Plastic fragment granulating device with multi-stage screening function

Abstract

The invention discloses a plastic fragment granulating device with a multi-stage screening function, and relates to the technical field of plastic waste recycling. Comprising a machine shell, a motor, a shearing roller, a guide roller, a traction roller and a supporting table, an annular groove of a traction wheel and the supporting table jointly form a bidirectional limiting structure for clamping a strip-shaped material up and down, so that the strip-shaped material cannot transversely deviate or jump out of the groove or swing in the traction process, and it is guaranteed that the strip-shaped material enters a shearing area along a set rail. The anti-skid lines are arranged in the annular grooves, the friction force between the wet strip-shaped materials and the traction wheel can be effectively enhanced, the problems of slipping, insufficient traction force and the like caused by a water film on the wet surface are solved, and it is guaranteed that the strip-shaped materials are stably and continuously pulled to the shearing position. After releasing is finished, the electromagnet is powered off, the sliding column and the occlusion plate are reset under the action of the second spring, the occlusion teeth are meshed with the connecting column again, the traction wheel is driven again to recover traction, manual intervention is not needed, normal granulation can be rapidly recovered, and continuous plastic recovery and regeneration are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plastic waste recycling, and particularly relates to a granulating device for plastic fragments with multi-stage screening function. BACKGROUND

[0002] The granulating device is a key equipment in the field of plastic waste recycling, which can cut the renewable plastic melt or solid rod into uniform particles. The device is usually composed of extrusion, cooling, traction and cutting units. After the waste is melted and extruded into a rod, it enters the cutting mechanism under the action of cooling and conveying, and is cut by a rotating cutter according to the set length, so that the renewable plastic particles for storage and reprocessing are finally obtained.

[0003] However, the rod-shaped material extruded by the extrusion device is prone to slipping, deviation or jumping during wet traction due to the surface water film, so that stable guidance and effective traction are difficult to achieve. When the effective length of a rod-shaped material is shortened due to cooling shrinkage or bending accumulation, the tension of the channel where the rod-shaped material is located will increase sharply. The existing traction structure usually still maintains forced traction, and cannot automatically disconnect or unload when the tension reaches the dangerous interval, so that the rod-shaped material is prone to excessive stretching, breaking or plastic deformation under the action of high tension, thereby affecting the granulation quality and production stability. SUMMARY

[0004] The present application aims to provide a granulating device for plastic fragments with multi-stage screening function to solve the problems in the prior art.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a granulating device for plastic fragments with multi-stage screening function, comprising a machine shell, a motor is installed on the machine shell, a shearing roller is rotatably installed on the machine shell, one end of the shearing roller is connected with the output shaft of the motor through a belt pulley, a traction roller is rotatably installed on the machine shell, the traction roller is in meshing transmission with the shearing roller, a support table is installed in the machine shell, the support table is located below the traction roller, and a guide roller is rotatably installed in the machine shell. The traction roller comprises a roller body rotatably installed on the machine shell, and a plurality of disc-shaped traction devices are installed on the roller body.

[0006] A control system is installed in the machine shell, and the control system is used for controlling the entire granulating device. The granulating device is connected with a screening mechanism.

[0007] In operation, the plastic fragments are melted and continuously extruded into a plurality of rod-shaped melt strips by the extrusion device, the plurality of rod-shaped melts are synchronously introduced into a water tank arranged behind the extrusion end, the rod-shaped melts are cooled by the water tank to solidify and form stable rod-shaped materials. The plurality of rod-shaped materials cooled by the water tank enter the guide roller, the guide roller preliminarily positions and guides the rod-shaped materials, and then the rod-shaped materials enter the traction roller.

[0008] Meanwhile, the control system starts the motor, the motor output shaft drives the shearing roller to rotate through the belt pulley, the shearing roller drives the first gear to rotate, the first gear drives the second gear meshing therewith to rotate, and the second gear subsequently drives the traction roller to rotate, thereby realizing double driving of the shearing roller and the traction roller.

