A one-piece doctor blade holder assembly for a shredder and a method of preventing loosening of the assembly

Abstract

The application discloses a whole type scraper holder group for a shredder and a locking-free mounting method thereof, and relates to the technical field of shredder accessories. In view of the problems of low mounting precision, easy loosening of bolts, high maintenance cost and poor pre-tightening force retention of traditional mounting methods of the existing split type holder, the holder group comprises a back plate and integrally cast upper and lower holders, and a blade is detachably fixed to the holder; the back plate is provided with a gasket groove with an inclined surface groove on the back surface, and a double-stacked self-locking locking gasket is arranged in the gasket groove; the back plate, the gasket groove and the locking gasket are integrally mounted on the shell through bolts. The mounting method adopts a three-step torque method to tighten the bolts in stages, and realizes double locking prevention by combining a pre-tightening force calculation formula and a thread locking agent. The application has high mounting precision, excellent locking prevention performance, a pre-tightening force retention rate of more than 84% after 2000 hours of vibration, low maintenance cost, long service life, and is widely applicable to various shredder equipment.

Description

Technical Field

[0001] This invention relates to the technical field of shredder accessories, and more particularly to an integral scraper holder assembly for a shredder and its anti-loosening installation method. Background Technology

[0002] A shredder is a mechanical device used to break large pieces of material into smaller pieces. It is widely used in industries such as waste disposal, plastic recycling, wood processing, and metal crushing. The scraper holder assembly is one of the core components of a shredder, and its structural design directly affects the shredding effect, working efficiency, and service life of the shredder.

[0003] Most existing shredders use a split structure for their scraper holders, meaning that the upper and lower scraper holders are installed independently on the shredder housing. This structure has the following significant drawbacks: First, installation accuracy is difficult to guarantee. Positional deviations can easily occur during the separate installation of the upper and lower blade holders, leading to uneven gaps between the upper and lower blades. This results in poor shredding performance, inconsistent material particle size, and even material jamming and machine stalling. Second, the connection strength of the split blade holder is low. Under the long-term alternating impact and vibration during shredding, the connecting bolts are prone to loosening, and the blade holder is prone to displacement, requiring frequent shutdowns for inspection and adjustment, which seriously affects production continuity. Third, adjusting the blade holder gap is difficult. When the blade wear causes the gap to widen, it is usually necessary to disassemble the entire upper or lower blade holder for adjustment. The maintenance process is cumbersome, time-consuming, and the adjustment accuracy is difficult to control. Fourth, the blade holder and the housing are in rigid contact, which cannot effectively buffer the impact force during shredding, easily leading to blade holder deformation and breakage, shortening the blade holder's service life. Fifth, the blade and blade holder are mostly an integral structure. When the blade wears out, the entire blade holder needs to be replaced, resulting in high operating costs.

[0004] In addition, the existing technology for installing the blade holder mostly adopts the traditional single torque method to tighten the bolts, which has low preload control accuracy and is prone to uneven or insufficient preload, further increasing the risk of bolt loosening; and lacks targeted anti-loosening installation technology, which cannot adapt to the harsh working conditions of strong vibration and high impact of shredder. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing an integral scraper holder assembly for shredders and its anti-loosening installation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An integral scraper holder assembly for a shredder includes a back plate, an upper blade holder, and a lower blade holder. The upper blade holder has multiple sets of upper blades arranged in parallel at equal intervals and has multiple sets of parallel mounting holes A. The lower blade holder has multiple sets of lower blades arranged in parallel at equal intervals and has multiple sets of parallel mounting holes B. The back plate has mounting holes C corresponding to mounting holes A and B. The upper and lower blade holders are mounted side-by-side on the back plate, which is mounted on the shredder housing. The shredder housing has mounting holes D corresponding to mounting holes C. A gasket groove is provided at the mounting hole on the side of the back plate facing the shredder housing, and a gasket is installed in the gasket groove.

[0007] Furthermore, the upper and lower blades are respectively fixed to the upper and lower blade holders by detachable bolts, and the upper and lower blades are arranged side by side.

[0008] Furthermore, both the upper and lower tool posts are integral casting structures, the length of the upper tool post is equal to the length of the lower tool post, and the distance between the upper and lower tool posts is 2-5mm.

