Protection system suitable for free face of crane and control method

Abstract

The invention discloses a protection system suitable for a free face of a crane and a control method, and relates to the technical field of metal structure hoists of hydropower stations. The metal protective net retracting and releasing mechanism comprises a first protective net retracting and releasing unit and a second protective net retracting and releasing unit which are symmetrically arranged on the two sides of the hoisting trolley mechanism and are in linkage with the hoisting trolley mechanism, and the first protective net retracting and releasing unit and the second protective net retracting and releasing unit are in a tensioned state; and one ends of the first protective net retracting and releasing unit and the second protective net retracting and releasing unit are fixed at the end parts of the two crane main beams, and the other ends are hung on the hoisting trolley mechanism. The free face protection system is linked with a hoisting trolley mechanism, the free face protection system releases and shrinks the metal protection net by taking the operation data of the hoisting trolley mechanism of the crane as reference, so that the metal protection net is always in a tensioning state, the free face protection system is formed, the normal operation of the crane is not influenced, and the safety of workers is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of metal structure gate hoists for hydropower stations, and more specifically to the technical field of a protection system and control method suitable for an open-air surface of a crane. Background Art

[0002] Cranes are used for lifting heavy objects, usually above the reference plane of the heavy objects. The track of the trolley mechanism is set on the main beam of the crane. To facilitate the operation of the lifting trolley mechanism, one side of the track is the passage area for operators, and the other side is the open area. When operating, inspecting and maintaining the crane, operators need to pass on the main beam of the crane, which poses a risk of falling from a height.

[0003] The current protective measures generally include arranging a safety line near the main beam of the crane, and the operators wearing safety belts, which are hung on the safety ropes as temporary protection when passing. When multiple people are working on the crane at the same time, wearing safety belts is very inconvenient, and the work efficiency is low. In addition, there is a phenomenon that operators do not wear safety belts for convenience, which cannot fundamentally solve the protection problem of the crane's open surface.

[0004] When carrying out major repairs on crane equipment, a large amount of maintenance materials are piled on the crane's main beam. If they are not placed properly or maintenance personnel accidentally collide with them, it is very easy for objects to fall from high altitudes, posing a certain safety risk. Summary of the invention

[0005] The purpose of the present invention is to solve the above-mentioned technical problems and provide a protection system and a control method suitable for the free surface of a crane.

[0006] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0007] One aspect of the present invention provides a protection system suitable for the free surface of a crane, the crane comprising two crane main beams and a lifting trolley mechanism slidably arranged between the two crane main beams, an free surface being formed between the two crane main beams, the protection system comprising a metal protection net retracting and extending mechanism arranged on the free surface, the metal protection net retracting and extending mechanism comprising a first protection net retracting and extending unit and a second protection net retracting and extending unit symmetrically arranged on both sides of the lifting trolley mechanism and linked to the lifting trolley mechanism, the first protection net retracting and extending unit and the second protection net retracting and extending unit being in a tensioned state; one end of the first protection net retracting and extending unit and the second protection net retracting and extending unit are fixed to the ends of the two crane main beams, and the other end is hung on the lifting trolley mechanism.

[0008] Specifically, this plan sets up a metal protective net on the free surface between the main beams of the crane and establishes an free surface protection system. Its control system is linked with the lifting trolley mechanism. With the operating data of the lifting trolley mechanism of the crane as a reference, the free surface protection system releases and contracts the metal protective net so that the metal protective net is always in a tensioned state, forming an free surface protection system without affecting the normal operation of the crane, thereby ensuring the safety of people passing through the main beams of the crane.

[0009] In one embodiment, the first protection net retracting and extending unit and the second protection net retracting and extending unit have the same structure.

[0010] In one embodiment, the first protective net retracting and releasing unit and the second protective net retracting and releasing unit both include a storage reel, a protective net and a reel motor. The storage reel is installed between the ends of two crane main beams. The width of the protective net is adapted to the width of the air-facing surface. The fixed end of the protective net is wound around the storage reel assembly, and the movable end of the protective net is hung on the lifting trolley mechanism.

[0011] In one embodiment, a hooking / unhooking device is provided at both ends of the bottom of the lifting trolley mechanism, and one end of the protective net is connected to the hooking / unhooking device.

