Coupler for threaded joint steel bar and threaded joint steel bar provided with same

Abstract

The invention provides a coupler of a threaded joint steel bar, which can easily perform torque management without filling a sleeve with grout. A coupler (10) is provided with a main tube (11) and sub-tubes (12, 13). An axial hole formed in the main tube is a through threaded hole (H5) into which a threaded section (M4) of a reinforcing steel bar is screwed, and peripheral threads (6, 7) are formed on the outer peripheries of the left and right half bodies of the main tube. The thread has a thread pitch (P6, P7) different from a thread pitch (P4) of a thread section (M4) of the reinforcing steel bar. Nut parts (14, 15) are formed on one side end of sleeve parts (8, 9) covering the outer peripheries of the left and right half bodies of the main cylinder, sleeve inner peripheral threads (F8, F9) screwed with the outer peripheral threads (6, 7) are arranged in the sleeve parts (8, 9), and nut part inner threads (F14, F15) screwed with the threaded joint (M4) of the reinforcing steel bar are formed in the nut parts.

Description

Technical Field

[0001] The present invention relates to a coupler for threaded steel bars, and more particularly, to a coupler that prevents the steel bars and the coupler from loosening in the coupler into which the ends of opposing steel bars are inserted, and that is tightened in order to lengthen the steel bars that transmit axial force, and also to a threaded steel bar having the coupler. Background Art

[0002] When using reinforced concrete to construct buildings or civil engineering structures, considering the convenience of transportation from the factory to the construction site, special-shaped steel bars (threaded knot steel bars or bamboo knot steel bars) used as concrete reinforcement materials are manufactured into a standard specification of, for example, 12 meters.

[0003] However, when in use, in order to match the size of the building to which it is applied or the length at the application location, additional steel bars are often added at the construction site. Both threaded segmented steel bars and bamboo segmented steel bars (bamboo segmented steel bars are not the subject of the present invention) are formed by gradually deforming the diameter of the rollers formed in the rolling process, but the rollers will gradually become rough and worn by a slight amount. Although the surface roughness can be removed by surface grinding and continued to be used, the reduction in roller diameter is inevitable, and the pitch will vary slightly depending on the manufacturing period. On the other hand, the tooth shape formed in the coupling hole of the coupler is cast and formed while matching the thread pitch of the conventional size of the steel bar and taking into account the forming tolerance of the steel bar. Therefore, although the pitch difference between the coupler and the steel bar can be absorbed to make them mesh, a meshing gap will inevitably remain.

[0004] The gaps between the tooth surfaces are filled with grout (e.g., mortar) to prevent shaking, or small threads are erected from the outside of the coupler to the surface of the steel bar to prevent it from falling off. Examples of the former are shown in Patent Documents 1 and 2, and examples of the latter are shown in Patent Documents 3 and 4. In any case, the length of the coupler is increased and the tightening load is increased in the hope of perfect tightening. Therefore, people are eagerly looking forward to the emergence of a coupler that can easily perform torque management (realize tightening at low torque and make the tightening force uniform) that can prevent shaking or falling off.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: U.S. Patent No. 4,666,326

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2018-178365

[0009] Patent Document 3: U.S. Patent No. 5046878

[0010] Patent Document 4: U.S. Patent No. 7107735 Summary of the invention

[0011] Technical issues

[0012] The present invention is made in view of the above situation, and its purpose is to provide a coupler that utilizes the mutual compression of thread teeth to join opposing threaded steel bars without introducing grout or thread locking agent into a sleeve, and a threaded steel bar equipped with the coupler.

[0013] Technical Solution

[0014] Reference Figure 1 The first invention of the threaded steel bar coupler is applied to a coupler that prevents the steel bars and the coupler from loosening in the coupler into which the ends of the opposing steel bars 4L and 4R are inserted, and tightens the steel bars for transmitting axial force in order to lengthen them. The threaded steel bar coupler is characterized as follows.

[0015] The coupler 10 comprises a main tube 11 and two sub-tubes 12 and 13 which are symmetrical and threadedly connected to the outer circumference of the left and right halves of the main tube 11.

[0016] The axial hole formed in the main tube 11 is a longitudinal threaded hole H5 into which the threaded sections M4 of the steel bars 4L and 4R are screwed.

[0017] On the outer periphery of the left and right half bodies, outer peripheral threads 6 and 7 are formed which are concentric with the longitudinal threaded hole H5 and have a larger diameter than the longitudinal threaded hole H5, and end external threads M6 and M7 are provided in the outer peripheral threads 6 and 7.

