A safe forklift valve control system

Abstract

The application provides a safe forklift valve control system, which comprises a multi-way valve, a descending electromagnetic valve connected in series on a descending control oil channel of the multi-way valve, an oil inlet electromagnetic valve connected in series on an oil return channel of the multi-way valve, and power supply ends of the descending electromagnetic valve and the oil inlet electromagnetic valve are electrically connected with a pressure switch installed on a seat through a relay, and the on-off of the oil paths of the descending electromagnetic valve and the oil inlet electromagnetic valve is controlled through the switch of the pressure switch. The application controls the on-off of the descending electromagnetic valve and the oil inlet electromagnetic valve in the multi-way valve through the pressure switch installed on the seat to realize the operation of the forklift, and significantly improves the safety of the operation, because once the driver leaves the seat or the sitting posture is incorrect, the corresponding valve control rod, the gantry and the accessory cannot be actuated.

Description

Technical Field

[0001] This invention relates to the field of forklift technology, and more specifically to a safe forklift valve control system. Background Technology

[0002] The forklift valve control system is used to control the lifting, tilting, and movement of the mast and various attachments. In other words, the forklift driver controls the lifting, side-shifting, and tilting actions of the forklift by operating the handles on the multi-way valve control mechanism. Currently, in the operating device of the forklift multi-way valve, one handle corresponds to one valve plate in the multi-way valve. Generally, a lifting control lever is used to control the lifting cylinder to achieve the lifting action of the mast, and a tilt control lever is used to control the tilt cylinder to achieve the tilting action of the mast.

[0003] However, most forklifts currently operate as long as the corresponding valve lever is operated, the mast and attachments can move. They do not pay attention to whether the driver leaves the seat or sits incorrectly in the seat. If this happens, it will pose a safety problem to the driver, surrounding personnel and the environment.

[0004] To address this problem, the present invention designs a control method that can automatically detect whether the driver has left the seat or is sitting in the driver's seat in the correct posture. Once the driver leaves the seat or is in an incorrect posture, the corresponding valve lever will not be operated, and the mast and attachments will not move. Summary of the Invention

[0005] The purpose of this invention is to provide a safe forklift valve control system that effectively ensures that the driver can operate the mast and attachments while seated in the correct posture, thus avoiding any safety issues for the driver, surrounding personnel, and the environment.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A safe forklift valve control system includes a multi-way valve. A descent solenoid valve is connected in series on the descent control oil passage of the multi-way valve, and an inlet solenoid valve is connected in series on the return oil passage of the multi-way valve. The power supply terminals of the descent solenoid valve and the inlet solenoid valve are electrically connected to a pressure switch installed on the seat via a relay. The opening and closing of the oil passages of the descent solenoid valve and the inlet solenoid valve are controlled by switching the pressure switch on and off.

[0008] In a further embodiment, the multi-way valve includes a flow divider valve connected to the oil pump outlet. One outlet of the flow divider valve is connected to the steering cylinder via a steering gear, and the other outlet of the flow divider valve is connected to a lifting directional valve, a tilting directional valve, and a hydraulically controlled spool valve, respectively.

[0009] The two working ports of the lifting and reversing valve are respectively connected to the hydraulic control check valve and the lowering solenoid valve.

[0010] The working port of the tilting reversing valve is connected to the tilting cylinder; the hydraulic control slide valve is connected to the oil inlet solenoid valve, and the return ports of both the hydraulic control slide valve and the oil inlet solenoid valve are connected to the oil tank.

[0011] In a further embodiment, one end of the descent solenoid valve is connected to the working port of the lifting directional valve via a first descent control oil passage, and the other end is connected to the lifting cylinder via a second descent control oil passage and a ring oil passage; the hydraulic control check valve is connected in series between the lifting directional valve and the lifting cylinder of the multi-way valve.

[0012] In a further embodiment, one end of the oil inlet solenoid valve is connected to the annular oil passage through the second unloading oil passage, and the other end is connected to the control valve. The return port of the control valve is connected to the oil tank through the annular oil passage.

[0013] In a further embodiment, a first check valve is connected in series between the flow divider valve and the tilting directional valve.

[0014] In a further embodiment, a speed limiting valve and a shut-off valve are connected between the lifting cylinder and the multi-way valve; an oil suction filter is connected to the oil inlet of the oil pump, and an oil return filter is connected to the oil return port of the multi-way valve.

