Expansion bolt
By designing deformation grooves and limiting ring grooves on the expansion tube, the stability problem of expansion bolts during labor-saving installation is solved, achieving a more stable fixing effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-09
- Publication Date
- 2026-03-03
AI Technical Summary
When installing existing expansion bolts in a labor-saving manner, the gap between the bolt head and the nut is relatively large, resulting in insufficient installation stability and affecting the fixing effect.
Multiple circumferentially spaced deformation grooves are made on the expansion tube, and a limiting ring groove is set at the screw head. By screwing in the nut, the screw head is driven to squeeze the expansion tube, causing it to expand outward in the deformation groove area, thereby enhancing the friction and fixation with the hole wall.
This improves the installation stability and fixing effect of expansion bolts, ensuring that the expansion tube is in close contact with the hole wall, making the rod more stable.
Smart Images
Figure CN223964735U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of fasteners, and in particular to expansion bolts. Background Technology
[0002] Fasteners, also known as standard parts in the market, are a general term for mechanical parts used to fasten two or more parts (or components) together into a whole. Expansion screws are a common type of fastener. Expansion screws, generally referring to metal expansion screws, consist of a screw and an expansion tube. The fixing effect of expansion screws is achieved by using a wedge-shaped slope to cause expansion and generate frictional gripping force.
[0003] Common expansion bolts consist of a screw, a nut, and an expansion tube. The screw and nut are threaded together, and the expansion tube is fitted onto the screw, sandwiched between the screw head and the nut. The screw head is frustoconical, with a smaller diameter (smaller than the inner diameter of the expansion tube) facing the expansion tube, and a larger diameter (larger than the inner diameter of the expansion tube). In use, one end of the screw head enters the hole for the expansion bolt until the expansion tube is also inserted. When the nut is tightened, the screw moves outward, causing the screw head to move axially, which in turn compresses the expansion tube, creating significant positive pressure on its outer circumference. This frictional self-locking between the wall, the expansion tube, and the screw head achieves a secure fixation. Expansion bolts can be installed using either a less strenuous insertion method or a more secure driving method.
[0004] When using the above-mentioned expansion bolts, the screw head and expansion tube need to be inserted into the mounting hole. If a larger diameter mounting hole is used, the installation can be done by inserting the bolt head into the hole to save effort. Although the screw head makes full contact with the hole wall to ensure stability, the large gap between the screw head and the nut means that the external part of the expansion bolt may sometimes have room for circumferential movement, which affects the installation stability. Utility Model Content
[0005] To ensure the stability of the expansion bolt during use while saving effort during installation, this application provides an expansion bolt.
[0006] The expansion bolts provided in this application adopt the following technical solution:
[0007] An expansion bolt includes a screw, a nut, and an expansion tube. The screw includes a screw head and a shaft. The end of the shaft away from the screw head is threaded into the nut. The expansion tube is fitted onto the shaft and is held between the screw head and the nut. The screw head abuts against the expansion tube. The expansion tube has multiple deformation grooves along its axial direction, and these grooves are spaced at equal angles around the circumference of the expansion tube.
[0008] By adopting the above technical solution, the expansion tube can be deformed and protrude outwards by opening a deformation groove. In use, the screw head and expansion tube are placed into the corresponding hole, and the nut is screwed into the rod body, causing the screw head to move in the direction of the nut. The screw head squeezes the expansion tube. Due to the hard compression of the expansion tube by the screw head, the deformation of the expansion tube is mainly in the middle section of the deformation groove rather than at the end of the expansion tube. Finally, the middle section of the deformation groove of the expansion tube expands outwards and deforms, squeezing the hole wall and restricting the expansion bolt to be fixed in the hole. Since the outward expansion area of the expansion tube is located in the middle area of the hole for the expansion tube installation, the expansion bolt is more stable after installation, the abutment between the expansion tube and the hole wall is more solid, and the rod body is more stable.
[0009] Optionally, the deformation groove is formed at one end of the expansion tube near the screw head.
