Tunnel multi-stage rotary braking trolley and construction method thereof

Abstract

The application discloses a tunnel multi-stage rotary braking trolley and a construction method thereof. The trolley comprises a trolley main body structure (100), a first rotary braking mechanism (200) arranged at the bottom of the trolley main body structure (100), a second rotary braking mechanism (300) arranged at the middle of the trolley main body structure (100) and a third rotary braking mechanism (400) arranged at the top of the trolley main body structure (100). The first rotary braking mechanism (200) comprises a first braking displacement sliding groove (201), a first end head rotary device (202), a first telescopic rod (204) and a first clamping unit (203), a rotary braking device (206) arranged in the first braking displacement sliding groove (201), and the first telescopic rod (204) is connected with the rotary braking device (206) through a first rotary interface (205). The trolley not only realizes automatic, rapid and accurate positioning construction of a tunnel steel frame, but also greatly improves construction efficiency and greatly reduces construction safety risks.

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction technology, and more specifically, relates to a tunnel multi-stage rotating braking trolley and its construction method. Background Technology

[0002] Subway tunnel construction trolleys are specialized equipment used in the secondary lining process during tunnel construction, specifically for lining the inner walls of tunnels. Currently, due to differences in construction environment and requirements, the cross-sectional profiles of subway tunnels in my country often vary. Therefore, all components of the lining trolley need to be redesigned and processed according to these different profiles, significantly increasing both the design and processing cycles.

[0003] To address the aforementioned issues, patent document CN 111997655A discloses a construction method for a rotatable concrete lining formwork trolley capable of rotating within a tunnel. The method involves installing a foldable concrete lining formwork trolley on a straight track; driving the straight-line travel system on the foldable concrete lining formwork trolley to move it to the tunnel section to be rotated; folding the foldable concrete lining formwork trolley; installing a support device on the concrete lining formwork trolley to support the folded trolley until it is off the straight track; installing an arc-shaped guide rail; installing at least two rotating wheels on each of the two lower longitudinal beams of the folded concrete lining formwork trolley, with adjacent rotating wheels spaced apart; retracting the support device so that the rotating wheels fall onto the arc-shaped track; and installing a drive device to move the rotating wheels, causing the folded concrete lining formwork trolley to move along the arc-shaped track to the direction of construction. In addition, the cross-section of subway tunnels is relatively small. Existing tunnel lining trolleys have small clearance and small demolding capacity. Even small loaders cannot pass through the lining trolleys during tunnel construction. The secondary lining steel frame structure is generally constructed by manual handling and assembly. Furthermore, operations such as drilling blast holes are mostly carried out manually. Due to the bulky steel frame structure, manual handling and assembly in the confined space of the tunnel not only results in low precision and efficiency in secondary lining and blast hole drilling, but also causes great inconvenience to tunnel construction, prolongs the tunnel construction cycle, and poses many safety hazards, which can easily lead to construction accidents and affect construction quality and efficiency. Summary of the Invention

[0004] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a tunnel multi-stage rotary braking trolley and its construction method. The first telescopic rod is lowered to a certain height and extended to a suitable length. A first clamping unit mounted on the first rotary braking mechanism precisely clamps and positions one end of the steel frame. A first end-rotating device drives the trolley to rotate around a first braking displacement groove at a certain angle until the steel frame moves to the matching position of the tunnel's primary lining profile. Then, the second rotary braking mechanism drives the steel frame to rise to the third rotary braking mechanism, and the third rotary braking mechanism continues to raise it to the tunnel's primary lining profile position. This cycle repeats, rotating and driving the secondary lining steel frame to the matching position of the tunnel's primary lining profile, achieving automatic and precise alignment, welding, and forming of multiple sections of the secondary lining steel frame profile. This not only realizes automatic, rapid, and precise positioning construction of the tunnel's secondary lining steel frame but also greatly improves construction efficiency. Through mechanized automated trolley construction, the labor intensity of workers is significantly reduced, and construction safety risks are lowered.

