CN211998127U

CN211998127U - Intelligent folding equipment for garbage bag

Info

Publication number: CN211998127U
Application number: CN202020429333.7U
Authority: CN
Inventors: 蔡豪阳; 常建明; 张柏文
Original assignee: Dongguan Shanze Intelligent Technology Co ltd
Current assignee: Dongguan Shanze Intelligent Technology Co ltd
Priority date: 2020-03-30
Filing date: 2020-03-30
Publication date: 2020-11-24
Anticipated expiration: 2030-03-30

Abstract

The utility model relates to an intelligent folding device for garbage bags, which comprises a feeding mechanism, a folding mechanism and a discharging mechanism; the folding mechanism comprises a workbench, a sleeve fixing column, a Z-direction sliding rail assembly, a Z-direction servo motor, a suction nozzle mounting platform, a suction nozzle moving cylinder, a semi-finished product cylinder wall structural part, a material cutting knife platform, a cutter lifting cylinder, a pressing claw, a blade mounting frame, a horizontal sliding rail assembly and blades. The utility model discloses a can carry out a series of operations such as material loading to the disposal bag automatically, it is folding, band and conveying unloading, it can not only carry out folding once or many times to the disposal bag automatically according to the needs of production, it still has folding efficient and folding effectual advantage, and it has broken and has not can carry out folding equipment problem to the disposal bag automatically at present, and greatly reduced the cost that the consumer bought the disposal bag, its purchase cost is 5-6 yuan now, compare at 50-60 yuan with the purchase cost of tradition, its purchase cost has reduced 10 times.

Description

Intelligent folding equipment for garbage bag

Technical Field

The utility model relates to a folding equipment of disposal bag intelligence.

Background

The traditional garbage bag is sold together with the storage box of the intelligent garbage can, so that the price of the traditional garbage bag is very high, the traditional garbage bag generally needs 50-60 yuan, and a user needs to take out the garbage bag from the storage box and put the garbage bag into the intelligent garbage can for use when using the garbage bag, so that great inconvenience is brought to the user. Therefore, in order to overcome the defects of the existing intelligent garbage bin, the applicant develops a folding device capable of automatically folding the garbage bag into a hollow cylindrical structure, which not only realizes automatic production, but also greatly reduces the purchase cost or purchase expense of a consumer, and the purchase expense can be reduced to 5-6 yuan.

Disclosure of Invention

The to-be-solved technical problem of the utility model is to provide a folding equipment of disposal bag intelligence, its holistic structural design has realized that can accomplish a series of operations such as material loading conveying, folding, band and conveying unloading automatically to the disposal bag, it can not only carry out folding once or many times to the disposal bag according to the needs of production automatically, it still has folding efficient and folding effectual advantage, and it has broken the problem that can not carry out folding equipment to the disposal bag automatically at present, and greatly reduced the cost that the consumer bought the disposal bag, its purchase cost is 5-6 yuan now, compare at 50-60 yuan with the purchase cost of passing entirely, its purchase cost has reduced 10 times. The utility model discloses a realize through following technical scheme:

an intelligent folding device for garbage bags comprises a feeding mechanism, wherein a folding mechanism capable of automatically folding garbage bags is arranged on one side of the feeding mechanism, a semi-finished product discharging mechanical arm is arranged on one side of the folding mechanism, and a finished product discharging mechanism is arranged on one side of the semi-finished product discharging mechanical arm; the feeding mechanism comprises a rack, a material feeding reel is arranged in the rack, a first tensioning device is arranged on the rack, a second tensioning device is arranged below one side of the first tensioning device, a third tensioning device is arranged above one side of the second tensioning device, a fourth tensioning device is arranged below one side of the third tensioning device, a fifth tensioning device is arranged above one side of the fourth tensioning device, a sixth tensioning device is arranged above one side of the fifth tensioning device, a seventh tensioning device is arranged below one side of the sixth tensioning device, an eighth tensioning device is arranged above one side of the seventh tensioning device, and a ninth tensioning device is arranged on one side of the eighth tensioning device. A cutting motor is arranged on one side of the feeding reel and is used for driving the feeding reel to rotate and cut.

