JPS6315454Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a threaded steel bar manufactured by hot rolling used for concrete reinforcement and whose base section has a regular hexagonal, regular octagonal, regular decagonal, or regular dodecagonal shape. Pertains to.

Steel rods for concrete reinforcement conventionally used in civil engineering and construction work include deformed steel rods without threaded ends and deformed steel rods with threaded ends. Some threaded steel bars have a circular or elliptical cross-sectional shape at the base, and protrusions (hooks) are distributed in a screw-like manner on the surface of the base in a direction transverse to the axis of the steel rod. The projections (ribs) provided continuously in the axial direction may or may not be provided, and even if the ribs are provided, the female threads will not Two types have been put into practical use: one that protrudes continuously and low enough not to impede progress. Functionalities required when using these deformed steel bars in civil engineering and construction work include the strength limit as a steel bar, adhesion with concrete, and connectivity as a construction material. However, the above-mentioned functionality of the above-mentioned deformed steel bars currently in practical use has the following problems. The welding method, gas pressure welding method, screw joint method, crimp joint method, etc. are widely known as methods for connecting steel bars for general irregular shaped rods, but all of them require specialized equipment or special tools. ,
There are also limitations in handling technology.

As a solution to these problems, the above-mentioned threaded steel rod, which is a method of simple screw connection using a coupler joint, has been developed and put into practical use, but it still has the following problems.

(1) Conventional threaded steel rods have dispersed protrusions that function as threaded threads, and the shape of the threads and ribs, as well as the horizontal edges of the steel bar, can be distributed as conditions for entering the female thread. As a result, the surface area occupied by the edges and ribs must become smaller, resulting in poor concrete adhesion. (2) Conventional threaded steel bars have a true circular or deformed elliptical cross-sectional shape, so spanners cannot be used for connection work, and pipe wrenches or special mechanical tightening tools are required. , and lacks generality. Furthermore, when using a pipe wrench, there are drawbacks such as damage to the threads.

The present invention is intended to solve these drawbacks of the conventional art, and its structure, function and effects will be explained with reference to the drawings.

Fig. 1 shows a threaded steel bar based on a regular hexagon according to the present invention, 1 indicates the base portion of the steel bar, its cross-sectional shape is a regular hexagon, and each of the six vertices has a radius R. ₁ is drawn, and when the radius of the circumscribed circle of a regular hexagon is r ₁ , it is assumed that 0mm≦R ₁ ≦r ₁ /6. In addition, the shaded edge part A in FIG. 1b has a larger surface area than a perfect circle or an ellipse, and is superior in terms of adhesion to concrete.

Figure 2 shows a threaded steel rod with a regular octagon as its base. When the circumscribed circle radius of the regular octagon is r ₂ , the radius R ₂ of each of the eight vertices satisfies 0mm≦R ₂ ≦0.128r ₂ . The shaded area A is similar to the regular hexagonal shape shown in FIG. 1, and has better concrete adhesion than the conventional threaded steel rod.

Next, as shown in Fig. 1 and Fig. 2, the threaded steel rod according to the present invention has a cross section of a regular hexagon or a regular octagon, and the outer periphery of the base portion of the steel rod has two opposing parallel faces of the polygon. A thread-like protrusion (screw holder) 2 is provided except for 3 and 3', and the cross-sectional shape of the screw holder 2, that is, the hatched part B in FIG. _. This is a threaded steel rod for reinforcing concrete that has a regular polygonal base portion and is characterized by extending all the way and being screwed into a female thread. The surfaces of the base portion facing the center of the steel rod base portion, that is, the opposing surfaces in Figure b, are parallel planes, and a spanner can be applied to the two sides 3 and 3' without edges, so the two steel rods This makes it easier to screw and tighten the coupler joint into the coupler joint. In addition, according to the present invention, the height of the screw bracket on each side of the regular polygon is formed into an almost occluded circle, which increases the outer circumferential area of the base, which strengthens adhesion to concrete and has the effect of preventing twisting and rotation. be. Furthermore, regarding the bendability of the steel bar, compared to a threaded steel bar whose basic cross section is not a perfect circle and an oval shape, the regular polygonal steel bar according to the present invention has almost the same bending force on average in any direction, and is easy to use in the field. bending work is also easier. In this invention, the cross section of the steel bar is limited to an even polygon of 6 to 12 because a polygon of 6 or less causes the problem of directionality during bending of the steel bar, and a polygon of 12 or more makes it difficult to apply a wrench. Therefore, in practice, a regular octagon is most desirable.

As explained above, the threaded steel rod according to the present invention can be operated with a spanner, has excellent adhesion to concrete, bending of the steel rod, prevents twisting and rotation, and has the advantage of simplifying handling technology on site. .

[Brief explanation of the drawing]

Figures 1 and 2 both show threaded steel rods based on regular hexagons and regular octagons, showing examples of the present invention. Figure a is a side view, Figure b is a cross-sectional structure,
The figure shows an explanatory diagram of the present invention. In the figure, 1: steel bar base, 2: screw bracket,
3, 3': Opposing parallel planes without screw edges.

Claims (1)

[Scope of utility model registration request] A thread-like protrusion (screw holder) is provided on the outer periphery of the base portion of a steel rod having a cross section of a regular hexagon to a regular dodecagon and an even polygon, except for one parallel two opposing faces of the even polygon, and The cross-sectional shape of the screw holder is formed into a substantially occluded circle on each side of the base portion of the steel rod, and the outer periphery of the screw holder is located at approximately the same distance from the center of the steel rod and extends in the axial direction, A threaded steel rod for reinforcing concrete that has a regular polygonal base and is characterized by being screwed into a female screw.