Electric vehicle frame connecting plate laser cutting machine with positioning structure

Abstract

This utility model relates to the field of laser cutting machine technology, and in particular to a laser cutting machine for electric vehicle frame connecting pieces with a positioning structure. It includes a laser cutting device, a fixed base, a slide rail, a hydraulic rod, a positioning frame, an inner cavity, a mounting frame, guide wheels, a hydraulic cylinder, a connecting frame, rotating wheels, a sliding assembly, a drive motor, and a collecting assembly. The laser cutting device has a fixed base inside, a slide rail fixed above the fixed base, a hydraulic rod fixed above the slide rail, a positioning frame fixed at the upper end of the hydraulic rod, a mounting frame fixed at the top of the positioning frame, guide wheels rotating inside the mounting frame, and rotating wheels rotating inside the connecting frame. This laser cutting machine for electric vehicle frame connecting pieces with a positioning structure is suitable for producing multiple varieties and small batches of electric vehicle frame connecting pieces, enabling continuous and precise positioning and cutting of the connecting piece sheet material.

Description

Technical Field

[0001] This utility model relates to the field of laser cutting machine technology, and in particular to a laser cutting machine for electric vehicle frame connecting pieces with a positioning structure. Background Technology

[0002] Against the backdrop of the booming development of the new energy transportation industry, electric vehicles, as the core carrier of green travel tools, are increasingly demanding in terms of the precision and intelligence of their manufacturing processes. As a key component in the structure of electric vehicles, the frame connecting piece undertakes the important functions of connecting the frame, transmitting loads, and ensuring the safety of the entire vehicle. Its processing precision directly determines the stability and durability of the frame.

[0003] When laser cutting machines are in use, traditional laser cutting machines mostly adopt simple mechanical limiting structures, and the cutting size adjustment relies on manual calibration. This results in problems such as large fluctuations in positioning accuracy and complex operation. Especially in the mode of multi-variety, small-batch production, frequent adjustment of positioning parameters will significantly reduce production efficiency. In addition, conventional unloading methods mostly use free fall, which poses a risk of workpiece falling and being damaged after cutting. At the same time, the feeding mechanism of traditional equipment mostly relies on a fixed support platform. The bottom of the connecting plate material and the platform surface will generate sliding friction. The feeding resistance increases sharply with the size of the connecting plate material, which can easily cause the connecting plate material to shift or surface scratches, resulting in a decrease in the finished product qualification rate.

[0004] Therefore, to address the issue of continuous and precise positioning and cutting of connecting sheet metal in small-batch production scenarios for vehicle frame connecting sheets, a laser cutting machine for electric vehicle frame connecting sheets with a positioning structure can be designed. This device's positioning system employs a gear and rack meshing transmission combined with hydraulic lifting, along with a double rolling support structure to ensure stable conveying of the connecting sheet metal, reducing cutting dimensional errors. A hydraulically driven tilting unloading mechanism replaces traditional manual material handling, shortening the unloading time per cycle and effectively improving production efficiency. A three-stage unloading guide system effectively prevents surface scratches on the connecting sheet metal, increasing the finished product qualification rate. In summary, this device is suitable for the production of sheet metal parts such as electric vehicle frame connecting sheets that require high-precision and high-efficiency processing, and is applicable to multi-variety, small-batch production scenarios for electric vehicle frame connecting sheets, thus enabling continuous and precise positioning and cutting of the connecting sheet metal. Utility Model Content

[0005] To overcome the problem that traditional laser cutting machines rely on fixed support platforms for their feeding mechanisms, which cause sliding friction between the bottom of the connecting sheet and the platform surface, leading to sheet misalignment, and that traditional laser cutting machines often use simple mechanical limiting structures, which, especially in multi-variety, small-batch production modes, require frequent adjustments to positioning parameters, significantly reducing production efficiency and making it difficult to achieve continuous and precise positioning and cutting of the connecting sheet.

