Hydraulic scissor lift anti-dumping automatic adjustment device and working method thereof

Abstract

The present invention relates to an automatic anti-dumping adjustment device for a hydraulic scissor lift and a working method thereof, and is characterized in that the automatic anti-dumping adjustment device for the hydraulic scissor lift comprises two groups of scissor lifts and an anti-dumping actuator arranged in parallel for jointly lifting a car, the two groups of scissor lifts are respectively a first scissor lift and a second scissor lift, the first scissor lift and the second scissor lift are respectively provided with a first main hydraulic oil circuit and a second main hydraulic oil circuit, the automatic anti-dumping adjustment device for the hydraulic scissor lift of the present invention can automatically adjust the first and second main hydraulic oil circuits, so that the oil pressures in the first cavity and the second cavity are the same, so that the lifting heights of the first scissor lift and the second scissor lift are consistent, and the risk of car dumping is reduced.

Description

Technical field:

[0002] The invention relates to an automatic anti-dumping regulating device for a hydraulic scissor lift and a working method thereof. Background technology:

[0004] During the maintenance process, a car needs to be lifted by a lift. It is common for the car to fall due to unbalanced lifting, which causes great danger and loss. For hydraulic lifts, the height of the lift is mainly changed by changes in oil pressure. However, this type of lift may have aging or squeezing of the oil pipes, resulting in abnormal oil transportation, which makes the lifting heights on both sides of the scissor lift inconsistent, causing the car to tip over.

[0005] Existing invention patent: a lift anti-tilt alarm device, application number CN201810337134.0, the patent installs a sensor on the top of the car to detect the car's tilt angle. When the car tilts, an alarm is issued, and the power is cut off, so that the lift does not work. There is also a double-column car lift tipping alarm device, application number: CN201811423999.5, which has not been authorized and is a patent applied for by the applicant. The patent uses a pressure sensor to determine whether the car is in danger of tipping, generates an alarm, and cuts off the lift power.

[0006] The above two patent applications mainly cut off the working circuit of the lift when unbalanced lifting occurs, and cannot automatically adjust the uneven heights on both sides of the lift. Summary of the invention:

[0008] In view of the above problems, the present invention proposes an automatic anti-dumping adjustment device for a hydraulic scissor lift and a working method thereof. The automatic anti-dumping adjustment device for a hydraulic scissor lift can change the situation where the heights of two lifts are not uniform.

[0009] The anti-dumping automatic adjustment device for a hydraulic scissor lift of the present invention is characterized in that it comprises two groups of scissor lifts and an anti-dumping actuator arranged in parallel for jointly lifting a car, the two groups of scissor lifts are respectively a first scissor lift and a second scissor lift, the first scissor lift and the second scissor lift are respectively provided with a first main hydraulic oil circuit and a second main hydraulic oil circuit, the anti-dumping actuator comprises a valve body, a valve core arranged in the valve body and an oil storage tank arranged outside the valve body, the valve body is provided with a first cavity connected to the first main hydraulic oil circuit, a second cavity connected to the second main hydraulic oil circuit and an intermediate cavity between the first cavity and the second cavity, the intermediate cavity is provided with the valve core, and the middle part of the valve body is provided with A first pipeline connected to the oil storage tank, a fourth pipeline connected to the oil storage tank, a second pipeline connected to the first cavity and the middle cavity, and a third pipeline connected to the second cavity and the middle cavity, the inlet of the second pipeline connected to the middle cavity is close to the second cavity, the inlet of the third pipeline connected to the middle cavity is close to the first cavity, the fourth pipeline has two connecting inlets to the middle cavity, one of which is close to the first cavity and the other is close to the second cavity, a one-way valve is provided on the inlet of the second pipeline and the first cavity, and the inlet of the third pipeline and the second cavity, an oil pump is connected in series on the first pipeline, the valve core includes a central stepped shaft whose diameter matches the middle cavity and baffles provided at both ends of the central stepped shaft, and both sides of the central portion of the central stepped shaft have reduced diameter sections.

