A double-drum double-drive protection alarm circuit for a crane

Abstract

The utility model discloses a kind of crane double drum double drive protection alarm circuit, including PLC controller, frequency converter and operating mechanism, frequency converter is equipped with two and respectively frequency conversion control corresponding operating mechanism, PLC controller controls two frequency converter operation;The drum of operating mechanism is equipped with encoder, and encoder feedback signal is given to PLC controller;The output module of PLC controller has contactor K01 and relay K02, the two normally closed contact of contactor K01 respectively correspond to series connection to the power supply circuit of two operating mechanism, and the normally open contact of relay K02 is in series with buzzer;PLC controller calculates the speed difference of the encoder of two operating mechanisms and the actual height difference of two steel wire ropes, and according to the threshold value set control relay on-off function.The utility model has real-time monitoring, audible and visual alarm and emergency shutdown protection function, can effectively prevent the safety accident such as off-load, steel wire rope fracture caused by synchronous out of control, ensure double drum double drive lifting safety.

Description

Technical Field

[0001] This utility model relates to the field of crane control technology, specifically a crane dual-drum dual-drive protection alarm circuit. Background Technology

[0002] In modern industrial production and large-scale engineering construction, cranes, as key equipment for material handling, are widely used in ports, shipbuilding, metallurgy, power and other fields. For large-tonnage or long-span cranes, especially bridge cranes or gantry cranes, in order to ensure the stability and safety of the lifting operation, a double-drum double-drive system is usually adopted. That is, the wire ropes at both ends of the lifting device are controlled by two independent drums and drive mechanisms to achieve synchronous lifting or lowering.

[0003] Currently, large-tonnage bridge cranes adopt a structure with two drums and two drives lifting a single hook. In actual operation, due to factors such as mechanical transmission errors, differences in motor performance, uneven wire rope elongation, load imbalance, or electrical control system failures, deviations in the operating speed of the two drums can easily occur, or cumulative differences in the released length of the wire rope can arise after prolonged operation. If such asynchronous speeds or inconsistent heights are not detected and controlled in time, they can cause minor issues such as lifting equipment tilting and cargo swaying, affecting operational efficiency and positioning accuracy; or more serious issues such as uneven wire rope stress, knotting, breakage, or even the falling of heavy objects, leading to serious safety accidents. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the existing defects and provide a crane dual-drum dual-drive protection alarm circuit with real-time monitoring, audible and visual alarm and emergency stop protection functions. It can effectively prevent safety accidents such as uneven load and wire rope breakage caused by synchronous loss of control, and ensure the safety of dual-drum dual-drive lifting. It can effectively solve the problems in the background technology.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a double-drum, double-drive protection alarm circuit for a crane, comprising a PLC controller, a frequency converter, and a running mechanism. The frequency converter has two components, each controlling a corresponding running mechanism via frequency conversion. The PLC controller controls the operation of the two frequency converters. The drum of the running mechanism is equipped with an encoder to detect its rotational speed, and the encoder feeds back a signal to the PLC controller. The output module of the PLC controller has a contactor K01 and a relay K02. The two normally closed contacts of the contactor K01 are connected in series to the power supply circuits of the two operating mechanisms, respectively, and the normally open contacts of the relay K02 are connected in series to a buzzer. The PLC controller calculates the speed difference between the encoders of the two operating mechanisms and controls the relay K02 to switch on and off according to the set threshold. At the same time, it uses the encoder pulse accumulation to calculate the current number of rotations of the drums of the two operating mechanisms, converts it into the wire rope release length, compares the actual height difference between the two wire ropes in real time, and controls the contactor K01 to switch on and off according to the set threshold.

[0006] Preferably, the encoder is an incremental photoelectric encoder or an absolute encoder, installed on the non-load side shaft of the drum of the running mechanism, for real-time acquisition of pulse signals of drum rotation.

[0007] Preferably, the speed difference threshold set in the PLC controller is 3%, and the height difference threshold is 50mm. The thresholds can be configured and adjusted in real time through the human-machine interface.

[0008] Preferably, when the PLC controller determines that the speed difference between the two operating mechanisms exceeds a set threshold, it controls the relay K02 to be energized and triggers the buzzer to emit an audible and visual alarm signal; when the PLC controller determines that the actual height difference between the two wire rope drums exceeds a set threshold, it controls the contactor K01 to be energized and cuts off the main power supply circuit of the two operating mechanisms to achieve emergency shutdown protection.

[0009] Compared with the prior art, the beneficial effects of this utility model are: by monitoring the drum speed of the two operating mechanisms through the encoder, the PLC controller controls the on / off of contactor K01 or K02 according to the speed deviation threshold and the height difference threshold, and provides speed difference warning and height difference emergency stop, which has dual functions of warning and protection. It can effectively prevent safety accidents such as uneven load and wire rope breakage caused by synchronous loss of control, and ensure the safety of double drum double drive lifting. Attached Figure Description

[0010] Figure 1 This is a circuit diagram of the present invention; Figure 2 This is a schematic diagram of the alarm circuit of this utility model.

