WO2015029338A1

WO2015029338A1 - Opening-forming tool

Info

Publication number: WO2015029338A1
Application number: PCT/JP2014/004058
Authority: WO
Inventors: 信一尾子
Original assignee: 株式会社ＢＢｅｎｇ
Priority date: 2013-08-26
Filing date: 2014-08-04
Publication date: 2015-03-05
Also published as: JP6029080B2; JPWO2015029338A1; JP2013234570A

Abstract

An opening-forming tool is provided with a hollow pipe (2) and a sheet material (3) which is wrapped around the hollow pipe (2). The hollow pipe (2) has outer peripheral ribs formed on the outer periphery thereof. The outer peripheral ribs are formed helically so as to wind around the axis of the hollow pipe (2). The lead angle of the helical outer peripheral ribs is 60º.

Description

Opening forming tool

The present invention relates to an opening forming tool for forming an opening in concrete.

Conventionally, when a circular opening is formed in a concrete building, a paper cylindrical member called a void pipe (cavity pipe) is arranged, and concrete is placed around the void pipe so that the concrete is The void tube was removed after setting.

Since conventional void tubes are made of paper, they have poor peelability from concrete and cannot be removed after the concrete has hardened. Therefore, conventionally, after the concrete has hardened, the void pipe is peeled off from the concrete while being deformed or broken. As described above, the conventional paper void tube is deformed and damaged when removed from the concrete, and thus cannot be reused. Moreover, it takes time to remove the void pipe from the concrete, and the burden on the operator is great.

Therefore, the applicant of the present application has proposed a concrete opening forming method using a sheet material as disclosed in Patent Document 1. In this opening forming method, a resin sheet material is wound around a void tube, and concrete is placed around the periphery. As described in Paragraph 0047 of FIG. 6 and FIG. 6, after the concrete is hardened, the operator pulls out the void tube from the sheet material. Thereby, since a void pipe | tube can be removed from concrete intact, the said void pipe | tube can be reused. Further, the resin sheet material can be easily peeled off from the concrete. Therefore, the sheet material can also be reused.

JP 2012-36635 A

By the way, when the void tube is pulled out as shown in FIG. 6 of Patent Document 1, a frictional resistance is generated between the void tube and the sheet material wound around the void tube. Therefore, in order to pull out the void tube, the operator needs to pull the void tube with a force that can overcome the frictional resistance. When this inventor repeated examination about this point, it turned out that the frictional resistance between the void pipe and sheet material of patent documents 1 is quite large, and in order to extract the said void pipe, big power is needed. For this reason, there is room for improvement in terms of reducing the burden on the operator who performs the work of extracting the void tube.

The present invention has been made in view of the above circumstances, and its main purpose is to form an opening in which a skin material (sheet material) is disposed around a void pipe and concrete is placed around the skin material. It is an object of the present invention to provide a configuration in which a void tube can be easily extracted from a skin material after concrete has hardened.

Means and effects for solving the problems

The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

According to the aspect of the present invention, the following opening forming tool is provided. In other words, the opening forming tool includes a hollow tube and a skin material disposed around the hollow tube. The hollow tube has a plurality of outer peripheral ribs formed in a rib shape on the outer periphery thereof.

Thus, by providing ribs on the outer periphery of the hollow tube, the contact area between the hollow tube and the outer skin material can be reduced compared to the conventional case. Thereby, the frictional resistance when pulling out the hollow tube from the outer skin material is reduced, and the hollow tube can be pulled out easily, so that the burden on the operator can be reduced.

It is preferable that the opening forming tool is configured as follows. That is, a plurality of axial ribs along the direction parallel to the axis of the hollow tube are formed on the surface of the outer skin material facing the hollow tube. The outer peripheral rib is formed in a spiral shape so as to turn around the axis of the hollow tube.

This causes the outer peripheral rib on the hollow tube side and the axial rib on the outer skin material side to contact at a “point”. Thereby, since the contact area of a cavity pipe | tube and an outer_layer | skin material becomes small, the frictional resistance between both can be made still smaller.

In the opening forming tool, the lead angle of the spiral outer peripheral rib is preferably 50 ° or more and 70 ° or less.

Thus, by setting the lead angle of the outer peripheral rib to around 60 °, the hollow tube can be smoothly extracted from the outer skin material.

In the opening forming tool described above, it is preferable that four tube core ribs protruding toward the inner side are provided at equal intervals in the circumferential direction on the inner side of the hollow tube.

The opening forming tool can be aligned using this tube core rib as a mark.

In the opening forming tool, the tube core rib and the outer peripheral rib are preferably formed continuously over the entire length in the axial direction of the hollow tube.

According to this, the hollow tube can be cut and used at an arbitrary location.

The opening forming tool of the present invention can also be configured as follows. That is, the hollow tube is composed of a plurality of substantially cylindrical connecting members that can be connected in the axial direction. The outer peripheral rib is formed on the outer periphery of each connecting member.

As described above, the length of the hollow tube can be changed by connecting the plurality of connecting members in the axial direction. Thereby, the length of a cavity pipe | tube can be adjusted according to a condition.

