JP2525332B2 - Manufacture method for bottom mold of manhole and bottom mold of manhole - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a manhole bottom block forming die and a manhole bottom block forming die,
In particular, the present invention relates to a method for manufacturing a manhole bottom block molding die for manufacturing a manhole bottom block block having a groove-like invert on the inner bottom surface thereof, and a manhole bottom block molding die.

[0002]

2. Description of the Related Art Generally, a manhole is formed of a concrete molded body. For example, as shown in FIG. 6, a bottom block 1 is fixed on a bottom plate 6, and a cylindrical straight wall is mounted on the bottom block 1. 7
Are overlapped and joined together in a required number, and a slanted wall 9 provided with a lid 8 on the top is joined together. As shown in FIG. 7, the bottom block 1 is formed into a cup shape having a bottom wall 2 and a side wall 3, and a groove-shaped invert 4 is formed on the inner bottom surface 2 a of the bottom wall 2.
And a socket portion 5 communicating with the invert 4 and connected to a pipe such as a fume pipe or a vinyl chloride pipe. 3a is an inner side surface of the side wall 3, 3b is a side wall 3
Is the open end face of the.

The invert 4 is, as shown in FIG.
It is formed in various shapes depending on the number and direction of the tubes connected to the bottom block 1. For example, a straight type that communicates with one outlet (a), a straight type that communicates with one outlet and terminates at the center (b), and a straight type that communicates with two outlets ( c) Elbow-like one communicating with two outlets (d) (e) Branching one communicating with four outlets (f) Branching one communicating with three outlets (g)
There are various modes such as (h) and (i). Further, the elbow shape and the branched shape have various angles θ depending on the difference in the approach angle of the pipe. For example, a large number of three-way branch type (g), such as 290 types, and four-way branch type (f), for example, 480 types, with different angles are prepared.

The bottom block 1 of such a manhole is molded by pouring concrete into a mold. The socket 5 is formed by post processing. And, in the past, this manhole bottom block forming die was made of metal and manufactured in accordance with the shape of each invert 4.

[0005]

By the way, in the conventional manhole bottom block forming die, since it is manufactured to match the shape of the invert 4 one by one using the metal, as described above, the invert 4 is manufactured. If there are a large number of types, it is necessary to prepare the same number of molding dies, and since metal is used, the number of manufacturing steps increases, extra manufacturing time is required, and the cost becomes high. There was a problem.

The present invention has been made in view of the above problems, and makes it possible to mold many kinds of manhole bottom blocks having different invert shapes with a single mold, and to facilitate the manufacture of the mold. In addition to improving the manufacturing efficiency by making it possible to immediately respond to the difference in the type of invert,
An object of the present invention is to provide a method for manufacturing a manhole bottom block forming die and a manhole bottom block forming die, which are intended to reduce the number of manufacturing steps, the manufacturing time, and the cost.

[0007]

Means for Solving the Problems The technical means of the present invention for solving such a problem is to provide a method for producing a mold for molding a bottom block of a manhole having a groove-shaped invert on the inner bottom surface. , Forming an invert molding portion for molding an invert on the bottom molding surface for molding the inner bottom surface of the bottom block, and forming a non-breathable film on the bottom molding surface forming the invert molding portion, Air is drawn between the film and the bottom molding surface, and the molding die is configured in a state where the film is pressed against the invert molding portion.

Further, in a manhole bottom block forming die for forming a bottom block of a manhole having groove-like inverts on the inner bottom surface thereof, a bottom surface forming surface formed of an air-permeable member for forming an inner bottom surface of the bottom block is provided. An inner mold, an invert molding part formed by laying sand on the bottom molding surface of the inner mold to mold an invert, and a non-air-permeable film coated on the bottom molding surface of the inner mold forming this invert molding part. , A vacuum device for sucking air between the film and the bottom molding surface of the inner mold through the inner mold.

[0009]

According to this means, the invert molding portion for molding the invert is formed by sanding on the bottom molding surface for molding the inner bottom surface of the bottom lump, and the bottom molding surface on which the invert molding portion is formed is not formed. A mold is manufactured by coating a breathable film and sucking air between the film and the bottom molding surface. In this case, it suffices to pour sand to form an invert shape, and since the sand is easily deformed, the invert molding portion can be formed extremely easily in a short time. Further, since the invert molding portion is pressed down by the film, the sand of the inverter molding portion becomes hard, and the strength substantially similar to that of metal is obtained, which does not hinder the molding.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a manhole bottom block forming die and a manhole bottom block forming die according to an embodiment of the present invention will now be described in detail with reference to the accompanying drawings. A method for manufacturing the manhole bottom block molding die according to the embodiment will be described in the description of the manhole bottom block molding die according to the embodiment manufactured by the manufacturing method. The same components as those described above will be designated by the same reference numerals.

