Joint Structure

Abstract

To provide a joint structure which can connect any reinforcement core material without disturbing a pitch of a screw blade, can galvanize a connection part, can be manufactured at low cost, and is mainly used in a reinforcement core material with a screw blade.SOLUTION: A joint structure 1 for connecting a first tubular member 2 and a second tubular member 3, wherein the first tubular member 2 has a hole part 22 on its peripheral wall and a groove part 23 which is formed into a taper surface gradually deeper toward the hole part 22, and the second tubular member 3 has a through hole 33, a pin member 34 provided in the through hole 33 in a forward movable and retractable manner, and a linear spring 35 for energizing the pin member 34 toward the outside.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a joint structure used mainly in a reinforcing core material with screw flights. [Background technology]

[0002] A widely used method of natural ground reinforcement is to increase the stability of slopes by inserting rod-shaped reinforcing core materials such as reinforcing bars or steel rods into the ground.

[0003] One example of such a ground reinforcement method is a method in which a cylindrical reinforcing core material with a discharge outlet on the side is cast into the ground, grout is pressed into the reinforcing core material, and the grout is then discharged from the discharge outlet around the reinforcing core material, filling it with the surrounding soil and allowing it to harden, thereby fixing the reinforcing core material to the ground (see Patent Document 1).

[0004] However, since methods that use grout pollute the environment, methods have been developed that fix the reinforcing core material to the ground without using grout.One such new method is a method that uses a reinforcing core material with screw blades, which is a rod-shaped reinforcing core material with screw blades attached (see Patent Document 2).

[0005] In this method, the reinforcing core material with screw blades is installed in the ground by being screwed and inserted into the ground while rotating, and the screw blades penetrate into the surrounding soil, allowing the reinforcing core material to be fixed to the ground without the use of grout.

[0006] The screw-flighted reinforcing core material is installed in the natural ground using a boring machine. The number of screw-flighted reinforcing core materials to be connected is adjusted depending on the condition of the natural ground, and the reinforcing core material located at the most proximal end (i.e., the reinforcing core material closest to the ground when installed in the natural ground) is connected to the spindle of the boring machine. Threaded joints are generally used to connect such screw-flighted reinforcing core materials to each other and to connect the screw-flighted reinforcing core material to the spindle. As the spindle rotates and moves forward, the screw-flighted reinforcing core material also rotates and is screwed into the natural ground to be installed. The proximal end of the screw-flighted reinforcing core material is left protruding from the natural ground by a predetermined length, and a head cap is placed over this protruding portion to complete the installation of the screw-flighted reinforcing core material.

[0007] Such a reinforcing core with screw blades is manufactured by connecting a required number of reinforcing cores and then welding screw blades in a spiral pattern at a constant pitch around the reinforcing cores. Since the reinforcing core with screw blades is installed in the ground without grout, it is exposed to the soil and is susceptible to deterioration in strength due to rust. Therefore, appropriate rust prevention treatments, such as zinc plating, are performed. However, when square threads are used as threaded joints, zinc plating of the threads and grooves is difficult because it makes the screw impossible to tighten. Therefore, it is possible to change the threaded portion of the threaded joint to a rope thread, which allows for zinc plating, or to apply electroless plating to the square threads, which allows for screw tightening. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-252319 [Patent Document 2] Special Publication No. 2-62648 Summary of the Invention [Problem to be solved by the invention]

[0009] However, when connecting multiple conventional reinforcing core materials with screw blades using threaded joints, the pitch of the screw blades does not match unless the combination is properly welded together, and therefore the reinforcing core material cannot be used if it is damaged, and it is necessary to replace the entire reinforcing core material, which makes it difficult to use.

[0010] Furthermore, as mentioned above, when rope threads are used for threaded joints used to connect reinforcing core materials and to connect reinforcing core materials to spindles, the strength is lower than with square threads, so in addition to zinc plating, strength-improving processes such as quenching are required, which increases the manufacturing cost. Also, when square threads are used and electroless plating is applied, there is the same problem of increased manufacturing costs.