[0009] The traction roller drives the several parallel strip materials to enter the shearing area composed of the supporting table and the traction roller synchronously, the downward rotating roller cutter on the shearing roller is relatively dislocated with the edge of the supporting table, a shearing action is generated, a shearing force is generated on the strip material exceeding the edge of the supporting table, the exceeding part is sheared into small particles, and granulation is completed.

[0010] The small particles are sheared and then fall into the hopper under their own gravity, finally fall into the collecting box at the bottom of the hopper, are further transported to the screening mechanism through the conveying device after drying treatment, and the screening mechanism performs multi-stage screening treatment on the granules.

[0011] Further, the disc-shaped traction device comprises a side disc, a traction wheel is rotatably installed on the side disc, a plurality of tension releasing mechanisms are installed in the side disc, a plurality of connecting columns are arranged on the roller body, the side disc is rotatably installed on the connecting columns, the side disc is engaged with the connecting columns through the tension releasing mechanisms, and a plurality of tension detecting mechanisms are installed between the side disc and the traction wheel.

[0012] Further, an outer ring is arranged on the side disc, a force transmission block is arranged on the outer ring, an inner ring is arranged on the side disc, the tension releasing mechanisms are installed on the inner ring, the tension detecting mechanisms are installed between the force transmission block and the traction wheel, and the inner ring is rotatably installed on the connecting columns.

[0013] Further, the tension releasing mechanism comprises a sliding column and an electromagnet, the sliding column is slidably installed on the inner ring, one end of the sliding column is provided with an engagement plate, a plurality of engagement teeth are arranged on the engagement plate, a plurality of engagement grooves are uniformly arranged on the connecting columns, the engagement teeth are embedded in the engagement grooves, a second spring is installed between the engagement plate and the inner ring, the electromagnet is installed on the inner wall of the outer ring, the other end of the sliding column is a adsorbable end, and the electromagnet corresponds to the adsorbable end of the sliding column.

[0014] When the control system detects that the tension of the strip material exceeds the set threshold, the electromagnet is started. The electromagnet generates an adsorption force after being powered on, the adsorbable end of the sliding column is adsorbed and fixed, the sliding column moves to the electromagnet direction against the elastic force of the second spring. With the displacement of the sliding column, the second spring is compressed, the sliding column drives the engagement plate to slide on the inner ring, and the engagement teeth on the engagement plate are withdrawn from the engagement grooves. At this time, the side disc and the connecting column on the roller body are out of engagement, the side disc is in a freely rotatable state relative to the connecting column. Since there is friction between the traction wheel and the strip material, the traction wheel cannot continue to rotate with the roller body, and the traction action is immediately released.

[0015] Meanwhile, the compression force of the transmission block to the first spring disappears, the first spring automatically rebounds, and pushes the side disc to rotate reversely relative to the connecting column, to realize the releasing action, so as to quickly release the abnormally high tension of the strip material, and avoid the strip material from being broken or plastically deformed due to overloading.

[0016] During the releasing, the traction wheel remains stationary, and the strip material corresponding to the position is no longer subjected to the traction force, and the tension thereof is completely eliminated. After the releasing process ends, the control system turns off the electromagnet, so that the suction force disappears. The electromagnet is powered off to release the slide column, the second spring is reset, and the slide column is pushed back to the initial position. The slide column returns to the initial position while driving the clamping plate to slide again, so that the clamping teeth are re-embedded in the clamping groove, and the side disc is reliably clamped with the connecting column again. Subsequently, the roller body resumes driving the traction wheel, the traction wheel re-applies the traction force to the strip material, and the device returns to the normal operating state.

[0017] Further, the tension detection mechanism comprises a transmission frame installed on the inner wall of the traction wheel, an arc-shaped slide rod installed on the transmission frame, the arc-shaped slide rod being in sliding connection with the transmission block, a piezoelectric body installed on the transmission block, and a transmission sheet installed on the piezoelectric body, the first spring being installed between the transmission sheet and the transmission frame.

