Centering tool and method of using same

Abstract

A centering tool that can be used to manage the posture of a cylindrical member such as a cylindrical formwork is provided. [Solution] A centering tool 10 according to one embodiment of the present disclosure comprises a first end member 14A and a second end member 14B arranged along a linear first axis 10A, a plurality of expansion / contraction arms 16 that expand and contract around the first axis 10A in a direction perpendicular to the first axis 10A, a plurality of backing plate members 12 that are abutment members provided on the outside of the expansion / contraction arms 16 around the first axis 10A, and tension coil springs 18 that are provided to expand the expansion / contraction arms 16. Each backing plate member 12 is movable around a second axis JA that intersects the first axis 10A. The backing plate members 12 are arranged so that the orientation of the abutment surface 62 facing outward of the backing plate member 12 changes with movement around the second axis JA.

Description

[Technical Field]

[0001] The present disclosure relates to a centering tool that can be used with a tubular member and a method for using the same. [Background technology]

[0002] For example, when a steel pipe is set up vertically as a cylindrical formwork, the level is positioned around the steel pipe and used. Specifically, when the steel pipe is set up vertically and concrete is filled in, the level is frequently moved to multiple locations on the steel pipe.

[0003] For example, in order to secure a place to attach anchor bolts that will be installed after concrete is poured in the substructure of a bridge, i.e., in the abutments or piers, a cylindrical formwork is erected vertically as a box cutout. Specifically, when pouring concrete, a cylindrical formwork such as a steel pipe is installed to prevent concrete from flowing into it, and a "hole" is formed to secure the anchor bolt in a predetermined position. When installing this cylindrical formwork, a spirit level is used, as described above.

[0004] Patent Document 1 discloses a measuring jig for easily and accurately determining the position (relative position) of four or more holes (box-punched portions) formed on the top surface of a bridge pier to secure a bearing device between a bridge girder and a pier. The hole is designed to receive an anchor bolt, and the measuring jig is used to easily and accurately determine the relative position of each hole. This measuring jig includes multiple installation bodies, a string-like body connecting the installation bodies at an arbitrary distance, a azimuth angle meter attached to each installation body, and a distance detection means for detecting the tensioned length of the string-like body between the installation bodies. Each installation body is also equipped with a level. The conical portion of the installation body is embedded in the hole formed on the top surface of the pier for installing the bearing device, and the installation body is placed in the hole with its upper end protruding upward from the hole. The installation body is positioned so that it is horizontal while observing the level, so that the center of the installation body in a plan view is the center of the hole in a plan view. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-156755 Summary of the Invention [Problem to be solved by the invention]

[0006] In order to install anchor bolts vertically in the substructure, it is desirable to set the cylindrical formwork more vertically when punching the box of the substructure. To achieve this, it is effective to use a spirit level, as mentioned above. However, although the cylindrical formwork is fixed when concrete is poured, the formwork is subject to external forces caused by pouring the concrete and tends to tilt, making it difficult to control the verticality of the cylindrical formwork using a spirit level. The measuring jig in Patent Document 1 is not intended for controlling this verticality, and would not be suitable for controlling the verticality of a cylindrical formwork.

[0007] On the other hand, at construction sites, there are cases where cylindrical members such as duct members are installed horizontally, and in such cases, it is important to control the horizontality of the cylindrical members.

[0008] The present disclosure aims to provide a centering tool that can be used to manage the posture of a tubular member such as a tubular formwork. [Means for solving the problem]

[0009] One aspect of the present disclosure is a first end member and a second end member arranged along a linear first axis; a plurality of expansion / contraction arms that expand and contract around the first axis in a direction perpendicular to the first axis, each expansion / contraction arm being connected to the first end member and the second end member; a plurality of abutment members provided on the outside of the expansion / contraction arm around the first axis, each abutment member being movable around a second axis intersecting the first axis; an elastic member provided to expand the expansion / contraction arm; Equipped with The abutment member is provided so that the orientation of the abutment surface facing outward of the abutment member changes with the movement around the second axis. Centering tool to provide.

[0010] When the centering device having the above configuration is placed inside a tubular member, the elastic force of the elastic member causes the multiple expansion / contraction arms to expand in a direction perpendicular to the first axis, and the abutment member is pressed against the inner surface of the tubular member. At this time, the abutment member is configured so that the orientation of the abutment surface changes with movement around the second axis. Therefore, abutment of the abutment member urges the first end member and the second end member to be positioned on the central axis of the tubular member, and the first axis generally coincides with the central axis of the tubular member. Therefore, using this first axis as the central axis of the tubular member, it is possible to control the posture of the tubular member.

[0011] Preferably, the expansion / contraction arm has a first arm member extending to the first end member and a second arm member extending to the second end member. In this case, the abutment member is preferably provided at a joint between the first arm member and the second arm member. With this configuration, the expansion / contraction arm can be expanded / contracted in a direction perpendicular to the first axis, and the abutment member can be more suitably pressed against the inner surface of the tubular member when the centering device is placed inside the tubular member.