Preferably, the folding mechanism comprises a workbench, the middle of the workbench is of a hollow structure, a sleeve is arranged above the middle of the workbench, sleeve fixing columns are respectively arranged on the four corners of the workbench, each sleeve fixing column and the sleeve are connected with a Z-direction slide rail assembly, a Z-direction servo motor is arranged at the upper end of each Z-direction slide rail assembly, a suction nozzle mounting platform is arranged on the periphery of the lower end of the sleeve, a plurality of suction nozzles are uniformly distributed on the suction nozzle mounting platform at equal intervals, and a suction nozzle moving cylinder is arranged on one side of each suction nozzle; a circular semi-finished product cylinder wall structural part is arranged below the suction nozzle mounting platform; the left side and the right side of the workbench are respectively provided with a material cutting knife platform, a cutter is arranged above each material cutting knife platform, a cutter lifting cylinder is arranged below each material cutting knife platform, and each cutter lifting cylinder penetrates through the material cutting knife platform and is connected with a cutter positioned above the material cutting knife platform; the front side of the lower part of each sleeve fixing column is provided with a pressing claw for pressing the folded garbage bag to prevent the garbage bag from loosening or shifting, and a pressing claw cylinder is connected with each pressing claw and can drive the pressing claw to move up and down to press an object placed below the pressing claw; the utility model discloses a garbage bag garbage can, including workstation, blade mounting bracket, a plurality of horizontal slide rail subassembly, lift cylinder, a plurality of horizontal slide rail subassembly, the top of workstation is provided with the blade mounting bracket, is provided with a plurality of horizontal slide rail subassembly above the blade mounting bracket, is provided with the lift cylinder below the blade mounting bracket, and a plurality of horizontal slide rail subassembly is arranged into circularly with equal interval, slides in the top of every horizontal slide rail subassembly to be provided with can strut the disposal bag voluntarily, in order to conveniently carry out folding blade to it, and the. Each blade is arranged into a vertical plate-shaped structure. Each blade can do inward contraction movement or outward expansion movement through the horizontal sliding rail, and the plurality of blades can do lifting movement along with the blade mounting frame under the driving of the lifting cylinder. The semi-finished product cylinder wall structural member is a cylindrical model which can be used for conveniently folding and forming the garbage bag.

Preferably, the finished product blanking mechanism comprises a blanking rack, finished product blanking manipulators are respectively arranged on the front side and the rear side of the top surface of the blanking rack, and a belt binding machine is arranged on one side of one of the finished product blanking manipulators. The specific structure and operation principle of the belt binding machine are well known and will not be explained in detail here.

Preferably, the semi-finished product blanking manipulator comprises a rotary servo motor, a clamping finger cylinder mounting plate is arranged on the rotary servo motor, a plurality of clamping finger cylinders are uniformly distributed on the circumferential edge of the clamping finger cylinder mounting plate at equal intervals, and the clamping finger cylinders are actuating devices which use compressed air as power and are used for clamping or grabbing workpieces, and the semi-finished product blanking manipulator is common knowledge and will not be explained in detail herein.

Preferably, each finished product unloading manipulator includes that X is to removing the module, and X is provided with Z to removing the module to one side of removing the module, and Z is provided with the cylinder mounting panel to the front side that removes the module, and clamping jaw cylinder is installed respectively at the left and right ends of cylinder mounting panel, is provided with the clamping jaw that can clip the folding into columniform disposal bag below every clamping jaw cylinder. The clamping jaw can move up and down to press from both sides and get the work piece under Z moves the module and X to moving the common drive of module, can remove about again and press from both sides and get the work piece.

Preferably, the first tensioning device, the second tensioning device, the third tensioning device, the fourth tensioning device, the fifth tensioning device, the sixth tensioning device, the seventh tensioning device, the eighth tensioning device and the ninth tensioning device each include two fixing frames symmetrically distributed in the front-back direction, and the two fixing frames symmetrically distributed in the front-back direction are connected with the rotating rod.

Preferably, the Z-direction sliding rail assembly and the Z-direction moving module both comprise a Z-direction sliding rail and a Z-direction sliding block sliding on the Z-direction sliding rail. Horizontal slide rail set spare and X are all including the slide rail to removing the module, and in the gliding slider of the higher authority of slide rail, and be connected with the slider and promote the slider and carry out gliding sliding cylinder on the slide rail.

