JPH0749694B2 - Hollow precast concrete member and centrifugal concrete forming machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention has a hollow pre-cast concrete member having a hollow rectangular cross-section, and main bars can be arranged afterward, and such a hollow column. The present invention relates to a centrifugal concrete molding machine for obtaining a precast concrete member.

<< Prior Art >> In recent years, precast concrete has been used for high-rise buildings because of its high construction efficiency of reinforced concrete structures and the production of high-quality concrete products.

In addition, there is an increasing number of cases where a precast concrete hollow columnar body is used to axially connect and connect columns / beam joints of precast concrete columns and columns to each other.

Such hollow pillars are generally made with a centrifugal concrete molding machine.When concrete is poured into the form while rotating the form, the concrete will adhere tightly to the inner wall surface of the form due to centrifugal force. It is cured as it is to obtain a hollow columnar body.

The above-mentioned mold is generally cylindrical because it is rotated.

<< Problems to be solved by the invention >> However, the pillars of a building are usually formed in a rectangular cross section, and there is no one in which a pillar formwork assembled in a cubic shape is rotated by a centrifugal molding machine. .

The present invention has been made in view of the circumstances described above,
The purpose thereof is to facilitate the joining with other members, so that a hollow precast concrete member having a rectangular cross section in which a rebar having an arbitrary shape and an arbitrary length can be arranged later and a centrifugal concrete capable of molding such a hollow precast concrete member. To provide a molding machine.

<< Means for Solving the Problem >> The hollow precast concrete member of the present invention is a concrete member manufactured by centrifugal molding, in which the outer peripheral surface is formed into a rectangular cross section having corners and the inner peripheral surface is circular in cross section. It is characterized in that it is formed into a hollow cylindrical body having a closed cross section by forming a corner portion along the shape of the corner portion of the outer peripheral surface at a position on the inner peripheral surface inside the corner portion of the outer peripheral surface.

Further, in this hollow precast concrete member, a hoop streak can be arranged in the thick portion of the concrete material forming the outer peripheral surface and the inner peripheral surface.

Further, the centrifugal concrete molding machine according to the present invention includes a formwork formed in a box-like shape having a rectangular cross section and horizontally placed, and a disk attached to the formwork with its center aligned with the center of the cross section of the formwork. In a centrifugal concrete molding machine provided with a drive wheel that rotationally drives the disk to rotate the mold, in a corner portion of the mold, along the longitudinal direction thereof, and from the inner surface of the mold. It is characterized in that the rods are arranged at intervals.

<Operation> To describe the operation of the present invention, the hollow precast concrete member is manufactured with high strength and high quality due to good compaction of the concrete material, which is an advantage of the centrifugal molding method.
In addition, the finished surface is fine and there is no need to apply a finishing base. Further, since it has high strength, the wall thickness of the concrete material can be reduced, and a crane or the like having a small capacity can be used due to such thinning and weighing. On the other hand, since it has high strength, it can sufficiently withstand the lateral pressure of the concrete placed therein, cracks and the like do not occur, and supporting work is not required. And since no support work is required, work efficiency can be improved. Furthermore,
Since it is a driven formwork that can be used directly as a structural material, it saves labor in the formwork on-site, eliminates the need to remove the formwork, and disposes of the generated material.

On the other hand, by providing the hoop streak, it is possible to manufacture with higher rigidity, and it is also possible to reduce the wall thickness of the concrete material to reduce the weight. Further, by disposing the hoop reinforcements in the thick wall portion of the concrete material from the time of manufacturing, the reinforcement work at the site can be performed only by the main reinforcements, and the work can be simplified. Furthermore, since the hoop muscles are laid out at the time of manufacturing, the hoop muscles can be laid out more accurately than when arranging the hoop muscles on site.

Further, in the centrifugal concrete molding machine of the present invention, the box-shaped form frame having a rectangular cross section and the disk are concentric, and when the disk is rotated, the form also rotates integrally. An even centrifugal force works inside. When concrete is added while rotating the mold, the concrete is solidly pressed and urged against the inner wall of the mold by centrifugal force and solidifies. In particular, in the present invention, the rods arranged in the corners of the mold along the longitudinal direction thereof and at a distance from the inner surface of the mold should be inserted into the mold in advance. This rod is held in the corner position in the mold by the action of centrifugal force, and is fixed in its original position by the poured concrete,
The hollow precast concrete member is manufactured in this state. The corners of this form correspond to the positions of the main bars such as the column main bars, and when this rod is removed after molding,
It is possible to obtain a hollow precast concrete member provided with a molding portion in which main bars to be inserted later can be appropriately arranged.

