A self-expanding, flared stent
By using a two-lobed expansion plate design and a necking structure, the self-expanding expansion component solves the problems of easy breakage and high cost of expansion plates, achieving high strength, low cost expansion stability and mechanical engagement anchoring, which is suitable for various building anchoring scenarios.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 瞿滨
- Filing Date
- 2025-07-18
- Publication Date
- 2026-06-23
AI Technical Summary
Existing self-expanding anchors have expansion plates that are prone to breakage, difficult to expand, and costly, which limits their application in general structural engineering. Traditional expansion anchors are also unsuitable for important structures due to the attenuation of expansion force.
The self-expanding expansion piece adopts a two-lobed expansion plate design, combined with a necked base and a notch structure. The necked structure allows the expansion plate to unfold under the action of axial thrust and rotational torque, forming a trumpet-shaped expansion base. Combined with a hardened cutting head, it cuts into the substrate to achieve mechanical engagement and anchoring.
It improves the bending strength of the expansion plates, reduces production costs, ensures expansion stability and anchoring reliability, is suitable for existing installation equipment, requires no large-scale modification, and is easy to promote and apply.
Smart Images
Figure CN224396870U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of mechanical anchor bolt technology, and in particular to a self-expanding bottom expansion member. Background Technology
[0002] Mechanical anchors are building fasteners that achieve anchoring through mechanical means, including expansion anchors and self-expanding anchors.
[0003] Expansion anchors: By applying torque or impact force, the expansion plate expands and squeezes the hole wall, using the friction force generated by the friction effect as the main anchoring force;
[0004] Self-expanding anchors: These require hardened cutting edges on the expansion plate capable of cutting the substrate. This allows the expansion plate to be inserted into the substrate's expanded hole during anchor installation, forming a mechanical lock key with mechanical engagement force as the primary anchoring force. The expansion plate must possess sufficient strength to withstand the impact of the stall torque during expansion; otherwise, it will be torn apart by the stall torque, resulting in failed expansion.
[0005] It is difficult to embed hard blades on conventional expansion plates with four or more lobes because when expanding the base, expansion plates with four or more lobes are insufficient to overcome the locking torque caused by the substrate (usually hard objects and steel bars in concrete), which can easily lead to the expansion plates with four or more lobes being torn apart, resulting in anchoring failure.
[0006] Existing technologies enhance the strength of self-expanding anchors by increasing the wall thickness of the expansion sleeve and expansion plates. However, this significantly increases the complexity of the manufacturing process and substantially raises costs, making them tens or even hundreds of times more expensive than traditional expansion anchors. Consequently, a self-expanding anchor with excellent anchoring performance is excluded from general structural engineering projects. Furthermore, the use of expansion anchors (JGT160-2017 Mechanical Anchors for Concrete) is prohibited in general structural engineering. This leaves the application of self-expanding anchors in a perpetually awkward position. Utility Model Content
[0007] The purpose of this utility model is to provide a self-expanding expansion component, which consists of a cylindrical support section and an expansion plate. The expansion plate adopts a two-lobed expansion plate design, combined with a necked base and a notch structure, to solve the problems of easy breakage, difficult expansion and high cost of the expansion plate in the prior art, and has the advantages of high strength, easy expansion and low cost.
[0008] To achieve the above objectives, the solution of this utility model is: a self-expanding expansion member, which has a cylindrical structure and is used in conjunction with a screw with a conical head;
[0009] The front section of the self-expanding expansion member is the expansion section, and the rear section is the support section;
[0010] The expansion section includes two arc-shaped expansion plates, and the head of the expansion plate is equipped with an expansion blade for cutting into the substrate;
[0011] The base of the expansion piece connects its head and support section, and circumferentially extending notches are formed on both sides of the base, making the base appear constricted relative to the head and support section.
[0012] When the expansion plate is subjected to external force and moves axially on the cone head, its base deforms, causing the head to rotate outward around the constricted neck. At the same time, the two wings of the head deform outward, gradually increasing the curvature of the head to match the curvature of the outer circumference of the cone head.
[0013] Furthermore, the self-expanding bottom expansion member has an axisymmetric structure.
[0014] Furthermore, in the expansion piece, the arc length of the base is 1 / 5 to 1 / 2 of the arc length of the head.
