JP2016176229A - Reinforcement joint, and steel bar and sleeve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reinforcement joint enabling a joint operation to be easily carried out while keeping strength of a steel bar and a connection part, and the steel bar and a sleeve used for the same.SOLUTION: A reinforcement joint connects steel bars by disposing a sleeve 3 at both ends of steel bars 1, 2 to be connected. The steel bars have enlarged diameter parts 11, 12, which are sufficiently enlarged so as to have a cross sectional area that is more than 1.5 times larger than nominal cross sectional area of the steel bars, at ends. Male screws 12, 22, which have effective cross sectional area that is 1.5 times or more larger than the nominal cross sectional area of the steel bar or/and screw area per pitch of 20% or higher of the nominal cross sectional area of the steel bar, are engraved at the enlarged diameter part. The sleeve is formed into a cylindrical shape. A female screw 31 that is screwed with the male screw is engraved at an inner diameter part of the sleeve. The sleeve has length that allows the male screw engraved at the enlarged diameter part of both steel bars to be screwed in 10 pitches or more from both ends.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a structure for connecting reinforcing bars in an extending direction, and a reinforcing bar and a sleeve used in the reinforcing bar joint.

  Conventionally, as a reinforcing bar joint in which a sleeve is interposed, there is one in which a male screw is engraved on the reinforcing bar (see Patent Document 1). However, when a male screw is directly engraved at the tip of the reinforcing bar, it has been expected that the effective diameter of the reinforcing bar at the tip is reduced, which may cause a reduction in the strength of the reinforcing bar. Therefore, in order to maintain the strength of the reinforcing bar, assuming the engraving of the male screw, use a reinforcing bar with a diameter larger than the original reinforcing bar diameter, and the valley diameter of the male screw to be engraved is the diameter of the main bar It was not preferable from the economical point of view.

  Therefore, recently, there has been proposed a method in which a diameter-enlarged portion is formed at the end of a reinforcing bar and a male screw is engraved on the diameter-enlarged portion (see Patent Document 2). In this technique, a male screw having a thread number of 6 to 9 is engraved in the enlarged diameter portion, and the valley diameter of the engraved male screw is 1.05 to 1.50 times the rebar diameter. It was.

JP 2011-190589 A Utility Model Registration No. 3160121

  However, in the joint disclosed in Patent Document 2 described above, the thread (number of pitches) of the male screw engraved on the reinforcing bar is in the range of 6 to 9, so that it is screwed to the sleeve to the maximum extent. Even so, the number was nine. The strength of the joint portion depends on the total area of the thread, but when the thread (number of pitches) of the male thread is less than 9, the strength further increases. It would be a drop. Therefore, even if the male screw is simply screwed into the sleeve, the strength of the reinforcing bars and the strength of the connecting portion cannot be ensured.

  Furthermore, in the prior art described above, it is not clear whether or not the axes of the reinforcing bars to be connected coincide with each other, and the axial deviation must be corrected when screwed into the sleeve. The joint operation at the work site was more complicated than expected.

  The present invention has been made in view of the above-described points, and the object of the present invention is to provide a reinforcing bar joint that can be easily joined while maintaining the strength of the reinforcing bar and the strength of the connecting portion, and therefore Is to provide rebars and sleeves.

  Therefore, the present invention relating to a reinforcing bar joint is a reinforcing bar joint that connects both reinforcing bars with sleeves interposed at both ends of the reinforcing bars to be connected, both of the reinforcing bars being at the tip relative to the nominal cross-sectional area of the reinforcing bar. It has a diameter-expanded portion sufficiently expanded to have a cross-sectional area exceeding 1.5 times, and the effective cross-sectional area is 1.5 times or more the nominal cross-sectional area of the reinforcing bar, and / or per pitch A male screw having a screw area of 20% or more of the nominal cross-sectional area of the reinforcing bar is engraved in the enlarged diameter portion, the sleeve is formed in a cylindrical shape, and the inner diameter portion is provided with the male screw. An internal thread to be screwed is engraved, and the external thread engraved in the enlarged diameter portion of both the reinforcing bars from both ends has a length that can be screwed into 10 pitches or more.

  According to the above configuration, first, the enlarged diameter portion has a cross-sectional area exceeding 1.5 times the nominal cross-sectional area of the reinforcing bar, and the male screw when the male screw is engraved on the enlarged diameter portion. Since the effective cross-sectional area of the screw is configured to be 1.5 times or more, the cross-sectional area in the entire region of the part (screw part) acting on the joint becomes larger than the rebar diameter, The strength can be sufficiently maintained. Secondly, since the male screw of the enlarged diameter portion and the female screw of the sleeve are screwed together at 10 pitches or more, the load acting on the joint can be dispersed in the thread pitch of 10 pitches or more. At this time, if the screw area per pitch is 20% or more of the nominal cross-sectional area of the reinforcing bar, the total area by the 10 pitch is doubled, and the load acting on the joint can be withstood.

