JPH0136573Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention is applicable to box culverts, PCs, etc.
This invention relates to an inner formwork used to form a hollow part of a concrete box-shaped product such as a box-shaped girder.

Taking a PC box girder as an example, when manufacturing it in a factory, etc., it is manufactured as blocks of appropriate dimensions that are divided into multiple pieces in the length direction of the girder, taking into consideration transportation to the civil engineering work site. Ru. These are then integrated on site and prestressed using prestressed steel to create a prestressed box-shaped girder.

By the way, since each of the blocks mentioned above is formed in a shape in which one end of the hollow part is opened at the end face of the block (the surface to be joined to the adjacent block), the cross-sectional area of the PC box-shaped girder is large, and the hollow part of each block is opened. When workers enter the inner mold for molding, the inner mold is constructed so that it can be disassembled so that it can be used repeatedly.

However, if the hollow part is narrow, it is extremely troublesome for a worker to enter the inner formwork and operate bolts, nuts, etc., and the work efficiency is poor. In addition, if the cross section of the block is small and the inner formwork is of such a size that a worker cannot enter it, or if it is extremely difficult to operate bolts, nuts, etc. even if a worker can get in, the inner formwork The current situation is that they are being buried to death.

Therefore, the present invention has been developed so that even in such cases, the inner formwork can be easily removed by external operation, improving work efficiency and ensuring economic efficiency by allowing repeated use. The present invention provides an inner formwork that has a simple structure and is easy to repair and handle.

In order to achieve this objective, the present invention uses a plurality of formwork units divided along the length direction of the hollow part of a concrete box-shaped product, and a distance between these formwork unit groups. a spacer that can be switched between a first state in which the spacing is held constant and a second state in which the maintenance of the spacing is released; a joint bar that is removably disposed at a joint on the outer peripheral surface of a group of formwork units; and a formwork unit. One end of the formwork unit group is removably attached to a partition plate attached to the outer formwork, and the other end is suspended horizontally on the outer formwork. It is characterized by being configured to be suspended and supported from the horizontal rods via vertically removable steel rods.

Hereinafter, an example in which the present invention is applied to the inner formwork of a PC box-shaped girder, which is an example of a concrete box-shaped product, will be described based on the drawings.

FIG. 1 is a schematic plan view showing a state in which a plurality of steel inner formworks A arranged in series in the girder length direction are assembled at predetermined positions of steel outer formwork B, and FIG. 2 is a schematic plan view showing the inner formwork A. FIG. 3 is a schematic side view of the outer formwork B. FIG.

The outer formwork B is constituted by a bottom plate 1 and left and right side plates 2 which are removably installed at both ends of the bottom plate 1 in the width direction, and is configured to be divisible into a plurality of pieces in the girder length direction. Reference numeral 3 indicates a horizontal rod for width stopping that is removably installed between the left and right side plates 2, and 4 indicates a steel partition plate that divides the internal space of the outer formwork B into a plurality of sections in the longitudinal direction of the girder. In the area divided by board 4,
A block of PC box girder is molded.

As shown in FIGS. 4 to 9, each inner formwork A is divided into a plurality of molds (four in this example) divided along the girder length direction (that is, in the longitudinal section). A first state in which the interval l between the frame units a ₁ , a ₂ , a ₃ , a ₄ and the _four groups of these frame units a ₁ , a ₂ , a ₃ , a is kept constant, and the interval l a spacer 5 that can be switched to a second state in which holding is released, and a plurality of spacers that are disposed at joints on the outer peripheral surfaces of the four groups of formwork units a ₁ , a ₂ , a ₃ , and a ₄ so as to be removable in the longitudinal direction. steel joint rods 6 (four in this embodiment) and a formwork unit.
A plurality of bands 7 are wound around the outer peripheral surfaces of the _{a 1} , a ₂ , a ₃ , and a ₄ groups to restrain the outward movement of each formwork unit.
It is equipped with As the band 7, steel bands or resin bands used for packaging various articles can be used as they are. And spacer 5
is in the first state, the joint bar 6 is inserted in a predetermined position, and the band 7 is wound, one end of the group of formwork units a ₁ , a ₂ , a ₃ , a ₄ is Partition plate 4
The other end is attached to the specified horizontal rod 3.
It is configured to be suspended and supported via a vertically removable steel rod 8.

