Coupler for deformed rebar using threaded rebar

Abstract

To provide a coupler for a deformed reinforcement using a screw node reinforcement which dispenses with the management of a filling state, the management of injection viscosity, the management of industrial wastes remaining after construction, etc., without filling grout between tooth surfaces.SOLUTION: A coupler 10 is provided with a main cylinder 11 to which the end part of one reinforcement 4L is friction-welded and a sub-cylinder 12 screwed to the anti-friction-welded side of the bag hole 5H bored along the axis of the main cylinder 11. A bag hole female screw 5F to which a screw node 4T of the other reinforcement 4R is screwed is formed on the friction pressure contact side of the bag hole 5H, and an enlarged diameter female screw 9F formed larger in diameter than the bag hole female screw 5F and having a different pitch is provided on the anti-friction pressure contact side of the bag hole 5H. The sub-cylinder 12 is provided with a sleeve part 8 having a sleeve part male screw 8M screwed to the enlarged diameter female screw 9F, and a nut part 13 coaxial with the sleeve part 8 and integrally formed at the end of the sleeve part 8.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a coupler for deformed reinforcing bars that uses threaded reinforcing bars, and more particularly to a fastening coupler in which the ends of one opposing reinforcing bar are friction-welded and the other reinforcing bar is inserted into the coupler, preventing loosening between the reinforcing bar and the coupler and forming an extended reinforcing bar that transmits axial force. [Background technology]

[0002] When constructing buildings and civil engineering structures using reinforced concrete, the deformed steel bars (threaded steel bars, bamboo-shaped steel bars, etc.) used as concrete reinforcement are manufactured to standard lengths, such as 12 meters, to facilitate easy transportation from the factory to the construction site.

[0003] However, when used, they are often extended at the construction site to accommodate the size of the building to which they are being applied and the length of the area to which they are being applied. Both threaded and bamboo-knotted rebars are gradually deformed and shaped by the caliber formed on the roll surface during the rolling process, but the rolls gradually become rough and wear out. Although the roughness can be removed by surface grinding and continued use is possible, a decrease in the diameter of the rolling roll is unavoidable, and the knot pitch varies slightly depending on the manufacturing period. The tooth profile formed in the coupler's connecting hole is made to match the thread pitch of the standard dimensions of the rebar, but with a slightly wider pitch to take into account the rebar's forming tolerances. Therefore, although the coupler can accommodate the difference in thread pitch between the coupler and the rebar and engage, it is unavoidable that some gaps will remain when they engage.

[0004] The gaps between the tooth surfaces are filled with grout (e.g., mortar) to prevent rattle, or a machine screw is inserted from the outside of the coupler toward the surface of the rebar to prevent it from coming loose. Examples of the former are proposed in Patent Document 1 (U.S. Patent No. 4,666,326) and Patent Document 2 (JP 2018-178365), while examples of the latter are proposed in Patent Document 3 (U.S. Patent No. 5,046,878) and Patent Document 4 (U.S. Patent No. 7,107,735). In both cases, the goal of achieving a perfect fastening results in the lengthening of the coupler and the increasing fastening load. Therefore, the emergence of a coupler that allows for easy torque management (achieving low torque and uniform fastening force) to prevent rattle and prevent it from coming loose is eagerly awaited.

[0005] Furthermore, there are cases where the thickness of rebar needs to be gradually reduced or increased depending on the application area of ​​the building, or when deformed rebar needs to be changed from threaded joints to bamboo joints. It is also possible to apply it to joints. This is because it is possible to reduce the amount of rebar used and promote the use of stock. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 4,666,326 [Patent Document 2] Patent Publication No. 2018-178365 [Patent Document 3] U.S. Patent No. 5,046,878 [Patent Document 4] U.S. Patent No. 7,107,735 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and its object is to , Ne Taking advantage of the creaking of the mountain The first reinforcing bar and the second reinforcing bar can be firmly fastened in the axial direction. The object of the present invention is to provide a coupler. [Means for solving the problem]