[0012] Preferably, the abutment member is provided at the joint portion so that its width in the second axial direction is substantially constant when it moves about the second axis. With this configuration, when the centering device is placed inside the tubular member, the abutment member can be more suitably pressed against the inner surface of the tubular member, so that the first axis can be made to coincide with or as close as possible to the central axis of the tubular member.

[0013] Preferably, the centering device further includes a fixing means for fixing the first end member to a rod-shaped member extending along the first axis. In this case, the second end member is preferably movable relative to the rod-shaped member. This makes it possible to use a rod-shaped member with its axis as the first axis, and to more easily control the posture of the tubular member when the centering device is placed inside the tubular member.

[0014] Preferably, the first axis intersects the second axis at a right angle. With this configuration, by moving the abutting member, it is possible to more easily make the first axis coincide with or as close as possible to the axis of the tubular member.

[0015] The present disclosure also resides in a method of using the aforementioned centering tool, the method comprising: attaching the centering tool to the rod-shaped member so that the rod-shaped member extends along the first axis; a step of placing the centering tool inside the tubular member against the elastic force of the elastic member, and abutting the abutment member against the inner surface of the tubular member by the elastic force of the elastic member; It is good to include. [Effects of the Invention]

[0016] According to the above aspect of the present disclosure, since the above configuration is provided, the above-described centering tool can be used to manage the posture of a tubular member. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view of a centering tool according to one embodiment. [Figure 2] FIG. 2 is a front view of the centering tool of FIG. [Figure 3] FIG. 3 is a top view of the centering tool of FIG. [Figure 4] FIG. 4 is a perspective view showing a state in which a centering tool is attached to a rod-shaped member so that the rod-shaped member extends along the axis of the centering tool of FIG. [Figure 5]5 is a cross-sectional view of a portion of the centering tool of FIG. 1 taken along line VV of FIG. 3, showing a rod-shaped member disposed along the axis of the centering tool. [Figure 6] FIG. 6 is a perspective view showing the centering tool of FIG. 1 in a stored state. [Figure 7] FIG. 7 is a schematic diagram showing the movement of the contact member in the centering device of FIG. [Figure 8] FIG. 8 is a diagram showing the centering tool of FIG. 1 attached to a rod-shaped member and placed inside a tubular member. [Figure 9] FIG. 9 shows a part of a bridge under construction. [Figure 10] FIG. 10 shows four cylindrical formworks arranged side by side and temporarily fixed with square timbers when pouring concrete for the bridge pier shown in FIG. [Figure 11] FIG. 11 is a diagram showing the inside of one of the cylindrical molds shown in FIG. [Figure 12] FIG. 12 shows a cross-sectional view of the cylindrical formwork of FIG. 11 cut along an imaginary plane along its central axis. [Figure 13] FIG. 13 is a flow chart illustrating a method of using the centering tool of FIG. [Figure 14] FIG. 14 shows a modified example of the abutment member in the centering device of FIG. [Figure 15] FIG. 15 shows a further modification of the abutment member in the centering device of FIG. [Figure 16] FIG. 16 shows a modified example of the arm member of the expansion / contraction arm in the centering device of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0019] A centering tool 10 according to one embodiment will be described with reference to FIGS. 1 to 8. FIG. 1 is a perspective view of the centering tool 10. FIG. 2 is a front view of the centering tool 10. FIG. 3 is a top view of the centering tool 10. FIG. 4 is a perspective view showing the centering tool 10 attached to a rod-shaped member R so that the rod-shaped member R extends along an axis (hereinafter referred to as a first axis) 10A of the centering tool 10. FIG. 5 is a cross-sectional view of a portion of the centering tool 10 taken along line VV in FIG. 3, showing the rod-shaped member R disposed along the linear first axis 10A of the centering tool 10. Note that FIG. 5 does not show the fixing screw 22 in cross section. FIG. 6 is a perspective view showing the centering tool 10 in a stored state. FIG. 7 is a schematic diagram showing the movement of the backing plate member 12, which is an abutting member of the centering tool 10. FIG. 8 is a view showing the centering tool 10 attached to the rod-shaped member R disposed within a tubular member P. In the present disclosure, the tubular member P is a cylindrical member here, but is not limited to this, and can be various members that define an internal space having a central axis, preferably a straight central axis, and for example, is not limited to those having both ends open, but may be those having one end closed, and may be those whose diameter, part or all of which, changes in the axial direction, for example, those having a conical shape or the shape of a part thereof.

[0020] The centering tool 10 comprises two end members 14, four expansion / contraction arms 16, four backing plate members 12, and two tension coil springs 18. These are connected and fixed to each other with screws (bolts) and nuts, but can mechanically move relative to each other when subjected to an external force, such as the elastic force of the tension coil springs 18.

[0021] The two end members 14 are substantially identical. In the centering tool 10 shown in FIG. 1, the two end members 14 are used in an upside-down arrangement facing each other. One of the two end members 14, the one located on the upper side in FIG. 2, is referred to as the first end member 14A, and the other end member 14 is referred to as the second end member 14B, although the relationship between them may be reversed. The first end member 14A is provided with a fixing screw 22 as a fixing means for fixing the first end member 14 to the rod-shaped member R. However, the second end member 14B does not have this fixing screw 22, although it may have one. When attaching the centering tool 10 to the rod-shaped member R, the fixing screw 22 of either the first end member 14A or the second end member 14B is used, and the fixing screw 22 of the other end member is not used.

