JPS6138044A - Iron wire clamp method and bolt - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Field of Application J This invention relates to a method for clamping reinforcing bars to a pressure welder in gas pressure welding of steel bars for reinforced concrete, and a tightening bolt thereof.

``Prior Art'' As is well known, most of the joining of reinforcing bars today is done by gas pressure welding, which involves applying pressure to the ends of two reinforcing bars to be joined. The mating part and its surroundings are heated with an oxygen/acetylene flame, and as the temperature rises, upsetting progresses, and the joining is completed when a predetermined bulge is reached.

``Problem to be solved by the invention'' In order to pressure-weld the reinforcing bars, it is necessary for K to strongly grip the reinforcing bars on the support piece of the press-welding device, so the support piece that grips the reinforcing bars is provided with a tightening pole). The reinforcing bar is held between the gripping part of the tightening bolt and the inner wall on the opposite side, and the reinforcing bar is tightened by threading the tightening bolt to integrate the gripping part of the support piece of the pressure welder with the reinforcing bar. The mechanism is such that hydraulic pressure is applied to the movable support piece from the outside to push it forward toward the fixed support piece, and the end faces of the two reinforcing bars to which the movable support piece and the fixed support piece buttons are respectively fixed are pressed against each other.

In this way, the end faces of the reinforcing bars are strengthened (F per nominal cross-sectional area of the reinforcing bars)
, 4~5~'w'') In order to maintain the integrity of the reinforcing bar and the pressure welding device (in other words, to prevent slipping between the reinforcing bar and the tip of the tightening bolt) even when the reinforcing bar is pressed, it is necessary to It is necessary to tighten the tightening bolt with a fairly strong force.
This causes tightening scratches (commonly known as chuck scratches) on the surface of the reinforcing steel. When tensile or bending stress is applied to the joint of two reinforcing bars, these scratches become stress concentration points,
There are many cases where it breaks from this point.

On the other hand, most commercially available rebars these days are made from electric furnaces, and compared to those made from blast furnaces, the quality varies widely and many are more sensitive to notches, making the problem of chuck scratches mentioned above even more acute. This has been viewed as a problem for many years as one of the drawbacks of the pressure welding method.

So, up until now, we have shown A, B, Bl, and C in Figure 1.

As shown in C', D, D', etc., tightening bolts in which the tips of the bolts are shaped like rice grains have been devised and put into practical use in order to reduce stress concentration.

However, in any case, the tip of the tightening bolt bites into the surface of the reinforcing steel, thereby preventing slippage between the reinforcing steel and the bolt due to shear force, which causes stress concentration in the chuck. The problem of scratch formation remains unsolved.

``Means for solving the problem'' By the way, steel bars for reinforced concrete are manufactured according to JIS G3112, and in 7.2.2 of the same, it is stated that ``the edges of hot-rolled deformed steel bars are distributed at approximately constant intervals along the entire length.'' death,
Similarly, 7.2.6 stipulates that ``the height of the top of hot-rolled deformed steel bars shall be as shown in Table 4.''

In reality, the shape of the reinforcing bars can be roughly divided into two types, commonly known as ``bamboo lashes,'' which have ridges perpendicular to the reinforcing bar axis, and those with ridges that are diagonal to the reinforcing bar axis (for example, Decon (product name)).
). The shape of the lid of electric furnace reinforcing bars that has become mainstream these days is bamboo.

Therefore, as a result of actually measuring the shape of two or three commercially available electric furnace rebars, we found that the dimension of the flat part between the ribs was D1.
9-14m for 9-D32 (however, 14cm is common), the height of the handle is approximately 1°5 for D25, and 1.5-1.5m for D32.
It was about 2.5 m (the diameter of the tightening bolt was 25 m).

