Hydraulic control system with self-locking function for lateral-moving single-fork distance-adjusting forklift and forklift

Abstract

The utility model discloses a lateral-moving single-fork distance-adjusting forklift hydraulic control system with a self-locking function and a forklift. The hydraulic control system comprises an oil pump, a multi-way valve, a right pallet fork distance-adjusting oil cylinder, a left pallet fork distance-adjusting oil cylinder, a bidirectional hydraulic lock and an oil tank. A first working oil port A1 of the multi-way valve is communicated with a rodless cavity of the right pallet fork distance adjusting oil cylinder, a second working oil port B1 of the multi-way valve is communicated with a first connector of the second three-way pipe, a second connector of the second three-way pipe is communicated with a rodless cavity of the left pallet fork distance adjusting oil cylinder, and a third connector of the second three-way pipe is communicated with a fourth working oil port C2 of the two-way hydraulic lock. A third working oil port C1 of the bidirectional hydraulic lock is communicated with a first connector of the first three-way pipe, and a second connector of the first three-way pipe is communicated with a rod cavity of the right pallet fork distance adjusting oil cylinder. According to the utility model, the bidirectional hydraulic lock is arranged on the accessory oil way, so that the problem that the other oil cylinder continues to act after the stroke of one oil cylinder is in place during lateral movement is solved, and the safety of lateral movement operation is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of forklifts, in particular to a hydraulic control system for a side-shifting single-fork adjustable-distance forklift with a self-locking function and a forklift. Background Art

[0002] Forklifts mainly use forks to pick up materials and carry them. Forklifts are usually equipped with different attachments to expand the scope of use of forklifts to meet the requirements of different working environments. The side-shifting adjustable distance fork is a commonly used attachment for forklifts. It supplies oil to the adjustment cylinder through a multi-way valve to push the fork to achieve the side shift and distance adjustment functions of the fork. Figure 2 As shown, the first attachment reversing valve plate 4 is operated to realize the left and right side movement of the fork, and the second attachment reversing valve plate 10 is operated to realize the distance adjustment of the left fork distance adjustment cylinder. Because it is a single fork distance adjustment, the actual operating stroke of the left and right fork distance adjustment cylinders cannot be guaranteed to be exactly the same (the theoretical design stroke is the same). The shortcomings of the existing side-shift single fork distance adjustment attachment hydraulic system are mainly the following:

[0003] (1) The first attachment reversing valve plate 4 performs reversing operation. When the fork moves to the right, oil enters the rodless chamber of the right fork distance adjusting cylinder 5, pushing the piston rod of the right fork distance adjusting cylinder 5 to drive the fork to move to the right. The pressure oil output from the rod chamber of the right fork distance adjusting cylinder 5 reaches the rod chamber of the left fork distance adjusting cylinder 6 through the first three-way pipe 7, pushing the piston rod of the left fork distance adjusting cylinder 6 to drive the fork to move to the right. The return oil from the rodless chamber of the left fork distance adjusting cylinder flows back to the oil tank through the first attachment reversing valve plate 4. If the running stroke of the right fork distance adjustment cylinder 5 is greater than that of the left fork distance adjustment cylinder 6, the left fork distance adjustment cylinder 6 reaches the stroke position first, and the right fork distance adjustment cylinder 5 has not reached the stroke position yet, and the first attachment reversing valve plate 4 is still in the reversing operation state, the pressure of the rodless chamber of the right fork distance adjustment cylinder 5 increases, and the pressure of the rod chamber of the right fork distance adjustment cylinder 5 also increases. Because of the area ratio of the rodless chamber to the rod chamber of the right fork distance adjustment cylinder 5, the pressure of the rod chamber is greater than the pressure of the rodless chamber. When the pressure increases to the pressure set by the first overload oil replenishment valve 13 connected to the rod chamber pipeline of the two cylinders, the first overload oil replenishment valve 13 is fully opened to overflow and return oil, and the right fork distance adjustment cylinder 5 will continue to move to the right. This poses a great danger to the side movement of the fork with load, and there is a safety hazard.

