JP6439329B2 - Composite female screw member and concrete shear reinforcement using the same - Google Patents

Description

  The present invention relates to a composite female screw member used in various industrial fields and a concrete shear reinforcement using the same.

  The connection and attachment of members by bolt fastening are widely used in various industrial applications such as machinery, civil engineering, and construction. However, depending on the attachment part, vibration due to mechanical vibrations or disturbances such as earthquakes can be repeatedly applied as bolts. Act on.

  In such a situation, there is a concern that the bolt may be fatigued and destroyed by the repeated load described above. However, since the damage to the bolt due to the fatigue failure can affect the entire machine or the entire structure, In addition to designing it with sufficient consideration for its fatigue strength, periodic maintenance and inspection are indispensable after installation.

  Here, when a tensile load is applied to the bolt, a tensile stress is generated in the bolt due to a reaction force from the female screw to which the bolt is screwed. This tensile stress is not uniform along the axial direction of the material. First, it becomes the maximum at the position where it engages with the thread of the female screw closest to the head of the bolt, and decreases from the thread toward the tip of the bolt.

  In conventional bolts, when a tensile load is applied, tensile stress concentrates near the insertion opening of the female screw, and fatigue failure often occurs at this cross-sectional position.

  Based on this, Patent Document 1 states that “a part of the top of the screw thread on the bolt head side or the bolt cylinder part side of the male screw part is removed and the screw thread outside toward the bolt head side or the bolt cylinder part side. A bolt having a tapered portion with a reduced diameter ”has been proposed, and according to such a configuration,“ the surface pressure shared by the height of each thread of the tapered portion screwed with the coarse nut is shared. Since the load share of each screw thread of the taper part becomes uniform, when the coarse nut is screwed together, the end face of the coarse nut on the bolt head side or bolt cylindrical part side (inside) It is possible to alleviate the concentration of tension and bending stress on the bottom of the threaded valley of the taper portion in the vicinity, and to greatly improve the fatigue strength ”(paragraph [0005]).

  Further, Non-Patent Document 1 states that “by gradually reducing the screw thread of the bolt, the load sharing of the screw portion is made uniform, the stress concentration is relaxed, and further, the contact of the screw surface is reduced and the fatigue strength is improved”. A possible bolt is disclosed.

JP 2009-174564 A

“CD Bolt”, NS Bolten, Inc. [searched July 8, 2014], Internet <URL: http://www.bolten.co.jp/nsb/newpage3-11.htm>

  However, when the bolt is machined as described above, there is a concern that the cross-sectional area is reduced and the load bearing performance may be lowered, and both require complicated machining and increase the production cost. There has been a problem that its use is limited, for example, it is used for parts that are difficult to inspect.

  Further, the fifth page of the CD bolt catalog referred to by Non-Patent Document 1 describes that “the position where the nut is applied, that is, the end face of the nut is near the center of the CD processing of the bolt” regarding the position of the bolt. As can be seen from the above, since the diameter at the top of the screw thread fluctuates along the axis of the material, it is necessary to be screwed with the female screw in a specific range, unlike ordinary bolts and nuts. There is.

  In other words, the above-described bolt has an optimum range with respect to the portion to be screwed with the female screw. Therefore, a large number of various length sizes must be prepared according to the thickness of the object to be fastened. There was also a problem of lacking.

  The present invention has been made in consideration of the above-described circumstances, and provides a composite female screw member capable of preventing fatigue failure of a bolt in a form excellent in economy and versatility, and a concrete shear reinforcement using the same. For the purpose.

In order to achieve the above object, a composite female screw member according to the present invention comprises a first female screw member that is screwed into a male screw, and a first female screw member that is coaxial with the first female screw member. A second female screw member screwed into the male screw and having an outer diameter larger than that of the first female screw member, and a recess for accommodating the first female screw member is formed in the second female screw member. The first female screw member that is provided on the screw member and faces the inner surface of the concave portion along the axial direction of the male screw when the first female screw member is accommodated in the concave portion. Of the second female screw member, the annular portion surrounding the recess is flush with the fastened object side portion of the first female screw member. a composite female screw member constituting said recess so that, concluded completion Tensile load generated in the male screw in the state is one that is adapted to be dispersed supported by the second female screw member and the first female screw member.

