JP2002254179A - Joining method for rodlike body and protective sleeve for joining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joining method for rodlike bodies and a protective sleeve for joining capable of conducting the joining stably and firmly, contriving simplification of post treatment after completion of the joining work, and flattening the surface of the joined part. SOLUTION: A pair of the rodlike bodies 2, 2 are butt-arranged, and the protective sleeve 1 provided with a flux on the inner periphery is arranged on the periphery of the butt-ends 19, 19. The both butt-ends 19, 19 are brought into butt-contact with each other in a heating state. In bringing the butt-end 19 into butt-contact, the temperature of the flux is raised to generate gas, slag, etc., and the joining part 20 is protected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining rods and a protective cylinder for joining.

[0002]

2. Description of the Related Art Reinforcing bars and the like used for concrete structures such as civil engineering and buildings are formed by joining rods in the longitudinal direction thereof. In the joining method, the end faces of a pair of rods are butted, and in this state, the joining ends are heated with acetylene oxide gas or the like while applying a compressive force in the longitudinal direction. However, since such a gas pressure welding is performed outdoors, it is very difficult to perform the work in rainy weather, and the work is manually performed by an operator.
Variations occurred in the bonding strength, and there was a problem with the quality. Therefore, a joining method using a joining protective cylinder as shown in FIG. 11 has been developed. That is, this joining protective cylinder is made of, for example, a short cylinder made of ceramics, and has a spiral groove 41 provided on the outer peripheral surface 40 thereof. A coil (not shown) of the high-frequency induction heating device is fitted into the spiral groove 41. Is what is done. In the joining method using the joining protective cylinder, first, a pair of rods 42 to be joined are butt-arranged, and this protective cylinder is joined to both butting ends 4 of the rods 42, 42.
It is arranged around 3, 43. In this state, a high-frequency current is caused to flow through the coil of the high-frequency induction heating device to heat the two butted ends 43.
2, 42 were joined by pressing them in a direction approaching each other.

[0003]

By the way, in the joining step, the butted ends 43, 43 bulge to form a joint, and the bulged joint may be pressed against the inner peripheral surface of the protective cylinder. there were. For this reason, biting occurs between the joint and the protective cylinder, and the surface of the formed joint (bulge) is not finished smoothly, and after joining, the protective cylinder is removed from the joint. If it is necessary and it is stuck, removal of the protective cylinder was troublesome. In addition, the surface of the joint is not subjected to any antioxidant treatment, and easily deteriorates,
The joint was inferior in strength.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks, and has as its object to stably and firmly join, and to simplify post-processing after completion of the joining operation. It is an object of the present invention to provide a joining method of a rod-shaped body and a joining protective cylinder capable of smoothing the surface of a joining portion, and a joining cylinder.

[0005]

According to a first aspect of the present invention, there is provided a method of joining rods, wherein a pair of rods are arranged in a butt manner, and both butt ends are heated, and both butt are heated. In the joining method of the rod-shaped members for crimping the ends 19, 19, the protective cylinder 1 having a flux on the inner periphery is disposed around the two butted ends 19, 19, and At the time of pressure bonding, the temperature of the flux 3 is raised to generate gas, slag, and the like, thereby protecting the joint portion 20.

In the method for joining rods according to the first aspect of the present invention, the flux generates gas when the butted ends 19 and 19 are pressed, so that oxidation and nitriding of the joint 20 can be prevented. The joint 20 is effectively protected.
In addition, since the flux 3 generates molten slag, the molten slag comes into contact with the joining portion and effectively prevents biting.

According to a second aspect of the present invention, there is provided a method for joining rods, wherein a pair of rods is arranged and heated, and both butted ends are heated and crimped. In the joining method of the rods, the protective cylinder 1 is disposed around the two butted ends 19, 19, and then the granular flux 3 is injected between the protective cylinder 1 and the butted ends 19, 19. When the butt ends 19, 19 are crimped, the temperature of the flux 3 is raised to generate gas, slag, etc., thereby protecting the joint portion 20.

