Hydraulic lifting platform and film production line

Abstract

The application provides a hydraulic lifting platform and a film production line, which comprises a platform, two lifting cylinders for driving the platform to lift, an oil pump, an oil supply oil path and an oil return oil path connected with the oil pump, a synchronous motor communicated with the oil supply oil path, a rodless cavity of each of the two lifting cylinders communicated with one of two output ends of the synchronous motor, a rod cavity of each of the two lifting cylinders communicated with the oil return oil path, an oil supplement oil path connected with the rodless cavity of each of the two lifting cylinders, the oil supplement oil path connected with the oil pump, a first switch control valve arranged in the oil supply oil path, and a second switch control valve arranged in the oil supplement oil path. In the technical scheme, the oil supplement oil path is connected with the two lifting cylinders one by one, so that when the two lifting cylinders lift with deviation under the action of the synchronous motor, the two oil supplement oil paths can be adjusted, the flatness of the platform during lifting is improved, and the supporting effect on the film is improved.

Description

Technical Field

[0001] This application relates to the field of film technology, and in particular to a hydraulic lifting platform and a film production line. Background Technology

[0002] In the mixing process of rubber tire and product factories, the rubber sheet cooling line is used to impregnate, air-dry, cool, and stack the rubber sheets before transferring them to subsequent processes. The rubber sheet stacking structure requires a lifting mechanism capable of rapidly raising the sheet 1.5 meters within 5 seconds, while simultaneously requiring a 30mm inching descent every 5 seconds. The current dual-cylinder hydraulic lifting method suffers from asynchrony between the left and right sides, causing the platform to tilt during lifting. This poses a safety hazard, potentially damaging equipment, and excessive deviation results in poor stacking neatness, affecting stable equipment operation. Summary of the Invention

[0003] The purpose of this utility model application is to provide a hydraulic lifting platform and a film production line to improve the support effect on the film.

[0004] This application provides a hydraulic lifting platform, which includes: a platform, and lifting cylinders connected to the platform and used to drive the platform to lift; the number of lifting cylinders is two, and they are arranged on both sides of the platform. It also includes an oil pump, an oil supply circuit and an oil return circuit connected to the oil pump, and a synchronous motor connected to the oil supply circuit; the rodless chambers of the two lifting cylinders are connected to the two output ends of the synchronous motor in a one-to-one correspondence; the rod chambers of the two lifting cylinders are respectively connected to the oil return circuit. It also includes a replenishing oil circuit that corresponds one-to-one with the rodless chamber of each lifting cylinder; the replenishing oil circuit is connected to the oil pump; It also includes a first switch control valve installed in the oil supply circuit and a second switch control valve installed in the oil replenishment circuit.

[0005] In the above technical solution, the oil replenishment circuit is connected to the two lifting cylinders one by one. When the two lifting cylinders deviate from their lifting position under the action of the synchronous motor, the two oil replenishment circuits can be used for adjustment, thereby improving the flatness of the platform during lifting and thus improving the support effect on the film.

[0006] In one specific implementation scheme, the oil supply circuit includes a first oil supply branch and a second oil supply branch connected in parallel; the first switch control valve includes a first control sub-switch and a second control sub-switch; wherein the first control sub-switch is located in the first oil supply branch, and the second control sub-switch is located in the second oil supply branch; wherein the oil supply volume of the first oil supply branch is greater than the oil supply volume of the second oil supply branch.

[0007] In one specific implementation scheme, the return oil circuit includes a first return oil branch and a second return oil branch connected in parallel; Both the first control sub-switch and the second control sub-switch are three-position four-way switch control valves; When the first control sub-switch is in the first state, the first oil supply branch is connected to the oil pump, and the first oil return branch is connected to the oil tank; when the first control sub-switch is in the second state, the first oil supply branch is connected to the oil tank, and the first oil return branch is connected to the oil pump; when the first control sub-switch is in the third state, the first oil supply branch is disconnected from the oil pump, and the first oil return branch is disconnected from the oil tank. When the second control sub-switch is in the first state, the second oil supply branch is connected to the oil pump, and the second oil return branch is connected to the oil tank; when the second control sub-switch is in the second state, the second oil supply branch is connected to the oil tank, and the second oil return branch is connected to the oil pump.

