JP3808043B2 - Form material for forming through holes - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a formwork material for forming a through hole in a foundation beam, wall body, slab or the like of a concrete structure.
[0002]
[Prior art]
Cylindrical through holes are formed in the foundation beams, walls, slabs, and the like of the concrete structure so that various pipes can be inserted therethrough. Conventionally, a cardboard void tube and a sleeve made of hard polyvinyl chloride have been widely used as a formwork material for forming such a through hole. These formwork materials are usually removed from the through holes after curing the concrete. However, since the casting pressure of concrete is applied to the mold material, the mold material and the concrete are in close contact, so in order to remove the mold material, it can be peeled off with a tool such as a chisel or bar, In the case of a paper tube, it took a lot of work, such as wetting it with water and softening it, and then peeling it off by hand. In addition, since the mold material removed as described above becomes disposable and needs to be treated as industrial waste, there is a large waste in terms of cost, and there is a problem in terms of effective use of resources.
[0003]
Then, what was described, for example in patent documents 1-3 is proposed as a formwork material which makes easy demolding from the cast concrete. These mold materials are formed by cutting a cylindrical body made of an elastically deformable flexible material in the axial direction and superimposing the incised edges, thereby pulling the incised edge inward during demolding. The cylindrical body can be reduced in diameter.
[0004]
[Patent Document 1]
Japanese Utility Model Publication No. 1-1131754 [Patent Document 2]
JP-A-9-228636 [Patent Document 3]
Japanese Patent Laid-Open No. 2001-107560
[Problems to be solved by the invention]
According to the formwork materials described in Patent Documents 1 to 3, the diameter at the time of demolding can be reduced by cutting the cylindrical body constituting the formwork body in the axial direction. However, when the diameter of the through hole is small or the cylinder length is large compared to the diameter, manual work inside the cylinder becomes inconvenient, so it is easy to reduce the diameter of the cylinder evenly over the entire length. Not. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a form material for forming a through hole that improves the technique as described above and further facilitates the diameter reduction at the time of demolding.
[0006]
[Means for Solving the Problems]
The form material for forming a through hole of the present invention cuts a cylindrical body made of an elastically deformable flexible material in the axial direction, superposes the cut edge with an appropriate width and holds it in a cylindrical shape, A cylindrical body diameter reducing means is provided inside the cylindrical body.
[0007]
The diameter-reducing means (first diameter-reducing means) according to the first aspect includes two diameter-reducing levers arranged in the axial direction of the cylinder and two in the vicinity of both ends of the diameter-reducing lever. Link arms, and the tip of each link arm is pivotally attached to the inner surface of the cylindrical body facing the overlapped portion of the incision edge portion, and the diameter reduction lever is operated in the axial direction to operate the link arm. It is characterized in that the distance between the tips is reduced.
[0008]
That is, this diameter reducing means utilizes a six-joint parallel crank mechanism having two hinged points of the reduced diameter lever and the link arm and four pivoted points of each link arm and the inner surface of the cylinder. It is a thing. When the diameter-reducing lever located at the center is moved in the axial direction, the swing angle of the link arm with respect to the diameter-reducing lever is reduced, and the distance between the tips of the link arms is reduced. By using this mechanism, simply pulling or pushing the diameter-reducing lever from the vicinity of one open end of the cylinder, the overlapping portion of the incision edge is pulled inward to reduce the diameter of the cylinder. Can be removed from the mold.
[0009]
Further, the diameter reducing means (second diameter reducing means) according to claim 2 includes at least two or more shape memory springs arranged in a direction orthogonal to the axis of the cylinder, Both ends are respectively connected to the inner surfaces of the cylinders facing each other across the overlapping portion of the incision edge, and the distance between both ends of the shape memory spring is reduced during heating.