[0004] (2) The same problem occurs when the first attachment reversing valve plate 4 is reversing and the fork moves to the left.

[0005] (3) Although this problem can be solved by adjusting and increasing the pressure of the first overload oil replenishment valve 13, it will bring new problems. When the single fork distance adjustment action is performed, when the single fork distance adjustment stroke is in place, since the oil channel of the first overload oil replenishment valve 13 is connected to the rod chamber of the left and right fork distance adjustment cylinders, excessive pressure will also cause the other cylinder to drive the fork to move, which also poses a safety hazard. Utility Model Content

[0006] Based on the technical problems existing in the background technology, the utility model proposes a side-shifting single-fork adjustable distance forklift hydraulic control system and a forklift with a self-locking function. By arranging a two-way hydraulic lock on the accessory oil circuit, the problem that when one cylinder has reached its stroke during side-shifting operation, the other cylinder continues to move, thereby improving the safety of side-shifting operation.

[0007] The utility model provides a hydraulic control system for a side-shifting single-fork distance-adjusting forklift with a self-locking function, comprising an oil pump, a multi-way valve, a right fork distance-adjusting oil cylinder, a left fork distance-adjusting oil cylinder, a two-way hydraulic lock and an oil tank;

[0008] The oil suction port of the oil pump is communicated with the oil tank, and the oil outlet of the oil pump is communicated with the oil inlet P of the multi-way valve;

[0009] The bidirectional hydraulic lock includes four working oil ports, namely, a first working oil port V1, a second working oil port V2, a third working oil port C1 and a fourth working oil port C2;

[0010] The first working oil port A1 of the multi-way valve is communicated with the rodless chamber of the right fork distance adjustment cylinder, the second working oil port B1 of the multi-way valve is communicated with the first interface of the second three-way pipe, the second interface of the second three-way pipe is communicated with the rodless chamber of the left fork distance adjustment cylinder, the third interface of the second three-way pipe is communicated with the fourth working oil port C2 of the two-way hydraulic lock, the third working oil port A2 of the multi-way valve is communicated with the first working oil port V1 of the two-way hydraulic lock, and the fourth working oil port B2 of the multi-way valve is communicated with the second working oil port V2 of the two-way hydraulic lock;

[0011] The third working oil port C1 of the bidirectional hydraulic lock is communicated with the first interface of the first three-way pipe, the second interface of the first three-way pipe is communicated with the rod chamber of the right fork distance adjusting cylinder, and the third interface of the first three-way pipe is communicated with the rod chamber of the left fork distance adjusting cylinder.

[0012] Preferably, the multi-way valve includes a first accessory reversing valve plate and a second accessory reversing valve plate, the first accessory reversing valve plate is connected to a first working oil port A1 and a second working oil port B1, the second accessory reversing valve plate is connected to a third working oil port A2 and a fourth working oil port B2, and the oil inlet P of the multi-way valve is divided into two paths through an internal oil circuit, one path is connected to the inlet of the safety valve, the outlet of the safety valve is connected to the oil tank, and the other path is connected to the oil inlet of the first accessory reversing valve plate and the second accessory reversing valve plate.

[0013] Preferably, the third working oil port A2 of the second attachment reversing valve plate is connected to the oil inlet of the first overload oil replenishing valve through a third three-way pipe, and the oil outlet of the first overload oil replenishing valve is connected to the annular oil return channel, and the fourth working oil port B2 of the second attachment reversing valve plate is connected to the oil inlet of the second overload oil replenishing valve through a fourth three-way pipe, and the oil outlet of the second overload oil replenishing valve is connected to the annular oil return channel; the annular oil return channel is connected to the oil return port T of the multi-way valve, and the oil return port T is connected to the oil tank.

[0014] Preferably, when the first accessory reversing valve plate and the second accessory reversing valve plate are in the middle position, the oil inlet P of the multi-way valve is connected with the oil return port T of the multi-way valve through the middle oil passage of the first accessory reversing valve plate and the second accessory reversing valve plate, and the oil return port T is connected with the oil tank.