[0015] In a further embodiment, the return ports of the lifting directional valve and the tilting directional valve are connected to the oil tank sequentially through the return oil passage and the annular oil passage.

[0016] In a further embodiment, the lowering solenoid valve is normally open and the oil inlet solenoid valve is normally closed. When the pressure switch is connected to the circuit, the lowering solenoid valve is energized to open the oil circuit, and the oil inlet solenoid valve is energized to close the oil circuit.

[0017] In a further embodiment, a lifting control lever is installed on the lifting directional valve, and a tilting control lever is installed on the tilting directional valve. The lifting control lever controls the opening and closing of the oil circuit of the lifting directional valve, and the tilting control lever controls the opening and closing of the oil circuit of the tilting directional valve.

[0018] The multi-way valve and multi-way valve control system in this application are mounted on the vehicle frame. The lifting control lever and tilt control lever both have high, medium and low positions. By operating the high, medium and low positions of the lifting control lever and tilt control lever, the operation of the multi-way valve lifting directional valve and tilt directional valve can be manually controlled.

[0019] The pressure switch in this application is installed on the seat and connected in series with the vehicle's power supply. It detects whether the driver is sitting correctly in the seat. When the driver is sitting correctly, the pressure switch closes. The coil of the relay is connected to the pressure switch. When energized, its contacts close, energizing both the lowering solenoid valve and the oil inlet solenoid valve connected to the relay contacts. Since the lowering solenoid valve is normally open and the oil inlet solenoid valve is normally closed, when the pressure switch connects the circuit, the lowering solenoid valve is energized and opens the oil circuit, while the oil inlet solenoid valve is energized and closes the oil circuit. The lowering solenoid valve and the oil inlet solenoid valve are connected in series in the lowering control oil passage and the unloading oil passage of the multi-way valve, respectively. The energization and de-energization of the lowering solenoid valve controls the opening and closing of the mast lowering oil circuit, and the energization and de-energization of the oil inlet solenoid valve controls the opening and closing of the mast lifting oil circuit, the mast tilting oil circuit, and the attachment actuation oil circuit.

[0020] Working principle:

[0021] When the driver is properly seated, the pressure switch closes, energizing both the descent solenoid valve and the oil inlet solenoid valve in the multi-way valve. If the driver operates the lift and tilt levers in the multi-way valve to the high and low positions respectively, the mast will rise, fall, and tilt forward and backward, thus actuating the attachments. If the driver does not operate the lift and tilt levers in the multi-way valve control system and leaves them in the neutral position, the mast will remain stationary, and the attachments will not move.

[0022] When the driver is not sitting in the seat or in an incorrect posture, the pressure switch will disconnect, and the descent solenoid valve and oil inlet solenoid valve in the multi-way valve will lose power. No matter how the driver operates the lifting control lever and tilt control lever in the multi-way valve control system in the high, medium, or low positions, the mast will remain stationary and the attachments will not move.

[0023] This application controls the operation of the forklift by installing a pressure switch on the seat to control the opening and closing of the descending solenoid valve and the oil inlet solenoid valve in the multi-way valve. This significantly improves the safety of operation because once the driver leaves the seat or is in an incorrect sitting posture, the mast and attachments will not move when the corresponding valve lever is operated.

[0024] Therefore, the valve control system of this application can effectively ensure that the driver can operate the mast and attachments only when the driver is sitting in the seat and in the correct posture. It effectively ensures that the forklift mast and attachments will not move if the driver is not in the seat or if the driver misoperates the system, thus avoiding any safety issues for the driver, surrounding personnel, and the environment. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the oil circuit in this application.

[0026] In the diagram: 1. Oil pump 2. Steering gear 3. Steering cylinder 4. Speed ​​limiter valve 5. Lifting cylinder 6. Shut-off valve 7. Tilting cylinder 8. Multi-way valve 8.1 Ring oil passage 8.2 Hydraulic control spool valve 8.3 Inlet solenoid valve 8.4 First unloading oil passage 8.5 Return oil passage 8.6 Tilting directional valve 8.7 First check valve 8.8 Descending solenoid valve 8.9 Hydraulic control check valve 8.10 First descending control oil passage 8.11 Lifting directional valve 8.12 Second check valve 8.13 Steering relief valve 8.14 Main safety valve 8.15 Diverter valve 8.16 Second descending control oil passage 8.17 Second unloading oil passage 9. Return oil filter 10. Return oil tank 11. Suction oil filter. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] like Figure 1 As shown, a safe forklift valve control system includes a multi-way valve 8. A descent solenoid valve 8.8 is connected in series on the descent control oil passage of the multi-way valve 8, and an inlet solenoid valve 8.3 is connected in series on the return oil passage 8.5 of the multi-way valve 8. The power supply terminals of the descent solenoid valve 8.8 and the inlet solenoid valve 8.3 are electrically connected to a pressure switch installed on the seat via a relay. The opening and closing of the oil passages of the descent solenoid valve 8.8 and the inlet solenoid valve 8.3 are controlled by switching the pressure switch on and off.

