Novel drilling-free self-drilling screw for cement

Abstract

The utility model discloses a novel drilling-free self-drilling screw for cement, which is characterized in that a hole only needs to be pre-drilled, and in the drilling process, a wedge-shaped cone can quickly guide a large amount of cement dust in the hole into a chip groove and destroy concrete hard lumps in the hole, so that the drilling speed of the cement screw is accelerated, and the drilling efficiency of the screw is improved. The subsequent high-low double threads can better cut the cement wall hole; meanwhile, the high-low double-thread design solves the problem that when the threads are drilled into a hole, the threads are prone to being affected by the unevenness in the hole, and the screw deviates, the high-low double threads have a certain guiding effect, and large-particle concrete hard blocks and fine-crushed cement dust can be discharged through a gap between the high-low double threads; the influence on the tapping efficiency caused by blockage of large concrete particles is reduced; moreover, after the locked object and the cement wall are locked by the cement screw, large-particle concrete chippings and fine dust which are not discharged can be uniformly distributed between the high-low double threads and the wedge-shaped cone, so that the large-particle concrete chippings and the fine dust are in interference fit with the cement screw and the cement wall brick.

Description

Technical Field

[0001] This utility model belongs to the field of fastener technology, specifically relating to a novel self-drilling screw for cement that requires no drilling. Background Technology

[0002] Screws are tools that use the friction generated between the rotating threads on a screw and an object to gradually tighten it. As an indispensable industrial necessity in daily life, screws are widely used in construction. Compared to expansion bolts, they offer significantly improved tightening power over concrete blocks.

[0003] In existing technology, to ensure that cement screws can be drilled into cement or concrete, a hole must first be drilled in the surface of the cement brick using an electric drill, and then the screw is driven into the cement brick. Cement screws are generally designed based on self-drilling screws, with an increased shank diameter and two to three triangular cutting edges on the shank. This allows the screw to be tightly locked to the cement, and the triangular notches ensure that cement debris is discharged in time, preventing the screw from failing to drill smoothly into the cement. However, this structure still has shortcomings. The main reason is that drilling cannot guarantee a smooth inner surface of the hole, and a large amount of hard concrete will remain inside the hole, causing significant frictional resistance when the cement screw contacts the cement wall brick, which is time-consuming and laborious. At this point, it is necessary to use an electric drill to clean and smooth the hole two to three times to ensure that the cement screw can be successfully drilled into the cement wall brick, which greatly increases the cost. Utility Model Content

[0004] Purpose of the utility model: In order to overcome the shortcomings of the existing technology, this utility model provides a novel self-drilling screw for cement that does not require drilling.

[0005] In order to solve the technical problems existing in the prior art, the cement screw of this utility model redesigns the threads and tail end, uses two sets of high and low threads to spiral on the rod, and designs a wedge-shaped cone at the tail end to ensure that the cement screw can smoothly enter the cement wall brick.

[0006] Technical solution: A novel self-drilling screw for cement, comprising a screw head, a screw rod, high and low double threads, a chip removal groove, a chip guide groove, a tail tip, a wedge-shaped cone, a serrated cutting edge, and a screwing groove;

[0007] The screw head and screw rod are integrally formed. The screw head is countersunk and has a 0.5mm thick reinforcing rib on its surface. The screw head is provided with a screwing groove.

[0008] The screw is provided with high and low double threads and chip removal grooves. The 90° sawtooth cutting edge on the high and low double threads extends to the screw and is distributed in a spiral shape to the tail tip.

[0009] The tail tip is provided with a chip guide groove, and a plurality of wedge-shaped cones are arranged in the chip guide groove, the wedge-shaped cone is 0.5mm high, the two sides extend to the surface of the screw by the inclined surface with a 45° draft angle, and the upper side extends to the surface of the screw by the inclined surface with a 15° draft angle; the large-particle chippings cut by the wedge-shaped cone and the fine dust cut by the high-low double thread are evenly distributed between the chip guide groove, the chip removal groove and the gap of the high-low double thread;

[0010] The screw head drives the high-low double thread on the screw rod and the screw rod body to drill into the cement wall, the tail tip of the cement screw first enters the hole, the rough surface in the hole is polished and cleaned by the wedge-shaped cone at the tail end, the concrete hard block in the hole is removed, and the broken concrete chippings and a large amount of powder chippings can be transferred to the chip guide groove and discharged along the chip removal groove formed by the gap of the high-low double thread.

