A multi-stage crushing device for waste plastic recycling

Abstract

The application provides a multi-stage crushing device for waste plastic recycling, which comprises a rack, a primary crushing mechanism and a secondary crushing mechanism. The first cutter roll and the second cutter roll are arranged in parallel in the primary crushing mechanism, a plurality of crushing cutter discs are arranged on the two cutter rolls in the axial direction and staggered, the diameter of the circumscribed circle of the crushing cutter disc gradually decreases towards the two ends along the axis, which can prevent flexible plastic from winding and improve the uniformity of the particle size of the discharged material. The secondary crushing mechanism is located below the primary crushing mechanism and is provided with a movable cutter roll and a fixed cutter disc. An overload protection structure is arranged on the fixed cutter disc. The structure can automatically adjust the distance between the movable cutter roll and the fixed cutter disc according to the crushing pressure, so as to avoid damage to the equipment by hard foreign matters such as metal. The device realizes step-by-step processing of coarse crushing and fine crushing through two-stage crushing, improves the crushing efficiency and the quality of the discharged material, enhances the operation safety and stability, reduces the maintenance cost, and is suitable for the pretreatment process of waste plastic recycling.

Description

Technical Field

[0001] This invention belongs to the field of plastic recycling technology, and specifically relates to a multi-stage crushing device for recycling waste plastics. Background Technology

[0002] Plastics are polymers formed from monomers through addition or condensation polymerization, exhibiting excellent plasticity. With the continuous growth in the consumption of plastic products, the amount of waste plastics generated is also increasing dramatically. Recycling and reusing waste plastics not only reduces white pollution and conserves petroleum resources, but also has significant economic and social benefits. In the recycling process of waste plastics, crushing is an essential pre-processing step, its purpose being to break large pieces of waste plastic products into particles or fragments suitable for subsequent washing, sorting, granulation, and other processes.

[0003] Currently, waste plastic crushing mainly employs mechanical energy crushing methods. This involves using crushing machinery to exert forces such as compression, shearing, grinding, and impact on the material, deforming the plastic until it breaks. Existing waste plastics vary in material composition, and there are many types of crushing equipment. Typically, a single crusher is used, such as a roller crusher or a jaw crusher. Single-stage crushing devices usually only have one set of crushing mechanisms, making it difficult to simultaneously meet the dual requirements of coarse and fine crushing, resulting in unsatisfactory crushing effects and uneven output particle size. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a multi-stage crushing device for waste plastic recycling, which can improve the crushing effect and improve the uniformity of the output particle size.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A multi-stage crushing device for recycling waste plastics according to an embodiment of the present invention includes: frame; A primary crushing mechanism includes a first cutter roller and a second cutter roller arranged in parallel within the primary crushing mechanism. The first cutter roller and the second cutter roller are respectively provided with a plurality of crushing discs along the axial direction. The crushing discs on the first cutter roller and the crushing discs on the second cutter roller are staggered along the axial direction. The diameter of the outer circle of the crushing disc gradually decreases from the axis towards both ends. The secondary crushing mechanism is located below the primary crushing mechanism. The secondary crushing mechanism is equipped with a moving cutter roller and a fixed cutter disc. The fixed cutter disc is equipped with an overload protection structure, which can adjust the distance between the moving cutter roller and the fixed cutter disc according to the pressure.

[0006] According to some embodiments of the present invention, the outer periphery of the moving cutter roller is provided with a plurality of trapezoidal grooves, and a first cutter holder is provided in each trapezoidal groove. A first blade is detachably provided in the first cutter holder, and the cutting edge of the first blade extends axially. The fixed cutter disc includes a second blade and a second cutter holder, the second blade and the second cutter holder are detachably connected, and the cutting edge of the second blade is parallel to the cutting edge of the first blade. The overload protection structure is provided on the second cutter holder.

[0007] According to some embodiments of the present invention, the overload protection structure includes a wedge, a fixed tool mounting base, and an elastic block; the wedge and the second tool holder are fixedly connected, the fixed tool mounting base is provided with a wedge groove corresponding to the wedge, the elastic block is disposed in the wedge groove, one end of the elastic block abuts against the wedge, and the other end of the elastic block abuts against the fixed tool mounting base.

