FR2689156A1 - Process for producing a mechanical connection of reinforcing bars, connection obtained by the method, concrete reinforcing bar allowing the implementation of said method, and installation for preparing concrete reinforcing bars. - Google Patents

Abstract

The invention relates to a method for making a mechanical concrete bar joint and to such a mechanical joint, and to a concrete bar permitting the implementation of the method, and to an installation for preparing concrete bars. It will be used in the concrete construction sector. The method involves joining at least one concrete bar (1) to another concrete bar (2), or to an anchoring point, by way of a tapped joining sleeve (3), the said concrete bar having a nominal cross-section PHI , and at least one reinforced end (4), turned back and threaded, such that the thread root diameter d2 is equal to or greater than the nominal cross-section PHI of the bar. According to the invention, the reinforced end (4) is obtained by a double upsetting, a first axial one permitting an increase in the diameter of the concrete bar, and a second radial one during the threading by means of a rolling technique.

Description

The invention relates to a method for producing a connection

  mechanical concrete rounding, to such a bond obtained by the method, a concrete ring allowing the implementation of the said method, and to an installation for the preparation of concrete reinforcing bars It will find particular application in the field of the construction of concrete elements, buildings, or buildings. In this field, it is common to use mechanical links to bind concrete reinforcing bars in order to ensure the transmission of the tensile force of

continuous way.

  Nowadays, various solutions are proposed by the manufacturers, and mainly using either a crimp connection or a thread connection. In the case of the connection by crimping, a sleeve is used which is crimped on both ends of the rounds to be bonded This technique avoids having to rotate one of the rounds but however presents high risks of sliding, the crimping, difficult to control In addition, its implementation is often uncomfortable on a building site because it must be possible with tools crimping, where o

the link is to be made.

  Increasingly, the mechanical connection by threading is preferred by the users In such a connection, two reinforcing bars are joined, substantially coaxially, by means of a tapped connection sleeve. This solution is also applicable when it is necessary to bond a concrete ring to an anchorage point. Moreover, in order to improve the quality of the mechanical connection of concrete reinforcing bars by threading, a method of producing such a connection has been developed in which, prior to threading, the ends of the rounds concrete to be bonded, in order to make a reinforced zone with a diameter greater than the nominal section of the round, then the thread is cut on the said reinforced zone such that the diameter at the bottom of the thread is equal to or greater than the nominal section of the round concrete. Such a method is satisfactory in most constructions and requires very machining.

  In fact, the end of the concrete ring, with its

  ribs or ribs is cold repressed in a matrix, then the thread is made on this raw back by cutting. Although the discharge is generally limited to a rate of increase of the diameter of the order of%, it is nevertheless necessary to implement pressures when the discharge of very high value can

  go up to 400 or even 500 bars.

  Moreover, it should be noted that more and more, concrete buildings are subjected to dynamic forces, and in these conditions, mechanical connections

  concrete reinforcing bars are subject to tensile effects

  alternate compression Also, the fragility of such bonds is increased and it is necessary to provide these solicitations for them to resist in terms of insecurity. The object of the present invention is to propose a method for producing mechanical connections of concrete reinforcing bars which provide total safety at the level of the connection and which, for the same dimensioning, support

  dynamic stresses with a pulling effect-

alternate compression.

  One of the aims of the present invention is to propose a method for producing a mechanical connection of a concrete slab which makes it possible to produce, at the end of the concrete slab, a reinforced zone such that the diameter at the bottom of the thread is equal. or greater than the nominal section of the concrete slab, but which requires a cold repression of the lower end, and consequently implements

  lower forces of discharge.

  Another object of the present invention is to provide a method for producing a mechanical connection of round concrete which uses a thread of very good quality with good tolerances which does not detract from the

end resistance.

  In particular, the threading is carried out by rolling, which avoids cutting the fibers of the bar and cause break primers during dynamic forces. Another object of the present invention is to propose a mechanical connection of reinforcing bars as well as a concrete slab allowing the implementation of the method of the invention.

present invention.

  Furthermore, another object of the present invention is to provide a plant for preparing such concrete rounds which is economical, a reasonable investment and reduced size being

  data the forces implemented.

  Other purposes and advantages of this

  invention will appear during the description that will

  to follow which is however given only as an indication and

which is not intended to limit it.

