Manufacturing device and method for uniaxial reinforcing bar mesh

Abstract

The present invention relates to an apparatus and method for manufacturing a uniaxial reinforcing bar mesh, particularly a uniaxial reinforcing bar mesh suitable for applications not primarily subject to static loads, in which each reinforcing bar is secured to a respective support strap by wire ties.

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for producing a uniaxial reinforcing mesh, in particular a uniaxial reinforcing mesh suitable for applications not primarily subject to static loads. [Background technology]

[0002] In reinforced concrete structures, the load-bearing capacity is improved by improving the static properties of the concrete members using steel bodies or bars that absorb tensile forces and supplement the compressive strength of the concrete. This is done by bringing steel bodies, deformed bars or round bars individually to the construction site and weaving them together manually, or by welding uniaxial or biaxial reinforcing meshes into place, or by forming them into specially shaped segments. Since uniaxial reinforcing meshes can only absorb tensile forces in one direction, i.e. the longitudinal direction, two uniaxial reinforcing meshes are required for each reinforced concrete member, at an angle of 90°, to absorb the tensile forces and bending moments in each direction. Cold- or hot-formed reinforcing bars usually have a twist-free, almost circular cross section and faces with diagonal ribs, with longitudinal ribs if necessary. Reinforcing bars are often up to 12 m long and up to 40 mm in diameter, so they can weigh several hundred kg.

[0003] For mainly static loads, connections by welding have long been known and proven. Welded uniaxial reinforcing meshes have a particular advantage in that they can be laid particularly quickly at the construction site. Corresponding devices have also been known for some time, for example from EP 0 862 958 or PCT / DE2009 / 000298. The device for the production of uniaxial reinforcing meshes according to EP 0 862 958 comprises a transverse supply of reinforcing bars to a mesh former. Already manufactured reinforcing bars are taken from a supply magazine, reinforcing bars to be produced from them are drawn from coils, straightened and cut to length by a bar former designed as an automatic straightening and cutting machine. The reinforcing bars fed to the mesh former are positioned transversely of the mesh by a transverse positioning device and welded to flexible support strips by an automatic welding machine. The uniaxial reinforcing meshes can be up to 15 m wide and can consist of reinforcing bars of different diameters and lengths. The use of thin steel strips with a constant width allows for good directional stability of the reinforcing bars being unwound. The wide steel strip has good linear stability, and after unwinding, the rebar is placed accurately and stably in the pre-calculated and assumed position.

[0004] However, welded rebar mesh is less suitable for reinforced concrete members and structures subjected to non-static loads, such as those encountered in civil and structural engineering and building construction. Such reinforced concrete members include those used in road and railway bridges subjected to alternating loads from traffic flow, offshore wind turbines subjected to wave action, and structures such as towers, masts and tall buildings subjected to dynamic excitations from wind gusts and vortex shedding. Also, structures subjected to non-static loads include concrete members in industrial plants such as crane runways, forklift ceilings and machine foundations. All such members may experience material fatigue due to the permanent, high frequency and cyclic alternating stresses associated with repeated loading. This type of stress is the main cause of damage to the aforementioned members and structures.

[0005] In welded joints, the fatigue behavior of the material is mainly concentrated locally at the weld seam, so that the fatigue strength of the steel material is significantly reduced due to changes in the microstructure and strong notch effects, and welded joints are considered problematic among experts. For example, known welded rebar meshes and round bars, when used under loads that are not mainly static, cannot achieve the fatigue strength specified in Eurocode 2 due to the notch effect of the weld, and are significantly below the Wohler curve of steel bars. Therefore, single bars are mainly used for structural members subjected to dynamic loads, but single bars must be connected manually at the construction site using thin wires in a laborious and time-consuming manner, and the production of surfaces subjected to dynamic loads is expensive due to the costly manual connection. The use of welded rebar meshes instead would require a significant increase in the amount of steel used, as sufficient material allowance is required.

