Method for manufacturing truss reinforcement bars and shaping jig

Abstract

This invention provides a method for manufacturing truss reinforcement bars suitable for construction of structures using 3D printers for construction. [Solution] The truss reinforcement 10 has a pair of rod-shaped main reinforcements 12 and a zigzag-shaped lattice reinforcement 14 that engages with the pair of main reinforcements 12 in a spiral manner. The manufacturing method of the truss reinforcement 10 includes a lattice reinforcement forming step in which the lattice reinforcement material 14A is formed into a zigzag shape, and the lattice reinforcement material 14A is temporarily deformed excessively with a forming jig in the direction opposite to the direction in which the lattice reinforcement material 14A returns to its original shape, thereby releasing the lattice reinforcement material 14A from the forming jig and eliminating the excess deformation.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing truss bars suitable for the construction of structures using a construction 3D printer and a molding jig used therefor.

Background Art

[0002] In recent years, construction of structures using a construction 3D printer has attracted attention. By supplying and laminating mortar in layers from the nozzle of the 3D printer, structures of various shapes can be formed without using a formwork, which is excellent in terms of workability, labor saving, and design freedom. When sufficient strength cannot be obtained only with mortar, steel bars are used in the same manner as in general concrete structures. For example, when forming a truss structure wall excellent in structural strength and heat insulation with a 3D printer, it is conceivable to use truss bars having a shape along the truss structure wall. The truss bar has a configuration in which zigzag lattice bars (diagonal members) are installed between a pair of main bars (chords) arranged in parallel, and the main bars and the lattice bars are joined by spot welding or arc welding. In the construction of structures using a construction 3D printer, it is assumed that a planar truss bar is laid on the mortar layer during the printing process. Note that the application target of the planar truss bar is not limited to the truss structure wall, and it is expected to use a planar truss bar that is easy to manufacture and excellent in strength when forming other shaped structures with a 3D printer.

[0003] On the other hand, in conventional planar truss reinforcement, the strength of the welds is lower compared to the strength of the main reinforcement and lattice reinforcement, and the overall strength of the truss reinforcement may not be obtained as expected from the strength of the main reinforcement and lattice reinforcement. When forming structures with a 3D printer, it is also envisioned that relatively small diameter main reinforcement and lattice reinforcement may be used. In such cases, the strength of the welds between the main reinforcement and lattice reinforcement tends to be low, and sufficient reinforcement effect may not be obtained. In contrast to this, truss reinforcement is known in which the lattice reinforcement engages with a pair of main reinforcement so as to be spirally wrapped around them (see, for example, Patent Documents 1 and 2). In this configuration, the lattice reinforcement engages with the main reinforcement so as to fold back in a U shape at the bending portion, so when a tensile force is applied to the lattice reinforcement, the lattice reinforcement is reliably supported by the main reinforcement regardless of the strength of the welds between the lattice reinforcement and the main reinforcement. Furthermore, when compressive forces are applied to the lattice reinforcement, the mortar in which the truss reinforcement is embedded bears the compressive force, and the lattice reinforcement is not required to bear the compressive force in the design. It is expected that truss reinforcement of this configuration will also be used in the fabrication of structures using construction 3D printers. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-279770 [Patent Document 2] Japanese Patent Application Publication No. 11-57918 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, when lattice reinforcement material is spirally wrapped around a pair of main reinforcement bars to form a zigzag shape, it may not be possible to obtain the desired planar lattice reinforcement. For example, the lattice reinforcement may twist as a whole in the opposite direction to the direction in which it was wrapped due to the return deformation. Also, the parts between the bent sections of the lattice reinforcement may not be straight but curve outwards, resulting in the lattice reinforcement as a whole appearing to bulge in the thickness direction. The twisting and bulging described above in the processing of lattice reinforcement are caused by the material properties of the steel used in the lattice reinforcement. Specifically, the bending moment at the point where the reinforcement is wrapped exceeds the yield bending moment of the wire, resulting in plastic bending. However, when the bending moment is removed, springback causes a return deformation, resulting in twisting. Furthermore, the small-diameter steel wire used in lattice reinforcement does not exhibit a clear yield point, and even after apparent yielding, the stress gradually increases with increasing strain. As a result, plastic bending occurs near the point where the reinforcement is wrapped, leaving a gentle curve and bulge before and after the point where it is wrapped. It should be noted that even truss reinforcing bars with twisted or bulging shapes in the thickness direction may not pose a problem in general concrete pouring. On the other hand, when mortar is supplied in layers from the nozzle of a 3D printer and stacked, if truss reinforcing bars with twisted or bulging shapes in the thickness direction are laid on top of the mortar layer, the truss reinforcing bars may not adhere well to the mortar layer, and sufficient reinforcement effect may not be obtained. This invention has been made in view of the above problems, and aims to provide a method for manufacturing truss reinforcing bars suitable for the construction of structures using a construction 3D printer. [Means for solving the problem]

[0006] The present invention provides a method for manufacturing a truss reinforcement having a pair of rod-shaped main reinforcements and a zigzag-shaped lattice reinforcement that engages with the pair of main reinforcements in a spiral manner. The method includes a lattice reinforcement forming step in which the lattice reinforcement material is formed into a zigzag shape, and the lattice reinforcement material is temporarily deformed excessively using a forming jig in the direction opposite to the direction in which the lattice reinforcement material returns to its original shape. The lattice reinforcement material is then released from the forming jig, causing the lattice reinforcement material to return to its original shape and the excess deformation to be eliminated. This method solves the above problem.