[0011] As optimization, the outer diameter of the high thread on the high-low double thread is φ7.3-7.6mm, the screw spacing is 5.6mm, and the thread angle is 47°-53°.

[0012] As optimization, the outer diameter of the low thread on the high-low double thread is 6.5-6.9mm, the screw spacing is 5.6mm, and the thread angle is 57°-63°.

[0013] Beneficial effects: the screw only needs to be pre-drilled into a hole, in the drilling process, the wedge-shaped cone can quickly guide a large amount of cement dust in the hole into the chip removal groove, and the concrete hard block in the hole is broken, so that the drilling speed of the cement screw is accelerated, and the subsequent high-low double thread can better cut the hole in the cement wall; meanwhile, the high-low double thread design solves the problem that the thread is easily deviated when drilling into the hole due to the high-low unevenness in the hole, the high-low double thread has a certain guiding effect, the gap between the high-low double threads can discharge the large-particle concrete hard block and the fine cement dust, and the efficiency of hole drilling is reduced due to the blockage of the large-particle concrete particles; and when the cement screw locks the locked object and the cement wall, the large-particle concrete chippings and the fine dust that are not discharged can be evenly distributed between the high-low double thread and the wedge-shaped cone, so as to form an interference fit with the cement screw and the cement wall brick, improve the pull-out resistance, make the bearing capacity stronger, be more impact-resistant, and not easy to fall off. BRIEF DESCRIPTION OF DRAWINGS

[0014] Fig. 1 It is a schematic diagram of the overall structure of the utility model;

[0015] Fig. 2 It is a schematic diagram of the cross-sectional structure of the utility model;

[0016] Fig. 3 It is a schematic diagram of the local structure of the utility model. DETAILED DESCRIPTION

[0017] Design of wedge taper and high-low double thread of screw tail

[0018] As Figs. 1-3 shown, a new type of self-drilling screw for cement, including screw head 1, screw rod 2, high-low double thread 3, chip groove 4, chip guide groove 5, tail tip 6, wedge taper 7, saw blade 8 and screwing groove 9.

[0019] The screw head 1 and the screw rod 2 are integrally formed, the screw head 1 is designed as a countersunk head, and a reinforcing rib with a thickness of 0.5 mm is attached to the surface, the countersunk head design can facilitate the sinking of the cement screw into the surface of the locked object, and the reinforcing rib can be in close contact with the locked object when the screw head is sunk into the inside of the locked object, thereby increasing the friction between the screw head and the locked object and preventing the screw from being easily rotated out of the locked object. The screw head 1 is provided with a screwing groove 9.

[0020] The screw rod 2 is provided with high-low double thread 3 and chip groove 4, the high thread outer diameter of the high-low double thread 3 is φ7.3-7.6 mm, the screw pitch is 5.6 mm, and the thread angle is 47°-53°. The low thread outer diameter of the high-low double thread 3 is 6.5-6.9 mm, the screw pitch is 5.6 mm, and the thread angle is 57°-63°, wherein the 90° saw blade 8 on the thread extends to the screw rod 2 and is distributed in a spiral line to the tail tip 6, the saw blade 8 on the high thread plays a role in cutting cement wall bricks, and the saw blade 8 on the low thread also plays a role in guiding a small amount of cement debris.

[0021] The tail tip 6 is provided with a chip guide groove 5, the chip guide groove 5 is arranged with a plurality of wedge tapers 7, the wedge tapers 7 are 0.5 mm high, the two sides extend to the surface of the screw rod 2 by 45° draft angle, and the upper side extends to the surface of the screw rod 2 by 15° draft angle; when the cement screw tightly locks the locked object and the cement wall, the large particle debris cut by the wedge tapers 7 and the fine dust cut by the high-low double thread 3 are evenly distributed between the chip guide groove 5, the chip groove 4 and the gap of the high-low double thread 3, so that the cement screw and the cement wall are in interference fit, when the cement screw is subjected to a pulling force perpendicular to the surface of the screw head, the high-low double thread 3 structure formed by the high thread with an angle of 47°-53° and the low thread with an angle of 57°-63° and the upper side 15° wedge taper 7 can provide a considerable resistance, the interference fit between the cement screw, the cement wall and the debris dust can provide a torque force to prevent falling off, and the carrying capacity is larger and the impact resistance is stronger.

