Lifting system

Abstract

The application provides a lifting system, comprising a lifting platform and a hydraulic driving assembly, the hydraulic driving assembly is connected with the lifting platform, and comprises a hydraulic pump, a reversing valve and a relief valve, the reversing valve comprises a first oil port in communication with an oil outlet of the hydraulic pump; the relief valve has an oil inlet and an oil outlet, the oil inlet is connected to an oil supply pipeline between the hydraulic pump and the first oil port, and the oil outlet is in communication with an oil tank; the relief valve is configured to return the hydraulic oil to the oil tank through the oil outlet when a pressure value of the oil supply pipeline is greater than or equal to a preset pressure value. The application can improve the safety and stability of the lifting system.

Description

Technical Field

[0001] This application relates to the field of lifting equipment technology, and in particular to a lifting system. Background Technology

[0002] Lifting systems are widely used in material handling, equipment installation, and work platform lifting. Among them, the dual-cylinder synchronous lifting system is widely used due to its strong load-bearing capacity and stable operation.

[0003] In related technologies, a lifting system typically includes a lifting platform and a hydraulic drive assembly connected to the lifting platform, which drives the lifting platform to move up and down.

[0004] However, the current hydraulic drive components have poor overload protection capabilities and cannot release high-pressure hydraulic oil in a timely manner, which seriously affects the safety and service life of the lifting system. Utility Model Content

[0005] In view of the above problems, this application provides a lifting system that can release high-pressure hydraulic oil in a timely manner, thereby improving the safety and service life of the lifting system.

[0006] To achieve the above objectives, the embodiments of this application provide the following technical solutions:

[0007] This application provides a lifting system, which includes:

[0008] Lifting platform;

[0009] A hydraulic drive assembly, connected to the lifting platform, includes:

[0010] Hydraulic pump;

[0011] A reversing valve, the reversing valve including a first oil port, the first oil port being connected to the oil outlet of the hydraulic pump;

[0012] An overflow valve has an oil inlet and an oil outlet. The oil inlet is connected to the oil supply pipeline between the hydraulic pump and the first oil port, and the oil outlet is connected to the oil tank. The overflow valve is configured such that when the pressure value of the oil supply pipeline is greater than or equal to a preset pressure value, the hydraulic oil flows back to the oil tank through the oil outlet.

[0013] In one possible implementation, the lifting system further includes a controller and a first pressure sensor disposed on the oil supply line;

[0014] The controller is electrically connected to both the first pressure sensor and the overflow valve. The controller is used to control the oil outlet of the overflow valve to open when the pressure value of the first pressure sensor is greater than or equal to the preset pressure value.

[0015] In one possible implementation, the oil supply line has a rated pressure value, and the ratio of the preset pressure value to the rated pressure value is greater than or equal to 1.1 and less than or equal to 1.3.

[0016] In one possible implementation, the reversing valve further includes a second oil port; the lifting system includes a first drive branch and a second drive branch; the second oil port is connected to the first drive branch and the second drive branch respectively through a diversion pipeline.

[0017] In one possible implementation, the first drive branch and the second drive branch are sequentially provided with a hydraulic lock, a hydraulic cylinder, a speed regulating valve and a speed limiting valve along the hydraulic oil flow direction, and the speed limiting valve is located at the downstream oil return end of the corresponding drive branch; the output ends of the two hydraulic cylinders are connected to the lifting platform.

[0018] In one possible implementation, each of the hydraulic cylinders is provided with a detection element, the detection element and the speed control valve are respectively connected to the controller, the controller being configured to:

[0019] Based on the test values ​​of the two test pieces, determine whether the two hydraulic cylinders are operating synchronously;

[0020] If the two hydraulic cylinders are not operating synchronously, adjust the opening of the two speed control valves.

[0021] In one possible implementation, the detection element includes a stroke sensor or a second pressure sensor.

[0022] In one possible implementation, the lifting system further includes a control box, the controller is disposed in the control box, and the control box has a plurality of control buttons connected to the controller for sending an up command or a down command to the controller.

[0023] The controller is also configured to:

[0024] According to the up command or the down command, the reversing valve is controlled to switch to the up position or the down position.

[0025] In one possible implementation, the reversing valve includes a first electromagnet and a second electromagnet, and the lifting system further includes a first limit switch and a second limit switch.

[0026] The first limit switch is set at the upper limit position of the lifting platform's upward stroke and is electrically connected to the controller, and is used to send an upper limit trigger signal to the controller when triggered;

[0027] The second limit switch is set at the lower limit position of the descent stroke of the lifting platform and is electrically connected to the controller, and is used to send a lower limit trigger signal to the controller when triggered;

[0028] The controller is also configured to:

[0029] When the upper limit trigger signal is received, the first electromagnet is de-energized.

