A double counterbore type self-tapping screw

Abstract

The utility model relates to a screw, specifically disclose a double counterbore type self -tapping screw. The double counterbore type self -tapping screw includes the main part, one end of the main part is head, the other end is drill tip part, the head of main part is equipped with operation counterbore, the main part on be equipped with screw thread, the screw thread extend to drill tip part, the bottom of operation counterbore is equipped with auxiliary counterbore, the inner wall of auxiliary counterbore is equipped with a plurality of along the circumferential distribution's pressure nub, the screw thread includes main subsection and tail tooth subsection along extension direction, the tail tooth subsection extend to drill tip part, the tail tooth subsection extend 0.5~1 circle, the height of tail tooth subsection gradually increases from drill tip part to main subsection. The double counterbore type self -tapping screw described above can cooperate with screwdriver well, and the drilling connection operation is convenient, and the strength of screw thread is more stable, and the drilling efficiency is high.

Description

Technical Field

[0001] This utility model relates to a screw, specifically a double countersunk self-tapping screw. Background Technology

[0002] Screws are common threaded fasteners, typically using self-tapping holes or self-threaded designs, and are widely suitable for materials with relatively low hardness, such as wood and plastic. A typical screw consists of a body, a head at one end, and a drill tip at the other. The body has threads that extend to the drill tip, and the head has a countersunk hole for engaging with a screwdriver. Chinese utility model patent CN 217713265 U discloses a toothed double-threaded screw, illustrating a common screw structure with advantages such as easy drilling and convenient use.

[0003] In practice, the most common problem with screws is that they are difficult to hold. Before or in the early stages of drilling, the screw and screwdriver are prone to wobbling, requiring the operator to assist in positioning, which makes the drilling and connection operation inconvenient. Summary of the Invention

[0004] The technical problem to be solved by this utility model is to provide a double countersunk self-tapping screw that can be well matched with a screwdriver, making drilling and connection operations convenient, while the thread strength is more stable and the drilling efficiency is high.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a double countersunk self-tapping screw, comprising a body, one end of which is a head and the other end is a drill tip. The head of the body is provided with an operating countersunk hole, and the body is provided with threads that extend to the drill tip. The bottom of the operating countersunk hole is provided with an auxiliary countersunk hole, and the inner wall of the auxiliary countersunk hole is provided with a number of pressing protrusions distributed circumferentially. The threaded section includes a main section and a tail section along the extension direction. The tail section extends to the drill tip and extends 0.5 to 1 turn. The height of the tail section gradually increases from the drill tip to the main section.

[0006] During drilling, the screwdriver is inserted into the countersunk hole, and its tip can be inserted into the auxiliary countersunk hole. The clamping lug and screwdriver engage, creating a clamping force between the screw and the bolt, reducing wobble and improving drilling convenience. Furthermore, compared to existing screws, the tailstock segment of this application is shorter, the threads are fuller and stronger, resulting in higher reliability during drilling, a significantly reduced probability of thread breakage, and higher drilling efficiency. Simultaneously, the threads provide better coverage of the drill tip, increasing the connection tensile strength and further enhancing connection reliability.

[0007] Preferably, the maximum distance between the inner wall of the auxiliary countersunk hole and the center line of the main body is denoted as A, and the maximum distance between the inner wall of the operating countersunk hole and the center line of the main body is denoted as B. Then A = 1 / 3 to 2 / 3B, and the auxiliary countersunk hole can better cooperate with the screwdriver.

[0008] Preferably, the cross-section of the auxiliary countersunk hole is circular, and the cross-section of the operating countersunk hole is quincunx-shaped or regular hexagonal.

[0009] Preferably, the cross-sectional shape of the auxiliary countersunk hole is the same as that of the operating countersunk hole.

[0010] Preferably, the height of the clamping protrusion gradually decreases from the bottom of the auxiliary countersunk hole to the opening, and the change in the height of the clamping protrusion is adapted to the size change trend of the screwdriver tip, so as to better cooperate with the screwdriver for clamping.

