阅读说明：本技术 一种环保降解塑料袋生产用断切装置 (Cutting device is used in production of environmental protection degradation plastic bag ) 是由 王元威 于 2021-09-02 设计创作，主要内容包括：本发明涉及环保科技技术领域,且公开了一种环保降解塑料袋生产用断切装置,包括外壳、刀座、断切机构、驱动机构、下压机构、上压机构,所述外壳中部内壁固定连接有刀座,外壳中部内壁活动连接有断切机构,外壳中部内壁活动连接有驱动机构,外壳中部内壁活动连接有下压机构,外壳中部内壁活动连接有上压机构。该环保降解塑料袋生产用断切装置,通过驱动机构带动定长机构转动,定长机构带动下压机构运行,再通过外壳与上压机构的配合使用,从而到达定长测量和快速夹持待裁剪塑料袋的效果,当定长机构旋转一周后达到所要裁剪的长度,下压机构与上压机构相互贴合从而将塑料袋进行夹持,与传统设备相比较有效的防止了塑料袋的凹陷。(The invention relates to the technical field of environmental protection science and technology, and discloses a cutting device for producing an environment-friendly degradable plastic bag. This disconnected cutting device is used in production of environmental protection degradation plastic bag, it rotates to drive length fixing mechanism through actuating mechanism, length fixing mechanism drives the operation of pushing down the mechanism, the rethread shell uses with the cooperation of last pushing down the mechanism, thereby reach the fixed length and measure and wait to cut the effect of plastic bag with quick centre gripping, reach the length that will tailor after the rotatory a week of length fixing mechanism, thereby pushing down the mechanism and last pushing down the mechanism and laminating each other and carry out the centre gripping with the plastic bag, compare the effectual sunken of preventing the plastic bag with traditional equipment.)

1. The utility model provides an environmental protection degradation plastic bag production is with disconnected cutting device which characterized in that: including shell (1), blade holder (2), disconnected cutting mechanism (3), actuating mechanism (5), pushing down mechanism (6), last pushing down mechanism (7), shell (1) middle part inner wall fixedly connected with blade holder (2), shell (1) middle part inner wall swing joint has disconnected cutting mechanism (3), shell (1) middle part inner wall swing joint has actuating mechanism (5), shell (1) middle part inner wall swing joint has pushing down mechanism (6), shell (1) middle part inner wall swing joint has last pushing down mechanism (7), fixed length mechanism (4) and pushing down mechanism (6) electric connection, go up pushing down mechanism (7) and disconnected cutting mechanism (3) electric connection.

2. The cutting device for producing the environment-friendly degradable plastic bag according to claim 1, wherein the cutting device comprises: the device is characterized by further comprising a length fixing mechanism (4), wherein the length fixing mechanism (4) is movably connected to the inner wall of the middle of the shell (1).

3. The cutting device for producing the environment-friendly degradable plastic bag according to claim 2, wherein the cutting device comprises: fixed length mechanism (4) are including winding up roller (41), dead axle (42), reset spring (43), resistance card (44), shell (1) middle part inner wall fixedly connected with dead axle (42), dead axle (42) outside swing joint has winding up roller (41), dead axle (42) middle part inner wall fixedly connected with reset spring (43), dead axle (42) middle part inner wall fixedly connected with resistance card (44).

4. The cutting device for producing the environment-friendly degradable plastic bag according to claim 3, wherein the cutting device comprises: fixed length mechanism (4) still include and lead electrical pillar (45), lug (46), flexible piece (47), piezo-resistor (48), lug (46) have been seted up to winding up roller (41) middle part inner wall, dead axle (42) middle part inner wall swing joint has flexible piece (47), and flexible piece (47) front fixedly connected with leads electrical pillar (45), flexible piece (47) middle part inner wall fixedly connected with piezo-resistor (48).

5. The cutting device for producing the environment-friendly degradable plastic bag according to claim 1, wherein the cutting device comprises: the cutting mechanism (3) comprises a magnetic block (31), an extension spring (32), a switch I (33), a cutter (34) and an electromagnet I (35), wherein the extension spring (32) is fixedly connected to the inner wall of the middle of the shell (1), the cutter (34) is fixedly connected to the bottom of the extension spring (32), the switch I (33) is movably connected to the top of the cutter (34), the magnetic block (31) is fixedly connected to the inner wall of the middle of the shell (1), and the electromagnet I (35) is fixedly connected to the inner wall of the middle of the cutter (34).

