JP6147404B1 - Threaded bar joint of deformed bar and method for manufacturing the same - Google Patents

Abstract

Disclosed is a deformed reinforcing bar screw-type reinforcing bar joint and a method for manufacturing the same, which is excellent in productivity and does not cause a practical problem of yield strength reduction due to processing of a male screw part.
A reinforcing bar joint for mutually connecting a pair of reinforcing bars 1 and 1 which are deformed reinforcing bars having protrusions 1b on the outer periphery of a reinforcing bar main body 1a. A cylindrical coupler 2 that is screwed into the male screw portions 1c and 1c of both the reinforcing bars 1 and 1 is provided. The male thread portion 1c of each reinforcing bar 1 has a thread groove diameter D3 smaller than the reinforcing bar main body outer diameter D1, and screw thread diameters D3 ₂ and D3 ₂ ′ larger than the reinforcing bar main body outer diameter D1 and smaller than the maximum diameter D2. The hardness of the male screw portion 1c is harder than other portions of the reinforcing bar 1 due to work hardening accompanying screw formation by rolling. A lock nut may be further provided.
[Selection] Figure 1

Description

  The present invention relates to a threaded reinforcing bar joint for deformed reinforcing bars used in reinforced concrete and a method for manufacturing the same.

  In reinforced concrete, deformed reinforcing bars are generally used as reinforcing bars because of their excellent fixability. There are various types of reinforcing bar joints that connect deformed reinforcing bars, such as lap joints, and threaded reinforcing bar joints that simplify the bar arrangement and shorten the construction period. In threaded rebar joints, when the male thread part is simply formed on the rebar by cutting, the yield strength decreases due to the cross-sectional defect, so a large diameter part is formed in the rebar, and the male thread is rolled to this large diameter part. Has been proposed (for example, Patent Document 1). In this proposed example, it is also proposed to eliminate play by providing a lock nut.

Japanese Patent No. 5869716

  The reinforcing bar joint proposed by Patent Literature 1 has an advantage that the male screw part is excellent in proof stress because a large diameter part is provided in the reinforcing bar and a male screw is processed in the large diameter part. However, since the large-diameter portion needs to be formed, the manufacturing cost increases. If the large-diameter portion is formed on the reinforcing bar material at the time of roll forming of the deformed reinforcing bar nodes and ribs, an increase in manufacturing cost can be suppressed to some extent, but it is not sufficient. Further, according to roll forming, the large diameter portion of the reinforcing bar is formed at a constant pitch according to the roll diameter, but a slight pitch shift occurs. Therefore, it is necessary to adjust the position for obtaining the large diameter portion of the reinforcing bar end portion for obtaining a pair of male screw portions by cutting at the center in the length direction of the large diameter portion, and the productivity is reduced as the mass production is performed. .

  An object of the present invention is to provide a threaded reinforcing bar joint of a deformed reinforcing bar and a method of manufacturing the same, which is excellent in productivity and does not cause a practical problem of yield strength reduction due to processing of a male screw part. is there.

The threaded reinforcing bar joint of the first deformed reinforcing bar according to the present invention has a pair of reinforcing bars connected to each other by a threaded cylindrical coupler that is provided at the ends of both reinforcing bars and is screwed into the male threaded part, and one or both of the pair rebar, the outer periphery of the round shaft-like reinforcing bar body, the long side direction in an interval have a plurality of knuckles, and the deformed bar is deformed bars having a ridge extending longitudinally threaded rebar joint In
Wherein the end of one or both of the reinforcing bar, the screw groove diameter having a thin male threaded portion than the reinforcing bar body, the male screw portion is thicker portions plurality of locations is a crest diameter of the width corresponding to the knuckles The remainder is a portion with a small thread diameter except for the same circumferential direction as the ridge, the thread groove diameters of both portions are the same, and the thread groove depth of the portion with the thin thread diameter is the same. , 70% or more of the thread groove depth of the thick part of the thread diameter, and the thread diameter of the thick part of the thread diameter is thicker than the rebar main body of the rebar and includes the ridge. Further, the male screw portion is harder than other portions of the reinforcing bar or has a higher tensile strength, and includes a cylindrical coupler that is screwed into the male screw portion of the both reinforcing bars.

  According to this configuration, both the reinforcing bars can be connected by screwing the male threaded portion of the pair of reinforcing bars into the coupler, and the arrangement of the reinforcing bars can be simplified and the construction period can be shortened as in the case of a general reinforcing bar joint. Since the male thread portion has a thread groove diameter thinner than that of the reinforcing bar main body and a thread diameter larger than that of the reinforcing bar main body and smaller than the maximum diameter, the deformed reinforcing bar used as a material is not subjected to a lower process, or It can be formed simply by applying a sub-process of round processing. Since the male threaded portion is formed by threading the deformed reinforcing bar without subjecting it to a large downsizing such as increasing the diameter, the productivity is excellent. Since the thread groove diameter of the male thread part is narrower than the main body of the reinforcing bar, there is a concern that the strength of the joint part such as tensile strength of the reinforcing bar will be reduced, but the strength of the male thread part is harder than other parts, so the yield strength is reduced. Can be compensated for and sufficient proof stress can be obtained. The degree of hardness or strength required to compensate for the decrease in yield strength due to the groove processing of the male screw portion is sufficient to be the work hardening (also called plastic hardening) obtained by rolling the male screw portion. Therefore, if a male thread part is rolled to a deformed reinforcing bar as it is, the hardness required for the male thread part can also be obtained. For this reason, the process for exclusive use for raising the hardness of an external thread part is unnecessary, and it is excellent also in productivity from this. If the coupler is prepared, the subsequent work only needs to be performed by cutting the deformed reinforcing bar and rolling the male screw part, and can also be performed at the construction site.

