JP7852918B2 - Formwork alignment jig - Google Patents

Description

This invention relates to a formwork alignment jig used in concrete foundation construction.

Conventionally, in concrete foundation construction for houses and other buildings, a jig called a "sway-preventing support" (also simply called a "support" or "supporter") has been used to prevent the formwork from tilting outwards (see, for example, Patent Document 1).

This anti-sway support is a rod-shaped member made of metal or the like. One end is attached to the upper outside of the formwork, and the other end is fixed to the ground via a stake-like member. This presses the formwork from the outside inward (towards the side where the reinforcing bars are placed), preventing it from tilting.

On the other hand, when constructing foundation concrete using formwork, a device called a donut-shaped resin-molded rebar spacer is widely used to maintain a predetermined distance (referred to as "cover") between the inner surface of the formwork and the foundation reinforcement (see, for example, Patent Document 2). This rebar spacer is attached to key points on the foundation reinforcement, and its outer frame abuts against the inner surface of the formwork, thereby maintaining the predetermined distance between the inner surface of the formwork and the foundation reinforcement.

However, if the rebar spacers are not properly embedded, such as if a portion of them protrudes from the foundation concrete, there is a problem in that they may affect the strength of the foundation concrete. To solve this problem, a rebar spacing retainer has been proposed that can maintain a predetermined distance between the inner surface of the formwork and the foundation rebar without affecting the strength of the foundation concrete (see, for example, Patent Document 3).

Japanese Patent Publication No. 2014-173349 Japanese Patent Application Publication No. 10-238018 Utility Model Registration No. 3232252 Gazette

In the conventional formwork support method disclosed in Patent Document 1, the formwork is supported solely by external pressure. Therefore, if the connected formworks twist from side to side, it becomes difficult to align multiple formworks in a straight line (formwork alignment).

On the other hand, while the conventional rebar spacing holders disclosed in Patent Documents 2 and 3 can maintain the spacing between the inner surface and the rebar in individual formwork, the spacing is constant and fine adjustment is impossible, and it is not possible to correct the twisting of the formwork.

This invention has been made in view of the above-mentioned problems, and aims to provide a formwork alignment jig that can linearly align formwork while maintaining a predetermined distance between the formwork and the reinforcing bars.

The formwork alignment jig according to the present invention is a jig used to align formwork when forming a concrete foundation, by being attached between formwork and reinforcing bars so as to press the inner surface of the formwork that faces the reinforcing bars , and comprises a jig body having a base having a predetermined length in the longitudinal direction and a flat plate portion provided intersecting one end of the base for pressing the inner surface of the formwork , and a movable fixing device having an engagement hole for engaging with the reinforcing bars and provided so as to be able to adjust its relative position in the longitudinal direction with respect to the base, and a fixing member for detachably fixing the engagement member to the reinforcing bars.

In this configuration, the engaging member of the movable fixing device engages with the reinforcing bar in the engaging hole and is fixed to the reinforcing bar while adjusting its relative position in the longitudinal direction with respect to the base of the jig body. In this state, the flat plate portion provided at one end of the base presses against the inner surface of the formwork. In other words, the flat plate portion provided at one end of the base, whose relative position to the engaging member that engages with the reinforcing bar is appropriately adjusted, presses against the inner surface of the formwork from the reinforcing bar side. This corrects the twisting of the formwork arranged in multiple rows in the width direction and maintains the appropriate spacing between the formwork and the reinforcing bar. Therefore, it has the effect of aligning the formwork in a straight line while maintaining a predetermined spacing between the formwork and the reinforcing bar.

Furthermore, the base portion has an elongated hole extending in the longitudinal direction, and the engaging member has a protrusion that is inserted into the elongated hole. The engaging member is fixed to the base portion via the fixing member when the protrusion is inserted at any position in the elongated hole in the longitudinal direction.

In this configuration, the protrusion on the engaging member is inserted into any position along the longitudinal direction of the elongated hole in the base, and the engaging member is fixed to the base via the fixing member. Therefore, the engaging member and the base can be securely fixed while easily and appropriately adjusting their relative positions in the longitudinal direction.

Furthermore, the base is a metal fitting with a U-shaped cross-section, and the engaging member is a metal fitting with a U-shaped cross-section that is placed on top of the inside of the base. The engaging member is fixed to the base and the reinforcing bar by having a bolt, which acts as a protrusion, provided on the opposing surface of the base facing the elongated hole-forming surface, inserted into the elongated hole, and fastening by screwing a nut, which acts as a fixing member, onto the portion of the bolt protruding from the elongated hole.