[0009] Furthermore, the washer is a double-layered self-locking anti-loosening washer, and the bottom of the washer groove is provided with an inclined groove that matches the surface of the double-layered self-locking anti-loosening washer.

[0010] Furthermore, the back plate has symmetrical screw holes at both ends of its top for mounting bolt lugs during installation.

[0011] Furthermore, the upper tool post, lower tool post, and back plate are all made of alloy steel and have undergone quenching treatment, with a hardness of HRC45-55.

[0012] Furthermore, the upper and lower blade holders are arranged side by side on the back plate, which is located on the shredder housing. The upper blade holder, lower blade holder, and back plate are then integrally mounted on the shredder housing using detachable bolts.

[0013] A method for preventing loosening of an integral scraper holder assembly in a shredder includes the following steps: Step 1: Install the lifting bolts through the screw holes at both ends of the top of the back plate, place the upper and lower blade holders on the front of the back plate, align the mounting holes A and B with the corresponding mounting holes C, and insert the connecting bolts to initially connect the upper and lower blade holders to the back plate to form a whole. Lift the entire back plate to the installation position of the shredder housing using the lifting bolts. Step 2: Slide all the double-layered self-locking anti-loosening washers onto the connecting bolts and place them into the corresponding washer grooves on the back of the back plate, so that the beveled surface of the double-layered self-locking anti-loosening washers fits tightly with the beveled groove at the bottom of the washer groove; align the connecting bolts with the mounting holes D and insert them. Step 3: Tighten the connecting bolts using the step torque method. First stage: Tighten at a speed of 5 rpm to 30% of the preload F; Second stage: Tighten at a speed of 2 rpm to 80% of the preload F; Third stage: Tighten back 15°±2° at a speed of 0.5 rpm to 100% of the preload F.

[0014] Furthermore, the formula for calculating the preload F is as follows: Where: σy is the yield strength of the bolt material (MPa), and As is the stress cross-sectional area of ​​the bolt (mm²). 2 K is the working condition coefficient, and the vibration working condition is taken as 1.8-2.2.

[0015] Furthermore, after step three is completed, a locking agent is applied to the threaded portion of the connecting bolt, and the curing time is ≤10 minutes.

[0016] The beneficial effects of this invention are as follows: 1. Adopting an integrated installation structure, the upper and lower blade holders are pre-installed on the back plate and then installed into the housing as a whole, which avoids the deviation of separate installation from the source, ensures uniform blade gap, stable shredding, no material jamming, and improves the consistency of material crushing particle size by more than 30%.

[0017] 2. The back plate is equipped with a gasket groove with a sloping groove at the bottom, which, together with the double-layered self-locking anti-loosening washer, has a double effect of sawtooth engagement and sloping wedge tightening, and the anti-loosening effect is more than 5 times that of ordinary flat washers. It will not loosen under long-term vibration and the operation is more stable.

[0018] 3. The innovative three-step torque method is adopted for installation, which controls the bolt preload in stages, avoiding uneven preload and bolt stress concentration caused by single tightening, and improving the preload retention rate by more than 60%. With the scientific preload calculation formula, it can be precisely adjusted according to different bolt specifications and working conditions, and has strong adaptability.

[0019] 4. Applying a locking agent to the bolt threads forms a double anti-loosening system, further enhancing connection reliability and reducing downtime for maintenance.

[0020] 5. Symmetrical screw holes are provided on the top of the back plate, which can be quickly installed with bolt lifting lugs, making it convenient for the whole unit to be hoisted into the shell, improving installation efficiency by more than 50%, and the positioning accuracy can reach ±0.1mm.

[0021] 6. The blades are fixed with detachable bolts, and only one blade needs to be replaced when worn, without replacing the entire tool holder, reducing maintenance costs by more than 60%.

[0022] 7. The entire piece is made of alloy steel and has been quenched, resulting in high strength, wear resistance, and impact resistance, extending the tool holder's service life by 2-3 times. Attached Figure Description

[0023] Figure 1This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the disassembled structure of the present invention; Figure 3 This is a side cross-sectional view of the present invention. Figure 4 This is an enlarged view of a partial structure of the backplate of the present invention; Figure 5 This is a schematic diagram of the preload variation using the three-step torque method of the present invention; Figure 6 This is a line graph comparing the preload decay of the traditional single-torque method and the three-step torque method of this invention. In the diagram: 1. Upper blade holder; 11. Mounting hole A; 2. Upper blade; 3. Lower blade holder; 31. Mounting hole B; 4. Lower blade; 5. Back plate; 51. Mounting hole C; 52. Screw hole; 53. Gasket groove; 54. Washer; 6. Shredder housing; 61. Mounting hole D. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0025] Example 1

[0026] like Figure 1-4 As shown in this embodiment, an integrated scraper holder assembly for a shredder is provided, suitable for small shredders processing general-purpose plastics such as PE and PP. It includes a back plate 5, an upper blade holder 1, and a lower blade holder 3. Eight sets of upper blades 2 are arranged side-by-side at equal intervals on the front of the upper blade holder 1. Each set of upper blades 2 has a set of mounting holes A11 on both sides, meaning each set of upper blades 2 is fixed to the upper blade holder 1 by two sets of hexagonal bolts. Eight sets of lower blades 4 are arranged side-by-side at equal intervals on the front of the lower blade holder 3. Each set of lower blades 4 has a set of mounting holes B31 on both sides, meaning each set of lower blades 4 is also fixed to the lower blade holder 3 by two sets of hexagonal bolts. The upper blades 2 and lower blades 4 are arranged in a one-to-one parallel arrangement, ensuring that the material is simultaneously sheared during the shredding process, thus improving shredding efficiency.

[0027] The front of the back plate 5 has mounting holes C51 corresponding to mounting holes A11 and B31. The upper blade holder 1 and the lower blade holder 3 are fixedly mounted side by side on the front of the back plate 5 by connecting bolts passing through mounting holes A11, C51, and D61 on the shredder housing 6. The upper blade holder 1 and the lower blade holder 3 are both 1200mm long, 150mm wide, and 20mm thick. The initial distance between the lower edge of the upper blade holder 1 and the upper edge of the lower blade holder 3 is 3mm.

[0028] The back plate 5 has two sets of M16 screw holes 52 symmetrically arranged at both ends of its top, used for positioning with lifting bolts during installation. The back plate 5 is 30mm thick.

[0029] Around each mounting hole C51 on the side of the back plate 5 facing the shredder housing 6 (i.e., the back side), there is a circular gasket groove 53. The gasket groove 53 is 10mm deep and 24mm in diameter. The bottom of the gasket groove 53 has a beveled groove that matches the surface of the double-layer self-locking anti-loosening washer, and the beveled groove has an inclination angle of 3°. A double-layer self-locking anti-loosening washer 54 is installed in the gasket groove 53. The washer 54 is M12, and the surfaces of its upper and lower pieces are respectively provided with interlocking serrations and bevels that match the beveled grooves. When the connecting bolts are tightened, the serrations of the double-layer self-locking anti-loosening washer 54 interlock to generate a huge interlocking force. At the same time, the wedging effect of the beveled grooves and the bevels of the washers further enhances the anti-loosening effect, which can effectively prevent the bolts from loosening under vibration.

[0030] The upper blade holder 1, lower blade holder 3, and back plate 5 are all made of 40Cr alloy steel and have undergone overall quenching treatment, achieving a surface hardness of HRC50. This results in high tensile strength, yield strength, and impact toughness, enabling them to withstand the enormous impact forces during shredding. The upper blade 2 and lower blade 4 are made of W6Mo5Cr4V2 high-speed steel, with precision-ground and nitrided cutting edges, achieving a hardness of HRC62-65. This provides high sharpness, good wear resistance, and a long service life.

[0031] Anti-loosening installation method The tool holder assembly in this embodiment adopts the following anti-loosening installation method: Step 1: Install M16 lifting bolts through the screw holes 52 at both ends of the top of the back plate 5. Place the upper blade holder 1 and the lower blade holder 3 on the front of the back plate 5. Align the mounting holes A11 and B31 with the corresponding mounting holes C51. Insert the M12 connecting bolts and tighten them by hand until there is no looseness. Initially connect the upper blade holder 1 and the lower blade holder 3 to the back plate 5 to form a whole. Lift the entire back plate 5 to the installation position of the shredder housing 6 using the lifting bolts. Adjust the back plate 5 so that the mounting holes C51 and D61 are completely aligned.

[0032] Step 2: Slide all M12 double-layer self-locking anti-loosening washers 54 onto the tail of the connecting bolts and place them into the corresponding gasket grooves 53 on the back of the back plate 5. Rotate the washers to ensure that the beveled surface of the washers fits tightly against the beveled groove at the bottom of the gasket groove 53, ensuring that the washers are not warped or misaligned.

[0033] Step 3: Tighten the connecting bolts using the step-by-step torque method. First, calculate the preload F: In this embodiment, an 8.8 grade M12 bolt is used, with a bolt material yield strength σy = 640 MPa and a bolt stress cross-sectional area As = 84.3 mm². 2 The vibration coefficient K of the plastic shredder is taken as 2.0. Substituting into the formula, we get F=(0.7×640×84.3) / 2.0=18883.2N≈18.9kN.

[0034] First stage: Use a torque wrench to evenly tighten all connecting bolts to 30% of the preload (approximately 5.7 kN) at a speed of 5 rpm. Second stage: Tighten all connecting bolts evenly to 80% of the preload (approximately 15.1 kN) at a speed of 2 rpm. Third stage: Rotate each connecting bolt 15° at a speed of 0.5 rpm, and then tighten it to 100% of the preload (approximately 18.9 kN).

[0035] Step 4: Apply anaerobic threadlocker to the exposed threads of all connecting bolts, allow to cure naturally for 8 minutes, and the installation is complete.

[0036] Example 2

[0037] This embodiment provides an integral scraper holder assembly for a shredder, suitable for medium-sized shredders that process municipal solid waste.

[0038] The upper tool holder 1 has 12 sets of upper blades 2 arranged side-by-side at equal intervals on its front side. Each set of upper blades 2 has one set of mounting holes A11 on each side, meaning each set of upper blades 2 is fixed to the upper tool holder 1 using two sets of M10 hex bolts. Similarly, the lower tool holder 3 has 12 sets of lower blades 4 arranged side-by-side at equal intervals on its front side. Each set of lower blades 4 has one set of mounting holes B31 on each side, meaning each set of lower blades 4 is also fixed to the lower tool holder 3 using two sets of M10 hex bolts. The upper blades 2 and lower blades 4 are arranged in a one-to-one correspondence.

[0039] The front of the back plate 5 has mounting holes C51 corresponding to mounting holes A11 and B31. The upper blade holder 1 and the lower blade holder 3 are fixedly mounted side by side on the front of the back plate 5 by passing through mounting holes A11, C51 and D61 on the shredder housing 6 in sequence with M16 connecting bolts. The upper blade holder 1 and the lower blade holder 3 are both 1800mm long, 180mm wide and 25mm thick. The initial distance between the lower edge of the upper blade holder 1 and the upper edge of the lower blade holder 3 is 4mm.

[0040] The back plate 5 has two sets of M20 screw holes 52 symmetrically arranged at both ends of its top for installing lifting bolts. The back plate 5 is 35mm thick. Around each mounting hole C51 on the side of the back plate 5 facing the shredder housing 6, there is a circular gasket groove 53, 12mm deep and 30mm in diameter. The bottom of the gasket groove 53 has a beveled groove that matches the surface of the double-layered self-locking anti-loosening washer, with an inclination angle of 3.5°. An M16 double-layered self-locking anti-loosening washer 54 is installed within the gasket groove 53.

[0041] The upper tool holder 1, lower tool holder 3, and back plate 5 are all made of 42CrMo alloy steel and have undergone overall quenching treatment, achieving a surface hardness of HRC52. Their impact resistance is superior to 40Cr alloy steel, making them suitable for applications involving mixed hard debris in municipal solid waste. The upper blade 2 and lower blade 4 are made of Cr12MoV alloy tool steel, with cutting edges precision ground and quenched, achieving a hardness of HRC60-63. They offer good wear resistance and are less prone to chipping.

[0042] The tool holder assembly in this embodiment adopts the following anti-loosening installation method: Step 1: Install M20 hoisting bolts through the screw holes 52 at both ends of the top of the back plate 5. Place the upper blade holder 1 and the lower blade holder 3 on the front of the back plate 5. Align the mounting holes A11 and B31 with the corresponding mounting holes C51. Insert the M16 connecting bolts and tighten them by hand until they are secure. After they are initially integrated, hoist them to the installation position of the shredder housing 6 and adjust the alignment of the mounting holes.

[0043] Step 2: Slide all M16 double-layer self-locking anti-loosening washers 54 onto the tail of the connecting bolt and place them into the corresponding washer grooves 53, so that the bevel of the washer fits tightly with the bevel groove.

[0044] Step 3: Calculate the preload F: In this embodiment, an 8.8 grade M16 bolt is used, σy=640MPa, As=156.7mm. 2 The vibration coefficient K of the municipal solid waste shredder is taken as 2.1. Substituting it into the formula, we get F=(0.7×640×156.7) / 2.1≈33429N≈33.4kN.

[0045] First stage: Tighten all connecting bolts evenly to 10.0kN (30% preload) at a speed of 5rpm. Second stage: Tighten all connecting bolts evenly to 26.7kN (80% preload) at a speed of 2rpm. Third stage: Rotate each connecting bolt 14° at a speed of 0.5 rpm, and then tighten it to 33.4 kN (100% preload).

[0046] Step 4: Apply high-strength anaerobic threadlocker to the exposed threads of all connecting bolts, allow to cure naturally for 7 minutes, and the installation is complete.

[0047] Example 3

[0048] This embodiment provides an integral scraper holder assembly for a shredder, suitable for large shredders that process thin metals such as scrap iron and scrap aluminum.

[0049] The upper tool holder 1 has 16 sets of upper blades 2 arranged side-by-side at equal intervals on its front side. Each set of upper blades 2 has one set of mounting holes A11 on each side, meaning each set of upper blades 2 is fixed to the upper tool holder 1 using two sets of M12 hex bolts. Similarly, the lower tool holder 3 has 16 sets of lower blades 4 arranged side-by-side at equal intervals on its front side. Each set of lower blades 4 has one set of mounting holes B31 on each side, meaning each set of lower blades 4 is also fixed to the lower tool holder 3 using two sets of M12 hex bolts. The upper blades 2 and lower blades 4 are arranged in a one-to-one correspondence.

[0050] The front of the back plate 5 has mounting holes C51 corresponding to mounting holes A11 and B31. The upper blade holder 1 and the lower blade holder 3 are fixedly mounted side by side on the front of the back plate 5 by passing through mounting holes A11, C51 and D61 on the shredder housing 6 in sequence with M20 connecting bolts. The upper blade holder 1 and the lower blade holder 3 are both 2400mm long, 220mm wide and 30mm thick. The initial distance between the lower edge of the upper blade holder 1 and the upper edge of the lower blade holder 3 is 5mm.

[0051] The back plate 5 has two sets of M24 screw holes 52 symmetrically arranged at both ends of its top for installing lifting bolts. The back plate 5 is 40mm thick. Around each mounting hole C51 on the side of the back plate 5 facing the shredder housing 6, there is a circular gasket groove 53, 15mm deep and 36mm in diameter. The bottom of the gasket groove 53 has a beveled groove that matches the surface of the double-layered self-locking anti-loosening washer, with an inclination angle of 4°. An M20 specification double-layered self-locking anti-loosening washer 54 is installed within the gasket groove 53.

[0052] The upper blade holder 1, lower blade holder 3, and back plate 5 are all made of 35CrMo alloy steel and have undergone overall quenching treatment, achieving a surface hardness of HRC48. This results in excellent toughness and fatigue resistance, making them suitable for high-impact applications involving metal shredding. The upper blade 2 and lower blade 4 are made of SKD11 cold work die steel, with precision-ground and cryogenically treated cutting edges, achieving a hardness of HRC58-62. This provides excellent resistance to chipping and wear.

[0053] The tool holder assembly in this embodiment adopts the following anti-loosening installation method: Step 1: Install M24 hoisting bolts through the screw holes 52 at both ends of the top of the back plate 5. Place the upper blade holder 1 and the lower blade holder 3 on the front of the back plate 5. Align the mounting holes A11 and B31 with the corresponding mounting holes C51. Insert the M20 connecting bolts and tighten them by hand until they are secure. After they are initially integrated, hoist them to the installation position of the shredder housing 6 and adjust the alignment of the mounting holes.

[0054] Step 2: Slide all M20 double-layer self-locking anti-loosening washers 54 onto the tail of the connecting bolt and place them into the corresponding washer grooves 53, so that the bevel of the washer fits tightly with the bevel groove.

[0055] Step 3: Calculate the preload F: In this embodiment, a 10.9 grade M20 bolt is used, σy=900MPa, As=244.8mm. 2 The coefficient K for the strong vibration condition of the metal shredder is taken as 2.2. Substituting it into the formula, we get F=(0.7×900×244.8) / 2.2≈70058N≈70.1kN.

[0056] First stage: Tighten all connecting bolts evenly to 21.0kN (30% preload) at a speed of 5rpm. Second stage: Tighten all connecting bolts evenly to 56.1kN (80% preload) at a speed of 2rpm. Third stage: Rotate each connecting bolt 16° at a speed of 0.5 rpm, and then tighten it to 70.1 kN (100% preload).

[0057] Step 4: Apply a high-temperature anaerobic thread-locking agent to the exposed threads of all connecting bolts, allow it to cure naturally for 9 minutes, and the installation is complete.

[0058] Example 4

[0059] This comparative embodiment uses the same integral scraper holder assembly structure as Embodiment 1, including the same size upper blade holder, lower blade holder, back plate, M12 connecting bolts of the same specification, M12 double-layer self-locking anti-loosening washers, and the same gasket groove and bevel groove structure. The only difference is that the installation method adopts the traditional single torque method commonly used in the prior art, so as to eliminate the influence of structural variables and accurately compare the preload retention performance and anti-loosening effect of different installation methods.

[0060] Installation steps Step 1: Same as Step 1 in Example 1, install the lifting bolts through the screw holes on the top of the back plate, pre-install the upper and lower blade holders on the back plate to form a whole, and then lift the whole assembly to the installation position of the shredder housing and align the installation holes.

[0061] Step 2: Same as Step 2 in Example 1, insert all M12 double-stacked self-locking anti-loosening washers into the tail of the connecting bolts and place them into the gasket groove on the back of the back plate, so that the bevel of the washer fits tightly with the bevel groove.

[0062] Step 3: Using the traditional single torque method, all connecting bolts are tightened directly at a constant speed of 3 rpm to the preload force F=18.9kN in one go, without staged tightening or rotation.

[0063] Step 4: Same as Step 4 in Example 1, apply the same type of anaerobic thread-locking agent to the exposed thread of the connecting bolt, allow it to cure naturally for 8 minutes, and the installation is complete.

[0064] Preload attenuation comparison test To verify the long-term anti-loosening effect of the two installation methods, continuous vibration tests were conducted on a vibration test bench simulating the actual working conditions of a shredder. The test conditions and data are as follows: Test conditions: vibration frequency 10Hz (corresponding to the working frequency of the shredder spindle), vibration acceleration 5g (simulating the impact vibration when shredding thin metal), ambient temperature 25℃, continuous vibration for 2000 hours, and the remaining preload of 10 bolts was measured every 100 hours using a bolt preload tester, and the average value was taken as the test result.

[0065] Test data (see attached instruction manual) Figure 6 (Preload decay curve) Based on the above test data and appendix Figure 6 It is known that the preload of connecting bolts installed using the traditional single torque method decreases rapidly and exponentially with the extension of vibration time: after 200 hours, the remaining preload is less than 60%, after 500 hours it drops to less than 40%, and after 2000 hours the remaining preload is only 1.6% of the initial value, basically losing its anti-loosening ability. At this time, the tool holder assembly is prone to displacement, resulting in uneven blade gap, jamming, or even equipment failure.

[0066] The connecting bolts installed using the three-step torque method of this invention exhibit extremely slow preload decay: after 2000 hours of continuous vibration, the remaining preload remains above 84% of the initial value, providing a consistently stable clamping force. The core reason for this is that traditional single-torque tightening methods easily lead to elastic hysteresis and stress concentration in the bolts, and the preload uniformity of each bolt is poor. The three-step torque method of this invention, through staged low-speed tightening combined with a 15°±2° rotation operation, effectively eliminates the elastic deformation and assembly stress of the bolts, resulting in a more uniform preload distribution. Simultaneously, the double-layered self-locking anti-loosening washers and the wedging effect of the inclined groove continuously compensate for minor preload decay. The combination of these two factors achieves a long-term reliable anti-loosening effect.

[0067] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An integral scraper holder assembly for a shredder, comprising a back plate (5), an upper blade holder (1), and a lower blade holder (3), characterized in that: The upper blade holder (1) has multiple sets of upper blades (2) arranged in parallel at equal intervals. The upper blade holder (1) has multiple sets of mounting holes A (11) arranged in parallel. The lower blade holder (3) has multiple sets of lower blades (4) arranged in parallel at equal intervals. The lower blade holder (3) has multiple sets of mounting holes B (31) arranged in parallel. The back plate (5) has mounting holes C (51) corresponding to mounting holes A (11) and B (31). The upper blade holder (1) and lower blade holder (3) are mounted side by side on the back plate (5). The back plate (5) is mounted on the shredder housing (6). The shredder housing (6) has mounting holes D (61) corresponding to mounting holes C (51). A gasket groove (53) is provided at the mounting hole C (51) on the side of the back plate (5) close to the shredder housing (6). A gasket (54) is installed in the gasket groove (53).

2. The integral scraper holder assembly for a shredder according to claim 1, characterized in that: The upper blade (2) and the lower blade (4) are fixed to the upper blade holder (1) and the lower blade holder (3) respectively by detachable bolts, and the upper blade (2) and the lower blade (4) are arranged side by side.

3. The integral scraper holder assembly for a shredder according to claim 1, characterized in that: The upper tool holder (1) and the lower tool holder (3) are both integral casting structures. The length of the upper tool holder (1) is equal to the length of the lower tool holder (3), and the distance between the upper tool holder (1) and the lower tool holder (3) is 2-5mm.

4. The integral scraper holder assembly for a shredder according to claim 1, characterized in that: The washer (54) is a double-layered self-locking anti-loosening washer, and the bottom of the washer groove (53) is provided with a sloping groove that matches the surface of the double-layered self-locking anti-loosening washer.

5. The integral scraper holder assembly for a shredder according to claim 1, characterized in that: The back plate (5) has screw holes (52) symmetrically provided at both ends of its top.

6. The integral scraper holder assembly for a shredder according to claim 1, characterized in that: The upper tool holder (1), lower tool holder (3) and back plate (5) are all made of alloy steel with a hardness of HRC45-55.

7. The integral scraper holder assembly for a shredder according to claim 1, characterized in that: The upper blade holder (1) and the lower blade holder (3) are arranged side by side on the back plate (5), which is located on the shredder housing (6). The upper blade holder (1), the lower blade holder (3) and the back plate (5) are installed together on the shredder housing (6) by detachable bolts.

8. A method for preventing loosening of an integral scraper holder assembly for a shredder according to any one of claims 1-7, characterized in that: Includes the following steps: Step 1: Install the lifting bolts through the screw holes at both ends of the top of the back plate, place the upper and lower blade holders on the front of the back plate, align the mounting holes A and B with the corresponding mounting holes C, and insert the connecting bolts to initially connect the upper and lower blade holders to the back plate to form a whole. Lift the entire back plate to the installation position of the shredder housing using the lifting bolts. Step 2: Slide all the double-layered self-locking anti-loosening washers onto the connecting bolts and place them into the corresponding washer grooves on the back of the back plate, so that the beveled surface of the double-layered self-locking anti-loosening washers fits tightly with the beveled groove at the bottom of the washer groove; align the connecting bolts with the mounting holes D and insert them. Step 3: Tighten the connecting bolts using the step-by-step torque method. First stage: Rotate at 5 rpm to 30% of the preload F; Second stage: Rotate at 2 rpm to 80% of the preload F; Third stage: Rotate at a speed of 0.5 rpm for 15° ± 2°, then tighten to 100% of the preload force F.

9. A method for preventing loosening of an integral scraper holder assembly for a shredder according to claim 8, characterized in that: The formula for calculating the preload F is: in: σy: Yield strength of bolt material (MPa) As: Bolt stress cross-sectional area (mm²) 2 ) K: Working condition coefficient, taken as 1.8-2.2 for vibration working conditions.

10. A method for preventing loosening of an integral scraper holder assembly for a shredder according to claim 8, characterized in that: After step three is completed, apply a locking agent to the threaded part of the connecting bolt, and cure for ≤10 minutes.

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