  Here, the “nominal cross-sectional area” of a reinforcing bar means the cross-sectional area indicated for a reinforcing bar that is not a uniform round bar, such as a deformed reinforcing bar, and is different from the actual cross-sectional area, but the actual cross-sectional area is nominal. It is larger than the cross-sectional area. In addition, the “effective cross-sectional area” is a cross-sectional area calculated in consideration of the crest and trough of the screw formed by engraving the male screw, and is calculated based on the effective diameter of the screw part. It is.

  In the invention having the above-described configuration, the sleeve is made of carbon steel, and the female screw engraved on the sleeve and the male screw engraved on the enlarged diameter portion are both constituted by metric screws. can do.

  When the sleeve is made of carbon steel, it can be manufactured at low cost, and it is easy to calculate the tensile strength, compressive strength, shear strength, etc., and a sleeve having a desired strength can be obtained. Further, since a male screw and a female screw are engraved with a metric screw, it is possible to perform processing by a general-purpose processing machine. In this case, the metric screw can be constituted by a crest diameter and a trough diameter as specified in JIS, and the effective diameter can be formed in a state in conformity with the standard. In addition, since the metric screw is determined by the outer diameter (screw thread diameter) of the enlarged diameter portion, when the cross-sectional area of the enlarged diameter portion is determined as described above, the outer diameter of the enlarged diameter portion is also Since it is inevitably determined, if the nominal cross-sectional area of the reinforcing bar is determined, the male screw to be engraved is also determined. In addition, since the screw area per pitch is specified in accordance with the standard, the strength of the screw portion (screwed portion) by screwing of 10 pitches or more can be assumed.

  Furthermore, in the invention of each configuration described above, at least one of the sleeves may be configured to be pressure-bonded by a lock nut that is screwed into a male screw of the enlarged diameter portion.

  In the case of such a configuration, it is possible to prevent the sleeve from rotating and being loosened by the press-fitting by the lock nut. “Press-bonding” means not a state where both members are fixed, but a state where they are in contact with each other in a strongly pressed state. Since both are screwed into the same male screw, a pressing force can be applied by screwing of the lock nut.

  In the case of the above configuration, the lock nut is further provided with a female screw that is screwed into the male screw of the enlarged diameter portion at at least 4 pitches, and the enlarged diameter portion is screwed with the sleeve and You may comprise so that the external thread for screwing of the said lock nut may be continuously engraved.

  According to the above configuration, since the lock nut is screwed into the male screw of the enlarged diameter portion at a pitch of 4 pitches or more, sufficient strength can be provided against the load acting on the lock nut. In particular, the lock nut is abutted (crimped) on the sleeve, but is basically an individual member, and can therefore be arranged in the enlarged diameter portion of the reinforcing bar in a state independent of the sleeve.

  The diameter-enlarged portion in each invention of the above-described configuration is the one that is expanded by compressing in the axial direction after heating the tip of the reinforcing bar, the one that is expanded by heading, or the diameter-enlarged portion at the tip of the reinforcing bar It can be constituted by any one formed by pressure contact.

  In the case where the enlarged diameter portion is formed by any of the above, the enlarged diameter portion can be configured by using the reinforcing bar material as it is by hot working or cold working, and a pressure welding technique widely used as a reinforcing bar connecting method. The diameter-enlarged portion formed of a desired material using can be configured at the tip of the reinforcing bar. When the enlarged diameter portion is provided at the tip of the reinforcing bar by pressure welding, a male screw may be formed in advance on the enlarged diameter portion, or the male screw may be engraved after the pressure welding. For the pressure welding, a conventional method for connecting reinforcing bars such as friction welding or gas pressure welding can be used. Note that these pressure welding and male thread processing are performed in advance in the factory, so that the rebar can be connected only by an easy connection method by screwing the sleeve in the field.

  Furthermore, the male screw of the said enlarged diameter part in the said structure equips the center of the end surface of this enlarged diameter part with a recessed part, and a positioning member may be arrange | positioned in the said recessed part.

