JPS6356405A - Formwork for centrifugal casting of concrete - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a formwork for centrifugal casting of concrete products (for example, concrete piles, humid pipes, utility poles, etc.) By making one of the members have a high arc cross section and use it as the formwork body, and the other side having a low arc and use it as a lid, the capacity of the formwork body is increased, and when the concrete is filled with unhardened concrete, the concrete is used as the formwork body. To prevent the fine aggregate of the concrete from being caught between two members constituting the formwork when closing the formwork by preventing it from adhering to the edge of the main body.

[Conventional technology]

As a conventional formwork for centrifugal casting of concrete, there is, for example, a formwork described in Japanese Utility Model Application Publication No. 60-94911. This formwork is configured to form a cylindrical shape, with an upper mold having a semicircular cross section and a lower mold having the same shape facing each other. Further, reinforcing members made of angle materials are fixed to the outsides of the joint portions of the upper and lower molds, respectively, and the upper and lower molds are integrated by tightening the opposing reinforcing members.

[Problem that the invention seeks to solve]

However, in the conventional formwork, as shown in Fig. 5, when a predetermined amount of unhardened concrete (a) is supplied into the lower frame (b), the amount of concrete (b) that has not hardened yet is smaller than the amount supplied. Due to its small capacity, the concrete (a) is placed in the lower frame (b).
It will rise higher than the edge (C). Then, the unhardened concrete (a) also collapsed on top of the green (C) of the lower frame cb>, and when the upper frame (d) was covered, the concrete (a) fell between both the upper and lower frames (b) (di) In addition, since cage-shaped reinforcing bars with a circular cross section (not shown) are placed inside the bottom frame (tll), the concrete (a) being poured hits the reinforcing bars and breaks into the bottom frame (tll).
When it spills outside the bl, some of it falls off the bottom frame (the edge of the bl).
C) adhesion is also a cause of the above-mentioned clogging.

In order to prevent this biting, even if the fine aggregate at the edge (C1) is removed by hand, such as by brushing it off,
Since the concrete (a) was raised, it collapsed again, and when personnel were assigned to remove it, the above-mentioned encroachment ended up happening, and both frames (1))
Each edge fc) (II) of d) is deformed and a gap is created here.If this gap exceeds a specified value, there is a problem in that concrete leaks due to the centrifugal force during centrifugal casting. However, there is a problem in that this leads to a deterioration in the quality of concrete products.

The invention described in the above-mentioned publication uses a rubber-like seal to prevent leakage of concrete due to the formation of the gap, but the seal also deteriorates due to adhesion and clogging of concrete, and eventually this This also causes concrete leakage, and there is a problem in that it cannot be decisively effective in preventing concrete leakage due to deformation between the upper and lower frames.

This invention dispels the conventional fixed concept that the upper frame and lower frame each have a semicircular shape, and focuses on the fact that if the overall cross section is circular, the function as a formwork for centrifugal casting can be fully demonstrated. The purpose is to prevent the fine aggregate of supplied concrete that has not yet hardened from getting caught in the opening and closing parts of the formwork.

[Means for solving problems]

A formwork for centrifugal casting of concrete according to the present invention includes a formwork body having a high arc cross section and a lid having a low arc cross section,
The mold body and the lid that covers the opening of the mold form a cylindrical shape.

[Effect]

The main body of the formwork has an arcuate cross section, with its opening facing upward, cage-shaped reinforcing bars are inserted into it, and it is then filled with unhardened concrete. If the size of the cage-like reinforcing bars is larger than the opening of the form body and cannot be inserted from there, the reinforcing bars are inserted from the axial end of the form body. In this case, the wire lobes suspending the cage reinforcing bars may be moved in the axial direction using the openings in the form body.

Further, after both axial ends of the form body are closed with end caps, concrete is filled from the opening located at the upper side at this point over the longitudinal direction of the form body. The formwork body has a large capacity due to its curved cross section, and the edge is also located high, so even if the amount of concrete reaches a predetermined value, concrete will not overflow to the edge of the formwork body. do not have. For this reason, the concrete once supplied inside the mold does not adhere to the edges of the form body, and if there is any concrete that adheres, it is only that which adheres during the filling process.

