JP7239771B2 - pegs for tent - Google Patents

Description

The present invention relates to the structure of tent pegs (hereinafter also simply referred to as "pegs") for fixing ropes of tents and tarps to the ground.

Tent pegs are generally made of metal. Depending on the size of the tent, more than ten pegs may be required at a time, in which case the total weight of the metal pegs exceeds 2 kg, and when camping, there are many luggage such as food. Combined with that, transportation is surprisingly difficult.

Therefore, in order to meet the need to reduce the weight of camping luggage as much as possible, resin tent pegs aimed at weight reduction are used (see, for example, Patent Documents 1 and 2).
Also known is a peg in which an alloy peg cap and an alloy peg tip are joined to a peg body manufactured by cutting a sheet made of a carbon fiber material (see Patent Document 3, for example).

Japanese Utility Model Publication No. 51-739 JP-A-10-205174 JP 2020-118019 A

The resin-made tent pegs aimed at weight reduction have a problem in that the strength is low, and the pegs as a whole tend to bend when driven into hard ground, making driving difficult.
In addition, many of them are made of a single resin, and when the rope is hooked and pulled, there is a problem that if a large load is applied to the rope, it will be greatly bent and broken.
The peg using the carbon fiber material needs to join the peg cap and the peg tip made of an alloy, which requires a separate step of joining the peg cap and the peg tip, and the trouble of sorting when discarded.

An object of the present invention is to develop a lightweight, high-strength resin tent peg that can be provided at a low price.

In order to solve the above-mentioned problems, the present inventors have earnestly studied how to reduce the weight and increase the strength of pegs for tents, and have completed the present invention.

That is, the gist of the present invention is as follows.
[1] A peg for a tent, characterized by being made of a material in which a fibrous material is contained in a thermoplastic resin.
[2] In a cross section cut at the axis in the axial direction of the peg,
As measured by the pulp-debris measurement method specified in JIS P 8208,
The tent peg according to [1] above, wherein there is no empty wall with a cross-sectional area larger than 0.20 mm ² within 20 mm from the tip of the peg.
[3] The tent peg according to [1] or [2] above, wherein the fibrous material is carbon fiber.
[4] The tent peg according to any one of [1] to [3], wherein the thermoplastic resin is a polyamide resin.
[5] The tent peg according to [4], which is made of a polyamide-based resin having an aromatic ring.
[6] The tent peg according to any one of [1] to [5], which has a flexural modulus of 10000 N/mm ² or more.
[7] The tent peg according to any one of [1] to [6] above, wherein the peg has a pull-out force of 9 kgf or more when a pull-out test is performed in the following test system.
(Test system) A peg is pierced into the hard ground so that its axial direction forms a crossing angle of 60° with respect to the ground surface. Wrap the end of the wire around the top of the peg, pull the other end of the wire in the direction perpendicular to the axial direction of the peg, measure the load applied to the peg, and when the peg comes off the ground, the peg breaks or The load at the time of breakage is defined as the pull-out force of the peg.

According to the present invention, it is possible to provide a tent peg that is lightweight, has a high flexural modulus, and is inexpensive.

1 is an external view of a tent peg according to one embodiment of the present invention; FIG. FIG. 2 is a diagram showing a schematic test system of a peg bending test performed in Examples. 1 is a diagram showing a schematic test system of a peg pull-out test performed in Examples. FIG. It is the top view and side view of the tent which showed the relationship of the force which acts on the wind pressure which a tent receives when a tent is put up, and a peg. 10 is a cross-sectional photograph of cutting three pegs in Example 9. FIG. FIG. 6 is a diagram that replicates the photograph of FIG. 5 ; FIG. 10 is a cross-sectional photograph of cutting three pegs in Example 10. FIG. FIG. 8 is a diagram that replicates the photograph of FIG. 7 ;

Preferred embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the gist thereof.

As described above, the tent peg of the present invention is made of a thermoplastic resin containing a fibrous material.
Tent pegs having such a configuration have a high bending elastic modulus and high bending strength, and can be manufactured at a lower cost than carving a carbon fiber sheet. , which is lighter than a metal one and can have substantially the same strength as a metal one.