[0005] To achieve the above objectives, according to one aspect of the present invention, a tunnel multi-stage rotary braking trolley is provided, comprising a trolley main structure (100), a first rotary braking mechanism (200) disposed at the bottom of the trolley main structure (100), a second rotary braking mechanism (300) disposed in the middle of the trolley main structure (100), and a third rotary braking mechanism (400) disposed at the top of the trolley main structure (100); wherein,

[0006] The first rotary braking mechanism (200) includes a first braking displacement groove (201) disposed on one side of the bottom of the trolley main body structure (100), a first end rotating device (202) disposed on the first braking displacement groove (201), a first telescopic rod (204) slidably connected to the first braking displacement groove (201), and a first clamping unit (203) disposed at one end of the first telescopic rod (204), and a rotary braking device (206) disposed in the first braking displacement groove (201). The first telescopic rod (204) is connected to the rotary braking device (206) through a first rotating interface (205).

[0007] After the first telescopic rod (204) is lowered to a certain height and extended to a suitable length, the first clamping unit (203) is used to clamp and accurately position one end of the steel frame. The first end rotating device (202) drives the rod to rotate around the first braking displacement groove (201) by a certain angle until it moves to the tunnel profile matching position. Then, the second rotating braking mechanism (300) drives the construction object to rise to the third rotating braking mechanism (400), and the third rotating braking mechanism (400) continues to rise to the tunnel masonry profile position. The construction object is rotated and driven to rise to the tunnel profile matching position in a cyclical manner, so as to realize the automatic and accurate positioning of the profile of multiple construction objects and the construction is completed.

[0008] Furthermore, the first clamping unit (203) includes two fastening structures. The first part includes a first fixed main plate (2031) connected to one end of the first telescopic rod (204). The first fixed main plate (2031) is provided with at least one first fixed plate slide groove (2032) and a first telescopic clip (2033) matched with the first fixed plate slide groove (2032).

[0009] Furthermore, the first part includes two side plates (2034) that are vertically connected to the first fixed motherboard (2031) and connected via the first telescopic clip (2033).

[0010] Furthermore, the second part of the first clamping unit (203) includes a first fixed small motherboard (2037), a first fixed slide groove and a telescopic clip (2036) disposed on the first fixed small motherboard (2037).

[0011] Furthermore, the second part includes two small clamping plates (2035) vertically disposed on both sides of the first fixed small main board (2037), and a first telescopic fixing device (2038) disposed on the first fixed small main board (2037).

[0012] Furthermore, the second rotary braking mechanism (300) includes a second braking displacement groove (301), a second telescopic rod (302) connected to the second braking displacement groove (301), and a second clamping unit (303) disposed at one end of the second telescopic rod (302).

[0013] Furthermore, the second clamping unit (303) includes a second fixing plate (3031) arranged symmetrically, a brake roller (3033) installed on the inner side of the second fixing plate connected to the second telescopic rod (302), and a regular roller (3032) provided on the second fixing plate on the other side.

[0014] Furthermore, the second clamping unit (303) includes a second telescopic fixing box (2036) respectively disposed on both sides of the second fixing plate (3031).

[0015] Furthermore, the second clamping unit (303) includes a second telescopic clip (2034) disposed on the second telescopic fixing box (2035), and a second telescopic fixing device (2035) disposed on the second telescopic fixing box (2036).

[0016] According to a second aspect of the present invention, a method for constructing a tunnel multi-stage rotating braking trolley is provided, comprising the following steps:

[0017] S100: Lower the telescopic rod of the first rotary braking mechanism and extend it to a suitable length. Rotate the first rotary braking mechanism to stabilize one end of the steel frame on the ground. Then activate the first rotary braking mechanism to make the steel frame stand up inside the tunnel excavation outline. Then use the telescopic rods at the top and middle and the second rotary braking mechanism to clamp and fix the steel frame in the middle and top.

[0018] S200: Use the second rotary braking mechanism to activate the roller brake, and use the roller to transfer the fixed steel frame to the top of the arch and connect it with the steel frames on both sides. Use the telescopic rod to adjust the distance from the tunnel excavation outline. After the steel frame on the same cross section is adjusted, the next welding work can be carried out.

