JPH02141B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing screw nails.

A screw nail with a multi-screw with a large lead angle formed on the outer circumferential surface of the shaft penetrates into the nailed object while forming a driving hole that matches the cross-sectional shape of the shaft, so it can be driven smoothly. It is widely used because it can be driven in and also exhibits high pull-out strength against linear pull-out force.

Conventionally, screw nails have been manufactured by twisting a metal plate with a rectangular cross section, resulting in problems such as poor processing efficiency and high processing costs.

By the way, since the above-mentioned screw nail simply has screws formed continuously, the shape of the driving hole and the outer surface of the shaft portion match, and the screw is easily guided in the direction of loosening by the driving hole. There is a problem that loosening is likely to occur when vibration or the like occurs.

In order to solve this problem with screw nails, a nail with a plurality of locking grooves provided in the crest of the screw was proposed in Japanese Utility Model Publication No. 56-28329.

The above-mentioned screw nail has a horizontal catch groove provided at the top of the screw, which causes the shaft part to catch on the object to be nailed. It is possible to securely fix even a small object.

The purpose of the present invention is to provide a method for manufacturing screw nails with a locking groove as described above that can be mass-produced at low cost. Using a wire rod, this wire is pressurized from the long diameter direction using a press mold divided in the short diameter direction to plastically deform it, forming a nail with a multi-thread screw on the outer circumferential surface of the shaft with a circular cross section. This is what I did.

As shown in FIG. 4a, when the press die 12 advances in the direction of the arrow, the long diameter side a of the wire rod 11 first touches the press die 1.
2, and by this pressurization, the wire rod 1
1 undergoes bulging deformation as shown by the arrow, then the bulging deformation portion is pressed against the press die 12, and finally the short diameter side b is press-molded. That is, plastic deformation is performed from the long diameter side a to the short diameter side b to obtain a nail (see Examples) having a multi-thread screw on the outer circumferential surface of the shaft portion having a circular cross section.

As shown in FIG. 4b, when the wire rod 11 is circular, as the press mold 12 pressurizes, the short diameter side b of the wire rod 11 first contacts and bulges in the direction of the arrow. Later, since the longer diameter side a is machined, the bulging and deformed portion protrudes onto the mating surface of the mold 12, making it impossible to perform sufficient pressing, and the shaft portion (the portion inside the chain line in FIG. 2) becomes elliptical. In this way, when burrs protrude or the shaft is oval, the screw nail cannot rotate while forming a driving hole that matches the cross-sectional shape of the shaft in the object being driven. Because it advances while moving, it cannot rotate and cannot perform the function of a screw nail.

Hereinafter, the present invention will be explained based on embodiments shown in the accompanying drawings.

FIG. 3 shows the completed screw nail 1, in which the head 4 is attached to the upper end of the shaft portion 3 whose lower end is the pointed end 2.
A plurality of screws 5 having a large lead angle are formed on the outer circumferential surface of the shaft portion 3, and a large number of screws are arranged horizontally at the peaks between the screws and at constant intervals in the axial direction. It is configured by providing a locking groove 6.

The above-mentioned latching groove 6 has an inclined circumferential surface 6a that gradually expands outward toward the upper end, and a latching groove that extends from the upper edge of this circumferential surface toward the axis of the shaft portion 3 and is approximately perpendicular to the axis. The inner end of the locking step 6 is located at the lower end of the upper inclined peripheral surface 6a.

Each of the locking grooves 6, which gradually deepen toward the tip of the shaft portion 3, is formed such that the diameter of the small diameter portion at the lower end of the inclined circumferential surface 6a is approximately equal to the diameter of the bottom of the screw 5. Each peak has a shape that is interrupted at each valley in the circumferential direction.

1 and 2 show the manufacturing process of the screw nail described above.

The shaft material 11, which is the raw material for the screw nail, is formed into an elliptical cross-sectional shape with a minor diameter and a major diameter, as shown in FIG. Press molds 12, 12 are used which are divided in the minor axis direction of the material 11.

The press molds 12, 12 have a molding surface 13 on which the shaft member 11 presses in the radial direction to cause plastic deformation, and is formed into a concave shape that matches the outer shape of the screw nail 1 shown in FIG. 2 when assembled.

In order to pressurize the shaft material 11, the first
As shown in the figure, the shaft material 11 is pressurized from the long-diameter side using press dies 12 and 12 . The shaft material 11 is
The amount of deformation in the major diameter direction increases, and the protruding portions of the molding surfaces 13 of the molds 12, 12 bite into the shaft material 11, and relief occurs in the short diameter direction and the recessed portions of the molding surfaces by the amount of biting. As shown in FIG. 2, when the shaft member 11 is completely pressurized by both the molds 12, 12, a screw 5 can be formed over the entire circumferential surface and a retaining groove 6 can be formed in the crest thereof.

Note that the head 4 and the sharp end 2 are formed using molds 12 and 1.
Although it may be done separately from the pressurizing step in step 2, efficiency will be improved if it is done in parallel.

When both molds 12 and 12 are separated after pressure molding,
A screw nail 1 as shown in FIG. 3 is completed.

Although the above embodiment shows the case where the locking groove 6 is molded at the same time, only the screw 5 may be pressure molded.

Since the present invention is constructed as described above, it is possible to reliably and efficiently manufacture a screw nail having a shaft portion having a circular cross section and a multi-thread screw on its outer circumferential surface, thereby reducing costs through mass production of screw nails. becomes possible.

[Brief explanation of drawings]

1 and 2 are cross-sectional views showing the processing order of the screw nail, FIG. 3 is a front view of the completed screw nail, and FIGS. 4 a and b are explanatory diagrams of the operation of this invention and other examples. It is. 1 is the screw nail, 2 is the sharp end, 3 is the shaft, 4
1 is a head, 5 is a screw, 6 is a retaining groove, 11 is a shaft member, 12 is a mold, and 13 is a molding surface.

Claims (1)

[Claims] 1 A wire rod with an elliptical cross section, which has a short diameter and a long diameter, is plastically deformed by pressurizing it from the long diameter direction to the radial direction using a press mold that is divided in the short diameter direction. A method for producing a screw nail, comprising forming a nail with a row screw.