[0018] The end external threads M6 and M7 have a phase that matches the phase of the internal thread F5 of the longitudinal threaded hole H5, and have pitches P6 and P7 that are different from the pitch P4 of the threaded section M4 of the reinforcing bars 4L and 4R.

[0019] The secondary cylinders 12 and 13 include: sleeve portions 8 and 9 having end internal threads F8 and F9 threadedly coupled to end external threads M6 and M7, and nut portions 14 and 15 coaxial with the sleeve portions and integrally formed at one end of the sleeve portions.

[0020] The nut portions 14 and 15 are provided with nut portion internal threads F14 and F15 on which the threaded sections M4 of the reinforcing bars 4L and 4R are threadedly engaged and which have phases that coincide with the phases of the end internal threads F8 and F9 .

[0021] like Fig.12As shown, the threaded reinforcing bar coupler of the second invention is a member having a main cylinder 11A, secondary cylinders 12A, 13A with reversed male and female threads of the main cylinder 11 and secondary cylinders 12, 13, so that desired locking is achieved by squeezing them.

[0022] like Figure 6 As shown, end external threads M6 and M7 having pitches P6 and P7 larger than the pitch P4 of the thread section M4 of the steel bar are formed on the outer periphery of the left and right half bodies of the main tube 11.

[0023] In addition, if Fig.11 As shown in (b), end external threads M6 and M7 having pitches P6 and P7 smaller than the pitch P4 of the threaded section M4 of the reinforcing bars 4L and 4R are formed on the outer periphery of the left and right half parts of the main tube 11.

[0024] like Fig.12 As shown, the left and right half body inner holes of the main tube 11A are formed with end internal threads F6 and F7 whose pitches P6 and P7 are larger than the pitch P4 of the threaded segments M4 of the reinforcing bars 4L and 4R. In addition, the left and right half body inner holes of the main tube 11A are formed with end internal threads F6 and F7 whose pitches P6 and P7 are smaller than the pitch P4 of the threaded segments M4 of the reinforcing bars 4L and 4R.

[0025] like Figure 4 As shown, a reaction force acting surface 11C is formed on the outer surface of the longitudinal center portion of the main cylinder 11 when a desired torque is applied to the nut portions 14 and 15 .

[0026] A slit 17 extending in the axial direction is formed in the middle of the main tube 11 in the longitudinal direction so as to allow viewing of the tip position of the inserted reinforcing bars 4L, 4R. A slit 18 of the same shape is also formed at a position opposite to the slit 17.

[0027] like Fig.11 As shown in (c), the end of the reinforcing bar on the opposite side of the coupler has a bend 25 that functions as an anchor plate.

[0028] Effects of the Invention

[0029] According to the first invention, since the coupler is composed of a main tube and two auxiliary tubes in a left-right symmetrical posture, the connected steel bars can be joined by the same components and tightened by the same torque load operation. If the steel bar has a thread section within the forming tolerance, even if there is a difference in the pitch of the thread section within the manufacturing tolerance, the uniform tightening of the steel bar can be achieved. Since there is a difference in pitch between the outer peripheral threads of the left half body and the right half body of the main tube and the thread section of the steel bar, as the thread advances, the surface contact pressure of the thread teeth with a smaller pitch increases, so that the friction force acting on the surface of the thread surface increases. When the surface of the thread teeth becomes even slightly rough due to the extrusion caused by pressure, the subsequent screw advance or retreat is prevented, and the thread teeth will not be released from the over-threaded engagement unless the counter-torque corresponding to the load torque acts. According to the second invention, since the pitch difference is made between the end internal threads of the left and right half body inner holes of the main tube and the threaded section of the steel bar, as the thread advances, the surface contact pressure of the thread teeth with a smaller pitch increases, so that the friction force acting on the surface of the thread surface increases. When the surface of the thread teeth becomes even slightly rough due to the extrusion caused by the pressure, the subsequent advancement or retreat is prevented.

[0030] Since an outer peripheral thread with a pitch larger than the pitch of the threaded section of the steel bar or an outer peripheral thread with a smaller pitch is formed on the outer periphery of the left half body and the right half body of the main tube, the friction force acting on the surface of the thread is greater than the surface contact pressure of the thread by utilizing the pitch difference, thereby utilizing the extrusion of the threads to perform a firm fastening. Further, the convenience of fastening is explained as follows, that is, in the coupler of the present invention, fastening can also be performed without rotating the threaded section steel bar.

[0031] Since an end internal thread with a pitch larger than the pitch of the thread section of the steel bar or an end internal thread with a smaller pitch is formed in the inner holes of the left half body and the right half body of the main tube, the pitch difference is utilized to make the friction force acting on the surface of the thread greater than the surface contact pressure of the thread, thereby utilizing the extrusion of the threads to achieve firm fastening.

