skilled in the art is widely used today on construction sites to strengthen constructions. We will try to link the concrete ring (2) with another round (3) which will be arranged coaxially and end to end with the round (2). The link (1) thus ensures a transmission of tensile force continuously between the circle (2) and the circle (3).

There is shown in Figure 1 a single round (3) but this could for example be part of a floor horizontal (4) but which would include a multitude of circles arranged substantially parallel. Each round (3) can exit the floor (4) in a straight line or on the contrary have a butt-shaped end (5) such that shown in Figure 1.

We can also use the mechanical link of concrete reinforcing bars according to the invention in other devices suitable for certain buildings with male / male sleeves or female / female.

The book also includes a part vertical in which will be integrated a series of rounds (2) arranged in parallel. It is therefore necessary to connect the end (6) of the round (3) with the end (7) of the round (2). It should be noted that this end (7) of the concrete ring is devoid of connection element, i.e. it does not includes no thread or thread because then it would easy for the skilled person to operate a mechanical connection.

We have seen that the absence of threading could come or due to corrosion or sawing unfortunate on the construction site.

The mechanical connection (1), when it has been secured to the end (7) of the round by the method according to the invention can be connected to the round (3) for example by screwing. The system used will be of the union type. (3 pieces) no bar can be turned.

We refer to Figure 2 which shows the circle at concrete (2) with its end (7) devoid of any element of connection and in particular of threading. This concrete rod of appropriate diameter present on its outer surface of the ribs (10) arranged for example in a circular fashion or helical. These ribs may be irregular but facilitate in known manner the maintenance of circles in the concrete when subjected to significant pulls. These ribs have different width and height dimensions and adapted according to the diameter of the circle.

Given the construction method, the diameter of the round is not very regular and these ribs are not not very precisely distributed on the external surface of the round.

The mechanical connection of concrete reinforcing bars includes a socket (11) with a cylindrical hollow body in which introduces the end of the round (7) through the orifice (12).

In one embodiment, the socket (11) has a cylindrical shape over a large part of its height but it still has a chamfered part (13), the end of the sleeve (11) has beyond the chamfer (13) a thread (8) also shown in Figure 1.

The mechanical connections of concrete bars are therefore constituted by the cylindrical sleeve (11) which fits on the unthreaded end (7) of the round (2) and which includes a thread (8). It should be noted that the round (2) and the thread (8) are arranged coaxially along the axis (14) to be able make an end-to-end connection of the circles (2 and 3).

It should be noted that the circles must be very well aligned and coaxial because if the edges are no longer aligned, it may result in offset efforts creating a moment prejudicial to the traction of the circles and to the tests of "permanent elongation" or slip test.

According to the invention, by imposed axial crimping by the threaded rod and the thread of the crimp sleeve as well that by the annular shape of the tool, the process according to the invention more certainly leads to focusing the two bars regardless of the geometry of the concrete reinforcing bar.

The different elements of the mechanical connection are naturally made of metal but chooses for the sleeve (11) a more material malleable as the material constituting the concrete ring (2) and this in order to cause penetration of the ribs (10) to the inside of the socket (11) when a pressure on the external surface of this socket. This penetration can be achieved for example at the end (7) of the round causing a crushing of the socket on the end of the round. This can be achieved by example by vertical and possibly circular displacement a tool generally designated by (23).

The material of the ribs of the concrete rod enters the internal zone of the socket facing the round in order to bond the round and the socket.

FIG. 2 shows the device (15) for the installation of the mechanical connection (1).

This device is provided with an extension tube threaded (16) comprising at one of its ends a thread (17) and a thread (30) which is screwed onto the thread (8) of the link (1).

The thread (17) of the extension is fixed in the end (18) of the body of the hollow cylinder used preferably double acting. The body (19) of this jack defines with the extension (16) a zone (20) in which is likely to move a hollow piston (21). We have secured to the end (22) of this piston a tool (23) which could be of different suitable forms and for example circular, with offset grains, or with balls. These devices can, in some cases, be adjustable according to the diameter of the round to be bonded. We can adjust the crimping by playing on the number of balls and creating possibly a circular movement to achieve a crimping in a helical pattern.