Another embodiment of the threaded reinforcing bar joint of the deformed reinforcing bar according to the present invention includes a pair of reinforcing bars connected to each other by a threaded cylindrical coupler that is provided at the ends of both reinforcing bars and screwed into the male threaded portion. In the threaded rebar joint of deformed rebar where the rebar is a deformed rebar,
The one or both reinforcing bars are deformed reinforcing bars having a plurality of nodes spaced apart in the longitudinal direction without having protrusions extending in the longitudinal direction on the outer circumference of the round shaft-shaped reinforcing bar body,
Wherein the end of one or both of the reinforcing bar, the screw groove diameter having a thin male threaded portion than the reinforcing bar body, the male screw portion is thicker portions plurality of locations is a crest diameter of the width corresponding to the knuckles The remainder is a portion with a thin thread diameter, the thread groove diameters of both portions are the same, and the thread groove depth of the thin thread diameter portion is the thread groove depth of the thick thread diameter portion. The thread diameter of the portion having a large thread diameter is 70% thicker than the rebar main body of the rebar and smaller than the maximum diameter including the protrusions, and the hardness of the male screw portion is the rebar. It is characterized by comprising a cylindrical coupler that is harder or has higher tensile strength than the other parts and that is screwed into the male threaded portions of the two reinforcing bars.

According to this configuration, in addition to the effects described for the threaded reinforcing bar joint of the first deformed reinforcing bar,
The following effects can be obtained.
Conventional deformed reinforcing bars called bamboo rebars are generally composed of a round shaft-shaped reinforcing bar body and joints / ribs, but the ribs also contribute to the tensile strength and account for about 4%. When the male thread portion is machined on the deformed reinforcing bar, the rib is interrupted at the thread groove portion, and the tensile strength that contributes to the cross-sectional area of the rib is reduced. As a result, the male screw portion becomes a local weak portion of the tensile strength.
In this regard, it is possible to avoid the male screw portion being a locally weak portion of the proof stress by making the reinforcing bar into a shape that does not have protrusions such as ribs extending in the longitudinal direction as described above.
If the ridges are simply eliminated, the tensile strength of the entire rebar will be reduced by that amount, but the male threaded portion has increased tensile strength due to work hardening by rolling, etc., so the necessary strength was maintained. It is. In order to ensure further reliability, it is only necessary to use a reinforcing bar whose diameter is larger than that of the ribs and the like.

In the case of using a deformed reinforcing bar that does not have a protrusion extending in the longitudinal direction, the one or both reinforcing bars have two sections 180 ° apart from each other on the outer peripheral surface, and the cross section perpendicular to the axial direction is the outer periphery of the reinforcing bar main body. You may make it have the strip | belt-shaped flat part which is a straight line used as the one part arc of the circle which comprises a surface over the full length of an axial direction.
When manufacturing a deformed reinforcing bar having the node, according to general rolling, a protrusion that becomes the rib is generated by a gap between opposing rolling rolls. However, even if a rib is generated during rolling, it is only necessary to drop the rib to form the belt-like flat portion, whereby a rolling roll facility in which the processing of the node portion is a deformed reinforcing bar having a general node portion and a rib. Even if it carries out using, it becomes a deformed reinforcing bar with a knot which does not have a ridge extending in the longitudinal direction.

In this invention, you may make it have a lock nut screwed together in the said external thread part of the said reinforcing bar, and contact | abutted to the end surface of the said coupler.
When the lock nut is provided in this way, there is no backlash at the screw coupling portion, and the surface where the threads of the male screw portion and the female screw portion of the coupler come into contact with each other changes when the tensile force is applied and when the compressive force is applied. Therefore, the requirements of both tensile strength and compression strength can be satisfied.

The manufacturing method of the threaded reinforcing bar joint of the deformed reinforcing bar of the present invention is a method of manufacturing the threaded reinforcing bar joint of the deformed reinforcing bar having any one of the configurations of the present invention, and has a deformed reinforcing bar having a protrusion on the outer periphery of the reinforcing bar main body. A cutting process in which the male screw part is cut into an arbitrary length, a male screw rolling process in which the male screw part is processed by rolling without subjecting the end of the cut reinforcing bar to a diameter expansion process, and a pair in which the male screw part is processed Preparing a coupler to be screwed into the male thread portion of the reinforcing bar.
According to this method, it is possible to obtain a reinforcing bar with a male screw part constituting a threaded reinforcing bar joint by simply cutting the deformed reinforcing bar into an arbitrary length and rolling the male screw part. Since the male threaded part is processed by rolling, the hardness required for the male threaded part to compensate for the cross-sectional defects associated with threading is also obtained by work hardening associated with rolling, especially for increasing the hardness. No process is required. Therefore, excellent productivity can be obtained.

In the manufacturing method of the threaded reinforcing bar joint of the deformed reinforcing bar according to the present invention, a perfect circle having an outer diameter to the extent that the protrusion is substantially eliminated in a length range in which the male thread portion is formed at the end of the reinforcing bar after the cutting process. A rolling process may be included, and the rolling may be performed after the machining process.
Even if the deformed reinforcing bar is rolled as it is, the necessary male screw part can be obtained. However, because the deformed reinforcing bar has protrusions such as nodes and ribs, burrs may be generated by rolling. By performing rolling after the perfect circle processing, the generation of the burr is eliminated and a male screw part can be obtained beautifully. The perfect circle processing for eliminating the generation of burrs may be to the extent that the protrusions such as the joints and ribs are removed, and the base end of the protrusions may remain. It is not preferable to make it thinner than that because the yield strength is reduced by reducing the diameter.