[0006] The technical solution of this utility model is as follows: a laser cutting machine for electric vehicle frame connecting pieces with a positioning structure, including a laser cutting device, a fixed base, a slide rail, a hydraulic rod, a positioning frame, an inner cavity, a mounting frame, a guide wheel, a hydraulic cylinder, a connecting frame, a rotating wheel, a sliding component, a drive motor, and a collecting component. The laser cutting device has a fixed base inside, a slide rail fixed above the fixed base, a hydraulic rod fixed above the slide rail, a positioning frame fixed at the upper end of the hydraulic rod, an inner cavity inside the positioning frame, a mounting frame fixed at the top of the positioning frame, a guide wheel rotatably mounted inside the mounting frame, a hydraulic cylinder fixed inside the fixed base, a connecting frame fixed at the upper end of the hydraulic cylinder, a rotating wheel rotatably mounted inside the connecting frame, a sliding component inside the slide rail, a drive component inside the fixed base, and a collecting component on one side of the fixed base.

[0007] Preferably, when the laser cutting machine is in use, during the positioning of the connecting sheet material for cutting, the operator first activates the hydraulic rod to drive the positioning frame to rise and fall vertically. The hydraulic system precisely controls the upper edge of the positioning frame's inner cavity to the cutting height, which corresponds to the required thickness of the connecting sheet material. Then, the side wall of the positioning frame's inner cavity accurately stops at the preset cutting size position. During the connecting sheet material feeding stage, the bottom of the connecting sheet material contacts the rotating wheel driven by the hydraulic cylinder. When the feeder pushes the connecting sheet material, the bottom of the connecting sheet material forms rolling friction with the rotating wheel, significantly reducing feeding resistance. Since limit plates are fixedly installed on both sides of the rotating wheel and the sliding wheel, it can be ensured that the connecting sheet material maintains precise horizontal movement during sliding feeding. When the end of the connecting sheet material precisely abuts against the vertical reference surface of the positioning frame's inner cavity, the laser cutting head starts according to the preset program, performing precise contour cutting along the surface of the connecting sheet material. After cutting, the automated unloading process begins, first causing the positioning frame to move backward. After releasing the end constraint of the connecting sheet material, the hydraulic rod is lowered, causing the top guide wheel of the positioning frame to drop below the bottom surface of the connecting sheet material. At this time, the hydraulic cylinder is activated, lifting the rotating wheel to a set height via the connecting frame, causing the connecting sheet material support system to change from a horizontal to an inclined state. Under the action of gravity, the connecting sheet material slides down and is unloaded along the rotating wheel and guide wheel. The positioning system of this device uses gear and rack meshing transmission and hydraulic lifting in coordination, combined with a double rolling support structure to ensure the smooth conveying of the connecting sheet material, thereby reducing cutting size errors. The hydraulically driven inclined unloading mechanism replaces traditional manual material handling, shortening the unloading time per cycle and effectively improving production efficiency. The three-stage unloading guide system effectively avoids scratches on the surface of the connecting sheet material, improving the finished product qualification rate. In summary, this device is suitable for the production of sheet metal parts such as electric vehicle frame connecting pieces that require high-precision and high-efficiency processing. It is suitable for multi-variety, small-batch production scenarios of electric vehicle frame connecting pieces, and can achieve continuous and precise positioning and cutting of connecting sheet materials.

[0008] Preferably, the sliding assembly includes a slide groove, a slide rod, and a slide seat. The slide groove is provided inside the slide rail, the slide rod is fixedly installed inside the slide groove, and the slide seat is provided on the side wall of the slide rod.

[0009] Preferably, the slide block and the slide rod are slidably connected, and the bottom of the slide block is fixedly connected to the lower end of the hydraulic rod.

[0010] Preferably, the drive assembly includes an adjusting motor, an adjusting shaft, and an adjusting gear. The adjusting motor is fixedly installed inside the fixed base, the adjusting shaft is installed at the output end of the adjusting motor, and the adjusting gear is fixedly installed at one end of the adjusting shaft.

[0011] Preferably, the drive assembly also includes an adjusting gear plate, and the adjusting gear plate is fixedly provided on the bottom wall of the slide, with the adjusting gear meshing with the adjusting gear plate.

[0012] Preferably, the collecting component includes a discharge rack, discharge wheels, and a receiving rack. The discharge rack is provided on one side of the fixed base, and multiple sets of discharge wheels are provided inside the discharge rack. Both ends of the discharge wheels are rotatably connected to the inner wall of the discharge rack, and the receiving rack is provided on one side of the discharge rack.