[0010] By adopting the above technical solution, the deformation groove is opened at the end of the expansion tube near the screw head, so that the deformation area of the expansion tube is separated from the nut by a certain distance, the overall expansion bolt is not easy to come out, and the expansion tube is easier to deform under pressure.
[0011] Optionally, the end of the deformation groove is spaced apart from the end of the expansion tube.
[0012] By adopting the above technical solution, the deformation groove will not penetrate along the axial direction of the expansion tube, making it less likely for the expansion tube to undergo outward expansion deformation at the end when compressed.
[0013] Optionally, the width of the deformation groove gradually decreases from the middle region to both ends.
[0014] By adopting the above technical solution, the expansion tube is further guaranteed to expand outward in the middle area of the deformation groove, and the position of contact between the expansion tube and the hole wall of the corresponding mounting hole is more accurately limited.
[0015] Optionally, the expansion tube has a deformation notch at its end, and there are multiple deformation notches, which are spaced at equal angles around the circumference of the expansion tube.
[0016] By adopting the above technical solution, the opening of the deformation notch makes the expansion tube deformation and expansion smoother. The deformation notch at the rear end of the expansion tube will be reduced. The deformation notch is used for the space required for the corresponding deformation at the end of the expansion tube during deformation, so as not to hinder the deformation of the expansion tube.
[0017] Optionally, the expansion tube includes a deformable portion near the screw head and an insertion portion near the nut, wherein the outer diameter of the deformable portion gradually decreases in the direction away from the insertion portion.
[0018] By adopting the above technical solution, the outer diameter of the deformable part gradually decreases, which is used to ensure that the expansion tube expands outward, rather than shrinks inward or undergoes other irregular deformations.
[0019] Optionally, the expansion tube includes a deformable portion near the screw head and an insertion portion near the nut. The outer diameter of the deformable portion gradually decreases in the direction away from the insertion portion, and the maximum width of the deformation groove is located at the junction of the insertion portion and the deformable portion.
[0020] By adopting the above technical solution, it is ensured that when the two ends of the expansion tube are squeezed and deformed, the expansion tube expands and deforms outward at a specific position, namely the middle area of the deformation groove.
[0021] Optionally, the screw head is formed with a limiting ring groove for inserting the end of the expansion tube.
[0022] By adopting the above technical solution, a limiting ring groove is opened, so that the end of the expansion tube is placed in the limiting ring groove, thereby limiting the end of the expansion tube. This prevents the end of the limiting tube from expanding outward under the extrusion of the screw head, and also prevents the end of the expansion tube from being directly deformed due to pressure when entering the mounting hole, thus limiting its entry.
[0023] In summary, by creating a deformation groove, the expansion tube can deform and bulge outwards at the groove location. During use, the screw head and expansion tube are placed into the corresponding hole, and the nut is screwed into the rod body, causing the screw head to move in the direction of the nut. The screw head squeezes the expansion tube, ultimately pushing the area where the deformation groove is created on the expansion tube to expand and deform, squeezing the hole wall and restricting the expansion bolt to be fixed in the hole. Since the expanded area of the expansion tube is located in the middle area of the hole for installation, the expansion bolt is more stable after installation, the contact between the expansion tube and the hole wall is more secure, and the rod body is more stable. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the expansion bolt structure in an embodiment of this application;
[0025] Figure 2 This is a schematic diagram of the expansion tube structure in an embodiment of this application;
[0026] Figure 3 This is a schematic diagram of the screw structure in an embodiment of this application;
[0027] Figure 4 This is a cross-sectional view of one embodiment of the expansion bolt in this application;
[0028] Figure 5 This is a cross-sectional view of another embodiment of the expansion bolt in this application;
[0029] Figure 6 This is a structural schematic diagram of the expansion tube of the expansion bolt in the outward expansion state in the embodiment of this application.
[0030] Explanation of reference numerals in the attached drawings: 1. Screw; 11. Screw head; 111. Restricting ring groove; 12. Rod body; 2. Nut; 3. Expansion tube; 31. Insertion part; 32. Deformation part; 33. Deformation groove; 34. Deformation notch; 4. Spring washer; 5. Flat washer; 6. Annular limiting edge. Detailed Implementation
[0031] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.