Thermoplastic resin, which is the molding resin for tent pegs, includes highly heat-resistant engineering plastics such as polyethylene, polypropylene, polystyrene, ABS resin, polyamide resin, polyetheretherketone, polyetherimide, and polyethersulfone. can be used. In particular, polyamide-based resins are preferable from the viewpoint of the balance between processing cost and excellent mechanical properties and impact strength.

A well-known thing can be used as said polyamide-type resin.
Specifically, for example, polycapramide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-ω-aminononanoic acid (nylon 9), polyundecaneamide (nylon 11), polylauryllactam (nylon 12 ) and other homopolymers. Copolymerized polyamide resins include polyethylenediamineadipamide (nylon 26), polytetramethyleneadipamide (nylon 46), polyhexamethyleneadipamide (nylon 66), polyhexamethylenesebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyoctamethylene adipamide (nylon 86), polydecamethylene adipamide (nylon 108), caprolactam/lauryllactam copolymer (nylon 6/12), caprolactam /ω-aminononanoic acid copolymer (nylon 6/9), caprolactam/hexamethylenediammonium adipate copolymer (nylon 6/66), lauryllactam/hexamethylenediammonium adipate copolymer (nylon 12/66), Ethylenediamine adipamide/hexamethylenediammonium adipate copolymer (nylon 26/66), caprolactam/hexamethylenediammonium adipate/hexamethylenediammonium sebacate copolymer (nylon 66/610), ethyleneammonium adipate/hexamethylene Aliphatic polyamides such as diammonium adipate/hexamethylenediammonium sebacate copolymer (nylon 6/66/610), polyhexamethyleneisophthalamide, polyhexamethyleneterephthalamide, polymetaxylyleneadipamide, hexamethyleneisophthalate Amide/terephthalamide copolymers, aromatic polyamides such as poly-P-phenylene terephthalamide and poly-P-phenylene/3-4'diphenyl ether terephthalamide, amorphous polyamides, these polyamide resins with methylenebenzylamine , meta-xylylene diamine modified with an aromatic amine such as meta-xylylene diamine and meta-xylylene diammonium adipate.
Among polyamide-based resins, aromatic polyamides and linear polyamides are preferable, and those having aromatic rings are more preferable because of their high flexural modulus and flexural strength.

Carbon fiber, glass fiber, cellulose fiber, aramid fiber and the like can be used as the fibrous material contained in the thermoplastic resin. Carbon fiber is preferred because of its high strength and good adhesion to the resin.
As the carbon fiber, both PAN-based carbon fiber made from polyacrylic fiber and pitch-based carbon fiber made from pitch, which is a residue of petroleum refining, can be used.
The diameter of the carbon fibers is not particularly limited, but the average fiber diameter is usually 1-30 μm, preferably 3-20 μm, more preferably 5-15 μm.
As for the content, the higher the strength, the better. When the total amount of the thermoplastic resin is 100% by mass, the content is 10% by mass or more, further 20% by mass or more, and furthermore 25% by mass or more. preferably. In general, if the content exceeds 60% by mass, the fluidity of the fiber becomes low even if the resin is melted, and molding tends to be difficult. is preferably the content of

The tent peg of the present invention is molded by injecting and filling a molten thermoplastic resin containing the fibrous material into an injection mold, and cooling and solidifying the molten resin in the mold. In this case, the gate that fills the mold with molten resin should be placed at the top of the peg along the axial direction (direct gate), while it should be placed on the side perpendicular to the axial direction of the peg (side gate). ), the molded pegs tend to have slightly better flexural properties than if the However, with the direct gate, cracks may occur at the tip during the peg driving test, as described later. It is speculated that this is because jetting made the ends of the pegs fragile. In order to eliminate uneven distribution of strength and flexural elasticity and make the strength and flexural modulus uniform throughout the peg, it is considered preferable to adopt a side gate that allows the molten resin to diffuse at a uniform speed in the mold. .