[0008] In one specific implementation scheme, a speed control valve is also provided on the second oil supply branch.

[0009] In one specific implementation scheme, the two oil replenishment circuits are a first oil replenishment circuit and a second oil replenishment circuit; The second switch control valve is a three-position four-way switch control valve; When the second switch control valve is in the first state, the first replenishing oil circuit is connected to the oil pump, and the second replenishing oil circuit is connected to the oil tank; when the second switch control valve is in the second state, the first replenishing oil circuit is connected to the oil tank, and the second replenishing oil circuit is connected to the oil pump; when the second switch control valve is in the third state, the first replenishing oil circuit and the second replenishing oil circuit are connected to the oil tank.

[0010] In one specific feasible implementation, it also includes a first hydraulically controlled check valve disposed in the first replenishment oil circuit and a second hydraulically controlled check valve disposed in the second replenishment oil circuit; The hydraulic control end of the first hydraulic check valve is connected to the second oil replenishment circuit; the hydraulic control end of the second hydraulic check valve is connected to the first oil replenishment circuit.

[0011] In one specific feasible implementation, it also includes one-way throttle valves disposed in the first replenishing oil circuit and the second replenishing oil circuit.

[0012] In one specific implementation scheme, a position sensor is also included, which is installed on the pistons of the two lifting cylinders in a one-to-one correspondence. It also includes a controller for controlling the state of the second switch control valve based on the comparison results of the two sensors.

[0013] In one specific implementation scheme, an electromagnetic relief valve is also provided in the oil supply circuit and the oil return circuit.

[0014] In a second aspect, a film production line is provided, which includes the hydraulic lifting platform described in any of the above claims.

[0015] In the above technical solution, the oil replenishment circuit is connected to the two lifting cylinders one by one. When the two lifting cylinders deviate from their lifting position under the action of the synchronous motor, the two oil replenishment circuits can be used for adjustment, thereby improving the flatness of the platform during lifting and thus improving the support effect on the film. Attached Figure Description

[0016] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments provided according to this disclosure and should not be construed as limiting the scope of this disclosure.

[0017] Figure 1 This is a schematic diagram of the structure of the hydraulic lifting platform provided in the embodiments of this application; Figure 2 A schematic diagram of a hydraulic system provided for an embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0019] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of this specification should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar words used in one or more embodiments of this specification do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0020] To facilitate understanding of the hydraulic lifting platform provided in this application embodiment, its application scenario is first described. The hydraulic lifting platform provided in this application embodiment is applied in the scenario of film stacking. Currently, when stacking films, the platform is prone to left-right asynchrony during lifting, resulting in tilting. Therefore, this application embodiment provides a hydraulic lifting platform to improve the lifting effect of the platform, thereby improving the support effect on the film. A detailed description follows with reference to specific drawings and embodiments.

[0021] refer to Figure 1 As shown, Figure 1 A schematic diagram of the structure of the hydraulic lifting platform provided in this application embodiment is shown. The hydraulic lifting platform provided in this application embodiment mainly includes a platform 100, two lifting cylinders connected to the platform 100, and a hydraulic system for driving the lifting cylinders to extend and retract.

[0022] The platform 100 is supported by a support frame 200, and the lifting cylinder is also supported by the support frame 200. In its specific arrangement, the platform 100 slides relative to the support frame 200 to achieve lifting and lowering. The cylinder body of the lifting cylinder is fixed to the support frame 200, and the piston rod of the lifting cylinder is fixedly connected to the platform 100. There are two lifting cylinders, located on both sides of the platform 100, used to drive the platform 100 to lift and lower.