[0008] According to some embodiments of the present invention, the angle between the inclined surface of the wedge and the horizontal surface is β; wherein, 10°≤β≤20°.

[0009] According to some embodiments of the present invention, the second blade and the horizontal plane have an included angle α, wherein 0°≤α≤5°.

[0010] According to some embodiments of the present invention, the crushing discs on the first cutter roller and the second cutter roller are arranged in a spiral shape along the axial direction; the crushing disc includes a hub, a toothed plate and a spacer, a plurality of mounting grooves are provided on the peripheral sidewall of the hub, a plurality of toothed plates are provided, and the plurality of toothed plates are respectively disposed in the mounting grooves. The toothed plates are detachably connected to the hub by locking bolts, and a chip-receiving groove is provided between two adjacent toothed plates in the circumferential direction; the spacer is sleeved on the first cutter roller and the second cutter roller, and each spacer is located between two axially adjacent crushing discs for fixing the axial spacing of the crushing discs.

[0011] According to some embodiments of the present invention, the primary crushing mechanism is provided with a first housing, and the inner sidewall of the first housing is provided with ribs that are adapted to the outer circular contour of the crushing cutter disc, and the ribs are provided at equal intervals with the crushing cutter disc.

[0012] According to some embodiments of the present invention, the secondary crushing mechanism is provided with a second housing, a second feed inlet is provided at the upper end of the second housing, and a second discharge outlet is provided at the lower end of the second housing; a hopper is inclinedly provided at the second feed inlet, and a plurality of screen rollers are provided at the second feed inlet.

[0013] According to some embodiments of the present invention, the device further includes a drive motor, a reducer, a first pulley, a second pulley, a first synchronous belt, a first gear, a second gear, and a brake; the drive motor is mounted on the frame, the output end of the drive motor is connected to the first pulley, the input end of the reducer is connected to the second pulley, and the first pulley and the second pulley are connected by a first synchronous belt; the output end of the reducer is connected to one end of the first cutter roller by the brake, the first gear is fixedly connected to the other end of the first cutter roller, the first gear meshes with the second gear, and the second gear is fixedly connected to the second cutter roller.

[0014] According to some embodiments of the present invention, the device further includes a third pulley, a fourth pulley, and a second synchronous belt. The third pulley is drivenly connected to the first cutter roller, the fourth pulley is drivenly connected to the moving cutter roller, and the third pulley and the fourth pulley are drivenly connected via the second synchronous belt.

[0015] A multi-stage crushing device for recycling waste plastics according to an embodiment of the present invention has at least the following beneficial effects: According to the present invention, the scheme achieves step-by-step processing of coarse and fine crushing through a two-stage crushing mechanism consisting of primary and secondary crushing. The primary crushing mechanism, with its special gradually changing cutter head outer diameter design, solves the problem of flexible plastic entanglement, improves operational stability, and enhances the uniformity of the output particle size. The secondary crushing mechanism, through its overload protection structure, prevents damage to the equipment from metallic foreign objects, ensuring the continuity and safety of the crushing process. These structures work together to reduce maintenance costs, improve the overall efficiency of the waste plastic crushing process, and provide more stable raw materials for subsequent sorting and granulation stages. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0017] Figure 1 This is a schematic diagram of one structure of the present invention; Figure 2 This is a schematic diagram of a secondary crushing mechanism of the present invention; Figure 3 This is a cross-sectional structural schematic diagram of the secondary crushing mechanism of the present invention; Figure 4 For the present invention Figure 3 A magnified schematic diagram of the local structure at point A; Figure 5 This is a schematic diagram of one structure of the moving blade roller of the present invention; Figure 6 This is a schematic diagram of one possible overload protection structure of the present invention; Figure 7 This is a schematic diagram of a primary crushing mechanism of the present invention; Figure 8 This is a schematic diagram of the structure of the first and second cutter rollers of the primary crushing mechanism of the present invention; Figure 9 This is a cross-sectional structural schematic diagram of the primary crushing mechanism of the present invention.

