JPH0341326B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a formwork for manufacturing knotted concrete piles, which are mainly used as friction piles as foundation piles for structures, buildings, etc.

Conventionally, in the production of concrete piles used as foundation piles, a rotating mold is used in which a half-split right cylindrical forming form, a driving shaft and a driven shaft are arranged side by side, and rollers are arranged on each of the shafts. Using a centrifugal device, the formwork is placed on the rollers of the rotary centrifugal device, and the formwork is rotated by the rotational action of the rotary centrifugal device to generate centrifugal force on the concrete material filled in the formwork. This method forms a concrete pile that is integrated with a core material such as a rebar cage that has been pre-loaded.

However, if the concrete pile to be manufactured is a so-called knotted pile that has knots at the required intervals, it is necessary to provide knot forming parts in the formwork itself at the required intervals. If the mold is of a conventional form with a knot molded portion that bulges outward, when this is used in a rotary centrifugal device such as the one described above, the knot molded portion that has a bulged shape will be removed. Due to their presence, the balance during rotation tends to collapse, causing problems such as material separation and weakening of the pile body. In particular, formwork of the form described above is time-consuming and costly to manufacture, and when manufacturing PC piles, stress tends to concentrate at the bent portions of the bulged joint forming portions, resulting in poor strength. There were drawbacks such as the need for thick walls for retention.

In view of the above, the present invention has been made to provide a formwork for manufacturing knotted concrete piles that is easy to manufacture, inexpensive, suitable for maintaining strength, and capable of well-balanced and good rotary centrifugal forming. That is, the present invention consists of a half-split formwork that can be closed and fastened, and this half-split formwork has a corresponding half-circular shape inside the half-split mold of the half-split cylindrical formwork, and a joint. The halves of the inner mold forming the body molded part and the body molded part are fitted, the mating surfaces of both flanges are connected to each other on substantially the same plane, and the joint molded part is brought into contact with the inner surface of the half mold. It is characterized by being brought into contact and supported.

Next, embodiments of the present invention will be described based on the drawings.
1', 1' are a pair of half molds with a semicircular cross section that bisect the cylinder in the longitudinal direction, and the pair of half molds 1', 1' can be used to open and close the half cylinders. A formwork 1 is constructed. That is, engaging flanges 2, 2 are provided on the outside of each joining end of the half molds 1', 1', respectively, and are provided so as to be fastened at required locations with fasteners 3 such as bolts and nuts. .

Reference numeral 4 denotes an inner formwork that configures a joint molded portion 4a and a body molded portion 4b at required intervals in the longitudinal direction;
The cylindrical formwork 1 is divided into half-circular shapes corresponding to the above-mentioned cylindrical formwork 1, and the half bodies 4', 4' have their split surfaces inside the half-molds 1', 1' of the cylindrical formwork 1, respectively. The joint molded portions 4a are fitted into each half mold so that they are in contact with the inner surfaces of the half molds 1' and 1', and the mating surfaces formed by the flanges 2 and 5 of the two molds are connected to each other on substantially the same plane. They are connected by welding, fastening with bolts, or other means to form a half-split formwork that can rotate integrally.

The embodiments shown in FIGS. 1 to 3 show the case where the inner formwork 4 is connected to the cylindrical formwork 1 by welding means, and each joint end of the half bodies 4', 4' of the inner formwork 4 is connected to the inner formwork 4 by welding means. A flange serving as a mating surface is integrally provided on the outside of the part, and the flanges 5, 5 are welded to the inside of the joining end of the half molds 1', 1' of the cylindrical formwork 1. It is also possible to weld plates corresponding to the flanges 5, 5 to both the half bodies 4', 4' and the half molds 1', 1'.

4 and 5 show flanges 5, 5, which serve as mating surfaces, connected to halves 4', 4' of inner formwork 4, as an example of fastening by bolts, to the halves of cylindrical formwork 1. Counter-sunk screws 7, 7 are connected to the protrusions 6, 6 with female threads provided inside the joint ends of the split molds 1', 1'.
This shows the case where the agreement is concluded. The flanges 5, 5 may be formed separately from both the half bodies 4', 4' and the half molds 1', 1', and in this case, the flanges 5, 5 are formed separately from each other as shown in FIG. half body 4',
Protrusions 8, 8 and 6, 6 with female threads disposed on both the molds 1', 1' and the half molds 1', 1' face each other with countersunk screws 9, 9 and 7, respectively, in the same manner as above.
The agreement will be concluded at 7. When bolting is performed at the flanges 5, 5, the outer periphery of the joint molded portion 4a of the inner form 4 may be simply inscribed in the cylindrical form 1, but the joint molded portion 4a may be simply inscribed in the cylindrical form 1. Also, it is desirable to utilize the gap between the inner formwork 4 and the cylindrical formwork 1 to fasten them with bolts or the like.

