SUMMERY OF THE UTILITY MODEL
In order to solve the problems, the utility model provides a laser cutting device capable of automatic blanking, which comprises an uncoiling component, a steel coil leveler, a laser cutting machine and a blanking mechanism, wherein the uncoiling component is used for opening coiled coil materials and leveling the coiled coil materials by the steel coil leveler, the leveled coil materials are cut by the laser cutting machine, and finished products after cutting are blanked and stacked by the blanking mechanism; the laser cutting device capable of automatically discharging provided by the utility model has high automation degree, simple structure and easy realization; the specific contents are as follows:
a laser cutting device capable of automatically discharging comprises an uncoiling assembly, a steel coil leveling machine, a laser cutting machine and a discharging mechanism; the uncoiling assembly, the steel coil leveler, the laser cutting machine and the blanking mechanism are arranged in sequence; the uncoiling assembly comprises an uncoiler, a hydraulic trolley and a hydraulic trolley track; the length direction of the hydraulic trolley track is perpendicular to the length direction of the lathe bed of the laser cutting machine; the hydraulic trolley moves on the hydraulic trolley track; the hydraulic trolley is used for conveying the steel coil to the uncoiler; the blanking mechanism comprises a blanking support upright post, a blanking cross beam, a blanking sliding plate, a blanking lifting shaft and a blanking sliding plate driving mechanism; the blanking lifting shaft is perpendicular to the blanking cross beam; the blanking cross beam is fixedly connected with the blanking support upright post; the blanking sliding plate is connected with the blanking lifting shaft in a sliding mode.
Preferably, the laser cutting machine comprises a machine body, a beam of the laser cutting machine and a laser cutting head assembly; the beam of the laser cutting machine is arranged on the lathe bed, and the beam of the laser cutting machine is vertical to the length direction of the lathe bed; the laser cutting head assembly is arranged on a beam of the laser cutting machine.
Preferably, the laser cutting machine beam can move along the length direction of the bed.
Preferably, the laser cutting head assembly is movable on the beam.
Preferably, the blanking slide plate driving mechanism comprises a blanking speed reducer, a first blanking synchronizing wheel, a second blanking synchronizing wheel and a conveyor belt; the first blanking synchronizing wheel and the second blanking synchronizing wheel are respectively arranged at two ends of the blanking cross beam along the length direction; the conveying belt is sleeved on the first blanking synchronizing wheel and the second blanking synchronizing wheel; the blanking speed reducer is used for driving the first blanking synchronizing wheel to rotate; the blanking sliding plate is fixedly connected with the conveying belt.
Preferably, a blanking lifting motor is fixedly arranged on the sliding plate, and a gear is arranged at the shaft end of an output shaft of the blanking lifting motor; and a rack is arranged on the blanking lifting shaft along the length direction of the blanking lifting shaft, and the gear is meshed with the rack.
Preferably, the blanking mechanism further comprises a drag chain, one end of the drag chain is connected with the blanking cross beam in a sliding mode, and the other end of the drag chain is fixedly connected with the blanking lifting shaft.
The utility model has the advantages that:
the laser cutting device capable of automatically discharging provided by the invention comprises an uncoiling assembly, a steel coil leveler, a laser cutting machine and a discharging mechanism; the coil straightening machine comprises an uncoiling assembly, a coil straightening machine, a laser cutting machine and a blanking mechanism, wherein the uncoiling assembly is used for opening coiled coil materials, then the coiled coil materials are leveled by the coil straightening machine, and the leveled coil materials are cut by the laser cutting machine; the blanking sliding plate driving mechanism drives the blanking sliding plate to move on the blanking cross beam, and the blanking sliding plate is in sliding connection with the blanking lifting shaft, so that the blanking mechanism can perform blanking and stacking on cut finished products.
Drawings
FIG. 1 is a structural diagram of a laser cutting device capable of automatic blanking according to the present invention;
FIG. 2 is a structural diagram of the blanking mechanism in FIG. 1;
FIG. 3 is a block diagram of the gripper mechanism of FIG. 1;
FIG. 4 is another block diagram of the gripper mechanism of FIG. 1;
FIG. 5 is a block diagram of the chuck assembly of FIG. 1;
fig. 6 is a structural view of the blanking lifting shaft in fig. 1.
