JPH0347073Y2 - - Google Patents

Description

[Detailed description of the invention] "Field of industrial application" The invention relates to a formwork holding structure for accurately maintaining the distance between formworks, and in particular, the cones provided at both ends of the separator are formed of ceramics. This invention relates to a formwork holding structure.

``Prior art'' Conventionally, this type of formwork holding structure has consisted of separators (round separators) that tighten the weir plates that make up the formwork at predetermined intervals, and connecting materials (form ties) that fix the separators to end pieces. (registered trademark)) and a cone (joint fitting) for connecting the separator and the connecting material, a cone that hits the weir plate is attached to both ends of the separator, and the separator is arranged between the weir plates, A configuration in which a connecting shaft (spindle) is screwed into the cone and the connecting material is connected to this connecting shaft is widely used.

"Problems to be Solved by the Invention" The formwork holding structure described above does not cause bulges in the formwork and can form concrete with high precision. However, even with this formwork holding structure, there is still room for consideration in the following points, for example.

When a cone is extracted (removed) from a concrete structure after concrete has hardened, it is troublesome to treat the hole left by the cone, for example, by filling it with mortar etc., and the workability is poor.

If the outer periphery of the iron cone is covered with plastic and the cone is buried in concrete, the post-burying process can be omitted, but on the other hand, there are problems caused by the fact that the cone itself is made of metal such as iron. This corrosion causes problems such as cracks in the concrete and staining of the concrete due to rust fluid. In addition, due to deterioration or shrinkage of the plastic covering the outer periphery of the cone, gaps may form between the concrete and the cone, and the separator may corrode due to water intrusion from the outside.

Therefore, as a result of intensive research to solve these problems, the present applicant and others have found that if the cone is made of ceramics, the cone itself will not corrode even if it is buried, and the deterioration of concrete will be prevented. In addition to improving its durability, it can also block water from entering from the outside.
In addition, we came up with the idea that it is easy to manufacture.

However, simply replacing the cone material with ceramics instead of conventional metal or plastic would make it difficult to put it into practical use because ceramic cones are brittle against tensile forces. There is a problem.

The object of the present invention is to provide a new formwork holding structure that can effectively solve the above-mentioned problems, and is a formwork holding structure with improved applicability to ceramic cones.

"Means for solving the problem" The present invention provides a separator that maintains the distance between the weir plates of the formwork, and connects cones that touch the weir plates to both ends of the separator, and The formwork holding structure has one end of the joint shaft connected to the other end of the cone, and the entire cone is made of ceramics, and an outer periphery of the cone has an outer diameter slightly smaller than the outer diameter of the cone coaxially with the cone. It is characterized by the fact that the tubes are fitted together by shrink fitting.

"Function" In the formwork holding structure having the above configuration, the outer cylinder attached to the outer periphery of the cone by shrink fitting tightens the cone strongly by shrinking after cooling, so that the cone is tightly tightened during concrete pouring. Compressive force acts on the part of the cone where the tensile force acts the most, and this compressive force cancels out the tensile force that occurs in the cone during concrete placement, reducing the tensile force that causes cracks and splitting. It generates almost no force and can provide sufficient proof strength.

"Embodiment" Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

Also in this embodiment, as shown in FIG.
A separator (round separator) 2 with a male thread 2a is provided between the weir plates 1 of the formwork to maintain the distance between the weir plates 1, and the separator 2 has a weir plate at both ends (only one is shown). 1 is connected to the cone 3 by screwing, one end of a connecting shaft 4 is screwed to the cone 3, and the separator 2 is connected to a connecting material (form tie) attached to the other end of the connecting shaft 4. ) 5 and the washer 6 on the seat plate (wood seat) 7 (steel pipe in the illustrated example).
8 is the same as the conventional example of this type of formwork holding structure, but it differs greatly in the following points.

That is, the entire cone 3 that connects the separator 2 and the coupling shaft 4 is formed of ceramics, and an outer cylinder 1 having an inner diameter slightly smaller than the outer diameter of the cone 3 is disposed coaxially with the cone on the outer periphery of the cone 3.
0 is a structure in which they are fitted together by shrink fitting.

Next, to explain these in detail, the cone 3 is made of ceramic and has a cylindrical shape as a whole, and a first screw hole 11 into which the separator 2 is screwed is formed in one end surface (the right end surface in the figure). At the same time, a second screw hole 12 into which the coupling shaft 4 is screwed is provided on the other end surface. These 2
A partition wall 13 is provided between the two screw holes 11 and 12 to partition them, to prevent water from seeping in from the outside through the screw hole 11.

The outer cylinder 10 fitted around the outer periphery of the cone 3 is made of iron,
It is made of metal such as stainless steel and has a cylindrical shape shorter than the length of the cone 3, and is integrally fitted into the center of the cone 3. Further, the fitting position of the outer cylinder 10 is set so as to cover the outer side from a position shifted outward by about 45 degrees from the peripheral edge of the partition wall 13 as a reference point. This is because the cracks caused by tension extend in a direction of about 45 degrees. An O-ring 14 made of inflatable rubber or the like is provided on the outer periphery of the cone 3 at the end of the outer cylinder 10 (left end in the figure) to prevent water from leaking from the outer periphery of the cone 3. There is.

In addition, to supplement the explanation of the connecting material 5, a male thread 5a for screwing together a nut 15 for fixing the washer 6 is provided on the outer peripheral surface of one end of the connecting material 5, and a connecting shaft is provided at the other end. 4 is inserted into the screw hole, and a female thread 5b is formed on the inner circumferential surface thereof to be screwed into the male thread 4a of the coupling shaft 4.

