An automatic control method for slack rope protection of gantry crane hoisting point wire rope

Abstract

An automatic control method for slack rope protection at the lifting point of a gantry crane is disclosed. The gantry crane's hoisting winch connects to an automatic hydraulic grab beam below via a steel wire rope. The automatic hydraulic grab beam can controllably grip or release the gate. A gantry crane controller is provided, and a gantry crane load sensor is installed at the shaft of the hoisting winch. The load sensor detects calibrated weight data of the load being lifted by the gantry crane, with the weight without the automatic hydraulic grab beam set to zero. During the process of controlling the hoisting winch to lower the gate, the gantry crane controller detects the calibrated weight data from the load sensor. When the weight data is less than or equal to zero, it serves as the activation point for slack rope protection. By adding a short slack rope protection program to the existing control program, equipment damage accidents caused by excessive slack rope due to human negligence can be effectively avoided. The slack rope protection program does not affect the original protection functions of the lifting equipment, and the program is simple, the protection function is easy to implement, and it has strong versatility.

Description

Technical Field

[0001] This invention relates to the field of safety control technology for water turbine gantry cranes, specifically to an automatic control method for protecting the slack wire rope at the gantry crane hoisting point. Background Technology

[0002] Currently, in hydropower station gate hoisting points, the automatic hydraulic grab beam (hereinafter referred to as the grab beam) connects to the gate. Typically, the gate's water-blocking position is tens of meters underwater. The hoisting operator can determine the grab beam's descent position using gate elevation, grab beam positioning signals, encoder signals, and weight signals. Once it reaches the gate position, the grab beam is threaded through the pin (connecting the gate), thus opening the gate. However, in reality, after the grab beam reaches the gate's working position, the hoisting mechanism can still descend. At this time, the hoisting wire rope is slack. If the operator continues to lower the wire rope due to negligence, the loose wire rope may snag on the grab beam or gate accessories, causing damage to the wire rope during gate lifting and potentially damaging other equipment. Therefore, there is currently a lack of robust slack rope protection measures for the hoisting point wire rope. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an automatic control method for slack rope protection of the gantry crane lifting point wire rope. Based on the existing control program, detection points and detection data of the gantry crane, the control method and the action conditions of the hoisting mechanism are changed. Under certain conditions, the descent action of the gantry crane hoisting mechanism is restricted when the gantry crane wire rope is in a slack state, thereby realizing the slack rope protection of the gantry crane lifting point wire rope. This automatic control method is applicable to all similar gantry crane lifting point wire rope slack rope protection.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] An automatic control method for slack rope protection of a gantry crane lifting point is disclosed. The gantry crane is equipped with a hoisting winch, which is connected to an automatic hydraulic grab beam below via a wire rope. The automatic hydraulic grab beam can controllably grab or release the gate. A gantry crane controller is provided, and a gantry crane load sensor is installed at the shaft of the hoisting winch. The load sensor detects the calibrated weight data of the load being lifted by the gantry crane, with the weight without the automatic hydraulic grab beam set to zero. During the process of controlling the hoisting winch to lower the gate, the gantry crane controller detects the calibrated weight data of the load sensor. When the weight data is less than or equal to zero, it is used as the start time point for activating the slack rope protection.

[0006] The input terminal of the aforementioned gate operator controller is electrically connected to the lifting mechanism handle. When the gate operator controller detects that the lifting mechanism handle is in the lowering position and the weight data after the gate operator load sensor is calibrated is less than or equal to zero, it starts timing. When the timing reaches the set value, the gate operator controller activates and maintains "slack rope protection". At this time, the gate operator controller controls the gate operator to lift the hoist and prevent it from descending.

[0007] During the aforementioned "slack rope protection" period, the "slack rope protection" will be deactivated if the hoisting mechanism handle changes from the descent position to the zero position or the hoisting position.

[0008] During the aforementioned "slack rope protection" period, if the gantry controller detects that the current control mode has been switched to maintenance mode or emergency mode, the "slack rope protection" will be deactivated, and the "slack rope protection" cannot be activated when the control mode is maintenance mode or emergency mode.

[0009] The aforementioned gantry crane controller is communicatively connected to the analog quantity module, and the analog quantity module is electrically connected to the gantry crane load sensor.

[0010] The present invention provides an automatic control method for slack rope protection of the wire rope at the lifting point of a gantry crane. By adding a short slack rope protection program to the existing control program, it can effectively avoid equipment damage accidents caused by excessive slack rope due to human negligence. The slack rope protection program does not affect the original protection function of the lifting equipment, and the program is simple, the protection function is easy to implement, and it has strong versatility. Attached Figure Description

[0011] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0012] Figure 1 This is a schematic diagram of the lifting structure of the gate crane of the hydropower station according to the present invention;

[0013] Figure 2 This is a schematic diagram of the electrical structure of the present invention;

[0014] Figure 3 This is a PLC ladder diagram for the slack rope protection control of the present invention.

[0015] In the diagram: 1. Gantry crane; 2. Wire rope; 3. Automatic hydraulic grab beam; 4. Gate; 5. Lifting mechanism handle; 6. Gantry crane lifting winch; 7. Gantry crane load sensor; 8. Gantry crane controller; 9. Analog module. Detailed Implementation

[0016] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0017] like Figure 1-3As shown, an automatic control method for slack rope protection of a gantry crane lifting point is provided. The gantry crane 1 is equipped with a gantry crane hoisting winch 6, which is connected to an automatic hydraulic grab beam 3 below via a wire rope 2. The automatic hydraulic grab beam 3 can controllably grab or release the gate 4. A gantry crane controller 8 is provided. A gantry crane load sensor 7 is provided at the shaft of the gantry crane hoisting winch 6. The gantry crane load sensor 7 detects the weight data of the gantry crane lifting the load after calibration, and the weight is calibrated to zero without the automatic hydraulic grab beam 3. During the process of controlling the gantry crane hoisting winch 6 to lower the gate 4, the gantry crane controller 8 detects the weight data after calibration by the gantry crane load sensor 7. When the weight data is less than or equal to zero, it is used as the start time point for activating the slack rope protection.