[0015] Preferably, the first attachment reversing valve plate and the second attachment reversing valve plate are connected in parallel.

[0016] Preferably, when the first working oil port V1 of the two-way hydraulic lock is connected to the pressurized oil, the first working oil port V1 is connected to the third working oil port C1, and the fourth working oil port C2 is connected to the second working oil port V2 in the opposite direction through the internal control oil circuit connected between the two-way hydraulic lock and the first working oil port V1; when the second working oil port V2 of the two-way hydraulic lock is connected to the pressurized oil, the second working oil port V2 is connected to the fourth working oil port C2, and the third working oil port C1 is connected to the first working oil port V1 in the opposite direction through the internal control oil circuit connected between the two-way hydraulic lock and the second working oil port V2; conversely, when the third working oil port C1 or the fourth working oil port C2 of the two-way hydraulic lock is connected to the pressurized oil, the two-way hydraulic lock is reversely cut off, the third working oil port C1 is not connected to the first working oil port V1, and the fourth working oil port C2 is also not connected to the second working oil port V2.

[0017] The forklift provided by the utility model comprises the above-mentioned hydraulic control system of the side-shifting single-fork adjustable-distance forklift with self-locking function.

[0018] Beneficial technical effects of the utility model:

[0019] 1. The utility model solves the problem that when one oil cylinder reaches the designated position during lateral movement, the other oil cylinder continues to move by arranging a two-way hydraulic lock on the oil circuit of the attachment, thereby improving the safety of lateral movement.

[0020] 2. The utility model utilizes two oil cylinders and realizes not only the side shift function but also the single fork distance adjustment function through the conversion design of the oil circuit of the accessories. The system has a simple structure, comprehensive functions and convenient operation.

[0021] 3. The utility model prevents damage to the oil cylinder due to excessive pressure by arranging an overload valve and an oil replenishing valve in the oil circuit of the attachment, thereby increasing the service life of the attachment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the hydraulic control system of the side-shifting single-fork adjustable-distance forklift with self-locking function proposed by the utility model;

[0023] Figure 2 This is the schematic diagram of the hydraulic system of the existing side-shift single-fork distance-adjusting attachment.

[0024] In the figure: 1-oil pump, 2-safety valve, 3-multi-way valve, 4-first attachment reversing valve plate, 5-right fork distance adjusting cylinder, 6-left fork distance adjusting cylinder, 7-first three-way pipe, 8-second three-way pipe, 9-two-way hydraulic lock, 10-second attachment reversing valve plate, 11-third three-way pipe, 12-fourth three-way pipe, 13-first overload oil replenishing valve, 14-second overload oil replenishing valve, 15-annular oil return channel, 16-oil tank. DETAILED DESCRIPTION

[0025] The present invention will be further explained below in conjunction with specific embodiments. Example

[0026] Reference Figure 1 The utility model proposes a hydraulic control system for a side-shifting single-fork adjustable-distance forklift with a self-locking function.

[0027] The hydraulic control system of the side-shifting single-fork distance-adjusting forklift with self-locking function proposed in the utility model comprises an oil pump 1, a multi-way valve 3, a right fork distance-adjusting oil cylinder 5, a left fork distance-adjusting oil cylinder 6, a two-way hydraulic lock 9 and an oil tank 16;

[0028] The oil suction port of the oil pump 1 is connected to the oil tank 16, and the oil outlet of the oil pump 1 is connected to the oil inlet P of the multi-way valve 3;

[0029] The bidirectional hydraulic lock 9 includes four working oil ports, namely, a first working oil port V1, a second working oil port V2, a third working oil port C1 and a fourth working oil port C2;

