Emergency descent hydraulic control system, control method and aerial work platform

Abstract

This invention discloses an emergency descent hydraulic control system, control method, and aerial work platform to improve emergency safety assurance for aerial work platforms. The hydraulic control system includes an emergency descent valve, a main valve, a gravity descent valve, an actuator assembly, a power source, and auxiliary devices. The power source consists of a main power source and an emergency unit. The outlet of the main power source is connected to the inlet of the main valve, and the outlet of the emergency unit is connected to the inlet of the emergency descent valve. The outlet of the emergency descent valve is connected to the inlet of the main valve, the outlet of the emergency descent valve is connected to the suction port of the gravity descent valve, and the second outlet of the main valve is connected to the inlet of the gravity descent valve. This system ensures the safe descent of personnel to the ground even in cases of valve core jamming, power source damage, or complete vehicle battery depletion.

Description

Technical Field

[0001] This invention relates to a hydraulic control system, and more particularly to an emergency descent hydraulic control system and an aerial work platform using the hydraulic control system. Background Technology

[0002] When performing high-altitude operations, considering the safety of personnel on the aerial work platform, it is necessary to install an emergency descent module to deal with situations where the aerial work platform cannot descend normally under different circumstances.

[0003] With the continuous development of existing hydraulic technology, in the field of aerial work platform technology, the original method of controlling the lifting cylinder using a balance valve has been gradually replaced by a gravity lowering valve. The difference between the two is that the balance valve supplies oil to the rod chamber of the lifting cylinder to retract the cylinder rod and thus complete the lowering action; while the gravity lowering valve circulates the oil in the rodless chamber of the lifting cylinder to the oil tank and uses the load weight of the lifting cylinder to complete the lowering action.

[0004] In the emergency descent module disclosed in the emergency descent system and control method for an aerial work platform with publication number CN115289102A, the emergency descent method is to apply a hydraulic control pressure of 20-30 bar to its hydraulic control port (S port in this invention), so that the balance valve therein opens, and under the action of the cylinder load, the oil in the large chamber of the cylinder flows to the hydraulic oil tank to achieve the effect of emergency descent.

[0005] Generally, not only the descent action requires an emergency module, but other actuators also need to be reset: for example, if the machine is equipped with outrigger cylinders, the outrigger cylinders need to be retracted; the steering cylinders need to reset the tires to the centering position; therefore, the emergency descent module also needs to have the function of resetting other actuators.

[0006] In existing technologies, emergency modules typically use an emergency pump to supply oil to the system in emergencies. However, the emergency pump is driven by an electric motor. Once the vehicle is without power, the emergency module loses its function, and the lifting cylinder cannot be lowered. Only after the vehicle is charged can the workers on the work platform be lowered to a safe position. If there is no charging device at the work site, this still poses a safety hazard. Summary of the Invention

[0007] The present invention aims to solve the problems existing in the prior art. To this end, the present invention provides an emergency descent hydraulic control system that can realize the emergency descent function and simultaneously realize the emergency reset of other actuators; at the same time, it can ensure the safe descent of personnel from the air to the ground even if the valve core is stuck or the vehicle's power is exhausted.

[0008] This invention provides an emergency descent hydraulic control system, characterized in that it includes: an emergency descent valve, a main valve, a gravity descent valve, an actuator assembly, a power source, and auxiliary devices; the power source consists of a main power source and an emergency unit, and the oil outlet of the main power source is connected to the oil inlet of the main valve, the oil outlet of the emergency unit is connected to the oil inlet of the emergency descent valve; the oil outlet of the emergency descent valve is connected to the oil inlet of the main valve, the oil discharge port of the emergency descent valve is connected to the oil suction port of the gravity descent valve, and the second oil outlet of the main valve is connected to the oil inlet of the gravity descent valve;

[0009] The actuator assembly includes an actuator and a lifting cylinder, and the actuator is connected to the first oil outlet of the main valve. The rod chamber and rodless chamber of the lifting cylinder are respectively connected to the first oil outlet and the second oil outlet of the gravity lowering valve.

