A low-stress anchoring device for carbon fiber cable-stayed cables and a non-invasive installation method thereof

Abstract

This invention relates to the field of bridge anchorage structural components, specifically to a low-stress anchorage device for carbon fiber stay cables and its non-destructive installation method. The device includes an anchor plate, an anchoring assembly, and a cable body inserted within the anchor plate. The anchoring assembly includes a limiting cover, a disc rotating within the limiting cover, several sets of cable clamps disposed on the outer wall of the disc, an anchor plate disposed on one side of the limiting cover, a limiting rod disposed between the anchor plate and the disc, and a second spring sleeved on the outside of the limiting rod. This invention integrates all the clamps of the cable clamps onto the same disc. When the limiting cover is tightened, all clamps are simultaneously inserted into the conical hole, achieving simultaneous anchoring of multiple cables. By using the elastic force of the second spring to maintain a gap between the clamps and the conical hole before cable insertion, the clamps are in an open state and do not contact the cable body when the cable passes through, thus providing protection.

Description

Technical Field

[0001] This invention relates to the field of bridge anchorage structural components, and more specifically, to a low-stress anchorage device for carbon fiber stay cables and its non-destructive installation method. Background Technology

[0002] Carbon fiber reinforced polymer (CFRP) is gradually replacing traditional steel as the ideal material for cables of long-span cable-stayed bridges due to its excellent properties such as lightweight, high strength, corrosion resistance, and fatigue resistance.

[0003] Patent application CN202520396898.2 discloses a cable-stayed bridge anchoring device, including an anchor assembly and a clamp assembly. The anchor assembly consists of an anchor body, a steel strand hole, an annular seat, a mating hole, and a threaded hole. By setting a limiting component, the clamp assembly and the anchor assembly can be installed in a limited position, thereby enabling the synchronous installation of the anchor assembly, multiple clamp assemblies, and the steel strand, further improving the work efficiency of steel strand anchoring installation.

[0004] However, carbon fiber materials possess characteristics such as anisotropy, low shear strength, and sensitivity to transverse stress and notch effects, which limit the direct application of traditional steel cable clamp-type anchoring devices to carbon fiber cables. Studies have shown that during the anchoring process, the wedging effect of the clamps can easily generate excessive radial shear stress on the surface of the carbon fiber reinforcement. Simultaneously, due to the light weight and low damping of carbon fiber cables, they are more prone to wind-induced vibrations than traditional steel cables, and long-term vibration can lead to fretting wear and fatigue damage in the anchoring zone.

[0005] In view of this, this application proposes a low-stress anchoring device for carbon fiber stay cables and a non-destructive installation method thereof. Summary of the Invention

[0006] The purpose of this invention is to provide a low-stress anchoring device for carbon fiber cable stays and its non-destructive installation method. By unscrewing the threaded limit rod, the second spring is further compressed, and the spring force is used to increase the frictional force on the contact surface between the disc and the limit cover. After anchoring is completed, continuous frictional damping is formed to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A low-stress anchoring device for carbon fiber cable stays includes an anchor plate, an anchoring assembly, and cable bodies passing through the anchor plate. The anchoring assembly includes a limiting cover, a disc rotating within the limiting cover, several sets of cable clamps disposed on the outer wall of the disc, an anchor plate disposed on one side of the limiting cover, a limiting rod disposed between the anchor plate and the disc, and a second spring sleeved on the outside of the limiting rod. The limiting cover is threadedly connected to the anchor plate, and several tapered holes are formed through the anchor plate for several cable bodies to pass through. When the limit cover is tightened, the drive disc and several cable clamps move toward the anchor plate, and the cable clamps are inserted into several conical holes to clamp several cable bodies. The elastic force of the second spring maintains a gap between the cable clamp and the anchor plate before cable insertion to accommodate the cable body; the limiting rod is threaded inside the anchor plate, and the compression of the second spring is adjusted by unscrewing the limiting rod to increase the friction between the disc and the limiting cover.

[0008] In the technical solution of the present invention, the anchor plate includes a stress-dispersing base, a limiting ring welded and fixed to the outer wall of the stress-dispersing base, and a sleeve. The limiting ring is disposed at one end of the anchor plate near the anchoring assembly, and the sleeve is disposed on the outside of the limiting ring and extends outward. The outer wall of the sleeve is provided with external threads.

