Traveling crane lifting limiting device and method
By using a crane lifting limit device to monitor the status of the transmission gear shaft in real time and combining it with foot pedal control, the problem of the crane lifting action being disconnected from the transmission gear shaft is solved, thus achieving safe linkage and efficient protection of the equipment.
Patent Information
- Application Number
- CN202511105290.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-07
- Publication Date
- 2025-11-14
AI Technical Summary
In existing technologies, the lifting and lowering actions of the crane cannot be linked with the transmission gear shaft, leading to equipment damage and safety hazards.
The system employs a crane lifting limit device, which uses a position detection unit to monitor the extension and retraction status of the transmission gear shaft in real time, generates an electrical signal, and combines it with the signal from the foot pedal control unit to achieve precise linkage between the crane lifting action and the transmission gear shaft. This includes a position limiting unit and a safety monitoring mechanism.
It achieves precise linkage between the crane lifting action and the transmission gear shaft, avoiding equipment collision damage, improving equipment reliability and safety, and reducing failure rate and maintenance costs.
Smart Images
Figure CN120945704A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of papermaking technology, and in particular to a crane lifting limit device and method. Background Technology
[0002] In the papermaking industry, large paper machines produce master rolls with wide widths and heavy weights, including the raw paper and rollers. These large master rolls require a rewinding process to cut them into smaller rolls with wider widths and diameters for subsequent processing. During rewinding, a crane is used to lift the large master rolls to the rewinding position on the unwinding rack. The large master rolls are driven by a transmission gear shaft of a drive motor, which is retractable. However, the position of the large master rolls on the unwinding rack is fixed. If the transmission gear shaft does not retract properly when lowering the large master rolls, the descent of the large master rolls will directly crush the gear shaft and the transmission reduction gearbox, causing equipment damage.
[0003] Currently, the industry standard practice involves an operator using an overhead crane to lift the large master roll to the corresponding position on the unloading rack. The crane then lowers to lower the master roll, which is subsequently secured by a hydraulic locking device. A drive gear shaft extends and engages with the teeth on the end face of the master roll roller to provide driving force. However, in this method, the movements of the overhead crane and the drive motor gears are completely independent, lacking a linkage mechanism. If the drive gear shaft fails to retract in time, the large master roll, due to its own weight, will directly impact the gear shaft and gearbox as it descends, causing equipment damage. Furthermore, this process relies entirely on manual observation and operation, posing safety hazards and operational risks.
[0004] Therefore, how to solve the problem that the lifting action of the crane and the transmission gear shaft cannot be linked in the existing technology is one of the important problems that urgently need to be solved in this field. Summary of the Invention
[0005] In view of this, the present disclosure provides a crane lifting limit device and method to solve the problem in the prior art that the crane lifting action and the transmission gear shaft cannot be linked.
[0006] According to one aspect of this disclosure, a crane lifting limit device is provided for controlling the lifting of a crane during rewinding operations to protect transmission equipment. The crane lifting limit device includes:
[0007] The position detection unit is located on the extension and retraction path of the transmission gear shaft and is used to detect the extension and retraction state of the transmission gear shaft. When the transmission gear shaft is detected to be in the retracted state, a first signal is generated, and when the transmission gear shaft is detected to be in the extended state, a second signal is generated.
[0008] The foot pedal control unit outputs a third signal when the foot pedal structure of the foot pedal control unit is operated;
[0009] The vehicle control unit is electrically connected to the position detection unit and the foot pedal control unit. The vehicle control unit is used to receive the first signal and the third signal, and to control the vehicle to perform the descent action.
[0010] When the vehicle control unit receives the first and third signals, it controls the vehicle to perform a lowering action; when the vehicle control unit receives the second signal, it prohibits the vehicle from performing a raising or lowering action; when the vehicle control unit does not receive the third signal, it prohibits the vehicle from performing a lowering action.
[0011] In addition, according to one aspect of the present disclosure, the crane lifting limit device further includes a crane position limiting unit, which is used to limit the working position of the crane and outputs a fourth signal when the crane reaches a preset rewinding working position.
[0012] The vehicle control unit only responds to the first and third signals to control the vehicle's lifting and lowering when it receives the fourth signal.
[0013] According to one aspect of the present disclosure, the vehicle lifting limit device has a foot pedal control unit that is a self-resetting pedal that outputs a third signal only when continuously pressed.
