Joint structure

Abstract

To provide means that can easily position and securely fix a cylindrical body to a desired axial position of a rod-shaped body and is made to improve connectivity between rod-shaped bodies and improve drawing strength and push-in strength.SOLUTION: A joint structure has an insertion hole that can insert a rod-shaped body along an axial direction and connects the rod-shaped body by engaging an inner periphery to rod-shaped body ribs. The inner periphery comprises: engaging protrusions that are arranged along the axial direction and may be engaged with the ribs; at least one or more kinds of concave parts that alternate to the engaging protrusions towards the axial direction and are recessed so as to be able to fit the ribs; and large diameter surfaces that are adjacent to the engaging protrusions and the concave parts in a circumferential direction and do not engage with the ribs. The joint structure restricts the axial direction displacement of the rod-shaped body by fitting the ribs to the concave parts.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a joint structure.

Background Art

[0002] Conventionally, when constructing a structure made of reinforced concrete, it is necessary to make the reinforcing bars embedded in the concrete long. However, the length of the reinforcing bars is restricted due to transportation constraints, etc., and they were joined on-site to make them longer. A joint is used for joining the reinforcing bars, and the reinforcing bars are connected by inserting the reinforcing bars into the openings at both ends of the joint (see, for example, Patent Document 1). As the reinforcing bars, threaded bars, deformed steel bars having longitudinal ribs and transverse ribs (see, for example, Patent Document 2), deformed reinforcing bars in which a large number of ridges parallel to each other in the longitudinal direction are arranged at substantially equal intervals over the entire axial length of the reinforcing bar on a part of the outer peripheral surface of a reinforcing bar having a substantially circular cross section (see, for example, Patent Document 3), etc. are used. In addition, as a known frame rack, one including four columns (rod-shaped bodies), a plurality of sleeves, and a plurality of shelf boards is known. A plurality of fitting grooves are formed at various height positions on the columns. The outer edge of the sleeve has a tapered shape and can sandwich the column, and has a convex edge that can be fitted to the fitting groove. Further, at the corner positions of the shelf board, a fitting portion as a joint having a cylindrical shape is provided, and a tapered fitting through hole is formed in the fitting portion. Such a frame rack fixes the shelf board to four columns installed perpendicular to the ground. The convex edge of the sleeve is fitted into a fitting groove at an appropriate height for positioning, and the sleeve is fitted into the fitting through hole of the fitting portion to position the shelf board.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] For the joint described in the above-mentioned Patent Document 1, since it is necessary to fill the inside of the reinforcing bar housing portion in which the reinforcing bars are loosely fitted with grout, operations such as grout transportation and kneading at the construction site are generated, and the work burden becomes large. In addition, although grout is filled from the injection holes provided at the central portion in the longitudinal direction of the joint with the reinforcing bars loosely fitted in the reinforcing bar housing portion, grout leaks from the openings at both ends in the longitudinal direction of the joint during filling and cannot be filled to the full, so nuts need to be tightened at both ends of the joint to block the openings at both ends of the joint. Due to these matters, there are many problems such as an increase in the number of required parts and the labor of work, and it takes a lot of labor to align the axes of the two reinforcing bars inserted into the joint.

[0005] In addition, rod-shaped bodies such as deformed steel bars described in the above-mentioned Patent Document 2 and deformed reinforcing bars described in Patent Document 3 are said to have difficulty in adhering to concrete during concrete embedding compared with threaded reinforcing bars and the like.

[0006] In addition, the fitting portion used for a known frame rack is fixed to the column by interposing a sleeve, so the number of parts increases. In addition, the sleeve may crack after a certain period of use. If a crack occurs in the sleeve, the shelf board will fall, so there is a problem of lack of safety.

[0007] The present invention has been made by the intensive research of the inventor in view of the above problems, and by a simple structure, it is possible to easily position and fix a cylindrical body at a desired axial position of a rod-shaped body, improve the connectivity between rod-shaped bodies, and provide a means for improving the pull-out strength in the embedded state with respect to a solidifying fluid such as concrete, mortar, and resin.

Means for Solving the Problems

[0008] The joint structure of the present invention In one aspect has an insertion hole through which a rod-shaped body can be inserted along the axial direction, and is a joint structure for connecting the rod-shaped body by engaging the inner circumference with the rib of the rod-shaped body. On the inner circumference, there are engagement convex portions arranged in a row in the axial direction and capable of engaging with the rib, and at least one or more types of forming a non-helical shape concave portions recessed axially alternating with the engagement convex portions and capable of fitting the rib, and a large-diameter surface adjacent to the engagement convex portions and the concave portions in the circumferential direction and not engaging with the rib. The concave portion has a hybrid structure in which the non-helical shape forms a symmetric shape and an asymmetric shape with the axial direction as the axis of symmetry in a radial view, and is arranged in the axial direction, and the symmetric shape and the asymmetric shape are arranged. It is characterized in that the rib is fitted into the concave portion to restrict the axial displacement of the rod-shaped body. The joint structure according to another aspect of the present invention is a joint structure having an insertion hole through which a rod-shaped body can be inserted along the axial direction, and connecting the rod-shaped body by engaging the inner circumference with a rib of the rod-shaped body. On the inner circumference, there are provided engaging convex portions arranged in the axial direction and capable of engaging with the rib, and at least one or more concave portions arranged alternately with the engaging convex portions in the axial direction and recessed so as to be able to fit the rib. It has a large-diameter surface that is circumferentially adjacent to the engaging convex portion and the concave portion and is not engaged with the rib. The insertion hole has a substantially oval or substantially elliptical hole shape in an axial view. The rib is fitted into the concave portion to restrict the axial displacement of the rod-shaped body.

[0011] Further, in the joint structure of the present invention, the symmetric shape has closed ends at both circumferential ends, and the main body of the joint structure has an expansion portion capable of expanding the internal space. The expansion portion can transition between a state in which the rib is received by the inner circumference and a process state in which the insertion hole is expanded to receive the rib by the inner circumference.

[0012] Further, the joint structure of the present invention is characterized in that the expansion portion has an elastic deformation mechanism and / or a radial separation mechanism.

[0013] Further, the joint structure of the present invention is characterized in that the concave portion having the asymmetric shape has an open end at one circumferential end and can receive the rib from the open end side.

[0014] Further, the joint structure of the present invention is characterized in that the concave portion having the asymmetric shape has a closed end at the other circumferential end and can restrict the circumferential displacement of the rib by the closed end.

[0015] Further, the joint structure of the present invention is characterized in that the concave portion forms a spiral shape, and the radial end portion of the engagement convex portion forms a planar shape, a convex curved surface shape, or an acute angle shape.

[0016] In addition, the joint structure of the present invention is characterized in that the concave portion having a spiral shape is formed continuously or intermittently along a virtual spiral path.

[0017] In addition, the joint structure of the present invention is characterized in that the concave portion having a spiral shape is formed continuously, and is configured such that the width of the concave portion gradually or stepwise decreases from one axial end to the middle portion.

[0018] In addition, the joint structure of the present invention is characterized in that the insertion hole has a hole shape that is substantially similar or approximate to the outer shape of the rod-shaped body in the axial direction view.

[0020] In addition, the joint structure of the present invention is characterized in that the insertion hole has two-width portions, and the inner peripheral surface is formed by an arc that forms a convex shape with a predetermined radius of curvature connecting between opposite ends of the opposing two-width portions.

[0021] In addition, the joint structure of the present invention is characterized in that the insertion hole has different cross-sectional areas in a first range in the middle portion from one axial end and a second range in the middle portion from the other axial end.

[0022] In addition, the joint structure of the present invention is characterized in that the concave portion from one axial end to the middle portion has a spiral shape, and the concave portion from the other end to the middle portion has a non-spiral shape.

[0023] In addition, the joint structure of the present invention is characterized in that a relative rotation prevention member for preventing relative rotation with the rod-shaped body is provided at least at one axial end.

[0024] In addition, the joint structure of the present invention is characterized in that a relative displacement prevention member for preventing relative displacement in the axial direction with the rod-shaped body is provided at least at one axial end.

[0025] In addition, the joint structure of the present invention is provided with a rigid connection structure at the axial end, and the rigid connection structure has a relative rotation prevention member for preventing relative rotation with the rod-shaped body and a relative displacement prevention member for preventing relative displacement with respect to the rod-shaped body.