[0008] The coupler for deformed reinforcing bars using threaded reinforcing bars of the present invention is applied to couplers that join the ends of opposing reinforcing bars to form an extended reinforcing bar that transmits axial force, as shown in Figure 1(a). Its features are as follows: The coupler 10 comprises a main cylinder 11 to which the end of one reinforcing bar 4L is friction-welded, and a secondary cylinder 12 that is threadedly fitted into the main cylinder on the side opposite the friction-welded side of a blind hole 5H drilled along the axis of the main cylinder. On the friction welding side of the pocket hole 5H, a pocket hole female thread 5F is formed into which the tip portion of the screw joint 4T of the other reinforcing bar 4R is screwed, and on the anti-friction welding side of this pocket hole, an enlarged diameter female thread 9F is provided which is concentric with the pocket hole female thread 5F but has a larger diameter than the pocket hole female thread 5F, The secondary cylinder 12 is provided with a sleeve portion 8 having a sleeve portion male thread 8M that screws onto this expanding female thread 9F, and a nut portion 13 that is coaxial with the sleeve portion and integrally formed at the end of the sleeve portion, the expanding female thread 9F having a pitch that is different from the pitch of the thread joint 4T of the other rebar 4R, and the nut portion 13 having a nut portion female thread 13F that screws onto the thread joint 4T of the other rebar 4R and has the same pitch and phase as the pocket hole female thread 5F. The sleeve hole 8H of the sleeve portion 8 is formed with a sleeve portion female thread 8F that has the same pitch and phase as the nut portion female thread 13F.

[0009] In another invention, as shown in FIG. 18(b), a coupler 10X comprises a main cylinder 11X to which the end of one reinforcing bar 4L is friction-welded, and a secondary cylinder 12X that is screwed onto the outside of the main cylinder on the side opposite to the friction-welded side. On the friction-welded side of a blind hole 5H drilled along the axis of the main cylinder 11X, there is a blind hole female thread 5F into which the tip of the screw joint 4T of the other reinforcing bar 4R is screwed. On the side opposite to the friction-welded side of the outer circumferential surface of the main cylinder 11X, there is provided an expanding male screw 9M that is concentric with the blind hole female thread 5F but has a larger diameter than the blind hole female thread. The secondary cylinder 12X is provided with a sleeve portion 8X having a sleeve portion female thread 8FX that screws onto the expanding male thread, and a nut portion 13 that is coaxial with the sleeve portion and integrally formed at the end of the sleeve portion, the expanding male thread 9M having a pitch that is different from the pitch of the thread of the other rebar 4R, and the nut portion 13 having a nut portion female thread 13F that screws onto the thread of the other rebar and has the same pitch and phase as the pocket hole female thread 5F. The sleeve hole 8H of the sleeve portion 8X has a sleeve portion female thread 8FX that has the same pitch and phase as the nut portion female thread 13F.

[0010] Although it is not clear, as shown in FIG. 1(a) and FIG. 18(b), the expanding female screw 9F or the expanding male screw 9M has a pitch P4 larger than the pitch P4 of the thread joint 4R of the other reinforcing bar. 9F Or Pitch P 9M is formed.

[0011] Alternatively, the expanding female screw 9F or the expanding male screw 9M has a pitch P smaller than the pitch P4 of the thread joint 4R of the other reinforcing bar. 9F Or Pitch P 9M is formed.

[0012] As shown in Figures 3 and 16, the outer body of the cap screw 5 of the main tube 11 has reaction force relief surfaces 11C and 11E formed on the outer surface of either part in the longitudinal direction of the outer body of the cap screw 5, which serve as reaction force relief surfaces when a desired torque is applied to the nut portion 13.

[0013] As shown in FIG. 9, the main cylinder is formed with a slit 15 extending in the longitudinal direction through which the position of the tip of the inserted reinforcing bar 4R can be seen.

[0014] A slit 16 of approximately the same shape as the slit 15 is formed in the main cylinder 11 at a location opposite the slit 15 .

[0015] As shown in FIG. 13(b), the reinforcing bars to be friction-welded may be deformed reinforcing bars other than threaded reinforcing bars, for example, bamboo-jointed reinforcing bars. [Effects of the Invention]

[0016] According to the present invention, It is possible to provide a coupler that can firmly fasten a first reinforcing bar and a second reinforcing bar together in the axial direction. [Brief explanation of the drawings]