[0014] According to another aspect of this disclosure, a method for limiting the lifting height of a vehicle is also provided, applied to the aforementioned vehicle lifting limit device, the method comprising:
[0015] Control the overhead crane to lift the large master roll to the rewinding position corresponding to the unwinding rack;
[0016] The extension and retraction status of the transmission gear shaft is detected. If the transmission gear shaft is in the extended state, the lifting and lowering operation of the vehicle is prohibited.
[0017] If the transmission gear shaft is in the retracted state, the operator operates the foot pedal device to output a third signal.
[0018] After receiving the first and third signals, the crane control unit controls the crane to perform a descent action until the large master roll is placed on the paper unloading rack;
[0019] After the large mother roll is placed, the operator releases the foot pedal and the crane moves away from the work position.
[0020] According to the crane lifting and limiting method of one aspect of this disclosure, controlling the crane to lift the large master roll to the rewinding operation position corresponding to the unwinding rack includes:
[0021] The crane position restriction program restricts the crane to enter the preset work area, and after entering the work area, the lifting function of the crane hook is locked until the lowering condition is met.
[0022] According to one aspect of the present disclosure, the method for limiting the lifting and lowering of a vehicle includes detecting the extension and retraction state of the transmission gear shaft by means of: detecting the position state of the transmission gear shaft in real time through a position detection unit, and feeding back the state information of the transmission gear shaft to the vehicle control unit.
[0023] According to one aspect of the crane lifting limit method of this disclosure, the operator's operation of the foot pedal device includes:
[0024] The operator must confirm that the transmission gear shaft is in the retracted state before continuously pressing the foot pedal to maintain the output of the third signal.
[0025] According to one aspect of the overhead crane lifting and limiting method of this disclosure, after the large master roll is placed, the operator releases the foot pedal device, and the overhead crane moves away from the work position, which also includes:
[0026] After the crane moves away from the work position, release the foot pedal device;
[0027] Start the roll changing procedure and secure the large master roll using hydraulic clamps;
[0028] The control transmission gear shaft extends and connects to the roller shaft of the large master roll, driving the large master roll to perform rewinding operations.
[0029] According to one aspect of the vehicle lifting limit method of this disclosure, the vehicle lifting limit method also includes a safety monitoring method:
[0030] When the transmission gear shaft is not retracted or the foot pedal is not activated, the audible and visual alarm device is triggered to issue a warning.
[0031] The above-mentioned technical solutions adopted in the embodiments of this disclosure can achieve the following beneficial effects: In the above-mentioned crane lifting limit device, the position detection unit directly monitors the extension and retraction state of the transmission gear shaft and converts it into an electrical signal, enabling the crane control unit to obtain the state information of the transmission gear shaft in real time. This breaks the problem of "disconnection" between the crane lifting control and the gear shaft state in the prior art, and converts the mechanical state of the gear shaft into a "switch signal" that can be recognized by the control unit, providing a prerequisite for linkage control. When the transmission gear shaft is in the extended state, that is, when the position detection unit generates a second signal when the transmission gear shaft is in the extended state, the crane control unit prohibits lifting and lowering actions regardless of whether there is an operation command. This is because when the gear shaft is extended, it may interfere with the crane or other components, and forcibly prohibiting lifting and lowering can avoid collision damage to the transmission equipment. When the transmission gear shaft is in the retracted state, that is, when the position detection unit generates a first signal when it detects that the transmission gear shaft is in the retracted state, the gear shaft does not interfere, which is a safe state. It is only allowed to descend when the foot pedal structure of the foot pedal control unit is operated and outputs a third signal. If there is no third signal output from the foot pedal control unit, descent is prohibited, which can prevent accidental triggering or unnecessary actions. The device captures the state of the transmission gear shaft in real time through the position detection unit, and strictly limits the lifting and lowering actions of the crane to the safe state of the gear shaft retracted through the logic rules of the crane control unit. It directly prohibits the action when the gear shaft is extended, thus realizing the precise linkage between the lifting and lowering of the crane and the state of the transmission gear shaft, and solving the risk of equipment damage caused by the disconnect between the two in the existing technology.
