CN113926908A

CN113926908A - Pole piece die-cutting machine for lithium ion battery production line

Info

Publication number: CN113926908A
Application number: CN202111271327.9A
Authority: CN
Inventors: 刘士斌; 张云龙; 董亭亭; 许健伟; 王静
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2022-01-14

Abstract

The invention discloses a pole piece die-cutting machine for a lithium ion battery production line, which comprises a coil stock discharging assembly and a fixed shell, wherein a die-cutting assembly is arranged in the fixed shell, the die-cutting assembly comprises a sliding block and a base which are sequentially arranged from top to bottom, a placing groove is formed in the middle of the base, a cutting die is arranged at the edge of a notch of the placing groove, and a cutter groove matched with the cutting die is formed in the lower surface of the sliding block. According to the pole piece die-cutting machine for the lithium ion battery production line, the cutting die is arranged below the cutter groove, and the placing groove for containing the cut pole piece is arranged below the cutting die, namely, the cutting die is inserted into the cutter groove through the sliding block moving in the direction of the cutting die during cutting, the pole piece is cut, and then the pole piece falls into the placing groove under the extrusion of the sliding block, so that the pole piece is separated from a coil stock without manual operation, the pole piece can be completely peeled, the labor cost is greatly reduced, and the production efficiency of the lithium ion battery is improved.

Description

Pole piece die-cutting machine for lithium ion battery production line

Technical Field

The invention relates to the technical field of battery production, in particular to a pole piece die-cutting machine for a lithium ion battery production line.

Background

When the lithium ion battery is produced, a plurality of coiled materials are required to be cut according to the processing size by using die cutting equipment so as to facilitate the subsequent production of the lithium ion battery;

the shortcoming of prior art lies in, when specifically carrying out the cross cutting, all continue to cut on the coil stock through the cutting die up-and-down motion, because after cutting, the pole piece is most still blocked on the pole piece is rolled up, perhaps blocks on the cutting die, needs to separate it through manual work on the production line by hand, then puts neatly, and production efficiency is lower, the pole piece of being not convenient for put, the lithium ion battery's of being more inconvenient production.

Disclosure of Invention

The invention aims to provide a pole piece die-cutting machine for a lithium ion battery production line, which aims to overcome the defects in the prior art.

In order to achieve the above purpose, the invention provides the following technical scheme:

a pole piece die-cutting machine for a lithium ion battery production line comprises a coil stock discharging assembly and a fixed shell, wherein a die-cutting assembly is arranged in the fixed shell, the die-cutting assembly comprises a sliding block and a base which are sequentially arranged from top to bottom, a placing groove is formed in the middle of the base, a cutting die is arranged at the edge of a notch of the placing groove, and a cutter groove matched with the cutting die is formed in the lower surface of the sliding block;

when cutting, the sliding block is driven by the driving mechanism to move towards the cutting die, so that the cutting die enters the cutter groove to cut the coil, and the cut pole piece falls into the placing groove.

Preferably, the caliber of the notch of the placing groove is larger than that of the notch of the cutting die, the convex edge is arranged in the cutter groove and matched with the notch of the cutter groove, and particularly, the caliber of the notch of the placing groove is larger than that of the notch of the cutting die, so that the cut pole piece is smaller than the notch of the placing groove, and the pole piece can smoothly drop downwards.

Preferably, the driving mechanism comprises a driving motor arranged on the fixed shell and an eccentric shaft arranged on an output shaft of the driving motor, and the eccentric shaft is connected to the sliding block through a transmission shaft in a transmission manner.

Preferably, the device further comprises a supporting component fixedly arranged in the base, wherein the supporting component is used for supporting the pole piece and conveying the pole piece to the bottom of the placing groove; in order to avoid scattering at the bottom of the placing groove when the pole pieces are conveyed into the placing groove after being cut, the cut pole pieces can be supported and conveyed into the placing groove through the arranged supporting assembly, the pole pieces are prevented from scattering on the bearing platform, the cut pole pieces can be orderly stacked on the bearing platform, the space in the placing groove is reasonably utilized, and the production of the subsequent lithium-ion battery is more convenient.