The concrete shear reinforcement according to the present invention is a concrete shear reinforcement as described in claim 2, wherein a composite female screw member is attached as a concrete fixing plate to a male screw formed at an end of a rod. In
The composite female screw member is screwed into the male screw coaxially with the first female screw member and is larger than the first female screw member. And a second female screw member having an outer diameter, and a recess for accommodating the first female screw member is provided in the second female screw member, and the first female screw is provided in the concave portion. When the member is accommodated, the second female inner surface is separated from the inner surface of the recess and the opposing surface of the first female screw member facing the inner surface along the axial direction of the male screw. Of the part facing the opposite end of the rod in the screw member, the annular part surrounding the recess is flush with the part facing the opposite end of the rod in the first female screw member, or The concave portion is configured so that a vertical step is formed.

  Moreover, the concrete shear reinforcement according to the present invention is a spacer arranged so that the separated state is maintained between the inner surface of the recess and the facing surface of the first female screw member facing the inner surface. It is equipped with.

  In the composite female screw member according to the first invention, the second female screw member has a larger outer diameter than the first female screw member and is provided with a recess for accommodating the first female screw member. When the first female screw member is accommodated, the concave portion has an inner surface of the concave portion and an opposing surface of the first female screw member facing the inner surface along the material axis direction of the male screw. In a state of being separated from each other, the annular part surrounding the concave portion in the fastened object side part of the second female screw member is configured to be flush with the fastened object side part of the first female screw member.

  In this way, when the first female screw member and the second female screw member are respectively screwed into the male screw so as to be coaxial, the first female screw member is covered by the portion to be fastened. The second female screw member also comes into contact with the fastened object at its annular portion while being in contact with the fastened object.

  Therefore, the reaction force of the tensile load generated on the male screw to fasten the fastened object is from the fastened object to the fastened object side part of the first female screw member and the annular part of the second female screw member, respectively. It acts and balances the shearing force received from the part where the first female screw member is screwed and the shearing force received from the part where the second female screw member is screwed.

  That is, the tensile load generated in the male screw is not supported by one female screw member as in the prior art, but is dispersedly supported by the first female screw member and the second female screw member. The degree of concentration of the tensile stress generated in the male screw is relaxed as compared with the conventional case, and the fatigue life of the male screw can be greatly extended.

  The annular portion of the second female screw member and the covering of the first female screw member in a state where the inner surface of the recess provided in the second female screw member and the opposing surface of the first female screw member are separated from each other. Since the portion to be fastened is flush with the portion to be fastened, the fastened portion side of the first female screw member and the annular portion of the second female screw member are brought into contact with the fastened object, respectively. Thus, the inner surface of the recess provided in the second female screw member and the opposing surface of the first female screw member are naturally separated from each other.

  Therefore, there is no possibility that direct load transmission occurs between the first female screw member and the second female screw member. Thus, the tensile load generated on the male screw is reduced between the first female screw member and the second female screw member. While being reliably supported by the female screw member, the fatigue life of the male screw can be extended more reliably.

  The composite female screw member according to the first invention is a substitute for a normal female screw member, and can be used for all industrial applications.

  In the concrete shear reinforcement according to the second aspect of the invention, the second female screw member has a larger outer diameter than the first female screw member, and is provided with a recess in which the first female screw member is accommodated. When the first female screw member is accommodated, the concave portion has an inner surface of the concave portion and an opposing surface of the first female screw member facing the inner surface along the material axis direction of the male screw. Of the portion facing the opposite end of the rod in the second female screw member in a separated state (hereinafter simply referred to as the front portion), the annular portion surrounding the recess is the front portion of the first female screw member. It is configured such that a level difference is formed on the same plane or perpendicular to the front portion.

  In this way, the concrete shear reinforcement according to the second invention is screwed into the male screw of the rod so that the first female screw member and the second female screw member are coaxial with each other. When embedded, the first female screw member comes into contact with the concrete at the front portion, and the second female screw member also comes into contact with the concrete at the annular portion surrounding the recess in the front portion.

  Therefore, when a concrete structure undergoes shear deformation due to an earthquake load, the above-described composite female screw member functions as a concrete fixing plate that transmits the tensile load generated on the rod due to the shear deformation of the concrete to the concrete at its end, and The reaction force of the tensile load acts on the front part of the first female screw member and the annular part of the second female screw member through the concrete, respectively, The shearing force received from the location where the first female screw member is screwed and the shearing force received from the location where the second female screw member is screwed are balanced.