[0013] Preferably, a fixing frame is fixedly installed above the fixing base, and a sliding wheel is rotatably installed inside the fixing frame.

[0014] The beneficial effects of this utility model are:

[0015] When using a laser cutting machine, during the positioning of the connecting sheet material for cutting, the operator first activates the hydraulic rod to drive the positioning frame to rise and fall vertically. The hydraulic system precisely controls the upper edge of the positioning frame's inner cavity to the cutting height, which corresponds to the required thickness of the connecting sheet material. Then, the inner wall of the positioning frame accurately stops at the preset cutting dimension. During the connecting sheet material feeding stage, the bottom of the sheet material contacts the rotating wheel driven by the hydraulic cylinder. As the feeder pushes the connecting sheet material, the bottom of the sheet material forms rolling friction with the rotating wheel, significantly reducing feeding resistance. Because limit plates are fixed on both sides of the rotating wheel and sliding wheel, it ensures that the connecting sheet material maintains precise horizontal movement during sliding feeding. When the end of the connecting sheet material precisely abuts against the vertical reference surface of the positioning frame's inner cavity, the laser cutting head starts according to the preset program, performing precise contour cutting along the surface of the connecting sheet material. After cutting, the automated unloading process begins, first moving the positioning frame backward to release the connecting sheet material. The end of the connecting sheet metal is constrained. Then, the hydraulic rod is activated to lower the guide wheel at the top of the positioning frame below the bottom surface of the connecting sheet metal. At this time, the hydraulic cylinder is activated to lift the rotating wheel to a set height through the connecting frame, so that the supporting system of the connecting sheet metal changes from a horizontal state to an inclined state. Under the action of gravity, the connecting sheet metal slides down and is unloaded along the rotating wheel and guide wheel. The positioning system of this device uses gear and rack meshing transmission and hydraulic lifting in coordination, and the double rolling support structure ensures the smooth conveying of the connecting sheet metal, reducing the cutting size error. The hydraulically driven inclined unloading mechanism replaces the traditional manual material handling, shortening the unloading time per cycle and effectively improving production efficiency. The three-stage unloading guide system effectively avoids scratches on the surface of the connecting sheet metal, improving the finished product qualification rate. In summary, this device is suitable for the production of sheet metal parts such as electric vehicle frame connecting pieces that require high precision and high efficiency processing. It is suitable for multi-variety, small-batch production scenarios of electric vehicle frame connecting pieces, and can achieve continuous and precise positioning and cutting of connecting sheet metal. Attached Figure Description

[0016] Figure 1 The diagram shown is a first three-dimensional structural schematic of the laser cutting machine for electric vehicle frame connecting pieces with a positioning structure according to this utility model.

[0017] Figure 2 The diagram shown is a partial three-dimensional structural schematic of the laser cutting machine for electric vehicle frame connecting pieces with positioning structure according to this utility model.

[0018] Figure 3 The diagram shown is a first half-section three-dimensional structural diagram of the fixing seat of the laser cutting machine for electric vehicle frame connecting piece with positioning structure according to this utility model.

[0019] Figure 4The diagram shown is a three-dimensional structural diagram of the first outer periphery of the slide bar of the laser cutting machine for the electric vehicle frame connecting piece with positioning structure according to this utility model.

[0020] Explanation of reference numerals in the attached drawings: 1. Laser cutting equipment; 2. Fixed base; 3. Slide rail; 4. Hydraulic rod; 5. Positioning frame; 6. Inner cavity; 7. Mounting bracket; 8. Guide wheel; 9. Hydraulic cylinder; 10. Connecting bracket; 11. Rotating wheel; 12. Slide groove; 13. Slide rod; 14. Slide seat; 15. Adjusting motor; 16. Adjusting shaft; 17. Adjusting gear; 18. Adjusting toothed plate; 19. Discharge rack; 20. Discharge wheel; 21. Receiving rack; 22. Fixed bracket; 23. Sliding wheel. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Please see Figure 1 and Figure 2 This utility model provides an embodiment of a laser cutting machine for electric vehicle frame connecting pieces with a positioning structure, including a laser cutting device 1, a fixed base 2, a slide rail 3, a hydraulic rod 4, a positioning frame 5, an inner cavity 6, a mounting frame 7, a guide wheel 8, a hydraulic cylinder 9, a connecting frame 10, a rotating wheel 11, a sliding component, a drive motor, and a collecting component. The laser cutting device 1 has a fixed base 2 inside, a slide rail 3 fixedly mounted above the fixed base 2, a hydraulic rod 4 fixedly mounted above the slide rail 3, a positioning frame 5 fixedly mounted at the upper end of the hydraulic rod 4, an inner cavity 6 inside the positioning frame 5, a mounting frame 7 fixedly mounted at the top of the positioning frame 5, a guide wheel 8 rotatably mounted inside the mounting frame 7, a hydraulic cylinder 9 fixedly mounted inside the fixed base 2, a connecting frame 10 fixedly mounted at the upper end of the hydraulic cylinder 9, a rotating wheel 11 rotatably mounted inside the connecting frame 10, a sliding component inside the slide rail 3, a drive component inside the fixed base 2, and a collecting component on one side of the fixed base 2.