[0030] The first working oil port A1 of the multi-way valve 3 is communicated with the rodless chamber of the right fork distance adjusting cylinder 5, the second working oil port B1 of the multi-way valve 3 is communicated with the first interface of the second three-way pipe 8, the second interface of the second three-way pipe 8 is communicated with the rodless chamber of the left fork distance adjusting cylinder 6, the third interface of the second three-way pipe 8 is communicated with the fourth working oil port C2 of the two-way hydraulic lock 9, the third working oil port A2 of the multi-way valve is communicated with the first working oil port V1 of the two-way hydraulic lock 9, and the fourth working oil port B2 of the multi-way valve is communicated with the second working oil port V2 of the two-way hydraulic lock 9;

[0031] The third working oil port C1 of the bidirectional hydraulic lock 9 is connected to the first interface of the first three-way pipe 7, the second interface of the first three-way pipe 7 is connected to the rod chamber of the right fork distance adjusting cylinder 5, and the third interface of the first three-way pipe 7 is connected to the rod chamber of the left fork distance adjusting cylinder 6.

[0032] The multi-way valve 3 comprises a first accessory reversing valve disc 4 and a second accessory reversing valve disc 10. The first accessory reversing valve disc 4 is connected to a first working oil port A1 and a second working oil port B1. The second accessory reversing valve disc 10 is connected to a third working oil port A2 and a fourth working oil port B2. The oil inlet P of the multi-way valve 3 is divided into two paths through an internal oil circuit. One path is connected to the inlet of the safety valve 2. The outlet of the safety valve 2 is connected to the oil tank 16 through the annular oil return passage (15) of the multi-way valve (3) and the oil return port T of the multi-way valve (3). The other path is connected to the oil inlet of the first accessory reversing valve disc 4 and the second accessory reversing valve disc 10.

[0033] The third working oil port A2 of the second attachment reversing valve plate 10 is connected to the oil inlet of the first overload oil replenishing valve 13 through the third three-way pipe 11, and the oil outlet of the first overload oil replenishing valve 13 is connected to the annular oil return channel 15. The fourth working oil port B2 of the second attachment reversing valve plate 10 is connected to the oil inlet of the second overload oil replenishing valve 14 through the fourth three-way pipe 12, and the oil outlet of the second overload oil replenishing valve 14 is connected to the annular oil return channel 15; the annular oil return channel 15 is connected to the oil return port T of the multi-way valve 3, and the oil return port T is connected to the oil tank 16.

[0034] When the first accessory reversing valve plate 4 and the second accessory reversing valve plate 10 are in the middle position, the oil inlet P of the multi-way valve 3 is connected with the oil return port T of the multi-way valve 3 through the middle position oil passage of the first accessory reversing valve plate 4 and the second accessory reversing valve plate 10, and the oil return port T is connected with the oil tank 16.

[0035] The first attachment reversing valve disc 4 and the second attachment reversing valve disc 10 are connected in parallel.

[0036] When the first working oil port V1 of the two-way hydraulic lock 9 is connected with pressurized oil, the first working oil port V1 is connected with the third working oil port C1, and the fourth working oil port C2 is connected with the second working oil port V2 in the opposite direction through the internal control oil circuit of the two-way hydraulic lock 9 connected with the first working oil port V1; when the second working oil port V2 of the two-way hydraulic lock 9 is connected with pressurized oil, the second working oil port V2 is connected with the fourth working oil port C2, and the third working oil port C1 is connected with the first working oil port V1 in the opposite direction through the internal control oil circuit of the two-way hydraulic lock 9 connected with the second working oil port V2; conversely, when the third working oil port C1 or the fourth working oil port C2 of the two-way hydraulic lock 9 is connected with pressurized oil, the two-way hydraulic lock 9 is reversely cut off, the third working oil port C1 is not connected with the first working oil port V1, and the fourth working oil port C2 is also not connected with the second working oil port V2.

[0037] Working principle:

[0038] During operation, when the fork does not need to move, the first attachment reversing valve plate 4 and the second attachment reversing valve plate 10 are both in the middle position; the hydraulic oil output by the oil pump 1 flows back to the hydraulic oil tank 16 through the middle oil channel of the multi-way valve 3.