The tent pegs of the present invention will be described in further detail based on the illustrated forms and embodiments. It should be noted that the embodiments and examples shown below are examples for embodying the technical idea of the present invention, and the present invention is not limited to those described below.

FIG. 1 shows an embodiment of the tent peg of the present invention, showing the appearance of the peg used for performance evaluation in the examples.
The peg for a tent of the present invention is molded by injecting and filling a molten resin obtained by impregnating a fibrous material in a thermoplastic resin into an injection molding die and cooling and solidifying it. A hook portion 11 for hooking a rope is provided at the tip portion thereof, and a rod portion 12 for sticking into the ground is projected from the lower end of the hook 11. - 特許庁

The length of the peg 1 is preferably 180 mm or more and 400 mm or less. If it is 180 mm or more, the operation of hitting the tip portion with a hammer while holding the peg with one hand can be performed easily, safely and reliably. If the length is 400 mm or less, the stick portion 12 that sticks into the ground does not become too long, and the driving operation of the peg 1 can be easily performed.
As for the thickness of the rod portion 12, the diameter is preferably 7 mm or more and 15 mm or less. If the diameter is 7 mm or more, the bending strength of the rod portion 12 can be obtained. If the diameter is 15 mm or less, it is possible to reduce the resistance when hammering the peg 1 .
As the cross-sectional shape of the rod portion 12, a circular shape, an elliptical shape, a square shape, a polygonal shape such as a hexagonal shape, an octagonal shape, and an appropriate shape can be adopted. If the shape is an oval shape or a polygonal shape of hexagon or more, the thermoplastic resin containing the fibrous material can be uniformly injection-molded, and the rotational displacement of the peg 1 in the axial direction after the peg 1 is fixed can be reduced. can be suppressed.

As for the shape of the tip of the peg 1, it is preferable that the tip gradually tapers from the rod portion 12 and the tapered tip has a radius of curvature of 2 mm or more and 10 mm or less. If the curvature radius of the tip is 2 mm or more, the tip can be prevented from being damaged when the peg 1 is hammered. If the radius of curvature of the tip is 10 mm or less, the peg 1 can be easily hammered into the peg 1 without excessive resistance to soil.

The shape of the hook portion 11 of the peg 1 is preferably formed in a bifurcated shape so that a rope or string can be hooked thereon, or a shape provided with a hole for tying a rope or string.
The width of the hook portion 11 is preferably set to be 1.1 times or more and 2.5 times or less the diameter of the rod portion 12 . If it is 1.1 times or more, the operation when driving the peg 1 with a hammer is easy and reliable, and if it is 2.5 times or less, the portion that protrudes to the side of the peg 1 does not get in the way and is easy to handle. No hindrance.
The length of the hook portion 11 is preferably 10 mm or more and 40 mm or less in the length direction of the peg 1 . If the length of the hook portion 11 is 10 mm or more, it is possible to prevent the rope or string from coming off when it is engaged. If the length is 40 mm or less, it is possible to suppress cracking at the hook portion 11 even if the hook portion 11 is driven into the soil by driving the peg 1 too much.
The peg 1 of the illustrated form has a thick and rounded tip portion of the hook portion 11 to make the shape difficult for the rope to come off, and when the peg 1 is driven, the hook portion 11 does not easily sink into the ground. , and is formed in a size that is difficult to break. The diameter of the hole through which the rope of the hook portion 11 is passed is set to be slightly larger than the thickness of the rod portion 12 of the peg 1 .

In the following examples, the shape shown in FIG. Peg 1 with a dimension of 9.315 mm was molded with different molding materials, and its performance was evaluated. The rod portion 12 actually has an octagonal cross section, and the tip end is tapered so that the entire length is not the same thickness. I assumed and evaluated.

