JP7845938B2 - End formwork fixing device - Google Patents

Description

This invention relates to a formwork fixing device for lining concrete centering.

In the construction of the lining concrete for mountain tunnels, a semi-cylindrical, movable formwork called a "center" is used to pour concrete into the inner perimeter of the tunnel. During concrete pouring, wooden planks with a radius of approximately 20 cm, called "end formwork," are used as stopper formwork at the ends of the "centers" where the concrete joints are located. These are installed to seal the opening between the ground and the "center." Because the "end formwork" is installed and dismantled after each concrete pour using wooden sheet piles, through-beams, lumber, and pipe supports, it requires considerable time and effort.

The applicant proposes a structure for reducing the labor involved in the installation and dismantling of end formwork, in which a formwork fixing device, consisting of a continuous member made of square pipe and an end formwork fixing beam integrated into one unit, is installed on beam support steel members extending from the centering structure (see Patent Document 1).

Japanese Patent Publication No. 2022-45030

Patent Document 1 allows for easy installation and removal of the end formwork, as well as lowering, moving, and setting the centering mechanism, because the end formwork fixing beams and through members can remain in place. However, Patent Document 1 required simultaneous work involving setting the vertical position of the through members while supporting the through members and end formwork fixing beams, and the delicate work of adjusting the length of the end formwork fixing beams. While Patent Document 1 allowed for one-person operation, there was a need for further reduction of the burden on the worker.

The present invention aims to provide a formwork fixing device that can further reduce the burden of installing through members and formwork fixing beams to the formwork.

The end formwork fixing device of the present invention is an end formwork fixing device that supports the concrete pouring pressure by bringing a through member into contact with a plurality of end formworks arranged in parallel on the end face in the pouring space between the inner circumferential surface of the tunnel and the formwork of the centering, and comprises an end formwork fixing beam that supports the through member at the tip located on the side of the end face, and is rotatably installed on a beam support steel material that spans across the end face at a distance from the end face in a shape along the circumferential surface of the formwork so that the tip is movable in the direction normal to the circumferential surface of the formwork, and a biasing mechanism that biases the end formwork fixing beam upward so that the tip approaches the inner circumferential surface of the tunnel, wherein the end formwork fixing beam is equipped with an extension mechanism that adjusts the extension length that extends from the beam support steel material toward the end face.
Furthermore, in the end formwork fixing device of the present invention, the end formwork fixing beam may be rotatably installed on the beam support steel material such that its rear end protrudes from the beam support steel material in the direction opposite to the end face.
Furthermore, in the end formwork fixing device of the present invention, the biasing mechanism may pull the rear end of the end formwork fixing beam downward, away from the inner circumferential surface of the tunnel.
Furthermore, in the end formwork fixing device of the present invention, the end formwork fixing beam is installed on the beam support steel via a support that supports the pivot axis of the end formwork fixing beam, the support includes a column member extending downward from the beam support steel member, and the biasing mechanism may be interposed between the rear end of the end formwork fixing beam and the column member.
Furthermore, in the end formwork fixing device of the present invention, the through member is supported by being stretched across two or more end formwork fixing beams, the end formwork fixing beams are installed on the beam support steel via a support that supports the pivot axis of the end formwork fixing beams, and the support may be equipped with a tilt adjustment mechanism for adjusting the tilt of the pivot axis.

According to this invention, after the end formwork is installed, the through members can be easily installed to the end formwork simply by adjusting the extension length of the end formwork fixing beams. This significantly reduces the burden of installing the through members and end formwork fixing beams to the end formwork.

This figure shows the configuration of a centering structure with the gable formwork fixing device according to the present invention installed. Figure 1 shows the centering structure as viewed from the face side. This is a perspective view showing the configuration of the gable formwork fixing device according to the present invention. Figure 3 is a side view showing the configuration of the fixed beams of the gable formwork in a set state. Figure 3 is a perspective view showing the configuration of the gripping section. Figure 3 is a side view showing the configuration of the lumbar spine. Figure 3 is a perspective view showing the configuration of the support device. Figure 3 shows an example of how the support device is installed on the beam support steel material. Figure 3 is a side view showing the configuration of the retracted formwork fixing beams.

Next, embodiments for carrying out the present invention (hereinafter simply referred to as "embodiments") will be specifically described with reference to the drawings.