The technical features indicated by the reference numerals in the drawings are as follows:
1. an uncoiling assembly; 1.1, an uncoiler; 1.2, hydraulic trolley; 1.3, a hydraulic trolley track; 2. a steel coil leveler; 3. a laser cutting machine; 3.1, a lathe bed; 3.2, laser cutting machine crossbeam; 3.3, laser cutting head assembly; 4. a blanking mechanism; 4.1, blanking and supporting the upright column; 4.1.1, blanking and supporting the vertical part of the upright post; 4.1.2, blanking and supporting the horizontal part of the upright post; 4.2, blanking cross beams; 4.3, a blanking sliding plate; 4.4, blanking lifting shafts; 4.5, a driving mechanism of the blanking sliding plate; 4.5.1, a blanking speed reducer; 4.5.2, a first blanking synchronizing wheel; 4.5.3, a second blanking synchronizing wheel; 4.5.4, conveyor belts; 4.6, a blanking lifting motor; 4.7, a first slide rail; 4.8, drag chain; 4.9, a third slide rail; 5. a steel coil; 6. a gripper mechanism; 6.1, transverse round tubes; 6.2, longitudinal round tubes; 6.3, a sucker component; 6.3.1, a gas pipe joint; 6.3.2, a spring telescopic rod; 6.3.3, a sucker; 6.3.4, a connecting rod; 6.3.5, a spring telescopic rod mounting seat; 6.4, hoop; 6.4.1, a hoop through groove; 6.4.2, first part; 6.4.3, second part; 6.4.4, third part; 6.5, an adjusting seat; 6.6, a connecting seat of a blanking mechanism; 6.6.1, connecting the horizontal part of the blanking mechanism; 6.6.2, connecting the vertical part of the blanking mechanism; 6.6.3 and reinforcing ribs.
Detailed Description
The following description of the embodiments of the present invention will be made with reference to the accompanying drawings:
the laser cutting device capable of automatically discharging shown in fig. 1 comprises an uncoiling assembly 1, a steel coil leveler 2, a laser cutting machine 3 and a discharging mechanism 4; the uncoiling component 1, the steel coil leveler 2, the laser cutting machine 3 and the blanking mechanism 4 are sequentially arranged. The uncoiling assembly 1 comprises an uncoiler 1.1, a hydraulic trolley 1.2 and a hydraulic trolley track 1.3; the uncoiler 1.1 is used for uncoiling the steel coil 5, so that the round steel coil 5 can be uncoiled; the hydraulic trolley 1.2 is used for installing a steel coil 5 on the uncoiler 1.1, and the hydraulic trolley 1.2 moves on the hydraulic trolley track 1.3. The length direction of the hydraulic trolley track 1.3 is perpendicular to the length direction of the lathe bed of the laser cutting machine 3, and the uncoiler 1.1 is arranged at one end of the hydraulic trolley track 1.3 along the length direction. The steel coil leveler 2 is used for leveling the uncoiled steel coil 5, so that the steel coil 5 becomes a flat steel plate. Coil of strip levelling machine 2 sets up open a book subassembly 1 with between the laser cutting machine 3, coil of strip levelling machine 2 sets up laser cutting machine 3's the length direction's in the lathe bed one end, laser cutting machine 3's the length direction's in the lathe bed the other end is provided with unloading mechanism 4.
The structure of the laser cutting machine 3 is shown in fig. 1 and comprises a machine body 3.1, a laser cutting machine beam 3.2 and a laser cutting head assembly 3.3, wherein the laser cutting machine beam 3.2 can move along the length direction of the machine body 3.1, and the laser cutting head assembly 3.3 can move on the beam 3.2 along the width direction of the machine body 3.1. The working mode of the laser cutting machine 3 is the same as that of a conventional laser cutting machine, and is not described herein.