[0032] Building upon this foundation, the position detection unit can detect changes in the gear shaft position within milliseconds and adjust the gantry status in real time via the gantry control unit. This real-time feedback mechanism significantly improves equipment reliability and fault response speed. The independent design of the foot pedal control unit ensures physical isolation between the operator and the gantry. Even if the position detection unit malfunctions, the untriggered state of the foot switch can still prevent gantry movement, forming a "double insurance" mechanism to avoid potential personal injury or equipment damage. The gantry control unit can record the signal status of the position detection unit and the foot pedal control unit, providing data support for equipment maintenance. This effectively solves the problem in existing technologies where the gantry lifting action and the transmission gear shaft cannot be linked. Attached Figure Description
[0033] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0034] Figure 1This is a schematic diagram of the structure of the crane lifting limit device according to an embodiment of the present disclosure;
[0035] Figure 2 This is a flowchart illustrating the crane lifting limit method according to an embodiment of the present disclosure;
[0036] Figure 3 This is a schematic diagram illustrating the process of moving the crane away from the work location according to an embodiment of this disclosure.
[0037] Figure label:
[0038] 101 - Carriage control unit, 102 - Position detection unit, 103 - Foot pedal control unit, 104 - Transmission gear shaft, 105 - Position limiting unit, 106 - Paper ejector. Detailed Implementation
[0039] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.
[0040] It should be understood that the steps described in the method embodiments of this disclosure may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this disclosure is not limited in this respect.
[0041] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below. It should be noted that the concepts of "first", "second", etc., used in this disclosure are only used to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.
[0042] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".
[0043] The names of messages or information exchanged between multiple devices in the embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of such messages or information.
[0044] In the papermaking industry, large paper machines produce master rolls with wide widths and heavy weights, including the raw paper and rollers. These large master rolls require a rewinding process to cut them into smaller rolls with wider widths and diameters for subsequent processing. During rewinding, a crane is used to lift the large master rolls to the rewinding position on the unwinding rack. The large master rolls are driven by a transmission gear shaft of a drive motor, which is retractable. However, the position of the large master rolls on the unwinding rack is fixed. If the transmission gear shaft does not retract properly when lowering the large master rolls, the descent of the large master rolls will directly crush the gear shaft and the transmission reduction gearbox, causing equipment damage.
[0045] Currently, the industry standard practice involves an operator using an overhead crane to lift the large master roll to the corresponding position on the unloading rack. The crane then lowers to lower the master roll, which is subsequently secured by a hydraulic locking device. A drive gear shaft extends and engages with the teeth on the end face of the master roll roller to provide driving force. However, in this method, the movements of the overhead crane and the drive motor gears are completely independent, lacking a linkage mechanism. If the drive gear shaft fails to retract in time, the large master roll, due to its own weight, will directly impact the gear shaft and gearbox as it descends, causing equipment damage. Furthermore, this process relies entirely on manual observation and operation, posing safety hazards and operational risks.
[0046] To address the aforementioned issues, this exemplary embodiment provides a crane lifting limit device and method to solve the problem in the prior art where the crane lifting action and the transmission gear shaft cannot be linked.
[0047] A crane lifting limit device according to an embodiment of the present disclosure will now be described in detail with reference to the accompanying drawings.
[0048] Figure 1 This is a schematic diagram of the structure of the crane lifting limit device according to an embodiment of the present disclosure, as shown below. Figure 1 As shown, the aforementioned crane lifting limit device is used to control the lifting of the crane during rewinding operations to protect the transmission equipment. The position detection unit 102 is located on the extension / retraction path of the transmission gear shaft 104 and is used to detect the extension / retraction state of the transmission gear shaft 104. A first signal is generated when the transmission gear shaft 104 is detected to be in a retracted state, and a second signal is generated when the transmission gear shaft 104 is detected to be in an extended state. A third signal is output when the foot pedal structure of the foot pedal control unit 103 is operated. The crane control unit 101 is electrically connected to both the position detection unit 102 and the foot pedal control unit 103. The crane control unit 101 receives the first and third signals and controls the crane to perform a lowering action. When the crane control unit 101 receives the first and third signals, it controls the crane to perform a lowering action. When the crane control unit 101 receives the second signal, it prohibits the crane from performing lifting / retraction actions. When the crane control unit 101 does not receive the third signal, it prohibits the crane from performing a lowering action.