[0010] Furthermore, the above-mentioned central stepped shaft includes a middle shaft section, a reduced diameter section located on both sides of the middle shaft section, and an outer shaft section located outside the reduced diameter section. The first pipeline is located at the entrance of the intermediate cavity and has a first rectangular recessed groove, and the width of the middle shaft section is smaller than the width of the rectangular recessed groove.

[0011] Furthermore, the fourth pipeline is branched into two branches in the valve body, and a second rectangular recessed groove is provided at the connecting inlet between the two branches and the middle cavity.

[0012] Furthermore, the first, second, third and fourth pipelines are not connected.

[0013] Furthermore, the length of the central stepped axis is greater than the length of the middle cavity.

[0014] Furthermore, receivers and transmitters of photoelectric sensors are respectively provided on opposite surfaces of the two lifting plates on the first scissor lift and the second scissor lift, and the receivers and transmitters of the photoelectric sensors are electrically connected to the controller, and the controller is electrically connected to the driving motor of the oil pump.

[0015] The working method of the automatic anti-dumping adjustment device of a hydraulic scissor lift of the present invention is characterized in that: the automatic anti-dumping adjustment device of the hydraulic scissor lift comprises two groups of scissor lifts and anti-dumping actuators arranged in parallel for jointly lifting a car, the two groups of scissor lifts are respectively a first scissor lift and a second scissor lift, the first scissor lift and the second scissor lift are respectively provided with a first main hydraulic oil circuit and a second main hydraulic oil circuit, the anti-dumping actuator comprises a valve body, a valve core arranged in the valve body and an oil storage tank arranged outside the valve body, the valve body is provided with a first cavity connected to the first main hydraulic oil circuit, a second cavity connected to the second main hydraulic oil circuit and an intermediate cavity between the first cavity and the second cavity, the intermediate cavity is provided with the valve core, the middle part of the valve body is provided with a first pipeline connected to the oil storage tank, a fourth pipeline connected to the oil storage tank, and a first pipeline connected to the oil storage tank. A second pipeline connecting the cavity and the middle cavity, a third pipeline connecting the second cavity and the middle cavity, an inlet connecting the second pipeline and the middle cavity is close to the second cavity, an inlet connecting the third pipeline and the middle cavity is close to the first cavity, and there are two connecting inlets between the fourth pipeline and the middle cavity, one of which is close to the first cavity and the other is close to the second cavity. A one-way valve is provided on the inlet between the second pipeline and the first cavity and the inlet between the third pipeline and the second cavity. An oil pump is connected in series on the first pipeline. The valve core includes a central stepped shaft whose diameter matches the middle cavity and baffles provided at both ends of the central stepped shaft. Both sides of the central part of the central stepped shaft have reduced diameter sections. During operation, when the lifting heights of the first scissor lift and the second scissor lift are the same, the anti-dumping actuator is not started, and when the lifting heights of the first scissor lift and the second scissor lift are different, the anti-dumping actuator is started.

[0016] Furthermore, since the first cavity is connected with the first main hydraulic oil circuit, the first main hydraulic oil circuit flows into the first cavity, and the second cavity is connected with the second main hydraulic oil circuit, the second main hydraulic oil circuit flows into the second cavity. Because the first cavity and the second cavity in the valve body have the same structure, when the oil pressure in the first main hydraulic oil circuit and the second main hydraulic oil circuit are the same, the amount of oil flowing into the first cavity and the second cavity is the same. At this time, the pressures in the first cavity and the second cavity are the same, so that the surface pressures of the two baffles of the valve core are the same, and the valve core is in the middle position and does not move; when an abnormality occurs in the first or second main hydraulic oil circuit, such as when the second main hydraulic oil circuit is blocked, the pressure in the second cavity will be lower than that in the first cavity, causing the heights of the first scissor lift and the second scissor lift to be inconsistent, and the receiver in the photoelectric sensor cannot receive the signal, and the motor signal of the oil pump is given, and the oil pump starts to pump oil; since the valve core can move axially, it will cause the valve core to approach the first Second cavity, at this time, due to continuous oil pumping, the oil in the oil storage tank is input from the first pipeline to the middle cavity, and the oil cannot enter the right part of the middle cavity and return to the oil storage tank from the third pipeline. At this time, the one-way valve of the second cavity will be pushed open, and the oil will enter the second cavity. Since the second cavity is connected to the second main hydraulic oil circuit, the oil pressure of the second main hydraulic oil circuit can be continuously increased, and the second scissor lift can operate normally. The pressure difference between the two cavities is reduced. With continuous oil pumping, the oil in the second cavity can be well compensated; when the oil pressure difference between the first and second cavities is slowly reduced, the valve body will slowly slide toward the first cavity, but before the valve core slides to the center of the valve body, due to the inconsistency between the size of the valve core and the inlet of each pipeline, the oil pressure flowing into the third pipeline will still be greater than the oil pressure of the second pipeline. At this time, more oil will continue to be pumped into the second cavity until the oil pressure of the first and second cavities is the same and the valve core slides to the center of the valve body before stopping.

