JPH0444600A - Tunnel lining form device - Google Patents

Abstract

PURPOSE:To simplify work by working an invert form and a side form in the widening or shortening direction, to be interlocked with a bearing device for moving a form main-body upward or downward, and by forming a working mechanism for form-removing or setting. CONSTITUTION:When a form main-body 12 is deformed to be in a form- removing state from a widening state (setting state), in other words, to be in a shortening state in the radial direction, then an upper side form 18 is interlocked with an ascending or descending jack 25 on a bearing device 14, to be moved downward, and the lever rod 32 of an invert form working mechanism 30 is rotationally moved counter-clockwise, and an invert form 22 is moved upward. At the same time, along with the upward movement of the invert form 22, both side forms 20, 21 are interlocked inside a tunnel 1 by the spring force of the side form working jack 27 of a tensile spring mechanism, and are rotationally displaced. As a result, work can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an improvement of a formwork device for secondary lining used in shield construction methods for tunnels, sewers, etc.

[Prior Art] Generally, in tunnel shield construction methods, a formwork device is used to perform a secondary lining with concrete on the inner surface of a tunnel that has been completely lined. This type of formwork device for tunnel lining consists of two lifting support devices that are movable in the longitudinal direction of the tunnel, and a device that is placed between both lifting support devices so that it can be lifted and lowered by both lifting support devices. The formwork body generally has a pair of sides connected to each other via a hinge or a top form at one end in the circumferential direction so as to be relatively displaceable in the tunnel radial direction. and an inverted form disposed between the other ends of the side forms in the circumferential direction.

These forms are adapted to form a continuous cylindrical outer surface when the form body is in the expanded condition.

Furthermore, as an operating mechanism for expanding and contracting the formwork body in the radial direction, there has conventionally been a side form actuating jack for displacing both side forms relative to each other, and an invert form actuating jack for displacing an invert form relative to another form. A form-actuated jack is used.

When performing secondary lining of the tunnel inner surface using such a formwork device for tunnel lining, the formwork body is moved to the position where the secondary lining is to be performed by the lifting support device, and then the formwork body is moved to the position where the secondary lining is to be performed. The formwork is raised to a predetermined height position, and then the formwork body is set in an expanded state by operating each of the above-mentioned operating jack means, and the space between the cylindrical outer surface of the formwork body and the inner surface of the tunnel-next lining is set. Concrete for secondary lining is poured into the annular space of 0. Next, when the secondary lining is completed by hardening of the concrete, the above-mentioned operating jack means are operated again to shrink and deform the formwork body in the radial direction. After that, the formwork body is lowered by a predetermined amount by the lifting support device, thereby removing the formwork body from the secondary lining surface of the tunnel, and making it possible to move the formwork body to the next secondary lining position.

[Problems to be Solved by the Invention] In the conventional tunnel lining formwork device described above, in order to remove or set the formwork body, the side form and the invert form are moved in the expansion/contraction direction by an operating jack. This required work to operate and displace the formwork, and work to raise and lower the entire formwork body, making the work time-consuming.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a formwork apparatus for tunnel lining, which can simplify the demolding or setting work of the formwork body.

[Means for Solving the Problems, Effects] According to the present invention, as a first means for achieving the above object, the upper part of the tunnel is rotatable with respect to each other via the top form or the top hinge part. a substantially cylindrical form body having a pair of left and right side forms connected to the top form and an invert form disposed between the lower ends of both side forms facing the top form or the top hinge part; A lifting support device that supports the top form or top hinge portion of the formwork body in a vertically movable manner, a side form actuating mechanism for rotationally displacing both side forms in the radial direction of the tunnel, and a lifting support device. between the top form or the top hinge and the invert form so that the invert form is raised when the top form or the top hinge moves down according to the vertical movement of the top form or the top hinge. A formwork device for tunnel lining is provided, comprising a coupled invert form actuation mechanism.

In the configuration of the first means, the invert form is operated so as to move upward when the top form or the top hinge portion descends in conjunction with the vertical movement of the top form or the top hinge portion. Therefore, there is no need to separately expand and contract the top form or the top hinge portion and the invert form. Therefore, the work for demolding and setting the formwork body is simplified, and workability is improved.

In the above configuration, preferably, the side form actuating mechanism comprises tension spring means that constantly urges both side forms inward in the radial direction of the tunnel.