[0009] In the technical solution of the present invention, the stress dispersion base is a disc-shaped structure used to disperse and transfer the anchoring force of the cable body to the bridge structure. The limiting ring is provided with a plurality of positioning notches, and the outer wall of the anchor plate is provided with positioning pins that are adapted to the positioning notches. The anchor plate achieves circumferential positioning by engaging the positioning pins with the positioning notches.

[0010] In the technical solution of the present invention, the limiting cover is threaded to the outside of the sleeve, and a plurality of circumferentially distributed insertion holes for use with torque wrenches are provided on the outer wall of the limiting cover. A ring plate is fixedly connected to the inner top surface of the limiting cover by bolts. There is a gap between the limiting cover and the ring plate for placing a disc. When the limiting cover is tightened, it pushes the disc to move toward the anchor plate.

[0011] In the technical solution of the present invention, the disc is provided with a plurality of grooves for placing steel cable clamping parts, and the disc is provided with a circular hole through the groove wall for the steel cable to pass through.

[0012] In the technical solution of the present invention, the steel cable clamping member includes two symmetrically arranged clamping plates and a slider integrally formed on the tail of the clamping plates, and the slider is slidably disposed in the groove.

[0013] In the technical solution of the present invention, the steel cable clamping member further includes a slide rod and a first spring. The slide rod is disposed in the slide groove and passes through the slider. The first spring is sleeved on the outside of the slide rod and its two ends abut against the slider and the groove wall of the slide groove, respectively.

[0014] In the technical solution of the present invention, a plurality of conical holes are provided through the inside of the anchor plate, and the conical holes are provided with a flared opening on the side facing the anchor plate. A receiving hole for placing the limiting rod and the second spring is provided on the top surface of the anchor plate, and a threaded groove is provided at the bottom end of the hole wall of the receiving hole.

[0015] In the technical solution of the present invention, there are two limiting rods, which are symmetrically inserted into the disc. The bottom end of the limiting rod is provided with a screw and its bottom end is threaded into the threaded groove. When the limiting rod is screwed out, the bottom screw further compresses the second spring. The elastic force of the second spring is transmitted to the limiting cover through the disc, increasing the friction between the disc and the limiting cover.

[0016] On the other hand, the present invention also provides a non-destructive installation method for a low-stress anchoring device for carbon fiber stay cables, comprising the following steps: S1. Install the anchoring assembly on the anchor plate, so that the cable body passes through the tapered hole of the anchor plate and the cable clamp; S2. Tighten the limiting cover, drive the disc and steel cable clamp to move towards the anchor plate, insert the steel cable clamp into the conical hole to clamp the cable body, and complete the anchoring; S3. Unscrew the limiting rod and adjust the compression of the second spring to increase the friction between the disc and the limiting cover.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. The low-stress anchoring device for carbon fiber cable stays and its non-destructive installation method maintain a gap between the clamp and the conical hole by using the elastic force of the second spring before cable insertion. When the cable passes through, the clamp is in an open state and does not contact the cable body, which plays a protective role and avoids frictional damage to the surface of the carbon fiber cable body caused by the inner wall threads of the clamp during cable insertion.

[0018] 2. The low-stress anchoring device for carbon fiber cable stays and its non-destructive installation method further compress the second spring by unscrewing the threaded limit rod. The spring force increases the friction between the contact surface between the disc and the limit cover, forming continuous frictional damping after anchoring, effectively resisting micro-vibration and loosening of the anchoring area under dynamic loads such as wind vibration.

