A low torque square thread self-tapping screw

Abstract

The utility model relates to the technical field of fasteners, and specifically to a low-torque square-tooth self-tapping screw, which at least includes a screw rod and a screw head, wherein the screw rod includes a square-tooth section provided with a square thread, and the axial projection of any circle of the square thread is a regular polygon, and the angle of the regular polygon is a cutting angle. Since the square thread has a cutting angle, it can form a sawtooth shape to cut wood fibers, making it easier and more convenient to tap into wooden products; compared with directly setting a protrusion on a round thread, the square thread is simple to process, and can still be processed using a tooth plate, without the need to modify the process, and the structure is more solid.

Description

Technical Field

[0001] The utility model relates to the technical field of fasteners, in particular to a low-torque square-tooth self-tapping screw. Background Art

[0002] Conventional self-tapping screws, especially self-tapping screws suitable for low torque for wood products, have round threads, which are formed by extrusion on the medium. Since the cross-sectional size of the round threads is consistent when they are tapped into the medium, it is impossible to form a good cutting effect on the medium, such as the wood fiber of wood. In order to improve the cutting effect, in the prior art, for example, "a self-tapping screw with sawtooth threads" disclosed in Chinese patent documents, with announcement number CN204512124U, the end of the screw is a transition thread zone, which reduces the outer diameter and extends to a truncated cone or cone. At least 2-5 turns of threads or all threads on the screw shaft or the transition thread zone are sawtooth threads. Although the cutting ability of the screw is improved, it needs to be provided with sawtooth threads, and the processing of sawtooth threads is very difficult, making the cost of this screw too high in actual production. Utility Model Content

[0003] The utility model aims to solve the problem of poor cutting effect of existing self-tapping screws and provide a self-tapping screw which can enhance the cutting effect and is easy to process.

[0004] The technical solution provided by the utility model is as follows:

[0005] A low-torque square-thread self-tapping screw comprises at least a screw rod and a screw head, wherein the screw rod comprises a square-thread section provided with a square thread, and the axial projection of any circle of the square thread is a regular polygon, and the angle of the regular polygon is a cutting angle.

[0006] Due to the inconsistency of the regular polygonal square thread in the circumferential direction of the cross-section, that is, the square thread has a protruding cutting angle, it can form a sawtooth shape to cut the wood fibers when rotating, making it easier and more convenient to penetrate into wooden products, and can penetrate wood and other objects to be fixed under lower torque; compared with directly setting protrusions on round threads, square threads are simple to process, can still be processed with tooth plates, do not need to modify the process, and have a more solid structure.

[0007] Preferably, the axial projection of any circle of the square thread is a square. The cross-sectional shape of the square is more similar to a circle, has fewer sides, and is less difficult to process.

[0008] Preferably, a deflection angle β is provided between two adjacent circles of the square thread, the deflection angle β is in the range of 8°±5°, and the direction of the deflection angle β is opposite to the screwing direction of the self-tapping screw. That is, viewed from the axial direction, the square thread presents a square spiral shape, which avoids stress concentration during cutting, evenly distributes cutting resistance, and improves the structural strength and cutting force of the screw.

[0009] Preferably, the axial projection shape of the cutting angle is a rounded corner, which improves the structural strength of the cutting angle and reduces the difficulty of processing.

[0010] Preferably, the tooth angle α of the square thread of the square tooth segment is in the range of 40°±5°, and the tooth angle is relatively thin, which further reduces its resistance while meeting its basic performance, and also increases its grip in the medium.

[0011] Preferably, it further comprises a tip, wherein a transition thread is arranged on the outer periphery of the tip.

[0012] Preferably, the tip of the screw is sawtooth-shaped.

[0013] Preferably, the tip of the screw is in a cut-tail shape, which cooperates with a square thread to increase the cutting force and reduce damage to the medium.

[0014] Preferably, the angle between the upper surface of the tooth profile of the square tooth segment and the horizontal plane is an upper tooth angle γ, and the range of the upper tooth angle γ is 10°±2°.

[0015] Compared with the prior art, the utility model has the following beneficial effects:

[0016] Due to the cutting angle of the square thread, it can form a sawtooth shape to cut the wood fibers, making it easier and more convenient to penetrate into wooden products. Compared with directly setting protrusions on round threads, square threads are simple to process and can still be processed with tooth plates without modifying the process, and the structure is more solid. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a side view schematic diagram of the first embodiment of the utility model;

[0018] Figure 2 for Figure 1 A simplified enlarged schematic diagram of the middle A;

[0019] Figure 3 for Figure 1 Schematic diagram of the cross section at BB;

[0020] Figure 4 It is a top view schematic diagram of the first embodiment of the utility model;

[0021] Figure 5It is a side view schematic diagram of the second embodiment of the utility model;

[0022] Figure 6 It is a top view schematic diagram of the second embodiment of the utility model;

[0023] Figure 7 It is a side view schematic diagram of the third embodiment of the utility model.

