Automatic stereoscopic warehouse

Abstract

The invention relates to the technical field of stereoscopic warehouses, in particular to an automatic stereoscopic warehouse which comprises a track and a stereoscopic goods shelf arranged on the side portion of the track, a sensor is arranged at the groove bottom of the track, a stacking machine is arranged on the track, and when the stacking machine travels to the stereoscopic goods shelf along the track, the stacking machine stops moving. A sensor is arranged on the three-dimensional goods shelf, the sensor can be triggered to be powered on to work when the three-dimensional goods shelf moves, a loading platform is arranged on the three-dimensional goods shelf, trundles are arranged at the bottom of the three-dimensional goods shelf, locking assemblies are arranged between the loading platform and the trundles, the trundles can be locked once through the locking assemblies every time the loading platform moves, the back face of the goods is close to a correcting plate, and the correcting plate can correct the back face of the goods. The tray where the goods are located is corrected through the correcting plate, so that it is guaranteed that the inserting holes in the bottom face of the tray face forwards vertically, and when the stacking machine arrives at the set position of the three-dimensional goods shelf again to take the goods, the inserting rods can stretch into the tray more accurately, and the goods are taken down and transferred.

Description

Technical Field

[0001] The invention relates to the technical field of stereoscopic warehouses, in particular to an automated stereoscopic warehouse. Background Art

[0002] Three-dimensional warehouses are widely used in the logistics industry. They are composed of multiple three-dimensional shelves, tracks and stackers. In order to achieve automation, an intelligent control system is set up in the warehouse. A large number of sensors are used for fixed-point detection. Multi-point detection technology is used to control the stacker to automatically store and retrieve goods according to the shelf position. This not only saves labor and improves work efficiency, but also avoids errors when storing and retrieving goods.

[0003] After the stacker places the goods on the shelf, it will quickly pull out the insertion rod from the bottom of the goods. At this time, inertial force will be generated between the insertion rod and the bottom of the goods. When the insertion rod is quickly pulled out, the goods will be tilted on the shelf. When the stacker inserts the goods again, there will be a positioning deviation between the insertion rod and the bottom of the goods. When inserting and transferring, the goods will be tilted on the insertion rod, and the force is uneven, which poses a safety hazard when picking up and transferring goods. Summary of the invention

[0004] In order to solve the above problems, the present invention provides an automated three-dimensional warehouse, including a track and a three-dimensional shelf arranged on the side of the track, a sensor is arranged in the three-dimensional warehouse, a stacker is arranged on the track, and each time the stacker travels along the track to the three-dimensional shelf, the sensor will be triggered to be energized, a loading platform is arranged on the three-dimensional shelf, an electric cylinder electrically connected to the sensor is arranged on the loading platform, casters are provided at the bottom of the three-dimensional shelf, a locking assembly is provided between the loading platform and the casters, each time the loading platform moves, the casters are locked once by the locking assembly, a correction plate is provided on the side of the three-dimensional shelf, one side of the loading platform is close to the track, and the other side of the loading platform is away from the track, and the correction plate is away from the top of the other side of the track, and each time the sensor loses the stacker trigger, the electric cylinder is driven to drive the loading platform to move linearly along the three-dimensional shelf relative to the direction of the correction plate.

[0005] As further preferred, there are a plurality of sensors and a plurality of three-dimensional shelves, and the plurality of sensors are equidistantly arranged along the length direction of the track, and each sensor corresponds to one three-dimensional shelf.

[0006] As a further preferred embodiment, the three-dimensional shelf is composed of four columns distributed in a rectangular position and a rectangular reinforcement frame connected to the bottom of the four columns, and a caster is connected to the bottom end of each column.

[0007] As a further preferred embodiment, a guide sleeve passes through and is welded to each of the columns, the loading platform consists of a rectangular frame and a liner welded to both ends of the frame, the electric cylinder is connected to the column, the action rod of the electric cylinder is connected to the frame, the two ends of the correction plate are connected between the two columns on the same side, the two ends of the liner extend toward both sides of the width of the frame and are respectively inserted into the two guide sleeves on the same side, and the two ends of the frame are provided with a bending portion away from the movable gap formed between the inner side of the liner and the column.