[0026] In addition, the joint structure of the present invention is characterized in that the relative rotation prevention member surrounds the rod-shaped body and is inserted into the engagement hole.

[0027] In addition, the joint structure of the present invention has an engagement surface where the relative rotation prevention member engages with the inner periphery of the engagement hole, and a non-circular rod-shaped body insertion hole that substantially corresponds to the outer shape of the rod-shaped body in an axial view, and the rod-shaped body can be fitted into the rod-shaped body insertion hole in a state where relative rotation is impossible, and the engagement surface engages with the inner periphery of the engagement hole.

[0028] In addition, the joint structure of the present invention is characterized in that the relative displacement prevention member engages with a rib of the rod-shaped body, and axial displacement is restricted.

[0029] In addition, the joint structure of the present invention is characterized in that the relative displacement prevention member has a hole portion through which the rod-shaped body can be inserted and has a spiral groove on the inner peripheral surface.

[0030] In addition, the joint structure of the present invention is characterized in that a relative rotation prevention mechanism for preventing relative rotation between the relative rotation prevention member and the relative displacement prevention member is provided at the contact portion between the relative rotation prevention member and the relative displacement prevention member.

[0031] In addition, the joint structure of the present invention is characterized in that at an appropriate intermediate position in the longitudinal direction of the main body, there is a confirmation hole that penetrates both inside and outside to make the insertion depth of the rod-shaped body visible.

[0032] In addition, the joint structure of the present invention is characterized in that the confirmation hole has a central position suggesting means indicating the central portion in the longitudinal direction.

[0033] In addition, the joint structure of the present invention is characterized in that the confirmation hole has a constricted portion where the hole shape is constricted at a location corresponding to the central portion in the longitudinal direction, and the constricted portion forms the central position suggesting means.

[0034] Further, the joint structure of the present invention is characterized in that the confirmation hole is closed by a member having light transmissibility.

Advantages of the Invention

[0035] According to the present invention, with a simple structure, it is possible to easily position and fix the cylindrical body at a desired axial position of the rod-shaped body, improve the connectivity between the rod-shaped bodies, and improve the pull-out strength in the embedded state with respect to solidifying fluids such as concrete, mortar, and resin.

Brief Description of the Drawings

[0036]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

Figure 26

Figure 27

Figure 28

MODE FOR CARRYING OUT THE INVENTION

[0037] An embodiment of a joint structure for connecting rod-shaped bodies (steel bars for embedding in a hydraulic solidified body) of the present invention will be described with reference to the drawings. The joint structure is constituted by a member that forms a cylindrical member as a whole, is connected to a rod-shaped body inserted into an end portion, and connects the rod-shaped bodies by inserting the rod-shaped bodies into both end portions. Therefore, the joint structure has a structure for engaging with the rod-shaped body and the like.

[0038] FIG. 1 shows the rod-shaped body 1 of the present embodiment, where (a) is a front view and (b) is a cross-sectional view taken along line A-A. FIG. 2 is a side view showing the rib 4 of the rod-shaped body 1 of the present embodiment. The rod-shaped body 1 is, for example, a long member such as a substantially deformed steel bar or a reinforcing bar as a reinforcing steel bar. The rod-shaped body 1 has a reduced-diameter surface 2 existing in two predetermined regions facing each other across the axis, ribs 4 arranged in the axial direction and protruding radially outward, and a recessed-diameter surface 6 recessed alternately with respect to the ribs 4 in the axial direction. Note that the rod-shaped body 1 can be constituted by an appropriate material such as a steel material. The reduced-diameter surface 2 extends in the axial direction and is formed such that the radius from the axis gradually decreases toward the central portion in the circumferential direction of the region. The reduced-diameter surface 2 can have, for example, a two-sided width formed on the rod-shaped body 1.

[0039] The recessed-diameter surface 6 is set such that the distance from the axis is within the range of the distance from the axis in the reduced-diameter surface 2. For example, the recessed-diameter surface 6 can set the distance from the axis so as to be a distance corresponding to the radius at the central portion or both end portions in the circumferential direction of the reduced-diameter surface 2.

[0040] As shown in FIG. 2, the rib 4 has a tip portion 10 at the radially outer end. The ridge line 12 forming the tip portion 10 extends in a direction perpendicular to the axis, and both ends along the circumferential direction extend toward the reduced-diameter surface 2. Further, the rib 4 has four surfaces 14a to 14d facing in different normal directions. Further, these four surfaces 14a to 14d are provided along a virtual helical surface assumed around the axis of the rod-shaped body 1.

[0041] The four surfaces 14a to 14d form a substantially quadrangular pyramid shape when the outer peripheral surface of the rod-shaped body 1 is developed on a virtual plane (developed state). Here, among the four surfaces 14a to 14d, the upper left in the direction shown in FIG. 2 is the surface 14a, the lower left is the surface 14b, the upper right is the surface 14c, and the lower right is the surface 14d.

[0042] The ridge line 12 that forms the boundary between the surface 14a and the surface 14b and between the surface 14c and the surface 14d extends in a direction perpendicular to the axis, and both ends face the reduced-diameter surface 2. Further, the surfaces 14a to 14d have a shape that is reduced in the axial direction of the rod-shaped body 1 toward the circumferential end portion located on the reduced-diameter surface 2 side, that is, a shape with a reduced width. Therefore, the rib 4 forms a tip portion 10 with a sharp circumferential end.

[0043] Note that the tip portion 10 may have a substantially acute-angled, substantially obtuse-angled, or substantially arc-shaped cross-sectional shape, or may be a slightly flat surface shape. However, preferably, if it is a slightly arc-shaped, it is easy to manufacture, difficult to be damaged, and in addition, as will be described later, the fitting property with the joint structure can be improved.

[0044] Further, the rib 4 and the reduced-diameter surface 6 are provided in two regions facing each other across the axis, and the axial positions of the ribs 4 and the reduced-diameter surfaces 6 in each region are set to be stepped. That is, the reduced-diameter surface 6 of the other region is arranged at the position of the rib 4 in one region across the axis. Also, the rib 4 of the other region is arranged at the position of the reduced-diameter surface 6 in one region. Of course, the axial positions of the rib 4 and the reduced-diameter surface 6 may be set to coincide with each other.

[0045] Further, the rib 4 protrudes most radially outward at the central portion, and the radially protruding length gradually decreases toward the circumferential end portion. That is, the ridge line 12 of the rib 4 is arranged inside the virtual circle C having a radius from the axis of the rod-shaped body 1 shown in FIG. 1(b) to the point where the protruding length of the rib 4 is the longest. Also, the rib 4 has a circumferential end connected to the reduced-diameter surface 2 and has an end surface 4a flush with the reduced-diameter surface 2.

[0046] The connection between the reduced-diameter surface 2 of the rib 4 and the rib 4 may be made, for example, by setting the ridge line 12 in the shape of a curve 13a at the circumferential end of the rib 4 as shown in Fig. 3(a), or by setting the ridge line 12 in the shape of a straight line 13b at the circumferential end of the rib 4 as shown in Fig. 3(b).

[0047] Fig. 4 shows another shape of the rib 4, where (a) is a side view, (b) is a front view, and (c) is a cross-sectional view taken along line B-B of (a). The rib 4 may be set such that the radial protrusion length at the circumferential end is substantially zero as shown in Fig. 4. At this time, the rib 4 is set such that the protrusion length gradually decreases at a substantially constant rate. Of course, the protrusion length of the rib 4 is not limited to a shape that gradually decreases along the circumferential direction. It may have a substantially constant shape in a predetermined region extending from the central part to the circumferential end. However, the ridge line 12 is set in the shape of the curve 13a or the straight line 13b at the circumferential end and connected to the reduced-diameter surface 2.

[0048] Also, the tip of the rib 4 may have a substantially triangular pyramid shape with a cubic curved surface, where the two circumferential end portions are each smaller than the curved and slender triangular pyramid space region surrounded by the virtual extension surfaces formed by extending the four surfaces 14a to 14d in the rotational direction around the axis. That is, the two circumferential end portions of the rib 4 may form a cubic curved surface with a gradually decreasing protrusion length in the direction perpendicular to the axis so as to be located radially inside the surfaces 14a to 14d. Also, this cubic curved surface may form a substantially triangular pyramid shape, but of course, it may also be a curved surface shape. Also, the rib 4 may have a shape where the two end portions are not connected to the reduced-diameter surface 2, that is, it may have a length that can be circumferentially spaced from the reduced-diameter surface 2.