It is preferable that the opening forming tool is configured as follows. That is, a male screw is formed at the end of each connecting member in the axial direction. A female screw is formed at the other end of each connecting member so that the male screw of the other connecting member can be screwed therein.

A plurality of connecting members can be connected in the axial direction by providing a screw at the end of each connecting member. Further, the axial length of the hollow tube can be finely adjusted by adjusting the screwing amount of the screw.

It is preferable that the opening forming tool is configured as follows. That is, this opening part formation tool is provided with the fixing | fixed part fixed to the edge part of the axial direction of the said hollow pipe. The fixing portion includes a nail holding portion that holds a nail for fixing the opening forming tool in a predetermined position.

This facilitates the work of fixing the opening forming tool with the nail.

In the above-described opening forming tool, it is preferable that four tube core protrusions protruding toward the inner side are provided at equal intervals in the circumferential direction inside the fixed portion.

The opening forming tool can be aligned using this tube core protrusion as a mark.

It is preferable that the opening forming tool includes a lid portion that closes an end portion in the axial direction of the hollow tube.

設ける By providing the lid in this way, it is possible to prevent the concrete from flowing into the connecting member.

In the opening forming tool, the lid is preferably provided with a seal member that can contact an end surface of the outer skin material.

This can prevent the inflow of concrete or the like between the outer skin material and the connecting member.

The opening forming tool preferably includes a handle portion that is gripped when the hollow tube is extracted from the outer skin material.

Thereby, after the concrete is hardened, the hollow tube can be easily extracted through the handle portion.

In the opening forming tool, the handle is preferably formed integrally with the hollow tube or fixed to the hollow tube with a removable structure.

Thereby, it is possible to realize an opening forming tool that can easily pull out the hollow tube by pulling the handle portion with a simple configuration.

In the opening forming tool, it is preferable that a through-hole penetrating the inner peripheral side and the outer peripheral side of the hollow pipe is formed between the outer peripheral ribs.

Thus, if a through-hole is formed in the hollow tube, the operator can devise himself / herself to make it easier to work, such as creating a handle by passing a string or wire through the through-hole. And since the through-hole was formed between the outer periphery ribs, the said through-hole does not get caught in a shell material, and a cavity pipe | tube can be extracted smoothly.

According to another aspect of the present invention, there is provided the following configuration of a hollow tube used when forming an opening in concrete. That is, this hollow tube has a plurality of outer peripheral ribs formed in a rib shape on the outer periphery thereof. The outer peripheral rib is formed in a spiral shape so as to turn around the axis of the hollow tube. The lead angle of the spiral outer peripheral rib is not less than 50 ° and not more than 70 °.

The perspective view of the opening part formation tool which concerns on 1st Embodiment of this invention. The perspective view of a sheet | seat material. The perspective view of the cavity pipe | tube of 1st Embodiment. The side view of the cavity pipe | tube of 1st Embodiment. (A) Plan sectional drawing of the cavity pipe | tube of 1st Embodiment. (B) Side surface sectional drawing of the cavity pipe | tube of 1st Embodiment. The perspective view which shows a mode that a sheet | seat material is wound around a cavity pipe | tube. The perspective view which shows a mode that an opening part formation tool is installed. The perspective view which shows a mode that concrete was laid around the opening part formation tool. The perspective view which shows a mode that a hollow pipe is extracted from a sheet | seat material. The figure of the opening part formation tool which concerns on 2nd Embodiment. The exploded view of the opening part formation tool of 2nd Embodiment. The top view of a fixing | fixed part. The figure which shows the modification of 1st Embodiment. The figure which shows the modification of 2nd Embodiment. The perspective view which shows a mode that concrete was laid around the opening part formation tool which has a handle part in the 2nd modification of 1st Embodiment. The perspective view which shows a mode that the hollow pipe which has a handle part is pulled out from a sheet | seat material. The figure which shows the other example of a handle part.

Next, a first embodiment of the present invention will be described with reference to the drawings. The opening forming tool 1 of this embodiment shown in FIG. 1 is used in place of a paper-made void tube that has been conventionally used when forming a circular opening in concrete. The opening forming tool 1 of the present embodiment includes a substantially cylindrical hollow tube (void tube) 2 and a sheet material (outer material) 3 wound around the hollow tube 2.

First, the sheet material (skin material) 3 will be described. As shown in FIG. 2, the sheet material 3 is formed in a sheet shape. The sheet material 3 is formed into a substantially cylindrical shape by curving (rounding), butting both ends together and fixing with an adhesive tape 9 (state of FIG. 1). The material of the sheet material 3 is not particularly limited, but it is preferable to use a synthetic resin because it is easy to peel from concrete and can realize appropriate flexibility. Note that the sheet material 3 of the present embodiment is made of polyethylene.

As shown in FIG. 2, the sheet material 3 is formed in a so-called single-sided cardboard shape. That is, the sheet material 3 has a flat surface on one side and a plurality of axial ribs 5 on the other side. The axial rib 5 is formed elongated along one direction. The plurality of axial ribs 5 are formed in parallel at equal intervals.