[0018] During the cooling process, part of the strip material may be relatively shortened due to a large shrinkage or obvious bending deformation during conveying, etc. Since the traction roller applies the traction force to the strip material through the plurality of traction wheels, when the length of the strip material is shortened, the tension of the strip material in the channel is further increased. Under the action of the increased tension, the corresponding traction wheel bears a larger reverse tension, so that the relative rotation between the traction wheel and the side disc occurs. Consequently, the transmission frame on the side disc approaches the transmission block, driving the first spring to be compressed, the elastic force of the first spring is transmitted to the piezoelectric body through the transmission sheet, so that the piezoelectric body is subjected to external pressure and outputs a corresponding electric signal. The shorter the strip material is, the greater the axial tension is, and thus the greater the relative rotation angle between the traction wheel and the side disc is, the greater the compression amount of the first spring is, and the stronger the electric signal generated by the piezoelectric body is. The control system can detect, record and determine the real-time tension state of the strip material according to the strength of the electric signal.

[0019] Further, the slide column is provided with a plurality of damping grooves, and the inner ring is provided with a plurality of convex rings at the contact position with the slide column.

[0020] The damping grooves and the convex rings cooperate to produce a damping effect, so as to slow down the sliding speed of the slide column.

[0021] Further, the traction wheel is provided with an annular groove, and the annular groove is provided with a plurality of anti-skid lines.

[0022] When the traction roller rotates, the roller body is first rotated by the second gear, and the roller body drives a plurality of disc-shaped traction devices engaged therewith to rotate.

[0023] The traction roller is provided with an annular groove, and the upper half of the strip-shaped material is embedded in the bottom of the annular groove and forms a two-way limiting structure with the lower support platform, so that the strip-shaped material cannot deviate laterally or jump in the traction process, and a two-stage limiting and guiding effect is achieved.

[0024] Further, the roller body is provided with a second gear on one side, the shearing roller is provided with a first gear on one side, the first gear is engaged with the second gear for transmission, and the housing is provided with a hopper.

[0025] Further, a plurality of roller knives are arranged on the shearing roller, and the roller knives form a shearing structure with the edge of the support platform.

[0026] When the strip-shaped material passes through the guide roller, it is embedded in the guide groove, which prevents the strip-shaped material from deviating and plays a preliminary guiding role.

[0027] Compared with the prior art, the beneficial effects of the present application are: 1. The annular groove of the traction roller and the support platform jointly form a two-way limiting structure for clamping the strip-shaped material from above and below, so that the strip-shaped material cannot deviate laterally, jump or swing in the traction process, and the strip-shaped material is ensured to enter the shearing area along the predetermined track. Anti-skid patterns are arranged inside the annular groove, which can effectively enhance the friction force between the wet strip-shaped material and the traction roller, avoid the problems of slipping and insufficient traction force caused by the water film on the wet surface, and ensure that the strip-shaped material is stably and continuously pulled to the shearing position.

[0028] 2. The tension detection mechanism converts the change in tension of the strip-shaped material into spring compression and piezoelectric signals. The shorter the strip-shaped material, the higher the tension, and the stronger the piezoelectric output signal, so as to realize real-time monitoring and determination of the tension state of the strip-shaped material and effectively identify abnormal tension conditions.

[0029] 3. When the tension of the strip-shaped material exceeds the set threshold value, the electromagnet drives the engagement plate to disengage from the connecting column, so that the side disc enters a free rotation state, and the traction roller instantaneously releases the traction effect. The side disc is driven to complete the tension release action by the rebound of the first spring, which can quickly release abnormal tension and avoid the strip-shaped material from being broken or plastically deformed due to excessive stretching, thereby greatly improving the operation reliability of the equipment.