[0032] When a reaction force acting surface is formed on the outer surface of the center body which is the center part in the longitudinal direction of the main tube, it is easy to apply the reaction force when the desired torque is applied to the nut part. When a slit extending in the axial direction is formed in the center body which is the middle part in the longitudinal direction of the main tube, the front end position of the inserted steel bar can be confirmed. When a slit of the same shape is also formed at a position opposite to the slit, it can be seen through, making it easy to confirm the front end position of the inserted steel bar.

[0033] By providing a bent portion at the anti-coupler side end of the reinforcing bar, the function of the anchor plate can be exerted. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a completed diagram of the steel bar fastening performed using the coupler for threaded steel bars of the first invention.

[0035] Figure 2 This is a process diagram of the first half of the steel bar tightening process using a coupler for threaded steel bars.

[0036] Figure 3 This is a process diagram of the second half of the steel bar tightening process, including the meshing of two steel bars and the pitch adjustment process using a gauge.

[0037] Figure 4 This is a three-dimensional diagram of the main barrel.

[0038] Figure 5 It is a single stereoscopic image and a partially enlarged image of a threaded steel bar.

[0039] Figure 6 It is a longitudinal section view of the main cylinder.

[0040] Figure 7 It is a three-dimensional diagram of the appearance of the secondary cylinder.

[0041] Figure 8 It is a longitudinal sectional view of the secondary cylinder.

[0042] Fig. 9 It is a thread end view showing the meshing starting point Q in the secondary cylinder.

[0043] Fig.10 It is a process drawing for setting equal pitch using a gauge.

[0044] Fig.11 It is a process diagram of the second half of the process of tightening steel bars with different pitch shapes, and an application diagram for steel bars with anchoring function.

[0045] Fig.12 This is a completed view of the steel bar fastening of the second invention in which the yin and yang of the threads of the main tube and the auxiliary tube are reversed. DETAILED DESCRIPTION

[0046] The following is a detailed description of the threaded steel bar coupler of the present invention based on the accompanying drawings showing its embodiment. Figure 2 (a) The opposed threaded steel bars 4L and 4R are as shown in FIG. Figure 3 (c) is used for fastening. That is, whether or not grouting is used, the purpose is to firmly join the reinforcing bars by squeezing the threads together.

[0047] Figure 2The coupler 10 shown in (a) inserted into the opposite ends of the two reinforcing bars 4L and 4R prevents the loosening of the threaded connection with the reinforcing bars 4 and realizes the elongation of the reinforcing bars that transmit the axial force. The coupler 10 has a main tube 11 and secondary tubes 12 and 13 arranged in a bilaterally symmetrical manner, that is, for each reinforcing bar. Therefore, the coupler 10 is an extremely simple and small-volume coupler composed of three components. In addition, all the components are rigid bodies made of metal, but as will be described later, they are cast products in principle.

[0048] The main tube 11 has an outer diameter that is about 1.4 times that of the steel bar, for example. Figure 4 The central body 11C of the main body 11 is a polygonal surface (hexagonal deformation surface in the figure) capable of applying a counter torque when tightening, and the outer surfaces of the left and right halves are formed with the rear number of external threads M6 and M7. The axial hole formed in the main body 11 is formed to be in contact with the threaded section M4 of the steel bars 4L and 4R even if there is a meshing gap (including the rear gap) (refer to Figure 5 ) through threaded hole H5 (refer to Figure 4 ).

[0049] Incidentally, the through threaded hole H5 is generally right-hand threaded in both the left and right half bodies, but has a sufficient number of internal threads F5 for meshing engagement with the thread teeth M4 of the reinforcing bars 4L and 4R that exert a predetermined fastening performance (see Figure 6 , for example, 5 to 6). The pitch of the thread teeth from one opening end to the other opening end of the through threaded hole H5 is constant, regardless of whether the spiral in the through threaded hole H5 is interrupted (not shown) or uninterrupted (in Figure 6 The threaded hole H5 is not interrupted at the position of the peephole of the E part in the left and right halves. The thread phases are the same. That is, even if there is only one steel bar 4, it can be screwed through the threaded hole H5 (refer to Figure 2 (c)). This is because the threaded hole H5 and the nut internal threads F14 and F15 of the aforementioned sub-tubes 12 and 13 are as follows. Figure 3 (b) shows that the secondary cylinders 12 and 13 are covered deeply to form threads with the thread phase consistent. In addition, the prefix H of the reference numerals refers to the hole portion, M represents the external thread, F represents the internal thread, and P represents the pitch, which is also convenient for understanding the components or parts later.