[0018] The reference numerals in the accompanying drawings include: 100-Frame, 110-Drive motor, 120-Reducer, 130-First pulley, 140-Second pulley, 150-First timing belt, 160-First gear, 170-Second gear, 180-Brake, 191-Third pulley, 192-Fourth pulley, 193-Second timing belt; 200 - Primary crushing mechanism, 210 - First cutter roller, 220 - Second cutter roller, 230 - Crushing disc, 231 - Hub, 2311 - Mounting slot, 232 - Tooth plate, 233 - Spacer, 234 - Locking bolt, 235 - Chip collection groove, 240 - First housing, 241 - Rib; 300 - Secondary crushing mechanism; 310 - Moving cutter roller; 311 - Trapezoidal groove; 312 - First cutter holder; 313 - First blade; 320 - Fixed cutter disc; 321 - Second blade; 322 - Second cutter holder; 330 - Overload protection structure; 331 - Wedge block; 332 - Fixed cutter mounting base; 3321 - Wedge groove; 333 - Elastic block; 340 - Second housing; 341 - Second feed inlet; 342 - Second discharge outlet; 343 - Hopper; 344 - Screen roller. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "top surface," "bottom surface," "inner," "outer," "inner side," and "outer side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0021] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. Where the terms "first," "second," and "third" are used for descriptive purposes and to distinguish technical features, they should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the sequential relationship of the indicated technical features.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The embodiments of this invention will now be described according to its overall structure.

[0023] Reference Figures 1 to 9As shown, this invention discloses a multi-stage crushing device for recycling waste plastics, including a frame 100, a primary crushing mechanism 200, and a secondary crushing mechanism 300. The primary crushing mechanism 200 has a first cutter roller 210 and a second cutter roller 220 arranged parallel to each other. Multiple crushing discs 230 are respectively arranged axially on the first and second cutter rollers 210 and 220, and are staggered axially. The diameter of the circumscribed circle of each crushing disc 230 gradually decreases towards both ends along the axis. The secondary crushing mechanism 300 is located below the primary crushing mechanism 200. The secondary crushing mechanism 300 includes a moving cutter roller 310 and a fixed cutter disc 320. The fixed cutter disc 320 is equipped with an overload protection structure 330, which can adjust the distance between the moving cutter roller 310 and the fixed cutter disc 320 according to the pressure. Specifically, in this embodiment, the primary crushing mechanism 200 is a double-roll crusher, which can provide a large shearing impact force to crush large pieces of plastic. The secondary crushing mechanism 300 is a plate crusher, which can further crush the plastic after primary crushing into specified particles, while removing some plastic with strong plasticity and elasticity. Specifically, the primary crushing mechanism 200 has a first cutter roller 210 and a second cutter roller 220 arranged in parallel inside. The first cutter roller 210 and the second cutter roller 220 are respectively equipped with multiple crushing discs 230 along the axial direction. The crushing discs 230 on the first cutter roller 210 and the crushing discs 230 on the second cutter roller 220 are staggered along the axial direction. The outer diameter of the circumscribed circle of each crushing disc 230 gradually decreases from the axis of the cutter roller to both ends. This structure makes the outer diameter of the disc in the middle of the cutter roller larger than the outer diameter of the discs at both ends. When the waste plastic contains flexible plastic, the flexible plastic will move towards the middle region of the cutter roller under the shearing action of the staggered discs. Because the outer diameter of the central cutter head is larger, the plastic is less likely to slide to either end. Therefore, the flexible plastic is confined to the central area of ​​the cutter rollers, reducing the possibility of it entangled with the first cutter roller 210, the second cutter roller 220, and the bearings. This design effectively prevents equipment jamming caused by the flexible plastic entanglement. Simultaneously, the material is concentrated in the central area of ​​the cutter rollers for crushing, which is beneficial for obtaining crushed products with more uniform particle size. The secondary crushing mechanism 300 is equipped with a moving cutter roller 310 and a fixed cutter head 320. The moving cutter roller 310 and the fixed cutter head 320 cooperate to further crush the material. The fixed cutter head 320 is equipped with an overload protection structure 330. The overload protection structure 330 can adjust the distance between the moving cutter roller 310 and the fixed cutter head 320 according to the applied pressure. When hard foreign objects such as metal are mixed into the plastic, the crushing pressure increases. After sensing the pressure change, the overload protection structure 330 automatically increases the distance between the moving cutter roller 310 and the fixed cutter head 320, allowing the hard foreign objects to pass through and preventing damage to the cutter rollers or the fixed cutter head 320. This protection mechanism reduces the risk of equipment damage and minimizes downtime for maintenance due to overload.This design achieves step-by-step crushing of coarse and fine materials through a two-stage crushing mechanism: primary and secondary crushing. The primary crushing mechanism 200, with its specially designed gradually changing cutter head diameter, solves the problem of flexible plastic entanglement, improves operational stability, and enhances the uniformity of the output particle size. The secondary crushing mechanism 300, with its overload protection structure 330, prevents damage to the equipment from metallic foreign objects, ensuring the continuity and safety of the crushing process. These structures work together to reduce maintenance costs, improve the overall efficiency of the waste plastic crushing process, and provide more stable raw materials for subsequent sorting and granulation stages.