[0010]
This diameter-reducing means is for reducing the diameter of the cylinder by pulling the overlapped portion of the incision edge to the inside by the shape recovery effect of the shape memory spring attached to the inside of the cylinder. According to this configuration, for example, the cylinder can be reduced in diameter and demolded from the concrete by a simple operation of heating the shape memory spring from the vicinity of the opening end of the cylinder with a hair dryer or the like.
[0011]
Further, the diameter reducing means (third diameter reducing means) according to the configuration of claim 3 includes at least a pair of protrusions attached to the inner surface of the cylindrical body with the overlapping portion of the incision edge interposed therebetween, It is characterized in that the distance between the protrusions is reduced by applying a force in a direction in which the protrusions approach each other to each protrusion.
[0012]
According to this diameter reducing means, the diameter of the cylinder can be reduced by simply bringing the protrusions on the inner surface of the cylinder facing each other across the overlapped portion of the incision edge, for example, by bringing them close to each other with a fingertip or an appropriate tool. Can be demolded from concrete.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0014]
<First embodiment>
1 to 2 show a form material 1A for forming a through hole according to the first embodiment of the present invention.
[0015]
The cylindrical body 2 serving as the mold body of the through hole is a member made of a material having moderate elasticity and flexibility, such as a thin metal plate or a synthetic resin plate, and a part of the cylinder opened at both ends is in the axial direction. And the incision edges are superposed with an appropriate width (about 3 to 10% of the circumference). The cylindrical body 2 may be formed by cutting a pipe material or may be formed by winding a plate material. The overlapped portion 21 at the incision edge is in close contact with the cylinder 2 as a whole so that the concrete trowel does not enter, but is not fixed. The cylindrical body 2 is formed to have the same length as the facing interval of the barrier plates F constituting the mold and is fixed in the mold. In addition, it is preferable to apply a mineral oil-based concrete release agent to the outer surface of the cylindrical body 2.
[0016]
In this embodiment, a first diameter reducing means using a six-node parallel crank mechanism is provided inside the cylindrical body 2. The diameter-reducing means includes a diameter-reducing lever 31 arranged in the axial direction of the cylindrical body 2 and four link arms 32 pivotally attached to the diameter-reducing lever 31. The diameter-reducing lever 31 is formed to have a length that is substantially the same as or slightly shorter than the length of the cylindrical body 2, and is disposed in the vicinity of the middle between the central axis 20 of the cylindrical body 2 and the overlapping portion 21 at the incision edge. ing.
[0017]
Two link arms 32 are pivotally mounted in the vicinity of both end portions of the diameter-reducing lever 31 so as to be swingable via appropriate pin members. Each link arm 32 has the same length. The two link arms 32 face opposite to each other at the axis attachment points 33 of the diameter-reducing lever 31 and the link arm 32, and the distal ends of the link arms 32 face each other across the overlapping portion 21 of the incision edge. It is attached to the inner surface of the cylindrical body 2 via an appropriate pin member. As shown in FIG. 2A, the four pivot attachment points 34 on the cylindrical body 2 side are set so that each link arm 32 is orthogonal to the diameter reducing lever 31 without applying an external force to the diameter reducing lever 31. Has been. In this state, the through hole forming mold material 1A is fixed in the mold, and concrete C is placed.
[0018]
When the mold material 1A for forming the through hole is fixed in the mold, for example, an end cap 6 as shown in FIG. May be fitted to both ends of the cylindrical body 2. The illustrated end cap 6 includes a short cylindrical portion 61 that matches the inner diameter of the cylindrical body 2, and a disk-shaped flange portion 62 that matches the outer diameter of the cylindrical body 2. A round hole 63 for facilitating attachment / detachment operation to / from the cylindrical body 2 is formed. Such an end cap 6 can also be used in second and third embodiments described later.
