Repairing waterproof sheet fixture

Abstract

To provide a repairing waterproof sheet fixture having higher cross-sectional secondary moment and higher strength than before.SOLUTION: A tabular repairing waterproof sheet fixture 3 is overlaid on an existing waterproof sheet fixture disposed on a waterproof substrate and allows a waterproof sheet 2 to be fixed on the front surface. The repairing waterproof sheet fixture has a center groove-like part 32 located around a center point C3, and an outside part 33 located on the outside of the center groove-like part 32 in a plan view. The outside part 33 has a groove-like outside groove-like part 33a spaced away from the center groove-like part 32, and an outside through hole 33b into which a fixing member 11 for fixing the waterproof sheet 2 to the existing waterproof sheet fixture is inserted.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a renovation tarpaulin fastener. [Background technology]

[0002] The waterproof sheet fixing device described in Patent Document 1 comprises an insertion hole through which a fastener for fixing the waterproof sheet fixing device to a base is inserted, a raised portion that is raised from the insertion hole toward the outer periphery, a groove portion that is formed further toward the outer periphery from the raised portion and surrounds the insertion hole, and a fixing plate that is positioned outer periphery of the groove and to which the waterproof sheet is fixed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-187338 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the waterproof sheet fastener described in Patent Document 1, no groove is formed in the fastening plate located on the outer circumferential direction of the groove.

[0005] Here, the waterproof structure with the waterproof sheet laid is replaced periodically to prevent the deterioration of watertightness over time. When renovating an existing waterproof structure, in order to make the renovation work more efficient, a new waterproof sheet is sometimes laid over the existing waterproof sheet without removing it from the waterproof base.

[0006] Depending on the condition and type of the waterproof base, the waterproof sheet fixing device for renovation used in such renovation work may not be fixed directly to the waterproof base, but may be layered on an existing waterproof sheet fixing device and fixed. The waterproof sheet fixing device for renovation layered on the existing waterproof sheet fixing device is located at a higher position than the waterproof sheet fixing device fixed to the waterproof base. As a result, when a strong wind blows, the waterproof sheet fixing device for renovation is likely to be subjected to a force that blows the waterproof sheet upward. Therefore, it is desirable to increase the strength of the waterproof sheet fixing device for renovation by making the second moment of area higher than that of the waterproof sheet fixing device fixed to the waterproof base.

[0007] An object of the present invention is to provide a waterproof sheet fixing device for renovation that has a higher moment of area and higher strength than conventional devices. [Means for solving the problem]

[0008] As a means for solving the above-mentioned problems, the renovation waterproof sheet fixing device of the present invention is a plate-shaped renovation waterproof sheet fixing device that is placed on top of an existing waterproof sheet fixing device provided on a waterproof base and has a waterproof sheet fixed to its front surface, and is characterized in that it has a groove-shaped central groove-shaped portion located around a central point and an outer portion located outside the central groove-shaped portion in a planar view, and the outer portion has a groove-shaped outer groove-shaped portion spaced apart from the central groove-shaped portion and an outer through hole through which a fixing member for fixing the waterproof sheet to the existing waterproof sheet fixing device is inserted.

[0009] Through the ingenuity of the inventors, it was discovered that the waterproof sheet fixing device for renovation of the present invention has a high moment of area and high strength by providing an outer groove-like portion. With this configuration, the outer groove-like portion, which is a groove-like portion separated from the central groove-like portion, makes the fixing device for renovation waterproof sheet of the present invention stronger than conventional fixing devices.

[0010] In the present invention, it is preferable that a plurality of the outer groove portions are arranged at equal intervals in the circumferential direction.

[0011] The waterproof sheet is not fixed to the areas where the outer groove-shaped areas are located. According to this configuration, the areas where the waterproof sheet is not fixed are located at equal intervals in the circumferential direction, so that the waterproof sheet is evenly fixed to the renovation waterproof sheet.

[0012] In the present invention, it is preferable that the number of the outer groove portions is an odd number, and that the outer groove portions extend in a direction away from the central point.