[0030] 4. After the tensioning is completed, the electromagnet is de-energized, and the sliding column and the biting plate are reset under the action of the second spring, so that the biting teeth re-engage the connecting column, and the traction wheel is driven again to resume traction. No manual intervention is required, and normal granulation can be quickly resumed, realizing continuous plastic recycling and regeneration. Attached Figure Description

[0031] Figure 1 This is an overall perspective view of the granulation apparatus of the present invention; Figure 2 This is a perspective view of the granulation apparatus of the present invention; Figure 3 This is a cross-sectional view of the granulation apparatus of the present invention; Figure 4 This is a perspective view of the traction roller of the present invention; Figure 5 This is a perspective view of the disc-shaped traction device of the present invention; Figure 6 This is a perspective view of the traction wheel of the present invention; Figure 7 This is a cross-sectional view of the disc-shaped traction device of the present invention; Figure 8 For the present invention Figure 7 A magnified view of a portion of region A in the middle; Figure 9 For the present invention Figure 7 A magnified view of a portion of region B in the middle; Figure 10 This is a perspective view of the roller body of the present invention; Figure 11 This is a perspective view of the side disc of the present invention.

[0032] In the diagram: 1. Machine casing; 2. Motor; 3. Shearing roller; 4. Guide roller; 5. Traction roller; 6. Support platform; 31. First gear; 51. Second gear; 52. Disc-shaped traction device; 53. Roller body; 521. Traction wheel; 522. Side disc; 523. Tension detection mechanism; 524. Unloading mechanism; 5231. Force transmission frame; 5232. Arc-shaped slide bar; 5233. First spring; 5234. Pressure... Electromechanical element; 5235, force transmission plate; 5241, engagement plate; 5242, bite tooth; 5243, sliding column; 5244, second spring; 5245, damping groove; 5246, electromagnet; 531, connecting column; 5221, outer ring; 5222, inner ring; 5223, convex ring; 5224, force transmission block; 5211, annular groove; 5212, anti-slip texture; 11, funnel; 32, roller cutter. Detailed Implementation

[0033] Clearly, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present application.

[0034] As shown in the Figures 1-11 The present application provides a plastic fragment granulating device with multi-stage screening function, which comprises a casing 1, a motor 2 installed on the casing 1, a shearing roller 3 rotatably installed on the casing 1, the shearing roller 3 being in transmission connection with the output shaft of the motor 2 through a belt pulley at one end, a traction roller 5 rotatably installed on the casing 1, the traction roller 5 being in transmission with the shearing roller 3, a support table 6 installed in the casing 1 and located below the traction roller 5, and a guide roller 4 rotatably installed in the casing 1. The traction roller 5 comprises a roller body 53 rotatably installed on the casing 1, and a plurality of disc-shaped traction devices 52 installed on the roller body 53.

[0035] A control system is installed in the casing 1 and used for controlling the entire granulating device. The granulating device is externally connected with a screening mechanism.

[0036] A second gear 51 is installed on one side of the roller body 53, a first gear 31 is installed on one side of the shearing roller 3, the first gear 31 is in transmission with the second gear 51, and a hopper 11 is arranged on the casing 1.

[0037] A plurality of roller knives 32 are arranged on the shearing roller 3, the roller knives 32 form a shearing structure with the edge of the support table 6, and a plurality of guide grooves are arranged on the guide roller 4.

[0038] When the strip-shaped material passes through the guide roller 4, it will be embedded in the guide groove, the guide groove is used for preventing the strip-shaped material from deviating and plays a role of preliminary guidance.

[0039] The tension detection mechanism 523 comprises a force transmission frame 5231 installed on the inner wall of the traction wheel 521, an arc-shaped sliding rod 5232 installed on the force transmission frame 5231, the arc-shaped sliding rod 5232 being in sliding connection with a force transmission block 5224, a piezoelectric body 5234 installed on the force transmission block 5224, a force transmission sheet 5235 installed on the piezoelectric body 5234, and a first spring 5233 installed between the force transmission sheet 5235 and the force transmission frame 5231.

[0040] A plurality of damping grooves 5245 are arranged on the sliding column 5243, and a plurality of convex rings 5223 are arranged at the contact position between the inner ring 5222 and the sliding column 5243. The damping grooves 5245 and the convex rings 5223 cooperate to generate a damping effect and slow down the sliding speed of the sliding column 5243.