FIG. 2 shows a schematic test system of the bending test performed in Examples.
In the bending test, a universal material testing machine: AG-50kNXplus (manufactured by Shimadzu Corporation) was used as a testing machine, and as shown in the figure, the peg 1 was placed under the part 50 mm away from the center in the axial direction. Each side is supported, and a three-point (fulcrum, load) bending is applied to the center of the peg 1 from above (white arrows in the figure), and the bending elastic modulus and bending strength of the peg are measured. Derived. The test speed was set at 5 mm/min.
The flexural modulus was calculated from the stress and strain values at load 35N and load 60N from the [obtained stroke (mm) - load (N)] curve. In addition, the diameter of the rod portion 12 of the peg 1 was calculated assuming that it had a circular cross-sectional shape with the above dimensions.
Also, the bending strength was calculated from the load when the peg broke. It is the same as above that the rod portion 12 of the peg 1 has a circular cross section.

FIG. 3 shows a schematic test system of the pull-out test performed in the examples. A pull-out test was performed as follows.
As shown in the figure, a portable tripod stand 2: KT-10 (manufactured by Takoman Co., Ltd.) has a pulley 3 supported at the bottom of the stand. Rope), connect the upper hook of the suspension scale dial type 5: T-100 to one end of this rope, and further to the lower hook of the suspension scale 5, to the hook part 11 of the peg 1 The ends of the fastened handy rope 4 were connected.
The tip of the rod portion 12 of the peg 1 is applied to the hard ground 6, and the tip of the peg 1 is hit with a 500 g hammer (black arrow in the figure) to pierce the rod portion 12 of the peg 1 into the ground 6. rice field. At this time, the crossing angle between the shaft portion (rod portion 12) of the peg 1 stuck in the ground 6 and the ground 6 is 60°, and the rope 4 connected to the lower hook of the suspension scale 5 is positioned with respect to the axial direction of the peg 1. The lower end of the hook 11 was pierced to a depth where it touched the ground.
Then, the other end of the rope 4 hung around the pulley 3 is applied with a load vertically downward (white arrow in FIG. The dial type value of hanging scale 5 was recorded.

(Example 1)
A mold for molding the peg shown in FIG. 1 was prepared and attached to an injection molding machine: Logoshot 100t (manufactured by Fanuc Corporation).
KayronMAX S4240 (manufactured by Mitsubishi Chemical Advanced Materials Co., Ltd., aromatic polyamide resin: PPA, carbon fiber content 40 wt%) is used as a thermoplastic resin containing fibrous materials that are molding materials, and the injection molding machine is used. Molten resin was injected and filled into the mold to form pegs.
The molding was performed under the following molding conditions: resin drying temperature of 80° C. for 3 hours or more, molding temperature of 330° C., mold temperature of 140° C., injection time of 0.97 seconds, and cooling time of 30 seconds. The mold has a gate (side gate) arranged on the side perpendicular to the axial direction of the peg.

The molded pegs were weighed and subjected to the flexural and pullout tests described above to determine flexural modulus, flexural strength and pullout force. These measurements were performed with 2 N numbers (two pegs) for mass, 3 N numbers (three pegs) for bending tests, and 2 N numbers for pullout tests, and the average value was taken as the measured value. .
Also, in the pull-out test, the state of the tip of the peg when the peg was driven into the ground by hitting with a hammer was visually confirmed.
The measurement results and confirmation results are shown below.
・Flexural modulus: 24777 N/mm ² (24.8 GPa)
・Bending strength: 495 N/mm ² (495 MPa)
- Withdrawal force: It did not break at 60 kgf and did not come off the ground.
・Mass: 31.5g
・No deformation of the tip of the peg was confirmed.

(Example 2)
With the same mold, injection molding machine and molding conditions as in Example 1, except that KayronMAX S2330 (manufactured by Mitsubishi Chemical Advanced Materials Co., Ltd., aromatic polyamide resin: PPA, carbon fiber content 30 wt%) was used as the molding material, molded pegs.
The same measurements and confirmations as in Example 1 were performed on the molded pegs. The results are shown below.
・Flexural modulus: 15551 N/mm ² (15.6 GPa)
・Bending strength: 420 N/mm ² (420 MPa)
・Pull-out force: Broken at 60 kgf (broken without the peg coming off the ground when the pulling force reached 60 kgf)
・Mass: 28.8g
・No deformation of the tip of the peg was confirmed.