FIGS. 1 to 3 show a mandrel bottom block forming die according to an embodiment of the present invention. This mold is for molding the manhole bottom block 1 having the groove-like invert 4 having a semicircular cross section on the inner bottom surface 2a, as in the above.

In the embodiment, reference numeral 10 denotes an inner mold, which is formed of a breathable member such as porous ceramics, for molding the inner bottom surface 2a of the bottom wall 2 of the bottom block 1 of the manhole. 11 and a cylindrical portion 13 having a side surface molding surface 12 for molding the inner side surface 3a of the side wall 3, and an opening end surface 3b of the side wall 3 of the bottom block 1 of the manhole formed on the lower peripheral edge of the cylindrical portion 13 And a flange portion 15 having an end surface molding surface 14 for forming the end surface. This inner mold 1
0 is supported by a base member 17 having a cavity 16 that contacts the inner mold 10.

Reference numeral 18 denotes an invert molding section, which is an inner mold 1.
The bottom molding surface 11 of No. 0 is formed by filling sand. The shape of the invert molding portion 18 can be freely changed by using, for example, a dedicated spatula, a trowel, or a wooden mold that is easy to manufacture, and is adapted to various shapes of the invert 4 described above. Formed.

Reference numeral 20 denotes a film, which is made of, for example, an air-impermeable sheet such as rubber or vinyl chloride, and has a bottom molding surface 1 of the inner mold 10 in which the invert molding portion 18 is formed.
1, the side surface molding surface 12 and the end surface molding surface 14 are covered.

Reference numeral 21 denotes a vacuum device, which sucks air in the space 16 of the base member 17 to draw air between the film 20 and the bottom molding surface 11, side molding surface 12 and end molding surface 14 of the inner mold 10. Is sucked through the inner mold 10, and the invert molding portion 18 is pressed by the film 20.

Reference numeral 22 denotes an outer side surface 3c of the bottom block 1 of the manhole.
Is an outer mold for molding, and is moved to a molding position where it is divided into two parts and joined to each other to enable molding of the bottom block 1 and a separation position where it is separated from each other to facilitate removal of the bottom block 1. To be

Next, the manufacturing process of the mandrel bottom block forming die according to the embodiment will be described with reference to FIG. Now, for example,
As shown in FIG. 8C, the case where the forming die for forming the bottom block 1 in which the shape of the invert 4 communicates with the two outlets and has a straight shape is manufactured will be described. Figure 4 (a)
As shown in (b), first, the bottom surface molding surface 11 of the inner mold 10 is formed.
Sand is laid on it, and the shape is adjusted to a straight shape with a semicircular cross section by using, for example, a special spatula, a trowel, or a wooden mold that is easy to manufacture, and the invert molding portion 18 is formed. In this case, since it is only necessary to pour sand to form the shape of the invert 4, it is possible to form the invert forming portion 18 extremely easily and in a short time, as compared with the conventional case where the metal is manufactured one by one.

Then, as shown in FIG. 4 (c), the inner mold 10 having the invert molding portion 18 is covered with a non-breathable film 20, and the vacuum device 21 is driven to leave a space in the base member 17. Air between the film 20 and the inner mold 10 is sucked through 16 and the inner mold 10 to make a substantially vacuum state. As a result, the invert molding portion 18 is pressed by the film 20, and a required molding die is manufactured. still,
The vacuum device 21 may be driven just before pouring the fluidized concrete. In this case, since the invert molding portion 18 is pressed by the film 20, the sand of the inversion molding portion 18 becomes hard and has substantially the same strength as metal.

Next, a case where the bottom block 1 of the manhole is molded by using the molding die manufactured as described above will be described. As shown in FIG. 5A, with the outer die 22 joined to the molding position and the vacuum device 21 is driven,
Pour liquid concrete. Then, the upper surface is flattened with a trowel or the like, and then cured for a required time. in this case,
A desired bottom block 1 is formed by the inner mold 10 and the outer mold 22. In particular, the bottom molding surface 11 molds the general surface of the bottom surface, and the inverting molding part 18 calibrates the inversion 4
However, since the invert molding portion 18 is pressed down by the film 20 and has a hardness similar to that of metal, the invert molding portion 18 will not be deformed by concrete, and the invert 4 will be surely molded into a required shape. .
It should be noted that during the curing, even if the driving of the vacuum device 21 is stopped, the situation that the invert molding portion 18 is deformed by the weight of the concrete does not occur, but it is desirable to drive the concrete until the concrete becomes stable.