[0049] Here, Fig. 28 shows another example of the shape of rib 4, where (a) is a perspective view, (b) is a plan view, and (c) is a side view. The rib 4 having a cubic surface with a gradually decreasing protruding height in the axis-orthogonal direction may have a boundary portion 151 between the rib locking portion 150 at the central portion and the tip portion 152 in the circumferential direction shown in Fig. 28. Further, the rib 4 is set to a shape in which the height protruding in the radial direction is the highest at the central portion and gradually decreases toward the tip portion 152 and approaches approximately zero at the location closest to the reduced diameter surface 2.

[0050] Specifically, the rib 4 has a shape that is inclined in a substantially mountain shape along the circumferential direction such that the protruding height gradually decreases from the central portion of the rib locking portion 150 toward the tip portion 152, and the inclination on the tip portion 152 side from the boundary portion 151 has a steeper gradient than the inclination in the rib locking portion 150. Further, the rib locking portion 150 is axially engaged with a concave portion 26 described later, and the reduction of the protruding height is set to be gentler compared to the tip portion 152 in order to maintain the shear strength of the rib 4.

[0051] As described above, bar-shaped bodies such as deformed steel bars described in Patent Document 2 and deformed reinforcing bars described in Patent Document 3 have a problem that the concrete adhesion is poor when embedded in concrete compared to screw-threaded reinforcing bars and the like. However, by adopting a shape having four surfaces 14a to 14d like the rib 4 or a shape having the rib locking portion 150 and the tip portion 152 shown in Fig. 28, the concrete adhesion can be improved, and the rib 4 can be easily screwed into a joint structure 20 described later.

[0052] Further, it may be possible to set a large protruding height of the rib 4 in order to improve the pull-out strength during concrete embedding. However, if the protruding height of the rib 4 is increased, the rib 4 can extend to the reduced diameter surface 2, and the rib 4 can protrude radially outside the reduced diameter surface 2 at a position adjacent to the reduced diameter surface 2. Therefore, in order to form the reduced diameter surface 2, processing such as cutting the rib 4 is required. On the other hand, for the rib 4 having the shape shown in Fig. 28, by making the gradients of the inclinations different between the rib locking portion 150 and the tip portion 152 between the boundary portions 151, it is possible to improve the mass productivity while maintaining the pull-out strength. Therefore, in the case of the rod-shaped body 1 having the rib 4 including the rib locking portion 150 and the tip portion 152, the intended shape can be continuously formed with high precision when mass-producing the rod-shaped body 1. Further, since the rib 4 has the tip portion 10 (152), it becomes easy to fit into the concave portion 26 of the joint structure 20 described later, and the connectivity can be improved.

[0053] Next, the joint structure 20 will be described. The joint structure 20 is not limited to a joint that connects two rod-shaped bodies 1, and is a concept including a fixing nut fixed to the end of a bar-shaped body 1 like a reinforcing bar, a shelf support fitting fixed in the middle of the bar-shaped body 1, etc., and has an inner peripheral shape that penetrates in the axial direction and has both ends open and can surround the rod-shaped body 1.

[0054] FIG. 5 shows the joint structure 20 of the present embodiment, (a) is a plan view, and (b) is a cross-sectional view. The joint structure 20 has an inner peripheral surface that surrounds the rod-shaped body 1. On the inner peripheral surface, a large-diameter surface 22 arranged at positions opposite to each other across the axis, an engaging convex portion 24 and a concave portion 26 adjacent to the large-diameter surface 22 in the circumferential direction are arranged.

[0055] The large-diameter surface 22 is set so that the distance from the axis is substantially equidistant and is located radially outside the rib 4 when surrounding the rod-shaped body 1. That is, a radius larger than that of the rib 4 is set so as to be in a substantially non-contact state with the rib 4. Note that the large-diameter surface 22 is not limited to having a substantially equidistant distance from the axis, and may be set so that the distance from the axis changes along the circumferential direction as long as it is at least in a non-contact state with the rib 4.

[0056] The engaging convex portion 24 protrudes radially inward from the large-diameter surface 22 and extends in the circumferential direction, and is provided in a plurality of rows in the axial direction. Further, the engaging convex portion 24 is set so that the distance from the axis is located radially outside the reduced-diameter surface 2 when surrounding the rod-shaped body 1.

[0057] The concave portion 26 is a depression having a concave shape relative to the engaging convex portion 24, and is arranged alternately with the engaging convex portion 24 in the axial direction. The depth of the concave portion 26 is set such that the bottom is arranged at least radially outside the rib 4 at a predetermined relative position. That is, the depth of the concave portion 26 may be set so that the distances from the axis are substantially equal, and the concave portion 26 may be continuously provided so as to form a substantially continuous surface with the large-diameter surface 2. Of course, the depth of the concave portion 26 may be set so that the distance from the axis is longer than that of the large-diameter surface 22.

[0058] In addition, the concave portion 26 has an asymmetric shape with respect to the symmetry axis parallel to the axial direction in the radial direction view. That is, one end in the circumferential direction (the left end in FIG. 5(b)) becomes an open end 28 with a widened width, gradually narrows toward the other end (the right end in FIG. 5(b)), and the other end becomes a closed end that restricts the circumferential displacement of the rib 4. Here, a wall-shaped stopper 29 protruding radially from the bottom surface of the concave portion 26 is provided on the other end side to form the closed end. Further, the protruding length in the radial direction of the stopper 29 is set so as to restrict at least the circumferential displacement of the rib 4.

[0059] In addition, the engaging convex portion 24 and the concave portion 26 are arranged in two regions facing each other across the axis so as to correspond to the rib 4 and the concave-diameter surface 6 of the rod-shaped body 1, and the engaging convex portions 24 in one region and the engaging convex portions 24 in the other region are set so that their axial positions are staggered from each other. Of course, the engaging convex portion 24 and the concave portion 26 may be provided with the engaging convex portion 24 at the opposing position of the engaging convex portion 24 and the concave portion 26 at the opposing position so that their axial positions do not become staggered from each other, corresponding to the setting of the rod-shaped body 1 in which the ribs 4 are provided at the same position in the axial direction.

[0060] Here, FIG. 6 is a cross-sectional view showing the joint structure 20, showing the positional relationship between the engaging convex portion 24 and the concave portion 26 in two regions facing each other at a distance in the radial direction. As shown in FIG. 6, a concave portion 26 is arranged in the other region located on the right side with respect to the engaging convex portion 24 in one region located on the left side, and an engaging convex portion 24 is arranged in the other region with respect to the concave portion 26 in one region.

[0061] Therefore, similar to the ribs 4 and the concave diameter surface 6 of the rod-shaped body 1, by staggering the engaging convex portions 24 and the concave portions 26, the ribs 4 of the rod-shaped body 1 can be fitted into the respective concave portions 26. In the case where the rod-shaped body 1 has a shape in which the axial positions of the ribs 4 and the concave diameter surface 6 are aligned in two regions facing each other across the axis, the axial positions of the engaging convex portions 24 and the concave portions 26 shall be aligned.

[0062] Next, a procedure for connecting the rod-shaped body 1 and the joint structure 20 will be described. First, insert the rod-shaped body 1 into the insertion hole of the joint structure 20. At this time, align the reduced-diameter surface 2 of the rod-shaped body 1 with the position facing the engaging convex portion 24 and the concave portion 26 of the joint structure 20. At this time, the rod-shaped body 1 can be inserted along the axial direction without contacting the joint structure 20. That is, since the reduced-diameter surface 2 is radially inside the engaging convex portion 24 and the rib 4 is radially inside the large-diameter surface 22, the rod-shaped body 1 can be inserted while avoiding contact with the joint structure 20 and can be displaced in the axial direction.

[0063] After inserting the rod-shaped body 1, rotate the joint structure 20 relative to the rod-shaped body 1 in the circumferential direction to fix the rod-shaped body 1 to the joint structure 20. Here, FIG. 7 schematically shows the entry of the rib 4 into the concave portion 26, where (a) is a diagram showing the position before entering the concave portion 26, and (b) is a diagram showing the position when fitted into the concave portion 26. Note that FIG. 7 shows the inner peripheral surface of the cylindrical body 20 on the front side. Since the surfaces 14a to 14d of the rib 4 face the concave portion 26, the rod-shaped body 1 (not shown) is located on the front side of the paper surface, and the ridge line 12 of the rib 4 is shown by a dotted line, showing a state where the surfaces 14a to 14d face the concave portion 26 toward the back side of the paper surface.