Preferably, the supporting component comprises a supporting ring vertically and slidably arranged in the placing groove, and a supporting rod rotatably arranged on the supporting ring, and the supporting rod is used for supporting the pole piece.

Preferably, the support ring is further provided with magnets in one-to-one correspondence with the support rods, and when the magnets are adsorbed to the support rods, the support rods lose support for the pole pieces, so that the pole pieces are laid at the bottom ends where the pole pieces are placed.

Preferably, a plurality of locking assemblies used for locking the bearing assembly are arranged on the outer side wall of the support ring, and fixing rods corresponding to the locking assemblies one to one are fixedly arranged in the base.

Preferably, the locking assembly comprises a fixed block which is slidably sleeved on the fixed rod, a locking block is slidably arranged in the fixed block, a second elastic piece is arranged between the locking block and the fixed block, and the locking block protrudes out of the fixed block due to the elastic force of the second elastic piece; the locking subassembly can carry out up-and-down motion along the mounting through the setting of fixed block, can drive the motion of bearing subassembly promptly, carries the pole piece.

Preferably, the base is provided with a plurality of stabilizing columns and a first elastic piece sleeved on the stabilizing columns, and when the cutting is performed, the sliding block is contracted into the base and extrudes the locking block, so that the fixing block slides downwards along the fixing rod under the elasticity of the elastic rope.

Preferably, telescopic rods in one-to-one correspondence to the fixing rods are arranged inside the fixing shell, and telescopic ends of the telescopic rods are sleeved on the fixing rods.

In the technical scheme, the pole piece die-cutting machine for the lithium ion battery production line provided by the invention has the following beneficial effects:

according to the invention, the cutting die for cutting the pole piece is arranged below the cutter groove, and the placing groove for containing the cut pole piece is arranged below the cutting die, namely, the sliding block is driven by the driving mechanism to move along the direction of the cutting die during cutting, so that the cutting die is inserted into the cutter groove to cut the pole piece, and then the pole piece falls into the placing groove under the extrusion of the sliding block, namely, the pole piece is not required to be manually separated from a coil stock, the pole piece can be completely peeled off, and the pole piece can be placed in the placing groove arranged in the middle of the base, so that the labor cost is greatly reduced, and the production efficiency of the lithium ion battery is improved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

This document provides an overview of various implementations or examples of the technology described in this disclosure, and is not a comprehensive disclosure of the full scope or all features of the disclosed technology.

Drawings

In order to more clearly illustrate the embodiments of the present application or technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present invention, and other drawings can be obtained by those skilled in the art according to the drawings.

FIG. 1 is a schematic structural diagram provided in an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of a fixing housing according to an embodiment of the present invention;

FIG. 3 is an enlarged schematic view of a portion A according to an embodiment of the present invention;

FIG. 4 is an enlarged schematic view of a structure at B according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a base and a support ring according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a base and a cutting die according to an embodiment of the present invention;

FIG. 7 is a schematic view of a support assembly according to an embodiment of the present invention;

FIG. 8 is a schematic cross-sectional view of a locking mechanism according to an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of a support ring and a brace bar according to an embodiment of the present invention;

FIG. 10 is a cross-sectional view of a support ring and a brace bar according to an embodiment of the present invention;

fig. 11 is a schematic structural view of a support ring and a stay bar when the stay bar is attached to a magnet according to an embodiment of the present invention;

fig. 12 is a schematic structural diagram of a sliding block, a knife slot, and a transmission shaft according to an embodiment of the present invention.

Description of reference numerals:

1. a support frame; 2. a stationary case; 3. a support pillar; 111. a guide wheel; 21. a drive motor; 31. coiling; 211. an eccentric shaft; 311. pole pieces; 4. a base; 41. a stabilization post; 401. a placement groove; 411. a first elastic member; 42. fixing the rod; 421. a telescopic rod; 43. cutting the die; 44. a bearing block; 5. a support ring; 502. Inserting grooves; 51. a fixed block; 511. a locking block; 5111. a second elastic member; 512. an elastic cord; 52. A stay bar; 521. a magnet; 6. a slider; 61. a drive shaft; 62. a rib; 601. a cutter groove; 7. a pinch roller; 8. and (5) shifting blocks.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the technical solutions of the embodiments of the present disclosure will be described clearly and completely with reference to the drawings of the embodiments of the present disclosure. It is to be understood that the described embodiments are only a few embodiments of the present disclosure, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the disclosure without any inventive step, are within the scope of protection of the disclosure.

Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The use of the word "comprising" or "comprises", and the like, in this disclosure is intended to mean that the elements or items listed before that word, include the elements or items listed after that word, and their equivalents, without excluding other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may also include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

Referring to fig. 1-12, a pole piece die-cutting machine for a lithium ion battery production line comprises a coil stock 31 discharging assembly and a fixed shell 2, wherein a die-cutting assembly is arranged in the fixed shell 2, the die-cutting assembly comprises a sliding block 6 and a base 4 which are sequentially arranged from top to bottom, a placing groove 401 is formed in the middle of the base 4, a cutting die 43 is arranged at the edge of a notch of the placing groove 401, and a knife groove 601 matched with the cutting die 43 is formed in the lower surface of the sliding block 6; at the time of cutting, the slide block 6 is driven by the driving mechanism to move toward the cutter die 43, so that the cutter die 43 enters the cutter groove 601 to cut the roll material 31, and the cut pole piece 311 falls into the placing groove 401.

Specifically, the coil 31 discharging component comprises a supporting column 3 and a coil 31 fixedly arranged on the supporting frame 1, the coil 31 is arranged on the supporting column 3 and then driven to rotate by a motor, one end of a transmission shaft 61 is rotationally connected to an eccentric shaft 211, the other end of the transmission shaft 61 is rotationally connected to a sliding block 6, namely when the driving motor 21 drives the eccentric shaft 211 to rotate, the sliding block 6 can be driven to vertically reciprocate by the transmission shaft 61, the coil 31 is conveyed between the sliding block 6 and a base 4, then when cutting, the sliding block 6 moves towards a cutting die 43, so that the cutting die 43 is inserted into the matched cutting die 43, the coil 31 is cut, the cutting die 43 is customized according to the shape and the size of the pole piece 311, namely, the cut coil 31 forms the pole piece 311 and then falls into the placing groove 401, the bottom end of the placing groove 401 is provided with a bearing block 44, the cut pole piece 311 is placed on the bearing block 44, namely, in the invention, the cutting die 43 for cutting the pole piece 311 is arranged below the cutter groove 601, and the placing groove 401 for containing the cut pole piece 311 is arranged below the cutting die 43, that is, when cutting is performed, the sliding block 6 is driven by the driving mechanism to move in the direction of the cutting die 43, so that the cutting die 43 is inserted into the cutter groove 601 to cut the pole piece 311, and then the pole piece 311 drops into the placing groove 401 under the extrusion of the sliding block 6, that is, the pole piece 311 does not need to be manually separated from the coil stock 31, the pole piece 311 can be completely peeled off, and can be placed in the placing groove 401 arranged in the middle of the base 4, so that the labor cost is greatly reduced, and the production efficiency of the lithium ion battery is improved.

In a further embodiment of the present invention, the aperture of the notch of the placement groove 401 is larger than the aperture of the notch of the cutting die 43, the inside of the cutting groove 601 is provided with the protruding rib 62, and the protruding rib 62 is matched with the notch of the cutting groove 601, specifically, the aperture of the notch of the placement groove 401 is larger than the aperture of the notch of the cutting die 43, so that the cut pole piece 311 is smaller than the notch of the placement groove 401, i.e., can smoothly drop downward.

Further, the driving mechanism includes a driving motor 21 disposed on the fixed casing 2 and an eccentric shaft 211 disposed on an output shaft of the driving motor 21, and the eccentric shaft 211 is drivingly connected to the sliding block 6 through a transmission shaft 61.

