JPH0978766A - Screw joint for bar steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw joint for bar steel having the excellent workability, profitability and joint rigidity, which can connect bar steels even in the case where a phase difference exists between a screw of each bar steel. SOLUTION: A male screw is provided in a connecting end of a pair of bar steels 1, 1a to be connected, and an auxiliary bar steel 1b having a male screw is arranged between these bar steels 1, 1a. One bar steel 1 and the auxiliary bar steel 1b are connected by a coupler 4 having a female screw in the inner peripheral part thereof, and the auxiliary bar steel 1b and the other bar steel 1a are connected by a coupler 4 having a female screw in the inner peripheral part thereof. Width of a screw groove forming the female screw of the coupler 4 is formed larger in relation to the width of the male screw of the bar steel so that a gap to be generated between the female screw and the male screw becomes 1/4 of the screw pitch or more. The gap of the couplers 4 of two positions respectively absorbs a phase difference of the screw by 1/4 of the rotation, and the bars steels can be connected even in the case where any degree of phase difference exist between the male screws of the bar steels 1, 1a to be connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel bar threaded joint formed by connecting a pair of steel bars each having a male thread at a connection end thereof with a coupler having an internal thread at an inner peripheral portion thereof.

[0002]

2. Description of the Related Art As joints for reinforcing bars, deformed reinforcing bars and the like, there are known screw joints which are joined by a coupler in a screw manner (see JP-B-55-44101 and JP-B-52-7443).

FIG. 7 shows an example of such a threaded joint. A pair of steel bars 1 to be connected to both ends of the coupler 4 are shown in FIG.
After screwing 1a, through the grout injection hole 7 through the grout material 6
Is injected, and two steel bars 1, 1 are produced by solidifying the grout material 6.
a is connected.

FIG. 8 shows an example of a reinforcing bar joint by a sleeve system. After inserting a pair of steel bars 1 and 1a to be connected to both ends of a sleeve 9, a grout material 6 is injected.
By solidifying the grout material 6, the two steel bars 1 and 1a are connected.

FIG. 9 shows an example of a reinforcing bar joint by the double torque system. A pair of steel bars 1 and 1a to be connected to both ends of the coupler 4 are screwed together, and lock nuts 5 are set at both ends of the coupler 4. Then, a predetermined torque is applied and tightened to connect the two steel bars 1 and 1a. The coupler 4 is composed of two members that are screwed together by screws 10.
When the screws of the two steel bars 1 and 1a have a phase difference, the screw 11 of the coupler 4 can be used for adjustment.

FIG. 10 shows an example of a rebar joint of the free joint method (see Japanese Patent Laid-Open No. 6-158783), and a pair of steel bars 1 to be connected to both ends of the coupler 4.
After screwing 1a, through the grout injection hole 7 through the grout material 6
Is injected, and two steel bars 1, 1 are produced by solidifying the grout material 6.
a is connected. Further, in the coupler 4, the gap between the female screw 3 on the inner periphery and the male screw 2 of the steel bar 1 is 1 / the pitch of the screw.
Even if there are two or more and there is a phase difference between the screws of the two steel bars 1 and 1a, the phase difference can be absorbed and connection can be made.

[0007] In addition, as a joint for a steel bar, one made by crimping or welding is known.

[0008]

In the joint shown in FIG. 7, when the steel bars 1 and 1a to be connected are fixed in advance and the screws have a phase difference, the coupler 4 and the steel bars 1 and 1a are screwed together. Is impossible, and the steel bars 1 and 1a cannot be connected to each other.

In the joint shown in FIG. 8, the sleeve 9 needs to have a certain length and a certain thickness, and the dimensions have been devised.

In the joint shown in FIG. 9, the coupler 4 having a complicated structure is used.
Therefore, the cost is high.

In the joint shown in FIG. 10, the coupler 4 needs to have a certain length, and its dimensions are devised. Also, since there is a large amount of backlash, there is concern about strength depending on conditions.

[0012] In addition, crimping and welding require a large facility during construction, which causes a problem in workability.

The present invention solves the above-mentioned problems in the prior art, and in particular, even when the steel bars embedded in the precast concrete member are fixed in advance and the screws to be connected have a phase difference, they are connected. It is an object of the present invention to provide a steel bar threaded joint that is capable of performing and is excellent in workability and economy.

[0014]

The outline of the present invention will be described below with reference to the accompanying drawings.

In the invention according to claim 1 of the present application, a pair of steel bars 1 and 1a to be connected are provided with male threads 2 at their connection ends, and an auxiliary steel bar 1b having male threads 2 is arranged between these steel bars 1 and 1a. Then, the respective steel bars 1 and 1a and the auxiliary steel bar 1b are connected to each other by two couplers 4 each having an internal thread 3 which is screwed into the male thread 2 of the respective steel bars 1 and 1a and the auxiliary steel bar 1b. The axial gap g between the male screw 2 and the male screw 2 is ¼ or more of the screw pitch p.