[0019] S300: The working surface of the upright frame is moved by the brake slide groove installed on the trolley, and the work is carried out in a cycle.

[0020] S400: In the drilling process, the drilling jackhammer support rod is fixed inside the clamping unit of each layer. The position and direction of the drilling jackhammer are controlled by adjusting the direction of the clamping unit, the length of the telescopic rod and the brake slide.

[0021] S500: After use, the telescopic rod can be retracted and secured to the inside of the trolley frame by connecting the brake slide and the rotary brake device to prevent damage.

[0022] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0023] 1. The multi-stage rotary braking trolley of the present invention lowers the first telescopic rod to a certain height and extends it to a suitable length. Then, through the first clamping unit set on the first rotary braking mechanism, it clamps and precisely positions one end of the steel frame. The first end rotating device drives the steel frame to rotate around the first braking displacement groove at a certain angle until the steel frame moves to the matching position of the tunnel primary lining profile. Then, the second rotary braking mechanism drives the steel frame to rise to the third rotary braking mechanism, and the third rotary braking mechanism continues to rise to the tunnel primary lining profile position. The secondary lining steel frame is rotated and driven to rise to the matching position of the tunnel primary lining profile in a cyclical manner, realizing the automatic and precise alignment, welding and forming of multiple sections of secondary lining steel frame profile. This not only realizes the automatic, fast and precise positioning construction of the tunnel secondary lining steel frame, but also greatly improves the construction efficiency. Through the construction of the mechanized automated trolley, the labor intensity of workers is greatly reduced and the construction safety risks are reduced.

[0024] 2. The multi-stage rotary braking trolley of the present invention drives the first telescopic rod to rotate through the first end rotating device, thereby rotating the steel frame to a position that matches the profile of the tunnel lining. This achieves automated rotation and precise positioning of the steel frame, significantly optimizing manpower, improving work safety, increasing project progress and efficiency, and assisting in drilling and semi-automating the erection process. It also avoids falling rocks from unstable surrounding rock during erection, thus improving the accuracy and efficiency of the erection process.

[0025] 3. The multi-stage rotary braking trolley of the present invention flexibly adjusts the two side clamps to a suitable width position along the first telescopic clamp according to the size specifications of the steel frame, ensuring that the two side clamps and the first fixed main plate wrap around the end of the steel frame; then the second part is connected to the first part, and the two side small clamps are stretched to a certain range and clamped on the outside of the first fixed small main plate for secondary stabilization. The two side small clamps are tightened again by the first telescopic fixing device to achieve a stabilizing effect and ensure its stability during rotation.

[0026] 4. The multi-stage rotary braking trolley of the present invention rotates from the first rotary braking mechanism to the second rotary braking mechanism, and then fixes the second fixed plates on both sides by the second telescopic clamp. The second telescopic clamp is subjected to force by the second telescopic fixing device inside the second telescopic fixing box, thereby stabilizing the second fixed plate. Then, the steel frame is lifted and transported to the tunnel secondary lining profile position for precise positioning by the cooperation of the brake roller and ordinary roller, and is precisely docked with other steel frame structures transported by the first rotary braking mechanism to achieve welding and forming. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of a tunnel multi-stage rotary braking trolley according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the first rotary braking mechanism in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the structure of the first clamping unit in an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the second rotary braking mechanism in an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the structure of the second clamping unit in an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the structure of the second fixing plate and rollers in an embodiment of the present invention;

[0033] Figure 7 This is a schematic diagram of the structure of the second telescopic clip on the right side in an embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of the second telescopic clip structure on the left side in an embodiment of the present invention;

[0035] Figure 9 This is a flowchart of a tunnel multi-stage rotating braking trolley construction method according to an embodiment of the present invention.