  That is, the tensile load generated in the male screw is not supported by one female screw member as in the prior art, but is dispersedly supported by the first female screw member and the second female screw member. The degree of concentration of the tensile stress generated in the male screw is relaxed as compared with the conventional case, and the fatigue life of the male screw can be greatly extended.

  Also, in situations where it is difficult to inspect and maintain fatigue failure because it is buried in concrete, unlike conventional ones, fatigue failure of male threads is prevented in advance, so the earthquake resistance of concrete structures represented by reinforced concrete Can be secured in the long term.

  As described above, the reaction force of the tensile load generated on the rod acts on the front portion of the first female screw member and the annular portion of the second female screw member via the concrete, so that they are not necessarily flush with each other. It is not necessary to be embedded in concrete with a step formed perpendicular to the front part.

  When embedding a concrete shear reinforcement in concrete, it is necessary to prevent direct load transmission from occurring between the inner surface of the recess and the opposite surface. For example, the first female screw member and the second female screw member When the female screw member is screwed into the male screw of the rod, for example, the relative positional relationship at that time is marked in advance so that the inner surface of the recess and the opposing surface are separated from each other, and the screwing operation is performed accordingly. However, if the above-described recess is configured so that the annular portion of the second female screw member is flush with the front portion of the first female screw member, the second female screw member can be used. By simply screwing the first female screw member and the second female screw member into the male screw so that the annular part of the screw member and the front part of the first female screw member are flush with each other, And the opposite surface It becomes possible to separate the stomach, it is easy to quality management in meshing operation industry.

  On the other hand, if a spacer is provided between the inner surface of the recess and the facing surface of the first female screw member facing the inner surface, the screwing operation is performed. Without paying special attention, it is possible to reliably separate the inner surface of the concave portion from the opposing surface.

It is a longitudinal cross-sectional view of the composite female screw member which concerns on 1st Embodiment, (a) is an assembly drawing, (b) is the whole figure after an assembly. It is a figure of the composite female screw member which concerns on 1st Embodiment, (a) is an arrow view seen from the AA line direction, (b) is an arrow view seen from the BB line direction. Explanatory drawing which showed the procedure fastened using the composite female screw member which concerns on 1st Embodiment with the longitudinal cross-section. The longitudinal cross-sectional view which showed a mode that the fastening using the composite female screw member which concerns on 1st Embodiment was completed. Explanatory drawing which showed the load loading condition of the composite female screw member which concerns on 1st Embodiment, the tensile stress distribution of a volt | bolt, and the load balance condition of each member. Explanatory drawing which showed the load loading condition of the conventional female screw member and the bolt screwed to this female screw member, and the tensile stress distribution of a bolt. The perspective view which showed the arrangement | positioning condition of the concrete shear reinforcement tool 75 concerning 2nd Embodiment. The assembly figure which showed concrete shear reinforcement 75 in the longitudinal cross-section. Explanatory drawing which showed the load loading condition of the concrete shear reinforcement tool 75 which concerns on 2nd Embodiment. The longitudinal cross-sectional view which showed the concrete shear reinforcement according to the modification. The longitudinal cross-sectional view which showed the concrete shear reinforcement according to another modification.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a composite female screw member and a concrete shear reinforcement using the same according to the present invention will be described with reference to the accompanying drawings.

[First embodiment]
1 and 2 are views showing a composite female screw member according to the present embodiment. As shown in these drawings, the composite female screw member 1 according to this embodiment includes a first female screw member 3 screwed into a male screw 2, and a male screw 2 coaxially with the first female screw member. And a second female screw member 4 having a larger outer diameter than that of the first female screw member.

  As can be clearly seen in FIG. 1A, the first female screw member 3 has a shape in which a truncated cone extends from one end of a cylindrical body, and a portion to be fastened, which is a side into which the male screw 2 is inserted, is a flat surface. 7, opposite side portions are formed by conical surfaces 8, and a female screw 9 is formed so as to penetrate from one side to the other side.

  As shown in the figure, the second female screw member 4 has a disk shape as a whole, and a recessed portion 5 having a cylindrical inner surface 12a and a conical inner surface 12b is connected to the side on which the male screw 2 is inserted. The female screw 10 is formed so as to penetrate from the bottom of the concave portion to the opposite side of the fastened object side portion, and the fastened object side portion extending around the concave portion 5 is a concave portion. 5 becomes an annular portion 11 surrounding 5.