Since the sheet material 3 is formed in a single-sided cardboard shape in this way, the sheet material 3 is curved in a plane orthogonal to the longitudinal direction of the axial rib 5 and the periphery of the hollow tube 2 as shown in FIG. Can be wrapped around. In the state in which the sheet material 3 is wound around the cavity tube 2 (the sheet material 3 is configured in a cylindrical shape, FIG. 1), the longitudinal direction of each axial rib 5 is the axis 6 (center of the cavity tube 2). Axis). Accordingly, it can be said that each axial rib 5 is formed along a direction in which the longitudinal direction is parallel to the axis 6 of the hollow tube.

As shown in FIG. 6, the sheet material 3 is wound around the cavity tube 2 with the surface on which the axial rib 5 is formed facing the cavity tube 2 side (that is, the shaft of the sheet material 3). The direction rib 5 is located on the inner peripheral side when the sheet material 3 is rolled into a cylindrical shape).

Subsequently, the hollow tube 2 will be described. The material of the hollow tube 2 is not particularly limited, but the hollow tube 2 of the present embodiment is made of polypropylene (PP). Since polypropylene is excellent in rigidity and water resistance, it is suitable as a material for the hollow tube 2.

As shown in FIGS. 3 and 4, the hollow tube 2 is substantially cylindrical, and a plurality of outer peripheral ribs 7 are formed on the outer periphery thereof.

As shown in FIG. 5, each outer peripheral rib 7 is formed to be convex outward in the radial direction of the cavity tube 2. As shown in the cross-sectional view of FIG. 5A, each outer peripheral rib 7 has a rounded cross-sectional shape (no sharp part) when cut along a plane perpendicular to the axis 6 of the hollow tube 2. Shape). Thereby, the sheet material 3 can be prevented from being damaged by the outer peripheral rib 7.

As shown in FIG. 3, each outer peripheral rib 7 is formed along a spiral (string winding) whose longitudinal direction turns around the axis 6 of the hollow tube 2. That is, each outer peripheral rib 7 is formed in a spiral shape (string winding shape). Thereby, the hollow pipe 2 has a screw-like or drill-like appearance. As shown in FIG. 4, in this embodiment, the lead angle when each outer peripheral rib 7 is viewed as a screw thread is about 60 °.

As shown in FIG. 5, four tube core ribs 8 are formed on the inner peripheral surface of the hollow tube 2 so as to protrude inward in the radial direction. As shown in FIG. 5 (b), each tube core rib 8 is formed so that its longitudinal direction is parallel to the axis 6 of the hollow tube 2. Further, as shown in FIG. 5A, the four core ribs 8 are arranged at equal intervals in the circumferential direction (that is, at intervals of 90 °).

3 and 4, each outer peripheral rib 7 is continuously formed over the entire length of the hollow tube 2 in the axial direction. Further, as shown in FIG. 5B, each tube core rib 8 is continuously formed over the entire axial length of the hollow tube 2. Therefore, even if the cavity tube 2 is cut at any position in the axial direction, a cut surface having substantially the same shape can be obtained. Thereby, it is possible to cut and use the hollow tube 2 with an arbitrary length.

Note that, as shown in FIG. 5B, a nail holding member 24 can be attached to the end of the hollow tube 2. The nail holding member 24 is configured to be able to hold a nail 23 for fixing the cavity tube 2 and is also used in a conventional void tube. The nail holding member 24 is configured in a clip shape, and can be easily attached to the end of the cavity tube 2 so as to sandwich the edge of the cavity tube 2. With the nail 23 held by the nail holding member 24 (the state shown in FIG. 5B), the cavity tube 2 is placed on the installation surface, and the nail 23 is driven against the installation surface to install the cavity tube 2 Secure to the surface.

Subsequently, features of the opening forming tool 1 of the present embodiment will be described.

As described above, the sheet material 3 is formed with the axial rib 5 on the surface facing the cavity tube 2 side. On the other hand, an outer peripheral rib 7 is formed around the cavity tube 2. Accordingly, in a state where the sheet material 3 is wound around the cavity tube 2 (FIG. 1), the outer peripheral rib 7 on the cavity tube 2 side and the axial rib 5 on the sheet material 3 side are in contact with each other.

Thus, the hollow tube 2 of the present embodiment comes into contact with the sheet material 3 by the outer peripheral rib 7 formed around the periphery. Therefore, the cavity tube 2 of the present embodiment can reduce the contact area with the sheet material 3 as compared with the cavity tube of Patent Document 1 in which no ribs are formed in the periphery (a cavity tube without irregularities in the periphery). it can.

Here, suppose that the outer peripheral rib 7 of the hollow tube 2 is formed parallel to the axis 6 (the outer peripheral rib 7 is not spiral). In this case, the longitudinal direction of the outer peripheral rib 7 and the longitudinal direction of the axial rib 5 are parallel. Then, it is considered that the axial rib 5 enters between the outer peripheral ribs 7 and the ribs are engaged with each other. In this case, the contact area between the hollow tube 2 and the sheet material 3 may increase.