In the method for joining rods according to the second aspect, the joint portion 20 is protected and the same as in the first aspect.
Entrapment between the joint 20 and the protective cylinder 1 is also prevented. In addition, since the particulate flux 3 only needs to be supplied during the joining operation, the flux 3 does not easily absorb moisture, and the oxidation and nitriding of the joined portion 20 can be reliably prevented. Furthermore, the use of the granular flux 3 makes it possible to finish the surface more beautifully, and the peelability of the protective cylinder 1 after the joining operation is particularly excellent.

According to a third aspect of the present invention, a pair of rod-like bodies 2 and 2 are butt-arranged.
19. A method of joining rod-shaped members, which heats the two ends 19 together while pressing the two ends together in a heated state.
9. A joining protection cylinder disposed around 9, 19,
It has a cylindrical main body 4 and a flux 3 provided on the inner peripheral surface 5 of the cylindrical main body 4. When the temperature of the flux 3 rises when the butting ends 19, 19 are crimped, gas,
It is characterized in that slag and the like are generated to protect the joint 20.

According to the third aspect of the present invention, the flux 3 generates gas when the butting ends 19 and 19 are pressed, so that oxidation and nitriding of the joint 20 can be prevented. , The joint 20 is effectively protected.
Further, since the flux generates the molten slag, the molten slag comes into contact with the joint portion 20 and effectively prevents biting.

According to a fourth aspect of the present invention, the joining protective cylinder is disposed around the butted ends 19, 19, and is in the form of a rod-shaped body 2.
It is characterized in that a gap which is 10 to 25% of the outer diameter D of the rod-shaped body 3 is provided between the cylindrical body 4 and the inner peripheral surface 5 of the cylindrical body 4.

According to the fourth aspect of the present invention, during the joining step, the joining portion 20 does not press against the inner peripheral surface 5 of the tubular main body 4.
Engagement can be reliably prevented.

The joint protection cylinder according to a fifth aspect is characterized in that a concave groove 21 is provided on the inner peripheral surface 5 of the cylindrical main body 4 and a flux is arranged in the concave groove 21.

In the protective cylinder for bonding according to the fifth aspect, if the flux arrangement site corresponds to the butted surface (end surface) of the rods 2, the flux 3 oxidizes the bonded portion,
Since it is possible to prevent nitriding and to effectively prevent entrapment, a minimum necessary flux amount is required.
Moreover, since the flux 2 is arranged in the concave groove 21, the flux 2 can be prevented from coming off. Further, it is not necessary to coat the inner peripheral surface 5 of the cylindrical main body 4 with the flux 2, and it is possible to prevent the outer diameter of the cylindrical main body 4 from increasing.

In a sixth aspect of the present invention, the joining protective cylinder is characterized in that a plurality of slits 22 are formed along the axial direction.

In the protective cylinder for joining according to the sixth aspect, since the plurality of slits 22 are formed along the axial direction,
It is possible to divide this joining protection cylinder, and if it is divided before the joining step, the work of arranging this joining protection cylinder at the butting ends 19, 19 becomes easy, and it is also possible to divide it. Even if it is arranged at the butting ends 19, 19 and the joining step is performed, the joining protective cylinder can be divided, and the joining protective cylinder can be easily removed from the joining section 20.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a protective cylinder for joining according to the present invention.
Embodiments will be described in detail with reference to the drawings.
You. FIG. 1 is a sectional view of a joint protection cylinder according to this embodiment.
FIG. 3 is a front view of the protection cylinder 1 for joining, which is a pair of rod-shaped bodies.
It is used at the time of butt joining of 2, 2. This rod shape
The body 2 is used for concrete structures such as civil engineering and architecture.
Reinforcing bars and so on. This joining protection cylinder 1 is formed of
It has flux 3 on the periphery and is made of ceramic
And a cylindrical body 4 having a short cylindrical body, and an inner peripheral surface 5 of the cylindrical body 4.
Consisting of the flux 3 provided above. And cylindrical
A spiral groove 7 is formed on the outer peripheral surface 6 of the main body 4. this
A coil 8 is wound around the spiral groove 7 as shown in FIGS.
Is established. This coil 8 is a coil of a high-frequency induction heating device.
High-frequency current
And the cooling water is supplied to the inner hollow portion 9.
You. By the way, as the cylindrical main body 4, for example,
The component is SiO _Two(35-42% by weight), Al_TwoO_Three(5
6-63% by weight), K_TwoO (0.2-2.0% by weight),
Na_TwoO (0.1-2.0% by weight) and other unavoidable
Impurity (0.5-1.3% by weight) alumina silicate
use.

