Hydraulic pressure switch type moment limiter for crane

Abstract

The utility model relates to the technical field of hoist, disclose a kind of hydraulic pressure switch type torque limiter for hoist, including first, second pressure switch, first, second normally closed relay, first, second, third normally open relay, time relay, diode module, signal indicating component, proximity switch, solenoid valve and power input interface;When system pressure is normal, or when system pressure is greater than certain proportion of set threshold, or when system pressure exceeds set threshold, by first, second pressure switch, each normally closed relay, the effect of each normally open relay and time relay, respectively control solenoid valve conduction, buzzer flash or long buzz, and proximity switch coil power failure, realize the restriction of crane folding arm torque.The utility model uses the control mode of relay and pressure switch combination to realize centralized control and indication, and it is simple and fast to maintain, and debugging process is easy to operate, can effectively cope with folding arm type hoist industrial field complex working condition.

Description

Technical Field

[0001] This utility model relates to the field of crane technology, specifically to a hydraulic pressure switch torque limiter for cranes. Background Technology

[0002] In the field of crane operations, torque limiters are critical safety devices that prevent overloading and ensure the safety of equipment and personnel. Currently, the mainstream technical solution for torque limiters applied to articulated boom cranes is the electronic torque limiter. These systems typically include angle sensors, length sensors, pressure sensors, or tension sensors to collect parameters such as boom angle, boom extension length, and lifting load or hydraulic system pressure in real time. The collected signals are transmitted to a core electronic controller, such as a PLC or dedicated control module, for processing and calculation to derive the actual lifting torque value, which is then compared with a preset safe torque curve. Once overload or torque approaching the critical value is detected, the controller will issue an audible and visual alarm or cut off dangerous actions.

[0003] However, this controller-based electronic torque limiter has the following significant problems in practical applications: High system complexity and cost: It requires the deployment of multiple sensors and a core controller, resulting in a complex system structure and numerous components, leading to relatively high initial purchase and subsequent maintenance costs; Cumbersome installation and debugging: The installation, positioning, and wiring of multiple sensors, as well as the parameter setting and calibration of the controller, are usually complex and time-consuming, requiring professional technicians and resulting in long debugging cycles; High maintenance dependence and difficulty: The stable operation of the system is highly dependent on the normal operation of the controller. As the core processing unit, a hardware or software failure in the controller may cause the entire torque limiting function to fail. In addition, diagnosing and repairing controller or sensor faults usually requires professional knowledge and equipment, resulting in slow on-site maintenance response and affecting equipment availability. Environmental adaptability challenges: In the complex and harsh industrial environments commonly encountered by cranes, such as high temperature, high humidity, high dust, and strong electromagnetic interference, the long-term stability and reliability of electronic controllers and precision sensors may be affected, posing potential risks of false alarms or failures; Complex calibration process: Calibration of electronic systems often requires connection to dedicated calibration equipment and relies on complex parameter adjustments by the controller program, making the process neither intuitive nor convenient; Insufficient intuitiveness of operating status: Although alarms can be triggered, the intuitive indication of the system status may not be clear or direct enough, relying on the controller interface display.

[0004] These shortcomings affect the ease of use, maintenance efficiency, long-term reliability, and operating costs of torque limiters on articulated boom cranes, especially in situations requiring high reliability and rapid maintenance response. Utility Model Content

[0005] The technical problem this invention aims to solve is to address the shortcomings of existing technologies by providing a hydraulic pressure switch-type torque limiter for cranes. This limiter includes an electrical control circuit and system, and through a dual hydraulic pressure switch structure design, it enables the monitoring and calibration of hydraulic pressure in articulated boom cranes, improving operational convenience and safety. This effectively solves the problems in the background technology.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a hydraulic pressure switch type torque limiter for cranes, comprising a first pressure switch, a second pressure switch, a first normally closed relay, a second normally closed relay, a first normally open relay, a second normally open relay, a third normally open relay, a time relay, a diode module, a signal indicating component, a proximity switch, a solenoid valve, and a power input interface; The first pressure switch is electrically connected to the first normally closed relay, and the second pressure switch is electrically connected to the second normally closed relay; the first normally open relay is electrically connected to the first normally closed relay, the second normally open relay is electrically connected to the first normally closed relay, and the third normally open relay is electrically connected to the second normally closed relay. The first normally open relay is connected to the solenoid valve and also to the signal indicator component; the second normally open relay is connected to the time relay, then to the diode module, then to the signal indicator component, and the second normally open relay is also connected to the proximity switch; the third normally open relay is connected to the signal indicator component.