[0013] According to this configuration, the two outer groove portions are not arranged on the same line in the radial direction, which increases the second moment of area and the strength compared to a configuration in which the two outer groove portions are arranged on the same line in the radial direction.

[0014] Furthermore, through ingenuity of the inventors, it was found that a configuration in which the outer groove-like portion extends in a direction away from the center point has a higher moment of area and is stronger than a configuration in which the outer groove-like portion extends in a direction perpendicular to the radial direction or a configuration in which the outer groove-like portion extends at an angle to the circumferential direction of the outer portion. With this configuration, the outer groove-like portion extending in a direction away from the center point provides greater strength than conventional configurations.

[0015] In the present invention, it is preferable that the pair of outer through holes are located symmetrically with respect to the central point.

[0016] With this configuration, compared to a configuration in which the two outer through holes are positioned offset to one side from the center point, the points that are fixed to the existing waterproof sheet fastener are even, and the renovation waterproof sheet fastener is stably supported by the existing waterproof sheet fastener.

[0017] In the present invention, it is preferable that the radial straight-line distance from the outer end of the central groove-shaped portion to the inner end of the outer groove-shaped portion is smaller than the radial straight-line distance from the outer end of the outer groove-shaped portion to the outer edge of the outer portion.

[0018] When a strong wind blows the waterproof sheet upward, a large force is applied to the connection between the outer edge of the outer portion and the waterproof sheet. With this configuration, compared to a configuration in which the linear distance in the radial direction from the outer end of the central groove portion to the inner end of the outer groove portion is equal to or greater than the linear distance in the radial direction from the outer end of the outer groove portion to the outer edge of the outer portion, the area where the waterproof sheet is fixed is larger from the outer end of the outer groove portion to the outer edge of the outer portion, making the waterproof sheet less likely to peel off. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a plan view showing a waterproof sheet fixing device for renovation. [Diagram 2] FIG. 2 is a cross-sectional view taken along the line II-II in FIG. [Diagram 3] 1 is a flowchart showing a renovation method using a renovation waterproof sheet fastener. [Figure 4] This is a drawing showing a method for verifying the strength of a waterproof sheet fixing device for renovation. [Diagram 5] 13 is a diagram showing a verification result. [Figure 6] 13 is a diagram showing a verification result. [Figure 7] FIG. 11 is a plan view showing another example of a waterproof sheet fixing device for renovation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The waterproof sheet fixing device for renovation according to the present invention will be described below with reference to the drawings. In the following description, the direction of the arrow U in the drawings will be referred to as the "upper side" and the direction of the arrow D will be referred to as the "lower side".

[0021] The renovation waterproof sheet fastener 3 according to the present invention is used when renovating a waterproof structure that has been waterproofed with a waterproof sheet.

[0022] The cross-sectional line II-II shown in FIG. 1 extends in a straight line from the upper side of the paper to the center point C3, bends clockwise at the center point C3, and extends in a straight line from the center point C3 toward the lower left side of the paper.

[0023] As shown in Figures 1 and 2, the renovation waterproof sheet fastener 3 is plate-shaped and is placed on an existing waterproof sheet fastener 13 that fastens an existing waterproof sheet 12 to a waterproof base 1. The renovation waterproof sheet fastener 3 is fixed to the existing waterproof sheet fastener 13, and the waterproof sheet 2 is fixed to the front surface. This makes it possible to lay the waterproof sheet 2 on top of the existing waterproof sheet 12 without removing the existing waterproof sheet 12 from the waterproof base 1 when renovating an existing waterproof structure.

[0024] Here, the "existing waterproof sheet" refers to a waterproof sheet that has already been laid when renovating a waterproof structure, and on whose front surface the waterproof sheet 2 is laid. The "existing waterproof sheet fastener" refers to a plate-shaped waterproof sheet fastener on whose front surface the existing waterproof sheet 12 is fixed.

