Fastening pin and manufacturing method thereof

The present invention relates to a fastening pin for a hard driven member used for fastening a thin steel plate such as a metal fitting or a plate to a hard driven member such as concrete or metal steel, and a method for forming the same.

Generally, in buildings such as buildings and civil engineering structures such as bridges and tunnels, compressed air, combustion gas, and explosives are used to fasten thin steel plates such as metal fittings and plates to hard driven members such as concrete and metal steel. It is used to drive and fasten with a tool that uses a drive source such as.

In conventional general buildings, as a construction method for the above-mentioned applications, fastening with concrete pins as shown in patent documents has come to be widely used from the viewpoint of work efficiency. Therefore, a concrete pin having a large diameter on the head side of the shaft portion and a small diameter on the tip side has been proposed and implemented.

<p num="0004"><patcit num="1"><text>Japanese Unexamined Patent Publication No. 2008-115995</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 11-257315</text></patcit><patcit num="3"><text>Japanese Unexamined Patent Publication No. 2008-51153</text></patcit></p>

<p num="0005"> However, since hard concrete is used for high-strength building properties, conventional concrete pins have a large step in the middle part and the taper angle on the head side is too large, so the driving resistance is large. , The lower part of the head was easy to bend, and it was easy for poor driving to occur. Further, in recent years, the strength has generally been increased, and in concrete buildings, the number of renovations has increased, and there is a need for pins that can be fastened to harder members, such as hardening due to the age of concrete. As a matter of course, the power of the above power source is also required for driving into a hard member of about 60 Newton or more, but the size of the driving tool itself reduces the penetration resistance to the member and the penetration into the member. After that, the fastening force to the member (pin holding force) is required.</p><p num="0006"> When driving a concrete pin into a hard member, the tip is made to penetrate by driving it almost perpendicular to the member, but because of the hard member, the bearing capacity under the neck just below the shaft and head is required, and this is not sufficient. The shaft is bent and the lower part of the neck is broken, which is an obstacle to fastening. When using stepped pins to handle extremely hard concrete such as ultra-high-strength concrete, which is currently being developed and put into practical use, the shaft diameter is large and the penetration resistance is also large in order to increase the strength, resulting in sufficient power. Need a certain tool.</p><p num="0007"> Further, it is not easy to manufacture a concrete pin in which the entire shaft portion is tapered or the neck portion is rounded, and the larger the shaft diameter of the pin, the higher the strength, but the higher the cost. Therefore, in order to obtain a fastening pin having a large shaft diameter and high strength, it is necessary to select a metal wire having a large outer diameter as a material, which causes a problem of high cost.</p><p num="0008"> The first object of the present invention is to solve the above-mentioned problems and to provide a fastening pin that is hard to bend at the time of driving and can be effectively driven into a hard driven member.</p><p num="0009"> The second aspect of the present invention is to provide a method for forming a fastening pin, which can make the shaft diameter of the fastening pin larger than the diameter of the wire without increasing the diameter of the metal wire rod as a material. Make it an issue.</p>

