Paper void pipe removal tool

Abstract

To provide a paper void pipe removal tool that simplifies the work of pulling out a void pipe and is applicable to a relatively large void pipe.SOLUTION: A paper void pipe removal tool has a structure in which an outer rod 10, inserted between a void pipe 2 and surrounding concrete 3, and an inner rod 11, disposed inside the void pipe 2, are arranged parallel to each other with a spacing that allows insertion of a thick-walled portion of the void pipe 2, and are partially connected. The outer rod 10 has, at its insertion-side end, a sharp pointed tip 12 whose thickness gradually decreases, and, at its other end, a base portion 13 for applying a striking force in the axial direction of the outer rod 10. The inner rod 11 has, at the end protruding from the void pipe 2, a handle attachment portion 14 to which a handle 15 for rotating the inner rod 11 around its central axis can be attached.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a removal tool for a paper void tube that is pre-embedded to provide holes or the like in concrete and can be easily removed after the concrete has hardened.

Background Art

[0002] Conventionally, in order to provide holes or the like that penetrate a concrete structure, a cylindrical paper void tube has been installed in a formwork in advance before pouring the concrete, and after the concrete has hardened, the embedded void tube has been removed.

[0003] As shown in FIG. 6(A), the conventional method for removing the void tube is to insert a steel bar formed in a sharp shape with a gradually decreasing thickness at the tip side, such as a burr 52, between the void tube 50 and the surrounding concrete 51, and gradually insert the burr 52 deeper while peeling the void tube 50 from the concrete 51 using the lever principle. As shown in FIG. 6(B), when the burr 52 has been inserted up to the height of the void tube 50, the burr 52 is removed, and as shown in FIG. 6(C), a removal tool 53 fabricated by assembling a single-tube pipe or the like is inserted into this gap portion and wound up. This method has been common.

[0004] The conventional removal tool 53 is composed of a single-tube pipe or the like, and includes two vertical members 55, 56 arranged in parallel with a predetermined separation distance, and a handle member 57 fixed orthogonally to the upper ends of these vertical members 55, 56. The usage method of this removal tool 53 is to insert one vertical member 55 into the gap portion between the void tube 50 and the concrete 51 after removing the burr 52, and position the other vertical member 56 on the inner cavity side of the void tube 50 so as to sandwich the wall thickness portion of the void tube 50 between it and the one vertical member 55. In this state, by rotating the handle member 57 around the axial direction of the vertical members 55, 56, the void tube 50 is peeled off from the concrete 51.

[0005] The removal method using such a removal tool 53 is often used for a relatively large void tube 50 with a diameter of 15 cm or more and a length of 500 mm or more. For a void tube 50 with a smaller diameter and shorter length, hand tools such as those disclosed in Patent Document 1 below, called void removal, are often used. Patent Document 1 below discloses a hand tool for die removal, which is formed by bending a metal round bar twice and in parallel with a portion slightly eccentric from the center of the length as a base, and providing a twist rod insertion hole and a fastening at the base to form a short round bar and a long round bar, and a pointed end portion is provided by shaving the tip of the long round bar outward to make it sharp.

[0006] The method for removing a void tube using this hand tool is to insert the pointed end of the long round bar into the outer peripheral surface in close contact with the void tube, peel off the void tube from the contact portion, and further insert the pointed end of the long round bar to the length of the void tube, sandwich it between the other short round bar, and insert a separately formed twist rod into the twist rod insertion hole provided at the bent base of the main body. If this is strongly twisted, the void tube can be sandwiched and wound around the double parallel round bars of the main body and pulled out.

[0007] In recent years, hand tools have also been commercially available in which a handle bar for twisting is integrally attached to the base end of the double parallel round bars and is made easier to rotate in one direction by a ratchet mechanism.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, the hand tools disclosed in Patent Document 1 and the like can only be applied to relatively small void tubes with a diameter of less than 15 cm and a length of less than 500 mm, and have the drawback of having limitations in the applicable size.

[0010] For relatively large void pipes with a diameter of 15 cm or more and a length of 500 mm or more, since there is no removal tool suitable for them, as described above, as shown in FIG. 6, after performing the insertion operation of the burl 52, a winding operation using the removal tool 53 is performed. Thus, two steps of operations are required, and a great deal of labor and time are required for the extraction operation.