"Means for Solving the Problems" In view of the above-mentioned circumstances, the present invention provides a structure in which the outer circumferential surface of the tip of the tightening bolt is multi-chamfered into an inclined surface that follows the shape of the rising side surface of the bamboo sash of the reinforcing bar. By inserting this tip between the bamboo ties of the reinforcing bar), when force F is applied between the end faces of the reinforcing bar, the shearing force acting between the reinforcing bar and the tip of the tightening bolt is , the bolt is pressed against the side of the lid as a force,
It is constructed to prevent slipping.

``Function'' As described above, the tip of the tightening bolt of the present invention is not cut into the surface of the reinforcing steel, so it can be flat, and the tightening force is determined by the tightening force when shearing force is applied. There is no need to tighten the bolts as strongly as you don't have to go over the top of the reinforcing bar that the bolts are in contact with. Furthermore, even if the reinforcing bar is tightened strongly, the surface of the reinforcing bar is pressed against the flat tip of the tightening bolt, so there is no possibility of creating a notch that could become a source of stress concentration.

In addition, the part of the bolt tip that rises from the flat part is chamfered appropriately to prevent digging into the base of the bolt when the bolt is pressed against the bolt. Of course.

"Example" Figure 1 A, A', B, B'', C, C', D,
D-, etc. are all examples of the types of tightening bolts used in the conventional chuck method, but the tightening bolts of this method have no restrictions on the shape of the reinforcing bar and the installation of the reinforcing bar. However, this invention can only be applied to bamboo-shaped reinforcing bars. However, the current situation is #
Most of the reinforcing bars are made by electric furnaces, but they are shaped like bamboo spools, so the latter disadvantage of being applicable only to bamboo spools is of great practical importance.

Figures 2A and A', Figures 3 and 4 show a tightening bolt according to the present invention, an explanatory diagram of a reinforcing bar pressure welding process using the tightening bolt, and a movable support piece.

Gripping of reinforcing bars is the same on both the fixed side and the movable side, l is a tightening bolt provided on the support piece that grips the reinforcing bars of the pressure welder, and 2 is a connection formed on the outer peripheral surface of the tip of this tightening bolt (1). It is a sloped surface chamfered to follow the shape of the upright and ascending side surfaces 6 of the bamboo fence 5 on the outer peripheral surface of the reinforcing bar 4 to be reinforced, and its end surface is a flat surface 3.

This tightening bolt 1 is inserted between the bamboo fences 5 and 5, and its rounded surface 3 is brought into contact with the outer circumferential surface of the reinforcing bar 4. As a result, the inclined surface 2 of the tightening bolt 1 comes into contact with the rising side surface 6 of the bamboo sash 5 of the reinforcing bar 4, and no further slip occurs. In this way, the reinforcing bars and their support pieces (movable support piece 7)
and the fixed support piece 8) are integrated, the hydraulic pressure of the hydraulic system 9 is applied from the outside to the movable support piece 7 side to press the reinforcing bar 4ft of the movable support piece 7 against the reinforcing bar 41 of the fixed support piece 8, and the abutment is made. Both reinforcing bars 4 and 4' are welded under gas pressure by heating the part with an oxygen e-acetylene gas flame. When the welding is completed, the fire is extinguished and the welded part is cooled to complete the work.

"Effect J" As stated above, the pressure welding method of the present invention has the extremely important advantage of reliably preventing the formation of chuck scratches on the outer circumferential surface of reinforcing bars. The reliability of gas pressure welding joints can be further improved by simply changing the shape of the tip of the tightening bolt to a simpler shape than that of the conventional main type, without requiring any changes. It's big.