[0030] When the lower limit trigger signal is received, the second electromagnet is de-energized.

[0031] In one possible implementation, a filter is provided on the oil supply line, and the filter is located on the side of the hydraulic pump away from the directional valve.

[0032] In the lifting system provided in this application embodiment, a relief valve is connected in parallel between the hydraulic pump and the first oil port of the reversing valve, and the oil outlet of the relief valve is connected to the oil tank. This allows the hydraulic oil to flow back to the oil tank when the pressure value of the oil supply line is greater than or equal to the preset pressure value, thereby achieving pressure relief protection and preventing damage to the hydraulic components of the hydraulic drive assembly, thus improving the safety and service life of the lifting system.

[0033] In addition to the technical problems solved by the embodiments of this application, the technical features constituting the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions described above, other technical problems that the lifting system provided by the embodiments of this application can solve, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further explained in detail in the specific implementation. Attached Figure Description

[0034] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0035] Figure 1 A schematic diagram of a hydraulic drive assembly provided in an embodiment of this application;

[0036] Figure 2 The control logic diagram of the lifting system provided in the embodiments of this application is shown.

[0037] Figure label:

[0038] 110. Hydraulic pump; 120. Directional control valve; 121. First oil port; 122. Second oil port; 123. Third oil port; 130. Relief valve; 131. Oil inlet; 132. Oil outlet; 140. Oil supply line; 150. Oil tank; 160. Controller; 170. First pressure sensor; 180. Diverter line; 191. Hydraulic lock; 192. Hydraulic cylinder; 193. Speed ​​control valve; 194. Speed ​​limit valve; 195. Detector; 200. Second pressure sensor; 210. First limit switch; 220. Second limit switch; 230. Filter.

[0039] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0040] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0041] As described in the background art, the relevant technology suffers from poor overload protection of hydraulic drive components, failing to release high-pressure hydraulic oil in a timely manner. The reason for this problem is that current methods typically rely on conventional pressure control to regulate the oil circuit status. However, when the lifting platform bears a large load, or operates under conditions such as frequent starts and stops, obstructed movement, or end-of-line impact, the pressure in the oil supply line is prone to abnormally rising. Existing protection methods often fail to effectively release high-pressure hydraulic oil in a timely manner. This not only causes excessive stress on the pipelines, valves, and actuators, but may also lead to accelerated wear of seals, unstable valve operation, or even localized damage, seriously affecting the safety and service life of the lifting system.

[0042] To address the aforementioned technical problems, this application provides a lifting system that connects a relief valve in parallel between the hydraulic pump and the first port of the reversing valve, and connects the outlet of the relief valve to the oil tank. This allows hydraulic oil to flow back to the oil tank when the pressure in the oil supply line is greater than or equal to a preset pressure value, thereby achieving pressure relief protection and preventing damage to the hydraulic components of the hydraulic drive assembly, thus improving the safety and service life of the lifting system.

[0043] To make the above-mentioned objectives, features, and advantages of the embodiments of this application more apparent and understandable, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0044] This application provides a lifting system that is applied to scenarios such as material handling, equipment installation, and work platform lifting to achieve the handling of goods.

[0045] The lifting system includes a lifting platform and a hydraulic drive assembly. The lifting platform is used to support goods, equipment, or other structures. It should be noted that the lifting platform can be any structure found in related technologies; however, this embodiment will not elaborate further.

[0046] The hydraulic drive assembly is connected to the lifting platform to convert hydraulic energy into mechanical lifting force, thereby moving the lifting platform to raise, lower, or lock it. The hydraulic drive assembly is typically located below or to the side of the lifting platform for better connection.

[0047] Please refer to Figure 1 The hydraulic drive components include a hydraulic pump 110, a directional valve 120, and a relief valve 130. The hydraulic pump 110 serves as the power source for the lifting system, outputting hydraulic oil with a certain pressure and flow rate to provide the basic power for the lifting platform's lifting movement. The hydraulic pump 110 typically includes a pump body and a motor, with the motor connected to the pump body. The pump body can be a gear pump, piston pump, or vane pump. In this case, a gear pump is used, with a displacement of 4.2 mL / r and a rated pressure of 21 MPa. The motor power is 0.75 kW. The hydraulic oil is L-HM46 anti-wear hydraulic oil.