Further, the invention also comprises a supporting component fixedly arranged in the base 4, the supporting component is used for supporting the pole piece 311 and conveying the pole piece 311 to the bottom of the placing groove 401, the supporting component comprises a supporting ring 5 vertically and slidably arranged in the placing groove 401 and a supporting rod 52 rotatably arranged on the supporting ring 5, the supporting rod 52 is used for supporting the pole piece 311, more preferably, in the invention, in order to avoid the pole piece 311 scattering at the bottom of the placing groove 401 after being cut and conveyed into the placing groove 401, in the invention, the cut pole piece 311 can be supported and conveyed into the placing groove 401 through the supporting component, the pole piece 311 is prevented from scattering on the bearing table, the cut pole piece 311 can be neatly stacked on the bearing table, the space in the placing groove 401 can be reasonably utilized, the production of the subsequent lithium-ion battery is more convenient, and the production efficiency of the production line is further improved, specifically, the stay 52 is used for supporting the pole piece 311, and then under the movement of the support ring 5, the pole piece 311 can be driven to synchronously move to the lower side, and then the pole piece is placed on the bearing block 44.

Further, the support ring 5 is further provided with magnets 521 corresponding to the support rods 52 one by one, when the magnets 521 and the support rods 52 are attracted, the support rods 52 lose support of the pole pieces 311, so that the pole pieces 311 are laid at the bottom end where the pole pieces are placed, specifically, the support rods 52 are further provided with magnets 521 corresponding to the number and the positions of the support rods 52, when the magnets 521 and the support rods 52 are attracted, as shown in the state of fig. 10, the support rods 52 can support the pole pieces 311 at this time, the support rods 52 lose support of the pole pieces 311, and then the pole pieces 311 fall on the bearing table.

Further, be provided with a plurality of locking subassemblies that are used for locking bearing subassembly on support ring 5's the lateral wall, 4 internal fixation of base is provided with the dead lever 42 with locking subassembly one-to-one, the locking subassembly includes that the slip cover establishes fixed block 51 on dead lever 42, it is provided with locking piece 511 to slide on being provided with in the fixed block 51, be provided with second elastic component 5111 between locking piece 511 and the fixed block 51, the elasticity of second elastic component 5111 makes locking piece 511 protrusion to fixed block 51, the locking subassembly can carry out reciprocating motion from top to bottom along the mounting through fixed block 51's setting, can drive the bearing subassembly motion promptly, carry pole piece 311.

Further, the base 4 is provided with a plurality of stabilizing posts 41 and a first elastic member 411 sleeved on the stabilizing posts 41, when cutting is performed, the sliding block 6 is retracted into the base 4, the locking block 511 is extruded, so that the fixing block 51 slides downwards along the fixing rod 42 under the elastic force of the elastic rope 512, the fixing shell 2 is internally provided with telescopic rods 421 corresponding to the fixing rod 42 one by one, and the telescopic ends of the telescopic rods 421 are sleeved on the fixing rod 42, the invention can enable the supporting component to move downwards after receiving the cut pole piece 311 through the arranged locking component, and after continuous production, the height of the pole piece 311 overlapped on the placing groove 401 is gradually increased, and the normal operation of the device can be still ensured under the condition that the overlapping height of the pole piece 311 on the supporting block 44 is continuously changed due to the cooperation of the locking component, the supporting rod 52, the elastic rope 512 and the telescopic rod 421 provided in the embodiment, corresponding control programs can be saved, equipment cost is reduced, and the pole pieces 311 can still be neatly stacked.

According to the invention, the supporting component for supporting the cut pole piece 311 is arranged in the base 4, namely the pole piece 311 can be supported, and then the pole piece 311 can be conveyed downwards to the lower part of the placing groove 401 through the arrangement of the elastic rope 512 and the locking component, so that the condition that the pole piece 311 falls disorderly due to irregular overturning during falling can be avoided, namely, the cut pole piece 311 can be neatly stacked on the supporting platform, the space in the placing groove 401 can be reasonably utilized, the subsequent production of lithium-ion batteries is more convenient, and the production efficiency of a production line is further improved.