Here, the gap is the female screw 3 of the coupler 4.
And the length of the axial gap generated between the steel bars 1 and 1a and the male screw 2 of the auxiliary steel bar 1b. The gap may be formed on one side or both sides of the thread or groove, but when it is formed on both sides, the total length shall be considered.

In principle, it is desirable that the upper limit of the gap g be as small as possible within a range smaller than ½ of the screw pitch p in order to reduce play in the joint portion.

Further, the male threads 2 of the steel bars 1 and 1a and the auxiliary steel bar 1b are not limited to being provided only at the connecting end portions,
For example, in the case of a deformed steel bar having a screw protrusion, it may be provided over the entire length.

The invention according to claim 2 relates to the case where the screw pitch is different for any or all of each coupler 4 and each of the steel bars 1 and 1a and the auxiliary steel bar 1b.
The gap between the female screw 3 of each coupler 4 and the male screw 2 of each steel bar 1, 1a and auxiliary steel bar 1b is defined to be ¼ or more of any minimum screw pitch.

That is, the present invention is also applied to the case where the steel bars 1 and 1a to be connected or the auxiliary steel bars 1b, or the steel bars 1 and 1a and the auxiliary steel bars 1b and the two couplers 4 have different screw pitches. It is possible, and in that case, by setting the gap to ¼ or more of any minimum screw pitch, connection can be made for any phase difference.

Claim 3 claims that each coupler 4 and each steel bar 1, 1
This is limited to the case where the grout material 6 is filled in the gap formed between the a and the auxiliary steel bar 1b. Since the steel bars 1 and 1a and the auxiliary steel bar 1b and the coupler 4 are integrated, high joint rigidity can be obtained.

Claim 4 claims that each coupler 4 and each steel bar 1, 1
The case where the a and the auxiliary steel bar 1b are screwed together and then fixed by tightening the nuts 5 from both ends of the coupler 4 is limited.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an outline of a connecting method in a threaded joint of the present invention, FIG. 2 shows a principle of a steel bar threaded joint of the present invention, and FIG. 3 shows a relationship between a thread pitch p and a gap g. It is a thing.

According to the present invention, in a steel bar threaded joint,
The gap g is set to a length of 1/4 or more of the screw pitch p (1
/ 4 or more, and it is desirable to be as small as possible), and the pair of steel bars 1 and 1a to be connected is joined using the two couplers 4 and the auxiliary steel bar 1b.

That is, for example, the female screw 3 on the inner peripheral portion of one coupler 4 is screwed into the male screw 2 of one steel bar 1, and the auxiliary steel bar 1b is further screwed into the coupler 4. After that, similarly, the other steel bar 1b is connected to the other steel bar 1a by using the other coupler 4. With such a configuration, the pair of steel bars 1 and 1a to be connected are previously fixed, and each steel bar 1, 1a is fixed.
Even when the male screw 2 of a has a phase difference, the gap g of the two couplers 4 can absorb the phase difference and be connected.

FIG. 2 shows the relationship between the phase difference between the male screws 2 of the steel bars 1 and 1a and the gap g (see FIG. 3). FIG. 2A shows the case where the phase difference between the male screws 2 of the pair of steel bars 1 and 1a is 0, and the coupler 4 has a degree of freedom in the length of the gap g. FIG. 2B shows the case where the phase difference is ½ rotation, which is the maximum, and the gap g absorbs the phase difference of the screw by ¼ rotation. By connecting this at two points, the maximum phase difference 1/2 rotation of the screws at both ends can be absorbed.

FIG. 1 shows two examples of connection methods for the threaded joint of the present invention. In the example shown in FIG. 1 (a), the steel bars 1 and 1a to be connected are preliminarily screwed with the couplers 4, respectively. By rotating these couplers 4 at the time of connection, one steel bar 1 and the auxiliary steel bar 1b are screwed. Then, similarly, the auxiliary steel bar 1b and the other steel bar 1a are screwed together to form the auxiliary steel bar 1b.
This is a case where the steel bars 1 and 1a are connected to each other by interposing.

In the example shown in FIG. 2 (b), two couplers are screwed into the auxiliary steel bar 1b in advance, and one of the steel bars 1 and the auxiliary steel bar 1b is screwed by rotating these couplers 4 at the time of connection. Similarly, the auxiliary steel bar 1b and the other steel bar 1a are screwed together,
This is a case where the steel bars 1 and 1a are connected to each other with the auxiliary steel bar 1b interposed. The connection method is not limited to these.

FIG. 4 shows an embodiment of a threaded joint for a steel bar according to the present invention. FIG. 4 (a) shows a connecting portion between one steel bar 1 to be connected and an auxiliary steel bar 1b. Coupler 4
A female screw 3 is formed on the inner peripheral portion of the male screw 2 of the steel rod 1 and the auxiliary steel rod 1b to be connected.