With this configuration, when the top form or the top hinge section is lowered, the invert form can be raised in conjunction with the movement of the top form, and both side forms can be pulled up by the tension spring means. The spring force allows for rotational displacement inward of the tunnel. Therefore, the demolding operation of the formwork body is further simplified.

According to the present invention, as a second means for achieving the above object, a pair of left and right side forms rotatably connected to each other via a top form at the upper part of the tunnel, and a top form. a substantially cylindrical formwork body having an inverted form disposed between the lower ends of both sideforms to face each other; a support device for supporting both sideforms of the formwork body within a tunnel; The supporting device includes a base, a support arm provided on the base, and a side form actuating mechanism for rotating and displacing the tunnel in the radial direction of the tunnel. A pair of side arms are fixed to the support arm, so that both side forms are rotatable around the pivot point of the side arm to the support arm, and the pivot point of both side forms to the top form is rotatable about the pivot point of the side arm to the support arm. , the top form is disposed outward in the tunnel radial direction from the pivot points of both side arms relative to the support arm so that the top form rotates inward of the tunnel in conjunction with both side forms; The device includes an invert that connects the crown form and the invert form so that when the crown form moves inward of the tunnel in response to movement of the crown form in the tunnel radial direction, the invert form moves inward of the tunnel. A formwork device for tunnel lining is provided, which is characterized by being provided with a form actuation mechanism.

In the configuration of the second means, the top form also moves in the tunnel radial direction in response to the rotational displacement of both side forms in the tunnel radial direction, for example, when the side forms rotate inward of the tunnel. Therefore,
In conjunction with the demolding operation of the side forms, the top form also performs a demolding operation. Furthermore, the inverted form is linked to the movement of the crown form in the tunnel radial direction, for example, when the crown form moves inward, it also moves inward, so the escape of the crown form is prevented. In conjunction with the mold operation, the invert form also performs a mold removal operation. In other words, in conjunction with the demolding operation of the side form, the top form and the invert form will also perform the demolding operation, so for demolding work, both side forms are rotated by operating jacks. That alone is a good thing. The demolding operation is therefore significantly simplified. Of course, even in the setting operation of rotationally displacing the side forms outward in the radial direction of the tunnel, the top form and the inverted form can be similarly linked to the movement of the side forms.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 show a first embodiment of the present invention. First, referring to FIG. 1, a cylindrical primary lining 2 made of segments is provided on the inner surface of a tunnel l excavated by a shield excavator, for example, to have a circular cross section.

Formwork for secondary tunnel lining constructed according to the present invention
llo is provided with a cylindrical form body 12 that is disposed within the primary lining 2 of the tunnel 1 and forms an annular space between it and the inner surface for a secondary lining made of concrete, The form body 12 is supported by two traveling lifting support devices 14 that are movable in the tunnel 1 in its longitudinal direction. In addition, only one support device 14 is illustrated in the figure, and the illustrated support device 14 has wheels 1 for traveling on a base 15.
6, but the other support device usually has a sled on the base. Otherwise, both support devices are of substantially identical construction.

In FIG. 1, the form body 12 has been used for the secondary lining 3 with concrete, and then has been moved to the location where the next secondary lining is to be performed.

Particularly with reference to FIG. 2, in this embodiment, the formwork main body 12 includes a top form 18 disposed on the top side within the tunnel l, and a pair of side forms disposed on both sides within the tunnel l. It has forms 20 and 21, and an inverted form 22 arranged between both side forms 20 and 21 on the lower side inside the tunnel 1.

The upper end of both side forms 20 and 21 is the top form 1.
8 is rotatably connected to both ends in the circumferential direction via hinges 23 and 24, respectively. Both circumferential ends of the invert form 22 are formed so as to be able to approach and separate from the lower ends of both side forms 20.21. The form body 12 is in its maximum expanded state when the circumferential ends of these forms are in contact with each other, forming a continuous cylindrical outer surface.

Therefore, an annular secondary lining space is defined between the inner surface of the primary lining of the tunnel and the inner surface of the primary lining of the tunnel. Generally, the form body 12 has a structure in which a plurality of cylindrical form units having the above-mentioned form structure are connected in the longitudinal direction. Therefore, by selecting the number of connected formwork units, the total length of the formwork body 12 can be appropriately set depending on the curved state of the tunnel 1 and the like.