[0011] In view of these conventional problems, the present invention aims to propose a joint structure that can be used primarily for reinforcing core materials with screw blades, which can connect any reinforcing core material without disturbing the pitch of the screw blades, can be zinc-plated at the connection parts, and can be manufactured at low cost. [Means for solving the problem]

[0012] The present invention provides a joint structure for connecting a first tubular member and a second tubular member, wherein the first tubular member has one or more holes formed in a peripheral wall, and a groove formed on an inner peripheral surface continuously with one end side of the hole in the circumferential direction, the groove having a bottom with a tapered surface that gradually becomes deeper toward the hole; the second tubular member has a tubular tip portion that can be inserted into the first tubular member, and has one or more through holes provided at positions facing the hole when the tip portion is inserted into the first tubular member; a pin member that is provided within the through hole and can advance and retreat between a protruding position and a retracted position, and protrudes from the outer peripheral surface of the tip portion at the protruding position; and a biasing means that is provided within the tip portion and biases the pin member radially outward from the tip portion. the hole is an elongated hole whose length in the circumferential direction of the first tubular member is greater than the length of the pin member in the circumferential direction of the first tubular member, and in the protruding position, the pin member protrudes into the hole to position the first tubular member relative to the second tubular member in the insertion direction, and can abut against a wall on the other end side of the hole in the circumferential direction to position the first tubular member in the rotational direction, and when the first tubular member and the second tubular member rotate relatively from the protruding position and the pin member moves toward the one end, the pin member moves from the wall on the one end side of the hole in the circumferential direction onto the groove, moves to the inner circumferential wall of the first tubular member and is positioned at the retracted position, and the positioning by the pin member in the insertion direction is released This is a joint structure characterized by the above.

[0014] In such a joint structure, the biasing means is preferably a linear spring that is substantially C-shaped in plan view.

[0015] In such a joint structure, the biasing means is preferably a snap ring. [Effects of the Invention]

[0016] According to the joint structure of the present invention configured as described above, the first tubular member and the second tubular member are connected by inserting the tip end of the second tubular member into the first tubular member and causing the pin member of the second tubular member to protrude into the hole of the first tubular member. Then, by rotating one of the first tubular member and the second tubular member and abutting the pin member against the peripheral wall on the side not continuous with the groove of the hole, the first tubular member and the second tubular member can be positioned in the rotational direction.

[0017] When the first and second tubular members are reinforcing core materials with screw flights, screw flights are formed continuously at a predetermined pitch in the first and second tubular members in this positioned state. As a result, even if some of the reinforcing core materials constituting the combination when the screw flights are formed are replaced with reinforcing core materials constituting another reinforcing core material with screw flights that is similarly formed, the screw flights will be continuous at the same pitch by positioning them in the same way, so that the reinforcing core materials constituting the reinforcing core material with screw flights can be selected and used as desired.

[0018] Furthermore, by using a pin member to connect the first tubular member and the second tubular member, the problem of not being able to apply zinc plating to the joint portion, which occurs when a square thread is used in a threaded joint, does not occur, and it becomes possible to apply inexpensive zinc plating to the entire joint, including the joint portion, thereby reducing manufacturing costs. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic diagram showing a joint structure according to an embodiment of the present invention; [Figure 2] 2A and 2B are schematic diagrams showing the joint structure of FIG. 1 as viewed from the axial direction, in which (a) shows the state in which the pin member protrudes and is positioned within the hole, (b) shows the state in which the pin member rests on the bottom of the groove, and (c) shows the state in which the pin member has moved beyond the bottom to a retracted position. [Figure 3] FIG. 10 is a schematic diagram showing a pin member and a snap ring as a biasing means used in a joint structure according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of a joint structure according to the present invention will be described with reference to the drawings.

[0021] 1 is a schematic diagram showing a joint structure according to one embodiment of the present invention. The joint structure 1 according to this embodiment connects two tubular members, a first tubular member 2 and a second tubular member 3.

[0022] The first tubular member 2 is a cylindrical steel pipe having an opening 21 at at least one end, and has two circumferentially extending hole portions 22 formed at opposing positions on the peripheral wall, and has a groove portion 23 formed on the inner surface that is continuous with the peripheral wall 222 in the longitudinal direction of the hole portion 22.