[0007] The pressure signals connected to the first pressure switch and the second pressure switch come from the rodless chamber of a luffing cylinder of the crane. The first pressure switch and the second pressure switch are set with different starting pressures, and the starting pressure of the second pressure switch is higher than that of the first pressure switch.

[0008] The diode module is connected in parallel with the first normally open relay, the second normally open relay, and the third normally open relay. It plays a role in rectification, protection, or signal processing in the circuit, preventing reverse current flow and ensuring the normal operation of the circuit.

[0009] The proximity switch is used to detect the mechanical position status of the crane's folding arm.

[0010] The signal indicator component includes a green light, a yellow light, a red light, and a buzzer, used to indicate different working states or fault conditions.

[0011] After the time relay coil is energized, its contacts activate after a set time delay to achieve time control.

[0012] When the system pressure is normal and less than a certain percentage of the set threshold, the normally closed contact of the second pressure switch is closed, the circuit remains conductive, the first pressure switch receives power normally, the first normally open relay is energized, its normally open contact closes, the green light of the signal indicator component lights up, and the solenoid valve is activated. When the system pressure is normal and does not exceed the set threshold, but exceeds the set threshold by a certain percentage, the second normally open relay is energized, its normally open contact closes, and the yellow light of the signal indicator component lights up; at this time, the buzzer flashing function is realized through the action of the time relay. When the system pressure is abnormal and exceeds the set threshold, the normally closed contact of the second pressure switch opens. At this time, the normally open relay is energized, and its normally open contact closes. Current flows through the diode module, causing the red light on the signal indicator to illuminate, and the buzzer to sound continuously. Simultaneously, the proximity switch coil is de-energized.

[0013] This utility model also provides the electrical control circuit for the hydraulic pressure switch torque limiter for cranes, as detailed below: The control circuit of the hydraulic pressure switch torque limiter for cranes includes a first pressure switch, a second pressure switch, a first normally closed relay, a second normally closed relay, a first normally open relay, a second normally open relay, a third normally open relay, a time relay, a diode module, a signal indicator component, a proximity switch, a solenoid valve, and a power input interface. The first pressure switch is a normally open pressure switch, electrically connected to terminals 1 and 3 of the first normally closed relay; the second pressure switch is a normally open pressure switch, electrically connected to terminals 1 and 3 of the second normally closed relay; one end of the coil of the first normally open relay is connected to terminal 3 of the first normally closed relay, and the other end is connected to the power input interface, and its normally open contact is connected to the green light of the signal indicator component; one end of the coil of the second normally open relay is connected to terminal 2 of the first normally closed relay, and the other end is connected to the power input interface, and its normally open contact is connected to the yellow light of the signal indicator component, and also connected to one end of the coil of the time relay; the other end of the coil of the time relay is grounded, and its normally closed contact is connected to the diode module, and then connected to the buzzer of the signal indicator component; one end of the coil of the third normally open relay is connected to terminal 2 of the second normally closed relay, and the other end is connected to the power input interface, and its normally open contact is connected to the red light of the signal indicator component, and also connected to the diode module, and then connected to the buzzer of the signal indicator component.

[0014] Working principle of this utility model: When the system pressure is normal and less than a certain percentage of the set threshold, the normally closed contact of the second pressure switch is closed, the circuit remains conductive, and no alarm signal is issued. At this time, the first pressure switch can receive power normally, the first normally open relay is energized, its normally open contact closes, driving the green light to illuminate as an indication signal for normal equipment operation, and the solenoid valve is activated.