[0020] [Figure 1] This is a vertical cross-sectional view and an overall outline view of the state in which the secondary cylinder is moved to the left in the latter half of the reinforcing bar fastening procedure using a reinforcing bar coupler according to the present invention when P9F=P4+2mm. [Figure 2] 1 is a perspective view of the end of a threaded reinforcing bar to be friction welded before and after pressure welding. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] Arrangement diagram of coupler components in the initial stage of fastening. [Figure 6] A cross-sectional view of a main cylinder with a secondary cylinder attached to it, with rebar screwed into it. [Figure 7] A diagram of measures to prevent rotational misalignment between the main and secondary cylinders before the rebar fastening procedure. [Figure 8] A process diagram of the first half of the reinforcing bar fastening procedure using a reinforcing bar coupler after removing the sleeve body. [Figure 9] FIG. 10 is an overall perspective view of a coupler including a main tube showing the position of the slit. [Figure 10] FIG. 10 is an explanatory diagram showing the position and size of a paint mark. [Figure 11] An external view of the coupler used to check the tip of the rebar. [Figure 12] Cross-sectional view showing the procedure for screwing the secondary barrel onto the main barrel. [Figure 13] Another design using a main cylinder made of rebars of different diameters and types friction-welded together. [Figure 14] Fastening procedure and outline drawing after the procedure is completed (expansion). [Figure 15] Outline drawing of another example after the procedure is completed (expansion). [Figure 16] An external view of a coupler including a main barrel with a polyhedral central barrel. [Figure 17] Right-hand longitudinal section and outline drawing of the secondary cylinder for the latter stage of the rebar fastening procedure. [Figure 18]A diagram of the first half of the rebar fastening procedure using couplers with different secondary tubes. [Figure 19] A longitudinal cross-sectional view and an overall outline view of the state in which the secondary tube is moved to the left in the latter half of the rebar fastening procedure using a coupler with a different secondary tube. [Figure 20] A longitudinal cross-sectional view and an overall outline view of the state in which the secondary tube is moved to the right in the latter half of the rebar fastening procedure using a coupler with a different secondary tube. DETAILED DESCRIPTION OF THE INVENTION

[0021] The coupler for deformed reinforcing bars using threaded reinforcing bars according to the present invention will be described in detail below with reference to drawings showing an embodiment of the coupler. The coupler itself is used to fasten opposing threaded reinforcing bars 4L and 4R according to the location of the building, as shown in Figure 1(a). That is, whether or not grout is used, the coupler aims to firmly join the reinforcing bars by utilizing the creak of the threads, which will be described later. Of course, the coupler is intended to be applied to threaded reinforcing bars, but it is also intended for friction-welded reinforcing bars, so the reinforcing bars to be friction-welded are not limited to threaded reinforcing bars; they can also be bamboo-knot reinforcing bars, which do not exhibit threaded behavior, as will be described later.

[0022] The coupler 10 shown in Figures 1(a) and 1(b) connects the ends of two opposing rebars 4L and 4R, preventing loosening of the threads and realizing an extended rebar that transmits axial force. This coupler 10 includes a main tube 11 to which the end of one of the rebars 4L is friction-welded, and a secondary tube 12 that is threadedly fitted into the main tube 11 on the opposite side of the friction-welded side of a blind hole 5H formed along the axis of the main tube 11. Therefore, the coupler 10 brought to the construction site is a simple two-component structure: a component (main tube 11 with rebar 4L) already integrated with the rebar 4L, and another component (secondary tube 12) that is independent of the other rebar 4R. While both are rigid metal bodies, the main tube 11 and secondary tube 12 are generally cast for reasons that will be explained later.

[0023] On the friction welding side of the blind hole 5H, a blind hole female thread 5F (pitch P5=P4) is formed into which the tip of the screw joint 4T (pitch is expressed as P4, the same applies below) of the other reinforcing bar 4R is screwed, and on the anti-friction welding side of this blind hole 5H, a blind hole female thread 5F (pitch P5=P4) is formed which is concentric with the blind hole female thread 5F but has a larger diameter (expanded diameter) than the blind hole female thread 5F and has a pitch P5 different from P5. 9F (=P4+2mm ミリメートル It is equipped with an expanding female screw 9F (set to 9F).

[0024] The secondary cylinder 12 is provided with a sleeve portion 8 having a sleeve portion male thread 8M that screws into the enlarged diameter female thread 9F, and a nut portion 13 that is coaxial with the sleeve portion 8 and is integrally formed at the end of the sleeve portion 8. The sleeve portion male thread 8M is engaged with the enlarged diameter female thread 9F, so that the pitch P 8M (=P 9F The nut portion 13 is provided with a female thread 13F of the nut portion, which is threaded with the threaded joint 4T of the reinforcing bar 4R and has the same phase as the pitch P5 of the female thread 5F of the pocket hole (pitch P 13F The sleeve hole 8H of the sleeve portion 8 also has a sleeve portion female thread 8F (pitch P 8F =P 13F ) is formed. As shown in FIG. 1(a), the sleeve hole female thread 8F may be connected to the nut portion female thread 13F. Incidentally, as for the pitches of each, as mentioned above, P4 = P5 = P 8F =P 13F , P 8M =P 9F =P4+2mm (2mm is an example).