Each formwork unit a ₁ , a ₂ , a ₃ , a ₄ has an annular shape when viewed from the longitudinal direction of the girder, including the outer periphery and end weir plates 9 and 9' forming the inner surface of the hollow part of the PC box-shaped girder block. It is composed of a flange 10, angle members 11 provided at right-angled corners of the flange 10, and the like. Further, the joints on the outer peripheral surfaces of the formwork units a ₁ , a ₂ , a ₃ , and a ₄ are closed by the joint bars 6 to prevent concrete from flowing in, but the joints on the outer peripheral surfaces of the formwork units a ₁ , a 2 , a ₂ , a ₃ , a ₄ groups, the cross-shaped joints formed on the end face opposite to the partition plate 4 are joint covers 12a, 12b, 12c.
This prevents concrete from flowing in. The joint cover 12a is welded to the end face plate 9' of the formwork unit _a1 , and the side edge of the joint cover 12a is
It overlaps the end face plate 9' of the formwork unit _a2 . The side edge of the joint cover 12b welded to the end shear plate 9' of the formwork unit _a3 overlaps the end shear plate 9 _' of the formwork unit _a2 , and The L-shaped joint cover 12c welded to the end weir plate 9' is
Formwork unit a ₁ whose side edges are located diagonally,
It overlaps with the end face plate 9' of _a3 . This improves the effect of preventing concrete from flowing in by overlapping the joint covers 12a, 12b, 12c and the end face plate 9', and also prevents the formwork units a ₁ , a ₂ , a ₃ , a ₄ from blocking the hollow parts. By pulling the joint covers 12a, 12b, and 12c out in a predetermined order from the opening, consideration is given to preventing the joint covers 12a, 12b, and 12c from becoming obstacles to the movement of the joints. Note that packing tape may be attached to each of the above-mentioned overlapping portions to further enhance the effect of preventing concrete from flowing.

The detailed configuration of the spacer 5 is as follows.

That is, as shown in FIGS. 4, 10, and 11, among the _four groups of formwork units a ₁ , a ₂ , a ₃ , a , two formwork units a located diagonally Crankshafts 14 parallel to the girder length direction are mounted inside each of the crankshafts 1 and _a3 via a plurality of bearing plates 13 _, and each crankshaft 14 has a plurality of pairs of crank plates 15 arranged at appropriate intervals. It is provided. Of these crank plates 15, two stopper arms 16a are pivotally supported on the crank plate 15 located adjacent to one side of the bearing plate 13 with the phases of pivot pins 17a being 180 degrees different. A guide roller 18a of each stopper arm 16a is pivotally supported on the bearing plate 13. Two stopper arms 16b are pivotally supported by one pivot pin 17b on the crank plate 15 located adjacent to the other side of the bearing plate 13.
A guide roller 18b of each stopper arm 16b is pivotally supported on the bearing plate 13. and,
The free ends of the stopper arms 16a, 16b are configured to move in and out of the two right-angled sides of the formwork units _a1 , _a3 by forward and reverse rotation of the crankshaft 14. On the other hand, the remaining two formwork units a ₂ ,
_A4 is provided with a seat 19 at a position facing the free ends of the stopper arms 16a, 16b. Further, one end of the crankshaft 14 protrudes from the end bearing plate 13, and this protruding portion is provided with a square shaft portion 14a for detachably attaching a handle (not shown) and a crank positioning plate 14b. It is being Through holes are formed at predetermined positions of the bearing plate 13 at the tip and end of the crank positioning plate 14b, respectively, and by inserting the pin 20 across these through holes, the crankshaft 14 can be moved to a predetermined position. It is configured so that it can be fixed at any rotation angle. 13a is a reinforcing plate.

Therefore, by attaching a handle (not shown) to the square shaft portion 14a and rotating the crankshaft 14 by approximately 90 degrees, the free ends of the stopper arms 16a, 16b can be moved away from the two sides of the formwork units _a1 , _a3 . It protrudes and comes into contact with the catch seat 19, resulting in the above-mentioned first state. In this first state, the crankshaft 14 is fixed with the pin 20. Then, by removing the pin 20 and reversing the crankshaft 14, the stopper arms 16a, 16b are attached to the formwork units _a1 ,
It is pulled in from the two sides of a ₃ and enters the second state described above.