The working process of the laser cutting device capable of automatically discharging is as follows:
1, manually placing a steel coil 5 on a hydraulic trolley 1.2 by using a traveling crane, wherein the hydraulic trolley 1.2 moves along a hydraulic trolley track 1.3, the steel coil 5 is loaded into a main shaft of an uncoiler 1.1, and the central position of the steel coil 5 is adjusted and fixed;
2, starting the uncoiler 1.1, guiding a steel coil 5 into the steel coil leveler 2, adjusting the steel coil leveler 2 to ensure that the steel coil 5 is positioned at the center of a machine tool of the laser cutting machine 3, adjusting parameters of the steel coil leveler 2 according to the width and the thickness of the steel coil 5, and setting a proper feeding speed;
3, guiding the steel coil 5 leveled by the steel coil leveling machine 2 into a lathe bed 3.1 of the laser cutting machine 3;
4, guiding the graph of the cut finished product into the nesting software of the laser cutting machine 3, performing typesetting layout according to the gear of the steel coil 5, improving the utilization rate of materials, and selecting proper cutting process parameters according to the material and the thickness of steel;
and 5, blanking the cut finished products after cutting by the blanking mechanism 4, and blanking the cut finished products to a stacking platform by the blanking mechanism 4 until blanking is finished.
The structure of the blanking mechanism 4 is shown in fig. 2, and the blanking mechanism 4 comprises a blanking support upright post 4.1, a blanking cross beam 4.2, a blanking sliding plate 4.3, a blanking lifting shaft 4.4 and a blanking sliding plate driving mechanism 4.5; the structure of the blanking lifting shaft 4.4 is shown in fig. 6. The blanking support upright post 4.1 is fixedly connected with the ground, and plays a role in supporting the whole blanking mechanism 4. The number of the blanking support columns 4.1 is multiple, and three blanking support columns 4.1 are shown in fig. 2; the blanking support upright post 4.1 comprises a blanking support upright post vertical part 4.1.1 and a blanking support upright post horizontal part 4.1.2; the blanking support stand column horizontal part 4.1.2 is perpendicular to the blanking support stand column vertical part 4.1.1, the blanking support stand column vertical part 4.1.1 is used for being fixedly connected with the ground, the blanking support stand column horizontal part 4.1.2 is used for installing the blanking cross beam 4.2, and the weight of the blanking cross beam 4.2 is completely supported on the blanking support stand column horizontal part 4.1.2.
A blanking sliding plate driving mechanism 4.5 is arranged on the blanking cross beam 4.2; the blanking slide plate driving mechanism comprises a blanking speed reducer 4.5.1, a first blanking synchronizing wheel 4.5.2, a second blanking synchronizing wheel 4.5.3 and a conveyor belt 4.5.4; the first blanking synchronizing wheel 4.5.2 and the second blanking synchronizing wheel 4.5.3 are respectively arranged at two ends of the blanking cross beam 4.2 along the length direction, the conveyor belt 4.5.4 is sleeved on the first blanking synchronizing wheel 4.5.2 and the second blanking synchronizing wheel 4.5.3, the speed reducer 4.5.1 is arranged on the blanking cross beam 4.2, and the speed reducer 4.5.1 is used for driving the first blanking synchronizing wheel 4.5.2 to rotate. The blanking sliding plate 4.3 is fixedly connected with the conveying belt 4.5.4. When the blanking speed reducer 4.5.1 is started, the first blanking synchronizing wheel 4.5.2 is driven to rotate, so that the conveyor belt 4.5.4 is driven to move, and the blanking sliding plate 4.3 moves along the length direction of the blanking cross beam 4.2.
The blanking sliding plate 4.3 is in sliding connection with the blanking lifting shaft 4.4. The blanking sliding plate 4.3 is fixedly provided with a blanking lifting motor 4.6, the blanking sliding plate 4.3 is a rectangular plate, the blanking lifting motor 4.7 is arranged on one side of the blanking sliding plate 4.3, the blanking lifting shaft 4.4 is arranged on the other side of the blanking sliding plate 4.3, an output shaft of the blanking lifting motor 4.6 penetrates through the blanking sliding plate 4.3, a gear is arranged at the shaft end of the blanking lifting motor 4.6, a rack is arranged on the blanking lifting shaft 4.4 along the length direction of the blanking lifting shaft 4.4, and the rack is meshed with the gear, so that when the blanking lifting motor 4.6 is started, the rack is meshed with the gear, and the blanking lifting shaft 4.4 can be driven to move in the vertical direction.
The blanking cross beam 4.2 is provided with a first slide rail 4.7, the first slide rail 4.7 is arranged along the length direction of the blanking cross beam 4.2, the number of the first slide rails 4.7 is two, and the first slide rails 4.7 are arranged in parallel. One side of the blanking sliding plate 4.3 is provided with two first sliding blocks, the first sliding blocks correspond to the first sliding rails one by one, and the first sliding blocks slide on the first sliding rails 4.7, so that the effect of guiding the movement of the blanking sliding plate 4.3 is provided, and the effect of supporting the blanking sliding plate 4.3 is also achieved.
