Fasteners for securing ground covering sheets

Abstract

The present invention provides a fastener that is easy to attach tools to the head, easy to drive into the ground, can stably secure the sheet to the ground, and does not increase the volume. [Solution] The fastener 1 for fixing a ground covering sheet according to the present invention consists of a pile portion 4 having a rotational axis that is driven into the ground, a head portion 2 that is integrally formed with the pile portion and exposed above ground, and a washer 10 that is passed from the tip of the pile portion and presses the sheet against the pile portion side of the head portion. The head portion has a thick shape with a regular hexagonal cross-section perpendicular to the rotational axis of the pile portion. The upper region of the pile portion from the middle of the longitudinal direction toward the head portion is cylindrical with a smooth surface, and the lower region toward the tip portion has screw threads that protrude from the surface in a spiral manner to the tip, and the lower region gradually tapers to a point, so that the pile portion advances into the ground by rotating the head portion.

Description

Technical Field

[0003]

[0001] The present invention relates to a structure of a fastener for fixing a sheet covering the ground, such as a weed control sheet, to the ground.

Background Art

[0002] There are many demands for covering the ground with sheets made of polymer resin films or synthetic fibers, such as weed control sheets, light-shielding sheets, agricultural multi-sheets that cover parts other than crops for the purpose of suppressing the growth of weeds by blocking sunlight, raising the ground temperature, and controlling weeds, curing sheets that cover the ground during civil engineering work, and disaster prevention sheets that prevent the spread of sediment during disasters. To fix these sheets to the ground, it is necessary to drive fixing fasteners into the ground at a plurality of ends of the sheet.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] The requirements for fasteners for fixing include: (1) that they can be driven into the ground quickly and without requiring much effort; (2) that the sheet can be securely fixed to the ground without easily coming off the fastener; and (3) that, once driven in, they are difficult to pull out by wind or other external forces for a long period of time. Conventionally, in order to satisfy condition (2), fasteners have been devised in which the length of the underground part of the fastener is made to a certain extent, and the metal is formed in a spiral shape rather than a straight line, and the head is rotated by hand or with a hammer as it is advanced into the ground (Patent Documents 1 and 2). Alternatively, fasteners have been devised in which a cylindrical support column driven into the ground is provided with screw threads and advanced by rotation, and the resistance to pulling out is increased by the screw threads (Patent Documents 3 and 4).

[0005] On the other hand, the heads of the fasteners that secure the sheet to the ground surface need to have a sufficiently large contact force between the head and the sheet in order to ensure sufficient pressure to hold the sheet down, so that the sheet does not easily come off the head due to wind or other external forces, as described in (3) above. For example, the above-ground portion of a metal column driven into the ground is bent at a right angle to provide a straight horizontal section, or the above-ground portion is bent spirally from the central axis of the metal column so that when the fastener is driven in, the spiral head bites into the ground to secure it (Patent Documents 1 and 2), or the head is shaped into a disc to increase the contact area with the sheet and increase the pressure on the ground (Patent Documents 3 and 4).

[0006] Regarding the ease of driving into the ground as described above (1), in the case of structures in which the head is formed by bending a metal column, as in Patent Documents 1 and 2, it is necessary to rotate the metal column directly by hand to advance it, which is problematic as it requires a lot of effort and time. In the case of a disc-shaped head, a method has been devised in which a hole is made horizontally in the head and a rod-shaped jig is passed through it and rotated by hand to bury it (Patent Document 3), or a structure in which a special cross groove is made in the head and it is buried using a screwdriver or impact driver (Patent Document 4).

[0007] While the method of burying the fastener using a screwdriver offers far superior workability compared to manual methods, it requires special processing to prevent the screwdriver from coming loose from the cross groove while the long support column is being advanced underground. This involves creating an entry hole or groove on the top surface of the screwdriver head to make it difficult for the screwdriver to detach (Patent Document 4). As a result, the manufacturing process for the fastener head increases, leading to higher manufacturing costs. [Means for solving the problem]

[0008] The fastener according to this invention has the shape of a hexagonal prism, with a head whose cross-section perpendicular to the central axis of the pile portion being a regular hexagon. The pile portion, which is driven into the ground, has a spirally arranged convex portion on its surface from the middle to the tip, forming a screw thread. Furthermore, a disc-shaped washer is detachably attached to the lower surface of the head of the hexagonal prism. To drive the fastener into the ground, a socket tool that fits the head of the hexagonal prism is used, and this is attached to a manual, electric screwdriver, or impact driver and rotated.