When the cutting machine is used for cutting, then, the winding tapes of the winding materials 31 are wound on the guide wheels inside the base 4 one by one according to requirements, then, one end of the winding tape penetrates through the space between the sliding block 6 and the base 4, then, the winding tape penetrates through the space between the two pressing wheels 7 and the two guide wheels 111, firstly, the device is started, then, the motor for driving the winding materials 31 to rotate and the control guide wheels 111 are used for controlling the guide wheels 111 to start rotating, then, the winding materials 31 start to be conveyed in the fixed shell 2, when the winding materials are conveyed to the base 4, the conveying motor stops conveying, at the moment, the driving motor 21 for controlling the eccentric shaft 211 to rotate rotates for one circle to drive the eccentric shaft 211 to rotate, namely, the sliding block 6 is driven to reciprocate in the vertical direction through the transmission of the transmission shaft 61, and then, when the sliding block 6 moves downwards, the winding tapes are gradually pressed downwards in the downward movement process: so that the cutting die 43 on the base 4 is gradually inserted into the knife slot 601 formed below the sliding block 6, that is, the tape is cut while being inserted, after cutting, the rib 62 is located below the cutting die 43, that is, the pole piece 311 which has been cut off drops on the stay 52, the stabilizing post 41 is slidably arranged above the base 4, the stabilizing post 41 is arranged to not only pre-fix the tape and facilitate the cutting of the cutting die 43, but also serve as an unlocking structure of the locking assembly, so that after cutting, the locking block 511 can be pressed by the stabilizing post 41 and then the support ring 5 is triggered to move downwards, the pole piece 311 is conveyed to the bottom end of the placing groove 401 to gradually abut against the tape, the top of the stabilizing post 41 is provided with a buffer pad for protecting the tape from abrasion of the stabilizing post 41, the stabilizing post 41 abuts against the tape, that is, the lower surface of the sliding block 6, while continuing to move downward, the pressing stabilization posts 41 are gradually retracted into the base 4, and when the sliding posts are moved to the set lowest position, the stabilization posts 41 are also moved to the lowest position, and then presses the locking piece 511 caught in the groove in which the stabilizing post 41 is located, so that the locking piece 511 is released from the groove, that is, the fixing block 51 and the supporting block are not locked by the locking block 511 any more, and then, under the elastic force of the elastic cord 512, the supporting ring 5 is moved downward, i.e. the pole piece 311 to be held on the stay 52, moves downwards in synchronism, and when moving downwards to the lowest position, the stay 52 is instantaneously moved downward due to the elastic force of the elastic string 512, and then the stay 52 is rotated to the inside of the base 4 along the axis hinged to the base 4 under the pressing of the lower bearing block 44, the pole piece 311 is not supported by the support rod 52, that is, the pole piece 311 can fall on the bearing block 44; the driving motor 21 drives the eccentric shaft 211 to rotate for a circle, so that the sliding block 6 returns to the initial position after moving downward for a distance, and the stable column 41 is not pressed downward by the sliding block 6, and moves upward under the elastic force of the first elastic member 411, then the telescopic rod 421 moves, so that the telescopic rod 421 moves upward, and then the fixed block 51 sleeved on the fixed rod 42 is pushed to move upward, so as to drive the fixed rod 42 to move to the initial position, so that the locking block 511 slidably arranged on the fixed rod 42 is again clamped in the groove where the stable column 41 is located, the locking block 511 is provided with a round corner, so that the locking block 511 is pushed by the telescopic rod 421 to compress the second elastic member 5111, and then enters the groove where the stable column 41 is located, so that the support ring 5 and the brace 52 move upward synchronously at the initial position, and while moving upward, the corresponding position above each brace 52 is provided with a head shifting block 8, the shifting block 8 is fixedly arranged below the cutting die 43, in the upward movement process of the support ring 5, the shifting block 8 moves relative to the support ring 5, the shifting block 8 is inserted into the insertion groove 502, when the shifting block is inserted into the insertion groove 502, the shifting block is inserted between the magnet 521 and the stay bar 52, the stay bar 52 is separated from the magnet 521, the shifting block 8 is made of a non-metal material and is not adsorbed to the magnet 521, namely, when the glass magnet 521 and the stay bar 52 are arranged, the stay bar 52 returns to the initial position and is in the stretched position, and at the moment, the support pole piece 311 can be supported again.

