JP4690225B2 - Screw alloys for screw rebar - Google Patents

Description

  The present invention relates to a hardware that is screwed into a screw rebar.

  An example of a hardware that is screwed to the screw rebar is a fixing hardware shown in Patent Document 1. This fixing hardware fixes the end of the screw rebar to the concrete by screwing it to the end of the screw rebar as the column main bar or beam main bar at the intersection (joint part) of the column and beam. is there.

  As shown in FIG. 15, the fixing hardware 10 has a cylindrical portion 11 and an annular flange portion 12 protruding radially and outwardly from the outer periphery of the axial rear end of the cylindrical portion 11. . A female screw portion 14 is formed on the inner periphery of the cylindrical portion 11. Further, an injection port (not shown) is formed in the peripheral wall of the cylindrical portion 11 so as to be located in the center in the axial direction.

  In a state where the cylindrical portion 11 is screwed to the end portion of the screw rebar 20, the grout (filler) injected from the inlet is between the inner periphery of the female screw portion 14 and the outer periphery of the screw rebar 20. The fixing metal 10 is fixed to the screw rebar 20 by being filled and cured.

In the state where the fixing hardware 10 is fixed to the end portion of the screw rebar 20 as described above, concrete is placed in the joint portion. The flange portion 12 of the fixing hardware 10 buried in the concrete serves as a resistance to the axial tensile load applied to the screw rebar 20, and helps fix the screw rebar 20.
JP-A-6-57952

  By the way, since the screw rebar 20 is manufactured by rolling, the screw node 21 is not formed with high accuracy like a mechanical screw, and a relatively large error occurs in the pitch of the screw node 21 (in other words, the lead angle). For example, an error of 0.2 mm occurs with respect to a standard pitch of 16.0 mm.

When the female screw portion 14 of the fixing metal 10 is formed so as to be aligned with a screw node 21 having a standard pitch and to be screwed with a predetermined clearance (for example, 0.4 mm), the fixing metal 10 has a pitch of the screw nodes 21. It cannot be screwed into the screw rebar 20 which is 0.2 mm smaller than the standard pitch (the lead angle is smaller than the standard lead angle). Only by rotating the fixing metal 10 twice, both the front spiral surface 50a ′ and the rear spiral surface 50b ′ of the thread 50 ′ of the female screw portion 14 respectively contact the portions separated by two in the screw node 21. This is because the screwing can no longer proceed.
Similarly, the fixing metal fitting having the standard pitch specification cannot be screwed to the threaded reinforcing bar 20 having the pitch of the screw nodes 21 larger than the standard pitch.

  Therefore, in actuality, it is assumed that the screw joint 21 is at the upper limit and the lower limit of the pitch error range. Even in these cases, the screw thread 50 of the fixing hardware 10 can be secured so that the predetermined clearance can be secured. The width of '(the dimension in the axial direction of the female screw portion 14) is narrowed.

  However, if the width of the thread 50 'of the fixing hardware 10 is narrowed as described above, an excessive clearance (indicated by symbol X in FIG. 15) occurs when the screw joint 21 of the screw rebar 20 has a standard pitch. . This excessive clearance X causes the following inconvenience.

The fixing hardware 10 is movable by the clearance X with respect to the screw rebar 20 after being screwed to the screw rebar 20 and before grout injection. Therefore, as shown in FIG. 15, the fixing metal 10 is at the most advanced position, and the grout is injected and hardened in a state where the front spiral surface 50a ′ of the screw thread 50 ′ hits the screw node 21 of the screw reinforcing bar 20. Sometimes. In this case, for example, when the screw rebar 20 receives a large tensile load in the direction of an arrow due to a large earthquake, the screw node 21 moves by the clearance X until it breaks the grout and hits the rear spiral surface 50b ′ of the thread 50 ′. .
When the clearance X is excessive, the relative movement amount of the screw rebar 20 described above becomes large, and the strength of the building is reduced.

  In order to reduce the amount of relative movement with respect to the fixing hardware 10 when the screw rebar 20 receives a large tensile load, the position where the rear spiral surface 50 b ′ of the thread 50 ′ of the fixing hardware 10 hits or approaches the screw node 21. In this case, it is necessary to inject grout. However, the position management of the fixing hardware for each grout injection deteriorates workability.