[0009] The fastener for fixing the ground covering sheet of this invention to the ground is configured as follows. The fastener consists of a pile section having a central axis of rotation that is driven into the ground, a head section that is exposed above ground and integrally formed with the pile section, and a washer that is passed through the tip of the pile section and presses against the sheet by contacting the lower surface of the head section. The head has a thick shape with a cross-section perpendicular to the rotational axis of the pile, forming a regular hexagon. Within the pile section, the upper region from the middle of the longitudinal direction towards the head is a cylindrical shape with a smooth surface, while the lower region towards the tip has screw threads protruding from the surface in a spiral pattern all the way to the tip. The lower section gradually tapers to a point at the tip, and the pile section is designed to penetrate the ground by rotating the head.

[0010] Within the diameter of the pile section, the diameter of the lower region where screw threads are provided may be smaller than the diameter of the upper region where screw threads are not provided, with an intermediate region in which the diameter decreases in a tapered manner in between.

[0011] The maximum outer diameter of the screw threads may be the same as the diameter of the upper region.

[0012] The ratio of the length of the lower region to the length of the upper region may be 2:1.

[0013] It is preferable that the outer diameter of the washer is 2 to 5 times the distance between the opposing faces of the regular hexagons on the head.

[0014] It is preferable that the material of the pile section and the top section be iron with a galvanized surface. [Effects of the Invention]

[0015] The sheet fastener of this invention can be easily installed in the ground using an electric rotary tool, requiring little effort. Furthermore, this configuration significantly increases the contact area between the fastener and the sheet using washers, allowing the sheet to be stably fixed to the ground without coming loose from the fastener.

[0016] Furthermore, since the washer's thickness can be made thinner than the head's thickness, even if its outer diameter is increased, it avoids the problem of increased volume during packaging compared to fasteners with an integrated sheet-holding section. In addition, the washer is a separate part from the integrated head / pile section and can be packaged separately. Therefore, when packaging and transporting multiple elongated fasteners together, the increase in volume due to the head can be avoided, which is advantageous in terms of transportation costs compared to conventional sheet fasteners. [Brief explanation of the drawing]

[0017] [Figure 1] This is an external view of the fastener for ground covering sheets according to the present invention. [Figure 2] The images show a side view of the fastener according to this invention (right), an enlarged top view and side view of the head of the fastener (upper left), and a side view and top view of the washer (lower left). [Modes for carrying out the invention]

[0018] Figure 1 shows an external view of the fastener for the ground covering sheet according to the present invention. The fastener 1 according to the present invention is composed of a straight cylindrical pile portion 4 having a rotation center axis, a regular hexagonal column-shaped head portion 2 integrally formed therewith, and a washer 10 inserted from the tip of the pile portion 4 and brought into contact with the lower surface of the head portion 2 for use.

[0019] Figure 2 shows a side view of the entire fastener 1 according to the present invention. Also, an enlarged top view and side view of the head portion 2 of the fastener 1 are shown in the upper left, and a side view and a plan view of the washer 10 are shown in the lower left, respectively. The pile portion 4 of the fastener 1 is composed of a cylindrical upper region 6 with a smooth surface and a lower region 8 with a thread 9 protruding convexly from the surface. The upper end of the upper region 6 is joined to the head portion 2. In the lower region 8, convex portions 9 forming the thread are continuously provided spirally up to the tip on the surface of the cylinder, and the tip is tapered with a gradually decreasing diameter and a sharp tip in order to reduce the resistance when advancing into the ground.

[0020] The diameter of the lower region 8 is tapered so as to gradually decrease from the diameter d of the upper region 6 in the intermediate region 7, and the maximum diameter of the male thread convex portion 9 of the lower region 8 is made the same as the diameter d of the upper region 6. In order to maintain the strength so that the pile portion 4 does not deform when advancing into the ground, the diameter d needs to be relatively large, but if it is too large, the resistance during advancement will increase. In this embodiment, d of 9 mm was used. By adopting the configuration as shown in Figure 2, it is possible to reduce the resistance during advancement while maintaining the strength of the pile portion 4.