[0064] The joint structure 20 rotates relative to the rod-shaped body 1 in a predetermined rotational direction so that the rib 4 shown in FIG. 7(a) enters from the open end 28 into the concave portion 26. Also, the joint structure 20 is rotated relative to the rod-shaped body 1 until the rib 4 shown in FIG. 7(b) is fitted into the concave portion 26 and the leading end portion in the advancing direction of the rib 4 abuts against the closed end of the concave portion 26.

[0065] When the rib 4 enters between the engaging convex portions 24, the axial displacement of the rod-shaped body 1 with respect to the joint structure 20 is restricted. That is, with respect to the joint structure 20, the relative displacement between the joint structure 20 and the rod-shaped body 1 is restricted in both the pulling-out direction and the pushing-in direction of the rod-shaped body 1. Further, when the rib 4 abuts against the closed end, the circumferential displacement of the rod-shaped body 1 along a predetermined rotational direction is restricted. Therefore, the rod-shaped body 1 is connected and fixed to the joint structure 20.

[0066] Note that the rib 4 of the rod-shaped body 1 has a sharp tip portion 10, and the open end 28 of the concave portion 26 of the joint structure 20 is widened. Therefore, when the joint structure 20 is rotated, the engaging convex portion 24 is prevented from being caught by the rib 4, and the rib 4 can be easily fitted into the concave portion 26.

[0067] Also, if the tip portion 10 of the rib 4 is further sharpened as shown in FIG. 4, it becomes easier to fit the rib 4 into the concave portion 26 without being caught, which is preferable. Further, as long as the engaging convex portion 24 has a surface at the circumferential end portion, even if the tip portion 10 is sharpened, the rib 4 and the engaging convex portion 24 may come into contact, and the relative rotation of the joint structure 20 with respect to the rod-shaped body 1 may be restricted. Therefore, as shown in FIG. 8(a), it is preferable to form an inviting shape in which the open end 28 is further widened, that is, greatly expanded in the axial direction, and the circumferential end portion of the engaging convex portion 24 is sharpened. Further, as shown in FIG. 8(b), it is more preferable that the tip portion 10 and the circumferential end portion of the engaging convex portion 24 are each formed in a sharp shape. As a result, the ends do not come into contact with each other, and the rib 4 is more easily guided automatically into the concave portion 26, making it easier to fit, and the connection between the rod-shaped body 1 and the joint structure 20 can be easily performed.

[0068] Note that the joint structure 20 is connected to the rod-shaped body 1 by relative rotation. However, since the open end 28 is formed in the concave portion 26, the joint structure 20 can rotate in the reverse direction. If the joint structure 20 rotates in the reverse direction, the connection between the rod-shaped body 1 and the joint structure 20 will be released. Therefore, an anti-backward rotation structure may be provided between the rod-shaped body 1 and the joint structure 20. For example, an anti-backward rotation structure can be formed by changing the shape of the concave portion with respect to the rib 4. Here, FIG. 9 is a radial view showing another example of the inner peripheral shape of the joint structure 20. For example, the axial length (width) of the concave portion 30 is reduced on the open end 32 side, that is, the open end 32 of the concave portion 30 is made narrower than the middle portion to form an anti-backward rotation structure.

[0069] In that case, the width of the open end 32 is set to be smaller than the maximum width of the rib 4 (the width at the circumferential center portion). Note that the difference between the width of the open end 32 and the maximum width of the rib 4 is set to such an extent that the rib 4 and / or the engaging convex portion 24 can be elastically deformed and the rib 4 can enter the concave portion 30.

[0070] FIG. 10 schematically shows the entry of the rib 4 into the concave portion 30. (a) is a view showing the position before entry into the concave portion 30, and (b) is a view showing the position when fitted into the concave portion 30. In FIG. 10, the approximate positions of the surfaces 14a and 14b existing on the back side of the paper surface are indicated by the corresponding symbols to the dotted lines. As shown in FIG. 10(a), the surfaces 14a and 14b of the rib 4 abut against the engaging convex portion 24 on the open end 32 side of the concave portion 30, but by pushing in against the resistance, the surfaces 14a and 14b and / or the engaging convex portion 24 are elastically deformed, and the rib 4 is made to enter the concave portion 30 as shown in FIG. 10(b).

[0071] By fitting the rib 4 into the concave portion 30 in this way, even when a torque or the like in the direction opposite to the rotation direction when the joint structure 20 is connected to the rod-shaped body 1 acts, in order for the rib 4 to come out of the concave portion 30, it is necessary to apply a torque of such a magnitude as to elastically deform the surfaces 14c and 14d and / or the engaging convex portion 24. As a result, an anti-backward rotation structure is formed.

[0072] Further, the reverse rotation prevention structure may be formed by a member separate from the rod-shaped body 1 and the joint structure 20. For example, when the rod-shaped body 1 is fixed to the joint structure 20, the reduced-diameter surface 2 of the rod-shaped body 1 faces the large-diameter surface 22 of the joint structure 20, and a gap is formed between the reduced-diameter surface 2 and the large-diameter surface 22. Therefore, as shown in FIG. 11, a plate-shaped body having an irregular outer shape with holes may be used, and the gap between the reduced-diameter surface 2 and the large-diameter surface 22 may be filled by a rotation prevention member 40 having a spacer portion 42 erected in a direction substantially orthogonal to the plate surface around the hole 44.

[0073] Specifically, with the tip of the spacer portion 42 facing the joint structure 20, the rod-shaped body 1 is inserted through the hole 44, and the rotation prevention member 40 is brought into contact with or close to the end surface of the joint structure 20 so that the spacer portion 42 is inserted between the reduced-diameter surface 2 and the large-diameter surface 22 to fill the gap. Thereby, even if an attempt is made to rotate the joint structure 20 so that the rib 4 can be displaced relatively in a direction to retreat from the concave portion 30, the relative displacement of the rib 4 can be restricted by the spacer portion 42, that is, the rotation of the joint structure 20 can be restricted.

[0074] When disposing the rotation prevention member 40, for example, a nut may be screwed onto the rod-shaped body 1 at a position facing the joint structure 20 with the rotation prevention member 40 interposed therebetween to prevent the spacer portion 42 from coming off. Further, the spacer portion 42 may be in a so-called wedge shape thickened from the base end side toward the tip end side, or the outer surface of the erected surface may be uneven to improve the engagement property. In this case, a corresponding uneven shape may also be provided on the large-diameter surface of the joint structure 20. Further, such a rotation prevention member can be applied to a conventional reinforcing bar and joint where an axial gap is generated between the reinforcing bar and the joint when the reinforcing bar and the joint are screwed together.

[0075] Further, the rotation prevention member 40 may be configured to more strongly prevent relative rotation of the rotation prevention member 40 with respect to the joint structure 20 by fitting the irregularly shaped outer portion thereof into a receiving portion that can receive the irregular shape provided at the axial end portion of the joint structure 20.

[0076] Further, the joint structure 20 has a concave portion 26 with an open end 28 such that the rib 4 is displaced in the circumferential direction and enters the concave portion 26. However, the shape of the joint structure may be set such that the rib 4 fits into the concave portion 26 from the radial direction.

[0077] Specifically, FIG. 12 shows another example of the joint structure 50, where (a) is a plan view, (b) is a front view, and (c) is a cross-sectional view taken along line A-A of (b). The concave portion 56 of the joint structure 50 has a shape symmetric with respect to a symmetry axis parallel to the axial direction, such as a substantially elliptical shape, a substantially oval shape, a substantially lip shape, a substantially rugby ball shape, a substantially oval shape, a substantially rhombic shape, etc. in a radial view. That is, it forms a closed end with both circumferential ends closed, and has a shape similar or approximate to the shape of the rib 4 in a radial view. Of course, in the joint structure 50, the rib 4 abuts against a portion of the inner peripheral surface other than the large-diameter surface 22 and the concave portion 56.

[0078] Further, the joint structure 50 has a slit 52, a thin portion 54, and a confirmation hole 58. The slit 52 extends in the axial direction at a location (where the large-diameter surface 22 is arranged) that is shifted in phase by about 90° with respect to the concave portion 56. The thin portion 54 is opposed to the slit 52 across the axis and is formed to be elastically deformable so as to expand the internal space by thinning a part of the thickness of the large-diameter surface 22. The slit 52 and the thin portion 54 function as an expansion portion for expanding the internal space defined by the inner peripheral surface of the joint structure 50.