  Here, as can be seen well in FIG. 5B, the recess 5 is formed along the conical inner surface 12b of the recess 5 and the material axis direction of the male screw 2 when the first female screw member 3 is accommodated in the recess. The annular portion 11 is configured to be flush with the flat surface 7 in a state where the facing surface of the first female screw member 3 facing the conical inner surface, that is, the above-described conical surface 8 is separated from each other.

  The first female screw members 3 are separated from each other so that the outer peripheral surfaces of the first female screw members 3 do not generate friction that interferes with the cylindrical inner surface 12a of the recess 5 formed in the second female screw member 4. Or smooth the surfaces.

  FIG. 3 shows a procedure for fastening the plate 31 as a fastening object to the fastening side main body by screwing the composite female screw member 1 to the male screw 2 extending from the fastening side main body 32. Here, the fastening side main body 32 and the plate 31 are an equipment main body, accessory parts attached to the equipment main body, a structure main body and a brace material end plate connected to the structure main body, bolts and nuts. All combinations that are concluded apply.

  In order to fasten the plate 31 to the fastening side main body 32 using the composite female screw member 1, first, the male screw 2 is inserted into the bolt hole 33 formed in the plate 31, as shown in FIG. Next, the plate is disposed on the fastening side main body 32, and then the first female screw member 3 is screwed onto the male screw 2 so that the flat surface 7 is in contact with the plate 31.

  Next, as shown in FIG. 2B, the second female screw member 4 is disposed so as to cover the first female screw member 3, and then the annular portion 11 of the second female screw member 4 is disposed. The female screw 10 of the second female screw member is screwed into the male screw 2 such that the female screw 10 contacts the plate 31.

  FIG. 4 shows a state in which the plate 31 is fastened to the fastening side main body 32 using the composite female screw member 1.

  In the composite female screw member 1 according to the present embodiment, when the first female screw member 3 and the second female screw member 4 are respectively screwed into the male screw 2 so as to be coaxial, FIG. As shown in FIG. 1, the first female screw member 3 is in contact with the plate 31 that is the fastened object at the flat surface 7 that is the fastened object side part, and the second female screw member 4 is also the annular part 11 thereof. It contacts the plate 31.

  Therefore, the reaction force of the tensile load generated on the male screw 2 for fastening the plate 31 is applied from the plate 31 to the flat surface 7 of the first female screw member 3 and the annular portion 11 of the second female screw member 4. Works.

  The reaction force of the above-described tensile load, as can be seen well in FIG. 5 (b), is the shear force and the second female screw received from the portion of the male screw 2 where the first female screw member 3 is screwed. It balances with the shearing force received from the place where the member 4 is screwed.

  Therefore, the tensile load generated in the male screw 2 is distributed and supported by the first female screw member 3 and the second female screw member 4, and the tensile stress of the male screw 2 is as shown on the right side of FIG. In addition, the degree of concentration of the male screw 2 formed on the first female screw member 3 at the opening cross-sectional position is alleviated and decreases relatively gently along the depth direction.

  Here, the left side of FIG. 6A shows the overall balance in a state where the composite female screw member 1 is screwed to the male screw 2, and the upper part of FIG. The balance of forces acting on the female screw member 4 is depicted, the middle row depicts the balance of forces acting on the first female screw member 3, and the lower row depicts the balance of forces acting on the male screw 2.

  On the other hand, conventionally, the reaction force of the tensile load generated in the male screw 2 acts only on the fastened object side portion of the nut 61 as the female screw member as shown in FIG. As shown on the right side of FIG.

  As described above, according to the composite female screw member 1 according to this embodiment, the second female screw member 4 having an outer diameter larger than that of the first female screw member 3 is added to the first female screw member. The second female screw member is provided in a state in which the conical inner surface 12b and the conical surface 8 of the first female screw member 3 facing the conical inner surface are spaced apart from each other. Since the four annular portions 11 are configured to be flush with the flat surface 7 of the first female screw member 3, the tensile load generated on the male screw 2 is supported by a single nut 61 as in the prior art. Instead, the first female screw member 3 and the second female screw member 4 are distributed and supported. Thus, the tensile stress (FIG. 5 (a)) generated in the male screw 2 is the conventional tensile stress ( The degree of concentration is greatly relaxed compared to Fig. 6), and the fatigue life of the male screw 2 is greatly extended. It can be.