Preferably, a PLC control system or a controller is connected with the feeding mechanism, the folding mechanism and the blanking mechanism respectively, the controller is a PLC programmable logic controller, and the PLC programmable logic controller can adopt but is not limited to a PLC with a brand of VIGOR/Fengwu and a goods number of 4586 sold on Alibara. The operator can set various parameters for controlling the operation of each component through the controller according to the production requirement.

The utility model relates to an intelligent folding device for garbage bags, which comprises a feeding mechanism, a folding mechanism and a discharging mechanism; the folding mechanism comprises a workbench, a sleeve fixing column, a Z-direction sliding rail assembly, a Z-direction servo motor, a suction nozzle mounting platform, a suction nozzle moving cylinder, a semi-finished product cylinder wall structural part, a material cutting knife platform, a cutter lifting cylinder, a pressing claw, a blade mounting frame, a horizontal sliding rail assembly and blades. The utility model firstly sleeves or winds the garbage bag material roll on the outer circumference of the feeding scroll, when the feeding scroll is driven by a cutting motor to rotate and cut, the initial end of the garbage bag is firstly pulled out, so that the initial end of the garbage bag is sequentially transmitted to the lower part of the sleeve through the first tensioning device, the second tensioning device, the third tensioning device, the fourth tensioning device, the fifth tensioning device, the sixth tensioning device, the seventh tensioning device, the eighth tensioning device and the ninth tensioning device and penetrates out from the lower part of the sleeve, then the plurality of blades synchronously ascend under the driving of the lifting cylinder, then the plurality of blades synchronously expand outwards under the driving of the horizontal slide rail, so that the outwards expanded area of the garbage bag is larger than the area of the sleeve, then the sleeve presses downwards along with a plurality of Z-direction slide rail assemblies and under the common driving of Z-direction servo motors connected with the Z-direction slide rail assemblies, the garbage bag folding device can automatically fold garbage bags conveyed below the sleeve, after the garbage bags are folded once, the sleeve moves upwards along with a plurality of Z-direction slide rail assemblies under the common drive of Z-direction servo motors connected with the Z-direction slide rail assemblies to reset, simultaneously, each pressing claw moves downwards synchronously to press the edge of the folded garbage bags on a semi-finished product cylinder wall structural member, then, a plurality of blades synchronously move downwards and furl to return to the initial position, the operation is repeated until the garbage bags reach the folding times required by production, then, the cutter can cut off the garbage bags which are folded for a certain time along with the cutting cutter platform and driven by the cutter lifting cylinder to rise upwards along with the cutting cutter platform, and after the garbage bags are cut off by the cutter, the cutter moves downwards along with the cutting cutter platform and driven by the cutter lifting cylinder, then, the plurality of suction nozzles are driven by the suction nozzle moving cylinder connected with the suction nozzles to synchronously suck the garbage bags, the garbage bags can be pulled open and pulled to be square, the phenomenon that the garbage bags are wrinkled after being cut by a cutter is avoided, the plurality of blades can conveniently and simultaneously perform ascending motion under the driving of the lifting cylinder at the next time, each blade can conveniently perform outward expanding motion synchronously under the driving of the horizontal sliding rail component connected with the blade, then, the semi-finished product blanking mechanical arm transfers the garbage bags to one side of the strapping machine from the folding mechanism, the strapping machine can automatically strap the garbage bags which are folded for a certain number of times (the specific structure and the strapping principle of the strapping machine are known and will not be explained in detail here), after the strapping machine completes the strapping operation on the garbage bags, the finished product blanking mechanical arm automatically clamps the garbage bags which are strapped and conveys the garbage bags, the integral structural design of the folding garbage bag folding machine realizes a series of operations of uncoiling, feeding, conveying, folding, bundling, conveying, blanking and the like of the garbage bag, not only can the garbage bag be folded for one time or multiple times according to production requirements, but also has the advantages of high folding efficiency and good folding effect, breaks through the problem that no equipment capable of automatically folding the garbage bag exists at present, greatly reduces the cost of purchasing the garbage bag by consumers, and reduces the purchase cost by 5-6 yuan compared with the conventional purchase cost of 50-60 yuan, and the purchase cost is reduced by 10 times.