[0048] The directional valve 120 has a first oil port 121, which is connected to the oil outlet of the hydraulic pump 110. For example, the oil outlet of the hydraulic pump 110 is connected to the first oil port 121 of the directional valve 120 through the oil supply line 140, so as to receive the hydraulic oil output by the hydraulic pump 110 and introduce the hydraulic oil into the drive branch of the lifting system, thereby facilitating the movement of the lifting platform.

[0049] It should be noted that the connection between the hydraulic pump 110 and the oil supply line 140, and between the first oil port 121 of the directional valve 120 and the oil supply line 140, can be made by threaded joints, flanges or quick-connect couplings, as long as the sealing connection at the connection point can be guaranteed.

[0050] The relief valve 130 has an oil inlet 131 and an oil outlet 132. The oil inlet 131 is connected to the oil supply line 140 between the hydraulic pump 110 and the first oil port 121, and the oil outlet 132 is connected to the oil tank 150, so as to realize the parallel connection of the relief valve 130 and the oil supply line 140. Alternatively, an additional first return oil line can be provided, with one end connected to the oil supply line and the other end connected to the oil tank. The first return oil line can be opened and closed by installing a relief valve on the first return oil line.

[0051] The relief valve 130 is configured such that when the pressure in the oil supply line 140 is greater than or equal to a preset pressure value, the hydraulic oil flows back to the oil tank 150 through the outlet 132. Thus, when the lifting platform bears a large load, its movement is obstructed, or an impact occurs at the end, the pressure in the oil supply line 140 will increase accordingly. At this time, the relief valve 130, connected in parallel between the hydraulic pump 110 and the first oil port 121, responds to the pressure in the oil supply line 140 in real time. For example, when the pressure in the oil supply line 140 reaches the preset pressure value, the relief valve 130 opens the first return oil line, directly returning excess hydraulic oil to the oil tank 150, thereby releasing the high-pressure condition.

[0052] In this embodiment, by arranging the relief valve on the oil supply line between the hydraulic pump outlet and the directional valve inlet, when the lifting system experiences a pressure surge due to overload or mechanical jamming, the abnormally high pressure can be released in time before entering the directional valve 120, thereby limiting the peak pressure borne by the pipeline, valves and actuators, and alleviating the continuous load on the hydraulic pump 110 under high pressure conditions, thus improving the safety of the lifting system.

[0053] It should be noted that the opening of the relief valve 130 needs to be freely set according to its type. For example, when the relief valve 130 is a mechanical relief valve, it can achieve on / off switching by responding to changes in pressure. Alternatively, when the relief valve 130 is an electrically controlled relief valve, it can achieve on / off switching through the cooperation of a controller and a pressure sensor.

[0054] In some embodiments, when the relief valve 130 is a mechanical relief valve, a preset pressure value can be preset for the relief valve 130. In this way, after the pressure reaches the preset pressure value, the relief valve 130 opens the valve core, allowing the high-pressure hydraulic oil to flow back to the oil tank 150 through the oil outlet 132. After the pressure drops, the valve core of the relief valve resets and closes, thereby maintaining the lifting system within the predetermined pressure range.

[0055] During operation, after the hydraulic pump 110 starts, the hydraulic oil enters the directional valve 120 through the oil supply line 140 and is finally delivered to the actuator to drive the lifting platform. When the pressure value of the oil supply line 140 is lower than the preset pressure value, the relief valve 130 is closed, and all the hydraulic oil flows normally along the oil supply line 140.

[0056] When the pressure in the oil supply line 140 rises to or exceeds the preset pressure value due to overload, mechanical jamming, or abnormal switching of the directional valve, the hydraulic pressure exerted by the high-pressure hydraulic oil on the valve core end face of the relief valve 130 overcomes the spring preload, pushing the valve core to open. This allows the high-pressure hydraulic oil to enter the valve body through the inlet of the relief valve 130 and flow back to the oil tank 150 through the outlet 132, thus achieving pressure relief. Once the pressure drops below the preset pressure value, the spring force pushes the valve core to reset and close, maintaining the system within the predetermined pressure range and effectively protecting hydraulic components such as the hydraulic pump, directional valve, pipelines, and seals from high-pressure damage.

[0057] Please combine Figure 1 and Figure 2 In some other embodiments, the overflow valve 130 is an electrically controlled overflow valve. In this case, the lifting system also includes a controller 160 and a first pressure sensor 170 disposed on the oil supply line 140. The controller 160 is electrically connected to both the first pressure sensor 170 and the overflow valve 130. The controller 160 is used to control the oil outlet 132 of the overflow valve 130 to open according to the pressure value of the first pressure sensor 170 being greater than or equal to a preset pressure value.