[0010] The auxiliary device includes a hydraulic oil tank and a filter; and the return port of the emergency lowering valve, the return port of the main valve, and the return port of the gravity lowering valve are all connected to the hydraulic oil tank; the oil outlet of the filter is connected to the oil inlet of the main power source, and the oil inlet of the filter is connected to the hydraulic oil tank.

[0011] The emergency descent valve is equipped with a first switching valve; and the first switching valve is a two-position four-way directional valve, whose valve core is equipped with a first manual switch and a first electric control switch;

[0012] The first switching valve is provided with port 1, port 2, port 3 and port 4. Port 1 and port 2 are located at the oil discharge end of the valve body, and port 3 and port 4 are located at the oil inlet end of the valve body. In the normal position state of the first switching valve, port 1 and port 3 are connected, and port 2 and port 4 are connected. Port 2 is connected to the oil discharge port of the emergency lowering valve, and port 1 is connected to the oil outlet port of the emergency lowering valve.

[0013] Preferably, the emergency lowering valve is equipped with a manual pump unit, and the oil outlet of the manual pump unit is connected to the second port of the first switching valve, and the oil inlet of the manual pump unit is connected to the fourth port of the first switching valve.

[0014] Preferably, the emergency lowering valve is provided with an overflow valve, and the oil inlet of the overflow valve is connected to the second port of the first switching valve, and the oil outlet of the overflow valve is connected to the oil return port of the emergency lowering valve.

[0015] Preferably, the set pressure of the overflow valve is between 30 bar and 40 bar.

[0016] Preferably, the emergency lowering valve is provided with a first check valve, and the oil inlet of the first check valve is connected to the first port of the first switching valve, and the oil outlet of the first check valve is connected to the oil outlet of the emergency lowering valve.

[0017] Preferably, the gravity descent valve is provided with a balance valve, a third switching valve, a proportional valve, a flow compensator, and a fifth check valve;

[0018] The hydraulic control port of the balance valve is connected to the hydraulic control port of the gravity lowering valve, and the oil inlet of the balance valve is connected to the oil outlet of the third switching valve and together connected to the first oil outlet of the gravity lowering valve; the oil outlet of the balance valve is connected to the oil inlet of the third switching valve and together connected to the oil inlet of the gravity lowering valve; and a fifth check valve is provided between the oil inlet of the gravity lowering valve and the oil inlet of the third switching valve.

[0019] The inlet of the proportional valve is connected to the outlet of the fifth check valve, and the outlet of the proportional valve is connected to the inlet of the compensator; the outlet of the compensator is connected to the return port of the gravity descent valve.

[0020] Preferably, the main valve is provided with a second switching valve, a fourth check valve, and a damper; and the second switching valve is equipped with an electric control switch; the first port of the second switching valve is connected to the return port of the main valve, the third port of the second switching valve is connected to the inlet and the first outlet of the main valve, the fourth port of the second switching valve is connected to the return port of the main valve, the second port of the second switching valve is connected to the inlet of the fourth check valve, and the outlet of the fourth check valve is connected to the second outlet of the main valve; the two ends of the damper are connected in parallel with the inlet and outlet of the fourth check valve.

[0021] Preferably, the internal damping channel is in the form of “)(”.

[0022] This invention also provides a control method for the emergency descent hydraulic control system described above, used to control the emergency descent of an aerial work platform when a malfunction occurs. There are three scenarios, and the control method varies depending on the scenario:

[0023] Scenario 1: The main power source fails and cannot supply oil to the system;

[0024] Control method: The emergency unit is energized to supply oil to the system until the actuator is reset; after reset, the first electric control switch is energized. At this time, the hydraulic oil flows from the inlet of the emergency lowering valve to the outlet of the emergency lowering valve and then to the suction port of the gravity lowering valve. At this time, the balance valve opens, and the lifting cylinder completes the lowering action under its own gravity.

[0025] Scenario 2: The first switching valve is stuck and cannot be opened, and at the same time the main power source fails and cannot supply oil to the system;

[0026] Control method: The emergency unit is energized to supply oil to the system. The system runs until the actuator is reset. After the reset, the first manual switch is pressed and held. At this time, the hydraulic oil flows from the inlet of the emergency lowering valve to the outlet of the emergency lowering valve and then to the suction port of the gravity lowering valve. At this time, the balance valve opens, and the lifting cylinder completes the lowering action under its own gravity.