[0011] Therefore, the main object of the present invention is to provide a removal tool for a paper void pipe that simplifies the extraction operation of the void pipe and is applicable to relatively large void pipes.

Means for Solving the Problems

[0012] As the present invention according to claim 1 for solving the above problems, a removal tool used when removing a paper void pipe embedded in concrete, An outer rod part that is arranged in parallel with each other with a separation that allows the wall thickness part of the void pipe to be inserted, and an inner rod part that is arranged on the inner void side of the void pipe are partially connected. The outer rod part has a pointed end part with a gradually decreasing thickness formed at the end on the inserted side, and a pedestal part for applying an impact force in the axial direction of the outer rod part is provided on the other end side. The inner rod part is provided with a handle attachment part to which a handle for rotating the inner rod part around the central axis can be attached at the end on the side protruding from the void pipe. A removal tool for a paper void pipe is provided.

[0013] In the invention described in claim 1 above, the outer rod part and the inner rod part are arranged in parallel with each other with a separation that allows the wall thickness part of the void pipe to be inserted, and have a structure that is partially connected. The outer rod part is a rod part inserted between the void pipe and the surrounding concrete, and the inner rod part is a rod part arranged on the inner void side of the void pipe.

[0014] In order to facilitate the insertion of the outer rod portion between the void tube and the concrete and to facilitate the peeling of the void tube from the concrete, a pointed end portion having a gradually decreasing thickness is formed at the end portion on the insertion side, and a pedestal portion serving as a surface to be struck when an impact force is applied in the axial direction of the outer rod portion is provided on the other end side.

[0015] With the outer rod portion inserted over the entire length of the void tube, the inner rod portion is rotated to peel the outer peripheral surface of the void tube from the concrete. At this time, in order to facilitate the rotation of the inner rod portion, a handle attachment portion to which a handle for rotating the inner rod portion about the central axis can be attached is provided at the end portion of the inner rod portion protruding from the void tube.

[0016] As described above, in the removal tool according to the present invention, after inserting the outer rod portion between the void tube and the concrete, the outer peripheral surface of the void tube can be peeled from the concrete by rotating the inner rod portion in the same state, so there is no need to insert and remove the tool midway, the peeling operation is completed in one step, and the pulling-out operation of the void tube can be simplified. Further, the removal tool according to the present invention is applicable to relatively large void tubes having a diameter of 20 cm or more and a length of 1 m or more.

[0017] As the present invention according to claim 2, there is provided a removal tool for a paper-made void tube according to claim 1, wherein the pointed end portion is formed by bending outward in a U-shape.

[0018] In the invention described in claim 2 above, when the outer rod portion is inserted between the void tube and the concrete, in order to facilitate the peeling of the void tube from the concrete, the pointed end portion is formed by bending outward in a U-shape.

[0019] As the present invention according to claim 3, there is provided a removal tool for a paper-made void tube according to claim 1, wherein the handle attachment portion is composed of a tubular member into which the rod-shaped handle can be fitted and whose axial direction extends in a direction perpendicular to the central axis of the inner rod portion.

[0020] In the invention described in claim 3 above, the mounting structure of the handle for rotating the inner rod portion is shown. Specifically, the handle mounting portion is constituted by a pipe member in which the rod-shaped handle can be inserted and whose axial direction extends in a direction perpendicular to the central axis of the inner rod portion.

[0021] As the invention according to claim 4, there is provided a removing instrument for a paper void tube according to claim 1, wherein the length of the inner rod portion protruding from the void tube is formed longer than that of the outer rod portion.

[0022] In the invention described in claim 4 above, since the length of the inner rod portion protruding from the void tube is formed longer than that of the outer rod portion, it becomes easier to attach and rotate a handle to the handle mounting portion attached to the tip of the inner rod portion.

Effect of the Invention

[0023] As described in detail above, according to the present invention, the operation of pulling out the void tube can be simplified, and it can also be applied to relatively large void tubes.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiment for Carrying Out the Invention

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0026] As shown in FIG. 1, the removal tool 1 according to the present invention is a tool used for removing the buried cylindrical paper void tube 2 installed in a formwork in advance before pouring concrete, in order to provide a void such as a hole penetrating the concrete 3 (including mortar).