[0079] The confirmation hole 58 penetrates the inside and outside of the joint structure 50 so that the inside can be visually recognized. Further, the confirmation hole 58 opens with a size necessary for visual recognition within at least a predetermined range along the axial direction centered on a substantially central portion in the axial direction of the joint structure 50.

[0080] In the initial state where the thin-walled portion 54 is not elastically deformed, when the joint structure 50 is rotated relative to the rod-shaped body 1 with the rod-shaped body 1 inserted and the rib 4 is displaced circumferentially from the position facing the large-diameter surface 22, the inner peripheral surface can interfere with the rib 4 to restrict relative rotation. At this time, if the thin-walled portion 54 is bent and elastically deformed so that the width of the slit 52 is expanded along the arrow shown in FIG. 13, the insertion hole of the joint structure 50 can be expanded in diameter, and the interference in the axial direction between the rib 4 of the rod-shaped body 1 and the engaging convex portion of the joint structure 50 is alleviated. Therefore, the inner peripheral surface and the rib 4 are in a non-interfering state, and the joint structure 50 can rotate relative to the rod-shaped body 1, so that the rib 4 fits into the concave portion 56.

[0081] Note that the slit 52 only needs to be one that cuts out at least a part of the circumferential direction of the joint structure 50 and can be set as appropriate. For example, as shown in FIG. 14, a slit 52 in the shape of a dovetail groove may be provided. In the case of the dovetail groove-shaped slit 52, the range in which the slit 52 can expand can be restricted. That is, as shown in FIG. 15(a), by loosely fitting the convex portion 102 into the dovetail groove-shaped concave portion 100, the convex portion 102 that fits into the concave portion 100 is positioned so as to be displaceable in the circumferential direction as shown in FIG. 15(b), and the range in which the slit 52 expands can be restricted. The restriction of the expansion range of this slit 52 is such that the mutual contact in the process of receiving the rib 4 of the rod-shaped body 1 with respect to the inner periphery of the joint structure 50 is released, and the interference in the axial direction between the rib 4 and the engaging convex portion of the joint structure 50 remains and is not completely released. By doing so, it becomes possible to prevent the rod-shaped body 1 and the joint structure 50 from being pulled out from each other while being relatively rotatable.

[0082] Also, although the slit 52 is expanded by the bending of the thick-thin portion 54 and the cross-sectional area of the insertion hole of the joint structure is increased to expand the internal space, the configuration for expanding the internal space can be set as appropriate, and a plurality of separable parts in the radial direction may be made to function as expansion parts. However, a separate member or mechanism that supports the parts substantially integrally and can displace them in the radial direction and / or the circumferential direction is required.

[0083] Here, FIG. 16 shows a partial body 60 forming a part of the joint structure, where (a) is a perspective view and (b) is a view showing the outer peripheral surface on the connecting portion side. The partial body 60 has a substantially semi-cylindrical shape obtained by radially bisecting the joint structure, and the joint structure is constituted by a pair of partial bodies 60.

[0084] The partial body 60 has a connecting portion 62 in which a plurality of concave portions 62a and convex portions 62b having a dovetail groove shape are provided in the circumferential direction end face in the axial direction. Further, the partial body 60 has a concave portion 56 on the inner peripheral surface side. That is, the inner peripheral surface of the partial body 60 on the connecting portion 62 side becomes a surface forming a part of the large-diameter surface 22.

[0085] FIG. 17 is a perspective view showing a joint structure constituted by partial bodies. The partial bodies 60a and 60b can constitute the joint structure 50 by connecting their respective connecting portions 62, that is, fitting one convex portion into the other concave portion and one concave portion into the other convex portion. The joint structure 50 configured in this way can set the radial displacement amount by loosely fitting the convex portion into the dovetail groove-shaped concave portion as described above. As a result, the partial bodies 60a and 60b can be displaced in the radial direction while being connected to each other to form the joint structure 50, making the size of the internal space, or the diameter of the internal space, etc. variable and expandable.

[0086] Note that the joint structure is not limited to being constituted by two partial bodies, and may be constituted by three or more partial bodies. Further, the partial bodies may be connected by a separate elastic member in addition to providing a connecting portion. For example, a plurality of partial bodies may be arranged in a joint shape and surrounded by an elastic member such as a C-ring or a coil spring. Alternatively, as an expansion portion for expanding the internal space of the joint structure, elastic portions that are elastically deformable in the circumferential direction and along the axial direction may be provided at two or more appropriate positions in the circumferential direction to be configured to be able to expand the diameter. Even in this way, the partial bodies can be separated from each other in the radial direction.

[0087] As described above, by making the concave portion symmetric, the joint structure and the rod-shaped body can be connected, and the joint structure can be easily positioned and fixed at a desired axial position of the rod-shaped body, the connectivity between the rod-shaped bodies is improved, and in a hardening fluid such as concrete which is a hydraulic solidified body or other than the concrete, for example, a hardening fluid such as mortar or resin, the joint structure and the rod-shaped body are embedded before hardening, and thereafter, the pull-out strength in the embedded state after hardening can be improved. Further, if the concave portion is symmetric, after fitting the rib into the concave portion, the relative rotation of the joint structure with respect to the rod-shaped body is restricted, and the rib is prevented from coming off from the concave portion. As a result, the connection between the joint structure and the rod-shaped body can be made stronger.

[0088] Note that the outer shape of the joint structure is not particularly limited, but it is preferably a shape having at least a two-sided width in order to easily apply torque for relative rotation with respect to the rod-shaped body. Further, the joint structure may have a polygonal outer shape including a star shape, etc., such as the hexagonal cylindrical joint structure 20 shown in FIG. 18. Of course, the joint structure may be cylindrical, a shape having a two-sided width in a part of the axial direction, or a shape having only a part of the axial direction being polygonal.

[0089] Further, the confirmation hole 58 may have a central position suggesting means for suggesting the central portion in the longitudinal direction of the joint structure. Specifically, as shown in FIG. 18, a constricted portion 58a with a narrow opening is provided at a position corresponding to a substantially central portion in the axial direction of the joint structure. Thereby, when the rod-shaped bodies are inserted into both ends of the joint structure respectively, the positions of the respective rod-shaped bodies can be visually recognized, and the positions of the respective rod-shaped bodies with respect to the central portion in the axial direction of the joint structure can be grasped simultaneously and easily.

[0090] Here, the connection of the two rod-shaped bodies 1a and 1b by the joint structure 20 will be described with reference to FIG. 19. First, the rod-shaped body 1a is inserted into one end side in the axial direction of the joint structure 20 shown in FIG. 19(a), and the joint structure 20 is displaced to the rod-shaped body 1a side. At this time, on the inner peripheral surface of the joint structure 20, the large-diameter surface 22 faces the rib 4 of the rod-shaped body 1a.

[0091] Also, the axial position of the joint structure 20 with respect to the rod-shaped body 1a is set such that the other end face of the joint structure 20 in the axial direction is substantially flush with the end face of the rod-shaped body 1a in the axial direction or the end face is slightly exposed to the outside. The joint structure 20 is temporarily fixed by being relatively rotated with respect to the rod-shaped body 1a so as to rotate a small angle clockwise as indicated by the arrow in FIG. 19(b), that is, so that the rib 4 is slightly fitted into the concave portion 26.

[0092] Alignment of the axial centers of the joint structure 20 and the rod-shaped body 1b, alignment of the ribs of the rod-shaped bodies 1a and 1b temporarily fixed to the joint structure 20, etc. are performed. Also, the other end of the joint structure 20 is made adjacent to the end face of the rod-shaped body 1b, and the temporary fixing state of the joint structure 20 with respect to the rod-shaped body 1a is released. That is, the joint structure 20 is rotated counterclockwise with respect to the rod-shaped body 1a to a state where it can be relatively displaced in the axial direction.

[0093] Next, the joint structure 20 is relatively displaced in the axial direction with respect to the rod-shaped body 1a so that the rod-shaped body 1b is inserted through the other end portion side in the axial direction. That is, the joint structure 20 is displaced toward the rod-shaped body 1b side so that the rod-shaped body 1b is inserted into the other end portion side of the joint structure 20. As a result, as shown in FIG. 19(c), the rod-shaped body 1b can be relatively displaced in the opposite direction to when the rod-shaped body 1a was inserted and inserted into the joint structure 20.

