JP3167911U - Screw nails - Google Patents

Abstract

Provided is a screw nail that can be easily screwed into a hard synthetic plate material such as a particle board or a decora board without falling down. A tip cutting edge 2a2 is provided on a screw nail. The tip cutting edge 2a2 is provided at a shallow angle with respect to a plane passing through the tip 2a1 on the center line C of the screw shaft portion 2c of the screw nail and orthogonal to the center line C. The thread 3 starts from the tip portion with the tip cutting edge 2a2. Thereby, the cutting speed of the tip cutting edge 2a2 is remarkably increased as compared with the conventional screw nail. [Selection] Figure 2

Description

  The present invention relates to a screw nail suitable for being screwed into a hard synthetic plate material such as a particle board or a decora board.

Conventionally, screw nails are used instead of nails. For example, there exists an example shown by patent document 1 Unexamined-Japanese-Patent No. 2007-327540. Screw nails are easier to use than wood screws by screwing them into wood without providing pilot holes. Long screw nails can also be screwed in without providing pilot holes in the wood. It is no exaggeration to say that this screw nail has come to be used because of the widespread use of cordless drivers. When screwing a screw nail with a cordless screwdriver, hold it with the finger of one hand, touch the screw nail at the screwing position and hold the screw nail at a right angle to the plate surface, hold the cordless screwdriver with the other hand, The screwdriver fixed on the chuck is aligned with the cross groove on the head of the screw nail. Then, the screw nail is screwed into the plate material by driving the push rod cordless driver toward the screw nail.

A conventional screw nail can be easily screwed into solid wood. When trying to screw a conventional screw nail into a hard synthetic plate material such as particle board, decora board, etc. using a cordless screwdriver, the screw nail only rotates and is difficult to screw into the hard synthetic plate material and is sent to the cordless screwdriver. If you give it, the screw nail will fall down.

As shown in Japanese Patent Application Laid-Open No. 2006-308079, even if a screw nail having a groove in the axial direction is formed slightly obliquely from the tip of the screw nail, the screw nail often falls in the same manner.

Patent Document 1: Japanese Patent Application Laid-Open No. 2007-327540
Patent Document 2 JP 2006-308079 A

None

An object of the present invention is to provide a screw nail that can be easily screwed into a hard synthetic plate material such as a particle board or a decora board without falling down.

The inventor carefully observed the phenomenon that the screw nail fell when it was screwed into the plate with a cordless screwdriver. First, when a screw nail is stood on a soft material using a cordless screwdriver, the screw nail does not fall down and cannot be screwed in. When trying to screw a screw nail into the particle board with a cordless screwdriver, the feed force applied to the screw nail becomes large. This feed force is given by a hand with a cordless screwdriver.

On the other hand, the screw nail standing at the tip of the particle board is supported by the cordless screwdriver with the fingertip only at the moment when the screw nail starts to rotate. The screw nail only rotates around the tip of the screw nail on the particle board. The operator pushes the cordless screwdriver more strongly, but cannot keep the rotating threaded nail with his finger for a long time. Then the screw nail falls down.

Therefore, in this invention, in a screw nail having a thread 3 provided around a cylindrical shaft portion, the tip end portion of the shaft portion is tapered, and a cutting blade is provided at the tip end of the shaft portion in a radial direction from the center portion. The blade is a cutting edge provided at a shallow angle in the range of 0 to 45 degrees with respect to a plane perpendicular to the shaft portion, and a retreating cutting blade from the end on the outer peripheral side of the shaft portion of the tip cutting blade toward the head The screw nail is characterized in that the shaft portion is formed by providing an axial direction or a groove inclined with respect to the axial direction, and the screw thread is provided from the tip end portion of the shaft portion toward the head side of the screw nail. .

  The tip blade provided at a shallow angle in the range of 0 to 45 degrees with respect to the plane perpendicular to the shaft portion cuts the surface of the plate material at the beginning of rotation by the rotation of the screw nail. Since the screw thread enters the plate material with the subsequent retreating blade, the screw nail starts to be screwed into the plate material immediately, and then the screw thread is screwed in so that the screw nail does not fall down.

It is a side view of the Example of this invention. It is an enlarged view of the front-end | tip part of FIG. FIG. 3 is a left side view of FIG. 2. FIG. 3 is a plan view of FIG. 2. It is AA expanded sectional drawing of FIG. It is sectional drawing orthogonal to the front-end cutting edge of a front-end cutting edge part.

Embodiments of the present invention will be described below with reference to the drawings.

