JPH0739040B2 - Jig for rebar welding without backing metal - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a jig for shielding when welding reinforcing bars to each other, and in particular, a backing metal is unnecessary and a weight is reduced as a whole. It is characterized by

[Conventional technology]

One of the methods for connecting reinforcing bars at a construction site or the like is known as a so-called enclosing method. This is done by covering the welded place with a cover and filling it with shielding gas. The cover is attached to the abutted rebars so that the cover is sandwiched from both lateral sides, and welding is performed from a window provided in the cover.

Specifically, one of the covers (the first cover)
Has a hose of shield gas and a window facing the weld,
Semicircular cutouts for sandwiching the reinforcing bars are provided on both sides, and a jet port for jetting gas inside and a jet port for forming an air screen are formed along the window.
The other cover (referred to as the second cover) has a semicircular cutout at the same position as the cutout of the first cover, and the inner surface has a semicylindrical backing with the same shape as this cutout. Gold is formed so as to face the window of the first cover. Then, the first cover and the second cover are fixed to the reinforcing bar with a fastener such as a screw, and welded from the window as described above.

As another method, a method using a tubular joint is known. This is because a pipe that fits the outer shape of the reinforcing bar is cut into an appropriate length, or an opening is provided on the side surface of a steel plate that is bent and bent according to the outer shape of the reinforcing bar. The cover is covered and the welding rod is inserted through the opening to weld the reinforcing bars.

[Problems to be Solved by the Invention]

However, in the above-mentioned enclosing method, since the backing metal is used for welding, the diameter of the reinforcing bar is increased in the welded portion. The combined cover was supported with one hand, and the window of the cover was accurately aligned with the groove of the reinforcing bar while the other hand tightened the screws. Moreover, the window of the cover is not so large to enhance the shielding effect, and,
Since the route interval is usually about 14 mm at the maximum, the work of carrying out delicate positioning with a heavy steel cover with one hand was very fatigued. Further, since a large number of covers are required to carry out the welding work continuously, the total weight is squeezed and the transportation and the like becomes a heavy labor.

On the other hand, in the case of the pipe type joint, the gas shielding effect was not sufficient, and good welding was not obtained due to the mixing of oxygen and the reliability could not be improved. In addition, since the joint forms the remaining step at the welded part, a concrete column is prepared in advance, and when the method of pouring concrete into the hollow part through the reinforcing bar through the hollow part formed in the concrete column from the top, the joint part is As an obstacle, concrete did not spread over the entire hollow part, or the diameter of the hollow part had to be made wider. In addition, when the pipe or backing metal is attached to the outer circumference of the reinforcing bar, when attaching the hoop bar that fixes the columnar reinforcing bar from the outside, it cannot move along the reinforcing bar and the work progresses smoothly. In addition, the welded part cannot be visually inspected, and the work is complicated because it is inspected by a method such as ultrasonic flaw detection.If such inspection is omitted, the reliability is poor and the allowable strength is low. I had to do it.

[Means for Solving the Problems]

In order to solve the above problems, the present invention has a reinforcing bar welding jig configured as follows. That is, the first cover and the second cover are detachably made from ceramics, and the side surfaces of the first cover and the second cover are provided with a semicircular cutout that is opened equal to the diameter of the reinforcing bar when assembled, and A window formed in the first cover so that the welding rod can be inserted and carried by facing the welded portion, an inlet for connecting a shield gas introducing hose, and an opening surface of the window communicating with the inlet. A gas ejection port provided in an edge portion of the window that opens in a parallel direction and a gas ejection port that communicates with the introduction port and ejects gas toward the inside are provided, while the second cover has the cutting port. Thus, the welding jig was formed with a semi-cylindrical inner surface formed so as to be continuous with the notch and having a diameter substantially equal to the outer diameter of the reinforcing bar.

