JP4981574B2 - Fixing structure of braking nut and fastening bolt - Google Patents

Description

  The present invention relates to a fixing structure for braking nuts and fastening bolts, and more particularly to a fixing structure for braking nuts and fastening bolts used in prestressed concrete in the field of civil engineering and architecture.

  Conventionally, in order to improve the shortcomings of concrete with low tensile strength, a PC steel bar is embedded in the concrete, tensile stress is applied to the PC steel bar, and compression stress is applied to the concrete in advance so that it is strong against both compression and tension. As a concrete structure, a prestressed concrete structure is known. Thus, it is known that when a tensile stress is applied to an embedded PC steel rod, the nut is tightened from the outside via an anchor plate with a nut (Patent Document 1).

Japanese Patent Laid-Open No. 6-146381

  However, according to the invention described in Patent Document 1, the hole diameter of the anchor plate is generally processed to be larger than the outer diameter of the male screw of the PC steel rod, and the insertion of the PC steel rod and the anchor plate or the like is performed. A gap occurs in the part. For this reason, the PC steel bar is exposed to the outside air, and water or the like enters from the outside, which may cause corrosion or rusting. Therefore, it is necessary to fill with rust preventives such as grout at the end of the process, which causes problems such as increased man-hours, longer construction periods, and increased costs due to increased parts for injecting rust preventives such as grout. It was.

  An object of the present invention is to provide a braking nut and a fixing structure for a fastening bolt that can rust-proof the fastening bolt without water or the like entering the insertion portion between the fastening bolt and the anchor plate from the outside.

The braking nut according to the present invention is used when the nut presses the anchor plate by being screwed into the fastening bolt, and is disposed on the opposite side of the nut with the anchor plate interposed therebetween. A braking nut that is fitted in an anchor plate through-hole formed in the anchor plate, and extends to the locking portion, and is larger than an outer diameter of the locking portion. A fastening portion formed in a large cylindrical shape, and the fastening portion and the locking portion have a first through-hole and a second through-hole through which the fastening bolt is inserted, and the first through-hole and the first through-hole. A first waterproof part and a second waterproof part that prevent water from entering the fastening bolt from the outside are provided at least at the end of the inner peripheral surface of the two through holes. Department and front The fastening bolt close contact, said second waterproof portion provided at an end portion of the inner peripheral surface of the first waterproof portion provided at an end portion of the inner peripheral surface and the second through-hole of the first through hole The inner peripheral surface of the locking part between the two is formed in a cylindrical surface .

In the present invention, the fastening bolt is inserted into the first through hole and the second through hole of the breaking nut, so that it is provided at least at the end portion of the inner peripheral surface of the first through hole and the second through hole of the breaking nut. The first waterproof portion and the second waterproof portion are in close contact with the fastening bolt. As a result, water and the like can be prevented from entering from the outside. Moreover, since it is a braking nut formed integrally with the fastening portion and the locking portion, there is no gap between the anchor plate and the fastening portion, and entry of water or the like from the outside can be prevented. Furthermore, since the locking portion is fitted in the anchor plate through hole, it is possible to further prevent water and the like from entering the fastening bolt from the outside.
Further, the inner peripheral surface of the locking portion between the first waterproof portion and the second waterproof portion provided at the end portions of the inner peripheral surface of the first through hole and the second through hole is a cylindrical surface. Since the first waterproof portion and the second waterproof portion are formed at the end portions of the first through hole and the second through hole of the fastening portion and the locking portion, the first waterproof portion and the second waterproof portion are formed by the tensile force of the fastening bolt. The shearing force received by the waterproof part and the second waterproof part is smaller than when the waterproof part is formed on all the inner peripheral surfaces of the first through hole and the second through hole. That is, when the waterproof portion is formed on all the inner peripheral surfaces of the first through hole and the second through hole, a shearing force is generated on the entire inner peripheral surfaces of the first through hole and the second through hole, so that the breaking nut is broken. There is a fear. Therefore, in the case where tensile stress is applied from both ends of the fastening bolt, the risk of breaking the breaking nut can be reduced by providing a waterproof portion at the end portions of the inner peripheral surfaces of the first through hole and the second through hole. Therefore, it is possible to more reliably prevent water and the like from entering the fastening bolt from the outside.
Moreover, the shear force which a 1st waterproof part and a 2nd waterproof part receive by the tension | tensile_strength of a fastening bolt can be reduced by forming in the cylindrical surface between the 1st waterproof part and the 2nd waterproof part. Accordingly, as described above, the risk of breaking the breaking nut can be reduced, so that the entry of water or the like from the outside to the fastening bolt can be more reliably prevented.

