JPS61201910A - Screw nail and split mold for molding screw nail - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to screw nails and die-casting proportions used to manufacture the screw nails.

Conventional technology] For example, gypsum board, ALC board, etc., which do not have post-painting,
Tarapig screw nails are used when fixing various parts to fragile materials (hereinafter referred to as gypsum).

Screw nails that are screwed into gypsum board have a structure where the height of the screw is low and the pitch is short, which can destroy the gypsum board and make it impossible to withstand pulling force. Therefore, screw nails with the optimal structure for gypsum board are required. Become.

The applicant of this application is Jitsuganaki! 9-/θ was proposed by Kou No. 23, a tang screw nail with excellent pull-out resistance for plasterboard.

As shown in FIG. 7, the above-mentioned tapping screw nail has a screw 3 on the outer periphery of a shaft 2 having a head 1 at one end,
It has a structure in which a drill part S is connected to the other end of the shaft 2, the pitch of the screw 3 is larger than the diameter of the shaft 2, and the outer diameter of the screw is set to be more than twice the diameter of the shaft 2.

By the way, if the diameter d of the shaft 2 is 3Wφ, the screw pitch P = 11t■, the screw diameter D-1,j■φ
is formed.

Further, the drill part 5 has a conical tip at the tip of the circular shaft, and has a recess 5a in the axial direction of the outer peripheral surface so that the cross section has a substantially U-shape, and the recess has an opening along the axial direction. The edge is a cutting edge, and by pressing and rotating, the cutting edge cuts the gypsum board to make a pilot hole, and the recess 5a becomes a storage space for cutting waste.

The above-mentioned tapping screw uses the drill part 5 at the tip to drill a pilot hole in the plasterboard, and then inserts the screw 3 into the pilot hole.
In order to obtain strong pull-out strength without loosening against materials with no restoring elasticity such as gypsum board, the entire surface of the screw must be in close contact with the gypsum board. In order to satisfy this condition, the cross-sectional shape of the screw 3 must be made equal over the entire length.

By the way, as general methods for manufacturing screw nails, there are known methods that involve cutting or rolling, and a die-casting method that uses a mold.

First, the cutting method has the advantage of being able to finish the entire length of the screw into a uniform cross-sectional shape, but it is time-consuming, inefficient, and wasteful of materials, making the product extremely expensive. Shi, it's not practical.

Next, the rolling method requires manufacturing a die with a complicated shape, and as mentioned above, screw nails whose screw diameter is more than twice the shaft diameter cannot be manufactured by rolling.

Finally, manufacturing by die casting has the advantage of being able to provide inexpensive products because there is no wastage of materials and mass production is possible, while molding using molds makes it possible to remove the mold. As will be described in detail below, the shape of the screw is limited and it is not possible to form a screw with a cross-sectional shape that has a uniform overall length.

[Problem that the invention seeks to solve]

That is, when the molding concave part of the mold is made into a completely two-part shape of the screw, at both ends of the screw molding part in the Raku mold, the molding surface of the lower surface at the upper side end of the screw and the upper surface at the lower side end of the screw. However, the screw engages with the screw in the demolding direction of the mold, making demolding work impossible.

For this reason, in conventional molds, the portion of the screw forming surface where retention occurs during demolding is removed horizontally to avoid any hindrance to demolding.

When a screw nail is die-cast using such a mold, as shown in FIG.
When this screw nail is screwed into a gypsum board, the thick part where the screw enters will scrape off the gypsum board, creating a gap between the screw and the gypsum board, causing looseness and reducing the pull-out strength. There is a problem that the amount decreases.

This invention was made in order to solve the above-mentioned problems.This invention is a die-cast screw nail for gypsum board that has a uniform screw thickness over the entire length and has excellent pull-out resistance. The purpose is to provide a mold that can be used for die casting.

[Means for solving problems]

In order to solve the above-mentioned problems, the first invention has a structure that extends from the apex located in the center between the screws toward the screws at sliding positions on the outer peripheral surface of the shaft between the shaft centers. A triangular inclined plane part and a triangular plane part inclined upward from the bottom of the inclined plane part toward the base of the screw are formed in a symmetrical arrangement between the screws.