[0094] At this time, as shown in FIG. 19(c), a confirmation hole 58 is provided on the outer periphery of the joint structure 20, so the positions of the ends of the rod-shaped bodies 1a and 1b can be grasped through the confirmation hole 58. Also, the position of the central portion in the axial direction can be grasped by the constricted portion 58a of the confirmation hole 58, and the axial positions of the respective rod-shaped bodies 1a and 1b within the joint structure 20 can be grasped substantially accurately.

[0095] Then, as shown in FIG. 19(d), by rotating the joint structure 20 clockwise with respect to the rod-shaped bodies 1a and 1b, the rod-shaped bodies 1a and 1b can be connected via the joint structure 20.

[0096] Although the concave portion of the joint structure has been described as having an asymmetric shape or a symmetric shape, of course, an asymmetric concave portion and a symmetric concave portion may be arranged in the axial direction. In that case, the concave portions may be arranged such that the asymmetric ones and the symmetric ones are alternately arranged, or a hybrid structure may be adopted in which several symmetric concave portions are arranged among a plurality of asymmetric ones at appropriate intervals, or other appropriate combined arrangements may be used.

[0097] Of course, the concave portion is not limited to non-spiral shapes such as asymmetric and symmetric shapes, and may be a spiral shape. Also, the spiral shape may be continuously extending, or may be such that substantially spiral concave portions are arranged intermittently along a virtual spiral path. And ribs may be fitted into the spiral concave portion so as to be relatively displaced along the direction of the spiral. In this case, the spiral shape is set to a so-called right-handed spiral groove that guides the displacement direction of the rib 4 by allowing the inner peripheral surface of the concave portion to be in sliding contact with the surfaces 14a and 14d of the rib 4. Of course, it goes without saying that the inner peripheral surface of the concave portion may be in sliding contact with the surfaces 14b and 14c to set a so-called left-handed spiral groove that guides the displacement direction of the rib 4. As a result, the joint structure can be displaced in the axial direction by relative rotation with respect to the rod-shaped body. In addition, when the concave portion is spiral, the shape of the radial end portion of the engaging convex portion can be appropriately set, for example, it can be set from a planar shape, a convex curved surface shape, an acute angle shape, a pointed shape, etc. Also, the concave portion forming the spiral shape can have its groove width shape appropriately set, such as being gradually or stepwise narrowed from one axial end to the middle portion, etc., so that the groove shape forming the spiral can be appropriately set.

[0098] In addition, the joint structure may have both a non-spiral concave portion and a spiral concave portion. FIG. 20 shows a joint structure 70 having a non-spiral concave portion and a spiral concave portion. (a) is a perspective view, (b) is a front view, and (c) is a cross-sectional view taken along the line A-A of (b). The joint structure 70 has a non-spiral concave portion 72a arranged on one end side and a spiral concave portion 72b arranged on the other end side with a midpoint in the axial direction as a boundary. Needless to say, in such a hybrid structure of the concave portion, it goes without saying that the boundary between the non-spiral region and the spiral region may have a structure in which they are directly connected or a structure with an appropriate interval.

[0099] Further, the joint structure 70 has engagement holes 74 at both ends. The engagement holes 74 are located at the ends of the insertion holes of the joint structure 70 and have a tapered shape in which the inner peripheral surface expands toward the opening. Further, on the inner peripheral surface of the engagement hole 74, flat knurls along the axial direction are formed. Note that the engagement holes 74 are set to a hole shape with a larger diameter than the insertion holes of the joint structure 70 so that a relative rotation preventing member 80 described later can be interposed between the engagement holes 74 and the rod-like body 1.

[0100] Here, the engagement hole 74 has a tapered shape, but it is not necessarily required to be a tapered shape. It may be straight, curved, or curved. However, when absorbing dimensional errors and the like, it is preferably a tapered shape.

[0101] FIG. 21 shows a relative rotation preventing member 80 that engages with the joint structure 70. (a) is a perspective view, (b) is a side view, and (c) is a cross-sectional view. The relative rotation preventing member 80 has a substantially ring-shaped main body portion 82 and a flange portion 84. Here, a configuration with a flange portion 84 is provided, but this is not necessarily required. Further, the relative rotation preventing member 80 has an inner peripheral surface 86 that surrounds the rod-like body 1.

[0102] The main body portion 82 has an outer shape that can engage with the engagement hole 74. That is, the outer peripheral surface of the main body portion 82 has a tapered shape that gradually reduces in diameter from the flange portion 84 side corresponding to the inner peripheral surface of the engagement hole 74. Further, on the outer peripheral surface of the main body portion 82, flat knurls along the axial direction are formed. Note that the outer peripheral shape of the main body portion 82 is not limited to a tapered shape and can be set to a straight shape, a curved shape, a curved shape, etc., and is preferably a shape corresponding to the engagement hole 74. In addition, the flat knurls along the axial direction are not necessarily limited to a flat shape, and can be appropriately set as long as they can engage with the means for preventing rotation provided in the engagement hole 74 to prevent relative rotation.

[0103] The flange portion 84 is set to have an outer diameter larger than that of the main body portion 82, and a plurality of irregularities 84a are formed along the circumferential direction on the end surface in the axial direction. These irregularities 84a preferably form a sawtooth shape, and it is preferable that the direction in which the irregularities 84a extend, that is, the direction in which the ridge lines extend, is set along the radial direction of the relative rotation prevention member 80. As a result, the irregularities 84a on the end surface of the flange portion 84 extend radially from the axis.

[0104] The inner peripheral surface 86 is composed of a pair of interference surfaces 86a that can interfere with the rib 4 without contacting the reduced diameter surface 2 of the rod-shaped body 1, and a pair of non-contact surfaces 86b that face the rib 4 with a space therebetween. That is, the interference surfaces 86a and the non-contact surfaces 86b of the inner peripheral surface 86 are alternately arranged along the circumferential direction. That is, the hole defined in the inner peripheral surface 86 can function as a non-circular rod-shaped body insertion hole whose shape in the axial view substantially corresponds to the outer shape of the rod-shaped body 1 in the axial direction.

[0105] When the relative rotation prevention member 80 is interposed between the joint structure 70 and the rod-shaped body 1, it can restrict the relative rotation of the joint structure 70 with respect to the rod-shaped body 1. Specifically, the relative rotation prevention member 80 is arranged in a state of surrounding the outer peripheral surface of the rod-shaped body 1 in advance. At this time, the rod-shaped body 1 fits into the rod-shaped body insertion hole in a state where relative rotation is impossible.

[0106] Next, the rod-shaped body 1 is inserted through both ends of the joint structure 70, and the rib 4 is fitted into the concave portions 72a and 72b. The relative rotation prevention member 80 is inserted into the engagement hole 74 by sliding along the axial direction toward the joint structure 70 side. Then, the flat knurls of the main body portion 82 and the flat knurls of the engagement hole 74 of the joint structure 70 are engaged in the circumferential direction. That is, the irregularities of the flat knurls of each other are aligned and engaged in the circumferential direction.

[0107] As a result, the relative rotation prevention member 80 engages circumferentially with each of the rod-shaped body 1 and the joint structure 70. That is, the flat knurls on the outer periphery of the main body portion 82 engage circumferentially with the flat knurls of the engagement hole 74. On the other hand, when the interference surface 86a of the inner peripheral surface 86 is displaced circumferentially from the position facing the reduced-diameter surface 2 of the rod-shaped body 1, it interferes with the rib 4. As a result, the inner peripheral surface 86 engages circumferentially with the rod-shaped body 1.

[0108] Next, FIG. 22 shows the relative displacement prevention member 90, where (a) is a perspective view, (b) is a side view, and (c) is a cross-sectional view. The relative displacement prevention member 90 is a hollow member having a substantially hexagonal outer shape and a hole 90a through which the rod-shaped body 1 can be surrounded, and has a spiral groove portion 92 continuous with the inner peripheral surface. Further, the relative displacement prevention member 90 has a flange-shaped one end portion, and a plurality of uneven portions 94 are formed along the circumferential direction on one end surface in the axial direction. The uneven portion 94 is configured to have an appropriate shape that can engage with the unevenness 84a of the flange portion 84 and undulates, but here it is set to have a saw blade shape and extend radially from the axis.