<p num="0010"> In order to solve the first problem, the invention according to claim 1 comprises a diameter-expanded head portion and a shaft portion, and the shaft portion includes a large-diameter shaft portion below the diameter-expanded head portion and a large-diameter shaft portion. It is composed of an intermediate shaft portion below and a small diameter shaft portion from the intermediate shaft portion to the tip portion, and the large diameter shaft portion is<u style="single">、</u>Below the enlarged head<u style="single">Continuous to</u>With Earl Department<u style="single">、</u>The are part<u style="single">Continue below</u>With taper<u style="single">With</u>, The diameter-expanded head side is formed to have a large diameter, and the intermediate shaft portion<u style="single">, Continuously below the taper</u>A straight part with the same diameter, and the small diameter shaft part<u style="single">Is a lower taper portion continuous below the intermediate shaft portion, a straight portion having the same diameter continuous below the lower taper portion and having a diameter smaller than that of the intermediate shaft portion, and a lower intermediate shaft portion. It has a bullet-shaped tip that is continuous below the shaft, and the taper is 2 to 5 °.</u>It is characterized by that.</p><p num="0011"> According to the second aspect of the present invention, in the first aspect, the large-diameter shaft portion has a length of 1/3 or more of the shaft length, and the tapered portion connecting the rounded portion and the intermediate shaft portion is hard. It is characterized in that the penetration resistance to the member to be driven is kept small, the pull-out resistance after the driving is maintained, and the large-diameter shaft portion is set so as not to bend at the time of driving.</p><p num="0012"></p><p num="0013"> Claim<u style="single">3</u>The invention according to claim<u style="single">1 or 2</u>In, the above-mentioned rounded part is at the time of driving<u style="single">neck</u>The feature is that the lower part is set large enough not to bend.</p><p num="0014"></p><p num="0015"> Claim to solve the second problem.<u style="single">4</u>The invention according to claim 1 is a molding method in which a tapered portion of a fastening pin according to claim 1 is formed by two dies and a header processing die provided on the upper part of these dies so as to be movable up and down. The mating surfaces of the two molds have an upper space portion having a tapered portion with an inner diameter larger than the outer diameter of the wire rod used as the material for the fastening pin, and an inner diameter portion substantially the same as the outer diameter of the wire rod, and the bottom portion is closed. After continuously forming the lower space portion and arranging the wire rod in the upper space portion and the lower space portion in a state where the upper portion of the wire rod protrudes upward from the mating surface of the mold, the molds are combined and described above. Fix the wire rod and further the header processing mold<u style="single">To</u>It is characterized in that the upper end of the twisted wire is crushed and bulged outward to fill the tapered portion of the upper space of the mold.</p>

<p num="0016"> According to the invention of claim 1, the large-diameter shaft portion is formed by a rounded portion below the enlarged-diameter head and a tapered portion formed between the rounded portion and the intermediate shaft portion. Since the side is formed to have a large diameter, the strength of the lower part of the neck and the large-diameter shaft just below the enlarged head is large, and the bending of the large-diameter shaft and the stress concentration on the breakage in the lower part of the neck are alleviated. , Improved resistance to breakage When a blow is applied to the diameter-expanded head when driving a hard driven member, the diameter-expanded head and the large-diameter shaft portion are difficult to bend.</p><p num="0017"> Further, since the intermediate shaft portion is a straight portion having the same diameter, the penetration resistance at the time of driving does not increase, and the pull-out resistance after driving can be largely maintained.<u style="single"> In addition, since the tapered portion formed between the rounded portion and the intermediate shaft portion is 2 to 5 °, the penetration resistance to the hard driven member can be kept small, and the power required for driving is minimized. It can be suppressed to a high level, and the pull-out resistance after driving is well maintained. Further, since the strength of the large-diameter shaft portion is increased, the stress concentration on the bending of the large-diameter shaft portion at the time of driving is relaxed, and the proof stress against bending is improved.</u><u style="single"> Further, the small diameter shaft portion is located below the lower intermediate shaft portion having a diameter smaller than that of the intermediate shaft portion and having the same diameter, the tapered portion provided between the lower intermediate shaft portion and the intermediate shaft portion, and the lower intermediate shaft portion. Since it is formed from the provided cannonball-shaped tip, the penetration resistance of the tip is small, and the lower intermediate shaft part of the same diameter keeps the penetration resistance small, improves the pull-out resistance, and further lower middle. Since the tapered portion provided between the shaft portion and the intermediate shaft portion gradually increases the diameter, the strength up to the intermediate shaft portion can be increased.</u></p><p num="0018"> According to the invention of claim 2, the large-diameter shaft portion has a length of 1/3 or more of the shaft length, and the tapered portion connecting the radius and the intermediate shaft portion has a penetration resistance to a hard driven member. The structure is set so that the large-diameter shaft does not bend when driven, so the strength of the taper is increased, the stress concentration on the bending of the large-diameter shaft is alleviated, and the yield strength against bending is reduced. If 1/3 or more of the shaft length on the enlarged head side is held without bending at the time of driving, the driving energy is concentrated on the tip of the fastening pin. Further, since the penetration resistance is also kept small, it is possible to reliably drive the hard member to be driven. Further, since the structure retains the pull-out strength after driving, the fastening can be maintained for a long time.</p><p num="0019"></p><p num="0020"> Claim<u style="single">3</u>According to the invention according to the above<u style="single">neck</u>Since the lower part is set large enough not to bend, the stress concentration on the bending of the enlarged diameter head at the time of driving is relaxed, the proof stress against bending is improved, and the hard driven member can be reliably driven.</p><p num="0021"></p><p num="0022"> Claim<u style="single">4</u>According to the invention according to the present invention, the mating surfaces of the two left and right molds have an upper space portion having a tapered portion having an inner diameter larger than the outer diameter of the wire rod used as the material of the fastening pin, and substantially the same as the outer diameter of the wire rod. After continuously forming a lower space portion having an inner diameter and a closed bottom portion, and arranging the wire rod in the upper space portion and the lower space portion with the upper portion protruding upward from the mating surface of the mold. , The above wire rod is fixed by matching the mold, and the upper end of the wire rod is crushed by the header processing mold to bulge outward to fill the tapered part of the upper space of the mold, so it is special. A tapered portion having a diameter larger than the diameter of the wire rod used as the material can be formed on the fastening pin inexpensively and quickly without any processing.</p>

