Double electric hoist hoisting system and hoisting control method

Abstract

The present application relates to a kind of double electric hoist hoisting system and hoisting control method.The system includes two electric hoists, balance beam, two floating detection lifting point modules, two clamping assemblies and control unit.Floating detection lifting point module is spaced along the length direction of balance beam, including mounting seat, floating seat and displacement detection piece;Floating seat can be elastically floated relative to mounting seat, and its upper portion is connected with the hook of corresponding electric hoist;Displacement detection piece is used to detect the movement amount of floating seat relative to mounting seat.Two clamping assemblies are respectively connected with corresponding floating seat, and are used to clamp the two ends of load, so that load load is transmitted to corresponding floating seat.Control unit controls two electric hoists to carry out differential adjustment according to the difference of the movement amount of two floating seats.The system can correct deviation based on the actual stress state of lifting point side, reduce the risk of balance beam deflection, load swing and workpiece impact, improve the stability and safety of double electric hoist hoisting.

Description

Technical Field

[0001] This invention relates to the field of lifting and hoisting equipment technology, and in particular to a dual electric hoist hoisting system and hoisting control method. Background Technology

[0002] In automated hoisting operations of large workpieces and fixtures, dual electric hoists combined with a balance beam have strong structural load-bearing capacity and uniform force distribution, and are widely used in precision machining and workpiece transfer scenarios. For large-sized, heavy, or unpredictable loads, the force distribution and lifting synchronization of the two lifting points directly determine the stability of the hoisting posture and the safety of the operation.

[0003] In actual hoisting operations, asynchronous force distribution and inconsistent lifting strokes often occur at the two lifting points, which can easily cause the balance beam to tilt and the load to swing eccentrically. For product jigs containing precision workpieces, sand cores, and other vulnerable parts, tilting and hoisting impacts can cause workpiece slippage, collisions, or even breakage and detachment, posing significant safety hazards. Therefore, accurate and stable synchronous correction is a core technical requirement for precision hoisting.

[0004] Currently, the synchronous control of dual electric hoists mostly relies on motor encoders and frequency converters to synchronously regulate the motor speed and revolutions. This control method is a closed-loop control at the motor end, mainly ensuring that the theoretical output motion of the two motors is consistent, but it is difficult to directly obtain the actual displacement and stress state at the lifting point. Due to objective physical errors in the lifting system, such as the elastic deformation of the wire rope, the assembly gap of the lifting device, the load eccentricity, and the lag in the mechanism response, the theoretical rotation output of the motor is difficult to be completely equivalently converted into the actual lifting stroke at the lifting point. This leads to the possibility that even if the operating parameters of the two motors are synchronized, the actual lifting displacement and stress state of the two lifting points may still deviate, making it difficult to identify minor uneven stress problems in the early stage of lifting, ultimately resulting in insufficient lifting synchronization accuracy.

[0005] Furthermore, existing technologies generally employ a dual-sided synchronous chasing and correction mode. When deviations are detected on both sides, the electric hoists on both sides need to be accelerated and decelerated synchronously for correction. Under conditions of load eccentricity and uneven force on the lifting points, this correction method easily leads to frequent dynamic switching of the driving states on both sides, resulting in continuous mechanical impacts and swaying of the lifting beam. This can easily cause the fixture to loosen and the load to slip and shift, significantly increasing the risk of breakage of precision workpieces. Summary of the Invention

[0006] Therefore, the purpose of this invention is to address the problems of existing dual-electric hoist lifting systems that rely primarily on motor parameters for synchronous control, which makes it difficult to reflect the actual working conditions at the lifting points, resulting in insufficient synchronous control accuracy. Furthermore, the chasing-style correction method is prone to causing mechanical impact, beam swaying, loose clamping, and workpiece damage. This invention provides a dual-electric hoist lifting system and its control method. By collecting floating displacement data from both lifting points for differentiated correction and control, this invention reduces lifting deviations caused by mismatch between motor control and the actual state at the lifting points, lowers the risk of mechanical impact and load swaying during lifting, and improves the stability and safety of lifting operations involving precision fixtures and fragile workpieces.

[0007] To solve the above-mentioned technical problems, in a first aspect, the present invention provides a dual electric hoist lifting system, comprising: Two electric hoists; Balance beam; Two floating detection lifting point modules are spaced apart along the length of the balance lifting beam; each floating detection lifting point module includes a mounting base, a floating seat, and a displacement detection component; the floating seat is assembled inside the mounting base and floats elastically relative to the mounting base, and its upper part is connected to the hook of the corresponding electric hoist; the displacement detection component is used to detect the amount of movement of the floating seat relative to the mounting base; Two clamping components are respectively set for the two floating detection lifting point modules and are respectively connected to the floating seat. They can switch to the clamping state when the floating seat moves upward relative to the mounting seat to clamp both ends of the load. The control unit is connected to the two electric hoists and the two displacement detection devices. The control unit is used to control the two electric hoists to move at different speeds when the absolute value of the difference in the movement of the two floating seats exceeds the allowable displacement difference threshold, until the absolute value of the difference in the movement of the two floating seats falls back to the threshold range, and then the two electric hoists resume moving at a preset speed.