[0007] In this method of manufacturing truss reinforcement, the lattice reinforcement material is temporarily deformed in the opposite direction to the direction of its return deformation using a forming jig. Then, by releasing the lattice reinforcement material from the forming jig, the lattice reinforcement material deforms in a way that eliminates the excess deformation. As a result, a planar lattice reinforcement is obtained in which the return deformation of the lattice reinforcement material is eliminated or suppressed.

[0008] The lattice rebar forming process includes a lattice rebar wrapping and forming process in which lattice rebar material is wrapped spirally around a wrapping and forming jig to form a zigzag shape, wherein the wrapping and forming jig has a twisted shape in the direction in which the lattice rebar material is wrapped, and the lattice rebar material may be configured to twist and deform to conform to the twisted shape when wrapped around the wrapping and forming jig, and to deform back in a direction that eliminates the twisted deformation when removed from the wrapping and forming jig.

[0009] When the lattice reinforcing bar material is wrapped around the wrapping jig, the lattice reinforcing bar material temporarily twists and deforms in the same direction as the wrapping direction, following the twisted shape of the wrapping jig. Subsequently, when the lattice reinforcing bar material is removed from the wrapping jig, the lattice reinforcing bar material deforms back in the opposite direction to the wrapping direction. As a result, a planar lattice reinforcing bar is obtained in which the twisting deformation is eliminated or suppressed.

[0010] The wrapping formwork jig may have a configuration comprising a pair of rod-shaped main members corresponding to a pair of main reinforcing bars, and a plurality of connecting members that connect the pair of main members. With such a configuration, a wrapping formwork jig with a twisted shape in the direction in which the lattice reinforcing bar material is wrapped can be easily realized. For example, a linear ladder-shaped intermediate body having a pair of rod-shaped main members and a plurality of connecting members that connect the pair of main members can be first fabricated, and the above-mentioned wrapping formwork jig can be obtained by twisting and deforming this intermediate body.

[0011] Furthermore, the lattice rebar forming process may include a lattice rebar pressure forming process in which the lattice rebar material, formed into a zigzag shape, is sandwiched between pressure forming jigs on both sides in the thickness direction and pressurized. The pressure forming jig has a shape in which the part corresponding to the part between the bent portions of the lattice rebar material protrudes in the thickness direction more than the part corresponding to the bent portions, so that the part between the bent portions of the lattice rebar material is pressed in the thickness direction more than the part between the bent portions of the jig. The lattice rebar material may also be configured to deform back in a direction that eliminates the deformation in which the part between the bent portions of the lattice rebar material has been pressed in the thickness direction when the pressure forming jig separates from the lattice rebar material.

[0012] When the pressure forming jig presses the lattice reinforcing bar material in the thickness direction, pushing it further into the areas between the bent sections than into the bent sections, the areas between the bent sections of the lattice reinforcing bar material are temporarily deformed into a shape that is pushed further in the thickness direction than into the bent sections. Subsequently, when the pressure forming jig is removed from the lattice reinforcing bar material, the lattice reinforcing bar material deforms back in a direction that eliminates the deformation in the thickness direction of the areas between the bent sections. As a result, a planar lattice reinforcing bar is obtained in which the bulging shape in the thickness direction is eliminated or suppressed.

[0013] Furthermore, the lattice rebar forming process includes a lattice rebar wrapping and forming process in which the lattice rebar material is wrapped spirally around a wrapping and forming jig to form a zigzag shape. The wrapping and forming jig has a shape in which the thickness of the part between the ends is thinner than the thickness of the ends on both sides in the width direction. In the lattice rebar pressure forming process, the lattice rebar material wrapped around the wrapping and forming jig may be pressed from both sides in the thickness direction by a pressure forming jig. With a wrapping and forming jig configured in this way, the lattice rebar wrapping and forming process and the lattice rebar pressure forming process can be performed continuously without removing the lattice rebar material from the wrapping and forming jig, contributing to improved productivity.

[0014] Furthermore, the present invention solves the above problem by providing a forming jig used in the process of forming lattice bars for a truss reinforcement having a pair of rod-shaped main reinforcing bars and zigzag-shaped lattice reinforcing bars that engage with the pair of main reinforcing bars in a spiral manner, wherein the forming jig is configured to temporarily deform the lattice reinforcing bar material in the opposite direction to the direction in which the zigzag-shaped lattice reinforcing bar material deforms back, and then release the lattice reinforcing bar material so that the lattice reinforcing bar material deforms back and the excess deformation is eliminated.

[0015] The forming jig is a winding forming jig in which the lattice reinforcing bar material is wound in a spiral shape, and the jig may be configured such that the lattice reinforcing bar material is twisted in the direction in which it is wound, and when the lattice reinforcing bar material is wound, it twists and deforms to conform to the twisted shape, and when the lattice reinforcing bar material is removed, it deforms back in the direction in which the twisted deformation is relieved.

[0016] Furthermore, the winding forming jig may have a configuration comprising a pair of rod-shaped main members corresponding to a pair of main reinforcing bars, and a plurality of connecting members that connect the pair of main members.

