JPS6142438A - Method for reducing sleeve of turnbuckle type deformed bar joint - Google Patents

Abstract

PURPOSE:To obtain the large reduction of an area a small working force by reducing a sleeve in stages using plural piercing dies. CONSTITUTION:The first piercing die 9 reduces sleeves 3, 4 preliminarily, and the second piercing die 10 reduced sleeves 3, 4 finally. That is, when sleeves 3, 4 are pressed by an oil pressure press 8, the sleeves 3, 4 are reduced at the rate of a half of reduction of the area to be finally obtained by the first and second piercing dies 9, 10, and as a result, the sleeves 3, 4 are reduced at reduction of the area to be desired finally.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for connecting a deformed reinforcing bar and a sleeve in a turnbuckle type deformed reinforcing bar joint used in concrete foundation work and the like.

As shown in FIGS. 2 and 3 with a conventional turnbuckle type deformed reinforcing bar joint and J-, deformed reinforcing bar receivers 3a + 4a fit the ends of deformed irons 61.2 to be connected to each other. on one end side, and a female thread part 3b in the opposite direction on the other end side.

4b and these sleeves 3.4
The female threaded parts 3b and 4b have opposite male threaded parts 5a and 5be on the left and right sides, and these male threaded parts 5a
, 5b, and a bolt rod 5 with a torque control shaft 5ci protruding from the approximate center between them, and the torque control shaft 5c? The torque control shaft 5C is attached to the outer periphery of the central part of the bolt rod 5 while being inserted into the bearing groove 6a formed in the axial direction of the inner peripheral surface, and the torque control shaft 5C is damaged when a tightening torque higher than necessary is applied. A tightening ring 6 is formed by reducing the diameter of the sleeves 3 and 4, and protrusions 1a, 2&? A turnbuckle type modified reinforcing bar joint 7ri is known (Japanese Patent Application No. 53-35031) in which a sleeve 3.4 is attached to one end of the modified reinforcing bars 1 and 2 by biting.

Conventionally, a hydraulic press 8 and one hole die 9 have been used to reduce the diameter of the sleeve 3.4, as shown in FIG.

Problems to be Solved by the Invention Sleeve 3.4f using hydraulic press 8 and hole die 9
: In the so-called punching method to reduce the diameter, the working force (pushing stress) ri is determined by the following approximate formula.

σ=kfm[:(1+ff//j)fl-(1-r)P
/"S+(4/3+'3)α)+σb(lr)μ/a P"At・σHB=Ao"b, r=(As At
)/A.

However, P: Pulling force, B: Reverse tension, A0: Cross-sectional area before pulling, A1: Cross-sectional area after pulling, kfn+: Average deformation resistance of the pulled material, σ: Pulling stress, σb: Reverse tension stress, α
: Die half angle, μ: Friction coefficient between material and die, r: Area reduction rate.

Therefore, if we try to increase the cross-sectional reduction rate of the sleeve 3.4, the processing force (pushing force) must be increased in proportion to this, and if the cross-sectional reduction rate is increased, the hydraulic pressure There was a problem that the press 8 could not be processed.

Means to solve the problem The diameter of the sleeve is reduced in stages and continuously by using multiple hole dies with different large and small hole diameters. By reducing the area reduction rate at , it is possible to finally obtain a large area reduction rate.

EXAMPLE Next, the present invention will be explained with reference to FIG. In the figure 9
and 10 are first and second hole dies for reducing the diameter of the sleeves 3 and 4 in stages. The first hole die 9 is used to preliminarily reduce the diameter of the sleeve 3.4, and the second hole die 10 is used to finally reduce the diameter of the sleeve 3,4. The area reduction rate of 4 is @2
The cross-section reduction rate of the sleeve 3.4 in the hole die 10 is set to approximately 1/2.

Therefore, when the sleeves 3.4't- are pressed by the hydraulic press 8, these sleeves 3, 4 are pressed against the first. Second hole die 9.1
0 and 1/1 of the area reduction rate to be finally obtained.
The diameter of the sleeve 3.4 is reduced at a rate of 2, and as a result, the diameter of the sleeve 3.4 is reduced at the desired cross-section reduction rate. We have shown the case where the diameter of the sleeve is reduced in two stages using
The three-stage TR may be reduced in diameter to the fourth stage.

Effects of the Invention Since the diameter of the sleeve is reduced in stages using multiple hole dies, the area reduction rate at each stage is reduced and a large area reduction rate is finally obtained, which means a small machining force. (pushing force) makes it possible to obtain a large reduction in area.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing the case where two hole dies with different large and small hole diameters are used to reduce the diameter of the sleeve, Figure 2 is a cross-sectional view of a deformed reinforcing bar joint, and Figure 3 is a cross-sectional view of a deformed rebar joint. FIG. 4 is a sectional view showing a conventional sleeve diameter reduction method. 1.2... Deformed reinforcing bar, 3, 4... Sleeve, 3a,
4a... Deformed reinforcing bar receiving part, 3b, 4b... Oxidized screw part,
5... Bolt rod, 5a, 5b... Male thread part, 5c.
...Torque control 411.6...Tightening ring,
7...Turnbuckle type deformed reinforcing bar joint, 8...Hydraulic press, 9.10... Hole die.

Claims (1)

[Claims] (1) One end has deformed rebar receivers (3a) and (4a) that fit the ends of deformed rebars (1) and (2) to be connected to each other, and the other end has deformed rebar receivers (3a) and (4a) in the opposite direction. Female thread part (3b), (4b
), and male threaded parts (5a), (5b) in opposite directions that are screwed into the female threaded parts (3b), (4b) of these sleeves (3), (4). ) on the left and right sides, and a bolt rod (5) having the sleeve (
By reducing the diameter of sleeves (3) and (4), these sleeves (3) and (4) are
) is attached to one end of the deformed reinforcing bars (1) and (2) in a turnbuckle type deformed reinforcing bar joint (7). A method for punching and reducing the diameter of a sleeve, which is carried out stepwise and continuously using hole dies (9), (10), etc.