The flux 3 is, for example, S
iO ₂ (40 to 44 wt%), Al ₂ O ₃ (43 to 48 wt%), Na ₂ O (8 to 13 wt%), and those other unavoidable impurities (1-2 wt%) and component use,
Furthermore, what is used as a coating material of a welding rod can be used, for example, a coating material of a welding rod of D4311 is used. In this case, a fixing agent (aqueous solution such as sodium silicate and potassium silicate) is mixed with cellulose, titanium oxide, asbestos, high carbon ferromanganese, talc, and the like. That is, the flux 3 is applied in an aqueous solution state to the inner peripheral surface 5 of the cylindrical main body 4 and solidified.

As shown in FIG. 1, the joining protection cylinder 1 has an inner diameter A set to be larger than the outer diameter D of the rods 2, 2 to be joined. A gap G (see FIG. 4), which is 10% to 25% of the outer diameter D of the rod 2, is provided between the inner peripheral surface 5 and the inner peripheral surface 5. Specifically, when the inner diameter dimension A is set to about 25 mm to 60 mm, the thickness T of the flux 3 is set to about 2 to 8 mm. The thickness T ₀ of the cylindrical body 4 and the depth of the spiral groove 7 determine the inner diameter of the coil 8, and the spiral angle of the spiral groove 7 determines the pitch of the coil 8. Yes, these are
Since this is an important factor in high-frequency induction heating, it is determined in consideration of the material, size, and the like of the rods 2 to be joined so that the rods 2 can be heated to a desired temperature during joining. There is a need. The length L ₀ of the joining protection cylinder 1 is a length corresponding to abutting ends 19, 19 of the rods 2, which will be described later.

When the rods 2 and 2 are joined by using the joining protection cylinder 1 having the above-described structure, a holding device 10 shown in FIG. 4 is used. This holding device 10
Is a pair of clamp bodies 11 and 12 and this clamp body 1
Support body 1 supporting arms 1 and 12 via arms 15 and 16
3 and one (lower) clamp body 12
Is clamped, and the other (upper) clamp body 11 is clamped.
To clamp the other (upper) rod 2. In order to clamp the rods 2, 2 with the respective clamps 11, 12, bolt members 14. Further, the other clamp body 11 moves toward and away from one clamp body 12 as shown by an arrow in FIG. That is, the arm 15 supporting the clamp body 11 is moved up and down by driving means (not shown), and the clamp body 11 is moved up and down. As the driving means, for example, a publicly known driving means such as a cylinder mechanism or a link mechanism can be used. Further, the upper clamp 11 may be used as a fixed side, and the lower clamp 12 may be used as a movable side, or both clamps 11 and 12 may be movable relative to each other.