Since the end surface of the manufactured hollow precast concrete member is formed with a disc surface with high accuracy, it is possible to secure sufficient installation accuracy simply by placing the end surface at the installation position.
From this aspect as well, work can be performed efficiently.

«Examples» Hereinafter, preferred examples of the present invention will be described in detail with reference to the drawings.

The hollow precast concrete member 12 of the present invention is basically a concrete member produced by centrifugal molding, in which the outer peripheral surface is formed into a rectangular cross section having corners and the inner peripheral surface is formed into a circular cross section, and Corners along the shape of the corners of the outer peripheral surface at the inner peripheral surface position inside the corners of the outer peripheral surface 13
Is formed to have a closed-section hollow cylindrical shape.

The hoop streak 6 may be formed in the thick portion of the concrete material forming the outer peripheral surface and the inner peripheral surface.

The centrifugal concrete molding machine 7 according to the present invention includes a mold 2 formed in a box shape having a rectangular cross section and horizontally placed, and a mold 2
The disk 3 is attached to the mold 2 with its center aligned with the cross-sectional center of the disk 3, and the drive wheel 10 for rotating the disk 3 to rotate the frame 2, and the corners of the frame 2 are provided. Is provided with a rod body 4 along its longitudinal direction and at a distance from the inner surface of the mold 2.

FIG. 1 shows an outline of the formwork apparatus 1. This formwork device 1 was inserted into the formwork 2 and a formwork 2 having a rectangular cross section, which was constructed by firmly assembling a panel into a square cube, a disc 3 having an opening into which the formwork was fitted. The rod body 4 has a right-angled triangular cross section.

The mold 2 needs to have a strength sufficient to withstand the centrifugal force of the concrete put inside during rotation. And this formwork 2
The discs 3 are fitted to both ends of the mold 2 so that the axial center (the cross-sectional center) of the disc and the center of the disc 3 are aligned with each other.

The mold 2 is rotated by rotating the disk 3.

Further, in the formwork 2, a rod body 4 having a right-angled triangular cross section is previously prepared.
Insert this book. This is to be accommodated in the corners of the mold 2 by relying on the centrifugal force when the mold 2 is rotated.

The details are shown in FIG. 2 in the direction of the line II-II in the figure.

A doughnut-shaped spacer (commonly referred to as a donut) 5 is fitted in the mold 2 and a hoop muscle 6 is arranged at an appropriate distance from the inner wall surface of the mold 2.

FIG. 3 shows the centrifugal concrete molding machine 7 and the formwork apparatus 1 together, and the centrifugal concrete molding machine 7 has rotating wheels 8-8a arranged at intervals on the left and right, and one rotating wheel 8
Is connected to a drive wheel 10 attached to the output shaft of the motor 9 by a belt 11.

Then, when manufacturing a rectangular column which is a hollow precast concrete member, the formwork apparatus 1 places the part of the disk 3 between the rotating wheels 8-8a of the molding machine 7 and places it horizontally.

Then, concrete is poured into the inside of the mold 2 and both end surfaces of the mold 2 are closed. To close it, an iron plate or a plate material is screwed to the side surface of the mold 2.

The concrete may be poured from the side surface of the formwork 2, or an opening that can be closed in a part of the formwork 2 may be provided, but the center of the iron plate that closes the side end surface of the formwork 2 may be used. Connect the concrete pumping hose to the rotatably,
After the rod 4 is rotated to move to the corner by centrifugal force, concrete is added while further increasing the rotation speed.

The centrifugal force causes the concrete to agglomerate and the excess water is drained from the edges of the formwork. It is desirable to drain as much excess water as possible during rotation to obtain high quality concrete.

When the concrete is almost solidified, the centrifugal concrete molding machine 7 is stopped and the mold is removed. When demolded, a product as shown in FIG. 4 is obtained. This is a quadrangular prism 12 having a cylindrical space inside due to centrifugal force.

Then, by pulling out the rods 4 located at the four corners, the rods 4 are placed inside the quadrangular prism 12 along the axial direction thereof.
A spline-shaped notch 13 having a rectangular cross section that matches the outer shape of is formed. Since the notches 13 match the positions where the column main bars 14 are arranged, the column main bars 14 can pass through the respective notches 13. Further, since a continuous and sufficient wall thickness can be secured along the circumferential direction of the quadrangular prism 12, high strength can be obtained. If a Teflon coating film is applied to the surface of the rod 4 or an edging agent such as oil or fat is applied, it can be easily extracted later.

