Reinforcement butt-joining structure and compression device for reinforcement connecting sleeve

Abstract

To provide a compression device capable of obtaining a large push-in amount of a steel pipe sleeve by relatively small compression force, and a joint structure of a reinforcement obtained by the compression device.SOLUTION: A compression device for the steel pipe sleeve for connecting reinforcing steel comprises dies 2 and 3 for reducing the diameter of a steel pipe sleeve 1 and crimping it to a reinforcing steel 10, and driving means for the dies 2 and 3. The dies 2 and 3 are provided with convex strips 21 and 31 for forming a valley part 12 by locally compressing and reducing the diameter of the steel pipe sleeve 1 from six sides, and groove parts 22 and 32 for forming a ridge part 11 formed by thickening a steel pipe material on both sides in the circumferential direction when the valley part 12 is formed.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a butt joint structure for reinforcing bars and a compression device for reinforcing bar connection sleeves to obtain this joint structure. [Background technology]

[0002] A conventional method for butt-jointing deformed reinforcing bars used at construction sites involves crimping a steel pipe sleeve onto the tip of a pair of deformed reinforcing bars to butt-join them (see, for example, Patent Document 1). In this method, the deformed reinforcing bars are inserted into a cylindrical steel pipe sleeve from both ends and butt-joined, and the sleeve is cold compressed, joining the two reinforcing bars through its deformation. This joint structure transmits axial stress to the reinforcing bars by utilizing the mechanical frictional force caused by the engagement between the knots of the deformed reinforcing bars and the inner circumference of the sleeve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-256767 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional butt joint method for deformed rebars, the inner diameter of the steel pipe is set larger than the outer diameter of the rebar for ease of construction. Therefore, the steel pipe must be pushed in far enough to fill the gap between the two and ensure that the inner circumference of the steel pipe sleeve is tightly attached to the bottom of the rebar joint. A larger pushing depth increases the compression ratio and the required surface pressure, resulting in a correspondingly large surface pressure being applied to the die. To ensure the required surface pressure without increasing the size of the hydraulic compressor, the die width (i.e., the compressed length of the sleeve) must be relatively small. This increases the number of compressions required to compress the required length, resulting in poor construction. Furthermore, a higher compression ratio reduces the cross-sectional area of ​​the crimped steel pipe sleeve, making it difficult to ensure the required tensile strength. Therefore, the objective of the present invention is to provide a compression device that can compress a steel pipe sleeve with a relatively small surface pressure despite a large pushing amount of the steel pipe sleeve, and that can give the steel pipe sleeve sufficient tensile strength after compression, and a reinforcing bar joint structure obtained thereby. [Means for solving the problem]

[0005] In the following description, reference will be made to the reference numerals in the accompanying drawings, but the present invention is not limited thereto. In order to solve the above problems, in the joining structure of reinforcing bars 10, 10 of the present invention, reinforcing bars 10, 10 are butt-joined and inserted into a steel pipe sleeve 1 from both ends and joined together within the crimped steel pipe sleeve 1. The crimped steel pipe sleeve 1 has thick-walled ridge portions 11 and thin-walled valley portions 12, each having a predetermined length in the axial direction, spaced at predetermined angular intervals in the circumferential direction, and the ridge portions 11 and valley portions 12 are connected to each other on the outer periphery with curved surfaces, and the inner periphery is in close contact with the outer periphery of the reinforcing bar 10, giving it a structure with a roughly polygonal cross section. To solve the above problems, the compression device for a steel pipe sleeve 1 for connecting reinforcing bars of the present invention comprises dies 2, 3 that reduce the diameter of the steel pipe sleeve 1 to crimp it onto a reinforcing bar 10, and a drive means for the dies 2, 3. The dies 2, 3 comprise convex ridges 21, 31 that locally compress and reduce the diameter of the steel pipe sleeve 1 from all sides to form valleys 12, and grooves 22, 32 that form ridges 11 formed by increasing the thickness of the steel pipe material on both circumferential sides when the valleys 12 are formed. [Effects of the Invention]

[0006] According to the reinforcing bar joint structure of the present invention, the reinforcing bars have sufficient connection strength, can be easily installed, and can also contribute to energy savings in installation. According to the compression device for steel pipe sleeves for connecting reinforcing bars of the present invention, the above-mentioned excellent reinforcing bar joint structure can be easily obtained even though it is relatively small in size. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view showing a reinforcing bar connection structure according to the present invention; [Figure 2] FIG. 2 is a cross-sectional view of the connection of the reinforcing bar in FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 4] 1 is a perspective view of a die in a compression device for a steel pipe sleeve for connecting reinforcing bars according to the present invention. FIG. [Figure 5] FIG. 5 is a side view of the die of FIG. 4. [Figure 6] 6 is a cross-sectional view taken along the line VI-VI in FIG. 5. [Figure 7] 7 is a cross-sectional view taken along the line VII-VII in FIG. 6. [Figure 8] FIG. 10 is a cross-sectional view of a reinforcing bar connection according to another embodiment. [Figure 9] FIG. 10 is a cross-sectional view of a die according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the present invention will be described with reference to the drawings. 1 to 3 show a reinforcing bar joint structure according to the present invention. In this reinforcing bar joint structure, reinforcing bars 10 are inserted into a steel pipe sleeve 1 with both ends butt-joined and joined together within the crimped steel pipe sleeve 1. The crimped steel pipe sleeve 1 has thick-walled ridge portions 11 and thin-walled valley portions 12, each having a predetermined length in the axial direction, alternately arranged at 60° intervals in the circumferential direction. The outer peripheries of the ridge portions 11 and valley portions 12 are continuous with each other through curved surfaces, and as shown in FIG. 3, have a cross-sectional shape that roughly resembles a six-pointed star. The inner periphery of the steel pipe sleeve 1 is in close contact with the outer periphery of the reinforcing bar 10, down to the bottom of the joints 10a.