[0027] The removal tool 1 according to the present invention is not particularly limited with respect to the size of the void tube 2 that can be removed, but is particularly suitable for removing a relatively large void tube 2 with a diameter of 20 cm or more and a length of 1 m or more. Such a large void tube 2 cannot be dealt with by the small hand tools disclosed in Patent Document 1 etc. As shown in FIG. 6, it was carried out through two steps: a step of inserting a burr 52 between the void tube and the concrete, and a step of winding up the void tube using a separately manufactured removal tool 53. The removal tool 1 according to the present invention is configured to be able to perform the process from inserting the rod member to removing it in one step, whereby the pulling-out operation of the void tube can be greatly simplified.

[0028] Hereinafter, the removal tool 1 will be described in more detail. As shown in FIG. 2, the removal tool 1 has a structure in which an outer rod portion 10 that is inserted between the void tube 2 and the surrounding concrete 3 and an inner rod portion 11 that is arranged on the inner void side of the void tube 2 are partially connected, with a separation that allows the insertion of the thick-walled portion of the void tube 2 and arranged parallel to each other.

[0029] The outer rod portion 10 inserted between the void tube 2 and the concrete 3 is formed with a sharp tip portion 12 whose thickness gradually decreases at the end on the insertion side, and a pedestal portion 13 for applying an impact force in the axial direction of the outer rod portion 10 is provided at the end on the other end side that protrudes from the void tube 2.

[0030] On one hand, the inner rod portion disposed on the inner space side of the void tube 2 is provided with a handle attachment portion 14 at the end portion on the side protruding from the void tube 2, and a handle 15 that can rotate the inner rod portion 11 around the central axis can be attached to the handle attachment portion 14.

[0031] To remove the void tube 2 using this removal tool 1, as shown in Fig. 3(A), by striking the pedestal portion 13 of the outer rod portion 10 with a hammer 20 or the like, the outer rod portion 10 is inserted between the void tube 2 and the concrete 3. As shown in Fig. 3(B), when the insertion reaches the length of the void tube 2, with the state unchanged, the handle 15 is attached to the handle attachment portion 14, and the operator holds the handle 15 by hand and twists it to rotate the inner rod portion 11 around the central axis. As a result, since the outer rod portion 10 rotates around the central axis of the inner rod portion 11, the void tube 2 can be peeled off from the concrete 3.

[0032] Thus, in the removal tool 1 according to the present invention, after the outer rod portion 10 is inserted between the void tube 2 and the concrete 3, with the state unchanged, by rotating the inner rod portion 11, the outer peripheral surface of the void tube 2 can be peeled off from the concrete 3. Therefore, it is not necessary to insert and remove tools midway, the peeling operation is completed in one step, and the pulling-out operation of the void tube 2 can be simplified.

[0033] Explaining the structure of the removal tool 1 in more detail, The connection between the outer rod portion 10 and the inner rod portion 11 is performed between the outer rod portion 10 of the portion protruding from the void tube 2 and the inner rod portion 11 in the state where the outer rod portion 10 is inserted to the length of the void tube 2 (the state shown in Fig. 3(B)), as shown in Fig. 2(A). In the illustrated example, the connection plates 16, 16 are fixed at two locations spaced apart in the axial direction of each rod portion to connect them, but three or more connection plates 16 may be provided, or they may be connected by a continuous connection plate that extends substantially over the entire length of the parallel portions of the outer rod portion 10 and the inner rod portion 11.

[0034] The separation width between the outer rod portion 10 and the inner rod portion 11 only needs to be a width capable of sandwiching at least the thick portion of the void tube 2. However, when the inner rod portion 11 is rotated, it is preferable to form the width about 1.5 to 5 times the thickness of the void tube 2 so that each rod portion 10, 11 can move easily and the void tube 2 can be easily peeled off from the concrete 3.

[0035] The weight of the removing device 1 is preferably within 20 kg, more preferably within 15 kg, considering manual transportation to the work site. Further, the removing device 1 is made lightweight by minimizing the number of parts.