First, as a whole, the screw nail 1 is provided with a screw thread 3 around a cylindrical shaft portion 2. The shaft tip portion 2a is tapered, and a cutting blade 2a4 is provided at the shaft tip from the center in the radial direction. The cutting blade 2a4 is shallow in a range of 0 to 45 degrees with respect to a plane perpendicular to the shaft portion 2. An angled tip cutting edge 2a2 and a groove in which the receding cutting edge 2a3 is inclined to the shaft portion 2 in the axial direction or the axial direction from the outer peripheral end of the shaft portion of the tip cutting blade 2a2 toward the head 4 The screw nail 1 is formed by providing the screw thread 3 from the tip of the shaft portion toward the head 4 side of the screw nail.

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FIG. 1 is a side view of a screw nail. The tip 2a is tapered, and the space between the base 2b of the tip 2a and the neck portion 2b at the boundary with the head 4 of the screw nail has a cylindrical shape. It is smaller than the diameter of the head-side shaft portion 2d that is not provided. This is because retroactive processing such as rolling is performed from a wire having a uniform diameter. Therefore, the screw nail 1 indicated as a whole by reference numeral 1 is a mild steel material suitable for retrofit processing. The head 4 is not shown as a countersunk head in this example, but a cross groove for fitting a Phillips screwdriver is provided on the end face of the head.

The screw thread 3 is a triangular screw, a right-handed screw, and the screw bottom is a flat screw shaft portion 2c.

The groove 5 provided for providing the cutting edge 2a4 has a shape twisted in the same direction as the twist direction of the thread 3. The lead of the groove 5 is much larger than the lead of the thread 3, and the thread is cut off by the portion of the groove 5. However, the groove 5 is a V-shaped cross section having a linear shape in processing.

The surface formed by the edge of one surface of the groove 5 forming the cutting edge 2a4 is a rake surface 5a (see FIG. 2).

The rake face 5a, which is one side of the groove 5, is an arrow in the direction of rotation of the screw nail passing through the cutting edge 2a4 toward the opposite side of the drawing sheet with respect to the plane perpendicular to the drawing sheet and passing through the tip cutting edge 2a2 as seen in FIG. The surface is inclined in the opposite direction to K. The angle at which the groove surface 5c, which is a flat surface crossing the rake surface 5a, faces the groove bottom 5b is constant (see FIG. 5). This is because the shape of the groove 5 is determined by forming the groove 5 by cutting using an angle cutter.

As shown in FIGS. 3 and 4, the surface intersecting the rake face 5a with the cutting edge 2a4 (consisting of the tip cutting edge 2a2 and the retreating cutting edge 2a3) as a flank 2a6. As shown in FIG. 5, when Q is a circle passing through the retreating cutting edge 2a3 centered on one point C 'on the center line C of the shaft portion 2, the flank 2a6 gradually becomes a circle when viewed clockwise from the retreating cutting edge 2a3. The curved surface is in the direction from Q to the point C ′. This curved surface may be a flat surface. When the flank is flat, a straight line (not shown) passing through the retreating cutting edge 2a3 and contacting the circle Q on the paper surface of FIG. 5 and a straight line inclined toward the inside of the circle Q with respect to the reciprocating cutting edge 2a3 (see FIG. 5). The angle formed by (not shown) is the clearance angle of the retreating cutting edge 2a3. Similarly, the angle between the straight line r connecting the point C ′ and the retreating cutting edge 2a3 and the straight line S connecting the retreating cutting edge 2a3 and the groove bottom 5b (line cutting the rake face 5a) is the rake angle α in this cross section.

As shown in FIG. 6, the cutting edge 2a2 similarly has a flank 2a7 and a rake face 5a with respect to the cutting edge 2a3. The tip cutting edge 2a2 has a rake angle β between the rake face β and a clearance angle γ between a straight line 2a8 that is in contact with the flank 2a7 at the tip cutting edge 2a2 and a line 2a9 that is perpendicular to the line C2 parallel to the center line C. ing.

The flank 2a7 may be a plane passing through the straight line 2a8, or may be a curved surface in contact with the straight line 2a8 at the tip cutting edge 2a2 as shown in FIG.

The shape of the peripheral surface of the tip portion 2a of the shaft portion will be described. As shown in FIG. 5, the cross section of the distal end portion 2a has a shape close to an ellipse having a major axis in the vertical direction and a minor axis in the horizontal direction (upper focal point C ′, lower focal point not shown). In the case of an ellipse, the point C ′ is one of the focal points. The receding cutting edge 2a3 is provided on the outer circumference in the major axis direction of the ellipse. This is because the distal end cutting edge 2a2 is radiated from the distal end 2a1 at a position corresponding to the point C ', and the cutting edge 4 has a flank 2a6, 2a7 in the circumferential direction. Accordingly, the flank surfaces 2a6 and 2a7 are twisted surfaces that increase in diameter in the clockwise direction toward the paper surface in FIG. 4, and the twist gradually decreases toward the screw shaft portion 2c and comes into contact with the screw shaft portion 2c. .