  In the case of the above configuration, when the ends of the reinforcing bars to be connected are arranged in a predetermined state, the end surfaces of the enlarged diameter portions formed at the ends of both the reinforcing bars are opposed to each other, and the positions of the recesses on the end surfaces are aligned. Thereby, the axial center of both reinforcing bars can be made to correspond. Therefore, by disposing the positioning member in the concave portion, the reinforcing bars can be arranged in a state where the concave portions of both the enlarged diameter portions are combined. Here, the positioning member may be any member as long as it can be simultaneously engaged with the concave portions disposed to face each other. For example, the positioning member may have a shape obtained by combining two conical shapes on the bottom surface in addition to a spherical shape. In addition, the positioning member may be configured to be sized so as to be buried by two opposing concave portions, and is sized so that a gap is formed on both end surfaces of the enlarged diameter portions by partially engaging the concave portions. It may be configured. In addition, the recessed part for centering formed in lathe cutting may be used, and you may form it by a punch etc. separately. The positioning member may be fixed to the single edge side of the enlarged diameter portion of one of the reinforcing bars, but an individual member separated from the end surface may be used.

  The present invention relating to a reinforcing bar is used in any of the above-described reinforcing bar joints, and includes a diameter-enlarged portion having a cross-sectional area exceeding 1.5 times the nominal cross-sectional area of the reinforcing bar, and this expansion. A male threaded portion in which a male thread of 10 pitches or more having an effective sectional area of 1.5 times or more the nominal sectional area of the reinforcing bar is engraved on the outer peripheral part of the diameter part; It is a feature.

  According to the reinforcing bar having the above configuration, since the male screw is engraved on the enlarged diameter portion having a cross-sectional area sufficiently larger than the nominal cross-sectional area of the reinforcing bar, the influence of the strength reduction due to the formation of the male screw is eliminated. Can do. Moreover, since the external thread engraved in the enlarged diameter part is 10 pitches or more, when screwing with the sleeve, it can be screwed by 10 pitches or more. Furthermore, when a lock nut is used, the number of pitches of male threads is 10 pitches plus a range in which the lock nut can be screwed. Even in such a relatively long diameter-expanded portion and male screw portion, the effective cross-sectional area of the male screw is 1.5 times or more than the nominal cross-sectional area of the reinforcing bar, so that sufficient strength against bending load is provided. It will be.

  Further, the present invention relating to a reinforcing bar is a reinforcing bar used for a reinforcing bar joint in which the positioning member is disposed, and has a cross-sectional area exceeding 1.5 times the nominal sectional area of the reinforcing bar. A center screw, a male screw part having a male thread of 10 pitch or more engraved on the outer peripheral part of the enlarged diameter part by cutting with a lathe, and a centering used at the center of the end face of the enlarged diameter part during the lathe cutting process And a concave portion.

  According to such a configuration, when the male screw is formed by lathe cutting on the outer peripheral portion of the sufficiently enlarged diameter portion, the centering recess that is inevitably formed is disposed on the positioning member. Can be used for.

  On the other hand, the present invention relating to a sleeve is used for the reinforcing bar joint of each of the above-described configurations, and has a cylindrical sleeve body having a length that allows the male screw to be screwed in at least 10 pitches from both ends, and the sleeve body. And an internal thread portion engraved on the inner diameter portion.

  According to the sleeve having the above-described configuration, both ends of the two reinforcing bars to be connected can be screwed in at least 10 pitches from both sides, and both ends of the reinforcing bars can be connected sufficiently firmly. The female screw is engraved in a continuous state on the entire inner diameter portion. Since the male screw is screwed into 10 pitches or more, the total number of pitches of the female screw is 20 or more.

  According to the present invention relating to a reinforcing bar joint, the joint work can be easily performed while maintaining the strength of the reinforcing bar and the strength of the connecting portion. Further, according to the present invention relating to a reinforcing bar, a structure that can be used for the above joint can be realized, and according to the present invention relating to a sleeve, it can be interposed in the reinforcing bar.

It is explanatory drawing which shows embodiment of this invention which concerns on a reinforcing bar joint. It is explanatory drawing which shows the formation method of the enlarged diameter part of a reinforcing bar, and an external thread. It is explanatory drawing which shows the formation method of the enlarged diameter part of a reinforcing bar, and an external thread. It is explanatory drawing which shows the state of the connection by embodiment which concerns on a reinforcing bar joint. It is explanatory drawing which shows the connection state of other embodiment of this invention which concerns on a reinforcing bar joint. It is explanatory drawing which shows the usage method of a reinforcing bar joint. It is explanatory drawing which shows the usage method of a reinforcing bar joint. It is explanatory drawing which shows the form of the reinforcing bar used for a reinforcing bar joint.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating an exemplary embodiment of the present invention. As shown in this figure, in the reinforcing bar joint of this embodiment, enlarged diameter portions 11 and 21 are formed at the tips of two reinforcing bars 1 and 2 to be connected, and male screws 12 and 22 are engraved on the surface thereof. And a sleeve 3.