[0023] Please refer to the above. Figure 2 , Figure 2 A schematic diagram of a hydraulic system provided in an embodiment of this application is shown. The hydraulic system provided in this embodiment includes an oil pump 150, an oil supply circuit 10, and an oil return circuit 20 connected to the oil pump 150. The oil supply circuit 10 is connected to a synchronous motor 190. The two output terminals of the synchronous motor 190 are respectively connected to the rodless chambers of two lifting cylinders, while the rod chambers of the lifting cylinders are connected to the oil return circuit 20. When the platform 100 rises, oil is supplied by the oil pump 150, and the synchronous motor 190 synchronously supplies oil to the rodless chambers of the two lifting cylinders, causing the piston rods of the lifting cylinders to extend and push the platform 100 upwards. When the platform 100 descends, the oil pump 150 stops working, and the oil in the oil tank 160 enters the rod chamber of the lifting cylinder through the oil return circuit 20. The oil in the rodless chamber of the lifting cylinder synchronously flows back to the oil supply circuit 10 via the synchronous motor 190, and then back to the oil tank 160.

[0024] In addition, the hydraulic system includes a replenishing oil circuit that corresponds one-to-one with the rodless chamber of each lifting cylinder; wherein the replenishing oil circuit is connected to the oil pump 150. For ease of description, the two lifting cylinders are named the first lifting cylinder 300 and the second lifting cylinder 400, respectively, and the two replenishing oil circuits are named the first replenishing oil circuit 30 and the second replenishing oil circuit 40, respectively. The rodless chamber of the first lifting cylinder 300 is connected to the first replenishing oil circuit 30, and the rodless chamber of the second lifting cylinder 400 is connected to the second replenishing oil circuit 40.

[0025] When platform 100 rises, if the piston rod height of the first lifting cylinder 300 is less than the piston rod height of the second lifting cylinder 400, oil can be replenished to the rodless chamber of the first lifting cylinder 300 through the first oil replenishment circuit 30, and oil can be drained from the rodless chamber of the second lifting cylinder 400 through the first oil replenishment circuit 30, so that the rising height of the piston rods of the first lifting cylinder 300 and the second lifting cylinder 400 is consistent. Similarly, when platform 100 descends, if the piston rod height of the first lifting cylinder 300 is less than the piston rod height of the second lifting cylinder 400, oil can be replenished to the rodless chamber of the first lifting cylinder 300 through the first oil replenishment circuit 30, and oil can be drained from the rodless chamber of the second lifting cylinder 400 through the second oil replenishment circuit 40, so that the descending height of the piston rods of the first lifting cylinder 300 and the second lifting cylinder 400 is consistent.

[0026] In addition, the hydraulic system also includes a first switch control valve 110 disposed in the oil supply circuit 10 to control the on / off state of the oil supply circuit 10. It also includes a second switch control valve 120 disposed in the replenishment oil circuit to control the on / off state of the replenishment oil circuit.

[0027] As can be seen from the above description, the hydraulic lifting platform 100 provided in this application embodiment can be connected to the two lifting cylinders one-to-one through the set oil replenishment circuit. When the two lifting cylinders deviate from their lifting position under the action of the synchronous motor 190, the two oil replenishment circuits can be used for adjustment, thereby improving the flatness of the platform 100 during lifting and thus improving the support effect on the film.

[0028] Continue to refer to Figure 2As shown, the oil supply circuit 10 provided in this embodiment includes a first oil supply branch 11 and a second oil supply branch 12 connected in parallel. Additionally, the corresponding first switch control valve 110 includes a first control sub-switch 111 and a second control sub-switch 112. In specific configurations, the two control sub-switches correspond one-to-one with the two oil supply branches. For example, the first control sub-switch 111 is located in the first oil supply branch 11, and the second control sub-switch 112 is located in the second oil supply branch 12. When two oil supply branches are specifically configured, the oil supply volume of the first oil supply branch 11 is greater than that of the second oil supply branch 12. With this arrangement, oil can be supplied to the lifting cylinder through the two oil supply branches respectively, thereby allowing the lifting cylinder to have at least two different lifting speeds. For example, when the first oil supply branch 11 is connected to the synchronous motor 190, the lifting cylinder can lift at a higher speed. When the second oil supply branch 12 is connected to the synchronous motor 190, the lifting cylinder can lift at a lower speed.