[0015] Furthermore, in the expansion piece, the height of the base is 1 / 5 to 1 / 2 of the height of the head.
[0016] Furthermore, the inner diameter of the front end of the expansion section is d, and the maximum outer diameter of the cone is D. Before the expansion plate expands its bottom, d < D; after the expansion plate expands its bottom, d = D.
[0017] Furthermore, before the expansion sheet is expanded, the orthographic projection of the expansion sheet head is rectangular, and after the expansion sheet is expanded, it becomes trapezoidal.
[0018] Furthermore, the orthographic projection front view of the notch is a rectangle.
[0019] Furthermore, on the expansion section, the circumferential gap between the heads of the two expansion plates is 0~5mm.
[0020] Furthermore, the wall thickness δ of the expansion piece is 2~5mm.
[0021] Furthermore, the underreaming tool is made of cemented carbide or diamond.
[0022] After adopting the above solution, the beneficial effects of this utility model's self-expanding expansion member with a two-lobed expansion structure are as follows:
[0023] 1. The expansion plates have high bending strength along the chord length, ensuring the stability of the expanded base:
[0024] When made of the same materials, the strength of the two-lobed expansion piece of this invention is significantly higher than that of traditional four-lobed or more-lobed expansion pieces. When expanding the bottom hole, its bending strength is four times that of the four-lobed expansion piece, ensuring sufficient torque for the expansion piece during the expansion process. This solves the long-standing problem of insufficient strength when expansion pieces with hard blades are used for bottom expansion, effectively preventing the expansion piece from tearing due to insufficient strength.
[0025] 2. Easy to expand:
[0026] The fewer the number of expansion plates, the greater the arc length of each expansion plate, and the more difficult it is to expand. This invention features notches on both sides of the base of the expansion plate, making the base necked relative to the head and sleeve body. The necked shape facilitates the outward rotation and expansion of the head, while the notches allow the sides of the expansion plate head to be free relative to the sleeve body; that is, the two wings of the head can expand freely under force, without being restricted by the sleeve body.
[0027] During installation, the expansion of the cone head causes the base of the necking structure to undergo elastic deformation preferentially. Under the combined action of axial thrust and rotational torque, the head is forced to rotate outward around the necking point. At the same time, under the combined action of the cone head thrust and the reaction force of the base material, the two wings of the head deform outward, and the radius of curvature gradually increases to match the outer circumference of the cone head, forming a trumpet-shaped expanding base structure. The entire expansion process is smoother and more efficient.
[0028] 3. Low production cost:
[0029] The production cost of this self-expanding underrun expansion component is very close to that of the sleeve in traditional expansion anchors, and far lower than the cost required to increase the wall thickness. It overcomes the limitation of traditional expansion anchors where the sleeve requires increased wall thickness to improve strength. The lower price creates favorable conditions for the widespread adoption of the superior anchoring performance of the self-expanding underrun expansion component. When this highly safe and reliable product can enter the market at a lower cost, its safety performance will benefit more fields and users, fully demonstrating its important social value.
[0030] 4. High versatility:
[0031] The self-expanding expansion member of this invention can be adapted to the screw of conventional expansion anchors. This feature allows the self-expanding expansion member to be easily integrated into the existing building anchoring system without requiring large-scale modifications to existing installation equipment and processes, making it easy to promote and use. Attached Figure Description
[0032] Figure 1 This is an assembly drawing of the self-expanding bottom expansion member and the screw according to an embodiment of the present invention;
[0033] Figure 2 This is a schematic diagram of the structure of the self-expanding expansion member and the screw in one embodiment of this utility model;
[0034] Figure 3 This is a front view of a self-expanding bottom expansion member according to an embodiment of this utility model;
[0035] Figure 4 This is a top view of a self-expanding bottom expansion member according to an embodiment of this utility model;
[0036] Figure 5 yes Figure 4 View from direction A;
[0037] Figure 6 yes Figure 4 BB section view;
[0038] Figure 7 This is a perspective view of the self-expanding expansion member of an embodiment of the present invention before and after expansion;
[0039] Figure 8 This is a side view of the self-expanding expansion member of an embodiment of the present invention before and after expansion;
[0040] Figure 9 This is a schematic diagram of the bottom expansion process of a self-expanding bottom expansion component according to an embodiment of this utility model;
[0041] Figure 10 This is a schematic diagram of a self-expanding bottom expansion component formed by pressing steel plate according to an embodiment of the present invention.