[0025] In this embodiment, the existing waterproof sheet fastener 13 has a central through-hole 13a located at the center point. The existing waterproof sheet fastener 13 is fixed to the waterproof substrate 1 by a tapping screw 14 inserted into the central through-hole 13a. In other words, the existing waterproof sheet 12 is fixed to the waterproof substrate 1 by the existing waterproof sheet fastener 13. However, the existing waterproof sheet fastener 13 may be fixed to the waterproof substrate 1 by an anchor bolt depending on the type of the waterproof substrate 1.

[0026] The waterproof sheet 2 and the existing waterproof sheet 12 are sheet-like members made of a resin material. Specifically, the waterproof sheet 2 is a vinyl chloride-based waterproof sheet. The resin material is not limited to this, and may be other resins, such as polyolefin-based resins, ethylene-vinyl acetate copolymers, etc., and these may also be used in combination. Furthermore, the waterproof sheet 2 and the existing waterproof sheet 12 may be sheet-like members made of rubber.

[0027] The waterproof foundation 1 is a waterproof structure that is waterproofed by a waterproof sheet 2. In this embodiment, the waterproof foundation 1 is the rooftop framework of a building. Specifically, the waterproof foundation 1 has a plate-shaped metal roof 1a that is corrugated in a vertical cross-sectional view with repeated peaks and valleys, and a heat insulating material 1b that is laid on top of the metal roof 1a. The waterproof foundation 1 may have other forms. For example, the waterproof foundation 1 may be a framework made of wood, concrete, or a combination of metal and concrete. Furthermore, the surface portion of the waterproof foundation 1 may be a vertical surface such as a vertical wall or an inclined surface in addition to a horizontal surface.

[0028] 2, a line CH is an imaginary line passing through the center of the renovation waterproof sheet fixing device 3. A point C3 located on the line CH indicates the center point of the renovation waterproof sheet fixing device 3.

[0029] 1 and 2, the waterproof sheet fixing device for renovation 3 is a disk-shaped member with a diameter of about 50 to 100 mm. However, the waterproof sheet fixing device for renovation 3 may have other shapes. For example, the waterproof sheet fixing device for renovation 3 may be a square or polygonal shape in a plan view.

[0030] The waterproof sheet fixing device for renovation 3 comprises a groove-shaped central groove-like portion 32 located around a central point C3, a central portion 31 surrounded by the central groove-like portion 32, and an outer portion 33 located outside the central groove-like portion 32 in a plan view. The waterproof sheet fixing device for renovation 3 of this embodiment does not have a through hole at the central point C3 through which a tapping screw is inserted.

[0031] A layer H for fixing the waterproof sheet 2 is formed on the front surface of the renovation waterproof sheet fixing device 3. The waterproof sheet 2 is fixed to the front surfaces of the central region 31 and the outer regions 33 by this layer H. Specifically, the waterproof sheet 2 is fixed to the renovation waterproof sheet fixing device 3 by heat fusion or solvent fusion, or the like.

[0032] [Central groove-like area] The central groove-shaped region 32 is a region formed in a concave shape. In other words, the central groove-shaped region 32 is a recess. The bottom of the central groove-shaped region 32 is located closer to the waterproof base 1 side than the front surface of the outer region 33. The central region 31 is surrounded by a series of recesses connecting the longitudinal ends of the central groove-shaped region 32. Specifically, the central groove-shaped region 32 surrounds the central region 31 so as to form a polygonal shape.

[0033] [Central part] As shown in Figures 1 and 2, the central portion 31 is located around the central point C3. The central portion 31 is flat. The central portion 31 extends parallel to the outer portion 33. In this embodiment, the central portion 31 and the outer portion 33 are flush with each other. This is not a limitation, and the central portion 31 does not have to be flush with the outer portion 33. For example, the central portion 31 may be located closer to the waterproof base 1 than the front surface of the outer portion 33, or may protrude toward the front side than the front surface of the outer portion 33.