Here, in the invention of the braking nut, it is preferable that the fastening portion and the locking portion are separated.
In this invention, since the fastening portion and the locking portion are separated, the fastening portion and the locking portion are not sheared and destroyed by the tensile force of the fastening bolt. Therefore, since there is no possibility that the breaking nut will break, it is possible to more reliably prevent water and the like from entering from the outside.

It is preferable that a third waterproof part is provided between the first waterproof part and the second waterproof part so as to cover an inner peripheral surface of the second through hole.
In the present invention, when the shearing force received by the first waterproof part and the second waterproof part is small due to the tensile force of the fastening bolt, such as the fixed end side of the fastening structure of the fastening bolt, the first waterproof part and the second waterproof part are provided. By providing the third waterproof part between the two parts, water and the like can be more reliably prevented from entering the fastening bolt from the outside.

Furthermore, in the invention of the braking nut, it is preferable that the first waterproof part and the second waterproof part are formed in a screw shape.
In the present invention, the fastening bolt is configured to be screwed into the thread portions of the first waterproof portion and the second waterproof portion of the braking nut. Then, by fastening the nut from the outside, a tensile force is generated in the fastening bolt, and a shearing force is applied to the screw portion. As a result, the threaded portion of the braking nut screwed to the fastening bolt is deformed, and the adhesion with the fastening bolt is further improved. Therefore, it is possible to further prevent water and the like from entering the fastening bolt from the outside.

The fastening bolt fixing structure according to the present invention includes a fastening bolt, a nut that is screwed to the fastening bolt, an anchor plate that is in contact with the nut and has an anchor plate through hole through which the fastening bolt is inserted, and The braking nut according to any one of Items 1 to 5 is provided.
According to the present invention, it is possible to provide a fastening bolt fixing structure capable of producing the above-described effects.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view in which a breaking nut according to the present invention is used for a PC steel rod. FIG. 2 is a side sectional view of the braking nut. FIG. 3 is a perspective view of the anchor plate. FIG. 4 is a side sectional view of the breaking nut after deformation.

A fixing structure of the PC steel rod 10 as a fastening bolt in which the braking nut 14 shown in FIG. 1 is used will be described. The fixing structure of the PC steel bar 10 is an anchor plate having a PC steel bar 10 embedded in the concrete 21, a nut 11 fitted to the PC steel bar 10, and an anchor plate through-hole 161 through which the PC steel bar 10 can be inserted. 16 and a breaking nut 14 embedded in the concrete 21, fitted into the PC steel rod 10, and inserted to the anchor plate through hole 161 of the anchor plate 16.
A washer 12 is provided between the nut 11 and the anchor plate 16.
The PC steel rod 10 has a male thread portion 101 at the circumferential portion, and the nut 11 is a general-purpose one that is generally commercially available.

Here, the PC steel bar 10 is embedded in the concrete 21, and both ends thereof are tightened by the nut 11, so that the anchor plate 16 presses against the concrete 21. Then, tension is applied to the PC steel bar 10. Thus, compressive stress is applied to the concrete 21 in advance to improve the strength.
Further, there is a structure in which the PC steel bar 10 is embedded in the concrete 21, one end is fixed, the nut 11 is tightened, and tension is applied to the PC steel bar 10.