The support device 14 includes a lifting jack 2 erected on a base 15.
5 and an upper arm 26 that is raised and lowered by the jack 25, and the upper arm 26 extends in the longitudinal direction of the tunnel and is connected and fixed to the top foot 18 of the form body 12. That is, the top form 18 of the form body 12 is supported via the upper arm 26 by the lifting jack 25 of the support device 14 so as to be able to rise and fall.

The formwork apparatus is equipped with side form actuating jacks 27 for rotationally displacing both side forms 20.21 in the tunnel radial direction with respect to the top form 18. The actuating jack 27 may be arranged inside the formwork body 12, but in this embodiment, both ends of the actuating jack 27 extend from the side forms 20.21 to the formwork body 12, respectively.
a pair of side arms 28, 2 extending outward in the longitudinal direction of 2;
It is connected to 9. Therefore, passage inside the form body 12 and various operations inside the form body are facilitated.

The actuating jack 27 may have a turnbuckle-type extendable rod structure, but here the actuating jack 27 has a tension spring structure.

Therefore, both side forms 20, 21 are always urged inward in the radial direction of the tunnel by their spring force, and when the form body 12 is expanded, the inverted forms 22 are urged outward in the radial direction of the tunnel against the spring force. This means that it has been rotationally displaced.

The invert form actuation mechanism that characterizes the present invention is the first
It is generally designated by the reference numeral 30 in the Figures and FIG.

This invert form actuating mechanism 30 is a lifting support device 1
The top form 18 and the invert form 22 are connected so that the invert form 22 is raised when the top form 18 is lowered according to the vertical movement of the top form 18 by the movement of the top form 18 and the invert form 22.

More specifically, the invert form actuation mechanism 30 includes a column 31 erected on the base 15 of the support device 14, and a lever whose middle portion is pivotally supported by the column 31 and whose both ends are vertically swingable. The lever 32, one end of the lever 32, and the top form 1
8 and a second connecting rod 34 that connects the other end of the lever rod 32 and the invert form 22. Furthermore, in this embodiment, the first connecting rod 33
The top form 18 is connected to the top form 18 via the upper arm 26 extending outward in the longitudinal direction of the form body 12 from the top form 18.
The second connecting rod 34 is connected to the invert form 22 via a lower arm 35 extending outward in the longitudinal direction of the form body 12 from the invert form 22 . More specifically, the second connecting rod 34 is connected to the lower arm 3.
It is rotatably connected to a bracket 35a fixed to 5 via a shaft 35b.

Generally, the amount of movement of the invert form 22 required for demolding the form body 12 is larger than the amount of movement of the top form 18. The length ratio of the second connecting rods 33 and 34 to the connecting portions 32b and 32c is smaller than the amount of movement of the top form 18.
The amount of movement is set to be larger than that of .

In the formwork apparatus for tunnel lining having the above configuration, for example, the formwork main body 12 is changed from the expanded state shown in FIG. When deforming to the contracted state, when the top form 18 is lowered by the lifting jack 25 on the support device 14, the lever 32 is rotated counterclockwise in FIG. 1, and the inverted form 22 is moved upward. It will be lifted up. As the invert form 22 moves upward, both side forms 20.
21 is a side form actuation jack 2 with a tension spring structure.
It will be rotationally displaced inward of the tunnel by the spring force of 7.

That is, in this embodiment, the inverted form 22 and both side forms 2 are moved by lowering the top form 18 using the lifting jack 25, that is, by removing the mold from the top form 18.
0.21 can be demolded at the same time. Therefore, demolding of the form body 12 can be performed extremely easily and quickly.

If a rod-type side form actuating jack is used, the top form 18 is lowered after removing it from the side arms 28, 29 during demolding. At this time, as the invert form 22 rises, the side forms 20.21 can be displaced inward of the tunnel. In order to further displace both side forms 20.21 inward of the tunnel, for example, a chain jack or the like is connected between the side arms 28 and 29, and this chain jack is used to move both side forms 20.21 inward of the tunnel. It may also be rotated.

On the other hand, when setting the form body 12 at a location where secondary lining is required, the invert form 22 is raised by raising the top form 18 with the lifting jack 25.
As the invert form 22 descends, both side forms 20 and 21 are pushed out of the tunnel by the invert form 22 against the spring force. In addition, when using a rod-type side form actuating jack, both side forms 20, 21 can be used to rotationally displace the both side forms 20, 21 outward in the radial direction of the tunnel in advance.

