JP5740629B2 - Rebar mechanical joints - Google Patents

Description

  The present invention relates to a mechanical joint for a reinforcing bar in which a spring is pressure-bonded to an inner peripheral surface of a sleeve.

Conventionally, mechanical joints used to join reinforcing bars are often uneven on the outer and inner peripheral surfaces of the sleeve in order to increase the adhesion between the sleeve and the filler and to strengthen the force against the tensile force of the reinforcing bars. Is formed.
Regarding the formation of irregularities, a method of forming irregularities on the sleeve by plastic deformation is provided, and a spiral wound spring is inserted into the sleeve and integrated to form the shape formed by the spring and the sleeve. Techniques for making irregularities are provided.

  However, if the spring is simply inserted into the sleeve, the integration of the sleeve and the spring is weak, and when the reinforcing bar receives a tensile force in the axial direction from the outside, the spring will come off. Therefore, in order to enhance the integration of the sleeve and the spring, a groove corresponding to the shape of the spring is formed in the sleeve.

  In this respect, Patent Document 1 discloses a joint in which thread irregularities for a coil spring are formed on both surfaces of a metal cylindrical material, the coil spring is inserted into the thread irregularities, and the coil spring is fixed, and a manufacturing method thereof. Proposed. Furthermore, in Patent Document 1, a joint in which a load is applied by a pressing member from the outside of a metal cylindrical material into which a coil spring is inserted to be plastically deformed and screw thread irregularities are formed on both surfaces of the metal cylindrical material, and a manufacturing method thereof Has been proposed.

JP 2003-184222 A

According to the joint described in Patent Document 1, the tensile force acting on the reinforcing bar is resisted by the coil spring inserted into the metal cylindrical material.
However, a load is applied to a portion of the outer peripheral surface of the metal cylindrical material where the coil spring does not contact, and the portion is recessed inward in the radial direction, thereby forming a recess into which the coil spring is fitted. Therefore, the manufacturing process is complicated, and the metal cylindrical member is in a state where a plastically deformed portion and a portion that is not plastically deformed coexist, and the strength of the metal cylindrical member itself is not sufficient.

  Accordingly, an object of the present invention is to provide a mechanical joint that can resist a tensile force acting on a reinforcing bar by a spring inserted into a sleeve, and that is easy to manufacture and has high strength.

  In order to achieve the above object, a mechanical joint for reinforcing bars according to the present invention is a mechanical joint for joining two reinforcing bars, and has a cylindrical sleeve formed with an insertion hole opened at both ends, and an elastic force. And a spring in which a linear member is spirally wound, and the sleeve is reduced in diameter by plastic deformation over the entire surface in a state where the spring is inserted into the insertion hole, The spring is elastically deformed in the radial direction and the axial direction as the sleeve is reduced in diameter, and is crimped to the inner wall of the through hole of the sleeve. Two rebars are inserted in the circumference, and the insertion hole is filled with a filler, and the two rebars are joined.

Plastic deformation is, for example, by swaging.
The filler is used to fix the reinforcing bar and the mechanical joint. For example, an inorganic material such as cement milk or mortar, or an organic material such as epoxy resin can be used.
In addition, since the filler enters the penetration hole into which the reinforcing bar is inserted along the spiral shape of the spring, the filling material can be filled without a gap.

  The two reinforcing bars may be deformed reinforcing bars.

  Further, the reinforcing bar joining method according to another aspect of the present invention includes a cylindrical sleeve formed with an insertion hole having both ends opened, and a spring having an elastic force and winding a linear member in a spiral shape. And a method of joining two reinforcing bars by a mechanical joint provided with the spring inserted into the insertion hole of the sleeve, and by reducing the diameter by plastically deforming the sleeve. A step of pressing the spring against the inner wall of the through hole of the sleeve, a step of inserting two reinforcing bars into the inner periphery of the spring pressed into the through hole, and a filling material into the through hole. And a process.

  ADVANTAGE OF THE INVENTION According to this invention, the mechanical coupling which can resist the tensile force which acts on a reinforcing bar with the spring inserted in the sleeve can be manufactured in a simple process. Further, since the entire sleeve is plastically deformed, a mechanical joint having high strength can be provided.