[0018] The input terminal of the aforementioned door operator controller 8 is electrically connected to the lifting mechanism handle 5. When the door operator controller 8 detects that the lifting mechanism handle 5 is in the lowering position and the weight data after the door operator load sensor 7 is calibrated is less than or equal to zero, it starts timing. When the timing reaches the set value, the door operator controller 8 activates and maintains the "slack rope protection". At this time, the door operator controller 8 controls the door operator lifting winch 6 to prevent it from descending.

[0019] During the aforementioned "slack rope protection" period, if the hoisting mechanism handle 5 changes from the descent position to the zero position or the hoisting position, the "slack rope protection" will be released.

[0020] During the aforementioned "slack rope protection" period, if the gantry controller 8 detects that the current control mode has been switched to maintenance mode or emergency mode, the "slack rope protection" will be deactivated, and the "slack rope protection" cannot be activated when the control mode is maintenance mode or emergency mode.

[0021] The aforementioned gantry crane controller 8 is communicatively connected to the analog quantity module 9, and the analog quantity module 9 is electrically connected to the gantry crane load sensor 7.

[0022] The control mode is usually selected by the mode selection knob, which generally includes "Manual JOG", "Automatic AUTO", "Maintenance" and "Emergency EMG" modes. When in "Manual JOG" and "Automatic AUTO" modes, the "slack rope protection" function can be activated normally when the gantry is descending, while the "slack rope protection" function is disabled in "Maintenance" and "Emergency EMG" modes.

[0023] Example:

[0024] like Figure 3As shown in the diagram, "#lower descent" is the input point for detecting the descent motion of the gantry crane's main hoisting mechanism; "#actualvalue tonnage" is the weight data of the gantry crane's hoisted load after calibration based on the gantry crane's load sensor data, with the weight of the empty hook without grab beams calibrated as 0; "#t3" is the on-delay timer; "#remove slack rope protection cut-off" is the input point for slack rope protection cut-off; and "#unload slack rope protection" is the input / output point for slack rope protection.

[0025] Working principle:

[0026] Taking the gate closing operation as an example (the opening operation is similar): When the gate crane's grab beam, connected to the gate, descends along the gate slot to the gate's water-blocking position, the weight of the load lifted by the gate crane gradually decreases from the total weight of the gate and grab beam to zero. Once the weight reaches zero, the gate officially reaches the water-blocking position, at which point the gate crane's grab beam can be retracted. According to the main program segment in the attached diagram, if the main hook continues to descend for three seconds after the weight drops to zero, the slack rope protection is activated, an alarm sounds, and the main hook is forced to stop descending (this step can be implemented by inserting a contact in the original program segment of the gate crane), thereby protecting the steel wire rope of the gate crane's lifting point.

[0027] When the hoisting mechanism handle is returned to the zero position or the hoisting direction is changed, the "#lower descent" contact resets, and the slack rope protection is automatically released. In the gantry crane beam maintenance mode or other special working conditions, the slack rope protection can be manually removed by using "#remove slack rope protection cut-off", thereby releasing the hoisting mechanism descent restriction in the slack rope state.

Claims

1. An automatic control method for slack protection of wire rope at the hoisting point of a gantry crane, wherein the gantry crane (1) is equipped with a gantry crane hoisting winch (6), the gantry crane hoisting winch (6) is connected to an automatic hydraulic grab beam (3) below via a wire rope (2), and the automatic hydraulic grab beam (3) can be controlled to grab or release the gate (4), characterized in that, A gantry crane controller (8) is provided, and a gantry crane load sensor (7) is provided at the shaft of the gantry crane hoisting winch (6). The gantry crane load sensor (7) detects the weight data of the gantry crane after calibration, and sets the weight of the crane without automatic hydraulic grab beam (3) to zero. During the process of controlling the gantry crane hoisting winch (6) to lower the gate (4), the gantry crane controller (8) detects the weight data after calibration of the gantry crane load sensor (7). When the weight data is less than or equal to zero, it is used as the start time point for opening the slack rope protection. The input terminal of the door operator controller (8) is electrically connected to the lifting mechanism handle (5). When the door operator controller (8) detects that the lifting mechanism handle (5) is in the lowering position and detects that the weight data after the door operator load sensor (7) is calibrated is less than or equal to zero, the timing starts. When the timing reaches the set value, the door operator controller (8) activates the "slack rope protection" and maintains it. At this time, the door operator controller (8) controls the door operator lifting winch (6) to prevent it from descending. During the period of "slack rope protection", if the hoisting mechanism handle (5) changes from the descent position to the zero position or the hoisting position, the "slack rope protection" is released.

2. The automatic control method for slack rope protection of the steel wire rope at the gantry crane lifting point according to claim 1, characterized in that, During the "slack rope protection" period, if the gantry controller (8) detects that the current control mode is switched to maintenance mode or emergency mode, the "slack rope protection" is released, and the "slack rope protection" cannot be activated when the control mode is maintenance mode or emergency mode.

3. The automatic control method for slack rope protection of the steel wire rope at the gantry crane lifting point according to claim 2, characterized in that, The gate controller (8) is connected to the analog module (9) for communication, and the analog module (9) is connected to the gate load sensor (7) for electrical connection.

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