Drawings

For the purpose of illustration, the invention is described in detail with reference to the following preferred embodiments and the accompanying drawings.

Fig. 1 is the utility model discloses a perspective view of disposal bag intelligence folding apparatus.

Fig. 2 is a perspective view of another direction of the intelligent folding device for garbage bags of the utility model.

Fig. 3 is a perspective view of the folding mechanism, the sixth tensioning device, the seventh tensioning device, the eighth tensioning device, the ninth tensioning device and the combined structure of the intelligent folding device for garbage bags of the present invention.

Fig. 4 is an enlarged perspective view of a part a of fig. 3 of the utility model of an intelligent folding device for garbage bags.

Fig. 5 is an enlarged perspective view of the blades of the intelligent folding device for garbage bags of the present invention.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. The preferred embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In this embodiment, referring to fig. 1 to 5, the intelligent folding device for garbage bags of the present invention includes a feeding mechanism 1, a folding mechanism 2 is disposed on one side of the feeding mechanism 1, a semi-finished product blanking manipulator 3 is disposed on one side of the folding mechanism 2, and a finished product blanking mechanism 4 is disposed on one side of the semi-finished product blanking manipulator 3; the feeding mechanism 1 comprises a frame 10, a feeding reel is arranged in the frame 10, a first tensioning device 11 is arranged on the frame 10, a second tensioning device is arranged below one side of the first tensioning device 11, a third tensioning device 12 is arranged above one side of the second tensioning device, a fourth tensioning device is arranged below one side of the third tensioning device 12, a fifth tensioning device 13 is arranged above one side of the fourth tensioning device, a sixth tensioning device 14 is arranged above one side of the fifth tensioning device 13, a seventh tensioning device 15 is arranged below one side of the sixth tensioning device 14, an eighth tensioning device 16 is arranged above one side of the seventh tensioning device 15, and a ninth tensioning device 17 is arranged on one side of the eighth tensioning device 16.

In one embodiment, the folding mechanism 2 includes a workbench 20, the middle of the workbench 20 is a hollow structure, a sleeve 21 is arranged above the middle of the workbench 20, sleeve fixing columns 22 are respectively arranged on the four corners of the workbench 20, each sleeve fixing column 22 and the sleeve 21 are connected with a Z-direction sliding rail assembly 23, a Z-direction servo motor 24 is arranged at the upper end of each Z-direction sliding rail assembly 23, a suction nozzle mounting platform 25 is arranged on the periphery of the lower end of the sleeve 21, a plurality of suction nozzles 26 are uniformly distributed on the suction nozzle mounting platform 25 at equal intervals, and a suction nozzle moving cylinder is arranged on one side of each suction nozzle 26; a circular semi-finished product cylinder wall structural member 27 is arranged below the suction nozzle mounting platform 25; the left side and the right side of the workbench 20 are respectively provided with a material cutting knife platform 28, a cutting knife 29 is arranged on each material cutting knife platform 28, a cutting knife lifting cylinder is arranged below each material cutting knife platform 28, and each cutting knife lifting cylinder penetrates through the material cutting knife platforms 28 and is connected with the cutting knife 29; the front side of the lower part of each sleeve fixing column 22 is provided with a pressing claw 291; a blade mounting frame 292 is disposed below the working platform 20, a plurality of horizontal sliding rail assemblies 293 are disposed on the blade mounting frame 292, the horizontal sliding rail assemblies 293 are arranged at equal intervals to form a circle, a blade 294 is slidably disposed on each horizontal sliding rail assembly 293, and the blade 294 is perpendicular to the horizontal sliding rail assemblies 293.

In one embodiment, the finished product blanking mechanism 4 includes a blanking frame 41, finished product blanking manipulators 42 are respectively disposed on the front and rear sides of the top surface of the blanking frame 41, and a banding machine 43 is disposed on one side of one of the finished product blanking manipulators 42.

In one embodiment, the finished product blanking manipulator 42 includes an X-direction moving module 421, a Z-direction moving module 422 is disposed on one side of the X-direction moving module 421, a cylinder mounting plate 423 is disposed on the front side of the Z-direction moving module 422, clamping jaw cylinders 424 are respectively mounted at the left and right ends of the cylinder mounting plate 423, and a clamping jaw 425 capable of clamping a garbage bag folded into a cylindrical shape is disposed below each clamping jaw cylinder 424.