Referring to Figure 1, the end formwork fixing device 10 of this embodiment is installed on a centering structure 1 having an arch-shaped formwork 11 along the inner circumferential surface of the tunnel, which has been temporarily supported by concrete spraying or the like. It supports the end formwork that closes the end of the concrete lining space (hereinafter simply referred to as the concrete pouring space C) formed between the inner circumferential surface of the tunnel and the centering structure 1 (formwork 11).

The centering units 1 can travel on rails 2 laid along the tunnel axis (the direction of construction of the lining concrete). When the lining concrete is constructed from the tunnel entrance towards the tunnel face, multiple end formwork fixing devices 10 are installed on the tunnel face side of the centering unit 1, along the circumference of the formwork 11.

The formwork 11 is a steel member with a roughly semi-circular cross-section in the tunnel width direction, positioned to follow the inner circumferential surface of the tunnel. As shown in Figure 2, the formwork 11 is supported by a movable frame 13 via multiple jacks 12. The space between the formwork 11 and the inner circumferential surface of the tunnel becomes the pouring space C.

The mobile platform 13 is constructed of H-beams, channel steel, etc., and comprises multiple gate-shaped frames 14 arranged front and rear, and multiple vertical beam members (not shown) connecting the multiple gate-shaped frames 14. Wheels for running on rails 2 are provided at the lower ends of the gate-shaped frames 14. The internal cross-section of the gate-shaped frames 14 functions as a tunnel for transporting spoil and other materials.

The centering structure 1 (formwork 11) comprises a plurality of overhanging steel members 15 extending from the end face side toward the face at predetermined intervals along the perimeter of the formwork 11, and beam support steel members 16 fixed to the plurality of overhanging steel members 15. The beam support steel members 16 are shaped to conform to the perimeter of the formwork 11 and are spaced apart from the end face of the pouring space C. The end formwork fixing device 10 is installed on the beam support steel members 16.

Referring to Figures 3 and 4, the end formwork fixing device 10 is a device that supports the concrete pouring pressure by contacting multiple end formworks 3 arranged in parallel on the end face of the pouring space C. The end formwork fixing device 10 comprises three end formwork fixing beams 20, a through member 40, three support members 50, and a gas spring 70.

In Figure 4, reference numeral 17 indicates an angle member that spans the end face 11a of the formwork 11, extending inward from the face-side end, at a distance from the end face 11a. The angle member 17 functions as a fall prevention member to prevent the end formwork 3 from falling off, and also functions as a fixing member to secure the end formwork 3 by driving a camber 4 (wedge) between the angle member 17 and the end formwork 3.

The end formwork fixing beam 20 is a rod-shaped member equipped with an extension mechanism that adjusts the extension length extending from the beam support steel member 16 toward the end face of the pouring space C. In this embodiment, a pipe support, which is a temporary material, is used. The end formwork fixing beam 20 is installed so that its tip, located on the end face side of the pouring space C, is movable in the direction normal to the circumference of the formwork 11, and its middle section is rotatably installed on the beam support steel member 16. Hereinafter, the direction approaching the inner circumference of the tunnel will be referred to as the upward direction, and the direction away from the inner circumference of the tunnel will be referred to as the downward direction. The extension mechanism of the end formwork fixing beam 20 has no structural limitations as long as it can maintain a predetermined strength against a force compressing the axis when the length is adjusted. The extension mechanism of the end formwork fixing beam 20 can also use a cylinder that extends and retracts hydraulically or electrically.

The end formwork fixing beam 20 comprises a cylindrical (pipe-shaped) insertion tube 21 and a cylindrical waist tube 22. The rear end of the insertion tube 21 is inserted into the waist tube 22, and a gripping portion 30 is attached to its tip instead of a receiving plate.

The gripping section 30 is a gripping mechanism for gripping a through member 40, which is made of a hollow pipe with a circular cross-section, such as a single-pipe pipe. Referring to Figure 5, the gripping section 30 comprises a pipe receiving section 31 with a recess having approximately the same curvature as the outer circumference of the through member 40, and a movable section 32 with one end pivotally supported. The movable section 32 is rotated toward the pipe receiving section 31 by tightening the bolt 33, gripping the through member 40 between itself and the pipe receiving section 31.

The through member 40 is gripped by gripping parts 30 attached to the ends of the three end formwork fixing beams 20, and functions as a contact part that abuts against the multiple end formwork 3 arranged side by side on the end face of the pouring space C. The number of end formwork fixing beams 20 and the length of the through member 40 in the end formwork fixing device 10 can be appropriately set considering the concrete pouring pressure.