[0032] This application discloses an expansion bolt.
[0033] Reference Figure 1 An expansion bolt includes a screw rod 1, a nut 2, an expansion tube 3, a spring washer 4, and a flat washer 5. The screw rod 1 includes a screw head 11 and a rod body 12, which are coaxial cylinders. The diameter of the screw head 11 is larger than the diameter of the rod body 12. The end of the rod body 12 away from the screw head 11 has an external thread for the nut 2 to be screwed into. The expansion tube 3, the flat washer 5, and the spring washer 4 are sequentially fitted onto the rod body 12 and located between the screw head 11 and the nut 2. The nut 2 restricts the expansion tube 3, the flat washer 5, and the spring washer 4 from detaching from the rod body 12. The outer diameter of the flat washer 5 is larger than the diameter of the screw head 11, and the outer diameter of the spring washer 4 is smaller than the outer diameter of the flat washer 5. The nut 2 completely covers the spring washer 4. The flat washer 5 and the spring washer 4 are standard parts. The openings of the spring washer 4 are staggered and elastic. The sharp corners of the staggered openings of the spring washer 4 penetrate the nut 2 and the flat washer to prevent the nut 2 from loosening.
[0034] Reference Figure 1 and Figure 2 The expansion tube 3 includes an insertion part 31 and a deformation part 32. The outer diameter and inner diameter of the deformation part 32 gradually decrease in the direction away from the insertion part 31. When the expansion tube 3 is placed on the rod body 12, the deformation part 32 is close to the screw head 11 and the insertion part 31 is close to the nut 2. The diameter of the insertion part 31 can be greater than or equal to the diameter of the screw head 11. In this embodiment, the diameter of the screw head 11 can be designed in two specifications depending on the usage method. When the expansion tube 3 is driven in, the diameter of the screw head 11 is slightly smaller than the outer diameter of the expansion tube 3, so that the screw head 11 and the deformation part 32 can be freely inserted, while the insertion part 31 needs to be driven in. When the insertion method is used, the diameter of the screw head 11 can be the same as the diameter of the insertion part 31, and the entire expansion bolt can be inserted together.
[0035] The expansion tube 3 has a deformation groove 33 along its axial direction. The deformation groove 33 penetrates the expansion tube 3 and exposes the area of the rod body 12 corresponding to the deformation groove 33. The deformation groove 33 is opened at one end of the expansion tube 3 near the screw head 11. Specifically, half of the deformation groove 33 is opened in the deformation part 32 and the other half is opened in the insertion part 31. The width of the deformation groove 33 gradually decreases from the middle area to both ends. That is, the maximum width of the deformation groove 33 is located at the junction of the insertion part 31 and the deformation part 32. The end of the deformation groove 33 is spaced apart from the end of the expansion tube 3. That is, the deformation groove 33 does not penetrate the end of the expansion tube 3 along its axial direction.
[0036] There are multiple deformation grooves 33, which are opened at equal angles around the expansion tube 3. In this embodiment, four deformation grooves 33 are specifically opened.
[0037] Meanwhile, when the expansion tube 3 is installed on the shaft 12 and abuts against the shaft head, the area where the external thread is opened on the shaft 12 does not reach the position of the deformation groove 33, that is, the deformation groove 33 will not expose the external thread on the shaft 12.
[0038] The expansion tube 3 has a deformation notch 34 at its end. There are multiple deformation notches 34, which are arranged at equal angles around the circumference of the expansion tube 3. The deformation notches 34 are isosceles trapezoids with large openings. Preferably, the number of deformation notches 34 is more than the number of deformation grooves 33. In this embodiment, there are four deformation grooves 33 and six deformation notches 34.
[0039] In another embodiment, the number of deformation notches 34 may be the same as the number of deformation grooves 33, and in this embodiment, the positions of the four deformation notches 34 correspond one-to-one with the positions of the four deformation grooves 33.