[0008] As a further preferred embodiment, the guide sleeve is filled with a reinforcing tube, the outer end of the reinforcing tube is welded with a limiting ring, the limiting ring is limited to the outer end of the guide sleeve, the inner end of the reinforcing tube passes through the inner end of the guide sleeve and extends to the middle of the liner, and the two reinforcing tubes on the same side are connected by a tension spring.

[0009] As a further preferred embodiment, the column is a tube, and an assembly opening is opened inwardly from the tube wall of the column, the locking assembly includes a guide tube fixed in the tube cavity of the column, a locking rod perpendicular to the tube cavity of the column, and a spring elastically arranged between the locking rod and the guide tube, the top end of the locking rod extends from the assembly opening to the bottom of the bending portion, and is fixed with a lifting seat located below the bending portion and slidably fitted on the bottom surface of the bending portion, the locking assembly also includes an inclined seat fixed on the bottom surface of the bending portion, the bottom end of the locking rod enters the caster and is equipped with a locking seat located above the caster wheel.

[0010] As a further preference, the locking assemblies are in two groups and are only arranged on two columns on the same side as the correction plate.

[0011] As a further preferred embodiment, the lifting seat is provided with an arc-shaped groove which is slidably matched with the bottom surface of the bending portion, and the arc-shaped groove and the inclined seat are in the same straight line.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1. The bottom of the three-dimensional shelf is provided with casters. Although some traditional cargo racks also have casters at the bottom, the bottom of the three-dimensional shelf in the three-dimensional warehouse is fixed in the warehouse. The present invention retains casters at the bottom of the three-dimensional shelf 2 to facilitate daily management.

[0014] 2. Combining the intelligence of the three-dimensional warehouse and the control relationship between the sensor and the stacker, the stacker moves to the shelf and stacks the goods on the loading platform of the three-dimensional shelf. Then, when it leaves the three-dimensional shelf along the track, the distance signal detected by the sensor controls the electric cylinder to energize, and the electric cylinder moves the loading platform toward one side of the correction plate. Driven by the loading platform, the goods move toward the correction plate, so that the back of the goods leans against the correction plate, and the correction plate adjusts the pallet where the goods are located to ensure that the socket on the bottom of the pallet is vertically facing forward. When the stacker reaches the set position of the three-dimensional shelf again to pick up the goods, it can more accurately extend the insertion rod into the pallet, remove the goods and transfer them.

[0015] 3. The types of sensors also include pressure sensors installed on the loading platform. When the stacker places the goods on the loading platform, the pressure on the loading platform increases and triggers the pressure sensor to feedback a signal to the control system. The control system can also control the electric cylinder to energize and drive the loading platform to move toward one side of the correction plate. In addition to adjusting the goods and the back of the pallet where the goods are located against the correction plate, it will also trigger the locking assembly to lock the casters in advance. When loading and adjusting work is in progress, the three-dimensional shelf will not move. After loading and adjusting work is completed, the three-dimensional shelf will return to a free state that is convenient for daily management. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the distribution of three-dimensional shelves and tracks in an automated three-dimensional warehouse provided by an embodiment of the present invention;

[0017] Figure 2 The automated high-rise warehouse provided by the embodiment of the present invention comprises Figure 1 The enlarged schematic diagram of the A part is shown;

[0018] Figure 3 The automated high-rise warehouse provided by the embodiment of the present invention comprises Figure 1 The schematic diagram from the second perspective is introduced;

[0019] Figure 4 The automated high-rise warehouse provided by the embodiment of the present invention comprises Figure 3 The enlarged schematic diagram of the B part is shown;

[0020] Figure 5 A schematic diagram of a three-dimensional shelf in an automated three-dimensional warehouse provided in an embodiment of the present invention with a column at one end cut open;

[0021] Figure 6 A schematic diagram of a partial structure of a three-dimensional shelf in an automated three-dimensional warehouse provided in an embodiment of the present invention;

[0022] Figure 7A schematic diagram of two columns at one end of a three-dimensional shelf in an automated three-dimensional warehouse provided in an embodiment of the present invention;

[0023] Figure 8 The automated high-rise warehouse provided by the embodiment of the present invention comprises Figure 7 The enlarged schematic diagram of the C part is shown;

[0024] Fig. 9 A schematic diagram of a plurality of groups of three-dimensional cargo in an automated three-dimensional warehouse provided by an embodiment of the present invention after the loading platforms are removed from the three-dimensional shelves;

[0025] Fig.10 A diagram showing the relationship between multiple groups of three-dimensional shelves and tracks in an automated three-dimensional warehouse provided in an embodiment of the present invention.