The waist pipe 22 has its base plate removed, and the insertion pipe 21 passes through it. Referring to Figure 6, the waist pipe 22 comprises a shaft base 23 formed approximately in the middle of its outer circumference and a fixing plate 24 formed at the rear end of its outer circumference.

The end formwork fixing beam 20 is rotatably installed on the beam support steel member 16 by a support member 50. The support member 50 consists of a rotatable support portion 51 and an extended portion 58.

Referring to Figure 7(a), the rotation support section 51 comprises a seat plate 52 fixed to the upper flange of the beam support steel member 16, and a pair of bearing plates 53 erected at a predetermined distance from each other on the upper surface of the seat plate 52 and facing each other. The pair of bearing plates 53 each have bearing holes formed at opposing positions, and these bearing holes support the rotation shafts 54a and 54b, which are composed of bolts or the like.

The pivot shaft 54a is inserted through the bearing hole 23a of the pivot base 23 of the end formwork fixing beam 20, and serves as the central axis of rotation for the end formwork fixing beam 20. Because the pivot base 23 is formed approximately in the middle of the waist pipe 22, the weight of the end formwork fixing beam 20 is distributed to both sides of the pivot shaft 54a, allowing the end formwork fixing beam 20 to be rotated with minimal force.

The base plate 52 is rectangular in shape and has adjustment screws 55 at each of its four corners. The adjustment screws 55 are an adjustment mechanism that adjusts the inclination of the pivot shaft 54a (base plate 52) by adjusting the length of the base plate 52's protrusion downwards. With the inclination adjusted using the adjustment screws 55, the base plate 52 is fixed to the upper flange of the beam support steel member 16 by tightening the fixing bolts 57 of the fixing angle 56, which extends to the lower part of the upper flange of the beam support steel member 16.

The beam support steel member 16 is shaped to conform to the circumference of the formwork 11. Therefore, if the rotation support portion 51 (base plate 52), which supports the rotation of the three end formwork fixing beams 20, is fixed directly to the upper flange of the beam support steel member 16, the rotation axes 54a of the three end formwork fixing beams 20 will each have different inclinations, as shown in Figure 8(a). In this case, the distance between the tips of the three end formwork fixing beams 20 changes with rotation. Consequently, the three end formwork fixing beams 20, whose tips are connected by a through member 40, cannot rotate or extend smoothly due to friction between the rotation axis 54a and the shaft base 23 (bearing hole 23a), and between the insertion pipe 21 and the waist pipe 22.

Therefore, in this embodiment, the inclination of the pivot shaft 54a (base plate 52) can be adjusted using the adjustment screw 55. By adjusting the inclination of the pivot shaft 54a (base plate 52) with the adjustment screw 55, the pivot shafts 54a of the three end formwork fixing beams 20 can be set parallel, as shown in Figure 8(b). This eliminates the gap, and the three end formwork fixing beams 20, whose ends are connected by the through-member 40, can rotate and extend smoothly.

Referring to Figure 7(b), the extension 58 comprises a pair of bearing plates 59 facing each other and a column member 60 extending downward from the beam support steel member 16. The pair of bearing plates 59 each have bearing holes 59a formed at opposing positions, and the extension 58, including the bearing plates 59, is fixed by passing the pivot shaft 54b through the bearing holes 59a. The pair of bearing plates 59 of the extension 58 are positioned between the pair of bearing plates 53 of the rotation support 51, and the shaft base 23 of the end formwork fixing beam 20 is pivotally supported by the pivot shaft 54a located between the pair of bearing plates 59 of the extension 58. Furthermore, the rotation support 51 is fixed to the lower flange of the beam support steel member 16 by a hook portion 61 in conjunction with fixing bolts 57.

The column member 60 is fixed to the lower flange of the beam support steel member 16 by the hook portion 61, and a fixing plate 62 is formed at its lower end.

The gas spring 70 is interposed between the fixing plate 24 of the waist pipe 22 and the fixing plate 62 of the extension 58. One end of the gas spring 70 is pivotally supported by the bearing hole 24a of the fixing plate 24, and the other end is pivotally supported by the bearing hole 62a of the fixing plate 62.

