Tail-cutting self-tapping screw

Abstract

The utility model relates to a screw, and discloses a tail-cutting self-tapping screw which comprises a nut part, a screw rod part, a first tail-cutting opening and a second tail-cutting opening. When self-tapping begins, the piercing section abuts against the surface of a workpiece, the screw rotates in the screwing-in direction, the first cutting edge of the main cutting part makes contact with the surface of the workpiece firstly for punching, and then the second cutting edge of the main cutting part and the auxiliary cutting part cut and trim the inner wall of a hole. In the self-tapping process, chippings generated by the main cutting part are removed outwards through the second tail cutting opening along the outer thread. And chippings generated by the auxiliary cutting part are cleaned outwards along the external threads through the first tail cutting opening. The utility model has the beneficial effects that the chip removal is smoother in the use process, and the use is more convenient and labor-saving.

Description

Technical Field

[0001] The utility model relates to a screw, in particular to a self-tapping screw with a cut tail. Background Art

[0002] Ordinary self-tapping screws are generally used on workpieces with holes drilled on the surface. That is, when the self-tapping screw is screwed into the hole, a matching internal thread is tapped on the inner wall of the hole. Cut-end self-tapping screws are generally used on workpieces without holes on the surface. That is, the cut-end self-tapping screws must first drill a hole on the surface of the workpiece, and then tap the matching internal thread on the inner wall of the hole. Compared to ordinary self-tapping screws, cut-end self-tapping screws require much more debris removal during use due to the multiple hole-drilling steps. Existing cut-end self-tapping screws are prone to poor chip removal during use, making screwing in more difficult or even impossible. Utility Model Content

[0003] The present application provides a tail-cutting self-tapping screw, which can solve the problems raised in the background technology.

[0004] In this application, a self-tapping screw with a cut tail is provided, comprising

[0005] Nut part;

[0006] The screw portion comprises a first section being a threaded section connected to the nut portion, and a second section being a piercing section without external threads; a transition section being located on the side of the threaded section close to the piercing section, wherein the diameter of the external threads of the transition section decreases as it approaches the piercing section;

[0007] The first cutting tail opening is provided at the portion of the piercing section and the threaded section close to the piercing section, and the piercing section has a main cutting portion and a secondary cutting portion on either side of the first cutting tail opening;

[0008] The second cutting tail opening is arranged at the part of the piercing section and the threaded section close to the piercing section and on the side opposite to the first cutting tail opening; when the screw part is screwed in along the external thread of the threaded section, the self-tapping point cyclically passes through the main cutting part, the second cutting tail opening, the auxiliary cutting part and the first cutting tail opening.

[0009] Furthermore, the secondary cutting portion is extended to a portion of the threaded section close to the piercing section.

[0010] Furthermore, the external thread of the transition portion is thicker than the remaining external thread of the threaded section.

[0011] Furthermore, the minor diameters of the external threads on the threaded segments are equal.

[0012] Furthermore, the nut portion is one of a slotted hole, a cross hole, an inner hexagonal hole or an outer hexagonal hole.

[0013] Furthermore, the nut portion is integrally provided with a gasket.

[0014] In summary, in the present application, a self-tapping screw with a cut tail includes a nut portion, a screw portion, a first cut tail opening, and a second cut tail opening. At the beginning of self-tapping, the piercing section is pressed against the surface of the workpiece, and the screw rotates in the screwing direction. The first cutting edge of the main cutting portion first contacts the surface of the workpiece to punch a hole, and the second cutting edge of the main cutting portion and the auxiliary cutting portion then cut and trim the inner wall of the hole. During the self-tapping process, the debris generated by the main cutting portion is cleared out along the external thread through the second cut tail opening; the debris generated by the auxiliary cutting portion is cleared out along the external thread through the first cut tail opening. The beneficial effects are: chip removal is smoother during use, and it is more convenient and labor-saving to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology will be described below.

[0016] Figure 1 This is a schematic diagram of the structure of this application;

[0017] Figure 2 This is a schematic diagram of the first cutting end;

[0018] Figure 3 This is a schematic diagram of the second cutting tail.

[0019] In the figure,

[0020] 1. Nut part; 1a. Gasket;

[0021] 2. Screw part; 2a. Threaded section; 2a1. Transition section; 2b. Penetration section;

[0022] 3. First cutting edge; 3a. Main cutting portion; 3a1. First cutting edge; 3a2. Second cutting edge; 3b. Secondary cutting portion;

[0023] 4. Second cut of the tail. DETAILED DESCRIPTION

[0024] The following is further explained in conjunction with the accompanying drawings. Unless otherwise defined, the technical terms or scientific terms used in this disclosure should have the usual meanings understood by people with ordinary skills in the field to which this disclosure belongs. The "first", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprising" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0025] See also Figure 1 、 Figure 2 and Figure 3 A self-tapping screw with a cut tail includes a nut portion 1, a screw portion 2, a first cut tail opening 3 and a second cut tail opening 4.