  Further, according to the composite female screw member 1 according to the present embodiment, the conical inner surface 12b of the recess 5 provided in the second female screw member 4 and the conical surface 8 of the first female screw member 3 are separated from each other. Since the annular portion 11 of the second female screw member 4 and the flat surface 7 of the first female screw member 3 are flush with each other in the state, the flat surface 7 of the first female screw member 3 is formed. And the annular portion 11 of the second female screw member 4 are brought into contact with the plate 31, respectively, so that the conical inner surface 12b of the recess 5 provided in the second female screw member 4 and the cone of the first female screw member 3 are provided. Naturally separate from the surface 8.

  Therefore, there is no possibility that direct load transmission occurs between the first female screw member 3 and the second female screw member 4, and thus the tensile load generated on the male screw 2 is the first female screw member 3. And the second female screw member 4 are surely distributed and supported, whereby the fatigue life of the male screw 2 can be extended more reliably.

[Second Embodiment]
Next, the concrete shear reinforcement according to the second embodiment will be described. Note that components that are substantially the same as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 7 is a perspective view showing an arrangement state of the concrete shear reinforcement 75 according to the second embodiment. As shown in the figure, the concrete shear reinforcement 75 according to the present embodiment includes a main reinforcement 73a arranged vertically along one wall surface, and a distribution bar 74a arranged horizontally so as to be orthogonal to the main reinforcement, Applied to a reinforced concrete wall 71 composed of a main bar 73b arranged vertically along the other wall surface, a distribution bar 74b horizontally arranged perpendicular to the main bar, and a concrete 72 embedding them. And this concrete shear reinforcement is arrange | positioned so as to be orthogonal to a wall surface in the form spanned over the intersection location of the main reinforcement 73a and the distribution bar 74a, and the intersection location of the main reinforcement 73b and the distribution reinforcement 74b.

  As shown in FIG. 8, the concrete shear reinforcement 75 is composed of a rod 76 and composite female screw members 1, 1 attached to male screws 2, 2 formed at each end of the rod. The female screw member is a concrete that suppresses the shear deformation of the concrete 72 by preventing the end of the rod 76 from coming out due to the tensile load when a tensile load is generated on the rod 76 due to the shear deformation of the concrete 72 during an earthquake. Functions as a fixing plate.

  In addition, since the composite female screw member 1 has substantially the same configuration as that of the first embodiment, the description thereof is omitted here, but the fastened object side portion in the first embodiment is the opposite end portion of the rod 76. In this embodiment, the front part of the first female screw member 3 is a flat surface 7, and the front part of the second female screw member 4 is surrounded by the recess 5. The front part which spreads out becomes the annular part 11.

  In order to assemble the concrete shear reinforcement 75, the first female screw member 3 and the second female screw member 4 may be sequentially screwed into the male screws 2 of the rod 76 so as to be coaxial.

  When performing the screwing operation, the conical inner surface 12b of the recess 5 provided in the second female screw member 4 and the conical surface 8 of the first female screw member 3 are as shown in FIG. So that the annular portion 11 of the second female screw member 4 and the flat surface 7 of the first female screw member 3 are flush with each other.

  In order to make the annular portion 11 of the second female screw member 4 and the flat surface 7 of the first female screw member 3 flush with each other, for example, a flat steel plate in which a slit into which the male screw 2 is inserted is formed. A jig is prepared and set to the male screw 2 so that the male screw 2 is inserted into the slit, and then the annular portion 11 of the second female screw member 4 and the flat surface 7 of the first female screw member 3. They are screwed together until they come into contact with the steel jig, and after the work, the steel jig may be removed.

  It should be noted that the screwing position of the first female screw member 3 and the second female screw member 4 is shifted before the concrete placement, and the conical inner surface 12b of the recess 5 provided in the second female screw member 4 and the second If there is a possibility that the separated state of the female screw member 3 from the conical surface 8 is not ensured, for example, nuts are screwed into the male screw 2 from both sides of the composite female screw member 1 to It is only necessary to prevent the deviation.

  When the assembly of the concrete shear reinforcement 75 is completed, the reinforced concrete wall 71 is then placed by placing the main bars 73a, 73b and the distribution bars 74a, 74b together with the procedure described above, and then placing and hardening the concrete 72. To construct.