[0034] The central portion 31 has a polygonal shape in a planar view. The number of interior angles of the central portion 31 is preferably 4 to 8 in a planar view. In this embodiment, the central portion 31 has a pentagonal shape with 5 interior angles in a planar view. However, the central portion 31 may have another shape. For example, the central portion 31 may have a circular shape in a planar view.

[0035] [Outer part] 1 and 2, the outer portion 33 is positioned around the central groove portion 32. The outer portion 33 is flat. The outer portion 33 has an outer groove portion 33a which is a groove separated from the central groove portion 32, and an outer through hole 33b through which a rivet 11 (corresponding to the fixing member of the present invention) for fixing the waterproof sheet 2 to an existing waterproof sheet fixing device 13 is inserted.

[0036] The outer portion 33 is positioned so as to overlap with the outer portion 13c of the existing waterproof sheet fastener 13. In other words, the outer through-hole 33b is arranged so as to overlap with the outer portion 13c of the existing waterproof sheet fastener 13. This makes it easier for the rivet 11 inserted into the outer through-hole 33b to be fixed to the outer portion 13c of the existing flat waterproof sheet fastener 13.

[0037] [Outer groove-like part] The outer groove portion 33a is a portion formed in a concave shape. In other words, the outer groove portion 33a is a recess. The bottom of the outer groove portion 33a is located closer to the waterproof base 1 than the front surface of the outer portion 33. The longitudinal size of the outer groove portion 33a is 4.8 to 14.8 mm.

[0038] The number, arrangement, and orientation of the outer groove-like portions 33a are arbitrary. In this embodiment, the number of the outer groove-like portions 33a is multiple. The outer groove-like portions 33a are adjacent to the vertices of the polygonal central portion 31 on the radially outer side. In other words, the outer groove-like portions 33a are arranged on a straight line passing through the vertices of the polygonal central portion 31 and the central point C3. Furthermore, the multiple outer groove-like portions 33a are arranged at equal intervals in the circumferential direction. The outer groove-like portions 33a extend in a direction away from the central point C3.

[0039] As shown in FIG. 1, the linear distance L1 in the radial direction from the outer end of the central groove portion 32 to the inner end of the outer groove portion 33a is smaller than the linear distance L2 in the radial direction from the outer end of the outer groove portion 33a to the outer edge of the outer portion 33. When a strong wind blows the waterproof sheet 2 upward, a large force is applied to the connection between the outer edge of the outer portion 33 and the waterproof sheet 2. By arranging the outer groove portion 33a closer to the central point C3, the area from the outer end of the outer groove portion 33a to the outer edge of the outer portion 33 is larger in the outer portion 33 than in a configuration in which the outer groove portion 33a is arranged closer to the outer edge of the outer portion 33, so that the waterproof sheet 2 is less likely to peel off from the outer portion 33.

[0040] [Outer through hole] 1, the pair of outer through-holes 33b are located symmetrically with respect to the center point C3. As a result, compared to a configuration in which the pair of outer through-holes 33b are located only on one side of the center point C3, the portions fixed to the existing waterproof sheet fastener 13 are uniform, so that the renovation waterproof sheet fastener 3 is stably supported by the existing waterproof sheet fastener 13.

[0041] Next, a method for renovating a waterproof structure using the renovation waterproof sheet fastener 3 will be described with reference to the flowchart in Fig. 3. Note that the order of the steps described below may be changed or multiple steps may be performed simultaneously, as long as no contradiction occurs.