[0042] Label Explanation:
[0043] 1. Self-expanding bottom expansion component;
[0044] 2. Expanding section; 21. Expanding plate; 211. Head; 212. Base; 213. Notch; 214. Groove; 215. Gap; 22. Under-reaming cutter head;
[0045] 3. Support section;
[0046] 4. Screw; 41. Cone head;
[0047] 5. Substrate; 51. Straight hole. Detailed Implementation
[0048] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0049] This utility model provides a self-expanding bottom expansion member 1, such as Figures 1 to 10 As shown, the self-expanding expansion component 1 is used in conjunction with a commonly available screw 4 with a conical head 41 to achieve self-expanding and expansion effects. The self-expanding expansion component 1 has an axisymmetric structure, which ensures uniform force distribution during installation and use, effectively preventing deformation or damage caused by uneven force distribution.
[0050] Regarding hole enlargement:
[0051] like Figure 2As shown, the front section of the self-expanding expansion member 1 is the expansion section 2, which is used to enlarge the hole in the substrate 5. The expansion section 2 can smoothly form a hole that meets the requirements on the substrate 5 during the installation process. The rear section of the self-expanding expansion member 1 is the support section 3, which is used to provide support for the rod part of the screw 4.
[0052] The expansion section 2 has a two-part structure, including two arc-shaped expansion plates 21. Each expansion plate 21 consists of a head 211 and a base 212 connecting the head 211 and the support section 3. The head 211 is provided with a bottom-expanding cutter head 22, which is used to cut into the substrate 5 to provide the key cutting force for the hole expansion operation.
[0053] On the expansion section 2, the circumferential gap 215 between the heads 211 of the two expansion pieces 21 is 0~5mm. Even with a gap 215 of 0mm, the two expansion pieces 21 are not a single piece and can still unfold. If the gap 215 is too large, it will reduce the arc length of the expansion piece 21, decrease its bending strength, and also lead to a decrease in anchoring performance. Therefore, this gap 215 should be as small as possible.
[0054] The self-expanding expansion member 1 in this case can be manufactured based on the base pipe used in the sleeve of a conventional expansion anchor, without increasing material consumption and production costs. Therefore, the wall thickness range of its expansion section 2 can be the same as that of the sleeve of a conventional expansion anchor, typically 2 to 5 mm.
[0055] The two-part design of this utility model, while maintaining the same bending strength, can significantly reduce production costs compared to the existing design that increases the sleeve wall thickness, as shown in Table 1.
[0056]
[0057] Traditional self-expanding anchors require an increased wall thickness (4.5mm) in the sleeve to achieve the bending strength needed for expansion, inevitably increasing manufacturing costs. This invention, however, allows the expansion component to easily achieve the same bending strength standard as traditional self-expanding anchors without increasing wall thickness, and without additional cost. From the perspective of manufacturing cost per anchor, the difference between traditional self-expanding anchors and this invention may not be significant. However, in practical applications, such as a nuclear power plant requiring approximately 200,000 anchors, the difference in consumable costs between using traditional self-expanding anchors and this invention becomes extremely significant.
[0058] It should be noted that a complete anchor bolt consists of a sleeve (the expansion member in this case) and a screw, and is sold as a set. Therefore, the prices in Table 1 are calculated based on a complete anchor bolt. However, since the self-expanding expansion member of this invention can be adapted to traditional screws with tapered heads, in actual production and sales, the self-expanding expansion member of this invention can be sold separately.
[0059]
[0060] Note:
[0061] Non-structural: Connection parts that do not bear the main load-bearing function of the structure;
[0062] Structural components: Connection parts in buildings or structures that bear important structural loads;
[0063] Seismic design for structural applications takes into account the special and intense dynamic load of earthquakes, building upon the foundation of structural design.