[0019] 3. The low-stress anchoring device for carbon fiber cable stays and its non-destructive installation method integrate all the clamping pieces of the cable clamping components onto the same disc. When the limiting cover is tightened, all the clamping pieces are simultaneously inserted into the conical hole, thus achieving simultaneous anchoring of multiple cables. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure assembly of the present invention; Figure 2 This is a partial structural breakdown diagram of the present invention; Figure 3 This is a schematic diagram of the anchor plate in this invention; Figure 4 This is a cross-sectional schematic diagram of the anchoring assembly in this invention; Figure 5 This is one of the structural schematic diagrams of the limiting cover in this invention; Figure 6 This is a cross-sectional schematic diagram of the limiting cover in this invention; Figure 7 This is one of the partial structural schematic diagrams of the anchoring assembly in this invention; Figure 8 This is a schematic diagram of the structure of the disk in this invention; Figure 9 This is a schematic diagram of the steel cable clamping component in this invention; Figure 10 This is a schematic diagram of the anchor plate in this invention; Figure 11 This is a cross-sectional schematic diagram of the anchor plate in this invention; Figure 12 This is a second schematic diagram of a portion of the anchoring assembly in this invention; Explanation of reference numerals in the attached figures: 100. Anchor plate; 110. Stress dispersion base; 120. Limiting ring; 121. Positioning notch; 130. Sleeve; 200, Anchoring assembly; 210, Limiting cover; 211, Insertion hole; 220, Ring plate; 230, Disc; 231, Slide groove; 232, Circular hole; 240, Cable clamping component; 241, Clamping piece; 242, Sliding block; 243, Slide rod; 244, First spring; 250, Anchor plate; 251, Tapered hole; 252, Positioning pin; 253, Receiving hole; 254, Threaded groove; 260, Limiting rod; 270, Second spring; 300. Cable body. Detailed Implementation

[0021] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0022] Please see Figures 1-2 As shown, this embodiment provides a technical solution: A low-stress anchoring device for carbon fiber cable-stayed bridges includes an anchor plate 100, an anchoring assembly 200, and a cable body 300 inserted within the anchor plate 100. The anchor plate 100 serves as an anchoring base pre-embedded in the bridge structure. The cable body 300 comprises an internal CFRP carbon fiber cable and an HDPE sheath covering the cable body. The CFRP carbon fiber cable is composed of multiple 7mm diameter carbon fiber tendons arranged in a tight hexagonal pattern, with polyester winding tape wrapped around the tendon bundle to form an integral bundle. The HDPE sheath is extruded entirely over the polyester winding tape, and its surface has spiral convex lines to suppress wind and rain vibration. The CFRP carbon fiber cable has a tensile strength ≥2400MPa and an elastic modulus ≥175GPa, and the self-weight of the cable body 300 is only one-quarter that of a steel cable with the same load-bearing capacity.

[0023] like Figure 3 As shown, the anchor plate 100 includes a stress-dispersing base 110, a limiting ring 120 welded and fixed to the outer wall of the stress-dispersing base 110, and a sleeve 130. The limiting ring 120 is an annular protrusion structure with several positioning notches 121, and is located at one end of the anchor plate 100 near the anchoring assembly 200. The sleeve 130 is located on the outside of the limiting ring 120 and extends outward, with external threads on its outer wall. The stress-dispersing base 110 is a disc-shaped structure used to disperse and transfer the anchoring force of the cable body 300 to the bridge structure, avoiding stress concentration that could cause localized damage to the bridge concrete.

[0024] Please see Figures 4-12 As shown, in this embodiment, the anchoring assembly 200 includes a limiting cover 210, an annular plate 220 fixedly connected to the inner top surface of the limiting cover 210 by bolts, a disc 230 rotating inside the limiting cover 210, several sets of steel cable clamping members 240 disposed on the outer wall of the disc 230, an anchor plate 250 disposed on one side of the limiting cover 210, a limiting rod 260 disposed between the anchor plate 250 and the disc 230, and a second spring 270 sleeved on the outside of the limiting rod 260. The limiting cover 210 is threadedly connected to the anchor plate 100.

[0025] Furthermore, such as Figures 4-6 As shown, the limiting cover 210 is threaded to the outside of the sleeve 130. The outer wall of the limiting cover 210 has several circumferentially distributed insertion holes 211 for use with torque wrenches. There is a gap between the limiting cover 210 and the ring plate 220 for placing the disc 230. When the limiting cover 210 is tightened, it pushes the disc 230 to move towards the anchor plate 250. The limiting cover 210 is a hollow cover structure with internal threads on its inner wall.