[0008] In one embodiment of the present invention, the floating detection suspension point module is provided with a guide structure; the guide structure includes two vertical guide columns and a guide sleeve, the two ends of the guide columns are respectively fixed to the top plate and the bottom plate of the mounting base, and the guide sleeve is fixed in the floating base and slidably fitted onto the guide columns.

[0009] In one embodiment of the present invention, the floating detection suspension point module is provided with an elastic support member, the elastic support member including a first elastic member and a second elastic member, the second elastic member having a stiffness greater than that of the first elastic member; the two ends of the first elastic member respectively abut against the top plate of the mounting base and the floating base; one end of the second elastic member is connected to the top plate, and the other end has an initial gap with the floating base; the floating base compresses the first elastic member first when it moves upward, and the second elastic member is simultaneously compressed after the initial gap is eliminated.

[0010] In one embodiment of the present invention, one end of the guide post is provided with a limiting connector that is connected to the top plate, and the outer diameter of the limiting connector is larger than the outer diameter of the main body of the guide post.

[0011] In one embodiment of the present invention, the displacement detection element includes a displacement sensor and a detection protrusion. The displacement sensor is disposed on the side plate of the mounting base, and the detection protrusion is disposed on the side of the floating base facing the displacement sensor. When the floating base moves relative to the mounting base, the displacement sensor detects the displacement change of the detection protrusion in real time.

[0012] In one embodiment of the present invention, each clamping assembly includes a hinge seat and a gripper; the hinge seat is fixed to the balance beam; the gripper includes a drive arm, a clamping arm, and a hinge portion between the two, wherein the drive arm and the clamping arm are arranged at an obtuse angle. The hinge is hinged to the hinge seat; the free end of the clamping arm forms a clamping part; the driving arm is provided with a waist-shaped groove; the floating seat is provided with a connecting shaft, the bottom end of the connecting shaft is provided with a rotating shaft, and the rotating shaft passes through the waist-shaped groove and can slide along the groove.

[0013] In one embodiment of the present invention, a trigger portion is formed at the end of the drive arm, a bracket is provided below the balance beam, a proximity switch is provided on the bracket, and the proximity switch is electrically connected to the control unit; When the gripper swings to the preset gripping position, the trigger part enters the detection range of the proximity switch, and the proximity switch outputs a gripping position signal to the control unit.

[0014] In one embodiment of the present invention, the mounting base is provided with a positioning pin, which is movable between a holding position and a releasing position; in the holding position, the positioning pin engages with a positioning hole on the side wall of the floating base to hold the floating base at a preset height and to keep the clamping assembly in an open state. In the released position, the positioning pin releases its hold on the floating seat, allowing the floating seat to move upward relative to the mounting base under the lifting load of the electric hoist, thereby driving the clamping assembly to clamp the load.

[0015] In one embodiment of the present invention, the balance beam is provided with a positioning support, one end of which is fixedly connected to the balance beam and the other end is provided with a positioning hole; the load is a product fixture containing a workpiece, the product fixture is provided with a positioning post, the positioning post is inserted into the positioning hole to limit the relative position between the balance beam and the product fixture.

[0016] In a second aspect, the present invention provides a dual-electric hoist hoisting control method, using the above-mentioned dual-electric hoist hoisting system, the control method comprising: The electric hoist is started at a preset speed, pulling the floating seat upward; the rising of the floating seat causes the clamping assembly to clamp the load. During the ascent of the floating seats, the movement of the two floating seats relative to their respective mounting seats is monitored in real time to obtain the first movement and the second movement. Calculate the absolute value of the difference between the first movement amount and the second movement amount. If the absolute value of the difference exceeds a preset threshold, control the electric hoist corresponding to the side with the larger movement amount to pause, and control the electric hoist corresponding to the side with the smaller movement amount to continue lifting until the absolute value of the difference is within the preset threshold range.

[0017] The technical solution of the present invention has the following advantages compared with the prior art: This invention involves installing floating detection lifting point modules between two electric hoists and a balance beam, and connecting the load via clamping assemblies. This allows the loads at both ends of the load to act on corresponding floating seats via the clamping assemblies. Since the floating seats are located in the force transmission path of the lifting points, when one side of the lifting point is stressed first or bears a larger load, the elastic floating amount of that side's floating seat increases accordingly; when that side's lifting point is not yet fully stressed, the floating seat's movement is smaller. Therefore, the difference in movement between the two floating seats reflects the force difference between the two lifting points, providing a basis for the control unit to determine whether the lifting is balanced.

[0018] The correction method of this invention is not based on motor parameters such as motor speed or revolutions, but on the difference in movement between the two floating seats. When the absolute value of this difference exceeds a preset threshold, it indicates a deviation in the force establishment at the two lifting points. At this time, the control unit stops the electric hoist corresponding to the side with larger movement and continues to lift at a preset speed, gradually building up the load on the side with insufficient force until the difference in movement between the two sides returns to the preset threshold range. Thus, this invention does not simply pursue identical output from the two motors, but corrects the deviation based on the actual force state at the lifting point, reducing the tilting of the balance beam and load swaying caused by synchronization at the motor end but asynchrony at the lifting point end.