3 and 4 show a second embodiment of the present invention. In these figures, the same reference numerals are given to the same components as in the above embodiments, and detailed explanations will be omitted.

In this second embodiment, both side forms 20.21 of the form body 12 are rotatably connected to each other via the top hinge portion 40, and the top hinge portion 40
is supported via an upper arm 26 by an elevating jack 25 of the support device 14 so as to be movable up and down. That is, the top form is omitted in this embodiment.

Therefore, in this second embodiment, the first connecting rod 33 of the invert form actuating mechanism 30 is connected to the upper arm 26.
It is connected to the top hinge part 40 via.

The other configurations of the second embodiment can be the same as those of the first embodiment.

Therefore, in this second embodiment as well, as in the first embodiment, by raising and lowering the top hinge portion 40, the mold main body 12 can be quickly and easily removed from the mold and set.

5 to 7 show a third embodiment of the present invention. In these figures, the same reference numerals are given to the same components as in the first embodiment, and detailed explanations will be omitted.

In this embodiment, the formwork main body 12 has a top form 18, both side forms 20.21, and an inverted form 22.
1 are rotatably connected to both circumferential ends of the top form 18 via hinges 23 and 24, respectively.

On the other hand, the support device 14 includes an arm 42 supported by a column 41 (this column does not need to be a lifting jack),
At both ends of this arm 42 are side arms 43,
The upper end of 44 is rotatably supported via hinges 45 and 46, and both side arms 43 and 44 are connected and fixed to side forms 20 and 21, respectively. Therefore, both side forms 20.21 of the formwork body 12 are connected to the arm 4 of the support device 14 via the side arms 43, 44.
2, and is rotatably supported around hinges 45 and 46 as fulcrums.

Here, the inter-axle ratio HD of the hinges 45 and 46 is set larger than the above-described inter-axle distance of the hinges 23 and 24. In other words, the hinges 23 and 24 are the hinges 45,
46 in the tunnel radial direction. Therefore, when the side forms 20, 21 rotate around the hinges 45° 46, the top form 18 is displaced up and down, while the supporting device! On the base 15 of No. 14, an inverted form 22 is mounted on the base 15 of the tunnel 14, so that when the top form 18 moves inward (downward) of the tunnel in accordance with the movement of the top form 18 in the tunnel radial direction (up and down movement), the inverted form 22 an invert form actuating mechanism 3 that connects the top form 18 and the invert form 22 so as to move the top form 18 and the invert form 22;
0 is set. The configuration of this actuator 30 is substantially the same as the actuator mechanism 30 of the first embodiment described above,
The first connecting rod 33 of the actuating mechanism 30 is connected to an upper arm 47 that extends outward in the longitudinal direction of the form body 12 from the top form 18, and the second connecting rod 34 extends outward in the longitudinal direction of the form body 12 from the inverted form 22. outwardly extending lower arm 35
is connected to. Therefore, the inverted form 2
2 moves upward or downward in conjunction with the vertical movement of the top form 18.

In this embodiment, the side form actuating jack 2
7 has a turnbuckle rod type structure, or
A jack that can be expanded and contracted using hydraulic pressure is used.
In the illustrated embodiment, this actuating jack 27 is arranged coupled between the two side arms 43,44.

In the third embodiment having the above configuration, when both side forms 20.21 are rotated, for example, in the demolding direction (inward the tunnel) by the operating jack 27, the top form 18 is accordingly rotated in the demolding direction (inward the tunnel). The inverted form 22 is moved in the demolding direction (upward, ie, inside the tunnel) as the two-top form 18 is demolded.

In this way, in the third embodiment, by rotating both side forms 20, 21, the mold main body 12 can be quickly and easily demolded or set.

In addition, as a modification of the third embodiment, the above-mentioned shaft pressure +! ! D
1. If the relationship D2 is set as =D2, even if the pair of side forms 20 and 21 are rotated, the top form 1
8 is not linked to the movement of the side forms 20 and 21. Therefore, in this case, the upper arm 47 or the lower arm 35 may be moved up and down by additional jacking means or other actuation mechanism, or the invert form actuation mechanism 30 may be driven by a similar actuation mechanism. be able to.

FIGS. 8 and 9 show a fourth embodiment of the present invention. In these figures, the same reference numerals are given to the same components as in the first embodiment, and detailed explanations will be omitted.