[0019]
When removing the through-hole forming mold member 1A, as shown in FIG. 2B, the diameter-reducing lever 31 is pulled or pushed in the axial direction from the vicinity of one opening end of the cylindrical body 2 to Move in the direction. Then, the swing angle of the link arm 32 with respect to the diameter-reducing lever 31 is changed, the pivot point 34 on the cylindrical body 2 side is drawn inward, the overlapping width of the incision edge is increased, and the cylindrical body 2 is contracted. Diameter. Thus, the cylinder 2 can be easily peeled from the concrete C.
[0020]
Thus, since the first diameter reducing means constituting the through hole forming mold material 1A of the present invention uses a simple and rational parallel crank mechanism, it can be easily manufactured. The operation is also easy, and the diameter of the cylindrical body 2 can be reliably reduced. In addition, when the cross-sectional proportion of the cylinder 2 is further elongated, the diameter of the cylinder 2 can be reduced evenly in the length direction by adding the link arm 32 to the intermediate portion in the axial direction.
[0021]
<Second embodiment>
3 to 4 show a form material 1B for forming a through hole according to the second embodiment of the present invention. In this embodiment, a second diameter reducing means using a shape memory spring 41 is provided inside the same cylinder 2 as the cylinder 2 shown in the first embodiment. The shape memory spring 41 is disposed in the vicinity of both end portions of the cylindrical body 2 and orthogonal to the axial direction of the cylindrical body 2. The position of the shape memory spring 41 when viewed from the axial direction of the cylindrical body 2 is preferably near the middle between the central axis 20 of the cylindrical body 2 and the overlapped portion 21 of the incision edge. Both ends of the shape memory spring 41 are respectively connected to the inner surfaces of the cylindrical body 2 facing each other with the overlapping portion 21 of the incision edge interposed therebetween via appropriate latching members 42.
[0022]
The shape memory spring 41 holds the cylinder 2 according to the design dimension of the through hole at room temperature, but when heated, the distance between both ends is reduced by the shape recovery effect, and the cylinder 2 is drawn inward to reduce the diameter. Is formed. Therefore, at the time of demolding, the cylindrical body 2 can be easily peeled from the concrete C by heating the shape memory spring 41 from the vicinity of the opening end of the cylindrical body 2 with, for example, a hair dryer.
[0023]
In addition, when the cross-sectional proportion of the cylindrical body 2 is further elongated, the cylindrical body 2 can be uniformly reduced in diameter in the length direction by adding the shape memory spring 41 to the intermediate portion in the axial direction. . Further, in this diameter reducing means, the shape of the shape memory spring 41 itself is not limited to the coil shape as illustrated. For example, a plate-like spring may be bent at an appropriate angle to reduce the distance between both ends.
[0024]
<Third embodiment>
5 to 6 show a through hole forming mold member 1C according to the second embodiment of the present invention. In this embodiment, a third diameter reducing means comprising at least a pair (two pairs in this example) of protrusions 51 is provided inside the same cylinder 2 as the cylinder 2 shown in the first embodiment. Yes. The pair of projecting portions 51 are attached in the vicinity of both end portions of the cylindrical body 2 so as to face each other with the overlapping portion 21 of the incision edge portion interposed therebetween. When removing the mold, a force is applied from the vicinity of the opening end of the cylindrical body 2 to the direction in which the pair of protruding portions 51 are close to each other (the left-right direction in FIG. 5) using a tool such as a fingertip or pliers. . Then, the distance between the protrusions 51 is reduced, the overlapping width of the incision edge is increased, and the cylindrical body 2 is reduced in diameter. The cylindrical body 2 can be easily removed from the mold by such a diameter reducing means.
[0025]
【The invention's effect】
According to the form material for forming a through hole having the first diameter reducing means using the six-node parallel crank mechanism, the simple diameter operation can be performed simply by operating the diameter reducing lever from the vicinity of one opening end of the cylindrical body. Then, the overlapping portion of the incision edge can be drawn inward to reduce the diameter of the cylindrical body and demold from the concrete.