[0023] The hole 22 is an elongated hole having a rounded rectangular shape in a plan view, and is formed to penetrate the peripheral wall of the first tubular member 2.

[0024] The groove 23 is a groove formed continuously along the circumferential direction of the peripheral wall 222 of the hole 22. The groove 23 has a tapered surface in which a bottom 231 becomes gradually deeper as it approaches the hole 22.

[0025] The second tubular member 3 has a tubular tip portion 32 that can be inserted into the opening 21 of the first tubular member 2. The tip portion 32 is formed by reducing the outer diameter of the tip portion of the main body portion 31 of the second tubular member 3, and has the same inner diameter as the main body portion 31. The tip portion 32 is formed with two round through holes 33 that are provided at positions facing the hole portion 22 when the tip portion 32 is inserted into the opening 21 of the first tubular member 2. A step portion 312 is formed between the tip portion 32 and the main body portion 31.

[0026] A pin member 34, which is a cylindrical metal member, is provided in each of the two through holes 33 of the tip portion 32 so as to be able to advance and retreat within the through hole 33. The pin member 34 has a through hole 341 formed on one end side.

[0027] A linear spring 35 having a substantially C-shape in a plan view is inserted into the through hole 341 of the pin member 34 and serves as a biasing means for biasing the pin member 34 radially outward from the tip end portion 32.

[0028] Next, we will explain how the first tubular member 2 and the second tubular member 3 are connected and rotated together, and how they are separated, using the joint structure 1 having the above-mentioned configuration. Figure 2 is a schematic diagram showing the joint structure 1 of Figure 1 as viewed from the axial direction, with (a) showing a state in which the pin member 34 is positioned protruding into the hole portion 22, (b) showing a state in which the pin member 34 is resting on the bottom portion 231 of the groove, and (c) showing a state in which the pin member 34 has moved beyond the bottom portion 231 to a retracted position. The position of the pin member 34 protruding into the hole portion 22, as shown in Figure 2(a), is referred to as the "protruding position."

[0029] First, the tip portion 32 of the second tubular member 3 is inserted into the opening 21 of the first tubular member 2. At this time, the operator inserts the tip portion 32 into the opening 21 while manually pushing the pin member 34 into the through-hole 33 of the second tubular member 3 to prevent interference with the pin member 34. Then, the tip portion of the first tubular member 2 abuts against the step portion 312 of the second tubular member 3, thereby positioning the first tubular member 2 and the second tubular member 3 in the insertion direction.

[0030] Next, with the first tubular member 2 and the second tubular member 3 positioned in the insertion direction, one of them is rotated until it reaches a position where the through-hole 33 overlaps with the hole 22. As shown in Fig. 2(a), the tip of the pin member 34 is biased by the linear spring 35 to protrude into the hole 22. This protrusion of the pin member 34 continues until the linear spring 35 abuts against the inner circumferential wall of the tip portion 32, restricting the movement of the pin member 34.

[0031] 2(a), by rotating either the first tubular member 2 or the second tubular member 3 so that the pin member 34 abuts against the peripheral wall 221 on the side not continuous with the groove of the hole 22, the first tubular member 2 and the second tubular member 3 are positioned in the rotational direction. If the rotation continues further in the direction, a rotational force is transmitted from the pin member 34 to the peripheral wall 221, so that the operation of one of the first tubular member 2 and the second tubular member 3 can be made to follow the movement of the other, and the first tubular member 2 and the second tubular member 3 can be rotated integrally.

[0032] Next, we will explain the operation of separating the first tubular member 2 and the second tubular member 3. When either the first tubular member 2 or the second tubular member 3 is rotated in the reverse direction and the pin member 34 is moved in a direction away from the peripheral wall 221, the pin member 34 moves from the peripheral wall 222 located on the opposite side to the peripheral wall 221 onto the bottom portion 231, which is the tapered surface of the groove portion 23, as shown in Figure 2(b), and begins to retreat within the through hole 33 against the biasing force of the linear spring 35, and the pin member 34 is released from the hole portion 22.

