CN217836456U - Extensible logistics freight tray - Google Patents

Abstract

The utility model discloses an extensible logistics freight pallet, which comprises a pallet and a first threaded rod. By being provided with a worm, a worm wheel, a second threaded rod, and a roller, when the device needs to be moved and operated, the circular plate on the side shell is pulled to draw the circular plate out of the circular groove, and the circular plate drives the worm to rotate through the movable rod, and the worm The meshing worm wheel rotates, and the worm wheel drives the second threaded rod to rotate, so that the second threaded rod moves downward continuously. When the circular plate rotates a certain number of times, the roller is in contact with the ground and the device can be lifted up by the roller, and then loosened. Open the circular plate, under the action of the spring, realize the positioning of the circular plate and avoid the rotation of the worm. This operation makes the roller on the other side of the shell lift the other side of the device for operation. At this time, you can push the device and The mobile operation of the device can be realized conveniently by using the rolling of the rollers, and the mobile operation is convenient. The utility model has the advantages of being extensible and easy to move.

Description

An extensible logistics freight pallet

technical field

The utility model relates to the field of logistics, in particular to the field of an extensible logistics freight pallet.

Background technique

Logistics freight pallets can be used to store, load, and move goods, and are one of the essential logistics equipment in modern logistics warehousing and freight. The size of the logistics freight pallets in the prior art is mostly fixed. In the process of actually storing the goods, it will appear that a single logistics freight pallet cannot carry the goods well because of the large volume of the goods. It greatly restricts the handling and transfer of goods in the later stage of logistics, and even leads to the dumping of goods, which greatly affects logistics and freight transportation. This is a major shortcoming of the existing technology. Technical logistics freight pallets need to use forklifts or ground cattle and other equipment for the transfer of goods, which is less flexible. For some places with relatively narrow storage locations, this will greatly affect the quality of goods. Place operation, which is another deficiency of the prior art. Based on the above reasons, the utility model proposes an extensible logistics freight pallet to solve the deficiencies of the prior art.

Utility model content

The main purpose of the utility model is to provide an extensible logistics freight pallet, which can effectively solve the problems in the background technology.

In order to achieve the above object, the technical scheme that the utility model takes is:

An extensible logistics freight pallet includes a pallet, a cavity is opened in the center of the pallet, a first threaded rod is arranged in the cavity, and the two ends of the first threaded rod are respectively connected to the cavity. The center of the front and rear side walls are flexibly connected, the front end of the first threaded rod is provided with a movable mechanism, and the side wall of the first threaded rod is evenly distributed with threaded sleeves, and the side walls of the threaded sleeves are left and right symmetrical There are two connecting plates for flexible connection, and the side of the connecting plate away from the threaded sleeve is movably connected with a movable plate, and two transverse grooves are symmetrically opened on the top surface of the supporting plate, and the movable plate and the transverse groove The left and right sides of the supporting plate are provided with side shells, and the movable plates on both sides are fixedly connected with the side shells on the side away from the connecting plate. The inner cavity of the side shell is provided with a worm, and the worm The two ends of the worm are respectively movably connected with the front and rear side walls of the inner cavity of the side shell. The front end of the worm is provided with another movable mechanism. The side walls of the worm are evenly distributed and meshed with several worm gears. The bottom surface is movably connected, the center of the side wall of the worm wheel is movably connected with a second threaded rod, the second threaded rod runs through the bottom surface of the side shell and is movably connected with a roller, the second threaded rod is threadedly connected with the bottom surface of the side shell, A plurality of support blocks are evenly distributed and fixedly connected to the bottom surface of the supporting plate, and anti-skid pads are fixedly connected to the bottom surface of the support blocks.

A further improvement of the utility model is that the movable mechanism includes a movable hole, the front ends of the first threaded rod and the worm are provided with movable holes, the inner cavity of the movable hole is fixedly connected with a spring, and the other end of the spring is fixedly connected There is a movable rod, which is flexibly connected with the movable hole, and the front side walls of the supporting plate and the side shell are provided with circular grooves, and several slots are evenly distributed on the side walls of the circular grooves , the end of the movable rod away from the spring extends out of the movable hole and is fixedly connected with a circular plate, and a plurality of inserting rods are evenly distributed and fixedly connected to the side wall of the circular plate near the movable rod, and the inserting rods are inserted into the inserting rods respectively. The groove can conveniently realize the adjustment operation of the first threaded rod and the worm, which is convenient for the use of the device.