In this regard, as described above, the outer peripheral rib 7 of the present embodiment is formed in a spiral shape that rotates around the axis 6 of the hollow tube 2. Thereby, since the longitudinal direction of the outer peripheral rib 7 and the longitudinal direction of the axial rib 5 are not parallel, the axial rib 5 does not enter between the outer peripheral ribs 7. In addition, since the longitudinal direction of the outer peripheral rib 7 and the longitudinal direction of the axial rib 5 are in a positional relationship so as to intersect each other, the outer peripheral rib 7 and the axial rib 5 come into contact with each other at “points”. Thereby, the contact area of the hollow tube 2 and the sheet material 3 can be further reduced.

Then, the usage method of the opening part formation tool 1 of this embodiment is demonstrated.

First, the operator prepares the hollow tube 2 having a diameter corresponding to the diameter of the opening to be formed in the concrete. The operator cuts the hollow tube 2 as necessary, and adjusts the axial length of the hollow tube 2.

Next, the operator prepares a sheet material 3 to be wound around the hollow tube 2. The sheet material 3 may be prepared in advance according to the size of the hollow tube 2, but the operator may form the sheet material 3 having a size necessary for the site. For example, a sheet material formed with a large vertical width and horizontal width is prepared, and an operator cuts out and uses the necessary size. Since the sheet material 3 of this embodiment is made of polyethylene, it can be easily cut using scissors, a cutter knife, or the like, and the sheet material 3 having a required size can be formed on the spot.

Then, the operator winds the sheet material 3 around the hollow tube 2 (FIG. 6). An operator can fix the sheet material 3 as appropriate using an adhesive tape 9 (FIG. 1) or the like so that the sheet material 3 wound around the hollow tube 2 does not come off. Thereby, the opening part formation tool 1 of this embodiment shown in FIG. 1 is comprised.

Before and after this, the operator attaches the above-described nail holding member 24 to the end portion of the hollow tube 2 (see FIG. 5B) and holds the nail 23 on the nail holding member 24.

The worker arranges the opening forming tool 1 configured as described above at a predetermined position on the installation surface 98 as shown in FIG. A reference line 10 is drawn on the installation surface 98 on which the opening forming tool 1 is to be placed by an appropriate method such as inking (FIG. 7). The operator aligns the opening forming tool 1 at a predetermined position on the installation surface 98 with the reference line 10 as a reference. At this time, the operator can use the tube core rib 8 formed on the inner periphery of the hollow tube 2 as a mark for alignment.

That is, the operator can determine the position of the axis 6 (tube core) of the hollow tube 2 using the four tube core ribs 8 formed on the inner periphery of the hollow tube 2 as a mark (FIG. 5 ( a)). Therefore, the position of the axis 6 of the hollow tube 2 can be aligned with the reference line 10 described above. Thereby, the opening part formation tool 1 can be correctly arrange | positioned in the predetermined position of the installation surface 98. FIG. In this state, the operator fixes the opening forming tool 1 at a predetermined position on the installation surface 98 by driving the nail 23 against the installation surface 98.

Then, the worker places concrete 99 around the arranged opening forming tool 1 (FIG. 8).

When the concrete 99 is hardened, the operator pulls out the hollow tube 2 from the sheet material 3 (FIG. 9). As described above, in the opening forming tool 1 of the present embodiment, since the spiral outer peripheral rib 7 is formed around the cavity tube 2, the contact area between the cavity tube 2 and the sheet material 3 is as follows. It is smaller than the conventional one (Patent Document 1). Therefore, the frictional resistance when pulling out the hollow tube 2 from the sheet material 3 is smaller than the conventional one. Thereby, the operator can pull out the hollow pipe 2 easily. Thus, after the concrete 99 is hardened, the hollow tube 2 of this embodiment can be pulled out without being damaged, so that the hollow tube 2 can be reused.

By the way, since the outer peripheral rib 7 of the present embodiment is formed in a spiral shape, when pulling out the hollow tube 2 from the sheet material 3, a force is applied to rotate the hollow tube 2 around the axis 6. When the force for rotating the hollow tube 2 is large, the hollow tube 2 cannot be pulled out smoothly. In this regard, as described above, in the present embodiment, the lead angle of the outer peripheral rib 7 is set to 60 °. As described above, since the lead angle of the outer peripheral rib 7 is relatively large, when the cavity tube 2 is pulled out, the force for rotating the cavity tube 2 around the axis 6 is reduced. The tube 2 can be pulled out smoothly.

It is preferable to increase the lead angle of the outer peripheral rib 7 as much as possible in terms of reducing the force for rotating the hollow tube 2. However, if the lead angle is increased too much, the outer peripheral rib 7 and the axial rib 5 are separated. Nearly parallel, the contact area between the two increases, and the frictional resistance when the hollow tube 2 is pulled out increases. Therefore, the lead angle of the outer peripheral rib 7 is particularly preferably about 60 ° as in the present embodiment.