[0033] 3(c), the pin member 34 moves up the bottom 231 and further retreats within the through-hole 33 against the biasing force of the linear spring 35, eventually leaving the groove 23 and coming into contact with the inner circumferential wall of the first tubular member 2, and the pin member 34 reaches the retreated position. In this state of FIG. 3(c), the second tubular member 3 can be pulled out of the first tubular member 2, i.e., can be separated.

[0034] Next, another embodiment of the present invention will be described. Fig. 3 is a schematic diagram showing a pin member 4 and a snap ring 5 as a biasing means used in a joint structure according to another embodiment of the present invention.

[0035] In the joint structure according to this embodiment, the structures of the first tubular member 2 and the second tubular member 3 are similar to those of the embodiment described using Figures 1 and 2, but the pin member 4 and snap ring 5 provided inside the second tubular member 3 are different. Below, the pin member 4 and snap ring 5 will be mainly described, and a description of the same configuration as in the embodiment described above will be omitted.

[0036] The pin member 4 is a hat-shaped metal member in a side view, and has a cylindrical main body 41 and a disk-shaped flange 42 formed with an expanded diameter at the end of the main body 41. The main body 41 has a diameter that allows it to be inserted into the through hole 33 of the second tubular member 3 and the hole 22 of the first tubular member 2. On the other hand, the flange 42 has a diameter larger than the diameter of the through hole 33 of the second tubular member 3, and therefore cannot enter the through hole 33, preventing the pin member 4 from coming off the through hole 33.

[0037] The snap ring 5 is made of a metal, which is widely used, and any suitable one can be selected and used.

[0038] The manner in which the first tubular member 2 and the second tubular member 3 are connected and separated using the pin member 4 and the snap ring 5 has been described above with reference to FIG. 2, and therefore a description thereof will be omitted here.

[0039] According to the joint structure 1 of each of the above-described embodiments, the first tubular member 2 and the second tubular member 3 are connected by inserting the tip portion 32 of the second tubular member 3 into the first tubular member 2 and causing the pin member 34(4) of the second tubular member 3 to protrude into the hole portion 22 of the first tubular member 2. Then, by rotating one of the first tubular member 2 and the second tubular member 3 and causing the pin member 34(4) to abut against the peripheral wall 221 on the side not continuous with the groove portion 23 of the hole portion 22, the first tubular member 2 and the second tubular member 3 can be positioned in the rotational direction.

[0040] When the first tubular member 2 and the second tubular member 3 are reinforcing core materials with screw blades, by forming continuous screw blades at a predetermined pitch on the first tubular member 2 and the second tubular member 3 in this positioned state, even if some of the reinforcing core materials that make up the combination when these screw blades are formed are replaced with reinforcing core materials that make up other reinforcing core materials with screw blades that have been similarly formed, the screw blades will be continuous at the same pitch by positioning them in the same way, so the reinforcing core materials that make up the reinforcing core materials with screw blades can be selected and used as desired.

[0041] Furthermore, by connecting the first tubular member 2 and the second tubular member 3 using the pin member 34 (4), the problem of not being able to apply zinc plating to the joint portion, as occurs when a square thread is used in the threaded joint portion, does not occur, and it becomes possible to apply inexpensive zinc plating to the entire portion, including the joint portion, thereby reducing manufacturing costs.

[0042] Furthermore, when the first tubular member 2 and the second tubular member 3 are a combination of a reinforcing core material with screw blades and a boring machine spindle, the reinforcing core material with screw blades can be installed in the ground by rotating the spindle so that the pin member 34(4) abuts against the peripheral wall 221 on the side not connected to the groove portion 23 of the hole portion 22. It goes without saying that the screw blades are formed in an orientation such that the reinforcing core material is screwed into the ground when the spindle is rotated in the direction in which the pin member 34(4) abuts against the peripheral wall 221.