[0025] The end of the rebar is the cut surface shown in Fig. 2(b), but the welded portion of the rebar that was the subject of friction welding has a roughly hollow ring-shaped burr 1 as shown in Fig. 2(a). The welded portion of the main cylinder 11 also has a roughly hollow ring-shaped burr 2 as shown in Fig. 1(a), but it is generally small.

[0026] The main cylinder 11 is a cylinder with an outer diameter about 1.5 times that of the rebar, as shown in Fig. 3, and the outer shape of a part of it, the left cylinder 11C, is a polygonal (hexagonal in the figure) facet for taking counter torque, and torque is easily applied with a wrench (not shown) hooked onto the polygonal (hexagonal in the figure) facet formed on a nut portion 13 of a part of the secondary cylinder 12, the external view of which is shown in Fig. 4. Incidentally, the length of the coupler formed by applying the secondary cylinder 12 to the main cylinder 11 requires at least 4 to 6 pitches of meshing at one point when targeting, for example, a D35 (nominal diameter approximately 35 mm) rebar 4R, and the total dimension of the main cylinder 11 and secondary cylinder 12 of this coupler when combined (meshed) is at most about 200 mm.

[0027] Before discussing the rebar joining operation, let's briefly introduce the well-known friction welding process that precedes the process. Unlike couplers that butt the opposing rebar ends together and fasten them with numerous set screws (such as U.S. Patent No. 5,046,878, mentioned in the prior art section), this coupler presses the main tube 11 and rebar 4L together at their butt joints and uses the heat generated by their relative high-speed rotation to crimp the contact points. Since this process cannot be performed on-site, it is performed in a well-equipped factory after the rebar has been manufactured, based on the building design documents (drawings), before shipping. This allows the rebar 4R, which is much longer than the coupler, to be threaded into the coupler with a gentle rotation, while the secondary tube 12, which is much shorter and easier to handle, can be firmly joined and locked with only a gentle rotation followed by a strong over-rotation, as described below.

[0028] Incidentally, the female thread of the pocket hole 5F and the female thread of the nut 13F are normally right-hand threads, but they are provided with a sufficient number of threads (for example, 4 to 6) to engage with the threads 4T of the rebar 4R (for example, the female thread of the pocket hole 5F in Figure 1(a) is drawn with only three threads to avoid making it horizontal for convenience of drawing), so even if a specified axial force is applied, there will be no shortage of interlocking threads.

[0029] As shown in Figures 5(c) and (d), which follow Figures 5(a) and (b), the secondary tube 12 is placed facing the main tube 11 to which the rebar 4L is friction-welded, and as shown in Figure 10 below, the paint mark 3 applied in advance for temporary setting is used as a guide. At this point, the blind hole female thread 5F, the sleeve female thread 8F, and the nut female thread 13F become a series of right-handed threads that are concentric and have the same pitch and phase (see Figure 5(c) in particular). Therefore, by rotating the main tube 11 to which the rebar 4L is pressure-welded or the rebar 4R, the rebar 4R, which has a right-handed thread, can be easily screwed into the coupler (see Figure 6). Note that if a phase shift occurs between the main tube and the secondary tube during the rotation (threading) of the rebar 4R or the main tube 11, preventing the rebar 4R from threading, a rotational misalignment prevention sleeve, as described below, can be used. This is a sleeve body 7 with a hexagonal hole portion 11D and a circular hole portion 6 connected as shown in Figures 7(a) and (b), which is stored on the reinforcing bar 4R and then placed over the round body portion of the main cylinder 11 and the nut portion 13 of the secondary cylinder 12, and a locking screw 7a is driven into the round body portion to prevent unexpected movement.

[0030] In applying the paint mark 3 (see Figure 10), the number of unengaged threads between the sleeve portion male thread 8M of the sleeve portion 8 and the expanded diameter female thread 9F on the side opposite the friction welding side of the pocket hole 5H is set to 2 or 3, allowing for at least one pitch of rightward or leftward movement of the secondary tube 12. In other words, a margin of at least one pitch of rightward or leftward movement is left to allow for a creaking operation (two threads are left in Figures 6, 7, 8 and 10). The above operations complete the pre-makeup process (see Figure 8).