(Example 3)
TLP-1060 (manufactured by Toray Industries, Inc., linear polyamide resin: PA (6 nylon), carbon fiber content: 30 wt%) is used as a molding material, and the gate of the mold is the tip of the peg (top). A peg was molded using the same mold, injection molding machine, and molding conditions as in Example 1, except that it was placed in (direct gate).
The same measurements and confirmations as in Example 1 were performed on the molded pegs. The results are shown below.
・Flexural modulus: 16090 N/mm ² (16.1 GPa)
・Bending strength: 389 N/mm ² (389 MPa)
・Pull-out force: Broken at 39 kgf (broken without the peg coming off the ground when the pulling force reached 39 kgf)
・Mass: 28.3g
・Cracks were found at the tip of the peg.

(Example 4)
A peg was molded using the same molding material, mold, injection molding machine and molding conditions as in Example 3, except that the gate of the mold was arranged as a side gate.
The same measurements and confirmations as in Example 1 were performed on the molded pegs. The results are shown below.
・Flexural modulus: 12547 N/mm ² (12.5 GPa)
・Bending strength: 366 N/mm ² (366 MPa)
・Pull-out force: broken at 10 kgf (broken without the peg completely coming off the ground when the pulling force reached 10 kgf)
・Mass: 28.3g
・No deformation of the tip of the peg was confirmed.

(Example 5)
Pyrofil NXMR-C40B (manufactured by Mitsubishi Chemical Co., Ltd., aromatic polyamide resin: PA (MXDA), carbon fiber content 40 wt%) is used as a molding material, and the direct gate arrangement is used with the molding die of Example 1. Using the same injection molding machine as in Example 1, pegs were molded.
The molding was performed under the following molding conditions: resin drying temperature of 90° C. for 3 hours or more, molding temperature of 270° C., mold temperature of 110° C., injection time of 0.97 seconds, and cooling time of 30 seconds.
The same measurements and confirmations as in Example 1 were performed on the molded pegs. The results are shown below.
・Flexural modulus: 24407 N/mm ² (24.4 GPa)
・Bending strength: 547 N/mm ² (547 MPa)
- Withdrawal force: It did not break at 60 kgf and did not come off the ground.
・Mass: 31.5g
・Cracks were found at the tip of the peg.

(Example 6)
A peg was molded using the same molding material, mold, injection molding machine and molding conditions as in Example 5, except that the gate of the mold was arranged as a side gate.
The same measurements and confirmations as in Example 1 were performed on the molded pegs. The results are shown below.
・Flexural modulus: 22784 N/mm ² (22.7 GPa)
・Bending strength: 531 N/mm ² (531 MPa)
- Withdrawal force: It did not break at 60 kgf and did not come off the ground.
・Mass: 31.5g
・No deformation of the tip of the peg was confirmed.

(Example 7)
SEREEBO DSP201 (manufactured by Teijin Limited, polycarbonate resin, carbon fiber content: 25 wt%) was used as a molding material, and pegs were molded using the same mold and injection molding machine as in Example 1.
The molding was performed under the following molding conditions: resin drying temperature: 120° C. for 3 hours or longer, molding temperature: 300° C., mold temperature: 110° C., injection time: 0.97 seconds, and cooling time: 30 seconds.
The same measurements and confirmations as in Example 1 were performed on the molded pegs. The results are shown below.
・Flexural modulus: 13441 N/mm ² (13.4 GPa)
・Bending strength: 234 N/mm ² (234 MPa)
・Pull-out force: broken at 10kgf (broken without the peg completely coming off the ground when the pulling force reached 10kgf)
・Mass: 29.4g
・Cracks were found at the tip of the peg.