[0064] like Figure 9 As shown, the anchor bolt is placed into the straight hole 51 of the substrate 5. When the expansion member rotates to expand the bottom, the expansion head 22 can cut the substrate 5 to form an expanded hole. At the same time, the expansion member is embedded in the expanded hole to form a locking key structure. This type of anchor bolt, which uses mechanical interlocking force as the main anchoring force, has extremely high anchoring stability. When the anchor bolt is subjected to load, due to the strong interlocking action of the mechanical locking key, the anchor bolt will not shift and can always maintain a stable anchoring state, which is unmatched by traditional expansion anchor bolts. Traditional expansion anchor bolts mainly rely on expansion force to achieve anchoring. After being subjected to large loads or long-term use, problems such as expansion force attenuation and anchor bolt loosening are prone to occur, thus affecting the anchoring effect and structural safety.
[0065] Pull-out tests were conducted on the installed expansion anchors and the anchors using the self-expanding underside expansion element of this application.
[0066] The self-expanding anchor bolt of this application provides strong anchoring force due to the mechanical engagement of the mechanical locking key, so that the bolt 4 breaks under tension. This indicates that the anchoring force between the self-expanding expansion member 1 and the base material 5 has reached a high level, and can withstand large tensile forces without overall anchor bolt failure.
[0067] Traditional expansion anchors, when pulled out, rely mainly on expansion force for anchoring. For example, with an M12×100 bolt, when the pull-out force reaches 10KN, the bolt begins to shift. When the pull-out force reaches 20KN, it will be pulled out entirely, leading to anchoring failure.
[0068] Regarding extensions:
[0069] like Figures 2 to 5 As shown, in the two-lobed expansion section 2 structure, the arc length of a single expansion piece 21 is relatively long, approaching half a circumference. Due to the greater constraint of the sleeve body, it is difficult to deform, i.e., it is difficult to achieve rotation and unfolding into a trumpet shape. Therefore, this design forms circumferentially extending notches 213 on both sides of the base 212, making the base 212 necked relative to the head 211 and the support section 3. This design does not limit the shape of the notches 213. This specification provides one shape, such as... Figure 3 As shown, the orthographic projection of notch 213 is a rectangle.
[0070] The constricted neck structure facilitates head rotation, such as... Figure 7 As shown, when the self-expanding expansion member 1 is subjected to external force and undergoes axial displacement and comes into contact with the cone head 41, the constricted structure causes the base 212 to deform preferentially. Under the combined action of axial thrust and rotational torque, the head 211 is forced to rotate outward around the constricted area. (Refer to...) Figure 8 a.
[0071] like Figure 7 As shown, the presence of the notch 213 allows the two sides of the head 211 of the expansion piece 21 to be in a free state relative to the sleeve body; that is, the two wings of the head 211 can unfold freely under force, without being constrained or restricted by the sleeve body. Figure 8 As shown, under the combined action of the thrust of the cone 41 and the reaction force of the substrate 5, the two wings of the head 211 deform outward. As the deformation proceeds, the radius of curvature gradually increases, from... Figure 8 In step b, the designation 211' changes to designation 211, eventually forming a trumpet-shaped expanded base structure. At the same time, the curvature of the head 211 gradually decreases to perfectly match the outer circumferential curvature of the cone head 41, thereby achieving a tight fit and ensuring the stability and reliability of the expanded base effect.
[0072] It can also be understood as, for example Figure 6 As shown, the central angle α1 of the base 212 is smaller than the central angle α2 of the head 211 (not shown in the figure), which facilitates the unfolding of the two wings and allows the expander to move towards the end face of the screw 4 when expanding the bottom hole. Figure 7 As shown, the inner diameter of the front end of the expansion segment 2 is represented by d, and the maximum outer diameter of the cone 41 is represented by D. Before the expansion plate is expanded, d < D; after the expansion plate is expanded, d = D. Before the expansion plate is expanded, the orthographic projection of the head 211 of the expansion plate 21 is rectangular; while after the expansion plate is expanded, because the deformation of the front end is greater than that of the rear end, the orthographic projection of the head is trapezoidal.
[0073] In the expansion piece 21, the arc length of its base 212 is 1 / 5 to 1 / 2 of the arc length of its head 211; the height of the base 212 is 1 / 5 to 1 / 2 of the height of the head 211. This proportional range design ensures that the expansion piece 21 has high bending strength while effectively achieving expansion and hole enlargement.
[0074] Comparing this invention with the sleeve of a traditional expansion anchor bolt makes the advantages of this design more clearly apparent.