[0015] When the system pressure is normal and does not exceed the set threshold, but exceeds the set threshold by a certain percentage, the second normally open relay is energized, its normally open contact closes, and the yellow light illuminates, indicating that the system is in a low-load state. At this time, the buzzer flashing function is achieved through the action of the time relay.

[0016] When the system pressure becomes abnormal and exceeds the set threshold, the normally closed contact of the second pressure switch opens. At this time, the normally open relay is energized, and its normally open contact closes. Current flows through the diode, illuminating the red light, and simultaneously, the buzzer sounds continuously, alerting the operator that the system has experienced an abnormal pressure situation and requires immediate inspection and handling. Simultaneously, the proximity switch coil is de-energized.

[0017] Compared with existing technologies, the advantages of this hydraulic pressure switch torque limiter for cranes are: 1. By adopting the above technical solution, the control circuit can realize centralized control and indication, improve the automation and safety of operation, and facilitate operators to understand the working status of the equipment in a timely manner; through the pressure monitoring and signal light alarm system, the hydraulic system status can be monitored in real time, and alarm prompts will be given when abnormalities occur, effectively preventing equipment damage and operational accidents, and ensuring the safety of personnel and equipment.

[0018] 2. The technical solution provided by this utility model adopts a control method that combines relays and pressure switches. It is a pure electrical logic without a controller. Compared with the traditional control method, it is simple and quick to maintain, easy to operate during the debugging process, and greatly improves the convenience of use. It has a long service life, higher stability and reliability, and can effectively cope with the complex working conditions in industrial sites. It is suitable for articulated boom cranes. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a circuit diagram of an embodiment of the present invention; Figure 3 for Figure 2 Enlarged view of the left half; Figure 4 for Figure 2 Enlarged view of the right half. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Example 1: As Figure 1 As shown, the hydraulic pressure switch type torque limiter for cranes provided by this utility model includes a first pressure switch, a second pressure switch, a first normally closed relay, a second normally closed relay, a first normally open relay, a second normally open relay, a third normally open relay, a time relay, a diode module, a signal indicator component, a proximity switch, a solenoid valve, and a power input interface. The first pressure switch is electrically connected to the first normally closed relay, and the second pressure switch is electrically connected to the second normally closed relay; the first normally open relay is electrically connected to the first normally closed relay, the second normally open relay is electrically connected to the first normally closed relay, and the third normally open relay is electrically connected to the second normally closed relay. The first normally open relay is connected to the solenoid valve and also to the signal indicator component; the second normally open relay is connected to the time relay, then to the diode module, then to the signal indicator component, and the second normally open relay is also connected to the proximity switch; the third normally open relay is connected to the signal indicator component.

[0022] The pressure signals connected to the first pressure switch and the second pressure switch come from the rodless chamber of a luffing cylinder of the crane. The first pressure switch and the second pressure switch are set with different starting pressures, and the starting pressure of the second pressure switch is higher than that of the first pressure switch.

[0023] When the system pressure is normal and less than 80% of the set threshold, the normally closed contact of the second pressure switch is closed, the circuit remains conductive, the first pressure switch receives power normally, the first normally open relay is energized, its normally open contact closes, the green light of the signal indicator unit lights up, and the solenoid valve is activated. When the system pressure is normal and does not exceed the set threshold, but is greater than 80% of the set threshold, the second normally open relay is energized, its normally open contact closes, and the yellow light of the signal indicator component lights up; at this time, the buzzer flashing function is realized through the action of the time relay. When the system pressure is abnormal and exceeds the set threshold, the normally closed contact of the second pressure switch opens. At this time, the normally open relay is energized, and its normally open contact closes. Current flows through the diode module, causing the red light on the signal indicator to illuminate, and the buzzer to sound continuously. Simultaneously, the proximity switch coil is de-energized.

[0024] Example 2: Figure 2-4 As shown, a specific circuit diagram is provided based on Embodiment 1.