The blanking mechanism further comprises a drag chain 4.8, one end of the drag chain 4.8 is connected with the blanking cross beam 4.2 in a sliding mode, and the other end of the drag chain 4.8 is fixedly connected with the blanking lifting shaft 4.4. The drag chain 4.8 can play a role in supporting the weight of the blanking lifting shaft 4.4. The sliding connection mode of the drag chain 4.8 and the blanking cross beam 4.2 is as follows: one side of the blanking sliding plate 4.3 is fixedly provided with a drag chain installation seat 4.8.1, one end of the drag chain 4.8 is fixedly connected with the drag chain installation seat 4.8.1, and because the blanking sliding plate 4.3 is driven by the blanking sliding plate driving mechanism 4.5 to move on the blanking cross beam 4.2, one end of the drag chain 4.8 is connected with the blanking cross beam 4.2 in a sliding manner. As another embodiment, the sliding connection mode of the drag chain 4.8 and the blanking cross beam 4.2 is as follows: the blanking cross beam 4.2 is provided with a second slide rail, the second slide rail is arranged along the length direction of the blanking cross beam 4.2, a second slide block is arranged on the second slide rail in a sliding manner, and one end of the drag chain 4.8 is fixedly connected with the second slide block.
A third slide rail 4.9 is arranged on the blanking lifting shaft 4.4, a third slide block is arranged on the blanking sliding plate 4.4, and the third slide block slides on the third slide rail 4.9 and plays a role in guiding the movement of the blanking lifting shaft 4.4. The number of most third slide rails 4.9 is two, two third slide rails 4.9 set up follow on the unloading lift shaft 4.4 the left and right sides of unloading crossbeam 4.2 direction, the number of third slider is two the third slider sets up follow on the unloading slide 4.4 the left and right sides of the length direction of unloading crossbeam 4.2, third slide rails 4.9 with the third slider one-to-one.
The utility model provides an unloading mechanism 4's working process as follows:
the blanking speed reducer 4.5.1 is started to drive the first blanking synchronizing wheel 4.5.2 to rotate, so as to drive the transmission belt 4.5.4 to move along the horizontal direction, so that the blanking lifting shaft 4.4 moves along the horizontal direction, and the blanking lifting shaft 4.4 moves downwards through the meshing of a gear at the shaft end of an output shaft of the blanking lifting motor 4.6 and a rack on the blanking lifting shaft 4.4; then, grabbing and cutting a finished product through a sucker assembly; then the blanking lifting shaft 4.4 moves upwards, meanwhile, the blanking lifting shaft 4.4 moves along the horizontal direction, and a cut finished product door grabbed by the sucker component is placed on a stacking platform; and the processes are sequentially circulated to finish automatic blanking.
The blanking mechanism 4 provided by the utility model can realize automatic blanking of cut samples, has high efficiency and can realize automatic production of plates; compared with the prior art that the robot is used for blanking, the blanking mechanism in the application is low in cost, simple in structure and easy to realize.
The structure of the gripper mechanism 6 is shown in fig. 3, and the gripper mechanism 6 comprises a transverse round tube 6.1, a plurality of longitudinal round tubes 6.2 and a plurality of sucker components 6.3; the plurality of longitudinal round pipes 6.2 are arranged in parallel and are perpendicular to the transverse round pipes 6.1, and each longitudinal round pipe 6.2 is connected with the transverse round pipe 6.1 through a hoop 6.4; the longitudinal circular tube 6.2 is provided with a plurality of adjusting seats 6.5, the adjusting seats 6.5 correspond to the sucker components 6.3 one by one, and the adjusting seats 6.5 are fixedly connected with the sucker components 6.3.