[0017] Furthermore, the jig for wrapping and forming may have a shape in which the thickness of the portion between the ends is thinner than the thickness of the end in the width direction corresponding to the pair of main reinforcing bars.

[0018] Further, the forming jig may be a pressure forming jig that presses a lattice reinforcing bar material formed in a zigzag shape from both sides in the thickness direction, and in a portion between the bent portions of the lattice reinforcing bar material, the lattice reinforcing bar material is pushed into the thickness direction more than at the bent portions so as to be pressed. A portion corresponding to the portion between the bent portions protrudes in the thickness direction more than the portion corresponding to the bent portions, and the lattice reinforcing bar material is configured to return and deform in a direction in which the deformation in which the portion between the bent portions of the lattice reinforcing bar material is pushed into the thickness direction is eliminated by separating from the lattice reinforcing bar material.

Effect of the Invention

[0019] According to the present invention, a truss reinforcing bar suitable for construction of a structure using a construction 3D printer can be manufactured.

Brief Description of the Drawings

[0020] [Figure 1] Perspective view showing a method for manufacturing a truss reinforcing bar according to a first embodiment of the present invention [Figure 2] Flowchart showing the manufacturing process of the truss reinforcing bar [Figure 3] Perspective view showing an enlarged part of a jig for winding and forming [Figure 4] Front view schematically showing a pressure forming jig and a lattice reinforcing bar pressure forming process according to a second embodiment of the present invention [Figure 5] Flowchart showing the manufacturing process of the second embodiment [Figure 6] Perspective view schematically showing a holder according to a third embodiment of the present invention [Figure 7] Front view schematically showing a lattice reinforcing bar pressure forming process according to a fourth embodiment of the present invention [Figure 8] Flowchart showing the manufacturing process of the fourth embodiment [Figure 9] Perspective view schematically showing a jig for winding and forming according to a fifth embodiment of the present invention [Figure 10] Perspective view schematically showing a jig for winding and forming according to a sixth embodiment of the present invention [Figure 11]Perspective view showing truss reinforcement according to the seventh embodiment of the present invention [Figure 12] A flowchart showing the manufacturing process of the truss reinforcement bars. [Figure 13] Perspective view showing truss reinforcement according to the eighth embodiment of the present invention [Modes for carrying out the invention]

[0021] A first embodiment of the present invention relates to a method for manufacturing a truss reinforcement bar 10 shown in Figure 1. The truss reinforcement bar 10 has a pair of rod-shaped main reinforcement bars 12 and a zigzag-shaped lattice reinforcement bar 14 that engages with the pair of main reinforcement bars 12 in a spiral manner. The method for manufacturing the truss reinforcement bar 10 includes a lattice reinforcement bar forming step in which the lattice reinforcement bar material 14A is formed into a zigzag shape, and the lattice reinforcement bar material 14A is temporarily deformed excessively with a forming jig in the direction opposite to the direction in which the lattice reinforcement bar material 14A returns to its original shape, thereby releasing the lattice reinforcement bar material 14A from the forming jig and eliminating the excess deformation. As shown in Figures 1 and 2, the lattice rebar forming process of the first embodiment includes a lattice rebar wrapping forming process (S102) in which the lattice rebar material 14A is wrapped spirally around a wrapping forming jig 20 to form a zigzag shape. The wrapping forming jig 20 has a twisted shape in the direction in which the lattice rebar material 14A is wrapped around it. The lattice rebar material 14A is twisted and deformed to conform to the twisted shape when wrapped around the wrapping forming jig 20, and is configured to deform back in a direction in which the twisted deformation is relieved when it is removed from the wrapping forming jig 20.

[0022] The main reinforcement bars 12 and the lattice reinforcement bars 14 are reinforcing bars such as deformed steel bars. The main reinforcement bars 12 are larger in diameter than the lattice reinforcement bars 14. Alternatively, the main reinforcement bars 12 may be the same diameter as the lattice reinforcement bars 14. Alternatively, the main reinforcement bars 12 may be thinner than the lattice reinforcement bars 14.

[0023] The wrapping and forming jig 20 has a configuration comprising a pair of rod-shaped main members 22 corresponding to a pair of main reinforcing bars 12, and a plurality of connecting members 24 that connect the pair of main members 22. The connecting members 24 are attached at predetermined intervals in the longitudinal direction of the main members 22, and the wrapping and forming jig 20 has a shape like a twisted ladder. More specifically, the wrapping and forming jig 20 is configured to be twisted around a central axis in the width direction in the same direction as the direction in which the lattice reinforcing bar material 14A is wrapped. The main members 22 are round rod-shaped bodies with a thickness similar to that of the main reinforcing bars 12 of the truss reinforcing bar 10. The length of the main members 22 is similar to that of the main reinforcing bars 12 or longer than that of the main reinforcing bars 12. The connecting members 24 are also round rod-shaped bodies, and as shown in the enlarged view in Figure 3, the connecting members 24 are thinner than the main members 22. Therefore, the winding forming jig 20 has a configuration in which the thickness of the portion between the ends, which is made up of the connecting members 24, is thinner than the thickness of the ends on both sides in the width direction, which are made up of the main member 22.