[0027] Scenario 3: The vehicle's battery is completely depleted during operation;

[0028] Control method: Press the first manual switch by hand, and at the same time press the second manual switch of the manual pump unit to supply oil to the system. The hydraulic oil flows from the return port of the emergency lowering valve to the discharge port of the emergency lowering valve and then to the suction port of the gravity lowering valve. At this time, the balance valve opens, and the lifting cylinder completes the lowering action under its own gravity.

[0029] The present invention also provides an aerial work platform, including the emergency descent hydraulic control system described above.

[0030] The advantages of this invention compared to the prior art are as follows: This invention enables emergency reset of other actuators while realizing the emergency descent function; at the same time, it can ensure the safe descent of personnel from the air to the ground even if the valve core is stuck, the power source is damaged, or the vehicle's power is exhausted; in addition, the separate emergency descent valve improves the versatility of the emergency module and facilitates subsequent maintenance and replacement, making its installation method more flexible. Attached Figure Description

[0031] Various objects, features, and advantages of the invention will become more apparent from the following detailed description of preferred embodiments of the invention, taken in conjunction with the accompanying drawings. The drawings are merely illustrative of the invention and are not necessarily drawn to scale. In the drawings, the same reference numerals always denote the same or similar parts. Wherein:

[0032] Figure 1 This is a schematic diagram of an emergency descent hydraulic control system according to an embodiment of the present invention;

[0033] Figure 2 This is a hydraulic schematic diagram of an emergency lowering valve according to an embodiment of the present invention;

[0034] Figure 3 This is a hydraulic schematic diagram of the main valve according to an embodiment of the present invention;

[0035] Figure 4 This is a hydraulic schematic diagram of a gravity lowering valve according to an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the structure of an emergency lowering valve according to an embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram of the structure of an emergency lowering valve according to another embodiment of the present invention.

[0038] In the diagram: 100 Emergency lowering valve, 110 First switching valve, 120 Manual pump unit, 121 Manual operating terminal, 130 Relief valve, 140 First check valve.

[0039] 200 Main valve, 210 Second switching valve, 220 Fourth check valve, 230 Damping valve

[0040] 300 Gravity-driven lowering valve, 310 Balancing valve, 320 Third switching valve, 330 Proportional valve, 340 Flow compensator, 350 Fifth check valve.

[0041] 400 actuator assembly, 410 actuator, 420 lifting cylinder,

[0042] 500 Power source, 510 Main power source, 511 First motor, 512 Main pump, 513 Third check valve, 520 Emergency unit, 521 Second motor, 522 Emergency pump, 523 Second check valve.

[0043] 600 auxiliary device, 610 hydraulic oil tank, 620 filter,

[0044] MV1 First manual switch, MV2 Second manual switch, SV1 First electric control switch, SV2 Second electric control switch, SV3 Third electric control switch, PV1 Proportional switch. Detailed Implementation

[0045] The embodiments of the present invention are described below with reference to the accompanying drawings, and the present invention is further described below with reference to variations of the embodiments of the present invention. It should be understood that the present invention is not limited to the matters described herein, but also includes the scope of modifications or applications made by those skilled in the art within the scope of the claims and the detailed description in the specification, combined with common knowledge and conventional technical means in the art. For ease of description, [the following will be used]. Figure 2 and Figure 3 The markings “①、②、③、④” are respectively called “number one, number two, number three, and number four”.

[0046] An emergency descent hydraulic control system is provided in this embodiment of the invention, characterized in that it includes: an emergency descent valve 100, a main valve 200, a gravity descent valve 300, an actuator assembly 400, a power source 500, and an auxiliary device 600.