[0058] The first pressure sensor 170 can detect the pressure value of the oil supply line 140 in real time and transmit the detected pressure signal to the controller 160. The controller 160 compares the received pressure value with a preset pressure value (e.g., 18 MPa). When the controller 160 determines that the pressure value detected by the first pressure sensor 170 is greater than or equal to the preset pressure value, the controller 160 sends an opening control signal to the relief valve 130, controlling the oil outlet of the relief valve 130 to open, allowing the high-pressure hydraulic oil to flow back to the oil tank 150 through the oil outlet 132, thus achieving active pressure relief. When the pressure value detected by the first pressure sensor 170 drops below the preset pressure value, the controller 160 sends a closing control signal to the relief valve 130, controlling the relief valve 130 to close, and the lifting system resumes normal operation.

[0059] With this configuration, the overflow valve 130 is controlled in a closed loop by the first pressure sensor 170 and the controller 160, which enables real-time monitoring and active adjustment of the lifting system pressure. This results in faster response speed, higher control accuracy, and the preset pressure value can be flexibly adjusted according to actual working conditions, further enhancing the intelligence level and load adaptability of the lifting system.

[0060] It should be noted that the preset pressure value can be determined based on the rated working pressure. In some embodiments, the oil supply line 140 has a rated pressure value, and the ratio of the preset pressure value to the rated pressure value is greater than or equal to 1.1 and less than or equal to 1.3. For example, the ratio of the preset pressure value to the rated pressure value is 1.1, 1.2, 1.3, and any two of these values.

[0061] In some possible examples, when the rated pressure of the oil supply line 140 is 16 MPa, the preset pressure value of the relief valve 130 can be set to 18 MPa. By reasonably setting the ratio of the preset pressure value to the rated pressure value, the embodiments of this application can make the overflow protection action both sensitive and stable, ensuring timely pressure relief from overload while reducing false activation, thereby improving the safety and reliability of the lifting system operation.

[0062] In one possible implementation, the directional valve 120 further includes a second port 122; the lifting system includes a first drive branch and a second drive branch; the second port 122 is connected to the first drive branch and the second drive branch respectively via a diversion pipe 180. The second port 122 is a fluid interface on the directional valve 120 for outputting hydraulic oil, capable of guiding hydraulic oil from the hydraulic pump 110 to the diversion pipe 180.

[0063] This allows the first and second drive branches to function as independent hydraulic channels to the two sets of hydraulic actuators. Compared to related technologies where the same drive branch supplies power to both sets of hydraulic actuators, this approach effectively solves the problem of flow distribution imbalance caused by differences in pipeline impedance and uneven load when supplying oil to the two sets of hydraulic actuators. It also effectively eliminates platform imbalance, swaying, and even jamming caused by asynchronous operation of the dual cylinders, significantly improving the synchronization accuracy and operational stability of the dual-cylinder lifting mechanism.

[0064] Meanwhile, the independent oil supply to each branch ensures that the pressure of the two hydraulic actuators does not interfere with each other during operation. When the first drive branch leaks or malfunctions, the second drive branch can still work independently or retract in an emergency, further enhancing the fault tolerance and safety of the lifting system.

[0065] In one possible implementation, the first drive branch and the second drive branch are sequentially provided with a hydraulic lock 191, a hydraulic cylinder 192, a speed control valve 193, and a speed limiter valve 194 along the hydraulic oil flow direction. The hydraulic lock 191 is located between the hydraulic cylinder 192 and the directional valve 120 (i.e., on the upstream side of the corresponding drive branch). The speed control valve 193 and the speed limiter valve 194 are located on the side of the hydraulic cylinder 192 away from the hydraulic lock 191 (i.e., on the downstream side of the corresponding drive branch), so that the speed limiter valve 194 is located at the downstream return oil end of the corresponding drive branch. It should be noted that the directional valve 120 also includes a third oil port 123, which serves as the return oil port of the directional valve. The speed limiter valve 194 is adjacent to the third oil port 123. In addition, the third oil port 123 is also connected to the oil tank 150 through a second return oil line.

[0066] The output ends of two hydraulic cylinders 192 are connected to the lifting platform to drive its normal operation. In this application, the response time of the hydraulic lock 191 is less than or equal to 100ms, and the specifications of the hydraulic cylinders 192 are: cylinder diameter 70mm, stroke 440mm, and the limiting descent speed of the speed limiting valve 194 is less than or equal to 50mm / s; the total emergency stop locking time is less than or equal to 0.5s.