The further improvement of the utility model is that, the side walls on both sides of the transverse groove are provided with first slide grooves, and the front and rear side walls of the movable plate are fixedly connected with first sliders, and the first sliders The flexible connection with the first chute can realize the stable movement of the movable plate in the transverse groove.

The further improvement of the utility model is that a second sliding slot is opened on the side wall of the second threaded rod, a through hole is opened in the center of the side wall of the worm wheel, and a second sliding slot is fixedly connected to the inner side wall of the through hole. block, the second threaded rod runs through the through hole, and the second sliding block is movably connected with the second chute, so as to facilitate the rotation and up-and-down movement operation of the second threaded rod through the rotation of the worm wheel.

The further improvement of the utility model is that two side grooves are symmetrically opened on the inner side wall of the movable hole, and two movable blocks are fixedly connected symmetrically on the side wall near the end of the spring of the movable rod, and the movable block The flexible connection with the side groove can facilitate the movement of the movable rod in the side groove, and can conveniently drive the first threaded rod and the worm to rotate through the movable rod.

The further improvement of the utility model is that the inner diameter of the circular groove is set larger than the diameter of the circular plate. On the one hand, it can avoid the impact of the circular plate extending out on the device, and on the other hand, it can facilitate the operation of pulling the circular plate out of the circular groove. Ease of use.

Compared with the prior art, the utility model has the following beneficial effects:

1. By setting the first threaded rod, threaded sleeve, connecting plate, movable plate and side shell, before the device stacks the goods, the device is adjusted according to the size of the goods or the quantity of the goods. By pulling the supporting plate the circular plate on the top, so that the circular plate is drawn out from the circular groove, the circular plate drives the movable rod to move in the movable hole, the spring is stretched, and then the circular plate is rotated, the circular plate drives the first threaded rod to rotate through the movable rod, and the second The rotation of a threaded rod can make the threaded sleeve move on its side wall, the threaded sleeve drives the connecting plate to move, the movable plate is pushed out through the connecting plate, the movable plate extends out of the left and right side walls of the supporting plate, and drives the side shell through the movable plate Movement, at this time, through the top surface of the pallet, the movable plate and the side shells on both sides, the size of the stacked area of the goods can be changed. When the stacked area reaches the required level, stop rotating the circular plate and release the circular plate. Under the action of the spring down, so that the movable rod drives the circular plate to move, the circular plate is retracted into the circular groove, and the insertion rod on the circular plate is inserted into the slot on the side wall of the circular groove to realize the positioning of the circular plate and avoid the first threaded rod The rotation can make the device convenient for stacking goods of different sizes and quantities, and the use effect is good.

2. By being provided with a worm, a worm wheel, a second threaded rod and a roller, when the device needs to be moved and operated, the circular plate on the side shell is pulled to draw the circular plate out of the circular groove, and the circular plate drives the movable rod in the movable hole. Internal movement, the spring is stretched, and then the circular plate is rotated, the circular plate drives the worm to rotate through the movable rod, the worm meshes with the worm wheel to rotate, the worm wheel drives the second threaded rod to rotate, and the spiral rotation between the second threaded rod and the side shell makes The second threaded rod moves downward continuously. When the circular plate rotates a certain number of times, the roller is in contact with the ground and the device can be lifted up by the roller, and then the circular plate is released. Under the action of the spring, the movable rod Drive the circular plate to move, the circular plate is retracted into the circular groove, and the insert rod on the circular plate is inserted into the slot on the side wall of the circular groove to realize the positioning of the circular plate and avoid the rotation of the worm. This operation makes the other side The roller on the shell lifts the other side of the device for operation. At this time, the device can be moved and operated conveniently by pushing the device and utilizing the rolling of the roller.

Description of drawings

Fig. 1 is a three-dimensional structural schematic diagram of an extensible logistics freight pallet of the present invention.

Fig. 2 is a schematic diagram of the internal structure of an extensible logistics freight pallet of the present invention.

Fig. 3 is a schematic structural diagram of A-A plane of Fig. 2 in an extensible logistics freight pallet of the present invention.