[0047] like Figure 1As shown, the power source 500 consists of a main power source 510 and an emergency unit 520. The main power source 510 comprises a first motor 511, a main pump 512, and a third check valve 513. The main pump 512 is driven by the first motor 511 and serves as the main power source for the hydraulic system. The third check valve 513 is connected to the hydraulic system of the main pump 512. The main power source 510 has an oil inlet and an oil outlet. The oil inlet is externally connected to a filter 620, which is connected to the hydraulic oil tank 610. The oil outlet of the main power source 510 is connected to the oil inlet (referred to as port P, marked as port P2) of the main valve 200. The oil outlet of the emergency unit 520 is connected to the oil inlet (referred to as port P, marked as port P) of the emergency lowering valve 100. The oil outlet (marked as port P1) of the emergency lowering valve 100 is connected to and communicates with the oil inlet (port P2) of the main valve 200, and the oil discharge port (referred to as port L) of the emergency lowering valve 100 is connected to the hydraulic control port (marked as port S) of the gravity lowering valve 300.

[0048] The second oil outlet (referred to as F port) of the main valve 200 is connected to the oil inlet (P3 port) of the gravity lowering valve 300. The actuator assembly 400 includes a lifting cylinder 420 and an actuator 410, and the actuator 410 is connected to the first oil outlet (H port) of the main valve 200. The rod-side chamber and the rodless chamber of the lifting cylinder 420 are respectively connected to the first oil outlet (A port) and the second oil outlet (B port) of the gravity lowering valve 300.

[0049] The emergency unit 520 consists of a second motor 521, an emergency pump 522, and a second check valve 523. The second motor 521 drives the emergency pump 522 to operate and supplies oil to the system through the second check valve 523.

[0050] The actuators described in this embodiment include, but are not limited to, hydraulic motors and hydraulic cylinders, which are hydraulic actuators other than lifting cylinders. In this embodiment, the lifting cylinder specifically refers to the hydraulic cylinder in the hydraulic lifting platform that performs lifting actions in the height direction. In this embodiment, the distinction between lifting cylinders and other hydraulic actuators is merely for ease of description and should not be misunderstood.

[0051] The auxiliary device 600 includes a hydraulic oil tank 610 and a filter 620; and the return port (T port) of the emergency lowering valve 100, the return ports (T2 port, T3 port) of the main valve 200, and the return port (T1 port) of the gravity lowering valve 300 are all connected to the hydraulic oil tank 610 through oil pipes.

[0052] The oil outlet of the filter 620 is connected to the oil inlet of the main power source 510 (i.e., connected to the oil inlet of the main pump 512), and the oil inlet of the filter 620 is connected to the hydraulic oil tank 610, serving as the oil supply end.

[0053] The emergency lowering valve 100 includes a first switching valve 110; the main body of the first switching valve 110 is a two-position four-way directional valve, with a first manual switch MV1 and a first electric control switch SV1 located at its valve core. The first switching valve 110 has ports 1, 2, 3, and 4, where ports 1 and 2 are located at the oil discharge end of the valve body, and ports 3 and 4 are located at the oil inlet end of the valve body. The first manual switch MV1 refers to a push-button manual switch; pressing the switch with a finger and releasing the finger resets the switch. The first electric control switch SV1 refers to a common electromagnetic induction switch, typically requiring 12V control. As a common two-position four-way directional valve, the normal position of the first switching valve 110 is such that port 1 is connected to port 3, and port 2 is connected to port 4; and port 2 is connected to the drain port (L port) of the emergency lowering valve 100; port 1 is connected to the outlet port (P1 port) of the emergency lowering valve 100, and a first check valve 140 is connected between port 1 of the first switching valve 110 and the outlet port (P1 port) of the emergency lowering valve 100.

[0054] The advantages of setting up a separate emergency lowering valve 100 are mainly reflected in two aspects:

[0055] First: Versatility. The separate emergency lowering valve 100 allows it to be used in various series of complete machines, not limited to scissor lifts or boom lifts, and is not limited to any type of aerial work platform with any lifting height.

[0056] Second: It facilitates maintenance and replacement; the separate emergency lowering valve 100 is beneficial for after-sales maintenance and reduces maintenance costs.

[0057] Further, such as Figure 2 The emergency lowering valve 100 shown also includes a manual pump unit 120. The oil outlet of the manual pump unit 120 is connected to port number two of the first switching valve 110, and the oil inlet of the manual pump unit 120 is connected to port number four of the first switching valve 110. It is easy to understand that by repeatedly pressing the manual pump unit 120, a small amount of hydraulic oil (relative to an electric pump) can be supplied; that is, manual control serves as an auxiliary measure in the event of a power outage.