[0029] In this application, the pressure switch is connected in series with the vehicle's power supply. The relay coil is connected to the pressure switch, and its contacts are connected to the descent solenoid valve and the oil inlet solenoid valve, respectively, thus forming a circuit. This application installs the pressure switch on the seat, which can detect whether the driver is sitting correctly. When the driver is correctly seated, the pressure switch closes, energizing the relay coil and closing its contacts, thus energizing both the descent and oil inlet solenoid valves. Since the descent solenoid valve is normally open and the oil inlet solenoid valve is normally closed, when the pressure switch connects the circuit, the descent solenoid valve is energized and opens the oil circuit, while the oil inlet solenoid valve is energized and closes the oil circuit. The descent and oil inlet solenoid valves are connected in series in the descent control oil passage and the unloading oil passage of the multi-way valve, respectively. The energization and de-energization of the descent solenoid valve controls the opening and closing of the mast descent oil circuit, and the energization and de-energization of the oil inlet solenoid valve controls the opening and closing of the mast lifting oil circuit, the mast tilting oil circuit, and the attachment actuation oil circuit.

[0030] In addition, a lifting control lever is installed on the lifting directional valve 8.11, and a tilting control lever is installed on the tilting directional valve 8.6. The lifting control lever controls the opening and closing of the oil circuit of the lifting directional valve, and the tilting control lever controls the opening and closing of the oil circuit of the tilting directional valve.

[0031] In a further embodiment, the multi-way valve 8 includes a diverter valve 8.15 connected to the oil outlet of the oil pump 1. The oil pump 1 is driven by a motor to deliver oil. One outlet of the diverter valve 8.15 is connected to the steering cylinder 3 via the steering gear 2. The other outlet of the diverter valve 8.15 is connected to the lifting directional valve 8.11, the tilting directional valve 8.6, and the hydraulic control spool valve 8.2, respectively. The return ports of the lifting directional valve 8.11 and the tilting directional valve 8.6 are connected to the oil tank 10 in sequence via the return oil passage 8.5 and the annular oil passage 8.1 to form a hydraulic oil circuit.

[0032] The two working ports of the lifting directional valve 8.11 are respectively connected to the hydraulic control check valve 8.9 and the lowering solenoid valve 8.8; specifically, one end of the lowering solenoid valve 8.8 is connected to the working port of the lifting directional valve 8.11 through the first lowering control oil passage 8.10, and the other end is connected to the lifting cylinder 5 through the second lowering control oil passage 8.16 and the ring oil passage 8.1; the hydraulic control check valve 8.9 is connected in series between the lifting directional valve 8.11 and the lifting cylinder 5 of the multi-way valve.

[0033] The working port of the tilting directional valve 8.6 is connected to the tilting cylinder 7; the hydraulically controlled spool valve 8.2 is connected to the inlet solenoid valve 8.3, and the return ports of both the hydraulically controlled spool valve 8.2 and the inlet solenoid valve 8.3 are connected to the oil tank 10. Specifically, one end of the inlet solenoid valve 8.3 is connected to the annular oil passage 8.1 through the unloading oil passage 8.17, and the other end is connected to the spool valve 8.2. The return port of the spool valve 8.2 is connected to the oil tank 10 through the annular oil passage 8.1 for oil return.

[0034] In a further embodiment, a first check valve 8.7 is connected in series between the flow divider valve 8.15 and the tilt directional valve 8.6, and a second check valve 8.12 is also connected in series between the flow divider valve 8.15 and the steering gear 2. The check valves are designed to restrict the flow of hydraulic oil. A steering relief valve 8.13 is connected between the outlet of the second check valve 8.12 and the return oil passage 8.5, and a main safety valve 8.14 is connected between the inlet of the flow divider valve 8.15 and the return oil passage 8.5. When the lifting directional valve 8.11 or the tilt directional valve 8.6 malfunctions, the main safety valve 8.14 opens, and the oil returns to the oil tank.