[0031] If the reinforcing bar 4R is left screwed into the main tube 11, the reinforcing bar 4R will not be locked to the main tube 11, so the following operation is performed. As shown in FIG. 1, the male thread 8M of the sleeve of the secondary cylinder 12 has a pitch P which is different from the pitch P4 of the thread joint 4R of the reinforcing bar. 8M is formed, e.g., P 8MThe dimensions are: =P4+2mm. The 2mm difference is intended to allow for creaking, and also to allow for the ability to absorb several pitches of the rebar's pitch forming tolerance (for example, ±0.2mm). It goes without saying that the 5F blind hole female thread will have the necessary number of engagements for fastening, provided that the rebar allows for the forming tolerance of the thread pitch, taking into account the wear of the forming rolls.

[0032] As shown in Figure 9, a longitudinally extending slit 15 is formed in the outer casing of the cap screw 5 of the main tube 11, allowing for viewing of the tip position of the inserted rebar 4R. Furthermore, a similarly shaped slit 16, shown by the dashed line, may be formed opposite this slit for easier viewing. Therefore, by looking into the slits 15 and 16, it is possible to confirm that the end of the threaded rebar 4R has reached the designated position on the female thread 5F of the cap screw 5, as shown in Figure 11. This operation automatically confirms that the number of interlocking threads required for the joints 4 to 6 described above has been achieved. The rebar 4R is now embraced by the main tube 11, and the alignment between the main tube 11 and the rebar 4R is also achieved. Then, from the position shown in Figure 8, the secondary tube 12 is rotated clockwise and moved in the direction of arrow 17 shown in Figure 1(a) to approach the main tube 11. At this time, the minimum screwing amount required to maintain fastening force is ensured for the reinforcing bar 4R in all of the pocket hole female thread 5F, the sleeve portion female thread 8F, and the nut portion female thread 13F, making it possible to transmit the desired axial force.

[0033] With this configuration, a desired torque sufficient to maintain fastening strength is applied to the hexagonal nut portion 13 of the secondary cylinder 12, and the secondary cylinder 12 is over-rotated while receiving a reaction force from the left body 11C of the main cylinder 11. This causes frictional force (creation of creak) on the contact tooth surfaces resulting from the difference in pitch between the nut portion female thread 13F of the nut portion 13, into which the thread joint 4T of the rebar is threaded, and the sleeve portion male thread 8M of the secondary cylinder 12, thereby preventing unintended rotation or axial displacement of the rebar. The coupler's structure makes it ideal for use in joint construction (not shown), etc.

[0034] However, it is not easy to align the phase of the sleeve female thread 8F, which engages with the expanded female thread 9F of the cap screw hole in the main cylinder 11, with the phase of the nut female thread 13F through cutting (machining) operations. That is, while cutting (molding) the threads is easy, cutting the threads while matching the phase is extremely difficult. To ensure this, casting is used. The molding efficiency is dramatically improved by arranging the thread-like core so that the phases are aligned, providing a reference wall (reference surface) to be set as the positive end, and then abutting the end against this to determine not only the position but also the angular orientation. This is because, as can be seen in Figure 1(a), it is necessary to achieve a consistent phase for all threads.

[0035] Returning to the main subject, we will try to rotate the secondary cylinder 12, but if the sleeve body 7, which has a hexagonal hole portion 11D and a circular hole portion 6 connected together, is hung as shown in Figure 7(a), it will be retracted onto the right side of the rebar 4R or removed from the opposite end of the rebar 4R, and then the secondary cylinder 12 will be rotated rightwards to the left as shown by arrow 17 in Figure 1(a). The male thread 8M of the sleeve portion of the secondary cylinder 12 will follow the enlarged female thread 9F of the main cylinder 11. Meanwhile, the female thread 13F of the nut portion will also thread along the thread joint 4T of the rebar 4R. However, if the male thread 8M of the sleeve portion moves along the enlarged female thread 9F by one pitch P, 8M (=P 9F =P4 + 2mm), the thread of the rebar 4R, which is 2mm shorter, will have reached one pitch of thread advancement, and this becomes a hindrance; with the secondary tube 12's gentle rotation up to that point, the thread advancement of the sleeve male thread 8M along the expanding female thread 9F of the main tube 11 is hindered due to the rigidity of the secondary tube 12. Therefore, if the secondary tube 12 is forcibly rotated clockwise (over-rotating), the nut female thread 13F will apply a squealing torque to the thread of the rebar 4R, 4T, before the sleeve male thread 8M has completed one pitch of thread advancement along the expanding female thread 9F. The thread of the rebar 4R, 4T, will not even allow the secondary tube 12 to rotate in the reverse direction, and will either damage the nut female thread 13 with which it is threaded (due to tooth surface interference), or the nut female thread 13 will damage the thread of the rebar 4R, 4T, or they will damage each other. As shown in FIG. 17(a), the same applies when the sub-cylinder 12 is moved to the right 18. Also, P4=P5=P 8F =P13F , P 8M =P 9F The same can be said if =P4-2mm, so duplicated information will be omitted below.