[0006] From EP 1 856 346 A1, an apparatus for the production of uniaxial reinforcing steel meshes is known. In this apparatus, the reinforcing steel bars are fed in according to the same principle, but instead of being welded onto a number of parallel, flat, flexible steel strips, the reinforcing steel bars are fixed in place at several points in the axial direction of the reinforcing steel bars by being sandwiched between two wires and the wires being twisted together. In this apparatus, the two wires are tightly twisted by a twisting machine to produce a wire strand. The wires of the wire strand are guided so that they surround the reinforcing steel bars being fed in, and the reinforcing steel bars are fixed in the meshes of the wire strand formed. For the permanent parallel arrangement of the reinforcing steel bars, an endless wire strand produced in situ is thus used instead of the endless steel strips mentioned above. Disadvantages of this apparatus and the method include the fact that the bonds between the wire strands and the reinforcing steel bars are not strong enough, which can lead to changes in the position of the reinforcing steel bars in the uniaxial mesh relative to each other, and the extremely low directional stability when the uniaxial mesh is unwound at the construction site.

[0007] DE 44 36 610 A1 discloses a device in which a reinforcing bar is fastened to a strip by means of a wire, one wire connector being arranged above the reinforcing bar and another wire connector being arranged below the strip. A wire is fed from the first wire connector and enters an open deflection groove of a second wire connector, where it is deflected and returned to the funnel-shaped hole of the first wire connector. After a few revolutions of the first connector, the end of the wire is cut off. Summary of the Invention [Means for solving the problem]

[0008] SUMMARY OF THE PRESENT EMBODIMENTS It is therefore an object of the present invention to provide an apparatus for manufacturing a uniaxial reinforcing bar mesh suitable for applications primarily subject to non-static loads, and a method for manufacturing said uniaxial reinforcing bar mesh.

[0009] The apparatus-related objects are achieved by the apparatus described below, and the method-related objects are achieved by the method described below.

[0010] The apparatus of the present invention includes a steel strip conveyor, a rebar conveyor, and a plurality of connecting units, the steel strip conveyor conveying a plurality of support strips so that they are arranged in parallel with a space between them, the rebar conveyor conveying individual rebars onto the plurality of support strips so that they intersect with the plurality of support strips to form intersections between the support strips and the rebars, and it is preferable that the individual rebars are arranged in the longitudinal direction relative to the plurality of support strips, each connecting unit being operatively disposed at each intersection, each connecting unit having a bundling wire conveyor, the bundling wire conveyor feeding bundling wire through a rotating unit, and the rotating unit being movable relative to the support strips and the rebars intersecting therewith. , which is disposed on one side of a plane defined by the support band and the rebar, and further includes a bundling wire guide unit on the opposite side of the plane, which sends out and holds the bundling wire fed by the bundling wire conveyor in a direction opposite to the feeding direction by friction, and the rotating unit twists two bundling wire strands located on one side of the plane and cuts them to a certain length, and the rotating unit and the bundling wire guide unit approach each other and close to each other to form a wire loop, and the support band and the rebar are pressed against each other and connected by the wire loop. Therefore, when using this device, the bundling wire is tightly guided and there is no need to close any gaps that may occur between the rebar and the support band, so that the support band and the rebar are positioned at a precise location, and a precise and durable connection is achieved, which is a great advantage.

[0011] The great advantage is that the rebar is fixed to a wide, flat and flexible support strip, especially a steel strip. The steel strip has good directional stability during unwinding, does not require material allowances or the use of high-grade steel, and is ideally suited for structural members where the main load is not static. The fixing of the rebar to the steel strip is achieved by a wire loop according to the invention. The wire loop is realized by a ring-shaped wire loop that surrounds the support strip and the fed rebar at their intersection and connects them by a pressure fit. Furthermore, the wire bundling according to the invention also allows the use of non-welded materials for the rebar and thus the uniaxial mesh, such as epoxy-coated steel, galvanized material, stainless steel, etc. The uniaxial rebar mesh of the invention therefore has such a variety of wire loops. The number of wire loops per rebar corresponds to the number of intersecting support strips to which the rebar is fixed, so that there are nx wire loops per n support strips of the mesh, where x is a number between 0 and n-2.

[0012] In one embodiment of the invention, the device has a cutting tool, in particular a blade, preferably a fixed blade, in the region of the rotating unit. After the required length of the tie wire has been fed, the rotating unit moves upwards away from the reinforcing bar, where the tie wire is cut by a correspondingly shaped blade and at the same time is bent, due to the further movement of the rotating unit and the resistance of the blade, in a direction approximately opposite to the direction of movement of the rotating unit, in particular up to 180°. The bent free end of the tie wire thus produced advantageously creates a resistance in the rotating unit during rotation that prevents the tie wire from slipping out of the tie wire guide, so that the tie between the support strap and the reinforcing bar is strong and firm.