[0024] Reference Figures 4 to 6 As shown, the outer periphery of the moving cutter roller 310 is provided with several trapezoidal grooves 311, and each trapezoidal groove 311 is provided with a first cutter holder 312. A first blade 313 is detachably disposed within the first cutter holder 312, and the cutting edge of the first blade 313 extends axially. The fixed cutter disc 320 includes a second blade 321 and a second cutter holder 322, which are detachably connected. The cutting edge of the second blade 321 is parallel to the cutting edge of the first blade 313. An overload protection structure 330 is disposed on the second cutter holder 322. Specifically, in this embodiment, each trapezoidal groove 311 is provided with a first cutter holder 312. The first blade 313 is detachably disposed within the first cutter holder 312. The cutting edge of the first blade 313 extends axially. This structure allows the first blade 313 to generate a shearing action axially when the moving cutter roller 310 rotates. The trapezoidal grooves 311 can fix the first cutter holder 312, preventing it from shifting under force. The first blade 313 is detachable for easy replacement after wear, reducing maintenance costs. An overload protection structure 330 is located on the second blade holder 322. When the material contains hard foreign objects such as metal, the crushing pressure increases. The overload protection structure 330 adjusts the position of the second blade holder 322 according to the pressure change, thereby changing the distance between the moving blade roller 310 and the fixed blade disc 320. The overload protection structure 330, located on the fixed blade holder, can directly control the gap between the fixed and moving blades, resulting in a faster response and protecting the blades and blade roller from damage.

[0025] Reference Figure 4As shown, the overload protection structure 330 includes a wedge 331, a fixed blade mounting base 332, and an elastic block 333. The wedge 331 is fixedly connected to the second blade holder 322. The fixed blade mounting base 332 is provided with a wedge groove 3321 corresponding to the wedge 331. The elastic block 333 is disposed in the wedge groove 3321, with one end of the elastic block 333 abutting against the wedge 331 and the other end abutting against the fixed blade mounting base 332. Under normal operating conditions, the elastic block 333 maintains the initial position of the wedge 331 in the wedge groove 3321, keeping the second blade 321 and the first blade 313 at a preset crushing gap. When a hard foreign object enters the crushing area, the pressure between the moving blade roller 310 and the second blade 321 increases. This pressure is transmitted to the wedge 331 through the second blade holder 322. After being squeezed, the wedge 331 slides along the direction of the wedge groove 3321. During the sliding process, the wedge 331 compresses the elastic block 333. The sliding wedge 331 drives the second cutter holder 322 to move, causing the second blade 321 to move away from the moving cutter roller 310. The gap between the moving cutter roller 310 and the fixed cutter disc 320 increases accordingly. Hard foreign objects then pass through this increased gap. After the foreign object passes, the pressure is released. The elastic block 333 springs back to its original position. The elastic block 333 pushes the wedge 331 and the second cutter holder 322 back to their initial positions. The gap between the moving cutter roller 310 and the fixed cutter disc 320 returns to its preset value. Through this structural design, the wedge 331 cooperates with the wedge groove 3321 to convert the force direction into directional sliding displacement, ensuring reliable operation. The elastic block 333 provides a resettable buffer force, enabling automatic gap adjustment without external power. This design responds quickly and effectively prevents hard foreign objects from causing blade breakage or cutter roller jamming. This structure protects equipment safety and reduces manual intervention and downtime. In this design, the elastic block 333 can be composed of multiple disc springs spliced ​​together, or it can be made of synthetic rubber with low hardness and elasticity, such as polyurethane elastic block 333.