[0022] The end member 14 has a through hole 24 extending along the linear first axis 10A. The through hole 24 is formed in a cylindrical portion 26. The cylindrical portion 26 has an outer peripheral surface 28 provided with radially extending portions 32 extending radially from the outer peripheral surface 28. The end member 14 has four radially extending portions 32. The four radially extending portions 32 are spaced apart from one another at 90° intervals around the first axis 10A. Therefore, except for the configuration of the fixing screws 22 and their associated screw holes, the end member 14 is formed with 90° rotational symmetry around the first axis 10A. In this way, when the number of radially extending portions 32 is n, the end member 14 is formed with n-fold rotational symmetry. The number of radially extending portions 32 in the end member 14 is not limited to four and may be, for example, three or more.

[0023] The radially extending portion 32 is a plate-shaped portion. The radially extending portion 32 is provided on the cylindrical portion 26 so that its thickness direction extends in a direction perpendicular to the first axis 10A. The radially extending portion 32 is formed so that its length in the direction along the first axis 10A (first axis direction) is shorter than the overall length of the end member 14, but is not limited to this. The tip 32a of the radially extending portion 32 is formed in a substantially semicircular shape. The radially extending portion 32 is formed with a through-hole 32h for attaching the expansion / contraction arm 16 and a through-hole 32s for attaching the tension coil spring 18 (see FIG. 5, for example).

[0024] The end member 14 can be made from various materials. Here, the end member 14 is made from resin, but it may be made from other materials, such as metal. In the end member 14, the cylindrical portion 26 and the radially extending portion 32 are integrally formed. Here, the end member 14 including the cylindrical portion 26 and the radially extending portion 32 is formed using a so-called 3D printer. However, the present disclosure does not exclude the end member 14 being made by other methods or means or being configured by assembling multiple parts.

[0025] The first end member 14A and the second end member 14B are arranged along a linear first axis 10A. Preferably, the axis of the through-hole 24 of the first end member 14A and the axis of the through-hole 24 of the second end member 14B are aligned approximately with the first axis 10A. Therefore, as shown in FIGS. 1 and 4, in the centering device 10, the through-hole 24 of the first end member 14A and the through-hole 24 of the second end member 14B are aligned linearly, allowing a linear rod-shaped member R to be inserted therethrough. Here, the rod-shaped member R is a member with a circular cross section, but this is not limiting. Preferably, the through-hole 24 has a diameter slightly larger than the outer diameter of the rod-shaped member R.

[0026] As shown in Figures 4 and 5, when a rod-shaped member R is inserted into the through-hole 24 of the first end member 14A, a fixing screw 22 (see particularly Figures 2, 3, and 5) is provided to pass through the outer circumferential surface 28 of the first end member 14A into the through-hole 24, and the tip of the fixing screw 22 is screwed in so as to press against the rod-shaped member R, thereby fixing the first end member 14A to the rod-shaped member R. Fixing the first end member 14A to the rod-shaped member R is not limited to using the fixing screw 22, but may be performed using other tools, or may be performed by, for example, approximating the outer diameter of the rod-shaped member R to the inner diameter of the through-hole 24 and utilizing friction therebetween. Note that although the threaded hole for attaching the fixing screw 22 is formed in the first end member 14A, it may also be formed in the second end member 14B.

[0027] The four expansion / contraction arms 16 are the same member and have the same configuration. Note that in the centering device according to the present disclosure, the number of expansion / contraction arms 16 is not limited to four and may be any number, such as three, five, six, etc. Here, the number of expansion / contraction arms 16 is the same as the number of radial extensions 32 on the end member 14.

[0028] In the centering tool 10, the expansion / contraction arms 16 are configured to expand and contract in a direction perpendicular to the axis of the centering tool 10, i.e., the first axis 10A. Each expansion / contraction arm 16 is connected to a first end member 14A and a second end member 14B. The multiple expansion / contraction arms 16 are identical members having the same configuration as described above, and are arranged to have 90-degree rotational symmetry around the first axis 10A. In this way, when the number of expansion / contraction arms 16 is m, the multiple expansion / contraction arms 16 are arranged to have m-fold rotational symmetry. However, the arrangement of the multiple expansion / contraction arms 16 is not limited to this. The technology of the present disclosure allows various arrangements that allow the central axis of the multiple expansion / contraction arms 16 to substantially coincide with the first axis 10, i.e., to remain substantially the first axis 10, when the multiple expansion / contraction arms 16 perform expansion / contraction movements (see FIG. 8 ).

[0029] The expansion / contraction arm 16 includes two arm members 40, specifically a first arm member 40A extending to the first end member 14A and a second arm member 40B extending to the second end member 14B. The two arm members 40 have the same configuration and are rod-shaped members each having a linear axis 40c (see FIG. 2). The majority of the arm member 40 has a substantially rectangular cross section. The arm member 40 has two plate-shaped portions 44, 46 forming a bifurcated base end 42, a one-sided plate-shaped portion 50 extending along the axis 40c of the arm member 40 at a position offset from the axis 40c and forming a tip end 48, and an intermediate portion 52 extending between the base end 42 and the tip end 48. The base end portion 42 has a through-hole 42h that passes through the two plate-shaped portions 44, 46, and the tip end portion 48 has a through-hole 50h that passes through the plate-shaped portion 50.