[0011] Preferably, the head is a countersunk type, and anti-loosening ribs are distributed on the sides of the head.

[0012] Preferably, the main body comprises a first segment and a second segment along the axial direction from the drill tip. The threads on the first segment are double-threaded threads, with one thread being the main thread and the other thread being the auxiliary thread. The main thread extends to the second segment, and the thread height of the auxiliary thread is lower than that of the main thread.

[0013] The main thread and the auxiliary thread drill together and provide locking force together, which improves the stability and reliability of the connection.

[0014] Preferably, the main thread has several notches distributed on it, and each notch is arranged in a spiral pattern around the center line of the main body, with the spiral direction opposite to that of the thread.

[0015] The notch can act as a sawtooth cutting effect during drilling, improving drilling efficiency.

[0016] Preferably, the notch is divided into several groups, and each group of notches is arranged in a spiral pattern around the center line of the main body, with the spiral angle of each group of notches being equal.

[0017] The phase angles of the notches are different during drilling, and the coordinated cutting effect of each group is better. Attached Figure Description

[0018] Figure 1 This is a front view of the double countersunk self-tapping screw in this embodiment; Figure 2 This is a partial structural diagram of the first segment in the double countersunk self-tapping screw of this embodiment; Figure 3 This is a schematic diagram of the double countersunk self-tapping screw in this embodiment; Figure 4 This is a front view of the head of the double countersunk self-tapping screw in this embodiment; Figure 5 This is a structural schematic diagram of the double countersunk self-tapping screw from another perspective in this embodiment; Figure 6 for Figure 5 A magnified view of a section at point C. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model. Example

[0020] like Figure 1 As shown, a double countersunk self-tapping screw includes a body 1, one end of which is a head 2, and the other end is a drill tip 3. In one specific embodiment, the head 2 is countersunk, and anti-loosening ribs 21 are distributed on the side of the head 2. Figure 3 and Figure 4 As shown, the head 2 of the main body 1 is provided with an operating countersunk hole 51, such as... Figure 1 As shown, the main body 1 is provided with threads, which extend to the drill tip 3.

[0021] like Figure 4 and Figure 5 As shown, the threaded section includes a main segment 411 and a tail segment 412 along the extension direction. The tail segment 412 extends to the drill tip 3 and extends 0.5 to 1 turn. The height of the tail segment 412 gradually increases from the drill tip 3 to the main segment 411.

[0022] Compared with existing screws, the tail section 412 of this application is shorter, the threads are fuller and stronger, the reliability during drilling is higher, the probability of thread breakage is greatly reduced, the drilling efficiency is higher, and the thread covers the drill tip 3 better, resulting in greater connection tensile force, which can improve the connection reliability to a certain extent.

[0023] like Figure 1 and Figure 2As shown, the main body 1 comprises a first segment 12 and a second segment 11 sequentially along the axial direction from the drill tip. The length of the first segment 12 is 0.4 to 0.5 times the length of the second segment 11. The threads on the first segment 12 are double-threaded threads, with one thread being the main thread 41 and the other thread being the auxiliary thread 42. The main thread 41 extends to the second segment 11, and the height of the auxiliary thread 42 is lower than that of the main thread 41, with the height of the auxiliary thread 42 being 0.4 to 0.5 times that of the main thread 41. The main thread 41 and the auxiliary thread 42 drill together and jointly provide locking force, improving the stability and reliability of the connection.

[0024] like Figure 1 and Figure 2 As shown, the main thread 41 has several notches 43 distributed on it. Each notch 43 is arranged in a spiral pattern around the center line of the main body 1, and the spiral direction is opposite to the spiral direction of the thread. The notches 43 are divided into several groups, and each group of notches 43 is arranged in a spiral pattern around the center line of the main body 1, and the spiral angle of each group of notches 43 is equal.

[0025] Notch 43 acts as a sawtooth cutting mechanism during drilling, improving drilling efficiency. Different sets of notches 43 cut at different phase angles during drilling, resulting in better coordinated cutting performance.