[0026] Furthermore, such as Figures 7-9As shown, the disc 230 is a circular plate structure, rotatably mounted inside the limiting cover 210. The disc 230 has several grooves 231 for placing cable clamping components 240. Circular holes 232 are formed through the groove walls of the disc 230 for the cable to pass through. Each set of cable clamping components 240 corresponds to a cable in the cable body 300. Each cable clamping component 240 includes two symmetrically arranged clamping plates 241 and a slider 242 integrally formed at the tail of the clamping plates 241. The slider 242 is slidably disposed within the groove 231. The cable clamping component 240 also includes a sliding rod 243 and a first spring 244. The sliding rod 243 is disposed within the groove 231 and passes through the slider 242. The first spring 244 is sleeved on the outside of the sliding rod 243, with its two ends abutting against the slider 242 and the groove walls of the groove 231, respectively.

[0027] Furthermore, the clamp 241 is an anchor clamp in the prior art, and its inner wall is provided with threads for clamping the steel cable. The elastic force of the first spring 244 keeps the clamp 241 in an open state so that the steel cable can pass through. It should be noted that, as Figure 9 As shown, the state of the cable clamp 240 at this time is the state after it is inserted into the anchor plate 250, and the first spring 244 shown in the figure is in a stretched state.

[0028] Please see Figures 10-12 As shown, in this embodiment, the anchor plate 250 is a circular plate structure, disposed on the side of the limiting cover 210 near the anchor plate 100. Figure 11 As shown, the anchor plate 250 has several conical holes 251 through which several cable bodies 300 pass. The diameter of the conical holes 251 gradually narrows from one end near the cable clamp 240 to the other end, forming a wedge-shaped inner wall. It should be noted that the cone angle of the conical hole is α. The outer wall of the clamp 241 is a conical surface with a cone angle of β, and β > α. Specifically, β is about 0.33°-0.5° more than α. When the limiting cover 210 is tightened, the disc 230 pushes the clamp 241 to move towards the smaller end of the conical hole 251. Since the outer cone angle β of the clamping piece 241 is greater than the cone angle α of the conical hole 251, the clamping piece 241 is subjected to radial compression from the inner wall of the conical hole 251 during its entry into the conical hole 251, forcing each fan ring to contract radially inward, thereby clamping the carbon fiber cable body inside the cable body 300 inserted in the clamping piece 241; as the tightening degree of the limiting cover 210 increases, the depth of the clamping piece 241 wedged into the conical hole 251 increases, the radial compression force increases, and the clamping force of the clamping piece 241 on the cable body 300 also increases, forming a reliable wedging anchor.

[0029] Furthermore, the tapered hole 251 has a flared opening at one end near the anchor plate 100. The flared opening allows the steel cable to have a larger guide angle when it enters the tapered hole 251, making it easier for the steel cable to pass through smoothly. At the same time, it reduces the friction and scratching between the steel cable and the entrance edge of the tapered hole 251, further reducing the risk of damage to the carbon fiber cable.

[0030] Furthermore, the outer wall of the anchor plate 250 is provided with a positioning pin 252 that matches the positioning notch 121. The anchor plate 250 achieves circumferential positioning by engaging the positioning pin 252 with the positioning notch 121. Several conical holes 251 are provided through the interior of the anchor plate 250. The side of the conical holes 251 facing the anchor plate 100 has a flared opening. The top surface of the anchor plate 250 has a receiving hole 253 for placing the limiting rod 260 and the second spring 270. The bottom end of the hole wall of the receiving hole 253 has a threaded groove 254. Two limiting rods 260 are symmetrically inserted into the disc 230. The top of the limiting rod 260 extends from the back of the disc 230, allowing the operator to screw it from the outside. The bottom of the limiting rod 260 is provided with a screw, and its bottom end is threaded into the threaded groove 254. When the limiting rod 260 is screwed out, the bottom screw further compresses the second spring 270. The elastic force of the second spring 270 is transmitted to the limiting cover 210 through the disc 230, increasing the friction between the disc 230 and the limiting cover 210.