Next, the protective cylinder 1 for joining and the holding device 1
The bonding method according to the present invention will be described using 0 and the like.
First, as shown in FIG.
The lower bar 2 is clamped. At this time, the tip portion 17 of one of the rods 2 is projected from the clamp body 12. Next, the joining protection cylinder 1 in which the coil 8 is wound along the spiral groove 7 is attached to the rod-shaped body 2 projecting from the clamp 12.
Is fitted around the tip 17 of the head. In this case, the joining protective cylinder 1
Is larger than the outer diameter D of the rod-shaped body 2, so that the inner diameter A is loosely fitted and is in contact with the lower clamp 12. Thereafter, the other rod-shaped body 2 is clamped by the upper clamp 11 such that the end face 2a of the rod-shaped body 2 abuts against the end face 2a of the one rod-shaped body 2. That is, the base end 18 of the other rod-shaped body 2 is projected from the clamp 11. In this case, the axes of the rods 2, 2 are arranged on the same straight line (vertical line). Next, a cable (not shown) of the high-frequency heating induction device is connected to the connection end of the coil 8, the positioning of the joining protection cylinder 1 is performed, and the cable is fixed to the support 13 of the holding device 10. As shown in FIG. 4, the positioning is a positioning in which the mating surfaces 2 a of the rods 2 correspond to the axial center of the joining protection cylinder 1, and the butt ends. This is to dispose the joining protective cylinder 1 around 19, 19. In addition, as a means for fixing the cable, a bolt / nut connection or the like can be used.

Then, in the state set as described above,
The high-frequency induction heating device is turned on, and a high-frequency current of the coil 8 flows. This produces an alternating magnetic flux, which induces eddy currents through the rods 2,2. At that time, Joule heat is generated at the butted ends 19 of the rods 2. As a result, the butted ends 1 of the rods 2
9 and 19 are heated, and the butted ends 19 and 19 become molten. In this state, the upper clamp 11 is slightly moved downward, and the lower rod 2 is pressed and pressed by the upper rod 2. As a result, the pair of rods 2 are pressed. Then, the cable and holding device 10
And at the same time, the connecting protection cylinder 1 is connected to the connecting portion 20 (FIG. 1).
(See FIG. 2), the joining operation is completed. In addition, by flowing cooling water through the hollow portion 9 of the coil 8, the joining portion 20 can be cooled. When the joining protective cylinder 1 is to be removed, it may be broken by tapping lightly with a tool such as a hammer.

In this case, the gas (for example, from the flux 3 at the inner peripheral portion of the joining protection cylinder 1) is heated by the heating during the joining.
H ₂ , CO, CO _2, etc.) are generated (generated), and the gas is used to cover the joint 20, thereby preventing oxidation and nitridation of the joint 20. Further, the flux 3 generates molten slag, and the molten slag is interposed between the joining portion 20 and the cylindrical main body 4 of the joining protective cylinder 1,
Smoothing of the surface of the joint 20 can be achieved,
Moreover, after joining, the slag is solidified and has excellent releasability, and the work of removing the joining protective cylinder 1 becomes easy. By the way, as mentioned above, flux 3
When the thickness T is set smaller than this range, the above function as the flux 3 is not sufficiently exhibited.
Conversely, if it exceeds this range, the amount of the flux 3 will be too large, and waste of material will occur, and the inner diameter of the joining protection cylinder 1 will be small, making it difficult to set it on the rod 1. It is. The reason why the gap G between the inner peripheral surface 5 of the cylindrical main body 4 and the rod 2 is set as described above is as follows.
If it is smaller than this, the inner peripheral surface 5 of the cylindrical main body 4 and the joining portion 20 may be pressed against each other during the joining operation and may bite. On the other hand, if it is larger than this, the inner diameter of the coil 8 to be wound, etc. This is because the wall thickness of the cylindrical main body 4 cannot be made sufficiently large in the above relationship.

Next, FIG. 5 shows another embodiment of the joining protective cylinder 1. In this case, the flux 3 is provided only at the axial center portion of the joining protective cylinder 1. That is, the axial length L of the flux 3, set shorter than the axial length L ₀ of the tubular body 4, the end surface 2a, and only in correspondence of the flux 3 neighborhood of 2a. Even when the rod-shaped bodies 2 and 2 are joined using the joining protection cylinder 1, the same operation and effect as those of the joining protection cylinder 1 shown in FIG. 1 can be obtained. In addition, there is an advantage that the cost can be reduced by the reduced amount of the flux 3.