  In order to solve the above-described problem, a first aspect of the present invention includes a female screw portion, a screw rebar is screwed into the female screw portion, and a filler between the inner periphery of the female screw portion and the outer periphery of the screw rebar. In the threaded alloy fixed to the screw rebar, the thread width of the female thread part changes along the spiral of the thread thread, and the thread width in the intermediate area of the female thread part is the largest. It is wide and the screw thread width in the region near both ends of the female screw portion is the narrowest.

In the above aspect, in order to maximize the thread width in the intermediate region of the screw alloy, the amount of the relative movement of the screw alloy relative to the screw rebar in the intermediate region, that is, the clearance can be minimized or moderate. In addition, by narrowing the thread width in the vicinity of both ends of the screw alloy, even if there is an error in the screw joint pitch of the screw rebar, there is no interference with the screw joint, and screwing into the screw rebar is not hindered. .
As described above, the screw alloy material can reduce the relative movement amount with respect to the screw rebar when a large tensile load is applied while allowing the error range of the screw rebar.

In the above aspect, preferably, the thread width gradually decreases from the intermediate region of the female screw portion toward both ends.
According to this, the thread width can be made relatively wide corresponding to the error of the thread joint pitch of the thread reinforcement, and the thread strength can be increased.

More preferably, the thread of the female screw portion has a spiral surface facing one side in the axial direction of the female screw portion and a spiral surface facing the other side, and the spiral surface facing the one side is the female screw portion. A first spiral surface portion located in a region on one side of the axial direction and a second spiral surface portion located in a region on the other side of the female screw portion, and the spiral surface facing the other side is the one side region A third spiral surface portion located in the second region and a fourth spiral surface portion located in the other region, the lead angles of the first and fourth spiral surface portions being constant and equal to each other, The lead angles of the three spiral surface portions are constant and equal to each other, and are different from the lead angles of the first and fourth spiral surface portions.
According to this, the lead angles of the first and fourth spiral surface portions are substantially matched with one limit value in the error range of the lead angle of the screw node, and the lead angles of the second and third spiral surface portions are screwed. If it is made to substantially coincide with the other limit value in the error range of the lead angle of the node, the thread width can be made as wide as possible, and the thread strength can be further increased.

In the above aspect, preferably, the thread width in the intermediate region of the female screw portion is constant, and the thread width in the region near both ends is constant.
According to this, it becomes easy to manufacture the fixing hardware.

More preferably, the female thread portion has a transition region in which the thread width decreases toward the region near both ends between the intermediate region where the thread width is constant and the region near both ends.
According to this, it becomes much easier to manufacture the fixing hardware.

  In another aspect of the present invention, a screw rebar is provided by having a female screw portion, screwing a screw rebar into the female screw portion, and filling a filler between the inner periphery of the female screw portion and the outer periphery of the screw rebar. The thread width of the female thread portion changes along the spiral of the thread, the thread width in the region near one end of the female thread portion is the widest, and the region in the region near the other end It is characterized by the smallest thread width.

  In the other aspect, in order to maximize the thread width in the one end side region of the screw alloy, the amount of the relative movement of the screw alloy relative to the screw rebar, that is, the clearance is minimized or moderately mainly in the region near the one end. can do. Moreover, by narrowing the thread width in the vicinity of the other end of the screw alloy, even if there is an error in the screw joint pitch of the screw rebar, there is no interference with the screw joint, and screwing into the screw rebar is prevented. Absent.

In the other aspect, preferably, the thread width of the female screw portion is gradually narrowed from one end to the other end.
According to this, the thread width can be made relatively wide corresponding to the error of the thread joint pitch of the thread reinforcement, and the thread strength can be increased.

More preferably, the female screw portion has a spiral surface facing one side in the axial direction and a spiral surface facing the other side, and the lead angle of the spiral surface facing the one side and the spiral surface facing the other side is It is constant and different from each other.
According to this, the lead angle of the spiral surface facing one side is made to substantially coincide with one limit value in the error range of the lead angle of the screw node, and the lead angle of the spiral surface facing the other side is made the error of the lead angle of the screw node. If it is made to substantially coincide with the other limit value in the range, the thread width can be made as wide as possible, and the thread strength can be further increased.

