TWI717215B - A self-tapping screw - Google Patents

Abstract

A self-tapping screw is provided to overcome the problem of the conventional self-tapping screw forming a bulge or crack on the object surface after being screwed into the object. The self-tapping screw includes a rod having a predetermined length and at least one screw teeth part helically formed on and extended along the rod from the first end to the second end of the rod. The self-tapping screw further includes a tapping part located at the first end of the rod. The self-tapping screw further includes a cap located at the second end of the rod and having a surface and a connection surface. A thickness is between the surface and a connection surface. The maximum outer diameter of the connection surface and the periphery of the cap has a diameter difference, so that a lip forms between the periphery of the cap and the outside of the connection surface. Several cutting edges are located around the connection surface. Each of the several cutting edges has a top. Each of two sides of the top has a cutting arc and an inclined plane.

Description

Self-tapping screws

The invention relates to a self-tapping screw, especially a head design of a self-tapping screw.

Please refer to Figure 1, which is a conventional self-tapping screw 9. The conventional self-tapping screw 9 has a cap 91, a screw 92, and a drill 93. A threaded portion 94 spirally surrounds the screw 92. On the outer surface, the head 91 has a top 95 and a bottom 96. The diameter of the head 91 decreases from the top 95 to the bottom 96, so that the head 91 is almost curved, making the conventional The self-tapping screw 9 can be locked into the locked object more easily and smoothly.

As mentioned above, when the conventional self-tapping screw 9 is drilled and locked, the threaded portion 94 can guide the debris generated during the tapping process to the direction of the cap head 91, as the screw is locked As the length of entry increases, the amount of these debris also increases and accumulates on the periphery of the keyhole, so that the cap 91 cannot be completely buried in the object to be locked, causing the surface of the object to be locked to bulge. Locking the self-tapping screw 9 into the locked object will also cause cracks around the keyhole. These protrusions and cracks will not only scratch the worker or user, but also affect the overall appearance of the locked object.

In view of this, the conventional self-tapping screws do still need to be improved.

To solve the above problems, the purpose of the present invention is to provide a self-tapping screw, which can Cut the debris to make it easy to remove, so as to avoid the accumulation of debris and cause the surface of the locked object to bulge or produce cracks.

The directionality described in the full text of the present invention or its similar terms, such as "front", "rear", "left", "right", "up (top)", "down (bottom)", "inner", "outer" , "Side", etc., mainly refer to the directions of the attached drawings. The directional or similar terms are only used to help explain and understand the embodiments of the present invention, and are not used to limit the present invention.

The elements and components described in the full text of the present invention use the quantifiers "one" or "one" for convenience and to provide the general meaning of the scope of the present invention; the present invention should be interpreted as including one or at least one, and single The concept of also includes the plural, unless it clearly implies other meanings.

The approximate terms such as "combination", "combination" or "assembly" mentioned in the full text of the present invention mainly include the types that can be separated without destroying the components after being connected, or the components can not be separated after being connected, which are common knowledge in the field Those can be selected based on the materials of the components to be connected or assembly requirements.

The self-tapping screw of the present invention includes: a rod body having a predetermined length, the rod body is provided with at least one thread part, the thread part starts from the first end of the rod body to the second end Spirally surrounding; a tapping portion located at the first end of the rod body; and a cap head located at the second end of the rod body, the cap head has a surface and a connecting surface, the surface and the connecting surface There is a thickness between the maximum outer diameter of the connecting surface and the peripheral edge of the cap head, so that a lip is formed between the peripheral edge of the cap head and the outer periphery of the connecting surface. Each of the cutting edges has a top, and two sides of the top are respectively provided with a cutting arc and a bevel; the plurality of cutting edges each have a first end and a second end, the first The ends are adjacent to the ends of the thread part but not connected to each other, and the second end extends to the peripheral edge of the cap head so that the second end of the cutting edge protrudes from the lip part.