To improve surface contacts and obtain a better connection, one could advantageously use a heating system allowing a temperature rise of 500 to 750 ° C for five to ten seconds. A self system high frequency induction is satisfactory for ensuring localized heating of small rooms. We will be able to obtain rapid heating and a rise in temperature in seconds with small, light equipment low frequency.

Metal cooling after bonding has an important advantage because the thermal stress of the shrinking accentuates the crimping and thus causes a very good support and complete and total solidarity of the round and muff.

Heating, in particular by self induction, gives much reduced crimping forces and allows to use smaller tools.

It should be noted as well that, for a diameter of round of 40, it takes sixty tons of pressure with four balls and that for a round diameter of 40, you need fifteen tonnes of hot pressure for a circular tool (23).

It is by having mastered the link in securely joining the round and the coupler, can then greatly reduce the length of the coupler opposite couplers used for example with crimping perpendicular to the bars.

FIG. 4 shows the detail of this tool (23) fitted with balls. Marbles make deformations (27) on the external part of the sleeve (11). It causes a longitudinal crimp and possibly circular when the tool is lowered vertically with a taken on the outside surface of the socket, which causes controlled penetration and possible adjustment by through the balls. This setting is for example obtained by means of the screws shown diagrammatically in (28).

Ball crimping can be helical if we practiced an inclined and semi-peripheral groove on the outside of the tool crown, a fixed point forcing rotation during pushing, the tool being fixed on a ball bearing, the angle of the groove being fixed in function of the propeller pitch (s) and related to the spacing of the bolts of the concrete ring.

The goal is to significantly increase the length of the footprint and penetrate well into the spaces in the hollow of the concrete ring, while recreating on the parts the bonding function of the concrete reinforcing bar. The external material of the sleeve undergoes a deformation by forming linear impressions or helical.

When lowering the piston in the direction of arrow F, the end of the tool (23) moves vertically from a distance D. The base (24) of the tool (23) comes into contact with a swivel element (25). This element is itself placed on a swivel plate (26) with a washer interleaved neoprene.

The tool (23) is applied first on the plane (13) then over the entire outer periphery of the socket (11) by a significant pressure communicated by the piston. It is this pressure and the simultaneous deformation of the periphery of the socket, as shown in the figure 3, which cause the connection of the end (7) of the round to concrete with the socket. The tool performs on the external part of the streak socket (27) in sufficient number of preferably regularly distributed over the entire periphery. The number of streaks will naturally depend on the diameter of the round to bind.

The tool during its vertical displacement and possibly circular over distance D will make streaks on the outer periphery of the sleeve and by pressure, will also cause penetration of the ribs (10) of the round to concrete at its end (7). This penetration will naturally made possible by the choice of material constituting the socket (it) which will be more malleable than the material of the circle in (7).

We can thus link the socket with the end of the concrete ring and crimp them. The material of ribs of the round at its end (7) will be housed in the internal part of the socket to cause this connection.

Referring to Figure 2, we see that the device (15) is operated by the piston (21) when sends the oil under pressure. The body socket (1) with the extension (16) is fixed to the cylinder body (8). he a reaction occurs on the hollow piston which descends on the distance D and causes crimping. The drawings (10) on the outer surface of the round penetrate into the material in the inner area of the socket which is more malleable.

At the end of the operation, the face (24) of the tool comes pressing on the swivel element and testing at the value preset for example 99% of the elastic limit of the round to concrete. This test will be considered good if, during the traction exerted, no recorded slip is observed by a drop in the oil pressure read on the pressure gauge of the cylinder.

If the crimping was not carried out in good application conditions, the connection will come off during the test, and it is better that it is at this time there to avoid further inconvenience on the site. It will either have to be redone or replaced.

