JP6807779B2 - coupler - Google Patents

Description

The present invention relates to a coupler for connecting and fixing the ends of the leading side reinforcing bar and the connecting side reinforcing bar, and a casting method thereof.

In order to connect deformed steel bars that are reinforcing materials for concrete structures for civil engineering and construction, deformed steel bars such as threaded reinforcing bars with flat surfaces and threaded joints on the outer circumference and bamboo joints with flat surfaces and bamboo joints formed on the outer circumference. A coupler that can be fitted to the is used.

In the jointing method of a concrete structure, the end of the connecting side reinforcing bar is inserted into the coupler in which the leading side reinforcing bar is integrated, and the connecting side reinforcing bar is screwed into the coupler to lead through the coupler. The side reinforcing bar and the connecting side reinforcing bar are joined.

In Patent Document 1, about half of the coupler is fitted to the leading reinforcing bar, torque is introduced into the lock nut to fix the leading reinforcing bar to the coupler, and then the connecting side reinforcing bar is fitted to the coupler and joined. It is disclosed that torque is introduced in a state where the side reinforcing bar is pressed against the end face of the leading side reinforcing bar.

Patent Document 2 discloses that a leading side reinforcing bar is frictionally pressed against a bag-shaped coupler, a metric screw is frictionally pressed against a connecting side reinforcing bar, and a male screw is screwed into a coupler to introduce torque. Has been done.

In Patent Document 3, a leading side reinforcing bar is friction-welded to a bag-shaped coupler, a male metric screw is welded to the end of the connecting side reinforcing bar, and the male screw is screwed into the coupler to introduce torque. It is disclosed.

Japanese Unexamined Patent Publication No. 9-209504 Japanese Unexamined Patent Publication No. 7-224495 Japanese Unexamined Patent Publication No. 8-261216

However, in the joint structure described in Patent Document 1 as described above, as the diameter of the reinforcing bar and the diameter of the coupler become larger, the joint performance cannot be ensured unless a high torque is introduced into the lock nut on the preceding side. There was a problem that a working environment was required.

In addition, when checking the tightening of the lock nut and retightening the lock nut, when torque is introduced to the lock nut, the operator visually checks whether the mark that is applied so as to straddle the end of the coupler and the end of the lock nut is misaligned. There is a problem that the tightening work of the lock nut is complicated because it is performed in.

In order to omit the tightening work and tightening confirmation of the lock nut, it is conceivable to form the coupler in a bag shape to reduce the number of lock nuts installed as in the joint structure described in Patent Documents 2 and 3. However, there is a problem that the coupler cannot be formed into a bag shape when cutting with a tap in a coarsely shaped node having a large pitch such as a threaded reinforcing bar.

Further, in the joint structure described in Patent Document 2 as described above, it is necessary to rotate the male screw at high speed when frictionally pressing the male screw and the leading reinforcing bar, but the number of parts increases and a plurality of frictional pressure welding steps are performed. There is a problem that the manufacturing work becomes complicated because it has to be performed repeatedly.

Further, in the joint structure described in Patent Document 3 as described above, when the male screw and the leading reinforcing bar are welded, the reinforcing bar has a large amount of carbon and is highly hardenable, so that quench hardening occurs after welding to ensure strength. In order to do so, there is a problem that preheating and post-heat treatment are required.

Therefore, the present invention has been made in view of such conventional problems, and an object of the present invention is to provide a coupler capable of easily and firmly joining the leading side reinforcing bar and the connecting side reinforcing bar.

The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 is a coupler for connecting and fixing the ends of the leading side reinforcing bar and the connecting side reinforcing bar, and is a coupler made of a casting. An insertion hole formed in the main body and the coupler main body from the end surface of the joint side toward the leading side and into which the joint side reinforcing bar can be inserted, and an outer periphery on the leading side of the coupler main body in contact with the coupler main body. Provided is a coupler comprising an intermediate member which is fixed so as to be held and whose end portion protruding from the leading end surface of the coupler body is frictionally pressed against the leading reinforcing bar.

According to this configuration, the intermediate member is fixed to the tip side of the coupler body, and the work of introducing torque to the leading side reinforcing bar can be omitted by frictionally pressing the intermediate member and the tip side reinforcing bar, and the number of parts is small. The side reinforcing bar and the joint side reinforcing bar can be easily joined.