  The male screws 12 and 22 engraved in the enlarged diameter portions 11 and 21 have an enlarged sectional area 11 and 21 so that the effective sectional area is 1.5 times or more the nominal sectional area of the reinforcing bars 1 and 2. The cross-sectional area is expanded in advance so as to exceed 1.5 times the nominal cross-sectional area of the reinforcing bars 1 and 2. As will be described later in detail, the diameter expansion processing is to bulge the ends of the reinforcing bars 1 and 2 or to join members having a large diameter by pressure welding or the like.

  In addition, the male threads 12 and 22 to be engraved can be based on the screw area per pitch in addition to the effective sectional area. That is, the screw area per pitch (the area of the part where the thread is formed) is set to be 20% or more of the nominal cross-sectional area of the reinforcing bars 1 and 2. In the case of such a configuration, the total screw area corresponding to 10 pitches is more than twice the nominal cross-sectional area of the reinforcing bars 1 and 2, and the load acting on the screw thread is distributed over the screw area more than twice. By doing so, the strength can be maintained. When the male screws 12, 22 are JIS standard metric screws or the like, there is regularity between the effective cross-sectional area and the screw area, so the male screws 12, 22 are provided based on either one. However, when engraving male screws 12 and 22 that are out of specification, both conditions are preferably satisfied.

  The sleeve 3 is formed in a cylindrical shape (cylindrical in the figure), and in order to allow the male screws 12 and 22 engraved in the above-mentioned enlarged diameter portions 11 and 12 to be screwed in, the sleeve 3 is formed in the entire area of the inner diameter portion. Screws 31 are engraved. The cylindrical outer diameter is 1.3 times or more the valley diameter of the female screw. Thus, by making the outer diameter 1.3 times or more of the valley diameter, the cross-sectional area can be increased and the load acting on the reinforcing bars 1 and 2 can be withstood. Further, in order to allow the male screws 12 and 22 to be screwed in at least 10 pitches from both sides, the length of the sleeve 3 is set to be equal to or more than 10 pitches of the male screws 12 and 22. For example, in the case where the male screw is forwardly inclined M20, 20 mm (total 40 mm) is required as a range that can be screwed from both sides. Furthermore, in order to make it more, it can be set to 60 mm, for example. In this case, if it is assumed that the male screws 12 and 22 are screwed in by an amount corresponding to 12 pitches, a range of 48 mm is used. The tips of the male screws 12 and 22 do not reach the center. In this case, the vicinity of the center of the sleeve 3 is in a hollow state. Even if such a hollow state is formed, the strength of the sleeve 3 is not reduced by having a sufficient thickness (cross-sectional area).

  In addition, as a material for comprising the sleeve 3, the same cast steel as the reinforcing bars 1 and 2 may be used, but carbon steel can be used. Carbon steel is an alloy containing carbon in iron, but various characteristics can be obtained when the carbon content is in the range of 0.02% to 0.2%. Since carbon steel such as S45C having a carbon content of 0.45% is versatile and has a stable strength, an inexpensive sleeve 3 can be manufactured by using these.

  By the way, the reinforcing bar joint of this embodiment is configured to include lock nuts 4 and 5. The lock nuts 4 and 5 are internally threaded with female screws 41 and 51 so as to be screwed into the male screws 12 and 22 carved in the enlarged diameter portions 11 and 12 of the reinforcing bars 1 and 2. The lock nuts 4, 5 are in a state where the male screws 12, 22 of the reinforcing bars 1, 2 are screwed into the sleeve 3 (in a screwed state of 10 pitches or more), and further toward the both end faces 30 a, 30 b of the sleeve 3. To be screwed. Due to the screwing of the lock nuts 4, 5, the lock nuts 4, 5 are brought into strong contact with the both end faces 30 a, 30 b of the sleeve 3 and are brought into a crimped state. This state is shown in FIG.

  As shown in FIG. 2, when the lock nuts 4 and 5 are screwed together with the male screws 12 and 22, the sleeve 3 is firmly attached to the enlarged diameter portion 11 (tips of the reinforcing bars 1 and 2). It is connected (fixed) to the state. In other words, it is possible to prevent the screwed state of the male screw having a pitch of 10 pitches or more from changing due to the rotation of the sleeve 3. At the same time, a pressing force acts on the male screws 12 and 22, so that the looseness between the screws (backlash or the like) is eliminated, and the amount of displacement in the pulling direction can be reduced.

  In particular, when used when constructing a reinforced concrete structure, the load in the compression direction on the reinforcing bar is small, and the tensile load is exclusively important. Therefore, strong joint strength can be obtained by eliminating the looseness (backlash or the like) of the screw in the pulling direction by the lock nuts 4 and 5.