[0036] The outer rod portion 10 is a steel rod made of a solid round rod, square rod, polygonal rod, etc. having sufficient rigidity so that plastic deformation due to buckling or bending does not occur when inserted between the void tube 2 and the concrete 3 or when the inner rod portion 11 is rotated.

[0037] The diameter of the main body portion (intermediate portion) of the outer rod portion 10 is formed to be equal to or less than, preferably smaller than, the diameter of the main body portion (intermediate portion) of the inner rod portion 11. Thereby, the resistance when the outer rod portion 10 is inserted between the void tube 2 and the concrete 3 becomes small, and it becomes easy to insert the outer rod portion 10 between the void tube 2 and the concrete 3. The ratio of the diameters of the outer rod portion 10 and the inner rod portion 11 is such that the diameter of the outer rod portion 10 is 100 to 70%, preferably 90 to 80%, of the diameter of the inner rod portion 11.

[0038] At the insertion-side end of the outer rod portion 10, a pointed end portion 12 having a sharp shape with a gradually decreasing thickness on the tip side is formed to facilitate peeling of the outer peripheral surface of the void tube 2 adhered to the concrete 3 from the concrete 3. As shown in Fig. 2(A), by bending the pointed end portion 12 in a V shape toward the outside (the concrete 3 side), when the outer rod portion 10 is inserted between the void tube 2 and the concrete 3, the outer peripheral surface of the void tube 2 can be more easily peeled from the concrete 3, which is more preferable. In order to ensure that such a peeling effect can be exerted, the edge of the pointed end portion 12 is preferably bent so as to extend outside the outer peripheral surface of the rod portion of the main body portion as in the illustrated example.

[0039] The pedestal portion 13 provided at the end of the outer rod portion 10 protruding from the void tube 2 is a steel member having a central axis coaxial with the central axis of the outer rod portion 10 and consisting of a cylinder, prism, polygonal prism, etc. with a larger diameter than the outer rod portion 10. By striking the end face of the pedestal portion 13 with a hammer 20 or the like, an axial impact force can be applied from the pedestal portion 13 toward the pointed end portion 12 along the central axis of the outer rod portion 10, and when this impact force is transmitted to the pointed end portion 12 via the outer rod portion 10, the outer surface of the void tube 2 is peeled from the concrete 3 and the outer rod portion 10 can be inserted between the void tube 2 and the concrete 3. Note that the pedestal portion 13 may be arranged so as to have a central axis at a position eccentric from the central axis of the outer rod portion 10.

[0040] The inner rod portion 11 is a steel rod made of a solid round bar, square bar, polygonal bar, etc. or a hollow circular tube, square tube, etc. having sufficient rigidity so that torsional or bending plastic deformation does not occur when rotated around the central axis.

[0041] As shown in Fig. 2, the length of the inner rod portion 11 on the side arranged on the inner space side of the void tube 2 is formed to be approximately the same length as the outer rod portion 10. On the other hand, the length on the side protruding from the void tube 2 is formed longer than the outer rod portion 10 in order to facilitate rotation by attaching a handle 15 to the handle attachment portion 14 provided at the end. Further, the inner rod portion 11 is formed with substantially the same diameter over the entire length.

[0042] The handle mounting portion 14 provided at the end of the inner rod portion 11 protruding from the void tube 2 is, as shown in FIG. 2, composed of a tubular member 17 into which a rod-shaped handle 15 can be fitted and whose axial direction extends in a direction perpendicular to the central axis of the inner rod portion 11, and clamps 18, 18 to which the handle 15 fixed to both ends thereof can be fixed.

[0043] The handle 15 is not particularly limited as long as it is a straight rod-shaped member, and a solid rod material or a hollow pipe material can be used. In particular, it is preferable to use a single pipe generally used as a scaffolding material.

[0044] To fix the handle 15 to the handle mounting portion 14, with the clamps 18, 18 loosened, the handle 15 is fitted into the tubular member 17 and then tightened and fixed with at least one of the clamps 18. The handle 15 is preferably fixed to the handle mounting portion 14 with one end side extending longer than the other end side, whereby it becomes easier to rotate the inner rod portion 11 around the central axis by holding the handle 15 at the portion that extends longer.