[0013] Advantageously, the length of wire cut by the device, which binds the support strap and the crossing rebar, is bent by the device from a direction generally perpendicular to the plane to a direction generally parallel to the plane, thereby avoiding the risk of injury from protruding wire ends.A major advantage is that the wire ends of the bent wire loop are in the plane containing the rebar and the support strap in the unwinding direction, thus preventing contact with the user.

[0014] In one configuration of the invention, it is advantageous for the support strap to have guides for the binding wires, in particular openings and / or recesses, which are preferably created in situ by the device. This guide advantageously forms a fixed loop of the binding wire guided around the intersection, so that the binding does not come loose even if the support strap bends or buckles, for example when winding or unwinding the uniaxial reinforcing mesh. The guides may be holes (in particular elongated holes) in the support strap, cuts in the end regions of the support strap, or a combination of both.

[0015] The distance A between the two guides is appropriately selected according to the diameter of each reinforcing bar to be connected. In particular, the distance A is smaller than the diameter of the reinforcing bar to be fixed, which has the great advantage that a strong binding can always be obtained even for reinforcing bars of different diameters. By making the web width match the diameter of the reinforcing bar, twisting of the reinforcing bar can be prevented. The web width can also be made wider than the diameter of the reinforcing bar. In that case, the reinforcing bar will be surrounded, which has a favorable effect on stabilizing the position and also provides a strong binding.

[0016] In one refinement of the invention, the length L of the binding wire 8 required for the connection is adapted depending on the diameter of the respective reinforcing bar to be connected, which not only allows saving in binding wire material but also ensures that the twisted binding wire portion or the free end of the formed wire loop is always as short as possible, i.e. protruding as little as possible.

[0017] The method of the present invention for producing a uniaxial reinforcing bar mesh includes a plurality of support bands arranged in parallel at intervals, and a plurality of reinforcing bars fixed in a direction perpendicular to the plurality of support bands and arranged in parallel at intervals, the method comprising the steps of: a) feeding rebars perpendicular to the longitudinal axis of spaced parallel support strips, thereby forming multiple intersections between each strip and each rebar; b) pressing the reinforcing bar against the support band to bring them into close contact with each other; c) providing a tie wire in the area of ​​the intersection to encircle the steel strip and the rebar, thereby forming two tie wire strands on one side; and d) cutting the bundling wire to a fixed length and twisting the two bundling wire strands together to form a twisted portion. Includes.

[0018] In one configuration of the method of the invention, step d) is followed by a step e) of bending the torsion section in or towards a plane defined by the support strap and the rebar.

[0019] In the present invention, the step of pressing the reinforcing bar against the support strap is carried out before, during or after step c) and / or step d).

[0020] In one refinement of the method of the invention, step d) comprises bending a second free end of said cable tie cut to length.

[0021] In one configuration of the method, there is a step f) of introducing a guide into the orthotic. [Brief description of the drawings]

[0022] The invention will now be explained in more detail with reference to figures of exemplary embodiments, in which identical components are provided with the same reference numerals. [Figure 1] FIG. 2 is a schematic diagram of a wire loop. [Diagram 2] FIG. 1 is a schematic cross-sectional view showing an embodiment of the device of the present invention in a first state. [Diagram 3] FIG. 2 is a schematic cross-sectional view showing an embodiment of the device of the present invention in a second state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] FIG. 1 shows a wire tie loop according to the invention around the intersection 5 of a support strap 2 (here a flat flexible steel strap) and a reinforcing bar 4 (here a rod-shaped reinforcing bar). In the support strap 2, elongated holes 17 can be seen, the shortest end-to-end distance A between the elongated holes 17 being smaller than the diameter D of the reinforcing bar 4. Here, the two elongated holes 17 are an embodiment of the inventive guide 14 for the wire tie 8 and are in the form of an opening 15. When the method according to the invention is carried out, the wire tie 8 is guided through the two elongated holes 17 and the two wire tie strands 11 are twisted together to form a twisted part 18. In the present invention, this twisted part 18 is bent, in particular approximately parallel to the plane formed by the support strap 2 and the reinforcing bar 4, so as to prevent it from protruding from the concrete later and thus also from causing injury to the user. It is to be understood that the plane does not mean a strictly mathematical two-dimensional plane, but rather a three-dimensional plane formed by the support strap 2 and the reinforcing bar 4. The width of the support strap 2 of the uniaxial reinforcing mesh is selected so that the mesh can be unrolled with safe linear stability.