The invention according to claim 2 provides a coupler in which a retaining protrusion is formed on the outer periphery of the intermediate member, in addition to the configuration of the invention according to claim 1.

According to this configuration, the retaining protrusions provided around the outer periphery of the intermediate member engage with the coupler body to prevent the intermediate member from coming off the coupler body, so that the intermediate member and the coupler body can be easily separated. It can be formed integrally.

The invention according to claim 3 provides a coupler in which the retaining protrusion of the intermediate member is spirally formed along the longitudinal direction of the coupler, in addition to the configuration of the invention according to claim 2.

According to this configuration, the intermediate member is firmly prevented from coming off by the coupler main body by engaging the retaining protrusions spirally formed on the outer circumference of the intermediate member with the coupler main body at a plurality of places in the longitudinal direction. , The intermediate member and the coupler body can be easily integrally formed.

In the present invention, the intermediate member is fixed to the tip side of the coupler, and the work of introducing torque to the leading side reinforcing bar can be omitted by frictionally pressing the intermediate member and the tip side reinforcing bar, and the leading side reinforcing bar can be combined with a small number of parts. It can be easily joined to the connecting side reinforcing bar.

The schematic diagram which shows the state which connected and fixed the leading side reinforcing bar and the connecting side reinforcing bar by using the coupler which concerns on 1st Example of this invention. Front view and vertical sectional view of the coupler. The schematic diagram which shows the process of manufacturing the core used for casting of the coupler of FIG. The schematic diagram which shows the process of casting the coupler of FIG. The schematic diagram which shows the procedure of friction pressure welding of the leading side reinforcing bar to an intermediate member. The schematic diagram which shows the procedure of screwing a connecting side reinforcing bar into an intermediate member.

The present invention is a coupler for connecting and fixing the ends of the leading side reinforcing bar and the connecting side reinforcing bar in order to achieve the object of providing a coupler capable of easily and firmly joining the leading side reinforcing bar and the connecting side reinforcing bar. The coupler body is made of cast metal, an insertion hole is formed in the coupler body from the end face of the joint side toward the leading side, and a reinforcing bar on the joint side can be inserted, and the outer periphery is the leading side of the coupler body. This was realized by providing an intermediate member that is fixed so as to be in contact with and held in contact with the coupler body, and the end portion projecting from the preceding end surface of the coupler body is frictionally pressed against the leading reinforcing bar.

Hereinafter, the coupler 1 according to an embodiment of the present invention will be described with reference to the drawings. In each of the following examples, when the number, numerical value, quantity, range, etc. of the components are referred to, the specific number is not specified unless it is clearly specified or the number is clearly limited in principle. It is not limited to, and may be more than or less than a specific number.

In addition, when referring to the shape and positional relationship of components, etc., unless otherwise specified or when it is considered that this is not the case in principle, those that are substantially similar to or similar to the shape, etc. shall be used. Including.

In addition, the drawings may be exaggerated by enlarging the characteristic parts in order to make the features easy to understand, and the dimensional ratios and the like of the components are not always the same as the actual ones. Further, in the cross-sectional view, hatching of some components may be omitted in order to make the cross-sectional structure of the components easy to understand.

FIG. 1 is a cross-sectional view showing a state in which the leading side reinforcing bar 2 and the connecting side reinforcing bar 3 are connected and fixed by the coupler 1. FIG. 2A is a front view showing the coupler 1 of the present invention, and FIG. 2B is a vertical sectional view of FIG. 2A.

The coupler 1 joins the ends of the leading reinforcing bar 2 and the connecting side reinforcing bar 3 to each other. That is, the coupler 1 and the leading side reinforcing bar 2 are embedded horizontally or vertically in the concrete, and the connecting side reinforcing bar 3 is inserted into the coupler 1 and screwed into the coupler 1 to form the leading side reinforcing bar 2 and the leading side reinforcing bar 2. The connecting side reinforcing bar 3 is joined. The connecting side reinforcing bar 3 is a reinforcing material protruding from an end portion of a concrete structure for civil engineering and construction.

The coupler 1 includes a coupler main body 11 extended along the longitudinal direction L, an insertion hole 12 provided in the coupler main body 11, and an intermediate member 13 embedded in the coupler main body 11.