6. The cutting device for producing the environment-friendly degradable plastic bag according to claim 1, wherein the cutting device comprises: the driving mechanism (5) comprises a driving wheel (51), a second reset spring (52), a second electromagnet (53), a driving shaft (54), a movable groove (55) and a magnetic clamping block (56), wherein the driving shaft (54) is movably connected to the inner wall of the middle of the shell (1), the driving wheel (51) is movably connected to the outer side of the driving shaft (54), the movable groove (55) is formed in the inner wall of the middle of the driving wheel (51), the magnetic clamping block (56) is movably connected to the inner wall of the movable groove (55), the second reset spring (52) is fixedly connected to the outer side of the magnetic clamping block (56), and the second electromagnet (53) is fixedly connected to the inner wall of the middle of the driving shaft (54).

7. The cutting device for producing the environment-friendly degradable plastic bag according to claim 1, wherein the cutting device comprises: push down mechanism (6) including flexible groove (61), briquetting (62), switch two (63), reset spring three (64), electro-magnet one (65), flexible groove (61) have been seted up to shell (1) middle part inner wall, and flexible groove (61) middle part inner wall swing joint has briquetting (62) down, and briquetting (62) top fixedly connected with reset spring three (64) down, briquetting (62) middle part inner wall fixedly connected with electro-magnet one (65) down, briquetting (62) top swing joint has switch two (63).

8. The cutting device for producing the environment-friendly degradable plastic bag according to claim 1, wherein the cutting device comprises: go up pressure mechanism (7) including piezoelectric crystal (71), second (72) of piezo-resistor, go up briquetting (73), second (74) of electro-magnet, reset spring four (75), shell (1) middle part inner wall swing joint has last briquetting (73), goes up briquetting (73) bottom fixedly connected with reset spring four (75), goes up briquetting (73) middle part inner wall fixedly connected with electro-magnet two (74), goes up briquetting (73) middle part inner wall fixedly connected with second (72) of piezo-resistor, goes up briquetting (73) middle part inner wall fixedly connected with piezoelectric crystal (71).

Technical Field

The invention relates to the technical field of environmental protection science and technology, in particular to a cutting device for producing an environmental protection degradation plastic bag.

Background

As a product frequently used in daily life, the plastic bag is extremely large in usage amount, and in the actual use process, the plastic bag is often required to be replaced after being used once, so that a large amount of plastic garbage is generated, and the plastic garbage is not degradable in the actual treatment process, so that the living environment is greatly polluted, and along with the proposal of environmental protection, the degradable plastic bag gradually appears in our life.

Degradable plastic bag need carry out disconnected processing to it before production is sold, in order to make the consumer possess good experience, when carrying out the breakpoint processing, when cutting out the sword and tailor the plastic bag downwards, can produce a decurrent pressure to the plastic bag, and can undercut and take place to remove after the plastic bag atress to the position that makes the plastic bag tailor changes, and then leads to the length that tailors the plastic bag differs and even the breakpoint appears not thoroughly, thereby influences off-the-shelf quality.

Therefore, we propose a cutting device for the production of environment-friendly degradable plastic bags to solve the above problems.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides the cutting-off device for producing the environment-friendly degradable plastic bag, which has the advantages of simple operation, fixed-length breaking points, and prevention of sinking and incomplete power failure caused by cutting, and solves the problem of incomplete cutting of the plastic bag sinking caused by cutting of the traditional equipment.

(II) technical scheme

In order to realize the purposes of simple operation, fixed length breakpoint and prevention of sinking and incomplete power failure caused by cutting, the invention provides the following technical scheme: the utility model provides an environmental protection degradation plastic bag production is with disconnected device of cutting, includes shell, blade holder, disconnected mechanism of cutting, actuating mechanism, pushing down the mechanism, goes up the hold-down mechanism, shell middle part inner wall fixedly connected with blade holder, shell middle part inner wall swing joint have disconnected mechanism of cutting, shell middle part inner wall swing joint has actuating mechanism, shell middle part inner wall swing joint has pushing down the mechanism, and fixed length mechanism and pushing down mechanism electric connection go up the hold-down mechanism and construct electric connection with disconnected.

Further, still include fixed length mechanism, shell middle part inner wall swing joint has fixed length mechanism, and fixed length mechanism mainly plays and carries out quantitative measurement's effect to the plastic bag, makes the length of the plastics of cutting unified.