It is a partial sectional view showing the mechanical joint concerning the embodiment of the present invention. It is a disassembled perspective view of the mechanical coupling which concerns on this embodiment. It is a perspective view which shows a mode that a sleeve is plastically deformed in the manufacturing process of the mechanical coupling which concerns on this embodiment. It is a partial sectional view showing typically use and an operation of a mechanical joint concerning this embodiment.

Next, a reinforcing bar mechanical joint according to an embodiment of the present invention will be described with reference to the drawings.
The mechanical joint 1 according to the present embodiment includes a sleeve 2 and a spring 3 as shown in FIG.
As will be described later, the sleeve 2 is pressed from the outer peripheral surface to reduce the diameter in a state in which the spring 3 is inserted into the through-hole 21, so that the spring 3 has an inner peripheral surface of the through-hole 21. Crimped to.

  As shown in FIG. 2, the sleeve 2 has a cylindrical shape, and has a through-hole 21 that is open at both ends. The sleeve 2 may be appropriately provided with an inlet for injecting a filler such as mortar, a bolt hole into which a fixing bolt for fixing the reinforcing bar in the sleeve 2 is screwed, or the like.

As shown in FIG. 2, the spring 3 is formed by winding a linear member made of metal such as iron in a spiral shape with the same radius and the same pitch around a linear axis.
The spring 3 has an elastic force in the axial direction and the radial direction.
Further, the diameter of the spring 3 is substantially the same as the inner diameter of the sleeve 2 before reducing the diameter (the diameter of the through hole 21) in a natural state where no external force is applied, and is inserted into the through hole 21 of the sleeve 2. can do.

Then, the detailed structure of the mechanical coupling 1 is demonstrated from a manufacturing process.
First, as shown in FIG. 2, the spring 3 is inserted into the insertion hole 21 of the sleeve 2 in a state where the axes of the sleeve 2 and the spring 3 are aligned. At this time, since the diameter of the through hole 21 and the diameter of the spring 3 are substantially the same, the spring 3 and the inner wall of the through hole 21 are in contact with each other.

Then, in a state where the spring 3 is inserted into the through hole 21, the entire outer peripheral surface of the sleeve 2 is pressed to reduce the diameter and plastically deform.
This step is performed, for example, by swaging. More specifically, as shown in FIG. 3, while the die 4 is rotated around the axis, the sleeve 2 in which the spring 3 is inserted into the through hole 21 is hit in the radial direction from the outer peripheral surface. Thereby, the diameter of the entire sleeve 2 is reduced and the sleeve 2 extends in the axial direction. In addition, the spring 3 in the through hole 21 is elastically reduced in diameter as the sleeve 2 is reduced in diameter to give a repulsive force to the inner peripheral surface of the sleeve 2 (inner wall of the through hole 21). It stretches elastically in the direction of the heart and is pulled. As a result, the spring 3 is firmly pressed against the inner wall of the through-hole 21 so that the sleeve 2 and the spring 3 are integrated.

The use and action of the mechanical joint 1 manufactured as described above will be described with reference to FIG.
In this example, as the reinforcing bars 5 and 6 to be joined, an irregular shape in which concave and convex ribs are formed on the outer peripheral surface to increase the adhesion to the filler 7 such as mortar and increase the force to resist the tensile force. Reinforcing bars are used.

When joining the ends of the two reinforcing bars 5 and 6, first, the end of the reinforcing bar 5 is inserted into the inner periphery of the spring 3 of the mechanical joint 1 from one end side, and the reinforcing bar 6 is connected from the other end side. The ends of both the reinforcing bars 5 and 6 are brought into contact with each other at the center of the mechanical joint 1.
Then, the filler 7 is injected into the through hole 21. When the filler 7 is solidified, the reinforcing bars 5 and 6 are joined from the mechanical joint 1 so as not to be pulled out. When the filler 7 is injected, the filler 7 enters the through hole 21 along the spiral shape of the spring 3, so that the filler 7 can be filled in the through hole 21 without a gap.