[0017] Furthermore, the oil pressure in the first and second cavities is the same, that is, the valve core is located in the center of the valve body, but the receiver of the sensor is blocked by maintenance personnel or other reasons. At this time, the motor of the oil pump will also be activated, so that the oil pump can pump oil. At this time, since the first and second main hydraulic pipes work normally, the pressure in the first and second cavities is still the same, and the oil enters the middle cavity through the first pipeline from the oil storage tank, and finally flows back to the oil storage tank through the fourth pipeline; although the oil will flow into the second and third pipelines, the second and third pipelines entering the first and second cavities have one-way valves. At this time, since the second and third pipelines are connected to the fourth pipeline, the pressure is too small to open the one-way valve, and finally the oil still flows back to the oil storage tank.

[0018] The hydraulic scissor lift anti-dumping automatic adjustment device of the present invention can automatically adjust the first and second main hydraulic oil circuits, so that the oil pressures in the first cavity and the second cavity are the same, so that the lifting heights of the first scissor lift and the second scissor lift are consistent, reducing the risk of automobile dumping. Description of the drawings:

[0020] Figure 1 It is a working principle diagram of the present invention;

[0021] Figure 2 It is a working state diagram of the anti-dumping actuator;

[0022] Figure 3 It is another working state diagram of the anti-dumping actuator;

[0023] Figure 4 It is the control schematic diagram;

[0024] Where K is the car. Specific implementation method:

[0026] The hydraulic scissor lift anti-dumping automatic adjustment device of the present invention comprises two sets of scissor lifts 1 and an anti-dumping actuator 2 arranged in parallel for jointly lifting a car. The two sets of scissor lifts 1 are respectively a first scissor lift 101 and a second scissor lift 102. The first scissor lift 101 and the second scissor lift 102 have the same structure. The first scissor lift 101 and the second scissor lift 102 are respectively provided with a first main hydraulic oil circuit 3 and a second main hydraulic oil circuit 4, which are independent pipelines. The first main hydraulic oil circuit 3 is the hydraulic main circuit or branch circuit of the lifting cylinder of the first scissor lift 101, and the second main hydraulic oil circuit 4 is the hydraulic main circuit or branch circuit of the lifting cylinder of the second scissor lift 102. The anti-dumping actuator 2 includes a valve body 5 (the valve body 5 is made of metal material), a valve core 6 arranged in the valve body (the valve core 6 can be made of rubber material) and an oil storage tank 7 (for storing hydraulic oil) arranged outside the valve body. The valve body 5 is provided with a first cavity 8 connected with the first main hydraulic oil circuit 3, a second cavity 9 connected with the second main hydraulic oil circuit 4 and an intermediate cavity 10 located between the first cavity and the second cavity, and the valve core 6 is arranged in the intermediate cavity 10, and the valve core 6 is axially movable in the intermediate cavity.