[0025] A hydraulic pressure switch type torque limiter for cranes includes a first pressure switch KP1, a second pressure switch KP2, a first normally open relay KA5, a second normally open relay KA6, a third normally open relay KA7, a first normally closed relay K1, a second normally closed relay K2, a diode module DV1, a signal indicator component SL1, a time relay KT4, a proximity switch SQ1, solenoid valves YA1 and YA2, and power input interfaces 0# and 3#.

[0026] Figure 2 In the middle, interface 0 is grounded, and interface 3 is connected to a 24VDC power supply.

[0027] The normally open relay: when the relay coil is not energized, the contacts are open; when the coil is energized, the contacts are closed. The normally closed relay: when the relay coil is not energized, the contacts are closed; when the coil is energized, the contacts are open.

[0028] The first pressure switch KP1 is a normally open pressure switch, electrically connected to terminals 1 and 3 of the first normally closed relay K1; the second pressure switch KP2 is a normally open pressure switch, electrically connected to terminals 1 and 3 of the second normally closed relay K2; the first normally open relay KA5 has one end of its coil connected to terminal 3 of the first normally closed relay K1, and the other end connected to power input interface 3#, with its normally open contact connected to the green light of the signal indicator component SL1; the second normally open relay KA6 has one end of its coil connected to terminal 2 of the first normally closed relay K1, and the other end connected to power input interface 3#. Interface #3 has its normally open contact connected to the yellow light of signal indicator component SL1, and also to one end of the coil of time relay KT4; the other end of the coil of time relay KT4 is grounded, and its normally closed contact is connected to diode module DV1, and then to the buzzer of signal indicator component SL1; the third normally open relay KA7 has one end of its coil connected to the second terminal of the second normally closed relay K2, and the other end connected to power input interface #3, and its normally open contact is connected to the red light of signal indicator component SL1, and also to diode module DV1, and then to the buzzer of signal indicator component SL1.

[0029] Working principle of this utility model: Both KP1 and KP2 are pressure switches, and the pressure signal they receive comes from the rodless chamber of a luffing cylinder on a crane. The trigger pressures set for KP1 and KP2 are different. When the pressure is less than the set value of KP1 and cannot trigger the pressure set by KP1, the normally closed contact conducts, and the green light illuminates. The normally open contact is open, and the common terminal of KP2 is de-energized.

[0030] When the pressure triggers the set pressure of KP1, but is insufficient to trigger the set pressure of KP2, the normally closed contact breaks (green light goes out), and the normally open contact conducts (KP2 is energized). When the normally closed contact of KP2 conducts (yellow light comes on), the normally open contact of KP2 breaks (red light goes out).

[0031] When the pressure triggers the pressure set by KP2, the normally closed contact of KP1 breaks (green light goes out), and the normally open contact of KP1 conducts (KP2 is energized). The normally closed contact of KP2 breaks (yellow light goes out), and the normally open contact of KP2 conducts (red light comes on).

[0032] Specifically, in this embodiment, when the system pressure is normal and less than 80% of the set threshold, the normally closed contact of the second pressure switch KP2 is closed, the circuit remains conductive, and no alarm signal is issued. At this time, the first pressure switch KP1 can receive power normally, the first normally open relay KA5 is energized, its normally open contact closes, driving the green light to illuminate as an indication signal for normal equipment operation, and at the same time, the solenoid valve YA1 is activated.

[0033] When the system pressure is normal and does not exceed the set threshold, but is greater than 80% of the set threshold, the second normally open relay KA6 is energized, its normally open contact closes, and the yellow light illuminates, indicating that the system is in a low-load state. At this time, the buzzer flashing function is achieved through the action of the time relay KA4.

[0034] When the system pressure becomes abnormal and exceeds the set threshold, the normally closed contact of the second pressure switch KP2 opens. At this time, the third normally open relay KA7 is energized, and its normally open contact closes. Current flows through the diode module DV1, illuminating the red light and simultaneously triggering a continuous buzzer, alerting the operator that the system pressure is abnormal and requires immediate inspection and handling. Simultaneously, the coil of proximity switch SQ1 is de-energized. The function of proximity switch SQ1 is to limit the folding height of the crane.

