Hydraulic logic control system for sidesway distance adjusting fork

Abstract

The invention discloses a hydraulic logic control system for a sidesway distance adjusting fork. Comprising an oil pump, a safety valve, a first reversing valve plate, a logic control valve block, a first hydraulic control one-way valve, a first three-way pipe, a right pallet fork distance adjusting oil cylinder, a left pallet fork distance adjusting oil cylinder, a first overload valve, a second hydraulic control one-way valve, a second three-way pipe, a third three-way pipe, a second hydraulic control one-way valve, a throttling valve, a second reversing valve plate and a second overload valve. The logic control valve block comprises a second hydraulic control one-way valve, a second hydraulic control one-way valve, a throttling valve and a second overload valve, and the second hydraulic control one-way valve, the second hydraulic control one-way valve, the throttling valve and the second overload valve are communicated through pipelines. And the first reversing valve plate is communicated with the second reversing valve plate. According to the hydraulic logic control system for the laterally-moving distance adjusting fork, the purpose of hydraulic oil way regulation and control is achieved through structural arrangement.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic systems, in particular to a hydraulic logic control system for a side-shift distance-adjusting fork. Background Art

[0002] Forklifts mainly use forks to pick up materials and carry them. Forklifts are usually equipped with different attachments to expand the use of forklifts to meet the requirements of different working environments. Side shift fork is a commonly used attachment for forklifts. It supplies oil to the adjustment cylinder through a pump and a multi-way valve to push the fork to achieve the side shift and distance adjustment function of the fork. The shortcomings of the existing hydraulic system of side shift fork attachments are mainly as follows:

[0003] 1. The side shift of the fork needs to be controlled by a separate cylinder, and two additional cylinders are set to control the distance adjustment. The structure is complex and bulky, which is not economical;

[0004] 2. The two forks are controlled by two oil cylinders to adjust the distance. A single fork can be adjusted left and right (the other fork does not move), which is time-consuming and labor-intensive, and has low work efficiency.

[0005] 3. There is also a method of adjusting the distance (expansion and contraction) between the two forks by adding a solenoid valve. Not only is the speed control characteristic poor, but also the pressure shock during operation can easily cause deformation and damage to the cylinder piston rod.

[0006] 4. During the left and right lateral movement of the fork, when one cylinder has reached its stroke and the other cylinder has not yet reached its stroke, the inevitable internal leakage of the control valve core will cause problems with the movement of the other cylinder. Summary of the invention

[0007] The object of the present invention is to provide a hydraulic logic control system for a side-shift distance-adjusting fork, so as to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above-mentioned object, the present invention provides the following technical solutions: a hydraulic logic control system for a side shifting distance adjusting fork, comprising an oil pump, a safety valve, a first reversing valve plate, a logic control valve block, a first hydraulically controlled one-way valve, a first three-way pipe, a right fork distance adjusting oil cylinder, a left fork distance adjusting oil cylinder, a first overload valve, a second hydraulically controlled one-way valve, a second three-way pipe, a third three-way pipe, a second hydraulically controlled one-way valve, a throttle valve, a second reversing valve plate, and a second overload valve;

[0009] The logic control valve block includes a second hydraulically controlled one-way valve, a second hydraulically controlled one-way valve, a throttle valve and a second overload valve, and the second hydraulically controlled one-way valve, the second hydraulically controlled one-way valve, the throttle valve and the second overload valve are connected through a pipeline;

[0010] The first reversing valve plate is connected to the second reversing valve plate, the oil pump is connected to the second overload valve, and the oil pump is also connected to the oil tank through a safety valve, the first reversing valve plate and the second reversing valve plate are connected to the oil tank, the first reversing valve plate is connected to the logic control valve block, the logic control valve block is connected to the first three-way pipe, the first three-way pipe is connected to the right fork distance adjusting cylinder, and the first three-way pipe is also connected to the left fork distance adjusting cylinder.

[0011] Specifically, the second three-way pipe is connected to the second reversing valve plate, and the second three-way pipe is also connected to the logic control valve block and the left fork distance adjusting cylinder. The second reversing valve plate is connected to the third three-way pipe, and the third three-way pipe is connected to the logic control valve block and the right fork distance adjusting cylinder.

[0012] Specifically, the first overload valve is communicated with the logic control valve block, and the second overload valve is communicated with the logic control valve block.

[0013] Specifically, the logic control valve block is controlled to communicate through a second hydraulically controlled one-way valve and a second hydraulically controlled one-way valve.

[0014] Specifically, the first overload valve and the second overload valve are used to limit the maximum pressure of the rod chambers of the left and right fork distance adjustment cylinders and to prevent impact caused by excessive pressure.