[0041] The disc-shaped traction device 52 comprises a side disc 522, a traction wheel 521 is rotatably installed on the side disc 522, and a plurality of tension releasing mechanisms 524 are installed in the side disc 522; a plurality of connecting columns 531 are arranged on the roller body 53, the side disc 522 is rotatably installed on the connecting columns 531, the side disc 522 is engaged with the connecting columns 531 through the tension releasing mechanisms 524, and the side disc 522 is installed between the traction wheel 521 and the tension releasing mechanisms 524.

[0042] The side disc 522 is provided with an outer ring 5221 and a plurality of transmission blocks 5224 are arranged on the outer ring 5221; the side disc 522 is provided with an inner ring 5222, the tension releasing mechanisms 524 are installed on the inner ring 5222, the tension releasing mechanisms 523 are installed between the transmission blocks 5224 and the traction wheel 521, and the inner ring 5222 is rotatably installed on the connecting columns 531.

[0043] The tension releasing mechanism 524 comprises a sliding column 5243 and an electromagnet 5246, the sliding column 5243 is slidably installed on the inner ring 5222, one end of the sliding column 5243 is provided with an engaging plate 5241, a plurality of engaging teeth 5242 are arranged on the engaging plate 5241, a plurality of engaging grooves are uniformly arranged on the connecting columns 531, the engaging teeth 5242 are engaged with the engaging grooves, a second spring 5244 is installed between the engaging plate 5241 and the inner ring 5222, the other end of the sliding column 5243 is an adsorbable end, and the electromagnet 5246 is installed on the inner wall of the outer ring 5221 and corresponds to the position of the adsorbable end of the sliding column 5243.

[0044] The traction wheel 521 is provided with an annular groove 5211, and a plurality of anti-skid lines 5212 are arranged in the annular groove 5211.

[0045] The working principle of the present application is as follows: during operation, the plastic fragments are melted and continuously extruded into a plurality of strip-shaped molten material strips by the extrusion device, the plurality of strip-shaped molten bodies are synchronously introduced into the water tank arranged behind the extrusion end, the strip-shaped molten bodies are cooled by the water tank, so that they are solidified to form stable strip-shaped materials. The plurality of strip-shaped materials cooled by the water tank are introduced into the guide roller 4, the guide roller 4 preliminarily positions and guides the strip-shaped materials, and then the strip-shaped materials are introduced into the traction roller 5.

[0046] At the same time, the control system starts the motor 2, the output shaft of the motor 2 drives the shearing roller 3 to rotate through the belt pulley, the shearing roller 3 drives the first gear 31 to rotate, the first gear 31 drives the second gear 51 meshing therewith to rotate, and then the second gear 51 drives the traction roller 5 to rotate, so that the shearing roller 3 and the traction roller 5 are driven in double.

[0047] The traction roller 5 drives the plurality of parallel strip-shaped materials to synchronously enter the shearing area composed of the supporting table 6 and the traction roller 5 by rotating, the downward rotating roller cutter 32 on the shearing roller 3 is relatively staggered with the edge of the supporting table 6, a shearing action is generated, a shearing force is generated on the strip-shaped material exceeding the edge of the supporting table 6, the exceeding part is sheared into small particles, and thus the granulation is completed.

[0048] The fine particles are cut off and fall into the hopper 11 under their own gravity, and finally fall into the collection box at the bottom of the hopper 11, and after drying treatment, are further transported to the screening mechanism by the conveying device, and the screening mechanism performs multi-stage screening treatment on the granules.

[0049] When the traction roller 5 rotates, the roller body 53 is first driven to rotate by the second gear 51, and the roller body 53 drives a plurality of disc-shaped traction devices 52 engaged therewith to rotate. Among them, the side disc 522 is driven to rotate by the connecting column 531 under the engagement of the open structure, and the transmission block 5224 on the side disc 522 is pushed outward by the first spring 5233, so that the transmission frame 5231 generates a corresponding rotation, and the transmission frame 5231 further drives the traction wheel 521 to rotate in unison. Thus, the outer edge of the traction wheel 521 exerts a stable traction force on the strip-shaped material located on the support table 6.