The threaded reinforcing bar joint of the first deformed reinforcing bar according to the present invention has a pair of reinforcing bars connected to each other by a threaded cylindrical coupler that is provided at the ends of both reinforcing bars and is screwed into the male threaded part, and one or both of the pair rebar, the outer periphery of the round shaft-like reinforcing bar body, the long side direction in an interval have a plurality of knuckles, and the deformed bar is deformed bars having a ridge extending longitudinally threaded rebar joint in the on the end of one or both of the reinforcing bar, the screw groove diameter having a thin male threaded portion than the reinforcing bar body, the male screw portion, a plurality of locations of a width corresponding to the knuckles of the crest diameter The thick part and the rest are the parts with the thin thread diameter except for the same circumferential direction as the ridges, and the thread groove diameters of both parts are the same as each other. The groove depth is 70% or more of the thread groove depth of the portion having a large thread diameter, Crest diameter of the thick portion of major diameter is narrower than the maximum diameter including thick and the ridge than the reinforcing bar body of the reinforcing bar, the hardness of the male screw portion is harder than other portions of the reinforcing bars, wherein Since a cylindrical coupler that is screwed into the male threaded portion of both reinforcing bars is provided, the productivity is excellent, and the necessary yield strength can be obtained without causing a practical problem of a decrease in yield strength due to processing of the male threaded portion.

Another embodiment of the threaded reinforcing bar joint of the deformed reinforcing bar according to the present invention includes a pair of reinforcing bars connected to each other by a threaded cylindrical coupler that is provided at the ends of both reinforcing bars and screwed into the male threaded portion. In the threaded rebar joint of deformed rebar where the rebar is a deformed rebar,
The one or both reinforcing bars are deformed reinforcing bars having a plurality of nodes spaced apart in the longitudinal direction without having protrusions extending in the longitudinal direction on the outer circumference of the round shaft-shaped reinforcing bar body,
Wherein the end of one or both of the reinforcing bar, the screw groove diameter having a thin male threaded portion than the reinforcing bar body, the male screw portion is thicker portions plurality of locations is a crest diameter of the width corresponding to the knuckles The remainder is a portion with a thin thread diameter, the thread groove diameters of both portions are the same, and the thread groove depth of the thin thread diameter portion is the thread groove depth of the thick thread diameter portion. The thread diameter of the portion having a large thread diameter is 70% thicker than the rebar main body of the rebar and smaller than the maximum diameter including the protrusions, and is screwed into the male thread portions of both rebars. Because it has a cylindrical coupler that fits together, it has excellent productivity and the necessary strength can be obtained without causing a practical problem of reduced yield strength due to processing of the male threaded portion. It is avoided that it becomes a part.

  The manufacturing method of the threaded reinforcing bar joint of the deformed reinforcing bar of the present invention is a method of manufacturing the threaded reinforcing bar joint of the present invention, and is a method of cutting the deformed reinforcing bar having a protrusion on the outer periphery of the reinforcing bar main body to an arbitrary length. The process, a male thread rolling process in which the male thread part is processed by rolling without subjecting the end of the cut reinforcing bar to a diameter expansion process, and the male thread part of the pair of reinforcing bars in which the male thread part is machined. And a step of preparing a coupler to be manufactured, a threaded steel rebar joint capable of obtaining the required strength of the male thread portion can be manufactured with high productivity.

(A) is sectional drawing of the threaded reinforcement joint of the deformed reinforcing bar which concerns on 1st Embodiment of this invention, (B) is an expanded sectional view of the IB part of the same figure (A). It is a front view of the decomposition | disassembly state of the screw-type rebar joint. It is explanatory drawing of the manufacturing process of the screw-type rebar joint. It is sectional drawing of the screw-type reinforcing bar joint of the deformed reinforcing bar which concerns on other embodiment of this invention. It is a front view of the decomposition | disassembly state of the screw-type rebar joint. It is the action explanatory view. It is sectional drawing of the screw-type reinforcing bar joint of the deformed reinforcing bar which concerns on further another embodiment of this invention. It is a front view of the decomposition | disassembly state of the screw-type rebar joint. It is explanatory drawing of the manufacturing process of the screw-type rebar joint. (A) is a front view and a side view showing an example of a deformed reinforcing bar shape and dimensions used in the embodiment, and (B) is a front view and a side view showing an example of deformed reinforcing bar shapes and dimensions used in the first embodiment. It is. It is sectional drawing of the screw-type reinforcing bar joint of the deformed reinforcing bar which concerns on other embodiment of this invention. It is a front view of the decomposition | disassembly state of the screw-type rebar joint. (A) is a sectional view of a threaded reinforcing bar joint of a deformed reinforcing bar according to another embodiment of the present invention, (B) is a sectional view taken along the line XIIIB-XIIIB of FIG. (A), and (C) is a modification of the deformed reinforcing bar. It is sectional drawing equivalent to the figure (B). It is process explanatory drawing of the manufacturing process of the screw-type rebar joint. It is explanatory drawing of the rolling of a reinforcing bar and the rib removal process in the screw-type reinforcing bar joint. It is sectional drawing of the screw-type reinforcing bar joint of the deformed reinforcing bar which concerns on further another embodiment of this invention. It is sectional drawing which shows the example which attached the fixing board by the screw coupling | bonding using the reinforcing bar of the screw-type reinforcing bar joint. (A), (B) is a front view of each example of an identification board.