[0019] The floating seat in this invention can elastically float relative to the mounting base, converting changes in the force on the lifting point into detectable displacement changes. On the one hand, the displacement detection device can directly detect the movement of the floating seat, avoiding the need to rely solely on theoretical motor parameters to calculate the lifting point state; on the other hand, the elastic floating of the floating seat can buffer sudden changes in the load on the lifting point, allowing the load to be transferred more smoothly to the balance beam and the load, reducing rigid impacts, and minimizing the risk of load sway and workpiece damage.

[0020] Compared to existing dual-sided synchronous chasing correction methods, this invention determines which side experiences greater force and which side experiences less force based on the difference in movement, and makes differentiated adjustments to the electric hoists on both sides. This method reduces the drive state switching caused by frequent acceleration and deceleration of the electric hoists on both sides, making the correction process more closely match the actual stress state of the lifting point, thereby reducing the risk of mechanism impact, lifting beam sway, and damage to precision workpieces.

[0021] In summary, this invention can determine the force difference between the two lifting points based on the floating displacement of the lifting point side, and adjust the lifting action of the two electric hoists accordingly, thereby improving the problem that the existing synchronous control at the motor end is difficult to reflect the actual working conditions of the lifting point, and improving the correction accuracy, stability and safety of the load lifting process. Attached Figure Description

[0022] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0023] Figure 1 This is a structural schematic diagram (before lifting) of the dual electric hoist lifting system provided by the present invention. Figure 2 This is a structural schematic diagram of the dual electric hoist lifting system provided by the present invention (lifting in progress); Figure 3 This is a structural schematic diagram of the floating detection suspension point module provided by the present invention; Figure 4 This is a cross-sectional view of the floating detection suspension point module provided by the present invention; Figure 5 This is a schematic diagram of the clamping assembly provided by the present invention; Figure 6 This is a structural schematic diagram of the guide post, the first elastic element, and the second elastic element provided by the present invention; Figure 7 This is a flowchart illustrating the hoisting control method provided by the present invention.

[0024] Explanation of reference numerals in the accompanying drawings: 10. Electric hoist; 11. Upper shackle; 20. Balance beam; 21. Bushing; 30. Floating detection lifting point module; 31. Mounting base; 311. Base plate; 312. Side plate; 313. Support top plate; 32. Floating seat; 321. Lifting lug connection; 3211. Upper lug plate; 3212. Lifting lug pin; 322. Positioning hole; 33. Elastic support component; 331. First elastic component; 332. Second elastic component; 34. Displacement detection component; 341. Displacement sensor; 342. Detection protrusion; 35. 351. Guide structure; 352. Guide sleeve; 353. Limiting connector; 36. Positioning pin; 40. Clamping mechanism; 41. Clamping assembly; 42. Connecting shaft; 421. Rotating shaft; 43. Hinge seat; 44. Gripper; 441. Drive arm; 442. Clamping arm; 443. Hinge part; 444. Waist-shaped groove; 445. Clamping part; 45. Trigger part; 46. Proximity switch; 47. Bracket; 48. Positioning support; 60. Product fixture; 61. Support boss; 611. Lower support surface; 62. Positioning pin. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0026] See Figures 1 to 5 As shown, this embodiment of the invention provides a dual electric hoist lifting system, including two electric hoists 10, a balance lifting beam 20, two floating detection lifting point modules 30, a clamping mechanism 40, and a control unit. This embodiment is mainly applied to load lifting and transfer scenarios such as sand core support fixtures that carry precision or fragile workpieces. The sand core is placed inside the product fixture 60, which supports and limits its movement.

[0027] Two electric hoists 10 are configured one-to-one with two floating detection lifting point modules 30. Before hoisting, the electric hoists 10 move to the preset work position, and the hooks are connected to the floating seats 32 of the floating detection lifting point modules 30. During operation, the two electric hoists 10 work together under the control of the control unit to complete the lifting, transfer, and placement of the product fixture 60. Unlike the method that mainly relies on the motor end operating parameters such as motor encoders and frequency converters to determine the synchronization status, this embodiment obtains the force and displacement status feedback on the lifting point side through the floating detection lifting point modules 30, providing a reliable structural basis for identifying the actual force deviation and synchronization deviation of the two lifting points, and improving the problem of synchronized motor end parameters but asynchronous actual working conditions on the lifting point side.

[0028] Two floating detection suspension point modules 30 are arranged at intervals along the length of the balance suspension beam 20. Each floating detection suspension point module 30 includes a mounting base 31, a floating base 32, an elastic support component 33, and a displacement detection component 34. The four components work together to realize the functions of suspension point force response, elastic displacement, and status detection.