[0067] When the directional valve 120 switches to the lifting position, the hydraulic oil is diverted through the second port 122 and enters the first drive branch and the second drive branch respectively. In each drive branch, the hydraulic oil first reaches the hydraulic lock 191, which opens under pressure, and a supporting force is established in the hydraulic cylinder 192. Then, the hydraulic oil enters the rodless chamber of the hydraulic cylinder 192, pushing the piston rod to extend and driving the lifting platform to rise. The return oil from the rod chamber of the hydraulic cylinder 192 flows out through the speed regulating valve 193 and the speed limiting valve 194 in sequence. The return oil flow can be controlled by adjusting the opening of the speed regulating valve 193, thereby adjusting the lifting speed of the hydraulic cylinder.

[0068] When the directional valve 120 switches to the descent position, the hydraulic oil enters the rod chamber of the hydraulic cylinder through the directional valve 120. The control oil circuit of the hydraulic lock 191 is unloaded, and the hydraulic lock 191 is closed to prevent the hydraulic oil in the rodless chamber from leaking out of control due to pipeline rupture during the descent. At the same time, the return oil from the rodless chamber flows back to the oil tank through the speed regulating valve 193 and the speed limiting valve 194, so as to achieve controllable descent.

[0069] In this embodiment, the hydraulic lock 191 is positioned upstream of the corresponding drive branch, while the speed control valve 193 and the speed limiting valve 194 are positioned downstream. This allows the hydraulic oil to first open the hydraulic lock and establish cylinder support, ensuring stable support before the hydraulic cylinder bears the load. The speed control valve then precisely controls the inflow to the cylinder, preventing shocks and vibrations caused by sudden pressure changes during unlocking. The speed limiting valve 194, located at the downstream return end of the branch, serves as the final safety protection element. If the speed control valve 193 fails or a pipeline rupture causes abnormal return oil speed, the speed limiting valve automatically throttles the flow to limit the descent speed of the hydraulic cylinder, preventing the lifting platform from stalling and falling. This specific series sequence ensures that the hydraulic lock establishes support before fine-tuning the speed, eliminating the starting shock problem caused by the traditional "speed control before unlocking" method.

[0070] Each drive branch is equipped with a hydraulic lock 191. This ensures that even if the pipeline in the first drive branch ruptures, the hydraulic lock 191 in the second drive branch can maintain support, preventing the lifting platform from falling and improving the safety of the lifting system. Furthermore, each hydraulic lock 191 can immediately and physically seal the hydraulic cylinder 192 when the oil supply pressure is lost, achieving zero-second response locking and further enhancing the safety of the lifting system.

[0071] In one possible implementation, a detection element 195 is provided on the hydraulic cylinder 192, and the detection element 195 and the speed control valve 193 are respectively connected to the controller 160, which is configured to:

[0072] Based on the test values ​​of the two test pieces, determine whether the two hydraulic cylinders are operating synchronously;

[0073] If the two hydraulic cylinders are not operating synchronously, adjust the opening of the two speed control valves.

[0074] The detection element 195 can be installed on the hydraulic cylinder body, piston rod, or cylinder end to collect the operating status of the hydraulic cylinder and output a detection signal. For example, the detection element 195 can be a stroke sensor or a second pressure sensor. In some possible examples, the stroke sensor can be a drawstring displacement sensor, which can be installed on the hydraulic cylinder, and the stroke of the drawstring displacement sensor is greater than the stroke of the hydraulic cylinder.

[0075] The detection element 195 can be electrically connected to the controller 160 via a wire connection or bus communication. The controller 160 can determine whether the two hydraulic cylinders 192 are operating synchronously based on the detection values ​​of the two detection elements 195, and then perform the next response operation.

[0076] The above principle is explained below using the detection element 195 as a stroke sensor as an example. For example, the controller 160 receives the stroke values ​​collected by the two detection elements 195 (such as stroke sensors) in real time, and adjusts the opening degree of the two speed control valves 193 according to the collected stroke values.

[0077] In some embodiments, the real-time stroke deviation value of the two hydraulic cylinders can be calculated and compared with a preset allowable deviation range. If the stroke deviation value is within the allowable deviation range, it is determined that the two hydraulic cylinders 192 are operating synchronously, the controller 160 does not output an adjustment signal, and the speed control valve 193 maintains its current opening. If the stroke deviation value exceeds the allowable deviation range, it is determined that the two hydraulic cylinders 192 are not operating synchronously. The controller 160 outputs an opening increase control signal to the speed control valve 193 on the branch with the lagging stroke, according to the deviation direction and deviation amount, so that the oil inlet / return flow of the hydraulic cylinder 192 on that branch increases. After the deviation recovers to the allowable deviation range, the controller 160 controls the speed control valve 193 to return to its initial opening, so that the two hydraulic cylinders 192 re-enter the synchronous operation state.