According to this configuration, the engaging members are stacked on the inside of the base, and nuts are screwed onto the protruding portion of the bolt provided in the engaging member through the elongated hole in the base. By fastening at any position in the longitudinal direction, the engaging members can be securely fixed to the base and reinforcing bars with a simple structure.

Furthermore, the flat plate portion has an elastic body provided on the surface opposite to the base portion.

With this configuration, the flat plate section can apply a surface-level pressing force to the formwork while the elastic force of the elastic material ensures that it adheres securely to the inner surface of the formwork.

Furthermore, the engaging member has a triangular portion formed on a part of the inner circumference contour of the engaging hole.

This configuration allows for stable engagement with multiple types of reinforcing bars of different outer diameters, as a triangular portion is formed on a part of the inner contour of the engagement hole.

Furthermore, the engaging member is formed in a C-shape, with a portion of the circumferential direction of the engaging hole being open.

With this configuration, the side of the reinforcing bar can be inserted through an opening formed in a part of the circumferential direction of the engagement hole. Therefore, not only vertical reinforcing bars but also horizontal reinforcing bars can be engaged with the engagement hole at any desired position, allowing the formwork fitting jig to be attached between the formwork and the reinforcing bars.

This is a perspective view showing the overall configuration of a formwork alignment jig according to an embodiment of the present invention. This is another perspective view showing the overall configuration of the formwork alignment jig according to the embodiment. This is a front view showing a formwork alignment jig according to an embodiment. This is a rear view showing a formwork alignment jig according to an embodiment. This is a right side view showing a formwork alignment jig according to an embodiment. This is a left side view showing a formwork alignment jig according to an embodiment. This is a plan view showing a formwork alignment jig according to an embodiment. This is a bottom view showing a formwork alignment jig according to an embodiment. This is a front view showing an engaging member according to an embodiment. This is a rear view showing the engaging member according to the embodiment. This is a right side view showing an engaging member according to an embodiment. This is a plan view showing an engaging member according to an embodiment. This is a cross-sectional view of a construction site showing the process from pouring lean concrete to installing the outer formwork. This is a cross-sectional view of a construction site showing the process of installing jigs according to the formwork. This is an enlarged view of the area indicated by the XV arrow in Figure 14. This is a plan view of a construction site showing the process of installing jigs according to the formwork. This is an enlarged view of the area indicated by line XVII in Figure 16. This is a cross-sectional view of the construction site showing the base concrete pouring process. This is a cross-sectional view of a construction site showing the process of installing the inner formwork. This is a cross-sectional view of a construction site showing the process of pouring the strip foundation. This is a cross-sectional view of the construction site after the formwork removal process. This is an explanatory diagram showing a front view of the formwork jig attached to the horizontal reinforcement bars. This is a diagram illustrating, in plan view, how the formwork jig is attached to the horizontal reinforcement bars. This is a perspective view showing the overall configuration of the formwork alignment jig according to the first modified example. This is a cross-sectional view of a construction site showing the process of installing a formwork alignment jig related to the second modified example.

The following describes one embodiment of the formwork alignment jig according to the present invention, with reference to the drawings.

<Configuration of the formwork alignment jig>
First, the configuration of the formwork alignment jig 1 according to an embodiment of the present invention will be described with reference to Figures 1 to 12. Figure 1 is a perspective view showing the overall configuration of the formwork alignment jig 1, Figure 2 is another perspective view, Figure 3 is a front view, Figure 4 is a rear view, Figure 5 is a right side view, Figure 6 is a left side view, Figure 7 is a top view, and Figure 8 is a bottom view. Figure 9 is a front view showing the movable fixing device 20, Figure 10 is a rear view, Figure 11 is a right side view, and Figure 12 is a top view.

The formwork alignment jig 1 is used, for example, in the two-stage concrete pouring method for raft foundations in residential and other concrete foundation construction, where concrete is poured in two stages: the base section and the strip foundation section. It is used to align multiple formwork pieces arranged along the perimeter of the site in a straight line (formwork alignment). The formwork alignment jig 1 also has the function of maintaining the spacing between the formwork and the reinforcing bars.

As shown in Figures 1 to 8, the formwork alignment jig 1 comprises a jig body 10 and a movable fixing device 20.