[0109] Therefore, at the location where the relative rotation prevention member 80 and the relative displacement prevention member 90 are in contact, the unevenness 84a and the uneven portion 94 function as a relative rotation prevention mechanism that prevents the relative rotation of the two members 80 and 90.

[0110] The spiral direction of the spiral groove portion 92 and the like are set so that the rib 4 of the rod-shaped body 1 can be fitted. Of course, the spiral direction can be set as appropriate, but here the spiral direction of the spiral groove portion 92 is set to a left-handed spiral opposite to the spiral of the concave portion 72b. By fitting the rib 4 into the spiral groove portion 92, it engages with the rib 4 to restrict the axial displacement, but when the relative displacement prevention member 90 itself is rotated, it can be displaced axially with respect to the rod-shaped body 1.

[0111] The connection between the joint structure 70 and the rod-shaped body 1 with the rigid connection structure combining the above-described relative rotation prevention member 80 and relative displacement prevention member 90 will be described. Note that two rod-shaped bodies 1a and 1b are inserted into the joint structure 70, the rib 4 of one rod-shaped body 1a is fitted into the concave portion 72a, and the rib 4 of the other rod-shaped body 1b is fitted into the right-handed spiral concave portion 72b.

[0112] In this case, first, start with the connection of the other rod-shaped body 1b. Specifically, position the rod-shaped body 1b at the opening at the other end (the upper end in FIG. 23) of the joint structure 70 and align it so that the concave portion 72b can be fitted to the rib 4. Next, as shown in FIG. 23(a), when the joint structure 70 is relatively rotated in the right direction with respect to the rod-shaped body 1b, the rod-shaped body 1b is relatively displaced toward the inside of the joint structure 70. That is, due to the rotation of the joint structure 70, the rib 4 fitted in the concave portion 72b is guided in the direction of the helix, and as a result, the rod-shaped body 1b is relatively displaced along the helix and moves to the innermost part along the concave portion 72b.

[0113] Next, connect one rod-shaped body 1a. Specifically, as shown in FIG. 23(b), insert the rod-shaped body 1a into the insertion hole from one end side in the axial direction of the joint structure 70, and insert it while confirming the depth position of the rod-shaped body 1a by the confirmation hole 58. At this time, align the reduced-diameter surface 2 of the rod-shaped body 1a with the position facing the concave portion 72a of the joint structure 70. Then, as shown in FIG. 23(c), by relatively rotating the joint structure 70 counterclockwise by a predetermined angle, here about 90°, with respect to the rod-shaped body 1a, the rib 4 enters and fits into the concave portion 72a, and the joint structure 70 and the rod-shaped body 1a are engaged in the axial direction.

[0114] Next, install the relative rotation prevention member 80. Specifically, as shown in FIG. 24(a), slide the relative rotation prevention member 80 previously inserted into the rod-shaped body 1a (1b) toward the joint structure 70 side while surrounding the rod-shaped body 1a (1b) and insert it into the engagement hole 74. Also, prior to the relative rotation prevention member 80, a relative displacement prevention member 90 previously screwed in the left direction into the rod-shaped body 1a (1b) is relatively rotated in the direction of advancing toward the relative rotation prevention member 80 side, that is, in the left direction with respect to the rod-shaped body 1a (1b). As a result, the unevenness 84a on the end face of the flange portion 84 and the uneven portion 94 come close to and contact each other, and the unevennesses of each other are engaged.

[0115] By combining the relative rotation prevention member 80 and the relative displacement prevention member 90 in this way, the rod-shaped body 1 and the joint structure 70 can be connected more firmly. That is, since the inner circumference of the relative rotation prevention member 80 engages with the rod-shaped body 1 in the circumferential direction and the outer circumference engages with the joint structure 70 in the circumferential direction, when one of the joint structure 70 and the rod-shaped body 1 rotates relative to the other, the relative rotation prevention member 80 restricts the rotation. Therefore, the state in which the rib 4 is fitted into the concave portions 72a and 72b can be firmly maintained. Further, since the relative displacement prevention member 90 is arranged axially outside the relative rotation prevention member 80, it is possible to surely prevent the relative rotation prevention member 80 from axially coming off from the engagement hole 74.

[0116] Further, the relative displacement prevention member 90 can be easily displaced in the circumferential direction with respect to the rod-shaped body 1, but the flange portion 84 and the concavo-convex portion 94 engage with each other in the circumferential direction, preventing the relative displacement prevention member 90 from rotating in a direction in which it can be separated from the joint structure 70, and firmly fixing the relative rotation prevention member 80 and the relative displacement prevention member 90. Therefore, it becomes possible to connect the rod-shaped body 1, the joint structure 70, the relative rotation prevention member 80, and the relative displacement prevention member 90 in a substantially integrated manner and very firmly, and it is possible to eliminate the need for injecting fluid curable filling materials such as mortar, grout, and adhesive, which were conventionally essential.

[0117] Note that the above-described confirmation hole may be closed by a member having light transmissivity such as a transparent film or a transparent resin material as long as at least the rod-shaped body inside the joint structure can be visually recognized.

[0118] Note that the relative rotation prevention member 80 has a cylindrical main body portion, but it may have a shape that can be elastically deformed in the radial direction. For example, as shown in FIG. 25, a slit portion 87 extending along the axial direction may be formed in the main body portion 82. The slit portions 87 may be formed at predetermined intervals along the circumferential direction, or may be formed by cutting out a part of the non-contact surface 86b along the axial direction as shown in FIG. 25(b). Further, as shown in FIG. 25(c), the slit portion 87 may be formed by widely forming the main body portion 82 in the circumferential direction, and the size and number can be appropriately set. By forming such a slit portion 87, the main body portion 82 can be elastically deformed and / or plastically deformed so as to bend inward, and can be more firmly adhered to the rod-shaped body 1. That is, since the outer peripheral surface of the main body portion 82 is intermittently divided in the circumferential direction by the slit portion 87, each is liable to be elastically deformed and / or plastically deformed. Further, when the main body portion 82 is elastically deformed and / or plastically deformed inward in the radial direction, the inner peripheral surface of the main body portion 82 closely contacts the outer peripheral surface of the rod-shaped body 1 and presses inward in the radial direction. As a result, the relative rotation prevention member 80 can be more firmly fixed to the rod-shaped body 1. Further, the outer peripheral surface of the main body portion 82 has a tapered shape corresponding to the inner peripheral surface of the engagement hole 74, but by making it a tapered shape different from the tapered shape of the engagement hole 74 or the like, the shape may be set so as to be pressed inward in the radial direction from the inner peripheral surface of the engagement hole 74. Specifically, if the taper angle is slightly gentler than the taper angle of the engagement hole 74 and the outer diameter of the axial tip of the main body portion 82 exceeds the inner diameter of the innermost part of the engagement hole 74, the main body portion 82 is gradually pressed from the inner peripheral surface of the engagement hole 74 as it enters the engagement hole 74. Therefore, it can be surely elastically deformed inward in the radial direction and firmly adhered to the rod-shaped body 1.

[0119] Further, the joint structure may have a configuration capable of inserting rod-shaped bodies having different diameters at one end portion and both end portions in the axial direction. That is, the joint structure may be for connecting rod-shaped bodies having different diameters. In that case, the cross-sectional area and diameter of the first range from one end portion side in the axial direction to the middle portion and the cross-sectional area and diameter of the second range from the other end portion side in the axial direction to the middle portion may be configured to be different.

[0120] Further, the joint structure is not limited to being constituted by a single member, and may be constituted by a plurality of members. For example, as shown in FIG. 26, the joint structure 130 may be constituted by two cylindrical members 110 and 120 divided in the axial direction. The cylindrical member 110 has an opening at one end in the axial direction through which the rod-shaped body 1 can be inserted, and a connecting portion 112 formed by a spiral groove is arranged on the outer peripheral surface of the other end. Further, as shown in FIG. 26(b), on the inner peripheral surface of the cylindrical member 110, a large-diameter surface 22 arranged at positions opposite to each other across the axial center, an engaging convex portion 24 and a concave portion 26 adjacent to the large-diameter surface 22 in the circumferential direction are arranged.