[0029] Continue to refer to Figure 2 As shown, the return oil circuit 20 provided in this embodiment includes two branches, namely a first return oil branch 21 and a second return oil branch 22, wherein the first return oil branch 21 and the second return oil branch 22 are connected in parallel. When arranging the first control sub-switch 111 and the second control sub-switch 112, the first control sub-switch 111 and the second control sub-switch 112 are also connected to the first return oil branch 21 and the second return oil branch 22, respectively. In the above-described manner, both the first control sub-switch 111 and the second control sub-switch 112 employ three-position four-way switch control valves. Taking the first control sub-switch 111 as an example, its four connection ports are respectively connected to the oil pump 150, the oil tank 160, the first oil supply branch 11, and the first return oil circuit 20. Similarly, the four connection ports of the second control sub-switch 112 are respectively connected to the oil pump 150, the oil tank 160, the second oil supply branch 12, and the second return oil branch 22.

[0030] In specific control operations, when the first control sub-switch 111 is in the first state, the first oil supply branch 11 is connected to the oil pump 150, and the first oil return branch 21 is connected to the oil tank 160. At this time, the oil pump 150 can pump oil into the synchronous motor 190 through the first oil supply branch 11, and the oil in the rodless chambers of the first lifting cylinder 300 and the second lifting cylinder 400 flows back to the oil tank 160 through the first oil return branch 21. When the first control sub-switch 111 is in the second state, the first oil supply branch 11 is connected to the oil tank 160, and the first oil return branch 21 is connected to the oil pump 150. At this time, the oil pump 150 can pump oil into the rodless chambers of the first lifting cylinder 300 and the second lifting cylinder 400 through the first oil return branch 21, and the oil in the rod chambers of the first lifting cylinder 300 and the second lifting cylinder 400 flows back to the oil tank 160 through the first oil supply branch 11. When the first control sub-switch 111 is in the third state, the first oil supply branch 11 is disconnected from the oil pump 150, and the first oil return branch 21 is disconnected from the oil tank 160. At this time, the oil pump 150 and the oil tank 160 are disconnected from the two lifting cylinders, and the piston rods of the two lifting cylinders can be held in their positions, thereby locking the platform 100.

[0031] Similarly, when the second control sub-switch 112 is in the first state, the second oil supply branch 12 is connected to the oil pump 150, and the second oil return branch 22 is connected to the oil tank 160; when the second control sub-switch 112 is in the second state, the second oil supply branch 12 is connected to the oil tank 160, and the second oil return branch 22 is connected to the oil pump 150. The control logic of the second control sub-switch 112 is the same as that of the first control sub-switch 111, and will not be described again here.

[0032] In an optional embodiment, the hydraulic system provided in this application further includes a speed regulating valve 180 disposed on the second oil supply branch 12. The speed regulating valve 180 is used to adjust the flow rate of the oil in the second oil supply branch 12. When the above-mentioned speed regulating valve is used, the flow rate of the oil in the second oil supply branch 12 can be adjusted as needed, thereby controlling the lifting speed of the first lifting cylinder 300 and the second lifting cylinder 400.

[0033] For ease of description, the two replenishing oil circuits are designated as the first replenishing oil circuit 30 and the second replenishing oil circuit 40. In an optional configuration, the second switch control valve 120 is a three-position four-way switch control valve. The four connection ports of the second switch control valve 120 are respectively connected to the first replenishing oil circuit 30, the second replenishing oil circuit 40, the oil pump 150, and the oil tank 160. When the second switch control valve 120 is in control, it has three different states. The specific states are as follows: When the second switch control valve 120 is in the first state, the first oil replenishment circuit 30 is connected to the oil pump 150, and the second oil replenishment circuit is connected to the oil tank 160. In this mode, the oil pump 150 replenishes oil to the first lifting cylinder 300 through the first oil replenishment circuit 30. Simultaneously, the oil supplied to the second lifting cylinder 400 can flow back to the oil tank 160 through the second oil replenishment circuit 40. This oil replenishment method corresponds to a situation where the lifting speed of the first lifting cylinder 300 is slower, while the lifting speed of the second lifting cylinder 400 is faster.

[0034] When the second switch control valve 120 is in the second state, the first oil replenishment circuit 30 is connected to the oil tank 160, and the second oil replenishment circuit 40 is connected to the oil pump 150. In this mode, the oil pump 150 replenishes oil to the second lifting cylinder 400 through the second oil replenishment circuit 40. Simultaneously, the oil supplied to the first lifting cylinder 300 can flow back to the oil tank 160 through the second oil replenishment circuit 40. This oil replenishment method corresponds to a situation where the lifting speed of the second lifting cylinder 400 is slower, while the lifting speed of the first lifting cylinder 300 is faster.

