JP2009174126A - Mechanical joint for reinforcement - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid a decrease in the shear strength, buckling strength, etc. of a reinforced concrete support etc. <P>SOLUTION: A connecting bolt 2 is provided with a central portion 21 with a predetermined axial length, so that a gap smaller than the outside diameter of a tubular member can be surely secured between the pair of tubular members 1. Thus, when a hoop 4 abuts on the tubular member 1, an increase in the winding diameter of the hoop can be suppressed by winding the hoop around the gap. This makes it unnecessary to decrease the winding diameter of the hoop 4 so as to secure the covering depth of concrete, and can prevent the decrease of the shear strength and buckling strength of the reinforced concrete support, a beam, etc. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mechanical joint of a main reinforcing bar arranged along the outer periphery of a concrete support or the like.

  Conventionally, as shown in FIG. 5, a plurality of main reinforcing bars 303 are arranged along the outer periphery of a reinforced concrete column or the like of a building with a predetermined interval therebetween. On the other hand, when this support | pillar etc. is long, the mechanical coupling (for example, refer patent documents 1-3) of the reinforcing bar for connecting main reinforcing bars is used. Further, in order to prevent shear fracture and buckling of the pillars and the like due to an earthquake or the like, the reinforcing bar 304 is wound around the main reinforcing bar 303 which has been arranged.

By the way, in reinforced concrete, in order to ensure the fire resistance and rust resistance of the reinforcing bars and the adhesion between the reinforcing bars and the concrete, a concrete layer of a predetermined thickness, so-called between the outer surface of the reinforcing bars and the surface of the reinforced concrete. It is necessary to ensure the “cover thickness”. This “cover thickness” is required to be 30 mm or more for a column or beam. Therefore, in a reinforced concrete support column or the like, it is necessary to reduce the outer diameter of the reinforcing bar 304, which is the maximum diameter of the reinforcing bar structure, from the outer diameter of the reinforced concrete by twice the “covering thickness”.
Japanese Patent Laid-Open No. 10-037384 (FIG. 1 etc.) Japanese Patent Laid-Open No. 11-256767 (FIG. 1 etc.) JP 2000-30763 A (FIG. 1 etc.)

  However, the inventor of the present application has found that there are the following points to be improved in the above-described mechanical joint of reinforcing steel bars. That is, when the arrangement interval of the reinforcing bars 304 is narrow, when the reinforcing bars are wound around the main reinforcing bar 303, the reinforcing bars may come into contact with the joint portion of the main reinforcing bar. However, since the outer diameter of the cylindrical member 301 constituting the mechanical joint of the reinforcing bar is larger than the outer diameter of the main reinforcing bar 303 connected via the cylindrical member, in such a case, the cylindrical member 301 is placed on the cylindrical member. The winding diameter of the wound strip 304 is larger than the winding diameter when the strap is wound directly around the main reinforcing bar by the difference in outer diameter between the tubular member and the main reinforcing bar.

  That is, as shown in FIG. 6, when winding the reinforcing bar 304 directly around the main reinforcing bar 303, the radius (r) of the outer periphery around which the reinforcing bar is wound is calculated from the radius of the outer surface 305 of the reinforced concrete as “covering”. The dimension is obtained by subtracting the thickness (t). However, when the band 304 comes into contact with the joint portion of the main reinforcing bar 303, that is, the tubular member 301, the radius of the outer periphery around which the band is wound increases by Δr, and conversely, “cover thickness” (t ) Is reduced by Δr. Therefore, in order to ensure the “cover thickness” (t), the radius (r) of the outer periphery around which the strap 304 is wound must be reduced by Δr for all the strips.

  By the way, the shear strength and buckling strength of the reinforced concrete support and the like increase as the cross-sectional area of the concrete surrounded by the band 304 increases. Therefore, it is required to make the radius (r) of the outer periphery around which the band 304 is wound as large as possible. However, as described above, when the strap 304 abuts on the tubular member 301, the radius (r) around which the strap is wound is small in order to secure the “cover thickness” (t). Therefore, the shear strength and buckling strength of reinforced concrete columns and the like are reduced.