Further, fixed length mechanism includes winding up roller, dead axle, reset spring one, resistance card, shell middle part inner wall fixedly connected with dead axle, dead axle outside swing joint has the winding up roller, dead axle middle part inner wall fixedly connected with reset spring one, dead axle middle part inner wall fixedly connected with resistance card, and the length of reset spring one is less than the length of flexible piece, a reset spring top and flexible piece bottom fixed connection, the winding up roller middle part set up with the shaft hole of dead axle looks adaptation.

Furthermore, the length-fixing mechanism also comprises a conductive column, a convex block, a telescopic block and a piezoresistor I, wherein the inner wall of the middle part of the winding roller is provided with the convex block, the inner wall of the middle part of the dead axle is movably connected with the telescopic block, the front surface of the telescopic block is fixedly connected with the conductive column, the inner wall of the middle part of the telescopic block is fixedly connected with the piezoresistor I, the back surface of the conductive column is attached to the front surface of the resistor disc, the conductive column is electrically connected with the piezoresistor I, when the circuit voltage is less than the working voltage of the piezoresistor I, the piezoresistor I is in an open circuit state, when the circuit voltage is greater than the working voltage of the piezoresistor I, the piezoresistor I is in a closed circuit state, the piezoresistor I is electrically connected with an electromagnet I and an electromagnet II, wherein the electromagnet II is opposite to the magnetic pole on the inner side of the electromagnet I, the conductive column is in the maximum effective contact length with the resistor I, namely the maximum resistance value, so that the voltage passing through the conductive column is minimum and does not reach the maximum open circuit voltage of the piezoresistor I, the circuit is in an open state.

Further, the cutting mechanism comprises a magnetic block, an extension spring, a first switch, a cutter and a first electromagnet, the extension spring is fixedly connected to the inner wall of the middle of the shell, the cutter is fixedly connected to the bottom of the extension spring, the top of the cutter is movably connected with the first switch, the magnetic block is fixedly connected to the inner wall of the middle of the shell, the first electromagnet is fixedly connected to the inner wall of the middle of the cutter, the magnetic pole at the bottom of the magnetic block is the same as the magnetic pole at the top of the first electromagnet, the initial state of the first switch is a closed state, the extension spring is stretched when the cutter is subjected to a magnetic field to generate repulsive force, the first switch is in an open circuit state, the magnetic block is electrically connected with a second piezoresistor, and the second piezoresistor mainly plays a role in controlling the open circuit state of the magnetic block.

Further, actuating mechanism includes the action wheel, reset spring two, electromagnet two, the driving shaft, the activity groove, the magnetism fixture block, shell middle part inner wall swing joint has the driving shaft, driving shaft outside swing joint has the action wheel, action wheel middle part inner wall has seted up the activity groove, activity inslot inner wall swing joint has the magnetism fixture block, magnetism fixture block outside fixedly connected with reset spring two, driving shaft middle part inner wall fixedly connected with electromagnet two, the initial condition of magnetism fixture block is in and drives the shaft meshing state, the driving shaft rotates under the drive of external motor, the operating voltage of motor is 12V, power is 20W, reset spring two is in tensile state, the magnetic pole in the two outsides of electromagnet is the same with the inboard magnetic pole of magnetism fixture block, switch two mainly plays control electromagnet two outage states, switch one also plays control electromagnet two outage states.

Further, the mechanism of pushing down includes flexible groove, briquetting, switch two, reset spring three, electro-magnet one, flexible groove has been seted up to shell middle part inner wall, flexible groove middle part inner wall swing joint has briquetting down, briquetting top fixedly connected with reset spring three down, briquetting middle part inner wall fixedly connected with electro-magnet one down, briquetting top swing joint has switch two down, the briquetting is laminated with last briquetting under electro-magnet one and the drive of electro-magnet two down, thereby reach the effect that carries out the centre gripping fastening to the plastic bag, reset spring three's length is less than the length of briquetting down, three tops of reset spring and flexible inslot roof fixed connection, the initial length of reset spring three is in the original length.