[0036] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 100-main structure of the trolley, 200-first rotary braking mechanism, 201-first braking displacement groove, 202-first end rotating device, 203-first clamping unit, 2031-first fixed main board, 2032-first fixed plate groove, 2033-first telescopic clamp, 2034-side clamping plates, 2035-side small clamping plates, 2036-first fixed groove and telescopic clamp, 2037-first fixed small main board. 2038 - First telescopic fixing device; 204 - First telescopic rod; 205 - First rotating interface; 206 - Rotary braking device; 300 - Second rotary braking mechanism; 301 - Second braking displacement groove; 302 - Second telescopic rod; 303 - Second clamping unit; 3031 - Second fixing plate; 3032 - Ordinary roller; 3033 - Braking roller; 3034 - Second telescopic clamp; 3035 - Second telescopic fixing device; 2036 - Second telescopic fixing box; 400 - Third rotary braking mechanism. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0038] like Figure 1 As shown, this embodiment of the invention provides a tunnel multi-stage rotary braking trolley, which includes a trolley main structure 100. Rotary braking mechanisms can be installed at the bottom, middle, and top of the trolley at the working face. Specifically, it includes a first rotary braking mechanism 200 located at the bottom of the trolley main structure 100, a second rotary braking mechanism 300 located at the middle of the trolley main structure 100, and a third rotary braking mechanism 400 located at the top of the trolley main structure 100. The first rotary braking mechanism 200 includes a first braking displacement groove 201 located on one side of the bottom of the trolley main structure 100, a first end rotating device 202 located on the first braking displacement groove 201, a first telescopic rod 204 slidably connected to the first braking displacement groove 201, and a first clamping unit 203 located at one end of the first telescopic rod 204. After the first telescopic rod 204 is lowered to a certain height and extended to a suitable length, the first clamping unit 203 on the first rotary braking mechanism 200 clamps and precisely positions one end of the steel frame. The first end rotating device 202 drives the steel frame to rotate around the first braking displacement groove 201 at a certain angle until the steel frame moves to the matching position of the tunnel primary lining profile. Then, the second rotary braking mechanism 300 drives the steel frame to rise to the third rotary braking mechanism 400, and the third rotary braking mechanism 400 continues to rise to the tunnel primary lining profile position. This process is repeated to rotate and drive the secondary lining steel frame to the matching position of the tunnel primary lining profile, realizing the automatic and precise alignment, welding, and forming of multiple sections of the secondary lining steel frame profile. This not only achieves automatic, fast, and precise positioning construction of the tunnel secondary lining steel frame, but also greatly improves construction efficiency. Through the construction of the mechanized automated trolley, the labor intensity of workers is greatly reduced, and the construction safety risks are reduced.

[0039] like Figure 2 As shown, the first rotary braking mechanism 200 includes a rotary braking device 206 disposed in the first braking displacement groove 201. The first telescopic rod 204 is connected to the rotary braking device 206 through the first rotary interface 205. The first telescopic rod 204 can be driven to rotate by the first end rotating device 202 to rotate by a certain angle, thereby rotating the steel frame to the position that matches the profile of the tunnel primary lining, thus realizing the automated rotation and precise positioning of the steel frame.

[0040] In embodiments of the present invention, such as Figure 3 As shown, the first clamping unit 203 includes two fastening structures. The first part includes a first fixed main plate 2031 connected to one end of the first telescopic rod 204. The first fixed main plate 2031 is provided with at least one first fixed plate slide groove 2032, a first telescopic clip 2033 matched with the first fixed plate slide groove 2032, and two side clamps 2034 vertically connected to the first fixed main plate 2031 and connected through the first telescopic clip 2033. The second part includes a first fixed small main plate 2037, a first fixed slide groove and telescopic clip 2036 provided on the first fixed small main plate 2037, two side small clamps 2035 vertically provided on both sides of the first fixed small main plate 2037, and a first telescopic fixing device 2038 provided on the first fixed small main plate 2037. According to the size and specifications of the steel frame, the two side clamps 2034 are flexibly adjusted to move along the first telescopic clamp 2033 to a suitable width position to ensure that the two side clamps 2034 and the first fixed main plate 2031 wrap around the end of the steel frame; then the second part is connected with the first part, and the two side small clamps 2035 are stretched to a certain range and clamped on the outside of the first fixed small main plate 2037 for secondary stabilization. The two side small clamps 2035 are tightened again by the first telescopic fixing device 2038 to achieve a stabilizing effect and ensure stability during its rotation.