In one embodiment, the first tensioning device 11, the second tensioning device, the third tensioning device 12, the fourth tensioning device, the fifth tensioning device 13, the sixth tensioning device 14, the seventh tensioning device 15, the eighth tensioning device 16 and the ninth tensioning device 17 each include two fixing frames 18 symmetrically distributed in the front-back direction, and the two fixing frames 18 symmetrically distributed in the front-back direction are connected with a rotating rod 19.

In one embodiment, the operation flow of the intelligent garbage bag folding device is as follows: firstly, a garbage bag material roll is sleeved or wound on the outer circumference of a feeding scroll, when the feeding scroll is driven by a cutting motor to rotate and cut, the initial end of the uncoiled garbage bag is pulled out, and is sequentially transmitted to the lower surface of a sleeve 21 through a first tensioning device 11, a second tensioning device, a third tensioning device 12, a fourth tensioning device, a fifth tensioning device 13, a sixth tensioning device 14, a seventh tensioning device 15, an eighth tensioning device 16 and a ninth tensioning device 17, and then penetrates out of the lower surface of the sleeve 21, then a plurality of blades 294 are synchronously lifted under the driving of a lifting cylinder, then the blades 294 synchronously and outwards expand under the driving of a horizontal slide rail (so as to realize the function of opening the garbage bag), so that the outwards expanded area of the garbage bag is larger than that of the sleeve 21, and then the sleeve 21 follows a plurality of Z-direction slide rail assemblies 23 and is jointly arranged on a Z-direction servo motor 24 respectively connected with the Z-direction slide rail assemblies 23 The driving downward pressing movement makes it realize that the garbage bag conveyed to the lower part of the sleeve 21 can be automatically folded, after the garbage bag is folded once, the sleeve 21 moves upward and returns to the original position under the common driving of the Z-direction servo motor 24 respectively connected with each Z-direction slide rail assembly 23 along with the plurality of Z-direction slide rail assemblies 23, simultaneously, each pressing claw 291 moves downward synchronously to press the edge of the folded garbage bag on the semi-finished product cylinder wall structural member 27, then, the plurality of blades 294 move in a descending movement synchronously to fold to return to the original position, the operations are repeated until the garbage bag reaches the folding times required to be set for production, then, the cutter 29 cuts off the garbage bag which is folded for a certain number of times along with the cutting knife platform 28 under the driving of the cutter lifting cylinder, after the garbage bag is cut off by the cutter 29, the cutter 29 moves downwards along with the stock-cutting cutter platform 28 and is driven by the cutter lifting cylinder to reset, then, the plurality of suction nozzles 26 are driven by the suction nozzle moving cylinder connected with the suction nozzles to synchronously suck the periphery of the garbage bag, so that the garbage bag can be pulled to be square, the phenomenon that the garbage bag is folded after being cut by the cutter 29 is prevented, thereby facilitating the next synchronous ascending movement of the plurality of blades 294 and the next synchronous outward expansion movement of the plurality of blades 294, then, the semi-finished product blanking manipulator 3 transfers the garbage bags from the folding mechanism 2 to one side of the strapping machine 43, the strapping machine 43 can automatically strap the garbage bags which are folded for a certain number of times, after the strapping machine 43 completes strapping operations on the garbage bags, the finished product blanking manipulator 42 automatically clamps and clamps the garbage bags with the straps completed, and conveys the garbage bags to one side of the equipment for blanking, and the process is repeated.

The utility model relates to an intelligent folding device for garbage bags, which comprises a feeding mechanism, a folding mechanism and a discharging mechanism; the folding mechanism comprises a workbench, a sleeve fixing column, a Z-direction sliding rail assembly, a Z-direction servo motor, a suction nozzle mounting platform, a suction nozzle moving cylinder, a semi-finished product cylinder wall structural part, a material cutting knife platform, a cutter lifting cylinder, a pressing claw, a blade mounting frame, a horizontal sliding rail assembly and blades. The utility model discloses holistic structural design has realized opening a book the material loading conveying to the disposal bag automatically, it is folding, a series of operations such as band and conveying unloading, it can not only carry out folding once or many times to the disposal bag according to the needs of production automatically, it still has folding efficient and folding effectual advantage, and it has broken the problem that can not carry out folding equipment to the disposal bag automatically at present, and greatly reduced the cost that the consumer purchased the disposal bag, the purchase cost of present its is 5-6 yuan, compare at 50-60 yuan with the purchase cost of passing in unison, its purchase cost has reduced 10 times.