Accordingly, the self-tapping screw of the present invention can be broken by the cutting edge of the cap head The chip cutting is refined to make it easy to remove the chips to prevent the chips from accumulating and being locked into the lock hole. Then the lip is used to screw the refined chips into the lock hole, which has the ability to lift the self Tapping screw cutting and destructive ability to improve the cutting efficiency of the screw, and can increase the bonding strength of the self-tapping screw when combined with the object to be locked, and can prevent the surface of the object from being raised or cracked.

Wherein, the thickness between the surface and the connecting surface is between 0.5 and 0.9 mm. In this way, it has the effect of improving the structural strength of the cap.

Wherein, the difference between the maximum outer diameter of the connecting surface and the peripheral diameter of the cap head is between 0.1 mm and 0.5 mm. In this way, it has the effect of improving the bonding strength between the self-tapping screw and the object to be locked.

Wherein, the broken face of the hat head has a central point, and the several cutting edges form equiangular and equidistant rings on the connecting surface, so that there is a center point between two adjacent cutting edges and the hat head. A first angle. In this way, it has the effect of improving the cutting efficiency of the screw.

Among them, the number of cutting edges is an even number and is set symmetrically. In this way, it has the effect of improving the locking balance of the screw.

Wherein, the number of the cutting edges is six, so that the angle between the cutting edges is 60 degrees. In this way, it has the effect of improving the cutting and damaging capabilities of the self-tapping screw for chips.

Wherein, the top of each cutting edge is a straight line, and the straight line is inclined and not parallel with respect to the axial centerline, so that the straight line has a second included angle when projected on the axial centerline. In this way, the cutting edge can cut and refine the chips first, which has the effect of avoiding the accumulation of chips.

Wherein, the second included angle is between 5 and 35 degrees. In this way, the cutting edge can cut and refine the chips first, which has the effect of avoiding the accumulation of chips.

Wherein, each of the cutting edges has a cutting arc surface and an inclined surface on both sides of the top, and the radial cross section of the rod body has an arc, and the normal line of the arc through the top forms a reference A first angle is formed between the cutting arc and the reference line, and a second angle is formed between the inclined surface and the reference line, and the second angle is greater than the first angle. In this way, the two sides of the cutting edge are asymmetrical to each other and form a claw shape, which has the effect of improving the cutting efficiency of the screw.

Wherein, the first angle is between 15-20 degrees. In this way, it has the effect of increasing the cutting force and destructive force of the screw.

Wherein, the second angle is between 30 and 37 degrees. In this way, it has the effect of improving the cutting efficiency of the screw.

〔this invention〕

1: Rod body

11: The first thread part

12: The first thread part

13: Chip flute

2: Invasion

3: hat head

3a: surface

3b: Connection surface

31: Lips

32: cutting edge

32a: first end

32b: second end

321: top

322: Cutting arc

323: Slope

G: lock slot

K: arc

M: center point

S: Baseline

T: thickness

W: diameter difference

X: axial centerline

θ1: The first included angle

θ2: second included angle

ø1: first angle

ø2: second angle

[Traditional]

9: Known self-tapping screws

91: Hat Head

92: screw

93: Drill

94: Threaded part

95: top

96: bottom

[Picture 1] A conventional self-tapping screw diagram.

[Figure 2] A perspective view of a preferred embodiment of the present invention.

[Figure 3] A front view of a preferred embodiment of the present invention.

[Figure 4] A sectional view taken along the line A-A in Figure 3.

[Figure 5] A sectional view taken along the line B-B in Figure 4.

[Figure 6] A partial enlarged view of the head part of a preferred embodiment of the present invention.

[Figure 7] Part C of Figure 4 is enlarged.

In order to make the above and other objects, features, and advantages of the present invention more obvious and understandable, the following is a detailed description of the preferred embodiments of the present invention with the accompanying drawings: Please refer to Figures 2 and 3 As shown, it is a preferred embodiment of the self-tapping screw of the present invention, which includes a rod body 1, a tapping portion 2 and a cap head 3. The tapping portion 2 is located at the first end of the rod body 1, the The cap head 3 is located at the second end of the rod body 1.