Fig. 4 is an enlarged view of B in Fig. 2 in an extensible logistics freight pallet of the present invention.

Fig. 5 is an enlarged view of C in Fig. 3 in an extensible logistics freight pallet of the present invention.

In the figure: 1, supporting plate; 2, first threaded rod; 3, movable mechanism; 4, threaded sleeve; 5, connecting plate; 6, movable plate; 7, side shell; 8, worm; 9, worm gear; 10, The second threaded rod; 11, roller; 12, movable hole; 13, spring; 14, movable rod; 15, round groove; 16, slot; 17, circular plate; 20. The first slider; 21. The second chute; 22. The second slider; 23. The side groove; 24. The movable block; 25. The support block; 26. The anti-skid pad.

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the utility model easy to understand, in the description of the utility model, it should be noted that the terms "center", "upper", "lower" and "left" , "right", "vertical", "horizontal", "inner", "outer" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the utility model and simplifying the Describes, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the present invention. In addition, the terms "number one", "number two", and "number three" are used for descriptive purposes only, and should not be understood as indicating or implying relative importance. Below in conjunction with specific embodiment, further elaborate the utility model.

Example 1

As shown in Figure 1-5, an extensible logistics freight pallet includes a pallet 1, a cavity is opened in the center of the pallet 1, a first threaded rod 2 is arranged in the cavity, and the two ends of the first threaded rod 2 The ends are respectively movably connected with the center of the front and rear side walls of the cavity, the front end of the first threaded rod 2 is provided with a movable mechanism 3, the movable mechanism 3 includes a movable hole 12, and the front ends of the first threaded rod 2 and the worm 8 are provided with a movable hole 12 , the cavity of the movable hole 12 is fixedly connected with a spring 13, and the other end of the spring 13 is fixedly connected with a movable rod 14, and the movable rod 14 is connected with the movable hole 12, and the inner wall of the movable hole 12 is symmetrically provided with two side grooves. 23. Two movable blocks 24 are fixedly connected symmetrically to the left and right on the side wall near one end of the spring 13. The movable block 24 is flexibly connected to the side groove 23, and the front side walls of the supporting plate 1 and the side shell 7 are provided with There is a circular groove 15, and several slots 16 are evenly distributed on the side wall of the circular groove 15. The movable rod 14 extends out of the movable hole 12 away from the end of the spring 13 and is fixedly connected with a circular plate 17. The inner diameter of the circular groove 15 is larger than that of the circular plate. The diameter of 17 is set, and on the side wall of circular plate 17 near movable bar 14 side walls, uniform distribution is fixedly connected with several inserting rods 18, and inserting rods 18 insert slots 16 respectively, evenly distributed on the side wall of the first threaded rod 2 There are several threaded sleeves 4 in the threaded connection, and two connecting plates 5 are movably connected symmetrically left and right on the side walls of the threaded sleeves 4, and the side walls of the connecting plates 5 away from the threaded sleeves 4 are movably connected with a movable plate 6, and the top surface of the supporting plate 1 There are two transverse grooves symmetrically opened on the left and right, and the movable plate 6 is flexibly connected with the transverse grooves. The first chute 19 is provided on the side walls of both sides of the transverse groove, and the front and rear side walls of the movable plate 6 are all fixed. The first slider 20 is connected, and the first slider 20 is flexibly connected with the first chute 19. The left and right sides of the supporting plate 1 are provided with side shells 7, and the movable plates 6 on both sides are away from the connecting plate 5, respectively. It is fixedly connected with the side shell 7 , and several support blocks 25 are evenly distributed and fixedly connected to the bottom surface of the supporting plate 1 , and the bottom surface of the support block 25 is fixedly connected with an anti-skid pad 26 .