  According to the invention, the method of producing a mechanical connection of round concrete, which will find particular application in the field of concrete construction, by which is bonded at least one concrete ring to another concrete ring or at an anchoring point, via a tapped connection sleeve, said concrete slab having a nominal section b D, at least one reinforced end, pushed back and threaded, such that the diameter at the bottom of the net is equal to or greater than the nominal section O of the round, is characterized in that the reinforced end is made by double delivery, a first axial to increase the diameter of the concrete slab, a second radial during the

  threading by the rolling technique.

  The method of the invention makes it possible to achieve a mechanical connection of a concrete slab to an anchoring point or to a mechanical connection of two concrete slabs

  butt substantially coaxially.

  Furthermore, the reinforcing bar allowing the implementation of the method of the invention is characterized in that at least one of its ends carries a double discharge such that the diameter at the bottom of the net is

  greater than or equal to the nominal section of the concrete slab.

  The installation for preparing concrete round according to the invention is characterized by the fact that it has: a) means for immobilizing the concrete slab to be prepared, b) means for axially discharging axially cold l end of the concrete slab, c) means for crimping the span to be discharged and / or threaded, d) means for rolling threading of said end, said means b), c), d), being movable to be placed coaxially in the axis of the concrete block blocked in

the means a).

  The present invention will be better understood in

  reading of the following description accompanied by the drawings

which form an integral part of it.

  Figure 1 shows a mechanical connection of round concrete produced by the method of the present invention. FIGS. 2 a to 2 d show the different steps of the method of producing the mechanical connection of the round concrete according to the invention, and more specifically the work of the end of the concrete ring used in

the process.

  Figure 3 shows an enlarged sectional view showing the dimensional characteristics of

  the end of the concrete bar of Figure 2 d.

  FIG. 4 schematically shows the arrangement of the various means constituting the installation of

  preparation of round concrete according to the present invention.

  The invention relates to a method for producing a mechanical connection of round concrete, a connection thus obtained and a concrete ring allowing the implementation of said method and a plant for the preparation of

such rounds.

  It will notably find its application in the

  field of concrete construction.

  FIG. 1 shows an exemplary embodiment of a mechanical connection making it possible to ensure the connection of two reinforcing bars 1 and 2, end to end, substantially coaxially. Furthermore, this connection uses a threaded sleeve 3 of connection, suitable for receiving on one side respectively the threaded end 4 of the first concrete block 1, and on the other side the end 5 of the second

round concrete 2.

  Each of concrete reinforcing bars is determined by calculation and then chosen from a standardized or regulated range. The characteristic of a concrete slab lies essentially in the imposition of weight and section.

  these being laminated in view of these imperatives.

  In a general manner, the concrete ring has on its outer face ribs or ribs 6 which create protuberances allowing immobilization in translation

  round in the concrete when it is embedded in it.

  Under these conditions, the round has on the one hand a nominal section characterized by b, which is in a way the section of the core of the round, and a diameter on ribs or ribs marked O, as illustrated.

particularly Figure 2a.

  According to the method of the present invention, each concrete bar to be bonded 1, 2 has at least one reinforced end 4, 5, discharged and threaded, such that the net diameter diameter d 2 is equal to or greater than the nominal section P This is particularly

illustrated in Figures 2d and 3.

  More precisely, according to the method, the reinforced end 4, 5 is made by double delivery, a first axial 7, making it possible to increase the diameter of the concrete slab, and a second radial 8 during felling by means of a

rolling technique.

  The first axial discharge 7 is made prior to the threading, and is forced cold end of the concrete round 1, 2, to be bonded in order to achieve a reinforced area 7 corresponding at least

  substantially to the diameter d 4 flanks of net.

  Then, the second radial discharge 8 is performed by making a thread 9 on said reinforced zone 7 by rolling so that the net diameter d 2 is equal to or greater than the nominal section OD of the round. That being so, in general, the upsets 7, 8 are made over the length of the

  threading 9 of said end 4, 5.

  The different stages of the process are

illustrated in Figures 2a to 2d.