[0024] In the lattice rebar wrapping and forming process (S102), a linear or rod-shaped lattice rebar material 14A is wrapped spirally around the wrapping and forming jig 20. For example, the tip of a linear lattice rebar material 14A wound on a reel (not shown) is locked to the wrapping and forming jig 20, and while rotating the wrapping and forming jig 20 around its longitudinal axis, the lattice rebar material 14A is pulled out from the reel, and the wrapping and forming jig 20 or the reel is fed along the longitudinal direction of the wrapping and forming jig 20, thereby wrapping the lattice rebar material 14A spirally around the wrapping and forming jig 20. As a result, the lattice rebar material 14A is formed into a zigzag shape. At this time, the lattice rebar material 14A temporarily twists and deforms in the same direction as the wrapping direction, following the twisted shape of the wrapping and forming jig 20. Subsequently, when the lattice reinforcing bar material 14A is removed from the wrapping and forming jig 20, the lattice reinforcing bar material deforms in the opposite direction to the direction in which it was wrapped. This results in a planar lattice reinforcing bar 14 with torsional deformation eliminated or suppressed. The twist angle of the wrapping and forming jig 20 (the twist angle around the axis along the longitudinal direction per unit length in the longitudinal direction) can be appropriately determined according to the rigidity of the lattice reinforcing bar material 14A and the angle of the zigzag shape. Alternatively, the twist angle of the wrapping and forming jig 20 can be adjusted by actually wrapping the lattice reinforcing bar material 14A in a spiral shape around the wrapping and forming jig 20 so that the twist of the lattice reinforcing bar 14 after it is removed from the wrapping and forming jig 20 is eliminated or minimized.

[0025] In the main reinforcement joining process (S104), a pair of main reinforcements 12 are positioned along the bent portions of the lattice reinforcements 14 so as to be in contact with the inside of the bent portions, and are joined to the lattice reinforcements 14 by spot welding, arc welding, adhesive, etc. This completes the truss reinforcement 10. According to the above method for manufacturing the truss reinforcement 10, a planar truss reinforcement 10 equipped with planar lattice reinforcements 14 can be manufactured efficiently and easily.

[0026] Next, a second embodiment of the present invention will be described. In the lattice rebar wrapping and forming process (S102), the portion of the lattice rebar material 14A near the apex of the curve may not be sufficiently bent, that is, the processed shape viewed from the axial direction (longitudinal direction) of the truss rebar 10 may not be a 180° U-turn shape, but rather a slightly open processed shape, resulting in the lattice rebar 14 having a bulging shape. To resolve this and obtain a planar lattice rebar 14, the lattice rebar forming process of the second embodiment further includes a lattice rebar pressure forming process (S202) in which the lattice rebar material 14A is clamped and pressed from both sides in the thickness direction by pressure forming jigs 30. In the lattice rebar pressure forming process (S202), the lattice rebar material 14A wrapped around the wrapping and forming jig 20 is clamped and pressed from both sides in the thickness direction by a pair of pressure forming jigs 30. The pressure molding jig 30 is driven by an actuator (not shown) to contact or separate from the lattice reinforcing bar material 14A. The pressure molding jig 30 is shaped such that the portion of the jig corresponding to the portion between the bent portions of the lattice reinforcing bar material 14A protrudes in the thickness direction more than the portion corresponding to the bent portions, so that the portion of the jig corresponding to the portion between the bent portions of the lattice reinforcing bar material 14A is pressed in the thickness direction more than the portion corresponding to the bent portions of the jig 30. When the pressure molding jig 30 separates from the lattice reinforcing bar material 14A, the lattice reinforcing bar material 14A deforms back in a direction that relieves the deformation in the thickness direction of the portion between the bent portions of the lattice reinforcing bar material 14A. Other components are common to the first embodiment, so the same reference numerals as in the first embodiment are used for common components and their description is omitted.

[0027] The pressure forming jig 30 presses the lattice reinforcing bar material 14A in the thickness direction, pushing it further into the areas between the bent portions of the lattice reinforcing bar material 14A than into the bent portions. This temporarily deforms the areas between the bent portions of the lattice reinforcing bar material 14A into a shape that is pushed further in the thickness direction than into the bent portions. Subsequently, when the pressure forming jig 30 separates from the lattice reinforcing bar material 14A, the lattice reinforcing bar material 14A deforms back in a direction that eliminates the deformation in which the areas between the bent portions of the lattice reinforcing bar material 14A were pushed further in the thickness direction. As a result, a flat lattice reinforcing bar 14 is obtained, with the bulging shape in the thickness direction eliminated or suppressed. Note that the shape of the part of the pressure forming jig 30 that contacts the lattice reinforcing bar material 14A is not limited to the curved shape shown in Figure 4. As long as a flat lattice reinforcing bar 14 is obtained, the part of the pressure forming jig 30 that contacts the lattice reinforcing bar material 14A may have any other shape. For example, the shape of the part of the pressure molding jig 30 that contacts the lattice reinforcing bar material 14A may be such that only the central part in the vertical direction in Figure 4 protrudes. Alternatively, the shape may be such that only the part near the bent portion of the lattice reinforcing bar material 14A protrudes. Alternatively, the shape may be such that both the central part in the vertical direction in Figure 4 and the part near the bent portion of the lattice reinforcing bar material 14A protrude.