[0026] The nut portion 1 can be one of the conventional slotted holes, cross holes, internal hexagonal holes or external hexagonal holes. The nut portion 1 can be integrally provided with a gasket 1a or not, and the gasket 1a can be inserted during subsequent use.

[0027] The screw portion 2 is divided into two sections. The first section is the threaded section 2a, which has external threads on its surface and its first end is integrally connected to the nut portion 1. The second section is the piercing section 2b, which lacks an external nut and has a pointed second end, integrally connected to the second end of the threaded section 2a. The side of the threaded section 2a near the piercing section 2b is a transition section, where the diameter of the external threads decreases as it approaches the piercing section 2b.

[0028] The first cutting tail opening 3 is arranged at the piercing section 2b and the part of the threaded section 2a close to the piercing section 2b, that is, when the first cutting tail opening 3 cuts the tail on the screw part 2, it passes through the entire piercing section 2b and then passes through the part of the threaded section 2a close to the piercing section 2b.

[0029] The piercing section 2b is provided with a main cutting portion 3a and a secondary cutting portion 3b on either side of the first cutting tail 3. That is, at the beginning of self-tapping, there is no hole on the workpiece surface (for example, the workpiece is wood), the piercing section 2b is pressed against the workpiece surface, and the screw is rotated in the screwing direction. The first cutting edge 3a1 of the main cutting portion 3a first contacts the workpiece surface to punch the hole, and the second cutting edge 3a2 of the main cutting portion 3a and the secondary cutting portion 3b then cut and trim the inner wall of the hole.

[0030] The second cutting tail opening 4 is also provided at the portion of the piercing section 2 b and the threaded section 2 a close to the piercing section 2 b , and the second cutting tail opening 4 is on the side opposite to the first cutting tail opening 3 .

[0031] As the screw portion 2 is screwed in along the external threads of the threaded section 2a, the tapping point cyclically passes through the primary cutting portion 3a, the secondary cutting portion 4, the secondary cutting portion 3b, and the first cutting portion 3. Specifically, depending on the direction of rotation of the external threads, the tapping point can be arranged such that: the primary cutting portion 3a is on the first side of the first cutting portion 3 and the secondary cutting portion 3b is on the second side of the first cutting portion 3, or the primary cutting portion 3a is on the second side of the first cutting portion 3 and the secondary cutting portion 3b is on the first side of the first cutting portion 3. During the tapping process, debris generated by the primary cutting portion 3a is cleared outward along the external threads through the second cutting portion 4; debris generated by the secondary cutting portion 3b is cleared outward along the external threads through the first cutting portion 3.

[0032] Optionally, the auxiliary cutting portion 3b is further extended to the transition portion, thereby improving the cutting and trimming effect of the auxiliary cutting portion 3b and making the processing of the first cutting tail 3 more convenient.

[0033] Optionally, the external thread of the transition portion is thicker than the remaining external threads on the threaded section 2a. In this way, the strength of the external thread on the transition portion is improved, making it more convenient and labor-saving when starting tapping.

[0034] Optionally, the minor diameters of the external threads on the threaded section 2a are equal. Accordingly, the above-mentioned "the diameter of the external threads of the transition portion decreases as it approaches the piercing section 2b" means that the major diameter of the external threads of the transition portion decreases as it approaches the piercing section 2b. This facilitates thread processing.

Claims

1. A self-tapping screw with a cut tail, characterized in that: include Nut portion (1); The screw portion (2) comprises a first section being a threaded section (2a) connected to the nut portion (1), and a second section being a piercing section (2b) without external threads; a side of the threaded section (2a) close to the piercing section (2b) being a transition section, wherein the diameter of the external threads of the transition section decreases as it approaches the piercing section (2b); The first cutting tail opening (3) is provided at the portion of the piercing section (2b) and the threaded section (2a) close to the piercing section (2b), and the piercing section (2b) comprises a main cutting portion (3a) and a secondary cutting portion (3b) on both sides of the first cutting tail opening (3); The second cutting tail opening (4) is arranged at the portion of the piercing section (2b) and the threaded section (2a) close to the piercing section (2b) and on the side opposite to the first cutting tail opening (3); when the screw portion (2) is screwed in along the external thread of the threaded section (2a), the self-tapping point cyclically passes through the main cutting portion (3a), the second cutting tail opening (4), the auxiliary cutting portion (3b) and the first cutting tail opening (3).

2. The self-tapping screw with a cut tail according to claim 1, characterized in that: The auxiliary cutting portion (3b) is further extended to the portion of the threaded section (2a) close to the piercing section (2b).

3. The self-tapping screw with a cut tail according to claim 1, characterized in that: The external thread of the transition portion is thicker than the remaining external thread of the threaded section (2a).

4. The self-tapping screw with a cut tail according to claim 1, characterized in that: The minor diameters of the external threads on the threaded section (2a) are equal.

5. The self-tapping screw with a cut tail according to claim 1, characterized in that: The nut portion (1) is one of a slotted hole, a cross hole, an inner hexagonal hole or an outer hexagonal hole.

6. The self-tapping screw with a cut tail according to claim 1, characterized in that: The nut portion (1) is integrally provided with a gasket (1a).

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