Now, after pulling out the hollow tube 2 as described above, the operator removes the sheet material 3 (FIG. 9) remaining on the concrete 99. Since the sheet material 3 is made of synthetic resin, it can be easily peeled off from the concrete 99. Thus, since the sheet material 3 can be removed intact from the hardened concrete 99, the sheet material 3 can be reused.

In addition, the sheet | seat material 3 is wound around the cavity pipe | tube 2 with the surface (surface in which the axial direction rib 5 is not formed) of the side currently formed in planar shape facing outward (FIG. 1). ). Therefore, when the concrete 99 is placed (FIG. 8), the sheet material 3 comes into contact with the concrete 99 on the surface on which the axial ribs 5 are not formed (surface with few irregularities). Thus, since the sheet | seat material 3 contacts the concrete 99 in the surface with few unevenness | corrugations, it can peel easily from the concrete 99 after hardening.

As described above, by removing the opening forming tool 1 (the hollow tube 2 and the sheet material 3) from the hardened concrete 99, a circular opening can be formed in the concrete 99.

As described above, the opening forming tool 1 of the present embodiment includes the hollow tube 2 and the sheet material 3 wound around the hollow tube 2. The hollow tube 2 has a plurality of outer peripheral ribs 7 formed in a rib shape on the outer periphery thereof. The outer peripheral rib 7 is formed in a spiral shape so as to turn around the axis of the hollow tube 2. The lead angle of the spiral outer peripheral rib 7 is 60 °.

Thus, by providing the outer peripheral rib 7 on the outer periphery of the hollow tube 2, the contact area between the hollow tube 2 and the sheet material 3 can be reduced as compared with the conventional case. Thereby, the frictional resistance at the time of pulling out the hollow tube 2 from the sheet material 3 is reduced, and the hollow tube 2 can be pulled out easily, so that the burden on the operator can be reduced. In addition, since the outer peripheral rib 7 is formed in a spiral shape, the outer peripheral rib 7 on the cavity tube 2 side and the axial rib 5 on the sheet material 3 side come into contact with each other at “points”. Thereby, since the contact area of the cavity pipe | tube 2 and the sheet | seat material 3 becomes small, the frictional resistance between both can be made still smaller. Since the lead angle of the outer peripheral rib 7 is 60 °, the hollow tube 2 can be smoothly extracted from the sheet material 3.

Also, in the opening forming tool 1 of the present embodiment, four core ribs 8 that protrude toward the inside are provided at equal intervals in the circumferential direction inside the hollow tube 2. Using this tube core rib 8 as a mark, the opening forming tool 1 can be aligned.

Further, in the opening forming tool 1 of the present embodiment, the outer peripheral rib 7 and the tube core rib 8 are continuously formed over the entire axial length of the hollow tube 2. According to this, the cavity pipe | tube 2 can be cut | disconnected and utilized in arbitrary places.

Subsequently, a second embodiment of the present invention will be described. In the following description, the same or similar configurations as those of the first embodiment may be denoted by the same reference numerals as those of the first embodiment in the drawings and element names, and description thereof may be omitted.

The opening forming tool 11 of the second embodiment shown in FIG. 10 includes a hollow tube 12 and a sheet material 3 as in the first embodiment. In FIG. 10, the cross section of the sheet material 3 wound around the cavity tube 12 is indicated by a two-dot chain line.

As shown in FIG. 10, the hollow tube 12 of the present embodiment is composed of two connecting members 14. Each connecting member 14 is configured in a substantially cylindrical shape.

Each connecting member 14 is configured to be connectable in the axial direction. Specifically, as shown in FIG. 11, each connecting member 14 has a male screw 15 formed at one end in the axial direction. Further, a female screw 16 is formed at the other axial end of each connecting member 14 so that a male screw 15 of another connecting member 14 can be screwed therein. With this configuration, the two connecting members 14 can be connected in the axial direction by screwing the male screw 15 formed on one connecting member 14 into the female screw 16 formed on the other connecting member 14.

Although only two connecting members 14 are shown in FIGS. 10 and 11, according to the above configuration, any number of two or more connecting members 14 can be connected in the axial direction. Thus, by changing the number of connecting members 14 to be connected, the axial length of the hollow tube 12 can be changed as necessary. Moreover, as shown in FIG.10 and FIG.11, each connection member 14 may mutually differ in the length of an axial direction. If a plurality of types of connecting members 14 having different axial lengths are prepared in advance, the axial length of the hollow tube 12 can be changed more flexibly by selecting the type of connecting member 14 to be connected. .

Further, in the state where the plurality of connecting members 14 are connected, the axial length of the hollow tube 12 can be finely adjusted by adjusting the screwing amount of the male screw 15 into the female screw 16.