[0029] The mounting base 31 is formed by a base plate 311, two side plates 312, and a supporting top plate 313. The base plate 311 is fixedly installed on the balance beam 20, and the whole structure forms an installation space that allows the floating seat 32 to move vertically. A vertical clearance hole is provided in the middle of the supporting top plate 313. The lifting lug connection part 321 of the top of the floating seat 32 extends vertically through the clearance hole and extends above the supporting top plate 313, so that the hook of the electric hoist 10 can be hooked and assembled through the upper shackle 11. The clearance hole provides clearance space for the vertical floating stroke of the floating seat 32, avoids structural interference between the lifting lug connection part 321 and the supporting top plate 313, and ensures the smooth vertical movement of the floating seat 32.

[0030] The floating seat 32 is assembled inside the mounting base 31 and can move vertically relative to the mounting base 31. The lifting lug connection 321 is composed of an upper lug plate 3211 and a lifting lug pin 3212. The lifting load of the electric hoist 10 can be transferred to the floating seat 32 sequentially through the hook and upper shackle 11, so that the floating seat 32 is connected to the force transmission path of the lifting point. In actual operation, the force state of the lifting point can be converted into the vertical displacement of the floating seat 32: when the lifting point on one side is stressed first or bears a larger load, the upward displacement of the floating seat 32 on that side is relatively large; when the lifting point on one side is stressed later and has not yet fully borne the load, the vertical displacement of the corresponding floating seat 32 is relatively small. Therefore, the difference in the displacement of the two floating seats 32 can reflect the difference in the load establishment sequence and the difference in the load magnitude of the two lifting points. This hook-and-mount assembly structure facilitates the quick docking and assembly of the hook and the floating seat 32, and can also reduce the impact of assembly errors on the vertical movement of the floating seat 32.

[0031] The elastic support 33 is sandwiched between the support top plate 313 and the floating seat 32. When the floating seat 32 is loaded and moves upward, it can compress the elastic support 33 to produce elastic deformation. On the one hand, the elastic support 33 causes the floating seat 32 to produce detectable elastic displacement with the change of the load at the lifting point, providing a detection basis for the displacement detection device 34 to identify the force deviation at the lifting point. On the other hand, the elastic support 33 can play a buffering role when there are sudden load changes or start-stop impacts during the lifting process, so that the load at the lifting point is transferred to the balance beam 20 and the product jig 60 more smoothly, reducing the impact of rigid impact on the balance beam 20, the product jig 60 and the internal precision workpiece.

[0032] The displacement detection component 34 is used to detect the vertical movement of the floating seat 32 relative to the mounting base 31 in real time. In this embodiment, the status feedback of the lifting point is obtained by detecting the actual movement of the floating seat 32, rather than indirectly calculating the synchronization status of the lifting point by relying solely on motor end operating parameters such as motor speed, revolutions, or current, which effectively improves the adaptability to on-site lifting conditions.

[0033] The clamping mechanism 40 includes two sets of clamping components 41, which are arranged one-to-one with two floating detection lifting point modules 30, respectively engaging with the two ends of the product fixture 60. Each set of clamping components 41 is fixedly connected to the corresponding floating seat 32 via a connecting shaft 42, which vertically passes through the balance lifting beam 20. Through this connection structure, the load at both ends of the product fixture 60 can be transferred to the corresponding floating seat 32 through the clamping components 41, so that the displacement of the floating seat 32 can reflect the load establishment status of the corresponding lifting point.

[0034] Based on the aforementioned linkage structure, the vertical movement of the floating seat 32 can drive the connecting shaft 42 to rise and fall, thereby driving the clamping assembly 41 to move. Specifically, when the floating seat 32 moves upward, it causes the clamping assembly 41 to enter the clamping state; after the product fixture 60 is positioned, the floating seat 32 falls back under the action of the elastic support 33, causing the clamping assembly 41 to release from the supporting state. This structure realizes the linkage of establishing the lifting point force, the elastic floating of the floating seat 32, and the attitude switching of the clamping assembly 41. It can establish a load-bearing connection between the product fixture 60 and the lifting system in the early stage of lifting, without the need for an additional independent drive mechanism.

[0035] The control unit is electrically connected to two electric hoists 10 and two sets of displacement detection devices 34 to achieve data acquisition and motion control. After the hoisting starts, the control unit controls the two electric hoists 10 to lift at a preset speed, and the lifting load is gradually applied to the floating seat 32 and compresses the elastic support 33. Since the amount of compression of the elastic support 33 in the elastic deformation range corresponds to the load on the lifting point, the difference in the amount of movement of the floating seats 32 on both sides can characterize the difference in the load on both sides and the difference in the timing of load establishment. The control unit uses this difference in movement as the basis for correction, rather than only using the motor end command or motor operating parameters as the basis for synchronization judgment, so as to better fit the on-site working conditions such as wire rope elastic deformation, mechanism response lag, and jig off-center loading.

[0036] See Figures 3 to 4 As shown, the floating detection suspension point module 30 also has a guide structure 35, which consists of a vertically fixed guide post 351 and a guide sleeve 352 assembled on the floating seat 32. The guide sleeve 352 slides vertically along the guide post 351, which can limit the lateral offset and tilting swing of the floating seat 32, so that the floating seat 32 mainly performs vertical movement. This not only helps to ensure the accuracy of displacement detection data, but also reduces the risk of movement jamming and off-center wear of the connecting shaft 42.