[0015] Specifically, the throttle valve is used for bypass unloading and adjusting the movement speed of the two chambers of the oil cylinder.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention utilizes two oil cylinders and three hydraulically controlled one-way valves, and through the logic conversion design of the oil circuit, it can not only realize the side shift function, but also realize the double-fork distance adjustment function. The system has a simple structure, comprehensive functions and is easy to operate.

[0018] 2. The present invention realizes the lateral shifting and distance adjustment action of the double forks driven by the double cylinders by arranging a hydraulically controlled one-way valve on the attachment oil circuit, avoids the problem that after one cylinder has reached its stroke, the other cylinder continues to move, and improves the safety of the lateral shifting operation.

[0019] 3. An overload valve is installed in the oil circuit of the logic valve block to prevent the impact damage of the cylinder due to excessive pressure and increase the service life of the accessories. At the same time, a throttle valve is installed in parallel in the oil circuit of the logic valve block, which can play a role of bypass unloading on the one hand and adjust the movement speed of the cylinder on the other hand. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the main structure of the present invention.

[0021] In the figure: 1-oil pump; 2-safety valve; 3-first reversing valve plate; 4-logic control valve block; 5-first hydraulically controlled one-way valve; 6-first three-way pipe; 7-right fork distance adjusting cylinder; 8-left fork distance adjusting cylinder; 9-first overload valve; 10-second hydraulically controlled one-way valve; 11-second three-way pipe; 12-third three-way pipe; 13-second hydraulically controlled one-way valve; 14-throttle valve; 15-second reversing valve plate; 16-second overload valve; 17-oil tank. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] See also Figure 1 The present invention provides a technical solution: a hydraulic logic control system for a side shift distance adjusting fork, the hydraulic oil circuit with logic control and side shift distance adjusting function includes an oil pump 1, a safety valve 2, a first reversing valve plate 3, a logic control valve block 4, a first hydraulically controlled one-way valve 5, a right fork distance adjusting cylinder 7, a left fork distance adjusting cylinder 8, a first overload valve 9, a second hydraulically controlled one-way valve 10, a third hydraulically controlled one-way valve 13, a throttle valve 14, a second reversing valve plate 15, a second overload valve 16, an oil tank 17 and other components; the logic control valve block 4 includes the first hydraulically controlled one-way valve 5, the first overload valve 9, the second hydraulically controlled one-way valve 10, the third hydraulically controlled one-way valve 13, the throttle valve 14, the second overload valve 16 and other components; the various components are connected by pipelines.

[0024] The first reversing valve plate 3 and the second reversing valve plate 15 are connected in parallel.

[0025] The logic control valve block 4 has five working oil ports, namely a first working oil port V1 and a second working oil port V2 connected to the reversing valve, and a third working oil port C1, a fourth working oil port C2 and a fifth working oil port C3 connected to the oil cylinder.

[0026] Characteristic description: The oil suction port of the oil pump 1 is connected to the hydraulic oil tank 16, and the oil outlet of the oil pump 1 is divided into two paths, one of which is connected to the inlet of the system safety valve 2, and the outlet of the safety valve 2 is connected to the oil tank 17; the other path is connected to the oil inlet P of the first reversing valve plate 3 and the second reversing valve plate 15 connected in parallel; the oil return port T of the first reversing valve plate 3 and the second reversing valve plate 15 connected in parallel is connected to the oil tank 17. The first working oil port A1 of the first reversing valve plate 3 is connected to the first working oil port V1 of the logic control valve block 4; the second working oil port B1 of the first reversing valve plate 3 is connected to the second working oil port V2 of the logic control valve block 4.

[0027] The inside of the logic control valve block 4 is connected with the first working oil port V1 as follows: the throttle valve oil port a, the working oil port D of the first hydraulically controlled one-way valve 5, the return oil port f of the second overload valve 16, the oil inlet c of the first overload valve 9, and the control oil passages of the second hydraulically controlled one-way valve 10 and the third hydraulically controlled one-way valve 13. The throttle valve oil port b, the working oil port E of the second hydraulically controlled one-way valve 10, the working oil port F of the third hydraulically controlled one-way valve 13, the oil inlet e of the second overload valve 16, the oil outlet d of the first overload valve 9, and the control oil passage of the first hydraulically controlled one-way valve 5 are connected with the second working oil port V2.

[0028] The third working oil port C1 of the logic control valve block 4 is communicated with the first interface of the first three-way pipe 6; the second interface of the first three-way pipe 6 is communicated with the rod chamber of the right fork distance adjusting cylinder 7; the third interface of the first three-way pipe 6 is communicated with the rod chamber of the left fork distance adjusting cylinder 8.