[0027] The middle part of the valve body 5 is provided with a first pipeline 11 communicating with the oil storage tank 7, a fourth pipeline 12 communicating with the oil storage tank 7, a second pipeline 13 communicating with the first cavity 8 and the intermediate cavity 10, and a third pipeline 14 communicating with the second cavity 9 and the intermediate cavity 10. The inlet of the second pipeline 13 communicating with the intermediate cavity 10 is close to the second cavity 9, the inlet of the third pipeline 14 communicating with the intermediate cavity 10 is close to the first cavity 8, and the fourth pipeline 12 has two communicating inlets with the intermediate cavity 10, one of which is close to the first cavity 8. , the other is close to the second cavity 9, a one-way valve 15 (the one-way valve 15 can be a one-way ball valve) is provided on the second pipeline 13 and the inlet of the first cavity 8, and the third pipeline 14 and the inlet of the second cavity 9, the first pipeline 11 is connected in series with an oil pump 16, and the oil pump 16 is driven by an oil pump motor 28, the valve core 6 includes a central stepped shaft 17 whose diameter matches the intermediate cavity 10 and baffles 18 provided at both ends of the central stepped shaft 17, and both sides of the central part of the central stepped shaft 17 have reduced diameter sections 19.

[0028] Furthermore, for the sake of reasonable design, the above-mentioned central stepped shaft 17 includes a middle shaft section 20, a reduced diameter section 19 located on both sides of the middle shaft section, and an outer shaft section 21 located outside the reduced diameter section 19. The first pipeline 11 has a first rectangular recessed groove 22 at the entrance of the middle cavity. The first rectangular recessed groove 22 is an annular groove surrounding the middle cavity. The width of the middle shaft section is smaller than the width of the rectangular recessed groove, and the width is only slightly smaller, so that after the central stepped shaft 17 moves axially, the hydraulic oil enters the first pipeline 11 and the first rectangular recessed groove 22, and then can enter the reduced diameter section 19 of the middle cavity, and flow back to the oil storage tank 7 from the fourth pipeline 12.

[0029] Furthermore, for reasonable design, the fourth pipeline 12 is branched into two branches 23 in the valve body. The two branches 23 have a second rectangular recessed groove 24 at the entrance connecting the middle cavity 10. The second rectangular recessed groove 24 is also an annular groove surrounding the middle cavity.

[0030] The first, second, third and fourth pipelines are not connected to each other to ensure that they work independently of each other.

[0031] Furthermore, the length of the central stepped shaft is greater than the length of the middle cavity. Since the length of the central stepped shaft is greater than the length of the middle cavity, the central stepped shaft can move axially in the middle cavity.

[0032] Furthermore, a receiver 25 and a transmitter 26 of a photoelectric sensor are respectively provided on opposite surfaces of the two lifting plates 29 on the first scissor lift and the second scissor lift. The receiver and the transmitter of the photoelectric sensor are electrically connected to the controller 27, and the controller 27 is electrically connected to the drive motor 28 of the oil pump. The receiver 25 and the transmitter 26 of the photoelectric sensor are installed on opposite surfaces of the two lifting plates 29. When the lifting heights of the lifting plates 29 where the receiver 25 and the transmitter 26 are located are consistent, the receiver 25 can receive the transmission signal of the transmitter 26. At this time, the controller does not drive the drive motor 28 and the oil pump to work. When the lifting heights of the lifting plates 29 where the receiver 25 and the transmitter 26 are located are inconsistent, the receiver 25 cannot receive the transmission signal of the transmitter 26. At this time, the controller drives the drive motor 28 and the oil pump to work, thereby achieving the same pressure in the first cavity 8 and the second cavity 9, so that the lifting heights of the lifting plates 29 return to consistency.

[0033] The working method of the automatic anti-dumping adjustment device of a hydraulic scissor lift of the present invention, the automatic anti-dumping adjustment device of the hydraulic scissor lift comprises two groups of scissor lifts and anti-dumping actuators arranged in parallel for jointly lifting a car, the two groups of scissor lifts are respectively a first scissor lift and a second scissor lift, the first scissor lift and the second scissor lift are respectively provided with a first main hydraulic oil circuit and a second main hydraulic oil circuit, the anti-dumping actuator comprises a valve body, a valve core arranged in the valve body and an oil storage tank arranged outside the valve body, the valve body is provided with a first cavity connected to the first main hydraulic oil circuit, a second cavity connected to the second main hydraulic oil circuit and an intermediate cavity between the first cavity and the second cavity, the intermediate cavity is provided with the valve core, the middle part of the valve body is provided with a first pipeline connected to the oil storage tank, a second pipeline connected to the oil storage tank The fourth pipeline, the second pipeline connecting the first cavity and the middle cavity, the third pipeline connecting the second cavity and the middle cavity, the inlet of the second pipeline connecting the middle cavity is close to the second cavity, the inlet of the third pipeline connecting the middle cavity is close to the first cavity, the fourth pipeline has two connecting inlets with the middle cavity, one of which is close to the first cavity and the other is close to the second cavity, a one-way valve is provided on the inlet of the second pipeline connecting the first cavity and the inlet of the third pipeline connecting the second cavity, an oil pump is connected in series on the first pipeline, the valve core includes a central stepped shaft whose diameter matches the middle cavity and baffles provided at both ends of the central stepped shaft, and both sides of the central part of the central stepped shaft have reduced diameter sections; during operation, when the lifting heights of the first scissor lift and the second scissor lift are the same, the anti-dumping actuator is not started, and at this time, the interior of the anti-dumping actuator is as follows Figure 2 As shown in FIG. 1 , when the lifting heights of the first scissor lift and the second scissor lift are different, the interior of the anti-dumping actuator is as follows: Figure 3 As shown, the anti-dumping actuator is started to work.

[0034] Furthermore, since the first cavity is connected to the first main hydraulic oil circuit, the first main hydraulic oil circuit flows into the first cavity, and the second cavity is connected to the second main hydraulic oil circuit, the second main hydraulic oil circuit flows into the second cavity. Because the first cavity and the second cavity in the valve body have the same structure, when the oil pressure in the first main hydraulic oil circuit and the second main hydraulic oil circuit are the same, the amount of oil flowing into the first cavity and the second cavity is the same. At this time, the pressure in the first cavity and the second cavity is the same, so that the surface pressure of the two baffles of the valve core is the same, and the valve core is in the middle position and does not move (at this time, the interior of the anti-dumping actuator is as shown in FIG. Figure 2 As shown); When the first or second main hydraulic oil circuit is abnormal, such as when the second main hydraulic oil circuit is blocked, the pressure in the second cavity will be lower than that in the first cavity (at this time, the internal part of the anti-dumping actuator is as shown in FIG. Figure 3 As shown in the figure), the heights of the first scissor lift and the second scissor lift will be inconsistent, the receiver in the photoelectric sensor cannot receive the signal, and the motor signal of the oil pump is given, and the oil pump starts to pump oil; since the valve core can move axially, the valve core will be close to the second cavity. At this time, due to continuous oil pumping, the oil in the oil storage tank is input from the first pipeline to the middle cavity, and the oil cannot enter the right part of the middle cavity and return to the oil storage tank from the third pipeline. At this time, the one-way valve of the second cavity will be pushed open, and the oil will enter the second cavity. Since the second cavity is connected to the second main hydraulic oil circuit, the oil in the second main hydraulic oil circuit can be The pressure continues to rise, the second scissor lift operates normally, the pressure difference between the two chambers is reduced, and as the oil is continuously pumped, the oil in the second chamber can be well compensated; as the oil pressure difference between the first and second chambers slowly decreases, the valve body will slowly slide toward the first chamber, but before the valve core slides to the exact center of the valve body, the oil pressure flowing into the third pipeline will still be greater than the oil pressure of the second pipeline due to the inconsistency between the size of the valve core and the inlet of each pipeline. At this time, more oil will continue to be pumped into the second chamber until the oil pressures of the first and second chambers are the same and the valve core slides to the exact center of the valve body.

[0035] Furthermore, the oil pressures in the first and second cavities are the same, that is, the valve core is located at the center of the valve body (at this time, the interior of the anti-dumping actuator is as follows Figure 2 As shown), however, if the sensor's receiver is blocked by maintenance personnel or other reasons, the oil pump's motor will also be activated, causing the oil pump to pump oil. At this time, since the first and second main hydraulic pipes work normally, the pressures in the first and second cavities are still the same, and the oil enters the middle cavity through the first pipeline from the oil storage tank, and finally flows back to the oil storage tank through the fourth pipeline; although the oil will flow into the second and third pipelines, there are one-way valves for the second and third pipelines to enter the first and second cavities. At this time, since the second and third pipelines are connected to the fourth pipeline, the pressure is too small to open the one-way valve, and finally the oil still flows back to the oil storage tank.

