Reinforcement bar joints

Abstract

Connecting two reinforcing bars. [Solution] The rebar joint (10) comprises a joint body (20) that connects to a first rebar (50), and an attachment cylinder (30) that connects its cylindrical outer surface to the joint body and its cylindrical inner surface to a second rebar (60). The joint body comprises a pressure contact surface (22) to which the first rebar is friction-welded, and an insertion hole (21) for inserting the end of the second rebar together with the attachment cylinder. A tapered female thread (25) is formed on the inner surface of the insertion hole as a multi-start thread, with the diameter decreasing towards the back of the insertion hole. A tapered male thread (34) is formed on the outer surface of the attachment cylinder as a multi-start thread that fits into the tapered female thread, and a female thread (33) is formed on the inner surface of the attachment cylinder that fits into the male thread (61) formed on the outer surface of the end of the second rebar. The lead (34L) of the tapered male thread is the same as the lead (33L) of the female thread.

Description

Technical Field

[0001] The present invention relates to a joint for reinforcing bars for connecting two reinforcing bars.

Background Art

[0002] As an example of a joint for reinforcing bars for connecting two reinforcing bars, a lock nut and a coupler are sequentially fitted onto each of the two reinforcing bars having a male thread formed on the outer peripheral surface, and a pair of couplers fitted onto the reinforcing bars are each rotated so as to move away from the lock nut, and the ends of the pair of couplers are fitted together with screws, and finally the lock nut is rotated so as to approach the coupler, and the pair of couplers are sandwiched by the pair of lock nuts (see Patent Document 1 (FIG. 9)). In addition, there are various other types of joints for reinforcing bars (Patent Documents 2 and 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to connect two reinforcing bars with a configuration different from the above-described configuration.

Means for Solving the Problems

[0005] The rebar joint of the present invention comprises a joint body for connecting to a first rebar, and a cylindrical accessory tube which connects its outer surface to the joint body and its inner surface to a second rebar. The joint body comprises a pressure contact surface formed on its outer surface to which the first rebar is friction-pressed, and an insertion hole for inserting the end of the second rebar together with the accessory tube, the inner surface of which a tapered female thread is formed as a multi-start thread whose diameter decreases towards the back of the insertion hole. The accessory tube comprises a tapered male thread formed on its outer surface which fits into the tapered female thread as a multi-start thread, and a female thread formed on its inner surface which fits into the male thread formed on the outer surface of the end of the second rebar. The lead of the tapered male thread is the same as the lead of the female thread. [Effects of the Invention]

[0006] According to the rebar joint of the present invention, the first rebar and the joint body can be connected by friction welding, and the attached cylinder can be connected to the joint body and the second rebar by rotating the attached cylinder, thereby enabling the connection of the first and second rebars. Furthermore, while the connection between the attached cylinder and the joint body is made easier by using a multi-start screw, the lead of the tapered male thread and the lead of the female thread are made the same, so the attached cylinder can be rotated while fitted to both the joint body and the second rebar. [Brief explanation of the drawing]

[0007] [Figure 1] An explanatory diagram showing a reinforcing bar joint according to the first embodiment of the present invention. [Figure 2] Figures (A) and (B) show a cross-sectional view and a side view of the joint body used in the reinforcing bar joint of the first embodiment. [Figure 3] Figures (A) to (C) show a front view, cross-sectional view, and side view of the accessory cylinder used in the reinforcing bar joint of the first embodiment. [Figure 4] Figures (A) to (H) are explanatory diagrams showing how to use reinforcing bar connectors. [Modes for carrying out the invention]

[0008] As shown in Figure 1, the reinforcing bar joint 10 of the first embodiment of the present invention comprises a joint body 20 and an attached cylinder 30 connected inside the joint body 20. The reinforcing bar joint 10 connects a first reinforcing bar 50 and a second reinforcing bar 60 such that their respective axes 50a and 60a are aligned in a straight line.

[0009] In this embodiment, the first reinforcing bar 50 and the second reinforcing bar 60 are both threaded reinforcing bars, a type of deformed steel bar, and are identical. The first reinforcing bar 50 and the second reinforcing bar 60 extend in a straight line, and male threads 51 and 61, respectively, are formed on their outer surfaces as parallel threads. However, the first reinforcing bar 50 does not have to be the same as the second reinforcing bar 60.