[0058] The manual pump unit 120 is equipped with a second manual switch (MV2), which can be a plunger pump, such as a common embodiment—a manual jack. Figure 5 and Figure 6 In the structural schematic diagram of the emergency lowering valve in the two embodiments shown, the second manual switch MV2 can be configured in two forms, wherein the manual operation end 121 can be a button structure or a rocker arm structure.

[0059] exist Figure 5 In the illustrated embodiment, a rocker arm pressurization structure is used. Specifically, the second manual switch MV2 requires a cylindrical rod, typically a steel pipe, which is inserted into the cylindrical sleeve (manual operation end 121) of the second manual switch MV2. Then, the cylindrical rod is pressed up and down repeatedly by hand to achieve the function of supplying oil to the manual pump unit 120. The form of the second manual switch MV2 in this embodiment is generally suitable for large aerial work platforms, that is, situations where the system pressure is high.

[0060] exist Figure 5 In the illustrated embodiment, a button-type pressurization structure is used. Specifically, the second manual switch MV2 can be pressed directly by hand, and repeated pressing can achieve the function of supplying oil to the manual pump unit 120. The form of the second manual switch MV2 in this embodiment is generally suitable for small aerial work platforms, that is, when the system pressure is low.

[0061] The emergency descent valve also has an anti-accidental touch function. To facilitate pressing the first manual switch MV1 and the second manual switch MV2, the emergency descent valve 100 is usually positioned in a location easily accessible for manual operation. However, during operation, personnel may accidentally touch the second manual switch MV2. In the operation method provided by this invention, the first manual switch MV1 must be pressed first, followed by continuous pressing of the second manual switch MV2 to initiate an emergency descent. Therefore, to complete the emergency descent action, both the first manual switch MV1 and the second manual switch MV2 must be pressed simultaneously. This prevents the emergency descent from occurring when personnel accidentally touch the second manual switch MV2. Through the linkage design between the two, the reliability of the emergency descent module is improved.

[0062] The emergency lowering valve 100 is equipped with an overflow valve 130, and the oil inlet of the overflow valve 130 is connected to the second port of the first switching valve 110, and the oil outlet of the overflow valve 130 is connected to the T port of the emergency lowering valve 100.

[0063] Preferably, the set pressure of the relief valve 130 is between 30 bar and 40 bar. The set pressure of the relief valve 130 is designed based on the opening pressure of the balance valve 310. Its purpose is to protect the balance valve 310 from damage due to excessive system pressure. Of course, the specific set pressure of the relief valve 130 can be designed according to the specific opening pressure of the balance valve 310. For balance valves with a smaller opening ratio, the set pressure can be larger, and vice versa.

[0064] Preferably, the emergency lowering valve 100 is provided with a first check valve 140, and the oil inlet of the first check valve 140 is connected to the first port of the first switching valve 110, and the oil outlet of the first check valve 140 is connected to the oil outlet (P1 port) of the emergency lowering valve 100. The purpose of providing the check valve is to prevent other actuators 410 from overflowing when the oil inlet (P2 port) of the main valve 200 is connected to the oil inlet of the relief valve 130, and the other actuators 410 reach the set pressure of the relief valve 130. At the same time, the first check valve 140 can also prevent hydraulic oil backflow and play a protective role for the system.

[0065] like Figure 4 As shown, the gravity lowering valve 300 is equipped with a balance valve 310, a third switching valve 320, a proportional valve 330, a flow compensator 340, and a fifth check valve 350.

[0066] A balancing valve is used to adjust the relative balance of pressure on both sides. The hydraulic control port of the balancing valve 310 is connected to the hydraulic control port (marked as port S) of the gravity lowering valve 300. The inlet of the balancing valve 310 is connected to the outlet of the third switching valve 320 and together they are connected to the first outlet (port A) of the gravity lowering valve 300. The outlet of the balancing valve 310 is connected to the inlet of the third switching valve 320 and together they are connected to the outlet of the gravity lowering valve 300. A fifth check valve 350 is provided between the outlet of the gravity lowering valve 300 and the inlet of the third switching valve 320. The third switching valve 320 and the fifth check valve 350 are connected in series between the inlet and outlet of the gravity lowering valve 300. The third switching valve 320 is a two-position two-way solenoid valve, and the actuator is a third solenoid switch SV3.

[0067] The inlet of the proportional valve 330 is connected to the outlet of the fifth check valve 350, and the outlet of the proportional valve 330 is connected to the inlet of the compensator 340; the outlet of the compensator 340 is connected to the T1 port of the gravity lowering valve 300. The gravity lowering valve is also equipped with a return oil passage connecting port B and port T1.

[0068] In some embodiments of the present invention, the third electronic control switch SV3 may not be provided. Its function is to play a certain auxiliary safety role and not affect the lowering function of the lifting cylinder 420.

[0069] like Figure 3As shown, the main valve 200 includes a second switching valve 210, a fourth check valve 220, and a hydraulic damper 230. Specifically, the second switching valve 210 is a two-position four-way hydraulic directional valve. The second switching valve 210 is equipped with an electronically controlled switch SV2; port 1 of the second switching valve 210 is connected to port T3 of the main valve 200; port 3 of the second switching valve 210 is connected to ports P2 and H of the main valve 200; port 4 of the second switching valve 210 is connected to port T2 of the main valve 200; port 2 of the second switching valve 210 is connected to the inlet of the fourth check valve 220; the outlet of the fourth check valve 220 is connected to port F of the main valve 200; the two ends of the damper 230 are connected in parallel to the inlet and outlet of the fourth check valve 220.

[0070] In one embodiment of the present invention, the internal channel of the damper 230 is in the form of ")(". The conventional channel type, "︱︱", often causes abnormal noise during vehicle descent due to the impact of excessive instantaneous flow on the oil inlet at the damper end. The ")(" type damper can mitigate the instantaneous impact of the flow, thereby eliminating the abnormal noise.

[0071] The hydraulic cylinders included in the aforementioned actuator 410 vary in different models of aerial work platforms. In scissor lift aerial work platforms, they may include outrigger cylinders to support the entire aerial work platform, as well as steering cylinders. In boom lift aerial work platforms, they may include other cylinders besides the lifting cylinder 420, but are not limited to floating cylinders.

[0072] A control method for an emergency descent hydraulic control system, used to control the emergency descent of an aerial work platform when a malfunction occurs. Depending on the situation, the control method includes:

[0073] Scenario 1: The main power source 510 fails and cannot supply oil to the system;

[0074] Control method: The emergency unit 520 is energized to supply oil to the system until the actuator 410 is reset; after reset, the first electrical control switch SV1 is energized. At this time, the hydraulic oil flows from the inlet of the emergency lowering valve 100 to the outlet of the emergency lowering valve 100 and then to the suction port of the gravity lowering valve 300. At this time, the balance valve 310 is opened, and the lifting cylinder 420 completes the lowering action under its own gravity.

[0075] Scenario 2: The first switching valve 110 is stuck and cannot be opened, and at the same time the main power source 510 fails and cannot supply oil to the system;

[0076] Control method: The emergency unit 520 is energized to supply oil to the system. When the actuator 410 is reset, the first manual switch MV1 is pressed and held by hand. At this time, the hydraulic oil flows from the inlet of the emergency lowering valve 100 to the outlet of the emergency lowering valve 100 and then to the suction port of the gravity lowering valve 300. At this time, the balance valve 310 is opened, and the lifting cylinder 420 completes the lowering action under its own gravity.

[0077] Scenario 3: The vehicle's battery is completely depleted during operation;

[0078] Control method: Press the first manual switch MV1 by hand, and at the same time press the second manual switch MV2 of the manual pump unit 120 to supply oil to the system. The hydraulic oil flows from the return port of the emergency lowering valve 100 to the discharge port of the emergency lowering valve 100 and then to the suction port of the gravity lowering valve 300. At this time, the balance valve 310 opens, and the lifting cylinder 420 completes the lowering action under its own gravity.

[0079] The above are three common situations requiring emergency descent in engineering. The control method of the emergency descent hydraulic control system provided by this invention is applicable to these three situations. The first situation is less likely to occur. The failure of the main power source is often due to the aging of the pump motor, or the wear of the gears inside the pump, or the exhaustion of hydraulic oil. In summary, the above situations are often caused by the long service life of the vehicle.

[0080] The second situation occurs more frequently. Because the internal structure of the switching valve is relatively compact, once the hydraulic oil is contaminated, the valve will often get stuck, meaning that the valve core cannot switch positions.

[0081] The third situation occurs frequently in actual construction. Due to the low safety awareness of on-site construction personnel, in many cases, they wait until the vehicle's battery is completely depleted before charging it. This means that the construction personnel have to wait for the vehicle to charge for a period of time before they can descend. In addition, the on-site construction environment is relatively complex and electricity is inconvenient. At this time, the emergency descent function is particularly important.

[0082] The present invention also provides an aerial work platform, including the emergency descent hydraulic control system described above.

[0083] In summary, the technical advantages of this invention are as follows: It enables emergency descent while simultaneously resetting other actuators; it also ensures the safe descent of personnel to the ground even in cases of valve core jamming, power source failure, or vehicle battery depletion; furthermore, the separate emergency descent valve 100 improves the versatility of the emergency module and facilitates subsequent maintenance and replacement, making its installation more flexible; the emergency descent valve also has an anti-accidental activation function, effectively preventing the platform from descending due to accidental manual activation of the emergency descent valve.

Claims

1. An emergency descent hydraulic control system, characterized in that, include: Emergency lowering valve (100), main valve (200), gravity lowering valve (300), actuator assembly (400), power source (500) and auxiliary device (600); The power source (500) consists of a main power source (510) and an emergency unit (520). The oil outlet of the main power source (510) is connected to the oil inlet of the main valve (200), and the oil outlet of the emergency unit (520) is connected to the oil inlet of the emergency lowering valve (100). The oil outlet of the emergency lowering valve (100) is connected to the oil inlet of the main valve (200), the oil discharge port of the emergency lowering valve (100) is connected to the oil suction port of the gravity lowering valve (300), and the second oil outlet of the main valve (200) is connected to the oil inlet of the gravity lowering valve (300). The actuator assembly (400) includes an actuator (410) and a lifting cylinder (420), and the actuator (410) is connected to the first oil outlet of the main valve (200), and the rod chamber and rodless chamber of the lifting cylinder (420) are connected to the first oil outlet and the second oil outlet of the gravity lowering valve (300), respectively. The auxiliary device (600) includes a hydraulic oil tank (610) and a filter (620); the return port of the emergency lowering valve (100), the return port of the main valve (200), and the return port of the gravity lowering valve (300) are all connected to the hydraulic oil tank (610); the outlet of the filter (620) is connected to the inlet of the main power source (510), and the inlet of the filter (620) is connected to the hydraulic oil tank (610); The emergency lowering valve (100) is provided with a first switching valve (110); and the first switching valve (110) is a two-position four-way reversing valve. The valve core of the first switching valve is provided with a first manual switch (MV1) and a first electric control switch (SV1). The emergency lowering valve (100) is provided with a manual pump unit (120), and the oil outlet of the manual pump unit (120) is connected to the second port of the first switching valve (110), and the oil inlet of the manual pump unit (120) is connected to the fourth port of the first switching valve (110). The first switching valve (110) is provided with port 1, port 2, port 3 and port 4. Port 1 and port 2 are located at the oil discharge end of the valve body, and port 3 and port 4 are located at the oil inlet end of the valve body. The normal position of the first switching valve (110) is that port 1 and port 3 are connected, and port 2 and port 4 are connected. Port 2 is connected to the oil discharge port of the emergency lowering valve (100), and port 1 is connected to the oil outlet port of the emergency lowering valve (100).

2. The emergency descent hydraulic control system according to claim 1, characterized in that, The emergency lowering valve (100) is equipped with an overflow valve (130), and the oil inlet of the overflow valve (130) is connected to the second port of the first switching valve (110), and the oil outlet of the overflow valve (130) is connected to the oil return port of the emergency lowering valve (100).

3. The emergency descent hydraulic control system according to claim 2, characterized in that, The set pressure of the relief valve (130) is between 30 bar and 40 bar.

4. The emergency descent hydraulic control system according to claim 1, characterized in that, The emergency lowering valve (100) is provided with a first check valve (140), and the oil inlet of the first check valve (140) is connected to the first port of the first switching valve (110), and the oil outlet of the first check valve (140) is connected to the oil outlet of the emergency lowering valve (100).

5. The emergency descent hydraulic control system according to claim 1, characterized in that, The gravity lowering valve (300) is equipped with a balance valve (310), a third switching valve (320), a proportional valve (330), a flow compensator (340), and a fifth check valve (350). The hydraulic control port of the balance valve (310) is connected to the hydraulic control port of the gravity lowering valve (300), and the oil inlet of the balance valve (310) is connected to the oil outlet of the third switching valve (320) and together connected to the first oil outlet of the gravity lowering valve (300); the oil outlet of the balance valve (310) is connected to the oil inlet of the third switching valve (320) and together connected to the oil inlet of the gravity lowering valve (300); and a fifth check valve (350) is provided between the oil inlet of the gravity lowering valve (300) and the oil inlet of the third switching valve (320). The inlet of the proportional valve (330) is connected to the outlet of the fifth check valve (350), and the outlet of the proportional valve (330) is connected to the inlet of the compensator (340); the outlet of the compensator (340) is connected to the return port of the gravity lowering valve (300).

6. The emergency descent hydraulic control system according to claim 1, characterized in that, The main valve (200) is equipped with a second switching valve (210), a fourth check valve (220), and a damper (230); the second switching valve (210) is equipped with an electric control switch (SV2); the first port of the second switching valve (210) is connected to the return port of the main valve (200), the third port of the second switching valve (210) is connected to the inlet port and the first outlet port of the main valve (200), the fourth port of the second switching valve (210) is connected to the return port of the main valve (200), the second port of the second switching valve (210) is connected to the inlet port of the fourth check valve (220), and the outlet port of the fourth check valve (220) is connected to the second outlet port of the main valve (200); the two ends of the damper (230) are connected in parallel with the inlet port and the outlet port of the fourth check valve (220).

7. An emergency descent hydraulic control system according to claim 6, characterized in that, The internal channel of the damper (230) is of the form of "" (".

8. A control method for the emergency descent hydraulic control system according to claim 5, used to control the emergency descent of an aerial work platform when a malfunction occurs, characterized in that, Depending on the specific circumstances, control methods include: Scenario 1: The main power source (510) fails and cannot supply oil to the system; Control method: The emergency unit (520) is energized to supply oil to the system until the actuator (410) is reset; after reset, the first electric control switch (SV1) is energized. At this time, the hydraulic oil flows from the inlet of the emergency lowering valve (100) to the outlet of the emergency lowering valve (100) and then to the suction port of the gravity lowering valve (300). At this time, the balance valve (310) is opened, and the lifting cylinder (420) completes the lowering action under its own gravity. Scenario 2: The first switching valve (110) becomes stuck and cannot be opened, and at the same time the main power source (510) fails and cannot supply oil to the system; Control method: The emergency unit (520) is energized to supply oil to the system. When the actuator (410) is reset, the first manual switch (MV1) is pressed and held by hand. At this time, the hydraulic oil flows from the inlet of the emergency lowering valve (100) to the outlet of the emergency lowering valve (100) and then to the suction port of the gravity lowering valve (300). At this time, the balance valve (310) is opened, and the lifting cylinder (420) completes the lowering action under its own gravity. Scenario 3: The vehicle's battery is completely depleted during operation; Control method: Press the first manual switch (MV1) by hand, and at the same time press the second manual switch (MV2) of the manual pump unit (120) to supply oil to the system. The hydraulic oil flows from the return port of the emergency lowering valve (100) to the discharge port of the emergency lowering valve (100) and then to the suction port of the gravity lowering valve (300). At this time, the balance valve (310) opens, and the lifting cylinder (420) completes the lowering action under its own gravity.

9. An aerial work platform, characterized in that, Includes the emergency descent hydraulic control system as described in any one of claims 1 to 6.

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