The rod body 1 has a predetermined length and has an axial centerline X. The rod body 1 has at least one thread portion, and the thread portion starts from the first end of the rod body 1 toward the second In this embodiment, the rod body 1 is provided with a first thread portion 11 and a second thread portion 12, and the first thread portion 11 is formed by the first end of the rod body 1. Starting to spiral around the second end, the second thread portion 12 is connected to the tail end of the first thread portion 11, and continues to spirally loop toward the second end, so that the first thread portion 11 and the The second threaded portion 12 is continuously wound around and protrudes on the outer surface of the rod body 1. Preferably, there may be a plurality of chip flutes 13 between each of the first screw thread portions 11, and the chip flutes 13 are continuously spirally surrounded and recessed on the outer surface of the rod body 1. , In order to discharge the debris generated in the process of tapping and drilling towards the direction of the cap head 3.

The penetration portion 2 is located at the first end of the rod body 1. The penetration portion 2 is the part that first contacts the object to be locked. The penetration portion 2 can be used to create an initial drilling hole on the surface of the object to be locked. Position the screw on the locked object to facilitate subsequent tapping. The tapping part 2 can be used for cutting tails or shovel tailings according to functions, and the present invention is not limited, and only needs to be convenient for the worker to use.

Please refer to Figure 3, the cap head 3 is located at the second end of the rod body 1 for the user to rotate and press the self-tapping screw to lock and screw into the locked object, the cap head 3 can be In order to learn various structures and shapes, the present invention is not limited. In this embodiment, the cap head 3 is illustrated by taking a circular shape as an example. The cap head 3 has a surface 3a and a connecting surface 3b. There is a thickness T between the surface 3a and the connecting surface 3b. The thickness T is preferably between 0.5 and 0.9 mm to improve the structural strength of the cap head 3. The surface 3a has a locking groove G which can be combined with a driving tool so that the worker can use The driving tool easily rotates the self-tapping screw to screw the cap head 3 into the object to be locked. The lock groove G can be a conventional slot or cross groove, which is not limited by the present invention for the convenience of the worker. The principle is sufficient; the connecting surface 3b is connected to the rod body 1, and the connecting surface 3b is generally arc-shaped and decreases in diameter toward the rod body 1, so that the self-tapping screw can be locked into the locked object more easily and smoothly.

Please refer to Figure 4, the maximum outer diameter of the connecting surface 3b and the cap head 3 The periphery has a diameter difference W, so that a lip 31 is formed between the periphery of the hat head 3 and the outer periphery of the connecting surface 3b. The diameter difference W is preferably between 0.1 and 0.5 mm to enhance the self-tapping The bond strength between the screw and the object to be locked. The connecting surface 3b is provided with a plurality of cutting edges 32 in the ring. The cutting edges 32 are used to destroy larger chips or fibers. The cutting edges 32 can form equiangular and equidistant rings. The connecting surface 3b has a first angle θ1 between the two adjacent cutting edges 32 and the center point M of the hat head 3. Preferably, the number of the cutting edges 32 is an even number and arranged symmetrically, so that the locking balance of the self-tapping screw can be increased. More preferably, the number of the plurality of cutting edges 32 is six, so that the first included angle θ1 between the plurality of cutting edges 32 is equal to 60 degrees, which can improve the chip cutting and chipping of the self-tapping screw Destructive ability and the effect of increasing the balance of screw locking.

Please refer to FIG. 5, each of the cutting edges 32 has a first end 32a and a second end 32b. The first end 32a is adjacent to the end of the second thread portion 12 but not connected to each other. The second end 32b extends to the periphery of the cap head 3, so that the second end 32b of the cutting edge 32 protrudes from the lip portion 31, which has the effect of increasing the cutting ability and making the surface of the object to be locked smoother.

Please refer to Fig. 6, each of the cutting edges 32 has a top portion 321. The top portion 321 can be a straight line or a curved line segment. The present invention is not limited, as long as it can effectively reduce the chip cutting. In this embodiment, the top portion 321 is a straight line, and the straight line is inclined and not parallel to the axial centerline X, so that when the straight line is projected on the axial centerline X, there is a second included angle θ2, and the second The angle θ2 is preferably between 5 and 35 degrees.