[0026] In some embodiments of the present invention, the angle between the inclined surface of the wedge block 331 and the horizontal plane is β; wherein, 10°≤β≤20°. Specifically, in this embodiment, when β is less than 10°, the wedge block 331 is prone to self-locking and difficult to compress the elastic block 333. If β is greater than 20°, the wedge block 331 is too sensitive to slide after being subjected to force, which may affect the reset accuracy. The range of 10° to 20° ensures that the wedge block 331 can slide reliably when a hard foreign object enters, and is fully reset by being pushed by the elastic block 333 after the pressure is released.

[0027] Reference Figure 4As shown, the second blade 321 forms an angle α with the horizontal plane, where 0°≤α≤5°. The cutting edge of the second blade 321 is slightly raised. This design allows the cutting edge of the second blade 321 to generate an upward shearing force on the material during the crushing process, which is beneficial for the material to be effectively cut. At the same time, when the upper end of the second blade 321 is subjected to pressure greater than a threshold from the direction of the moving cutter roller 310, due to the presence of angle α, this pressure will generate a horizontal component force on the second blade 321 away from the direction of the moving cutter roller 310. This horizontal component force assists in pushing the second cutter holder 322 and the wedge block 331 to move backward along the wedge groove 3321, promoting the blade retraction. This retraction action, in conjunction with the compression of the elastic block 333, increases the distance between the moving cutter roller 310 and the fixed cutter disc 320.

[0028] Reference Figures 7 to 9As shown, the crushing discs 230 on the first cutter roller 210 and the second cutter roller 220 are arranged in a spiral shape along the axial direction. Each crushing disc 230 includes a hub 231, toothed plates 232, and spacers 233. Multiple mounting grooves 2311 are provided on the peripheral sidewall of the hub 231. Multiple toothed plates 232 are provided, each positioned within a mounting groove 2311. The toothed plates 232 are detachably connected to the hub 231 by locking bolts 234. A chip-receiving groove 235 is provided between two adjacent toothed plates 232 in the circumferential direction. Spacers 233 are fitted onto the first cutter roller 210 and the second cutter roller 220, with each spacer 233 located between two axially adjacent crushing discs 230, used to fix the axial spacing of the crushing discs 230. Specifically, in this embodiment, the crushing discs 230 on the first cutter roller 210 and the second cutter roller 220 are arranged in a spiral shape along the axial direction. The helical arrangement of the cutter head allows the cutting teeth to sequentially cut into the material during rotation, creating a continuous shearing effect. Compared to a parallel arrangement, the helical arrangement reduces the impact load when the cutter heads cut simultaneously, minimizes instantaneous torque fluctuations, and results in smoother operation. The crushing cutter head 230 consists of a hub 231, toothed plates 232, and spacers 233. Multiple mounting slots 2311 are provided on the circumferential sidewall of the hub 231. Multiple toothed plates 232 are respectively positioned within the mounting slots 2311. The toothed plates 232 are detachably connected to the hub 231 via locking bolts 234. This structure facilitates individual replacement of the toothed plates 232 after wear, eliminating the need to replace the entire cutter head and reducing maintenance costs. A chip-collecting groove 235 is provided between two circumferentially adjacent toothed plates 232. The chip-collecting groove 235 is used to collect debris and powder generated during the crushing process, preventing debris accumulation in the cutting edge area, reducing frictional heat generation, and improving shearing efficiency. Spacer sleeves 233 are fitted onto the first cutter roller 210 and the second cutter roller 220. Each spacer sleeve 233 is located between two axially adjacent crushing cutter discs 230. The spacer sleeves 233 are used to fix the axial spacing of the crushing cutter discs 230. This spacing determines the accuracy of the staggered arrangement of the cutter discs, ensuring that there is no axial movement between adjacent cutter discs and guaranteeing shearing stability. The spacer sleeves 233 also serve an axial positioning function, reducing installation errors. Through the design of this structure, the helical arrangement reduces impact and improves operational stability. The removable toothed plate 232 facilitates replacement and extends the service life of the cutter rollers. The chip groove 235 improves chip removal and prevents clogging. The spacer sleeves 233 precisely fix the spacing, ensuring consistent crushing performance. These designs collectively improve the shearing efficiency and equipment reliability of the primary crushing mechanism 200.