As described above, in the opening forming tool 11 of the second embodiment, the cavity tube 12 can freely change the axial length. In the above-described first embodiment, since the axial length is changed by cutting the hollow tube 2, the hollow tube 2 can be shortened in the axial direction, but it can be lengthened. It was impossible. In this regard, in the opening forming tool 11 of the second embodiment, the cavity tube 12 can be lengthened or shortened in the axial direction, and therefore, compared with the configuration of the opening forming tool 1 of the first embodiment. Thus, the reusability of the hollow tube 12 can be enhanced.

As shown in FIGS. 10 and 11, a plurality of spiral outer peripheral ribs 7 are formed on the outer periphery of each connecting member 14. Thus, the cavity tube 12 of the second embodiment is equivalent to the cavity tube 2 of the first embodiment in that the outer peripheral rib 7 is formed on the outer periphery thereof. Therefore, the hollow tube 12 of the second embodiment can also exhibit the same effect as that of the first embodiment that can be easily pulled out from the sheet material 3.

Furthermore, the opening forming tool 11 of the second embodiment includes a lid portion 17 and a fixing portion 19.

First, the lid 17 will be described. The lid portion 17 has a top plate 18 for closing the end portion of the cavity tube 12. Further, as shown in FIG. 11, a male screw 15 is provided on the surface of the top plate 18 facing the cavity tube 12 side. The male screw 15 is configured to be screwed into the female screw 16 of the connecting member 14. That is, by screwing the male screw of the lid portion 17 into the female screw of the connecting member 14, the lid portion 17 can be attached to the end portion in the axial direction of the hollow tube 12 as shown in FIG. 10. Thereby, since the edge part of the axial direction of the cavity pipe | tube 12 will be in the state (FIG. 10) obstruct | occluded with the top plate 18, it can prevent that concrete flows in into the said cavity pipe | tube 12. FIG.

Further, as shown in FIG. 10, a sealing member 20 that can contact the end surface of the sheet material 3 is disposed on the top plate 18 of the lid portion 17. In the present embodiment, the seal member 20 is a rubber packing. The radial width of the sealing member 20 is configured to be the same as or slightly thicker than the thickness of the sheet material 3 (the thickness including the axial rib 5). Thereby, the said sealing member 20 can be made to contact with respect to the full width of the end surface of the sheet | seat material 3. FIG. Since the seal member 20 contacts the end face of the sheet material 3 (the state shown in FIG. 10), the gap between the sheet material 3 and the lid portion 17 can be sealed, so that the concrete flows between the sheet material 3 and the hollow tube 12. Can be prevented.

Next, the fixing unit 19 will be described. As shown in FIG. 10, the fixing portion 19 is fixed to an end portion opposite to the lid portion 17 in the axial direction of the hollow tube 12. As shown in FIG. 11, a female screw 16 is formed in the fixing portion 19. The female screw 16 is configured so that the male screw of the connecting member 14 can be screwed therein. That is, by screwing the male screw 15 of the connecting member 14 into the female screw 16 of the fixing portion 19, the fixing portion 19 can be attached to the axial end portion of the cavity tube 12 as shown in FIG. 10. .

As shown in FIG. 12, the fixing portion 19 is formed in a substantially annular shape (ring shape) in plan view. A nail holding portion 21 is formed on the inner peripheral side of the fixing portion 19. The nail holding part 21 is formed integrally with the fixing part 19. As shown in FIG. 11, the nail holding part 21 is configured to hold a nail 23 for fixing the opening forming tool 11 at a predetermined position. In the present embodiment, the three nail holding portions 21 are arranged at equal intervals (that is, at 120 ° intervals) in the circumferential direction of the ring-shaped fixing portion 19.

In the first embodiment described above, since the nail 23 is held by the clip-like nail holding member 24 attached to the edge of the cavity tube 2, the nail holding member 24 comes off the cavity tube 2. was there. In this regard, in the opening forming tool 11 of the second embodiment, since the nail holding part 21 is integrally formed with the fixing part 19, there is no possibility that the nail holding part 21 comes off the cavity pipe 12.

The fixing part 19 of the present embodiment has a reinforcing part 25. As shown in FIG. 12, in this embodiment, the three reinforcement parts 25 are provided radially. Each reinforcing portion 25 is formed in a rod shape or a beam shape, and one end portion thereof is connected to the nail holding portion 21. The other end portions of the reinforcing portions 25 are connected to each other at the axial center portion of the fixing portion 19. The reinforcing part 25 is formed integrally with the fixing part 19 and the nail holding part 21. Thus, the reinforcing portion 25 has a function as a beam connecting the nail holding portions 21. With the above configuration, the strength of each nail holding portion 21 is increased, and deformation, breakage, and the like of the nail holding portion 21 can be prevented.

Further, as shown in FIGS. 11 and 12, the fixed portion 19 is formed with four tube core protrusions 22 protruding inward in the radial direction at equal intervals in the circumferential direction. Similar to the tube core rib 8 of the first embodiment, the tube core protrusion 22 is used by the operator as a mark when aligning the opening forming tool 11. In the present embodiment, the uppermost nail holding portion 21 in FIG. 12 (the nail holding portion at the 12 o'clock position in FIG. 12) also serves as the tube core protrusion 22. As described above, the tube core protrusion 22 may also serve as the nail holding portion 21.