FIG. 6 shows another embodiment of the joining protective cylinder 1. In this case, a concave groove 21 is provided on the inner peripheral surface 5 of the cylindrical main body 4, and the concave groove 21 is The flux 3 is arranged at the bottom. In this case, the concave groove 21 is provided at a central portion in the axial direction, and has a circular cross section. The inner peripheral surface 3a of the flux 3 and the inner peripheral surface 5 of the cylindrical main body 4 are arranged on the same plane. Also in this case, similarly to the joining protective cylinder 1 shown in FIG. 5, the axial length L of the flux 3 is set short, and the flux 3 is made to correspond only to the vicinity of the end faces 2a, 2a. Further, the maximum thickness T ₁ of the central portion in the axial direction of the flux 3 is set to be substantially the same as the thickness T of the flux 3 of the joining protective cylinder 1 shown in FIGS. Further, the distance from the rod 2 to the deepest part of the concave groove 21 is 10 to 25% of the outer diameter D of the rod 2. Therefore, even when the rods 2 and 2 are joined using the joining protective cylinder 1, the same operation and effect as those of the joining protective cylinder 1 shown in FIG. 1 can be obtained. Further, since the flux 3 is arranged in the concave groove 21, the flux 3
There is an advantage that the peeling of the joint protection tube 1 is effectively prevented, and the handling of the joining protective cylinder 1 is facilitated. Further, since the flux 3 is not coated on the inner peripheral surface 5 of the cylindrical main body 4, the outer diameter of the cylindrical main body 4 is prevented from being enlarged, and the inner diameter of the coil 8 wound around the joining protective cylindrical body 1 is prevented. Can be prevented from expanding,
This makes it possible to perform effective heating of the effective butted ends 19, 19.

The concave groove 21 may have a substantially rectangular cross section as shown in FIG. In this case, in the illustrated example, the open ends 21a and 21b of the concave groove 21 are formed in a round shape (rounded shape). This is for beautifully finishing the joint 20 to be formed. Also,
The capacity of the concave groove 21 corresponds to the bulging of the rod-shaped body 2 so that the protective cylinder 1 is not broken at the time of pressurization.
For this reason, as long as this capacity is ensured, the concave groove 21 may have various cross-sectional shapes such as a substantially V shape, a semi-ellipse to a semi-ellipse, or a semi-polygonal shape.

As shown in FIG. 8, a concave groove 21 is provided in the cylindrical main body 4 of the protective cylindrical body 1, and as shown in FIG. The flux 3 may be additionally provided. Of course, the shape of the concave groove 21 is not limited to this.

As still another embodiment, as shown in FIG. 9, the protection cylinder 1 is constituted by only the cylindrical main body 4 and
As the flux 3, a particulate flux may be used. In this case, the flux drop prevention portion 25 is provided on the one opening (lower opening) side of the cylindrical main body 4. As the flux drop prevention portion 25, for example, an inner flange-shaped inwardly projecting piece is provided at the lower opening of the cylindrical main body 4, or the rod 2 has excellent heat resistance in the vicinity of the lower opening of the cylindrical main body 4. What is necessary is just to wind and form a linear body (for example, glass wool etc.). The granular flux 3 is powdery granular slack used for submerged arc welding or the like. In the case of FIG. 9, the concave groove 21 having the shape shown in FIG. 7 is formed on the inner peripheral surface 5 of the cylindrical main body 4.
May have the shape shown in FIG. 6 or may not have the shape.

In order to perform the joining operation using the protective cylinder 1, first, as in the above-described embodiments, the mating surfaces 2a, 2a of the rods 2, 2 are attached to the protective cylinder 1. The protective cylinder 1 on which the coil 8 is wound is disposed around the butting ends 19, 19 after the positioning is performed so as to correspond to the central part in the axial direction. In addition, although the spiral groove 7 is not formed in the protective cylinder 1 in this case, the protective cylinder 1 may have the spiral groove 7 as a matter of course. In such a state, the granular flux 3 is supplied to the gap between the inner peripheral surface 5 of the protective cylinder 1 and the rods 2, 2, and a high-frequency current of the coil 8 flows. As a result, the butted ends 19, 19 of the rods 2, 2 are melted, and in this state, one or both of the upper and lower rods 2, 2 are pressed in the approaching direction, and the pair of rods 2, 2 are pressed. 2 is crimped. Thereafter, the cable and the holding device 10 (not shown) are removed, and the joining protection cylinder 1 is detached from the joining portion 20. This joining operation is completed. When the joining protective cylinder 1 is to be removed, it may be broken by gently tapping it with a tool such as a hammer as described above.