[0042] The waterproof sheet fixing tool 3 for renovation is placed at a position where it overlaps with the existing waterproof sheet fixing tool 13 (step S01). Specifically, as shown in FIG. 2, the waterproof sheet fixing tool 3 for renovation is placed at a position where the center point of the existing waterproof sheet fixing tool 13 and the center point C3 of the waterproof sheet fixing tool 3 for renovation overlap. When the central groove-like portion 13b of the existing waterproof sheet fixing tool 13 surrounds the center point in a circular shape, the central groove-like portion 32 of this embodiment surrounds the center point C3 in a pentagonal shape, so that the central groove-like portion 32 has a different shape in a plan view from the central groove-like portion 13b of the existing waterproof sheet fixing tool 13. This makes it difficult for a part of the central groove-like portion 32 to fit into the central groove-like portion 13b of the existing waterproof sheet fixing tool 13. Therefore, the posture of the waterproof sheet fixing tool 3 for renovation is unlikely to become slanted, and the waterproof sheet fixing tool 3 for renovation is stably supported by the existing waterproof sheet fixing tool 13.

[0043] Next, the waterproof sheet fastener 3 for renovation is fixed to the existing waterproof sheet fastener 13 (step S02). Specifically, as shown in Fig. 2, a rivet 11 is inserted into the outer through-hole 33b of the waterproof sheet fastener 3 for renovation, and the waterproof sheet fastener 3 for renovation is fixed to the outer portion 13c of the existing waterproof sheet fastener 13 by the rivet 11. However, the waterproof sheet fastener 3 for renovation may be fixed to the existing waterproof sheet fastener 13 by other fixing members such as tapping screws.

[0044] Next, the waterproof sheet 2 is laid over the existing waterproof sheet 12 and the renovation waterproof sheet fixing device 3 (step S03). The waterproof sheet 2 is fixed to the front surface of the renovation waterproof sheet fixing device 3 (step S04). In this embodiment, the layer H made of thermoplastic synthetic resin of the renovation waterproof sheet fixing device 3 is melted by an electromagnetic induction heater to fuse the waterproof sheet 2 to the front surface of the renovation waterproof sheet fixing device 3. However, the waterproof sheet 2 may be fused to the front surface of the renovation waterproof sheet fixing device 3 by the layer H made of a solvent.

[0045] [Verification of the strength of waterproof sheet fixing devices for repairs using outer grooved sections] A simulation was used to investigate the relationship between the shape of the outer groove-like portion 33a and the strength of the waterproof sheet fixing device for renovation 3. The steel material of the waterproof sheet fixing device for renovation 3 was SUS430. The thickness of the steel material was set to 0.6 mm.

[0046] As shown in Fig. 4, a load was applied to the pair of outer through-holes 33b in the direction of gravity with the back surface of the outer edge of the renovation waterproof sheet fixing device 3 fixed to a fixing part located below the renovation waterproof sheet fixing device 3. In this state, the displacement (second moment of area) of the renovation waterproof sheet fixing device 3 was calculated by simulation.

[0047] As shown in FIG. 5, the load applied to the renovation waterproof sheet fixing device 3 was changed to 200N, 400N, 600N, 800N, 1000N, 1200N and 1400N.

[0048] In addition, 12 types of samples of the renovation waterproof sheet fasteners 3 were prepared, in which the number of outer groove portions 33a and the longitudinal size of the outer groove portions 33a were changed.

[0049] The number of outer groove portions 33a in each sample is 1 for sample A, 2 for sample B, 3 for sample C, 4 for sample D, 5 for sample E, and 6 for sample F. In addition, a sample with zero outer groove portions 33a (without ribs) was prepared as a comparison. In all samples, the outer groove portions 33a extend in a direction away from the center. Also, the shape of the center portion 31 in plan view is circular. Furthermore, the outer groove portions 33a of sample BF are arranged at equal intervals in the circumferential direction.

[0050] 5, the longitudinal size of the outer groove portion 33a is 14.8 mm in samples A, B, and F. Samples C, D, and E were prepared by changing the longitudinal size of the outer groove portion 33a to 4.8 mm, 9.8 mm, and 14.8 mm, respectively.