Therefore, if you are careful when filling with concrete or allow the tip of the concrete supply device to face the inside of the form body, concrete will not adhere to the edges, and even if it does, the amount will be extremely small. Moreover, if this is removed by brushing off or the like after filling with concrete, it will not stick again. Therefore, even if the opening of the formwork body is covered, the fine aggregate will not be trapped, so there will be no deformation of the area, resulting in leakage of concrete during centrifugal casting or deterioration of the quality of products based on this. .

After centrifugal casting and curing, the product is removed from the mold by extrusion.

That is, the form body is slightly deformed by opening the lid of the form body (depending on the opening/closing mechanism of H, the lid may remain closed) and expanding the opening of the form body using a jack or other means. The state is as follows. Since this is to separate the product from the formwork body, the deformation of the formwork body may be of a small size that allows the formwork body to recover elastically. Further, if the extrusion force for extruding the product allows the peeling to be performed smoothly, the deformation is not necessary.

Instead of extrusion, demolding may be performed by tension.

〔Example〕

1 to 4 show an embodiment of the present invention.

This formwork consists of a formwork main body l having an arcuate cross section, and a formwork main body 1.
The mold body 1 and the lid 2 form a cylindrical shape.

Therefore, the form body 1 and the lid 2 may be formed by vertically splitting one steel pipe.

The structure of M2 and its relationship with the form body 1 need only be such that the opening of the form body 1 can be opened and closed, and that it can withstand the centrifugal force during centrifugal casting when it is closed. Now, one of the reinforcing members 2a and 2b fixed to the edge of the lid 2 is pivoted to the block 1a fixed to the formwork body 1 with a pin 3, and the lid 2 is rotated around the pin 3. It is designed to open and close by turning.

Further, a locking mechanism 4 of M2 is formed in the reinforcing material 2b of the lid 2 and the reinforcing material 1b fixed to the edge of the opening of the form body 1. In order to save labor, it is desirable to use a locking mechanism 4 that automatically locks the lid 2 when the lid is closed and allows the lid 2 to be opened only when a separate operation is performed. If the minimum function is to prevent the lid 2 from opening during centrifugal casting, for example, if two members such as bolts, pins, or wedges that pass through the reinforcing members 1b and 2b are connected for a predetermined period of time, It is also possible to employ known fixing means.

In this embodiment, a reinforcing member 6 is fixed to the center of the lid 20 in the width direction, and a plurality of reinforcing members 7 are also fixed to the outer periphery of the form body 1. The reinforcing materials 1b, 2a, 2b described so far,
6.7 all extend in the longitudinal direction of the formwork, at least a part of which extends over the entire length of the formwork.

Further, the height dimensions of each of these reinforcing members are all the same, and the upper end of each reinforcing member touches a circle centered on the center of the formwork. This is because a ring 8, shown in dashed lines in FIG. 1 and in solid lines in FIG. 2, is attached to the outside of each of the reinforcements. Since the width dimension of this ring 80 is not very large, the height dimension of each reinforcing material is not subject to the above-mentioned restrictions if it is located away from the position where this ring 8 is installed in the axial direction of the formwork. . Further, the reinforcing material 1b,
2a, 2b.

6.7 each have a generally rectangular cross-section, but this cross-sectional shape may have any other shape.

The ring 8 has two arc-shaped semicircular parts 8a facing each other and is pivotally connected at one end by a pin 9.
A locking mechanism 10 is provided at the other end of a, and when the locking mechanism 10 is released, the two semicircular parts 8a are relatively rotatable, so that the ring 8 can be opened and closed. . Although a removable pin 10a is used here as the locking mechanism 10, other known means used for this type of attachment and detachment may also be used.

A plurality of such rings 8 are fitted around the formwork in the longitudinal direction of the formwork and are used to rotate the formwork. That is, as shown by the chain line in FIG. 1, the formwork on which the ring 8 is fitted is placed on two rolls 11 via one ring 8, and the formwork itself or the rolls 11 are rotated. A driving force is input so that the formwork rotates on the two rolls 11. All of the plurality of rings 8 are arranged on the roll ll as described above. The ring 8 is attached to the mold only during centrifugal casting by rotating the mold.