When the joining operation is performed using the protective cylinder 1 shown in FIG. 9, the joint 20 is covered with the gas from the flux 3 as in the above-described embodiments. Oxidation and nitridation of the joint 20 can be prevented.
In addition, the flux 3 generates molten slag, and the molten slag is interposed between the joining portion 20 and the joining protection cylinder 1, so that the surface of the joining portion 20 can be smoothed. In addition, since it is sufficient to supply the granular flux 3 at the time of the joining operation, the flux 3 is hard to absorb moisture, the high quality joining portion 20 can be formed, and the oxidation and nitriding of the joining portion 20 can be reliably prevented. Can be. Further, by using the granular flux 3, it is possible to finish the surface more beautifully, and it is excellent in the releasability of the protective cylinder 1 after the joining operation. It also contributes to cost reduction.

In the above embodiments, since the protective cylinder 1 is detached from the joint portion 20 after the joining operation is completed, the protective cylinder 1 is composed of a plurality of segments and the joining operation is completed. Preferably, later separation is possible.
However, when a plurality of segments are formed and then assembled, since the spiral groove 7 is provided in the cylindrical body 1 to be formed, it is extremely difficult to form a continuous spiral groove. The cylindrical main body 4 is made of ceramic, and is warped or distorted during sintering, and has a problem in dimensional accuracy. Therefore, as shown in FIG. 10, after the cylindrical main body 4 is formed, a plurality of slits 2 (two in the illustrated example, but may be three or more) along the axial direction.
Those formed with 2, 22 are used. In this case, if a slight impact is applied to the cylindrical main body 4, the cylindrical main body 4 can be divided (divided into two). In this state, if the coil 8 is wound around and the flux 3 is provided inside, the rod-shaped body 2, like the joining protective cylinder 1 in FIG.
2 becomes the most suitable for the joining operation, and the cylindrical body 4
Are divided, so that the work of removing the joining protective cylinder 1 after the joining work can be simplified. Also,
The protective cylinder 1 having the slit 22 may be used without being divided, and after the joining operation is completed, the protective cylinder 1 for joining may be subjected to an impact to be divided. Also in this case, it can be easily removed from the joint 20. In the case where the slit 22 is formed, it is preferable that the radial length of the remaining portion 23 is, for example, about 2 to 4 mm. In addition, as described above, in the case of the divided one or the one having the slit 22, there is a possibility that the joining protective cylinder 1 is divided and detached from the joint part 20 during the joining operation.
Since the surface of the joint 20 is deteriorated or short-circuited at a high frequency, the protective cylinder 1 for joining is tied with a binding member (for example, a metal wire or the like) excellent in heat resistance or the like in order to prevent the deterioration. It may be.

Although the embodiments of the method for joining rods and the protective cylinder for joining according to the present invention have been described above, the present invention is not limited to the above embodiments, and the scope of the present invention is not limited thereto. Various changes can be made within the embodiment. For example, as a component of the flux 3, a gas, a slag, and the like are generated by a rise in temperature, and the melting point is about 1000 ° C. to 1200 ° C., so that the gas does not react with the metal of the rod 2 at the time of gas generation. Can be changed freely. In addition, as the material of the tubular main body 4 of the joining protection tubular body 1, any material other than ceramic that is insulative and does not melt or deform at the time of joining can be adopted. As means for heating the butted ends 19, 19, besides the high-frequency induction heating device, resistance heating by flash butt welding or direct energization may be used. Further, as shown in FIG. 10, when the slits 22 are formed, it is preferable to provide two slits 22 symmetrically with respect to the axis. However, three slits 22 are arranged at a pitch of 120 ° along the circumferential direction and divided into three. Or a slit 22 is further provided to allow four or more divisions. In the case of the joining protective cylinder shown in FIG. 6, the inner peripheral surface 3 a of the flux 3 may have a concave curved surface according to the concave groove 21.
Further, the joining protection cylinder 1 may not have the spiral groove 7.