The above-mentioned embodiment is only an example of the present invention, and is not intended to limit the scope of the present invention, and all technical solutions that are the same as or equivalent to the content of the claims of the present invention should be included in the scope of the present invention.

Claims

1. The utility model provides a disposal bag intelligence folding apparatus which characterized in that: the automatic feeding device comprises a feeding mechanism, wherein a folding mechanism is arranged on one side of the feeding mechanism, a semi-finished product discharging manipulator is arranged on one side of the folding mechanism, and a finished product discharging mechanism is arranged on one side of the semi-finished product discharging manipulator; the feeding mechanism comprises a rack, a material feeding reel is arranged in the rack, a first tensioning device is arranged on the rack, a second tensioning device is arranged below one side of the first tensioning device, a third tensioning device is arranged above one side of the second tensioning device, a fourth tensioning device is arranged below one side of the third tensioning device, a fifth tensioning device is arranged above one side of the fourth tensioning device, a sixth tensioning device is arranged above one side of the fifth tensioning device, a seventh tensioning device is arranged below one side of the sixth tensioning device, an eighth tensioning device is arranged above one side of the seventh tensioning device, and a ninth tensioning device is arranged on one side of the eighth tensioning device.

2. The intelligent folding device for garbage bags according to claim 1, characterized in that: the folding mechanism comprises a workbench, the middle of the workbench is of a hollow structure, a sleeve is arranged above the middle of the workbench, sleeve fixing columns are respectively arranged on the four corners of the workbench, each sleeve fixing column and the sleeve are connected with a Z-direction sliding rail assembly, a Z-direction servo motor is arranged at the upper end of each Z-direction sliding rail assembly, a suction nozzle mounting platform is mounted on the periphery of the lower end of the sleeve, a plurality of suction nozzles are uniformly distributed on the suction nozzle mounting platform at equal intervals, and a suction nozzle moving cylinder is arranged on one side of each suction nozzle; a circular semi-finished product cylinder wall structural part is arranged below the suction nozzle mounting platform; the left side and the right side of the workbench are respectively provided with a material cutting knife platform, a cutting knife is arranged above each material cutting knife platform, a cutting knife lifting cylinder is arranged below each material cutting knife platform, and each cutting knife lifting cylinder penetrates through the material cutting knife platforms and is connected with the cutting knife; the front side of the lower part of each sleeve fixing column is provided with a pressing claw; the lower part of workstation is provided with the blade mounting bracket, is provided with a plurality of horizontal sliding rail set spare above the blade mounting bracket, and a plurality of horizontal sliding rail set spare is arranged into circularly with equal interval, slides on every horizontal sliding rail set spare and is provided with the blade, and the blade is perpendicular setting with horizontal sliding rail set spare.

3. The intelligent folding device for garbage bags according to claim 1, characterized in that: the finished product unloading mechanism comprises an unloading rack, finished product unloading manipulators are arranged on the front side and the rear side of the top surface of the unloading rack respectively, and a belt binding machine is arranged on one side of one of the finished product unloading manipulators.

4. The intelligent folding device of disposal bag of claim 3, wherein: finished product unloading manipulator includes that X is provided with Z to removing the module to one side that removes the module, and Z is provided with the cylinder mounting panel to the front side that removes the module, and clamping jaw cylinder is installed respectively at both ends about the cylinder mounting panel, is provided with below every clamping jaw cylinder to carry the clamping jaw that folds into columniform disposal bag.

5. The intelligent folding device for garbage bags according to claim 1, characterized in that: the first tensioning device, the second tensioning device, the third tensioning device, the fourth tensioning device, the fifth tensioning device, the sixth tensioning device, the seventh tensioning device, the eighth tensioning device and the ninth tensioning device respectively comprise two fixing frames which are symmetrically distributed front and back, and the two fixing frames which are symmetrically distributed front and back are connected with a rotating rod.