[0050] Furthermore, if the forming tolerance of the thread pitch is allowed in consideration of the wear of the forming roller, it goes without saying that the threaded hole H5 is the number of internal threads F5 (see Figure 6That is, regardless of whether the steel bar is a product with the maximum allowable pitch or a product with the minimum allowable pitch, the internal thread F5 of the through threaded hole H5 in the main tube 11 is a spiral number within the range of conventional threaded engagement without mutual interference of the tooth surfaces on the basis of the meshing that satisfies the desired number of threads.

[0051] For example, when it comes to D35 (nominal diameter 35 mm, which is based on the Japanese steel bar standard (JIS G3112:2020) and corresponds to 36 mm in the Chinese steel bar standard (GB1499.2-2024)), the main tube 11 needs to be meshed for example by 5 to 6 pitches, a total of 12 pitches, and even if the steel bar end butt space E is increased (refer to Figure 6 ), the total length of the coupler is at most about 300mm.

[0052] like Figure 6 As shown, peripheral threads 6 and 7 are formed on the outer periphery of the left half body and the outer periphery of the right half body of the main tube 11. The peripheral threads 6 and 7 are concentric with the through threaded hole H5 and have a phase consistent with the phase of the through threaded hole H5, and have a pitch P4 (refer to Figure 5 ) Unequal pitches P6 and P7 (refer to Figure 4 and Figure 6 ). For this purpose, for example, the dimension P7=P4+2 mm is selected. In addition, the difference of 2 mm is given not only for the purpose of producing extrusion, but also for the purpose of absorbing the amount of several pitches even if a certain accumulation of pitch forming tolerances of the steel bars (for example, ±0.2 mm) is achieved.

[0053] The secondary cylinders 12 and 13 have Figure 7 The appearance shown in FIG. 1 and the outer periphery of the left half of the main tube 11 are covered respectively (refer to FIG. Figure 6 ) and the outer periphery of the right half body, and the nut parts 14, 15 coaxial with the sleeve part and integrally formed at one end of the sleeve part. The sleeve part is provided with the outer peripheral threads 6, 7 (refer to Figure 4 , Figure 6 ) The inner thread of the sleeve that engages with the F8, F9 (refer to Figure 2 (b) Figure 7 ), and the nut parts 14 and 15 are formed with nut internal threads F14 and F15 (refer to Figure 2 (b) Figure 7 , Figure 8 ). That is, the pitch P of the internal threads F14 and F15 of the nut portion is 14 , P 15 (Refer to Figure 3(c)) is equal to the thread pitch P4 in the minimum steel bar tolerance formed product (meaning the product according to the reference size of the production drawing). In addition, for the number of meshing threads of the nut internal threads F14 and F15 with the steel bar 4, the number of meshing threads that exert the tightening effect on the outer periphery of the left half body and the outer periphery of the right half body of the main cylinder 11 is allocated.

[0054] Therefore, if Figure 2 As shown in (b), a through threaded hole H5 and internal threads F14 and F15 of the nut portion are formed in the coupler 10. The internal threads F14 of the nut portion, the internal threads F5 of the through threaded hole H5 and the internal threads F15 of the nut portion form a threaded hole with a certain pitch P4, and the ends of the left and right steel bars 4L and 4R can be received.

[0055] like Figure 3 As shown in (b), as a result, the phases of all threads of the internal thread F5 of the threaded hole H5, the end external threads M6 and M7 of the outer peripheral threads 6 and 7, the inner peripheral internal threads F8 and F9 of the sleeve, and the internal threads F14 and F15 of the nut are the same. The same phase means that the rotation angle of the thread end is the same when the threads start to mesh. That is, the rotation here refers to the time point when the front end of the external thread falls into the opening of the internal thread and the time point when the meshing starts. Fig. 9 The same rotation angle at the start of meshing, that is, the same rotation angle position at the start of meshing means, for example, that the threaded engagement (helix) starting point Q makes the meshing start at the entry angle (for example, 2π / 3rad 120 degrees) from a point U based on a certain angle.

[0056] According to the thread group of this structure, by connecting the nut parts 14 and 15 (refer to Figure 7 ) to apply the desired torque that can maintain the tightening strength, and on the polygonal cross-section reaction torque application surface 11C (refer to Figure 4 ) while taking the counter force, the screw is rotated to advance, so that the internal threads F14 and F15 of the nut parts 14 and 15 are pressed tightly against the threaded sections M4 of the reinforcing bars 4L and 4R to generate friction (refer to Figure 3 (c), meaning that extrusion occurs). Thus, unintentional rotation or axial displacement of the reinforcing bar can be prevented.