As one embodiment, the anchor ear 6.4 is a cuboid, a transverse through hole and a longitudinal through hole are arranged on the anchor ear 6.4, the longitudinal through hole is arranged below the transverse through hole, the transverse circular tube 6.1 passes through the transverse through hole, and the longitudinal circular tube 6.2 passes through the longitudinal through hole. Staple bolt 6.4's top is provided with staple bolt through groove 6.4.1, the staple bolt through groove 6.4.1 the direction with horizontal pipe 6.1 is parallel, staple bolt through groove 6.4.1 with horizontal through-hole intercommunication, staple bolt through groove 6.4.1 will staple bolt left side and staple bolt right side are cut apart into on staple bolt 6.4's the upper portion staple bolt left side with all be provided with the screw thread through-hole on the staple bolt right side, the direction of screw thread through-hole with vertical pipe 6.2 is parallel. Will horizontal pipe 6.1 passes horizontal through-hole will vertical pipe 6.2 passes vertical through-hole, retaining member pass respectively locking behind the screw thread through-hole on staple bolt left side and the staple bolt right side, thereby will vertical pipe 6.2 is fixed on horizontal pipe 6.1.
As another embodiment, as shown in fig. 4, the anchor ear 6.4 includes a first portion 6.4.2, a second portion 6.4.3 and a third portion 6.4.4; the first part 6.4.2, the second part 6.4.3 and the third part 6.4.4 are arranged from top to bottom in sequence, a groove is arranged on the lower surface of the first part 6.4.2, a groove is arranged on the upper surface of the second part 6.4.3, and the groove on the lower surface of the first part 6.4.2 and the groove on the upper surface of the second part 6.4.3 are matched to form a containing space for containing the transverse round pipe 6.1; grooves are formed in the lower surface of the second portion 6.4.3 and the upper surface of the third portion 6.4.4, a containing space for containing the longitudinal round pipe 6.2 is formed by the lower surface of the second portion 6.4.3 and the grooves in the upper surface of the third portion 6.4.4, the number of the third portions 6.4.4 in each hoop 6.4 is two, and the two third portions 6.4.4 are symmetrically arranged by taking the central shaft of the transverse round pipe 6.1 as an axis. Threaded through holes are formed in the first part 6.4.2, the second part 6.4.3 and the third part 6.4.4, and locking members are locked after passing through the threaded through holes in the first part 6.4.2, the second part 6.4.3 and the third part 6.4.4, so that the first part 6.4.2, the second part 6.4.3 and the third part 6.4.4 are locked.
When the position of the longitudinal round pipe 6.2 on the transverse round pipe 6.1 needs to be adjusted, only the locking piece on the hoop 6.4 needs to be loosened, and the locking piece is locked after the position of the longitudinal round pipe 6.2 is adjusted.
Adjust and be provided with on the seat 6.5 and adjust a through-hole, vertical pipe 6.2 passes adjust a through-hole the top of adjusting seat 6.5 is provided with adjusts a logical groove, adjust the direction that a logical groove with vertical pipe 6.2 is parallel, adjust a logical groove with adjust a through-hole intercommunication, it will to adjust a logical groove adjust a left side and adjust a right side cut apart into on the upper portion of adjusting seat 6.5 adjust a left side with all be provided with the screw thread through-hole on adjusting a right side, the retaining member passes adjust a left side with adjust locking behind the screw thread through-hole on the seat right side, thereby will adjust seat 6.5 and fix on vertical pipe 6.2. When the position of the adjusting seat 6.5 on the longitudinal circular tube 6.2 needs to be adjusted, only the locking piece needs to be loosened, and then the locking piece is locked after the position of the adjusting seat 6.5 is adjusted. Through adjusting adjust seat 6.5, can adjust vertical pipe 6.2 is in position on the horizontal pipe 6.1 changes sucking disc subassembly 6.3's the mode of arranging to can adapt to snatching of the panel of different area sizes.
As shown in fig. 5, the suction cup assembly 6.3 comprises a gas pipe joint 6.3.1, a spring telescopic rod 6.3.2 and a suction cup 6.3.3; spring telescopic link 6.3.2 is hollow structure, spring telescopic link 6.3.2 is vertical direction setting, air pipe connector 6.3.1 with spring telescopic link 6.3.2's upper end intercommunication, sucking disc 6.3.3 with spring telescopic link 6.3.2's lower extreme intercommunication, air pipe connector 6.3.1 is used for admitting air and giving vent to anger.