[0026] like Figure 3 and Figure 4 As shown, the bottom of the countersunk hole 51 is provided with an auxiliary countersunk hole 52, and the inner wall of the auxiliary countersunk hole 52 is provided with a plurality of clamping protrusions 53 distributed circumferentially. The maximum distance from the inner wall of the auxiliary countersunk hole 52 to the center line of the main body 1 is denoted as A, and the maximum distance from the inner wall of the operating countersunk hole 51 to the center line of the main body 1 is denoted as B. Then A = 1 / 3 to 2 / 3B, and the auxiliary countersunk hole 52 can better cooperate with the screwdriver.

[0027] As a specific implementation method, such as Figure 3 and Figure 4 As shown, the cross-section of the auxiliary countersunk hole 52 is circular, and the cross-section of the operating countersunk hole 51 is plum blossom-shaped or regular hexagonal.

[0028] In another specific implementation, the cross-sectional shape of the auxiliary countersunk hole 52 is the same as that of the operating countersunk hole 51.

[0029] Specifically, such as Figure 3 and Figure 4 As shown, the height of the clamping protrusion 53 gradually decreases from the bottom of the auxiliary countersunk hole 52 to the opening. The change in the height of the clamping protrusion 53 is adapted to the size change trend of the screwdriver tip, which can better cooperate with the screwdriver for clamping.

[0030] During drilling, the screwdriver is inserted into the countersunk hole 51, and the tip of the screwdriver can be inserted into the auxiliary countersunk hole 52. The clamping protrusion 53 and the screwdriver are clamped together, which can form a certain clamping force between the screw and the screwdriver, reduce the shaking between the screwdriver and the screw, and improve the convenience of drilling operation.

[0031] In summary, the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A double countersunk self-tapping screw, comprising a body, one end of which is a head and the other end of which is a drill tip, the head of which is provided with an operating countersunk hole, and the body is provided with threads extending to the drill tip; Its features are: The bottom of the operating countersunk hole is provided with an auxiliary countersunk hole, and the inner wall of the auxiliary countersunk hole is provided with a number of pressing protrusions distributed circumferentially. The threaded section includes a main section and a tail section along the extension direction. The tail section extends to the drill tip and extends 0.5 to 1 turn. The height of the tail section gradually increases from the drill tip to the main section.

2. The double countersunk self-tapping screw according to claim 1, characterized in that: Let A be the maximum distance between the inner wall of the auxiliary countersink and the center line of the main body, and let B be the maximum distance between the inner wall of the operating countersink and the center line of the main body. Then A = 1 / 3 to 2 / 3B.

3. The double countersunk self-tapping screw according to claim 1, characterized in that: The auxiliary countersunk hole has a circular cross-section, and the operating countersunk hole has a quincunx or regular hexagonal cross-section.

4. The double countersunk self-tapping screw according to claim 1, characterized in that: The cross-sectional shape of the auxiliary countersunk hole is the same as that of the operating countersunk hole.

5. The double countersunk self-tapping screw according to claim 1, characterized in that: The height of the clamping protrusion gradually decreases from the bottom of the auxiliary countersunk hole to the opening.

6. The double countersunk self-tapping screw according to claim 1, characterized in that: The head is a countersunk type, and anti-loosening ribs are distributed on the sides of the head.

7. The double countersunk self-tapping screw according to any one of claims 1-6, characterized in that: The main body comprises a first segment and a second segment along the axial direction from the drill tip. The threads on the first segment are double-threaded threads, with one thread being the main thread and the other thread being the auxiliary thread. The main thread extends to the second segment, and the thread height of the auxiliary thread is lower than that of the main thread.

8. The double countersunk self-tapping screw according to claim 7, characterized in that: The main thread has several notches distributed on it. Each notch is arranged in a spiral pattern around the center line of the main body, and the spiral direction is opposite to the spiral direction of the thread.

9. The double countersunk self-tapping screw according to claim 8, characterized in that: The notches are divided into several groups, and each group of notches is arranged in a spiral pattern around the center line of the main body, with the spiral angle of each group of notches being equal.

Images