The jig body 10 is composed of a base portion 12 and a flat plate portion 13 that is arranged perpendicularly to one end face in the longitudinal direction of the base portion 12 and joined to it. The base portion 12 is made by bending a metal plate and has an elongated rectangular shape that extends to a predetermined length in the horizontal direction when viewed from above, and has a U-shaped cross-section with an opening on the front side. The base portion 12 is made of, for example, a hot-dip galvanized steel plate with a thickness of about 2 to 3 mm and is set to a predetermined length (for example, about 60 mm to 100 mm) that is greater than or equal to the required distance (for example, 40 mm) between the inner surface of the formwork and the reinforcing bars. By making the base portion 12 have a U-shaped cross-section, the weight can be reduced while ensuring the necessary rigidity. An elongated hole 12a extending in the longitudinal direction is opened on the back surface of the base portion 12 (that is, the back surface of the base portion 12 corresponds to the elongated hole forming surface of the present invention). Furthermore, multiple scales 12b are engraved at equal intervals along the longitudinal edge of the upper and lower surfaces of the base 12. These scales 12b are used as markers to visually confirm the distance L (see Figures 15 and 17 described later) between the inner surface of the formwork and the reinforcing bars when installing the formwork alignment jig 1 between the formwork and the reinforcing bars.

The flat plate portion 13 is the part that presses against the inner surface of the formwork and is made of a rectangular metal plate. For example, the flat plate portion 13 is made of an electro-galvanized steel plate with a thickness of about 2 to 3 mm and has a rectangular shape of about 60 mm x 60 mm to 60 mm x 80 mm. One side of the flat plate portion 13 is joined to one end face in the longitudinal direction of the base portion 12 (the left end face in Figures 3 and 7) by welding, and is integrated with the base portion 12.

A rubber sheet 14 is attached to the side of the flat plate portion 13 opposite to the base portion 12 using adhesive. The rubber sheet 14 is an elastic rubber plate, formed in a rectangular shape and size that matches the flat plate portion 13. The rubber sheet 14 is made of, for example, natural rubber. The flat plate portion 13 can be securely attached to the inner surface of the formwork by applying a surface-level pressing force to the formwork while utilizing the elastic force of the rubber sheet 14.

The movable fixing device 20 is comprised of an engaging member 21 and a wing nut 23.

The engaging member 21 is a metal fitting having an engaging hole 21c for engaging with the reinforcing bar and being provided so as to be adjustable relative to the base 12 in the longitudinal direction. As shown in Figures 9 to 12, the engaging member 21 is C-shaped in plan view and U-shaped in cross-section, having upper and lower parallel surfaces 21a, 21a and a right-angle end surface 21b connecting them on the back side, and is equipped with a bolt 22 fixed to the right-angle end surface 21b. The vertical height of the outer surface of the engaging member 21 is set to be smaller than the vertical height of the inner surface of the base 12, and is positioned to be inserted into the U-shape of the base 12 and overlapped.

In the engaging member 21, engaging holes 21c, 21c are formed on the upper and lower parallel surfaces 21a, 21a, respectively, into which reinforcing bars are inserted and engaged. The engaging member 21 is formed in a C-shape with a part of the circumferential direction of each engaging hole 21c being open. The contour of the engaging hole 21c is a pentagonal shape in plan view, combining a rectangle and an isosceles triangle, with the vertex of the triangular portion 21d formed on the front side. The inner diameter of the engaging hole 21c is set to a size that can engage with multiple types of reinforcing bars with different outer diameters. For example, if the outer diameters of the reinforcing bars are 10 mm, 13 mm, and 16 mm, the inner diameter of the engaging hole 21c is set to 16 mm or larger. Since the reinforcing bar abuts against the two equal sides of the triangular portion 21d in the engaging hole 21c, regardless of the outer diameter, engagement will occur at the center of the engaging hole 21c in the left-right direction (longitudinal direction of the base 12). A through-hole is formed in the orthogonal end face 21b, through which the leg of the bolt 22 is inserted.