Further, the upper pressing mechanism comprises a piezoelectric crystal, a second piezoresistor, an upper pressing block, a second electromagnet and a fourth reset spring, the inner wall of the middle part of the shell is movably connected with the upper pressing block, the bottom of the upper pressing block is fixedly connected with the fourth reset spring, the inner wall of the middle part of the upper pressing block is fixedly connected with the second piezoresistor, the inner wall of the middle part of the upper pressing block is fixedly connected with the piezoelectric crystal, when the circuit voltage is less than the working voltage of the second piezoresistor, the second piezoresistor is in an open circuit state, when the circuit voltage is greater than the working voltage of the second piezoresistor, the second piezoresistor is in an open circuit state, so that the circuit is in an open circuit state, the magnetic block is electrified to generate a magnetic field, when the upper pressing block and the lower pressing block are mutually attached under the attraction of the second electromagnet and the first electromagnet, so that the piezoelectric crystal is impacted and generates voltage, and because the piezoelectric crystal can generate voltage when being impacted, the piezoelectric crystal belongs to the physical property of itself, therefore, the voltage passing through the second piezoresistor reaches the working voltage of the second piezoresistor, so that the circuit is in a path state.

(III) advantageous effects

Compared with the prior art, the invention provides the cutting device for producing the environment-friendly degradable plastic bag, which has the following beneficial effects:

1. this disconnected cutting device is used in production of environmental protection degradation plastic bag, it rotates to drive length fixing mechanism through actuating mechanism, length fixing mechanism drives the operation of pushing down the mechanism, the rethread shell uses with the cooperation of last pushing down the mechanism, thereby reach the fixed length and measure and wait to cut the effect of plastic bag with quick centre gripping, reach the length that will tailor after the rotatory a week of length fixing mechanism, thereby pushing down the mechanism and last pushing down the mechanism and laminating each other and carry out the centre gripping with the plastic bag, compare the effectual sunken of preventing the plastic bag with traditional equipment.

2. This disconnected device of cutting is used in production of environmental protection degradation plastic bag, through the operation of length fixing mechanism belt bottom load mechanism, length fixing mechanism drives the operation of last hold-down mechanism, and the cooperation of rethread disconnected mechanism and blade holder is used to reach the effect that cuts automatically, thereby because the laminating of hold-down mechanism and last hold-down mechanism produces the striking in the twinkling of an eye and triggers disconnected mechanism circular telegram, cuts the plastic bag of centre gripping.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a partially enlarged view of the portion A of FIG. 1 according to the present invention;

FIG. 3 is a partially enlarged view of the portion B shown in FIG. 1 according to the present invention;

FIG. 4 is a cross-sectional view of a length control mechanism of the present invention;

fig. 5 is a schematic cross-sectional view of the drive mechanism of the present invention.

In the figure: 1. a housing; 2. a tool apron; 3. a cutting mechanism; 4. a length fixing mechanism; 5. a drive mechanism; 6. a pressing mechanism; 7. a pressing mechanism; 31. a magnetic block; 32. an extension spring; 33. a first switch; 34. a cutter; 35. a first electromagnet; 41. a winding roller; 42. fixing a shaft; 43. a first return spring; 44. resistance cards; 45. a conductive post; 46. a bump; 47. a telescopic block; 48. a first voltage dependent resistor; 51. a driving wheel; 52. a second return spring; 53. a second electromagnet; 54. a drive shaft; 55. a movable groove; 56. a magnetic fixture block; 61. a telescopic groove; 62. pressing the block; 63. a second switch; 64. a third return spring; 65. an electromagnet I; 71. a piezoelectric crystal; 72. a second voltage dependent resistor; 73. pressing the blocks; 74. an electromagnet II; 75. and a fourth return spring.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The first embodiment is as follows:

referring to fig. 1-5, a cutting device for producing an environmentally-friendly degradable plastic bag comprises a housing 1, a tool apron 2, a cutting mechanism 3, the cutting mechanism 3 comprises a magnet 31, an extension spring 32, a first switch 33, a cutter 34 and a first electromagnet 35, the inner wall of the middle part of the housing 1 is fixedly connected with the extension spring 32, the bottom of the extension spring 32 is fixedly connected with the cutter 34, the top of the cutter 34 is movably connected with the first switch 33, the inner wall of the middle part of the housing 1 is fixedly connected with the magnet 31, the inner wall of the middle part of the cutter 34 is fixedly connected with the first electromagnet 35, the magnetic pole at the bottom of the magnet 31 is the same as the magnetic pole at the top of the first electromagnet 35, the initial state of the first switch 33 is a closed state, when the cutter 34 is subjected to a magnetic field to generate a repulsive force, the extension spring 32 is stretched, so that the first switch 33 is in an open circuit state, the magnet 31 is electrically connected with a second varistor 72, the second varistor 72 mainly controls the open circuit state of the magnet 31, the driving mechanism 5, the pressing mechanism 6 and the pressing mechanism 6 comprise a telescopic groove 61, a pressing block 62, a switch II 63, a return spring III 64 and an electromagnet I65, the inner wall of the middle part of the shell 1 is provided with the telescopic groove 61, and the inner wall of the middle part of the telescopic groove 61 is movably connected with the pressing block 62;