[0031] Furthermore, when the limiting cover 210 is tightened, the drive disc 230 and several cable clamping parts 240 move toward the anchor plate 250. The cable clamping parts 240 are inserted into several conical holes 251 to clamp several cable bodies 300. The elastic force of the second spring 270 keeps the gap between the cable clamping parts 240 and the anchor plate 250 before the cable is threaded to fit the cable body 300. The limiting rod 260 is threaded inside the anchor plate 250. By unscrewing the limiting rod 260, the compression of the second spring 270 is adjusted to increase the friction between the disc 230 and the limiting cover 210. Specifically, after anchoring is completed, the limiting rod 260 is unscrewed from the back of the anchor plate 250. When the limiting rod 260 is unscrewed, its bottom screw is unscrewed in the threaded groove 254 of the receiving hole 253, further compressing the second spring 270. After the second spring 270 is further compressed, its elastic force increases, and a larger axial force is transmitted to the contact surface of the limiting cover 210 through the disc 230, increasing the friction between the disc 230 and the limiting cover 210. This increase in friction is used to resist the micro-vibration of the cable under dynamic loads such as wind vibration, and to prevent the relative rotation or loosening of the disc 230 and the clamp 241. At the same time, the two limiting rods 260 pass through the disc 230, restricting the rotation of the disc 230 in the circumferential direction, further ensuring the fixation of the disc 230.

[0032] The present invention provides a non-destructive installation method for a low-stress anchoring device for carbon fiber cable stays, comprising the following steps: S1. Install the anchoring assembly 200 on the anchor plate 100, so that the cable body 300 passes through the tapered hole 251 of the anchor plate 250 and the cable clamp 240. Specifically, the anchoring assembly 200 is pre-assembled. Under the elastic force of the second spring 270, the disc 230 and the cable clamp 240 are pushed away from the anchor plate 250, and a gap is maintained between the clamp 241 and the conical hole 251. The pre-assembled anchoring assembly 200 is installed on the anchor plate 100, and the positioning pin 252 of the anchor plate 250 is inserted into the positioning notch 121 of the limiting ring 120 to achieve circumferential positioning of the anchor plate 250. The cable body 300 passes through the insertion hole 211 of the limiting cover 210 and then passes through the conical hole 251 of the anchor plate 250 and the clamp 241 of the cable clamp 240 in sequence. Since the clamp 241 is in an open state and there is a gap between it and the conical hole 251, the threads on the inner wall of the clamp 241 do not contact the cable body when the cable body 300 passes through, and the cable can pass through without obstruction without causing friction damage to the surface of the carbon fiber cable. S2. Tighten the limiting cover 210, drive the disc 230 and the cable clamp 240 to move towards the anchor plate 250, insert the cable clamp 240 into the conical hole 251 to clamp the cable body 300, and complete the anchoring; after the cable body 300 is fully inserted, tighten the limiting cover 210; the internal thread of the limiting cover 210 is engaged with the external thread of the sleeve 130, and when the limiting cover 210 is tightened, it pushes the disc 230 and the cable clamp 240 to move towards the anchor plate 250 against the elastic force of the second spring 270 through the ring plate 220; The clamping plate 241 is gradually inserted into the conical hole 251. Under the wedging action of the conical hole 251, the clamping plate 241 closes and clamps the cable body 300, completing the anchoring. The tightening process of the limiting cover 210 is carried out by inserting a torque wrench into the insertion hole 211 to control the tightening torque. According to the design tension of the cable, the contact area between the clamping plate 241 and the conical hole 251 and the coefficient of friction, the target torque value is pre-calculated and set. During the tightening process, when the torque wrench reaches the preset torque value, a prompt is issued and the operator stops tightening to ensure that the wedging force of the clamping plate 241 is moderate, which can reliably clamp the cable without damaging the carbon fiber cable body due to excessive radial shear stress. S3. Unscrew the limiting rod 260 and adjust the compression of the second spring 270 to increase the friction between the disc 230 and the limiting cover 210.

[0033] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the specification and its equivalents.