In the other aspect, preferably, the thread width in the region near the one end is constant, and the thread width in the region near the other end is constant.
According to this, it becomes easy to manufacture the fixing hardware.

More preferably, the female thread portion has a transition region in which the thread width decreases from the region near one end to the region near the other end between the region near one end and the region near the other end where the thread width is constant. have.
According to this, it becomes much easier to manufacture the fixing hardware.

  Preferably, the center in the width direction of the thread of the female thread portion passes through a reference spiral having a constant lead angle along the thread.

  According to the present invention, the screw alloy material can reduce the relative movement amount with respect to the screw rebar when a large tensile load is applied while allowing the error range of the screw rebar.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, a fixing metal 10 (a threaded alloy for a screw rebar) made of a casting is provided on a cylindrical cylindrical portion 11 and an outer periphery of one end of the cylindrical portion 11, and protrudes radially and outwardly. And an annular collar 12. Both ends of the cylindrical portion 11 are openings 13.

A female screw portion 14 is formed on the inner periphery of the cylindrical portion 11. An annular groove 15 is formed on the inner periphery of the center of the tube portion 11 to block the thread 50 of the female screw portion 14. The diameter of the groove 15 is equal to the valley diameter of the female screw portion 15.
A grout inlet 16 is formed in the central peripheral wall of the cylindrical portion 11 and is continuous with the groove 15.

As shown in FIG. 2, the fixing hardware 10 is screwed into, for example, an end portion of a screw rebar 20 serving as a beam main bar located in a joint portion. In FIG. 2, the annular groove 15 is not shown.
In this screwed state, grout (filler) is injected from the inlet 13. This grout goes around the annular groove 15, and goes from here to the opening 13 at both ends through the space between the cylindrical portion 11 and the screw rebar 20.

The grout is cured in a state where the space between the inner periphery of the female screw portion 14 and the outer periphery of the screw rebar 20 is satisfied. By this curing, the fixing metal 10 is fixed to the end of the screw rebar 20. Thereafter, concrete is placed in the joint, and the fixing hardware 10 and the screw rebar 20 are embedded in the concrete.
When the screw rebar 20 receives a tensile load in the direction of the arrow in FIG. 2, the fixing hardware 10 becomes a resistance against the concrete, and the load can be received.

  Next, features of the present invention will be described. Referring to FIG. 1, the width W of the screw thread 50 of the female screw part 14 (dimension in the axial direction of the female screw part 14) changes along the spiral of the screw thread 50, and includes a middle including the center. It is widest in the region, gradually narrows toward both ends, and narrowest in the region near both ends.

  The screw thread 50 of the female screw portion 14 includes a spiral surface 50a (one spiral surface) located on the front side in the axial direction of the female screw portion 14 (advancing direction of the fixing hardware 10) and a rear side (the fixing metal 10). And a spiral surface 50b (the spiral surface on the other side) located in the backward direction). In this embodiment, the width W is defined as a dimension between locations where the screw nodes 21 of the screw rebar 20 abut on the spiral surfaces 50a and 50b.

  Next, the characteristics of the female screw portion 14 will be described in detail with reference to FIGS. In order to make the explanation easy to understand, the annular groove 15 is not shown in these drawings, and it is assumed that the thread 50 is not blocked by the annular groove 15. Further, the screw nodes 21 of the screw rebar 20 are formed at two positions facing each other by 180 ° when viewed from the axial direction, and are intermittently formed along the spiral, but this is assumed to be continuous.

  3 to 7 are development views of the thread 50 of the female screw portion 14. In the drawing, the left-right direction is the axial direction of the female screw portion 14, the lower right represents the front end, and the upper left represents the rear end. 4 to 6, the fixing hardware 10 is shown screwed to the screw rebar 20. FIG. 4 shows a case where the screw joint 21 of the screw reinforcing bar 20 has a standard pitch (standard lead angle), FIG. 5 shows a case where the screw joint 21 has a lower limit pitch (lower limit lead angle) of the error range, and FIG. 21 indicates the case of the upper limit pitch (upper limit lead angle) of the error range.