The coupler body 11 is made of, for example, mild steel or spheroidal graphite cast iron. The coupler body 11 is formed in a hexagonal tubular shape extending along the longitudinal direction L. The cross-sectional shape of the coupler body 11 is not limited to the hexagonal shape, and may be, for example, a circular shape.

The insertion hole 12 is formed from the end surface 1a on the joint side of the coupler main body 11 toward the leading side. That is, the insertion hole 12 is open only on the joint side, and the leading side is closed by the intermediate member 13. That is, the coupler 1 is formed in a bag shape having an opening in the joint end surface 1a.

A node 12a is formed on the inner circumference of the insertion hole 12. The knot portion 12a is formed in a shape that can be fitted to the joint reinforcing bar 3. Specifically, the knots 12a are arranged in a row at predetermined intervals along the longitudinal direction L of the coupler main body 11. The knot portion 12a is formed so as to have a spirally formed ridge formed in the insertion hole 12 cut out along the longitudinal direction L. The rows of the knots 12a are two rows and are arranged so as to face each other. Although the knot portion 12a is formed in a threaded knot shape, it may be formed in a so-called bamboo knot shape.

The intermediate member 13 is a reinforcing bar that is shorter and smaller than the coupler 1. The intermediate member 13 has a connecting end portion 13a projecting from the leading end surface 1b of the coupler main body 11 and is fixed to the leading side of the coupler main body 11. The total length of the intermediate member 13 is set to be about 40 to 50% of the total length of the coupler main body 11. Further, the intermediate member 13 is exposed from the coupler main body 11 by several tens of mm on the leading side. The intermediate member 13 is made of, for example, soft iron. As the intermediate member 13, it is preferable to use scraps generated when cutting the reinforcing bar.

A retaining protrusion 13b is formed on the outer periphery of the intermediate member 13. The retaining protrusion 13b is formed in a spiral shape along the longitudinal direction L. By projecting the retaining convex portion 13b toward the outside in the radial direction R orthogonal to the longitudinal direction L, the retaining convex portion 13b can resist the external force of pulling the intermediate member 13 from the coupler main body 11. it can. The height of the retaining convex portion 13b in the radial direction R can be arbitrarily changed according to the magnitude of the assumed external force.

The leading side reinforcing bar 2 is a threaded reinforcing bar, and a flat surface 2a and a threaded joint 2b are provided on the outer periphery thereof. The leading side reinforcing bar 2 is fixed to the coupler 1 by frictionally pressing the end face of the leading side reinforcing bar 2 to the intermediate member 13. The leading side reinforcing bar 2 may be a bamboo joint reinforcing bar in addition to the screw joint reinforcing bar.

The connecting side reinforcing bar 3 is a threaded reinforcing bar, and a flat surface 3a and a threaded joint 3b are provided on the outer periphery thereof. The connecting side reinforcing bar 3 is inserted into the insertion hole 12 and screwed into the knot portion 12a, so that the leading side reinforcing bar 2 and the connecting side reinforcing bar 3 are integrally connected and fixed via the coupler 1. .. The jointing side reinforcing bar 3 may be a bamboo joint reinforcing bar in addition to the screw joint reinforcing bar.

Next, the step of casting the coupler 1 will be described with reference to the drawings. FIG. 3 is a schematic view showing a process of manufacturing the core 5 used for casting the coupler 1. FIG. 4 is a schematic view showing a process of casting the coupler 1.

The casting process of the coupler 1 mainly consists of core production, mold assembly, molten iron pouring, solidification / cooling, mold disassembly, and finishing.

[Core production]
The core 5 is formed by combining a pair of core pieces 5a and 5b. First, a procedure for manufacturing the core piece 5a including the connection end portion 13a will be described. As shown in FIG. 3A, a pair of wooden molds 4a are prepared. The wooden mold 4a is provided with through holes 4b that penetrate the upper and lower parts. The through hole 4b is formed by communicating the lower opening 4c and the upper opening 4d. As shown in FIG. 3B, the intermediate member 13 is inserted into the through hole 4b so as to close the lower opening 4c. Next, as shown in FIG. 3C, the core sand is filled into the through hole 4b from the upper opening 4d. After the core sand in the through hole 4b is hardened, as shown in FIG. 3D, a pair of wooden molds 4a are punched out to obtain a core piece 5a corresponding to the shape of the through hole 4b. A support portion 5c is provided at the end of the core piece 5a.