[0029] In some embodiments of the present invention, the primary crushing mechanism 200 is provided with a first housing 240, and ribs 241 adapted to the outer circular contour of the crushing disc 230 are provided on the inner sidewall of the first housing 240. The ribs 241 are evenly spaced from the crushing disc 230. The crushing disc 230 rotates and shears the material. The ribs 241 are located on the outer edge of the disc. The evenly spaced gaps allow qualified particles after crushing to pass through, but prevent larger pieces or flexible materials from sliding directly off the outside of the disc. The material is thus confined within the staggered working area of ​​the disc and subjected to repeated shearing. At the same time, the ribs 241 also improve the structural strength of the first housing 240.

[0030] In some embodiments of the present invention, the secondary crushing mechanism 300 is provided with a second housing 340, a second feed inlet 341 at the upper end of the second housing 340, and a second discharge outlet 342 at the lower end of the second housing 340; a hopper 343 is inclinedly arranged at the second feed inlet 341, and a plurality of screen rollers 344 are arranged at the second feed inlet 341. Specifically, in this embodiment, the material crushed by the primary crushing mechanism 200 enters the secondary crushing mechanism 300 through the second feed inlet 341, is crushed by the moving cutter roller 310 and the fixed cutter disc 320, and is discharged through the second discharge outlet 342. The hopper 343 is inclinedly arranged at the second feed inlet 341. The hopper 343 is used to receive the material falling from the primary crushing mechanism 200. The inclined arrangement allows the material to slide along the inner wall of the hopper 343 towards the second feed inlet 341 under the action of gravity, avoiding the accumulation or retention of material at the feed inlet and ensuring smooth feeding. Several screen rollers 344 are provided at the second feed inlet 341. The screen rollers 344 are located in the transition area between the hopper 343 and the second feed inlet 341. When the material enters the second feed inlet 341, it first passes through the screen rollers 344 for screening and diversion. The screen rollers 344 can separate large particles from small particles. Small particles pass directly into the crushing area through the gaps between the screen rollers 344, while large particles are blocked and guided to the shearing area of ​​the moving cutter roller 310 and the fixed cutter disc 320 for crushing. The screen rollers 344 also play a role in uniformly distributing the material, making the material evenly distributed in the width direction of the second feed inlet 341, and avoiding local accumulation that would cause uneven load on the moving cutter roller 310. Furthermore, in this embodiment, the screen rollers 344 can rotate in conjunction with an independent transmission mechanism, and some irregular protrusions can also be provided on the screen rollers 344 to improve the material distribution effect of the screen rollers 344.