[0035] Figure 2 Line 53 is the signal line for the crane's unloading valve, line 54 is the signal line for the regeneration solenoid valve, line 90 is the signal line for the lighting, and line 95 is the signal line for the emergency stop. Solenoid valve YA1 controls the pressure unloading of the control system and is controlled by the emergency stop switch; solenoid valve YA1 also controls the regeneration valve on the telescopic boom and is controlled by the remote control.

[0036] Example 3: The debugging method of this utility model in application is as follows: The debugging tool is an angle measuring instrument.

[0037] Position of the red and yellow light hydraulic pressure switches: When opening the hydraulic pressure switch box, the hydraulic pressure switch on the left side facing the box is the hydraulic pressure switch calibrated for the red light, and the hydraulic pressure switch on the right side is the hydraulic pressure switch calibrated for the yellow light.

[0038] Adjustment method: Turning the knob of the hydraulic pressure switch clockwise increases the trigger pressure; Turning the knob of the hydraulic pressure switch counterclockwise decreases the trigger pressure; When calibrating the red light, the buzzer sounds continuously; When calibrating the yellow light, the buzzer sounds intermittently.

[0039] Adjustment procedures: Red light calibration: (1) When the first luffing jib is lowered to the lowest point, place an angle measuring instrument on the rotating arm; (2) Raise the first luffing jib from bottom to top until the angle measuring instrument shows 18° to 19°; (3) Use the second luffing jib to lift, and select the maximum lifting weight (100% lifting weight) for lifting at the farthest distance on the luffing table; (4) After lifting the counterweight, fully retract the telescopic boom; (5) Extend the telescopic boom, keep the basic boom parallel to the ground, and slow down the extension speed when the boom is about to be fully extended to ensure the boom does not swing and stabilize the oil cylinder pressure; (6) After the boom is fully extended, when the boom is stable, turn the left knob counterclockwise or clockwise until the buzzer sounds continuously, then the red light can be calibrated; (7) Repeat the full extension and retraction of the boom 3 times, and it is qualified if the red light lights up within 30cm before the boom is fully extended; (8) If the calibration is inaccurate, repeat steps (4)-(7) above until the adjustment is accurate, which means the red light calibration is completed.

[0040] Yellow light calibration: (1) On the basis of completing the red light calibration above, fully retract the telescopic boom; (2) Extend the telescopic boom, when there is still one section of the boom to be fully extended, turn the right knob counterclockwise or clockwise until the buzzer sounds intermittently, then the yellow light can be calibrated; (3) Repeat the full extension and retraction of the boom 3 times, and it is qualified if the yellow light lights up within ±30cm before the last section of the boom is fully extended (for example: for an 8-section boom crane, calibration is performed when the 7th section boom is fully extended, and the telescopic length of the boom allows an error of ±30cm); (4) If the calibration is inaccurate, repeat steps (1)-(3) above.

[0041] Repeat the test of the red and yellow lights 2-3 times. If the red light calibration is inaccurate, re-calibrate it; if the yellow light calibration is inaccurate, re-calibrate it until the adjustment is accurate, which means the yellow light calibration is completed.