[0012] Specifically, a hanging / unhooking device for the protective net is provided at the bottom of the lifting trolley mechanism, which facilitates the quick connection of the protective net with the lifting trolley mechanism; when the air surface protection system fails or needs to be shut down, it can be quickly detached from the lifting trolley mechanism by operating the hanging / unhooking device.

[0013] In one embodiment, position detection devices are installed at the front section of the metal protective net and the bottom of the lifting trolley mechanism for real-time monitoring of the synchronization between the metal protective net and the lifting trolley mechanism. Each position detection device is electrically connected to the crane PLC controller.

[0014] Specifically, the position detection device is a speed synchronization monitoring module. The position detection device is installed at a suitable position at the front end of the metal protective net and the bottom of the lifting trolley mechanism to monitor the synchronization of the metal protective net and the lifting trolley mechanism in real time.

[0015] In one embodiment, the hanging / unhooking device includes an operating rod, net hooks arranged at equal intervals on the operating rod, and fixed bases arranged at both ends of the operating rod, the two fixed bases are fixed on the base of the lifting trolley mechanism, and the position detection device is arranged on one of the fixed bases.

[0016] In one embodiment, one end of the storage drum is connected to the output shaft of the drum motor through a connecting shaft, and the drum motor is electrically connected to the crane PLC controller.

[0017] Specifically, the metal protective net is wrapped around the storage reel, and the other end is connected to the metal protective hanging / unhooking device at the bottom of the lifting trolley mechanism. The storage reel is connected to the three-in-one motor through the connecting shaft. The crane PLC controller controls the rotation of the three-in-one motor to realize the release and retraction of the metal protective net.

[0018] In one embodiment, the protective net is a metal protective net.

[0019] In one embodiment, the metal protective net is woven from crisscross metal wires.

[0020] In one embodiment, the output end of the reel motor is connected to the connecting shaft at one end of the storage reel through a transmission and a torque limiter.

[0021] Another aspect of the present invention provides a control method for a protection system for an open-air surface of a crane, comprising the following steps:

[0022] S1. Determine the operating speed of the air surface protection system based on the operating parameters of the lifting trolley mechanism:

[0023] According to the motor speed of the lifting trolley mechanism and the reduction ratio of the reducer, calculate the rotation speed of the storage drum of the air surface protection system, that is, the release and retraction speed of the metal protection net;

[0024] Assume that the rated speed of the running motor of the lifting trolley mechanism is n1, the reduction gear ratio of the reducer is i1, the wheel diameter of the lifting trolley mechanism is D1, and there is no pulley set, so the pulley set ratio is m1=1, then the rated operating speed of the lifting trolley mechanism is: v1=(π*D1*n1) / (i1*m1).

[0025] Assume that the rated speed of the three-in-one motor of the air surface protection system is n2, the transmission ratio of the reducer is i2, the diameter of the drum is D2, and there is no pulley set, so the pulley set ratio is m2=1, then the rated rotation speed of the drum of the air surface protection system is: v2=(π*D2*n2) / (i2*m2).

[0026] Taking the speed values ​​of the motor of the lifting trolley mechanism at each gear as a reference, according to the proportional relationship between v1 and v2, calculate the speed values ​​of the motor of the air surface protection system at each gear in turn; modify the program of the crane PLC controller to transmit the calculated speed values ​​of each gear to the frequency converter respectively.

[0027] S2. Speed ​​correction of air surface protection system:

[0028] A position detection switch is installed at a suitable position at the front end of the metal protective net and the bottom of the lifting trolley mechanism to monitor the synchronization between the metal protective net and the lifting trolley mechanism in real time, and the operating speed of the air surface protection system is adjusted in time according to the monitoring data.

[0029] During the forward movement of the lifting trolley mechanism, the crane PLC controller reads the deviation value d of the position detection switch in real time. If d is a positive value and d1<d<d2 (taking the zero point of the position detection switch as the reference, d1 is the set maximum allowable deviation distance value, which is adjusted appropriately according to actual needs; d2 is the limit value of the position detection switch), the release speed of the metal protective net increases by 20% (which can be adjusted appropriately according to needs); if d is a negative value and -d2<d<-d1 (taking the zero point of the position detection switch as the reference, d1 is the set maximum allowable deviation distance value, which is adjusted appropriately according to actual needs; d2 is the limit value of the position detection switch), the release speed of the metal protective net decreases by 20% (which can be adjusted appropriately according to needs); within the specified time t, if -d1≤d≤d1 (taking the following limit as the reference, d is a certain distance value, which is adjusted appropriately according to actual needs), the drum rotation returns to normal speed, otherwise the PLC issues an alarm command.