Claims

1. A low-stress anchoring device for carbon fiber cable stays, comprising an anchor plate, an anchoring assembly, and a cable body passing through the anchor plate, characterized in that: The anchoring assembly includes a limiting cover, a disc rotating inside the limiting cover, several sets of steel cable clamps disposed on the outer wall of the disc, an anchor plate disposed on one side of the limiting cover, a limiting rod disposed between the anchor plate and the disc, and a second spring sleeved on the outside of the limiting rod; the limiting cover is threadedly connected to the anchor plate, and several conical holes are opened through the anchor plate for several cable bodies to pass through; When tightening the limit cover, the drive disc and several steel cable clamping parts are inserted into several conical holes to clamp several cable bodies; The elastic force of the second spring maintains a gap between the cable clamp and the anchor plate before cable insertion to accommodate the cable body; the limiting rod is threaded inside the anchor plate, and the compression of the second spring is adjusted by unscrewing the limiting rod to increase the friction between the disc and the limiting cover.

2. The low-stress anchoring device for carbon fiber cable stays according to claim 1, characterized in that: The anchor plate includes a stress-dispersing base, a limiting ring welded and fixed to the outer wall of the stress-dispersing base, and a sleeve. The limiting ring is located at one end of the anchor plate near the anchoring assembly, and the sleeve is located outside the limiting ring and extends outward. The outer wall of the sleeve is provided with external threads.

3. The low-stress anchoring device for carbon fiber cable stays according to claim 2, characterized in that: The stress-dispersing base is a disc-shaped structure used to disperse and transfer the anchoring force of the cable body to the bridge structure. The limiting ring has several positioning notches, and the outer wall of the anchor plate is provided with positioning pins that are adapted to the positioning notches. The anchor plate achieves circumferential positioning by engaging the positioning pins with the positioning notches.

4. The low-stress anchoring device for carbon fiber cable stays according to claim 3, characterized in that: The limiting cover is threaded to the outside of the sleeve. Several circumferentially distributed insertion holes for use with torque wrenches are provided on the outer wall of the limiting cover. A ring plate is fixedly connected to the inner top surface of the limiting cover by bolts. There is a gap between the limiting cover and the ring plate for placing a disc. When the limiting cover is tightened, it pushes the disc to move towards the anchor plate.

5. The low-stress anchoring device for carbon fiber cable stays according to claim 4, characterized in that: The disc has several grooves for placing steel cable clamping parts, and the disc has circular holes through the groove walls for the steel cables to pass through.

6. The low-stress anchoring device for carbon fiber cable stays according to claim 5, characterized in that: The cable clamping component includes two symmetrically arranged clamping plates and a slider integrally formed at the tail of the clamping plates, wherein the slider is slidably disposed in a groove.

7. The low-stress anchoring device for carbon fiber cable stays according to claim 6, characterized in that: The cable clamping component also includes a slide rod and a first spring. The slide rod is disposed in the slide groove and passes through the slider. The first spring is sleeved on the outside of the slide rod and its two ends abut against the slider and the groove wall of the slide groove, respectively.

8. The low-stress anchoring device for carbon fiber cable stays according to claim 7, characterized in that: The anchor plate has several conical holes running through it. The conical holes have flared openings on the side facing the anchor plate. The top surface of the anchor plate has a receiving hole for placing the limiting rod and the second spring. The bottom end of the receiving hole wall has a threaded groove.

9. The low-stress anchoring device for carbon fiber cable stays according to claim 8, characterized in that: The limiting rod consists of two rods, symmetrically inserted into the disc. The bottom end of each limiting rod is provided with a screw, and its bottom end is threaded into a threaded groove. When the limiting rod is screwed out, the bottom screw further compresses the second spring. The elastic force of the second spring is transmitted to the limiting cover through the disc, increasing the friction between the disc and the limiting cover.

10. A non-destructive installation method for a low-stress anchoring device for carbon fiber stay cables, using the low-stress anchoring device for carbon fiber stay cables as described in claim 9, characterized in that... Includes the following steps: S1. Install the anchoring assembly on the anchor plate, so that the cable body passes through the tapered hole of the anchor plate and the cable clamp; S2. Tighten the limiting cover, drive the disc and steel cable clamp to move towards the anchor plate, insert the steel cable clamp into the conical hole to clamp the cable body, and complete the anchoring; S3. Unscrew the limiting rod and adjust the compression of the second spring to increase the friction between the disc and the limiting cover.

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