[0040] Reference Figure 3 and Figure 4 The screw head 11 is formed with a limiting ring groove 111 for the end of the expansion tube 3 to be inserted. The end of the expansion tube 3 abuts against the bottom of the limiting ring groove 111. In this embodiment, the cross section of the limiting ring groove 111 is an isosceles trapezoid, so that when the expansion tube 3 deforms, there is enough space in the limiting ring groove 111 for the expansion tube 3 to deform and move.
[0041] Reference Figure 3 and Figure 5 In another embodiment, an annular limiting edge 6 protrudes from the screw head 11. The annular limiting edge 6 cooperates with the rod body 12 to form a corresponding limiting annular groove 111. The thickness of the annular limiting edge 6 can be lower, so that the annular limiting edge 6 can also protrude outward and abut against the hole wall when the expansion tube 3 protrudes outward. At the same time, in a further embodiment, the annular limiting edge 6 can be formed on the screw head 11 using a material that is easier to deform. Alternatively, multiple notches can be opened at equal angles on the annular limiting edge 6 to facilitate the deformation of the annular limiting edge 6.
[0042] The implementation principle of an expansion bolt according to an embodiment of this application is as follows: The screw head 11 and expansion tube 3 of the screw rod 1 are inserted into the hole for installation. The flat washer 5, spring washer 4, and nut 2 are installed onto the rod body 12 in sequence. As the nut 2 is continuously screwed in, it causes the screw rod 1 to move axially outward, while the expansion tube 3 remains stationary. The screw head 11 squeezes the expansion tube 3, eventually causing the area where the deformation groove 33 is formed in the expansion tube 3 to expand outward. The expanded expansion tube 3 tightly abuts against the hole wall and fills the entire hole. At this point, the expansion bolt is fixed. Refer to Figure 6 During installation, an outward-expanding groove can be cut into the inner wall of the hole to allow the expansion tube 3 to expand and fill better, forming a snap-fit-like restriction.
[0043] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. An expansion bolt, characterized in that: The device includes a screw (1), a nut (2), and an expansion tube (3). The screw (1) includes a screw head (11) and a rod body (12). The end of the rod body (12) away from the screw head (11) is threadedly engaged with the nut (2). The expansion tube (3) is fitted onto the rod body (12) and is sandwiched between the screw head (11) and the nut (2). The screw head (11) abuts against the expansion tube (3). The expansion tube (3) has a deformation groove (33) along the axial direction. There are multiple deformation grooves (33), and the multiple deformation grooves (33) are equally spaced around the circumference of the expansion tube (3).
2. The expansion bolt according to claim 1, characterized in that: The deformation groove (33) is formed at one end of the expansion tube (3) near the screw head (11).
3. The expansion bolt according to claim 1, characterized in that: The end of the deformation groove (33) is spaced apart from the end of the expansion tube (3).
4. The expansion bolt according to claim 1, characterized in that: The width of the deformation groove (33) gradually decreases from the middle area to both ends.
5. The expansion bolt according to claim 3, characterized in that: The expansion tube (3) has a deformation notch (34) at its end. There are multiple deformation notches (34), and the multiple deformation notches (34) are arranged at equal angles around the circumference of the expansion tube (3).
6. The expansion bolt according to claim 1, characterized in that: The expansion tube (3) includes a deformable portion (32) near the screw head (11) and an insertion portion (31) near the nut (2), wherein the outer diameter of the deformable portion (32) gradually decreases in the direction away from the insertion portion (31).
7. The expansion bolt according to claim 4, characterized in that: The expansion tube (3) includes a deformable part (32) near the screw head (11) and an insertion part (31) near the nut (2). The outer diameter of the deformable part (32) gradually decreases in the direction away from the insertion part (31), and the maximum width of the deformation groove (33) is located at the junction of the insertion part (31) and the deformable part (32).
8. The expansion bolt according to claim 1, characterized in that: The screw head (11) is formed with a limiting annular groove (111) for inserting the end of the expansion tube (3).