[0024] In the present invention, the rebars 4 are selected from those with a diameter of 6 mm to 40 mm, and the distance between the rebars 4 arranged in parallel that constitute the uniaxial rebar mesh can be freely selected according to the requirements of the application of the uniaxial rebar mesh. This selection is made by computer-controlled optimized planning regarding length, position, distance, diameter, material, etc. Preferably, a minimum distance is maintained between two adjacent rebars 4 to ensure transportation safety.

[0025] The end-to-end distance A of the webs of the support strap 2 between the elongated holes 17 is adjusted to the diameter D of the reinforcing bar to be bound. In particular, the end-to-end distance is smaller than or equal to the width of the reinforcing bar. This ensures that the binding will not loosen even if the support strap 2 is bent or twisted, especially when it is wound during production. By appropriately adjusting the dimensions of the end-to-end distance A, a strong binding is always obtained, even if the diameter D of the reinforcing bar 4 is different. It also prevents twisting along the longitudinal axis of the reinforcing bar 4. In the present invention, this distance A can also be selected to be larger than the diameter D of the reinforcing bar. In that case, the reinforcing bar 4 is surrounded, which has a positive effect on the stabilization of the position and also provides a strong binding.

[0026] FIG. 2 shows an embodiment of the invention in a first operating state. In this operating state, the reinforcing bars 4 are already fed onto a number of support strips 2 and, if necessary, are arranged axially relative to the support strips. The support strip conveyor 1 and the reinforcing bar conveyor 3 are each shown in a simplified schematic, with the intersection 5 located below the reinforcing bar 4 in the figure, and the rounded bundling wire guide unit 10 is arranged below the intersection 5 and preferably partially surrounds the support strips 2 and the reinforcing bar 4. The bundling wire conveyor unit 7 is shown in a schematic manner. The bundling wire conveyor unit feeds the bundling wire 8 through the rotating unit 9 in the direction of the intersection 5. The connection unit 6 of the invention is composed of the components bundling wire conveyor 7, the rotating unit 9 and the bundling wire guide unit 10. The rotating unit 9 has a U-shaped body through which the bundling wire 8 is guided.

[0027] In this embodiment, the support strip 2 is guided by a punching unit 19, which is shown diagrammatically, by means of which guides 14 in the form of elongated holes 17 are produced in situ in the support strip 2. In the present invention, the guides 14 can be, for example, triangular or dovetail-shaped recesses in the end regions of the support strip 2, in particular recesses which are offset from one another obliquely relative to the longitudinal axis of the support strip 2, but also openings 15 of a shape different from the elongated holes. In the present invention, a support strip 2 can also be used which is already provided with guides 14 during production.

[0028] The operating state shown is the state before connection. To form the wire loop, the rotating unit 9 and the bundling wire guide unit 10 are brought close to each other, so that the bundling wire 8 is fed tightly into the wire guide unit 10 below the intersection 5 of the support strap 2 and the rebar 4, and then fed out in the opposite direction to the feeding direction. The specific projection length is selected depending on the diameter D of the rebar 4 to be fixed after feeding.

[0029] FIG. 3 shows a second operating state in which the connection is made by creating a tightly tightened wire loop. The rotating unit 9 is raised above the rod-shaped cross section. Here, the cable tie is cut by a blade 13 as a cutting tool 12 arranged in front of the rotating unit 9, as seen in the conveying direction of the cable tie 8. The second free end of the wire thus formed, preferably by the structure of the blade 13, is simultaneously bent by the blade, preferably towards the reinforcing bar 2. During the rotation of the rotating unit 9, the twisting shortens the length of the protruding wire, which would otherwise be expected to cause the wire to slip out, but this bent end creates a resistance that prevents the wire from slipping out. The tie is thus strong and firm. By rotating against this resistance, the two cable tie strands 11 are twisted together, forming a twisted part 18. Finally, this rotation causes the bent end to move out of the rotating unit 9. The tight hold is released and the reinforcing bar is free. In the present invention, the rebar and support straps are pressed further together during the tying process, so that they are held in a tighter position.