We see that the device for the establishment of the mechanical connection that has been described is very compact and that it acts vertically on the circle. So we can use it easily in areas where space is limited or if there is a large concentration of reinforcing bars.

It should be noted that we return to the socket (1) and the round (3) the forces induced by the tool (23). We uses the reaction of the part. The force induced by the jack is returned by the part. This effort contained in the play is not dispersed and there is no need for a frame press release to amortize it. The effort dispersed by the cylinder is returned and fully taken up by the part. It is the inertia of the parts which completely tolerates the force of the jack, something that was not possible with the devices because the play did not play this role of reaction during crimping. The socket and the end of the round play a functional reaction role during the operation and you can work in the air without significant tools or support.

The value of the distance D over which crimping will naturally depend on the density ribs and protrusions on the round as well as diameter of the round and the operating mode, cold, hot, longitudinal or helical.

The present invention may also apply to products other than concrete bars and by example of smooth crimp bars, the end being previously "scratched" by mechanical means or by compression of an imprint.

For the final test, there is the device ball joint support in case of bars protruding from the concrete, for the test on free bars the blocking system on the bar is with self-clamping jaws of the type of machines traction.

Claims (6)

1. Device for implementing a mechanical connection of a concrete reinforcing rod including ribs on its outer surface and the end of which is without any connecting element, the mechanical connection including:

   a bushing (11) with a cylindrical hollow body into which is inserted the end of the reinforcing rod,

   an external thread (8) at the end of the bushing, the hollow body and the external thread being coaxial,

      aimed at connecting end to end two reinforcing rods, characterized in that it comprises:

   a double-action jack body (19),

   an internally or externally threaded extension tube (16) fitting on the external thread of the bushing and fixed to the jack body,

   a hollow piston (21) of the jack moving between the body (19) and the extension tube (16),

   a ball or grain tool (23) surrounding the bushing (11), the inner diameter of which is smaller than the outer diameter of the bushing (11) prior to the shaping of same, arranged at the end of the piston (21), capable of moving vertically and possibly also rotationally in order to distort the outer material of the bushing (11) and to cause the ribs (10) of the concrete reinforcing rod to penetrate into the bushing (11) to bring about the connection and to crimp the bushing (11) onto the end of the reinforcing rod.
2. Device for placing a mechanical connection according to claim 1, characterized in that it includes a hinged member (25) against which abuts the periphery of the tool in the final descending phase of the jack, in order to test the connection.
3. Device for placing a mechanical connection according to claim 1, characterized in that a heating is carried out by means of a high-frequency self-induction at the end of the reinforcing rod.
4. Process for securing a mechanical connection to a concrete reinforcing rod, viz. usable on a building site, implementing the device for implementing the mechanical connection according to claim 1, in which the end of a concrete reinforcing rod without connecting member is recovered by means of a bushing and a material is chosen for the bushing which is more malleable than the material of the reinforcing rod, in order to cause the ribs of the reinforcing rod to penetrate into the hollow body of the bushing, characterized in that it consists in:

   causing the bushing to crush on the end of the reinforcing rod through vertically and possibly also circularly moving a tool, surrounding the bushing, the inner diameter of which is smaller than the outer diameter of the bushing prior to the shaping of same,

   maintaining the mechanical connection during the crimping through the external thread (8) of the end of the bushing,

   imparting onto the bushing the efforts induced by the tool.
5. Process for securing a mechanical connection for concrete reinforcing rods, viz. usable on a building site, according to claim 4, characterized in that after carrying out the connection, a test is made e.g. at a predetermined value of the elastic limit of the concrete reinforcing rod.
6. Process for securing a mechanical connection for concrete reinforcing rods according to claim 4, characterized in that in order to improve the contact surfaces and to achieve a better connection, the end of the reinforcing rod is heated at a temperature of 500 to 750°C for five to ten seconds, and cooled in order to cause the whole to shrink and to enhance the crimping.

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