[0035] Similarly, during descent, when the height of the piston rod of the first lifting cylinder 300 is less than the height of the piston rod of the second lifting cylinder 400, oil can be replenished to the rodless chamber of the first lifting cylinder 300 through the first oil replenishment circuit 30, and oil can be drained from the rodless chamber of the second lifting cylinder 400 through the second oil replenishment circuit 40, so that the descent height of the piston rods of the first lifting cylinder 300 and the second lifting cylinder 400 is consistent.

[0036] When the second switch control valve 120 is in the third state, the first oil replenishment circuit 30 and the second oil replenishment circuit 40 are connected to the oil tank 160. In this manner, the oil can be drained through the first oil replenishment circuit 30 and the second oil replenishment circuit 40 in conjunction with the rodless chamber, allowing the platform 100 to descend rapidly.

[0037] Continue to refer to Figure 2 The hydraulic system provided in this application embodiment further includes a first hydraulically controlled check valve 130 disposed in the first replenishment oil circuit 30 and a second hydraulically controlled check valve 140 disposed in the second replenishment oil circuit 40. The hydraulically controlled end of the first hydraulically controlled check valve 130 is connected to the second replenishment oil circuit 40; the hydraulically controlled end of the second hydraulically controlled check valve 140 is connected to the first replenishment oil circuit 30. The two second hydraulically controlled check valves 140 can control the flow direction of the oil in the corresponding replenishment oil circuit. For example, when oil flows in the first replenishment oil circuit 30, the second hydraulically controlled check valve 140 is opened, allowing bidirectional oil flow. When no oil flows in the first replenishment oil circuit 30, the second hydraulically controlled check valve 140 is closed, allowing unidirectional oil flow.

[0038] In an optional embodiment, the hydraulic system further includes one-way throttle valves installed in the first replenishing oil circuit 30 and the second replenishing oil circuit 40. These one-way throttle valves in the first and second replenishing oil circuits 30 and 40 can adjust the oil flow rate in these circuits, thereby adjusting the replenishment speed to the first lifting cylinder 300 and the second lifting cylinder 400.

[0039] In an optional embodiment, the hydraulic system further includes position sensors corresponding to the pistons of the two lifting cylinders, which are used to detect the positions of the two lifting cylinders. Additionally, the hydraulic lifting platform 100 includes a controller, which controls the state of the second switching control valve 120 based on the comparison results of the two sensors. Specifically, the controller controls the second switching control valve 120 to replenish oil when the difference in positions detected by the two position sensors exceeds a set value. The specific state of the second switching control valve 120 is described above. Its control logic follows this pattern: when the platform 100 rises, oil is replenished for the slower rising speed and released for the faster rising speed. When the platform 100 descends, oil is released for the slower descending speed and replenished for the faster descending speed. It should be understood that the controller provided in this embodiment controls the switching of the second switching control valve 120 based on the position sensor detection results, which is conventional control logic. The hydraulic lifting platform 100 provided in this embodiment only achieves automatic adjustment of the balance of the platform 100 during rising and falling through the cooperation of the controller and position sensors.

[0040] In an optional embodiment, the hydraulic system provided by this application further includes an electromagnetic relief valve 170 disposed in the oil supply line 10 and the oil return line 20. This electromagnetic relief valve 170 serves as a safety valve to ensure that the entire hydraulic system remains within a safe oil pressure range.

[0041] It should be understood that the hydraulic system provided in this application embodiment also includes some common valves in conventional hydraulic systems such as check valves, pressure gauges, coolers, and filters to ensure the safety of the hydraulic system, which will not be described in detail here.

[0042] This application also provides a film production line, which includes the hydraulic lifting platform 100 of any of the above claims.

[0043] In the above technical solution, the oil replenishment circuit is connected to the two lifting cylinders one by one. When the two lifting cylinders deviate from their lifting position under the action of the synchronous motor 190, the two oil replenishment circuits can be used for adjustment, thereby improving the flatness of the platform 100 during lifting and thus improving the support effect on the film.