  Since the lock nuts 4 and 5 are used for the purpose as described above, they do not need to be long like the sleeve 3 and may have a screwing range of about 4 pitches at most. The term “4 pitches or more” means that it is a sufficient level in consideration of the collapse of the screw thread in order to maintain the crimped state, and in reality, a pitch of about 3.5 is sufficient.

  In order to configure the joint having the above-described configuration, the reinforcing bars 1 and 2 are provided with the enlarged diameter portions 11 and 12 and the male screw portion in which the male screws 12 and 22 are engraved on the outer peripheral surface thereof. In addition, the sleeve 3 is provided with a female screw portion in which a female screw 31 is formed on the inner diameter portion. In the following description, the portions where the male screws 12 and 22 are engraved may be referred to as male screw portions 12 and 22, and the portion where the female screw 31 is engraved may be referred to as female screw portion 31.

  Here, the diameter expansion process will be described. In the diameter expansion processing, there are a case where the tips of the reinforcing bars 1 and 2 are directly processed to increase the diameter and a case where a large diameter member is joined. As a method of directly processing the ends of the reinforcing bars 1 and 2, for example, there is a process of bulging a part of the reinforcing bars 1 and 2 by pressing the ends of the reinforcing bars 1 and 2 in the axial direction. This state is shown in FIG. Since both the reinforcing bars 1 and 2 are the same processing, only one reinforcing bar 1 is illustrated.

  As shown in FIG. 3 (a), the tip portion 10 is bulged by pressing the tip portion 10 in a predetermined range in the axial direction with respect to what was originally the same type of reinforcing bar material up to the tip. is there. In order to bulge the reinforcing bar material, there is one that deforms the heated tip by applying a strong pressing force to the heated tip. For example, as used in a method for manufacturing a fixing reinforcing bar developed by the present inventors (see Japanese Patent Application Laid-Open No. 2008-334206), it is heated by a high frequency induction heater and then expanded by being compressed in the axial direction. There is a way. In addition, there is a method of bulging to a predetermined diameter and a predetermined shape by cold forging, such as heading.

  FIG.3 (b) has shown the state which expanded the diameter of the reinforcing bar material by the above. As shown in this figure, the tip portion 10 of the reinforcing bar material is pressed and shrunk, but the portion bulges out to the periphery and an enlarged diameter portion 11 having an enlarged outer diameter is formed. Since the drawing is schematically drawn, the enlarged diameter portion 11 is shown as a round bar, but in reality, the surface may be distorted.

  By cutting the surface of the enlarged diameter portion 11 formed in this way and further threading, the enlarged diameter portion 11 having the male screw 12 as shown in FIG. 3C can be provided. . Therefore, the enlarged diameter portion 11 before threading has a diameter larger than the thread diameter of the male screw 12 in order to provide the male screw 12 having a predetermined effective cross-sectional area.

  On the other hand, it is also possible to form the enlarged diameter portions 11 and 21 at the tips of the reinforcing bars 1 and 2 by joining those manufactured by a material different from the reinforcing bars 1 and 2 by pressure welding or the like. The state of this type of diameter expansion processing is shown in FIG. When the enlarged diameter portion 11 is joined to the tip of the reinforcing bar 1 by pressure welding or the like, and the enlarged diameter portion 11 is first joined to form the male screw 12 in the enlarged diameter portion 11 (FIGS. 4A and 4B). And a case where the enlarged diameter portion 11 in which the male screw 12 is engraved is joined to the tip of the reinforcing bar 1 (see FIGS. 4C and 4D).

  When engraving the male screw 12 later, as shown in FIG. 4A, an end surface 11 b of a small diameter portion 11 a for pressure contact is formed at one end of the enlarged diameter portion 11, and this end surface 11 b is formed on the reinforcing bar 1. It is brought into contact with the end surface 10b of the tip 10a, and friction welding or gas pressure welding is performed. And as shown in FIG.4 (b), although it will be in the state which a part of material protruded as the burr | flash 11c in the peripheral part press-contacted, since it is a smaller diameter than the main body of the enlarged diameter part 11, The engraving of the male screw 12 is not hindered. The state in which the male screw 12 is engraved is the same as in FIG.

  On the other hand, in the case where the enlarged diameter portion 11 having the male screw 12 previously engraved is joined by pressure welding, as shown in FIG. 4C, the enlarged diameter portion 11 having the male screw 12 engraved on the surface, The member provided with the small diameter part 11a for the press contact provided in the end is provided, and this small diameter part 11a is press-contacted to the reinforcing bar 1 similarly to the above.