  In the conventional mechanical joint shown in FIG. 6, when the axial distance L between the pair of left and right cylindrical members 301, 301 is sufficiently large, the stirrup 304 can be wound around the axial distance L. In such a case, an increase in the radius (r) of the outer periphery around which the band 304 is wound can be avoided. However, with regard to the method of winding the band 304 in the axial interval L as described above, the following problems may occur in the conventional mechanical joint.

  That is, in the conventional mechanical joint shown in FIG. 6, the connecting bolt 302 forms a male thread over the entire length, as shown in FIG. 7, whereby the axial distance L can be narrowed. That is, when connecting the main reinforcing bars 303, the axial interval L is narrow, and it is not assumed that the axial interval L is increased. In addition, since no positive means for securing the axial interval L is provided, when connecting the main reinforcing bars 303, in order to ensure the axial interval L to be equal to or longer than a predetermined length, a great deal of attention from the operator is required. Force, post-examination and correction are required. Therefore, in the conventional mechanical joint, it is not easy to ensure the axial distance L that is equal to or longer than a predetermined length. For this reason, when the axial interval L is narrow, it is difficult to sufficiently sandwich the band 304 within the axial interval L, and it is difficult to avoid an increase in the radius (r) around which the band is wound. It becomes.

  In the case of a mechanical joint that connects the main reinforcing bars 303 in a turnbuckle manner, as shown in FIG. 8, the connecting bolt 402 has a wrench-hanging nut portion 423 provided at the center, with the right side on both sides. Male screws 422 and 422 made up of screws and left-hand screws are formed. For this reason, the nut portion 423 having a large outer diameter becomes an obstacle, and the strap cannot be sufficiently sandwiched in the axial interval L, and it is difficult to avoid an increase in the radius (r) for winding the strap. Become

  SUMMARY OF THE INVENTION An object of the present invention is to provide a mechanical joint for a reinforced concrete that can avoid a decrease in shear strength, buckling strength, etc. while ensuring the concrete cover thickness of a reinforced concrete support or the like.

  In order to achieve the above object, a mechanical joint of a reinforcing bar according to the present invention is characterized by comprising a pair of cylindrical members and a connecting bolt for connecting the pair of cylindrical members to each other, and one end of the pair of cylindrical members. Internal threads are respectively screwed on the inner periphery of the part, and the connecting bolt has a central part having a predetermined axial length and male screw parts screwed at both ends sandwiching the central part. The female screw and the male screw can be screwed to each other, and the maximum diameter of the central portion of the connecting bolt is smaller than the outer diameter of the cylindrical member and larger than the minimum inner diameter of the female screw. It is in connecting the inner periphery of the other end part of the said cylindrical member to the outer periphery of the one end part of a reinforcing bar, respectively.

  According to another aspect of the present invention, there is provided a mechanical joint for reinforcing bars comprising a pair of cylindrical members and a connecting bolt for connecting the pair of cylindrical members to each other, and an inner periphery of one end of the pair of cylindrical members. Are respectively provided with female screws, and at least both ends of the connecting bolt are provided with male screws that can be screwed together with the female screw, and the axial length of the connecting bolt is: The other end of the cylindrical member is longer than the sum of the maximum lengths that can be inserted from one end of the cylindrical member while screwing the male screw threaded on both ends of the connecting bolt. The inner circumference is connected to the outer circumference of one end of the reinforcing bar.

  The female screw threaded on one of the pair of cylindrical members is a right-hand thread, the female thread threaded on the other is a left-hand thread, and one of the male thread parts threaded on both ends of the connecting bolt is a right-hand thread. And the other is a left-hand screw, and the female screw made of the right-hand screw and the male screw made of the right-hand screw can be screwed together, and the female screw made of the left-hand screw and the male screw made of the left-hand screw May be configured such that they can be screwed together.