[0026] In the figure: 1. track; 2. three-dimensional shelf; 21. column; 211. guide sleeve; 213. reinforcement tube; 216. assembly port; 22. rectangular reinforcement frame; 3. sensor; 4. loading platform; 41. frame; 411. bending part; 42. liner; 5. electric cylinder; 6. caster; 7. locking assembly; 71. guide tube; 72. locking rod; 73. spring; 74. lifting seat; 75. locking seat; 76. inclined seat; 8. correction plate; 9. movable gap.

[0027] Specific implementation party

[0028] The above and other embodiments and advantages of the present invention are described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments.

[0029] In one embodiment, if Figure 1-Figure 10 As shown:

[0030] The present embodiment provides an automated stereoscopic warehouse, comprising a track 1 and a stereoscopic shelf 2 arranged on the side of the track 1. A sensor 3 is arranged in the stereoscopic warehouse. For example, as shown in the figure, the sensor 3 can be arranged in the bottom of the groove of the track 1 (distance sensor or pressure sensor), or can be arranged at other suitable positions in the warehouse. A stacker is arranged on the track 1. Every time the stacker travels along the track 1 to the stereoscopic shelf 2, the sensor 3 is triggered to be powered on. A loading platform 4 is arranged on the stereoscopic shelf 2. An electric cylinder 5 electrically connected to the sensor 3 is arranged on the loading platform 4. Casters 6 are provided at the bottom of the stereoscopic shelf 2. A locking assembly 7 is arranged between the loading platform 4 and the casters 6. Every time the loading platform 4 moves, the casters 6 are locked once by the locking assembly 7. A correction plate 8 is arranged on the side of the stereoscopic shelf 2. One side of the loading platform 4 is close to the track 1, and the other side of the loading platform 4 is away from the track 1. The correction plate 8 is far above the other side of the track 1. Every time the sensor 3 loses the stacker trigger, the electric cylinder 5 is driven to drive the loading platform 4 to move linearly along the direction of the stereoscopic shelf 2 relative to the correction plate 8.

[0031] like Fig.10 As shown and according to the automation setting of the existing three-dimensional warehouse, multiple rows of three-dimensional shelves 2 are set in the same warehouse, the number of sensors 3 is set to match the number of three-dimensional shelves 2, or multiple cargo storage units are set on each three-dimensional shelf 2, and corresponding sensors 3 corresponding to these storage units are set at multiple positions in the three-dimensional warehouse, and a track 1 is set between every two rows of three-dimensional shelves 2, and a stacker is set on the track 1. Under the control of the intelligent system, the stacker will move linearly along the track 1, and stack the goods at a certain position of a certain three-dimensional shelf 2 according to the instruction code, and can also transfer the goods at a certain position of a certain three-dimensional shelf 2 to the outside of the warehouse according to the instruction code. The present invention improves the three-dimensional shelf 2 on this basis, which is embodied as follows: First, the bottom of the three-dimensional shelf 2 is provided with casters 6. Although the bottom of some traditional cargo racks also has casters, the bottom of the three-dimensional shelf 2 in the three-dimensional warehouse is fixed in the warehouse. The present invention retains the casters 6 at the bottom of the three-dimensional shelf 2 to facilitate daily management.

