Anti-falling expansion bolt

Abstract

The utility model discloses an anti-drop expansion bolt, which is suitable for fixedly installing a workpiece on a wall body hole, used parts are consistent with those of a conventional expansion bolt, and the anti-drop expansion bolt comprises a screw rod, a nut, a gasket and an expansion pipe. Only the tail of the screw is a circular-truncated-cone-shaped rod cap, a protruding tip is machined on the outer surface of the expansion pipe, and the outer diameter of the rod cap corresponds to the outer diameter of the protruding tip and is not greatly different from the outer diameter of the protruding tip. Or an arch is machined on the expansion pipe, and the convex tip is located on the outer surface of the arch. The spur and the arch are in a continuous or discontinuous circular ring shape or a spiral shape. The convex tips are embedded into the inner wall of the wall body hole to achieve anti-skid and anti-drop effects, production of all parts does not increase procedures, and manufacturing cost is low.

Description

Technical Field

[0001] This utility model applies to the field of fasteners and relates to the fastening of workpieces on walls, specifically an expansion bolt for fixed installation on walls. Background Technology

[0002] Expansion bolts are commonly used fasteners for installing workpieces on walls. A typical expansion bolt structure is shown in the attached image. Figure 1 As shown, the expansion bolt is assembled from a screw 1, a nut 2, a washer 3, and an expansion tube 4. The tail of the screw is machined with a tapered surface, and the expansion tube has a notch at its mating point with the tapered surface. In use, tightening the nut 2 moves the screw 1 to the right, bringing the tapered surface into contact with the expansion tube 4, causing it to expand and its outer diameter to increase. The notch facilitates the outward expansion of the expansion tube. The tightening principle of this expansion bolt relies on the friction between the expansion tube and the inner wall of the wall hole. This friction originates from the elastic force generated by the tapered surface at the tail of the screw, causing the expansion tube to expand. Over time, the elastic stress gradually disappears, and the friction between the expansion tube and the inner wall of the wall hole gradually decreases, weakening the force holding the workpiece to the wall and causing it to loosen.

[0003] There are many patent applications for expansion bolts, such as CN112360857A for an easy-to-install combination expansion bolt, CN215720052U for an easily detachable expansion bolt, and CN211174927U for a recyclable expansion bolt, which mainly consider the usage perspective. Other applications, such as CN105889246A for an anti-slip expansion bolt, CN109322889B for an anti-loosening expansion bolt, and CN209705022U for an anti-loosening expansion bolt, mainly focus on preventing... From an application perspective, patents such as CN209398693U (an expansion bolt suitable for large-diameter holes) and CN219327713U (an expansion bolt for aerated concrete blocks) primarily consider the application environment. Patents like CN102758818B (scissor-type expansion bolt), CN105805116B (double-expansion tube expansion bolt), CN206280340U (an embedded expansion bolt hook), and CN205689543U (a novel six-point expansion bolt) mainly focus on structural improvements. These patents rarely consider manufacturing costs; after all, besides ease of use and anti-loosening features, cost is a crucial competitive factor in the market competitiveness of expansion bolts.

[0004] Appendix Figure 1 The manufacturing of expansion bolts includes: 1) cold heading and threading of nuts, 2) cold heading of washers, 3) notching of expansion tubes, 4) cold heading and thread rolling of screws, and 5) assembly. Typically, nuts and washers are standard parts and are purchased in bulk from external suppliers; the focus is on manufacturing screws and expansion tubes. Utility Model Content

[0005] The utility model solves the technical problem: provide a kind of anti-expansion bolt, production manufacturing procedure same conventional expansion bolt, while strengthening its anti-expansion function, realize low-cost production.

[0006] The utility model adopts the technical scheme: the utility model anti-expansion bolt used component and conventional expansion bolt are identical, including screw rod, nut, washer and expansion pipe.Different, the tail portion of screw rod is the rod cap of circular table shape;The outer surface of expansion pipe is processed with convex tip;The outer diameter of rod cap corresponds with the outer diameter of convex tip, and the difference between the two is not big.The sharp angle of convex tip is not more than 90 °, and it is convenient to embed in the inner wall of wall hole.

[0007] Further, the expansion pipe is processed with arch, and the convex tip is located on the outer surface of the arch. When the expansion pipe is deformed under pressure, it deforms according to the unstable direction of the arch.

[0008] Further, the convex tip and the arch are circular or spiral, and the pitch of the spiral is preferably small.

[0009] Further, the convex tip is a symmetrical structure, i.e. symmetrical along the vertical line of the outer surface of the expansion pipe, and the sharp angle is preferably 40-60 °.