[0036] A simple explanation will be given below using specific examples. 8M =P 9F =19mm, P4=P 13F = 17 mm, and the secondary cylinder 12 is first rotated 1 / 4 turn (π / 2 rad rotation). The male thread 8M of the sleeve of the secondary cylinder 12 follows the expanded female thread 9F of the main cylinder 11 and moves 4.75 mm. Meanwhile, the female thread 13F of the nut should move 4.25 mm following the rebar 4R. As long as the difference (difference) of 4.75 - 4.25 = 0.5 mm is within the range of the sum of the backlash on the male thread 8M side of the sleeve and the backlash on the female thread 13F side of the nut, the secondary cylinder 12 can move to the left.

[0037] Suppose the secondary cylinder 12 is rotated another 1 / 12 turn to the right (1 / 3 turn from the start of the clockwise rotation, or 2π / 3 rad). The male thread 8M of the sleeve of the secondary cylinder 12 follows the female thread 9F of the main cylinder 11, moving a total of 6.33 mm. Meanwhile, the female thread 13F of the nut should move a total of 5.67 mm. When the difference (6.33 - 5.67 = 0.66 mm) can no longer be absorbed by the sum of the backlash on the male thread 8M of the sleeve and the female thread 13F of the nut, the secondary cylinder 12 is becoming unable or no longer able to move left. Light rotation of the secondary cylinder 12 is not permitted, and if torque exceeding that of the 1 / 12 turn just performed is applied, the male thread 8M of the sleeve will follow the female thread 9F of the main cylinder 11, while the female thread 13F of the nut will creak against the 4M thread joint of the 4R rebar. The greater the torque, the more deformation (roughening) occurs on the mating tooth surfaces, and the resulting creaking causes the coupler to lock. This creaking occurs on any or all of the mating thread surfaces within the coupler. Therefore, locking is achieved by a gentle rotation of only one component (the secondary barrel 12), followed by a strong rotation. At this time, the secondary barrel 12 is subjected to axial tension, so it goes without saying that it must be able to withstand this axial force.

[0038] Incidentally, the rebar 4L that is the target of the friction welded rebar can be of a different diameter than the rebar 4R (see Figure 13(a)), or it can be the bamboo-knot rebar 4B mentioned at the beginning (see Figure 13(b)), which does not require screw-like behavior. This is convenient because it allows for variety in the rebars used, prevents excessive use of rebar material, and helps with inventory adjustment.

[0039] Incidentally, when threading the rebar 4R shown in Figure 12 into the main tube 11, it should be noted that if the secondary tube 12 is threaded before it is engaged, the secondary tube 12 will not be able to thread into the main tube 11 due to the difference in pitch. Therefore, with the secondary tube 12 engaged with the main tube 11, a substitute for the rebar 4R (a short item approximately 300 mm long) or a replica is threaded from the secondary tube 12 into the main tube 11. This automatically achieves phase alignment. In this case, the number of unengaged threads between the sleeve male thread 8M and the enlarged female thread 9F is set to two or three, and the above-mentioned paint mark 3 (see Figure 10(a)) is applied to the boundary between the main tube 11 and the secondary tube 12. This allows the secondary tube 12 to move to the right or left by at least one pitch. Needless to say, the substitute for the rebar 4R is then removed.

[0040] Incidentally, the position of the left barrel 11C (see FIG. 1(b)) which is a polygonal (hexagonal in the drawing) facet for taking the counter torque of the main barrel 11 may be the center barrel 11E as shown in FIG. 16. It may be in a position where the sleeve body 7 shown in FIG. 7 or a device with the same function can be attached without getting in the way.