(Reference example)
AW3G6 (manufactured by BASF Japan Ltd., linear polyamide resin: PA (66 nylon), glass fiber content 30 wt%) is used as the molding material, and the same mold and injection molding machine as in Example 1 are used to form pegs. bottom.
The molding was performed under the following molding conditions: resin drying temperature: 120° C. for 3 hours or more, molding temperature: 280° C., mold temperature: 130° C., injection time: 0.97 seconds, and cooling time: 30 seconds.
The same measurements and confirmations as in Example 1 were performed on the molded pegs. The results are shown below.
・Flexural modulus: 5382 N/mm ² (5.3 GPa)
・Bending strength: 248 N/mm ² (248 MPa)
・Pull-out force: broken at 10 kgf (broken without the peg completely coming off the ground when the pulling force reached 10 kgf)
・Mass: 30.5g
・No deformation of the tip of the peg was confirmed.

(Comparative example 1)
UMG1001 (manufactured by Techno Polymer Co., Ltd., ABS resin, containing no fibrous material) was used as a molding material, and the same mold and injection molding machine as in Example 1 were used to mold pegs.
The molding was performed under the following molding conditions: resin drying temperature: 80° C. for 3 hours or more, molding temperature: 220° C., mold temperature: 80° C., injection time: 1.8 seconds, cooling time: 30 seconds.
The same measurements and confirmations as in Example 1 were performed on the molded pegs. The results are shown below.
・Flexural modulus: 1820 N/mm ² (1.8 GPa)
・Bending strength: 76 N/mm ² (76 MPa)
・Pull-out force: The test could not be conducted because the pegs bent and did not stick to the ground even when hit with a hammer.
・Mass: 23.8g
・No deformation of the tip of the peg was confirmed.

Table 1 shows the molding materials and measurement results of each of the above Examples , Reference Example, and Comparative Example 1.

In addition, the same test as in the above example was conducted on commercially available tent pegs.
(Comparative example 2)
A PC hook peg of 23 cm (manufactured by Captain Stag Co., Ltd., ABS resin, containing no fibrous material, total length of 230 mm) was subjected to the same bending test, pull-out test, and mass measurement as in Example 1 above. The results are shown below.
・Flexural modulus: 2370 N/mm ² (2.4 GPa)
・Bending strength: 99 N/mm ² (99 MPa)
・Withdrawal force: Broken at 9 kgf ・Mass: 23.8 g

(Comparative Example 3)
A solid stake 30 (manufactured by Snow Peak Co., made of iron, total length 300 mm) was subjected to the same pull-out test and mass measurement as in Example 1 above. The results are shown below. Note that this peg is made of iron, and since it is clear that the peg exhibits a higher bending strength than the peg made of resin, no bending test was performed.
・Withdrawal force: No breakage at 60 kgf ・Mass: 179.1 g

(Comparative Example 4)
Uniframe Sea Peg 400 (manufactured by Shinetsu Works Co., Ltd., polyacetal resin, no fibrous material, total length 400 mm) was subjected to the same bending test, pull-out test, and mass measurement as in Example 1 above. The results are shown below.
・Flexural modulus: 1626 N/mm ² (1.6 GPa)
・Bending strength: 65 N/mm ² (65 MPa)
・Pull-out force: The test could not be conducted because the pegs bent and did not stick to the ground even when hit with a hammer.
・Mass: 87g

Table 2 shows the test results of Comparative Examples 2 to 4.

From the measurement results of each of the above Examples and Comparative Example 1, it is possible to mold pegs for tents with good bending strength and bending elastic modulus and high hardness by injection molding using a material containing a fibrous material in a thermoplastic resin. I was able to confirm something.
In addition, it was confirmed that the tent pegs of each of the above examples had significantly higher flexural strength and flexural modulus than the commercially available resin pegs of Comparative Examples 2 and 4. It was verified that a resin peg that is superior in rigidity and flexural elasticity to a peg made of resin can be produced. In addition, the weight of the tent pegs of each of the above examples is 1/5 or less of the iron peg of Comparative Example 3, and it is clear that the tent pegs of the present invention contribute to weight reduction of camping luggage.
Among the pegs for tents of each of the above examples, those of Example 1, Example 5, and Example 6, which were molded using an aromatic polyamide resin containing carbon fiber as the molding resin, exhibited excellent bending strength and It was confirmed that the flexural modulus was extremely good and the measurement result of the pull-out force was also good.
In addition, with the direct gate, jetting occurs and the tip tends to crack, but with the side gate, it was confirmed that a strong tip can be obtained.