[0022] In this embodiment, first, the electric drill is used to drill a hole in the cement wall brick, and then the cement screw is screwed into the cement wall. First, the screw head 1 drives the screw rod 2 and the high-low double thread 3 on the screw rod 2 to drill into the cement wall. The tail tip 3 of the cement screw first enters the hole. The wedge-shaped cone 7 at the tail end cleans and polishes the rough surface in the hole, removing the concrete hard blocks in the hole. These concrete hard blocks can greatly increase the frictional resistance between the thread and the cement wall during the hole drilling process. The broken concrete debris and a large amount of powder debris generated can be transferred to the chip removal groove 5 and discharged through the chip removal groove 4 formed by the gap between the high-low double thread 3. At the same time, the smooth hole surface also facilitates the thread cutting of the cement wall brick, further improving the speed of screwing in. The high-low double thread 3 can improve the fit with the cement wall brick. Since the hole drilled by the electric drill is not smooth, the high-low double thread 3 can tightly lock the uneven hole and discharge the powder generated during the cutting process through the chip removal groove 4. The un-discharged debris particles can also form a dense powder layer between the high-low double thread 3, improving the locking effect between the cement screw and the cement wall brick.

[0023] The conventional cement screw needs to use an electric drill to drill a pre-drilled hole and remove the cement debris and dust in the hole through 2-3 times of drilling, which is time-consuming and labor-intensive. The screw of the utility model only needs to pre-drill a hole. During the drilling process, the wedge-shaped cone can quickly guide a large amount of cement dust in the hole into the chip removal groove and break the concrete hard blocks in the hole, accelerating the speed of the cement screw drilling, and making the subsequent high-low double thread better cut the cement wall hole. At the same time, the high-low double thread design of the utility model solves the problem that the thread is easily deviated when drilling into the hole due to the high-low unevenness in the hole. The high-low double thread has a certain guiding effect. The gap between the high-low double threads can discharge large-particle concrete hard blocks and fine cement dust, reducing the impact on the drilling efficiency caused by the blockage of large-particle concrete particles. When the cement screw locks the locked object and the cement wall tightly, the un-discharged large-particle concrete debris and fine dust can be evenly distributed between the high-low double thread and the wedge-shaped cone, thereby forming an interference fit with the cement screw and the cement wall brick, improving the pull-out resistance, making the load-carrying capacity stronger, more resistant to impact, and not easy to fall off.

[0024] The above description clearly and completely describes the technical solutions in the embodiments of the utility model, so that those skilled in the art can better understand the advantages and features of the utility model, and thus define the protection scope of the utility model more clearly. The embodiments described in the utility model are only a part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

Claims

1. A new type of self-drilling screw for cement, characterized by: It comprises a screw head (1), a screw rod (2), high-low double thread (3), chip flute (4), chip flute (5), tail tip (6), wedge-shaped cone (7), sawtooth edge (8) and twist groove (9). The screw head (1) and the screw rod (2) are integrally formed, the screw head (1) is designed as a countersunk head, and a reinforcing rib with a thickness of 0.5 mm is attached to the surface, and the screw head (1) is provided with a twist groove (9). The screw rod (2) is provided with high-low double thread (3) and chip flute (4), the 90° sawtooth edge (8) on the high-low double thread (3) extends to the screw rod (2) and is distributed in a spiral line to the tail tip (6). The tail tip (6) is provided with a chip flute (5), and a plurality of wedge-shaped cones (7) are arranged in the chip flute (5), the wedge-shaped cone (7) is 0.5 mm high, the two sides extend to the surface of the screw rod (2) by 45° draft angle, and the upper side extends to the surface of the screw rod (2) by 15° draft angle; the large particle chips cut by the wedge-shaped cone (7) and the fine dust cut by the high-low double thread (3) are evenly distributed between the chip flute (5), the chip flute (4) and the high-low double thread (3). The screw head (1) drives the screw rod (2) and the high-low double thread (3) on the screw rod (2) to drill into the cement wall, the tail tip (6) of the cement screw enters the hole first, the wedge-shaped cone (7) at the tail end cleans and polishes the rough surface in the hole, removes the concrete hard block in the hole, and can transfer the broken concrete chips and a large amount of powder chips to the chip flute (5), and the chip flute (4) formed by the gap of the high-low double thread (3) is discharged.

2. The new type of self-drilling screw for cement without drilling according to claim 1, characterized in that: The high thread outer diameter of the high-low double thread (3) is φ7.3-7.6 mm, the screw pitch is 5.6 mm, and the thread angle is 47°-53°.

3. The new type of self-drilling screw for cement without drilling according to claim 1, characterized in that: The low thread outer diameter of the high-low double thread (3) is 6.5-6.9 mm, the screw pitch is 5.6 mm, and the thread angle is 57°-63°.

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