[0041] Incidentally, Figures 14 and 15 show some examples of fastening work performed at construction sites. Although the figure is small, Figure 14 shows an example of the process of repeating (i) through (iv) from the state corresponding to Figure 1(b) to reach (v). The subscripts 1, 2, 3, etc. after the reference numerals indicate the order in which the fasteners are introduced. It goes without saying that this is not a limitation, and it is also possible to increase the length by introducing other types of couplers in intermediate positions. Figure 15(a) is an example corresponding to Figure 13(a), and it is natural to reduce or increase the size of the coupler 10 as necessary to match the thickness of the applicable rebar. Figure 15(b) is an example corresponding to Figure 13(b).

[0042] The above description concerns coupler 10 shown in the movements of Figures 1, 6, and 12, in which secondary tube 12 is screwed into main tube 11. However, we propose a different example, in which secondary tube 12X is screwed onto the outer surface, i.e., periphery, of main tube 11X, as shown in Figures 18, 19, and 20, as a different coupler 10X.

[0043] The coupler 10X comprises a main cylinder 11X and a secondary cylinder 12X that is externally fitted and screwed thereto, and on the friction welding side of a pocket hole 5H drilled along the axis of the main cylinder 11X, there is a pocket hole female thread 5F into which the screw joint 4T of the other reinforcing bar 4R is screwed, and on the opposite friction welding side of the outer circumferential surface of the main cylinder 11X, there is provided an enlarged male screw 9M that is concentric with the pocket hole female thread 5F but has a larger diameter than the pocket hole female thread 5F. The female thread 8FX of the sleeve portion of the secondary cylinder 12X that screws into this enlarged male screw 9M has a pitch P4 different from the pitch P4 of the screw joint 4R of the reinforcing bar. 8FX The fastening principle and behavior of this coupler 10X are almost the same as the previous example, so we will not repeat the explanation. However, as mentioned above, P4 = P5 = P 13F , P 8FX =P 9M =P4+2mm. Or, P4=P5=P 13F , P 8FX =P 9M 18, it can be seen that the creaking lock is achieved by the left row 17X in FIG. 19 and the right row 18X in FIG.

[0044] The above explanations reveal the following: The rebar to be connected is joined using simple components and can be fastened by gently rotating the easy-to-handle secondary cylinder followed by a strong rotation. If the rebar has threads within the molding tolerances, uniformity in the fastening of the rebar can be achieved even if there is variation in the thread pitch. Because there is a difference in pitch between the expanding female thread 9F and expanding male thread 9M of the coupler's main cylinder 11 and the female thread 13F of the nut that engages with the rebar 4, the increased surface contact pressure of the threads during threading increases the frictional force acting on the surface of the threads. If roughness appears on the surface of the threads due to creaking caused by compression, further threading or retraction is prevented, and the over-threaded threads will not come loose unless a reverse torque exceeding the load torque is applied. It also prevents the need to lengthen couplers or increase the tightening load to ensure perfect fastening. This reduces the burden of torque management, which is effective in preventing rattle and slippage. Furthermore, it allows for the rebar diameter to be gradually reduced or increased depending on the application area of ​​the building, and deformed rebar can be changed from threaded joints to bamboo joints, reducing the amount of rebar used and promoting the use of stock. 4R rebar, which is much longer than the coupler, can be threaded into the coupler with a gentle turn, and a firm connection and lock can be achieved with just a gentle turn of the secondary tube, which is much shorter and easier to handle than the rebar, followed by a strong over-turn. The coupler's structure also makes it ideal for use in joint construction. Furthermore, the expanding female screw or expanding male screw has a pitch that is larger or smaller than the pitch of the thread of the reinforcing bar, and this pitch difference results in a large frictional force acting on the surface of the screw due to the surface contact pressure of the screw, resulting in a strong fastening due to the creaking between the screws. Furthermore, if a reaction force relief surface is formed on the outer surface of the main cylinder, it becomes easier to remove the reaction force when a desired torque is applied to the nut portion. If a slit extending in the longitudinal direction is formed in the main cylinder, the position of the tip of the inserted rebar can be confirmed. If a slit of approximately the same shape is formed at the opposite position to this slit, it can be seen through, making it easier to confirm the position of the tip of the inserted rebar.