In this example, after the steel bar 1 and the auxiliary steel bar 1b and the coupler 4 are screwed together, the grout material 6 is filled from the grout injection hole 7 provided in the coupler 4 to improve the joint rigidity.

FIG. 4 (c) shows a modified example of the coupler 4. The outer diameter of the coupler 4 is not limited to the regular hexagon as shown in FIG. 4 (b), but a circular shape as shown in FIG. 4 (c) or the like. But it's okay.

FIG. 5 shows a connecting portion between one of the steel bars 1 and the auxiliary steel bar 1b to be connected in another embodiment of the present invention. In this example, in order to fix the coupler 4 to the steel bar 1 and the auxiliary steel bar 1b, nuts 5 screwed with these are attached to both ends of the coupler 4 and tightened by the nut 5.

FIG. 6 shows a connecting portion of the other steel bar 1a to be connected to the auxiliary steel bar 1b according to still another embodiment of the present invention. When connecting steel bars 1 and 1a having different outer diameters or auxiliary steel bars 1b to each other,
1a and a coupler 4 having a female screw 3 having different left and right screw shapes so as to be screwed into the male screw 2 of the auxiliary steel bar 1b
By using steel bars 1 and 1a or auxiliary steel bars 1
b It is possible to cope with the difference in outer diameter between the two.

[0034]

[Effects of the Invention] In the threaded joint of the steel bar, the gap is set to ¼ or more of the thread pitch, so that even if the two steel bars to be connected have a phase difference, the third steel bar The gap between the two couplers due to the interposition of the auxiliary steel bars absorbs the phase difference, and the steel bars can be connected to each other.

Further, the gap can be halved as compared with the case where one coupler that directly connects two steel bars to be connected absorbs the gap. Therefore, the backlash is small and high rigidity can be secured. Further, even when the two steel bars to be connected have a misalignment, the absorption range of the misalignment is large.

The coupler does not have a complicated structure and is excellent in workability and economy.

The steel bar and the coupler can be fixed by tightening the fixing nuts from both ends of the coupler.

If the grout material is filled after the coupler and the steel bar are screwed together, higher joint rigidity can be obtained.

[Brief description of drawings]

1A and 1B are schematic views showing a connection method in a threaded joint of the present invention.

2 (a) and 2 (b) are cross-sectional views showing a screwed state of a threaded portion for explaining the action of the threaded joint for a steel bar of the present invention.

FIG. 3 is an explanatory diagram showing a relationship between a screw pitch and a gap.

FIG. 4 is a view showing a connecting portion between one steel bar and an auxiliary steel bar to be connected in one embodiment of the present invention, (a) is a sectional view, (b) is a side view of a coupler, and (c) is a coupler. It is a side view which shows the modification of.

FIG. 5 is a cross-sectional view showing a connecting portion between one steel bar and an auxiliary steel bar to be connected in another embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a connecting portion of another steel bar to be connected to an auxiliary steel bar in still another embodiment of the present invention.

FIG. 7 is a sectional view showing a conventional example.

FIG. 8 is a sectional view showing another conventional example.

FIG. 9 is a sectional view showing still another conventional example.

FIG. 10 is a sectional view showing still another conventional example.

[Explanation of symbols]

p ... screw pitch, g ... gap length (gap), 1, 1
a ... steel bar, 1b ... auxiliary steel bar, 2 ... male screw, 3 ... female screw,
4 ... Coupler, 5 ... Nut, 6 ... Grout material, 7 ... Grout injection hole, 8 ... Precast member, 9 ... Sleeve, 1
0 ... screw

Claims (4)

[Claims] 1. A male screw is provided at a connection end of a pair of steel bars to be connected, and an auxiliary steel bar provided with a male screw is arranged between the pair of steel bars. It is connected by two couplers each having an internal thread to be engaged with an external thread of each steel bar and an auxiliary steel bar, and an axial gap generated between the internal thread of each said coupler and the external thread of each steel bar and an auxiliary steel bar is defined by a screw pitch. A steel bar threaded joint characterized by being set to 1/4 or more. 2. The thread pitch of any or all of the respective couplers and the respective steel bars and auxiliary steel bars is different, and occurs between the female thread of each coupler and the male thread of each of the steel bars and auxiliary steel bars. The steel bar threaded joint according to claim 1, wherein the gap is ¼ or more of any minimum thread pitch. 3. The threaded joint for a steel bar according to claim 1, wherein a gap formed between each coupler and each of the steel bars and the auxiliary steel bars is filled with a grout material. 4. The threaded joint for a steel bar according to claim 1, 2 or 3, wherein both ends of each coupler are fixed by nuts that are screwed with male threads of the respective steel bars and auxiliary steel bars.