While certain exemplary embodiments of the present invention have been described above by way of illustration only, it will be apparent to those of ordinary skill in the art that the described embodiments may be modified in various different ways without departing from the spirit and scope of the invention. Accordingly, the drawings and description are illustrative in nature and should not be construed as limiting the scope of the invention.

Claims

1. The utility model provides a pole piece cross cutting machine that lithium ion battery production line was used, includes coil stock (31) blowing subassembly and set casing (2), its characterized in that: a die cutting assembly is arranged in the fixed shell (2), the die cutting assembly comprises a sliding block (6) and a base (4) which are sequentially arranged from top to bottom, a placing groove (401) is formed in the middle of the base (4), a cutting die (43) is arranged at the edge of a notch of the placing groove (401), and a knife groove (601) matched with the cutting die (43) is formed in the lower surface of the sliding block (6);

during cutting, the sliding block (6) is driven by a driving mechanism to move towards a cutting die (43), so that the cutting die (43) enters the cutter groove (601) to cut the coil (31), and the cut pole piece (311) falls into the placing groove (401).

2. The pole piece die cutting machine for the lithium ion battery production line is characterized in that the notch aperture of the placing groove (401) is larger than the notch aperture of the cutting die (43), a convex rib (62) is arranged inside the cutter groove (601), and the convex rib (62) is matched with the notch of the cutter groove (601).

3. The pole piece die cutting machine for the lithium ion battery production line according to claim 1, wherein the driving mechanism comprises a driving motor (21) arranged on the fixed shell (2) and an eccentric shaft (211) arranged on an output shaft of the driving motor (21), and the eccentric shaft (211) is in transmission connection with the sliding block (6) through a transmission shaft (61).

4. The die cutting machine for the pole pieces used in the lithium ion battery production line according to claim 1, further comprising a supporting component fixedly arranged in the base (4), wherein the supporting component is used for supporting the pole pieces (311) and transporting the pole pieces (311) to the bottom of the placing groove (401).

5. The die cutting machine for pole pieces in the production line of lithium ion batteries according to claim 4, characterized in that the supporting component comprises a supporting ring (5) vertically slidably arranged in the placing groove (401), and a supporting rod (52) rotatably arranged on the supporting ring (5), wherein the supporting rod (52) is used for supporting the pole piece (311).

6. The pole piece die cutting machine for the lithium ion battery production line according to claim 5, wherein the support ring (5) is further provided with magnets (521) corresponding to the support rods (52) one by one, and when the magnets (521) are adsorbed to the support rods (52), the support rods (52) lose support of the pole pieces (311), so that the pole pieces (311) are laid at the bottom end where the pole pieces (311) are placed.

7. The pole piece die cutting machine for the lithium ion battery production line according to claim 6, wherein a plurality of locking assemblies for locking the bearing assemblies are arranged on the outer side wall of the support ring (5), and fixing rods (42) corresponding to the locking assemblies one to one are fixedly arranged in the base (4).

8. The pole piece die-cutting machine for the lithium ion battery production line according to claim 7, wherein the locking assembly comprises a fixed block (51) which is slidably sleeved on the fixed rod (42), a locking block (511) is slidably arranged in the fixed block (51), a second elastic member (5111) is arranged between the locking block (511) and the fixed block (51), and the locking block (511) protrudes out of the fixed block (51) due to the elastic force of the second elastic member (5111).

9. The pole piece die-cutting machine for the lithium ion battery production line according to claim 8, wherein the base (4) is provided with a plurality of stabilizing posts (41) and a first elastic member (411) sleeved on the stabilizing posts (41), and when cutting is performed, the sliding block (6) is contracted into the base (4) to extrude the locking block (511), so that the fixing block (51) slides downwards along the fixing rod (42) under the elastic force of the elastic rope (512).

10. The pole piece die cutting machine for the lithium ion battery production line according to claim 7, wherein telescopic rods (421) corresponding to the fixing rods (42) one by one are arranged inside the fixing shell (2), and telescopic ends of the telescopic rods (421) are sleeved on the fixing rods (42).