the top of the lower pressing block 62 is fixedly connected with a return spring III 64, the inner wall of the middle part of the lower pressing block 62 is fixedly connected with an electromagnet I65, the top of the lower pressing block 62 is movably connected with a switch II 63, the lower pressing block 62 is attached to an upper pressing block 73 under the driving of the electromagnet I65 and the electromagnet II 74, so that the effect of clamping and fastening the plastic bag is achieved, the length of the return spring III 64 is smaller than that of the lower pressing block 62, the top of the return spring III 64 is fixedly connected with the top wall of the telescopic groove 61, the initial length of the return spring III 64 is in the original length, the upper pressing mechanism 7, the inner wall of the middle part of the shell 1 is fixedly connected with a knife holder 2, the inner wall of the middle part of the shell 1 is movably connected with a cutting mechanism 3, the inner wall of the middle part of the shell 1 is movably connected with a driving mechanism 5, the inner wall of the middle part of the shell 1 is movably connected with a lower pressing mechanism 6, the inner wall of the middle part of the shell 1 is movably connected with the upper pressing mechanism 7, and the length-fixing mechanism 4 is electrically connected with the lower pressing mechanism 6, the pressing mechanism 7 is electrically connected with the cutting mechanism 3.

Example two:

referring to fig. 1-5, a cutting device for producing an environmentally-friendly degradable plastic bag comprises a housing 1, a tool apron 2, a cutting mechanism 3, the cutting mechanism 3 comprises a magnet 31, an extension spring 32, a first switch 33, a cutter 34 and a first electromagnet 35, the inner wall of the middle part of the housing 1 is fixedly connected with the extension spring 32, the bottom of the extension spring 32 is fixedly connected with the cutter 34, the top of the cutter 34 is movably connected with the first switch 33, the inner wall of the middle part of the housing 1 is fixedly connected with the magnet 31, the inner wall of the middle part of the cutter 34 is fixedly connected with the first electromagnet 35, the magnetic pole at the bottom of the magnet 31 is the same as the magnetic pole at the top of the first electromagnet 35, the initial state of the first switch 33 is a closed state, when the cutter 34 is subjected to a magnetic field to generate a repulsive force, the extension spring 32 is stretched, so that the first switch 33 is in an open circuit state, the magnet 31 is electrically connected with a second varistor 72, the second varistor 72 mainly controls the open circuit state of the magnet 31, the length-fixing mechanism 4 and the length-fixing mechanism 4 comprise a winding roller 41, a fixed shaft 42, a first return spring 43 and a resistor disc 44, the fixed shaft 42 is fixedly connected to the inner wall of the middle part of the shell 1, the outer side of the fixed shaft 42 is movably connected with the winding roller 41, the first return spring 43 is fixedly connected to the inner wall of the middle part of the fixed shaft 42, the resistor disc 44 is fixedly connected to the inner wall of the middle part of the fixed shaft 42, the length of the first return spring 43 is smaller than that of the telescopic block 47, the top of the first return spring 43 is fixedly connected with the bottom of the telescopic block 47, a shaft hole matched with the fixed shaft 42 is formed in the middle part of the winding roller 41, the length-fixing mechanism 4 further comprises a conductive column 45, a convex block 46, the telescopic block 47 and a first piezoresistor 48, and the convex block 46 is formed in the inner wall of the middle part of the winding roller 41;