[0036] The hydraulic scissor lift anti-dumping automatic adjustment device of the present invention can automatically adjust the first and second main hydraulic oil circuits, so that the oil pressures in the first cavity and the second cavity are the same, so that the lifting heights of the first scissor lift and the second scissor lift are consistent, reducing the risk of automobile dumping.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. An automatic anti-dumping adjustment device for a hydraulic scissor lift, characterized in that: The invention comprises two sets of scissor lifts and anti-dumping actuators arranged in parallel for jointly lifting a car, wherein the two sets of scissor lifts are respectively a first scissor lift and a second scissor lift, wherein the first scissor lift and the second scissor lift are respectively provided with a first main hydraulic oil circuit and a second main hydraulic oil circuit, wherein the anti-dumping actuator comprises a valve body, a valve core arranged in the valve body and an oil storage tank arranged outside the valve body, wherein the valve body is provided with a first cavity connected to the first main hydraulic oil circuit, a second cavity connected to the second main hydraulic oil circuit and an intermediate cavity between the first cavity and the second cavity, wherein the valve core is arranged in the intermediate cavity, and the middle part of the valve body is provided with a first pipeline connected to the oil storage tank, a fourth pipeline connected to the oil storage tank, a second pipeline connected to the first cavity and the intermediate cavity, and a second pipeline connected to the second cavity. The third pipeline of the cavity and the middle cavity, the inlet of the second pipeline connecting to the middle cavity is close to the second cavity, the inlet of the third pipeline connecting to the middle cavity is close to the first cavity, the fourth pipeline connecting to the middle cavity has two connecting inlets, one of which is close to the first cavity and the other is close to the second cavity, and a one-way valve is provided on the inlet of the second pipeline connecting to the first cavity and the inlet of the third pipeline connecting to the second cavity, an oil pump is connected in series on the first pipeline, the valve core includes a central stepped shaft whose diameter matches the middle cavity and baffles provided at both ends of the central stepped shaft, and both sides of the central part of the central stepped shaft have reduced diameter sections; the fourth pipeline branches into two branches in the valve body, and the connecting inlets of the two branches and the middle cavity have second rectangular recessed grooves; the length of the central stepped shaft is greater than the length of the middle cavity.

2. The anti-dumping automatic adjustment device for a hydraulic scissor lift according to claim 1, characterized in that: The central stepped shaft includes a middle shaft section, reduced diameter sections on both sides of the middle shaft section and an outer shaft section outside the reduced diameter section. The first pipeline has a first rectangular recessed groove at the entrance of the middle cavity, and the width of the middle shaft section is smaller than the width of the rectangular recessed groove.

3. The anti-dumping automatic adjustment device for a hydraulic scissor lift according to claim 1 is characterized in that: The first, second, third and fourth pipelines are not connected.

4. The anti-dumping automatic adjustment device for a hydraulic scissor lift according to claim 1 is characterized in that: Receivers and transmitters of photoelectric sensors are respectively disposed on opposite surfaces of the two lifting plates on the first scissor lift and the second scissor lift. The receivers and transmitters of the photoelectric sensors are electrically connected to a controller, and the controller is electrically connected to a driving motor of an oil pump.