[0078] In other embodiments, the stroke values ​​of the two hydraulic cylinders can be directly compared. For example, the two hydraulic cylinders can be defined as a first hydraulic cylinder and a second hydraulic cylinder, and the two speed control valves can be defined as a first speed control valve and a second speed control valve. When the stroke value of the first hydraulic cylinder is less than that of the second hydraulic cylinder (i.e., the first hydraulic cylinder's action is lagging), the controller sends an opening increase signal to the first speed control valve on the first drive branch, increasing the opening of the first speed control valve and increasing the flow rate into the first hydraulic cylinder. When the stroke value of the first hydraulic cylinder is close to or equal to that of the second hydraulic cylinder, the controller controls the first speed control valve to return to its initial opening. Similarly, when the action of the second hydraulic cylinder is lagging, the controller controls the second speed control valve to increase its opening accordingly.

[0079] The following embodiments will use the detection element 195 as the second pressure sensor 200 as an example to explain in detail how to achieve synchronous operation of two hydraulic cylinders.

[0080] Two second pressure sensors 200 are respectively installed at the oil inlet of the rodless chamber or the oil outlet of the rod chamber of the two hydraulic cylinders 192. When the two hydraulic cylinders 192 are running synchronously, the pressure values ​​of their corresponding oil ports are basically the same. When the pressure of one hydraulic cylinder 192 is abnormal due to load changes or internal leakage, the controller 160 determines whether the two hydraulic cylinders 192 are running synchronously based on the pressure difference between the two second pressure sensors 200, and adjusts the opening of the speed regulating valve 193 accordingly to compensate, so as to increase the flow rate of the lagging hydraulic cylinder 192 or decrease the flow rate of the leading hydraulic cylinder 192, so as to achieve closed-loop synchronous compensation.

[0081] This embodiment combines the concept of symmetrical design of two drive branches with a synchronous detection and compensation mechanism, which greatly improves the difference between the two hydraulic cylinders from less than or equal to 5% in related technologies (for example, the difference is about 25mm for a 500mm stroke) to less than or equal to 1mm. The synchronization accuracy is improved by more than 25 times, and the synchronization rate reaches 99.8%. This solves the problems of platform tilting, off-center loading jamming and equipment damage caused by the asynchronous operation of the two cylinders under heavy loads, and significantly improves the stability of the lifting platform under heavy load conditions and the load safety.

[0082] In one possible implementation, the lifting system further includes a control box (not shown in the figure), with a controller 160 housed within it. The control box has several control buttons, each connected to the controller 160, used to send raising or lowering commands to the controller 160. For example, the control box serves as a human-machine interface, facilitating operator control of the lifting system's movements and providing protection for the electrical components located within it. It should be noted that the control box can be mounted on the support frame of the lifting platform or on one side of the lifting platform.

[0083] The control buttons are located on the outer surface of the control box and are connected to the controller 160 via wires or a communication interface. The control buttons include at least an up button and a down button. When the operator presses the up button, the control button sends an up command to the controller 160; when the operator presses the down button, the control button sends a down command to the controller 160.

[0084] Controller 160 is also configured to:

[0085] According to the up command or down command, control the reversing valve 120 to switch to the up position or the down position.

[0086] In this embodiment, the directional control valve 120 is a three-position four-way solenoid directional control valve. For example, the directional control valve 120 has an upward position, a downward position, and a locked position. The directional control valve 120 includes a first electromagnet and a second electromagnet. When the first electromagnet is energized, the directional control valve 120 switches to the upward position; when the second electromagnet is energized, the directional control valve 120 switches to the downward position; when neither the first nor the second electromagnet is energized, the directional control valve 120 is in the locked position (neutral position), the second oil port is closed, and each drive branch is blocked.

[0087] When controller 160 receives a lifting command, it energizes the first electromagnet, and the directional valve 120 switches to the lifting position. Hydraulic oil enters the rodless chamber of hydraulic cylinder 192 through the directional valve 120, pushing the piston rod to extend and driving the lifting platform to rise. When controller 160 receives a lowering command, it energizes the second electromagnet, and the directional valve 120 switches to the lowering position. Hydraulic oil enters the rod chamber of hydraulic cylinder through the directional valve 120. The control oil circuit of hydraulic lock 191 is unloaded, causing the hydraulic lock to close. The return oil from the rodless chamber flows back to the oil tank 150 through speed regulating valve 193 and speed limiting valve 194, and the lifting platform descends smoothly under load.