[0026]
Further, according to the through hole forming form member having the second diameter reducing means using the shape memory spring, the shape memory spring is heated by a hair dryer or the like from the vicinity of the opening end of the cylindrical body. The cylinder can be reduced in diameter and demolded from the concrete.
[0027]
In addition, it is possible to easily reduce the diameter of the cylinder and demold it from the concrete by means of a through-hole forming mold member provided with a third diameter reducing means that uses a projecting portion facing each other across the overlapping portion of the incision edge. Can be made.
[0028]
Thus, according to the form material for forming a through hole of the present invention, even when the diameter of the through hole is small and manual operation inside the cylinder is not possible, it is possible from the vicinity of the opening end of the cylinder. Since the diameter of the cylindrical body can be reduced uniformly over almost the entire length with a simple operation, the work for removing the mold material is further facilitated.
[Brief description of the drawings]
FIG. 1 is a front view of a through-hole forming mold material according to a first embodiment of the present invention when viewed from the axial direction.
FIGS. 2A and 2B are side views of the form material for forming a through hole in FIG. 1, in which FIG. 2A shows a state when placing concrete, and FIG. 2B shows a state when demolding.
FIG. 3 is a front view of a through hole forming mold member according to a second embodiment of the present invention when viewed from the axial direction.
FIGS. 4A and 4B are side views of the form material for forming a through hole in FIG. 3, in which FIG. 4A shows a state when placing concrete, and FIG. 4B shows a state when demolding.
FIG. 5 is a front view of a through hole forming mold member according to a third embodiment of the present invention when viewed from the axial direction.
6A and 6B are side views of the form material for forming a through hole in FIG. 5, in which FIG. 6A shows a state when placing concrete, and FIG. 6B shows a state when removed.
FIG. 7 is a perspective view of an end cap used in combination with the through hole forming form material of the present invention.
[Explanation of symbols]
1A Forming material for forming a through hole 1B Forming material for forming a through hole 1C Forming material for forming a through hole 2 Cylindrical body 20 Center shaft 21 Overlapping point 31 Reduced diameter lever 32 Link arm 41 Shape memory spring 51 Projection

Claims (3)

A cylindrical body made of an elastically deformable flexible material is cut in the axial direction, the cut edge is overlapped with an appropriate width and held in a cylindrical shape, and the diameter of the cylindrical body is reduced inside this cylindrical body. A form material for forming a through hole provided with means,
The diameter-reducing means includes a diameter-reducing lever arranged in the axial direction of the cylindrical body, and two link arms that are axially attached in the vicinity of both ends of the diameter-reducing lever. A through-hole characterized in that the distance between the tip ends of the link arms is reduced by being axially attached to the inner surface of the opposite cylindrical body across the overlapping portion of the edge and operating the diameter-reducing lever in the axial direction. Form material for hole formation. A cylindrical body made of an elastically deformable flexible material is cut in the axial direction, the cut edge is overlapped with an appropriate width and held in a cylindrical shape, and the diameter of the cylindrical body is reduced inside this cylindrical body. A form material for forming a through hole provided with means,
The diameter reducing means includes at least two or more shape memory springs arranged in a direction orthogonal to the axis of the cylinder, and both ends of the shape memory spring are opposed to each other with the overlapping portion of the incision edge interposed therebetween. A through hole forming form material characterized in that it is connected to each surface and formed so that the distance between both ends of the shape memory spring is reduced upon heating. A cylindrical body made of an elastically deformable flexible material is cut in the axial direction, the cut edge is overlapped with an appropriate width and held in a cylindrical shape, and the diameter of the cylindrical body is reduced inside this cylindrical body. A form material for forming a through hole provided with means,
The diameter-reducing means includes at least a pair of protrusions attached to the inner surface of the cylinder with the overlapping portion of the incision edge interposed therebetween, and a force in a direction in which the protrusions approach each other. A form material for forming a through hole, which is formed so that the distance between the protrusions is reduced by acting.

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