[0032] Secondly, combining the transmission coordination relationship between the track 1 and the stacker, a sensor 3 is set on the track 1 or near the track 1 and at a reasonable position in the warehouse. The distance sensor 3 is connected to the infrared signal light on the stacker. When the stacker moves to a certain three-dimensional shelf 2 and, under the control of the control system, stacks the goods on the loading platform 4 of the three-dimensional shelf 2 (stacked on the opposite side of the correction plate 8), the stacker is close to the sensor 3 and does not send an infrared signal at this time. The stacker puts the goods on the loading platform 4 and then leaves the three-dimensional shelf 2 along the track 1. At this time, the stacker will move away from the sensor 3. When the detected distance signal reaches the set value, the Zhitong control system controls the electric cylinder 5 to be energized, and the electric cylinder 5 moves the loading platform 4 toward one side of the correction plate 8. The goods are driven by the loading platform 4 to move toward the correction plate 8, and the The back side is against the correction plate 8, which is a straight plate connected to the other side of the three-dimensional shelf 2. Therefore, when the back side of the goods is completely against the correction plate 8, the back side of the goods will be adjusted. If the goods are placed on a pallet, and the pallet is dragged by the stacker and placed on the loading platform 4, when the loading platform 4 moves toward one side of the correction plate 8, the back side of the pallet is actually against the correction plate 8, and the pallet is adjusted by the correction plate 8 to ensure that the socket on the bottom of the pallet is vertically facing forward. The stacker is equipped with a plug rod (similar to the front fork of a forklift). When the control system controls the stacker to reach a certain set position of the three-dimensional shelf 2 to pick up the goods, the plug rod is accurately inserted into the socket of the pallet, which is more effective for automated picking. As for the adjustment mechanism used, only the loading platform 4 is set to be mobile, and the correction plate 8 is only set on its back side, which has a simple structure.

[0033] In addition, when the goods are adjusted by moving the loading platform 4, the overall displacement of the three-dimensional shelf 2 will inevitably occur, which will bring inconvenience to the adjustment work. Therefore, a locking component 7 is provided on the three-dimensional shelf 2. The locking component 7 will be triggered when the loading platform 4 moves as mentioned above, and the caster 6 will be locked by the locking component 7.

[0034] In another embodiment, if Figures 1 to 8As shown, the external structure of the three-dimensional shelf 2 is a rectangular frame composed of four columns 21 and a rectangular reinforcement frame 22 connected to the bottom of the four columns 21. A caster 6 is connected to the bottom end of each column 21. The loading platform 4 is set on the three-dimensional shelf 2 as a shelf. The two ends of the correction plate 8 are connected between the two columns 21 on the same side (the opposite side of the loading side); in addition, a guide sleeve 211 is passed through and welded on each column 21. The loading platform 4 is composed of a rectangular frame 41 and a liner 42 welded to the two ends of the frame 41. The electric cylinder 5 is connected to the column 21, and the action rod of the electric cylinder 5 is connected to the frame 41. The two ends of the correction plate 8 are connected between the two columns 21 on the same side. The two ends of the liner 42 extend toward the width sides of the frame 41 and are respectively inserted into the two guide sleeves 211 on the same side. The frame 41 is filled with reinforcing rods for carrying goods. When the goods are placed on the frame 41 through a pallet, they sit on these reinforcing rods. When the electric cylinder 5 is energized, it drives the frame 41 to move, and the liner 42 at the two ends of the frame 41 move along the guide sleeves 211. When the frame 41 moves, in order to prevent its two ends from being stuck on the column 21, a bending portion 411 is also provided at both ends of the frame 41, and a movable gap 9 is formed between the bending portion 411 and the column 21.

[0035] like Figure 5 , Figure 8 as well as Fig. 9 As shown, each guide sleeve 211 is filled with a reinforcing tube 213, and a limiting ring 214 is welded to the outer end of the reinforcing tube 213. The limiting ring 214 is located at the outer end of the guide sleeve 211. The inner end of the reinforcing tube 213 passes through the inner end of the guide sleeve 211 and extends to the middle of the liner 42. The two reinforcing tubes 213 on the same side are connected by a tension spring. When each liner 42 moves along the guide sleeve 211, the two reinforcing tubes 213 on the same side are connected together by welding a tension spring, and they are located in the liner 42 of the loading platform 4. For example, when the loading platform 4 moves (the liner 42 moves along the guide sleeve 211) and moves with the goods toward the correction plate 8, although the correction plate 8 holds the goods in place, The back side of the pallet is adjusted, but the goods gain weight on one side of the correction plate 8, causing the shelf to lose weight on one side, that is, the liner 42 bears a larger load on the single-sided guide sleeve 211. Since a reinforcing tube 213 is provided in the liner 42, and the outer end of the reinforcing tube 213 extends to the outer end of the guide sleeve 211, and the inner end extends to the middle of the tube cavity of the liner 42, and a reinforcing tube 213 is also extended into the other side of the tube cavity from the guide sleeve 211 on the other side, the reinforcing tube 213 increases the strength of the guide sleeve 211. Even if the single-sided guide sleeve 211 loses weight when the loading platform 4 moves on one side, the single-sided guide sleeve 211 will not be deformed due to excessive single-sided force, thereby improving the strength of the three-dimensional shelf 2.