The outer peripheral rib is not formed in the fixing part 19 of this embodiment. As shown in FIG. 10, the fixing portion 19 has an outer diameter slightly smaller than the outer diameter of the connecting member 14 (the outer diameter including the outer peripheral rib 7). Thereby, since the fixing | fixed part 19 does not contact the sheet | seat material 3, when pulling out the cavity pipe | tube 12 from the sheet | seat material 3, it can prevent that the fixing | fixed part 19 gets caught in a sheet | seat material.

As described above, in the opening forming tool 11 of the second embodiment, the hollow tube 12 is composed of a plurality of substantially cylindrical connecting members 14 that can be connected in the axial direction. An outer peripheral rib 7 is formed on the outer periphery of each connecting member 14. A male screw 15 is formed at the end of each connecting member 14 in the axial direction. A female screw 16 is formed at the other end of each connecting member 14 so that the male screw 15 of the other connecting member 14 can be screwed therein.

Thus, the length of the hollow tube 12 can be changed by connecting the plurality of connecting members 14 in the axial direction. Thereby, the length of a cavity pipe | tube can be adjusted according to a condition. Further, the axial length of the hollow tube 12 can be finely adjusted by adjusting the screwing amount of the screw.

Further, the opening forming tool 11 of the second embodiment includes a fixing portion 19 that is fixed to an end portion of the hollow tube 12 in the axial direction. The fixing portion 19 has a nail holding portion 21 that holds a nail 23 for fixing the opening forming tool 11 at a predetermined position. This facilitates the work of fixing the opening forming tool 11 with the nail 23.

Further, in the opening forming tool 11 of the second embodiment, on the inner side of the fixed portion 19, four core protrusions 22 that are convex inward are provided at equal intervals in the circumferential direction. The opening forming tool 11 can be aligned using the tube core protrusion 22 as a mark.

Further, the opening forming tool 11 of the second embodiment includes a lid portion 17 that closes an end portion of the hollow tube 12 in the axial direction. The lid portion 17 is provided with a seal member 20 that can contact the end surface of the sheet material 3. By providing the lid portion in this way, it is possible to prevent the concrete from flowing into the inside of the connecting member 14 or between the sheet material 3 and the connecting member 14.

Next, a modification of the above embodiment will be described.

FIG. 13 shows a modification of the first embodiment, and FIG. 14 shows a modification of the second embodiment. In this modification, a plurality of through-holes 30 are formed in the hollow tube so as to communicate the inner peripheral side and the outer peripheral side thereof. In the modification shown in FIGS. 13 and 14, the through holes 30 are formed at equal intervals in the circumferential direction and the axial direction of the hollow tube. However, the number of through holes 30 to be formed and the arrangement of the through holes 30 can be changed as appropriate.

The method of using this through hole 30 is not particularly limited, and can be used by the operator himself. For example, an operator can form a “handle” through a wire (wire) or a string through a through hole 30 formed in the hollow tube. This “handle” facilitates the work of pulling out the hollow tube from the sheet material 3.

Each through hole 30 is formed in a valley portion between the outer peripheral ribs 7. That is, the through hole 30 is not formed in a portion where the hollow tube and the sheet material 3 are in contact with each other. Accordingly, the edge of the through hole 30 is not caught on the sheet material 3 when the hollow tube is pulled out from the sheet material 3.

Next, a second modification of the first embodiment will be described with reference to FIGS.

In the second modification of the first embodiment shown in FIGS. 15 and 16, the opening forming tool 1 includes a handle portion 26 that can be gripped when an operator pulls out the hollow tube 2. The handle portion 26 is formed integrally with the cavity tube 2 so that the force pulling the handle portion 26 can be transmitted to the cavity tube 2. Specifically, the lid portion 17x is integrally formed so as to close one end of the hollow tube 2, and the handle portion 26 is integrally formed so as to be connected to the edge portion of the lid portion 17x.

However, not limited to this configuration, for example, the lid portion 17x may be omitted, and the handle portion 26 may be directly formed integrally with the hollow tube 2. Moreover, the handle part 26 can also be attached to the hollow tube 2 or the lid part 17x by a detachable fixing tool (screw or the like). Further, in the second embodiment shown in FIG. 10, the handle portion 26 is attached to the lid portion 17 (in other words, the lid portion 17 configured to be detachably fixed to the cavity tube 12) attached to the hollow tube 12 by male screws and female screws. The connecting member 14 can be provided with a handle 26.

The handle portion 26 is disposed at an end portion on one side of the hollow tube 2 in the axial direction. As shown in FIG. 15, the handle portion 26 is exposed to the outside of the concrete 99 in a state where the concrete 99 is placed around the arranged opening forming tool 1. Accordingly, as shown in FIG. 16, the hollow tube 2 can be easily pulled out from the sheet material 3 through the handle portion 26. The handle portion 26 is not limited to the shape shown in FIGS. 15 and 16, and is parallel to the hollow tube 2 as shown in FIG. 17A depending on the diameter or application of the opening to be formed. You may form in a rod shape, or you may form so that it may have a long neck part and ring part as shown in FIG.17 (b).