[0057] In addition, if Figure 6 As shown, a slit 17 extending in the axial direction is formed in the through threaded hole H5 located in the middle of the length direction of the main tube 11 so as to be able to see through the front end position of the inserted steel bars 4L and 4R. When a slit 18 of the same shape is also formed in the main tube 11 at a position opposite to the slit, the butt end of the steel bar 4 can be easily confirmed by looking through it, and the insertion depth of the steel bar will not be misjudged.

[0058] In addition, the outer peripheral threads 6 and 7 formed on the outer periphery of the left half body and the outer periphery of the right half body of the main tube 11 (see Figure 6 ) has a phase that is consistent with the phase of the internal thread F5 of the through-thread hole H5, or in the thread section M4 of the steel bar (refer to Figure 5 ) screwed into the nut with internal threads F14, F15 (refer to Figure 7 ) with the sleeve inner thread F8, F9 (refer to Figure 3 (b)) The phase consistency is not easy to achieve through cutting (machining) operations. Figure 3 It can also be seen in (b) that it is necessary to make all tooth surfaces initially mesh at the same time, but the processing to achieve this must not rely on casting. Since this is not directly related to the subject matter of the present invention, it will not be discussed here.

[0059] The following is a description of the steel bar tightening process. Figure 2 (a) A main tube 11 and two auxiliary tubes 12 and 13 are arranged at the connection part of two threaded steel bars 4L and 4R. The auxiliary tubes 12 and 13 can be of the same specifications (same nominal diameter, pitch, phase, etc.) and are arranged in a bilaterally symmetrical manner. Figure 2 As shown in (b), the inner threads F8 and F9 of the sleeve are meshed with the outer threads M6 and M7, and the secondary tube 12 is deeply threaded to one side of the main tube 11 so that the thread phases are consistent, and the secondary tube 13 is deeply threaded to the other side so that the thread phases are consistent. The central body 11C is an angular cross-section (refer to Figure 4 ), and the secondary cylinders 12 and 13 have a shape and size that cannot cover this position, but most of the left half body and the right half body are covered. The secondary cylinders 12 and 13 do not cover the slits 17 and 18, but are arranged close to each other. After the initial engagement, the threaded segment steel bar 4R is brought close to the threaded segment steel bar 4L (refer to Figure 2 (c)).

[0060] For example, Figure 3 As shown in (a), the front end 4Le of the threaded steel bar 4L protrudes from the assembled coupler 10 by about 1 pitch until the head is exposed, and the thread gauge 19 (refer to Fig.10 ) Maintain the continuity of the spiral of the thread. That is, prevent the phase misalignment. Figure 3 As shown in (b), the entire coupler 10 is moved (by rotating to the right). Since the internal thread F14 of the nut portion of the secondary cylinder 12, the internal thread F5 of the through-threaded hole H5 of the main cylinder 11, and the internal thread F15 of the nut portion of the secondary cylinder 13 are continuous, it is not difficult to move the threaded segment steel bar 4L. That is, the threaded segment steel bar 4R and the threaded segment steel bar 4L are kept at a predetermined gap E (see Figure 3(b)), and screw the coupler 10 toward the threaded steel bar 4R.

[0061] Probe peek slits 17, 18 (refer to Figure 4 ), and Figure 3 As shown in (b) and (c), it is confirmed whether the opposite ends of the threaded segment steel bars 4L and 4R are located in the through threaded hole H5 of the main tube 11. If confirmed, the auxiliary tubes 12 and 13 are rotated respectively so that the auxiliary tubes 12 and 13 are separated in the directions of arrows 21 and 22.

[0062] Therefore, the sub-tubes 12 and 13 move toward the outer threads 6 and 7, but the nut internal threads F14 and F15 try to move as if guided by the threaded segment steel bar. When the sub-tube is rotated 1 turn, for example, the movement amount guided by the outer thread 6 is 1 pitch P6. At the same time, since the sub-tubes 12 and 13 are screwed with the threaded segment steel bar 4R, they must move P4+2mm (=P6) (refer to Figure 6 ). Although the secondary cylinders 12 and 13 are rigid bodies, it is impossible to do anything. When the extrusion torque is applied to the thread teeth of the coupler 10, the internal threads F14 and F15 of the nut part screwed with the threaded section of the steel bar and the threaded section M4 of the steel bar 4R interfere with each other and are damaged, and the internal threads F14 and F15 of the nut part are in an extruded state due to the thread of the screwed steel bar 4R.

[0063] This means that not only further screwing in, but also backward (loosening) becomes impossible. In addition, when a tightening error is found, the thread teeth can be regenerated during the tightening release operation, even if it is not complete, but the locked state can be released.