  In order to facilitate understanding of the features of the invention, in FIGS. 3 to 7, the pitch (lead angle) of the thread 50 and the threaded joint 21 and the width W of the thread 50 are exaggerated. The change of the width W is exaggerated. Note that the front and rear end portions of the thread 50 are incomplete because they are cut at both end surfaces of the fixing hardware 10.

  In the present embodiment, the screw fitting to the screw rebar 20 is completed by turning the fixing hardware 10 about five times. In FIG. 4, the screw nodes 21 adjacent to the screw threads 50 are numbered R1 to R5 in order of one turn from the front. Since the screw node 21 of the screw rebar 20 is shown on both sides of the screw thread 50, the same part of the screw node 21 is shown redundantly. For example, the region R2 for one turn of the screw node 21 will be described. This region R2 is shown on the rear side of the front end portion of the screw thread 50 and on the front side of the screw thread 50 part delayed by one turn from this part. Is also shown.

  Note that the width W of the screw thread 50 of the fixing hardware 10 is preferably determined so as to ensure a predetermined clearance. However, in order to facilitate understanding, the clearance will be described as zero.

As shown in FIG. 3, the front spiral surface 50 a of the screw thread 50 includes a first spiral surface portion 51 located in the front region (lower right region in the drawing) of the female screw portion 14 and the rear region (upper left in the drawing). And a second spiral surface portion 52 located in the side region). An intersection of these spiral surface portions 51 and 52 is indicated by a symbol P1 in the figure.
The rear spiral surface 50b of the screw thread 50 has a third spiral surface portion 53 and a rear fourth spiral surface portion 54 located in the front region. An intersection of these spiral surface portions 53 and 54 is indicated by a symbol P2 in the figure.

The first spiral surface portion 51 and the fourth spiral surface portion 54 have a certain lead angle, are parallel to each other, and coincide with the spiral surfaces A1 and A2, respectively.
Similarly, the second spiral surface portion 52 and the third spiral surface portion 53 also have a certain lead angle, are parallel to each other, and coincide with the spiral surfaces B1 and B2, respectively.

As shown in FIG. 5, the spiral surfaces A1 and A2 represent the spiral surface on the rear side and the front spiral surface of the screw node 21 when the screw node 21 is at the lower limit pitch (lower limit lead angle).
Therefore, as shown in FIG. 5, when the screw node 21 has the lower limit pitch, the thread 50 is inserted between the spiral surfaces A1 and A2 of the screw node 21 (the fixing metal 10 is screwed into the end of the screw rebar 21). In the front spiral surface 50a of the thread 50, the first spiral surface portion 51 and the fourth spiral surface portion 54 come into contact with the spiral surfaces A1 and A2 of the screw node 21, respectively. Becomes zero.

As shown in FIG. 6, the spiral surfaces B1 and B2 represent a spiral surface on the rear side and a front spiral surface of the screw node 21 when the screw node 21 is at the upper limit pitch (upper limit lead angle).
Therefore, as shown in FIG. 6, when the screw node 21 has an upper limit pitch, the thread 50 is inserted between the spiral surfaces B1 and B2 of the screw node 21 (the fixing hardware 10 is screwed into the end of the screw rebar 21). In this state, the second spiral surface portion 52 and the third spiral surface portion 53 are in contact with the spiral surfaces B1 and B2 of the screw node 21 on the front spiral surface 50a of the screw thread 50, and the axial clearance is It becomes zero.

  When the screw node 21 has a standard pitch, as shown in FIG. 4, the intersections P1 and P2 of the screw thread 50 are almost in contact with the screw node 21, and the axial clearance is zero.

  When the shape of the screw thread 50 is determined by the spiral surfaces A1, A2, B1, and B2 as described above, as shown in FIG. 3, the screw in the central region Rm (intermediate region) between the intersecting portions P1 and P2 is necessarily formed. The width W of the peak 50 is constant and maximum, the width W gradually decreases from the central region Rm toward both ends, and becomes the minimum in the region near both ends Re. A line connecting the centers of the threads 50 coincides with the reference spiral L. The reference spiral L substantially coincides with the standard pitch spiral of the screw node 21.