[0049] In practical applications, such as Figure 1 As shown, the position detection unit 102 directly monitors the extension and retraction state of the transmission gear shaft 104 and converts it into an electrical signal, enabling the vehicle control unit 101 to obtain the status information of the transmission gear shaft 104 in real time. This overcomes the problem of "disconnection" between vehicle lifting control and gear shaft status in existing technologies, converting the mechanical state of the gear shaft into a "switch signal" that can be recognized by the control unit, providing a prerequisite for linkage control. When the transmission gear shaft 104 is in the extended state, that is, when the position detection unit 102 generates the second signal when the transmission gear shaft 104 is in the extended state, the vehicle control unit 101 prohibits lifting and lowering actions regardless of whether there is an operation command. This is because the extended gear shaft may interfere with the vehicle or other components, and forcibly prohibiting lifting and lowering can avoid collision damage to the transmission equipment. When the transmission gear shaft 104 is in the retracted state, that is, when the position detection unit 102 generates the first signal when it detects that the transmission gear shaft 104 is in the retracted state, the gear shaft does not interfere, which is a safe state. Lowering is only allowed when the foot pedal structure of the foot pedal control unit 103 is operated and outputs a third signal. If there is no third signal output from the foot pedal control unit 103, descent is prohibited to prevent accidental triggering or unnecessary actions. After receiving the first and third signals, the crane control unit 101 controls the crane to perform a descent until the large master roll is placed on the paper unloading rack 106. This crane lifting limit device captures the state of the transmission gear shaft 104 in real time through the position detection unit 102, and strictly limits the crane lifting action to the safe state of gear shaft retraction through the logic rules of the crane control unit 101. It directly prohibits action when the gear shaft is extended, thus achieving precise linkage between the crane lifting and the state of the transmission gear shaft 104, solving the risk of equipment damage caused by the disconnection between the two in the prior art.
[0050] Based on this, the position detection unit 102 can detect changes in the gear shaft position within milliseconds and adjust the travel status in real time through the travel control unit 101. This real-time feedback mechanism significantly improves the reliability and fault response speed of the equipment. The independent design of the foot pedal control unit 103 ensures physical isolation between the operator and the travel vehicle. Even if the position detection unit 102 malfunctions, the untriggered state of the foot switch can still prevent the travel vehicle from moving, forming a "double insurance" mechanism to avoid potential personal injury or equipment damage. The travel control unit 101 can record the signal status of the position detection unit 102 and the foot pedal control unit 103, providing data support for equipment maintenance. This effectively solves the problem in the prior art where the travel vehicle lifting action and the transmission gear shaft 104 cannot be linked in state.
[0051] For example, such as Figure 1As shown, the crane lifting limit device also includes a crane position limiting unit 105, which limits the working position of the crane. When the crane reaches the preset rewinding position, it outputs a fourth signal. When the crane control unit 101 receives the fourth signal, it responds to the first and third signals to control the crane lifting.
[0052] In practical applications, such as Figure 1 As shown, when the crane moves to the preset rewinding area, the position detection module generates a fourth signal and transmits it to the crane control unit 101. When the gear shaft is in the retracted state, it indicates that the coupling has disengaged from the paper roll, and the crane is ready to descend. If the gear shaft is in the extended state, the system immediately prohibits the crane movement to prevent mechanical interference. The operator must actively trigger the third signal through the foot pedal control unit 103. The system only allows the crane to perform the descent movement after triple logic verification of the fourth, first, and third signals. If the crane deviates from the preset position during operation, the crane lifting limit device immediately cuts off the lifting control circuit. Regardless of the status of other signals, if the gear shaft fails to retract due to a malfunction, the system remains locked even if the crane position is correct and the foot pedal is triggered.
[0053] As can be seen from the above implementation process, the crane lifting limit device, through the introduction of the position limiting unit 105, achieves a shift from "passive protection" to "active control." It constructs a "zero-error operation" safety barrier, rare in industrial automation scenarios, through three-dimensional signal interlocking. Standardized processes and dynamic responses significantly improve operational efficiency and equipment utilization. Redundant design and environmental adaptability optimization substantially reduce equipment failure rates and maintenance costs. It is particularly suitable for high-end manufacturing fields with extremely high requirements for safety, precision, and reliability.