[0023] Please see Figure 2 and Figure 3The sliding assembly includes a slide groove 12, a slide rod 13, and a slide seat 14. The slide rail 3 has a slide groove 12 inside, and a slide rod 13 is fixedly installed inside the slide groove 12. The slide seat 14 is installed on the side wall of the slide rod 13. The guide pair formed by the slide rod 13 and the slide groove 12 ensures the straightness of the moving trajectory of the positioning frame 5. The slide seat 14 is slidably connected to the slide rod 13. The bottom of the slide seat 14 is fixedly connected to the lower end of the hydraulic rod 4. The guide pair formed by the slide rod 13 and the slide groove 12 ensures the straightness of the moving trajectory of the positioning frame 5. The driving assembly includes an adjusting motor 15, an adjusting shaft 16, and an adjusting gear 17. The adjusting motor 15 is fixedly installed inside the fixed base 2. The adjusting shaft 16 is installed at the output end of the adjusting motor 15. The adjusting gear 17 is fixedly installed at one end of the adjusting shaft 16. Starting the adjusting motor 15 drives the adjusting shaft 16 and the adjusting gear 17 to rotate.

[0024] Please see Figure 2 and Figure 4 The drive assembly also includes an adjusting gear plate 18. The adjusting gear plate 18 is fixedly installed on the bottom wall of the slide 14. The adjusting gear 17 meshes with the adjusting gear plate 18. The rotational movement of the adjusting shaft 16 can drive the adjusting gear 17 to mesh with the adjusting gear plate 18 fixed at the bottom of the slide 14, so that the slide 14 can perform high-precision horizontal displacement along the slide rod 13 embedded in the slide rail 3. The collection assembly includes a discharge rack 19, a discharge wheel 20, and a receiving rack 21. The discharge rack 19 is installed on one side of the fixed base 2. The interior is equipped with multiple sets of discharge wheels 20. Both ends of the discharge wheels 20 are rotatably connected to the inner wall of the discharge frame 19. A receiving frame 21 is provided on one side of the discharge frame 19. The connecting sheet material slides down along the rotating wheel 11 and the guide wheel 8 into the interior of the discharge frame 19 under the action of gravity. Then, it slides down into the interior of the feeding frame through the multiple sets of discharge wheels 20. A fixing frame 22 is fixedly provided above the fixing seat 2. A sliding wheel 23 is rotatably provided inside the fixing frame 22. The sliding wheel 23 can ensure the smooth conveying of the connecting sheet material.

[0025] When the laser cutting machine is in use, when positioning the cutting position of the connecting sheet material, the operator first starts the hydraulic rod 4 to drive the positioning frame 5 to rise and fall vertically. The hydraulic system precisely controls the upper edge of the inner cavity 6 of the positioning frame 5 to the cutting height, which corresponds to the required thickness standard of the connecting sheet material to be cut.

[0026] Subsequently, the adjustment motor 15 is started to drive the adjustment shaft 16 to rotate. The rotation of the adjustment shaft 16 can drive the adjustment gear 17 to mesh with the adjustment tooth plate 18 fixed at the bottom of the slide block 14, so that the slide block 14 can perform high-precision horizontal displacement along the slide rod 13 embedded in the slide rail 3. During this process, the guide pair formed by the slide rod 13 and the slide groove 12 ensures the straightness of the movement trajectory of the positioning frame 5. The displacement accuracy is precisely controlled by the gear and rack transmission ratio, so that the side wall of the inner cavity 6 of the positioning frame 5 is accurately stopped at the preset cutting size position.