the inner wall of the middle part of the fixed shaft 42 is movably connected with a telescopic block 47, the front surface of the telescopic block 47 is fixedly connected with a conductive column 45, the inner wall of the middle part of the telescopic block 47 is fixedly connected with a piezoresistor I48, the back surface of the conductive column 45 is attached to the front surface of the resistor disc 44, the conductive column 45 is electrically connected with the piezoresistor I48, when the circuit voltage is less than the operating voltage of the first varistor 48, the first varistor 48 is in an open circuit state, when the circuit voltage is greater than the working voltage of the first voltage dependent resistor 48, the first voltage dependent resistor 48 is in a closed state, the first voltage dependent resistor 48 is electrically connected with the first electromagnet 65 and the second electromagnet 74, wherein the magnetic poles of the second electromagnet 74 are opposite to the magnetic poles of the first electromagnet 65, the effective contact length of the conductive column 45 and the resistance sheet 44 is the largest, that is, the resistance value is the largest, therefore, the voltage passing through the conductive column 45 is minimum, the maximum access voltage of the first piezoresistor 48 is not reached, and the circuit is in an open circuit state;

the driving mechanism 5 and the driving mechanism 5 comprise a driving wheel 51, a second return spring 52, a second electromagnet 53, a driving shaft 54, a movable groove 55 and a magnetic clamping block 56, the driving shaft 54 is movably connected to the inner wall of the middle part of the shell 1, the driving wheel 51 is movably connected to the outer side of the driving shaft 54, the movable groove 55 is formed in the inner wall of the middle part of the driving wheel 51, the magnetic clamping block 56 is movably connected to the inner wall of the movable groove 55, the second return spring 52 is fixedly connected to the outer side of the magnetic clamping block 56, the second electromagnet 53 is fixedly connected to the inner wall of the middle part of the driving shaft 54, the initial state of the magnetic clamping block 56 is in a state of being meshed with the driving shaft 54, the driving shaft 54 is driven by an external motor to rotate, the working voltage of the motor is 12V, the power is 20W, the second return spring 52 is in a stretching state, the magnetic poles on the outer sides of the second electromagnets 53 are the same as the magnetic poles on the inner side of the magnetic clamping block 56, and the second switch 63 mainly plays a role in controlling the on-off state of the second electromagnet 53, the first switch 33 also serves to control the on/off state of the second electromagnet 53,

the pressing mechanism 6 and the pressing mechanism 6 comprise a telescopic groove 61, a pressing block 62, a switch II 63, a return spring III 64 and an electromagnet I65, the inner wall of the middle part of the shell 1 is provided with the telescopic groove 61, the inner wall of the middle part of the telescopic groove 61 is movably connected with the pressing block 62, the top of the pressing block 62 is fixedly connected with the return spring III 64, the inner wall of the middle part of the pressing block 62 is fixedly connected with the electromagnet I65, the top of the pressing block 62 is movably connected with the switch II 63, the pressing block 62 is attached to the pressing block 73 under the driving of the electromagnet I65 and the electromagnet II 74, so that the effect of clamping and fastening the plastic bag is achieved, the length of the return spring III 64 is smaller than that of the pressing block 62, the top of the return spring III 64 is fixedly connected with the top wall in the telescopic groove 61, the initial length of the return spring III 64 is in the original length, the pressing mechanism 7 comprises a piezoelectric crystal 71, a piezoresistor II 72, and the pressing block 73, The inner wall of the middle part of the shell 1 is movably connected with an upper pressing block 73, the bottom of the upper pressing block 73 is fixedly connected with a fourth reset spring 75, the inner wall of the middle part of the upper pressing block 73 is fixedly connected with a second electromagnet 74, the inner wall of the middle part of the upper pressing block 73 is fixedly connected with a second piezoresistor 72, the inner wall of the middle part of the upper pressing block 73 is fixedly connected with a piezoelectric crystal 71, when the circuit voltage is smaller than the working voltage of the second piezoresistor 72, the second piezoresistor 72 is in an open circuit state, and when the circuit voltage is larger than the working voltage of the second piezoresistor 72, the second piezoresistor 72 is in an open circuit state, so that the circuit is in an open circuit state;

the magnetic block 31 is electrified to generate a magnetic field, when the upper pressing block 73 and the lower pressing block 62 are mutually attached under the attraction of the electromagnet II 74 and the electromagnet I65, the piezoelectric crystal 71 is impacted and generates voltage, because the piezoelectric crystal 71 can generate voltage when being impacted, the voltage belongs to the physical property of the piezoelectric crystal, the voltage of the piezoresistor II 72 reaches the working voltage of the piezoresistor II 72, so that the circuit is in a closed circuit state, the inner wall of the middle part of the shell 1 is fixedly connected with the tool apron 2, the inner wall of the middle part of the shell 1 is movably connected with the cutting mechanism 3, the inner wall of the middle part of the shell 1 is movably connected with the driving mechanism 5, the inner wall of the middle part of the shell 1 is movably connected with the lower pressing mechanism 6, the inner wall of the middle part of the shell 1 is movably connected with the upper pressing mechanism 7, the length fixing mechanism 4 is electrically connected with the lower pressing mechanism 6, and the upper pressing mechanism 7 is electrically connected with the cutting mechanism 3,