[0010] Further, the convex tip is an asymmetrical structure. In the direction of pulling out the screw rod, the convex tip surface of the convex tip is a vertical surface. In the direction of inserting the screw rod, the convex tip surface of the convex tip is an inclined surface. This convex tip structure is more conducive to fixing the expansion pipe.

[0011] Further, the convex tip is a continuous or intermittent spiral or circular structure.

[0012] The utility model has the beneficial effects that: the utility model embeds the convex tip on the outer surface of the expansion pipe into the inner wall of the wall hole to achieve anti-slip and anti-expansion fixation. The production of the screw rod and the expansion pipe does not increase the process, and does not use special equipment, so the manufacturing cost is low, and it has market competitiveness. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a common expansion bolt structure schematic diagram;

[0014] Figure 2 is a structure schematic diagram of embodiment 1;

[0015] Figure 3 is a structure schematic diagram of embodiment 2;

[0016] Figure 4 is a convex tip structure schematic diagram of embodiment 3;

[0017] In the figure: 1-screw rod, 2-nut, 3-washer, 4-expansion pipe, 5-rod cap, 6-convex tip, 7-arch. DETAILED DESCRIPTION Example 1

[0018] The expansion bolt structure in this embodiment is shown in the attached figure. Figure 2 As shown, compared to conventional expansion bolts, this also includes a screw 1, a nut 2, a washer 3, and an expansion tube 4. The tail of a conventional expansion bolt is tapered, while in this embodiment, the tail of the screw 1 is a frustum-shaped cap 5. Conventional expansion bolts have notches machined into the expansion tube, while in this embodiment, the outer surface of the expansion tube 4 is machined with a protrusion 6. The protrusion 6 on the outer surface of the expansion tube 4 can be multiple single rings, i.e., circular rings, or spiral shapes. From a production and usage perspective, spiral protrusions 6 are preferable.

[0019] In this embodiment, the expansion bolt is inserted into the wall hole from its tail end. After the workpiece is installed, the nut 2 is tightened, causing the nut 2 to move to the left and the screw 1 to move to the right. When both ends of the expansion tube 4 contact the rod cap 5 and the washer 3, the nut is tightened further, causing the expansion tube 4 to deform under pressure. The inner surface of the expansion tube 4 is supported by the screw 1, forcing the expansion tube 4 to deform outward circumferentially, thereby allowing the protrusion 6 to embed into the inner wall of the wall hole, thus fixing the expansion bolt. Even if the preload between the nut and the screw disappears after a long time, and the elastic expansion of the expansion tube disappears, the expansion tube cannot be pulled out of the wall hole due to the embedding of the protrusion, thus achieving the loosening or anti-loosening of the expansion bolt. Example 2

[0020] The expansion bolt structure in this embodiment is shown in the attached figure. Figure 3 As shown, compared to Embodiment 1, only the structure of the expansion tube is adjusted. In Embodiment 1, the deformation of the expansion tube during use is random. If the gap between the expansion tube and the screw is large, the expansion tube may deform inward, thereby increasing the outward movement of the screw. In this embodiment, an arched structure 7 is set below the protrusion, that is, a protrusion 6 is set on the outer surface of the arched structure 7. The arched structure 7 corresponds to the protrusion 6. If the protrusion is annular, the arched structure is also annular; if the protrusion is spiral, the arched structure is also spiral.

[0021] In this embodiment, when the nut is tightened, the expansion tube 4 is deformed under pressure. The deformation of the expansion tube 4 will preferentially deform outward along the direction of the arch, thereby ensuring that the protrusion on the expansion tube is embedded in the inner wall of the hole in the wall, thus achieving the fixing of the expansion bolt. Example 3

[0022] In the above embodiments, the protrusion adopts a symmetrical structure, that is, it is symmetrical along the vertical line of the outer surface of the expansion tube, and the sharp angle of the protrusion should not exceed 90°. The larger the sharp angle of the protrusion, the longer the service life of the mold during production, but the more difficult it is to embed the protrusion into the inner wall of the wall hole when installing it in the wall hole. The smaller the sharp angle of the protrusion, the easier it is to embed the protrusion into the inner wall of the wall hole, but the service life of the mold is short. The sharp angle of the protrusion should preferably be 40-60°.

[0023] In this embodiment, the protrusion has an asymmetrical structure, as shown in the attached figure.Figure 4 As shown, the convex tip surface is a vertical surface in the direction of the screw rod being pulled out, and is an inclined surface in the direction of the screw rod being inserted. The structure ensures that the sharp angle of the convex tip is less than 90°, and after the convex tip is embedded in the inner wall of the hole in the wall, it is difficult to be pulled out, thereby realizing the fixing and anti-dropping of the expansion bolt.