[0021] The length L of the pile portion 4 is 100 to 500 mm and can be selected to any length according to the application. The length S of the lower region 8 is preferably about two-thirds of the length L of the pile portion 4, but other ratios may be used depending on the application. The material of the fastener 1 is preferably made of iron from the viewpoints of ensuring strength and cost, and it is desirable that the surface is plated with a material such as zinc in order to enhance the corrosion resistance in the ground. However, in the case of an application where the ground for fixing the sheet has a soft soil texture, a hard synthetic resin can also be used.

[0022] The shape of the head 2 is preferably a regular hexagonal column to accommodate socket wrenches and the like, which are used as power tools by manually attaching a spanner to the end, but it is not limited to this and other regular polygons are also acceptable. The thickness h of the head 2 can be any value as long as it is greater than or equal to a value that does not easily deform under the rotational force of the tool. In this embodiment, a thickness of 7 mm was used. The top surface of the head 2 in this embodiment is flat, but a minus-shaped or plus-shaped groove can be further provided on it to enable the use of electric screwdrivers and impact drivers as well.

[0023] The distance W between opposing faces of the regular hexagons of head 2 can be any value as long as it is greater than d. In this example, a value of 17 mm was used. Increasing the distance W between opposing faces reduces the force required to rotate the head, thus reducing the effort required for rotation compared to, for example, rotating a Phillips head hole with a screwdriver. Furthermore, since many fasteners are used to fix ground covering sheets when installing multiple sheets at once, increasing the outer diameter of head 2 increases the volume and weight of the fasteners. Therefore, if W is made too large, a disadvantage arises in that the overall volume and weight become large when multiple fasteners are packaged together.

[0024] When fixing the sheet to the ground, the contact area with the sheet is small if only the lateral extension of the head 2 is used, so the sheet may easily come off the fastener 1 due to external forces such as wind. However, increasing W to solve this problem would lead to the aforementioned volume and weight issues, so instead, a washer 10 is used with an outer diameter R that is larger than the distance W between the opposing surfaces of the head 2, and a through hole 12 in the center with an inner diameter r greater than d. The washer is inserted from the tip of the stake 4 until it contacts the lower surface of the head 2, thereby contacting and pressing the sheet surface. The washer can be disc-shaped, and its outer diameter R can be any value larger than the maximum outer diameter of the regular hexagon of the head 2. Increasing it will improve the contact area with the ground. However, if it is too large, it may impair the original purpose of the sheet and cause problems such as increased material costs. Therefore, R is preferably about 2 to 5 times W. [Explanation of Symbols]

[0025] 1. Sheet fastener 2 heads 4 Pile part 6 Upper area 7 Intermediate area 8 Lower area 9. Screw thread (protruding part) 10 washers 12 Passing hole

Claims

1. A fastener for securing a sheet covering the ground to the ground, The fastener consists of a pile portion having a rotational central axis that is driven into the ground, a head portion that is exposed above ground and integrally formed with the pile portion, and a washer that is passed through the tip of the pile portion and presses against the sheet by contacting the lower surface of the head. The head portion has a thick shape with a cross-section perpendicular to the rotational center axis of the pile portion, which is a regular hexagon. Of the aforementioned pile portion, the upper region from the middle of the longitudinal direction towards the head is cylindrical with a smooth surface, and the lower region towards the tip has screw threads protruding from the surface in a spiral pattern up to the tip. The lower region gradually tapers to a point at the tip, and the pile portion is designed to advance into the ground by rotating the head. Fastener.

2. The fastener according to claim 1, wherein, of the diameter of the pile portion, the diameter of the lower region having screw threads is smaller than the diameter of the upper region having screw threads, with an intermediate region in which the diameter decreases in a tapered manner in between.

3. The fastener according to claim 2, wherein the maximum outer diameter of the screw threads is the same as the diameter of the upper region.

4. The fastener according to any one of claims 1 to 3, wherein the ratio of the length of the lower region to the length of the upper region is 2:

1.

5. The fastener according to claim 1, wherein the outer diameter of the washer is 2 to 5 times the distance between the opposing faces of the regular hexagon of the head.

6. The fastener according to claim 1, wherein the material of the pile portion and the head portion is iron with a zinc-plated surface.

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