[0039] When the forklift fork performs a sideways movement, the first attachment reversing valve plate 4 is in the reversing position. When the pressure oil output by the oil pump 1 is connected to the first working oil port A1 of the first attachment reversing valve plate 4 through the oil inlet P of the multi-way valve 3, the pressure oil output by the oil pump 1 reaches the rodless chamber of the right fork distance adjusting cylinder 5 through the first working oil port A1 of the first attachment reversing valve plate 4, and pushes the piston rod of the right fork distance adjusting cylinder 5 to drive the fork to move to the right. The pressure oil output by the rod chamber of the right fork distance adjusting cylinder 5 reaches the rod chamber of the left fork distance adjusting cylinder 6 through the three-way pipe 7, and pushes the piston rod of the left fork distance adjusting cylinder 6 to drive the fork to move to the right. The pressure oil output by the rodless chamber of the left fork distance adjusting cylinder 6 flows back to the oil tank through the three-way pipe 8 and the second working oil port B1 of the first attachment reversing valve plate 4, realizing the right side movement of the fork. Similarly, when the pressure oil output by the oil pump 1 is connected to the second working oil port B1 of the first attachment reversing valve plate 4, the pressure oil output by the oil pump 1 reaches the rodless chamber of the left fork distance adjusting cylinder 6 through the second working oil port B1 of the first attachment reversing valve plate 4 and the second interface of the three-way pipe 8, pushing the piston rod of the left fork distance adjusting cylinder 6 to drive the fork to move to the left, and the pressure oil output by the rod chamber of the left fork distance adjusting cylinder 6 reaches the rod chamber of the right fork distance adjusting cylinder 5 through the three-way pipe 7, pushing the piston rod of the right fork distance adjusting cylinder 5 to drive the fork to move to the left, and the pressure oil output by the rodless chamber of the left fork distance adjusting cylinder 5 flows back to the oil tank through the first working oil port A1 of the first attachment reversing valve plate 4, realizing the left side movement of the fork.

[0040] When the forklift fork needs to adjust the fork distance, the second attachment reversing valve plate 10 is in the reversing position. When the pressure oil output by the oil pump 1 is connected to the third working oil port A2 of the second attachment reversing valve plate 10, the pressure oil output by the oil pump 1 passes through the third working oil port A2 of the second attachment reversing valve plate 10, the first working oil port V1 of the two-way hydraulic lock 9, and the third working oil port C1 of the two-way hydraulic lock 9 to reach the rod chamber of the left fork distance adjusting cylinder 6, pushing the piston rod of the left fork distance adjusting cylinder 6 to drive the fork to move to the right. The rodless chamber of the left fork distance adjusting cylinder 6 The output pressure oil reaches the fourth working oil port C2 of the two-way hydraulic lock 9 through the third interface of the three-way pipe 8. Since the first working oil port V1 of the two-way hydraulic lock 9 passes through the pressure oil, the internal control oil circuit connected with the first working oil port V1 through the two-way hydraulic lock 9, and the fourth working oil port C2 and the second working oil port V2 are reversely conducted. Therefore, the pressure oil output from the rodless chamber of the left fork distance adjustment cylinder 6 passes through the fourth working oil port C2 of the two-way hydraulic lock 9, and flows back to the oil tank via the second working oil port V2 and the fourth working oil port B2 of the second accessory reversing valve plate 10. Similarly, when the pressure oil output by the oil pump 1 is connected to the fourth working oil port B2 of the second attachment reversing valve plate 10, the pressure oil output by the oil pump 1 reaches the rodless chamber of the left fork distance adjustment cylinder 6 through the fourth working oil port B2 of the second attachment reversing valve plate 10, the second working oil port V2 of the two-way hydraulic lock 9, the fourth working oil port C2 of the two-way hydraulic lock 9, and the second interface of the three-way pipe 8, pushing the piston rod of the left fork distance adjustment cylinder 6 to drive the fork to move to the left, and the pressure oil output from the rod chamber of the left fork distance adjustment cylinder 6 reaches the two-way hydraulic lock 9 through the first interface of the three-way pipe 7. The third working oil port C1, because the second working oil port V2 of the two-way hydraulic lock 9 passes through the pressure oil, through the internal control oil circuit connected with the second working oil port V2 of the two-way hydraulic lock 9, the third working oil port C1 and the first working oil port V1 are reversely conducted, so the pressure oil output from the rod chamber of the left fork distance adjustment cylinder 6 flows back to the oil tank through the third working oil port C1 of the two-way hydraulic lock 9, the first working oil port V1, and the third working oil port A2 of the second attachment reversing valve plate 10, so as to realize the single fork distance adjustment.