[Action]

Reinforcing bars can be welded and connected without using a backing metal. for that reason,
Does not increase the outer diameter of the rebar when connected. Since the overall weight can be reduced, the work during transportation and installation can be facilitated. Since a pipe or the like is not inserted during the assembling of the reinforcing bar, the assembling of the reinforcing bar can proceed regardless of the welding work, and the work flow can be smoothed.
Since it is possible to reliably prevent the mixing of oxygen and the like into the welded portion and the outflow of the molten metal to the outside, a good welding result can be obtained and the strength and reliability can be improved.

〔Example〕

An embodiment of a welding jig according to the present invention will be described below with reference to FIGS. 1 and 2.

The jig 1 is made of ceramic and is composed of a first cover 2 and a second cover 4. The first cover 2 is
An inlet 6 for introducing gas is formed on the lower surface, a window 8 for supplying the wire is formed on the front surface, and a semicircular cutout 2 having the same diameter as the reinforcing bar 10 is formed on the upper and lower surfaces. Further, as shown in FIG. 2, an ejection port 14 that opens toward the second cover 4, an ejection port 16 for the air curtain that opens along the window 8 and a stopper 18 are provided inside. The introduction port 6 is connected to a carbon dioxide gas cylinder or the like (not shown), and the ejection port 14 and the ejection port 16 communicate with the introduction port 6 inside the first cover 2. The window 8 is the first cover 2
It is formed almost at the center of the and has a sufficient width for inserting a welding rod and carrying it inside. The stopper 18 has a spherical body 20 springed on the side surface at a right angle to the side surface where the notch 12 is provided.
It is urged by 22 and a part of it is provided so that it can project and retract inside.

The second cover 4 is shaped to fit inside the first cover 2 and has an inner surface formed in a semi-cylindrical shape along the outer surface of the reinforcing bar 10 as shown in FIG. Arms 26 each having a recess 24 that fits in are provided at positions corresponding to the stoppers 18.

Next, the operation of the jig 1 will be described. The reinforcing bar 10 to be welded here is as follows. One of the reinforcing bars 10 is vertically embedded in the concrete and its end projects upward, and the reinforcing bars 10 of the same diameter are welded to the upper part of the reinforcing bar 10, and a fixing jig (not shown) is used before welding. ) Is fixed in. The fixing jig is configured such that the intervals between the sandwiching parts sandwiching the reinforcing bar 10 at both ends can be adjusted by screws, and the reinforcing bars 10 fixed by the sandwiching parts are set to a predetermined route interval. After fixing the two reinforcing bars 10 in this manner, the first cover 2 and the second cover 4 are sandwiched from the front and rear in the welded portion, and the stopper 18 is fitted into the recess 24 of the arm 26 to attach the jig 1. Then, a clip or the like (not shown) sandwiching the reinforcing bar 10 is further attached to the lower portion of the jig 1 to support the jig 1 so as not to drop. The gas hose is opened and carbon dioxide gas is introduced into the jig 1 to create a carbon dioxide atmosphere inside the jig 1 and welding is performed through the window 8. Welding is performed by arc welding, and the welding rod is a window 8.
The welding metal is directly piled up on the inner surface of the semi-cylindrical shape of the second cover 4 and the space between the reinforcing bars 10 is welded.

Therefore, according to the jig 1, a backing metal is not required,
Moreover, since the inner surface of the second cover 4 is formed along the diameter of the reinforcing bar 10, the welded portion can have the same outer shape as the reinforcing bar 10. Therefore, the cost of the backing metal can be reduced, the hoop reinforcement can be easily attached, and when the concrete column is covered with the reinforcing bar 10 and the concrete is poured around the reinforcing bar 10, the concrete can be poured smoothly and surely. it can. In addition, since the welding trace can be directly visually observed from the appearance, when a crack, a welding defect, or the like can be immediately confirmed, it is possible to perform good welding with high reliability. Further, since it is more mass-producible than steel and can be manufactured in accordance with various kinds of reinforcing bar diameters, it is possible to improve gas shielding properties and prevent molten metal from flowing down through gaps. Further, in the first cover 2, the gas introduction port 6 and the air curtain ejection port are provided.
16. Since the gas ejection port 14 to the inside is formed, the welding work can be immediately started simply by mounting the first cover 2 on the second cover 4, which is efficient. Since the weight is reduced, the work of attaching to the reinforcing bar 10 is facilitated and the work can be performed efficiently. In addition, if a core is placed inside the jig 1 and only the core can be replaced when it is damaged, a jig with reduced cost can be provided.