Hereinafter, the action of force in the joint structure will be described. For convenience of description, the center O is determined as shown in FIG. The center O constitutes the center point in the axial direction and the radial direction of the sleeve 1 and the center of gravity of the spring 3.
A tensile force F applied to the reinforcing bars 5 and 6 acts on the spring 3 via the filler 7. Therefore, the force that resists the tensile force F of the reinforcing bars 5 and 6 depends on the strength of fixing by the filler 7 and the force that resists the tensile force of the spring 3. Accordingly, attention is focused on the force against the tensile force of the spring 3, that is, the force acting on the reinforcing bars 5 and 6 in the direction opposite to the tensile force by the spring 3.

  Since the spring 3 is elastically reduced in diameter in accordance with the plastic deformation of the sleeve 2 in the circumferential direction, the spring 3 has a restoring force N directed radially outward from the center. Since the spring 3 and the inner peripheral surface of the through hole 21 are in contact with each other, the restoring force N acts as a vertical drag against the inner peripheral surface of the through hole 21 of the sleeve 2 at the contact point. To do. Therefore, the frictional force R1 proportional to the normal force acts in the direction opposite to the tensile force F on the inner peripheral surface of the through hole 21 of the sleeve 2 and the contact surface of the spring 3.

The spring 3 elastically extends from the center O outward in the axial direction in accordance with the plastic deformation of the sleeve 2 in the axial direction.
Therefore, in the axial direction, the spring 3 has a tension R2 as a restoring force in a direction from the end toward the center O, that is, in a direction opposite to the tensile force F.

  As described above, the resultant force of the frictional force R1 and the tension R2 acts on the reinforcing bars 5 and 6 inserted into the insertion hole 21 through the filler 7 in the axial direction. By this resultant force, the reinforcing bars 5 and 6 can resist the tensile force, and the reinforcing bars 5 and 6 are firmly connected.

The mechanical joint 1 according to the present embodiment described above can be manufactured by a simple process of pressing the entire outer peripheral surface of the sleeve 2 in which the spring 3 is inserted to reduce the diameter.
Further, since the entire sleeve 3 is plastically deformed, the mechanical joint 1 having high strength is provided by work hardening.
Further, when the mechanical joint 1 is manufactured, the spring 3 elastically contracts in the radial direction and elastically expands in the axial direction, so that a restoring force corresponding to the elastic expansion and contraction acts on the reinforcing bar. In addition, the reinforcing bars can be joined more firmly.

DESCRIPTION OF SYMBOLS 1 Mechanical coupling 2 Sleeve 21 Insertion hole 3 Spring 4 Dies 5, 6 Rebar 7 Filling material

Claims (3)

A mechanical joint that joins two rebars,
A cylindrical sleeve formed with an insertion hole with both ends open;
A spring having an elastic force and spirally winding a linear member,
The sleeve is generally reduced in diameter by plastic deformation,
The spring is elastically reduced in diameter in the radial direction according to the diameter of the insertion hole of the sleeve, and is elastically extended in the axial direction.
The spring is inserted into the through hole of the sleeve and is crimped to the inner wall of the through hole of the sleeve .
Reinforcing bar mechanical joint. A cylindrical sleeve having through holes formed at both ends and reduced in diameter by plastic deformation;
A spring having an elastic force and spirally winding a linear member,
The sleeve is generally reduced in diameter by plastic deformation,
The spring is elastically reduced in diameter in the radial direction according to the diameter of the insertion hole of the sleeve, and is elastically extended in the axial direction.
The spring is inserted into the insertion hole of the sleeve and is a joint structure for joining two reinforcing bars by a mechanical joint that is crimped to the inner wall of the insertion hole of the sleeve,
The two rebars are joined by a filler filled in the insertion hole of the sleeve, an end portion is inserted into the insertion hole of the sleeve whose spring is crimped to the inner peripheral surface,
Reinforcing bar joint structure. A cylindrical sleeve formed with an insertion hole with both ends open;
An elastic force, a spring by winding a linear member helically, by a method of joining two reinforcing bars,
In a state of being inserted the spring in transmural insertion hole of the sleeve, by Rukoto totally reduced in diameter by the sleeve is plastically deformed, the spring, according to the diameter of the transmural insertion hole of the sleeve diameter Elastically reducing the diameter in the direction and elastically extending in the axial direction, and crimping to the inner wall of the through hole of the sleeve;
Inserting two reinforcing bars into the inner periphery of the spring crimped to the insertion hole;
Filling the through hole with a filler.
A method for joining reinforcing bars.

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