[0010] As shown in Figures 1 and 2, the joint body 20 includes an insertion hole 21 into which the end of the second reinforcing bar 60 is inserted together with the attached cylinder 30, and a pressure contact surface 22 that is friction-pressed against the first reinforcing bar 50. More specifically, the joint body 20 includes a cylindrical body section 23 and a bottom plate section 24 that closes one end of the body section 23 in the penetrating direction. The outer circumferential surface of the body section 23 is a cylindrical surface. The other end of the body section 23 in the penetrating direction is an open end. The inside of the body section 23 is the insertion hole 21. The insertion hole 21 is tapered, with its diameter decreasing from the open end towards the back of the hole. A tapered female thread 25 is formed on the inner circumferential surface of the body section 23 (insertion hole 21) as a tapered screw. The joint body 20 is formed with an injection port 26 for injecting grout material that leads to the back of the insertion hole 21 (bottom plate section 24). More specifically, the injection port 26 is formed near the bottom plate portion 24 of the main cylindrical portion 23, penetrating the cylindrical portion 23 in the thickness direction. The outer surface of the joint body 20 is formed by the outer circumferential surface of the main cylindrical portion 23 and the outer surface of the bottom plate portion 24. The outer circumferential surface of the main cylindrical portion 23 is a cylindrical surface. The outer surface of the bottom plate portion 24 is circular and is a plane perpendicular to the axis 20a of the joint body 20 (tapered female thread 25). The outer surface of the bottom plate portion 24 becomes the pressure welding surface 22 for friction welding the first reinforcing bar 50.

[0011] As shown in Figures 1 and 3, the attached cylinder 30 has a cylindrical central cylinder portion 31. A through hole 32 is formed inside the central cylinder portion 31 for the second reinforcing bar 60 to pass through. The through hole 32 extends in a straight line. A female thread 33, which is a parallel thread, is formed on the inner circumferential surface of the central cylinder portion 31 (through hole 32). The female thread 33 fits into the male thread 61 of the second reinforcing bar 60. On the outer circumferential surface of the central cylinder portion 31, one end in the direction of penetration has a diameter that increases from that end to the other end. A tapered male thread 34, which is a tapered thread, is formed on the outer circumferential surface of the central cylinder portion 31 at one end in the direction of penetration. The tapered male thread 34 fits into the tapered female thread 25. The axis 30a of the attached cylinder 30 is also the center line (axis) of the female thread 33 and the tapered male thread 34. The precision with which the tapered male thread 34 and the tapered female thread 25 fit together is higher than the precision with which the male thread 61 and the female thread 33 fit together. A nut portion 35 is formed at the other end of the central cylindrical portion 31. The outer circumferential surface of the nut portion 35 is the tool mounting surface and is hexagonal when viewed from the through direction. The nut portion 35 and the tapered male thread 34 are separated in the through direction. Between the nut portion 35 and the tapered male thread 34, a flange portion 36 is formed on the outer circumferential surface of the central cylindrical portion 31, projecting radially outward. The flange portion 36 is circular when viewed from the through direction. When the accessory cylinder 30 is fitted into the joint body 20, the flange portion 36 collides with the end face of the main cylindrical portion 23 of the joint body 20 to position it. As described above, the accessory cylinder 30 comprises a central cylindrical portion 31, a tapered male thread 34, a flange portion 36, a nut portion 35, and a female thread 33.

[0012] The female thread 33 and the male thread 61 are single-start threads. Therefore, for the female thread 33, the lead 33L and the pitch 33P are the same dimension. Similarly, for the male thread 61, the lead 61L and the pitch 61P are the same dimension. The tapered male thread 34 and the tapered female thread 25 are multi-start threads, and in this embodiment, they are double-start threads. Therefore, for the tapered male thread 34, the lead 34L is twice the pitch 34P. Similarly, for the tapered female thread 25, the lead 25L is twice the pitch 25P. Note that in the diagram, double-start threads are made easier to understand by placing dots only on the top of one thread (start) to make it easier to understand that it is different from the other thread (start). The lead 34L of the tapered male thread 34 and the lead 33L of the female thread 33 are the same dimension. In other words, the pitch 34P of the tapered male thread 34 is half the pitch 33P of the female thread 33. As a result, when the attached cylinder 30 fitted onto the second reinforcing bar 60 is rotated to fit onto the joint body 20, the amount of movement of the female thread 33 relative to the male thread 61 is equal to the amount of movement of the tapered male thread 34 relative to the tapered female thread 25, in terms of axial movement.