In the above embodiment, the welding of the vertical reinforcing bar 10 has been described, but the present invention is not limited to this, and the present invention can be applied even when the reinforcing bar 10 is set in the horizontal direction or another oblique direction. Further, in the above example, the semi-cylindrical inner surface of the second cover 4 is formed up to the end portion, but the present invention is not limited to this, and the semi-cylindrical inner surface is formed to have a sufficient length to cover the root interval. A semicircular cutout may be formed on the side surface of the cover 4.

In addition, the commercially available rebar 10 is allowed to have a diameter difference of several millimeters depending on the diameter.
Even if the rebar 10 is attached, the rebar 10 may not come into direct contact with the second cover 4. As a means for solving this, as shown in FIG. 3, the spring is turned toward the first cover 2 and toward the second cover 4.
A push pin 32 biased at 30 is provided. With this configuration, when the jig 1 is attached to the reinforcing bar 10, the push pin 32 is
Since 10 can be pressed and kept in contact with the inner surface of the second cover 4, the finish of the welded portion can be improved.

〔The invention's effect〕

According to the jig of the present invention, since it is made of ceramic, it is not necessary to provide a backing metal for preventing rapid cooling of a welded part, which is a separate member in the related art. The flow of concrete is good, the appearance can be visually inspected easily, and the accuracy of ultrasonic inspection can be improved, and the reliability of the joint can be improved. In addition, since the jig can be accurately attached to the reinforcing bar, the gap can be reduced, and the inflow of oxygen and the outflow of the molten metal can be prevented, and good welding can be performed in a short time. Further, since the gas inlet, the air curtain outlet, and the gas outlet to the inside are formed in the first cover 2, the welding work can be performed immediately by mounting the first cover on the second cover. It is efficient. Since it is not necessary to incorporate work other than assembling work into the work for assembling the reinforcing bar, such as inserting a pipe-shaped joint into the reinforcing bar, the setup and flow of the work for assembling and welding the reinforcing bar can be improved. Further, since it is light in weight and has good workability and good moldability, it is possible to inexpensively mass-produce jigs adapted to respective reinforcing bars having different diameters.

[Brief description of drawings]

1 is a perspective view showing a jig, FIG. 2 is a sectional view of the jig, and FIG. 3 is a sectional view showing another embodiment. In the drawings 1 ... Jig, 2 ... First cover, 4 ... Second cover, 6
…… Inlet, 8 …… Window, 10 …… Reinforcing bar, 12 …… Notch,
14, 16 ... Spout, 18 ... Stopper, 20 ... Sphere, 22 ...
… Spring, 24 …… recess, 26 …… arm, 30 …… spring, 32 …… push pin.

Claims (1)

[Claims] Claim: What is claimed is: 1. A first cover and a second cover which is detachably attached to the first cover, assembled from both sides of the reinforcing bar, and covers the welded part of the reinforcing bar during welding at a construction site such as a construction site. In the tool, semi-circular cutouts are provided on the side surfaces of the first cover and the second cover, the semi-circle notch opening equal to the diameter of the reinforcing bar when assembled, and the welding rod is inserted into the first cover facing the welding portion. A window that can be carried, an introduction port to which a hose for introducing a shielding gas is connected, and a gas ejection port provided at the edge of the window that is in communication with the introduction port and opens in a direction parallel to the opening surface of the window. And a gas ejection port communicating with the introduction port for ejecting gas toward the inside, and the second cover has a semi-cylindrical inner surface formed to be approximately equal to the outer diameter of the reinforcing bar along the notch. , Reinforcing rod welding jig made of ceramic.