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Here, the “cylindrical member” means a member having at least an end portion of a reinforcing bar or a hollow hole into which a “connection bolt” can be inserted, and corresponds to a metallic pipe such as iron, a cast product, or a forged product. . “The central part of the predetermined axial length” is not limited to the central part of the axial length equal to or greater than the diameter of the strap, but also the central part of the axial length less than the diameter of the strap. Including. “Minimum inner diameter of the female screw” means the inner diameter formed at the top of the thread of the female screw. “In use, the inner circumference of the other end of the cylindrical member is connected to the outer circumference of one end of the reinforcing bar” means that the other end of the cylindrical member is reduced in diameter and the inner circumference is connected to the reinforcing bar. Not only when crimping to the outer periphery of one end, but also when forming a female screw on the inner periphery of the other end of the cylindrical member and screwing a male screw formed on the outer periphery of one end of the rebar to the female screw Including.

  The effects of the mechanical joint of the reinforcing bar according to the present invention are as follows. That is, the connecting bolt is provided with a central portion having a predetermined axial length, and the maximum diameter of the central portion is smaller than the outer diameter of the cylindrical member and larger than the minimum inner diameter of the female screw screwed on the cylindrical member. Thus, a gap smaller than the outer diameter of the cylindrical member can be reliably ensured between the pair of cylindrical members. Therefore, when the strap is in contact with the tubular member, an increase in the winding diameter of the strap can be suppressed by winding the strap in the gap. For this reason, in order to ensure the cover thickness of concrete, it is not necessary to reduce the winding diameter of the band, and it is possible to prevent a decrease in shear strength and buckling strength of reinforced concrete columns and beams.

  Further, by making the axial length of the connecting bolt longer than the sum of the maximum lengths that can be inserted from one end of the tubular member while screwing the male screw screwed to both ends of the connecting bolt, A gap smaller than the outer diameter of the cylindrical member can be reliably ensured between the pair of cylindrical members. Thereby, the same operation effect as the above-mentioned operation effect can be obtained.

  The reinforcing bar mechanical joint according to the present invention will be described with reference to FIGS. As shown in FIG. 1, the mechanical joint of a reinforcing bar according to the present invention includes a pair of sleeves 1 and 1 made of an iron cylindrical member, and a connecting bolt 2 for connecting the pair of sleeves to each other. Female threads 11 and 11 are screwed on the inner periphery of one end of the pair of sleeves 1 and 1, respectively. One of the female threads 11 is a right-hand thread, and the other is a left-hand thread.

  As shown in FIG. 2, the connecting bolt 2 is a forged product of iron, and has a center portion 21 having a predetermined axial length and a right-hand screw and a left-hand screw threaded at both ends sandwiching the center portion. There are male screws 22 and 22 made of screws. The outer diameters of the male screws 22 and 22 are substantially the same as the outer diameter of the main reinforcing bars so as to be equal to the tensile strength of the main reinforcing bars 3 and 3 made of deformed reinforcing bars. The right-handed male screw 22 and the left-handed male screw 22 formed at both ends of the connecting bolt 2 are a right-handed female screw 11 formed on one of the pair of sleeves 1 and a left-handed female screw 11 formed on the other. In addition, each can be screwed. Further, as shown by an arrow AA in FIG. 2, the central portion 21 of the connecting bolt 2 has a columnar shape that is substantially the same as the outer diameter of the left and right male screws 11, 11. A notch 21a that can be hung is provided. The axial length of the central portion 21 is set larger than the outer diameter of the band 4.

  Next, a usage mode of the mechanical joint of the above-described reinforcing bar will be described with reference to FIG. First, the other ends of the pair of sleeves 1 and 1 are respectively inserted into one end portions of main reinforcing bars 3 and 3 made of deformed reinforcing bars, the outer periphery of the sleeves is pressed with a press or the like, and the inner periphery is reduced in diameter. Engage in bamboo shoots on the outer periphery of the reinforcing bar. Next, the front end portions of the male screw portions 22 and 22 formed at both ends of the connecting bolt 2 are screwed into the female screws 11 and 11 provided at one end portions of the pair of sleeves 1 and 1, respectively. A wrench or the like is hung on the notch portion 21a provided in the upper portion and the connecting bolt is rotated. When the connecting bolt 2 is rotated, the male screw portions 22 and 22 formed at both ends are in the opposite directions of the right screw and the left screw, so the male screw portions formed at both ends are the female screws of the left and right sleeves 1 and 1. 11 and 11, respectively, and the main reinforcing bars 3 and 3 on both sides are connected like a turnbuckle.