In this fourth embodiment, the invert form 22 is pivotally attached to one side form (here, the right side form 20 in FIG. 9) via a hinge 48.

Therefore, the invert form 22 is removed from the inner surface of the secondary lining of the tunnel by rotationally displacing the invert form 22 from the position shown in FIG. 9 to the inside of the tunnel, that is, upward in the figure, about the axis of the hinge 48.

Formwork body 1 having such an inverted form 22
In case 2, the invert form actuating mechanism 30 operates the invert form 22 when the top form 18 is lowered in accordance with the lifting and lowering movement of the top form 18 by the lifting support device 14, as in the case of the first embodiment. The invert form actuating mechanism 30 of the fourth embodiment is provided between the top form 18 and the invert form 22 so as to be raised, but since the invert form 22 is rotationally displaced, the invert form actuating mechanism 30 of the fourth embodiment is similar to the invert form actuating mechanism of the first embodiment. The mechanism is slightly different.

That is, the invert form actuating mechanism 30 in the fourth embodiment includes a column 31 erected on the base 15 of the support device 14, an intermediate portion of which is pivotally supported by the column 31, and both ends of which are swingable up and down. A first connecting rod 33 that connects one end of the lever 32 and the top form 18, and a second connecting rod 34 that connects the other end of the lever 32 and the inverted form 22. The first connecting rod 33 is connected to the top form 18 via the upper arm 26 extending outward in the longitudinal direction of the form body 12 from the top form 18, and the second connecting rod 34 is Invert form 22
a lower arm 3 extending longitudinally outwardly from the formwork body 12;
5 to the invert form 22.

More specifically, as shown in FIG. 9, the lower arm 35 is formed with an elongated guide hole 35d that extends approximately in the direction of the rotation radius of the invert form 22. Shaft 3 slidably engaged
For the bracket 35a with 5C, the second connecting rod 34
are rotatably connected via a shaft 35b. Other configurations in the fourth embodiment are similar to those in the first embodiment.

Therefore, in this fourth embodiment, when the top form 18 is demolded downward in FIG. 9, the second connecting rod 34 of the invert form actuating mechanism 30 is lifted upward in the figure. , shaft 35 of bracket 35a
c slides within the guide 6 35d, and the invert form 22 is pulled upward in the figure around the axis of the hinge 48. Therefore, in this embodiment as well, the same effects as in the first embodiment can be obtained.

Although the illustrated embodiments have been described above, the present invention is not limited to the embodiments described above, and various changes can be made to the constituent elements within the scope of the invention described in the claims. For example, the operating mechanism such as the operating jack in each embodiment may be hydraulic as described above.

Moreover, it is also possible to configure the side forms to be individually rotated and displaced by an actuating mechanism.

Furthermore, the side form in the fourth embodiment may be rotatably connected via a hinge at the top end, similarly to the side form in the second embodiment.

Furthermore, as can be easily seen from the configuration of the fourth embodiment, the present invention can be similarly applied to a formwork body in which a pair of invert forms are each pivotally connected to a pair of side forms. In this case, a pair of invert form actuation mechanisms similar to the invert form actuation i#t30 used in the fourth embodiment may be applied to each of the pair of invert forms.

Furthermore, the first connecting rod 32 or the second connecting rod in each of the above embodiments
By making at least one of the connecting rods 34 have a jack structure that can be expanded and contracted in the length direction, the top form 18 or the hinge 40 and the inverted form 22
The height positional relationship can be adjusted.

[Effects of the Invention As is clear from the above explanation, according to the configuration of the present invention,
It is possible to provide a formwork device for tunnel lining that can quickly and easily perform demolding and setting operations of the formwork body.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic vertical sectional view of the main parts of a tunnel lining formwork device showing a first embodiment of the present invention, and FIG. 2 is a first embodiment of the formwork device shown in FIG. 1. 3 is a schematic vertical sectional view of the main part of a tunnel lining formwork device showing a second embodiment of the present invention; FIG. 4 is a sectional view of the mold shown in FIG. 3; A cross-sectional view of the frame device taken along the line ■-■ in FIG. 3, FIG. 5 is a schematic cross-sectional view showing the support device of the formwork device shown in FIG. 5; FIG. 7 is a schematic cross-sectional view of the formwork body of the formwork device shown in FIG. 5. FIG. 8 is a schematic longitudinal cross-sectional view of main parts of a formwork device for tunnel lining showing a fourth embodiment of the present invention, and FIG. In the figure, 10 is a formwork device, 12 is a formwork body, 14 is a support device, 15 is a base, 18 is a top form, 20.2
1 is side form, 22 is inverted form, 23
24 is a hinge, 25 is a lifting jack, 26 is an upper arm, 27 is a side form operating jack, 30 is an invert form operating mechanism, 31 is a column, 32 is a lever, 33
is the first connecting rod, 34 is the second connecting rod, 35 is the lower arm,
35a is a bracket, 35b and 35c are shafts, 35d
is a guide hole, 40 is a top hinge part, 43.44 is a side arm, 45.46 is a hinge, 47 is an upper arm, 48
indicates a hinge, respectively.