[0041] During the rightward movement, when the operating stroke of the right fork distance adjusting cylinder 5 is greater than the stroke of the left fork distance adjusting cylinder 6, the stroke of the left fork distance adjusting cylinder 6 is in place first, and the stroke of the right fork distance adjusting cylinder 5 is not in place yet. The first attachment reversing valve plate 4 is still in the reversing operation state, and the pressure in the rodless chamber of the right fork distance adjusting cylinder 5 increases, and the pressure in the rod chamber of the right fork distance adjusting cylinder 5 also increases. Because the rod chamber of the right fork distance adjusting cylinder 5 is connected to the third working oil port C1 of the two-way hydraulic lock 9, the two-way hydraulic lock 9 is reversely cut off, C1 and V1 are not connected, so the right fork distance adjusting cylinder 5 remains stationary. Similarly, during the leftward movement, when the running stroke of the left fork distance adjustment cylinder 6 is greater than the stroke of the right fork distance adjustment cylinder 5, the right fork distance adjustment cylinder 5 is in place first, and the left fork distance adjustment cylinder 6 is not in place yet. The first attachment reversing valve plate 4 is still in the reversing operation state, and the pressure of the rodless chamber of the left fork distance adjustment cylinder 6 increases, and the pressure of the rod chamber of the left fork distance adjustment cylinder 6 also increases. Because the rod chamber of the left fork distance adjustment cylinder 6 is connected to the third working oil port C1 of the two-way hydraulic lock 9, the two-way hydraulic lock 9 is reversely cut off, and C1 and V1 are not connected, so the left fork distance adjustment cylinder 5 remains motionless. At the same time, during the leftward movement, the fourth working oil port C2 of the two-way hydraulic lock 9 connected to the rodless chamber of the left fork distance adjustment cylinder 6 passes the pressure oil, the two-way hydraulic lock 9 is reversely cut off, and C2 and V2 are not connected. The safety of the lateral movement is guaranteed. Example

[0042] The forklift provided by the utility model comprises the hydraulic control system of the side-shifting single-fork adjustable-distance forklift with self-locking function described in the first embodiment.

Claims

1. Hydraulic control system for side-shift single-fork adjustable-distance forklift with self-locking function, characterized in that: It comprises an oil pump (1), a multi-way valve (3), a right fork distance adjusting oil cylinder (5), a left fork distance adjusting oil cylinder (6), a two-way hydraulic lock (9) and an oil tank (16); The oil suction port of the oil pump (1) is in communication with the oil tank (16), and the oil outlet of the oil pump (1) is in communication with the oil inlet P of the multi-way valve (3); The bidirectional hydraulic lock (9) comprises four working oil ports, namely a first working oil port V1, a second working oil port V2, a third working oil port C1 and a fourth working oil port C2; The first working oil port A1 of the multi-way valve (3) is communicated with the rodless chamber of the right fork distance adjusting cylinder (5), the second working oil port B1 of the multi-way valve (3) is communicated with the first interface of the second three-way pipe (8), the second interface of the second three-way pipe (8) is communicated with the rodless chamber of the left fork distance adjusting cylinder (6), the third interface of the second three-way pipe (8) is communicated with the fourth working oil port C2 of the two-way hydraulic lock (9), the third working oil port A2 of the multi-way valve (3) is communicated with the first working oil port V1 of the two-way hydraulic lock (9), and the fourth working oil port B2 of the multi-way valve (3) is communicated with the second working oil port V2 of the two-way hydraulic lock (9); The third working oil port C1 of the bidirectional hydraulic lock (9) is communicated with the first interface of the first three-way pipe (7), the second interface of the first three-way pipe (7) is communicated with the rod chamber of the right fork distance adjusting cylinder (5), and the third interface of the first three-way pipe (7) is communicated with the rod chamber of the left fork distance adjusting cylinder (6).