[0054] For example, such as Figure 1As shown, the foot pedal control unit 103 is a self-resetting pedal, outputting the third signal only when continuously pressed. When the operator releases the pedal, it automatically resets, and the third signal immediately stops outputting. The crane control unit 101 is prohibited from descending when it does not receive the third signal. This means that the crane's descent must rely on the operator's continuous active operation. Releasing the pedal, or actively releasing it when descent is no longer necessary, will immediately stop the crane's descent, avoiding risks such as collisions or damage to the transmission equipment caused by accidental pedal contact, jamming, or continued descent after the operator leaves. Simultaneously, during rewinding operations, the crane's lifting and lowering must be coordinated with the state and working position of the transmission gear shaft 104, requiring high precision. The self-resetting pedal requires the operator to continuously apply force to maintain the third signal output, allowing the operator to control the crane's descent in real time. Pressing the pedal when descent is needed and releasing it when paused provides direct and immediate feedback, avoiding the problem of continuous descent caused by forgetting to reset the pedal, which is a problem with non-self-resetting pedals. This allows for more precise coordination with the rewinding operation rhythm, protecting the transmission equipment and ensuring it operates within a reasonable range.
[0055] Figure 2 This is a flowchart illustrating the crane lifting and limiting method according to an embodiment of the present disclosure, as follows: Figure 2 As shown, the crane lifting limit method is applied to the aforementioned crane lifting limit device, and the crane lifting limit method includes:
[0056] S201: Control the crane to lift the large master roll to the rewinding position corresponding to the unwinding rack.
[0057] S202: Detect the extension / retraction state of the transmission gear shaft. If the transmission gear shaft is in the extended state, the crane is prohibited from performing lifting / lowering operations.
[0058] S203: If the transmission gear shaft is in the retracted state, the operator operates the foot pedal device to output a third signal.
[0059] S204: After receiving the first and third signals, the crane control unit controls the crane to perform a descent action until the large master roll is placed on the paper ejector.
[0060] S205: After the large mother roll is placed, the operator releases the foot pedal and the crane moves away from the work position.
[0061] For example, controlling the crane to lift the large master roll to the rewinding operation position corresponding to the unwinding rack includes limiting the crane to enter the preset operation area through the crane position limiting program, and locking the lifting function of the crane hook after entering the operation area until the lowering condition is met.
[0062] For example, detecting the extension and retraction state of the transmission gear shaft includes detecting the position state of the transmission gear shaft in real time through a position detection unit and feeding back the state information of the transmission gear shaft to the vehicle control unit.
[0063] For example, the operator operating the foot pedal device includes the operator confirming that the transmission gear shaft is in the retracted state and then continuously stepping on the foot pedal device to maintain the output of the third signal.
[0064] For example, Figure 3 This is a schematic diagram illustrating the process of moving the crane away from the work position according to an embodiment of this disclosure, as follows: Figure 3 As shown, after the large master roll is placed, the operator releases the foot pedal, and the crane moves away from the work position, which also includes:
[0065] S301: Release the foot pedal mechanism after the crane moves away from the work position.
[0066] S302: Start the roll changing procedure and fix the large master roll with hydraulic clamps.
[0067] S303: Controls the extension of the transmission gear shaft and its connection with the roller shaft of the large master roll to drive the large master roll to perform rewinding operations.
[0068] For example, the vehicle lifting limit method also includes triggering an audible and visual alarm device to issue a warning when it is detected that the transmission gear shaft has not retracted or the foot pedal device has not been activated.
[0069] In practical applications, when the transmission gear shaft is not retracted or the foot pedal is not activated, it constitutes a scenario where lifting or lowering the crane is prohibited. Triggering an audible and visual alarm in this situation immediately signals to the operator that the current state does not meet safe operating conditions, directly preventing the operator from attempting forced lifting or lowering without noticing the abnormality. This avoids transmission gear shaft collisions, equipment jamming, or structural damage caused by "illegal lifting or lowering," strengthening proactive safety protection. Simultaneously, during rewinding operations, the audible and visual alarm, through targeted prompts for the transmission gear shaft not retracting or the foot pedal not activating, clearly points to missing steps in the operating procedure. If the alarm is triggered by the transmission gear shaft not retracting, the operator will prioritize checking the gear shaft's condition. If the alarm is triggered by the foot pedal not activating, the operator will be reminded to continuously press the foot pedal to meet the requirements. This closed loop from alarm to investigation to correction compels operators to check the equipment status and perform operations according to standardized procedures, reducing non-standard operations caused by negligence or procedural omissions, and improving the standardization of operations. Upgrading passive protection to proactive early warning not only strengthens safety guidance for operators but also improves the reliability of rewinding operations from both process and equipment perspectives.