[0041] like Figures 4-8 As shown, in the embodiments of the present invention, the second rotary braking mechanism 300 and the third rotary braking mechanism 400 have similar structures, such as... Figure 4 As shown, taking the second rotary braking mechanism 300 as an example, it includes a second braking displacement groove 301, a second telescopic rod 302 connected to the second braking displacement groove 301, and a second clamping unit 303 disposed at one end of the second telescopic rod 302. Figure 5As shown, the second clamping unit 303 includes a second fixed plate 3031 symmetrically arranged, a brake roller 3033 installed on the inner side of the second fixed plate connected to the second telescopic rod 302, a regular roller 3032 on the other side of the second fixed plate, a second telescopic fixing box 2036 respectively disposed on both sides of the second fixed plate 3031, a second telescopic clip 2034 disposed on the second telescopic fixing box 2036, and a second telescopic fixing device 3035 disposed on the second telescopic fixing box 2036. After rotating from the first rotary braking mechanism 200 to the second rotary braking mechanism 300, the second fixed plates 3031 on both sides are fixed by the second telescopic clamp 2034. The second telescopic clamp 2034 is subjected to force by the second telescopic fixing device 3035 inside the second telescopic fixing box 2036, thereby stabilizing the second fixed plates 3031. Then, the steel frame is lifted and transported to the tunnel secondary lining profile position for precise positioning by the brake roller 3033 and the ordinary roller 3032. It is then precisely docked with other steel frame structures transported by the first rotary braking mechanism 200 to achieve welding and forming.

[0042] like Figure 9 As shown, in another embodiment of the present invention, a method for constructing a multi-stage rotating braking platform for secondary tunnel lining is provided, comprising the following steps:

[0043] Step 1: Lower the telescopic rod of the first rotary braking mechanism and extend it to a suitable length. Rotate the first rotary braking mechanism to stabilize one end of the steel frame on the ground. Then activate the first rotary braking mechanism 200 to make the steel frame stand up inside the tunnel excavation outline. Then use the telescopic rods at the top and middle and the second rotary braking mechanism to clamp and fix the steel frame in the middle and top.

[0044] Step 2: If the steel frame is segmented, use the second rotary braking mechanism to activate the roller brake, and use the roller to transfer the fixed steel frame to the top of the arch and connect it with the steel frames on both sides. Use the telescopic rod to adjust the distance from the tunnel excavation outline. After the steel frame on the same cross section is adjusted, the next welding work can be carried out.

[0045] Step 3: Move the working surface of the upright frame through the brake slide groove installed on the trolley, and repeat the operation in this cycle.

[0046] Step 4: In the drilling process, the drilling jackhammer support rod can be firmly fixed inside the clamping unit of each layer. The position and direction of the drilling jackhammer can be controlled by adjusting the direction of the clamping unit, the length of the telescopic rod and the brake slide.

[0047] Step 5: After use, the telescopic rod can be retracted and secured to the inside of the trolley frame by connecting the brake slide and the rotary brake device to prevent damage.