For example, as shown in FIG.
Both ends of the outer circumferential surface portion 41 of a are made continuous or discontinuous in the circumferential direction and extend in the axial direction of the formwork, and the extending end portions 41' and 41' are bolted to the cylindrical formwork 1. Tighten 10 times. Further, when the inner diameter of the cylindrical formwork 1 is slightly larger than the outer diameter of the joint molded portion 4a of the inner mold 4 and there is a gap between the two, the outer peripheral surface 41 of the joint molded portion 4a has a protrusion corresponding to the distance. For example, it is sufficient to provide the space holding portion 11 as shown in FIGS. 8 and 9. In this case, it is also possible to fasten the space holding portion 11 to the cylindrical formwork 1 with bolts 10 as shown in the same figure. It is. The spacer 11 may be provided continuously in the circumferential direction, or may be provided discontinuously as shown in FIG. 10. It should be noted that it is also possible to maintain the inner formwork 4 in a fixed state in the cylindrical formwork 1 by simply fastening the joint molded portions 4a;
In terms of strength, it is preferable to use the above-mentioned flanges 5, 5 together with bolt fastening.

Further, in any of the embodiments, circumferential ribs 12 are provided on the outer periphery of the body molding portion 4b of the inner formwork 4 at required positions in the longitudinal direction of the formwork, and ribs in the longitudinal direction of the formwork are provided at required positions in the circumferential direction. 13 are preferably provided so as to be inscribed in the cylindrical formwork 1, respectively, so that the inner formwork 4 can be reinforced and thinned. When the ribs 12 and 13 are bolted 14 to the cylindrical formwork 1 as shown in FIG. 11, the inner formwork 4 becomes even stronger.

The inner formwork 4, that is, the half bodies 4', 4', is formed by forming joint forming portions 4a and body forming portions 4b alternately and continuously over the entire length. As shown in Fig. 12, each joint molded part 4a and each trunk molded part 4b are separately formed by press working, etc., and these parts are connected by welding, or each joint part molded part 4b is formed separately as shown in Fig. 13. Part molding part 4
The outer circumferential surface portion 41 of a and other portions are formed separately by press working or the like, and these portions are connected by welding. Further, it is also possible to separately form a plurality of pieces at the center of the outer circumferential surface portion 41 and then weld them. Further, each of the separately formed parts is not welded,
By attaching and fastening the inner formwork 4 to the cylindrical formwork 1, it is also possible to form a continuous inner formwork 4 over the entire length.

In the figure, 15 is a passive wheel that receives rotational power.
The outside of the cylindrical formwork 1 has a half-shape corresponding to the half-split molds 1', 1'.

The present invention has the above-mentioned configuration, and when forming a knotted concrete pile, two half-shaped formworks are prepared in advance, namely, the half-split molds 1' and 1' of the cylindrical formwork 1 and the inner formwork 4. Both halves 4' and 4' are opened and a core material such as a reinforcing bar cage is loaded inside, and a predetermined amount of ready-mixed concrete made by mixing cement, gravel, sand, water, etc. is filled. After that, the cylindrical formwork 1 and the inner formwork 4 are closed and fastened together.
In particular, the half body 4' of the inner formwork 4 is fitted into the inside of the half mold 1' of the outer half cylindrical formwork 1, and the mating surfaces formed by the flanges 5 and 2 of the two are connected to each other on substantially the same plane. Since it is integrally constructed as a half-split formwork, by closing and fastening the half-split molds 1' and 1' of the formwork 1,
The halves 4', 4' of the inner formwork 4 can also be closed. At the same time as the half-split formwork is closed, circular lids 16, 16 are fitted to both ends of the formwork. Then, the formwork A in this state is placed on a rotary centrifugal device so as to be supported by the passive wheel 15 as shown in FIGS. The knotted concrete pile 10 is manufactured by performing curing, demolding, etc. in the same manner as conventional methods.

After manufacturing, if the half molds 1', 1' of the form 1 are released and divided, the inner form 4 will be opened at the same time,
Concrete piles can be taken out without difficulty.

Therefore, the formwork A according to the present invention has a simple half-cylindrical formwork 1 having the same diameter over its entire length, and a corresponding half-circle shape, and has a joint forming part 4a and a body forming part 4b. Since the inner formwork 4 is combined with the inner formwork 4, it is sufficient to make the outer cylindrical formwork 1 thick and strong in terms of strength during centrifugal molding and transportation, and the inner formwork 4 does not interfere with molding. It is also possible to make the outer cylindrical form 1 so thin that there is no wall, and the weight of the outer cylindrical form 1 can be increased. In particular, the inner formwork 4 is built in such a way that the joint forming part 4a, where a large amount of concrete gathers during centrifugal forming and the centrifugal force due to rotational action becomes large, comes into contact with the outer cylindrical formwork 1. ,
The centrifugal force at this joint forming part 4a is
Even if the irregularly shaped inner mold is relatively thin, it can have sufficient strength. Moreover, since the joint molding portion 4a does not protrude outward, the stability during rotary centrifugal molding, that is, the rotational balance, is better than that of a mold having a joint molding portion that bulges outward. Coupled with the strength maintained by the cylindrical formwork 1, good centrifugal molding can be performed with less vibration and the like. In particular, the joint molding part 4 of the inner formwork
By supporting a in contact with the inner surface of the half-split cylindrical formwork 1, it is possible to prevent the knots from rotating in a piecewise manner during centrifugation, and also to directly transmit the slight vibrations of the outer formwork 1 to the joint-molded parts. 4a and the centrifugal force, it is possible to ensure good compaction of concrete at the joints. Therefore, it is possible to reliably fill the concrete material up to the ends of the joints, and there is no risk of material separation or deformation of the pile body, making it possible to manufacture strong jointed concrete piles.