[0051] Compared with the sample with 0 outer groove-shaped portions 33a (without ribs), the amount of displacement was smaller in all 12 types of samples. Therefore, it was recognized that the outer groove-shaped portions 33a affect the strength of the waterproof sheet fixing device 3 for renovation. In particular, it was recognized that the amount of displacement of sample C (with 3 outer groove-shaped portions 33a) and E (with 5 outer groove-shaped portions 33a) tended to be smaller than that of the other samples. In samples C and E, the two outer groove-shaped portions 33a are not arranged in a straight line. On the other hand, in samples B (with 2 outer groove-shaped portions 33a), D (with 4 outer groove-shaped portions 33a), and F (with 6 outer groove-shaped portions 33a), at least two outer groove-shaped portions 33a are arranged in a straight line. Therefore, when there are multiple outer groove-shaped portions 33a, it is preferable to arrange an odd number of outer groove-shaped portions 33a at equal intervals in the circumferential direction.

[0052] On the other hand, little difference in the amount of displacement due to the longitudinal size of the outer groove portion 33a was observed. In other words, the longitudinal size of the outer groove portion 33a is preferably 4.8 mm to 14.8 mm. Here, the smaller the longitudinal size of the outer groove portion 33a, the larger the fixing area between the renovation waterproof sheet fixing device 3 and the waterproof sheet 2. Therefore, it is particularly preferable that the longitudinal size of the outer groove portion 33a is 4.8 mm.

[0053] Next, as shown in FIG. 6, the change in the amount of displacement due to the difference in the shape of the central portion 31 in a plan view and the orientation of the outer groove-like portion 33a was examined. Twelve types of sample GR were prepared. FIG. 6 shows the shape of the central portion 31 of sample GR in a plan view and the orientation of the outer groove-like portion 33a in a plan view. Specifically, in FIG. 6, the central portion 31 and the central groove-like portion 32 are shown by double circles or double pentagons surrounding the center of the waterproof sheet fixing device 3 for renovation. Also, the outer groove-like portion 33a is shown by multiple rectangles arranged in the circumferential direction. In these samples GR, the longitudinal size of the outer groove-like portion 33a is 4.8 mm.

[0054] Regarding the shape of the central portion 31 in plan view, the shape of the central portion 31 in sample GK is circular in plan view. The shape of the central portion 31 in sample LR is pentagonal in plan view. As a result, as shown in FIG. 6, it was found that the amount of displacement of samples L, M, O, P, Q, and R, except for sample N, tended to be smaller than the amount of displacement of GK. In sample N, the outer groove portion 33a is disposed at a position where it contacts the central groove portion 32. Therefore, it is preferable that the shape of the central portion 31 in plan view is pentagonal rather than circular. Furthermore, when the central portion 31 is pentagonal in plan view, it is preferable that the outer groove portion 33a is disposed at a position separated from the central groove portion 32.

[0055] In addition, regarding the orientation of the outer groove portion 33a, in samples H, I, J, M, N, O, and Q, the outer groove portion 33a extends in a direction away from the center point C3. In samples K, P, and R, the outer groove portion 33a extends in a direction perpendicular to the radial direction of the outer portion 33. In samples G and L, the outer groove portion 33a extends in a tilted circumferential direction of the outer portion 33. As a result, as shown in FIG. 6, the amount of displacement of samples J, M, O, P, Q, and R tended to be small. Therefore, it is preferable that the outer groove portion 33a extends in a direction away from the center point C3 or in a direction perpendicular to the radial direction of the outer portion 33. Among them, it was found that the amount of displacement of samples M and O was particularly small. Therefore, when the central portion 31 is pentagonal in a plan view, it is particularly preferable that the outer groove portion 33a extends in a direction away from the center point C3.

[0056] From the above results, it was found that the shape of the central portion 31 in plan view and the orientation of the outer groove-like portions 33a influence the strength of the renovation waterproof sheet fastener 3.

[0057] [Another embodiment] The present invention is not limited to the above-described embodiment. For example, the following other embodiments may be used. In the following other embodiments, the same components as those in the above-described embodiment are denoted by the same numbers and symbols as those in the above-described embodiment.