[0009] The joining of the reinforcing bars is carried out by inserting the reinforcing bars 10, 10 into the steel pipe sleeve 1 from both ends, butting them together, placing them between the dies 2, 3 shown in Figures 4 to 6, and compressing the dies 2, 3 using a driving means not shown.

[0010] The dies 2, 3 are provided with convex rib portions 21, 31 that locally compress the steel pipe sleeve 1 from all six directions to reduce its diameter, thereby forming a valley portion 12, and groove portions 22, 32 that form a thick-walled ridge portion 11 by allowing the steel pipe material to escape to both sides in the circumferential direction when forming the valley portion 12.

[0011] The amount of pressing required to join the reinforcing bar 10 to the steel pipe sleeve 1 can be ensured with a relatively small surface pressure due to localized compression by the ridges 21, 31. While the ridges 21, 31 press the outer periphery of the steel pipe sleeve 1, a portion of the steel pipe material is allowed to escape to the grooves 22, 23, thereby reducing the overall surface pressure required for compression. Therefore, a die with a larger compression width can be formed with the same surface pressure.

[0012] At the joint between the reinforcing bars 10, 10 joined by compressing the steel pipe sleeve 1 with the dies 2, 3, six thick ridges 11 are formed in the axial direction to function as ribs, improving the tensile strength.

[0013] Figure 8 shows a reinforcing bar joint structure according to another embodiment of the present invention. In this reinforcing bar joint structure, the crimped steel pipe sleeve 1 has thick-walled ridge portions 11a, 11b and thin-walled valley portions 12a, 12b, each having a predetermined length in the axial direction, alternately arranged at 60° intervals in the circumferential direction. However, only the outer peripheries of the four ridge portions 11a located at two diagonal corners and the adjacent valley portions 12a are continuous with each other through curved surfaces. The other two ridge portions 11b are formed between two flat surfaces that are joined at 120°. As in the previous embodiment, the inner periphery of the steel pipe sleeve 1 is in intimate contact with the outer periphery of the reinforcing bar 10, down to the bottom of the joints 10a.

[0014] As shown in Figure 9, the dies 2, 3 used to obtain the above-mentioned joining structure are equipped with two convex portions 21, 31 which form the valley portion 12a of the steel pipe sleeve 1 of Figure 8, four groove portions 32, 32 which form the thick-walled ridge portion 11a by allowing the steel pipe material to escape to both sides in the circumferential direction when forming the valley portion 12a, and two flat portions 23, 33 which join at 120° to each other on both sides of the joining side of each die 2, 3 so as to form the other two ridge portions 11b of the steel pipe sleeve 1.

[0015] The above embodiment shows only one example, and can be modified as appropriate within the scope of the present invention. For example, in the above embodiment, the crimped steel pipe sleeve 1 has ridges 11 and valleys 12 at 60° intervals in the circumferential direction, but they can also be arranged at other angles. Furthermore, in the above embodiment, the crimped steel pipe sleeve 1 has a structure that roughly has a six-pointed star shape in cross section, but the number of ridges 11 and valleys 12 that the crimped steel pipe sleeve 1 has is not limited to six. [Explanation of symbols]

[0016] 1 Steel pipe sleeve 10 Reinforced concrete 10a Fushi 11 Mausoleum 11a Mausoleum 11b Mausoleum 12 Valley 12a Tanibe 12b Tanibe 2 dice 21 Convex portion 22 Groove 23 Plane part 3 dice 31 Convex portion 32 Groove 33 Plane part

Claims

1. The reinforcing bars inserted into the steel pipe sleeve from both ends are joined together within the crimped steel pipe sleeve, The crimped steel pipe sleeve has thick ridge portions and thin valley portions which are spaced at predetermined angles in the circumferential direction and have predetermined lengths in the axial direction, and the ridge portions and valley portions are continuous with each other on the outer periphery with curved surfaces, and the inner periphery is in close contact with the outer periphery of the reinforcing bar, resulting in a roughly polygonal cross section.

2. The reinforcing bars inserted into the steel pipe sleeve from both ends are joined together within the crimped steel pipe sleeve, The crimped steel pipe sleeve has thick ridge portions and thin valley portions each having a predetermined length in the axial direction at a predetermined angle in the circumferential direction, and the outer peripheries of the four ridge portions located at two diagonal corners and the valley portions adjacent to them are continuous with each other with curved surfaces, and the inner periphery is in close contact with the outer periphery of the reinforcing bar, resulting in a roughly polygonal cross-section.

3. A compression device for the steel pipe sleeve to obtain the butt joint structure of the reinforcing bar according to claim 1 or 2, The method includes a die that reduces the diameter of the steel pipe sleeve and crimps it onto the reinforcing bar, and a drive means for the die. The die is characterized by having a convex portion that locally compresses and reduces the diameter of the steel pipe sleeve from six sides to form the valley portion, and a groove portion that forms the ridge portion by increasing the thickness of the steel pipe material on both circumferential sides when the valley portion is formed.

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