At the time of taking out the product, the outer mold 22 is separated to the demolding position, and the product is lifted by a crane or the like and demolded. Thereby, as shown in FIG. 5B, the product in which the invert 4 is molded is taken out. After that, FIG. 5 (c)
As shown in FIG. 3, the socket portion 5 is formed by post-processing to obtain a finished manhole bottom block 1.

Also, when manufacturing the bottom block 1 having the inverts 4 having a shape other than the straight inverts 4 as shown in FIG. 8, sand is made in accordance with the shape of the inverts 4 in the same manner as described above. It is sufficient to form the inversion molding portion 18, cover the film 20 and suck the film to manufacture a molding die, and any shape of the inversion 4 can be easily dealt with.

In the manufacturing apparatus according to the above embodiment, the inner mold 10 is entirely made of a breathable member, but the invention is not limited to this, and the portion for molding the inner bottom surface 2a is made of a breathable member. May be formed so that suction is performed only from the inner bottom surface 2a portion, and it may be appropriately changed. Further, in the manufacturing method according to the above embodiment,
The inner mold 10 is formed of a breathable member, and the air between the film 20 and the inner mold 10 is sucked through the breathable member, but the invention is not necessarily limited to this, and the inner mold 10 is non-breathable. It may be formed of a member, and a suction nozzle may be inserted between the film 20 and the inner mold 10 to suck the air between them, which may be appropriately changed.

[0023]

As described above, according to the method for manufacturing the manhole bottom block forming die and the manhole bottom block forming die of the present invention, since the invert forming portion is formed by laminating sand, the sand is not formed. Since the deformation can be freely performed, it is possible to form the forming die very easily and in a short time, as compared with the conventional case where the metal is manufactured one by one. Further, since the forming die is configured in a state where the inversion forming portion is pressed by the film, the strength of the inverter forming portion can be secured, and the forming can be performed similarly to the case of the metal die. Therefore, it becomes possible to mold many types of manhole bottom blocks having different invert shapes with one die, and moreover, the production of the die becomes easy, so that it is possible to immediately respond to the difference in invert type and improve the production efficiency. While being able to
The number of manufacturing steps and the manufacturing time can be shortened and the cost can be reduced, which is extremely useful for manufacturing the bottom block of the manhole.

[Brief description of drawings]

FIG. 1 is a perspective view showing a forming die for a bottom mass of a manhole according to an embodiment of the present invention.

FIG. 2 is a side cross-sectional view showing a mandrel bottom block forming die according to an embodiment of the present invention.

FIG. 3 is another side cross-sectional view showing the mandrel bottom block forming die according to the embodiment of the present invention.

FIG. 4 is a diagram showing a manufacturing process of a mold for bottom mass of manholes according to the example.

FIG. 5 is a process drawing when forming a bottom block of a manhole according to an example.

FIG. 6 is a partially cutaway perspective view showing an example of the configuration of a manhole.

FIG. 7 is a cross-sectional view showing an example of a bottom mass of a manhole.

FIG. 8 is a plan view showing types of inverts formed on a bottom block of a manhole.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bottom block 2 Bottom wall 2a Inner bottom surface 3 Side wall 3a Inner side surface 3b Opening end surface 4 Invert 10 Inner mold 11 Bottom molding surface 12 Side molding surface 14 End surface molding surface 18 Invert molding portion 20 Film 21 Vacuum device 22 Outer mold

Claims (2)

(57) [Claims] 1. A method for producing a forming die for forming a bottom block of a manhole having groove-shaped inverts on an inner bottom surface thereof, the method comprising the step of forming an invert on a bottom surface forming surface for forming an inner bottom surface of the bottom block. Part is filled with sand, the non-breathable film is covered on the bottom molding surface on which the invert molding portion is formed, air between this film and the bottom molding surface is sucked, and the inversion molding portion is formed by the film. A method of manufacturing a mandrel bottom block forming die, comprising forming the die in a pressed state. 2. A manhole bottom block molding die for molding a manhole bottom block having groove-like inverts on the inner bottom surface thereof, which is provided with a bottom surface molding surface formed of a breathable member for molding the inner bottom surface of the bottom block. An inner mold, an invert molding part formed by laying sand on the bottom molding surface of the inner mold to mold an invert, and a non-air-permeable film coated on the bottom molding surface of the inner mold forming this invert molding part. And a vacuum device for sucking air between the film and the bottom molding surface of the inner mold through the inner mold.