[0036] In another embodiment, if Figure 5 , Fig. 9As shown, the column 21 is a pipe, and an assembly port 216 is opened inwardly from the pipe wall of the column 21. The locking assembly 7 consists of two groups, which are only arranged in the two columns 21 on the same side as the correction plate 8. The locking assembly 7 includes a guide tube 71 fixed in the tube cavity of the column 21, a locking rod 72 perpendicular to the tube cavity of the column 21, and a spring 73 elastically arranged between the locking rod 72 and the guide tube 71. The top end of the locking rod 72 extends from the assembly port 216 to the bottom of the bending portion 411, and is fixed with a lifting seat 74 located below the bending portion 411 and slidably matched with the bottom surface of the bending portion 411. The locking assembly 7 also includes an inclined seat 76 fixed on the bottom surface of the bending portion 411. The bottom end of the locking rod 72 enters the caster 6 and is installed with a positioning seat When the frame 41 moves the liner 42 toward one side of the correction plate 8 (when the loading platform 4 moves toward one side of the correction plate 8 driven by the electric cylinder 5), in addition to placing the goods or the back of the pallet on which the goods are located against the correction plate 8, the liner 42 will also move with the bending portion 411, and the bending portion 411 will move with the inclined seat 76, so that the inclined seat 76 enters the arc-shaped groove 731 of the lifting seat 74, and uses the inclined surface on the inclined seat 76 to squeeze the lifting seat 74, forcing the lifting seat 74 to descend, and the lifting seat 74 descends with the locking rod 72, the spring 73 is compressed and shortened, and the locking rod 72 drives the locking seat 75 to descend, so that the locking seat 75 falls on the caster 6, so that the caster 6 is automatically locked. The purpose of the loading platform 4 moving toward one side of the correction plate 8 is to adjust the goods or the pallet where the goods are located. At this time, the caster 6 is locked in advance through the above-mentioned driving method. When the goods or the pallet where the goods are located are adjusted, the three-dimensional shelf 2 is prevented from being displaced as a whole due to the movement of the loading platform 4. In actual use, a timing module is provided in the intelligent control system. When the goods are adjusted, the electric cylinder 5 brings the loading platform 4 to reset toward the loading side, the liner 42 brings the bending part 411 and the bending part 411 brings the inclined seat 76 away from the lifting seat 74, the spring 73 resets and becomes longer, and drives the locking rod 72 to reset upward, and the locking rod 72 drives the locking seat 75 to separate from the caster 6, and the caster 6 is free, that is, the three-dimensional shelf 2 is free.

[0037] In addition, the types of sensors 3 also include pressure sensors arranged on the loading platform 4. When the stacker places the goods on the loading platform 4, the pressure on the loading platform 4 increases and triggers the pressure sensor to feedback a signal to the control system. At this time, the control system can also control the electric cylinder 5 to be energized, driving the loading platform 4 to move toward one side of the correction plate 8. In addition to adjusting the goods and the back of the pallet where the goods are located against the correction plate 8, it will also trigger the locking assembly 7 to lock the caster 6 in advance. When loading and adjusting work is in progress, the three-dimensional shelf 2 will not move. After the loading and adjustment work is completed, the three-dimensional shelf 2 is free, which is convenient for daily management.

[0038] The three-dimensional warehouse is intelligent, and the intelligent control system mentioned in the present invention is its inherent technology, which will not be described in detail in the present invention. The various reference positions mentioned in the present invention do not represent the inherent positions in the viewing angles of the various views in this embodiment. This embodiment is only for the convenience of describing the scheme, and the relative description and setting of the positions with reference to the figures are made. In essence, the specific positions of each component are described according to their actual installation and actual use, as well as the positions customary by those skilled in the art. This is hereby explained.

