JP2010190269A - Tapping screw for hard wood - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tapping screw for hard wood, easily screwed into thick and hard wood with small screwing force and having sufficient fastening force. <P>SOLUTION: The tapping screw is provided with a parallel thread 5 on an outer periphery of a shank 1, in which a conical tapered portion 2 is provided at an end and a head 3 having an engagement portion for a rotary tool is provided at the other end. The tapered portion 2 is provided with a tip introducing thread 4 and the tip introducing thread 4 connects with the parallel thread 5. A plurality of protrusions 6, 6 radially protruding and extending in a longitudinal direction without parting the parallel thread 5 are provided on a tip part 1a of the shank 4 adjacent to the tapered portion 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hardwood tapping screw suitable for screwing into thick and hard wood.

  As a wood tapping screw, a conical taper portion is provided at one end, and a parallel thread is provided on the outer periphery of a shaft portion provided with a head having an engaging portion of a rotary tool at the other end. It is known in the prior art that a tip introduction thread is provided in the part, and the tip introduction thread is continuous with the parallel thread.

  For example, when fixing a relatively thick and hard floor material to a girder by using the above-described conventional wood tapping screw, the tip introduction screw thread is rotated while being pushed strongly in order to bite into the wood part. It is necessary to tapping the female thread with the tip-introducing thread while expanding the fiber of the wood part with the conical taper part, so that the parallel thread is screwed into the female thread until the self-advancing action of the screw occurs. Rotational resistance is large and seizure is likely to occur. Further, in the case of hard wood, there is a problem that cracking occurs due to a large pushing force.

  In order to solve the above problems, a wood tapping screw provided with a plurality of protrusions having a reamer function at a tip portion of the shaft portion adjacent to the conical tapered portion has been proposed (Patent Literature). 1-3).

  These wood tapping screws extend as the ridges are twisted in the axial direction and function as a reamer when screwed, so that the fibers of the timber are unwound and softened by the ridges, and even small screws can be screwed into hard wood. There is an advantage that the parallel thread can be screwed in by force.

  However, since each of the protrusions of the wood tapping screw is provided by dividing the tip introduction thread of the conical taper portion and the parallel thread of the tip portion of the shaft portion, There is a drawback that the parallel thread is not correctly screwed into the female thread tapped by the tip-introducing thread, and therefore, not only the rotational resistance until the self-advancing action of the screw is caused by the parallel thread but also the female thread is There was also a disadvantage that sufficient tightening force could not be obtained due to breakage.

JP 2003-42122 A Japanese Utility Model Publication No.5-14055 Japanese Utility Model Publication No. 63-128308

  An object of the present invention is to provide a tapping screw for hard wood that solves the above-described problems and can be easily screwed into a thick and hard wood with a small screwing force, thereby obtaining a sufficient tightening force. .

  In order to solve the above problems, the present invention provides a parallel thread on the outer periphery of a shaft portion provided with a conical taper portion at one end and a head portion having an engaging portion of a rotary tool at the other end. A tip introduction thread is provided in the taper portion, and the tip introduction screw thread is a tapping screw continuous to the parallel thread, and is provided at a tip portion of the shaft portion adjacent to the taper portion. A hardwood tapping screw comprising a plurality of protrusions protruding in a radial direction and extending in a longitudinal direction without dividing the parallel thread.

  In the above configuration, the protrusion is preferably configured to extend in the longitudinal direction crossing the parallel thread at the distal end portion of the shaft portion. It is good also as a structure formed in this.

  Moreover, although the height of the said protrusion is set as the structure substantially equal to the height of the said parallel thread, you may make it below the height of the said parallel thread.

  Furthermore, although it is preferable that the protrusion is configured to be twisted with respect to the axis of the shaft portion and extend in the longitudinal direction, the protrusion may be configured to extend in the longitudinal direction in parallel with the axis of the shaft portion.

  The tapping screw of the present invention has a configuration in which the protrusion protruding radially in the tip portion of the shaft portion adjacent to the taper portion and extending in the longitudinal direction does not divide the parallel thread provided on the shaft portion. From the above, the tip-introducing screw thread provided in the taper part is bitten into the wood part, and the female thread is tapped, and then the ridge having the reamer function loosens the fiber of the wood part and softens the parallel parts. The threading resistance of the thread can be reduced, and the parallel thread is continuous with the tip-introducing thread, so that the tapped female thread can be correctly screwed and the parallel thread can be reduced with a small screwing force. It can be screwed in to produce a self-advancing action of the screw. Therefore, even hard wood can be easily screwed with a small screwing force, and a sufficient tightening force can be obtained.