[0031] In some embodiments of the present invention, the device further includes a drive motor 110, a reducer 120, a first pulley 130, a second pulley 140, a first synchronous belt 150, a first gear 160, a second gear 170, and a brake 180. The drive motor 110 is mounted on the frame 100. The output end of the drive motor 110 is connected to the first pulley 130. The input end of the reducer 120 is connected to the second pulley 140. The first pulley 130 and the second pulley 140 are connected by a transmission via the first synchronous belt 150. The output end of the reducer 120 is connected to one end of the first cutter roller 210 by a transmission via the brake 180. The first gear 160 is fixedly connected to the other end of the first cutter roller 210. The first gear 160 meshes with the second gear 170. The second gear 170 and the second cutter roller 220 are fixedly connected. Furthermore, it also includes a third pulley 191, a fourth pulley 192, and a second synchronous belt 193. The third pulley 191 is drivenly connected to the first cutter roller 210, and the fourth pulley 192 is drivenly connected to the moving cutter roller 310. The third pulley 191 and the fourth pulley 192 are drivenly connected via the second synchronous belt 193. Specifically, the drive motor 110 is mounted on the frame 100. The output end of the drive motor 110 is connected to the first pulley 130. The input end of the reducer 120 is connected to the second pulley 140. The first pulley 130 and the second pulley 140 are drivenly connected via the first synchronous belt 150. When the drive motor 110 is running, power is transmitted to the reducer 120 via the first pulley 130, the first synchronous belt 150, and the second pulley 140. The reducer 120 reduces the rotational speed and increases the output torque. The output end of the reducer 120 is drivenly connected to one end of the first cutter roller 210 via a brake 180. Brake 180 is used to cut off or brake power transmission in a stop or emergency situation. When brake 180 is engaged, power is transmitted from reducer 120 to the first cutter roller 210. First gear 160 is fixedly connected to the other end of first cutter roller 210. First gear 160 meshes with second gear 170. Second gear 170 is fixedly connected to second cutter roller 220. After power is transmitted through first gear 160 and second gear 170, first cutter roller 210 and second cutter roller 220 achieve synchronous counter-rotation. The crushing discs 230 on the two cutter rollers thus form a relative shearing motion. Third pulley 191 is driven to first cutter roller 210. Fourth pulley 192 is driven to moving cutter roller 310. Third pulley 191 and fourth pulley 192 are driven to each other through second synchronous belt 193. When first cutter roller 210 rotates, power is transmitted to moving cutter roller 310 through third pulley 191, second synchronous belt 193 and fourth pulley 192. The moving cutter roller 310 thus obtains rotational power to perform secondary crushing. Through the design of this structure, the first pulley 130 and the first synchronous belt 150 achieve primary speed reduction from the motor to the reducer 120, resulting in smooth transmission. The reducer 120 further reduces the speed and increases the torque to meet the crushing load requirements. The brake 180 can quickly stop the cutter roller in an emergency, improving operational safety.The meshing of the first gear 160 and the second gear 170 enables synchronous and precise transmission of the two cutter rollers, ensuring a constant shearing phase of the staggered cutter discs. The third pulley 191, the fourth pulley 192, and the second synchronous belt 193 transmit power from the primary crushing mechanism 200 to the secondary crushing mechanism 300, eliminating the need for an additional motor and simplifying the overall structure. This transmission layout allows both stages of the crushing mechanism to share the same power source, saving space and cost while ensuring consistent overall machine operation.

[0032] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is obvious that many changes and variations can be made based on the above teachings. Although embodiments of the invention have been shown and described, these specific embodiments are merely explanations of the invention and are not intended to limit it. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. The purpose of selecting and describing exemplary embodiments is to explain the specific principles of the invention and its practical application, so that those skilled in the art, after reading this specification, can make modifications, substitutions, variations, and various choices and changes to the embodiments as needed without departing from the principles and spirit of the invention, provided that such modifications, substitutions, variations, and choices and changes are within the scope of the claims of the invention and are protected by patent law.

Claims

1. A multi-stage crushing device for recycling waste plastics, characterized in that, include: Rack (100); A primary crushing mechanism (200) includes a first cutter roller (210) and a second cutter roller (220) arranged in parallel within the primary crushing mechanism (200). The first cutter roller (210) and the second cutter roller (220) are respectively provided with a plurality of crushing discs (230) along the axial direction. The crushing discs (230) on the first cutter roller (210) and the crushing discs (230) on the second cutter roller (220) are staggered along the axial direction. The diameter of the outer circle of the crushing disc (230) gradually decreases from the center to both ends. A secondary crushing mechanism (300) is disposed below the primary crushing mechanism (200). The secondary crushing mechanism (300) is provided with a moving cutter roller (310) and a fixed cutter disc (320). An overload protection structure (330) is provided on the fixed cutter disc (320). The overload protection structure (330) can adjust the distance between the moving cutter roller (310) and the fixed cutter disc (320) according to the pressure.