Next, a procedure for manufacturing the core piece 5b, which is combined with the core piece 5a to form the core 5, will be described. As shown in FIG. 3 (e), a pair of wooden patterns 4e are prepared. The wooden pattern 4e is provided with through holes 4f that penetrate the upper and lower parts. The through hole 4f is formed by communicating the lower opening 4g and the upper opening 4h. Next, as shown in FIG. 3 (f), the core sand is filled into the through hole 4f from the upper opening 4h. After the core sand in the through hole 4f is hardened, as shown in FIG. 3 (g), a pair of wooden molds 4e are punched out to obtain a core piece 5b corresponding to the shape of the through hole 4f. A support portion 5d is provided at the end of the core piece 5b. It does not matter which of the core pieces 5a and 5b is manufactured first.

[Mold assembly]
As shown in FIG. 4A, a lower mold (sand mold) 6a is prepared, and as shown in FIG. 4B, the core 5 is placed on the lower mold (sand mold) 6a. Next, as shown in FIG. 4C, the core 5 is covered with the upper mold (sand mold) 6b, the main mold 6 is molded, and the mold 7 is assembled. Specifically, a substantially cylindrical recess 6c larger than the core 5 is formed inside the main mold 6, and the core 5 is housed in the recess 6c. Further, the support portions 5c and 5d are sandwiched between the lower mold 6a and the upper mold 6b and supported. The core 5 and the intermediate member 13 are not limited to those integrated in advance, and when the core 5 and the intermediate member 13 are manufactured separately and the mold 7 is assembled, the intermediate member 13 is inside the core 5. It does not matter if it is stored in.

[Melted iron pouring]
As shown in FIG. 4D, molten iron (ductile cast iron) is poured into the mold 7 from the sprue 7a of the mold 7. Since the molten iron is filled in the gap between the core 5 and the main mold 6, the portion of the intermediate member 13 that crosses the gap between the core 5 and the main mold 6 is wrapped in the molten iron.

[Coagulation / cooling]
When the mold 7 is filled with molten iron, the pouring of the molten iron is stopped to solidify and cool the molten iron.

[Molding]
As shown in FIG. 4E, when the molten iron in the mold 7 is cooled, the mold 7 is destroyed and the coupler 1 is taken out. The gap between the core 5 and the main mold 6 corresponds to the coupler main body 11, and the core sand portion of the core 5 corresponds to the insertion hole 12, and the intermediate member 13 embedded in the support portion 5c. The end corresponds to the connection end 13a. Further, the boundary between the intermediate member 13 and the coupler body 11 after cooling is not welded, and the coupler body 11 is formed so as to follow the shape of the retaining protrusion 13b formed on the outer periphery of the intermediate member 13. There is. That is, the retaining convex portion 13b engages with the coupler 1 main body 11 to be firmly prevented from coming off, so that the intermediate member 13 and the coupler main body 11 are integrally formed.

[Finishing]
Unnecessary parts such as the sprue 7a and the runner 7b adhering to the coupler 1 are cut with a cutter, and the surface of the coupler 1 is cast and finished with a grinder. After that, the coupler 1 is obtained by performing heat treatment and shot blast polishing.

Next, a procedure for frictionally pressing the leading reinforcing bar 2 to the intermediate member 13 will be described with reference to FIG.

First, as shown in FIG. 5A, the outer circumference of the coupler main body 11 is gripped by the chuck 8. Further, the intermediate member 13 and the leading side reinforcing bar 2 are arranged coaxially, and the end surface 13c of the intermediate member 13 and the end surface 2a of the leading side reinforcing bar 2 are brought into contact with each other.

Next, as shown in FIG. 5B, the coupler main body 11 is rotated at high speed, and the leading reinforcing bar 2 is pressed toward the intermediate member 13. A high temperature layer is formed between the intermediate member 13 and the leading reinforcing bar 2 by frictional heat, and a part of the intermediate member 13 and a part of the leading reinforcing bar 2 are discharged as burrs B.

Then, as shown in FIG. 5C, the rotation of the coupler main body 11 is suddenly stopped, and the leading reinforcing bar 2 is further pressurized toward the intermediate member 13, so that the intermediate member 13 and the leading reinforcing bar 2 rub against each other. It is pressed.