[0037] Further, see Figures 3 to 4 As shown, a limiting connector 353 is provided at the upper end of the guide column 351. The limiting connector 353 is connected to the supporting top plate 313, and the outer diameter of the limiting connector 353 is larger than the outer diameter of the main body of the guide column 351. A clearance is reserved between the floating seat 32 and the limiting connector 353 during normal working stroke to meet the requirements of detection and clamping actions. When the floating seat 32 moves upward to the preset stroke position under the traction of the electric hoist 10, the top surface of the floating seat 32 abuts against the bottom surface of the limiting connector 353. At this time, the limiting connector 353 restricts the floating seat 32 from continuing to move upward, achieving mechanical limiting and reducing the risk of structural collision.

[0038] See Figure 6 As shown, this invention employs a two-stage elastic support structure with differentiated stiffness. The elastic support member 33 includes a first elastic member 331 with lower stiffness and a second elastic member 332 with higher stiffness. The first elastic member 331 is sleeved on the outside of the guide post 351, with its two ends abutting against the support top plate 313 and the floating seat 32, respectively. The second elastic member 332 is sleeved on the outside of the first elastic member 331, with its lower end having an initial gap with the floating seat 32 to accommodate the clamping stroke, allowing it to participate in compression after the initial gap is eliminated. In other embodiments, the second elastic member 332 can also be located adjacent to the outside of the first elastic member 331, as long as it can participate in compression after the initial gap is eliminated.

[0039] During the pre-tensioning and lifting phase, before the product fixture 60 detaches from the workstation support surface, the floating seat 32 compresses the first elastic element 331 as it moves upward. The first elastic element 331 has relatively low stiffness, allowing the floating seat 32 to experience a significant floating stroke. This facilitates the displacement detection element 34 in capturing initial force deviations and adapts to the clamping stroke of the clamping assembly 41, driving the grippers to gradually reach their pre-clamping position. When the clamping assembly 41 approaches its final clamping position, the initial gap of the second elastic element 332 is eliminated. As the product fixture 60 gradually bears the load, the second elastic element 332 participates in the compression, increasing the overall support stiffness through its greater stiffness and suppressing excessive displacement of the floating seat 32. This two-stage elastic structure balances initial detection sensitivity with subsequent load-bearing stability, buffering the impact of sudden loads on the workpiece and equipment.

[0040] See Figures 3 to 4 As shown, the displacement detection component 34 includes a displacement sensor 341 and a detection protrusion 342. The displacement sensor 341 is fixedly mounted on the side plate 312 of the mounting base 31, and the detection protrusion 342 is fixedly mounted on the side of the floating base 32 facing the displacement sensor 341.

[0041] When the floating seat 32 moves vertically relative to the mounting base 31, the detection protrusion 342 moves synchronously with the floating seat 32. The displacement sensor 341 detects the positional change of the detection protrusion 342 and sends the detection result to the control unit. The control unit determines whether the load-bearing state of the two suspension points is consistent based on the difference in the amount of movement of the two floating seats 32, thereby providing a basis for subsequent differential speed compensation.

[0042] In this embodiment, the displacement sensor 341 may be a laser displacement sensor, a magnetostrictive displacement sensor, an LVDT displacement sensor, or other sensors capable of detecting relative displacement.

[0043] See Figures 3 to 5 As shown, each clamping assembly 41 includes a hinge seat 43 and a gripper 44. The hinge seat 43 is fixed to the balance beam 20. The gripper 44 includes a drive arm 441, a clamping arm 442, and a hinge portion 443 connecting the drive arm 441 and the clamping arm 442. An obtuse angle structure is formed between the drive arm 441 and the clamping arm 442. The hinge portion 443 is hinged to the hinge seat 43. A rotating shaft 421 is provided at the lower end of the connecting shaft 42. The drive arm 441 is provided with a waist-shaped groove 444. The rotating shaft 421 passes through the waist-shaped groove 444 and can move relative to it along the waist-shaped groove 444.

[0044] When the floating seat 32 moves upward, the connecting shaft 42 drives the rotating shaft 421 to move upward synchronously. The rotating shaft 421 applies a driving force to the gripper 44 through the waist-shaped groove 444, causing the gripper 44 to swing around the hinge seat 43. As the gripper 44 swings, the gripping part 445 formed at the lower end of the gripping arm 442 gradually approaches the product fixture 60 and eventually enters the gripping position.

[0045] The clamping assembly 41 can directly complete the clamping action by using the upward movement of the floating seat 32, without the need for additional independent clamping drive mechanisms such as cylinders and motors, thereby realizing the linkage between lifting point detection and clamping action.

[0046] Further, see Figure 1 As shown, a bushing 21 is fixed in the mounting hole of the balance beam 20. The connecting shaft 42 passes through the bushing 21 and slides vertically. The bushing 21 can guide and radially limit the connecting shaft 42, reduce lateral offset and jamming wear, and ensure stable operation of the clamping assembly 41 and smooth load transmission.

[0047] Furthermore, such as Figure 5 As shown, a trigger part 45 is formed at the end of the drive arm 441, a bracket 47 is provided below the balance beam 20, a proximity switch 46 is provided on the bracket 47, and the proximity switch 46 is electrically connected to the control unit.