[0011] In the diagram: 1 PLC controller, 2 encoder, 3 frequency converter, 4 running mechanism, 5 buzzer. Detailed Implementation

[0012] The present invention can be explained in detail through the following embodiments. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention. In the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "front", "rear", "left", "right" indicating the orientation or positional relationship, they are only corresponding to the drawings of this application for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation.

[0013] Please see Figure 1-2 This utility model provides a technical solution: a double-drum dual-drive protection alarm circuit for a crane, including a PLC controller 1, a frequency converter 3, and a running mechanism 4. The frequency converter 3 is provided with two frequency converters, each controlling the corresponding running mechanism 4. The PLC controller 1 controls the operation of the two frequency converters 3. The drum of the running mechanism 4 is provided with an encoder 2 to detect its rotation speed. The encoder 2 feeds back a signal to the PLC controller 1. The output module of PLC controller 1 includes contactor K01 and relay K02. The two normally closed contacts of contactor K01 are connected in series to the power supply circuits of the two operating mechanisms 4 respectively, and the normally open contacts of relay K02 are connected in series to buzzer 5. PLC controller 1 calculates the speed difference between the encoders 2 of the two operating mechanisms 4 and controls the relay K02 to open and close according to the set threshold. At the same time, it uses the pulse accumulation of encoder 2 to calculate the current number of rotations of the drums of the two operating mechanisms 4, converts it into the wire rope release length, compares the actual height difference between the two wire ropes in real time, and controls the contactor K01 to open and close according to the set threshold. Furthermore, encoder 2 is an incremental photoelectric encoder or an absolute encoder, which is installed on the non-load side end shaft of the drum of the running mechanism 4 to collect the pulse signal of the drum rotation in real time. Specifically, the speed difference threshold set in PLC controller 1 is 3%, and the height difference threshold is 50mm. The thresholds can be configured and adjusted in real time through the human-machine interface. It should be noted that when the PLC controller 1 determines that the speed difference between the two operating mechanisms 4 exceeds the set threshold, the control relay K02 is energized, the normally open contact of the relay K02 closes, and the buzzer 5 is triggered to emit an audible and visual alarm signal; when the PLC controller 1 determines that the actual height difference between the two drum wire ropes exceeds the set threshold, the control contactor K01 is energized, the two normally closed contacts of the contactor K01 open, and the main power supply circuit of the two operating mechanisms 4 is cut off, realizing emergency stop protection.

[0014] The parts of this utility model not described in detail are prior art. It is obvious to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments, and that this utility model can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and are intended to include all changes that fall within the meaning and scope of equivalents in the content of this utility model.

Claims

1. A double-drum, double-drive protection alarm circuit for a crane, comprising a PLC controller (1), a frequency converter (3), and a running mechanism (4), characterized in that: The frequency converter (3) is equipped with two operating mechanisms (4) that are respectively frequency-controlled. The PLC controller (1) controls the operation of the two frequency converters (3). The drum of the operating mechanism (4) is equipped with an encoder (2) to detect its rotation speed. The encoder (2) feeds back a signal to the PLC controller (1). The output module of the PLC controller (1) includes a contactor K01 and a relay K02. The two normally closed contacts of the contactor K01 are connected in series to the power supply circuits of the two operating mechanisms (4), and the normally open contacts of the relay K02 are connected in series to a buzzer (5). The PLC controller (1) calculates the speed difference between the encoders (2) of the two operating mechanisms (4) and controls the relay K02 to open and close according to the set threshold. At the same time, it uses the pulse accumulation of the encoder (2) to calculate the current number of rotations of the drums of the two operating mechanisms (4), converts it into the wire rope release length, compares the actual height difference between the two wire ropes in real time, and controls the contactor K01 to open and close according to the set threshold.

2. The crane dual-drum dual-drive protection alarm circuit according to claim 1, characterized in that: The encoder (2) is an incremental photoelectric encoder or an absolute encoder, which is installed on the non-load side shaft of the drum of the running mechanism (4) and is used to collect the pulse signal of the drum rotation in real time.

3. The crane dual-drum dual-drive protection alarm circuit according to claim 1, characterized in that: The speed difference threshold set in the PLC controller (1) is 3%, and the height difference threshold is 50mm. The thresholds can be configured and adjusted in real time through the human-machine interface.

4. The crane dual-drum dual-drive protection alarm circuit according to claim 1, characterized in that: When the PLC controller (1) determines that the speed difference between the two operating mechanisms (4) exceeds the set threshold, it controls the relay K02 to be energized and triggers the buzzer (5) to issue an audible and visual alarm signal; when the PLC controller (1) determines that the actual height difference between the two drum wire ropes exceeds the set threshold, it controls the contactor K01 to be energized and cuts off the main power supply circuit of the two operating mechanisms (4) to realize emergency shutdown protection.

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