[0064] Contrary to the above example, if P4 = P6 + 2 mm (ie, P6 = P4 - 2 mm), the sub-tubes 12 and 13 are rotated clockwise to Fig.11 As shown in (b), the nut moves in the direction of arrows 23 and 24. Since the internal threads F14 and F15 of the nut part are guided by the threaded bar 4R and try to move, the outer threads M6 and M7 are squeezed first.

[0065] The secondary cylinders 12 and 13 also try to move along the peripheral threads 6 and 7. This is because when the secondary cylinders 12 and 13 move along the external thread section M4 of the steel bar, for example, by one rotation, they must move along the peripheral thread 6 by a pitch of P6+2 mm.

[0066] As can be seen from these operation descriptions, even if any of the threaded segmented reinforcing bars 4L and 4R is moved in the axial direction, it is not necessary to rotate it for screwing in or screwing in. That is, tightening can be achieved simply by rotating the main tube 11 and the auxiliary tubes 12 and 13 .

[0067] The components that are indispensable for implementing the above actions are as follows. Figure 1 ,

[0068] A coupler in which the ends of opposing steel bars 4L and 4R of the same specification (same diameter, same pitch, same thread phase) are inserted into the coupler to prevent the steel bars and the coupler from loosening and to tighten the steel bars for transmitting axial force in order to lengthen them.

[0069] The coupler 10 comprises a main tube 11 and two sub-tubes 12 and 13 which are symmetrical and threadedly connected to the outer circumference of the left and right halves of the main tube 11.

[0070] The axial hole formed in the main tube 11 is a longitudinal threaded hole H5 into which the threaded sections M4 of the steel bars 4L and 4R are screwed.

[0071] The outer peripheries of the left and right half bodies are formed with outer peripheral threads H6 and H7 which are concentric with the longitudinal threaded hole H5 and have a larger diameter than the longitudinal threaded hole H5, and the end external threads M6 and M7 are provided in the outer peripheral threads H6 and H7.

[0072] The end external threads M6 and M7 have a phase consistent with the phase of the internal thread F5 of the threaded hole H5, and have pitches P6 and P7 different from the pitch P4 of the threaded section M4 of the reinforcing bars 4L and 4R. The secondary cylinders 12 and 13 include: sleeve portions 8 and 9 having end internal threads F8 and F9 threadedly coupled to the end external threads M6 and M7, and nut portions 14 and 15 coaxial with the sleeve portions and integrally formed at one side end of the sleeve portions.

[0073] The nut portions 14 and 15 are provided with nut portion internal threads F14 and F15 which are threadedly engaged with the threaded sections M4 of the reinforcing bars 4L and 4R and which have phases that match the phases of the end internal threads F8 and F9 of the sleeve portions 8 and 9 .

[0074] Here, if (1) P8 = P 14 +2mm or P9 = P 15 +2mm, when the secondary cylinders 12 and 13 are separated from each other, at P 14 , P 15 If (2)P 14 =P8+2mm or P 15 =P9+2mm, when the sub-tubes 12 and 13 are brought close to each other, extrusion occurs at P8 and P9. 14 ≡P 15 , P6≡P7≡P8≡P9, so in addition to the conventional meshing part, extrusion sometimes occurs in a chain reaction in the meshing part with pitch difference.

[0075] As described above, the present invention relates to locking by using extrusion caused by strong contact of the thread tooth surface, not only Figure 1 The structure shown in the figure also makes the yin and yang of the threads of the main cylinder 11, the auxiliary cylinder 12, and 13 reversed. Fig.12 The illustrated design also enables the desired locking by pressing.

[0076] Its construction is shown below.

[0077] A coupler in which the ends of opposing steel bars 4L and 4R are inserted into the coupler to prevent the steel bars and the coupler from loosening and to tighten the steel bars for transmitting axial force to lengthen them.

[0078] The coupler 10A comprises a main tube 11A and two sub-tubes 12A and 13A which are symmetrical and threadedly connected to the inner holes of the left and right halves of the main tube.

[0079] The axial hole formed in the main tube 11A is a longitudinal threaded hole H5 into which the threaded section M4 of the steel bar is screwed.

[0080] In the inner holes of the left and right half bodies, end internal thread holes H6 and H7 are formed which are concentric with the longitudinal thread hole H5 and have a larger diameter than the longitudinal thread hole H5, and end internal threads F6 and F7 are provided in the end internal thread holes H6 and H7.