[0045] Next, the peeling form of the void tube 2 will be described with reference to FIGS. 4 and 5. FIG. 4 is a first form example showing the peeling process of the void tube 2, and FIG. 5 is a second form example showing the peeling process of the void tube 2. In both figures, the outer rod portion 10 is indicated by a white circle (○), and the inner rod portion 11 is indicated by a black circle (●).

[0046] First, in the first exemplary embodiment, as shown in FIG. 4, (A) the outer rod portion 10 is inserted between the void tube 2 and the concrete 3, and the inner rod portion 11 is disposed on the central axis side of the void tube 2 through the wall thickness portion of the void tube 2. (B) When a rotational force is applied to the inner rod portion 11, since the outer rod portion 10 is sandwiched by the void tube 2, the inner rod portion 11 moves to a position where it abuts against the concrete 3 through the void tube 2 with the outer rod portion 10 as the center. (C) When a rotational force is further applied to the inner rod portion 11 in this state, since the reaction force of the movement of the inner rod portion 11 is supported by the concrete 3, this time the outer rod portion 10 rotates around the central axis of the inner rod portion 11, and the outer surface of the void tube 2 peels off from the concrete 3 ((D)). When the rotational force is further continuously applied to the inner rod portion 11, (E) the outer rod portion 10 abuts against the concrete 3 through the void tube 2 in which the wall thickness portion is wound up and double-layered, and (F) due to the reaction force, the inner rod portion 11 itself rotates around the outer rod portion 10, so that the outer surface of the void tube 2 peels off from the concrete 3, and then the void tube 2 peels off and is removed by winding around the outer rod portion 10 and the inner rod portion 11.

[0047] Such a peeling process occurs because a rotational force is applied only to the inner rod portion 11 among the two rod portions composed of the outer rod portion 10 and the inner rod portion 11. As a result, the void tube 2 can be easily peeled off with a smaller rotational force than when a rotational force is applied to the two rod portions simultaneously.

[0048] Next, in the second exemplary form, as shown in FIG. 5, the initial peeling form ((A) to (D)) is the same as that in the first exemplary form. However, once the void tube 2 can be peeled to a certain extent, the position where the outer rod portion 10 and the inner rod portion 11 sandwich the wall thickness portion of the void tube 2 is moved to the peeled side, and a rotational force is applied again at that position, so as to gradually expand the peeling area. By repeating such movement of the sandwiching position at several locations in the circumferential direction of the void tube 2, peeling can be performed over the entire circumference. In addition, when moving the sandwiching position, it can be easily performed simply by moving along the peeled void tube 2 without pulling out the removing device 1. This form is particularly suitable when the diameter of the void tube 2 is large and it is difficult to wind it up at one location.

Explanation of Signs

[0049] 1... Removing device, 2... Void tube, 3... Concrete, 10... Outer rod portion, 11... Inner rod portion, 12... Tip portion, 13... Base portion, 14... Handle attachment portion, 15... Handle, 16... Connecting plate, 17... Pipe member, 18... Clamp

Claims

1. A removing tool used when removing a paper void tube embedded in concrete, having a structure in which outer rod portions are arranged in parallel with a space therebetween into which the wall thickness portion of the void tube can be inserted and are inserted between the void tube and the surrounding concrete, and an inner rod portion arranged on the inner void side of the void tube are partially connected, wherein the outer rod portion is formed with a pointed tip portion having a gradually decreasing thickness at the end on the inserted side, and a pedestal portion for applying an impact force in the axial direction of the outer rod portion is provided on the other end side, and the inner rod portion is provided with a handle attachment portion to which a handle for rotating the inner rod portion around the central axis can be attached at the end on the side protruding from the void tube. The removing tool for a paper void tube is characterized by this.

2. The removing tool for a paper void tube according to claim 1, wherein the pointed tip portion is formed by being bent outward in a < shape.

3. The removing tool for a paper void tube according to claim 1, wherein the handle attachment portion is constituted by a tubular member into which the rod-shaped handle can be fitted and whose axial direction extends in a direction perpendicular to the central axis of the inner rod portion.

4. The removing tool for a paper void tube according to claim 1, wherein the length of the inner rod portion on the side protruding from the void tube is formed longer than that of the outer rod portion.

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