A known flat-head bolt is preferably used for the bolt 22. The bolt 22 has its foot inserted through a through-hole in the orthogonal end face 21b, from the inside to the outside (from the front to the back) of the engaging member 21, and the back surface of the head is joined to the inner surface of the orthogonal end face 21b by welding. The foot of the bolt 22 protrudes to the back side through the elongated hole 12a when the engaging member 21 is inserted inside the base 12. The foot of the bolt 22 is relatively movable in the longitudinal direction (left-right direction in Figures 3 and 7) within the elongated hole 12a. Therefore, by sliding the engaging member 21 and the base 12 relatively in the longitudinal direction while the foot of the bolt 22 and the elongated hole 12a are guided relative to each other, the relative positions of the two members can be adjusted. Thus, the gap between the reinforcing bar and the formwork can be adjusted while the engaging member 21 is attached to the reinforcing bar.

The wing nut 23 is a known nut that can be tightened or loosened by gripping it with the fingers without using tools, and constitutes the fixing member of the present invention. The wing nut 23 is screwed onto the leg of the bolt 22 protruding to the rear side through the elongated hole 12a, with the engaging member 21 positioned overlapping the base 12. After adjusting the longitudinal relative position of the engaging member 21 with respect to the base 12, the base 12 and the engaging member 21 are fastened together with the wing nut 23, thereby fixing the engaging member 21 to the base 12 and simultaneously fixing it to the reinforcing bars inserted into the engaging holes 21c, 21c.

<How to use the formwork alignment jig>
Next, the method of using the formwork alignment jig 1 according to this embodiment will be explained using the two-pass concrete slab foundation construction method as an example, with reference to Figures 13 to 17. Figure 13 is a cross-sectional view of the construction site showing the lean concrete pouring process to the outer formwork installation process. Figure 14 is a cross-sectional view of the construction site showing the formwork alignment jig installation process, and Figure 15 is an enlarged view of the area in Figure 14 as seen by the XV arrow. Figure 16 is a plan view of the construction site showing the formwork alignment jig installation process, and Figure 17 is an enlarged view of the area in Figure 16 as seen by the XVII arrow. Figure 18 is a cross-sectional view of the construction site showing the base pouring process, Figure 19 is a cross-sectional view of the construction site showing the inner formwork installation process, Figure 20 is a cross-sectional view of the construction site showing the strip foundation pouring process, and Figure 21 is a cross-sectional view of the construction site after the formwork dismantling process. In each figure, the horizontal direction, which is the longitudinal direction of the base 12 of the formwork alignment jig 1, is the X direction, the formwork alignment direction, which is the horizontal direction perpendicular to the X direction, is the Y direction, and the vertical direction is the X direction.

In the two-stage raft foundation construction method, the ground on the building site is first excavated to the specified size and depth and leveled, after which the lean concrete pouring process is carried out (see Figure 13). In the lean concrete pouring process, crushed stone 50 is laid and compacted, and then lean concrete 52 is poured on top. After the lean concrete 52 has cured, the positions of the reinforcing bars and formwork are marked out.

Next, the reinforcement bar placement process is carried out. In this process, reinforcing bars 3 are placed horizontally and vertically in the lean concrete 52 via spacer blocks 54 (see Figure 13). Here, the reinforcing bars 3 placed horizontally (X and Y directions) are referred to as horizontal bars 3Y, and those placed vertically (Z direction) are referred to as vertical bars 3T.

Next, the outer formwork installation process is carried out. In this process, formwork (hereinafter referred to as outer formwork SK) is erected along the outer perimeter of the site (see Figure 13). Specifically, multiple outer formwork SK are erected linearly and continuously in the longitudinal direction on the ground via formwork support members 58. Furthermore, rod-shaped support jigs 59 are attached to the outer perimeter of the outer formwork SK. Specifically, the upper end of the support jig 59 is fixed to the upper outer surface of the outer formwork SK, and it is positioned with an outward inclination as it extends downwards, with its lower end fixed to the ground.

Next, the formwork alignment jig installation process is performed. In this process, the formwork alignment jig 1 is attached to the reinforcing bar 3 at a position above the planned height BL of the base (see Figure 14). Figures 14 to 17 show the movable fixing device 20 of the formwork alignment jig 1 fixed to the vertical reinforcing bar 3T facing the outer formwork SK. When attaching the formwork alignment jig 1 to the vertical reinforcing bar 3T, the wing nuts 23 are loosened to expose the engagement holes 21c, 21c from the base 12. The jig is then inserted from the upper end of the vertical reinforcing bar 3T into the engagement holes 21c, 21c of the engagement member 21, or fitted into the side surface of the vertical reinforcing bar 3T through the circumferential openings of the engagement holes 21c, 21c. The vertical reinforcing bar 3T, which is positioned intersecting the horizontal reinforcing bar 3Y arranged in the Y direction, is less prone to bending. By attaching the formwork alignment jig 1 to the vertical reinforcing bar 3T, it becomes possible to securely fasten the inner surface of the outer formwork SK.