[0028] The wrapping and forming jig 20 has a shape in which the thickness of the portion made up of the connecting members 24 between the ends is thinner than the thickness of the ends on both sides in the width direction made up of the main members 22. Therefore, the lattice rebar wrapping and forming process (S102) and the lattice rebar press forming process (S202) can be performed continuously without removing the lattice rebar material 14A from the wrapping and forming jig 20, contributing to improved productivity. Furthermore, since the wrapping and forming jig 20 has a pair of rod-shaped main members 22 corresponding to a pair of main rebars 12 and a plurality of connecting members 24 that connect the pair of main members 22, a configuration in which the thickness of the portion between the ends is thinner than the thickness of the ends on both sides in the width direction can be easily realized by making the connecting members 24 thinner than the main members 22.

[0029] Furthermore, the length of the pressure forming jig 30 is shorter than the longitudinal length of the lattice reinforcing bar material 14A wrapped around the wrapping forming jig 20, and the lattice reinforcing bar material 14A may be pressurized in multiple stages, in multiple longitudinal sections. For example, the lattice reinforcing bar wrapping forming process (S102) and the lattice reinforcing bar pressure forming process (S202) may be performed in parallel, and the lattice reinforcing bar material 14A may be wrapped around the wrapping forming jig 20 to form a zigzag shape, while the portions of the lattice reinforcing bar material 14A wrapped around the wrapping forming jig 20 are sequentially pressurized with the pressure forming jig 30. Specifically, each time the wrapping forming jig 20 is rotated 180° or 360°, the lattice reinforcing bar material 14A immediately after being wrapped around the wrapping forming jig 20 may be pressurized in half-pitch or full-pitch sections. Alternatively, the lattice reinforcing bar material 14A may be pressure-molded at intervals of two or more pitches.

[0030] Alternatively, the lattice rebar pressure forming process (S202) may be performed after the lattice rebar wrapping and forming process (S102) is completed. In this case as well, the length of the pressure forming jig 30 may be shorter than the longitudinal length of the lattice rebar material 14A wrapped around the wrapping and forming jig 20, and the lattice rebar material 14A may be pressured in multiple stages, in sections along its length. Alternatively, the length of the pressure forming jig 30 may be shorter than the longitudinal length of the lattice rebar material 14A wrapped around the wrapping and forming jig 20, and the lattice rebar material 14A may be pressured in one stage along its entire length using multiple pairs of pressure forming jigs 30. Furthermore, the length of the pressure forming jig 30 may be equal to or greater than the longitudinal length of the lattice reinforcing bar material 14A wrapped around the wrapping forming jig 20, and the lattice reinforcing bar material 14A may be pressurized in one step along its entire length. If the twist angle of the wrapping forming jig 20 is large, the pressure forming jig 30 may be shaped to match the twisted shape of the wrapping forming jig 20. Alternatively, the pressure forming jig 30 may not be shaped to match the twisted shape of the wrapping forming jig 20, and its length may be shorter than the longitudinal length of the lattice reinforcing bar material 14A wrapped around the wrapping forming jig 20. In this case, the lattice reinforcing bar material 14A may be pressurized in multiple steps, adjusting the relative angle of the pressure forming jig 30 to the wrapping forming jig 20 to match the twisted shape of the wrapping forming jig 20.

[0031] Next, a third embodiment of the present invention will be described. In the third embodiment, after the lattice rebar wrapping and forming process (S102) is completed, the zigzag-shaped lattice rebar material 14A is removed from the wrapping and forming jig 20, and the lattice rebar pressure forming process (S202) is performed while the zigzag-shaped lattice rebar material 14A is held in place by the holder 40 shown in Figure 6. Other components are the same as those in the first and second embodiments, so the same reference numerals are used for common components as in the first and second embodiments, and their description will be omitted.

[0032] The configuration of the holder 40 is similar to that of the winding forming jig 20, the difference being that it is not twisted. Specifically, the pressure forming holder 40 has a configuration comprising a pair of rod-shaped main members 42 corresponding to a pair of main reinforcing bars 12 of the truss reinforcement 10, and a plurality of connecting members 44 that connect the pair of main members 42. The connecting members 44 are attached at predetermined intervals in the longitudinal direction of the main members 42, and the holder 40 has a straight, ladder-like shape without twisting. The main members 42 are round rod-shaped bodies with a thickness similar to that of the main reinforcing bars 12 of the truss reinforcement 10. The length of the main members 42 is similar to that of the main reinforcing bars 12, or longer than that of the main reinforcing bars 12. The connecting members 44 are also round rod-shaped bodies, and the connecting members 44 are thinner than the main members 42. Therefore, the thickness of the portion between the ends composed of the connecting members 44 is thinner than the thickness of the ends on both sides in the width direction composed of the main members 42.

[0033] As described above, when the lattice reinforcing bar material 14A is removed from the wrapping and forming jig 20, the lattice reinforcing bar material 14A deforms back in a direction that eliminates the twist angle, so it can be easily attached to the holder 40, which has a straight, ladder-like shape without twisting. Since the lattice reinforcing bar material 14A held by the holder 40 is in a form where the twist deformation has been eliminated or suppressed, it is easier to apply even pressure with the pressure forming jig 30 than when it is twisted. For example, even if the twist angle of the wrapping and forming jig 20 is large, it is possible to apply even pressure to the lattice reinforcing bar material 14A over its entire length in one go with the pressure forming jig 30, which has a straight shape that does not conform to the twisted shape of the wrapping and forming jig 20. Alternatively, the length of the pressure forming jig 30 may be shorter than the length of the lattice reinforcing bar material 14A held by the holder 40, and the lattice reinforcing bar material 14A may be pressurized in multiple stages, in sections along its length.