[0030] The arm member 40 can be made from various materials. Here, the arm member 40 is made from resin, but it may also be made from other materials, such as metal. Here, the arm member 40 is formed using a so-called 3D printer. However, the present disclosure does not exclude the arm member 40 being made by other methods or means or being configured by assembling multiple parts.

[0031] The first arm member 40A, which is one of the arm members 40, extends to and is connected to the first end member 14A. The radially extending portion 32 of the first end member 14A is inserted between the plate-like portions 44, 46 of the bifurcated base end portion 42 of the first arm member 40A, and screws are inserted into the through-holes 32h, 42h that are aligned to pass through the plate-like portions 44, 46 and then nuts are screwed onto the screws, thereby connecting the first arm member 40A to the first end member 14A. Similarly, the second arm member 40B, which is the other arm member 40, extends to and is connected to the second end member 14B. The second arm member 40B is connected to the second end member 14B by inserting the corresponding radially extending portion 32 of the second end member 14B between the plate-shaped portions 44, 46 of the bifurcated base end portion 42 of the second arm member 40B, inserting screws into the through holes 32h, 42h that are aligned to pass through them, and screwing nuts onto the screws.

[0032] Since the two end members 14 are the same member and the four expansion / contraction arms 16 are the same member, the distance La from the through hole 32h at the first end connection portion between the first end member 14A and the first arm member 40A to the first axis 10A is the same as the distance from the through hole 32h at the second end connection portion between the second end member 14B and the second arm member 40B to the first axis 10A. This distance or length is referred to as the arm distance La (see FIG. 5).

[0033] The one-side plate portions 50 of the tip ends 48 of the first and second arm members 40A, 40B are overlapped so as to complement each other's cutout portions 50c, and the tip ends 48 of the first and second arm members 40A, 40B are connected to each other by inserting screws into the aligned through holes 50h and threading nuts onto the screws. Here, this connection portion between the first and second arm members 40A, 40B is referred to as joint portion J. The backing plate member 12 is attached to this joint portion J. At joint portion J, the backing plate member 12 is attached to the tip ends 48 of the first and second arm members 40A, 40B such that the holding portion 60 of the backing plate member 12 is sandwiched between the one-side plate portions 50.

[0034] The backing plate member 12 is an example of an abutment member. In the centering device 10, the number of backing plate members 12 is the same as the number of expansion / contraction arms 16, which is four. However, the number of backing plate members 12 may be other than four, and is preferably more than one, and more preferably three or more. Furthermore, the number of backing plate members 12 may be different from the number of expansion / contraction arms 16.

[0035] The backing plate member 12 has an abutment body portion 64 having an abutment surface 62 which is its outer surface, and the aforementioned holding portion 60 which extends to the back side of the abutment body portion 64, i.e., on the opposite side from the abutment surface 62. The holding portion 60 is provided via a linear step portion 68 on an inner surface 66 of the abutment body portion 64 opposite the abutment surface 62. The holding portion 60 is thin plate-shaped, and its tip 60a has a substantially semicircular shape.

[0036] The holding portion 60 has a through hole 60h. When the holding portion 60 of the backing plate member 12 is connected to the joint portion J, the through hole 60h aligns with the through holes 50h of the first and second arm members 40A, 40B, screws are inserted into the through holes 60h, and nuts are screwed onto the screws. At this time, the axis of the through holes 50h, 60h or the axis of the screw becomes the axis that serves as the reference for the movement of the backing plate member 12, i.e., the second axis JA.

[0037] The abutment body 64 is a generally plate-shaped member and is configured to be curved so that the abutment surfaces 62 are convexly curved. Here, the curvature of the abutment surfaces 62 is determined with reference to the first axis 10A in the centering device 10. As shown in FIG. 3 , the convex curved shape of the abutment surfaces 62 is designed so that, when the centering device 10 is viewed in a direction along the first axis 10A, i.e., from the first axis direction, all of the abutment surfaces 62 are aligned on the same circumference centered on the first axis 10A. However, the reference for the convex curvature of the abutment surfaces 62 does not have to be the first axis 10A. For example, the reference for the convex curvature of the abutment surfaces 62 may be an imaginary line parallel to the first axis 10A and located away from the first axis 10A.

[0038] The contact surface 62 is designed not to curve around the second axis JA, that is, to be straight. Therefore, as shown in Fig. 2, when the backing plate member 12 is viewed in a direction along the second axis JA, that is, from the second axial direction, the contact surface 62 extends straight. In Figs. 1 to 4, the backing plate member 12 is shown so that the contact surface 62 of the backing plate member 12 is parallel to the first axis 10A.

[0039] In this way, the contact surface 62 of the backing plate member 12 is convexly curved in the circumferential direction of the centering tool 10 around the first axis 10A, and is non-curved, i.e., extends straight, in the rotation direction of the backing plate member 12 around the second axis JA. In other words, the backing plate member 12 is configured so that the contact surface 62 can be made parallel to the first axis 10A by moving it around the second axis JA.