In addition, in this embodiment, the stopper arm 1
6a is also used as a support member for the joint bar 6. That is, the stopper arm 16a is a formwork unit.
When it protrudes from the two sides a ₁ and a ₃ , it comes into contact with the back of the joint bar 6, and the joint bar 6 is damaged by the pressure of the concrete.
It is configured to prevent inward movement of the
This aims to simplify the structure by using multiple parts, and while reliably preventing the joint bar 6 from moving inward, it also allows for easy removal of the joint bar 6 when demolding. This was taken into consideration.

One end of the 4 group of formwork units a ₁ , a ₂ , a ₃ , _a and the partition plate 4
The mounting structure is as follows. In addition, partition plate 4
4 groups of formwork units a ₁ , a ₂ , a ₃ , and a located on one side of the partition plate ₄ and formwork units located on the ground side of the partition plate 4
Since the a ₁ , a ₂ , a ₃ , and a ₄ groups have different attachment structures to the partition plate 4, they will be explained in order.

In FIG. 1, each partition plate 4 and a formwork unit of an inner formwork A having one end adjacent to the left side of each partition plate 4.
To attach the groups a ₁ , a _{2 ,} a ₃ , _{and a 4, as shown} in FIG. It is attached to a positioning plate 21 which is annular when viewed from the direction with pins and bolts and nuts, and this positioning plate 21 is attached to the partition plate 4 with bolts and nuts 22.

In FIG. 1, each partition plate 4 is attached to four groups of formwork units a ₁ , a ₂ , a ₃ , and a of the inner formwork A whose one end is adjacent to the right side of each partition plate ₄ . is carried out as follows. That is _, as _{shown in FIG} .
0 and the positioning plate 21 to which these flanges 10 are connected by pins, bolts, and nuts in the same way as in the above case, horizontal pin holes are formed at opposite positions, and each partition plate On the right side of 4,
A fastening pin 23 having a vertical wedge insertion hole 23a is provided in a protruding manner by plug welding or the like. Further, a rectangular cylindrical wedge guide 24 is welded to the back surface of the flange 10 located above the pin hole. Then, the flanges 10 at one end of the formwork units a ₁ , a ₂ , a ₃ , and a ₄ are connected to the positioning plate 21 , and after the fastening pins 23 are inserted into these pin holes, the wedges are inserted from above. 25 into the wedge insertion hole 23a of the fastening pin 23, and formwork unit a ₁ ,
A ₂ , a ₃ , and ₄ groups of a are attached to a partition plate 4.

The wedge 25 is formed to a length that projects from the concrete top of the PC box girder block to be formed, and is fitted with a sleeve (not shown) that fits over the portion of the wedge 25 that projects upward from the guide 24. 2) is buried in the concrete to prevent the protruding portion of the wedge 25 from adhering to the concrete. Further, in this embodiment, as shown in FIG. 15, a plurality of positioning protrusions 26 having slopes for guiding the inner peripheral edge of the positioning plate 21 protrude on both left and right sides of each partition plate 4. It is set up. This makes it easy to align the bolt and the bolt hole, and the fastening pin 23 and the pin hole, respectively, by the cam action (self-aligning action) of the slope of the positioning protrusion 26. 4a
4b is a wedge hole for detachably attaching the partition plate 4 to the outer formwork B, and 4b is a sheath tube insertion hole.

Formwork units a ₁ , a ₂ , a ₃ , a ₄ in each inner formwork A
The structure for suspending and supporting the other end of the group (the side opposite to the partition plate 4) is as follows.

That is, the lower formwork units a ₃ and a ₄ have a nut 27 welded to the inner lower part thereof, which is threadedly engaged with the threaded part formed at the lower end of the steel rod 8 mentioned above, A steel rod guide pipe 28 is fixedly provided by welding. Upper formwork unit a ₁ ,
A ₂ is provided with a steel rod guide pipe 29 that is concentric with the pipe 28, and a hole is provided in the part of the weir plate 9 corresponding to the opening at the upper end, and a hole is provided in this hole with a diameter decreasing toward the lower end. The tapered sleeve 30 is configured so that it can be inserted and removed freely.