According to the above configuration, as long as the pitch of the screw nodes 21 of the screw rebar 20 is within the error range, the fixing hardware 10 can be screwed into the screw rebar 20.
Moreover, the clearance between the screw thread 50 of the fixing hardware 10 and the screw node 21 of the screw rebar 20 can be zero regardless of the pitch error of the screw node 21. As a result, even if a large tensile load is applied in a state where the fixing metal 10 is fixed to the screw rebar 20 by grout filling, the fixing metal 10 is prohibited from moving relative to the screw rebar 20.

  In the present embodiment, the region near both ends Re is a region having a complete mountain width in the vicinity of both ends of the female screw portion 14, and indicates approximately one turn.

  As shown in FIG. 7, it can be seen that the thread 50 of the present embodiment swells in the width direction as compared with a conventional constant width thread 50 '. Also from this comparison, it can be understood that excessive clearance can be avoided when the screw joint 21 is at or close to the standard pitch by making the central region Rm wider.

  In the above embodiment, the thread width is maximized in the central region Rm of the female screw portion 21, but the thread width can also be maximized in a region (intermediate region) that is shifted to either end from the center.

Next, another embodiment of the present invention will be described. In these embodiments, components corresponding to the preceding embodiments are given the same reference numerals in the drawings, and description thereof is omitted.
In the second embodiment shown in FIG. 8, the width of the screw thread 50 is made narrower in the region excluding the central region Rm than in the first embodiment. More specifically, the region near both ends Re has a constant width over a predetermined length. The width of the region near both ends Re is narrower than the width of the central region Rm, and is equal to the width at both ends of the first embodiment. Between the center region Rm and the region near both ends Re is a transition region Rs whose width becomes narrower toward both ends.

  In the second embodiment, both the front spiral surface 50a and the rear spiral surface 50b recede from the spiral surfaces A1, A2, B1, and B2 in the region near both ends Re and the transition region Rs. Therefore, the line connecting the centers of the threads 50 coincides with the standard spiral L of the standard pitch.

  As in the second embodiment, the third embodiment shown in FIG. 9 has a central region Rm having a constant width and a region near both ends Re having a constant width. However, the front spiral surface 50a coincides with the spiral surface A1 in the front end vicinity region Re and transition region Rs located in the front region of the female screw portion 14, and the rear end vicinity region Re and transition region Rs located in the rear region. In FIG. 2, the surface is retracted from the spiral surface B1. Similarly, the rear spiral surface 50b coincides with the spiral surface A2 in the rear end vicinity region Re and transition region Rs located in the rear region, and in the front end vicinity region Re and transition region Rs located in the front region, the spiral surface B2 It is more backward.

Contrary to the third embodiment, the front spiral surface 50a may be retracted from the spiral surface A1, and the rear spiral surface 50b may be retracted from the spiral surface A2, so that the thread width in the region Re near both ends may be constant. .
Further, the spiral surfaces 50a and 50b may be configured to draw a line between the most receding line in FIG. 8 and the most swollen line in FIG. 3, or the most receding line in FIG. You may comprise so that the line between the most swollen lines may be drawn.
In some embodiments, the thread width may be maximum at only one location. In this case, the region including the maximum thread width is the intermediate region.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS. In this embodiment, the width of the thread 50 is the largest in the front end side region Rf (one end side region) and gradually decreases toward the rear end, and the rear end side region Rr (other end side region). Then the width is the narrowest. The front spiral surface 50a of the screw thread 50 coincides with the spiral surface B1, and the rear spiral surface 50b coincides with the spiral surface A2. A line connecting the centers of the threads 50 coincides with the reference spiral L having a standard pitch.

In the fourth embodiment, as shown in FIG. 12, when the screw node 21 has the lower limit pitch, the rear spiral surface 50b of the thread 50 is in contact with the spiral surface A2 of the screw node 21, and the front spiral surface 50a is the front end. Only in contact with the screw node 21.
As shown in FIG. 13, when the screw node 21 is at the upper limit pitch, the front spiral surface 50a of the screw thread 50 is in contact with the spiral surface B1 of the screw node 21, and the rear spiral surface 50b is only at the front end thereof. To touch.

  As shown in FIG. 11, when the screw node 21 is at a standard pitch, both the front spiral surface 50a and the rear spiral surface 50b of the screw thread 50 substantially contact the screw node 21 only at the front end thereof.

