KR20090017318A - Tapping screw - Google Patents

Abstract

A tapping screw is provided to form grooves at a portion from a point at which a screw thread starts to the fifth screw thread such that friction is not generated at the groove so as to remarkably reduce tightening torque. A tapping screw(10) includes a head(11), a screw part(12) and a tip(13). The tapping screw has a plurality of grooves formed at a portion from the tip to a part of the screw part. The grooves have a gentle slope and a steep slope. The steep slope is formed front on the basis of a screw tightening direction.

Description

Tapping screw

The present invention relates to a tapping screw that is fastened while forming a female thread, and more particularly, to a tapping screw that can reduce a tightening torque by digging a plurality of grooves of a proper length at a distal end of a threaded portion and suppressing screw loosening after fastening. .

Conventionally developed for reducing the tightening torque, a "tab screw" having three arc-shaped missing portions at the tip of the screw portion has been disclosed in Japanese Patent No. 3020904.

The prior art has a head portion at the base end of the columnar portion and a truncated cone portion at the tip, and has a circular male screw formed at the columnar portion. The plurality of male threads formed in the columnar portion adjacent to the truncated conical portion form a plurality of expansion top portions projecting slightly in the radial direction from the outer diameters of all the other male thread mounts, and at the same time as the male thread portions existing between the respective expansion top portions. The height of the remaining male thread mountain which forms a screw thread missing part and each missing part between each expansion top part is set lower than the height of all the other male thread mountains mentioned above.

However, the prior art has a problem of reducing the tightening torque when screwing, there is a problem that can not prevent the screw loosening due to external factors such as shock or vibration of the device after tightening.

The present invention is to solve the conventional problems as described above, it is an object of the present invention to reduce the screw tightening torque when screwing and at the same time provide a screw that is prevented from loosening the screw after screwing.

The present invention for achieving the above object

A head portion, a screw portion, and a truncated truncated tip are provided, wherein a plurality of grooves are formed from the truncated truncated tip to a part of the threaded portion, the groove having a mild slope and a steep slope and the steep slope is based on a screw tightening direction. There is a characteristic formed by the front.

The groove has another feature that is formed by forming the depth to a depth of 1/2 or more of the screw thread height.

The groove is five and there is another feature formed to maintain equidistant from each other.

In the present invention having the above characteristics, the most frictional force is generated at the tip of the male screw that is driven while generating the female screw when the screw is tightened. Since this does not occur, the tightening torque is remarkably reduced when the screw is tightened, and is formed between the steep slope and the screw top part connected thereto when a force to rotate in the release direction due to the impact or vibration of the device is applied by the steep slope of the groove. Since the reverse rotation of the screw is suppressed by the tip portion is to prevent the loosening.

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

1 is a front view showing a preferred embodiment according to the present invention, Figure 2 is a partially enlarged view of Figure 1, Figure 3 is a cross-sectional view taken along the line A-A of FIG.

As shown, the tab screw 10 is divided into a head portion 11, a columnar threaded portion 12, and a truncated truncated tip portion 13, and a groove 20 is formed thereon from the truncated truncated tip portion 13. It is.

The groove 20 is preferably threaded up to five times from the bottom, but more or less may be possible. In addition, the groove 20 is formed of a steep slope 21 and a mild slope 22, the tightening direction is based on the direction of the arrow 30 of Figure 3 in the front of the steep slope 21, the rear is a mild slope ( 22).

It is preferable that the depth of the groove 20, that is, the boundary point between the steep inclined plane and the mild inclined plane is at least 1/2 of the thread height.

The grooves 20 may be two, three, five, or the like, but most preferably, five grooves are formed.

The groove 20 formed as described above generates the most frictional force at the tip of the male screw that is driven while generating the female screw when the screw is fastened, and the groove 20 is formed from the beginning to the fifth thread, as shown in FIG. 3. Since the friction does not occur in this formed portion, the friction area is reduced, and thus, the tightening torque is significantly reduced when the screw is tightened.

In addition, since the mildly inclined surface 22 of the groove is connected to the screw top portion 12a which generates a lot of friction, the mildly inclined surface 22 becomes a mold for guiding the screw top portion 12a, and the screw top portion 12a creates a female screw portion. While smoothing the progress of the screw top portion (12a) while being pushed to reduce the tightening torque of the screw.

In addition, the steep inclined surface 21 of the groove has a shape that follows the screw top portion 12a when the screw rotates in the direction of the arrow 30 in FIG. 3, but has no effect, but the impact of the device to which the screw is fastened. When the force to rotate in the loosening direction, i.e., the direction opposite to the arrow in FIG. 3, is caused by vibration or the like, the screw is reversed by the tip 21a formed between the steep slope 21 and the screw top portion 12a. Since rotation is suppressed, the loosening is to prevent the role.

The present invention is an improvement on the conventional tapping screw that has been used for a long time and can be used in the same way as in the prior art, so there is no problem in industrial use.

1 is a front view of a tapping screw according to the invention

2 is an enlarged partial view of FIG.

3 is a cross-sectional view taken along the line A-A of FIG.

<Code Description of Main Parts of Drawing>

10 is a tapping screw, 12 is a thread, 13 is a truncated tip, 20 is a groove,

21 is a steep slope, 22 is a mild slope

Claims (3)

A head portion, a screw portion, and a truncated truncated tip are provided, wherein a plurality of grooves are formed from the truncated truncated tip to a part of the threaded portion, the groove having a mild slope and a steep slope and the steep slope is based on a screw tightening direction. Tapping screw, characterized by forming on the front. The method of claim 1, And the groove is formed to a depth of 1/2 or more of the thread height of the threaded portion. The method of claim 1, The groove is five and the tapping screw, characterized in that to maintain the same distance from each other.

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