Next, as shown by the dashed lines in Figures 15 and 17, the jig body 10 is slid in the X direction to adjust it to a position where the outer formwork SK is aligned linearly and the distance L between the outer formwork SK and the vertical reinforcement bars 3T is a predetermined distance (for example, 40 mm or more). The wing nuts 23 that are screwed onto the bolts 22 are then tightened to secure it, thereby completing the fixing of the jig body 10 to the movable fixing device 20 and to the vertical reinforcement bars 3T. As a result, the outer formwork SK is pressed from the outside by the support jig 59 and from the inside by the formwork alignment jigs 1 attached at key points, thereby correcting any twisting between adjacent outer formwork SK. The formwork alignment jig 1 allows for free adjustment of the longitudinal relative position between the engaging member 21, which engages with the reinforcing bar 3, and the base 12, which has a flat plate portion 13 at one end. Therefore, even slight twists of a few millimeters in the outer formwork SK can be corrected, and the outer formwork SK can be precisely aligned in a straight line.

After the formwork and jig installation process, a base concrete pouring process is performed to form base section B (see Figure 18). In the base concrete pouring process, ready-mix concrete is poured up to the planned top height BL of the base section within the area enclosed by the outer formwork SK.

After the base concrete pouring process, and once the base concrete has hardened after the curing period, an inner formwork installation process is performed in which multiple formworks (hereinafter referred to as inner formwork UK) are erected opposite each other on the base portion B on the inner circumference side of the outer formwork SK (see Figure 19). During the inner formwork installation process, the formwork alignment jig 1 is also removed. The formwork alignment jig 1 can be removed from the reinforcing bars 3 (vertical reinforcement 3T) by grasping and loosening the wing nuts 23 with your fingers. Subsequently, after the inner formwork installation process, a strip foundation pouring process is performed in which strip foundation concrete is poured to form the strip foundation section N between the outer formwork SK and the inner formwork UK (see Figure 20).

After the curing period for the strip foundation concrete has elapsed and the concrete poured during the strip foundation pouring process has hardened, the final step is the formwork dismantling process, in which the outer formwork SK and inner formwork UK are removed. In the formwork dismantling process, all outer formwork SK, inner formwork UK, and support jigs 59 are removed, the ground is leveled, and the construction of the raft foundation is completed (see Figure 21).

<Summary of Embodiments>
As is clear from the above detailed description, the formwork alignment jig 1 according to this embodiment is a jig used to align formwork when forming a concrete foundation, by being attached between the outer formwork SK and the reinforcing bars 3 so as to press the inner surface of the outer formwork SK facing the reinforcing bars 3 , and comprises a jig body 10 having a base portion 12 having a predetermined length in the longitudinal direction and a flat plate portion 13 provided intersecting one end of the base portion 12 for pressing the inner surface of the outer formwork SK , and a movable fixing device 20 having an engagement hole 21c that engages with the reinforcing bars 3 and is provided so as to be able to adjust its relative position in the longitudinal direction with respect to the base portion 12, and a wing nut 23 as a fixing member that detachably fixes the engagement member 21 to the reinforcing bars 3.

In this configuration, the engaging member 21 of the movable fixing device 20 engages with the reinforcing bar 3 in the engaging hole 21c and is fixed to the reinforcing bar 3 while adjusting its relative position in the longitudinal direction with respect to the base 12 of the jig body 10. In this state, the flat plate portion 13 provided at one end of the base 12 presses against the inner surface of the outer formwork SK, which serves as the formwork. In other words, the flat plate portion 13 provided at one end of the base 12, whose relative position with respect to the engaging member 21 that engages with the reinforcing bar 3 is appropriately adjusted, presses against the inner surface of the outer formwork SK from the reinforcing bar 3 side. This corrects the twisting of the multiple outer formwork SK arranged in the width direction and appropriately maintains the distance L between the outer formwork SK and the reinforcing bar 3. Therefore, it is possible to linearly align the outer formwork SK while maintaining a predetermined distance between the outer formwork SK and the reinforcing bar 3.

