JPH022830Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application This invention relates to a formwork used to open a hole in concrete that is open at one or both ends.

B. Conventional technology The conventional method of making vertical holes in concrete, for example, the conventional technology of constructing post holes for guardrails on roads, is to hold paper tubes vertically and fix them to concrete formwork, and then pour fresh concrete into the concrete formwork. After installing and curing the paper tubes, the paper tubes were ripped out with a metal rod to create vertical support holes in the concrete. According to this method, it takes a lot of time to remove the hard paper tube, and the work efficiency is extremely low. This is because if the paper tube is weak, it will deform under the pressure of concrete placement, so an extremely hard paper tube is used, and it takes a lot of effort to peel it off little by little. It took more time to remove the paper tube.

If the post holes can be constructed without removing the paper tube, work efficiency will be significantly improved. However, if the paper tube is left in place and the support column is fixed, various problems may occur depending on the use, such as corrosion of the paper tube and significant reduction in support strength of the support column.

Furthermore, since the paper tube can only be used once, the cost of materials is high, and many guardrail support holes are often constructed at one time, resulting in the disadvantage that it takes time and effort to dispose of the removed paper waste.

C. Purpose of the invention This invention allows anyone to easily and quickly remove the mold from a narrow and deep hole, and also allows for extremely low material costs and extremely low overall construction costs. To provide a formwork for opening holes in concrete that can be reused many times and does not generate waste debris.

D Means for solving the problems of the prior art In this invention, the entire formwork is formed into a hollow cylindrical shape, and a part is separated by extending in the axial direction, and the formwork itself is made of concrete. Although it is not deformed by the casting pressure of The attachment/detachment tool is inserted through the attachment/detachment tool so as to be able to be freely pulled out by clamping both of the protrusions, and the separation portion is removably connected via the attachment/detachment tool.

E. Function The formwork of this invention can be removed from the form by pulling out the removal tool and bending the cut point inward after the concrete has hardened. When fixing to a concrete formwork, a detachable tool is pushed in to connect the separated parts and form the whole into a cylindrical shape.

F Preferred Embodiments Hereinafter, embodiments of this invention will be described based on the drawings.

A formwork 1 shown in FIG. 1 is a formwork for constructing a hole in concrete, such as a support for a guardrail, and is formed entirely in a cylindrical shape, with a part extending in the axial direction and being separated. The separation portions are removably connected via an attachment/detachment tool 2.

This formwork 1 is entirely made of synthetic resin such as polypropylene, vinyl chloride, polyethylene, polyurethane, EVA, acrylic, etc., and its hardness and thickness are such that it does not deform under the pouring pressure of fresh concrete, but it can be used by hand or with a stick. It is determined that it can be deformed when pressed with a material. The outer diameter is 75 to 200 mmφ, and the wall thickness is usually determined to be about 2 to 7 mm, preferably about 3 to 5 mm.

The above synthetic resin materials can be used alone or in combination, but it is best to reuse waste synthetic resins such as polyethylene and polypropylene.

The formwork 1 is formed to have a long overall length, and is used by cutting it to a required length on site.

A protruding strip 4 is provided on the inner side of the edge 3 cut off in the axial direction of the formwork.

As shown in FIG. 2, the protruding strip 4 of the formwork 1 shown in FIG. The separated parts are connected.

Therefore, the attachment/detachment tool 2 is made by bending an elastic metal plate into a U-shaped cross section, and guides the U-shaped opening edge into the groove 5 of the protrusion 4 to insert and remove it from the protrusion 4.

By the way, ideally, the formwork 1 can be removed from the hardened concrete surface by its own elasticity when the removal tool 2 is removed. To achieve this,
As shown in Fig. 3, when the attachment/detachment tool is removed, one of the separated parts bends inward due to the restorability of the formwork 1. , if the radius of curvature gradually decreases from one separated edge to the other, and when both separated edges are connected with a detachable tool, the whole becomes a perfect or almost circular shape. good.

In the formwork 1 shown in FIG. 4, a slit 6 having an L-shaped cross section is provided in a protruding strip 4 to extend vertically.
The slits 6 are open on opposing surfaces of the protrusions 4 provided on both cut edges of the formwork, and a detachable tool 2 having a U-shaped cross section is inserted into the slits 6 so as to be freely drawn. The strips 4 are connected in a latched state.

Furthermore, the formwork 1 shown in FIG. 5 is provided with grooves 5 extending vertically within the protrusions 4. The groove 5 has a wide bottom. The attachment/detachment tool 2 has thick edges on both sides, and when inserted into these grooves 5, the protrusions 4 are connected to the attachment/detachment tool 2 in a clamped state.

G. Construction status A detachable tool is inserted into the ridge to connect the formwork into a cylindrical shape, which is then temporarily secured to the concrete placement site and ready-mixed concrete is poured. To temporarily secure it, it is best to lightly wrap a wire around the outer periphery and tie the wire to the concrete formwork. After the concrete has hardened, pull out the removal tool and bend the formwork inward by hand or push a rod between the formwork and concrete to remove the form.

H. Effects of the invention The formwork of this invention has a cylindrical overall shape, a part of which is separated by extending in the axial direction, and is flexible enough to forcibly deform itself. Furthermore, the separation portions are removably connected by inserting and removing an attachment/detachment tool. For this reason, even if the opening of the post hole is narrow and is quite deep, there is no need to remove it because it breaks apart inside the post hole like traditional paper tubes do.
After pulling out the removal tool, the entire surface can be completely peeled off from the concrete surface by simply bending inward a little, making it possible for anyone to easily and quickly remove the mold.

Furthermore, it can be reused many times, and the unit price per unit is not so expensive compared to conventional paper tubes, so material costs and labor costs during construction can be greatly reduced.

Furthermore, it does not generate waste materials such as paper scraps, and has many advantages such as being convenient for post-processing.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a formwork showing an embodiment of this invention, with the attachment/detachment tool and the formwork cut to a length shorter than their actual length, and Figure 2 is a perspective view of the formwork shown in Figure 1. 3 is a plan view showing the formwork shown in FIG. 1 in a demolded state, and FIGS. 4 and 5 show connecting parts of formworks according to other embodiments. FIG. 3 is an enlarged horizontal cross-sectional view. 1... Formwork, 2... Detachment tool, 3... Edge, 4...
...Protruding stripes, 5...grooves, 6...slits.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A formwork that is temporarily fixed to a site where concrete is to be placed and is used to construct a hole in the concrete, and is formed entirely in a hollow cylindrical shape, with a portion extending in the axial direction. This vertically separated part is removably connected via an attachment/detachment tool, and furthermore, although it does not deform due to the concrete placement pressure, the curvature It has the flexibility to be deformed by forcibly bending in the direction where the radius decreases, and furthermore, the part separated in the axial direction is provided with a protrusion that protrudes inward and extends vertically. is inserted into the formwork so that it can be freely pulled out vertically by gripping both protrusions, and after the concrete has hardened, the removal tool can be pulled out from the protrusions and removed from the hardened surface of the concrete. . (2) A formwork for making holes in concrete according to claim (1) of the utility model registration, which is entirely made of polypropylene, polyethylene, vinyl chloride, or EVA. (3) The protruding strip has a groove at the base opposite to the facing surface, and the detachable tool is made of resilient metal bent to have a U-shaped cross section. A formwork for making a hole in concrete as set forth in claim (1) of the utility model registration claim, wherein the opening edge is inserted into a groove and a detachable tool clamps the protruding strip.