[0048] When the floating seat 32 drives the connecting shaft 42 to move upward, the connecting shaft 42 drives the gripper 44 to swing around the hinge seat 43 via the rotating shaft 421 and the waist-shaped groove 444. During the swinging of the gripper 44, the trigger part 45 at the end of the drive arm 441 moves synchronously. When the gripper 44 swings to the preset clamping position, the trigger part 45 enters the detection range of the proximity switch 46, and the proximity switch 46 outputs a clamping position signal to the control unit.

[0049] See Figure 4 and Figure 5 As shown, the product fixture 60 is provided with a supporting boss 61. The supporting boss 61 has a lower supporting surface 611. The clamping part 445 has a cylindrical supporting surface. When the gripper 44 swings to the clamping position, the cylindrical supporting surface is located below the supporting boss 61 and abuts against the lower supporting surface 611. In this embodiment, a supporting fit relationship is formed between the cylindrical supporting surface and the lower supporting surface 611. When the product fixture 60 is lifted, its weight is transmitted through the supporting boss 61 to the clamping part 445, and then to the gripper 44 and the connecting shaft 42.

[0050] See Figures 3 to 4 As shown, the mounting base 31 is provided with a positioning pin 36, and the side wall of the floating base 32 is provided with a positioning hole 322. The positioning pin 36 can be inserted into or removed from the positioning hole 322.

[0051] When the locating pin 36 is inserted into the locating hole 322, the floating seat 32 is held at a preset height. At this time, the connecting shaft 42 is in a lower position, and the gripper 44 remains open to prevent the gripper 44 from clamping prematurely.

[0052] In an optional implementation, the positioning pin 36 can be a manually pulled pin, a cylinder-driven pin, or an electromagnetically driven pin. After the positioning pin 36 is removed, it should avoid the vertical movement path of the floating seat 32 to prevent affecting the floating detection of the floating seat 32.

[0053] See Figures 1 to 2 As shown, a positioning support 48 is provided on the balance beam 20. One end of the positioning support 48 is fixed to the balance beam 20, and the other end is provided with a positioning hole. The product fixture 60 is provided with a positioning post 62, which is correspondingly set with the positioning hole.

[0054] With the above structure, the system first completes the positioning by positioning pin 62 and positioning hole, then pulls out positioning pin 36 to release floating seat 32, and finally moves floating seat 32 upward to drive gripper 44 to clamp product fixture 60, which can reduce clamping misalignment and hoisting sway.

[0055] See Figures 1 to 7 As shown, the present invention provides a hoisting control method based on the above-mentioned dual electric hoist hoisting system.

[0056] Before hoisting, the product fixture 60 is placed on the workstation support surface. The positioning pin 36 is inserted into the positioning hole 322 of the floating seat 32, keeping the floating seat 32 at a preset height. At this time, the connecting shaft 42 is in a lower position, and the gripper 44 remains open.

[0057] During alignment, the two electric hoists 10 drive the balance beam 20 to descend, causing the positioning pin 62 on the product fixture 60 to insert into the positioning hole of the positioning support 48. After the positioning pin 62 mates with the positioning hole, the balance beam 20 and the product fixture 60 are positioned, and the clamping part 445 is aligned with the supporting boss 61.

[0058] After positioning is completed, positioning pin 36 exits positioning hole 322, causing floating seat 32 to release from its holding position.

[0059] Subsequently, the control unit controls the two electric hoists 10 to lift synchronously at a preset lifting speed. The floating seat 32 moves upward under the traction of the corresponding electric hoist 10 and first compresses the first elastic element 331. The floating seat 32 drives the connecting shaft 42 to move upward, and the connecting shaft 42 drives the gripper 44 to swing, so that the clamping part 445 enters below the supporting boss 61.

[0060] When the clamping part 445 enters below the supporting boss 61 and abuts against the lower supporting surface 611 to complete the clamping, the initial gap between the second elastic element 332 and the floating seat 32 disappears, and the second elastic element 332 begins to be compressed. Afterwards, the first elastic element 331 and the second elastic element 332 work together to provide support and cushioning.

[0061] During the pre-tensioning and lifting phase, the product fixture 60 has not yet detached from the workstation support surface. The control unit detects the clamping position signals of the two proximity switches 46. If both proximity switches 46 output clamping position signals within the preset clamping confirmation time, it is determined that both clamping components 41 have been clamped in place, and the two electric hoists 10 are allowed to continue lifting at the preset speed, causing the product fixture 60 to detach from the workstation support surface.

[0062] If any proximity switch 46 fails to output a clamping signal within the preset clamping confirmation time, it is determined that the corresponding clamping component 41 has not clamped properly. At this time, the control unit controls the two electric hoists 10 to stop lifting, and if necessary, lowers them to the pre-tightening state at a preset retraction speed, and outputs a clamping abnormality alarm.