  The outer diameter of the central portion 21 of the connecting bolt 2 is substantially the same as the outer diameter of the male screws 22, 22 provided on both sides of the connecting bolt, and is therefore larger than the inner diameter of the female screw 11 of the sleeve 1. For this reason, the connecting bolt 2 cannot be screwed into the female screw 11 of the sleeve 1 beyond the central portion 21, and therefore, between the left and right sleeves 1, 1, the axial length of the central portion is longer than that. The gap is always secured. Therefore, when the band 3 is wound between the left and right sleeves 1, 1, the inner periphery of the band contacts the outer periphery of the central portion 21 of the connecting bolt 2.

  As described above, the outer diameter of the central portion 21 is substantially the same as the outer diameter of the male screws 22, 22 provided on both sides of the connecting bolt 2, and the outer diameter of the male screw is the outer diameter of the main reinforcing bars 3, 3. It is almost the same. Therefore, as shown in FIG. 1, the outer diameter of the reinforcing bar 4 wound between the left and right sleeves 1, 1 should be substantially the same as the outer diameter of the reinforcing bar wound directly around the outer periphery of the main reinforcing bar 3. Can do.

  Therefore, as compared with the case where the strips 304 are wound around the outer periphery of the sleeve 301 as in the conventional example shown in FIG. 6, the outer diameter of the strip 4 is the outer periphery of the strips wound directly around the outer periphery of the main reinforcing bar 3. It can avoid becoming larger than a diameter. As a result, it is not necessary to reduce the winding diameter of the reinforcing bar 4 wound directly around the main reinforcing bar 3, and it is possible to prevent a decrease in shear strength and buckling strength of reinforced concrete columns and beams.

  Next, another embodiment of the mechanical joint for reinforcing steel bars according to the present invention will be described with reference to FIG. In FIG. 3, parts and parts equivalent to those shown in FIG. 2 are numbered by adding 100 to the parts and parts shown in FIG. 2 for convenience of reference. In the rebar mechanical joint shown in FIG. 3, female threads 111 and 111 are threaded from the end surfaces to the axial lengths LS1 and LS2 on the inner circumference of one end of the pair of sleeves 101 and 101, respectively. On the other hand, the connecting bolt 102 is provided with male threads that can be screwed into the female threads 111 and 111 of the respective sleeves 101 and 101 over the entire length in the axial direction.

  Here, the axial length LB of the connecting bolt 102 is formed longer by G than the total of the axial lengths LS1, LS2 of the female threads 111, 111 formed on the inner circumference of the pair of sleeves 101, 101, respectively. . Therefore, when both ends of the connecting bolt 102 are respectively screwed into the female threads 111, 111 of the pair of sleeves 101, 101, an axial gap having a length of G or more can always be secured between the pair of sleeves. . By winding the strap 104 around the axial gap, the same effects as those described above can be obtained.

  Still another embodiment of the mechanical joint for reinforcing bars according to the present invention will be described with reference to FIG. In FIG. 4, the parts and parts equivalent to those shown in FIG. 2 are numbered by adding 200 uniformly to the parts and parts shown in FIG. Now, in the rebar mechanical joint shown in FIG. 4, female screws 211 and 211 are screwed over the entire inner circumference of the pair of sleeves 201 and 201. On the other hand, the connecting bolt 202 is provided with male threads that can be screwed into the female threads 211 and 211 of the respective sleeves 201 and 201 over the entire length in the axial direction.

  Now, when using the mechanical joint of the reinforcing bar, one end of the deformed reinforcing bar 203, 203 is inserted into the inner periphery of the other end of the sleeve 201, 201, and the outer periphery of the other end of the sleeve is set to the axial length. Leave the female screws 211 and 211 of LS1 and LS2, respectively, by pressing them with a press or the like to reduce the diameter, and let the inner periphery of the other end of this sleeve be engaged with the bamboo knot of this deformed rebar. Are connected to each other. Here, the axial length LB of the connecting bolt 202 is longer by G than the total length of the axial lengths LS1, LS2 of the female screws 211, 211.