[0040] The contact surface 62, which can become parallel to the first axis 10A as the backing plate member 12 moves about the second axis JA, preferably has an area equal to or greater than a predetermined area. The circumferential length L1 (see FIG. 3) of the contact surface 62 of the backing plate member 12 about the first axis 10A (hereinafter referred to as the circumferential length) is preferably equal to or greater than a first predetermined length. Furthermore, the length L2 (see FIG. 2) of the contact surface 62 of the backing plate member 12 in the rotation direction about the second axis JA (hereinafter referred to as the rotation direction length) is preferably equal to or greater than a second predetermined length. The circumferential length L1 and the rotation direction length L2 can be determined arbitrarily. The circumferential length L1 and the rotation direction length L2 are preferably determined based on both the inner diameter of the tubular member P and a technique for roughly aligning the axis 10A with the central axis of the tubular member P by placing the centering tool 10 inside the tubular member P and abutting the backing plate member 12 against its inner surface Pi, as described below. In particular, these circumferential length L1 and rotational length L2 are preferably determined so as to enable the axis 10A to be approximately aligned with the central axis of the tubular member P by placing the centering device 10 inside the tubular member P and abutting the abutment surface 62 of the backing plate member 12 against its inner surface Pi.

[0041] An inner surface 66 of the abutment body portion 64 opposite to the abutment surface 62 is curved concavely. However, the inner surface 66 does not have to be curved concavely.

[0042] The backing plate member 12 can be made of various materials. Here, the backing plate member 12 is made of resin, but it may be made of other materials, such as metal. The backing plate member 12 is also integrally molded using a so-called 3D printer. However, this disclosure does not exclude the backing plate member 12 being made by other methods or means or being constructed by assembling multiple parts. It is preferable that the abutment surface 62 has a certain degree of slipperiness at the opening or inner surface Pi of the tubular member P.

[0043] The tension coil spring 18 is an example of an elastic member. The tension coil spring 18 is arranged to expand the expansion / contraction arm 16. Two tension coil springs 18 are used in the centering device 10. These tension coil springs 18 are arranged at rotationally symmetric positions on either side of the first axis 10A. This is so that the tension coil springs 18 exert a balanced elastic force on the centering device 10. The number of tension coil springs 18 is not limited to two, and may be one, three, or more. However, it is preferable to determine the number or arrangement of the tension coil springs 18 so that the elastic force of the tension coil springs 18 exerts a balanced force on the centering device 10.

[0044] The tension coil spring 18 is provided so as to exert an elastic force on the first end member 14A and the second end member 14B in a direction narrowing the gap between the first end member 14A and the second end member 14B, thereby expanding the expansion / contraction arm 16. Here, both ends of the tension coil spring 18 are hooked into through holes 32s for attaching the tension coil spring 18, which are formed in opposing radially extending portions 32 of the first end member 14A and the second end member 14B that overlap in the direction of the first axis 10A.

[0045] As shown in Figure 5, the through hole 32s of the radially extending portion 32 for attaching the tension coil spring 18 is formed at a position closer to the first axis 10A than the through hole 32h of the radially extending portion 32 for connecting the arm member 40 to the end member 14. In other words, the arm distance L1 described above from the through hole 32h to the first axis 10A is longer than the distance Lb from the through hole 32s to the first axis 10A (La > Lb in Figure 5). Therefore, when the joint portion J is in a position where it can abut, as will be described later, the tension coil spring 18 is located closer to the first axis 10A than the extension arm 16, and does not affect the operation of the extension arm 16, for example, the abutment of the abutment surface 62.

[0046] The elastic member of the centering device of the technology of the present disclosure is not limited to the tension coil spring 18. Various elastic members that function to expand the expansion / contraction arm 16, i.e., to expand the expansion / contraction arm 16 in a direction perpendicular to the first axis, can be used as the elastic member. For example, the elastic member may be an elastic body that is directly provided on the expansion / contraction arm 16.

[0047] The centering tool 10 having the above configuration operates as follows.

[0048] The expansion / contraction arm 16 expands and contracts in a direction perpendicular to the first axis 10A. In each of the expansion / contraction arms 16, the first arm member 40A and the second arm member 40B expand and contract along a plane (imaginary plane) that includes the first axis 10A. The backing plate member 12 provided at the joint J of the first and second arm members 40A, 40B can move around the second axis JA along that imaginary plane. One of these imaginary planes is a plane parallel to the paper surface of FIG. 2 and that includes the first axis 10A. As the expansion / contraction arm 16 expands and contracts, the distance between the first end member 14A and the second end member 14B changes along the first axis 10A.