[0024] Explanation of the reference numerals: screw 1 , square tooth segment 11 , square tip 111 , square edge 112 , tooth profile angle α, deflection angle β, upper tooth angle γ, toothless segment 12 , screw head 2 , square groove 21 , cross groove 22 , tip 3 . DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0026] Embodiment 1, as shown in the figure, a low-torque square-thread self-tapping screw comprises a screw 1, a screw head 2 and a tip 3, the screw 1 comprises a square-thread segment 11 provided with a square thread, the axial projection of any circle of the square thread is a regular polygon, this embodiment uses a square as an example for illustration, the corner of the square is a cutting angle 111, this embodiment is also provided with a toothless segment 12 without a thread, the toothless segment 12 is set in length according to needs or is not provided with a toothless segment 12, the tip of the screw 1 is a cut-tail shape, the screw head 2 is a countersunk head and is provided with a square groove 21, as shown in FIG. Figure 4 shown.

[0027] The axial projection of the square thread of the square tooth segment 11 is a square, the four corners of the square are cutting corners 111, the four sides of the square are square edges 112, and the shape of the cutting corner 111 is rounded, as shown in FIG. Figure 3 As shown, the cross-sectional shape of the square is closer to a circle, has fewer sides, and is less difficult to process.

[0028] A deflection angle β is set between two adjacent circles of the square thread, and the range of the deflection angle β is 8°±5°. The deflection angle β in this embodiment is preferably 8°, but is not limited to 8°. The direction of the deflection angle β is opposite to the screw-in direction of the self-tapping screw, that is, from the axial direction, the square thread presents a square spiral shape, avoiding stress concentration during cutting, evenly distributing the cutting resistance, and improving the structural strength and cutting force of the screw.

[0029] The tooth profile angle α of the square thread of the square tooth segment 11 is in the range of 40°±5°, and is preferably 40° in this embodiment, but is not limited to 40°. Figure 2As shown in the figure, the tooth angle is relatively thin, which further reduces its resistance while meeting its basic performance, and also increases its grip in the medium. Figure 2 As shown, the angle between the upper surface of the tooth profile of the square tooth segment and the horizontal plane is the upper tooth angle γ, and the range of the upper tooth angle γ is 10°±2°. In this embodiment, it is preferably 10°, but it is not limited to 10°.

[0030] Due to the inconsistency of the square thread in the circumferential direction of the cross section, that is, the square thread has a cutting angle 111, it can form a sawtooth shape to cut the wood fibers when rotating, making it easier and more convenient to penetrate into wooden products; compared with directly setting a protrusion on the round thread, the square thread is simple to process, and can still be processed with a tooth plate without modifying the process, and the structure is more solid.

[0031] Embodiment 2, as Figure 5 and Figure 6 As shown, the tip 3 of the screw 1 is in a cut-tail shape, the screw head 2 is a trumpet head, and is provided with a cross groove 22. Other settings are the same as those in the first embodiment. The cut-tail-shaped tip is matched with a square thread to increase the cutting force and reduce damage to the medium.

[0032] Embodiment three, as Figure 7 As shown, the tip of the screw rod 1 is sawtooth-shaped, and other configurations are the same as those in the first embodiment.

[0033] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A low-torque square-thread self-tapping screw, comprising at least a screw rod (1) and a screw head (2), characterized in that: The screw rod (1) comprises a square thread segment (11) provided with a square thread, wherein the axial projection of any circle of the square thread is a regular polygon, and the angle of the regular polygon is a cutting angle (111).

2. The low torque square thread self-tapping screw according to claim 1, characterized in that: The axial projection of any circle of the square thread is a square.

3. The low torque square thread self-tapping screw according to claim 2, characterized in that: A deflection angle β is arranged between two adjacent circles of the square thread, the deflection angle β has a magnitude range of 8°±5°, and the direction of the deflection angle β is opposite to the screwing direction of the self-tapping screw.

4. The low torque square thread self-tapping screw according to claim 1, 2 or 3, characterized in that: The axial projection shape of the cutting corner (111) is a rounded corner.

5. The low torque square thread self-tapping screw according to claim 1, 2 or 3, characterized in that: The square thread angle α of the square thread segment (11) is in the range of 40°±5°.

6. The low torque square thread self-tapping screw according to claim 1, 2 or 3, characterized in that: It also comprises a tip portion (3), the outer periphery of which is provided with a transition thread.

7. The low torque square thread self-tapping screw according to claim 1, 2 or 3, characterized in that: The tip (3) of the screw (1) is sawtooth-shaped.

8. The low torque square thread self-tapping screw according to claim 1, 2 or 3, characterized in that: The tip (3) of the screw (1) is in a cut-tail shape.

9. The low torque square thread self-tapping screw according to claim 1, 2 or 3, characterized in that: The angle between the upper surface of the tooth profile of the square tooth segment (11) and the horizontal plane is the upper tooth angle γ, and the range of the upper tooth angle γ is 10°±2°.

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