  Thus, when joining by pressure welding, if it is the method of press-contacting the enlarged diameter part 11 which has the external thread 12 to the front-end | tip of the reinforcing bar 1, there will be no effort of engraving the external thread 12 at the front-end | tip of the long reinforcing bar 1. Therefore, although processing becomes easy, care must be taken so that the center of the enlarged diameter portion 11 (male screw 12) coincides with the axis of the reinforcing bar 1. On the other hand, when the male screw 12 is engraved after the diameter-enlarged portion 11 is first joined, if the male screw 12 is engraved while rotating around the axis of the rebar 1, the axis of the rebar 1 And deviation from the central axis of the male screw 12 can be prevented. Since both have advantages and disadvantages, any method may be selected.

  By the way, as described above, the male screws 12 and 22 engraved in the enlarged diameter portions 11 and 12 are metric screws according to the JIS standard, and the total number of pitches is 10 or more. In order to engrave the screw pitch number of 10 or more, the lengths of the enlarged diameter portions 11 and 12 are formed in advance so that the pitch number can be engraved. For example, in the M20 metric screw, the length of one pitch is 2 mm, so that the pitch becomes 20 mm at 10 pitches, and the length of the enlarged diameter portions 11 and 21 is set to 20 mm or more in order to engrave a male screw of 10 pitches or more. It is.

  When engraving male screws with a pitch of 10 pitches or more, since the lock nuts 4 and 5 described later cannot be screwed, the length of the enlarged diameter portions 11 and 12 is set to 50 mm, and the male screws are engraved with 50 pitches. can do. Since the cross-sectional area of the enlarged diameter portions 11 and 12 and the effective cross-sectional area of the engraved male screws 12 and 22 are 1.5 times or more the nominal sectional area of the reinforcing bars 1 and 2 as described above, the enlarged diameter portion Even if 11 and 21 are long, they are not inferior in strength. However, when the material is used economically, the lengths of the enlarged diameter portions 11 and 12 may be set short.

  Next, another embodiment according to the joint will be described. FIG. 5 exemplifies these embodiments, and the rebars 1 and 2 are shown in cross section in order to make it easier to grasp the relationship between the rebars 1 and 2 and the sleeve 3. FIG. 5A shows the representative embodiment.

  As shown in these drawings, the lock nuts 4 and 5 are not essential members. As shown in FIG. 5A, in a typical embodiment, when the male screws 12 and 22 are screwed into the sleeve 3 in a relatively short range of 10 pitches or more (the figure assumes 11 pitches) The leading ends are in a state having a gap C <b> 1 inside the sleeve 3. At this time, since the male screws 12 and 22 are also present on the outer sides of both ends of the sleeve 3, it is possible to obtain a range in which the lock nuts 4 and 5 can be screwed together.

  Unlike this, as shown in FIG. 5 (b), when the male screws 12, 22 are screwed deeply (the figure assumes 15 pitches), even if the sleeve 3 having the same length L1 is used, The gap C2 between the tips is narrower than in the above case, and on the other hand, there is no region where the lock nut is screwed to both ends of the sleeve 3. In such a screwed state with the sleeve 3, no tightening force is applied by the lock nut, but a large number of male screws 12 and 22 are screwed from both sides of the sleeve 3. The integrity of both the reinforcing bars 1 and 2 and the sleeve 3 can be ensured. In particular, as shown in the drawing, the rebars 1 and 2 are approached from both sides so that the gap C1 is reduced, so that a tensile force can be applied to the rebars 1 and 2 to thereby increase the fastening force. is there.

  FIG. 5C shows that the length L2 of the sleeve 3 is longer than the above in order to screw the male screws 12 and 22 in a long range of 10 pitches or more (the figure assumes 15 pitches) from the beginning. It is constructed in a scale. In this case, since it is assumed that the lock nut is not screwed, most ranges of the male screws 12 and 22 are screwed into the sleeve 3. The gap C1 at this time is set to be approximately the same as that in the representative embodiment (FIG. 5A). Even in such a screwed state, the male screws 12 and 22 are screwed into the sleeve 3 from both sides without using a lock nut, and the rebars 1 and 2 and the sleeve 3 are integrated. Can be secured. As described above, although it is not always necessary to tighten the lock nut, the labor for screwing the male screws 12 and 22 of the reinforcing bars 1 and 2 into the sleeve 3 and the labor for screwing the lock nuts 4 and 5 are not required. In view of comparison, it is preferable to use the lock nuts 4 and 5.