[0034] Furthermore, if twisting of the lattice reinforcing bar material 14A due to return deformation is unlikely to occur during the lattice reinforcing bar wrapping and forming process (S102), the lattice reinforcing bar wrapping and forming process (S102) may be performed using the holder 40 instead of the wrapping and forming jig 20, and the lattice reinforcing bar pressure forming process (S202) may be performed continuously without removing the lattice reinforcing bar material 14A from the holder 40.

[0035] Next, a fourth embodiment of the present invention will be described. As shown in Figures 7 and 8, in the fourth embodiment, the lattice reinforcing bar material 14A, which has been formed into a zigzag shape in the lattice reinforcing bar wrapping process (S102), is removed from the wrapping jig 20, and then the main reinforcing bar joining process (S104) is performed to join the main reinforcing bar 12 to the lattice reinforcing bar material 14A, and then the lattice reinforcing bar pressure forming process (S202) is performed. Other components are common to the first to third embodiments, so the same reference numerals are used for common components as in the first to third embodiments and their description is omitted. In the fourth embodiment, instead of the holder 40 of the third embodiment, the main reinforcing bar 12 plays the role of the main member 42 of the holder 40. In this case as well, the pressure forming jig 30 can press down on the lattice reinforcing bar material 14A in the thickness direction in the portion between the bent portions of the lattice reinforcing bar material 14A, more so than in the bent portions. Furthermore, since the lattice reinforcement material 14A, which has been removed from the wrapping forming jig 20 and to which the main reinforcement bars 12 have been joined, is in a form in which torsional deformation has been eliminated or suppressed, it is easier to apply uniform pressure with the pressure forming jig 30 than when it is torsionally deformed. If there is a possibility that the pressure forming jig 30 may push the lattice reinforcement material 14A excessively in the thickness direction, a member in a form corresponding to the multiple connecting members 44 of the holder 40 (for example, a plate-shaped member with the same diameter and thickness as the connecting members 44) may be inserted into the zigzag-shaped lattice reinforcement material 14A between the pair of main reinforcement bars 12, and the lattice reinforcement pressure forming process (S202) may be performed.

[0036] Furthermore, if twisting deformation of the lattice reinforcing bar material 14A is unlikely to occur during the lattice reinforcing bar wrapping process (S102), the lattice reinforcing bar wrapping process (S102) may be performed using the holder 40 instead of the wrapping jig 20, the lattice reinforcing bar material 14A may be removed from the holder 40, and then the main reinforcing bar joining process (S104) may be performed to join the main reinforcing bars 12 to the zigzag-shaped lattice reinforcing bar material 14A before performing the lattice reinforcing bar pressure forming process (S202).

[0037] Next, a fifth embodiment of the present invention will be described. As shown in Figure 9, in the fifth embodiment, instead of the wrapping forming jig 20 of the first embodiment, which has a configuration like a twisted ladder, a wrapping forming jig 50 in the form of a twisted strip-shaped plate is used to perform the lattice rebar wrapping forming process (S102). Other components are the same as in the first embodiment, so the same reference numerals are used for common components as in the first embodiment and their description will be omitted. The wrapping forming jig 50 has a width equal to that of the wrapping forming jig 20, and a thickness equal to the diameter of the main member 22 of the wrapping forming jig 20. The end of the wrapping forming jig 50 in the width direction may be a side surface with a semicircular cross-section having a diameter equal to the diameter of the main member 22 of the wrapping forming jig 20. Even when using the wrapping forming jig 50 in the form of a twisted strip-shaped plate instead of the wrapping forming jig 20 of the first embodiment, a planar lattice rebar 14 can be obtained in which torsional deformation is eliminated or suppressed. Furthermore, when performing the lattice rebar pressure forming process (S202), the lattice rebar material 14A can be removed from the winding forming jig 50, and the lattice rebar pressure forming process (S202) can be performed while the zigzag-shaped lattice rebar material 14A is held in place by the holder 40, as in the third embodiment. Alternatively, as in the fourth embodiment, the zigzag-shaped lattice rebar material 14A can be removed from the winding forming jig 50, the main reinforcing bars 12 can be joined to the lattice rebar material 14A, and then the lattice rebar pressure forming process (S202) can be performed.