2. The multi-stage crushing device for waste plastic recycling according to claim 1, characterized in that, The outer periphery of the moving cutter roller (310) is provided with a plurality of trapezoidal grooves (311), and each trapezoidal groove (311) is provided with a first cutter holder (312). The first cutter holder (312) is detachably provided with a first blade (313), and the cutting edge of the first blade (313) extends axially. The fixed cutter disc (320) includes a second blade (321) and a second cutter holder (322). The second blade (321) and the second cutter holder (322) are detachably connected. The cutting edge of the second blade (321) is parallel to the cutting edge of the first blade (313). The overload protection structure (330) is provided on the second cutter holder (322).

3. The multi-stage crushing device for waste plastic recycling according to claim 2, characterized in that, The overload protection structure (330) includes a wedge (331), a fixed tool mounting base (332), and an elastic block (333); the wedge (331) and the second tool holder (322) are fixedly connected, the fixed tool mounting base (332) is provided with a wedge groove (3321) corresponding to the wedge (331), the elastic block (333) is disposed in the wedge groove (3321), one end of the elastic block (333) abuts against the wedge (331), and the other end of the elastic block (333) abuts against the fixed tool mounting base (332).

4. The multi-stage crushing device for waste plastic recycling according to claim 3, characterized in that, The angle between the inclined surface and the horizontal surface of the wedge (331) is β; where 10°≤β≤20°.

5. The multi-stage crushing device for waste plastic recycling according to claim 4, characterized in that, The second blade (321) has an angle α with the horizontal plane, where 0°≤α≤5°.

6. The multi-stage crushing device for waste plastic recycling according to claim 1, characterized in that, The crushing discs (230) on the first cutter roller (210) and the second cutter roller (220) are arranged in a spiral shape along the axial direction; the crushing disc (230) includes a hub (231), toothed plates (232), and spacers (233). Multiple mounting grooves (2311) are provided on the peripheral sidewall of the hub (231), and multiple toothed plates (232) are provided, each toothed plate (232) being respectively disposed in one of the mounting grooves (2311). The toothed plate (232) is detachably connected to the hub (231) by locking bolts (234), and a chip groove (235) is provided between two adjacent toothed plates (232) in the circumferential direction; the spacer (233) is sleeved on the first cutter roller (210) and the second cutter roller (220), and each spacer (233) is located between two axially adjacent crushing cutter discs (230) to fix the axial spacing of the crushing cutter discs (230).

7. The multi-stage crushing device for waste plastic recycling according to claim 6, characterized in that, The primary crushing mechanism (200) is provided with a first housing (240), and the inner sidewall of the first housing (240) is provided with ribs (241) that are adapted to the outer circular contour of the crushing disc (230), and the ribs (241) and the crushing disc (230) are provided at equal intervals.

8. The multi-stage crushing device for waste plastic recycling according to claim 1, characterized in that, The secondary crushing mechanism (300) is provided with a second housing (340), the upper end of the second housing (340) is provided with a second feed inlet (341), and the lower end of the second housing (340) is provided with a second discharge outlet (342); the second feed inlet (341) is provided with a hopper (343) at an incline, and a number of screen rollers (344) are provided at the second feed inlet (341).

9. The multi-stage crushing device for waste plastic recycling according to claim 1, characterized in that, It also includes a drive motor (110), a reducer (120), a first pulley (130), a second pulley (140), a first synchronous belt (150), a first gear (160), a second gear (170), and a brake (180); the drive motor (110) is mounted on the frame (100), the output end of the drive motor (110) is connected to the first pulley (130), the input end of the reducer (120) is connected to the second pulley (140), the first pulley (130) and the second pulley (140) are connected by transmission through the first synchronous belt (150); the output end of the reducer (120) and one end of the first cutter roller (210) are connected by transmission through the brake (180), the first gear (160) and the other end of the first cutter roller (210) are fixedly connected, the first gear (160) meshes with the second gear (170), and the second gear (170) and the second cutter roller (220) are fixedly connected.

10. The multi-stage crushing device for waste plastic recycling according to claim 9, characterized in that, It also includes a third pulley (191), a fourth pulley (192), and a second synchronous belt (193). The third pulley (191) is connected to the first cutter roller (210) and the fourth pulley (192) is connected to the moving cutter roller (310). The third pulley (191) and the fourth pulley (192) are connected to each other via the second synchronous belt (193).

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