JPS5832018B2 - Manufacturing method of bolts for fastening temporary frames - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a temporary frame fastening bolt for temporarily fastening a formwork to be assembled when pouring fresh concrete.

As shown in Fig. 6, the conventional bolt for fastening a temporary frame is formed by integrally molding a screw shaft 31 at the tip of a hollow cylindrical body 30. The stopper body 32 is fitted into one piece, applied to the concrete formwork 33, and the screw shaft 31 protrudes to the outside of the formwork.
is screwed with a nut 34, and since the two objects are formed separately, it takes time and effort to manufacture, which increases costs, and it is inevitable that assembly and disassembly work will also be time-consuming. It was something.

For this reason, it is conceivable to form the two objects into one by forging, but since the mass is large, the durability of the die becomes an issue when forming by forging, and it is subject to a strong punching force. As a result, the die mold is subject to severe wear and tear, and in addition, the mass is large, requiring a large amount of material, and the weight is also high, making it generally impractical.

Therefore, the inventor of the present invention has succeeded in integrally molding the locking flange on the cylindrical part by forging a thin and flat piece, which allows the forging to be carried out easily, suppresses the increase in mass, and reduces the weight. This eliminates the need to make the die mold particularly strong, thereby solving the above-mentioned conventional drawbacks at once.

Therefore, the present invention is characterized in that a conical base is forged between the cylindrical part and the square part in the intermediate preliminary heading step, and then flattened in the next step to form a thin disc-shaped locking collar. The second invention is further characterized in that the disc body is pressed and bent into a bowl shape in the final step so that the square part of the base of the shaft rod is enclosed in the hollow interior of the bowl-shaped locking flange. It is something to do.

The details will be explained below with reference to the embodiments shown in the drawings.

Fig. 1 shows the main parts of the apparatus for carrying out the method of the present invention. In the front are multiple punches attached to a moving platform that moves forward and backward by the operation of a moving ram? , 8,9°10.11 are provided so as to face each other.

The material 12 is obtained by cutting a continuous round bar material made of metal into predetermined dimensions in a cutting process, and is gripped by a chuck (not shown) and transported to the front part of the die 2, which is the first step.

In the first step, a conical taper step 2b is formed in the die hole 2a.
is provided, and when the material 12 is hit with the punch 7 and press-fitted therein, the material is squeezed by the single-step taper portion 2b, so that the material becomes a shaft rod 12c having a conical portion 12b at the tip of the body portion 12a.
It is a one-piece projecting structure.

In the second step, the mold hole 3a of the die 3 has a square hole bottom 3b for forming a square part, and a piercing tool 8b is provided at the center of the cylindrical punch 8a on the punch 8 side, and the punch When the material obtained in the previous step is supplied just before the die 3 and is strongly hit with the punch 8 and press-fitted into the die hole 3a, a recess 12d is formed at the end of the body 12a, and at the same time the body 12a and the shaft The conical portion 12b between the rod 12c is transformed into a hexagonal or other square portion 12e.

In the third step, the material obtained in the previous step is press-fitted into the die hole 4a with the shaft portion 12c and square portion 12e uprooted using the punch 9, and a conical hole 9a is formed on the punch 9 side. When the body part 12a of the material is struck with a cylindrical punch 9b and a piercing tool 9c protruding into the center thereof, a deeper recess 12h is formed, and at the same time, the middle part of the body part 12a protrudes outward by an amount corresponding to the recess 12h, forming a cylinder. Part 12f and square part 1
A conical stem root portion 12g is formed between the stem and the stem 2e.

In the fourth step, as in the previous step, the shaft portion 1 of the material is inserted into the die hole 5a.
Punch 10 with 2c and square part 12e upturned.
Press the material in.