[0030] During the backward movement of the lifting trolley mechanism, the crane PLC controller reads the deviation value d of the position detection switch in real time. If d is a negative value and -d2<d<-d1 (taking the zero point of the position detection switch as the reference, d1 is a certain distance value, which is adjusted appropriately according to actual needs; d2 is the limit value of the position detection switch), the retraction speed of the metal protective net increases by 20% (which can be adjusted appropriately according to needs); if d is a positive value and d1<d<d2 (taking the zero point of the position detection switch as the reference, d1 is a certain distance value, which is adjusted appropriately according to actual needs; d2 is the limit value of the position detection switch), the retraction speed of the metal protective net decreases by 20% (which can be adjusted appropriately according to needs); within the specified time t, if -d1≤d≤d1 (taking the following limit as the reference, d is a certain distance value, which is adjusted appropriately according to actual needs), the drum rotation returns to normal speed, otherwise the crane PLC controller issues an alarm command.

[0031] The beneficial effects of the present invention are as follows:

[0032] 1. The present invention is reasonably designed. A metal protective net is arranged on the free surface between the main beams of the crane to establish a free surface protection system. The control system is linked with the lifting trolley mechanism. With reference to the operation data of the lifting trolley mechanism of the crane, the free surface protection system releases and contracts the metal protective net so that the metal protective net is always in a tensioned state, thereby forming a free surface protection system without affecting the normal operation of the crane and ensuring the safety of people passing through the main beams of the crane.

[0033] 2. The present invention has a simple structure, mature technology, and is easy to manufacture and install.

[0034] 3. This method can be used to protect the free surface of the crane, and essentially solve the safety risks of falling from high altitude and falling objects from high altitude when people pass through and materials are stacked on the crane.

[0035] 4. This method is highly versatile and can be extended to all lifting equipment that requires free surface protection, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 The present invention is a structural schematic diagram of a protection system suitable for a free-surface crane.

[0038] Figure 2 yes Figure 1 A directional view of .

[0039] Figure 3 It is the hardware connection diagram of the crane's free surface protection system.

[0040] Figure 4 It is the process of the trolley mechanism moving forward and the automatic deviation correction procedure of the air surface protection system.

[0041] Figure 5 It is the process of the trolley mechanism retreating and the automatic deviation correction procedure of the air surface protection system. DETAILED DESCRIPTION

[0042] In order to make the technical problems, technical solutions and technical effects of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In addition, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0045] In the description of the embodiments of the present invention, it should be noted that the terms "inside", "outside", "upper", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0046] Example 1

[0047] like Figures 1 to 3 As shown, this embodiment provides a protection system suitable for the free surface of a crane, the crane includes two crane main beams, a lifting trolley mechanism slidably arranged between the two crane main beams, and a free surface is formed between the two crane main beams. The protection system includes a metal protection net retracting and extending mechanism arranged on the free surface, the metal protection net retracting and extending mechanism includes a first protection net retracting and extending unit and a second protection net retracting and extending unit which are symmetrically arranged on both sides of the lifting trolley mechanism and linked to the lifting trolley mechanism, the first protection net retracting and extending unit and the second protection net retracting and extending unit are in a tensioned state; one end of the first protection net retracting and extending unit and the second protection net retracting and extending unit are fixed to the ends of the two crane main beams, and the other end is hung on the lifting trolley mechanism.

[0048] Specifically, this plan sets up a metal protective net on the free surface between the main beams of the crane and establishes an free surface protection system. Its control system is linked with the lifting trolley mechanism. With the operating data of the lifting trolley mechanism of the crane as a reference, the free surface protection system releases and contracts the metal protective net so that the metal protective net is always in a tensioned state, forming an free surface protection system without affecting the normal operation of the crane, thereby ensuring the safety of people passing through the main beams of the crane.