  Next, a method of using the joint having the above configuration will be briefly described. Here, only a representative one of the embodiments will be described. FIG. 6 shows the procedure. As shown in this figure, first, lock nuts 4 and 5 are inserted in advance into both the reinforcing bars 1 and 2 to be connected (see FIG. 6A). The lock nuts 4 and 5 can be inserted by screwing (reversing) the male screw portions 12 and 22. Next, the male threaded portion 12 of one of the reinforcing bars 1 is screwed into the female threaded portion 31 from one side of the sleeve 3 (see FIG. 6B). At this time, the rebar 1 or the sleeve 3 is rotated 10 times or more so that the pitch is 10 pitches or more. In order not to change the screwing state at this time, one lock nut 4 is screwed and brought into contact with one end face of the sleeve 3 (see FIG. 6C).

  Subsequently, the male screw portion 22 of the other rebar 2 is screwed into the female screw portion 31 from the opposite side of the sleeve 3 (see FIG. 6D). At this time, in order not to change the screwed state of the male screw portion 12 and the sleeve 3 that have been screwed together, the sleeve 3 is not rotated but the other reinforcing bar 2 is rotated. At this time, the number of rotations is 10 times or more, and screwing of 10 pitches or more is executed. Thereafter, the other lock nut 5 is screwed and brought into contact with the other end surface of the sleeve 3 (see FIG. 6E). After the other lock nut 5 has been screwed, both the lock nuts 4 and 5 are sufficiently tightened and brought into a crimped state.

  FIG. 7 shows another method of use. As shown in this figure, the sleeve 3 is inserted into one of the reinforcing bars 1 together with one of the lock nuts 4 (see FIG. 7A). In this state, the tip end surface of the other reinforcing bar 2 is brought into contact with the tip end surface of the reinforcing bar 1 (see FIG. 7B), and then the sleeve 3 is rotated to rotate the male screw portions 12 and 22 of both the reinforcing bars 1 and 2. The female screw portion 31 is screwed so as to straddle (see FIG. 7C). In this case, after the screwing of the other rebar 2 with the male screw portion 22 is started so that 10 pitches or more of the male screw portions 12 and 22 can be screwed together, the rotational speed of the sleeve 3 becomes 10 or more. Adjust it.

  Even in the above-described method of use, the lock nuts 4 and 5 are inserted into both the reinforcing bars 1 and 2 in advance, so that the lock nuts 4 and 5 are finally sufficiently screwed and crimped to both end faces of the sleeve 3. (See FIG. 7 (d)).

  Here, in order to smoothly perform the above-described usage, there may be the following modifications. That is, as shown in FIG. 8, the recesses 13 and 23 are formed in the center on the front end surfaces of the reinforcing bars 1 and 2, and the positioning member 6 that can be engaged with both the recesses 13 and 23 is installed. As the recesses 13 and 23, those for centering used when the male screws 12 and 22 are engraved in the enlarged diameter portions 11 and 21 can be used. This is because when the male screws 12 and 22 are engraved by cutting using a lathe or the like, the concave portions 13 and 23 for centering are formed.

  In addition, the positioning member 6 is illustrated as an elliptical sphere such as a rugby ball. However, the positioning member 6 may be a sphere or may be formed by joining two conical shapes at the bottom surface. Further, the positioning member 6 may be sized so as to divide into two recesses 13 and 23, but may be sized such that both ends are partially engaged and the central portion is not buried. This is determined by how the interval between the end faces of the reinforcing bars 1 and 2 to be connected is made.

  As described above, according to the present embodiment, the rebars 1 and 2 in which the male screws 12 and 22 are engraved on the enlarged diameter portions 11 and 12 having sufficient strength are connected via the sleeve 3 having sufficient thickness. Can be connected together. Further, as is apparent from the description of the usage method, the connecting work is easy. In the case of the configuration in which the reinforcing bars have the recesses 13 and 14 and the positioning member 6 is disposed, the rebars 1 and 2 are arranged with their axes aligned with each other, and the connection by the sleeve 3 is facilitated. can do.

  The above embodiments are illustrative of the present invention and are not intended to limit them. Therefore, various modifications are possible within the scope of the present invention. For example, the male screws 12 and 22 and the female screw 31 are metric screws, but the details thereof may be fine threads as well as coarse threads. Moreover, the form made into a trapezoid screw may be sufficient. Moreover, it is not limited to the screw in a domestic standard, You may use the inch screw of a unified screw or a Whitworth screw. What is necessary is just to comprise so that it may become the screw pitch or screw surface area along the reference | standard of this invention.

  Furthermore, it is also possible to use a multi-threaded screw such as a double thread or a triple thread for these various screw structures. By using a multi-threaded screw, when the male screws 12 and 22 of the reinforcing bars 1 and 2 and the female screw 31 of the sleeve 3 are screwed together, a predetermined range of screwing can be completed by a small number of rotations. That is, in the case of double thread, the lead length is twice the pitch length, and in the case of triple thread, the lead length is three times the pitch length. The screwing can be completed by rotating 1/2 or 1/3 of the single thread. This saves the labor of connecting the reinforcing bars at the construction site, and contributes to enabling the bar arrangement work in a short time.