[0043] On the other hand, after installation, by rotating the spindle in the opposite direction to that during installation, the pin member 34(4) can be removed from the hole 22 by climbing up onto the groove 23, which has a tapered surface, from the hole 22, and the reinforcing core material with screw wings and the spindle can be easily separated. Therefore, unlike when using a threaded joint, there is no need to use a tool such as a pipe wrench to separate the reinforcing core material with screw wings from the spindle, and it is only necessary to ensure that the part of the reinforcing core material that protrudes from the ground when installed in the natural ground is only long enough to cover with a head cap.

[0044] Furthermore, in the present invention, the hole 22 formed in the first tubular member 2 can have any shape as long as it can accommodate the pin member 34(4), but by making it an elongated hole extending in the circumferential direction, it is possible to prevent the first tubular member 2 and the second tubular member 3 from separating even if the pin member 34(4) moves slightly toward the groove portion 23. As a result, for example, in the case of connecting the spindle of a boring machine and a reinforcing core material with screw flights, when the boring machine is temporarily stopped, a reaction force may act on the spindle, causing it to rotate slightly in the reverse direction; however, even if such a slight reverse rotation occurs, the connection between the spindle and the reinforcing core material with screw flights can be maintained, and the screwing of the reinforcing core material with screw flights can be immediately resumed.

[0045] Although the embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments, and unless otherwise specifically limited in the above description, various modifications and changes are possible within the spirit and scope of the present invention as set forth in the claims. Furthermore, the effects of the above embodiments are merely examples of the effects that can be obtained from the present invention, and do not mean that the effects of the present invention are limited to the above effects.

[0046] For example, in the joint structure 1 according to each of the above-described embodiments, a linear spring 35 or a snap ring 5 is used as a biasing means for the pin member 34(4), but the present invention is not limited to this, and any member that can bias the pin member 34(4) radially outwardly of the second tubular member 3 while ensuring the forward and backward movement of the pin member 34(4) can be used.

[0047] Furthermore, although the joint structure 1 according to the above-described embodiment has been described as being used to connect reinforcing core materials with screw wings to each other, or to connect a reinforcing core material with screw wings to a spindle of a boring machine, the joint structure according to the present invention is not limited to such uses and can also be suitably used to connect other types of components to each other. [Explanation of symbols]

[0048] 1: Joint structure 2: First tubular member 3: Second tubular member 4, 34: Pin parts 5: Snap ring 21: Opening 22: Hole 23: Groove 32:Tip 33:Through hole 35: Wire spring 41: Main body 42: Flange part 221, 222: Peripheral wall 231: Bottom 312:Dan section 341:Through hole

Claims

1. A joint structure for connecting a first tubular member and a second tubular member, the first tubular member has one or more holes formed in a peripheral wall, and a groove formed in an inner peripheral surface along a peripheral direction continuous with one end side of the hole in a peripheral direction, the groove having a bottom that forms a tapered surface that gradually becomes deeper toward the hole; the second tubular member has a tubular tip portion that can be inserted into the first tubular member, and has one or more through holes provided at a position facing the hole portion when the tip portion is inserted into the first tubular member, a pin member that is provided within the through hole and can advance and retreat between a protruding position and a retracted position, and protrudes from the outer circumferential surface of the tip portion at the protruding position, and a biasing means that is provided within the tip portion and biases the pin member radially outward from the tip portion, the hole is an elongated hole whose length in the circumferential direction of the first tubular member is greater than the length of the pin member in the circumferential direction of the first tubular member, In the protruding position, the pin member protrudes into the hole to position the first tubular member relative to the second tubular member in the insertion direction, and also abuts against a wall on the other end side of the hole in the circumferential direction to position the first tubular member in the rotational direction, When the first tubular member and the second tubular member rotate relative to each other from the protruding position and the pin member moves toward the one end, the pin member moves from the circumferential wall of the hole portion onto the groove portion and moves to the inner wall of the first tubular member to be positioned in the retracted position, thereby releasing the positioning of the pin member in the insertion direction.

2. 2. The joint structure according to claim 1, wherein the biasing means is a linear spring that is substantially C-shaped in a plan view.

3. 2. The joint structure according to claim 1, wherein the biasing means is a snap ring.

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