[0070] The above description is merely an embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features disclosed in this disclosure that have similar functions.
[0071] While specific embodiments of this disclosure have been described in detail by way of example, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.
Claims
1. A crane lifting limit device, used to control the lifting of a crane during rewinding operations to protect the transmission equipment, characterized in that, The crane lifting limit device includes: A position detection unit is located on the extension and retraction path of the transmission gear shaft and is used to detect the extension and retraction state of the transmission gear shaft. When the transmission gear shaft is detected to be in a retracted state, a first signal is generated, and when the transmission gear shaft is detected to be in an extended state, a second signal is generated. A foot pedal control unit that outputs a third signal when the foot pedal structure of the foot pedal control unit is operated; The vehicle control unit is electrically connected to the position detection unit and the foot pedal control unit respectively. The vehicle control unit is used to receive the first signal and the third signal, and to control the vehicle to perform a descent action. The vehicle control unit is used to control the vehicle to perform a lowering action when it receives the first signal and the third signal; the vehicle control unit is used to prohibit the vehicle from performing a lifting action when it receives the second signal; and the vehicle control unit is used to prohibit the vehicle from performing a lowering action when it does not receive the third signal.
2. The crane lifting limit device according to claim 1, characterized in that, The crane lifting limit device also includes a crane position limiting unit, which is used to limit the working position of the crane and outputs a fourth signal when the crane reaches the preset rewinding working position. When the vehicle control unit receives the fourth signal, it responds to the first signal and the third signal to control the vehicle's lifting and lowering.
3. The crane lifting limit device according to claim 1, characterized in that, The foot pedal control unit is a self-resetting pedal that outputs the third signal only when it is continuously pressed.
4. A method for limiting the lifting of a vehicle, applied to the vehicle lifting limit device according to any one of claims 1-3, characterized in that, The method for limiting the lifting height of the vehicle includes: Control the overhead crane to lift the large master roll to the rewinding position corresponding to the unwinding rack; The extension and retraction state of the transmission gear shaft is detected. If the transmission gear shaft is in the extended state, the lifting and lowering operation of the vehicle is prohibited. If the transmission gear shaft is in the retracted state, the operator operates the foot pedal device to make the foot pedal device output a third signal; After receiving the first and third signals, the crane control unit controls the crane to perform a descent action until the large master roll is placed on the paper unloading rack; After the large mother roll is placed, the operator releases the foot pedal device, and the crane moves away from the work position.
5. The crane lifting and limiting method according to claim 4, characterized in that, Controlling the overhead crane to lift the large master roll to the corresponding rewinding position on the unwinding rack includes: The crane position restriction program restricts the crane to enter the preset work area, and after entering the work area, the lifting function of the crane hook is locked until the lowering condition is met.
6. The crane lifting and limiting method according to claim 4, characterized in that, Detecting the extension and retraction state of the transmission gear shaft includes: detecting the position state of the transmission gear shaft in real time through a position detection unit, and feeding back the state information of the transmission gear shaft to the vehicle control unit.
7. The crane lifting and limiting method according to claim 4, characterized in that, The operator operates the foot pedal device including: After confirming that the transmission gear shaft is in the retracted state, the operator must continue to step on the foot pedal to maintain the output of the third signal.
8. The crane lifting and limiting method according to claim 4, characterized in that, After the large mother roll is placed, the operator releases the foot pedal device, and the crane moves away from the work position, which also includes: After the vehicle moves away from the work position, release the foot pedal device; Start the roll changing procedure and secure the large master roll using hydraulic clamps; The transmission gear shaft is controlled to extend and connect with the roller shaft of the large master roll, driving the large master roll to perform rewinding operations.
9. The crane lifting and limiting method according to claim 4, characterized in that, The vehicle lifting limit method also includes a safety monitoring method: When the transmission gear shaft is not retracted or the foot pedal is not activated, the audible and visual alarm device is triggered to issue a warning.