[0049] As the expansion / contraction arm 16 expands and contracts, the joint portion J, to which the backing plate member 12 is attached, is selectively positioned between an abutment-ready position where the distance to the first axis 10A is longer than the arm distance La, and a storage position where the distance to the first axis 10A is equal to or shorter than the arm distance La. FIGS. 1 to 5, 7, and 8 show the centering device 10 or a portion thereof in which the joint portion J of the expansion / contraction arm 16 is in the abutment-ready position where the distance to the first axis 10A is longer than the arm distance La (see FIG. 5). When in the abutment-ready position, the joint portion J is preferably positioned farther from the first axis 10A than all of the first and second end members 14A, 14B, i.e., outward, as the expansion / contraction arm 16 expands in the direction perpendicular to the first axis 10A due to the elastic force of the tension coil spring 18, exceeding the width of the first and second end members 14A, 14B in the direction perpendicular to the first axis 10A. Fig. 6 shows the centering tool 10 in a stored state where the joint J of the expansion / contraction arm 16 is positioned such that the distance to the first axis 10A is equal to or less than the arm distance La. The joint J can be selectively positioned between the abutment state shown in Fig. 1, an example of which is shown in Fig. 6, and the stored state. An operator can manually change the position of the joint J by adjusting the distance between the first end member 14A and the second end member 14B or the expansion / contraction of the expansion / contraction arm 16, for example, against the elastic force of the tension coil spring 18.

[0050] As shown in FIG. 7, the backing plate member 12 can move along the aforementioned imaginary plane around the axis of the joint portion J, i.e., the second axis JA. This movement changes the orientation of the contact surface 62 of the backing plate member 12 facing outward. FIG. 7 shows the movement of the backing plate member 12 around the second axis JA. In FIG. 7, the first axis 10A extends into the plane of the paper, and the second axis JA extends perpendicular to the plane of the paper. As is clear from FIG. 7, the movement of the backing plate member 12 around the second axis JA changes the orientation of the contact surface 62, and therefore the length of the contact surface 62 in the direction of the first axis 10A changes (for example, length Lc≠Ld).

[0051] 8, when the centering tool 10 is placed inside the tubular member P, the joint portion J is positioned at any position in a contactable state, and the elastic force of the tension coil spring 18 is released, the backing plate member 12, i.e., each of the contact surfaces 62, is inclined according to the inner surface Pi of the tubular member P and can be pressed and contacted. As described above, the multiple expansion / contraction arms 16 are attached to the end members 14A, 14B so as to have m-fold rotational symmetry, where m is the number of expansion / contraction arms 16. Therefore, when the multiple expansion / contraction arms 16 perform expansion / contraction operations, the central axes of the multiple expansion / contraction arms 16 substantially remain the first axis 10. Therefore, when the centering tool 10 is placed inside the tubular member P, the contact surface 62 of the backing plate member 12 can be flexibly and firmly contacted against the inner surface Pi of the tubular member P, and the first axis 10A of the centering tool 10 can be made to coincide with or as close as possible to the central axis of the tubular member P.

[0052] However, although the contact surface 62 of the backing plate member 12 extends in a direction intersecting the aforementioned imaginary plane, the backing plate member 12 can essentially only move around the second axis JA of the joint part J. In other words, the backing plate member 12 is configured so that it can move around the second axis JA of the joint part J, with a substantially constant width in the direction intersecting the aforementioned imaginary plane. Note that the backing plate member 12 is capable of various movements within the range of play between the parts, but it is preferable that this play be small.

[0053] 4, a rod-shaped member R is inserted into the through-holes 24 of the first end member 14A and the second end member 14B of the centering tool 10, which moves in this manner. The rod-shaped member R is fixed to the first end member 14A with a fixing screw 22. However, the second end member 14B is not fixed to the rod-shaped member R and is movable relative to the rod-shaped member R, i.e., is slidable.

[0054] An example of how to use this centering tool 10 will now be described.

[0055] Figure 9 shows a bridge 80 under construction. In order to install a bridge girder 84 on a pier 82, anchor bolts 86 are installed in the pier 82 after concrete is poured. To secure a place to attach this anchor bolt 86, a cylindrical formwork 88 is set up vertically as a box cutout when pouring concrete into the pier 82. To set up this cylindrical formwork 88 vertically, a centering tool 10 is used. In this case, the cylindrical formwork 88 is a spiral pipe, which is an example of a cylindrical member P.

[0056] Figure 10 shows four cylindrical formwork pieces 88 lined up and temporarily fixed with timbers 90 and reinforcing bars 91. Figure 11 shows the interior of one of the cylindrical formwork pieces 88 shown in Figure 10, and Figure 12 shows a cross-sectional view of the cylindrical formwork piece 88 of Figure 11 cut along an imaginary plane along its central axis, that is, a cross-sectional view of the cylindrical formwork piece 88 cut along line XII-XII in Figure 3. However, Figure 12 does not show the fixing screws 22 in cross section. In Figures 10 to 12, a rod-shaped member R with two centering tools 10 attached at a distance from each other is inserted into the cylindrical formwork piece 88.