  In the fourth embodiment, since the pitch error of the screw joint 21 is set smaller than that of the first embodiment, there is no difference in the width of the screw threads 50. However, if the pitch error of the pitch joint 21 is the same, The width of the thread 50 in the front end side region Rf and the rear end side region Rr of the fourth embodiment is narrower than the one end side region Re of the first embodiment.

14A and 14B show the fifth and sixth embodiments. In FIG. 14, in order to clarify the difference from the fourth embodiment, the vertical dimension is halved as compared with FIGS. 10 to 13.
In the fifth embodiment shown in FIG. 14A, the front spiral surface 50a is retracted from the spiral surfaces A1 and B1, and the rear spiral surface 50b is retracted from the spiral surfaces A2 and B2, thereby causing the front end region Rf and the rear The thread width of the end region Rr is made constant, and the width of the transition region Rs between them is gradually narrowed toward the rear end. A line connecting the centers of the threads 50 coincides with the reference spiral L having a standard pitch.

  In the sixth embodiment shown in FIG. 14B, the front spiral region 50a is retracted from the spiral surface B1 with the rear spiral surface 50b coinciding with the spiral surface A2, so that the front end region Rf and the rear end region The thread width of Rr was made constant.

  Contrary to the sixth embodiment, the front end side region Rf and the rear end side region Rr are obtained by retracting the rear side spiral surface 50b from the spiral surface A2 while keeping the front side spiral surface 50a coincident with the spiral surface B1. The thread widths of each may be constant.

  Furthermore, the spiral surfaces 50a and 50b may be configured to draw a line between the most receding line in FIG. 14A and the most swollen line in FIG. 10, or the most receding in FIG. 14B. You may comprise so that the line between this line and the most swollen line of FIG. 10 may be drawn.

  Contrary to the fourth embodiment, the thread width of the rear end region Rr can be maximized and the thread width of the front end region Rf can be minimized.

  In the above embodiment, the clearance between the screw thread 50 and the screw node 21 is set to zero within the error range, but it is needless to say that a predetermined clearance may be set. When setting such a predetermined clearance, in each embodiment, if one of the front spiral surface 50a and the rear spiral surface 50b is made closer to the other in the axial direction of the female screw portion by the predetermined clearance. Good.

  When the predetermined clearance is set as described above, when a large tensile load is applied to the screw rebar 20 in a state where the fixing metal member 10 is fixed to the screw rebar 20 by grout filling, the screw rebar 20 of the fixing metal member 10 is set. The relative movement amount can be limited to the predetermined clearance level at the maximum.

The present invention is not limited to the above embodiment, and various forms can be adopted. For example, the annular groove 15 may not be provided in the screw alloy of the present invention.
The screw alloy of the present invention may be a fixing metal used in a portion other than the joint portion. The flange portion of the fixing hardware may be provided not in the end of the cylindrical portion but in the intermediate portion in the axial direction.
In addition, the screw alloy of the present invention may be a joint that connects two screw rebars. In this case, the present invention is applied on the assumption that the female thread portion of the joint has two female thread portions substantially for each screw rebar.
Furthermore, the screw alloy of the present invention may be a joint that connects one screw rebar and another deformed rebar (including a screw rebar). In this case, one side of the joint serves as a female thread portion to which the present invention can be applied, and the other side serves as a housing space for inserting the deformed reinforcing bar and filling the grout material.