[0063] After clamping, the control unit continuously acquires the detection results of the two displacement detection elements 34. The movement of one floating seat 32 is recorded as the first movement amount, and the movement of the other floating seat 32 is recorded as the second movement amount. Both the first and second movement amounts are the current upward movement of the corresponding floating seat 32 relative to the mounting base 31 from its initial position, with the position where the positioning pin 36 is inserted into the positioning hole 322 and the floating seat 32 is held at a preset height as the zero-position reference. Within the effective detection stroke of the elastic support 33, the larger the current upward movement amount, the greater the load on the corresponding side lifting point.

[0064] When the difference between the first and second movement amounts is within the allowable displacement difference threshold, the control unit controls the two electric hoists 10 to lift synchronously at a preset lifting speed.

[0065] When the difference between the first movement and the second movement exceeds the allowable displacement difference threshold, the control unit controls the electric hoist 10 corresponding to the larger movement to pause, and controls the electric hoist 10 corresponding to the smaller movement to continue to lift at the preset lifting speed until the difference between the two movements returns to the allowable range.

[0066] When the product fixture 60 is lifted to the preset safe height and completely detached from the workstation support surface, and the difference between the first and second movement amounts is within the allowable range, the control unit controls the hoisting system to enter a stable suspension state.

[0067] Subsequently, the hoisting system uses the existing horizontal moving mechanism to move the product fixture 60 to the target workstation at a preset transfer speed. During the horizontal transfer, the two clamping components 41 remain in a clamping state, the positioning pin 62 engages with the positioning hole, and the control unit continuously monitors the absolute value of the difference between the first and second movement amounts.

[0068] When the difference between the first and second movement amounts exceeds the allowable displacement difference threshold, the control unit first controls the horizontal movement mechanism to pause operation, allowing the product fixture 60 to enter a relatively stable state. Subsequently, the control unit controls the electric hoist 10 corresponding to the side with the larger movement amount to maintain its current height, and controls the electric hoist 10 corresponding to the side with the smaller movement amount to move upward at a preset fine-tuning speed. During the upward movement, the lifting point on the side with the smaller movement amount rises, gradually bearing more load, and its floating seat movement increases accordingly until the absolute value of the difference between the first and second movement amounts returns to the allowable range.

[0069] Once the absolute value of the difference between the first and second movement amounts returns to the allowable range, the control unit controls the horizontal movement mechanism to continue operating at the preset transfer speed.

[0070] After the product fixture 60 reaches the target workstation, the control unit controls the two electric hoists 10 to descend synchronously at a preset descent speed. During descent, the weight of the product fixture 60 is gradually transferred from the two lifting points to the support surface of the target workstation. The two floating seats 32 gradually return to their original position under the reset action of the elastic support 33. The first and second movement amounts are the current upward movement amounts of the corresponding floating seats 32, and their values ​​gradually decrease as the floating seats 32 return to their original position.

[0071] During the descent, the control unit continuously acquires the first and second movement amounts. When the absolute value of the difference between the first and second movement amounts is within the allowable range, the control unit controls the two electric hoists 10 to descend synchronously at a preset descent speed.

[0072] When the absolute value of the difference between the first and second movement amounts exceeds the allowable displacement difference threshold, it indicates that the unloading on both sides is asynchronous. At this time, the control unit first controls the two electric hoists 10 to pause their descent; then, it controls the electric hoist 10 corresponding to the side with the smaller movement amount to maintain its current height, and controls the electric hoist 10 corresponding to the side with the larger movement amount to descend at a preset fine-tuning descent speed, so that the lifting point on the side with the larger movement amount is gradually unloaded, and the movement of its floating seat 32 is reduced accordingly, until the difference between the two movement amounts returns to the allowable range; then, the two electric hoists 10 resume synchronous descent at the preset descent speed.

[0073] Before the product fixture 60 is stably positioned, the clamping part 445 remains below the supporting boss 61 and continues to support the product fixture 60, preventing the product fixture 60 from being released prematurely.

[0074] Once the product fixture 60 descends to the target workstation support surface and is stably supported, the control unit controls the two electric hoists 10 to continue descending at a preset speed with a small stroke, further reducing the load on both lifting points. As the load on the lifting points decreases, the floating seat 32 gradually descends and resets under the reset action of the first elastic element 331 and the second elastic element 332, driving the connecting shaft 42 downwards.

[0075] When the connecting shaft 42 moves downward, it drives the gripper 44 to swing in the opposite direction, causing the clamping part 445 to gradually move out of the support boss 61. When the movement of both floating seats 32 has decreased to the preset release range, and the difference between the first movement and the second movement is within the allowable range, it is determined that the lifting points on both sides have been unloaded, and the clamping part 445 releases its support from the product fixture 60.

[0076] After the clamping is released, the positioning pin 36 can be inserted into the positioning hole 322 to keep the floating seat 32 at the preset height (i.e., the initial state before hoisting), at which time the gripper 44 remains open. Subsequently, the control unit controls the balance beam 20 to rise, causing the positioning hole of the positioning support 48 to exit the positioning column 62, completing the transfer of the product fixture 60, and preparing for the next hoisting cycle.