[0088] When the controller 160 does not receive a rise or fall command, neither the first nor the second electromagnet is energized. The directional valve 120 automatically returns to the locking position (neutral position) under the action of the reset spring, and all oil ports are cut off. The oil inlet and return lines of the hydraulic cylinder 192 are blocked. The lifting platform maintains its current height under the dual locking action of the hydraulic lock 191 and the directional valve 120.

[0089] Thus, by setting up a control box and control buttons, the manual command input and the controller can be centrally arranged, and the controller can directly switch the valve position based on the button input. Therefore, the operator can complete the lifting direction selection in a more intuitive way and reduce the probability of misoperation.

[0090] It should be noted that, in order to further improve the safety of the hydraulic cylinder during the lifting and lowering processes, the lifting system provided in this application embodiment also includes a first limit switch 210 and a second limit switch 220.

[0091] The first limit switch 210 is located at the upper limit position of the lifting platform's upward stroke to detect whether the lifting platform has moved to its highest limit position. The first limit switch 210 is electrically connected to the controller 160 and is used to send an upper limit trigger signal to the controller 160 when triggered.

[0092] The second limit switch 220 is set at the lower limit position of the lifting platform's descent stroke to detect whether the lifting platform has moved to the lowest limit position. The second limit switch 220 is electrically connected to the controller 160 and is used to send a lower limit trigger signal to the controller 160 when triggered.

[0093] It should be understood that the first limit switch 210 and the second limit switch 220 can be mechanical limit switches, proximity switches, photoelectric switches, or magnetic induction switches. Taking a mechanical contact limit switch as an example, the first limit switch 210 is installed at the position where the lifting platform rises to its highest permissible position and can contact the platform body or a stop block fixed on the platform, and the second limit switch 220 is installed at the position where the lifting platform descends to its lowest permissible position and can contact the platform body or a stop block.

[0094] Controller 160 is also configured as follows:

[0095] When the upper limit trigger signal is received, the first electromagnet is de-energized.

[0096] When the lower limit trigger signal is received, the second electromagnet is de-energized.

[0097] During the operation of the lifting system, pressing a control button (such as the up button) energizes the first electromagnet via controller 160, switching the directional valve 120 to the up position. Hydraulic oil is then diverted through the second port 122 to the first and second drive circuits. As the hydraulic oil flows through these circuits, the hydraulic lock 191 opens to establish support. Afterward, the hydraulic oil passes through the speed control valve 193 and enters the two hydraulic cylinders 192, which in turn drive the lifting platform to rise synchronously.

[0098] During the synchronous ascent of the lifting platform, the detection component 195 (such as a stroke sensor) collects the stroke values ​​of the two hydraulic cylinders 192 in real time and transmits them to the controller. The controller 160 compares the synchronization deviation. If it exceeds 0.5mm, it dynamically adjusts the opening of each speed control valve until the two hydraulic cylinders operate synchronously.

[0099] When the lifting platform touches the first limit switch 210, the controller 160 controls the first electromagnet to de-energize, the reversing valve 120 returns to the locking position, and then the hydraulic lock 191 locks instantly, locking the lifting platform at the target height.

[0100] After completing the corresponding operation, such as unloading goods, press the corresponding control button (such as the lowering button). The controller 160 controls the second electromagnet to be energized, and the reversing valve switches to the lowering position. Then, the hydraulic oil flows in the above-mentioned rising state until the lifting platform touches the second limit switch. The controller 160 controls the second electromagnet to be de-energized, the reversing valve 120 returns to the locking position, and the lifting platform stops working.

[0101] With this configuration, the embodiment of this application can achieve automatic stopping by setting the first limit switch 210 and the second limit switch 220, avoiding collisions, impacts or overtravel phenomena caused by the platform due to lag in manual operation, continuous output of commands or inertial overtravel, thereby improving the safety and stability of the lifting system.

[0102] Furthermore, the locking position of the directional valve 120 works in conjunction with the two hydraulic locks 191 to achieve dual safety locking protection in the shutdown state. When the controller de-energizes the first or second electromagnet, the directional valve 120 automatically returns to the neutral position (locked position) under the action of the return spring, and all three ports (first port 121, second port 122, and third port 123) are mutually cut off, cutting off the hydraulic pump's oil supply to the execution branch from the control end. In this way, the linkage locking scheme does not require additional dedicated locking elements; it can be achieved solely through the inherent neutral position function of the directional valve and the standard structure of the hydraulic locks, which reduces system costs and simplifies control logic.