[Brief explanation of drawings]

Figures 1A and A1 are a front view and an end view of a conventional tightening bolt, Figures 1B and B' are a front view and an end view of another example of a conventional tightening bolt, and Figures 1C and C1 are a front view and an end view of a conventional tightening bolt. A front view and an end view of another example of the conventional tightening bolt, FIGS. 2A and A1 are a front view and an end view of the tightening bolt of the present invention, and FIG. FIG. 4, which is an explanatory diagram of the press-contacting method, is a side view of the movable support piece. 1: Tightening bolt 2: Chamfered inclined surface of the tightening bolt 3: Flat surface 414' of the tightening bolt: Reinforcing bar 5: Bamboo siding of movable reinforcing bar 6: Rising side of the bamboo siding 7: Movable support piece 8: Fixed support Piece 9: Hydraulic device patent applicant Japan Gas Pressure Welding Co., Ltd. Agent Shigema Inoue ;・,′・2nd
Figure A Figure 2 A' Procedural amendment 1. Indication of the case 1982 Special Application No. 159290 Nippon Gas Pressure Welding Co., Ltd. 4, Agent 5, Date of amendment order November 27, 1980 (shipment date) 7, Contents of amendment As shown in the attached sheet , amend the claims as follows. (1) One of the two reinforcing bars to be welded is attached to a fixed piece and the other to a movable piece, and by applying hydraulic pressure to the movable piece and pushing the movable piece towards the fixed piece, a force is applied between the end faces of the two reinforcing bars. In the gas pressure welding method, which involves applying pressure and heating the mating part with an acetylene flame in oxygen, the reinforcing bar clamp tightening bolt attached to the movable piece is inserted between the gaps of the reinforcing bars. A method for clamping reinforcing bars, characterized in that the shearing force exerted between the reinforcing bars and the tip end of the tightening bolt is supported by the reinforcing bars by means of the pressing between the end faces of the reinforcing bars. (2) A tightening bolt that is installed in the part of the support piece of the pressure welder that grips the reinforcing bars, and has an inclined surface chamfered on the outer circumferential surface of the tip part so as to follow the shape of the rising surface of the bamboo fence of the reinforcing bars. 2. In the second line from the bottom of page 6 of the specification, the phrase [...e electric furnace steel bars,'' is amended to read, "...electric furnace steel bars." 3. Attached drawings [Figure 1 A'J has been changed to ``Figure 1 B,''
"Figure B" to "Figure 1 C" and "Figure 1 B'J" to "Figure 1 D."
", "Fig. 1 C" to "Fig. 1 E", "Fig. 1 C'J
to "Fig. 1 F", "Fig. 1 D" to "Fig. 1 G", "
Change Figure 1 D'J to ``Figure 1 H'' and ``Figure 2 AI J to ``Figure 1 H.''
Figure 2B" respectively. FIG. 3 is an explanatory diagram of a method of press-contacting a movable reinforcing bar to a fixed reinforcing bar according to the present invention, and FIG. 4 is a side view of a movable support piece. l: Tightening bolt 2: Chamfered inclined surface of the tightening bolt 3: Flat surface of the tightening port 4 g4': Reinforcement bar 5: Bamboo sash of movable reinforcing bar 6: Rising side of the bamboo sash 7: Movable support piece 8: Fixed support piece 9: Hydraulic system

Claims (2)

[Claims] (1) Attach one of the two reinforcing bars to be pressure-welded to a fixed piece and the other to a movable piece, and apply hydraulic pressure to the movable piece to push the movable piece toward the fixed piece to apply pressure between the end faces of the two reinforcing bars. In the gas pressure welding method, which involves applying pressure and heating the mating part with an oxygen/acetylene flame, the reinforcing bars are joined by flattening the tip of the reinforcing bar clamp bolt attached to the movable piece mentioned above. A method for clamping reinforcing bars, which comprises inserting the reinforcing bars between the ties and supporting the shearing force acting between the reinforcing bars and the tip end of the tightening bolt due to the pressing force between the ends of the reinforcing bars, using the ties of the reinforcing bars. (2) The support piece of the pressure welding device is provided at the part that grips the reinforcing bars, and the outer circumferential surface of the tip part is chamfered to follow the shape of the rising surface of the bamboo fence of the reinforcing bars, and the end face is provided with a flat part. Tightening bolt.