  A first embodiment of the present invention will be described with reference to FIGS. The threaded reinforcing bar joint of the deformed reinforcing bar is a reinforcing bar joint for connecting a pair of reinforcing bars 1 and 1, and has a male threaded portion 1 c at the opposite end of the pair of reinforcing bars connected to each other. The coupler 2 is screwed over the male screw portions 1c and 1c. Both male screw portions 1c and 1c are screws in the same direction in this embodiment, but may be reverse screws. The coupler 2 has a steel screw cylinder shape in which a female screw portion 2a that is screwed into the male screw portions 1c and 1c is formed. The outer peripheral surface of the coupler 2 may be a cylindrical surface, or a part or the whole of the length direction may be a polygon that engages with a screw tightening tool (not shown) or a flat surface in part. It may have a shape.

  Each reinforcing bar 1 is a deformed reinforcing bar having a protrusion 1b on the outer peripheral surface of a round shaft-shaped reinforcing bar main body 1a. In this embodiment, the protrusion 1b is composed of a node 1ba extending in the circumferential direction at regular intervals in the longitudinal direction of the reinforcing bar and a rib 1bb extending in the longitudinal direction. Two ribs 1bb are provided at a position 180 degrees away from the reinforcing bar main body 1a. Each node 1ba has an annular shape that continues around the entire circumference. The node portion 1ba may have a shape in which half circumferences extending between the two ribs 1bb and 1bb are alternately arranged in the longitudinal direction of the reinforcing bar. Further, the protrusion 1b is not limited to the shape formed by the node portion 1ba and the rib 1bb as described above, and is formed in a spiral shape by one or two spirals, and the space between the intersecting portions is It may be a diamond shape or the like.

  The male screw portions 1c and 1c of the reinforcing bars 1 and 1 are rolling screws, and at least the surface layer is harder than other portions of the reinforcing bars 1 and 1 by work hardening (also called plastic hardening). .

  The relationship between the diameters of the male screw portion 1c will be described. The male screw portion 1c of the reinforcing bar 1 has a base end of the node portion 1ba and the rib 1bb in order to improve the accuracy of threading the node portion 1ba and the rib 1bb as will be described later. In order to perform threading after performing round processing to such an extent that remains, the dimensions are different depending on whether or not the node 1ba is present as follows. In addition, since the location with the rib 1bb is the same as the location with the node 1ba, considering the entire circumference, the axial width portion with the node 1ba and the axial width portion without the node 1ba have the male screw portion 1c. The diameter dimensions are the same.

The relationship between the diameters will be specifically described. Since the diameter D5 (FIG. 1 (B)) of the perfect circle processed by the perfect circle is larger than the outer diameter D1 of the reinforcing bar main body 1a, the portion of the reinforcing bar main body 1a in the length range where the circular processing is performed remains as an unprocessed portion. It's ruined. Male screw portion 1c, a screw groove diameter D3 ₁ is smaller than the outer diameter D1 of the reinforcing bar body, is formed over the circularity machining portion 1ba 'knuckles 1ba diameter larger reinforcing bar body 1a, and from this . Therefore, as shown in FIG. 1B, the thread diameter of the male threaded portion 1c differs between the location of the reinforcing bar main body 1a and the portion 1ba ′ in which the node portion 1ba is processed into a perfect circle. The screw groove diameter is the same D3 ₁ both. Screw groove depth h1 of the male screw portion 1c formed in the reinforcing bar body 1a is the screw groove depth _{h 0} of the circularity machining portion 1ba 'knuckles 1ba, for example 75% to 80%, in this example 75%. In addition, if the ratio h1 / h0 of the thread groove depth is 70% or more, it is confirmed by simulation that there is no hindrance to fastening as a reinforcing bar joint even in a portion threaded on the reinforcing bar main body 1a in the male screw portion 1c. Has been.

An example of the diameter of each part of the reinforcing bar 1 is as follows. In the reinforcing bar having a nominal diameter of D19, when the male threaded part 1c having a pitch of 2.5 is processed at M20, the outer diameter D1 of the reinforcing bar body 1a is 17.88, the maximum diameter. D2 (node portion outer diameter of 1ba) is 20.68, crest diameter D3 ₂ is 19.674, screw effective diameter D3 ₀ is 18.05, the screw groove diameter D3 ₁ is 16.607 (unit: mm) .

  The length L of the male screw portion 1c only needs to be a required screwing length with respect to the coupler 2, but it is preferable that the length of the coupler 2 is screwed as shown by an imaginary line in FIG. As a result, during rebar connection work, the entire coupler 2 is screwed into the male threaded portion 1c of either one of the reinforcing bars 1, and after the end surfaces of both reinforcing bars 1 and 1 are aligned, the coupler 2 is unscrewed while the other reinforcing bar 1 is unscrewed. It can be screwed into the male screw portion 1c. Therefore, it is not necessary to screw the reinforcing bar 1 while pulling it, and the workability of the on-site connection is improved. The cross-sectional shape of the thread groove of the male screw portion 1c may be triangular or trapezoidal.

A method for manufacturing the threaded reinforcing bar joint of the deformed reinforcing bar will be described with reference to FIG. Separately, the coupler 2 is prepared.
FIG. 3A shows a reinforcing bar 1 that is a deformed reinforcing bar as a material. The rebar 1 is cut into a desired length at a construction site or a factory (cutting process) (FIG. 3B). A round process is performed on a portion of the cut end of the rebar 1 in a length range for forming the male screw part 1c (round process) (FIG. 3C). As described above, this perfect circle processing is performed to a perfect circle having an outer diameter D5 (FIG. 1B) that is substantially eliminated such that the base end of the protrusion 1b composed of the node 1ba and the rib 1bb of the reinforcing bar 1 remains. This is a process of cutting, and the node portion 1ba becomes a portion 1ba 'having a low protruding height. The outer diameter D5 is slightly larger than the outer diameter D1 of the reinforcing bar main body 1a. Since there is a change in some sizes over threaded, the outside diameter D5 is different from the crest diameter D3 ₂ of the male screw portion 1c. The outer diameter D5 may be the same as or slightly smaller than the reinforcing bar main body outer diameter D1.
In this way, the male screw portion 1c (effective diameter D3 ₀ ) is formed by rolling on the portion of the reinforcing bar 1 that has been subjected to the perfect circle processing (male screw rolling process) (FIG. 3D). For formation of the male screw portion 1c by rolling, crest diameter D3 ₂ is the larger than the outer diameter D5 of a perfect circle processing, the effective diameter D3 ₀ is the outer diameter D5 of the perfect circle machining the composition flow. This rolling is performed by using a rolling tool (not shown) fitted on the outer periphery of the reinforcing bar 1 or a rolling facility (not shown) composed of a pair of opposing rolling rolls, for example, cold, warm, or Do it hot. More specifically, this rolling is, for example, a so-called three-point rolling process in which screw machining is performed at three points.