Claims (1)

[Claims] 1. A pair of left and right side forms rotatably connected to each other via a top form or a top hinge part at the upper part of the tunnel, and a pair of side forms facing the top form or top hinge part. a generally cylindrical form body having an inverted form disposed between the lower ends of both side forms; and an elevating support that supports the top form or the top hinge part of the form body in a tunnel so that it can rise and fall. a device, a side form actuating mechanism for rotationally displacing both side forms in the radial direction of the tunnel, and a side form actuating mechanism for rotationally displacing both side forms in the radial direction of the tunnel; A formwork device for tunnel lining, comprising: an invert form actuating mechanism that connects the top form or the top hinge part and the invert form so as to raise the invert form when the part descends. 2. The elevating support device includes a base and an elevating jack that is erected on the base and supports the top form or the top hinge portion in a vertically movable manner; A first connection that connects one end of the lever and the top form or the top hinge part. The formwork apparatus according to claim 1, comprising a rod and a second connecting rod that connects the other end of the lever and the invert form. 3. The length from the pivot point of the lever to the column to the connecting portion of the first and second connecting rods is set so that the amount of movement of the invert form is greater than the amount of movement of the top form or the top hinge portion. The formwork device according to claim 2, wherein the formwork device is 4. The first connecting rod is connected to the top form or the top hinge part via an upper arm extending outward in the longitudinal direction of the formwork body from the top form or the top hinge part, and the second connecting rod The formwork device according to claim 2, wherein the invert form is connected to the invert form via a lower arm extending outward in the longitudinal direction of the form body from the invert form. 5. The formwork apparatus according to claim 1, wherein the side form actuating mechanism is a tension spring means that constantly urges both side forms inward in the radial direction of the tunnel. 6. A pair of left and right side forms rotatably connected to each other via the top form at the upper part of the tunnel, and an invert form disposed between the lower ends of both side forms facing the top form. a substantially cylindrical form body having a shape, a support device for supporting both side forms of the form body within the tunnel, and a side form actuating mechanism for rotationally displacing both side forms in the radial direction of the tunnel, The support device is
It includes a base, a support arm provided on the base, and a pair of side arms pivotally connected to both ends of the support arm and fixed to both side forms, whereby both side forms are fixed to the support arms. The side arm is rotatable around the pivot joint, and the pivot joints of both side forms to the top form allow the top form to rotate inward of the tunnel in conjunction with both side forms. The supporting device is disposed outward in the tunnel radial direction from the pivot points of both side arms relative to the support arm, and the support device further includes a support device that allows the top form to move in the tunnel radial direction in response to movement of the top form in the tunnel radial direction. A formwork device for tunnel lining, characterized in that it is provided with an invert form actuation mechanism that connects the top form and the invert form so that the invert form moves inward of the tunnel when moving inward. 7. The invert form operating mechanism consists of a pillar installed on a base, a lever whose middle part is pivoted to the pillar and whose both ends can swing up and down, and one end and the top of the lever. The formwork device according to claim 6, comprising a first connecting rod that connects the invert form and a second connecting rod that connects the other end of the lever and the invert form. 8. The length from the pivot point of the lever to the column to the connecting portion of the first and second connecting rods should be such that the amount of movement in the tunnel radial direction of the inverted form is greater than the amount of movement in the tunnel radial direction of the top form. Claim 7 has been set.
Formwork equipment described in. 9. The first connecting rod is connected to the top form via an upper arm extending outward in the longitudinal direction of the form body from the top form, and the second connecting rod is connected from the invert form to the longitudinal direction of the form body. Formwork apparatus according to claim 7, connected to the invert form via a lower arm extending outwardly in the direction.