It is a front view of the tapping screw for hard wood which concerns on Example 1 of this invention. It is a left side view same as the above. It is a right side view same as the above. It is a principal part enlarged view of FIG. FIG. 3 is an enlarged view of a main part of FIG. 2. It is a principal part enlarged view of FIG. It is a front view of the tapping screw for hard wood which concerns on Example 2 of this invention. It is a left side view same as the above. It is a right side view same as the above.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 to 3 show a tapping screw for hard wood according to a first embodiment of the present invention. A shaft portion 1 is an elongated cylindrical body having a predetermined diameter, and a conical tapered portion 2 is provided at one end. The other end is provided with a head 3 having an engaging portion (not shown) for the rotary tool. The taper portion 2 is provided with a tip introduction thread 4, a parallel thread 5 is provided on the outer periphery of the shaft portion 2, and the parallel thread 5 provided at the tip portion 1 a of the shaft portion 1 is the tip introduction screw thread 4. The structure formed continuously is the same as a conventional wood tapping screw.

  The tapping screw according to the present invention protrudes in the radial direction at the tip end portion 1a of the shaft portion 1 adjacent to the tapered portion 2, and the two protrusions 6 and 6 extending in the longitudinal direction are 180 degrees out of phase in the circumferential direction. Projected. The ridges 6 and 6 have a reamer function, and as shown in FIGS. 4 to 6, are fin-shaped and have a height substantially equal to the height of the parallel thread 5 and a shaft portion. It intersects with the parallel thread 5 provided in the upper tip portion 1a and twists in the axial direction and extends in the longitudinal direction, but the parallel thread 5 is not divided. That is, the parallel thread 5 itself maintains a continuous form. In addition, in order to ensure the continuity of the parallel thread 5, it is desirable that the height of the protrusions 6, 6 is equal to or less than the height of the parallel thread 5.

  By providing the protrusions 6 and 6 as described above, the tip of the conical taper portion 2 is pressed against the wood of the object to be fastened and rotated while pushing the shaft portion 1 with a rotary tool (not shown) engaged with the head 3. Then, the tip-introducing screw thread 4 bites into the wood part and taps the female screw, and then the ridges 6 and 6 having a reamer function loosen and soften the fiber of the wood part, and the subsequent shaft part 1 to reduce the screwing resistance of the parallel thread 5 provided at the tip portion 1a. Moreover, since the parallel thread 5 is continuous with the tip introduction thread 4 and is not divided by the ridges 6, 6, the parallel thread 5 is correctly screwed into the female screw tapped by the tip introduction thread 4, and the parallel thread The thread 5 can be screwed in with a small screwing force to produce a self-advancing action of the screw. Therefore, even hard wood can be easily screwed with a small screwing force, and a sufficient tightening force can be obtained.

  FIGS. 7 to 9 show a tapping screw for hard wood according to a second embodiment of the present invention. The same components as those of the tapping screw of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the tapping screw according to the second embodiment, the ridges 7, 7 provided on the tip portion 1 a of the shaft portion 1 are parallel threads provided on the tip portion 1 a of the shaft portion 1 like the ridges 6, 6 of the first embodiment. 5 and does not extend in the longitudinal direction, and has a length approximately equal to the screw pitch in the middle of the parallel thread 5.

  Even when such protrusions 7 and 7 are provided, the same effect as in Example 1 can be obtained, and even a hard wood can be easily screwed with a small screwing force, and a sufficient tightening force can be obtained.

  The tapping screw of the present invention is suitable for fixing a relatively thick floor material made of hard wood to a wood of a girder by screwing.

DESCRIPTION OF SYMBOLS 1 Shaft part 1a The front-end | tip part of the shaft part 1 2 Conical taper part 3 Head part 4 Tip introduction thread 5 Parallel thread 6, 7 Projection

Claims (5)

A conical tapered portion is provided at one end, and a parallel thread is provided on the outer periphery of the shaft portion provided with a head having an engaging portion of the rotary tool at the other end, and a tip introduction thread is provided in the tapered portion. And the tip introduction thread is a tapping screw continuous with the parallel thread,
A hardwood tapping pin characterized in that a plurality of protrusions protruding in a radial direction and extending in a longitudinal direction without dividing the parallel thread are provided at a tip portion of the shaft portion adjacent to the taper portion. screw.   The tapping screw for hard wood according to claim 1, wherein the protrusions extend in the longitudinal direction crossing the parallel threads.   2. The hardwood tapping screw according to claim 1, wherein the protrusion is formed in the middle of the parallel thread with a length substantially equal to a screw pitch.   The tapping screw for hard wood according to claim 1, 2 or 3, wherein the height of the ridge is substantially equal to the height of the parallel thread.   The tapping screw for hard wood according to claim 1, 2, or 3, wherein a height of the protrusion is equal to or less than a height of the parallel thread.

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