[0121] The cylindrical member 120 has an opening at one end in the axial direction through which the rod-shaped body 1 can be inserted, and has a surrounding portion 122 at the other end. The surrounding portion 122 has a large-diameter shape so as to be able to surround the connecting portion 112 by the inner peripheral surface, and a spiral convex portion extending in a spiral shape and fitting into the spiral groove of the connecting portion 112 is provided on the inner peripheral surface. Further, on the inner peripheral surface of the cylindrical member 110, a large-diameter surface 22 arranged at positions opposite to each other across the axial center, an engaging convex portion 24 and a concave portion 26 adjacent to the large-diameter surface 22 in the circumferential direction are arranged.

[0122] The cylindrical members 110 and 120 constitute a joint structure 130 by being screwed and connected with the surrounding portion 122 around the connecting portion 112 (see FIG. 27). Of course, the structure for connecting the cylindrical members 110 and 120 is not limited to this, and it is sufficient that these cylindrical members 110 and 120 are connected so as to be relatively rotatable and restrict relative displacement in the axial direction. For example, it goes without saying that a configuration using a third member or the like for connection may also be adopted.

[0123] By configuring such a joint structure 130, when inserting the rod-shaped bodies 1 and 1 through both ends in the axial direction, it is possible to absorb the defect in connection due to the phase shift between the rod-shaped bodies 1 and 1. That is, when the positions of the ribs 4 are different between the rod-shaped bodies 1 and 1, even if the concave portion 26 is fitted to the rib 4 of one rod-shaped body 1, there is a possibility that the rib 4 of the other rod-shaped body 1 may not be fitted to the concave portion 26, but this can be absorbed and prevented. Specifically, if at least one of the cylindrical members 110 and 120 is rotated by at least a small angle (less than 90°), it is possible to surely fit the ribs 4 of the rod-shaped body 1 to be inserted into the concave portion 26 for both the cylindrical members 11 and 120.

Explanation of Reference Numerals

[0124] 1…Rod-shaped body 2…Reduced-diameter surface 4…Rib 4a…End face 6…Concave-diameter surface 10…Tip portion 12…Ridge line 14a~14d…Surfaces 20…Joint structure 22…Large-diameter surface 24…Engaging convex portion 26…Concave portion 28, 32…Open ends 29…Stopper 40…Rotation prevention member 42…Spacer portion 44…Hole 52…Slit 58…Confirmation hole 60…Sub-body 74…Engaging hole 80…Relative rotation prevention member 82…Main body portion 84…Flange portion 90…Relative displacement prevention member 92…Spiral groove portion 94…Convex and concave portion.

Claims

1. A joint structure having an insertion hole through which a rod-shaped body can be inserted along the axial direction, and engaging the inner circumference with a rib of the rod-shaped body to connect the rod-shaped body, on the inner circumference, there are engagement convex portions arranged in the axial direction and capable of engaging with the rib, at least one or more concave portions having a non-spiral shape that alternate with the engagement convex portions in the axial direction and are recessed so as to be able to fit the rib, having a large-diameter surface that is adjacent to the engagement convex portion and the concave portion in the circumferential direction and is not engaged with the rib, the concave portion has a hybrid structure in which the non-spiral shape forms a symmetric shape and an asymmetric shape with the axial direction as the axis of symmetry in a radial view, and is arranged in the axial direction, and the symmetric shape and the asymmetric shape are arranged, A joint structure characterized by fitting the rib into the concave portion to restrict the axial displacement of the rod-shaped body.

2. A joint structure having an insertion hole through which a rod-shaped body can be inserted along the axial direction, and engaging the inner circumference with a rib of the rod-shaped body to connect the rod-shaped body, on the inner circumference, there are engagement convex portions arranged in the axial direction and capable of engaging with the rib, at least one or more concave portions that alternate with the engagement convex portions in the axial direction and are recessed so as to be able to fit the rib, having a large-diameter surface that is adjacent to the engagement convex portion and the concave portion in the circumferential direction and is not engaged with the rib, the insertion hole has a substantially oval or substantially elliptical hole shape in an axial view, A joint structure characterized by fitting the rib into the concave portion to restrict the axial displacement of the rod-shaped body.

3. The symmetric shape has closed ends at both circumferential ends, The main body of the joint structure has an expansion portion that can expand the internal space, The expansion portion is characterized in that it can transition between a state in which the rib is received by the inner circumference and a process state in which the insertion hole is expanded to receive the rib by the inner circumference. The joint structure according to claim 1.

4. The joint structure according to claim 3, wherein the extension portion has an elastic deformation mechanism and / or a radial separation mechanism.

5. The joint structure according to claim 1, wherein one end in the circumferential direction of the asymmetric concave portion is an open end, and the rib can be received from the open end side.

6. The joint structure according to claim 5, wherein the other end in the circumferential direction of the asymmetric concave portion is a closed end, and the circumferential displacement of the rib can be restricted by the closed end.

7. The concave portion forms a spiral shape. The joint structure according to claim 2, wherein the radial end portion of the engaging convex portion forms a planar shape, a convex curved surface shape, or an acute angle shape.

8. The joint structure according to claim 7, wherein the concave portion forming a spiral shape is formed continuously or intermittently along a virtual spiral path.

9. The joint structure according to claim 7, wherein the concave portion forming a spiral shape is formed continuously, and the width of the concave portion is configured to gradually or stepwise decrease from one end in the axial direction to the middle portion.

10. The joint structure according to any one of claims 1 to 9, wherein the insertion hole has a hole shape that is substantially similar or approximate to the outer shape of the rod-shaped body in the axial direction view.

11. The joint structure according to claim 10, wherein the insertion hole has a two-sided width portion, and the inner circumferential surface is formed by an arc that is convex with a predetermined radius of curvature connecting between opposite ends of the opposing two-sided width portions.

12. The joint structure according to any one of claims 1 to 11, wherein the insertion hole has different cross-sectional areas in a first range in the middle portion from one end in the axial direction and a second range in the middle portion from the other end in the axial direction.

13. The joint structure according to claim 2, wherein the concave portion from one axial end to the middle portion is spiral, and the concave portion from the other end to the middle portion is non-spiral.

14. The joint structure according to any one of claims 1 to 13, characterized in that a relative rotation prevention member for preventing relative rotation with a rod-shaped body is provided at at least one axial end.

15. The joint structure according to any one of claims 1 to 13, characterized in that a relative displacement prevention member for preventing relative displacement in the axial direction with a rod-shaped body is provided at at least one axial end.

16. A rigid connection structure is provided at the axial end, The rigid connection structure has a relative rotation prevention member for preventing relative rotation with a rod-shaped body and a relative displacement prevention member for preventing relative displacement with respect to the rod-shaped body, and is the joint structure according to any one of claims 1 to 13.

17. The joint structure according to claim 14 or 16, wherein the relative rotation prevention member surrounds the rod-shaped body and is inserted into the engagement hole.

18. The relative rotation prevention member has an engagement surface that engages with the inner circumference of the engagement hole, and a non-circular rod-shaped body insertion hole that substantially corresponds to the outer shape of the rod-shaped body in the axial view, and The rod-shaped body can be fitted into the rod-shaped body insertion hole in a state where relative rotation is impossible, and the engagement surface engages with the inner circumference of the engagement hole, and is the joint structure according to claim 14, claim 16, or claim 17.

19. The joint structure according to claim 15 or 16, wherein the relative displacement prevention member engages with a rib of the rod-shaped body, and axial displacement is restricted.

20. The joint structure according to claim 15, 16, or 19, wherein the relative displacement prevention member has a hole portion through which the rod-shaped body can be inserted and has a spiral groove on the inner circumferential surface.

21. The joint structure according to claim 16, wherein a relative rotation prevention mechanism for preventing relative rotation between the relative rotation prevention member and the relative displacement prevention member is provided at the contact portion between the relative rotation prevention member and the relative displacement prevention member.

22. The joint structure according to any one of claims 1 to 21, characterized in that at an appropriate intermediate position in the longitudinal direction of the main body, there is a confirmation hole penetrating inside and outside to make the insertion depth of the rod-shaped body visible.

23. The joint structure according to claim 22, characterized in that the confirmation hole has a central position suggesting means indicating the central portion in the longitudinal direction.

24. The joint structure according to claim 23, characterized in that the confirmation hole has a constricted portion with a constricted shape at a location corresponding to the central portion in the longitudinal direction, and the constricted portion forms the central position suggesting means.

25. The joint structure according to any one of claims 22 to 24, characterized in that the confirmation hole is closed by a member having light transmissibility.

Images