[0027] During the feeding stage of the connecting sheet material, the bottom of the connecting sheet material to be processed contacts the rotating wheel 11 driven by the hydraulic cylinder 9 and the sliding wheel 23 on the fixed frame 22 one by one. When the feeding machine pushes the connecting sheet material, the bottom of the connecting sheet material forms rolling friction with the rotating wheel 11 and the sliding wheel 23, which significantly reduces the feeding resistance. Since the rotating wheel 11 and the sliding wheel 23 are fixedly provided with limit plates on both sides, it can be ensured that the connecting sheet material maintains precise horizontal movement during the sliding feeding process. When the end of the connecting sheet material accurately abuts against the vertical reference surface of the inner cavity 6 of the positioning frame 5, the laser cutting head starts according to the preset program and performs precise contour cutting along the surface of the connecting sheet material.

[0028] After cutting, the automated unloading process begins. The regulating motor 15 is started and continuously driven to move the positioning frame 5 backward and release the constraint at the end of the connecting plate material. Then, the hydraulic rod 4 is started to descend, so that the top guide wheel 8 of the positioning frame 5 is lowered below the bottom surface of the connecting plate material. At this time, the hydraulic cylinder 9 is started, and the rotating wheel 11 is lifted to the set height through the connecting frame 10, so that the connecting plate material support system changes from a horizontal state to an inclined state. Under the action of gravity, the connecting plate material slides down along the rotating wheel 11, the sliding wheel 23 and the guide wheel 8 into the interior of the discharge rack 19. Then, it slides down into the interior of the loading rack through multiple sets of discharge wheels 20. The multiple sets of discharge wheels 20 adopt a stepped layout and use the gravity component to realize the automatic stacking of the connecting plate material.

[0029] The positioning system of this device uses a gear and rack meshing transmission combined with hydraulic lifting, along with a double rolling support structure to ensure the smooth conveying of the connecting sheet material, thereby reducing cutting size errors. The hydraulically driven tilting unloading mechanism replaces traditional manual material handling, shortening the unloading time per cycle and effectively improving production efficiency. The three-stage unloading guide system effectively avoids scratches on the surface of the connecting sheet material, improving the finished product qualification rate. In summary, this device is suitable for the production of sheet metal parts such as electric vehicle frame connecting pieces that require high-precision and high-efficiency processing. It is suitable for multi-variety, small-batch production scenarios of electric vehicle frame connecting pieces, and can achieve continuous and precise positioning and cutting of connecting sheet material.

[0030] Through the above steps, when the laser cutting machine is in use, during the positioning of the connecting sheet material for cutting, the operator first activates the hydraulic rod 4 to drive the positioning frame 5 to rise and fall vertically. The hydraulic system precisely controls the upper edge of the inner cavity 6 of the positioning frame 5 to the cutting height, which corresponds to the required thickness standard of the connecting sheet material to be cut. Then, the side wall of the inner cavity 6 of the positioning frame 5 is accurately positioned at the preset cutting size. During the connecting sheet material feeding stage, the bottom of the connecting sheet material to be processed contacts the rotating wheel 11 driven by the hydraulic cylinder 9. When the feeder pushes the connecting sheet material, the bottom of the connecting sheet material forms rolling friction with the rotating wheel 11, significantly reducing feeding resistance. Since limit plates are fixedly installed on both sides of the rotating wheel 11 and the sliding wheel 23, it can be ensured that the connecting sheet material maintains precise horizontal movement during sliding feeding. When the end of the connecting sheet material precisely abuts against the vertical reference surface of the inner cavity 6 of the positioning frame 5, the laser cutting head starts according to the preset program, performing precise contour cutting along the surface of the connecting sheet material. After cutting, it enters the automated unloading process. First, the positioning... After frame 5 moves backward to release the constraint at the end of the connecting plate, hydraulic rod 4 is activated to lower the top guide wheel 8 of positioning frame 5 below the bottom surface of the connecting plate. At this time, hydraulic cylinder 9 is activated to lift rotating wheel 11 to a set height through connecting frame 10, so that the connecting plate support system changes from a horizontal state to an inclined state. Under the action of gravity, the connecting plate slides down and is unloaded along rotating wheel 11 and guide wheel 8. The positioning system of this device adopts gear and rack meshing transmission and hydraulic lifting in coordination, and with the double rolling support structure, it ensures the smooth conveying of connecting plate, reduces cutting size error, and the hydraulically driven inclined unloading mechanism replaces the traditional manual material handling, shortening the single unloading time and effectively improving production efficiency. The three-stage unloading guide system effectively avoids scratches on the surface of the connecting plate, and improves the finished product qualification rate. In summary, this device is suitable for the production of sheet metal parts such as electric vehicle frame connecting plates that require high precision and high efficiency processing. It is suitable for the production scenario of electric vehicle frame connecting plates with multiple varieties and small batches, and can achieve continuous and accurate positioning and cutting of connecting plate materials.