[0035] In a further embodiment, a speed limiter valve 4 and a shut-off valve 6 are connected between the lifting cylinder 5 and the multi-way valve 8; the speed limiter valve 4 and the shut-off valve 6 are existing devices in the hydraulic circuit of forklifts, and this application does not modify them. An oil suction filter 11 is connected to the oil inlet of the oil pump 1, and a return oil filter 9 is connected to the oil return port of the multi-way valve 8. The oil suction filter 11 and the return oil filter 9 are provided to filter the hydraulic oil and prevent clogging of the pipeline.

[0036] The specific work process is as follows:

[0037] 1. When the driver is correctly seated, the pressure switch closes, the relay closes, the descent solenoid valve 8.8 is energized and in the normally open position, its oil port a1 and oil port b1 are connected, the first descent control oil passage 8.10 of the multi-way valve 8 is connected to the second descent control oil passage 8.16, and the hydraulic control check valve 8.9 is in the normally open state under the action of oil pressure; while the oil inlet solenoid valve 8.3 is energized and in the normally open position, its oil port a2 and oil port b2 are disconnected, the first unloading oil passage 8.4 of the multi-way valve 8 is disconnected to the second unloading oil passage 8.17, and the hydraulic control slide valve 8.2 is in the left open state under the control of oil.

[0038] When oil pump 1 starts, the oil in oil tank 10 passes through oil suction filter 11 to oil pump outlet P, and then enters oil inlet P1 of multi-way valve 8. The oil is divided into two paths by diverter valve 8.15 in multi-way valve 8: one path supplies lifting cylinder 5 and tilting cylinder 7, and the other path supplies steering cylinder 3.

[0039] When the lifting control lever is in the low position, the lifting directional valve 8.11 is in the right position, the oil inlet solenoid valve 8.3 is energized and is in the normally open position, the first unloading oil passage 8.4 and the second unloading oil passage 8.17 are disconnected, the oil cannot be unloaded, and the hydraulic control check valve 8.9 can be opened. The oil entering the lifting directional valve 8.11 flows through the hydraulic control check valve 8.9 to the lifting oil port A1 of the multi-way valve 8, then through the oil port T2 and oil port P3 of the speed limit valve 4 to the oil port P4 of the shut-off valve 16, and finally into the lifting cylinder 6 to complete the lifting operation.

[0040] When the lifting control lever is in the high position, the lifting directional valve 8.11 is in the left position, and the lifting cylinder 5 descends under gravity. The hydraulic fluid enters the lifting port A1 of the multi-way valve 8 through the oil port P4 of the shut-off valve 6 and the oil port T2 of the speed limit valve 4. In addition, the descent solenoid valve 8.8 is energized and in the normally open position, connecting the first descent control oil passage 8.10 and the second descent control oil passage 8.16. The hydraulic oil enters the annular oil passage 8.1 through the lifting directional valve 8.11 and finally flows back to the oil tank 10 from the return oil port T1 of the multi-way valve 8 and the return oil filter 9, completing the descent.

[0041] When the tilt control lever is in the high position and the tilt directional valve 8.6 is in the left position, the oil enters the first unloading oil passage 8.4, the oil inlet solenoid valve 8.3 is energized and in the normally open position, the first unloading oil passage 8.4 is disconnected from the second unloading oil passage 8.17, the oil cannot be unloaded, and can only open the first check valve 8.7 to enter the tilt directional valve 8.6, and then enter the rodless chamber of the tilt cylinder 7 from the forward tilting port A2 of the multi-way valve 8, so that the tilt cylinder tilts forward. The oil in the rod chamber of the tilt cylinder 7 enters the return oil passage 8.5 through the backward tilting port B2 and the return oil port of the tilt directional valve 8.6, and then flows back to the oil tank 11 through the ring oil passage 8.1, the return oil port T1 of the multi-way valve 8, and the return oil filter 9, thus completing the forward tilting action.