Reference numeral 12 shown in FIG. 3 denotes end covers of the formwork, which are arranged at both longitudinal ends of the formwork main body 1 to partition the inside and outside of the formwork.

An end of a steel rod 14 extending in the longitudinal direction of the arcuate reinforcing bars reinforcing the concrete product 13 is fixed to this @ lid 12, and this end 112 is fixed to the base plate 15 which is placed against the end surface of the form body 1. By pulling against the steel rod 14, a prestress is applied to the steel rod 14. Connect the end cover 12 to the substrate 1
Although a bolt/nut means 16 is shown for ease of explanation as a means for pulling on the tension member 5, any known means for applying prestress can be widely used. Typically there is a means of traction by means of jacks. Note that the material for each of the above parts was iron.

Next, a procedure for forming a concrete product using this example will be explained.

First, the formwork body 1 is placed in a state with its opening facing upward,
Also, leave the lid 2 open. In this state, arc-shaped reinforcing bars are inserted into the form body 1. This may be inserted from the end of the form body 1 as described above. At this time, the reinforcing bars can be inserted smoothly by manipulating the wire rope for suspending the reinforcing bars through the opening of the form body 1.

Thereafter, ends M12 are provided at both longitudinal ends of the form body 1, the ends of the steel rods 14 are fixed thereto, and the ends M12 are pulled against the substrate 15 to apply prestress to the steel rods 14.

This prestressing may be applied after the subsequent filling of unhardened concrete.

Then, the form body 1 is filled with unhardened concrete using the open M2 opening. Filling with concrete is performed from the opening over the longitudinal direction of the form body 1. The formwork main body l has a large capacity because its cross section forms an arc, and the edge of the opening is also located high, so even if the amount of concrete a reaches a predetermined value, as shown in Figure 4, The concrete a does not overflow to the edge of the form body 1. For this reason, the concrete a supplied to the inside does not adhere to the edges of the form body 1, and if there is any concrete that adheres, it is only that which adheres during the filling process.

Therefore, if you are careful when filling concrete a, or if you allow the tip of the concrete supply device to face the inside of the form body 1, concrete will not adhere to the edges, and even if it does, the amount will be extremely small. Become. Further, if the concrete a is removed by brushing off or the like after being filled, it will not stick again.Therefore, even if the lid 2 is placed over the opening of the form body l, fine aggregate will not be caught.

When filling with concrete is completed, the lid 2 is closed, the locking mechanism 4 locks between the formwork body 1 and M2, the ring 8 is fitted onto this, and the formwork is placed on roll ll. By rotating the concrete a, a centrifugal force is applied to the concrete a.

As mentioned above, the ring 8 is used, and the outer circumference of the ring 8 is the roll 11.
Since the formwork rotates smoothly when it rolls into contact with the roll 11, the outer ends of the reinforcing materials 6, 7, etc. may directly contact the roll 11 without using the ring 8. In this case, Since the outer periphery of the entire formwork has continuous unevenness in the direction of rotation, the formwork vibrates as it rotates, and the internal concrete is given centrifugal force and vibration, making it possible to obtain a concrete product with high density. .

When utilizing this vibration, if a rubber material, particularly a pneumatic tire, is used as the roll 11, noise caused by the vibration can be suppressed as much as possible.

In addition, when setting the vibration frequency and amplitude, etc., various conditions such as the number, spacing, and shape of irregularities of the reinforcing material 6, 7, etc. in the circumferential direction, the diameter of the roll 11, the rotation speed of the formwork, etc. are selected. shall be.

At this time, when changing the number, shape, etc. of the reinforcing members 6° 7 in order to set the vibration frequency and amplitude, it is sufficient to change only the position where the roll 11 contacts in accordance with the vibration conditions.

In other positions that are not in contact with the roll 11, it is only necessary to provide reinforcement necessary to maintain the strength of the formwork itself.