The gas spring 70 is a retractable type and functions as a biasing mechanism that pulls the rear end of the end formwork fixing beam 20 downward, thereby biasing the front end of the end formwork fixing beam 20 upward. The retraction force of the gas spring 70 is set to a force sufficient to slowly move the front end of the end formwork fixing beam 20 upward. In the example shown in Figure 3, the gas spring 70 is installed only on the middle end formwork fixing beam 20, but there are no restrictions on which end formwork fixing beams 20 the gas spring 70 can be installed on, and the number of gas springs 70 can be appropriately set according to their retraction force.

In this embodiment, the biasing mechanism, a gas spring 70, is installed on the face side of the beam support steel member 16. Therefore, the gas spring 70 does not obstruct the working space between the end face of the casting space C and the beam support steel member 16, thereby improving work efficiency. If there is sufficient working space, the gas spring 70 can also be installed as an extrusion type between the end face of the casting space C and the beam support steel member 16.

The gas spring 70 is an example of a biasing mechanism and can be replaced with a mechanism using various springs having appropriate biasing force. Alternatively, the pivot shaft 54a and the end formwork fixing beam 20 may be fixed, and the biasing mechanism may bias the pivot shaft 54a in the rotational direction.

The pair of bearing plates 59 of the extension 58 are provided with stopper holes 59b formed in opposing positions, so as not to overlap with the pair of bearing plates 53 of the rotation support 51. The stopper holes 59b are located on the rear end side of the end formwork fixing beam 20, relative to the rotation shaft 54a.

As shown in Figure 9, by shortening the extension length of the end formwork fixing beam 20 and pressing down its tip, inserting the pin 5 into the stopper hole 59b restricts the rotation of the end formwork fixing beam 20 due to the biasing force of the gas spring 70. In this state, the through member 40 at the tip of the end formwork fixing beam 20 is retracted from the end face of the pouring space C. Therefore, the end formwork fixing device 10 does not get in the way during centering movement in the reinforced concrete section.

When the pin 5 inserted into the stopper hole 59b is removed, the end formwork fixing beam 20 is rotated by the biasing force of the gas spring 70, and the tip of the end formwork fixing beam 20 moves upward. Therefore, the worker can adjust the extension length of the end formwork fixing beam 20 using the telescopic mechanism, and as shown in Figure 4, the through member 40 can be brought into contact with the end formwork 3 at an appropriate position according to the thickness of the concrete pouring space C. In other words, the biasing force of the gas spring 70 can assist manual work and improve the operability of the vertical movement of the through member 40.

As described above, this embodiment is a formwork fixing device 10 that supports the concrete pouring pressure by bringing a through member 40 into contact with a plurality of formworks 3 arranged in parallel on the end face of the formwork in the pouring space C between the inner surface of the tunnel and the formwork 11 of the centering 1. The device includes a formwork fixing beam 20 that supports the through member 40 at the end located on the end face side, and is rotatably installed on a beam support steel member 16 that spans across the end face at a distance from the end face in a shape that follows the circumference of the formwork 11, with the end being movable in the direction normal to the circumference of the formwork 11, and a gas spring 70 that functions as a biasing mechanism that biases the formwork fixing beam 20 upward in a direction that approaches the inner surface of the tunnel, and the formwork fixing beam 20 is equipped with an extension mechanism that adjusts the extension length that extends from the beam support steel member 16 toward the end face.
With this configuration, after the end formwork 3 is installed, the through members 40 can be easily installed on the end formwork 3 simply by adjusting the extension length of the end formwork fixing beams 20, thus further reducing the burden of the installation work of the through members 40 and end formwork fixing beams 20 on the end formwork 3. In other words, the biasing force of the gas spring 70 assists manual work, improving the operability of the up and down movement of the through members 40. As a result, the worker can concentrate on the task of fine-tuning the extension length of the end formwork fixing beams 20, making the work easy even for one person, and preventing problems such as the end formwork 3 coming loose or moving, regardless of who is performing the work.

After concrete pouring is complete, the through-member 40 and end formwork fixing beam 20 can be easily removed from the end formwork 3 by retracting the expansion mechanism. This eliminates the need to install and remove the through-member 40 and end formwork fixing beam 20 from the centering plate 1 after each concrete pour, allowing for quick and easy fixing of the end formwork 3.

Furthermore, in this embodiment, the end formwork fixing beam 20 is rotatably installed on the beam support steel 16 such that its rear end protrudes from the beam support steel 16 in the direction opposite to the end face.
This configuration distributes the weight of the end formwork fixing beam 20 to both sides of the pivot axis 54a, making the tip of the end formwork fixing beam 20 lighter. As a result, the end formwork fixing beam 20 can be rotated with less force, further improving its operability.