[0042] When the tilt control lever is in the low position and the tilt directional valve 8.6 is in the right position, the oil enters the first unloading oil passage 8.4. The oil inlet solenoid valve 8.3 is energized and in the normally open position. The first unloading oil passage 8.4 is disconnected from the second unloading oil passage 8.17, and the oil cannot be unloaded. It can only open the first check valve 8.7 and enter the tilt directional valve 8.6. Then, it enters the rod chamber of the tilt cylinder 7 from the backward tilting port B2 of the multi-way valve 8, causing the tilt cylinder to tilt backward. The oil in the rodless chamber of the tilt cylinder 7 enters the ring oil passage 8.1 through the backward tilting port A2 and the return port of the tilt directional valve 8.6. It then flows back to the oil tank 10 from the return port T1 of the multi-way valve 8 and the return oil filter 9, completing the tilting action.

[0043] 2. When the driver is not seated correctly or not in the seat, the pressure switch is disconnected, the relay is disconnected, the descent solenoid valve 8.8 is de-energized and in the normally open position, oil port a1 and oil port b1 are disconnected, the first descent control oil passage 8.10 and the first descent control oil passage 8.16 of the multi-way valve 8 are disconnected, and the hydraulic control check valve 8.9 is in the open state under the control of the oil; the oil inlet solenoid valve 8.3 is de-energized and in the normally open position, oil port a2 and oil port b2 are connected, the first unloading oil passage 8.4 and the second unloading oil passage 8.17 of the multi-way valve 8 are connected, and the hydraulic control slide valve 8.2 is in the right-hand normally open state under the control of the oil.

[0044] When oil pump 1 starts, the oil in oil tank 10 passes through oil suction filter 11 to oil pump outlet P, then enters oil inlet P1 of multi-way valve 8, and then the oil is divided into two paths by flow divider valve 8.15 in multi-way valve 8: one path supplies lifting cylinder 5 and tilting cylinder 7, and the other path supplies steering cylinder 3.

[0045] When the lifting control lever is in the low position, and the lifting directional valve 8.11 is in the right position, the inlet solenoid valve 8.3 is de-energized and in the normally open position. The first unloading oil passage 8.4 and the second unloading oil passage 8.17 are connected. Under the control of the oil, the hydraulic control spool valve 8.2 is in the right-hand normally open state, while the lowering solenoid valve 8.8 and the hydraulic control check valve 8.9 are in the open state. Therefore, the oil entering the lifting directional valve 8.11 enters the annular oil passage 8.1 through its return port via the return oil passage 8.5, and finally flows back to the oil tank 10 through the return port T1 of the multi-way valve 8 and the return oil filter 9. That is, the oil is unloaded and cannot enter the lifting cylinder 5 from the lifting port A1 of the multi-way valve, so the gantry cannot be lifted.

[0046] When the hoisting control lever is in the high position, the hoisting reversing valve 8.11 is in the left position, and the hoisting cylinder 5 descends under the action of gravity. The oil flows through the shut-off valve 6 and the speed limiting valve 4 into the hoisting port A1 of the multi-way valve 8. The descent solenoid valve 8.8 is de-energized and is in the normally open position. The first descent control oil passage 8.10 and the second descent control oil passage 8.16 are disconnected. The hydraulic check valve 8.9 is closed and disconnected under the control of the oil. The oil cannot flow back to the oil tank 10 through the ring oil passage 8.1, and the gantry cannot descend.

[0047] Furthermore, regardless of whether the tilt control lever is in the high or low position, and whether the tilt directional valve 8.6 is in the right or left position, the inlet solenoid valve 8.3 is de-energized and in the normally open position. The first unloading oil passage 8.4 and the second unloading oil passage 8.17 are connected. Under the control of the oil, the hydraulic control spool valve 8.2 is in the right normally open state, while the first check valve 8.7 is open. The oil from the diverter valve 8.15 returns directly to the oil passage 8.5 and then enters the ring oil passage 8.1. Finally, it flows back to the oil tank 10 through the return port T1 of the multi-way valve 8 and the return oil filter 9. Since the oil cannot enter the forward tilt port A2 or the backward tilt port B2 of the multi-way valve during unloading, the gantry cannot tilt forward or backward.

[0048] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0049] Therefore, the above description is only a preferred embodiment of this application and is not intended to limit the scope of this application; that is, all equivalent modifications made in accordance with the scope of the claims of this application shall be within the protection scope of the claims of this application.