[0081] The end internal threads F6 and F7 have a phase consistent with the phase of the internal threads F5 of the through threaded hole H5, and have pitches P6 and P7 different from the pitch P4 of the threaded section M4 of the reinforcing bars 4L and 4R. The secondary cylinders 12A and 13A include: sleeve portions 8A and 9A having end external threads M8 and M9 threadedly coupled to the end internal threads F6 and F7, and nut portions 14A and 15A coaxial with the sleeve portions and integrally formed at one side end of the sleeve portions.

[0082] The nut portions 14A and 15A are provided with nut portion internal threads F14 and F15 which are threadedly engaged with the thread segments M4 of the reinforcing bars 4L and 4R and have phases that coincide with the phases of the end external threads M8 and M9.

[0083] Here, if (1) P8 = P 14 +2mm or P9 = P 15 +2mm, when the sub-tubes 12A and 13A are separated from each other, at P 14 , P 15 If (2)P 14 =P8+2mm or P 15 =P9+2mm, when the sub-tubes 12A and 13A are brought close to each other, compression occurs at P8 and P9. 14 ≡P 15, P6≡P7≡P8≡P9, so in addition to the conventional meshing part, extrusion occurs in the meshing part with pitch difference.

[0084] The following can be understood from the above description. The connected steel bars can all be joined by products of equivalent composition and tightened by the same method of torque load operation. If the steel bar has a thread section within the forming tolerance, uniform tightening of the steel bar can be achieved even if there is a deviation in the pitch of the thread section. Since there is a difference in pitch between the peripheral threads (or end internal threads) on the outer periphery of the left half body and the outer periphery of the right half body of the main tube and the thread section of the steel bar, the increase in the surface contact pressure of the thread increases the friction force acting on the surface of the thread. When the surface of the thread teeth becomes rough due to compression, subsequent screw advancement and retreat are prevented, and extrusion occurs in the meshing section with a pitch difference in addition to the conventional meshing section.

[0085] Since peripheral threads (or end internal threads) with a pitch larger than the pitch of the threaded section of the steel bar, or peripheral threads (or end internal threads) with a pitch smaller than that of the threaded section of the steel bar are formed on the outer periphery of the left half body and the outer periphery of the right half body of the main tube, the difference in pitch makes it possible to specifically obtain threads with a larger friction force acting on the surface of the thread through the surface contact pressure of the thread, and also makes it easier to select the material of the main tube.

[0086] When a reaction force acting surface is formed on the outer surface of the through-threaded hole at the center portion in the longitudinal direction of the main cylinder, the reaction force receiving operation when a desired torque is applied to the polygonal nut portion becomes easy.

[0087] When a slit extending in the axial direction is formed in the through threaded hole in the middle of the main cylinder in the longitudinal direction, the front end position of the inserted reinforcing bar can be confirmed. When a slit of the same shape is also formed at a position opposite to the slit, it can be seen through, making it easier to confirm the front end position of the inserted reinforcing bar.

[0088] Although it is described that the through threaded hole is usually right-hand threaded in both the left and right half-barrels, when the reinforcing bar is left-hand threaded, surface roughness can be generated by the operation of rotating the sub-tubes counter-rotating each other to bring the sub-tubes closer together.

[0089] In addition, when a bending portion is provided at the anti-coupler side end of the steel bar, the steel bar can also have an anchoring function. Although the anchoring position is planned in advance, it has the advantage of being able to respond quickly when changes are needed. In addition, it should be supplemented that in the present invention, there is no intention to exclude the use of grouting (mortar, adhesive, thread locking agent, etc.). That is, in the structure of the present invention, it is not that grouting, etc. must not be introduced, but in principle, there are many cases where grouting does not need to be injected. Needless to say, grouting can be used together for locking in a known manner. In addition, even in a structure with a main tube and a secondary tube that reverses the yin and yang of the main tube and the secondary tube, the desired locking by extrusion can be achieved.

[0090] Reference numerals

[0091] 4, 4L, 4R: threaded steel bar, M4: threaded section, 4Le: front end of threaded steel bar, 6, 7: outer thread, H6, H7: end internal thread hole, F6, F7; end internal thread, M6, M7: end external thread, 10, 10A: coupler, 11, 11A: main tube, 11C: central body (reaction surface), 12, 12A, 13, 13A: auxiliary tube, H5: longitudinal thread hole, F5: internal thread, 8, 8A, 9, 9A: sleeve part, F8, F9: sleeve inner thread, M8, M9: sleeve External thread of the barrel, 14, 14A, 15, 15A: nut part, F14, F15: internal thread of the nut part, 17, 18: slit, 19: gauge, 21, 22: arrows in the diverging direction, 23, 24: arrows in the approaching direction, 25: bending part, P4: pitch of the thread section in the minimum tolerance formed product, P6, P7: pitch of the external (or internal) thread at the end, E: butt joint space of the steel bar end, Q: starting point of the thread combination (helix) in the secondary barrel, U: a certain angle reference point of the specified point Q, θ: rotation angle at the start time of meshing.