By rolling the male screw portion 1c in this way, the male screw portion 1c is hardened by work hardening. Further, the screw groove diameter D3 ₁ of the male screw portion 1c is thinner than the outer diameter D1 of the reinforcing bar body 1a, and becomes thicker than the outer diameter D1 of the reinforcing bar body 1a crest diameter D3 2 _'by swelling during rolling.
The perfect circle processing (FIG. 3C) is not necessarily performed.
Further, the length of the round processing and rolling of the male threaded portion 1c is made longer for length adjustment, and the male threaded portion 1c is cut at the location of the bar arrangement in accordance with the place of use, and used for the reinforcing bar joint. Anyway. This improves the workability.

According to the rebar joint of this structure, both the rebars 1 and 1 can be connected by screwing the male thread portions 1c and 1c of the pair of rebars 1 and 1 into the coupler 2, and simplification of the bar arrangement as in the case of a general rebar joint. The construction period can be shortened. The male screw portion 1c, thinner than the outer diameter D1 of the screw groove diameter D3 ₁ rebar body 1a, thicker than the outer diameter D1 of the crest diameter D3 ₂ rebar body 1a, also narrower than the maximum diameter D2. For this reason, the male threaded portion 1c can be formed as it is without subjecting the deformed reinforcing bar 1 as a raw material to a lower processing as it is or by performing a round processing by a perfect circle processing. Since the male threaded portion 1c is formed by threading the deformed reinforcing bar 1 without performing a large down-sizing such as increasing the diameter, the productivity is excellent. Since the screw groove diameter D3 ₁ of the male screw portion 1c narrow than the outer diameter D1 of the reinforcing bar body 1a, a scratch tension, etc. of the reinforcing bars in the joint portion but decrease in strength is feared, the hardness of the male screw portion 1c of the other Since it is harder than the part, it can compensate for a decrease in yield strength, and a sufficient yield strength can be obtained.

  The degree of hardening required to compensate for the decrease in yield strength due to the groove processing of the male screw portion 1c is sufficient for the work hardening obtained by rolling the male screw portion 1c. Therefore, if a male thread part is rolled to the deformed reinforcing bar 1 as it is, the hardness required for the male thread part 1c can also be obtained. For this reason, the process for exclusive use for raising the hardness of the external thread part 1c is unnecessary, and it is excellent also in productivity from this. If the coupler 2 is prepared, the subsequent work only needs to be performed by cutting the deformed reinforcing bar 1 and rolling the male screw portion 1c, and can also be performed at a construction site.

  4 to 6 show another embodiment of the present invention. This threaded reinforcing bar joint of the deformed reinforcing bar is the same as that of the threaded reinforcing bar joint of the first embodiment described above with reference to FIGS. 1 to 3, but is screwed into the male threaded portions 1 b and 1 b of the reinforcing bars 1 and 1. A pair of lock nuts 3, 3 are provided in contact with the end surfaces. The outer peripheral surface of the lock nut 3 may be circular or polygonal. In this embodiment, the length L of the male screw portion 1c is, for example, a length that allows the lock nut 3 and the coupler 2 to escape to one male screw portion 1c. This embodiment is the same as the first embodiment except for matters to be specifically described.

  In the case of the screw-type reinforcing bar joint having this configuration, the compressive force can be transmitted as follows. This will be described with reference to FIG. When a tensile force (indicated by a solid arrow in the figure) acts on the reinforcing bars 1 and 1 on both sides, the surface 1ca on the coupler 2 side of the thread of the male threaded part 1c of the reinforcing bar 1 causes the female threaded part 2a of the coupler 2 to A tensile force is transmitted to the surface 2aa on the screw cylinder center side in the screw thread. Therefore, the tensile force is directly transmitted from one reinforcing bar 1 to the nut 2 and is transmitted to the other reinforcing bar 1, and the meshing strength of the lock nut 3 does not affect the transmission of the tensile force. When a compressive force (indicated by a dashed arrow in the figure) acts on the reinforcing bars 1 and 1 on both sides, the female threaded part 3a of the lock nut 3 from the surface 1cb on the anti-coupler side of the thread of the male threaded part 1c of the reinforcing bar 1 Compressive force is transmitted to the surface 3aa on the screw cylinder side in the thread. The transmitted compressive force is transmitted to the coupler 2 from the contact surface between the lock nut 3 and the coupler 2. That is, the compressive force is transmitted from one reinforcing bar 1 to the other reinforcing bar 1 through the lock nut 3, the coupler 2, and the other lock nut 3.

  For this reason, the width C of the lock nut 3 is set to a length that can ensure the compression strength required for the reinforcing bar joint. It should be noted that the compression strength required for the reinforced joint is about half of the compression strength compared to the yield strength. For this reason, the fastening length of the lock nut 3 may be shorter than the fastening length to the coupler 2. From this point of view, each lock nut 3 has, for example, an axial width that can be screwed into at least two screw threads of the male screw portion 1c. In the case of this embodiment, the requirements of both tensile strength and compression strength can be satisfied as described above.