  In the concrete shear reinforcement 75 according to the present embodiment, as shown in FIG. 9, the first female screw member 3 abuts the concrete 72 on the flat surface 7, and the second female screw member 4 is also in front. Among the parts, the concrete part 72 comes into contact with the annular part 11 surrounding the recess.

  Therefore, when the concrete 72 undergoes shear deformation during the earthquake and a tensile load is generated on the rod 76, the reaction force of the tensile load is a flat surface of the first female screw member 3 through the concrete 72 as shown in FIG. 7 and the annular portion 11 of the second female screw member 4 respectively.

  And the reaction force of the above-mentioned tensile load is the same as described in FIG. 5B of the first embodiment, the shearing force received from the portion of the male screw 2 where the first female screw member 3 is screwed and The tensile load generated in the male screw 2 is distributed and supported by the first female screw member 3 and the second female screw member 4 in order to balance the shearing force received from the place where the second female screw member 4 is screwed. .

  On the other hand, in the conventional concrete shear reinforcement in which a single female screw member is screwed to each end of the rod, the reaction force of the tensile load generated on the male screw 2 is described with reference to FIG. 6 of the first embodiment. Similarly, it acts on the front part of the female screw member having a single structure, and the tensile stress of the male screw 2 is concentrated at the opening cross-sectional position of the female screw member.

  As described above, according to the concrete shear reinforcement 75 according to this embodiment, the first female screw member is connected to the second female screw member 4 having a larger outer diameter than the first female screw member 3. Since the concave portion 5 is provided, the tensile load generated in the male screw 2 is not supported by one female screw member as in the prior art, but the first female screw member 3 and the second female screw 2 are supported. The tensile stress (see FIG. 5 (a) of the first embodiment) generated in the male screw 2 is distributed and supported by the screw member 4, and the concentration degree is much larger than the conventional tensile stress (also see FIG. 6). The fatigue life of the male screw 2 can be greatly extended.

  Further, according to the concrete shear reinforcing tool 75 according to the present embodiment, the conical inner surface 12b of the recess 5 provided in the second female screw member 4 and the conical surface 8 of the first female screw member 3 are separated from each other. Since the annular portion 11 of the second female screw member 4 and the flat surface 7 of the first female screw member 3 are flush with each other in the state, the flat surface 7 of the first female screw member 3 is formed. And the annular portion 11 of the second female screw member 4 are screwed together so that the conical inner surface 12b of the recess 5 provided in the second female screw member 4 and the first female screw member 3 can be easily ensured to be separated from the conical surface 8.

  Therefore, direct load transmission between the first female screw member 3 and the second female screw member 4 can be prevented by simple quality control, and thus the tensile load generated on the male screw 2 is The first female screw member 3 and the second female screw member 4 are securely supported by dispersion, and thereby the fatigue life of the male screw 2 can be reliably extended.

  In addition, according to the concrete shear reinforcing tool 75 according to the present embodiment, since it is embedded in the concrete 72, in a situation where it is difficult to inspect and maintain the fatigue failure, unlike the conventional case, the fatigue failure of the male screw 2 has not occurred. Therefore, it is possible to ensure the earthquake resistance of the reinforced concrete wall 71 for a long time.

  In the present embodiment, the annular shape of the second female screw member 4 is such that the conical inner surface 12b of the recess 5 provided in the second female screw member 4 and the conical surface 8 of the first female screw member 3 are separated from each other. The first female screw is configured such that the portion 11 and the flat surface 7 of the first female screw member 3 are flush with each other, and the annular portion 11 and the flat surface 7 are flush with each other. The screwing position between the member 3 and the second female screw member 4 is adjusted at the construction site.

  However, this configuration is a configuration for facilitating adjustment of the screwing position at the construction site, and is installed if the separated state between the conical inner surface 12b and the conical surface 8 can be secured separately. Since the concrete (fresh concrete) is surely in contact with the annular portion 11 of the second female screw member 4 and the flat surface 7 of the first female screw member 3, the annular portion and the flat surface are not necessarily flush with each other. It is not necessary to configure the recess 5 so as to be.

  For example, if the first female screw member 3 and the second female screw member 4 are pre-marked with respect to the relative positional relationship between the conical inner surface 12b and the conical surface 8 of the recess 5 that are separated from each other, In this case, it is possible to perform screwing adjustment using this marking.