Therefore, the steel rod 8 is passed through the steel rod guide pipes 29 and 28 from above the sleeve 30 and screwed onto the nut 27, and the upper end of the steel rod 8 is inserted into the horizontal rod 3 described above. , the steel rod 8 is tightened and fixed to the horizontal rod 3 by a pair of upper and lower nuts 31, 31 which are screwed into the threaded part on the upper end side, and another nut 32 which is screwed into the threaded part is brought into contact with the upper end surface of the sleeve 30. By bringing them into contact with each other, the _four groups of formwork units a ₁ , a ₂ , a ₃ , and a can be suspended and supported in a state where they are prevented from rising due to the buoyancy of the concrete.

Next, the procedure for assembling and demolding the inner formwork A will be explained.

First, the formwork unit _A3 is placed on a stand (not shown), and the spacer 5 is placed in the first state, that is, the stopper arms 16a and 16b are made to protrude, and the joint bars on the bottom and one side are set. 6 in place.

Next, the formwork unit A4 is set side by side with the formwork unit _A3 , and the joint bar 6 on _the other side (formwork unit _A4 side) is set.

Next, formwork unit a1 is placed on formwork unit _a4 , formwork unit _a2 is placed on formwork unit _a3 , and the formwork unit _a1 is placed on top of formwork unit _a1 . Put the spacer 5 in the first state, and set the joint bar 6 on the upper surface side.

Thereafter, a positioning plate 21 is attached to one end of the _four group of formwork units a ₁ , a ₂ , a ₃ , and a.

Next, the band 7 is wound around the outer peripheral surfaces of the _four groups of formwork units a ₁ , a ₂ , a ₃ , and a.

The inner formwork A assembled through the above steps is carried to the outer formwork B, one end of the inner formwork A is attached to the partition plate 4, and the other end is attached to the horizontal rod 3 on which the outer formwork B is constructed.
It is suspended and supported via a steel rod 8.

After curing and hardening of the block concrete, when removing the mold, release the width restraints by the horizontal rods 3, fold down the left and right side plates 2 of the outer formwork B, pull out the wedges 25 upwards, and remove the ends of the blocks. The block is separated from the other blocks along with the partition plate 4 (that is, in FIG. 1, it is separated between the right side of the left end partition plate 4 and the inner formwork A connected thereto).

After removing the partition plate 4 of the separated block and the positioning plate 21 attached to it,
The crankshaft 14 is rotated to switch the spacer 5 to the second state and remove the joint bar 6. As a result, the formwork units a ₁ , a ₂ , a ₃ , a ₄
can be moved inwardly within the mutual spacing, allowing the block to break free of its adhesion to the concrete.

Therefore, the formwork units a ₁ , a ₂ , a ₃ , and a ₄ can be extracted from the hollow portion of the block in a predetermined order.

Note that only the band 7 is left on the inner surface of the hollow part of the block and is disposable.

In the above embodiment, the spacer 5 was composed of the crankshaft 14, the crank plate 15, and the stopper arms 16a, 16b.
If you are targeting a PC box girder block,
As shown in FIG. 16, the spacer 5 can also be composed of a plurality of steel rods that are removably inserted into the gaps between the formwork units a ₁ , a ₂ , a ₃ , and a ₄ . be.

17 to 20 show another embodiment, which is characterized in that the spacer 5 is configured as follows.

That is, among the _four groups of formwork units a ₁ , a ₂ , a ₃ , and a , two formwork units a ₁ and a ₃ located diagonally have insides parallel to the girder length direction, respectively. three shafts 32
a, 32b, 32c are constructed so as to be slidable only in their axial direction, and each shaft 32a, 32b, 3
2c, pins 33 perpendicular to the shaft axis are pivotally mounted at appropriate intervals, and stopper arms 34 are swingable around the pins 33. On the other hand, each of the brackets 35 provided inside the formwork units a ₁ and a ₃ pivotally supports a pair of guide rollers 36 for regulating the moving direction of the stopper arm 34 . be. And shafts 32a, 32b,
By sliding the stopper arms 32c toward one end in the axial direction, the free ends of the stopper arms 34 protrude from the two sides of the formwork units a ₁ and a ₃ and come into contact with the seats 19 . When the shafts 32a, 32b, 32c are slid in the opposite direction, the free ends of the stopper arms 34 are drawn into the formwork units _a1 , _a3 . The configuration is such that the device enters the second state described above. 3
4a... is a stopper arm attachment part.