[0049] Example 2

[0050] like Figure 1 to Figure 2 As shown, this embodiment provides a protection system suitable for the free surface of a crane, the crane includes two crane main beams, a lifting trolley mechanism slidably arranged between the two crane main beams, and a free surface is formed between the two crane main beams. The protection system includes a metal protection net retracting and extending mechanism arranged on the free surface, the metal protection net retracting and extending mechanism includes a first protection net retracting and extending unit and a second protection net retracting and extending unit which are symmetrically arranged on both sides of the lifting trolley mechanism and linked to the lifting trolley mechanism, the first protection net retracting and extending unit and the second protection net retracting and extending unit are in a tensioned state; one end of the first protection net retracting and extending unit and the second protection net retracting and extending unit are fixed to the ends of the two crane main beams, and the other end is hung on the lifting trolley mechanism.

[0051] The first protection net retracting and extending unit and the second protection net retracting and extending unit have the same structure.

[0052] The first protective net retracting and releasing unit and the second protective net retracting and releasing unit both include a storage drum, a protective net and a drum motor. The storage drum is installed between the ends of two crane main beams. The width of the protective net is adapted to the width of the free surface. The fixed end of the protective net is wound around the storage drum assembly, and the movable end of the protective net is hung on the lifting trolley mechanism.

[0053] Example 3

[0054] This embodiment is further optimized on the basis of Embodiment 2, specifically:

[0055] Both ends of the bottom of the lifting trolley mechanism are provided with hanging / unhooking devices, and one end of the protective net is connected to the hanging / unhooking device.

[0056] Specifically, a hanging / unhooking device for the protective net is provided at the bottom of the lifting trolley mechanism, which facilitates the quick connection of the protective net with the lifting trolley mechanism; when the air surface protection system fails or needs to be shut down, it can be quickly detached from the lifting trolley mechanism by operating the hanging / unhooking device.

[0057] Example 4

[0058] This embodiment is further optimized on the basis of embodiment 3, specifically:

[0059] Position detection devices are installed at the front section of the metal protective net and the bottom of the lifting trolley mechanism for real-time monitoring of the synchronization between the metal protective net and the lifting trolley mechanism. Each position detection device is electrically connected to the crane PLC controller.

[0060] Specifically, the position detection device is a speed synchronization monitoring module. The position detection device is installed at a suitable position at the front end of the metal protective net and the bottom of the lifting trolley mechanism to monitor the synchronization of the metal protective net and the lifting trolley mechanism in real time.

[0061] Example 5

[0062] This embodiment is further optimized on the basis of embodiment 3, specifically:

[0063] The hooking / unhooking device includes an operating rod, net hooks arranged on the operating rod at equal intervals, and fixed bases arranged at both ends of the operating rod. The two fixed bases are fixed on the base of the lifting trolley mechanism, and the position detection device is arranged on one of the fixed bases.

[0064] One end of the storage drum is connected to the output shaft of the drum motor through a connecting shaft, and the drum motor is electrically connected to the crane PLC controller.

[0065] Specifically, the metal protective net is wrapped around the storage reel, and the other end is connected to the metal protective hanging / unhooking device at the bottom of the lifting trolley mechanism. The storage reel is connected to the three-in-one motor through the connecting shaft. The crane PLC controller controls the rotation of the three-in-one motor to realize the release and retraction of the metal protective net.

[0066] The protective net is a metal protective net. The metal protective net is woven from crisscrossed metal wires. The output end of the reel motor is connected to the connecting shaft at one end of the storage reel through a transmission and a torque limiter.

[0067] Example 6

[0068] This embodiment provides a control aspect of a protection system applicable to an open-air surface of a crane, comprising the following steps:

[0069] S1. Determine the operating speed of the air surface protection system based on the operating parameters of the lifting trolley mechanism:

[0070] According to the motor speed of the lifting trolley mechanism and the reduction ratio of the reducer, calculate the rotation speed of the storage drum of the air surface protection system, that is, the release and retraction speed of the metal protection net;

[0071] Assume that the rated speed of the running motor of the lifting trolley mechanism is n1, the reduction gear ratio of the reducer is i1, the wheel diameter of the lifting trolley mechanism is D1, and there is no pulley set, so the pulley set ratio is m1=1, then the rated operating speed of the lifting trolley mechanism is: v1=(π*D1*n1) / (i1*m1).