the working principle is as follows: one end of the plastic bag to be cut is fixedly connected with the outer side of the winding roller 41, the driving shaft 54 is driven to rotate clockwise by an external motor, the initial state of the electromagnet 53 is in a passage state, so that the magnetic clamping block 56 is meshed with the driving shaft 54 to drive the driving wheel 51 to rotate, the winding roller 41 rotates along the outer side of the fixed shaft 42 and drives the lug 46 to rotate under the action of the driving wheel 51, after the winding roller 41 rotates for a circle, the lug 46 is contacted with the telescopic block 47 and extrudes the telescopic block 47 downwards, the movement of the telescopic block 47 drives the conductive column 45 to move, so that the effective contact length of the conductive column 45 and the resistor sheet 44 is shortened, when the telescopic block 47 moves to the maximum limit, the effective contact length of the conductive column 45 and the resistor sheet 44 is shortest, the voltage passing through the conductive column 45 is increased, the voltage passing through the piezoresistor 48 is increased, so that the piezoresistor 48 is in a passage state, the electromagnet I65 and the electromagnet II 74 are electrified to generate a magnetic field, and the magnetic poles of the electromagnet I65 and the magnetic poles of the electromagnet II 74 are opposite to each other, so that the electromagnet I65 and the electromagnet II 74 are attracted mutually;

so that the lower pressing block 62 is attached to the upper pressing block 73 to clamp and fasten the plastic bag, at the same time, the return spring three 64 and the return spring four 75 are stretched, so that the switch two 63 is in an open circuit state, at the same time, the electromagnet two 53 is in an open circuit state, the attractive force on the magnetic clamping block 56 disappears, at the same time, the action of the return spring two 52 moves outwards along the inner wall of the movable groove 55 and is separated from the driving shaft 54, so that the driving wheel 51 stops rotating, when the upper pressing block 73 and the lower pressing block 62 are attached to each other under the attraction of the electromagnet two 74 and the electromagnet one 65, so that the piezoelectric crystal 71 is impacted and generates voltage, the voltage of the piezoresistor two 72 reaches the working voltage of the piezoresistor two 72 to enable the circuit to be in a closed state, the magnetic block 31 is electrified to generate a magnetic field, so that the electromagnet one 35 is subjected to the repulsive force to drive the cutter 34 to move downwards, and the stretching spring 32 is stretched, so as to attach the cutter 34 to the cutter holder 2, thereby achieving the effect of cutting;

because under the clamping of the lower pressing block 62 and the upper pressing block 73, the plastic bag is not sunken to cause the phenomenon of over-cutting or incomplete cutting, when the cutting is finished, the impact force applied to the piezoelectric crystal 71 disappears, the voltage passing through the second piezoresistor 72 is zero, so that the magnetic block 31 is powered off, the repulsive force applied to the first electromagnet 35 disappears, the cutter 34 is driven to move upwards under the stretching of the stretching spring 32, the first switch 33 is in a closed state when the cutter 34 is restored to the maximum position, so that the second electromagnet 53 is in a closed state again, the magnetic clamping block 56 is attracted, the driving wheel 51 is driven to rotate again, the winding roller 41 is driven to rotate by the rotation of the driving wheel 51 to separate the convex block 46 from the telescopic block 47, at the moment, the telescopic block 47 is restored to the initial state under the action of the first return spring 43, and the conductive post 45 is driven to move upwards by the movement of the telescopic block 47, the effective contact length of the conductive column 45 and the resistance sheet 44 is increased, so that the voltage passing through the conductive column 45 is reduced, at the moment, the voltage passing through the first piezoresistor 48 is reduced, so that the first piezoresistor 48 is in an open circuit state, the first electromagnet 65 and the second electromagnet 74 are powered off, the mutual attraction force disappears, the upper pressing block 73 and the lower pressing block 62 are restored to the initial positions under the stretching of the fourth return spring 75 and the third return spring 64, and the plastic bag is wound by the winding roller 41.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.