Next, the braking nut 14 shown in FIG. 2 will be described.
The braking nut 14 includes a fastening portion 141 formed in a cylindrical shape and a locking portion 143 formed in a cylindrical shape having a smaller outer diameter than the fastening portion 141. The braking nut 14 may be configured integrally with the fastening portion 141 and the locking portion 143 or may be configured separately.

  The fastening portion 141 includes a first through hole 141A for inserting the PC steel rod 10, and a first waterproof portion for screwing the male thread portion 101 of the PC steel rod 10 into the end portion of the inner surface of the first through hole 141A. 142A.

  The first waterproof portion 142A may not be formed in a screw shape. In other words, when the fastening portion 141 is inserted into the PC steel rod 10, it is sufficient that the fastening portion 141 is in close contact with the male thread portion 101 of the PC steel rod 10, so that the fastening portion 141 is formed in a convex shape or a projection shape. As long as it can prevent the intrusion of water or the like from the outside. In addition, airtightness can also be improved by previously filling the PC steel rod 10 screwed with the first waterproof part 142A and the second waterproof part 142B with a rust inhibitor or the like.

  The locking portion 143 includes a second through hole 143A for inserting the PC steel rod 10 and a second waterproof for screwing the end portion of the inner surface of the second through hole 143A with the male screw portion 101 of the PC steel rod 10. Part 142B.

  The 2nd waterproof part 142B is formed in the edge part of the internal peripheral surface of the through-hole of the latching | locking part 143, and another internal peripheral surface is formed as a cylindrical surface. That is, the waterproof part is not formed on the cylindrical surface. Moreover, the 2nd waterproof part 142B does not need to be formed in screw shape similarly to the 1st waterproof part 142A.

  FIG. 2 shows a case where the shearing force applied to the first waterproof part 142A and the second waterproof part 142B is small due to the tensile force of the PC steel bar 10, such as the fixed end side of the fixing structure of the PC steel bar 10. Further, by providing the third waterproof portion 142C, it is possible to more reliably prevent water and the like from entering the PC steel rod 10 from the outside.

  The material of the breaking nut 14 is preferably a synthetic resin such as high-density polyethylene. When the nut 11 is tightened, the anchor plate 16 presses the concrete 21 and a tensile force is generated in the PC steel bar 10. Therefore, according to this material, only the first waterproof part 142A and the second waterproof part 142B provided on the breaking nut 14 are destroyed without shearing the breaking nut 14. Therefore, by using these materials, as shown in FIG. 4, the first waterproof part 142A and the second waterproof part 142B can be transformed into the deformed waterproof part 143C. This deformation improves the adhesion between the male threaded portion 10 of the PC steel rod 10 and the deformed waterproof portion 143C.

Here, the anchor plate 16 will be described with reference to FIG.
As shown in FIG. 3, the anchor plate 16 is formed in a rectangular parallelepiped shape, and has an anchor plate through-hole 161 through which the PC steel rod 10 is inserted at the center.
Further, as shown in FIG. 2, the anchor plate 143 of the braking nut 14 is inserted into the anchor plate through-hole 161. An anchor plate 16 is fastened with a nut 11 through a washer 12.

Therefore, in the present embodiment, the following operational effects can be achieved.
(1) When the thread is broken by the tensile force of the PC steel rod 10, the first waterproof portion 142A and the second waterproof portion 142B are deformed into the deformed waterproof portion 143C, and the PC steel rod 10 Adhesion can be improved and water can be prevented from entering from the outside.
(2) The PC steel rod is formed by forming the first waterproof portion 142A and the second waterproof portion 142B at the end of the first through hole 141A and the second through hole 143A of the fastening portion 141 and the locking portion 143. With the tensile force of 10, the shearing force applied to the breaking nut 14 can be reduced.
(3) The locking portion 143 is configured such that the inner circumference of the second through hole 143A is a cylindrical surface, so that the PC steel rod 10
The shearing force applied to the breaking nut 14 can be reduced by the tensile force of.