It can be realized by this embodiment: by being provided with the first threaded rod 2, the threaded sleeve 4, the connecting plate 5, the movable plate 6 and the side shell 7, before the device stacks the goods, according to the size of the goods or the quantity of the goods, To adjust the device, the circular plate 17 is drawn out from the circular groove 15 by pulling the circular plate 17 on the supporting plate 1, the circular plate 17 drives the movable rod 14 to move in the movable hole 12, the spring 13 is stretched, and then the The circular plate 17 rotates, and the circular plate 17 drives the first threaded rod 2 to rotate through the movable rod 14. The rotation of the first threaded rod 2 can make the threaded sleeve 4 move on its side wall, and the threaded sleeve 4 drives the connecting plate 5 to move. The connecting plate 5 pushes out the movable plate 6, and the movable plate 6 extends out of the left and right side walls of the supporting plate 1, and drives the side shell 7 to move through the movable plate 6. The side shell 7 can change the size of the area where the goods are stacked. When the area of stacking reaches the need, the circular plate 17 is stopped to rotate, and the circular plate 17 is released. Under the action of the spring 13, the movable rod 14 drives the circular plate 17 to move. The circular plate 17 is retracted into the circular groove 15, and the insertion rod 18 on the circular plate 17 is inserted into the slot 16 on the side wall of the circular groove 15, so as to realize the positioning of the circular plate 17 and avoid the rotation of the first threaded rod 2, The device can facilitate stacking operations for goods of different sizes and quantities, and has a good use effect.

Example 2

As shown in Figure 1-5, an extensible logistics freight pallet includes a pallet 1, a cavity is opened in the center of the pallet 1, a first threaded rod 2 is arranged in the cavity, and the two ends of the first threaded rod 2 The ends are respectively movably connected with the center of the front and rear side walls of the cavity, and the front end of the first threaded rod 2 is provided with a movable mechanism 3, and the side walls of the first threaded rod 2 are evenly distributed and threaded and connected with several threaded sleeves 4. On the side wall, there are two connecting plates 5 which are movable connected symmetrically left and right. The connecting plate 5 is connected with movable plates 6 on one side away from the threaded sleeve 4. The top surface of the supporting plate 1 is symmetrically provided with two transverse grooves. The plate 6 is movably connected with the transverse groove, and the sidewalls on both sides of the transverse groove are provided with the first chute 19, and the front and rear sidewalls of the movable plate 6 are fixedly connected with the first slider 20, the first slider 20 It is movably connected with the first chute 19, and the left and right sides of the supporting plate 1 are provided with side shells 7, and the side of the movable plate 6 on both sides away from the connecting plate 5 is fixedly connected with the side shell 7 respectively, and the inner cavity of the side shell 7 is set There is a worm 8, and the two ends of the worm 8 are respectively movably connected with the front and rear side walls of the side shell 7, and the front end of the worm 8 is provided with another movable mechanism 3, the movable mechanism 3 includes a movable hole 12, the first threaded rod 2 and the worm 8 The front ends of each are provided with movable holes 12, and the inner cavity of the movable holes 12 is fixedly connected with a spring 13, and the other end of the spring 13 is fixedly connected with a movable rod 14, which is flexibly connected between the movable rod 14 and the movable hole 12, and on the inner side wall of the movable hole 12 There are two side grooves 23 symmetrically arranged on the left and right, and two movable blocks 24 are fixedly connected symmetrically on the side wall near the end of the spring 13 on the movable rod 14. The movable block 24 is flexibly connected to the side grooves 23. 7 are provided with circular grooves 15 on the front side walls of the circular grooves 15, and several slots 16 are evenly distributed on the side walls of the circular grooves 15. The movable rod 14 extends out of the movable hole 12 away from the end of the spring 13 and is fixedly connected with a circular plate 17. The inner diameter of circular groove 15 is greater than the diameter setting of circular plate 17, and on the side wall of circular plate 17 near movable bar 14 sides, uniform distribution is fixedly connected with several inserting rods 18, and inserting rods 18 insert slot 16 respectively, and worm screw 8 Several worm gears 9 are evenly distributed and meshed on the side wall, and the worm gear 9 is movably connected with the bottom surface of the inner cavity of the side shell 7. The center of the side wall of the worm gear 9 is movably connected with a second threaded rod 10, and the side wall of the second threaded rod 10 is provided with a The second chute 21 has a through hole at the center of the side wall of the worm wheel 9, the inner side wall of the through hole is fixedly connected with the second slide block 22, the second threaded rod 10 runs through the through hole, the second slide block 22 and the second chute 21 are movably connected, the second threaded rod 10 runs through the bottom surface of the side shell 7 and is movably connected with a roller 11, the second threaded rod 10 is threadedly connected with the bottom surface of the side shell 7, and the bottom surface of the supporting plate 1 is evenly distributed and fixedly connected with several A support block 25, the bottom surface of the support block 25 is fixedly connected with a non-slip pad 26.