[0057] The centering tool 10 may be attached (used) according to the procedure of the method of using the centering tool shown in FIG. 13. First, the centering tool 10 is attached to the rod-shaped member R so that the rod-shaped member R extends along the first axis 10A (step S1). Here, two centering tools 10 are attached to the rod-shaped member R. The number of centering tools 10 attached to the rod-shaped member R may be one, but preferably multiple. Next, the centering tool 10 is placed inside the tubular member P against the elastic force of the tension coil spring 18, which is an elastic member, and the backing plate member 12 is brought into contact with the inner surface Pi of the tubular member P by the elastic force of the tension coil spring 18 (step S2). In step S2, the contact surface 62 of the backing plate member 12 may be placed against the opening of the tubular member P, and the contact surface 62 may be slidably pushed into the tubular member P to place the centering tool 10 inside the tubular member P. Alternatively, the centering member 10 may be disposed inside the tubular member P by contracting the expansion / contraction arm 16 in a direction perpendicular to the first axis 10A against the elastic force of the tension coil spring 18, which is an elastic member. Then, the elastic force of the tension coil spring 18 can cause the abutment surface 62 of the backing plate member 12 to abut against the inner surface Pi of the tubular member P. In this way, the axis of the rod-shaped member R of the centering tool 10 disposed inside the tubular member P, i.e., the first axis 10A, roughly coincides with the central axis of the tubular member P. Therefore, the rod-shaped member R can be used as the axis or shaft member of the tubular member P.

[0058] 10, a spirit level 92 is attached to the top of the rod-shaped member R. By looking at this spirit level 92 when pouring concrete, the worker can easily manage the posture (in other words, manage the tilt) of the cylindrical formwork 88. Note that the spirit level is not limited to the spirit level 92 with an air bubble, and may be, for example, a digital spirit level, or any of various measuring means that measures the tilt by receiving a beam of light or the like from a remote location.

[0059] In this example of use of the centering tool 10, the centering tool 10 was used to vertically stand the cylindrical formwork 88, which is the cylindrical member P. However, the centering tool 10 can be used for other purposes as well. For example, the centering tool 10 can be used to manage the posture of a cylindrical member when installing the cylindrical member horizontally, such as when installing duct members horizontally at a construction site. Note that managing the posture of a cylindrical member is not limited to managing the "vertical" posture of the cylindrical member or managing its "horizontal" posture, but can also include managing its "diagonal" posture.

[0060] Below, some of the characteristic features of the centering tool 10 having the above-described configuration and the resulting effects will be described.

[0061] The centering device 10 includes a first end member 14A and a second end member 14B arranged along a linear first axis 10A, a plurality of expansion / contraction arms 16 that expand and contract about the first axis 10A in a direction perpendicular to the first axis 10A, each connected to the first end member 14A and the second end member 14B, a plurality of backing plate members 12 provided outside the expansion / contraction arms 16 about the first axis 10A, and a tension coil spring 18 provided to expand the expansion / contraction arms 16. Each backing plate member 12 is movable about a second axis JA that intersects the first axis 10A. The backing plate members 12 are provided on the expansion / contraction arms 16 such that the orientation of the abutment surface 62 facing outward of the backing plate member 12 changes with movement about the second axis JA.

[0062] When the centering tool 10 having the above configuration is placed inside a tubular member P, the elastic force of the tension coil spring 18 causes the multiple expansion / contraction arms 16 to expand in a direction perpendicular to the first axis 10A, and the abutment surface 62 of the backing plate member 12 is pressed against the inner surface Pi of the tubular member P. At this time, the backing plate member 12 is configured so that the orientation of the abutment surface 62 facing outward of the backing plate member 12 changes as the backing plate member 12 moves about the second axis JA. Therefore, the abutment of the backing plate member 12 urges the first end member 14A and the second end member 14B to be positioned on the central axis of the tubular member P, and the first axis 10A roughly coincides with the central axis of the tubular member P. Therefore, by using this first axis 10A as the central axis of the tubular member P, it becomes possible to more easily control the posture of the tubular member P.

[0063] The expansion / contraction arm 16 has a first arm member 40A extending to the first end member 14A and a second arm member 40B extending to the second end member 14B. The backing plate member 12 is provided at a joint J between the first arm member 40A and the second arm member 40B. With this configuration, the expansion / contraction arm 16 can be expanded / contracted in a direction perpendicular to the first axis 10A, and when the centering device 10 is placed inside the tubular member P, the abutment surface 62 of the backing plate member 12 can be more suitably pressed against the inner surface Pi of the tubular member P.

[0064] Furthermore, the backing plate member 12 is provided at the joint portion J so that its width in the direction of the second axis JA is substantially constant when it moves around the second axis JA. With this configuration, when the centering tool 10 is placed inside the tubular member P, the backing plate member 12 can be more suitably pressed against the inner surface Pi of the tubular member P, and the first axis 10A can be made to substantially coincide with the central axis of the tubular member P, that is, to coincide with or come as close as possible to the central axis of the tubular member P.

[0065] Furthermore, the centering tool 10 has a fixing screw 22 as a fixing means for fixing the first end member 14A to the rod-shaped member R extending along the first axis 10A. The second end member 14B is movable relative to the rod-shaped member R. This makes it easier to control the posture of the tubular member P using the centering tool 10, with the axis of the rod-shaped member R set as the first axis 10A.

[0066] The first axis 10A intersects with the second axis JA at a right angle. With this configuration, when the centering tool 10 is placed inside the tubular member P, the movement of the backing plate member 12 makes it easier to align the first axis 10A with the axis of the tubular member P or to bring it as close as possible to the axis of the tubular member P.