Next, a procedure for connecting the leading side reinforcing bar 2 and the connecting side reinforcing bar 3 using the coupler 1 will be described with reference to FIG.

First, as shown in FIG. 6A, the coupler 1 and the leading reinforcing bar 2 are horizontally embedded in the concrete. The coupler 1 may be embedded vertically in concrete.

Next, as shown in FIG. 6B, the grout material is injected into the insertion hole 12.

Then, as shown in FIG. 6C, the connecting side reinforcing bar 3 is fitted to the node portion 12a of the coupler 1. When the connecting side reinforcing bar 3 is inserted into the coupler 1, the tip of the connecting side reinforcing bar 3 is an intermediate member 13 with the flat surface 3a of the connecting side reinforcing bar 3 facing the knot portion 12a with a gap. Slide until it touches. At this time, the grout injected into the insertion hole 12 is filled in the gap between the coupler 1 and the connecting side reinforcing bar 3. Then, as the grout filled in the gap is hardened, the coupler 1 and the connecting side reinforcing bar 3 are firmly fixed. The fitting distance between the coupler 1 and the connecting side reinforcing bar 3 is preferably about 50 to 60% of the total length of the coupler 1.

In addition to the grout method in which the joint reinforcing bar 3 is fixed to the coupler 1 by using a grout as described above, a so-called torque method may be used. In the torque method, after the tip of the connecting side reinforcing bar 3 is pressed against the intermediate member 13, the connecting side reinforcing bar 3 is rotated to screw the threaded joint 3b and the joint portion 12a of the connecting side reinforcing bar 3. As a result, the coupler 1 and the connecting side reinforcing bar 3 can be firmly connected.

In this way, in the coupler 1 according to the present embodiment, the intermediate member 13 is fixed to the tip side of the coupler 1, and the intermediate member 13 and the tip side reinforcing bar 2 are frictionally pressed to apply torque to the leading side reinforcing bar 2. The work of introducing can be omitted, and the leading side reinforcing bar 2 and the connecting side reinforcing bar 3 can be easily joined with a small number of parts.

Further, the intermediate member 13 is firmly prevented from coming off by the coupler main body 11 by engaging the retaining convex portions 13b spirally formed on the outer periphery of the intermediate member 13 with the coupler main body 11 at a plurality of places in the longitudinal direction L. Therefore, the coupler main body 11 and the intermediate member 13 can be easily integrally formed.

The coupler 1 can be obtained in a resource-saving manner by reusing the scraps generated when cutting the reinforcing bar in the intermediate member 13.

It should be noted that the present invention can be modified in various ways as long as it does not deviate from the spirit of the present invention, and it is natural that the present invention extends to the modified ones.

1 ... Coupler 1a ... Joint side end face 1b ... Leading side end face 11 ... Coupler body 12 ... Insertion hole 12a ... Knot 13 ... Intermediate member 13a ... Connection end Part 13b ・ ・ ・ Convex part to prevent slipping out 2 ・ ・ ・ Leading side reinforcing bar 2a ・ ・ ・ Flat surface (of leading side reinforcing bar) 2b ・ ・ ・ Screw joint (of leading side reinforcing bar) 3 ・ ・ ・ Joint side reinforcing bar 3a ・・ ・ Flat surface (of the rebar on the joint side) 3b ・ ・ ・ Screw joint L ・ ・ ・ Longitudinal direction R ・ ・ ・ Radial direction

Claims (3)

A coupler that connects and fixes the ends of the leading side reinforcing bar and the connecting side reinforcing bar.
With a caster coupler body
An insertion hole formed in the coupler body from the end face of the joint side toward the leading side and into which the joint side reinforcing bar can be inserted.
An intermediate member whose outer circumference is fixed so as to be in contact with and held on the leading side of the coupler main body, and the end portion protruding from the leading end surface of the coupler main body is frictionally pressed against the leading reinforcing bar. ,
A coupler characterized by being equipped with. The coupler according to claim 1, wherein the intermediate member has a retaining convex portion formed on the outer periphery thereof. The coupler according to claim 2, wherein the retaining protrusion of the intermediate member is formed in a spiral shape along the longitudinal direction of the coupler.