Claims

1. A coupler for threaded steel bar, wherein the coupler prevents the steel bar and the coupler from loosening in the coupler into which the ends of the opposing steel bars are inserted, and tightens the steel bar for lengthening the steel bar for transmitting axial force, wherein the coupler for threaded steel bar is characterized in that: The coupler comprises a main tube and two auxiliary tubes which are symmetrical and threadedly connected to the outer periphery of the left and right halves of the main tube. The axial hole formed in the main tube is a longitudinal threaded hole into which the threaded section of the steel bar is screwed. On the outer periphery of the left and right half bodies, an outer peripheral thread which is concentric with the longitudinal threaded hole and has a larger diameter than the longitudinal threaded hole is formed, and an end external thread is provided in the outer peripheral thread. The end external thread has a phase consistent with the phase of the internal thread of the longitudinal threaded hole and has a pitch different from the pitch of the thread section of the steel bar, The secondary cylinder comprises: A sleeve portion having an end internal thread threadedly engaged with the end external thread, and a nut portion coaxial with the sleeve portion and integrally formed at one end of the sleeve portion, The nut portion has a nut portion internal thread formed therein. The threaded section of the reinforcing bar is threadedly engaged with the nut portion internal thread, and the nut portion internal thread has a phase that matches a phase of the end internal thread.

2. The coupler for threaded steel bar according to claim 1, characterized in that: An outer peripheral thread having a pitch larger than the pitch of the threaded section of the steel bar is formed on the outer periphery of the left half body and the outer periphery of the right half body of the main tube.

3. The coupler for threaded steel bar according to claim 1, characterized in that: An outer peripheral thread having a pitch smaller than that of the threaded section of the steel bar is formed on the outer periphery of the left half body and the outer periphery of the right half body of the main tube.

4. A coupler for threaded steel bar, wherein the coupler prevents the steel bar and the coupler from loosening in the coupler into which the ends of the opposing steel bars are inserted, and tightens the steel bar for lengthening the steel bar for transmitting axial force, wherein the coupler for threaded steel bar is characterized in that: The coupler has a main tube and two auxiliary tubes that are symmetrical and threadedly connected to the inner holes of the left and right halves of the main tube. The axial hole formed in the main tube is a longitudinal threaded hole into which the threaded section of the steel bar is screwed. An end internal threaded hole which is concentric with the longitudinal threaded hole and has a larger diameter than the longitudinal threaded hole is formed in the inner holes of the left and right half bodies, and an end internal thread is provided in the end internal threaded hole. The end internal thread has a phase that matches the phase of the internal thread of the through threaded hole and has a pitch that is different from the pitch of the threaded section of the steel bar. The secondary cylinder comprises: A sleeve portion having an end male thread threadedly coupled to an end female thread, and a nut portion coaxial with the sleeve portion and integrally formed at one end of the sleeve portion, The nut portion is formed with a nut portion internal thread into which the threaded section of the reinforcing bar is threadedly engaged and which has a phase that matches a phase of the end external thread.

5. The coupler for threaded steel bar according to claim 4, characterized in that: End internal threaded holes with a thread pitch larger than the thread pitch of the threaded section of the steel bar are formed in the inner holes of the left half body and the right half body of the main tube.

6. The coupler for threaded steel bar according to claim 4, characterized in that: End internal threaded holes with a thread pitch smaller than the thread pitch of the threaded section of the steel bar are formed in the inner holes of the left half body and the right half body of the main tube.

7. The coupler for threaded steel bar according to claim 1 or 4, characterized in that: A reaction force acting surface when a desired torque is applied to the nut portion is formed on an outer surface of a center body which is a center portion in the longitudinal direction of the main cylinder.

8. The coupler for threaded steel bar according to claim 1 or 4, characterized in that: A slit extending in the axial direction is formed in the center body which is the middle part in the longitudinal direction of the main tube so as to allow viewing in order to confirm the position of the front end of the inserted reinforcing bar.

9. The coupler for threaded steel bar according to claim 8, characterized in that: A slit of the same shape is also formed in the main tube at a position facing the slit.

10. The coupler for threaded steel bar according to claim 1 or 4, characterized in that: The reinforcing bar has a bent portion functioning as an anchor plate at an end portion on the opposite side of the coupler.

11. A threaded steel bar, characterized in that: A coupler for a threaded steel bar according to any one of claims 1 to 10 is provided.

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