[0031] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An electric vehicle frame connecting piece laser cutting machine with positioning structure, comprising a laser cutting device (1), characterized in that: It also includes a fixed base (2), a slide rail (3), a hydraulic rod (4), a positioning frame (5), an inner cavity (6), a mounting bracket (7), a guide wheel (8), a hydraulic cylinder (9), a connecting frame (10), a rotating wheel (11), a sliding assembly, a drive motor, and a collecting assembly. The laser cutting equipment (1) is internally fixedly equipped with a fixed base (2), a slide rail (3) is fixedly installed above the fixed base (2), a hydraulic rod (4) is fixedly installed above the slide rail (3), and a positioning frame (5) is fixedly installed at the upper end of the hydraulic rod (4). The positioning frame (5) has an inner cavity (6) inside. A mounting bracket (7) is fixedly installed on the top of the positioning frame (5). A guide wheel (8) is rotatably installed inside the mounting bracket (7). A hydraulic cylinder (9) is fixedly installed inside the fixed seat (2). A connecting frame (10) is fixedly installed at the upper end of the hydraulic cylinder (9). A rotating wheel (11) is rotatably installed inside the connecting frame (10). A sliding component is installed inside the slide rail (3). A driving component is installed inside the fixed seat (2). A collecting component is installed on one side of the fixed seat (2).

2. The electric vehicle frame rail laser cutting machine with positioning structure according to claim 1, characterized in that: The sliding assembly includes a slide groove (12), a slide rod (13) and a slide seat (14). The slide rail (3) has a slide groove (12) inside, and a slide rod (13) is fixedly installed inside the slide groove (12). A slide seat (14) is installed on the side wall of the slide rod (13).

3. The electric vehicle frame rail laser cutting machine with positioning structure according to claim 2, characterized in that: The slide block (14) is slidably connected to the slide rod (13), and the bottom of the slide block (14) is fixedly connected to the lower end of the hydraulic rod (4).

4. The electric vehicle frame rail laser cutting machine with positioning structure according to claim 2, characterized in that: The drive assembly includes an adjustment motor (15), an adjustment shaft (16), and an adjustment gear (17). The adjustment motor (15) is fixedly installed inside the fixed base (2). The output end of the adjustment motor (15) is provided with an adjustment shaft (16), and one end of the adjustment shaft (16) is fixedly provided with an adjustment gear (17).

5. The electric vehicle frame rail laser cutting machine with positioning structure according to claim 4, characterized in that: The drive assembly also includes an adjusting toothed plate (18), and the adjusting toothed plate (18) is fixedly installed on the bottom wall of the slide (14). The adjusting gear (17) meshes with the adjusting toothed plate (18).

6. The electric vehicle frame rail laser cutting machine with positioning structure according to claim 1, characterized in that: The collection assembly includes a discharge rack (19), discharge wheels (20) and a receiving rack (21). The discharge rack (19) is provided on one side of the fixed base (2). Multiple sets of discharge wheels (20) are provided inside the discharge rack (19). Both ends of the discharge wheels (20) are rotatably connected to the inner wall of the discharge rack (19). The receiving rack (21) is provided on one side of the discharge rack (19).

7. The electric vehicle frame rail laser cutting machine with positioning structure according to claim 1, characterized in that: A fixed frame (22) is fixedly installed above the fixed base (2), and a sliding wheel (23) is rotatably installed inside the fixed frame (22).

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