7 to 10 (A) show still another embodiment of the present invention. The threaded reinforcing bar joint of the deformed reinforcing bar is the same as the threaded reinforcing bar joint of the first embodiment described above with reference to FIGS. 1 to 3, but each reinforcing bar 1, 1 has a node 1 ba, but the longitudinal direction of the rib 1 bb etc. It consists of a deformed bar which does not have a ridge extending in the direction. The male screw portion 1c is formed of a rolled screw, and as a lower cut, the round processing is performed as shown in FIG. 9C, as described with reference to FIG. In this case, since there is no rib, basically, a round process is performed only on the node 1ba. If the reinforcing bar main body 1a of the reinforcing bar 1 is within the effective radius of the male screw portion 1c to be set, some roundness is corrected by rolling. The rib 1bb may be slightly generated in the rolling process, but in this case, the influence on the total cross-sectional area is small and no problem occurs.
This embodiment is the same as the first embodiment except for matters to be specifically described, and overlapping description is omitted. However, the dimensional examples are slightly different as follows.

This embodiment provides the following advantages compared to the first embodiment. Conventional deformed reinforcing bars called bamboo rebars are generally composed of a round shaft-shaped reinforcing bar body and joints / ribs, but the ribs also contribute to the tensile strength and account for about 4%. When the male threaded portion 1c is processed on the deformed reinforcing bar as in the first embodiment, the rib is interrupted at the thread groove portion, and the tensile strength that contributes to the cross-sectional area of the rib 1bb is reduced. Thereby, there exists a concern that the external thread part 1c may become a local weak part of tensile strength. In the first embodiment, since the male screw portion 1c is processed by rolling, the tensile strength is improved by work hardening, and the problem of strength reduction due to the formation of the male screw portion 1c does not substantially occur. It is desirable to ensure the strength.
The embodiment shown in FIGS. 7 to 10A further ensures the strength by slightly increasing the diameter of the reinforcing bar as follows. That is, a reinforcing bar having a large diameter of the reinforcing bar main body 1a is used corresponding to the cross-sectional area of the rib 1bb in the first embodiment.

A dimension example will be described with reference to FIG. In the first embodiment, for example, when the D19 rebar 1 is used, the diameter of the rebar main body 1a is 17.88 and the rib 1bb has a trapezoidal cross-sectional shape as shown in FIG. The upper base is 3.5, the lower base is 4.5, and the height is 1.4. The unit is mm. Units are the same or less, in the case of the area which is mm ^2.
Assuming that the cross-sectional area A ₀ , the rib cross-sectional area A ₁ , and the overall cross-sectional area A of the reinforcing bar main body 1a,
A ₀ = π (17.88) ² = 251.09
A ₁ = (3.5 + 4.5) 1.4 / 2 × 2≈11.2
A = A ₀ + A ₁ = 251.09 + 11.2 = 262.29
_{A 1 / A = 0.043 (4.3} %)
It is.
Therefore, in this embodiment, the diameter of the rebar main body 1a is 18.28 mm. in this case,
The cross-sectional area A _A of the reinforcing bar main body 1a is
A _A = π (18.28 / 2) ² = 262.45
It is.
Thus, the diameter of the reinforcing bar main body 1a is changed from 17.88 to 18.28, so that the rib is not formed and the reinforcing bar main body 1a is shifted to the reinforcing bar main body 1a. Thereby, the cross-sectional defect | deletion by screw processing is eliminated, and the performance as a joint further improves.

  11 and 12 show an example in which the lock nut 3 is used in the same manner as in the embodiment of FIGS. 4 to 6 using the reinforcing bar 1 in the embodiment of FIGS. 7 to 10A. In this embodiment, other matters are the same as those described above with reference to FIGS.

13 to 15 show a threaded reinforcing bar joint and a manufacturing method thereof according to another embodiment. This embodiment is the same as the first embodiment except for matters to be specifically described. In this embodiment, the reinforcing bar 1 has flat belt-like flat portions 4 over the entire length in the axial direction at two locations on the outer peripheral surface that are 180 ° apart from each other. As shown in FIG. 13B, the belt-like flat portion 4 has a shape in which a cross section perpendicular to the axial direction of the reinforcing bar 1 is a straight line that is a partial arc of a circle forming the outer peripheral surface of the screw body 1a. Since the belt-like flat part 4 has a planar shape, the width of the node 1ba of the reinforcing bar 1 is widened. The width d1 of the general portion (rebar main body 1a) of the belt-like flat portion 4 is equal to or larger than the base end width of the rib 1bb. The node portion 1ba is discontinuous at two locations in the circumferential direction by forming the belt-like flat portion 4 as described above.
FIG. 13C shows a modification of the reinforcing bar 1 and will be described later.

  A method for manufacturing the reinforcing bar 1 having the belt-like flat portion 4 will be described. First, as shown in FIG. 15, an intermediate reinforcing bar material W1 (FIG. 14A) having a node 1ba on the outer periphery of a round shaft-shaped reinforcing bar main body 1a is changed from a round shaft-shaped reinforcing bar material W0 to a pair of rolling rolls 11. , 11 is obtained by hot rolling (rolling process). At this time, the rib 1bb is inevitably generated over the entire length of the intermediate rebar material W1 due to the gap between the pair of rolling rolls 11 and 11.