After the predetermined rotation is completed, if the ring 8 is used, it is removed and attached to the mold to be rotated next, or if the ring 8 is not used, it is directly subjected to the curing process. As described above, according to this embodiment, since the ring 8 is made removable, there is no need to provide the ring 8 on all formworks.
, because it only needs to be attached to the formwork in this process when the formwork is rotated, this reduces the cost of formwork in factories with a large number of formworks, and also reduces the external shape of the formwork. It also becomes smaller. This miniaturization allows a larger number of molds to be accommodated in a curing tank with the same volume than before, resulting in an improvement in product production capacity.

After curing and curing, the product 13 is taken out from the mold. This demolding pushes out the product 13 in the axial direction of the formwork, which is
This is done after releasing the means 16, removing the base plate 15, and removing the end cap 12 from the steel rod 14.

Then, by widening the opening of the form body 1 using a jack or the like, the form body 1 is slightly deformed in the direction of opening, and the extrusion is performed.

At this time, if the product 13 can be removed from the mold without expanding the opening of the formwork body 1 due to the fact that it is tapered like a telephone pole, for example, the expanding step is not necessary.
As the product 13 and the formwork are separated by spreading,
Expanding it will make demolding easier. When expanding this formwork body 1, each reinforcing member 1b, 2a, 2b, 6.7 extends only in the axial direction of the formwork, and members continuous in the circumferential direction are Since it does not exist, only the arc-shaped formwork body 1 acts as a resistance force for expanding the formwork body l.

Therefore, the work of expanding the form body 1 becomes easy. Note that the deformation of the formwork main body 1 at this time is within a range that the formwork main body 1 can be restored by its own elasticity.

When the demolding of the product 13 is completed, the production of concrete products using the formwork is completed, and the demolded product 13 is subjected to post-processing to become the final product, and the formwork after demolding is used for the next molding. used for.

The cross-sectional shape of the formwork body 1, which is a strong arc, has a central angle of about 315 degrees, and the cross-sectional shape of the lid 2, which is a weak arc, has a center angle of about 45 degrees. The lid is not necessarily limited to the angle mentioned above. The angle should be determined in accordance with various conditions such as the amount of unhardened concrete to be used and the inner diameter of the formwork. Furthermore, although the opening/closing structure of the lid 2 relative to the form body 1 is configured such that the lid 2 pivots in the above embodiment, any opening/closing means may be used in the present invention. For example, formwork body 1
Of course, M2 may be opened and closed by being attached to and removed from the mold body 1, or M2 may be opened and closed by sliding with respect to the form body 1.

〔Effect of the invention〕

As explained above, according to the present invention, since the formwork body has a well-arc cross section, the capacity is larger and the edge position is also larger than that of a conventional formwork with the same diameter. Because of the high temperature, the concrete will not overflow to the edge of the formwork body even if concrete a reaches a predetermined value.For this reason, once the concrete is supplied inside, it will not adhere to the edge of the formwork body. If there is any concrete that sticks, it will only be the one that sticks during the filling process, so even if it does stick, the amount will be extremely small.Furthermore, if you remove it by brushing it off after filling with concrete, , it will not stick again.Therefore, the labor required to prevent the above-mentioned adhesion can be saved.

Therefore, even if the opening of the formwork body is covered, the fine aggregate will not be trapped, so there will be no deformation of the area, resulting in leakage of concrete during centrifugal casting or deterioration of the quality of products based on this. . Therefore, the life of the formwork is extended, and green concrete products of stable quality can be produced at all times.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing one embodiment of the formwork according to the present invention, Fig. 2 is a front view of the ring shown in Fig. 1, and Fig. 3 is a state in which concrete is formed using the formwork shown in Fig. 1. Longitudinal sectional view, 4th
The figure is an explanatory view showing how concrete is filled, and FIG. 5 is an explanatory view showing how concrete is filled in a conventional example. 1... Form body, 2... Lid, lb, 2a. 2b, 6.7... Reinforcement material, 4... Lock mechanism, 8.
...Ring, 13...Concrete product, 14...
steel rod.

Claims (1)

[Claims] A formwork for centrifugal casting of concrete, comprising a formwork body having a greater arc in cross section and a lid having a less arc in cross section, the formwork body and the lid forming a cylindrical shape.