[0050] The outer periphery of the traction wheel 521 is provided with an annular groove 5211, and the upper half of the strip-shaped material is embedded in the bottom of the annular groove 5211 and forms a two-way limiting structure with the lower support table 6, so that the strip-shaped material cannot deviate laterally or jump in the traction process, realizing a two-stage limiting and guiding effect. The anti-slip pattern 5212 arranged in the annular groove 5211 strengthens the contact friction force between the annular groove 5211 and the wet strip-shaped material, avoiding the sliding phenomenon caused by surface water, thereby ensuring stable transmission of the traction force.

[0051] During the cooling process, part of the strip-shaped material may be relatively shortened due to a large shrinkage or obvious bending deformation during conveying, etc. Since the traction roller 5 applies a traction force to the strip-shaped material through a plurality of traction wheels 521, when the length of the strip-shaped material is shortened, the strip-shaped material in the channel where it is located is further tensioned. Under the action of the tensioning, the corresponding traction wheel 521 bears a greater reverse tensioning force, causing the relative rotation between the traction wheel 521 and the side disc 522. Consequently, the transmission frame 5231 on the side disc 522 approaches the transmission block 5224, driving the first spring 5233 to be compressed, and the elastic force of the first spring 5233 is transmitted to the piezoelectric body 5234 through the transmission piece 5235, so that the piezoelectric body 5234 is externally pressed and outputs a corresponding electric signal. The shorter the strip-shaped material, the greater the axial tensioning force, and thus the greater the relative rotation angle between the traction wheel 521 and the side disc 522, the greater the compression amount of the first spring 5233, and the greater the amplitude of the electric signal generated by the piezoelectric body 5234. The control system can detect, record and determine the real-time tension state of the strip-shaped material according to the strength of the electric signal.

[0052] When the control system detects that the strip tension exceeds the set threshold, the electromagnet 5246 is turned on. The energized electromagnet 5246 generates an attractive force to attract and fix the attractable end of the slide column 5243, so that the slide column 5243 moves to the electromagnet 5246 direction against the elastic force of the second spring 5244. With the displacement of the slide column 5243, the second spring 5244 is compressed, and the slide column 5243 drives the clamping plate 5241 to slide on the inner ring 5222, so that the clamping teeth 5242 on the clamping plate 5241 are withdrawn from the clamping groove. At this time, the side disc 522 is disengaged from the clamping relationship with the connecting column 531 on the roller body 53, and the side disc 522 is in a freely rotatable state relative to the connecting column 531. Since there is friction between the traction wheel 521 and the strip, the traction wheel 521 cannot continue to rotate with the roller body 53, and the traction action is immediately released.

[0053] At the same time, the compression force of the transmission block 5224 on the first spring 5233 disappears, the first spring 5233 automatically rebounds, and pushes the side disc 522 to rotate reversely relative to the connecting column 531, to realize the tension release action, thereby rapidly releasing the abnormally high tension on the strip, avoiding the breakage or plastic deformation of the strip due to overload.

[0054] During the tension release, the traction wheel 521 remains stationary, and the strip corresponding to this position is no longer subjected to the traction force, and its tension is completely eliminated. After the tension release process ends, the control system turns off the electromagnet 5246, so that the attractive force disappears. The electromagnet 5246 is de-energized to release the slide column 5243, the second spring 5244 is reset and pushes the slide column 5243 to return to the initial position. The slide column 5243 returns to the initial position while driving the clamping plate 5241 to slide again, so that the clamping teeth 5242 are re-embedded in the clamping groove, and the side disc 522 is reliably clamped with the connecting column 531 again. Subsequently, the roller body 53 resumes driving the traction wheel 521, the traction wheel 521 re-applies the traction force to the strip, and the device returns to the normal operating state.