(4) Since the second waterproof portion 142B is formed at the end portion of the inner peripheral surface of the second through hole 143A provided in the locking portion 143, intrusion of water or the like from the outside can be prevented. The locking part 143 is located in a place close to the outside air, and it is more effective to provide the second waterproof part 142B.
(5) Since the locking portion 143 is fitted in the anchor plate through-hole 161, it is possible to prevent water or the like from entering the PC steel rod 10 from the outside.
(6) Since the fastening portion 141 and the locking portion 143 are integrally formed, there is no gap between the anchor plate 16 and the fastening portion 141 due to the tensile force of the PC steel rod 10, and the outside Intrusion of water etc. can be prevented.

(7) The concave portion 144 included in the fastening portion 141 can store the sheath covering the PC steel rod 10 through the PC steel rod 10.
(8) Since the adhesion between the PC steel rod 10 and the deformed waterproofing portion 143C is improved, there is no need to inject a rust inhibitor into the PC steel rod 10, and parts used in the process of injecting the rust inhibitor are also necessary. No cost can be reduced.

  The present invention is not limited to the above-described embodiment, and includes other configurations that can achieve the object of the present invention, and includes the following modifications and the like.

For example, in the present invention, the fastening portion 141 has a cylindrical shape, but may be a polygonal column such as a square column or a hexagonal column so that it can be easily tightened with a work tool.
In the above embodiment, the braking nut 14 has been described in which the fastening portion 141 and the locking portion 143 are integrated, but these may be separated.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used when a PC steel bar used in the civil engineering / architecture field is introduced into prestressed concrete.

Schematic which used the breaking nut which concerns on embodiment of this invention for PC steel rod. The sectional side view of the above-mentioned braking nut. The perspective view of the anchor plate which concerns on the said embodiment. The side sectional view after the deformation | transformation of the 1st waterproof part formed in the said braking nut and the 2nd waterproof part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... PC steel rod as a fastening bolt, 11 ... Nut, 14 ... Breaking nut, 16 ... Anchor plate, 21 ... Concrete, 101 ... Male thread part, 141 ... Fastening part, 141A ... 1st through-hole, 142A ... 1st Waterproof part, 142B ... 2nd waterproof part, 142C ... 3rd waterproof part, 143 ... Locking part, 143A ... 2nd through-hole, 143C ... Deformation waterproof part, 161 ... Anchor plate through-hole.

Claims (5)

The nut is screwed into the fastening bolt, and is used when the nut presses the anchor plate, and is a braking nut disposed on the opposite side of the nut across the anchor plate,
A cylindrical locking portion fitted in an anchor plate through hole formed in the anchor plate;
A fastening portion extending in the locking portion and formed in a cylindrical shape larger than the outer diameter of the locking portion;
The fastening portion and the locking portion have a first through hole and a second through hole through which the fastening bolt is inserted, and at least an end portion of an inner peripheral surface of the first through hole and the second through hole, A first waterproof part and a second waterproof part for preventing water from entering the fastening bolt from the outside, and the first waterproof part and the second waterproof part and the fastening bolt are in close contact with each other;
The locking between the first waterproof portion provided at the end portion of the inner peripheral surface of the first through hole and the second waterproof portion provided at the end portion of the inner peripheral surface of the second through hole. The braking nut characterized by the inner peripheral surface of a part being formed in the cylindrical surface . The braking nut according to claim 1,
The breaking nut, wherein the fastening portion and the locking portion are separated. The braking nut according to claim 1 or 2 ,
A braking nut, wherein a third waterproof part is provided between the first waterproof part and the second waterproof part so as to cover an inner peripheral surface of the second through hole. In the braking nut according to any one of claims 1 to 3 ,
The braking nut according to claim 1, wherein the first waterproof part and the second waterproof part are formed in a screw shape. Fastening bolts,
A nut screwed onto the fastening bolt;
An anchor plate having an anchor plate through hole that is in contact with the nut and through which the fastening bolt is inserted;
A fastening nut fixing structure comprising the breaking nut according to any one of claims 1 to 4 .

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