Furthermore, in this embodiment, the gas spring 70 pulls the rear end of the end formwork fixing beam 20 downward, away from the inner circumferential surface of the tunnel.
This configuration allows the biasing mechanism, the gas spring 70, to work without obstructing the working space between the end face of the casting space C and the beam support steel member 16, thereby improving work efficiency.

Furthermore, in this embodiment, the end formwork fixing beam 20 is installed on the beam support steel member 16 via a support member 50 that supports the pivot axis 54a of the end formwork fixing beam 20, the support member 50 comprises a column member 60 extending downward from the beam support steel member 16, and the gas spring 70 is interposed between the rear end side (fixing plate 24) of the end formwork fixing beam 20 and the column member 60 (fixing plate 62).
This configuration makes it possible to pull the rear end of the end formwork fixing beam 20 downward by the gas spring 70.

Furthermore, in this embodiment, the through member 40 is supported by being stretched across two or more end formwork fixing beams 20, and the end formwork fixing beams 20 are installed on the beam support steel members 16 via a support member 50 (rotation support part 51) that supports the rotation axis 54a of the end formwork fixing beam 20, and the support member 50 (rotation support part 51) is equipped with a tilt adjustment mechanism for adjusting the tilt of the rotation axis 54a.
This configuration allows each of the pivot axes 54a to be set parallel, so that the three end formwork fixing beams 20, whose ends are connected by through members 40, can be rotated and extended smoothly.

The present invention has been described above based on the embodiments. These embodiments are illustrative, and it will be understood by those skilled in the art that various modifications are possible in the combination of their respective components, and that such modifications also fall within the scope of the present invention.

1 Centering 2 Rail 3 End formwork 4 Camber 5 Pin 10 End formwork fixing device 11 Formwork 11a End formwork face 12 Jack 13 Mobile frame 14 Gate frame 15 Overhanging steel member 16 Beam support steel member 17 Angle member 20 End formwork fixing beam 21 Insertion pipe 22 Waist pipe 23 Axle base 23a Bearing hole 24 Fixing plate 24a Bearing hole 30 Gripping part 31 Pipe receiving part 32 Movable part 33 Bolt 40 Through member 50 Support 51 Rotating support part 52 Seat plate 53 Bearing plates 54a, 54b Rotating shaft 55 Adjustment screw 56 Fixing angle 57 Fixing bolt 58 Extension part 59 Bearing plate 59a Bearing hole 59b Stopper hole 60 Column member 61 Hook part 62 Fixing plate 62a Bearing hole 70 Gas spring C pouring space

Claims (5)

A formwork fixing device for supporting concrete placement pressure by bringing through members into contact with multiple end formworks arranged side by side on the end face in the placement space between the inner surface of the tunnel and the formwork of the centering structure,
The end of the through member is supported at the end located on the side of the end face, and the end is rotatably mounted on a beam support steel member that spans across the end face at a distance from it in a shape that follows the circumference of the formwork, so that the end can move in the direction normal to the circumference of the formwork.
The system includes a biasing mechanism that biases the end formwork fixing beam upward so that its tip approaches the inner circumferential surface of the tunnel,
The end formwork fixing device is characterized in that the end formwork fixing beam is equipped with an extension mechanism for adjusting the extension length that extends from the beam support steel material toward the end face. The end formwork fixing device according to claim 1, characterized in that the end formwork fixing beam is rotatably installed on the beam support steel material such that its rear end protrudes from the beam support steel material in the direction opposite to the end face. The biasing mechanism is characterized by pulling the rear end of the end formwork fixing beam downward, away from the inner circumferential surface of the tunnel, as described in claim 2. The end formwork fixing beam is installed on the beam support steel via a support that supports the pivot axis of the end formwork fixing beam,
The support member comprises a column member extending downward from the beam support steel member,
The gable formwork fixing device according to claim 3, characterized in that the biasing mechanism is interposed between the rear end of the gable formwork fixing beam and the column member. The aforementioned through member is supported by being stretched across two or more of the aforementioned end formwork fixing beams.
The end formwork fixing beam is installed on the beam support steel via a support that supports the pivot axis of the end formwork fixing beam,
The formwork fixing device according to claim 1, characterized in that the support member is provided with a tilt adjustment mechanism for adjusting the tilt of the pivot shaft.