Sawtooth expansion bolt
By designing expansion bolts with serrated structures, the problems of easy loosening and insufficient pull-out resistance of traditional expansion bolts in gaps and holes are solved, achieving higher pull-out strength and reduced vibration displacement. It is suitable for anchoring brittle materials such as concrete, red brick, porous brick, and aerated concrete blocks.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 秦睿锋
- Filing Date
- 2025-06-04
- Publication Date
- 2026-05-12
AI Technical Summary
Traditional expansion bolts cannot provide effective tensile force in pores and holes, are prone to loosening, have insufficient pull-out resistance, and are prone to causing substrate cracking under vibration. Chemical anchors are complex to install and have a long curing time.
A sawtooth expansion bolt is designed, which uses an expansion tube with outwardly bent sawtooths at the head and middle expansion structure. A composite expansion mechanism drives the tapered bolt to open the expansion structure, forming an anchoring effect and enhancing the anchoring performance.
It increases tensile strength by more than 40%, reduces displacement in vibration tests by 60%, and enhances anchoring effect in brittle materials.
Smart Images
Figure CN224229042U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of building fastener technology, and in particular to an expansion bolt with a serrated structure, suitable for anchoring brittle materials such as concrete, red brick, porous brick, aerated concrete block, and stone. Background Technology
[0002] The shortcomings of traditional expansion bolts: Ordinary red bricks, hollow bricks, porous bricks, and aerated concrete block walls have many gaps. Traditional expansion bolts cannot effectively provide tensile force in the gaps and holes. They rely on frictional expansion, which makes them easy to loosen under vibration. The smooth bolt body has insufficient interlocking force with the substrate, and the pull-out resistance is limited by the strength of the expansion plate.
[0003] The shortcomings of the existing improvement solutions are: the voids in the holes cannot provide effective tensile force, the strength of the air block substrate is insufficient, the threaded expansion bolts are prone to causing stress concentration and cracking of the substrate, and the chemical anchors are complicated to construct and have a long curing time. Summary of the Invention
[0004] The purpose of this invention is to provide an expansion bolt with a serrated structure to overcome the problems existing in the prior art.
[0005] To achieve the above objectives, this utility model provides the following technical solution:
[0006] This utility model provides a serrated expansion bolt, including an expansion tube. The expansion tube has a head expansion structure and a middle expansion structure that can open in both directions around its perimeter. The head expansion structure has outwardly bent serrations distributed on both sides. The top of the head expansion structure has an outwardly bent guide surface. The head expansion structure is fixedly connected to the upper circular tube by a first bend that sinks downward on the expansion surface. The upper circular tube is fixedly connected to the middle expansion structure by a second bend that sinks upward on the expansion surface. A lower circular tube is provided on the lower side of the middle expansion structure. The middle expansion structure and the lower circular tube are fixedly connected by a third inward bend.
[0007] Furthermore, a tapered screw column passes through the center of the expansion tube, a gasket is provided on the lower side of the expansion tube, a spring washer is provided on the lower side of the gasket, and a nut is provided on the lower side of the spring washer. The expansion tube, gasket, and spring washer are sequentially fitted onto the outer wall of the tapered screw column, and a nut is installed at the rear end of the tapered screw column.
[0008] Furthermore, the head expansion structure has serrations symmetrically distributed on both sides, and the bending angle between the serrations and the head expansion structure is 45°.
[0009] Furthermore, the guide surface bends outward at an angle of 45°.
[0010] Furthermore, the third bend is V-shaped.
[0011] Beneficial effects:
[0012] This utility model provides a serrated expansion bolt. The head of the expansion tube is bent at 45° to provide expansion conditions. The surface of the expansion tube is provided with an axial serrated structure. The serrated head expansion structure and the middle expansion structure sink inward through bending to adapt to the diameter of the hole. The angle between the serrations and the tube tangent is 45°, the serration angle is 90°, and the tooth height is 0.8mm. Through the action of the composite expansion mechanism, the tapered bolt drives the upper part to open towards the head, and the bolt pressure is transmitted to the middle bent part, causing the middle expansion structure to open towards the tail, forming a front and rear anchoring effect. Compared with ordinary expansion bolts of the same specification, the tensile strength is increased by more than 40%, and the displacement in vibration testing is reduced by 60%. Attached Figure Description
[0013] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0014] Figure 1 This is a schematic diagram of the overall structure of the sawtooth expansion bolt of this utility model;
[0015] Figure 2 This is a schematic diagram of the overall structure of the sawtooth expansion bolt of this utility model.
[0016] In the diagram: 1-expansion tube, 2-serration, 3-first bend, 4-second bend, 5-middle expansion structure, 6-third bend, 7-head expansion structure, 8-guide surface, 9-lower round tube, 10-upper round tube, 11-washer, 12-spring washer, 13-nut, 14-conical screw column. Detailed Implementation
[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0018] Example 1
[0019] This utility model provides a serrated expansion bolt, including an expansion tube 1. The expansion tube 1 is provided with a head expansion structure 7 and a middle expansion structure 5 that can open in both directions. The head expansion structure 7 has outwardly bent serrations 2 distributed on both sides. The top of the head expansion structure 7 has an outwardly bent guide surface 8. The head expansion structure 7 is fixedly connected to the upper circular tube 10 through a first bend 3 that sinks downward on the expansion surface. The upper circular tube 10 is fixedly connected to the middle expansion structure 5 through a second bend 4 that sinks upward on the expansion surface. The lower side of the middle expansion structure 5 is provided with a lower circular tube 9. The middle expansion structure 5 and the lower circular tube 9 are fixedly connected by an inward third bend 6.