On the punch 10 side, a hollow punch 10c having a die hole 10a for forming a cylindrical portion and an end face 10b for forming a disk by crushing, and a piercing tool 10d are integrally assembled at the center of the punch. When the material obtained in the previous step is pressed into the die hole 5a and hammered, the end surface 10b of the hollow punch 10c and the die end surface 5b form the conical stem root 1.
2g is flattened into a thin disk-shaped locking collar 12i, and the cylindrical portion 12f is also formed into a predetermined shape.

The disk-shaped locking flange 12i formed in this way is made thin enough to be bent by forging and large enough to function as a locking flange.

This fourth step may be the final step, but if you provide another step and make it the final step, the shaft portion 12c and the square portion 12e are placed in the die-shaped hole 6a in the same step. The cylindrical punch 1 is press-fitted with a punch 11 into a spherical receiving mold 6b that protrudes into a hemispherical shape.
The spherical concave portion 11b of 1a is pressed into a bowl shape and bent to form a bowl-shaped locking collar 12, thereby forming a square portion 12 at the base of the shaft rod.
e is surrounded by a bowl-shaped hollow interior 12p.

The forged product obtained in this way is then attached to the shaft 12c.
A screw 12m is separately machined in the recess 12h, and a female thread 12n is machined in the recess 12h, respectively, and these are used as fastening fittings for temporary concrete frames, as shown in FIGS. 3 and 4.

In the figure, 13 is a temporary concrete frame, 14 is a threaded rod connecting the left and right sides, and 15 is a nut.

As described above, this invention forms a conical stem root between the cylindrical part and the square part in the intermediate preliminary heading process, and crushes it flat in the next process to form a thin disc-shaped locking collar. In this case, in the final step, the disc is pressed and bent into a bowl shape so that the square part of the base of the shaft rod is enclosed in the hollow interior. Although it is large enough to be integrally molded with the part, the wall thickness is thin, so the forging process can be carried out easily and reliably, and there is no need to apply excessive force to dies or punches, so the mold etc. It is easy to put into practice as it does not need to be made strong and a normal one will suffice, and the product is also lightweight and requires less material, so it is highly economical and can be implemented at low cost.

Furthermore, depending on the shape of the die and punch in the fourth step, the disc-shaped locking flange 12i can be easily pressed into any suitable shape or size, such as a slightly curved inner plate shape. It is possible.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a cross-sectional plan view showing the main parts of an apparatus for carrying out the method of the present invention, and FIG. 2 is a plan view showing the order of pressing and deformation of the material in each process from cutting. A portion of each is shown in cross section. 3 and 4 are cross-sectional views showing a temporary concrete frame tightening section, FIG. 5 is a front view of a forged product, and FIG. 6 is a cross-sectional view of a conventional concrete temporary frame tightening section. 2-6... Dice, 7-11... Punch, 12... Material, 12c... Axis rod,
12e... Square part, 12f... Cylindrical part, 12g... Conical stem root, 12h...
Recessed portion, 12i...Disk-shaped locking collar, 12k...
... Bowl-shaped locking tsuba.

Claims (1)

[Scope of Claims] 1. A method for heading a bolt, in which a shaft rod with a rectangular base and a cylindrical part with a flang and a recessed part as a screw hole are integrally molded at the other end, comprising: A temporary frame fastening bolt characterized by forging a conical base between the cylindrical part and the square part in the intermediate preliminary heading process, and crushing it flat in the next process to form a thin disc-shaped locking collar. manufacturing method. 2. A method for forging a bolt in which a shaft rod with a square root at the tip and a cylindrical part with a flang having a concave portion for a screw hole are integrally formed at the other end, and in the intermediate preliminary heading step, A conical base is forged between the cylindrical part and the square part, and in the next process it is flattened to form a thin disc-shaped locking collar, and in the final process, the disc body is pressed and bent into a bowl shape. A method for manufacturing a bolt for fastening a temporary frame, characterized in that the square part of the base of the shaft rod is formed so as to be surrounded by the hollow interior of the bowl-shaped locking collar.