<figref num="1">Front view of concrete pin according to the present invention</figref><figref num="2">Perspective view of the concrete pin driven into hard concrete</figref><figref num="3">Perspective view of other forms of the concrete pin</figref><figref num="4">(a) to (c) are front views of concrete pins with grooves formed on the surface.</figref><figref num="5">(a) and (b) are explanatory views showing a method of forming the enlarged diameter head and the large diameter shaft portion of the concrete pin.</figref>

In FIGS. 1 to 9, reference numeral A is a concrete pin. This concrete pin A is an example of a fastening pin according to the present invention, and is used when fastening a thin iron plate to hard concrete exceeding 60 N (Newton), for example. The shaft portion 2 consists of a large-diameter shaft portion 2a below the enlarged head portion 1, an intermediate shaft portion 2b below the large-diameter shaft portion 2a, and a small diameter from the intermediate shaft portion 2b to the bullet-shaped tip portion. It is composed of a shaft part 2c. The dimensions of the concrete pin A, the total length is 19 mm, the diameter d of the enlarged head 1 is 6.25 mm, the shaft length of the shaft part 2 (the length from below the neck of the total length) l is 17.5 mm, and the large diameter shaft part 2a. The length l1 of the intermediate shaft portion 2b is 6.5 mm, the length l2 of the intermediate shaft portion 2b is 3.0 mm, the length l3 of the small diameter shaft portion 2c is 8.5 mm, and the diameter d1 of the intermediate shaft portion 2b is set to 2.96 mm.

A rounded portion (curved surface portion) 4 is formed on the outer surface of the lower neck portion 3 below the enlarged diameter head 1. The rounded portion 4 is set large enough so that the lower neck portion 3 does not bend when driven. In the case of the concrete pin A having the above dimensions, the rounded portion 4 of the lower neck portion 3 should be set to about R1.5. Good.

Next, the large-diameter shaft portion 2a has a length of 1/3 or more of the shaft length, and the large-diameter shaft portion 2a has a tapered portion 5 formed between the rounded portion 4 and the intermediate shaft portion 2b. It is provided so that the lower three sides of the neck have a large diameter. The tapered portion 5 that connects the rounded portion 4 of the lower part of the neck 3 and the intermediate shaft portion 2b is kept small so that the penetration resistance to the hard driven member does not increase, and the pull-out resistance after driving is maintained. The large-diameter shaft portion 2a is set so as not to bend during driving. The angle θ1 of such a tapered portion 5 is preferably set to 2 to 5 °.

The intermediate shaft portion 2b is a straight portion having the same diameter.

Next, the small-diameter shaft portion 2c includes a lower intermediate shaft portion 6 having a diameter smaller than that of the intermediate shaft portion 2b, a lower tapered portion 7 provided between the lower intermediate shaft portion 6 and the intermediate shaft portion 2b, and a lower intermediate shaft portion. It is formed from a tip portion 8 provided below 6. The angle θ2 of the lower tapered portion 5 is set to 10 °. The tip 8 has a length of 5 mm and is formed in a cannonball shape.

In the above configuration, since the rounded portion 4 of the lower neck portion 3 of the concrete pin A is formed to be considerably large at about R1.5, the strength of the lower neck portion 3 and the large-diameter shaft portion 2a is large, and the lower neck portion 3 is resistant to breakage. Since the stress concentration is relaxed, the proof stress against breakage is improved, and the diameter-expanded head 1 is less likely to bend when the diameter-expanded head 1 is hit when it is driven into a hard member to be driven.