[0045] It should be noted that there is no intention to exclude the use of grout (mortar, adhesive, thread locking agent, etc.) in combination. In other words, this does not mean that grout, etc., should not be used in the configuration of this invention, but rather that in most cases, the injection of grout is not necessary in principle, and it goes without saying that it may be used in a known manner. [Explanation of symbols]

[0046] 1: Burrs on rebar, 2: Burrs on main tube, 3: Paint mark, 4: Rebar, 4T: Screw knot, 4B: Bamboo knot, 4L, 4R: Screw knot rebar, 5H: Head hole, 5F: Head hole female thread, 6: Circular hole portion, 7: Sleeve body, 7a: Locking screw, 8, 8X: Sleeve portion, 8H: Sleeve hole, 8M: Sleeve male thread, 8F, 8FX: Sleeve female thread, 9F: Expanding female thread, 9M: Expanding male thread, 10, 10X: Coupler, 11, 11X: Main tube, 11C: Left body, 11D: Hexagonal hole portion, 11E: Middle body, 12, 12X: Secondary tube, 13: Nut portion, 13F: Nut female thread, 15, 16: Slit, 17, 17X: Left arrow, 18, 18X: Right arrow.

Claims

1. A coupler capable of fastening a first reinforcing bar and a second reinforcing bar in the axial direction, The coupler is a main cylinder having one axial end to which the first reinforcing bar is friction-welded and another axial end to which an opening is provided; a secondary cylinder that can be inserted through an opening of the main cylinder, The main cylinder is a first female screw portion formed on a part of the inner periphery; a second female thread portion formed on an inner periphery closer to the other end than the first female thread portion, The secondary cylinder is a male screw portion formed on an outer periphery thereof and adapted to be threadedly engaged with a second female screw portion of the main cylinder; A female screw portion formed on an inner periphery and threadedly engaging with the thread of the second reinforcing bar, the first female screw portion of the main cylinder and the female screw portion of the sub-cylinder are configured to have the same pitch and phase; The second female screw portion of the main cylinder and the male screw portion of the sub-cylinder are threadedly engaged with each other, and the first female screw portion of the main cylinder and the female screw portion of the sub-cylinder are threadedly engaged with the thread of the second reinforcing bar, The thread pitch of the male thread portion of the secondary cylinder is configured to be different from the thread pitch of the second reinforcing bar. coupler.

2. The male thread portion of the secondary cylinder is formed with a male thread having a pitch larger than the pitch of the thread joint of the second reinforcing bar.

2. The coupler of claim 1.

3. The male thread portion of the secondary cylinder is formed with a male thread having a pitch smaller than the pitch of the thread joint of the second reinforcing bar, 2. The coupler of claim 1.

4. A coupler capable of fastening a first reinforcing bar and a second reinforcing bar in the axial direction, The coupler is a main cylinder having one axial end to which the first reinforcing bar is friction-welded and another axial end to which an opening is provided; a secondary cylinder having an opening into which the primary cylinder can be inserted, The main cylinder is a male thread portion formed on the outer periphery; a female screw portion formed on the inner periphery thereof, The secondary cylinder is a first female screw portion formed on an inner peripheral portion of the main cylinder and adapted to be threadedly engaged with a male screw portion of the main cylinder; a second female screw portion formed on an inner peripheral portion opposite to the main tube side and adapted to screw into a thread of the second reinforcing bar; the female screw portion of the main cylinder and the second female screw portion of the sub-cylinder are configured to have the same pitch and phase; The male screw portion of the main cylinder and the first female screw portion of the secondary cylinder are threadedly engaged, and the female screw portion of the main cylinder and the second female screw portion of the secondary cylinder are threadedly engaged with the thread of the second reinforcing bar, The thread pitch of the male thread portion of the main cylinder is configured to be different from the thread pitch of the second reinforcing bar. coupler.

5. The male thread portion of the main tube is formed with a male thread having a pitch larger than the pitch of the thread joint of the second reinforcing bar.

5. The coupler of claim 4.

6. The male thread portion of the main tube is formed with a male thread having a pitch smaller than the pitch of the thread joint of the second reinforcing bar.

5. A coupler according to claim 4.

7. A reaction force chamfering surface is formed on the outer surface of the longitudinal center portion of the main cylinder when a desired torque is applied to the sub-cylinder.

5. The coupler according to claim 1 or 4.

8. The first reinforcing bar and the second reinforcing bar have different nominal diameters.

5. The coupler according to claim 1 or 4.

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