  In FIG. 2 a, a first crimping of the end of the round to be reinforced is shown to rid it of its ribs or ribs and to give this end an acceptable cylindricity. This peeling is indicated by the diameter of the neighbor or very slightly less than On this end 4 thus prepared, the first discharge is carried out at a rate of increase of the diameter of the adjacent end of 15 to 20%. This step brings the diameter to a diameter greater than 3, which is itself greater than O diameter of the round This cold discharge is achieved by performing an axial thrust on the end

according to the arrow 10.

  Then, as shown in FIG. 2c, the raised bearing surface 7 is raised, in particular to calibrate it, to the diameter d 4 which will make it possible to perform the threading

desired by rolling.

  According to the rolling technique, this diameter d 4 corresponds to the diameter of the thread flanks shown in FIG. 3. During the rolling, the metal is then pushed back to form the back of the net d 2 and to push it back.

  to form the outer part of the thread dl.

  Under these conditions, it reaches the end as shown in Figure 2 d in which the latter, after a double axial discharge 7 and radial 8, shows a reinforced end such as the diameter at the bottom of the net

  d 2 equal to or greater than the nominal section O of the circle.

  Moreover, to withstand the tensile test imposed by certain safety standards, the end 4 and / or 5 of the reinforcing bar 1 and / or 2 reinforced by backflow,

is prestressed.

  This prestressing makes it possible to cancel all movements and lengthening of concrete reinforcing bars and in particular their ends during safety tests carried out. It is carried out after the threading,

  mechanically by compressing said threaded end.

  The method which has just been described allows the realization of a mechanical connection of two reinforcing butt rods substantially coaxially. However, this method can be adapted to obtain a mechanical connection.

  from a concrete ring to an anchor point.

  In this case, the sleeve will be adapted to the reception of a single round but will present a configuration

  outer shaped anchor sleeve.

  This being the case, for example, in the case of an HA 20 concrete slab with a nominal cross-section of 20 mm, it is practical to

  on its end a thread M 24 of tolerance 6 g.

  After peeling the end of the round, the axial discharge was conducted to obtain a diameter d 3 of 23 Im. Then, the end thus pushed was rolled to bring the diameter d 4 between

21.803 and 22.003 mm.

  On this calibrated end, the thread M 24 was made at a pitch of 3 by rolling. The external diameter d1 then being between 23.577 and 23.952 mm, and the diameter at the bottom of thread d 2 then corresponding to 20.704 mm is greater than 20 mm. the nominal section of the round

HA 20.

  Similarly, starting from a HA concrete round of 20 mmi, to obtain a diameter M 24 at the pitch of two, taking into account the normalization of the threads, it is necessary to start from a pitch diameter equal to the diameter at the sides of the thread. situated

between 22.493 and 22.603 mm.

  Compared to the previous solution in which the end of the concrete ring was cold-pressed in a single step and then the thread was cut, it should be noted a significant gain because the mass back

  needed is much lower.

  Previously, it was necessary to obtain an external discharge of the order of 27 mm, a mass displacement of the order of 50 g and a length of mm. According to the present invention, the necessary axial displacement causes a displacement of a mass of 18 g or a length of 8 mm. The axial displacement is therefore

  decreased from 50 to 18 g, a ratio decreased by 2.8.

  Moreover, the quality of the threading makes it possible to abandon the tolerance 8 g and to implement

tolerances 5 or 6 g.

  FIG. 4 schematically shows an installation for preparing concrete reinforcing bars to allow

  carrying out the process of the present invention.

  The installation comprises, first of all, a feed zone for the concrete slab to be prepared. In this zone, a vise 10 is provided which will be able to clamp the concrete slab 1 and

move it to the installation.

  Following this zone, there are provided means II for immobilizing the round to be prepared. These means consist, for example, of a vise 11 of great length, in particular lined with a coating of natural rubber or polyurethane type in order to avoid the injuries of the rounds.

concrete.

  The advantage of having a large length of vise makes it possible to have a large surface and a

  relative weakness of compression per square meter.

  The vises 10 and 11 are of the hydraulic type and movable horizontally with respect to the longitudinal axis

22 feeding concrete rings.

  The various arrows in FIG. 4 simulate the operation of the system and in particular the following operation: the vice 10 tightens the concrete ring, the immobilizing vise It opens, the vise 10 moves forward, the vise 11 tightens on the round, the vise 10

  free and retreat to prepare for a new cycle.

  In front of the immobilizing vice 11 are slidably provided, a shear 12, means 13 for axially cold-pressing the end of the rounds, as well as a unit of mechanical stress by compression of

the threaded end of the round.