In addition, a stopper arm 34 is attached to the central shaft 32a by pins 33 that are perpendicular to each other.
... are pivoted in two directions, and the outer shaft 32b,
32c is provided with a stopper arm 34 only in the vertical or horizontal direction. Stopper arms 34 on the shafts 32b, 32c also serve as members for preventing the joint bars 6 from moving inward.

The present invention has the above-mentioned configuration, in which inward movement of the formwork unit group is prevented by a spacer in the first state, and outward movement is prevented by a band wound around the outer peripheral surface of the formwork unit group. The hollow part of a concrete box-shaped product can be formed while the movement of the entire formwork unit group due to the buoyancy of concrete is prevented by the partition plates and steel rods, and when demolding, the partition plate By removing the steel rods, switching the spacer to the second state, and removing the joint bar, the adhesion between each formwork unit and the concrete is removed, and each formwork unit is separated into concrete box-shaped products one by one. It can be easily extracted from the hollow part.

Therefore, there is no need for workers to enter the inner formwork and perform inefficient work such as operating bolts and nuts, and even if the dimensions are such that workers cannot enter, Assembling and demolding can be easily performed by the following operations, so that nothing other than the band is buried, and it is possible to improve work efficiency and ensure economic efficiency by repeatedly using the inner mold.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a schematic plan view, Fig. 2 is a schematic side view of the inner formwork, Fig. 3 is a schematic side view of the outer formwork, and Fig. 4 is a concrete pouring state. 5 is a partially cutaway plan view of the inner formwork, FIG. 6 is a side view of the same, FIG. 7 is a front view of the same, FIG. 8 is a longitudinal sectional front view of the same, and FIG. It is a back view same as the above. Fig. 10 is a front view of the main part, Fig. 11 is a sectional view taken along the line A-A in Fig. 10, Fig. 12 is a longitudinal sectional side view of the main part, and Fig. 13 is the partition plate and the formwork unit on one side thereof. Cross-sectional view showing the mounting structure with the body, 1st
Figure 4 is a partially cutaway vertical side view showing the attachment structure between the partition plate and the formwork unit on the other side, Figure 15 is a front view of the partition plate, and Figure 16 is a diagram of the inner formwork showing another embodiment. 17 to 20 show another embodiment, and FIG. 17 is a longitudinal sectional front view, and FIG. 18 is a schematic longitudinal sectional front view.
The figure is a front view of the main part, FIG. 19 is a plan view of the main part, and FIG. 20 is a side view of the main part. A...Inner formwork, B...Outer formwork, 3...Horizontal rod, 4
... Partition plate, 5 ... Spacer, 6 ... Joint bar,
7... Band, 8... Steel rod, 14... Crankshaft, 15... Crank plate, 16a, 16b...
...Stopper arm, 32a, 32b, 32c...
...shaft, 34...stopper arm.

Claims (1)

[Scope of Claim for Utility Model Registration] An inner formwork for forming a hollow part of a concrete box-shaped product, comprising a plurality of formwork units divided along the length direction of the hollow part, and these molds. A spacer that can be switched between a first state in which the distance between the frame unit groups is maintained constant and a second state in which the maintenance of the distance is released, and a spacer that is removably disposed at a joint on the outer peripheral surface of the formwork unit group. It is equipped with a joint bar and a band wound around the outer circumferential surface of the formwork unit group, and one end of the formwork unit group is removably attached to a partition plate attached to the outer formwork, and the other end is attached to the outside of the formwork unit group. An inner formwork for producing a concrete box shape, characterized in that it is configured to be suspended and supported by horizontal rods that are suspended horizontally on the formwork via vertically removable steel rods. The inner formwork according to claim 1, wherein the number of formwork units is four. A crankshaft in which the spacer is pivoted inside a formwork unit located in an opposing direction, a plurality of crank plates provided on the crankshaft, and a pair of stopper arms pivotally supported on each crank plate. The inner formwork according to claim 1 of the utility model registration claim, characterized in that it is constituted by: The inner formwork according to claim 1, wherein the stopper arm is also used as a support member for the joint bar. The inner formwork according to claim 1 or 2, wherein the spacer is composed of a plurality of removable steel rods.