Explaining the shape of the quadrangular prism 12 in more detail, the outer peripheral surface is formed into a rectangular cross-section having a corner portion, the inner peripheral surface is formed into a circular cross-section, and the inner peripheral surface that is inside the corner portion of the outer peripheral surface. A notch 13 is formed at the position along the shape of the corner of the outer peripheral surface to form a hollow cylinder having a closed cross section. Also,
A hoop streak 6 (not shown) is provided in the thick portion of the concrete material forming the outer peripheral surface and the inner peripheral surface.

Next, another embodiment of the present invention will be described.

FIG. 5 is an end view of the same portion as the portion indicated by the line II-II in FIG. 1, in which the rectangular prism 12a has a rectangular cross-section.
The rod body 4a is substantially the same as the above-described embodiment except that the rod body 4a has a sectoral shape as compared with the rod body 4 described above. Therefore, only the differences will be described below.

First, mount the rod body 4a having a fan-shaped cross section into the formwork 2 to form a square pole 12
The mold 2 is rotated while inserting concrete into the mold 2 so that the thickness a of the short side of a becomes a required thickness.

Since the thickness b of the long side of the quadrangular prism 12a becomes thin when the concrete has hardened to a certain extent in (1) of the figure,
The form 2 is rotated while adding concrete so that this portion has the required thickness (Fig. (2)).

Figure (3) in the figure is the same as Figure (2).
A bar 4a having a fan-shaped cross section and a mold 2 are demolded, and a rectangular column 12a having a rectangular cross section having notches 13 at four corners is obtained.

The square columns 12 and 12a manufactured as described above have good compaction properties of the concrete material, which is an advantage of the centrifugal molding method.
It is manufactured with high strength and quality, and the finished surface is dense, eliminating the need for finishing. Further, since it has high strength, it is possible to reduce the thickness of the concrete material, and it is possible to use a crane or the like having a small capacity by reducing the thickness and weight. On the other hand, since it has high strength, it can sufficiently withstand the lateral pressure of the concrete placed therein, cracks and the like do not occur, and supporting work is not required. And since no support work is required, work efficiency can be improved. Furthermore, since it is a driven formwork that can be used directly as a structural material, labor saving of formwork at the site, demolding work of the formwork are unnecessary, and disposal of the generated material is also unnecessary.

On the other hand, by disposing the hoop streak 6, it is possible to manufacture with higher rigidity, and it is also possible to reduce the wall thickness of the concrete material to reduce the weight. Further, by disposing the hoop reinforcement 6 in the thick portion of the concrete material from the time of manufacturing, the reinforcement work on site can be performed only with the main reinforcement 14 and the like, and the work can be simplified. Furthermore, since the hoop muscles 6 are arranged at the time of manufacturing, it is possible to arrange the hoop muscles more accurately than when the hoop muscles are arranged on site.

Since the end faces of the manufactured quadrangular prisms 12 and 12a are formed with high precision on the disc surface of the disk 3, it is possible to secure sufficient installation precision simply by placing the end faces at the installation position, and work efficiently from this aspect as well. Can be done.

<Effect> According to the present invention required as described above, the following excellent effects are exhibited.

(1) Due to the good compaction property of the concrete material, which is an advantage of the centrifugal molding method, it is manufactured with high strength and high quality, and the finished surface is dense and there is no need to apply a finishing base. Further, since it has high strength, it is possible to reduce the thickness of the concrete material, and it is possible to use a crane or the like having a small capacity by reducing the thickness and weight. On the other hand, because of its high strength, it can withstand the lateral pressure of the concrete placed inside it and does not crack, etc.
No support work required. And since no support work is required, work efficiency can be improved. Furthermore, since it is a driven formwork that can be used directly as a structural material, labor saving of formwork at the site, demolding work of the formwork are unnecessary, and disposal of the generated material is also unnecessary.

(2) By arranging the hoop streak, it is possible to manufacture with higher rigidity, and it is also possible to reduce the wall thickness of the concrete material to reduce the weight. Further, by disposing the hoop reinforcements in the thick wall portion of the concrete material from the time of manufacturing, the reinforcement work on site can be performed only with the main reinforcements and the like, and the work can be simplified. Furthermore, since the hoop muscles are laid out at the time of manufacturing, the hoop muscles can be laid out more accurately than when arranging the hoop muscles on site.