[0038] Next, a sixth embodiment of the present invention will be described. As shown in Figure 10, in the sixth embodiment, instead of the wrapping forming jig 50 of the fifth embodiment, which is in the form of a twisted strip-shaped plate, a wrapping forming jig 60 in the form of a strip-shaped plate without twisting is used to perform the lattice rebar wrapping forming process (S102). Other components are the same as in the sixth embodiment, so the same reference numerals are used for common components as in the sixth embodiment and their description is omitted. The wrapping forming jig 60 has the same width and thickness as the wrapping forming jig 50. Note that the end of the wrapping forming jig 60 in the width direction may be a side surface with a semicircular cross-section having a diameter equal to the diameter of the main member 22 of the wrapping forming jig 20 of the first embodiment. In the lattice rebar wrapping and forming process (S102), if twisting of the lattice rebar material 14A due to return deformation is unlikely to occur, a flat lattice rebar 14 can be obtained by using a wrapping and forming jig 60, which is in the form of a strip-shaped plate without twisting, instead of the wrapping and forming jig 50 of the fifth embodiment. If the lattice rebar material 14A is formed into a shape that bulges in the thickness direction by the lattice rebar wrapping and forming process (S102), the lattice rebar pressure forming process (S202) is performed. For example, the lattice rebar material 14A is removed from the wrapping and forming jig 60, and the lattice rebar pressure forming process (S202) is performed while the zigzag-shaped lattice rebar material 14A is held by the holder 40 as in the third embodiment. Alternatively, as in the fourth embodiment, the zigzag-shaped lattice reinforcing bar material 14A may be removed from the winding and forming jig 60, the main reinforcing bars 12 may be joined to the lattice reinforcing bar material 14A, and then the lattice reinforcing bar pressure forming process (S202) may be performed.

[0039] Next, a seventh embodiment of the present invention will be described. The seventh embodiment relates to a truss reinforcement 70 shown in Figure 11. The truss reinforcement 70 has a configuration in which cross reinforcement bars 72 are added to the truss reinforcement 10 of the first embodiment. When the truss reinforcement 70 is laid on a horizontal mortar layer, the cross reinforcement bars 72 are installed between the bent portion of the lattice reinforcement 14 and the main reinforcement bars 12 in a direction that intersects with the lattice reinforcement 14, so that the cross reinforcement bars 72 extend in the vertical direction. As shown in Figure 12, in the seventh embodiment, a cross reinforcement joining process (S302) is performed between the lattice reinforcement wrapping process (S102) and the main reinforcement joining process (S104) to join the cross reinforcement bars 72 to the lattice reinforcement 14. Other components are common with the first embodiment, so the same reference numerals as in the first embodiment will be used for common components and their description will be omitted.

[0040] The crossing reinforcement bars 72 extend vertically perpendicular to the boundary of the mortar layer, providing a reinforcing effect that prevents peeling and relative sliding at the boundary of the mortar layer. Furthermore, the embedding of the crossing reinforcement bars 72 in the upper and lower mortar layers also suppresses the warping of the truss reinforcement bars 70. In addition, since the crossing reinforcement bars 72 extending vertically are also reinforced by laying the truss reinforcement bars 70 in the mortar layer, the work of reinforcing other vertically extending reinforcement bars is unnecessary, making the reinforcement work easier. The crossing reinforcement bars may also have a rod-shaped main part and a bent end formed at one end of the main part. For example, the crossing reinforcement bars may be L-shaped or J-shaped. The bent part has the function of anchoring the reinforcement bars as a hook, so the interlayer separation (peeling) can be prevented or suppressed, and the interlayer strength can be increased. The crossing reinforcement bars 72 may also be installed in the parts between the bent parts of the lattice reinforcement bars 14 (the straight parts that make up the diagonal members). In this case, the cross reinforcement joining process (S302) may be performed after the main reinforcement joining process (S104). Furthermore, when manufacturing the truss reinforcement 70 with cross reinforcements 72, the lattice reinforcement pressure forming process (S202) may also be performed as in the second to fourth embodiments.

[0041] Next, an eighth embodiment of the present invention will be described. The eighth embodiment relates to a truss reinforcement bar 80 shown in Figure 13. The truss reinforcement bar 80 is configured to have two lattice reinforcement bars 14 in addition to the truss reinforcement bars 10 and 70 of the first to seventh embodiments. The two lattice reinforcement bars 14 are installed in contact with each other in a double helix. Other components are common to the first to seventh embodiments, so the same reference numerals as in the first to seventh embodiments will be used for common components and their description will be omitted. When the lattice reinforcement bar material 14A is bent into a zigzag shape, a minimum bending radius is specified to avoid damage to the bent portion and a reduction in strength. The minimum bending radius is smaller the smaller the diameter of the reinforcement bar. For example, if the main reinforcement bar 12 is D10, the inner circumference of the bent portion of the D4 lattice reinforcement bar 14 bent at the minimum bending radius will coincide with the outer circumference of the main reinforcement bar 12, so the lattice reinforcement bar 14 needs to be D4 or thinner. On the other hand, thin lattice reinforcing bars 14 may not provide sufficient strength. In contrast, truss reinforcing bars 80 have two lattice reinforcing bars 14, thus providing twice the strength. Depending on the required strength, a configuration with three or more lattice reinforcing bars 14 may also be used.