Can realize by this embodiment: by being provided with worm screw 8, worm wheel 9, second threaded rod 10 and roller 11, when needing this device is moved and operated, by pulling the disc 17 on the side shell 7, make disc 17 from circle Draw out in the slot 15, the circular plate 17 drives the movable rod 14 to move in the movable hole 12, the spring 13 is stretched, and then the circular plate 17 is rotated, the circular plate 17 drives the worm 8 to rotate through the movable rod 14, and the worm 8 meshes with the worm gear 9 Turn, the worm wheel 9 drives the second threaded rod 10 to rotate, and the spiral rotation between the second threaded rod 10 and the side shell 7 makes the second threaded rod 10 move downward continuously. After the circular plate 17 rotates a certain number of times, at this time The roller 11 is in contact with the ground and the device can be jacked up by the roller 11, and then the circular plate 17 is released, and under the action of the spring 13, the movable rod 14 drives the circular plate 17 to move, and the circular plate 17 is retracted into the circular groove 15, And the insert rod 18 on the circular plate 17 is inserted in the slot 16 on the side wall of the circular groove 15 to realize the positioning of the circular plate 17 and avoid the rotation of the worm screw 8, so that the roller 11 on the other side shell 7 will The other side of the device is jacked up for operation. At this time, the device can be easily moved by pushing the device and utilizing the rolling of the roller 11, and the operation is convenient.

It should be noted that the utility model is an extensible logistics freight pallet. Before the device stacks the goods, the device is adjusted according to the size of the goods or the quantity of the goods. By pulling the circle on the pallet 1 plate 17, so that the circular plate 17 is extracted from the circular groove 15, the circular plate 17 drives the movable rod 14 to move in the movable hole 12, the spring 13 is stretched, and then the circular plate 17 is rotated, and the circular plate 17 is driven by the movable rod 14 The first threaded rod 2 rotates, the rotation of the first threaded rod 2 can make the threaded sleeve 4 move on its side wall, the threaded sleeve 4 drives the connecting plate 5 to move, the movable plate 6 is pushed out through the connecting plate 5, and the movable plate 6 extends The left and right side walls of the pallet 1 are removed, and the side shell 7 is driven by the movable plate 6 to move. At this time, the area of the goods stacked can be changed through the top surface of the pallet 1, the movable plate 6 and the side shells 7 on both sides. Stop rotating the circular plate 17 after the area reaches the requirement, and unclamp the circular plate 17, under the action of the spring 13, the movable rod 14 drives the circular plate 17 to move, the circular plate 17 is retracted in the circular groove 15, and the circular plate 17 The insertion rod 18 on the top is inserted into the slot 16 on the side wall of the circular groove 15 to realize the positioning of the circular plate 17 and avoid the rotation of the first threaded rod 2, which can make the device convenient for stacking goods of different sizes and quantities Operation, the use effect is good, after the goods are stacked, when the device needs to be moved, the circular plate 17 on the side shell 7 is pulled, so that the circular plate 17 is drawn out from the circular groove 15, and the circular plate 17 drives the movable rod 14 to move Movement in the hole 12, the spring 13 is stretched, and then the circular plate 17 is rotated, the circular plate 17 drives the worm 8 to rotate through the movable rod 14, the worm 8 meshes with the worm wheel 9 to rotate, and the worm wheel 9 drives the second threaded rod 10 to rotate, the second The spiral rotation between the threaded rod 10 and the side shell 7 makes the second threaded rod 10 continuously move downwards. When the circular plate 17 rotates a certain number of times, the roller 11 is in contact with the ground and the device can be pushed up by the roller 11. Then release the circular plate 17, under the action of the spring 13, the movable rod 14 drives the circular plate 17 to move, the circular plate 17 is retracted into the circular groove 15, and the insertion rod 18 on the circular plate 17 is inserted into the circular groove 15 In the slot 16 on the side wall, the positioning of the circular plate 17 is realized to avoid the rotation of the worm 8. This operation makes the roller 11 on the other side shell 7 lift up the other side of the device. The device also utilizes the rolling of the roller 11 to conveniently realize the mobile operation of the device, and the mobile operation is convenient.