  This will be possible in particular by providing slides 15 in front of the vise to allow a vertical movement of the three tools 12-14 as suggested in the figures, to be placed coaxially in the axis 22 of the

round blocked in 11.

  Under these conditions, we can work the concrete bar without having to change its position,

  it being blocked once and for all in the vice 11.

  Likewise, the installation will present

  16, 17 for crushing the range to be discharged and / or threaded.

  These means will be provided with vertical and horizontal displacement to be able to bring the crimping tool into

  the longitudinal axis 22 of the concrete slab to work.

  Furthermore, the installation will comprise, in the same spirit, means 18 for making a threading rolling, that is to say that the unit 18 will be able to be moved to be placed coaxially in the axis 22 blocked

in the means 11.

  Finally, the installation will also present a unit 19 for screwing and unscrewing a sleeve allowing the

  implementation of the said constraint in the tool 14.

  The main advantage of the installation of the present invention lies in the fact that all operations are carried out without having to move the rebar or reposition it and thus avoid all the positioning and centering that would be mandatory for

  carry out the different machining steps.

  Thus, it will be possible to realize on the concrete slab, and more precisely on the ends, reinforcement by double delivery, a first axial by means 13 for cold delivery, and a second radial for threading by the rolling tool 18. way of doing it makes it possible to reduce the pressures of cold delivery, to facilitate the cold backflow while working on a machined diameter, to eliminate the hardened surface, that is to say the skin

  concrete slab, and its ribs thanks to the peeling.

  Naturally, other implementations of the present, within the reach of those skilled in the art, could have been considered without departing from the scope of the present application. he

Claims (7)

REVENDI CATIONS   1 Process for producing a mechanical connection of reinforcing bars, which will notably find application in the field of concrete construction, by which at least one concrete slab (1) is bonded to another concrete slab (2) , or at an anchor point, through a threaded connection sleeve (3), said concrete round (1) having a nominal section b, and at least one end (4) reinforced, pushed back and threaded, such that the diameter at the bottom of thread d 2 is equal to or greater than the nominal section O of the round, characterized in that the reinforced end (4) is made by double delivery, a first axial (7) to increase the diameter of the concrete slab, a second radial   (8) when threading by a rolling technique.   2 Process according to claim 1, characterized in that: prior to the threading, the end (4) of the concrete bar to be bonded is cold-pressed in order to produce a reinforced zone of diameter corresponding at least substantially to the flank diameter of net d 4, a filleting (9) is made on said reinforced zone (7) by rolling so that the net diameter d 2 is equal to or greater than said nominal section. P.   3. Method according to claim 1, characterized in that the ups and downs (7, 8) are made over the length of fl ying of said end (4). 4 Process according to claim 1, characterized in that the first discharge (7) is carried out at a rate of increase of the diameter of the nearby end of 15%.   Process according to Claim 1, characterized in that, subsequent to the threading of the said discharged end, it is mechanically constrained by   compression said threaded end.   6 Process according to claim 2, characterized by the fact that: the end of the round end is hoed to remove the outer ribs, it is cold repressed by performing an axial thrust on the end to obtain a diameter close to the diameter to flanks of net d 4, the raised range is raised to calibrate it   and perform the desired threading by rolling.   7 Mechanical connection of a concrete slab to an anchor point, obtained by implementing the method   according to any one of claims 1 to 6.   8 Mechanical connection of butt bar substantially coaxially obtained by the implementation   process according to any one of claims 1 to 6.   9 Concrete bar allowing the implementation of the   process according to one of claims 1 to 6,   characterized in that at least one of its ends (4) carries a double discharge (7, 8) such that the net diameter d 2 is greater than or equal to the nominal section of the concrete pad Q. 10 Installation for the preparation of concrete reinforcing bars for authorizing the implementation of the process according to   any one of claims 1 to 6, characterized by   the fact that it has: a) means (11) for immobilizing the round (1) to be prepared, b) means (13) for cold axially repressing the end (4) of the concrete slab, c) means (16, 17) for meshing the span to be discharged and / or threaded, d) means (18) for rolling threading said end, said means b), c), d) being displaceable to be placed coaxially in the axis (22) of the concrete block blocked   in the immobilizing means (11).