Further, the formwork A of the present invention, which is a combination of the cylindrical formwork 1 and the inner formwork 4, has high compressive strength in the axial direction and is particularly suitable for manufacturing knotted concrete Pc piles. In other words, in a formwork with a cross-section of different diameters that has a joint forming part that bulges outward, Pc
When compressive stress is applied during tensioning of steel materials, buckling may occur due to stress concentration at the bends of the formwork.
In the case of the present invention, since the cylindrical formwork 1 having the same diameter over its entire length bears the compressive stress, there is no risk of buckling occurring.

Furthermore, in the case where the cylindrical formwork 1 and the inner formwork 4 are fastened together with bolts using the gap between the two formworks, as in the illustrated embodiment, assembly and disassembly are easy, and transportation, etc. It is convenient to handle, and especially when the inner formwork 4 is formed separately into a plurality of parts, the operation is easier and easier to manufacture, and the inner formwork 4 can be mass-produced by press processing as a single unit with a fixed shape. This has the advantage of reducing costs, and when the inner formwork 4 is worn and damaged, it is possible to replace only that part alone, which is economical. Also, for one cylindrical formwork 1, several types of inner formworks 4 with different diameters are used.
It can be incorporated and fixed according to the knotted concrete pile to be manufactured, and is lighter and more convenient than conventional formwork.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, and FIG. 1 is a plan view of one side with a half opening showing the case where a cylindrical form and an inner form are welded together, and FIG. A sectional view when the formwork is closed, Fig. 3 is an enlarged sectional view of a part of the previous figure, and Fig. 4 is a half-opened form showing an embodiment in which the cylindrical formwork and the inner formwork are fastened with bolts. One plan view, FIG. 5 is an enlarged cross-sectional view of a part of the formwork in a closed state taken along the line from the front figure, and FIG. 6 is a plan view of one half-opened side showing another embodiment.
Fig. 7 is a longitudinal sectional view showing an example of fastening at a joint forming part, and Figs. 8 and 9 are respectively showing examples of fastening at a joint forming part when the diameter of the cylindrical formwork increases. A vertical cross-sectional view of the section, FIG. 10 is a cross-sectional view of the same,
FIG. 11 is a partial sectional view when the ribs on the outer periphery of the body molding part are fastened to the cylindrical form; FIGS. 12 and 13 are schematic vertical sectional views showing examples of manufacturing the inner form, respectively; 14 and 15 are a plan view and a cross-sectional view showing the state during rotary centrifugal forming, and FIG. 16 is a perspective view of a knotted concrete pile to be manufactured. 1...Cylindrical formwork, 1', 1'...Half mold, 4...
...Inner formwork, 4a...Knob molded part, 4b...Body part molded part, 4', 4'...Half body, 5, 5...Flange, 41...Outer peripheral surface part.

Claims (1)

[Scope of Claims] 1. Consists of a half-split formwork that can be closed and fastened, and this half-split formwork has a half-split mold inside the half-split cylindrical formwork,
A corresponding half-circular shape is formed, and the half body of the inner mold forming the body molding part is fitted into the joint molding part, and the mating surfaces of both flanges are connected and formed on substantially the same plane, and the joint molding A formwork for manufacturing a knotted concrete pile, characterized in that a part is supported by abutting on the inner surface of a half-split mold. 2. Manufacture of a knotted concrete pile according to claim 1, in which the knot molded part and the body molded part are formed so as to correspond to each other when two half-split formworks are fastened with their mating surfaces facing each other. Formwork for. 3. A formwork for manufacturing a knotted concrete pile according to claim 1, wherein each half of the inner formwork is fixed to each half of a cylindrical formwork by welding means. 4. A formwork for manufacturing a knotted concrete pile according to claim 1, wherein each half of the inner formwork is fixed to each half of a cylindrical formwork by bolt fastening means. 5. Claim 1, wherein the inner mold is formed by separating into a plurality of parts at the molded part and connecting them by welding means, and by welding a flange to the semicircular edge. Formwork for manufacturing knotted concrete piles according to paragraph 2, paragraph 3, or paragraph 4.