The sucker assembly 6.3 further comprises a connecting rod 6.3.4 and a spring telescopic rod mounting seat 6.3.5; one end of the connecting rod 6.3.4 with adjust seat 6.5 fixed connection, the other end of connecting rod 6.3.4 with spring telescopic link mount pad 6.3.5 fixed connection. Spring telescopic link mount pad 6.3.5 the structure with adjust 6.5 the structure similar be provided with spring telescopic link mount pad through-hole on the spring telescopic link mount pad 6.3.5 the top of spring telescopic link mount pad 6.3.5 is provided with the logical groove of spring telescopic link mount pad, the logical groove of spring telescopic link mount pad with spring telescopic link mount pad through-hole intercommunication, the logical groove of spring telescopic link mount pad will spring telescopic link mount pad 6.3.5's upper portion is cut apart into spring telescopic link mount pad left side and spring telescopic link mount pad right side all be provided with the screw thread through-hole on spring telescopic link mount pad left side and the spring telescopic link mount pad right side. And the locking piece respectively penetrates through the threaded through holes on the left side of the spring telescopic rod mounting seat and the right side of the spring telescopic rod mounting seat and then is locked.
The spring telescopic rod 6.3.2 comprises a telescopic rod body, a spring and a connecting piece; the telescopic link body divide into first section telescopic link and second section telescopic link, first section telescopic link and second section telescopic link integrated into one piece, first section telescopic link sets up the top of second section telescopic link be provided with the helicitic texture on the first section telescopic link, the connecting piece cover is established on the helicitic texture, the connecting piece with spring telescopic link mount pad fixed connection. The spring telescopic rod further comprises a first nut and a second nut, the first nut and the second nut are sleeved on the threaded structure, the first nut is arranged above the connecting piece, and the second nut is arranged below the connecting piece. The height of the sucker 6.3.3 is adjusted by adjusting the positions of the first nut and the second nut, so that the sucker component can be tightly attached to the upper surface of the plate, and the sucker component can be suitable for grabbing of plates with different thicknesses. Because sucking disc 6.3.3's in this application height-adjustable, the laser cutting device of ability automatic unloading in this application is applicable to the steel of different thickness. The connecting piece comprises a connecting part and a mounting part; connecting portion are cylindrical, the installation department is the cuboid be provided with the installation department through-hole on the installation department, the telescopic link body passes the installation department through-hole. The connecting portion pass spring telescopic link mount pad through-hole, then pass respectively through the retaining member lock behind the screw thread through-hole on spring telescopic link mount pad left side and the spring telescopic link mount pad right side, thereby will connecting portion with 6.3.5 fixed connection of spring telescopic link mount pad.
A plurality of blanking mechanism connecting seats 6.6 are further arranged on the transverse circular tube 6.1, and the blanking mechanism connecting seats 6.6 are fixedly connected with the blanking lifting shaft 4.4, so that the gripper mechanism 6 is fixedly connected with the blanking mechanism 4.
The blanking mechanism connecting seat 6.6 comprises a blanking mechanism connecting seat horizontal part 6.6.1 and a blanking mechanism connecting seat vertical part 6.6.2, the blanking mechanism connecting seat horizontal part 6.6.1 is fixedly connected with the transverse round pipe 6.1, the blanking mechanism connecting seat vertical part 6.6.2 is perpendicular to the blanking mechanism connecting seat horizontal part 6.6.1, and a connecting hole is formed in the blanking mechanism connecting seat vertical part 6.6.2 and used for being installed with the blanking lifting shaft 4.4. The blanking mechanism connecting seat 6.6 further comprises a reinforcing rib 6.6.3, the cross section of the reinforcing rib 6.6.3 is a right triangle, one side of the right triangle is fixedly connected with the horizontal part 6.6.1 of the blanking mechanism connecting seat, and the other side of the right triangle is fixedly connected with the vertical part 6.6.2 of the blanking mechanism connecting seat. The purpose of the reinforcing rib 6.6.3 is to reinforce the strength of the whole blanking mechanism connecting seat 6.6.
The utility model provides a laser cutting device of automatic unloading of ability degree of automation is high to but every process independent operation can integrate into a complete production line simultaneously again and produce, and processing flexibility is high, and the opening is good.
It is right above that the utility model provides a laser cutting device's of automatic unloading embodiment has explained in detail. The principles and embodiments of the present invention have been explained herein using specific examples, and the above descriptions of the embodiments are only used to help understand the core concepts of the present invention. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, the present invention can also make several improvements and modifications, and these improvements and modifications also fall into the protection scope of the claims of the present invention.