[0024] It should be noted that:

[0025] 1) The outer diameter of the rod cap 5 corresponds to the outer diameter of the convex tip 6, and the difference between the two is not large. If the outer diameter of the convex tip 6 is excessively larger than the outer diameter of the rod cap 5, it is difficult to insert into the hole in the wall, and if the outer diameter of the convex tip 6 is excessively smaller than the outer diameter of the rod cap 5, it is difficult for the convex tip to be embedded in the inner wall of the hole in the wall. That is, the outer diameter of the convex tip 6 and the outer diameter of the rod cap 5 both correspond to the inner diameter of the hole in the wall.

[0026] 2) For the embodiment 1, there is no case of only expansion of the pipe and compression without deformation, which is determined by the stability of the expansion pipe. For the thin-walled and slender expansion pipe, the stability is poor when being compressed, and unstable deformation will inevitably occur. The unstable deformation is mostly bending, and when the expansion pipe is bent and deformed, the inside is limited by the screw rod and can only deform outward, the convex tip is spiral, and there is always a convex tip embedded in the inner wall of the hole in the wall. For the arch in the embodiment 2, the arch utilizes the instability of the expansion pipe, so that the arch can be deformed outward under pressure.

[0027] 3) The convex tip and the arch of the utility model are preferably spiral and arc, which is beneficial to the demolding of the expansion pipe in rotation, but does not deny the circular ring, only the requirement for the mold is higher during demolding. From the deformation angle, the pitch of the arch is preferably small, otherwise it becomes the resistance of compression, and the stability of the expansion pipe under pressure is increased. The optimal arch adopts a circular ring.

[0028] 4) In the above three embodiments, the convex tip is continuous spiral or circular ring, in order to increase the service life of the mold, it can also be intermittent spiral or circular ring, which does not affect the deformation and embedding of the expansion pipe in the hole in the wall.

[0029] The utility model utilizes the convex tip on the outer surface of the expansion pipe to embed in the inner wall of the hole in the wall to realize the anti-skid and anti-dropping, even if the pre-tightening force of the screw disappears and the elastic stress of the expansion pipe disappears, the convex tip is embedded in the inner wall of the hole in the wall, and the resistance can realize the fixing of the expansion bolt.

[0030] The utility model expands pipe directly processes and forms on the thread rolling machine, the thread rolling machine is the special equipment of processing screw rod, needs to change the roller mould to the processing mould of the utility model expansion pipe when producing expansion pipe, can according to rotating support in expansion pipe, the specific structure can see the expansion pipe processing device of applicant's same day application. Expansion pipe material mostly uses 08 or 10 steel, belongs to low carbon low strength steel, is easy to cold deformation. The utility model expands pipe after cold working, utilizes cold deformation to increase the strength of expansion pipe convex tip, is convenient for convex tip to embed in the hole inner wall of wall body. The utility model expands pipe compared with the expansion pipe of conventional expansion bolt, uses convex tip processing to replace gap processing, does not increase processing procedure. The manufacturing technology of the utility model screw rod is same with the screw rod manufacturing technology of conventional expansion bolt, still is cold upsetting after rubbing silk, just the structure of screw rod tail end cold upsetting is different. Nut and washer still adopt standard parts, also do not increase processing procedure. So, the utility model expansion bolt compared with conventional expansion bolt, does not increase processing procedure, and the processing of screw rod and expansion pipe does not use special equipment, just mould changes, low production cost, is difficult to pull out after being fixed to the hole of wall body, good fixity, more has market competitiveness.

Claims

1. A non-loosening expansion bolt comprising a screw rod, a nut, a washer and an expansion tube, characterized in that: The tail of the screw is a round-taip-shaped rod cap (5); the outer surface of the expanded tube is processed with a convex tip (6); the outer diameter of the rod cap (5) corresponds to the outer diameter of the convex tip (6); the acute angle of the convex tip (6) is not more than 90°.

2. A non-releasing expansion bolt according to claim 1 wherein: An arch (7) is processed on the expanded tube, and the convex tip (6) is located on the outer surface of the arch (7).

3. A non-releasing expansion bolt according to claim 1 or 2, wherein: The convex tip (6) is circular or spiral.

4. The anti-backout expansion bolt of claim 1, wherein: The convex tip (6) is a symmetric structure, and the acute angle is 40-60°.

5. The anti-backout expansion bolt of claim 1, wherein: The convex tip (6) is an asymmetric structure, and the convex tip surface of the convex tip (6) is a vertical surface in the pulling direction of the screw, and the convex tip surface of the convex tip (6) is an inclined surface in the plugging direction of the screw.

6. A non-releasing expansion bolt according to claim 1 wherein: The convex tip (6) is a continuous or discontinuous structure.

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