[0013] The method for using the rebar joint 10 of this embodiment is as follows: (1) to (4). (1) As shown in Figures 4(A) and 4(B), the end face of the first reinforcing bar 50 is friction-welded to the outer surface (pressure welding surface 22) of the bottom plate portion 24 of the joint body 20. When friction-welding, the axis 50a of the first reinforcing bar 50 is aligned with the axis 20a of the joint body 20 (center of the bottom plate portion 24). As a result of friction-welding, the first reinforcing bar 50 and the joint body 20 become an inseparable unit, forming a reinforcing bar with a joint body. (2) As shown in Figures 4(C) and 4(D), the end face of the second reinforcing bar 60 is aligned with the through hole 32 of the attachment cylinder 30, and the attachment cylinder 30 is rotated to fit the female thread 33 of the attachment cylinder 30 onto the male thread 61 of the second reinforcing bar 60, so that one end of the second reinforcing bar 60 protrudes sufficiently from the attachment cylinder 30. As a result, the axis 30a of the attachment cylinder 30 and the axis 60a of the second reinforcing bar 60 are approximately aligned. When rotating, a tool is used on the nut portion 35 as needed. (3) As shown in Fig. 4(E), insert one end of the second reinforcing bar 60 (the end protruding from the attached cylinder 30) into the insertion hole 21 of the joint body 20, and turn the attached cylinder 30 so as to insert it into the insertion hole 21. Then, the male screw 33 of the attached cylinder 30 rotates while fitting into the female screw 61 of the second reinforcing bar 60, and the tapered male screw 34 of the attached cylinder 30 rotates while fitting into the tapered female screw 25 of the joint body 20. When the attached cylinder 30 is continuously rotated, as shown in Fig. 4(F), the flange portion 36 of the attached cylinder 30 collides with the end face of the main body cylinder portion 23 of the joint body 20. (4) As shown in Figs. 4(G)(H), when grout material 81 is injected from the injection port 26 of the joint body 20, the gap formed between the joint body 20, the attached cylinder 30, and the second reinforcing bar 60 is filled with the grout material 81. By the grout material 81 solidifying, the first reinforcing bar 50 and the second reinforcing bar 60 are firmly connected via the reinforcing bar joint 10.

[0014] As described above, for the reinforcing bar joint 10 of the present embodiment, friction pressure welding is used for connecting the first reinforcing bar 50 and the joint body 20, rotation of the attached cylinder 30 is used for connecting the second reinforcing bar 60 and the attached cylinder 30, and rotation of the attached cylinder 30 is used for connecting the joint body 20 and the attached cylinder 30, so that the first reinforcing bar 50 and the second reinforcing bar 60 can be easily connected with their axes 50a, 60a aligned with each other. Also, since multi-threaded screws are used for the tapered male screw 34 and the tapered female screw 25, compared with single-threaded screws, the connection (fitting) between the joint body 20 and the attached cylinder 30 becomes easier. Also, since the lead 34L of the tapered male screw 34 and the lead 33L of the male screw 33 are made the same size, the operation of turning the attached cylinder 30 can be performed in a state where it is fitted to both the joint body 20 and the second reinforcing bar 60.

[0015] The present invention is not limited to this embodiment, and can be appropriately changed within the scope not departing from the gist thereof.

Explanation of Reference Numerals

[0016] 10 Reinforcing bar joint 20 Joint body 20a Axis 21 Insertion hole 22 Crimping surface 23 Body cylinder part 24 Bottom plate part 25 Tapered thread 25L Lead 25P Pitch 26 Injection port 30 Attachment cylinder 30a Axis 31 Central cylinder part 32 Through hole 33 Thread 33L Lead 33P Pitch 34 Tapered male thread 34L Lead 34P Pitch 35 Nut part 36 Flange part 50 First reinforcing bar 50a Axis 51 Male thread 60 Second reinforcing bar 60a Axis 61 Male thread 61L Lead 61P Pitch 81 Grout material

Claims

[Claim 1] The device comprises a joint body that connects to a first reinforcing bar, and a cylindrical accessory tube that connects its outer surface to the joint body and its inner surface to a second reinforcing bar. The joint body comprises a pressure contact surface formed on its outer surface to which the first reinforcing bar is friction-pressed, and an insertion hole for inserting the end of the second reinforcing bar together with the attached cylinder, the inner surface of which has a tapered female thread formed as a multi-start thread, with the diameter decreasing towards the back of the insertion hole. The attached cylinder has a tapered male thread formed on its outer circumference, which is a multi-start thread that fits into the tapered female thread, and a female thread formed on its inner circumference, which fits into the male thread formed on the outer circumference of the end of the second reinforcing bar. A rebar connector characterized in that the lead of the tapered male thread is the same as the lead of the female thread.

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