Further, the large-diameter shaft portion 2a has a length of 1/3 or more of the shaft length, and the large-diameter shaft portion 2a has a length of 2 to 5 ° formed between the lower neck portion 3 and the intermediate shaft portion 2b. Since the tapered portion 5 is provided so that the lower neck portion 3 side has a large diameter, the strength of the lower neck portion 3 and the large diameter shaft portion 2a is increased, the stress concentration on the bending of the large diameter shaft portion 2a is relaxed, and the bending is performed. The large-diameter shaft portion 2a is less likely to bend when the diameter-expanded head 1 is hit when it is driven into hard concrete.

If the angle θ1 of the tapered portion 5 of the concrete pin A is smaller than 2 °, the diameter of the upper portion does not become sufficiently large, so that a predetermined strength (proof stress against breakage) cannot be secured, and the above angle θ1 If is larger than 5 °, the penetration resistance at the time of driving increases and the pull-out resistance (holding force) after driving cannot be obtained. Also, for manufacturing reasons described later, 5 ° is the limit. is there.

Since the intermediate shaft portion 2b is a straight portion having the same diameter, the penetration resistance to the hard driven member at the time of driving does not increase, and the pull-out resistance after driving can be largely maintained.

Further, the small diameter shaft portion 2c includes a lower intermediate shaft portion 6 having a diameter smaller than that of the intermediate shaft portion 2b and having the same diameter, and a lower tapered portion 7 provided between the lower intermediate shaft portion 6 and the intermediate shaft portion 2b. It is formed from a tip portion 8 provided below the lower intermediate shaft portion 6. The tip portion 8 has a bullet shape and its penetration resistance is small, and the lower intermediate shaft portion 6 having the same diameter keeps the penetration resistance small and improves the pull-out resistance, and further lower intermediate shaft portion 6 and the intermediate shaft portion 2b. Since the lower tapered portion 7 provided between the and the lower tapered portion 7 gradually increases the diameter, the strength up to the intermediate shaft portion 2b can be increased. The reason why the lower intermediate shaft portion 6 is formed to have the same diameter is to secure the pull-out resistance after driving, and the reason why the lower tapered portion 7 is set to 10 ° is that the small diameter shaft portion 2c. This is because the diameter on the tip side is reduced to some extent to reduce the penetration resistance to concrete.

As described above, the lower neck portion 3 is formed with a rounded portion 4, and the large diameter shaft portion 2a is large on the lower neck portion 3 side due to the tapered portion 5 formed between the rounded portion 4 and the intermediate shaft portion 2b. Since it is provided so as to have a diameter, the strength of the lower neck portion 3 and the large-diameter shaft portion 2a is large, and the bending of the large-diameter shaft portion 2a and the stress concentration on the break in the lower neck portion 3 are alleviated, and the bearing capacity against breakage is reduced. The diameter-expanded head 1 and the large-diameter shaft portion 2a are difficult to bend when the diameter-expanded head 1 is hit when the hard member to be driven is driven.

Further, since the intermediate shaft portion 2b is a straight portion having the same diameter, the penetration resistance at the time of driving does not increase, and the pull-out resistance after driving can be largely maintained.

From the above, as shown in FIG. 2, the concrete pin A can be reliably fixed to the hard concrete B with the thin iron plate material C. Since the thin plate material C is relatively soft, the rounded portion 4 under the neck can also be penetrated, and the concrete pin A is a connecting pin in which a plurality of pins are connected via a synthetic resin connecting material (not shown). Since the concrete pin A is driven together with the connecting material separated from other concrete pins at the time of driving, the rounded portion 4 penetrates into the thin plate material and the connecting material D, and the penetration resistance of the rounded portion 4 is large. Since concrete hardly penetrates, there is no problem of driving failure.

The concrete pin A is not limited to the above-mentioned form. For example, as shown in FIG. 3, the large-diameter shaft portion 2a may be formed in two stages, the tapered portion 5 may be formed in the lower portion, and the upper portion may be formed as a straight portion 9 having the same diameter. In this case, the tapered portion 5 can secure the proof stress against bending of the large-diameter shaft portion 2a, and the straight portion 9 can maintain a high holding force after driving.

Further, the intermediate shaft portion 2b may be lengthened and directly connected to the bullet-shaped small diameter shaft portion 2c.