5. A working method of an automatic anti-dumping adjustment device for a hydraulic scissor lift, characterized in that: The hydraulic scissor lift anti-dumping automatic adjustment device comprises two groups of scissor lifts and anti-dumping actuators arranged in parallel for jointly lifting a car, the two groups of scissor lifts are respectively a first scissor lift and a second scissor lift, the first scissor lift and the second scissor lift are respectively provided with a first main hydraulic oil circuit and a second main hydraulic oil circuit, the anti-dumping actuator comprises a valve body, a valve core arranged in the valve body and an oil storage tank arranged outside the valve body, the valve body is provided with a first cavity connected to the first main hydraulic oil circuit, a second cavity connected to the second main hydraulic oil circuit and an intermediate cavity between the first cavity and the second cavity, the intermediate cavity is provided with the valve core, the middle part of the valve body is provided with a first pipeline connected to the oil storage tank, a fourth pipeline connected to the oil storage tank, a second pipeline connected to the first cavity and the intermediate cavity, a second pipeline connected to the first cavity and the intermediate cavity, and a pipeline connected to the first and second cavities. The third pipeline of the second cavity and the middle cavity, the inlet of the second pipeline communicating with the middle cavity is close to the second cavity, the inlet of the third pipeline communicating with the middle cavity is close to the first cavity, the fourth pipeline has two communicating inlets with the middle cavity, one of which is close to the first cavity and the other is close to the second cavity, a one-way valve is provided on the inlet of the second pipeline and the first cavity, and the inlet of the third pipeline and the second cavity, an oil pump is connected in series on the first pipeline, the valve core includes a central stepped shaft whose diameter matches the middle cavity and baffles provided at both ends of the central stepped shaft, and both sides of the central part of the central stepped shaft have reduced diameter sections; during operation, when the lifting heights of the first scissor lift and the second scissor lift are the same, the anti-dumping actuator is not started, and when the lifting heights of the first scissor lift and the second scissor lift are inconsistent, the anti-dumping actuator is started.

6. The working method of the automatic anti-dumping adjustment device for a hydraulic scissor lift according to claim 5, characterized in that: Since the first cavity is connected with the first main hydraulic oil circuit, the first main hydraulic oil circuit flows into the first cavity, and the second cavity is connected with the second main hydraulic oil circuit, the second main hydraulic oil circuit flows into the second cavity. Because the first cavity and the second cavity in the valve body have the same structure, when the oil pressure in the first main hydraulic oil circuit and the second main hydraulic oil circuit are the same, the amount of oil flowing into the first cavity and the second cavity is the same. At this time, the pressures of the first cavity and the second cavity are the same, so that the surface pressures of the two baffles of the valve core are the same, and the valve core is in the middle position and does not move; when the second main hydraulic oil circuit is blocked, the pressure of the second cavity will be lower than that of the first cavity, resulting in the heights of the first scissor lift and the second scissor lift being inconsistent, the receiver in the photoelectric sensor cannot receive the signal, and the motor signal of the oil pump is given, and the oil pump starts to pump oil; since the valve core can move axially, it will cause the valve core to approach the second cavity. At this time, due to the continuous pumping of oil , the oil in the oil storage tank is input into the middle cavity from the first pipeline, and the oil cannot enter the right part of the middle cavity and return to the oil storage tank from the third pipeline. At this time, the one-way valve of the second cavity will be pushed open, and the oil will enter the second cavity. Since the second cavity is connected to the second main hydraulic oil circuit, the oil pressure of the second main hydraulic oil circuit can continue to rise, and the second scissor lift can operate normally. The pressure difference between the two cavities is reduced. With the continuous pumping of oil, the oil in the second cavity can be well compensated; when the oil pressure difference between the first and second cavities is slowly reduced, the valve body will slowly slide toward the first cavity, but before the valve core slides to the center of the valve body, due to the inconsistency between the size of the valve core and the inlet of each pipeline, the oil pressure flowing into the third pipeline will still be greater than the oil pressure of the second pipeline. At this time, more oil will continue to be pumped into the second cavity until the oil pressure of the first and second cavities is the same and the valve core slides to the center of the valve body.

7. The working method of the automatic anti-dumping adjustment device for a hydraulic scissor lift according to claim 5, characterized in that: The oil pressure in the first and second cavities is the same, that is, the valve core is located in the center of the valve body, but the sensor's receiver is blocked by maintenance personnel or other reasons. At this time, the oil pump's motor will also be activated, so that the oil pump can pump oil. At this time, since the first and second main hydraulic pipes work normally, the pressure in the first and second cavities is still the same, and the oil enters the middle cavity through the first pipeline from the oil storage tank, and finally flows back to the oil storage tank through the fourth pipeline; although the oil will flow into the second and third pipelines, the second and third pipelines entering the first and second cavities have one-way valves. At this time, since the second and third pipelines are connected to the fourth pipeline, the pressure is too small to open the one-way valve, and finally the oil still flows back to the oil storage tank.

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