  Therefore, when the connecting bolt 202 is screwed into the female threads 211, 211 of the pair of sleeves 201, 201, both ends of the connecting bolt exceed the positions where they contact the end surfaces of the deformed reinforcing bars 203, 203 on both sides, respectively. Since the sleeve cannot enter the sleeve, an axial gap having a length equal to or longer than G can be ensured between the pair of sleeves. By winding the band 204 in the axial gap, the same effects as those described above can be obtained.

  In addition, about the connection bolt 2 shown in FIG. 2, the left and right male screw parts 22 and 22 can also be unified with either a right-hand thread or a left-hand thread. In this case, the internal threads 11 and 11 provided at one end of the sleeve 1 are also unified as either a right-hand thread or a left-hand thread. In such a configuration, lock nuts 306 and 306 as shown in FIG. 6 are attached to the left and right male screw portions 22 and 22 so that the connecting bolt 2 does not run idle when connecting the main reinforcing bars 3 and 3. Even in such a case, a gap more than the axial length of the central portion 21 of the connecting bolt 2 can be surely secured between the lock nuts 306 and 306, so that the above-described effects can be exhibited. It becomes.

  3 and 4, a female screw made of a right screw is screwed on one of the pair of sleeves 111, 111 and the like, and a female screw made of a left screw is screwed on the other, and the connecting bolt 102 If a male screw part made of a right-hand thread is screwed on one of both ends of the wire and a male screw part made of a left-hand screw is screwed on the other, the deformed reinforcing bars 103, 103, etc. can be connected like a so-called turnbuckle. .

  Since it is possible to avoid a decrease in shear strength, buckling strength, etc., for reinforced concrete columns, it can be widely used in industries related to construction and mechanical joints of rebars.

It is sectional drawing of the mechanical joint of a reinforcing bar. It is the external view of a connecting bolt, and sectional drawing of a center part. It is sectional drawing of the mechanical coupling of another rebar. It is sectional drawing of the mechanical coupling of another rebar. It is a perspective view of the support | pillar made from reinforced concrete. It is an external view of the mechanical joint of the reinforcing bar by a prior art example. It is an external view of the connection bolt by a prior art example. It is an external view of the other connection bolt by a prior art example.

Explanation of symbols

1, 101-301 Sleeve (tubular member)
11, 111, 211 Female thread (sleeve) 2, 102-402 Connecting bolt 21 Central part 22, 422 Male screw part (connecting bolt) 3, 103-303 Main rebar 4, 104-304

Claims (3)

A pair of cylindrical members, and a connecting bolt for connecting the pair of cylindrical members to each other;
On the inner circumference of one end of the pair of cylindrical members, female screws are respectively screwed,
The connecting bolt has a center portion having a predetermined axial length, and a male thread portion screwed at both ends sandwiching the center portion.
The female screw and the male screw can be screwed together,
The maximum diameter of the central portion of the connecting bolt is smaller than the outer diameter of the cylindrical member and larger than the minimum inner diameter of the female screw,
In use, the inner circumference of the other end of the tubular member is connected to the outer circumference of one end of the reinforcing bar, respectively.
Reinforcing bar mechanical joint. A pair of cylindrical members, and a connecting bolt for connecting the pair of cylindrical members to each other;
On the inner circumference of one end of the pair of cylindrical members, female screws are respectively screwed,
At least both ends of the connecting bolt are provided with male screws that can be screwed together with the female screw,
The axial length of the connecting bolt is longer than the sum of the maximum lengths that can be inserted from one end of the tubular member while screwing male screws screwed to both ends of the connecting bolt into the female screws,
In use, the inner circumference of the other end of the tubular member is connected to the outer circumference of one end of the reinforcing bar, respectively.
Reinforcing bar mechanical joint. In Claim 1 or 2, the female screw threaded on one of the pair of cylindrical members is a right-hand thread, and the female thread threaded on the other is a left-hand thread.
One of the male screw parts screwed to both ends of the connecting bolt is a right-hand thread, and the other is a left-hand thread.
The female screw consisting of the right screw and the male screw consisting of the right screw can be screwed together,
The female screw made of the left screw and the male screw made of the left screw can be screwed together.
Reinforcing bar mechanical joint.

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