[0072] Assume that the rated speed of the three-in-one motor of the air surface protection system is n2, the transmission ratio of the reducer is i2, the diameter of the drum is D2, and there is no pulley set, so the pulley set ratio is m2=1, then the rated rotation speed of the drum of the air surface protection system is: v2=(π*D2*n2) / (i2*m2).

[0073] Taking the speed values ​​of the motor of the lifting trolley mechanism at each gear as a reference, according to the proportional relationship between v1 and v2, calculate the speed values ​​of the motor of the air surface protection system at each gear in turn; modify the program of the crane PLC controller to transmit the calculated speed values ​​of each gear to the frequency converter respectively.

[0074] S2. Speed ​​correction of air surface protection system:

[0075] A position detection switch is installed at a suitable position at the front end of the metal protective net and the bottom of the lifting trolley mechanism to monitor the synchronization between the metal protective net and the lifting trolley mechanism in real time, and the operating speed of the air surface protection system is adjusted in time according to the monitoring data.

[0076] like Figure 4As shown, during the forward movement of the lifting trolley mechanism, the crane PLC controller reads the deviation value d of the position detection switch in real time. If d is a positive value and d1<d<d2 (taking the zero point of the position detection switch as the reference, d1 is the set maximum allowable deviation distance value, which is adjusted appropriately according to actual needs; d2 is the limit value of the position detection switch), the release speed of the metal protection net increases by 20% (which can be adjusted appropriately according to needs); if d is a negative value and -d2<d<-d1 (taking the zero point of the position detection switch as the reference, d1 is the set maximum allowable deviation distance value, which is adjusted appropriately according to actual needs; d2 is the limit value of the position detection switch), the release speed of the metal protection net decreases by 20% (which can be adjusted appropriately according to needs); within the specified time t, if -d1≤d≤d1 (taking the following limit as the reference, d is a certain distance value, which is adjusted appropriately according to actual needs), the drum rotation returns to normal speed, otherwise the PLC issues an alarm command.

[0077] like Figure 5 As shown, during the backward movement of the lifting trolley mechanism, the crane PLC controller reads the deviation value d of the position detection switch in real time. If d is a negative value and -d2<d<-d1 (taking the zero point of the position detection switch as the reference, d1 is a certain distance value, which is adjusted appropriately according to actual needs; d2 is the limit value of the position detection switch), the retraction speed of the metal protection net increases by 20% (which can be adjusted appropriately according to needs); if d is a positive value and d1<d<d2 (taking the zero point of the position detection switch as the reference, d1 is a certain distance value, which is adjusted appropriately according to actual needs; d2 is the limit value of the position detection switch), the retraction speed of the metal protection net decreases by 20% (which can be adjusted appropriately according to needs); within the specified time t, if -d1≤d≤d1 (taking the following limit as the reference, d is a certain distance value, which is adjusted appropriately according to actual needs), the drum rotation returns to normal speed, otherwise the crane PLC controller issues an alarm command.

Claims

1. A protection system for a crane facing an empty surface, the crane comprising two crane main beams and a lifting trolley mechanism slidably arranged between the two crane main beams, the empty surface being formed between the two crane main beams, characterized in that: The protection system includes a metal protection net retracting and releasing mechanism arranged on the air-facing surface, the metal protection net retracting and releasing mechanism includes a first protection net retracting and releasing unit and a second protection net retracting and releasing unit which are symmetrically arranged on both sides of the lifting trolley mechanism and linked with the lifting trolley mechanism, the first protection net retracting and releasing unit and the second protection net retracting and releasing unit are in a tensioned state; one end of the first protection net retracting and releasing unit and the second protection net retracting and releasing unit are fixed to the ends of the two crane main beams, and the other end is hung on the lifting trolley mechanism.

2. A protection system for a crane free-side according to claim 1, characterized in that: The first protection net retracting and extending unit and the second protection net retracting and extending unit have the same structure.

3. A protection system for a crane free-side according to claim 2, characterized in that: The first protective net retracting and releasing unit and the second protective net retracting and releasing unit both include a storage drum, a protective net and a drum motor. The storage drum is installed between the two ends of the crane main beams. The width of the protective net is adapted to the width of the air-facing surface. The fixed end of the protective net is wound around the storage drum assembly, and the movable end of the protective net is hung on the lifting trolley mechanism.