[0055] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. A granulating device for plastic fragments with multi-stage screening function, comprising a machine shell (1), a motor (2) is installed on the machine shell (1), characterized in that: The shearing roller (3) is rotatably installed on the casing (1), one end of the shearing roller (3) is in transmission connection with the output shaft of the motor (2) through a belt pulley, a traction roller (5) is rotatably installed on the casing (1), the traction roller (5) is in transmission engagement with the shearing roller (3), a support table (6) is installed in the casing (1), the support table (6) is located below the traction roller (5), a guide roller (4) is rotatably installed in the casing (1); The traction roller (5) comprises a roller body (53), the roller body (53) is rotatably installed on the casing (1), and a plurality of disc-shaped traction devices (52) are installed on the roller body (53).

2. The granulating device for plastic fragments with multi-stage screening function according to claim 1, characterized in that: The disc-shaped traction device (52) comprises a side disc (522), the side disc (522) is rotatably installed with a traction wheel (521), a plurality of tension releasing mechanisms (524) are installed in the side disc (522), a plurality of connecting columns (531) are arranged on the roller body (53), the side disc (522) is rotatably installed on the connecting column (531), the side disc (522) is in engagement with the connecting column (531) through the tension releasing mechanism (524), and a plurality of tension detecting mechanisms (523) are installed between the side disc (522) and the traction wheel (521).

3. The granulating device for plastic pieces with multi-stage screening function according to claim 2, characterized in that: The side disc (522) is provided with an outer ring (5221), the outer ring (5221) is provided with a force transmission block (5224), the side disc (522) is provided with an inner ring (5222), the tension releasing mechanism (524) is installed on the inner ring (5222), the tension detecting mechanism (523) is installed between the force transmission block (5224) and the traction wheel (521), and the inner ring (5222) is rotatably installed on the connecting column (531).

4. The granulating device for plastic pieces with multi-stage screening function according to claim 3, characterized in that: The tension releasing mechanism (524) comprises a sliding column (5243) and an electromagnet (5246), the sliding column (5243) is slidably installed on the inner ring (5222), one end of the sliding column (5243) is provided with an engagement plate (5241), a plurality of engagement teeth (5242) are arranged on the engagement plate (5241), a plurality of engagement grooves are uniformly arranged on the connecting column (531), the engagement teeth (5242) are embedded in the engagement grooves, a second spring (5244) is installed between the engagement plate (5241) and the inner ring (5222), the electromagnet (5246) is installed on the inner wall of the outer ring (5221), the other end of the sliding column (5243) is a adsorbable end, and the electromagnet (5246) corresponds to the position of the adsorbable end of the sliding column (5243).

5. The granulating device for plastic pieces having a multi-stage screening function according to claim 3, characterized in that: The tension detecting mechanism (523) comprises a force transmission frame (5231), the force transmission frame (5231) is installed on the inner wall of the traction wheel (521), an arc-shaped sliding rod (5232) is installed on the force transmission frame (5231), the arc-shaped sliding rod (5232) is in sliding connection with the force transmission block (5224), a piezoelectric body (5234) is installed on the force transmission block (5224), a force transmission sheet (5235) is installed on the piezoelectric body (5234), and a first spring (5233) is installed between the force transmission sheet (5235) and the force transmission frame (5231).

6. The granulating device for plastic pieces having a multi-stage screening function according to claim 4, characterized in that: A plurality of damping grooves (5245) are arranged on the slide column (5243), and a plurality of convex rings (5223) are arranged on the inner ring (5222) in contact with the slide column (5243).

7. The granulating device for plastic pieces with multi-stage screening function according to claim 2, characterized in that: An annular groove (5211) is arranged on the traction wheel (521), and a plurality of anti-skid lines (5212) are arranged in the annular groove (5211).

8. The granulating device for plastic pieces having a multi-stage screening function according to claim 1, characterized in that: A second gear (51) is arranged on one side of the roller body (53), a first gear (31) is arranged on one side of the shearing roller (3), the first gear (31) is in meshing transmission with the second gear (51), and a hopper (11) is arranged on the shell (1).

9. The granulating device for plastic pieces having a multi-stage screening function according to claim 1, characterized in that: A plurality of roller knives (32) are arranged on the shearing roller (3), the roller knives (32) and the edges of the supporting table (6) form a shearing structure, and a plurality of guide grooves are arranged on the guide roller (4).

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