[0039] The specific implementation methods described above further describe the invention purpose, technical solutions, and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the protection scope of the present invention. It is particularly pointed out that for those skilled in the art, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Automated high-bay warehouse, characterized by: The invention comprises a track (1) and a three-dimensional shelf (2) arranged on the side of the track (1), a sensor (3) is arranged in the three-dimensional warehouse, a stacker is arranged on the track (1), and each time the stacker moves along the track (1) to the three-dimensional shelf (2), the sensor (3) is triggered to be powered on, a loading platform (4) is arranged on the three-dimensional shelf (2), an electric cylinder (5) electrically connected to the sensor (3) is arranged on the loading platform (4), and casters (6) are arranged at the bottom of the three-dimensional shelf (2), and a locking assembly is arranged between the loading platform (4) and the casters (6) (7), each time the loading platform (4) moves, the caster (6) is locked once by the locking assembly (7), a correction plate (8) is provided on the side of the three-dimensional shelf (2), one side of the loading platform (4) is close to the track (1), and the other side of the loading platform (4) is away from the track (1), and the correction plate (8) is far above the other side of the track (1), and each time the sensor (3) loses the stacker trigger, the electric cylinder (5) is driven to drive the loading platform (4) to move linearly along the three-dimensional shelf (2) relative to the correction plate (8).

2. The automated high-bay warehouse according to claim 1, characterized in that: There are a plurality of sensors (3) and a plurality of three-dimensional shelves (2). The plurality of sensors (3) are arranged equidistantly along the length direction of the track (1), and each sensor (3) corresponds to one three-dimensional shelf (2).

3. The automated high-bay warehouse according to claim 2, characterized in that: The three-dimensional shelf (2) is composed of four columns (21) distributed in a rectangular position and a rectangular reinforcement frame (22) connected to the bottom of the four columns (21), and the bottom end of each column (21) is connected to a caster (6).

4. The automated high-bay warehouse according to claim 3, characterized in that: A guide sleeve (211) passes through and is welded on each of the columns (21); the loading platform (4) is composed of a rectangular frame (41) and a liner (42) welded to both ends of the frame (41); the electric cylinder (5) is connected to the column (21); the action rod of the electric cylinder (5) is connected to the frame (41); the two ends of the correction plate (8) are connected between the two columns (21) on the same side; the two ends of the liner (42) extend toward both sides of the width of the frame (41) and are respectively inserted into the two guide sleeves (211) on the same side; and the two ends of the frame (41) are provided with a bending portion (411) away from the inner side of the liner (42) and the movable gap (9) formed between the column (21).

5. The automated high-bay warehouse according to claim 4, characterized in that: The guide sleeve (211) is filled with a reinforcing tube (213), the outer end of the reinforcing tube (213) is welded with a limiting ring (214), the limiting ring (214) is limited at the outer end of the guide sleeve (211), the inner end of the reinforcing tube (213) passes through the inner end of the guide sleeve (211) and extends to the middle of the liner (42), and the two reinforcing tubes (213) on the same side are connected by a tension spring.

6. The automated high-bay warehouse according to claim 5, characterized in that: The column (21) is a pipe, and an assembly opening (216) is opened inwardly from the pipe wall of the column (21). The locking assembly (7) comprises a guide tube (71) fixed in the pipe cavity of the column (21), a locking rod (72) perpendicular to the pipe cavity of the column (21), and a spring (73) elastically arranged between the locking rod (72) and the guide tube (71). The top end of the locking rod (72) extends from the assembly opening (216) to the bottom of the bending portion (411), and is fixed with a lifting seat (74) located below the bending portion (411) and slidably matched with the bottom surface of the bending portion (411). The locking assembly (7) also comprises an inclined seat (76) fixed on the bottom surface of the bending portion (411). The bottom end of the locking rod (72) enters the caster (6) and is installed with a locking seat (75) located above the wheel of the caster (6).

7. The automated high-bay warehouse according to claim 6, characterized in that: The locking components (7) are divided into two groups and are only arranged on two upright posts (21) on the same side as the correction plate (8).

8. The automated high-bay warehouse according to claim 7, characterized in that: The lifting seat (74) is provided with an arc-shaped groove (731) that is slidably matched with the bottom surface of the bending portion (411), and the arc-shaped groove (731) and the inclined seat (76) are on the same straight line.

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