The ribs 1bb on both side surfaces are scraped off from the heated intermediate rebar material W1 formed in the rolling process by the rib removing tool 14 installed at the subsequent stage of the rolling roll 11, and 180 ° apart from each other on the outer peripheral surface. It is processed into the thread processing material reinforcing bar W2 (FIG. 14B) having the belt-like flat portion 4 at two places (rib removing process). The rib removing tool 14 is a plate-like or lump-like tool having a straight tip, and if installed at a fixed position, the rib 1bb is scraped along with the feeding of the intermediate reinforcing bar material W1. The feeding is performed by, for example, a roll that rotationally drives a part of the guide rolls 12 and 13. These guide rolls 12 and 13 are arranged along the rebar feed direction before and after the rolling roll 11.
The threading material rebar W2 having the belt-like flat portion 4 is cut to a certain length with a straight material, but there are cases where the fine material is manufactured as a coil-shaped material.

The long threaded material rebar W2 prepared in this way is used by cutting it to an arbitrary length as shown in FIG. 14C, for example, at the site of the bar arrangement or at the factory (cutting process). .
The cut circular material rebar W2 is subjected to the above-described circular processing, so that the node portion 1ba becomes a portion 1ba 'having a low protruding height as shown in FIG. The broken line in the figure shows the node portion 1ba in the state before processing the perfect circle in this portion 1ba '.
In the same way as described in the first embodiment, the male threaded portion 1c is processed for the length range of the threaded material rebar W2 that has been subjected to the circular processing in the same manner as described in the first embodiment (male thread rolling process). .

  In the case of this configuration, the reinforcing bar 1 having the male screw portion 1c has the belt-like flat portion 4 and does not have a protruding portion such as a rib continuing in the longitudinal direction. Therefore, compared with what was screw-processed to the deformed reinforcing bar which has the said rib, the cross-sectional area by the cross-sectional defect | deletion accompanying a perfect circle process or a screw process in the formation part of the external thread part 1c in the reinforcing bar 1 and the general part without the external thread part 1c The difference is small and the difference in yield strength is small. For this reason, a rebar joint does not become a problem as a local weak part of a rebar practically. By setting the reinforcing bar to have a large diameter corresponding to the cross-sectional area of the rib, even if there is no rib, the same proof strength as that of the reinforcing bar with the rib is secured. For example, the cross-sectional area of the rib 1bb is about 4% of the total cross-sectional area, and by using a correspondingly large diameter reinforcing bar, the same proof strength as that of the reinforcing bar with the rib is ensured.

  When the male screw portion 1c is a rolled screw as in this embodiment, a cross-sectional defect such as cutting does not occur, and the other part of the entire rebar circumference has a large diameter due to plastic flow. There is little decline. Moreover, if it is a rolled screw, plastic hardening occurs in the male screw rolling process, and the yield strength is improved. Therefore, in practice, by setting the thickness and the reinforcing bar 1 so as to compensate for a part of the cross-sectional area difference of about 4%, the proof strength equivalent to that of the reinforcing bar with ribs is ensured.

Also, in the manufacturing process, when the reinforcing bar 1 having the node portion 1ba and the male screw portion 1c is manufactured, even if the rib 1bb occurs when the node portion 1ba is formed by rolling, the rib-shaped flat portion is removed by removing the rib 1bb. The reinforcing bar 1 with the external thread 1c can be manufactured using a deformed reinforcing bar by general rolling as a raw material.
The removal of the rib 1bb can be obtained by forming the belt-like flat portion 4 by scraping the rib 1bb from the heated intermediate rebar material W1 formed in the rolling process for obtaining the node 1ba. A process such as cutting is unnecessary, and it can be easily and efficiently removed.

In this embodiment, the strip-like flat portion 4 is provided in the reinforcing bar 1. However, as shown in FIG. 13C, for example, a reinforcing bar that does not have the rib 1bb is used as in this embodiment. Similarly, the difference in yield strength between the portion where the male screw portion 1c is formed in the reinforcing bar 1 and the general portion without the male screw portion 1c can be reduced. If only the rib is eliminated, that is, if there is no projecting portion extending along the longitudinal direction, there is no change in the cross-sectional area before and after the rolling of the screw, and there is no problem even if the node 1ba extends. In the reinforcing bar 1 in the example of FIG. 13C, the reinforcing bar main body 1a is a perfect circle over the entire circumference, and the node part 1ba has two discontinuous parts 1baa in the circumferential direction. When the strip-shaped flat portion is not formed only by eliminating the ribs in the figure, the rolling equipment has a special specification for forming the node 1ba by rolling, but the rib removing process by scraping is unnecessary.
In the case where the reinforcing bar 1 provided with the belt-like flat portion 4 is used, or when the reinforcing bar not having the rib 1bb is used as shown in FIG. It may be provided.

  Further, in each of the above embodiments, the reinforcing bars 1 and 1 on both sides have the same configuration, but the reinforcing bars 1 and 1 on both sides may not have the same diameter, and either one of the reinforcing bars 1 is an example shown in FIG. Instead of a deformed reinforcing bar, a round shaft may be used. In this example, a reinforcing bar 1A that is one size larger is used. By using the reinforcing bar 1A that is one size larger, a decrease in the rigidity of the male screw portion 1c is avoided.

  FIGS. 17 and 18 show an example in which a diameter-enlarged head 6 for fixing force application is formed by attaching a diameter-enlarged head imparting component 61 to the male threaded portion 1c of the reinforcing bar 1 processed from the male threaded portion 1c through its screw hole 61a. It is. The male screw portion 1c of the reinforcing bar 1 in the figure may be formed for a reinforcing bar joint, or may be formed short for mounting the enlarged diameter head imparting component 61. Further, one end of the reinforcing bar 1 may be connected to another reinforcing bar with the screw-type reinforcing bar joint of FIG. The diameter-enlarged head imparting component 61 is a plate having a screw hole 61a, and the outer peripheral shape may be a circle as shown in FIG. 18A or a rectangle as shown in FIG. good.