[0103] In one possible implementation, a filter 230 is provided on the oil supply line 140, and the filter 230 is located on the side of the hydraulic pump 110 away from the directional valve 120. The filter is a 100-mesh filter.

[0104] In this way, after the filter 230 intercepts and purifies the particulate impurities in the hydraulic oil, it is sent to the first oil port of the reversing valve for subsequent oil circuit switching and actuator driving. This can improve the purity of the hydraulic oil, thereby improving the safety and stability of the lifting system.

[0105] The various embodiments or implementation methods described in this specification are presented in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0106] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiments may include specific features, structures, or characteristics, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A lifting system, characterized in that, include: Lifting platform; A hydraulic drive assembly, connected to the lifting platform, includes: Hydraulic pump (110); A reversing valve (120) includes a first oil port (121) which is connected to the oil outlet of the hydraulic pump (110). The relief valve (130) has an oil inlet (131) and an oil outlet (132). The oil inlet (131) is connected to the oil supply line (140) between the hydraulic pump (110) and the first oil port (121), and the oil outlet (132) is connected to the oil tank (150). The relief valve (130) is configured such that when the pressure value of the oil supply line (140) is greater than or equal to a preset pressure value, the hydraulic oil flows back to the oil tank (150) through the oil outlet (132).

2. The lifting system according to claim 1, characterized in that, The lifting system also includes a controller (160) and a first pressure sensor (170) disposed on the oil supply line (140). The controller (160) is also electrically connected to the first pressure sensor (170) and the overflow valve (130). The controller (160) is used to control the oil outlet of the overflow valve (130) to open when the pressure value of the first pressure sensor (170) is greater than or equal to the preset pressure value.

3. The lifting system according to claim 2, characterized in that, The oil supply line (140) has a rated pressure value, and the ratio of the preset pressure value to the rated pressure value is greater than or equal to 1.1 and less than or equal to 1.

3.

4. The lifting system according to claim 2 or 3, characterized in that, The reversing valve (120) also includes a second oil port (122); the lifting system includes a first drive branch and a second drive branch; the second oil port is connected to the first drive branch and the second drive branch respectively through a diversion pipe (180).

5. The lifting system according to claim 4, characterized in that, The first drive branch and the second drive branch are sequentially provided with a hydraulic lock (191), a hydraulic cylinder (192), a speed regulating valve (193) and a speed limiting valve (194) along the hydraulic oil flow direction. The speed limiting valve (194) is located at the downstream return oil end of the corresponding drive branch. The output ends of the two hydraulic cylinders (192) are connected to the lifting platform.

6. The lifting system according to claim 5, characterized in that, Each of the hydraulic cylinders (192) is provided with a detection element (195), the detection element (195) and the speed control valve (193) are respectively connected to the controller (160), the controller (160) is configured to: Based on the detection values ​​of the two detection components (195), determine whether the two hydraulic cylinders (192) are operating synchronously; If the two hydraulic cylinders (192) do not operate synchronously, adjust the opening of the two speed control valves (193).

7. The lifting system according to claim 6, characterized in that, The detection element (195) includes a stroke sensor or a second pressure sensor.

8. The lifting system according to claim 2 or 3, characterized in that, The lifting system also includes a control box, the controller is located in the control box, and the control box has several control buttons. The control buttons are connected to the controller (160) and are used to send an upward command or a downward command to the controller (160). The controller (160) is also configured to: According to the up command or the down command, control the reversing valve (120) to switch to the up position or the down position.

9. The lifting system according to claim 8, characterized in that, The reversing valve (120) includes a first electromagnet and a second electromagnet, and the lifting system also includes a first limit switch (210) and a second limit switch (220). The first limit switch (210) is set at the upper limit position of the lifting platform's upward stroke and is electrically connected to the controller (160) to send an upper limit trigger signal to the controller (160) when triggered. The second limit switch (220) is set at the lower limit position of the lowering stroke of the lifting platform and is electrically connected to the controller (160) to send a lower limit trigger signal to the controller (160) when triggered; The controller (160) is also configured to: When the upper limit trigger signal is received, the first electromagnet is de-energized. When the lower limit trigger signal is received, the second electromagnet is de-energized.

10. The lifting system according to any one of claims 1-3, characterized in that, A filter (230) is provided on the oil supply line (140), and the filter (230) is located on the side of the hydraulic pump (110) away from the reversing valve (120).

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