[0044] One or more embodiments of this specification are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this specification should be included within the scope of protection of this disclosure.

[0045] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A hydraulic lifting platform, characterized in that, include: A platform, and lifting cylinders connected to the platform and used to drive the platform to rise and fall; there are two lifting cylinders, which are arranged on both sides of the platform; It also includes an oil pump, an oil supply circuit and an oil return circuit connected to the oil pump, and a synchronous motor connected to the oil supply circuit; the rodless chambers of the two lifting cylinders are connected to the two output ends of the synchronous motor in a one-to-one correspondence; the rod chambers of the two lifting cylinders are respectively connected to the oil return circuit. It also includes a replenishing oil circuit that corresponds one-to-one with the rodless chamber of each lifting cylinder; the replenishing oil circuit is connected to the oil pump; It also includes a first switch control valve installed in the oil supply circuit and a second switch control valve installed in the oil replenishment circuit.

2. The hydraulic lifting platform according to claim 1, characterized in that, The oil supply circuit includes a first oil supply branch and a second oil supply branch connected in parallel; the first switch control valve includes a first control sub-switch and a second control sub-switch; wherein the first control sub-switch is located in the first oil supply branch, and the second control sub-switch is located in the second oil supply branch; wherein the oil supply volume of the first oil supply branch is greater than the oil supply volume of the second oil supply branch.

3. The hydraulic lifting platform according to claim 2, characterized in that, The return oil circuit includes a first return oil branch and a second return oil branch connected in parallel; Both the first control sub-switch and the second control sub-switch are three-position four-way switch control valves; When the first control sub-switch is in the first state, the first oil supply branch is connected to the oil pump, and the first oil return branch is connected to the oil tank; when the first control sub-switch is in the second state, the first oil supply branch is connected to the oil tank, and the first oil return branch is connected to the oil pump; when the first control sub-switch is in the third state, the first oil supply branch is disconnected from the oil pump, and the first oil return branch is disconnected from the oil tank. When the second control sub-switch is in the first state, the second oil supply branch is connected to the oil pump, and the second oil return branch is connected to the oil tank; when the second control sub-switch is in the second state, the second oil supply branch is connected to the oil tank, and the second oil return branch is connected to the oil pump.

4. The hydraulic lifting platform according to claim 3, characterized in that, It also includes a speed control valve installed on the second oil supply branch.

5. The hydraulic lifting platform according to claim 1, characterized in that, The two oil replenishment circuits are the first oil replenishment circuit and the second oil replenishment circuit; The second switch control valve is a three-position four-way switch control valve; When the second switch control valve is in the first state, the first replenishing oil circuit is connected to the oil pump, and the second replenishing oil circuit is connected to the oil tank; when the second switch control valve is in the second state, the first replenishing oil circuit is connected to the oil tank, and the second replenishing oil circuit is connected to the oil pump; when the second switch control valve is in the third state, the first replenishing oil circuit and the second replenishing oil circuit are connected to the oil tank.

6. The hydraulic lifting platform according to claim 5, characterized in that, It also includes a first hydraulically controlled check valve installed in the first oil replenishment circuit and a second hydraulically controlled check valve installed in the second oil replenishment circuit; The hydraulic control end of the first hydraulic check valve is connected to the second oil replenishment circuit; the hydraulic control end of the second hydraulic check valve is connected to the first oil replenishment circuit.

7. The hydraulic lifting platform according to claim 6, characterized in that, It also includes one-way throttle valves installed in the first oil replenishment circuit and the second oil replenishment circuit.

8. The hydraulic lifting platform according to claim 1, characterized in that, It also includes position sensors that are installed one-to-one on the pistons of the two lifting cylinders; It also includes a controller for controlling the state of the second switch control valve based on the comparison results of the two sensors.

9. The hydraulic lifting platform according to any one of claims 1 to 8, characterized in that, It also includes electromagnetic relief valves installed in the oil supply circuit and the oil return circuit.

10. A film production line, characterized in that, Including the hydraulic lifting platform as described in any one of claims 1 to 9.

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