Further, based on the test results of each of the above Examples and Comparative Examples 2 to 4, the practical performance required for tent pegs can be considered as follows.
In general, there is the following relational expression between wind speed (V) and wind pressure (P).
P=1/2ρV ² (ρ: air density)
Here, if the air density is 1.225 kg/ ^m3 when the temperature is 15°C and the atmospheric pressure is 1013.25 hPa, and the wind speed is 5-8 m/sec, the wind pressure is about 15.3-39. .2 Pa=1.6 to 4 kgf/m ² .
For example, if the wind speed is 15 m/sec or more, the wind pressure is about 138 Pa = 14.1 kgf/m ² or more, and if the wind speed is 19 m/sec or more, the wind pressure is about 221 Pa = 22.6 kgf/m ² and the wind speed is 20 m/sec or more. Then, the wind pressure is about 245 Pa=25 kgf/m ² .
Suppose that there is a tent of the shape and size shown in FIG. 4, and the poles are fixed by four ropes and pegs, one side of the tent receives the wind perpendicularly. Since the area of this side is 5 m ² , it will receive a load of about 8 to 20 kgf when the wind speed is 5 to 8 m/sec. At this time, since the two ropes and pegs support the pole of the tent, a load of 4 to 10 kgf is applied to each rope and peg. Similarly, when the wind speed is 15 m/sec, the load on each rope and peg is 35.3 kgf, when the wind speed is 19 m/sec, the load is 56.4 kgf, and when the wind speed is 20 m/sec, the load is 63.5 kgf.
From these facts and the test results of each of the above examples and comparative examples, a tent with a size for 4 to 6 people as shown in FIG. It is presumed that a peg of 5000 N/mm ² can be used in an environment with a wind speed of up to 8 m/sec. .
From the examples, in order to use it safely at a wind speed of 5 to 8 m/sec, it is sufficient that the pull-out force is about 10 kgf or more and the elastic modulus is 5000 N/mm ² or more, and the elastic modulus is 10000 N/mm ² or more and the pull-out force is 10 kgf. If there is more than this, it is speculated that it can be used more safely.
Similarly, if the pull-out force is 35 kgf and the modulus of elasticity is 15000 N/mm ² or ^more , it can be used up to a wind speed of about 15 m/sec. /sec or more and less than 20 m/sec.

From these facts, it is considered that, practically, if the tent peg has a flexural modulus of 5000 N/mm ² or more, the peg will not bend during use. Considering use in strong winds, it is preferably 10,000 N/mm ² or more, more preferably 15,000 N/mm ² or more, so that it can be used safely even in strong winds.
Practically, if the tent peg has a pull-out force of 9 kgf or more, it is considered that the peg will not come off during use. Considering use in strong winds, it is preferable that the pull-out force be 30 kgf or more.

(Example 9)
Using three pegs obtained in Example 5 (Peg 1, Peg 2, Peg 3), each peg was cut with a water jet machine along the AD-AD line shown in FIG. 1, that is, the axis of the peg. It was bisected lengthwise by cutting at a point along the axis through the center. Photographs were taken of the cut half surface on one side and the cut half surface on the other side of each cut peg, and the cut surface of the tip portion where the outer diameter becomes narrower. The captured image is shown in FIG.
When the cut surface of each peg was observed, as shown in the figure, it was observed that there were void walls due to air bubbles that were present in the molten resin during molding. The term "empty wall" as used herein refers to a gap formed by air without being filled with resin.
Based on the pulp-debris measurement method specified in JIS P 8208, the size of the observed cavity wall was measured using the debris measurement chart of the same measurement method. The measurement was performed in a range of 20 mm from the tapering boundary of the tip of the peg to the tip, that is, from the portion where the outer shape of the peg starts to shrink to the tip (the range indicated by L20 in FIG. 6).
FIG. 6 is a schematic diagram of FIG. 5, in which reference numeral V is attached to empty walls having a cross-sectional area of 0.3 mm ² or more as a result of the above measurement.
In FIG. 6, the size of the empty wall V11 of the peg 1 is 2.0 mm ² , the empty wall V12 is 0.5 mm ² , the empty wall V13 is 1.0 mm ² , and the empty wall V21 of the peg 2 is 1.0 mm 2 . 5 mm ² , the empty wall V22 was 1.0 mm ² , the empty wall V31 of the peg 3 was 0.3 mm ² , the empty wall V32 was 0.3 mm ² , and the empty wall V33 was 0.1 mm ² .