[0033]

According to the method of joining rods according to the first aspect,
Oxidation and nitridation of the joint can be prevented, whereby the joint is effectively protected, and can be firmly joined in a stable state for a long period of time, thereby providing a high-quality rebar. Also, the flux produces slag,
Effectively prevent biting. For this reason, the work of removing the joining protection cylinder after the joining operation is completed is facilitated, and the working time can be reduced, and the joint can be smoothed.

According to the method for joining rods according to the second aspect, the same effects as those of the first aspect are obtained. Furthermore, in this bonding method, the flux does not absorb moisture, so that oxidation of the bonding portion,
It is possible to reliably prevent nitriding. Moreover, by using the granular flux, it is possible to finish the surface more beautifully, and it is possible to provide a high-quality rebar or the like. In addition, since the protective cylinder is particularly excellent in peelability after the joining operation, productivity can be improved.
Furthermore, it contributes to cost reduction.

According to the third aspect of the present invention, it is possible to provide a high-quality reinforcing bar which is firmly joined for a long time in a stable state. In addition, the work of removing the joining protective cylinder after the joining operation is facilitated, so that the working time can be shortened and the joint can be smoothed.

According to the fourth aspect of the present invention, during the joining step, the inner peripheral portion of the joining protective cylinder does not come into pressure contact with the outer peripheral surface of the rod-shaped body, thereby securely preventing biting. Becomes possible.

According to the fifth aspect of the present invention, if the flux arrangement portion is made to correspond to a pair of abutting surfaces, the flux prevents oxidation and nitridation of the joint portion and prevents biting. Can be effectively prevented,
The required minimum amount of flux is sufficient, and the cost can be reduced. Further, it is possible to effectively prevent the flux from peeling off, and to improve the handleability of the joining protective cylinder. In addition, it is possible to prevent an increase in the outer diameter dimension, thereby preventing an increase in the inner diameter of the coil when using high-frequency induction heating as a heating means, thereby effectively heating the butt end of the rod-shaped body. It is possible to do.

According to the joining protection cylinder of the sixth aspect, the joining protection cylinder can be divided. If the joining protection cylinder is divided before the joining step, the joining protection cylinder can be divided into abutting ends. In addition, even if the jointing process is performed by arranging the joint protective tube at the abutting end without dividing, the joint protective cylinder can be divided, and the joint protective tube from the joint can be divided. Easy removal of the body.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a joining protective cylinder according to the present invention.

FIG. 2 is a half cross-sectional view of the joining protective cylinder in a state in which a coil is wound.

FIG. 3 is a perspective view showing a state in which a coil is wound around the joining protection cylinder.

FIG. 4 is an explanatory view of an embodiment of a method for joining rods according to the present invention.

FIG. 5 is a cross-sectional view showing another embodiment of the joining protective cylinder of the present invention.

FIG. 6 is a cross-sectional view showing another embodiment of the joining protective cylinder of the present invention.

FIG. 7 is a cross-sectional view showing a modification of the protective cylinder of FIG.

FIG. 8 is a sectional view showing another modified example of the protective cylinder of FIG. 6;

FIG. 9 is an explanatory view showing another embodiment of the method for joining rods according to the present invention.

FIGS. 10A and 10B show still another embodiment of the joining protective cylinder of the present invention, wherein FIG. 10A is a plan view and FIG.
FIG. 3 is a sectional view taken along line XX of FIG.