[0042] Verification method: After the red and yellow lights are calibrated, at the same angle, re-lift with the second luffing jib, select the working condition at the farthest distance on the luffing table, and lift 80% of the rated load. At this time, when the yellow light turns on under the fully extended boom state and the buzzer sounds intermittently, it is qualified. (For example: if the 100% lifting weight is 10 tons, select 8 tons for verification) After the red and yellow lights are adjusted accurately, at the same angle, re-lift with the second luffing jib, select the 100% lifting weight corresponding to the state where there is still one section of the boom to be fully extended on the luffing table. At this time, when the red light turns on and the buzzer sounds continuously, it is qualified. (For example: if the 100% lifting weight corresponding to the state where there is still one section of the boom to be fully extended on the luffing table is 8 tons, select 8 tons as the lifting weight) Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hydraulic pressure switch type torque limiter for cranes, characterized in that: It includes a first pressure switch, a second pressure switch, a first normally closed relay, a second normally closed relay, a first normally open relay, a second normally open relay, a third normally open relay, a time relay, a diode module, a signal indicating component, a proximity switch, a solenoid valve, and a power input interface; The first pressure switch is electrically connected to the first normally closed relay, and the second pressure switch is electrically connected to the second normally closed relay; the first normally open relay is electrically connected to the first normally closed relay, the second normally open relay is electrically connected to the first normally closed relay, and the third normally open relay is electrically connected to the second normally closed relay. The first normally open relay is connected to the solenoid valve and also to the signal indicator component; the second normally open relay is connected to the time relay, then to the diode module, then to the signal indicator component, and the second normally open relay is also connected to the proximity switch; the third normally open relay is connected to the signal indicator component. The pressure signals connected to the first pressure switch and the second pressure switch come from the rodless chamber of a luffing cylinder of the crane. The first pressure switch and the second pressure switch are set with different starting pressures, and the starting pressure of the second pressure switch is higher than that of the first pressure switch.

2. The hydraulic pressure switch type torque limiter for cranes according to claim 1, characterized in that: The diode module is connected in parallel to the first normally open relay, the second normally open relay, and the third normally open relay.

3. The hydraulic pressure switch type torque limiter for cranes according to claim 1, characterized in that: The proximity switch is used to detect the mechanical position status of the crane's boom.

4. The hydraulic pressure switch type torque limiter for cranes according to claim 1, characterized in that: The signal indicator component includes a green light, a yellow light, a red light, and a buzzer.

5. The hydraulic pressure switch type torque limiter for cranes according to claim 1, characterized in that: When the coil of the time relay is energized, its contacts actuate to achieve time control.

6. The hydraulic pressure switch type torque limiter for cranes according to claim 1, characterized in that: When the system pressure is normal and less than a certain percentage of the set threshold, the normally closed contact of the second pressure switch is closed, the circuit remains conductive, the first pressure switch receives power normally, the first normally open relay is energized, its normally open contact closes, the green light of the signal indicator component lights up, and the solenoid valve is activated. When the system pressure is normal and does not exceed the set threshold, but exceeds the set threshold by a certain percentage, the second normally open relay is energized, its normally open contact closes, and the yellow light of the signal indicator component illuminates; at this time, the buzzer flashing function is realized through the action of the time relay. When the system pressure is abnormal and exceeds the set threshold, the normally closed contact of the second pressure switch opens. At this time, the normally open relay is energized, and its normally open contact closes. Current flows through the diode module, causing the red light of the signal indicator component to light up, and the buzzer to sound continuously. Meanwhile, the proximity switch coil is de-energized.

7. The hydraulic pressure switch type torque limiter for cranes according to claim 1, characterized in that: Its electrical control circuit includes a first pressure switch, a second pressure switch, a first normally closed relay, a second normally closed relay, a first normally open relay, a second normally open relay, a third normally open relay, a time relay, a diode module, a signal indicator component, a proximity switch, a solenoid valve, and a power input interface; the first pressure switch is a normally open pressure switch, electrically connected to the first and third terminals of the first normally closed relay; the second pressure switch is a normally open pressure switch, electrically connected to the first and third terminals of the second normally closed relay; one end of the coil of the first normally open relay is connected to the third terminal of the first normally closed relay, and the other end is connected to the power input interface, and its normally open contact is connected to the... The signal indicator component has a green light; the second normally open relay has one end of its coil connected to the second terminal of the first normally closed relay, and the other end connected to the power input interface. Its normally open contact is connected to the yellow light of the signal indicator component, and also to one end of the coil of the time relay; the other end of the coil of the time relay is grounded, and its normally closed contact is connected to the diode module, and then to the buzzer of the signal indicator component; the third normally open relay has one end of its coil connected to the second terminal of the second normally closed relay, and the other end connected to the power input interface. Its normally open contact is connected to the red light of the signal indicator component, and also to the diode module, and then to the buzzer of the signal indicator component.

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