Next, the operation of this embodiment configured as above will be explained.

In assembling the formwork, first, the cone 3 is screwed onto the external thread 2a of the separator 2, and then the weir plates 1 are arranged to face each other, and the separator 2 is disposed between these weir plates 1. At this time, by relatively rotating the separator 2 and the cone 3, the position of the cone 3 is moved and fine adjustment between the weir plates 1 is performed.

Then, the weir plate 1 is passed through the second screw hole 12 of the cone 3 and the connecting shaft 14 is screwed together, and the connecting material 5 is screwed to the male thread 4a at the other end of the connecting shaft 4. is fixed from above the seat plate 7 to the thick material (steel pipe) 8 with the washer 6, resulting in the assembled state shown in the drawing.

In the formwork holding structure according to this embodiment, the outer cylinder 10 having an inner diameter slightly smaller than the outer diameter of the cone 3 is attached to the outer circumference of the cone 3 by shrink fitting, so that a tensile force is applied to both ends of the cone 3. When this occurs, a compressive force due to the contraction of the outer cylinder 10 acts on the part that is weakest in tension (the part of the partition wall 13 in the illustrated example), and for example, when pouring concrete, a compressive force is applied to the cone 3 as a tensile force. Even if a load of It is possible to exhibit a high yield strength and improve the applicability to the use of the ceramic cone 3.

Incidentally, since the cone 3 is considerably lighter than metal such as iron, it also has the advantage of being easy to handle when arranging the separator 2 and the like.

In addition, after dismantling the formwork, the ceramic cone 3
A ceramic cap (plug) is attached to the second screw hole 12 to prevent water from entering the screw hole. In particular, a partition wall 13 is formed in the ceramic cone 3. Therefore, water will not enter the separator 2.

Figure 2 shows another embodiment of the present invention.
In place of the male-threaded separator and coupling shaft 4 shown in FIG. 1, etc., a separator 26 and coupling shaft 27 having a protruding locking convex portion 25 extending left and right (up and down in FIG. 2) at the tip are installed on the partition wall. 13 is connected to a ceramic cone 30 having locking holes 28 formed on both sides thereof to engage with the locking protrusions 25.

Here, the locking portion 28a of the locking hole 28 is formed at a position shifted from the insertion hole 28b of the locking convex portion 25 by 90 degrees in the circumferential direction. And separator 26
and to connect the connecting shaft 27 with the cone 30,
After inserting these all the way through the insertion hole 28b of the locking hole 28, the locking convex portion 25 may be engaged with the locking portion 28a by rotating 90 degrees.

Note that this embodiment can also provide the same effects as those of the previous embodiment.

Further, in the present invention, the shape of the cone 3 is not limited to the illustrated example, and a suitable rib or the like may be provided on the outer periphery of the cone to ensure that the cone does not come off.

In addition, in the present invention, since the cone 3 is usually formed mainly from alumina raw material (white),
Although the cone 3 has a white appearance, it can be colored by mixing a metal pigment into the raw materials. In addition, we are currently conducting extensive research to further clarify the details of the type of pigment used to color the cone 3 in a gray color.

"Effects of the Invention" As explained above, the present invention provides the following excellent effects.

(a) Since the separator is made of ceramic cones that are placed at both ends of the separator and touch the weir plates, even if the cones are buried, corrosion in the concrete will not occur, and the concrete of the concrete structure will deteriorate after forming. can be prevented. Further, if a partition wall is formed inside the ceramic cone to block the screw hole (or insertion hole), it is possible to reliably block water from entering from the outside and prevent corrosion of the separator.

(b) The outer cylinder attached to the outer circumference of the cone by shrink fit shrinks after cooling, tightening the cone strongly and applying compressive force to the part of the cone where tensile force is generated. The compressive force cancels out the tensile force that is generated in the cone during concrete placement, so there is almost no tensile force that can cause cracks or splits, and sufficient strength can be obtained.

(c) As described above, since compressive force is mainly applied to the ceramic cone, the applicability of the ceramic cone to practical use can be improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is a sectional view of essential parts showing another embodiment of the present invention. 1... Weir plate, 2... Separator, 2a... Male thread, 3... Cone, 4... Connection shaft, 5... Connecting material, 6... Washer, 8... Thick material, 10... Outside Cylinder, 11...First screw hole, 12...Second screw hole, 13...Partition wall, 14...O ring, 15
...Natsuto.

Claims (1)

[Claims for Utility Model Registration] 1. A separator is provided between the weir plates of the formwork to maintain the distance between the weir plates, and cones that touch the weir plates are connected to both ends of the separator, and the other end of the cone The formwork holding structure has one end of a joint shaft connected to the cone, and the cone is entirely formed of ceramics, and has an inner diameter slightly smaller than the outer diameter of the cone coaxially on the outer periphery of the cone. A formwork holding structure characterized in that the outer cylinder is integrally fitted by shrink fitting. 2 The cone is formed in a cylindrical shape, and has a first screw hole formed in one end surface thereof to which the separator is screwed, and a second screw hole to which one end of the coupling shaft is screwed to the other end surface. A hole is provided, a partition wall is provided between these two screw holes to partition them, and the outer cylinder is positioned on the outer periphery of the cone on which the partition wall is formed and is fitted together by shrink fitting. The formwork holding structure according to claim 1 of the utility model registration claim, characterized in that: