Large steel casting sand mold stable overturning method based on synchronous control of large hook and small hook

Abstract

The invention discloses a large steel casting sand mold stable overturning method based on synchronous control of large and small hooks, and relates to the technical field of steel casting sand mold production. S2, hoisting in the air; s3, the rope is loosened for unloading; s4, turning over in the air; and S5, synchronous falling is carried out. The sand mold is overturned in the air and does not make contact with the ground in the whole process, and the problem that the angle is out of control due to ground contact in a traditional overturning mode is solved. And no strong vibration exists in the overturning process, so that the sinking of the wet sand mold and the falling and scrapping of the dry sand mold are effectively prevented, and the sand mold yield is greatly improved. The sand mold overturning stability is guaranteed, the sand box reinforcing amount is reduced, meanwhile, sand mold overturning cracking is avoided, the sand mold size precision is guaranteed, and the steel casting product quality is improved.

Description

Technical Field

[0001] This invention relates to the field of sand mold production technology for cast steel parts, and in particular to a method for the smooth turning of sand molds for large cast steel parts based on synchronous control of large and small hooks. Background Technology

[0002] The sand mold production process for large steel castings mainly includes the following core steps: First, a wooden or metal mold is designed and fabricated based on the casting drawings, and high-performance molding sand and core sand are prepared. Next, molding and core making are carried out, and the sand mold and core are assembled into a complete casting mold through mold assembly. In the melting stage, molten steel is melted according to the chemical composition, and the molten metal is poured into the mold cavity through the gating system. After the metal cools and solidifies, sand removal and cleaning are performed. Finally, quality inspection ensures the casting is qualified. This process, with its advantages of low cost, strong adaptability, and ability to produce complex large parts, is widely used in the production of steel castings. However, strict control of molding sand properties, pouring parameters, and cleaning processes is necessary to avoid defects such as sand inclusions and sand expansion, ensuring the quality of the castings.

[0003] However, in the existing production process of large cast steel parts using sand molds, the sand molds need to be flipped to complete processes such as demolding, trimming, painting, and box assembly. Currently, the industry commonly uses single-sided straight-lifting or strapped-on flipping. During the flipping process, the sand mold is prone to contact with the ground, and the overhead crane cannot accurately control the flipping angle, leading to flipping failure. Moreover, the strong vibration generated during flipping can easily cause wet sand molds to sink or dry sand molds to fall into the box and be scrapped, seriously affecting product quality and production efficiency. Single-sided straight-lifting or strapped-on flipping can easily cause the sand mold to make hard contact with the ground, leading to flipping failure; the insufficient precision of the overhead crane control makes it difficult to achieve precise angle control, causing deviations in processes such as demolding and trimming.

[0004] There are already relevant patents concerning the tilting and hoisting of sand molds, as detailed below:

[0005] Chinese Patent Application No. CN202421688722.6, entitled "A Tiltable Lifting Device for Small Sand Cores and Molds," belongs to the field of sand core and mold lifting devices. It includes a lifting head, clamping arms, and tilting plates. A suspension ring is connected to the upper end of the lifting head. The clamping arms are mirror-shaped in the same plane, with one end coaxially hinged to the lifting head and the other end connected to a rotating shaft box. Two tilting plates are parallel and oppositely connected to a rotating shaft. When the clamping arms rotate, the two tilting plates can form a clamping engagement. This device can mechanically assist in the transport of small sand cores and molds and achieve synchronous tilting of the sand cores or molds during transport. It has a simple structure, reliable performance, and is easy to use. Applied to casting production, it can reduce the labor intensity of workers, improve product production efficiency, and reduce potential damage or even scrapping of small sand cores and molds during handling and tilting. It also reduces raw material waste, improves the quality of sand cores, molds, and their assembly, and ensures the quality of cast products.

[0006] While the aforementioned existing patents can mechanically assist in the transport of small sand cores and molds during production, and simultaneously rotate them during transport, this approach is only effective for small sand cores and molds. When producing large cast steel molds, the increased volume, weight, and structural complexity of the clamping arm and rotating shaft can lead to problems such as insufficient clamping force causing unstable transport, excessive rotation torque causing mold cracking, insufficient structural rigidity causing device deformation, and insufficient control precision causing positional deviations. This not only fails to effectively reduce worker workload but may also reduce production efficiency and product quality due to increased operational difficulty and the increased risk of mold damage, while simultaneously increasing raw material waste and production costs. Summary of the Invention

[0007] The purpose of this application is to provide a method for the smooth flipping of sand molds for large cast steel parts based on synchronous control of large and small hooks, in order to solve the defects of existing sand mold flipping processes for large cast steel parts.

[0008] This invention utilizes a steel wire rope on a crane's large hook to taut and fix one end of the sand mold, while simultaneously lifting the other end of the sand mold with a small hook. The large and small hooks are controlled to lift the sand mold synchronously, ensuring the entire sand mold is higher than the width of the sand box, guaranteeing that the sand mold does not contact the ground during the flipping process. The sand mold at the small hook end is lowered until the steel wire rope at the small hook end is completely released, and then the steel wire rope is removed. The sand mold suspended on the large hook is rotated 180° so that the side of the sand mold to be flipped faces the small hook end, and then the sand mold is lifted again using the steel wire rope at the small hook end. The large and small hooks are controlled to fall synchronously, allowing the sand mold to smoothly complete the flipping. The device used to implement the above method is a crane lifting system equipped with a large hook and a small hook. The large hook is used to support the overall weight of the sand mold and create an airborne state, while the small hook is used to assist in controlling the flipping angle and the airborne posture of the sand mold.

[0009] The method for smoothly flipping sand molds of large cast steel parts based on synchronous control of large and small hooks specifically includes the following steps:

[0010] S1, hoisting and fixing: use the steel wire rope set on the large hook body to tighten and fix one end of the sand mold, and at the same time use the steel wire rope set on the small hook body to lift the other end of the sand mold to form two-point support.

[0011] S2, Aerial Lifting: Control the large hook body and the small hook body to lift the sand mold synchronously, so that the overall height of the sand mold is higher than the width of the sand box. The lifting height must ensure that the sand mold does not come into contact with any obstacles during the 180° rotation process.

[0012] S3, Loosening the rope and unloading: Control the sand mold at the end of the small hook body to slowly fall. When the wire rope at the end of the small hook body is completely loosened, remove the wire rope.

[0013] S4, Aerial Flip: Start the rotary drive motor one used to control the rotation of the large hook body in the crane. The start of the rotary drive motor one will drive the small hook body end to rotate. During the rotation, keep the sand mold posture stable so that the small hook body end faces the original bottom surface of the sand mold. After the rotation is completed, use the steel wire rope at the small hook body end to lift the sand mold again.

[0014] S5, Synchronous Descent: Control the large hook body and the small hook body to descend synchronously and at a uniform speed, ensuring that the sand mold falls smoothly to the target position and completes the flipping action.

[0015] As a further improvement of the present invention, in step S4, a traveling connecting plate is fixedly connected to the top and bottom of the traveling trolley, a protective frame is fixedly connected to the center of the top of the traveling connecting plate, an annular sliding groove is provided at the bottom of the traveling connecting plate, and a through hole is provided at the bottom of the protective frame at the top of the traveling connecting plate. Through the structural design of the traveling connecting plate, the protective frame, the annular sliding groove, and the through hole, rigid linkage and precise guidance between the rotary drive motor and the sand mold turning mechanism are achieved. The traveling connecting plate provides structural support, the protective frame isolates external interference, the annular sliding groove ensures a smooth and unbiased rotation trajectory, and the through hole optimizes the pipeline layout. Together, they ensure that the sand mold is stable and its trajectory is controllable during the 180° turning process, and the landing point accuracy of the sand mold is improved by 40% during synchronous descent. This effectively avoids the risk of collision and attitude deviation during the turning process, and significantly improves the safety and operational accuracy of turning large cast steel sand molds.

[0016] As a further improvement of the present invention, in step S3, the slow descent of the sand mold at the end of the small hook body is achieved by starting the second rotary drive motor. A threaded post II is fixedly connected to the top of the small hook body, and a separation connecting block is provided at the top of the small hook body. A threaded groove II is formed at the bottom of the separation connecting block, and the threaded post II is threadedly connected inside the threaded groove II. Through the rigid threaded connection design between the second rotary drive motor and the threaded post II and threaded groove II, precise control and rapid assembly / disassembly of the sand mold descent at the end of the small hook are achieved. The motor drive ensures graded adjustment of the descent speed, the threaded connection provides an impact torque of ≥500 N·m, and the separation connecting block structure supports rapid replacement of the wire rope. This ensures both the safety and stability of the unloading process and improves equipment maintenance efficiency and operational flexibility.

[0017] As a further improvement of the present invention, a series rope is fixedly connected to the top of the separating connecting block. The output end of the second rotary drive motor is close to the series rope, and a rotating coiling block is fixedly connected to the output end of the second rotary drive motor. The end of the series rope away from the separating connecting block is fixedly connected to the surface of the rotating coiling block. The series rope is wound around the surface of the rotating coiling block. Rope plate one and rope plate two are rotatably connected to the outer sides of the rotating coiling block, respectively. The second rotary drive motor is fixedly connected inside rope plate one. Through the winding linkage design of the series rope and the rotating coiling block, combined with the precise drive control of the second rotary drive motor, the tension adaptive adjustment and anti-slip rope protection during the falling process of the small hook end sand mold are realized. Rope plates one and two on both sides of the rotating coiling block form a guide limit to ensure that the winding trajectory of the series rope is stable and without deviation. With the rigid connection structure of the threaded column two, the synchronization of wire rope winding and unwinding during the unloading process is ensured, and the problems of rope skipping and slippage that are prone to occur in traditional single rope connections are avoided.

[0018] As a further improvement of the present invention, a central connecting block is fixedly connected to the middle of rope plate one and rope plate two, a connecting rotating block is fixedly connected to the top of the central connecting block, and a sliding block is fixedly connected to the top of the sliding block. The sliding block is slidably connected inside the annular sliding groove. Through the sliding guide design of the central connecting block, the connecting rotating block, and the annular sliding groove, precise trajectory control and dynamic stability improvement of rope plates one and two are achieved. The sliding constraint of the sliding block in the annular sliding groove ensures that there is no radial offset of the connecting structure during the flipping process. The radial runout of the connecting rotating block when transmitting torque is ≤0.1mm. The central connecting block provides a tensile strength of ≥3000N, making the rope system run more smoothly and increasing the impact resistance by 50% when the sand mold flips, while reducing the wear of the wire rope.

[0019] As a further improvement of the present invention, in step S4, a threaded post is fixedly connected to the top of the large hook body, a central rotating block is provided at the top of the large hook body, a connecting strip is fixedly connected to the side of the central rotating block near the connecting rotating block, the end of the connecting strip away from the central rotating block is fixedly connected to the side of the connecting rotating block, a threaded groove is opened at the bottom of the central rotating block, the threaded post is threadedly connected to the inside of the threaded groove, a connecting rod is fixedly connected to the top of the central rotating block, the output end of the rotary drive motor is located inside the through hole, the connecting rod is fixedly connected to the output end of the rotary drive motor, and the rotary drive motor is located inside the protective frame. Through the rigid threaded connection of the threaded post and the threaded groove, the synchronous linkage design of the connecting strip, and the axial integrated layout of the rotary drive motor, efficient torque transmission and dynamic balance control of the sand mold flipping at the large hook end are achieved. The threaded connection provides impact-resistant torque, the rigid connection of the connecting strip ensures that the central rotating block and the connecting rotating block rotate synchronously without deviation, and the rotary drive motor is built into the protective frame, which isolates external interference and optimizes the spatial layout, thereby improving the torque transmission efficiency during sand mold flipping.

[0020] As a further improvement of the present invention, in step S1, the wire rope is fixed using a figure-eight winding method. A rubber anti-slip pad is added to the contact area between the large hook body and the wire rope. The rubber anti-slip pad is used to increase the coefficient of friction. The lifting point of the small hook body is calculated using the center of gravity of the sand mold. Three positioning lines (upper, middle, and lower) are marked on the side of the sand mold. These three positioning lines are used to ensure that the initial balance during lifting is ≤2°. Through the figure-eight winding method, the rubber anti-slip pad, the center of gravity calculation of the lifting point, and the three-point positioning line design, anti-slip reinforcement and precise control of lifting balance during the hoisting and fixing process are achieved. The figure-eight winding improves structural stability, and the rubber anti-slip pad increases the coefficient of friction, effectively preventing the wire rope from slipping.

[0021] As a further improvement of the present invention, in step S2, the lifting speed is controlled in three stages: an initial speed of 0.1 m / s when the sand mold is within 0.5 m above the ground, a middle speed of 0.3 m / s at the safe height, and a final speed of 0.2 m / s when approaching the target height. The lowest point of the sand mold is at least 100 mm above the ground. Through this three-stage speed regulation and the safety height design (the lowest point of the sand mold being at least 100 mm above the ground), dynamic optimization and collision risk prevention during the lifting process are achieved.

[0022] As a further improvement of the present invention, in step S3, the falling speed of the small hook body is linked to the tension of the wire rope. When the tension sensor detects that the tension has dropped to 30% of its initial value, a deceleration mode is automatically triggered. The criterion for determining that the wire rope is completely slack is that the wire rope sag is ≥150mm and there is no swaying tendency, as confirmed by the visual recognition system. Through dual-modal control of the tension sensor and the visual recognition system, intelligent linkage between tension and speed and accurate determination of slack state are achieved during the falling process of the small hook end sand mold. The automatic triggering of the deceleration mode when the tension drops to 30% of its initial value avoids impact damage caused by excessive slack in the wire rope. The visual system ensures the accuracy of slack state confirmation through the composite determination of sag ≥150mm and no swaying tendency.

[0023] Compared with the prior art, the beneficial effects of this invention are as follows:

[0024] 1. The sand mold flips in mid-air without contacting the ground, avoiding the angle control issues caused by ground contact in traditional flipping methods. Furthermore, the flipping process is vibration-free, effectively preventing wet sand molds from sinking and dry sand molds from falling into the mold box and becoming unusable, significantly improving the yield of finished sand molds. It also ensures the stability of the sand mold flipping, reducing the amount of sand box reinforcement required, while preventing cracking during flipping, ensuring dimensional accuracy of the sand mold, and improving the quality of cast steel products. The operation process is simple and efficient, and can be widely applied in production scenarios such as multi-box molding of large cast steel parts, making it suitable for a wide range of applications.

[0025] 2. By using a mechanical rigid connection to achieve synchronous movement of the large hook and the small hook, the problem of posture sway caused by the traditional independent drive of the double hook is completely solved, ensuring that the angle deviation during the large sand mold flipping process is ≤0.5°. Compared with the existing technology, its anti-collision control accuracy is improved.

[0026] 3. The figure-eight winding fixing method combined with the rubber anti-slip pad layer increases the friction coefficient to over 0.8, improving the anti-slip performance compared to the simple lifting ring connection method in the existing technology. At the same time, the three-point positioning baseline enables precise control of the initial balance of lifting to ≤2°.

[0027] 4. By linking a tension sensor with a rotary drive motor, the system automatically triggers a deceleration mode when the wire rope tension drops to 30% of its initial value. Combined with a visual recognition system, the rope is fully slackened when the sag is ≥150mm. This improves efficiency by 60% and safety by 100% compared to manual operation. Furthermore, the single rotary drive motor drives the large and small hooks to rotate synchronously via a rigid threaded connection. With the guidance of an annular sliding groove, it achieves a 180° flipping trajectory accuracy of ≤0.3°, improving flipping stability compared to existing hydraulic drive solutions. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart of the steps of the present invention.

[0030] Figure 2 This is a three-dimensional structural diagram of the flipping device in this invention.

[0031] Figure 3 In this invention Figure 2 A three-dimensional structural diagram of the flipping device from another angle.

[0032] Figure 4 This is a three-dimensional structural diagram of the overhead crane connecting plate and the rotary drive motor in this invention.

[0033] Figure 5 This is a three-dimensional structural diagram of the overhead crane connecting plate and the through hole in this invention.

[0034] Figure 6 This is a three-dimensional structural diagram of the large hook body and the small hook body in this invention.

[0035] Figure 7 This is a three-dimensional structural diagram of the large hook body and the small hook body in the separated state in this invention.

[0036] Figure 8 In this invention Figure 6 A schematic diagram of the three-dimensional structure from another angle.

[0037] Figure 9 This is a three-dimensional structural diagram of the rotary drive motor 2 and the rotating coiling block in this invention.

[0038] In the diagram: 101, crane connecting plate; 102, protective frame; 103, annular sliding groove; 104, through hole; 201, rotary drive motor one; 202, connecting rod; 203, central rotating block; 204, large hook body; 205, connecting strip; 206, connecting rotating block; 207, sliding block; 208, central connecting block; 209, rope plate one; 210, rope plate two; 211, rotary drive motor two; 212, rotating coiling block; 213, series rope; 214, separating connecting block; 215, small hook body; 216, threaded groove one; 217, threaded post one; 218, threaded groove two; 219, threaded post two. Detailed Implementation

[0039] 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.

[0040] Example: A method for smoothly flipping sand molds of large cast steel parts based on synchronous control of large and small hooks, such as... Figure 1 As shown, it includes the following steps:

[0041] S1, Lifting and Fixing: Use the wire rope provided on the large hook body 204 to tighten and fix one end of the sand mold, while using the wire rope provided on the small hook body 215 to lift the other end of the sand mold to form a two-point support. The wire rope is fixed by a figure-eight winding method. A rubber anti-slip pad is added at the contact point between the large hook body 204 and the wire rope to increase the friction coefficient. The lifting point of the small hook body 215 is calculated based on the center of gravity of the sand mold. Three positioning lines (upper, middle, and lower) are marked on the side of the sand mold to ensure that the initial balance during lifting is ≤2°.

[0042] Using the sand mold hoisting and fixing technology as a comparison, the advantages of this invention compared to existing technologies are analyzed in detail. A detailed comparison table is shown below:

[0043] Table 1 Comparison of Technical Solutions for Sand Mold Lifting and Fixing

[0044]

[0045] Based on Table 1 above, it can be concluded that the present invention, through multiple measures such as two-point support with large and small hooks, figure-eight winding, rubber anti-slip pad layer, center of gravity calculation and three-point positioning line, comprehensively optimizes the four dimensions of fixing method, contact protection, balance pre-control and posture accuracy during the hoisting and fixing stage. This achieves high reliability, high anti-slip, high stability and high precision in the initial hoisting state of sand molds, eliminates hidden dangers such as slippage, off-center loading and overturning from the source, and greatly improves the stability and safety of large sand molds before hoisting.

[0046] S2, Lifting in mid-air: Control the large hook body 204 and the small hook body 215 to lift the sand mold synchronously, so that the overall height of the sand mold is higher than the width of the sand box. The lifting height must ensure that the sand mold does not come into contact with any obstacles during the 180° rotation. The lifting speed is controlled in three stages: an initial speed of 0.1 m / s when within 0.5 m of the ground, a middle speed of 0.3 m / s at the safe height, and a final speed of 0.2 m / s when approaching the target height. The lowest point of the sand mold must be at least 100 mm above the ground.

[0047] Using the speed and safety control of the sand mold lifting process as a comparison condition, the advantages of this invention compared to existing technologies are analyzed in detail. The specific comparison table is as follows:

[0048] Table 2 Comparison of Speed ​​and Safety Control in Sand Mold Lifting Process

[0049]

[0050] Based on Table 2 above, it can be concluded that the simultaneous lifting of large and small hooks, three-stage graded speed adjustment, and quantitative safety height control during the aerial lifting stage effectively reduce the impact and vibration disturbance of starting and stopping compared to the traditional uniform speed and manual visual lifting method. This ensures that the sand mold has stronger synchronization, smoother operation, and more sufficient safety redundancy during the lifting process, protecting the sand mold structure from damage and providing a stable and reliable aerial posture for the subsequent 180° flip.

[0051] S3, Unloading with slack rope: The sand mold at the end of the small hook body 215 is slowly lowered. When the wire rope at the end of the small hook body 215 is completely slack, the wire rope is removed. The slow lowering of the sand mold at the end of the small hook body 215 is achieved by starting the rotary drive motor 211. A threaded post 219 is fixedly connected to the top of the small hook body 215. A separation connecting block 214 is provided at the top of the small hook body 215. A threaded groove 218 is opened at the bottom of the separation connecting block 214. The threaded post 219 is threadedly connected to the inside of the threaded groove 218. A series rope 213 is fixedly connected to the top of the separating connecting block 214. The output end of the rotary drive motor 211 is close to the series rope 213. A rotating coiling block 212 is fixedly connected to the output end of the rotary drive motor 211. The end of the series rope 213 away from the separating connecting block 214 is fixedly connected to the surface of the rotating coiling block 212. The series rope 213 is wound around the surface of the rotating coiling block 212. Rope plate 1 209 and rope plate 210 are rotatably connected to the outer sides of the rotating coiling block 212, respectively. The rotary drive motor 211 is fixedly connected inside the rope plate 1 209. A central connecting block 208 is fixedly connected to the middle of the rope plate 1 209 and the rope plate 210. A connecting rotating block 206 is fixedly connected to the top of the central connecting block 208. A sliding block 207 is fixedly connected to the top of the sliding block 207. The sliding block 207 is slidably connected inside the annular sliding groove 103. The falling speed of the small hook body 215 is linked to the tension of the wire rope. When the tension sensor detects that the tension has dropped to 30% of the initial value, the deceleration mode is automatically triggered. The criterion for determining that the wire rope is completely slack is that the sag of the wire rope is ≥150mm and there is no swaying trend, as confirmed by the visual recognition system.

[0052] Using the precision and controllability of the sand mold unloading process as a comparison criterion, the advantages of this invention compared to existing technologies are analyzed in detail. The specific comparison table is as follows:

[0053] Table 3 Comparison of Precision and Controllability in the Unloading Process of Sand Molds via Loose Rope

[0054]

[0055] Based on Table 3 above, it can be concluded that the rope slack unloading process is automated, precise, and safe through a motor-driven winding mechanism, tension-linked deceleration, visual + tension dual-criteria slack determination, and threaded rigid connection. This solves the problems of uncontrollable speed, inaccurate judgment, easy sudden fall, and easy hook detachment in traditional manual operation, making the unloading process smooth and impact-free, the status judgment reliable, and the structural connection firm, significantly improving the consistency of operation and the level of inherent safety.

[0056] S4, Aerial Flip: Start the rotary drive motor 201 used to control the rotation of the large hook body 204 in the gantry crane. The start of the rotary drive motor 201 will drive the small hook body 215 to rotate. During the rotation, the sand mold is kept stable, so that the small hook body 215 faces the original bottom surface of the sand mold. After the rotation is completed, the sand mold is lifted again by the steel wire rope at the end of the small hook body 215. The top and bottom of the gantry crane are fixedly connected to the gantry crane connecting plate 101. The top center of the gantry crane connecting plate 101 is fixedly connected to the protective frame 102. The bottom of the gantry crane connecting plate 101 is provided with an annular sliding groove 103. The top of the gantry crane connecting plate 101 is provided with a through hole 104 at the bottom of the protective frame 102. A threaded post 217 is fixedly connected to the top of the hook body 204. A central rotating block 203 is provided at the top of the hook body 204. A connecting strip 205 is fixedly connected to the side of the central rotating block 203 near the connecting rotating block 206. The end of the connecting strip 205 away from the central rotating block 203 is fixedly connected to the side of the connecting rotating block 206. A threaded groove 216 is opened at the bottom of the central rotating block 203. The threaded post 217 is threadedly connected to the inside of the threaded groove 216. A connecting rod 202 is fixedly connected to the top of the central rotating block 203. The output end of the rotary drive motor 201 is located inside the through hole 104. The connecting rod 202 is fixedly connected to the output end of the rotary drive motor 201. The rotary drive motor 201 is located inside the protective frame 102.

[0057] Using the synchronous control and attitude stability of the sand mold aerial flipping process as a comparison condition, the advantages of the present invention compared with the prior art are analyzed in detail. The specific comparison table is as follows:

[0058] Table 4 Comparison of Synchronous Control and Attitude Stability During Sand Mold Aerial Tilting

[0059]

[0060] Based on Table 4 above, it can be concluded that the aerial flipping, as a core innovative element, adopts a single-drive source rigid linkage between large and small hooks, mechanical synchronous constraints, and a ring slide rail guide to achieve height synchronization, constant attitude, and controllable trajectory of the two hooks during the flipping process. This completely solves the pain points of traditional independent dual-hook drives, such as asynchronous operation, large attitude fluctuations, and strong flipping impact. It ensures that the sand mold has no swaying, vibration, or overturning risk during 180° flipping, thus maximizing the protection of the integrity of large cast steel sand molds.

[0061] S5, Synchronous Fall: Control the large hook body 204 and the small hook body 215 to fall synchronously and at a uniform speed, ensuring that the sand mold falls smoothly to the target position and completes the flipping action.

[0062] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for smooth flipping of sand molds for large cast steel parts based on synchronous control of large and small hooks, characterized in that, Specifically, the steps include the following: S1, hoisting and fixing: use the wire rope set on the large hook body (204) to tighten and fix one end of the sand mold, and at the same time use the wire rope set on the small hook body (215) to lift the other end of the sand mold to form two-point support; S2, lifting in mid-air: control the large hook body (204) and the small hook body (215) to lift the sand mold synchronously, so that the overall height of the sand mold is higher than the width of the sand box. The lifting height must meet the requirement that the sand mold does not come into contact with any obstacles during the 180° rotation process. S3, unloading by slack rope: slowly lower the sand mold at the end of the small hook body (215), and remove the wire rope when the wire rope at the end of the small hook body (215) is completely slack. S4, Flip in mid-air: Start the rotary drive motor 1 (201) used to control the rotation of the large hook body (204) in the crane. The start of the rotary drive motor 1 (201) will drive the small hook body (215) end to rotate. During the rotation, keep the sand mold posture stable so that the small hook body (215) end faces the original bottom surface of the sand mold. After the rotation is completed, use the wire rope at the end of the small hook body (215) to lift the sand mold again. S5, Synchronous Fall: Control the large hook body (204) and the small hook body (215) to fall synchronously and at a uniform speed, ensuring that the sand mold falls smoothly to the target position and completes the flipping action.

2. The method for smooth flipping of sand molds for large cast steel parts based on synchronous control of large and small hooks as described in claim 1, characterized in that: In step S4, a vehicle connecting plate (101) is fixedly connected to the top and bottom of the vehicle. A protective frame (102) is fixedly connected to the center of the top of the vehicle connecting plate (101). An annular sliding groove (103) is provided at the bottom of the vehicle connecting plate (101). A through hole (104) is provided at the top of the vehicle connecting plate (101) at the bottom of the protective frame (102).

3. The method for smooth flipping of sand molds for large cast steel parts based on synchronous control of large and small hooks as described in claim 2, characterized in that: In step S3, the sand mold at the end of the small hook body (215) slowly falls by starting the second rotary drive motor (211). The top end of the small hook body (215) is fixedly connected to the second threaded post (219). The top end of the small hook body (215) is provided with a separation connecting block (214). The bottom end of the separation connecting block (214) is provided with a second threaded groove (218). The second threaded post (219) is threadedly connected to the inside of the second threaded groove (218).

4. The method for smooth flipping of sand molds for large cast steel parts based on synchronous control of large and small hooks as described in claim 3, characterized in that: The top of the separating connecting block (214) is fixedly connected to a series rope (213). The output end of the second rotary drive motor (211) is close to the series rope (213). The output end of the second rotary drive motor (211) is fixedly connected to a rotating coiling block (212). One end of the series rope (213) away from the separating connecting block (214) is fixedly connected to the surface of the rotating coiling block (212). The series rope (213) is wrapped around the surface of the rotating coiling block (212). Rope plate one (209) and rope plate two (210) are rotatably connected to the outer sides of the rotating coiling block (212). The second rotary drive motor (211) is fixedly connected inside the rope plate one (209).

5. The method for smooth flipping of sand molds for large cast steel parts based on synchronous control of large and small hooks as described in claim 4, characterized in that: A central connecting block (208) is fixedly connected to the middle of the first rope plate (209) and the second rope plate (210). A connecting rotating block (206) is fixedly connected to the top of the central connecting block (208). A sliding block (207) is fixedly connected to the top of the sliding block (207). The sliding block (207) is slidably connected inside the annular sliding groove (103).

6. The method for smooth flipping of sand molds for large cast steel parts based on synchronous control of large and small hooks as described in claim 5, characterized in that: In step S4, a threaded post (217) is fixedly connected to the top of the large hook body (204), a central rotating block (203) is provided at the top of the large hook body (204), a connecting strip (205) is fixedly connected to the side of the central rotating block (203) near the connecting rotating block (206), and the end of the connecting strip (205) away from the central rotating block (203) is fixedly connected to the side of the connecting rotating block (206). A threaded groove (216) is provided at the bottom of the central rotating block (203), the threaded post (217) is threadedly connected to the inside of the threaded groove (216), a connecting rod (202) is fixedly connected to the top of the central rotating block (203), the output end of the rotary drive motor (201) is located inside the through hole (104), the connecting rod (202) is fixedly connected to the output end of the rotary drive motor (201), and the rotary drive motor (201) is located inside the protective frame (102).

7. The method for smooth flipping of sand molds for large cast steel parts based on synchronous control of large and small hooks as described in claim 1, characterized in that: In step S1, the wire rope is fixed by a figure-eight winding method. A rubber anti-slip pad is added to the contact area between the large hook body (204) and the wire rope. The rubber anti-slip pad is used to increase the friction coefficient. The lifting point of the small hook body (215) is calculated by the center of gravity of the sand mold. Three positioning lines are marked on the side of the sand mold. The three positioning lines are used to ensure that the balance is ≤2° in the initial lifting stage.

8. The method for smooth flipping of sand molds for large cast steel parts based on synchronous control of large and small hooks as described in claim 1, characterized in that: In step S2, the lifting speed is controlled in three stages: an initial speed of 0.1 m / s when the sand mold is within 0.5 m above the ground, a middle speed of 0.3 m / s at the safe height, and a final speed of 0.2 m / s when the sand mold is close to the target height. The lowest point of the sand mold is ≥ the width of the sand box + 100 mm from the ground.

9. The method for smooth flipping of sand molds for large cast steel parts based on synchronous control of large and small hooks as described in claim 1, characterized in that: In step S3, the falling speed of the small hook body (215) is linked to the tension of the wire rope. When the tension sensor detects that the tension has dropped to 30% of the initial value, the deceleration mode is automatically triggered. The criterion for determining that the wire rope is completely slack is that the sag of the wire rope is ≥150mm and there is no swinging trend, as confirmed by the visual recognition system.

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