FIG. 3 is an enlarged longitudinal sectional view of a fixing hardware constituting the first embodiment of the present invention. It is a principal part expanded vertical sectional view which shows the state which screwed the fixing metal fitting to the screw reinforcement. It is an expanded view which shows the screw thread shape of the internal thread part of the same fixing metal. It is an expanded view which shows the state which screwed the fixing metal fitting to the screw rebar which has a screw node of a standard pitch. It is an expanded view which shows the state which screwed the fixing metal fitting to the screw rebar which has a screw node of a minimum pitch. It is an expanded view which shows the state which screwed the fixing metal fitting to the screw rebar which has a screw node of an upper limit pitch. It is an expanded view which shows the thread shape of the internal thread part of the fixing metal | metal | money compared with a conventional shape. It is an expanded view which shows the screw thread shape of the internal thread part of the fixing metal object which makes 2nd Embodiment of this invention. It is an expanded view which shows the screw thread shape of the internal thread part of the fixing metal fixture which makes 3rd Embodiment of this invention. It is an expanded view which shows the screw thread shape of the internal thread part of the fixing metal object which makes 4th Embodiment of this invention. It is an expanded view which shows the state which screwed the fixing metal fitting of 4th Embodiment to the screw rebar which has a screw node of a standard pitch. It is an expanded view which shows the state which screwed the fixing metal fitting of 4th Embodiment to the screw rebar which has a screw node of a minimum pitch. It is an expanded view which shows the state which screwed the fixing metal fitting of 4th Embodiment to the screw reinforcement which has a screw node of an upper limit pitch. (A), (B) is an expanded view which respectively shows the thread form of the internal thread part of the fixing metal fitting of 5th, 6th embodiment. It is a principal part expanded vertical sectional view which shows the conventional fixing metal fitting and the screwed state of a screw reinforcement.

Explanation of symbols

10 Fixing hardware (screw alloy for screw rebar)
14 Female thread portion 20 Screw rebar 21 Screw joint 50 Screw thread 50a Front spiral surface (spiral surface facing one side)
50b Rear spiral surface (spiral surface facing the other side)
51-54 1st-4th spiral surface part Rm Central area | region (intermediate area | region)
Re Near-end region Rs Transition region Rf Near-end region (near-end region)
Rr Area near the rear end (area near the other end)

Claims (10)

In a screw alloy that is fixed to a screw rebar by having a female screw portion and screwing a screw rebar into the female screw portion and filling a filler between the inner periphery of the female screw portion and the outer periphery of the screw rebar. ,
The thread width of the female thread part changes along the spiral of the thread, the thread width in the middle area of the female thread part is the widest, and the thread width in the vicinity of both ends of the female thread part is the narrowest A screw alloy for screw rebar.   2. The screw alloy for threaded rebar according to claim 1, wherein the thread width gradually decreases from an intermediate region of the female screw portion toward both ends. The thread of the female screw portion has a spiral surface facing one side in the axial direction of the female screw portion and a spiral surface facing the other side,
The spiral surface facing the one side has a first spiral surface portion located in a region on one side in the axial direction of the female screw portion and a second spiral surface portion located in a region on the other side of the female screw portion,
The spiral surface facing the other side has a third spiral surface portion located in the one side region and a fourth spiral surface portion located in the region on the other side,
The lead angles of the first and fourth spiral surface portions are constant and equal to each other, the lead angles of the second and third spiral surface portions are constant and equal to each other, and the lead angles of the first and fourth spiral surface portions are The screw alloy for threaded reinforcing bars according to claim 2, which is different.   The screw alloy for a screw rebar according to claim 1, wherein the thread width in the intermediate region of the female thread portion is constant, and the thread width in the region near both ends is constant.   The female screw portion has a transition region in which the thread width decreases toward a region near both ends between the intermediate region where the thread width is constant and a region near both ends. 4. A threaded alloy for screw rebars according to 4. In a screw alloy that is fixed to a screw rebar by having a female screw portion and screwing a screw rebar into the female screw portion and filling a filler between the inner periphery of the female screw portion and the outer periphery of the screw rebar. ,
The thread width of the female thread portion changes along the spiral of the thread, the thread width in the region near one end of the female screw portion is the widest, and the thread width in the region near the other end is narrowest Threaded alloy for screw rebar.   The screw alloy for a screw rebar according to claim 6, wherein the thread width of the female thread portion gradually decreases from one end to the other end. The female screw portion has a spiral surface facing one side in the axial direction and a spiral surface facing the other side,
The screw alloy for a screw rebar according to claim 5, wherein the lead angle of the spiral surface facing the one side and the spiral surface facing the other side is constant and different from each other.   The screw alloy for a screw rebar according to claim 6, wherein the thread width in the region near one end is constant and the thread width in the region near the other end is constant.   The female thread portion has a transition region where the thread width decreases from the one end vicinity region to the other end vicinity region between the one end vicinity region and the other end vicinity region where the thread width is constant. The screw alloy for threaded reinforcing bars according to claim 9, wherein

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