(3) According to the formwork apparatus of the present invention, since the formwork having a rectangular cross section is supported by the disk at the coaxial position, the disk part of the formwork is mounted on the rotary wheel or the drive wheel of the centrifugal concrete molding machine. Since the turning force can be applied by putting it on, it is possible to form a solid precast concrete member with a rectangular cross section that is solid and has excellent strength without using a double formwork provided with an inner formwork or the like. .

In addition, since the rod is inserted into the formwork and the centrifugal force is used to fit it from the inner surface of the formwork to the corners, it is not necessary to lock it in the formwork, and it can be used after placing concrete. Make it easy to pull out. In particular, in the present invention, the rods arranged in the corners of the mold along the longitudinal direction thereof and at a distance from the inner surface of the mold should be inserted into the mold in advance. This rod is held at the corner position in the mold by the action of centrifugal force, and is fixed in that position by the injected concrete, and the hollow precast concrete member is manufactured in this state. It The corners of this form corresponded to the positions of the main bars such as the column main bars, and were equipped with a molded part that could appropriately arrange the main bars that will be inserted later if this rod is removed after molding. A hollow precast concrete member can be obtained. That is, in the notch in the corner of the precast concrete member that remains after pulling out the rod, there is a column main bar of any length according to the situation of the site, and its diameter is also arbitrarily selected and appropriate concrete Since the reinforcement can be arranged with the covering thickness, it is convenient for joining column / beam joints, and it is possible to provide a hollow precast concrete member that is most suitable for construction using precast concrete. Furthermore, it is also possible to form a hollow precast concrete member with a rectangular cross section, and the notch formed in the corner of this hollow part has the optimum shape for passing the main bar by selecting the cross sectional shape of the rod. There is an effect that can be done.

(4) Since the end surface of the manufactured hollow precast concrete member is formed with a disc surface with high accuracy, it is possible to secure sufficient installation accuracy simply by placing the end surface at the installation position, and work efficiently from this surface as well. Can be done.

[Brief description of drawings]

Each of the drawings relates to an embodiment of the present invention, FIG. 1 is a perspective view showing a mold device of a centrifugal concrete molding machine, FIG. 2 is an end view taken along the line II-II of FIG. 1, and FIG. Is a side view illustrating a state where the formwork device is arranged in the centrifugal concrete molding machine,
FIG. 4 is a perspective view showing a hollow precast concrete member according to the present invention, and FIG. 5 shows a cross section of a formwork apparatus according to another embodiment, and the usage process thereof is sequentially described in (1) to (3). It is sectional drawing shown in FIG. 1 ... Formwork device, 2 ... Formwork 3 ... Disk, 4 ... Rod 5 ... Spacer 6 ... Hoop muscle 7 ... Centrifugal concrete molding machine 8 ... Rotating wheel 9 ... Motor 10 ... Drive wheel 11 …… Belt 12,12a …… Hollow precast concrete member (square column) 13 …… Corner (notch) 14 …… Column main bar

Front Page Continuation (72) Inventor Koji Hamada 4-640 Shimoseido, Kiyose-shi, Tokyo Inside Obayashi Technical Research Institute Co., Ltd. (56) Bibliography Sho 49-69717

Claims (3)

[Claims] 1. A concrete member manufactured by centrifugal molding, wherein the outer peripheral surface is formed into a rectangular cross section having corners, the inner peripheral surface is formed into a circular cross section, and the inner side of the corner of the outer peripheral surface is formed. A hollow precast concrete member, characterized in that a corner portion is formed at a position corresponding to the corner portion of the outer peripheral surface at the inner peripheral surface position, and the hollow precast concrete member has a closed cross-section. 2. The hollow precast concrete member according to claim 1, wherein a hoop streak is arranged in the thick portion of the concrete material forming the outer peripheral surface and the inner peripheral surface. 3. A mold which is formed in a box-like shape having a rectangular cross section and is placed horizontally, a disk which is attached to the mold with its center aligned with the center of the cross section of the mold, and the mold is rotated. In a centrifugal concrete molding machine provided with a drive wheel for rotationally driving the disk, a rod body is provided at a corner portion of the mold along its longitudinal direction and at a distance from an inner surface of the mold. The centrifugal concrete molding machine is characterized in that.