The second invention shows a groove on the abutting surface side of the two-split mold, and a molding recess 22, 22 of the screw nail is divided into two on the abutting surface side of both molds 21 and 21. The matching surfaces of the two molds 21, 21 are formed by forming a stepped portion 23 along the outer circumferential radial direction of one screw 13 and an adjacent stepped portion 23 which is inclined with respect to the axial direction of the shaft 12. Three inclined parts 24 connecting the ends and the outer ends are provided alternately to form seven uneven surfaces. 7. Note that the uneven surface described above is the trouble area of the screw forming part, and the abutting sharp part between the head 11 and the drill part 14 does not interfere with demolding, so it is formed by dividing it into two straight surfaces along the axis. , the head part 11 is formed by a head mold 26 in which the driver diagonal body mating groove 25 is removed from the mold in the axial direction.
As above, both molds 21
If the abutting surfaces of and 21 are anti-concave surfaces, the stepped portion 2
3 from the center to the end and the part from the tip to the center of the inclined part 24 protrude toward the mating mold side more than the maximum diameter part at the center of the screw nail, and these parts are attached to the shaft 12. 2, a triangular protrusion 27 is provided on the shaft molding surface of the molding recess 22 on the protruding side of the inclined part 24, as shown in FIG. During molding, shaft 12 and mold 2.2
This is to prevent interference with 1.

As shown in FIG. 1, the protrusion 27 prevents interference with the angle surface 27a of the skewer 13 forming the inclined plane part 15 and the direction of the triangular surface 2 forming the plane part 16.

In this way, the projection 27 forms a flat surface portion 1S on the outer peripheral surface of the shaft 12.
By forming the plane part 16 as a surface extending in the demolding direction, the abutting part in the molding part of the screw 13 can be demolded without any trouble, as shown in Fig.
As shown in Fig. 6, the screw can be molded to have a uniform thickness over its entire length, and a screw nail with excellent pull-out resistance can be manufactured by die-casting.

Effects] As described above, according to the present invention, since it has the above configuration, there are the following effects.

(I) At opposite positions on the outer circumferential surface of the shaft, sandwiching the shaft center, there is a triangular inclined plane part that spreads out toward the screw from the apex located in the center between the screws, and a screw Triangular flat parts that are sloped once toward the base of the screws are formed in a symmetrical arrangement between the screws, so when the screw nails are die-cast using a split mold, the flat parts provided on the shaft part It is possible to eliminate the occurrence of a retaining portion between the mold and the screw nail during demolding, and it is possible to manufacture a screw nail in which the screw has a cross-sectional shape with a uniform thickness over the entire length using a two-piece mold.

(Since the entire length of the ID screw has a cross section with a uniform thickness, there is no gap at the screw entry part when screwing into a non-shrinkable material such as gypsum board, and the pull-out strength is significantly increased. improve.

(2) The abutment surface of the two-split mold is divided into a stepped portion along the outer diameter direction of the screw and an inclined portion that is inclined with respect to the axial direction of the shaft and connects the inner and outer ends of the adjacent stepped portions. to form an uneven surface,
Since a triangular protrusion is provided on the protruding side of the inclined part on the shaft molding surface of the molding recess, the protrusion can prevent the generation of a retaining part between the screw nail and the mold in the demolding direction, and the two split metal Using a mold, it is possible to die-cast a screw nail with the same thickness as the entire length of the screw.

(To) It became possible to manufacture nails with the same thickness over the entire length of the screw using a mold, and it became possible to mass-produce nails with excellent pull-out resistance at a low cost.

[Brief explanation of drawings]

Figure 1 is a front view showing the abutting state of the two split molds, Figure 2 is a longitudinal sectional view showing the separated state of the same as above, Figure 3 is a sectional view along the arrow ■-■ in Figure 1, The figure is a cross-sectional view taken along the arrows ■-■ in Figure 7, Figure 5 is a perspective view showing the main parts of the mold, Figure 6 is a front view of the screw nail, and Figure 7 is a cross-sectional view of the main part of the mold. It is a front view showing a screw nail. DESCRIPTION OF SYMBOLS 11... Head, 12... Shaft, 13... Screw, 14... Drill part, 15... Inclined plane part, 16...
... Plane part, 21 ... Mold, 22 ... Molding recess, 2
3...Step part, 24...Slope part, 27...Protrusion, 2
7a, 27b... Triangular surface patent applicant Wakai Sangyo Co., Ltd. Agent Kama 1) Text 2 Figure 4 Figure 6 Figure 25 Figure 7

Claims (2)

[Claims] (1) For nails with screws on the outer circumferential surface of the shaft, triangular shapes that spread out from the apex located in the center between the screws toward the screw are placed at opposing positions on the outer circumferential surface of the shaft, sandwiching the axis center. A screw nail characterized in that an inclined plane part and a triangular plane part which slopes upward from the bottom of the inclined plane part toward the base of the screw are arranged symmetrically between the screws. (2) The molding concave part of the screw nail is divided into two on the abutting surface side of the two-split mold, and the abutting surface of both molds is connected to the stepped part along the outer circumferential direction of the screw and the axis of the shaft. tilted to the direction,
An uneven surface is formed with an inclined part connecting the inner and outer ends of adjacent step parts, and a triangular protrusion is provided at a position on the protruding side of the inclined part on the shaft molding surface of the molding recess in both molds. Split mold for forming screw nails.