[0077] Using the above method, the system first completes the positioning, then releases the floating seat 32, and then clamps the product fixture 60; during the lifting, horizontal transfer and descent process, the system corrects the deviation based on the difference in the movement of the two floating seats 32; the clamping is released only after the product fixture 60 is stably positioned, thereby reducing the risks of clamping misalignment, beam skew, fixture swaying and premature release.

[0078] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A twin electric hoist lifting system, characterised in that: include: Two electric hoists; Balance beam; Two floating detection lifting point modules are spaced apart along the length of the balance lifting beam; each floating detection lifting point module includes a mounting base, a floating seat, and a displacement detection component; the floating seat is assembled inside the mounting base and floats elastically relative to the mounting base, and its upper part is connected to the hook of the corresponding electric hoist; the displacement detection component is used to detect the amount of movement of the floating seat relative to the mounting base; Two clamping components are respectively set for the two floating detection lifting point modules and are respectively connected to the floating seat. They can switch to the clamping state when the floating seat moves upward relative to the mounting seat to clamp both ends of the load. The control unit is connected to the two electric hoists and the two displacement detection devices. The control unit is used to control the two electric hoists to move at a different speed when the absolute value of the difference in the movement of the two floating seats exceeds the allowable displacement difference threshold, until the absolute value of the difference in the movement of the two floating seats falls back to the threshold range, and then the two electric hoists resume moving at a preset speed. The floating detection suspension point module is equipped with a guide structure; the guide structure includes two vertical guide columns and a guide sleeve, with the top plate and bottom plate of the mounting base respectively fixed at both ends of the guide columns, and the guide sleeve fixed in the floating base and slidably fitted onto the guide columns; The floating detection suspension point module is equipped with an elastic support component, which includes a first elastic component and a second elastic component, wherein the stiffness of the second elastic component is greater than that of the first elastic component. The first elastic member has two ends that abut against the top plate of the mounting base and the floating base, respectively; one end of the second elastic member is connected to the top plate, and the other end has an initial gap with the floating base; The floating seat first compresses the first elastic element when it moves upward, and after the initial gap is eliminated, the second elastic element is also compressed.

2. Double electric hoist lifting system according to claim 1, characterized in that: One end of the guide post is provided with a limiting connector that connects to the top plate, and the outer diameter of the limiting connector is larger than the outer diameter of the main body of the guide post.

3. The twin electric hoist lifting system of claim 1, wherein: The displacement detection component includes a displacement sensor and a detection protrusion. The displacement sensor is disposed on the side plate of the mounting base, and the detection protrusion is disposed on the side of the floating base facing the displacement sensor. When the floating base moves relative to the mounting base, the displacement sensor detects the displacement change of the detection protrusion in real time.

4. The twin electric hoist rigging system of claim 1, wherein: Each clamping assembly includes a hinge seat and a gripper; the hinge seat is fixed to the balance beam; the gripper includes a drive arm, a clamping arm, and a hinge between the two, wherein the drive arm and the clamping arm are arranged at an obtuse angle. The hinged part is hinged to the hinged seat; the free end of the clamping arm forms a clamping part; the driving arm is provided with a waist-shaped groove; the floating seat is connected to a connecting shaft, the bottom of the connecting shaft passes through the balance beam and is provided with a rotating shaft, the rotating shaft is installed in the waist-shaped groove and can slide along the groove.

5. A twin electric hoist lifting system according to claim 4, characterised in that: The end of the drive arm forms a trigger part, a bracket is provided below the balance beam, a proximity switch is provided on the bracket, and the proximity switch is electrically connected to the control unit; When the gripper swings to the preset gripping position, the trigger part enters the detection range of the proximity switch, and the proximity switch outputs a gripping position signal to the control unit.

6. The twin electric hoist lifting system of claim 1, wherein: The mounting base is provided with a positioning pin, which can move between a holding position and a releasing position; in the holding position, the positioning pin engages with a positioning hole on the side wall of the floating seat to hold the floating seat at a preset height and to keep the clamping assembly in the open state. In the released position, the positioning pin releases its hold on the floating seat, allowing the floating seat to move upward relative to the mounting base under the lifting load of the electric hoist, thereby driving the clamping assembly to clamp the load.

7. The twin electric hoist lifting system of claim 1, wherein: The balance beam is provided with a positioning support, one end of which is fixedly connected to the balance beam, and the other end is provided with a positioning hole; the load is a product fixture containing a workpiece, and the product fixture is provided with a positioning post, which is inserted into the positioning hole to limit the relative position between the balance beam and the product fixture.

8. A method for controlling the hoisting of dual electric hoists, characterized in that: Using the dual electric hoist lifting system according to any one of claims 1 to 7, the control method includes: The electric hoist is started at a preset speed, pulling the floating seat upward; the rising of the floating seat causes the clamping assembly to clamp the load. During the upward movement of the floating seats, the movement of the two floating seats relative to their respective mounting seats is monitored in real time to obtain the first movement and the second movement. Calculate the absolute value of the difference between the first movement amount and the second movement amount. If the absolute value of the difference exceeds a preset threshold, control the electric hoist corresponding to the side with the larger movement amount to pause, and control the electric hoist corresponding to the side with the smaller movement amount to continue lifting until the absolute value of the difference is within the preset threshold range.

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