In general, the end portion of the reinforcing bar 1 is formed in a U-shape or L in order to secure a fixing force in a pillar when, for example, a reinforcing bar of a concrete part that becomes a beam is embedded in a concrete part that becomes a column. It is often bent and embedded in a letter shape. However, if there are many such bent portions of the reinforcing bars, the arrangement of the bars in the column becomes complicated. Therefore, an enlarged head having an enlarged diameter is formed at the end of the reinforcing bar, and fixing force is secured instead of a U-shaped or L-shaped bent portion. Since the part is manufactured by plastically deforming the end of the reinforcing bar by high-frequency induction or the like, equipment and labor are required in the manufacturing process.
In response to such a problem, when the enlarged head portion 61 shown in FIGS. 17 and 18 is screwed to form the enlarged head portion 6, no special equipment is required, and it can be easily expanded without much effort. A radial head 6 can be formed.
In the embodiment shown in FIGS. 17 and 18, the reinforcing bars 1 shown in FIGS. 7 and 13 may be used.

  As mentioned above, although the form for implementing this invention based on embodiment was demonstrated, embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1, 1A ... Reinforcing bar 1a ... Reinforcing bar main body 1b ... Projection 1ba ... Node 1bb ... Rib 1c ... Male screw part 2 ... Coupler 2a ... Female screw part 3 ... Lock nut 4 ... Strip-like flat part D1 ... Outer diameter D2 of reinforcing bar main body ... Maximum Diameter D3 ₀ ... Screw effective diameter D3 ₁ ... Screw groove diameter D3 ₂ , D3 ₂ '... Screw thread diameter

Claims (6)

A pair of reinforcing bars are provided at the ends of both reinforcing bars and are connected by a threaded cylindrical coupler that is threadedly engaged with the male threaded portion. One or both reinforcing bars of the pair are long on the outer periphery of the round shaft-shaped reinforcing bar body. at intervals in the longitudinal direction have a plurality of knuckles, and in threaded rebar joint deformed bar is deformed bars having a ridge extending in a longitudinal direction,
Wherein the end of one or both of the reinforcing bar, the screw groove diameter having a thin male threaded portion than the reinforcing bar body, the male screw portion is thicker portions plurality of locations is a crest diameter of the width corresponding to the knuckles The remainder is a portion with a small thread diameter except for the same circumferential direction as the ridge, the thread groove diameters of both portions are the same, and the thread groove depth of the portion with the thin thread diameter is the same. , 70% or more of the thread groove depth of the thick part of the thread diameter, and the thread diameter of the thick part of the thread diameter is thicker than the rebar main body of the rebar and includes the ridge. A deformed reinforcing bar comprising a cylindrical coupler that is thin, has a hardness of the male screw part that is harder than other parts of the reinforcing bar or has a higher tensile strength, and is screwed into the male screw part of the two reinforcing bars. Screw rebar joint. In a threaded rebar joint of a deformed rebar in which a pair of rebars are provided at the ends of both rebars and are connected by a threaded cylindrical coupler that is screwed into a male thread, and one or both of the rebars are deformed rebars ,
The one or both reinforcing bars are deformed reinforcing bars having a plurality of nodes spaced apart in the longitudinal direction without having protrusions extending in the longitudinal direction on the outer circumference of the round shaft-shaped reinforcing bar body,
Wherein the end of one or both of the reinforcing bar, the screw groove diameter having a thin male threaded portion than the reinforcing bar body, the male screw portion is thicker portions plurality of locations is a crest diameter of the width corresponding to the knuckles The remainder is a portion with a thin thread diameter, the thread groove diameters of both portions are the same, and the thread groove depth of the thin thread diameter portion is the thread groove depth of the thick thread diameter portion. The thread diameter of the portion having a large thread diameter is 70% thicker than the rebar main body of the rebar and smaller than the maximum diameter including the protrusions, and the hardness of the male screw portion is the rebar. A screw-type reinforcing bar joint for deformed reinforcing bars comprising a cylindrical coupler that is harder or has a higher tensile strength than the other parts and that is screwed into the male threaded portions of both reinforcing bars.   The threaded reinforcing bar joint of the deformed reinforcing bar according to claim 2, wherein the one or both reinforcing bars have an axial cross section perpendicular to an axial direction at two locations 180 ° apart from each other on the outer peripheral surface. A threaded reinforcing bar joint of a deformed bar having a belt-like flat portion that is a straight line that forms a partial arc of a circle formed over the entire length in the axial direction.   The deformed reinforcing bar threaded reinforcing bar joint according to any one of claims 1 to 3, wherein the deformed reinforcing bar has a lock nut that is screwed into the male thread portion of the reinforcing bar and abuts against an end face of the coupler. Threaded rebar joint.   5. A method of manufacturing a threaded reinforcing bar joint of a deformed reinforcing bar according to claim 1, wherein the deformed reinforcing bar having a protrusion on the outer periphery of the reinforcing bar main body is cut to an arbitrary length. The process, a male thread rolling process in which the male thread part is processed by rolling without subjecting the end of the cut reinforcing bar to a diameter expansion process, and the male thread part of the pair of reinforcing bars in which the male thread part is machined. A method of manufacturing a threaded reinforcing bar joint of a deformed reinforcing bar including a step of preparing a coupler to be deformed.   In the manufacturing method of the threaded reinforcing bar joint of the deformed reinforcing bar according to claim 5, the outer diameter of the extent that the protrusion is substantially eliminated in the length range in which the male screw part is formed at the end of the reinforcing bar after the cutting process. The manufacturing method of the screw-type reinforcing bar joint of the deformed bar which carries out the rolling after this round processing process.

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