When the screw nail 1 of the embodiment of the present invention configured as described above was screwed into the particle board and decora board with a cordless screwdriver, the screw nail was screwed in as soon as it started rotating, and the screw nail never fell down. .

The screw nails in the conventional example often fall on the particle board or decora board regardless of the presence or absence of grooves in the vertical direction, and cannot be screwed in. The cumulative number of rotations, not the rotation speed, is much higher than when screwed into natural wood.

This is considered as follows. In the conventional example, the cone angle at the tip of the shaft portion of the screw nail (the tip is close to the cone but bulges more than the cone. See the embodiment) is about 20 degrees. And also in the case of a groove, the cutting blade is constituted by being inclined with respect to the generatrix at the tip.

When rotation is applied with the conventional screw nails, the surface of the particle board and decora board is slightly recessed when the tip is pressed against the surface of the particle board and decora board. Even if rotation is given to the screw nail in this state, the peripheral speed of the maximum diameter portion of the tip contacting the board is small because the maximum rotation speed of the cordless driver is about 500 to 600 rotations per minute. In the case of mild steel, the cutting speed is 20 m / mn.

The cone angle of the tip of the shaft portion of a commercially available screw nail (screw portion outer diameter 3.1 mm) of the conventional example is about 20 degrees. Now, this screw nail is placed at a right angle to the particle board and decora board and is pushed by 0.5mm to send the screw nail. When the particle board and decora board are dented 0.5mm, the axis of the screw nail The shaft diameter at the position of 0.5 mm from the head of the head toward the head is 0.173 mm. As for the peripheral speed in this diameter portion, when the rotational speed of the cordless screwdriver is 600 revolutions per minute, the cutting speed is 0.173 × 3.142 × 600 = 326 mm / mn = 0.326 m / mn. In this case, since the cutting speed is slow, it cannot be cut or it takes time to cut. It is difficult to support a screw nail for a long time with a cordless screwdriver, and the screw nail falls down with the force of pushing the cordless screwdriver.

In the embodiment of the present invention, it is assumed that the tip cutting edge 2a2 is at an angle of 5 degrees with respect to a plane perpendicular to the tip 2a1 of the shaft portion 2 and passing through the tip 2a1. When the particle board or decora board is pushed at a right angle with respect to the particle board or decora board and fed to the screw nail 1 and fed 0.5 mm, the particle board or decora board is dented 0.5 mm, the shaft tip 2a1 to 0 The distance from the shaft center line C to the point where the plane perpendicular to the shaft center line C cuts the tip cutting edge 2a2 at the position facing the .5 millimeter head 4 is 1.76 millimeters. The peripheral speed at this point is 1.76 × 2 × 3.142 × 600 = 6631 mm / mn = 6.63 m / mn when the rotational speed of the cordless driver is 600 rpm. Even if this is not sufficient as the cutting speed, it is remarkably improved as compared with the conventional example. Therefore, when screwing the screw nail of the embodiment of this device into a particle board, decora board, etc. using a cordless screwdriver, it is considered that the screw nail does not fall down and starts screwing straight.

From the above-mentioned point, it is preferable that the angle formed by the tip cutting edge 2a2 with respect to the plane perpendicular to the shaft portion 2 is about 20 degrees. When this angle is 45 degrees, the diameter expansion ratio in the maximum diameter portion of the cutting action range of the tip cutting edge 2a2 with respect to the cutting feed of the screw nail to the particle board is about twice the cutting feed, and the cutting speed The increase rate of becomes smaller. Even in this case, the cutting speed is considerably faster than the conventional example.

1 ... Screw nails
2 ... Shaft 2a ... Tip 2a1 ... Shaft tip 2a2 ... Cutting edge 2a3 ... Retracting cutting edge 2a4 ... Cutting blade 2a5 ... Projection 2a6, 2a7 ... Flank 2a8 ... Straight line 2a9 ... Wire 2b ... Yoke 2c ... Screw Shaft 2d ... head side shank 3 ... thread 4 ... head 5 ... groove 5a ... rake face 5b ... groove bottom 5c ... groove face C ... center line C '... one point C2 ... line Q ... circle S ... straight line β ... Rake angle γ ... clearance angle

Claims (1)

In a screw nail with a thread around the cylindrical shaft,
The tip of the shaft portion is tapered, and a cutting edge is provided at the tip of the shaft portion in the radial direction from the center. The cutting blade is provided at a shallow angle in the range of 0 to 45 degrees with respect to a plane perpendicular to the shaft portion. The tip cutting blade and the tip cutting blade are formed by providing a receding cutting edge in the axial direction or a groove inclined with respect to the axial direction from the end on the outer peripheral side of the shaft portion toward the head. A screw nail characterized in that is provided from the tip of the shaft portion toward the head side of the screw nail.