FIG. 11 is a cross-sectional view of a conventional protection cylinder for joining.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Joining protection cylinder 2 Bar-shaped body 3 Flux 5 Inner peripheral surface 19 Butt end 20 Joining part 21 Concave groove 22 Slit D Outer diameter dimension G Gap

 ──────────────────────────────────────────────────続 き Continued on the front page (71) Applicant 501085142 Meito Sangyo Co., Ltd. 92-3, Hashizume, Inuyama, Aichi, Japan (72) Inventor Masao Ushio 4-48, Midoridai, Kawanishi-shi, Hyogo (72) Inventor Matsui Shigetomo 1-5-2 Minatojima Minamicho, Chuo-ku, Kobe City, Hyogo Prefecture Inside the New Industry Creation Research Organization (72) Inventor Hiroshi Shikata 1-2-5 Minatomachi Minatomachi, Chuo-ku, Kobe City, Hyogo Prefecture New Industrial Creation Within the Research Organization (72) Inventor Noboru Nishiyama 1-5-2, Minatojima-minami-cho, Chuo-ku, Kobe City, Hyogo Prefecture Inside the New Industry Creation Research Organization (72) Inventor Yoshikazu Yaginuma 4-3-15 Minamihashimoto, Sagamihara City, Kanagawa Prefecture Japan Electronics Industry Co., Ltd. (72) Inventor Akira Sato 2-36-18 Maekawa, Kawaguchi City, Saitama Prefecture Akira Mineinai Co., Ltd. (72) Inventor Hiroshi Togo Ogi Higashi 1 Komaki City, Aichi Prefecture Eyes 20 address Meito Industry Co., Ltd. in the F-term (reference) 4E067 AA02 BB02 DA17 DB02 DC04 EC05

Claims (6)

[Claims] 1. A pair of rods (2) and (2) are butt-arranged, and both butt ends (19) and (19) are heated.
In a joining method of a rod-shaped body in which both butted ends (19) and (19) are crimped in a heated state, a protective cylinder (1) having a flux (3) on an inner peripheral portion is connected to the two butted ends (19).
(19) and the butt ends (19) (1)
9) A method for joining rods, wherein the temperature of the flux (3) is increased during crimping to generate gas, slag, etc., to protect the joint (20). 2. A pair of rods (2) and (2) are butt-arranged, and both butt ends (19) and (19) are heated.
In the joining method of a rod-shaped body in which both butted ends (19) and (19) are crimped in a heated state, the protective cylinder (1) is placed around the two butted ends (19) and (19), and then the protection is performed. A granular flux (3) is introduced between the cylindrical body (1) and the butting ends (19) and (19), and the above-mentioned butting end (19) is introduced.
(19) A method for joining rods, wherein the temperature of the flux (3) is increased to generate gas, slag, and the like to protect the joint (20) during the pressure bonding. 3. A pair of rods (2) and (2) are butt-arranged, and both butt ends (19) and (19) are heated.
In the joining method of a rod-shaped body for crimping both butted ends (19) and (19) in a heated state, the two butted ends (19)
(19) a joining protective cylinder disposed around;
A cylindrical main body (4) and an inner peripheral surface (5) of the cylindrical main body (4)
And a flux (3) attached to the joint (20), which generates a gas, a slag, etc. by the temperature rise of the flux (3) at the time of press-fitting of the butted ends (19), (19). A protective cylinder for joining, characterized by protecting the joint. 4. A position between the rods (2) and (2) and the inner peripheral surface (5) of the cylindrical body (4) in a state of being disposed around the butted ends (19) and (19). The joint protection cylinder according to claim 3, wherein a gap (G) that is 10 to 25% of an outer diameter (D) of the rod-shaped body (2) is provided. 5. A concave groove (21) is provided on an inner peripheral surface (5) of the cylindrical main body (4), and a flux (3) is arranged in the concave groove (21). The joining protective cylinder according to claim 3 or 4. 6. A plurality of slits (22) along an axial direction.
Is formed.
Any of the protective cylinders for joining.