2. The hydraulic control system of a side-shifting single-fork adjustable-distance forklift with self-locking function according to claim 1 is characterized in that: The multi-way valve (3) comprises a first accessory reversing valve disc (4) and a second accessory reversing valve disc (10); the first accessory reversing valve disc (4) is connected to a first working oil port A1 and a second working oil port B1; the second accessory reversing valve disc (10) is connected to a third working oil port A2 and a fourth working oil port B2; an oil inlet P of the multi-way valve (3) is divided into two paths through an internal oil circuit, one path is connected to the inlet of the safety valve (2); the outlet of the safety valve (2) is connected to the oil tank (16) through an annular oil return passage (15) of the multi-way valve (3) and an oil return port T of the multi-way valve (3); and the other path is connected to the oil inlets of the first accessory reversing valve disc (4) and the second accessory reversing valve disc (10).

3. The hydraulic control system of a side-shifting single-fork adjustable-distance forklift with self-locking function according to claim 2 is characterized in that: The third working oil port A2 of the second attachment reversing valve plate (10) is communicated with the oil inlet of the first overload oil replenishing valve (13) through the third three-way pipe (11), and the oil outlet of the first overload oil replenishing valve (13) is communicated with the annular oil return passage (15); the fourth working oil port B2 of the second attachment reversing valve plate (10) is communicated with the oil inlet of the second overload oil replenishing valve (14) through the fourth three-way pipe (12), and the oil outlet of the second overload oil replenishing valve (14) is communicated with the annular oil return passage (15); the annular oil return passage (15) is communicated with the oil return port T of the multi-way valve (3), and the oil return port T is communicated with the oil tank (16).

4. The hydraulic control system of a side-shifting single-fork adjustable-distance forklift with self-locking function according to claim 2 is characterized in that: When the first accessory reversing valve plate (4) and the second accessory reversing valve plate (10) are in a neutral position, the oil inlet port P of the multi-way valve (3) is connected to the oil return port T of the multi-way valve (3) through the neutral oil passage of the first accessory reversing valve plate (4) and the second accessory reversing valve plate (10), and the oil return port T is connected to the oil tank (16).

5. The hydraulic control system of a side-shifting single-fork adjustable-distance forklift with self-locking function according to claim 2, characterized in that: The first attachment reversing valve plate (4) and the second attachment reversing valve plate (10) are connected in parallel.

6. The hydraulic control system of a side-shifting single-fork adjustable-distance forklift with self-locking function according to claim 1, characterized in that: When the first working oil port V1 of the bidirectional hydraulic lock (9) is connected to the pressure oil, the first working oil port V1 is connected to the third working oil port C1, and the fourth working oil port C2 is connected to the second working oil port V2 in the opposite direction through the internal control oil circuit connected between the bidirectional hydraulic lock (9) and the first working oil port V1; when the second working oil port V2 of the bidirectional hydraulic lock (9) is connected to the pressure oil, the second working oil port V2 is connected to the fourth working oil port C2, and the third working oil port C1 is connected to the first working oil port V1 in the opposite direction through the internal control oil circuit connected between the bidirectional hydraulic lock (9) and the second working oil port V2; On the contrary, when the third working oil port C1 or the fourth working oil port C2 of the bidirectional hydraulic lock (9) is connected to the pressurized oil, the bidirectional hydraulic lock (9) is reversely blocked, the third working oil port C1 is disconnected from the first working oil port V1, and the fourth working oil port C2 is disconnected from the second working oil port V2.

7. A forklift, characterized in that: The invention comprises a hydraulic control system of a side-shifting single-fork adjustable-distance forklift with a self-locking function as described in any one of claims 1 to 6.

Images