  Below, the result of the tensile test of the actually created reinforcing bar joint is shown. As a typical example, several types of reinforcing bars are shown. The table below shows the dimensions and the sleeve used, such as the nominal cross-sectional area of the reinforcing bar and the effective cross-sectional area of the external thread. In each case, the test was conducted by screwing a 10 pitch male screw.

  As a result of the tensile test of the rebar joint shown above, all the results obtained have a strength exceeding the allowable range. In addition, as a reference example, the cross-sectional area of the enlarged diameter portion is 1.4 times the nominal cross-sectional area of the reinforcing bar and 10 pitches or more are screwed together, and the cross-sectional area is the same as the embodiment, but the screwing pitch As a result of conducting a tensile test in the case where the number was 9.5 or less, all were within the allowable range.

  Therefore, by inserting the male screw having the effective cross-sectional area into the sleeve by 10.5 pitches, it was possible to obtain a result that the connection state was sufficient while considering the safety factor.

DESCRIPTION OF SYMBOLS 1, 2 Rebar 3 Sleeve 4, 5 Lock nut 6 Positioning member 10 Rebar tip 10a Rebar tip 10b Rebar tip end face 11, 12 Expanded diameter part 11a Small diameter part 11b Small diameter part end face 11c Burr 12, 22 Male thread ( (Male thread)
13, 23 Recess 30a, 30b Sleeve end face 31 Female thread (Female thread part)
L1, L2 Sleeve length C1, C2 Gap between rebar tips

Claims (9)

A rebar joint that connects both rebars with sleeves at both ends of the rebars to be connected,
Each of the rebars has a diameter-expanded portion that is sufficiently enlarged to have a cross-sectional area that exceeds 1.5 times the nominal cross-sectional area of the rebar at the tip, and the effective cross-sectional area has a nominal area of the rebar. A male screw having a thread area of 1.5 times or more with respect to the cross-sectional area or / and a screw area per pitch of 20% or more of the nominal cross-sectional area of the reinforcing bar is engraved in the enlarged diameter portion,
The sleeve is formed in a cylindrical shape, and an inner thread is engraved with an internal thread that is screwed into the external thread. Reinforcing bar joint characterized by having a length that can be screwed in more than the pitch.   The rebar joint according to claim 1, wherein the sleeve is made of carbon steel, and both the internal thread engraved in the sleeve and the external thread engraved in the enlarged diameter portion are metric threads.   The reinforcing bar joint according to claim 1 or 2, wherein at least one of the sleeves is crimped by a lock nut that is screwed into a male screw of the enlarged diameter portion.   The lock nut is provided with a female screw that is screwed into the male screw of the enlarged diameter portion at at least 4 pitches, and the enlarged diameter portion is used for screwing with the sleeve and screwing of the lock nut. The rebar joint according to claim 3, wherein male threads are continuously engraved.   The diameter-expanded portion is a portion that is expanded by heating in the axial direction after heating the tip of the reinforcing bar, a portion that has been expanded by heading, or a portion in which the diameter-expanded portion is pressed against the tip of the reinforcing bar The reinforcing bar joint according to any one of claims 1 to 3.   5. The reinforcing bar joint according to claim 1, wherein the male screw of the diameter-expanded portion includes a recess at the center of the end surface of the diameter-expanded portion, and a positioning member is disposed in the recess. Reinforcing bars used for the reinforcing bar joint according to any one of claims 1 to 5,
An expanded diameter portion having a cross-sectional area exceeding 1.5 times the nominal cross-sectional area of the reinforcing bar, and an effective cross-sectional area of 1.5 times or more the nominal cross-sectional area of the reinforcing bar at the outer peripheral portion of the expanded diameter portion And a male screw part in which a male screw of 10 pitches or more having an effective cross-sectional area is engraved. Reinforcing bars used for the reinforcing bar joint according to claim 6,
A diameter-enlarged portion having a cross-sectional area exceeding 1.5 times the nominal cross-sectional area of the reinforcing bar, and a male screw in which a male screw having a pitch of 10 pitches or more is engraved on the outer peripheral portion of the diameter-enlarged portion by cutting with a lathe And a centering recess used at the time of the lathe cutting at the center of the end face of the enlarged diameter portion. A sleeve used for the reinforcing bar joint according to claim 1, wherein the male screw has a length capable of being screwed in at least 10 pitches from both ends, and is engraved on an inner diameter portion of the sleeve main body. And a female screw part.

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