As described above, the opening forming tool 1 of the present modification includes a handle portion 26 that is gripped when the hollow tube 2 is extracted from the sheet material 3.

Thereby, after the concrete is hardened, the hollow tube 12 can be easily extracted through the handle portion 26.

Further, in the opening forming tool 1 of the present modification, the handle portion 26 is formed integrally with the cavity tube 2 or is fixed to the cavity tube 2 with a removable structure.

Thereby, it is possible to realize the opening forming tool 1 with which the hollow tube 2 can be easily extracted by pulling the handle portion 26 with a simple configuration.

Although preferred embodiments and modifications of the present invention have been described above, this configuration can be changed as appropriate.

For example, the materials of the hollow tube 2 and the sheet material 3 are not limited to the materials described in the above description, and can be changed as appropriate.

In the above embodiment, the lead angle of the outer peripheral rib 7 is 60 °, but it is not necessarily strictly 60 ° and can be changed as appropriate. However, from the viewpoint of smoothly pulling out the hollow tube from the sheet material 3, the lead angle of the outer peripheral rib 7 is around 60 ° (more specifically, 50 ° or more and 70 ° or less as in the above embodiment). Range).

In the second embodiment, either or both of the lid portion 17 and the fixing portion 19 may be omitted. In the above embodiment, a plurality of connecting members 14 are used. However, only one connecting member 14 can be used. In this case, both the lid portion 17 and the fixing portion 19 can be attached to one connecting member 14.

In the above-described embodiment, the sheet material 3 wound around the hollow tube is used as the “skin material”, but instead, the skin material may be formed in a cylindrical shape in advance.

DESCRIPTION OF SYMBOLS 1 Opening part tool 2 Cavity pipe 3 Sheet material (skin material)
5 Axial ribs 7 Outer peripheral ribs 8 Core ribs

Claims

A hollow tube,
A skin material disposed around the hollow tube;
An opening forming tool comprising:
The hollow tube has a plurality of outer peripheral ribs formed in a rib shape on the outer periphery thereof.
The opening forming tool according to claim 1,
A plurality of axial ribs along the direction parallel to the axis of the hollow tube are formed on the surface of the outer skin material facing the hollow tube,
The outer peripheral rib is formed in a spiral shape so as to turn around the axis of the hollow tube.
The opening forming tool according to claim 2,
The opening forming tool, wherein a lead angle of the spiral outer peripheral rib is not less than 50 ° and not more than 70 °.
An opening forming tool according to any one of claims 1 to 3,
An opening forming tool characterized in that four hollow core ribs are provided on the inner side of the hollow tube at equal intervals in the circumferential direction.
The opening forming tool according to claim 4,
The tube core rib and the outer peripheral rib are formed continuously over the entire axial length of the hollow tube.
An opening forming tool according to any one of claims 1 to 3,
The hollow tube is composed of a plurality of substantially cylindrical connecting members connectable in the axial direction,
An opening forming tool, wherein the outer peripheral rib is formed on the outer periphery of each connecting member.
The opening forming tool according to claim 6,
A male screw is formed at the axial end of each connecting member,
An opening forming tool, wherein a female screw is formed at the other end of each connecting member so that the male screw of the other connecting member can be screwed therein.
The opening forming tool according to claim 6 or 7,
A fixing portion fixed to an end of the hollow tube,
The said fixing | fixed part has a nail holding | maintenance part holding the nail for fixing the said opening part formation tool in a predetermined position, The opening part formation tool characterized by the above-mentioned.
The opening forming tool according to claim 8,
An opening forming tool characterized in that four tube core protrusions that protrude inward are provided at equal intervals in the circumferential direction on the inner side of the fixing portion.
The opening forming tool according to any one of claims 6 to 9,
An opening forming tool comprising a lid portion that closes an axial end portion of the hollow tube.
It is an opening part formation tool according to claim 10,
An opening forming tool, wherein the lid is provided with a seal member capable of contacting an end surface of the outer skin material.
An opening forming tool according to any one of claims 1 to 11,
An opening forming tool comprising a handle portion that is gripped when the hollow tube is extracted from the outer skin material.
The opening forming tool according to any one of claims 12 to 12,
The said handle part is integrally formed with the said cavity pipe | tube, or is fixed to the said cavity pipe | tube with the structure which can be removed, The opening part formation tool characterized by the above-mentioned.
It is an opening part formation tool as described in any one of Claim 1-13,
An opening forming tool characterized in that a through-hole penetrating the inner peripheral side and the outer peripheral side of the hollow pipe is formed between the outer peripheral ribs.
A hollow tube used in forming an opening in concrete,
It has a plurality of outer peripheral ribs formed in a rib shape on the outer periphery,
The outer peripheral rib is formed in a spiral shape so as to turn around the axis of the hollow pipe,
A hollow tube, wherein a lead angle of the spiral outer peripheral rib is 50 ° or more and 70 ° or less.