  Further, when the screwing position adjustment at the construction site is possible, for example, as shown in FIG. 10A, the flat surface 7 of the first female screw member 3 is the second female screw member 4. Alternatively, a vertical step having a shape positioned rearward of the annular portion 11 may be formed. As shown in FIG. 10B, the flat surface 7 of the first female screw member 3 is a second female member. A configuration in which a vertical step having a shape positioned in front of the annular portion 11 of the screw member 4 may be used.

  In these configurations, the reaction force against the tensile load of the male screw 2 acts in the same manner as in the above-described embodiment via the concrete 72 as shown in FIG. The point that the load is dispersedly supported by the first female screw member 3 and the second female screw member 4 is not different from the above-described embodiment.

  Further, in the present embodiment and the above-described modification, the screwing position is set at the construction site so that the annular portion 11 of the second female screw member 4 and the flat surface 7 of the first female screw member 3 are flush with each other. Although the relative screwing position of the first female screw member 3 and the second female screw member 4 is adjusted by using a pre-marked mark or a pre-marked mark, the relative screwing position is shown in FIG. As described above, the spacer 101 may be interposed between the conical inner surface 12 b and the conical surface 8 of the recess 5.

  According to such a configuration, whether the annular portion 11 of the second female screw member 4 and the flat surface 7 of the first female screw member 3 are flush with each other, or is a vertical step formed between them? Regardless of this, it is possible to more reliably form the above-described separated state, and the construction management on site is not required.

  Here, FIG. 11A shows a case where the flat surface 7 of the first female screw member 3 is flush with the annular portion 11 of the second female screw member 4, and FIG. When the flat surface 7 of the female screw member 3 is located behind the annular portion 11 of the second female screw member 4, FIG. 11 (c) shows that the flat surface 7 of the first female screw member 3 is the first one. The case where it is located ahead rather than the cyclic | annular part 11 of the 2 internal thread member 4 is shown.

  The spacer 101 can be composed of an elastic member such as an annular rubber material or an annular disc spring, for example. In such a configuration, when the spacer 101 is about to contract, due to a reaction force from the spacer, Since the torque required for screwing becomes larger than before, the screwing operation may be terminated at that time.

  The spacer 101 is configured such that the reaction force during contraction is sufficiently smaller than the tensile load generated in the male screw 2 or the reaction force.

DESCRIPTION OF SYMBOLS 1 Composite female screw member 2 Male screw 3 1st female screw member 4 2nd female screw member 5 Recessed part 7 Flat surface (fastened object side part, front part)
8 Conical surface (opposite surface)
11 annular part (fastened object side part, front part)
12a Cylinder inner surface (inner surface of recess)
12b Conical inner surface (inner surface of recess)
31 Fastened object 75 Concrete shear reinforcement 76 Rod

Claims (3)

A first female screw member screwed into the male screw, and a second female screw screwed into the male screw coaxially with the first female screw member and having a larger outer diameter than the first female screw member The second female screw member is provided with a recess for accommodating the first female screw member, and when the first female screw member is accommodated in the concave portion, the concave portion is provided. In the second female screw member in a state where the inner surface of the second female screw member and the opposing surface of the first female screw member facing the inner surface along the material axis direction of the male screw are separated from each other. Among them, the female female member is a composite female screw member in which the concave portion is configured so that the annular portion surrounding the concave portion is flush with the fastened object side portion of the first female screw member, and the male screw is in a state where fastening is completed. The tensile load generated on the screw is the first female screw member and the second Composite female screw member, characterized in that is adapted to be dispersed supported by a screw member. In a concrete shear reinforcement that is designed to attach a composite female screw member as a concrete fixing plate to a male screw formed at the end of a rod,
The composite female screw member is screwed into the male screw coaxially with the first female screw member and is larger than the first female screw member. And a second female screw member having an outer diameter, and a recess for accommodating the first female screw member is provided in the second female screw member, and the first female screw is provided in the concave portion. When the member is accommodated, the second female inner surface is separated from the inner surface of the recess and the opposing surface of the first female screw member facing the inner surface along the axial direction of the male screw. Of the part facing the opposite end of the rod in the screw member, the annular part surrounding the recess is flush with the part facing the opposite end of the rod in the first female screw member, or The concave portion is configured so that a vertical step is formed. Concrete shear reinforcement tool. 3. A concrete shear reinforcement device according to claim 2, further comprising a spacer arranged so that the separated state is maintained between the inner surface of the recess and the facing surface of the first female screw member facing the inner surface. .

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