[0067] The centering tool 10 can be modified in various ways.

[0068] 14, for example, both ends of the backing plate member 12M1 in the direction of the first axis 10A may have inwardly rounded portions 94. This makes it possible to preferably prevent the backing plate member 12 from being caught unexpectedly on the opening of the tubular member P when the centering tool 10 is inserted into or removed from the tubular member P.

[0069] 15 shows a backing plate member 12M2 as a further modified example. In this backing plate member 12M2, a locking protrusion 96 is provided on the edge of the abutment surface 62 of the backing plate member 12M2 so that the backing plate member 12M2 can be hooked onto the edge of the opening of the tubular member P to hold the centering tool.

[0070] 16 shows a modified arm member 40M of the expansion / contraction arm 16. This arm member 40M is provided with a screw-type variable mechanism 98 so that the length of the arm member 40M can be varied.

[0071] Although the above-described embodiments and modifications thereof have been described, the present disclosure is not limited thereto. Various substitutions and modifications are possible without departing from the spirit and scope of the present disclosure, which are defined by the claims of the present application.

[0072] For example, in the centering tool 10 described above, the rod-shaped member R was detachable from the end member 14. However, the rod-shaped member R may be completely fixed to or integral with one of the end members 14 of the centering tool 10. For example, the cylindrical portion 26 of one end member 14 may be a solid portion, or may be a rod-shaped portion that extends into the through-hole 24 of the other end member 14. [Explanation of symbols]

[0073] 10 Centering tool 10A axis (1st axis) 12, 12M1, 12M2 Backing plate member (contact member) 14 End member 14A First end member 14B Second end member 16 Expandable arm 18 Tension coil spring (elastic member) 22 Fixing screw 26 Cylindrical part 32 Radial extension 40, 40M arm parts 40A First arm member 40B Second arm member 64 Contact body part 60 Holding part 62 Contact surface JA axis (second axis)

Claims

1. a first end member and a second end member arranged along a linear first axis, the first end member and the second end member being configured so that the second end member is movable relative to the first end member along a rod-shaped member or rod-shaped portion that is coaxial with the first axis and extends across the first end member and the second end member; a plurality of expansion / contraction arms that expand and contract about the first axis in a direction perpendicular to the first axis, each expansion / contraction arm being connected to the first end member and the second end member; a plurality of abutment members provided on the outside of the expansion / contraction arm around the first axis, each abutment member being movable around a second axis intersecting the first axis; an elastic member provided to expand the expansion / contraction arm; Equipped with The abutment member is provided such that an orientation of an abutment surface facing outward of the abutment member changes in accordance with the movement around the second axis. Centering tool.

2. A first end member and a second end member arranged along a linear first axis, the first end member and the second end member each having a through hole along the first axis; a plurality of expansion / contraction arms that expand and contract about the first axis in a direction perpendicular to the first axis, each expansion / contraction arm being connected to the first end member and the second end member; a plurality of abutment members provided on the outside of the expansion / contraction arm around the first axis, each abutment member being movable around a second axis intersecting the first axis; an elastic member provided to expand the expansion / contraction arm; Equipped with The abutment member is provided such that an orientation of an abutment surface facing outward of the abutment member changes in accordance with the movement around the second axis. Centering tool.

3. A first end member and a second end member arranged along a linear first axis; a plurality of expansion / contraction arms that expand and contract about the first axis in a direction perpendicular to the first axis, each expansion / contraction arm being connected to the first end member and the second end member; a plurality of abutment members provided on the outside of the expansion / contraction arm around the first axis, each abutment member being movable around a second axis intersecting the first axis; an elastic member provided to expand the expansion / contraction arm; Equipped with The abutment member is provided such that a direction of an abutment surface facing outward of the abutment member changes in accordance with the movement around the second axis, The abutting member has a locking protrusion for hooking the abutting member onto the edge of the opening of the tubular member. Centering tool.

4. the extension / contraction arm has a first arm member extending to the first end member and a second arm member extending to the second end member; the abutment member is provided at a joint portion between the first arm member and the second arm member; A centering tool according to any one of claims 1 to 3.

5. The expansion / contraction arm has a first arm member extending to the first end member and a second arm member extending to the second end member, the abutment member is provided at a joint portion between the first arm member and the second arm member, the abutment member is provided at the joint portion so that a width in the second axial direction is substantially constant when the abutment member moves around the second axis; A centering tool according to any one of claims 1 to 3.

6. The device further includes a fixing means for fixing the first end member to a rod-shaped member extending along the first axis, the second end member is movable relative to the rod member; A centering tool according to any one of claims 1 to 3.

7. The first axis intersects the second axis at a right angle. A centering tool according to any one of claims 1 to 3.

8. A method of using the centering tool according to any one of claims 1 to 3, comprising the steps of: attaching the centering tool to the rod-shaped member so that the rod-shaped member extends along the first axis; a step of placing the centering tool inside the tubular member against the elastic force of the elastic member, and abutting the abutment member against the inner surface of the tubular member by the elastic force of the elastic member; Including, How to use the centering tool.

Images