Furthermore, the base portion 12 has an elongated hole 12a extending in the longitudinal direction, and the engaging member 21 has a bolt 22 as a protrusion that is inserted into the elongated hole 12a. The bolt 22 is inserted at any position in the longitudinal direction of the elongated hole 12a and fixed to the base portion 12 via a wing nut 23, which acts as a fixing member.

In this configuration, the bolt 22, which acts as a protrusion on the engaging member 21, is inserted into any position along the longitudinal direction of the elongated hole 12a provided in the base 12, and the engaging member 21 is fixed to the base 12 via the wing nut 23. Therefore, the engaging member 21 and the base 12 can be securely fixed while easily and appropriately adjusting their relative positions in the longitudinal direction.

Furthermore, the base portion 12 is a metal fitting with a U-shaped cross-section, and the engaging member 21 is a metal fitting with a U-shaped cross-section that is placed on top of the inside of the base portion 12. The engaging member 21 has a bolt 22 as a protrusion on the opposing surface of the base portion 12 that faces the surface forming the elongated hole 12a, and is inserted into the elongated hole 12a. A wing nut 23, acting as a fixing member, is screwed onto the portion of the bolt 22 protruding from the elongated hole 12a, thereby securing it to the base portion 12 and the reinforcing bar 3.

According to this configuration, the engaging member 21 is placed on top of the base 12, and a wing nut 23 is screwed onto the portion of the bolt 22 provided on the engaging member 21 that protrudes from the elongated hole 12a of the base 12. By fastening it at any position in the longitudinal direction, the engaging member 21 can be securely fixed to the base 12 and the reinforcing bar 3 with a simple configuration.

Furthermore, the flat plate portion 13 has a rubber sheet 14, which acts as an elastic material, provided on the surface opposite to the base portion 12.

With this configuration, the flat plate portion 13 can apply a surface-level pressing force to the outer formwork SK, while the elastic force of the rubber plate 14 ensures that it adheres securely to the inner surface of the outer formwork SK.

Furthermore, the engaging member 21 has a triangular portion 21d formed on a part of the inner circumference contour of the engaging hole 21c.

With this configuration, a triangular portion 21d is formed on a part of the inner contour of the engagement hole 21c, allowing multiple types of reinforcing bars 3 with different outer diameters to be stably engaged in the engagement hole 21c.

Furthermore, the engaging member 21 is formed in a C-shape, with a portion of the circumferential direction of the engaging hole 21c being open.

With this configuration, the side of the reinforcing bar 3 can be inserted through the opening formed in a part of the circumferential direction of the engagement hole 21c. Therefore, not only the vertically arranged reinforcing bars 3T, but also the horizontally arranged reinforcing bars 3Y, can be engaged with the engagement hole 21c at any desired position, allowing the formwork alignment jig 1 to be attached between the outer formwork SK and the reinforcing bars 3.

Here, an example of attaching the formwork alignment jig 1 to the horizontal reinforcement bar 3Y will be explained with reference to Figures 22 and 23. Figure 22 is an explanatory diagram showing the formwork alignment jig 1 attached to the horizontal reinforcement bar 3Y in a front view, and Figure 23 is an explanatory diagram showing the same in a plan view. As shown in Figures 22 and 23, the formwork alignment jig 1 is attached to the horizontal reinforcement bar 3Y with the wing nut 23 positioned above the base 12. The attachment position of the formwork alignment jig 1 to the horizontal reinforcement bar 3Y, which is arranged in the Y direction and facing the outer formwork SK, is preferably a location that is less prone to bending. For example, it is preferable to attach it near the intersection with the horizontal reinforcement bar 3Y arranged in the X direction. By attaching the formwork alignment jig 1 to a location on the horizontal reinforcement bar 3Y that is less prone to bending, it becomes possible to reliably press the inner surface of the outer formwork SK. Note that the formwork alignment jig 1 may also be attached to the horizontal reinforcement bar 3Y with the wing nut 23 facing below the base 12.

<First variation>
In the above embodiment, the base portion 12 and the flat plate portion 13 are formed from separate metal plates, and the flat plate portion 13 is welded to one end face in the longitudinal direction of the base portion 12 to integrate the two members. However, the embodiment is not limited to this. It is also possible to use a single metal plate beforehand and form the base portion 12 and the flat plate portion 13 by bending. For example, in the first modified example shown in Figure 24, the base portion 12 and the flat plate portion 13 are made from a single metal plate, and one end of the portion of the base portion 12 that is formed in a U-shape in cross-section is extended in a rectangular shape, and the upper and lower rectangular portions are bent at right angles upward and downward, respectively, to form the flat plate portions 13, 13. In this modified example, a pair of rubber plates 14, 14 are bonded to the upper and lower flat plate portions 13, 13 with adhesive.