[0042] When manufacturing a truss reinforcement with multiple lattice bars, multiple lattice bars 14 can be formed by performing a lattice bar wrapping process (S102) or a lattice bar pressure forming process (S202) on multiple lattice bar materials 14A arranged in parallel, and then joining the multiple lattice bars 14 to the main reinforcement 12 in the main reinforcement joining process (S104). Alternatively, as in the first to seventh embodiments, the lattice bars 14 may be formed one by one, and then the multiple lattice bars 14 may be joined together to the main reinforcement 12 in the main reinforcement joining process (S104). [Industrial applicability]

[0043] This invention can be used to manufacture truss reinforcement bars suitable for construction of structures using a 3D printer for construction. [Explanation of Symbols]

[0044] 10, 70, 80 truss reinforcement bars 12 Main reinforcing bars 14 Lattice Reinforcement Bars 14A Lattice Reinforcement Material 20, 50, 60 jigs for winding molding 22, 42 Main components 24, 44 Connecting material 30. Jig for pressure molding 40 Holder 72 Crossing reinforcement bars S102 Lattice Reinforcement Wrapping and Forming Process S104 Main reinforcement bar joining process S202 Lattice Reinforcement Pressure Forming Process S302 Cross-reinforcement bar joining process

Claims

1. A method for manufacturing a truss reinforcement, comprising a pair of rod-shaped main reinforcements and a pair of zigzag-shaped lattice reinforcements that engage with the pair of main reinforcements in a spiral manner, A method for manufacturing a truss reinforcing bar, comprising a lattice reinforcing bar forming step in which a lattice reinforcing bar material is formed into the zigzag shape, and the lattice reinforcing bar material is temporarily deformed excessively by a forming jig in the direction opposite to the direction in which the lattice reinforcing bar material returns to its original shape, and the lattice reinforcing bar material is released from the forming jig, thereby causing the lattice reinforcing bar material to return to its original shape and eliminating the excess deformation.

2. In claim 1, The lattice rebar forming process includes a lattice rebar wrapping and forming process in which the lattice rebar material is wrapped around a wrapping and forming jig in the spiral shape to form the zigzag shape. The aforementioned winding and forming jig has a shape that is twisted in the direction in which the lattice reinforcing material is wound. A method for manufacturing a truss reinforcing bar, wherein the lattice reinforcing bar material is wrapped around the wrapping forming jig, causing it to twist and deform to conform to the twisted shape, and is removed from the wrapping forming jig, causing it to deform back in a direction that eliminates the twisting deformation.

3. In claim 2, A method for manufacturing truss reinforcement, wherein the winding forming jig has a pair of rod-shaped main members corresponding to a pair of main reinforcement bars, and a plurality of connecting members connecting the pair of main members.

4. In claim 1, The lattice rebar forming process includes a lattice rebar pressure forming process in which the lattice rebar material formed into a zigzag shape is clamped and pressed from both sides in the thickness direction with a pressure forming jig, A method for manufacturing truss reinforcement, wherein the pressure molding jig has a shape such that the portion corresponding to the portion between the bent portions of the lattice reinforcement material protrudes in the thickness direction more than the portion corresponding to the bent portions, so as the pressure molding jig separates from the lattice reinforcement material, the lattice reinforcement material deforms in a direction that eliminates the deformation in which the portion between the bent portions of the lattice reinforcement material was pushed in the thickness direction.

5. In claim 4, The lattice rebar forming process further includes a lattice rebar wrapping and forming process in which the lattice rebar material is wrapped around a wrapping and forming jig in the spiral shape to form the zigzag shape, The aforementioned winding forming jig has a shape in which the thickness of the portion between the ends is thinner than the thickness of the ends on both sides in the width direction. A method for manufacturing truss reinforcing bars, comprising the process of pressure forming a lattice reinforcing bar, wherein the lattice reinforcing bar material wrapped around the winding forming jig is clamped and pressurized from both sides in the thickness direction by the pressure forming jig.

6. A forming jig used in the process of forming the lattice reinforcement of a truss reinforcement, which has a pair of rod-shaped main reinforcements and a pair of zigzag-shaped lattice reinforcements that engage with the pair of main reinforcements in a spiral manner, A forming jig configured such that the lattice reinforcing bar material, which is formed into a zigzag shape, is temporarily deformed in the direction opposite to the direction in which it returns to its original shape, and then released, causing the lattice reinforcing bar material to return to its original shape and the excess deformation to be eliminated.

7. In claim 6, The molding jig is a winding molding jig in which the lattice reinforcing material is wound in the spiral shape, The aforementioned lattice reinforcing material has a twisted shape in the direction in which it is wrapped, A forming jig configured such that when the lattice reinforcing bar material is wrapped around it, the lattice reinforcing bar material twists and deforms to conform to the twisted shape, and when the lattice reinforcing bar material is removed, the lattice reinforcing bar material deforms back in a direction that eliminates the twisting deformation.

8. In claim 7, A molding jig having a configuration comprising a pair of rod-shaped main members corresponding to a pair of main reinforcing bars, and a plurality of connecting members connecting the pair of main members.

9. In claim 7 or 8, A jig for winding and forming, having a shape in which the thickness of the portion between the ends is thinner than the thickness of the ends in the width direction corresponding to a pair of main reinforcing bars.

10. In claim 6, The molding jig is a pressure molding jig that clamps the zigzag-shaped lattice reinforcing bar material from both sides in the thickness direction and applies pressure. A molding jig configured such that the portion between the bent portions of the lattice reinforcing bar material is pressed and compressed in the thickness direction more than the portion between the bent portions, the portion corresponding to the portion between the bent portions protrudes in the thickness direction more than the portion corresponding to the bent portions, and the lattice reinforcing bar material deforms in a direction that relieves the deformation in which the portion between the bent portions of the lattice reinforcing bar material is pressed in the thickness direction when the jig moves away from the lattice reinforcing bar material.

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