[0058] [1] In the above embodiment, the renovation waterproof sheet fixing device 3 has the central portion 31. However, the renovation waterproof sheet fixing device 3 does not have to have the central portion 31. Specifically, the entire area on the central point C3 side of the outer portions 33 may be the central groove-like portion 32. In other words, the bottom surface of the central groove-like portion 32 in a plan view may be a polygon with four or more and eight or less interior angles.

[0059] [2] As shown in Fig. 7, the outer groove portions 33a may extend at an angle in the circumferential direction of the outer portion 33. In addition, when the central portion 31 is pentagonal, the outer groove portions 33a do not have to be adjacent to the vertices of the polygonal central portion 31 on the radially outer side.

[0060] [3] The outer groove portion 33 a may extend in a direction perpendicular to the radial direction of the outer portion 33 .

[0061] [4] As shown in Fig. 7, the interval between some of the outer groove portions 33a may be different from the interval between the other outer groove portions 33a. In other words, the outer groove portions 33a do not have to be arranged at equal intervals in the circumferential direction.

[0062] [5] The outer through-holes 33b do not have to be a pair. For example, the outer portion 33 may have one outer through-hole 33b, or three or more outer through-holes 33b.

[0063] [6] The distance L1 may be the same as the distance L2, or the distance L1 may be greater than the distance L2.

[0064] [7] In the above-described embodiment, the central region 31 is surrounded by a series of recesses connecting the longitudinal ends of the central groove-like regions 32. However, the present invention is not limited to this, and the central region 31 may be surrounded by a plurality of central groove-like regions 32 spaced apart in the circumferential direction, instead of a series of recesses connecting the longitudinal ends of the central groove-like regions 32.

[0065] [8] In the above-described embodiment, the waterproof sheet fixing device for renovation 3 of the present embodiment does not have a through hole at the center point C3 through which a tapping screw, an anchor bolt, etc. are inserted. However, the waterproof sheet fixing device for renovation 3 may have a through hole at the center point C3 through which a tapping screw, an anchor bolt, etc. are inserted.

[0066] [9] The configurations disclosed in the above embodiments (including other embodiments, the same applies below) may be applied in combination with configurations disclosed in other embodiments, unless a contradiction arises. In addition, the embodiments disclosed in this specification are merely examples, and the embodiments of the present invention are not limited thereto. They may be modified as appropriate within the scope of the purpose of the present invention. [Industrial Applicability]

[0067] The present invention is applicable to retrofit tarpaulin fasteners. [Explanation of symbols]

[0068] 1: Waterproof base 2: Waterproof sheet 3: Fixing device for waterproof sheet for renovation 32: Central groove area 33:Outer part 33a: Lateral groove-like part 33b: Outer through hole 11: Rivet (fixing member) 13: Existing waterproof sheet fixing device C3: Center point L1: distance L2: distance

Claims

1. A plate-shaped waterproof sheet fastener for renovation is placed on an existing waterproof sheet fastener provided on a waterproof base, and a waterproof sheet is fixed to the front surface. A central groove-like portion having a groove shape located around a central point; and an outer portion located outside the central groove portion in a plan view, The outer portion is a renovation waterproof sheet fixing device having a groove-shaped outer groove portion spaced apart from the central groove portion, and an outer through hole through which a fixing member for fixing the waterproof sheet to the existing waterproof sheet fixing device is inserted.

2. The waterproof sheet fixing device for renovation according to claim 1 , wherein a plurality of said outer groove-like portions are arranged at equal intervals in the circumferential direction.

3. the number of outer groove portions is an odd number, 3. The renovation tarpaulin fastener of claim 2, wherein said outer grooves extend in a direction away from said central point.

4. The waterproof sheet fixing device for renovation according to claim 1 , wherein a pair of the outer through holes are located symmetrically with respect to the central point.

5. A waterproof sheet fixing device for renovation as described in claim 1, wherein the radial straight-line distance from the outer end of the central groove-shaped portion to the inner end of the outer groove-shaped portion is smaller than the radial straight-line distance from the outer end of the outer groove-shaped portion to the outer edge of the outer portion.

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