4. A protection system for a crane free-side according to claim 3, characterized in that: Both ends of the bottom of the lifting trolley mechanism are provided with hanging / unhooking devices, and one end of the protective net is connected to the hanging / unhooking device.

5. A protection system for a crane's free surface according to claim 4, characterized in that: Position detection devices are installed at the front section of the metal protective net and the bottom of the lifting trolley mechanism for real-time monitoring of the synchronization between the metal protective net and the lifting trolley mechanism. Each of the position detection devices is electrically connected to the crane PLC controller.

6. A protection system for the free surface of a crane according to claim 5, characterized in that: The hooking / unhooking device includes an operating rod, net hooks arranged on the operating rod at equal intervals, and fixed bases arranged at both ends of the operating rod. The two fixed bases are fixed on the base of the lifting trolley mechanism, and the position detection device is arranged on one of the fixed bases.

7. A protection system for a crane free-side according to claim 3, characterized in that: One end of the storage drum is connected to the output shaft of the drum motor through a connecting shaft, and the drum motor is electrically connected to the crane PLC controller.

8. The protection system for the free surface of a crane according to claim 3, characterized in that: The protective net is a metal protective net, which is woven from crisscrossed metal mesh wires.

9. A protection system for a crane's free surface according to claim 8, characterized in that: The output end of the reel motor is connected to the connecting shaft at one end of the storage reel through a transmission and a torque limiter.

10. A control method for a protection system for a crane facing an open area, using the protection system for a crane facing an open area as claimed in any one of claims 1 to 9, characterized in that: The steps include: S1. Determine the operating speed of the air surface protection system based on the operating parameters of the lifting trolley mechanism: According to the motor speed of the lifting trolley mechanism and the reduction ratio of the reducer, calculate the rotation speed of the storage drum of the air surface protection system, that is, the release and retraction speed of the metal protection net; Assume that the rated speed of the motor of the hoisting trolley mechanism is n1, the speed reduction of the reducer is i1, the wheel diameter of the hoisting trolley mechanism is D1, and there is no pulley block, so the pulley block ratio is m1=1, then the rated operating speed of the hoisting trolley mechanism is: v1=(π*D1*n1) / (i1*m1); Assume that the rated speed of the three-in-one motor of the air protection system is n2, the transmission ratio of the reducer is i2, the diameter of the drum is D2, and there is no pulley group, so the pulley group ratio is m2 = 1, then the rated rotation speed of the drum of the air protection system is: v2 = (π*D2*n2) / (i2*m2); Taking the speed values ​​of each gear of the motor of the lifting trolley mechanism as a reference, according to the proportional relationship between v1 and v2, the speed values ​​of each gear of the motor of the free surface protection system are calculated in sequence; modify the program of the crane PLC controller to transmit the calculated speed values ​​of each gear to the frequency converter respectively; S2. Speed ​​correction of air surface protection system: Install a position detection switch at a suitable position at the front end of the metal protection net and the bottom of the lifting trolley mechanism to monitor the synchronization of the metal protection net and the lifting trolley mechanism in real time, and adjust the operating speed of the air surface protection system in a timely manner according to the monitoring data; During the forward movement of the hoisting trolley mechanism, the crane PLC controller reads the deviation value d of the position detection switch in real time. If d is a positive value and d1<d<d2, the zero point of the position detection switch is used as the reference, and d1 is the set maximum allowable deviation distance value, which is adjusted appropriately according to actual needs; d2 is the limit value of the position detection switch, the release speed of the metal protection net increases by 20% (can be adjusted appropriately according to demand); if d is a negative value, and -d2<d<-d1, the release speed of the metal protection net decreases by 20%; within the specified time t, if -d1≤d≤d1, the reel rotation returns to normal speed, otherwise the PLC issues an alarm command; During the backward movement of the lifting trolley mechanism, the crane PLC controller reads the deviation value d of the position detection switch in real time. If d is a negative value and -d2<d<-d1, the retraction speed of the metal protective net increases by 20%; if d is a positive value and d1<d<d2, the retraction speed of the metal protective net decreases by 20%; within the specified time t, if -d1≤d≤d1, the drum rotation returns to normal speed, otherwise the crane PLC controller issues an alarm command.

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