[0048] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A tunnel multi-stage rotary braking trolley comprising a trolley main structure, characterized by, Further comprising a first rotation braking mechanism arranged at the bottom of the trolley body structure, a second rotation braking mechanism arranged at the middle of the trolley body structure, and a third rotation braking mechanism arranged at the top of the trolley body structure; wherein, The first rotation braking mechanism comprises a first braking displacement sliding groove arranged at one side of the bottom of the trolley body structure, a first end head rotation device arranged on the first braking displacement sliding groove, a first telescopic rod in sliding connection with the first braking displacement sliding groove, and a first clamping unit arranged at one end of the first telescopic rod, a rotation braking device arranged in the first braking displacement sliding groove, the first telescopic rod is connected with the rotation braking device through a first rotation interface, the first telescopic rod is driven to rotate by a certain angle through the first end head rotation device, the steel frame is rotated to a position matched with the profile of the tunnel lining, the automatic rotation of the steel frame is realized, the precise positioning is realized, the drilling process is assisted, the semi-automatic vertical frame process is realized, and the falling rocks from the unstable surrounding rock above during the vertical frame process can be avoided; The first clamping unit comprises two part buckling structures, a first part comprises a first fixed main plate connected with one end of the first telescopic rod, at least one first fixed plate sliding groove is arranged in the first fixed main plate, a first telescopic clamp is arranged in matching with the first fixed plate sliding groove, and the first part comprises two side clamping plates connected with the first fixed main plate perpendicularly and connected through the first telescopic clamp; The second part of the first clamping unit comprises a first fixed small main plate, a first fixed sliding groove and a telescopic clamp arranged on the first fixed small main plate, the second part comprises two small clamping plates arranged perpendicularly on both sides of the first fixed small main plate, and a first telescopic fixing device is arranged on the first fixed small main plate, the second part is connected with the first part, the two small clamping plates are stretched to a certain range and clamped outside the first fixed small main plate, the two small clamping plates are further stressed and tightened through the first telescopic fixing device, the stability is achieved, and the stability during the rotation movement is ensured; The first telescopic rod is lowered to a certain height and stretched to a proper length, the one end of the steel frame is clamped and precisely positioned through the first clamping unit, the first end head rotation device is driven to rotate by a certain angle around the first braking displacement sliding groove until the steel frame is moved to a position matched with the profile of the tunnel, the construction object is driven to rise to the third rotation braking mechanism through the second rotation braking mechanism, and the construction object is raised to the position matched with the profile of the tunnel lining through the third rotation braking mechanism, the automatic precise positioning of the profile of the construction object is realized, and the construction is formed; The second rotation braking mechanism comprises a second braking displacement sliding groove, a second telescopic rod connected with the second braking displacement sliding groove, and a second clamping unit arranged at one end of the second telescopic rod, after the rotation movement to the second rotation braking mechanism through the first rotation braking mechanism, the steel frame is lifted and conveyed to the position matched with the profile of the tunnel lining to realize the precise positioning, and the steel frame is accurately connected with other steel frame structures conveyed by the first rotation braking mechanism, and the welding forming is realized.

2. A tunnel multi-stage rotary braking trolley according to claim 1, characterized in that, The second clamping unit comprises symmetrically arranged second fixing plates, brake rollers mounted on the inner side of the second fixing plates connected with second telescopic rods, and common rollers arranged on the other second fixing plates.

3. A tunnel multi-stage rotary braking trolley according to claim 2, characterized in that, The second clamping unit comprises second telescopic fixing boxes arranged on the two sides of the second fixing plates respectively.

4. A tunnel multi-stage rotary braking trolley according to claim 3, characterized in that, The second clamping unit comprises second telescopic clamps arranged on the second telescopic fixing boxes, and second telescopic fixing devices arranged on the second telescopic fixing boxes.

5. A construction method for the tunnel multi-stage rotary braking trolley according to any one of claims 1-4, characterized in that, The method comprises the following steps: S100: The telescopic rod of the first rotating brake mechanism is lowered and elongated to a suitable length, the first rotating brake mechanism is used to stabilize one end of the steel frame on the ground, then the first rotating brake mechanism is started to make the steel frame stand in the inside of the tunnel excavation contour line, and then the telescopic rods at the upper and middle positions and the second rotating brake mechanism are used to clamp and fix the steel frame at the middle and upper positions; S200: The second rotating brake mechanism is used to start the roller brake, the fixed steel frame is transmitted to the vault above and the steel frames on the two sides are connected, the distance from the steel frame to the tunnel excavation contour line is adjusted through the telescopic rod, and after the steel frame at the same section is adjusted, the next welding work can be performed; S300: The brake sliding groove arranged on the trolley is used to move the working surface of the stand, and the cycle work is performed; S400: In the drilling process, the drilling pick supporting rod is stabilized in the inside of the clamping unit at each layer, the position and direction of the drilling pick are controlled through the adjustment of the direction of the clamping unit, the length of the telescopic rod and the brake sliding groove; S500: After use, the telescopic rod is retracted and bound and fixed in the inside of the trolley frame through the brake sliding groove and the rotating brake device connected with the trolley, so that the telescopic rod is prevented from being damaged.

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