[0075] Traditional expansion bolt sleeves have at least three expansion tabs 21, and typically four. Because the arc length of a single expansion tab 21 is short, less than a quarter of a circle's circumference, its enclosure degree around the cone head 41 is relatively small. During expansion, the arc length of this short expansion tab 21 remains essentially unchanged, and need not change; a certain degree of expansion is achieved simply by the expansion tab 21 rotating outward. However, this invention employs a two-part design, resulting in a higher enclosure degree around the cone head 41. For details of the expansion process, refer to [reference needed]. Figure 9 During the expansion process, if the curvature of the head 211 of the expansion piece 21 does not change, it will be subject to greater spatial restriction due to its high degree of enclosure. Figure 8 It is difficult to further expand and widen the base, which cannot meet the requirements for effective anchoring and stability in actual engineering. This well explains the necessity of the aforementioned notch 213 and necking.
[0076] There are many molding schemes for the expanding blade 22. The method adopted in this application is: to cut a groove 214 in the middle position of the head 211 of the expanding piece 21, such as... Figure 3 As shown, the expanding head 22 is then welded into the slot 214. The front end of the expanding head 22 must protrude beyond the front end of the expanding piece 21 to achieve cutting of the substrate 5. Alternatively, the expanding head 22 can be welded integrally to the head 211 of the expanding piece 21, etc., which will not be elaborated further in this case. The expanding head 22 can be made of any material capable of cutting the substrate 5, such as cemented carbide, diamond, etc. Different materials of the expanding head 22 are suitable for different types of substrates 5 and expanding requirements.
[0077] The self-expanding bottom expansion member 1 of this utility model is cut and formed from a seamless steel pipe, as shown in the reference. Figures 3 to 5 It can also be formed by pressing steel plates, see reference. Figure 10 .
[0078] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention and are mainly used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.
[0079] Furthermore, the directions such as front, back, left, and right mentioned in this embodiment are only for reference and do not represent the actual directions in use. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0080] The above description is only a preferred embodiment of this utility model and is not intended to limit the design of this case. All equivalent changes made based on the key design of this case shall fall within the protection scope of this case.
Claims
1. A self- expanding, flared stent, characterized by: The self-expanding expansion component has a cylindrical structure and is used in conjunction with a screw with a conical head; The front section of the self-expanding expansion member is the expansion section, and the rear section is the support section; The expansion section includes two arc-shaped expansion plates, and the head of the expansion plate is equipped with an expansion blade for cutting into the substrate; The base of the expansion piece connects its head and support section, and circumferentially extending notches are formed on both sides of the base, making the base appear constricted relative to the head and support section. When the expansion plate is subjected to external force and moves axially on the cone head, its base deforms, causing the head to rotate outward around the constricted neck. At the same time, the two wings of the head deform outward, gradually increasing the curvature of the head to match the curvature of the outer circumference of the cone head.
2. The self-expanding stent of claim 1, wherein: The self-expanding expansion member has an axisymmetric structure.
3. The self-expanding stent of claim 1, wherein: In the expansion piece, the arc length of the base is 1 / 5 to 1 / 2 of the arc length of the head.
4. The self-expanding stent of claim 1, wherein: In the expansion piece, the height of the base is 1 / 5 to 1 / 2 of the height of the head.
5. The self-expanding stent of claim 1, wherein: The inner diameter of the front end of the expansion section is d, and the maximum outer diameter of the cone is D. Before the expansion plate expands its bottom, d < D; after the expansion plate expands its bottom, d = D.
6. The self-expanding stent of claim 1, wherein: Before the expansion sheet is expanded, the orthographic projection of the expansion sheet head is rectangular, and after the expansion sheet is expanded, it becomes trapezoidal.
7. The self-expanding stent of claim 1, wherein: The orthographic projection of the notch is a rectangle.
8. The self-expanding stent of claim 1, wherein: On the expansion section, the circumferential gap between the heads of the two expansion plates is 0~5mm.
9. The self-expanding stent of claim 1, wherein: The wall thickness δ of the expansion piece is 2~5mm.
10. The self-expanding expansion member as described in claim 1, characterized in that: The underreaming tool is made of cemented carbide or diamond.