The basic principles and main features of the present utility model and the advantages of the present utility model have been shown and described above. Those skilled in the industry should understand that the utility model is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model The new model also has various changes and improvements, and these changes and improvements all fall within the scope of the claimed utility model. The scope of protection required by the utility model is defined by the appended claims and their equivalents.

Claims (6)

1. An extensible logistics freight pallet, comprising a pallet (1), characterized in that: a cavity is opened in the center of the pallet (1), and a first threaded rod (2) is arranged in the cavity , the two ends of the first threaded rod (2) are respectively movably connected with the center of the front and rear side walls of the cavity, the front end of the first threaded rod (2) is provided with a movable mechanism (3), and the first threaded rod There are several threaded sleeves (4) evenly distributed on the side wall of (2), and there are two connecting plates (5) on the side wall of the threaded sleeve (4), which are symmetrically connected left and right, and the connecting plates (5) ) is movably connected with a movable plate (6) on the side far away from the threaded sleeve (4). The grooves are flexibly connected, and the left and right sides of the supporting plate (1) are provided with side shells (7), and the movable plates (6) on both sides are respectively connected to the side shells (7) on the side away from the connecting plate (5). Fixed connection, the inner cavity of the side shell (7) is provided with a worm (8), the two ends of the worm (8) are respectively connected with the front and rear side walls of the inner cavity of the side shell (7), and the worm (8) Another movable mechanism (3) is provided at the front end, and several worm gears (9) are evenly distributed and meshed on the side wall of the worm (8), and the worm gear (9) is movably connected with the bottom surface of the inner cavity of the side shell (7). The center of the side wall of the worm wheel (9) is movably connected with a second threaded rod (10), and the second threaded rod (10) penetrates the bottom surface of the side shell (7) and is movably connected with a roller (11). The threaded rod (10) is threadedly connected to the bottom surface of the side shell (7), and several support blocks (25) are uniformly distributed and fixedly connected to the bottom surface of the support plate (1), and the bottom surface of the support block (25) Fixedly connected with non-slip pad (26). 2. An extensible logistics freight pallet according to claim 1, characterized in that: the movable mechanism (3) includes a movable hole (12), the first threaded rod (2) and the worm (8) The front ends of each are provided with a movable hole (12), and the inner cavity of the movable hole (12) is fixedly connected with a spring (13), and the other end of the spring (13) is fixedly connected with a movable rod (14), and the movable rod ( 14) Flexible connection with the movable hole (12), the front side wall of the supporting plate (1) and the side shell (7) are provided with a round groove (15), the side wall of the round groove (15) Several slots (16) are evenly distributed on the top, and the movable rod (14) extends out of the movable hole (12) away from the end of the spring (13) and is fixedly connected with a circular plate (17). The circular plate (17) A plurality of inserting rods (18) are evenly distributed and fixedly connected to the side wall near the movable rod (14), and the inserting rods (18) are respectively inserted into the slots (16). 3. An extensible logistics freight pallet according to claim 1, characterized in that: the first chute (19) is opened on both side walls of the horizontal groove, and the movable plate (6) A first slider (20) is fixedly connected to the front and rear side walls of the first slider (20), and the first slider (20) is flexibly connected to the first chute (19). 4. The extensible logistics freight pallet according to claim 1, characterized in that: a second chute (21) is opened on the side wall of the second threaded rod (10), and the worm wheel (9 ) has a through hole in the center of the side wall, the second slider (22) is fixedly connected to the inner wall of the through hole, the second threaded rod (10) runs through the through hole, and the second slider (22) It is flexibly connected with the second chute (21). 5. An extensible logistics freight pallet according to claim 2, characterized in that: two side grooves (23) are symmetrically opened on the inner wall of the movable hole (12), and the movable rod ( 14) There are two movable blocks (24) symmetrically fixedly connected to the side wall near one end of the spring (13), and the movable blocks (24) are movably connected to the side groove (23). 6. The extensible logistics freight pallet according to claim 2, characterized in that: the inner diameter of the circular groove (15) is set larger than the diameter of the circular plate (17).

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