[0020] The expansion tube includes a serrated first bend 3, a second bend 4, a middle expansion structure 5, a V-shaped bend 6, a head expansion structure 7, a guide surface 8, a lower circular tube 9, an upper circular tube 10, and the expansion tube 1 is an integral structure.
[0021] An expansion tube 1 has a conical screw column 14 running through its center. A gasket 11 is provided on the lower side of the expansion tube 1. A spring washer 12 is provided on the lower side of the gasket 11. A nut 13 is provided on the lower side of the spring washer 12. The expansion tube 1, gasket 11, and spring washer 12 are sequentially fitted onto the outer wall of the conical screw column 14, and the nut 13 is installed at the rear end of the conical screw column 14.
[0022] The head expansion structure 7 has serrations 2 symmetrically distributed on both sides, and the bending angle between the serrations 2 and the head expansion structure 7 is 45°.
[0023] The guide surface 8 bends outward at an angle of 45°.
[0024] The third bend is V-shaped.
[0025] Pre-fabricated serration process: Continuous serrations with a 2mm spacing are formed on the expansion surface of the plug body using stamping. Expansion sleeve grooving: A 7mm*2mm rectangular groove is cut at the bending point. Bending: The serrated expansion surface is stamped inward and bent outward.
[0026] Working Principle and Usage: In this embodiment, the sawtooth expansion bolt is used by first drilling a hole with a diameter of 14.5mm and a depth of 60mm, inserting the expansion bolt, and then applying a torque of 30Nm to fully expand the expansion sleeve 1. The sawtooth 2 uses a wavy continuous curved surface to form a mechanical interlock with the substrate. The head expansion structure 7 and the middle expansion structure 5 with sawtooth 2 bend inward to adapt to the diameter of the hole. The angle between the sawtooth 2 and the tube tangent is 45°, the sawtooth angle is 90°, and the tooth height is 0.8mm. Through the action of the composite expansion mechanism, the tapered bolt drives the upper part to open towards the head, and the bolt pressure is transmitted to the middle bending part, causing the middle expansion structure to open towards the tail, forming a front-to-back anchoring effect. This utility model is suitable for anchoring brittle materials such as concrete, red brick, porous brick, aerated concrete blocks, and stone.
[0027] As can be seen from the above embodiments, this utility model provides a serrated expansion bolt. The head of the expansion tube is bent at 45° to provide expansion conditions. An axial serrated structure is provided on the surface of the expansion tube. The serrated head expansion structure and the middle expansion structure sink inward through bending to adapt to the diameter of the hole. The angle between the serration and the tube tangent is 45°, the serration angle is 90°, and the tooth height is 0.8mm. Through the action of the composite expansion mechanism, the tapered bolt drives the upper part to open towards the head, and the bolt pressure is transmitted to the middle bending part, causing the middle expansion structure to open towards the tail, forming a front and rear anchoring effect. Compared with ordinary expansion bolts of the same specification, the tensile strength is increased by more than 40%, and the displacement is reduced by 60% in vibration tests.
[0028] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A serrated expansion bolt, characterized in that, The device includes an expansion tube (1), which has a head expansion structure (7) and a middle expansion structure (5) that can open in both directions. The head expansion structure (7) has outwardly bent serrations (2) on both sides. The head expansion structure (7) has an outwardly bent guide surface (8) at the top. The head expansion structure (7) is fixedly connected to the upper circular tube (10) through a first bend (3) that sinks downward on the expansion surface. The upper circular tube (10) is fixedly connected to the middle expansion structure (5) through a second bend (4) that sinks upward on the expansion surface. The middle expansion structure (5) has a lower circular tube (9) on its lower side. The middle expansion structure (5) and the lower circular tube (9) are fixedly connected through a third bend (6) that sinks inward.
2. The serrated expansion bolt according to claim 1, characterized in that, The expansion tube (1) has a conical screw column (14) running through its center. A gasket (11) is provided on the lower side of the expansion tube (1). A spring washer (12) is provided on the lower side of the gasket (11). A nut (13) is provided on the lower side of the spring washer (12). The expansion tube (1), gasket (11), and spring washer (12) are sequentially fitted onto the outer wall of the conical screw column (14), and the nut (13) is installed at the rear end of the conical screw column (14).
3. The serrated expansion bolt according to claim 2, characterized in that, The head expansion structure (7) has serrations (2) symmetrically distributed on both sides, and the bending angle between the serrations (2) and the head expansion structure (7) is 45°.
4. The serrated expansion bolt according to claim 1, characterized in that, The guide surface (8) bends outward at an angle of 45°.
5. The serrated expansion bolt according to claim 2 or 4, characterized in that, The third bend (6) is V-shaped.