<Second variation>
In the above embodiment, Figure 14, which shows the formwork alignment jig installation process, illustrates how the formwork alignment jig 1 is fixed near the upper end of the vertical reinforcement bar 3T, but this is not the only possible configuration. The attachment position of the formwork alignment jig 1 to the reinforcement bar 3 can be any position above the planned height BL of the top of the base section. For example, in the second modified example shown in Figure 25, the formwork alignment jig 1 is fixed to the vertical reinforcement bar 3T at a position between the first horizontal reinforcement bar 3Y from the top and the second horizontal reinforcement bar 3Y from the top.

<Other variations>
The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, in the above embodiment, the engaging member 21 is shown to be formed in a C-shape with a part of the circumferential direction of the engaging hole 21c being open, but the invention is not limited to this. For example, the engaging member 21 may be formed in a ring shape with the entire circumference of the engaging hole 21c closed.

Furthermore, in the above embodiment, to make it easier to confirm the distance L between the inner surface of the formwork and the reinforcing bars, numerical values representing the distance from one end of the jig body 10 in the longitudinal direction (the surface of the rubber plate 14 that contacts the inner surface of the formwork) may be displayed near each scale 12b engraved on the upper or lower surface of the base 12, such as 40 [mm], 45 [mm], 50 [mm], etc.

Furthermore, in the above embodiment, the rubber plate 14 is provided on the surface of the flat plate portion 13 opposite to the base portion 12. However, any elastic material with the necessary elasticity may be used instead of a rubber plate. For example, as the elastic material of the present invention, a sponge plate formed by foaming synthetic resin may be provided on the flat plate portion 13.

Furthermore, while the above embodiment shows an example where the base portion 12 and the flat plate portion 13, each formed from separate metal plates, are joined and integrated by welding, the two members may be integrated by methods other than welding. For example, a fixing allowance may be pre-extended on one or both of the base portion 12 and the flat plate portion 13, and the two members may be integrated by press forming on the fixing allowance.

1 Formwork alignment jig 10 Jig body 12 Base 12a Slotted hole 13 Flat plate 14 Rubber plate (elastic material)
20 Movable fixing device 21 Engaging member 21c Engaging hole 21d Triangular part 22 Bolt (protruding part)
23. Wing nut (fixing component, nut)
B Base section BL Planned height of the top of the base section N Strip foundation section SK Outer formwork UK Inner formwork

Claims (6)

A jig used to align formwork when forming a concrete foundation, which is attached between the formwork and the reinforcing bars so as to press against the inner surface of the formwork that faces the reinforcing bars ,
A jig body having a base having a predetermined length in the longitudinal direction, and a flat plate portion provided intersecting one end of the base for pressing the inner surface of the formwork ,
A movable fixing device having an engagement member having an engagement hole for engaging with the reinforcing bar and being provided so as to be able to adjust its relative position in the longitudinal direction with respect to the base, and a fixing member for removably fixing the engagement member to the reinforcing bar,
A formwork alignment jig equipped with the following features. The base portion has an elongated hole extending in the longitudinal direction,
The formwork alignment jig according to claim 1, wherein the engaging member has a projection that is inserted into the elongated hole, and the projection is fixed to the base via the fixing member when inserted into any position in the longitudinal direction of the elongated hole. The base is a metal fitting with a U-shaped cross-section.
The engaging member is a metal fitting with a U-shaped cross-section that is placed on top of the inside of the base,
The formwork alignment jig according to claim 2, wherein the engaging member is fixed to the base and the reinforcing bar by screwing a nut, which serves as the fixing member, onto the portion of the bolt that protrudes from the elongated hole and fastening it to the opposing surface of the base that faces the surface forming the elongated hole. The formwork alignment jig according to any one of claims 1 to 3, wherein the flat plate portion has an elastic body provided on the surface opposite to the base portion. The formwork alignment jig according to any one of claims 1 to 3, wherein the engaging member has a triangular portion formed on a part of the inner circumference contour of the engaging hole. The formwork alignment jig according to any one of claims 1 to 3, wherein the engaging member is formed in a C-shape with a portion of the circumferential direction of the engaging hole being open.