[0030] As the rebar is transported further, the twisted portion 18 is further twisted to prevent it from protruding too much. Without the twist, the tie may protrude above the concrete and cause injury. [Explanation of symbols]

[0031] 1 Support belt conveyor 2 Support belt 3 Rebar conveyor 4. Steel Bars 5 intersection 6 Connecting Units 7. Binding Wire Conveyor 8. Wire ties 9 Rotating Unit 10 Wire tie guide unit 11 Wire tie strands 12 Cutting tools 13 Blades 14 Guide 15 Opening 16 17 Slot 18 Twisted section 19 Punching unit 20 Passage for binding wire A End Distance D diameter

Claims

1. An apparatus for manufacturing a uniaxial reinforcing bar mesh, The apparatus comprises a steel strip conveyor (1), a rebar conveyor (3), and a number of connecting units (6), The steel strip conveyor (1) transports a plurality of support strips (2) so that they are arranged in parallel at intervals; The rebar conveyor (3) transports each rebar (4) onto the plurality of support belts (2) so as to intersect with the plurality of support belts (2), forming intersections (5) between the support belts (2) and the rebars (4), and the individual rebars (4) are arranged along the longitudinal axis of the plurality of support belts (2); Each of the connection units (6) is operably disposed at each of the intersections (5), each of the connection units (6) having a bundling wire conveyor (7) for feeding the bundling wire (8) through the rotating unit (9); the rotating unit (9) is movable relative to the support band (2) and the reinforcing bar (4) intersecting the support band (2) and is disposed on one side of a plane defined by the support band (2) and the reinforcing bar (4); The rotating unit (9) includes a cutting tool (12), the connecting unit (6) further includes a bundling wire guide unit (10) on the opposite side of the plane, the bundling wire guide unit (10) sends out the bundling wire (8) fed by the bundling wire conveyor (7) in a direction opposite to the feeding direction and holds it by friction; The rotating unit (9) twists two bundling wire strands (11) located on one side of the plane together and cuts them to a certain length; a length of wire cut by the device, which binds the support strap (2) and the rebar (4) crossing it, is bent by the device from a direction generally perpendicular to the plane to a direction generally parallel to the plane; When the rotating unit (9) and the bundling wire guide unit (10) approach each other and enter a closed state, a wire loop () is formed, and the support belt (2) and the reinforcing bar (4) are pressed against each other and connected by the wire loop. The device has a punching unit (19) for producing guides (14) in the support band (2) in situ, The device, wherein the guide (14) is an opening (15) and / or a recess.

2. The device described in claim 1, wherein the cutting tool (12) is a blade (13).

3. 3. The device according to claim 1 or 2, wherein the opening (15) is formed as an elongated hole (17).

4. 4. The device according to claim 1, wherein the end-to-end distance (A) between the two guides (14) is selected depending on the diameter of each reinforcing bar (4) to be connected, said end-to-end distance (A) being smaller than the diameter (D) of the reinforcing bar (4) to be fixed.

5. 5. The device according to claim 1, wherein the length (L) of the tie wire (8) required for connection varies depending on the diameter of each reinforcing bar (4) to be connected.

6. A method for manufacturing a uniaxial reinforcing bar mesh, the uniaxial reinforcing bar mesh being a uniaxial reinforcing bar mesh in which a plurality of support bands are arranged in parallel with a space therebetween, and a plurality of reinforcing bars fixed in a direction perpendicular to the plurality of support bands are arranged in parallel with a space therebetween; a) feeding rebars perpendicular to the longitudinal axis of spaced parallel support strips, thereby forming multiple intersections between each strip and each rebar; b) pressing the reinforcing bar against the support band to bring them into close contact with each other; c) providing a tie wire in the area of ​​the intersection to encircle the steel strip and the rebar, thereby forming two tie wire strands on one side; and d) cutting the bundling wire to a certain length and twisting the two bundling wire strands together to form a twisted portion. The method includes:

7. 7. The method of claim 6, wherein step d) is followed by step e) of bending the torsion section in or towards a plane defined by the support strap and the rebar.

8. 8. The method according to claim 6 or 7, wherein step b) of pressing the rebar against the support straps is carried out before, during or after step c), or before, during or after step d).

9. 9. The method of claim 6, wherein step d) comprises bending a second free end of the cable tie wire that has been cut to length.

10. A method according to any one of claims 7 to 9, wherein step f) of introducing a guide into the support band is carried out before or after step a).

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