Referring to Figure 7, the cutting edge 32 has a cutting arc surface 322 and an inclined surface 323 on both sides of the top portion 321, respectively. The rod 1 has a circular arc K in the radial cross section, passing through the top portion 321 The normal line of the arc K forms a reference line S, the cutting arc surface 322 and the reference line S have a first angle ø1, the inclined surface 323 and the reference line S have a second angle ø2, the The second angle ø2 is greater than the first angle ø1, so that the two sides of the cutting edge 32 are asymmetrical to each other and form a claw shape to improve cutting efficiency. Preferably, the first angle ø1 is between 15 and 20 degrees, The second angle ø2 is between 30 and 37 degrees.

In summary, the self-tapping screw of the present invention can use the cutting edge of the cap head to cut and refine the chips, so that the chips can be easily removed, so as to prevent the chips from accumulating and being locked into the lock hole , And then use the lip to screw the refined chips into the key hole, which can improve the cutting and destruction ability of the self-tapping screw to improve the cutting efficiency of the screw, and can increase the coupling of the self-tapping screw to the object to be locked The combination of time and strength, and can prevent the surface of the locked object from bulging or cracking.

Although the present invention has been disclosed using the above-mentioned preferred embodiments, it is not intended to limit the present invention. Anyone who is familiar with the art without departing from the spirit and scope of the present invention may make various changes and modifications relative to the above-mentioned embodiments. The technical scope of the invention is protected. Therefore, the scope of protection of the invention shall be subject to the scope of the attached patent application.

1: Rod body

11: The first thread part

12: The first thread part

13: Chip flute

2: Invasion

3: hat head

3a: surface

3b: Connection surface

31: Lips

32: cutting edge

32a: first end

32b: second end

321: top

322: Cutting arc

323: Slope

Claims (11)

A self-tapping screw, comprising: a rod body with a predetermined length, the rod body is provided with at least one threaded part, the threaded part starts from the first end of the rod body and spirally surrounds the second end ; A tapping portion located at the first end of the rod body; and a cap head located at the second end of the rod body, the cap head having a surface and a connecting surface, the surface and the connecting surface have A thickness, the maximum outer diameter of the connecting surface and the peripheral edge of the cap head have a diameter difference, so that a lip is formed between the peripheral edge of the cap head and the outer periphery of the connecting surface, and a plurality of cutting rings are provided on the connecting surface Each cutting edge has a top, and two sides of the top have a cutting arc and a bevel; the cutting edges each have a first end and a second end, the first end is adjacent At the end of the thread part but not connected to each other, the second end extends to the periphery of the cap head, so that the second end of the cutting edge protrudes from the lip. Such as the self-tapping screw of claim 1, wherein the thickness between the surface and the connecting surface is between 0.5 and 0.9 mm. Such as the self-tapping screw of claim 1, wherein the difference between the maximum outer diameter of the connecting surface and the peripheral diameter of the cap head is between 0.1 and 0.5 mm. For example, the self-tapping screw of claim 1, wherein the fracture surface of the cap head has a center point, and the cutting edges form equiangular and equidistant rings on the connecting surface, so that the two adjacent cutting edges and There is a first included angle between the center points of the hat head. Such as the self-tapping screw of claim 1, where the number of cutting edges is an even number and is set symmetrically. Such as the self-tapping screw of claim 1, wherein the number of the cutting edges is six, so that the angle between the cutting edges is 60 degrees. Such as the self-tapping screw of claim 1, where the top of each cutting edge is a straight line, The straight line is inclined and not parallel to the axial center line, so that the straight line has a second included angle when projecting on the axial center line. Such as the self-tapping screw of claim 7, wherein the second included angle is between 5 and 35 degrees. For example, the self-tapping screw of claim 7, wherein each of the cutting edges has a cutting arc and an inclined surface on both sides of the top, and the radial section of the rod has an arc, and the arc passing through the top The normal line of is formed a reference line, the cutting arc has a first angle between the reference line, and there is a second angle between the inclined surface and the reference line, and the second angle is greater than the first angle. Such as the self-tapping screw of claim 9, wherein the first angle is between 15 and 20 degrees. Such as the self-tapping screw of claim 9, wherein the second angle is between 30 and 37 degrees.

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