Claims

1. A safe forklift valve control system, comprising a multi-way valve (8), characterized in that: The multi-way valve (8) includes a lifting directional valve (8.11) and a tilting directional valve (8.6). A descent solenoid valve (8.8) is connected in series on the descent control oil passage of the multi-way valve (8). One end of the descent solenoid valve (8.8) is connected to the working port of the lifting directional valve (8.11) through the first descent control oil passage (8.10), and the other end is connected to the lifting cylinder (5) through the second descent control oil passage (8.16) and the annular oil passage (8.1). An oil inlet solenoid valve is connected in series on the return oil passage (8.5) of the multi-way valve (8). The solenoid valve (8.3) has one end connected to the pressure oil circuit of the multi-way valve (8) through the first unloading oil passage (8.4), and the other end connected to the return oil passage (8.5) of the multi-way valve through the second unloading oil passage (8.17); the power supply terminals of the lowering solenoid valve (8.8) and the inlet solenoid valve (8.3) are electrically connected to the pressure switch installed on the seat through a relay, and the opening and closing of the oil circuit of the lowering solenoid valve (8.8) and the inlet solenoid valve (8.3) is controlled by the switching of the pressure switch; The lifting control lever is installed on the lifting reversing valve (8.11), and the tilting control lever is installed on the tilting reversing valve (8.6). When the driver is correctly seated, the pressure switch is closed, and the lowering solenoid valve and the oil inlet solenoid valve are energized. The driver operates the lifting control lever and the tilting control lever in the multi-way valve to the high position and the low position, respectively, and the mast will lift, lower, tilt forward and backward, thereby driving the attachment to move. If the driver does not operate the lifting control lever and the tilting control lever and is in the neutral position, the mast will be stationary and the attachment will not move. When the driver is not seated or in an incorrect posture, the pressure switch will disconnect, and both the descent solenoid valve and the oil inlet solenoid valve will lose power. When the hoisting control lever and tilt control lever are in the high, medium, and low positions respectively, the mast will remain stationary and the attachments will not move.

2. The forklift valve control system according to claim 1, characterized in that: The multi-way valve (8) includes a diverter valve (8.15) connected to the oil outlet of the oil pump (1). One outlet of the diverter valve (8.15) is connected to the steering cylinder (3) via the steering gear (2). The other outlet of the diverter valve (8.15) is connected to the lifting directional valve (8.11), the tilting directional valve (8.6), and the hydraulic control slide valve (8.2), respectively. The two working ports of the lifting directional valve (8.11) are respectively connected to the hydraulic control check valve (8.9) and the lowering solenoid valve (8.8); The working port of the tilting reversing valve (8.6) is connected to the tilting cylinder (7); the hydraulic control slide valve (8.2) is connected to the oil inlet solenoid valve (8.3), and the return ports of the hydraulic control slide valve (8.2) and the oil inlet solenoid valve (8.3) are both connected to the oil tank (10).

3. The forklift valve control system according to claim 2, characterized in that: The hydraulic control check valve (8.9) is connected in series between the lifting directional valve (8.11) and the lifting cylinder (5) of the multi-way valve.

4. The forklift valve control system according to claim 2, characterized in that: One end of the inlet solenoid valve (8.3) is connected to the ring oil passage (8.1) through the second unloading oil passage (8.17), and the other end is connected to the control valve (8.2). The return port of the control valve (8.2) is connected to the oil tank (10) through the ring oil passage (8.1).

5. The forklift valve control system according to claim 2, characterized in that: A first check valve (8.7) is connected in series between the flow divider valve (8.15) and the tilt reversing valve (8.6).

6. The forklift valve control system according to claim 2, characterized in that: A speed limiting valve (4) and a shut-off valve (6) are connected between the lifting cylinder (5) and the multi-way valve (8); an oil suction filter (11) is connected to the oil inlet of the oil pump (1), and an oil return filter (9) is connected to the oil return port of the multi-way valve (8).

7. The forklift valve control system according to claim 2, characterized in that: The return ports of the lifting directional valve (8.11) and the tilting directional valve (8.6) are connected to the oil tank (10) in sequence through the return oil passage (8.5) and the ring oil passage (8.1).

8. The forklift valve control system according to claim 1, characterized in that: The lowering solenoid valve (8.8) is normally open, and the oil inlet solenoid valve (8.3) is normally closed. When the pressure switch is connected to the circuit, the lowering solenoid valve (8.8) is energized and opens the oil circuit, while the oil inlet solenoid valve (8.3) is energized and closes the oil circuit.

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