Further, in each of the above embodiments, as shown in FIGS. 4A to 4C, knurled grooves 10 and diagonal parallel grooves 11 are machined and formed on the surface of the shaft in order to increase the holding force after driving. You may. The same applies to the concrete pins and the like shown in FIG.

The large-diameter shaft portion 2a above the concrete pin A is larger than the outer diameter of the metal wire (carbon steel wire) which is the material of the concrete pin A by the amount of the tapered portion 5. As shown in FIG. 5A, such a tapered portion shape is machined and molded by two left and right dies 12 and an upper header processing die 13.

That is, a space portion 16 including an upper space portion 14 and a lower space portion 15 is formed on the mating surface of both the left and right molds 12. The tapered portion 5a and the rounded portion 4a are formed so that the inner diameter of the upper space portion 14 is larger than the outer diameter of the wire rod 15 and larger than the lower portion, and a circular recess 17 is formed at the upper end. The inner diameter of the lower space portion 15 is formed to be substantially the same as the outer diameter of the wire rod 15. The upper end of the upper space portion 14 is open, but the lower end of the lower space portion 15 is closed. In this case, the lower mold 18 may be fixed below the mating surface of the two molds as shown in the figure, but the lower mold 18 is formed on one or both of the left and right molds 12 and the molds are formed. The space portion 16 may be closed when the 12s are combined. The header processing die 13 is arranged so as to be vertically movable above the mating surface of the two molds 12. A recess 20 corresponding to the enlarged diameter head 1 of the concrete pin A is formed on the lower surface of the header processing die 13. As a result, a space for the head that conforms to the outer shape of the enlarged head 1 is formed between the circular recess 17 at the upper end of the mating surface of the mold 12 and the lower surface of the header processing mold 13.

When forming the tapered portion 5 on the upper part of the concrete pin A by the above mold, first, the iron wire rod 21 (carbon steel wire) having the same diameter as the diameter of the intermediate shaft portion 2b is inserted into the space portion 16 of the two molds 12. Place it inside. At this time, the upper end of the wire rod 21 is projected above the mold 12. Then, the two molds 12 are tightened to fix the wire rod 21. Next, as shown in FIG. 5 (b), the header processing die 13 is lowered and pressed down to the protruding portion to be crushed. As a result, the diameter-expanded head 1 is formed between the lower surface of the header processing die 13 and the circular recess 17 at the upper end of the die 12. At the same time, when the upper part of the wire rod 21 is crushed, the wire rod 21 is fixed in the space portion 16, and the upper space portion 14 is larger than the outer diameter of the wire rod 21. Since the rounded portion 4a and the tapered portion 5a are filled with the bulging so as to match, the rounded portion 4 and the tapered portion 5 are formed.

According to the above-mentioned taper portion forming method, a tapered portion 5 having a diameter larger than the diameter of the wire rod 21 as a material thereof can be formed on the fastening pin inexpensively and quickly without performing any special processing.

When forming a knurled groove or a parallel groove on the surface of the concrete pin A, the unevenness corresponding to each groove may be formed in the space of the mold.

As described above, by striking and crushing the protruding portion of the wire rod 21 with the header processing die 13, the upper portion of the wire rod 21 is inflated along the mating surface of the upper intermediate shaft portion 2b to form the tapered portion 5. However, such swelling molding is limited to the 5 ° tapered portion 5.

After the wire rod 21 is processed as described above, the shape of the small diameter shaft portion 2c below the wire rod 21 may be further formed by a conventional method.

As described above, the large-diameter shaft portion 2a of the concrete pin A has a larger diameter than the metal wire rod 21 which is a material by the amount of the taper portion 5, but this tapered portion 5 is made of a metal wire rod by the header processing die 13. Since the upper part of 21 is crushed in the axial direction and bulged outward, it is not necessary to use a metal wire 21 having the same diameter as the upper end of the tapered portion 5, so that the manufacturing process can be completed. It is simplified and the cost can be kept low.

Although the above embodiment relates to a concrete pin, the present invention is not limited to concrete, and can be applied to a fastening pin to be driven into another hard driven member.

A concrete pin 1 Expanded head 2 Shaft 2a Large diameter shaft 2b Intermediate shaft 2c Small diameter shaft 4 Earl part 5 Tapered part 12 Mold (left and right) 13 Header processing die 14 Upper space 15 Lower space 16 Space 21 Wire rod