(Example 10)
Using three pegs obtained in Example 6 (Peg 4, Peg 5, and Peg 6), each peg was cut in the same manner as in Example 9, and the cross section was photographed. FIG. 7 shows the photographed image, and FIG. 8 shows a line drawing of the image.
Also, in the same manner as in Example 9, the size of the void wall exposed in the cross section was measured. As a result, the measured cavity wall had a cross-sectional area of 0.2 mm ² or less, and nothing larger than that.

According to the cross-sectional observation of Example 9, a hollow wall with a cross-sectional area of 0.3 to 2.0 mm ² was confirmed at the tip of the peg.
As shown in Table 1, the peg of Example 5 was molded by injecting resin into a mold by a direct gate method (injecting resin in the same direction as the longitudinal direction of flow). The reason why the void wall of the above size was confirmed at the tip of this peg is that jetting occurs and the injected resin cools down and cannot be sufficiently mixed with the resin to be filled later. It is thought that air bubbles were likely to form at the contact area between the resin that initially flowed in and the resin that came in later, and these air bubbles formed the void walls .
On the other hand, according to the cross-sectional observation of Example 10, only a void wall with a maximum cross-sectional area of 0.2 mm ² was confirmed in the range of 20 mm from the tip of the peg, and most of the large void walls were observed. Not confirmed.
As shown in Table 1, the peg of Example 6 was molded by injecting resin into a mold by a side gate method (injecting resin in a direction perpendicular to the longitudinal direction of flow). The reason why a large empty wall cannot be formed at the tip of the peg is that, in the case of the side gate method, jetting is less likely to occur, and the injected resin can be densely filled without entraining air bubbles to the tip of the peg. It is presumed that no large air bubbles were formed at the tip, resulting in the formation of large void walls .
As mentioned above, the direct gate causes jetting, so the tip may be easily cracked. However, it was confirmed by observing the cut surface of the peg that the side gate can provide a strong tip. .

1 tent peg (peg), 11 hook, 12 rod, 2 portable tripod stand, 3 pulley, 4 handy rope, 5 suspension scale, 6 ground, V empty wall

Claims (5)

A tent peg made of a thermoplastic resin containing carbon fiber and having a flexural modulus of 10000 N/mm ² or more. In a cross section cut at the axis in the axial direction of the peg,
2. The tent peg according to claim 1, wherein there is no empty wall with a cross-sectional area larger than 0.20 mm ² within 20 mm from the tip of the peg as measured by the pulp-debris measuring method specified in JIS P 8208. The tent peg according to claim 1 or 2, wherein the thermoplastic resin is a polyamide resin. 4. The tent peg according to claim 3, comprising a polyamide resin having an aromatic ring. 3. A tent peg according to claim 1 or 2, wherein the peg has a pull-out force of 9 kgf or more when a pull-out test is performed in the following test system.
(Test system) A peg is pierced into the hard ground so that its axial direction forms a crossing angle of 60° with respect to the ground surface. Wrap the end of the wire around the top of the peg, pull the other end of the wire in the direction perpendicular to the axial direction of the peg, measure the load applied to the peg, and when the peg comes off the ground, the peg breaks or The load at the time of breakage is defined as the pull-out force of the peg.

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