[0029] The first working oil port A2 of the second reversing valve plate 15 is communicated with the first interface of the second three-way pipe 11; the second interface of the second three-way pipe 11 is communicated with the fourth working oil port C2 of the logic control valve block 4; the third interface of the second three-way pipe 11 is communicated with the rodless chamber of the left fork distance adjustment cylinder 8. The second working oil port B2 of the second reversing valve plate 15 is communicated with the first interface of the third three-way pipe 12; the second interface of the third three-way pipe 12 is communicated with the fifth working oil port C3 of the logic control valve block 4; the third interface of the third three-way pipe 12 is communicated with the rodless chamber of the right fork distance adjustment cylinder 7.

[0030] When the first reversing valve plate 3 and the second reversing valve plate 15 are in the middle position, the oil inlet P is connected to the oil return port T, and the oil return port T is connected to the hydraulic oil tank 17 .

[0031] The oil inlet c of the first overload valve 9 is communicated with the first working oil port V1 of the logic control valve block 4 ; the oil outlet d of the first overload valve 9 is communicated with the second working oil port V2 of the logic control valve block 4 .

[0032] The oil inlet e of the second overload valve 16 is communicated with the second working oil port V2 of the logic control valve block 4 ; the oil outlet f of the second overload valve 16 is communicated with the first working oil port V1 of the logic control valve block 4 .

[0033] When the first working oil port V1 of the logic control valve block 4 is connected to the pressure oil, the working oil port D of the first hydraulically controlled one-way valve 5 is connected to the third working oil port C1 of the logic control valve block 4 in a forward direction; at the same time, the second hydraulically controlled one-way valve 10 and the third hydraulically controlled one-way valve 13 are reversely connected through the internal control oil circuit of the second hydraulically controlled one-way valve 10 and the third hydraulically controlled one-way valve 13 connected to the first working oil port V1 of the logic control valve block 4, that is, the fourth working oil port C2 is connected to the working oil port E of the second hydraulically controlled one-way valve 10, and the fifth working oil port C3 is connected to the working oil port F of the third hydraulically controlled one-way valve 13. When the second working oil port V2 of the logic control valve block 4 is connected to the pressure oil, the working oil port E of the second hydraulically controlled one-way valve 10 is connected to the fourth working oil port C2 of the logic control valve block 4 in a forward direction; the working oil port F of the third hydraulically controlled one-way valve 13 is connected to the fifth working oil port C3 of the logic control valve block 4 in a forward direction. At the same time, through the internal control oil circuit of the first hydraulically controlled one-way valve 5 connected to the second working oil port V2 of the logic control valve block 4, the first hydraulically controlled one-way valve 5 is reversely conducted, that is, the third working oil port C1 of the logic control valve block 4 is conducted with the working oil port D of the first hydraulically controlled one-way valve 5; on the contrary, when the third working oil port C1 of the logic control valve block 4 is passed with pressurized oil, and the control oil circuit of the first hydraulically controlled one-way valve 5 is not passed with pressurized oil, the first hydraulically controlled one-way valve 5 is reversely cut off, and the third working oil port C1 of the logic control valve block 4 is not connected with the working oil port D of the first hydraulically controlled one-way valve 5. When the fourth working oil port C2 or the fifth working oil port C3 of the logic control valve block 4 is connected to the pressurized oil, and the control oil circuits of the second hydraulically controlled one-way valve 10 and the third hydraulically controlled one-way valve 13 are blocked with pressurized oil, the second hydraulically controlled one-way valve 10 and the third hydraulically controlled one-way valve 13 are reversely cut off, the fourth working oil port C2 of the logic control valve block 4 is blocked from the working oil port E of the second hydraulically controlled one-way valve 10, and the fifth working oil port C3 of the logic control valve block 4 is blocked from the working oil port F of the third hydraulically controlled one-way valve 13.

[0034] The first overload valve 9 and the second overload valve 16 are used to limit the maximum pressure of the rod chambers of the left and right fork distance adjustment cylinders and to prevent impact caused by excessive pressure.

[0035] The function of the throttle valve 14 is to bypass unloading and adjust the movement speed of the two chambers of the oil cylinder.

[0036] Working principle: When work is required and the fork does not need to move, the first reversing valve plate 3 and the second reversing valve plate 15 are both in the middle position, the oil inlet P is connected to the oil return port T, and the hydraulic oil output by the oil pump 1 flows back to the hydraulic oil tank 17 through the middle oil channel.

[0037] When the forklift fork moves sideways, the second reversing valve plate 15 is in the reversing position. When the pressure oil output by the oil pump 1 is connected to the first working oil port A2 of the second reversing valve plate 15 through the oil inlet P, the pressure oil output by the oil pump 1 passes through the first working oil port A2 of the second reversing valve plate 15 and the second three-way pipe 11 to reach the rodless chamber of the left fork distance adjusting cylinder 8, pushing the piston rod of the left fork distance adjusting cylinder 8 to drive the fork to move to the left. The pressure oil output by the rod chamber of the left fork distance adjusting cylinder 8 reaches the rod chamber of the right fork distance adjusting cylinder 7 through the first three-way pipe 6, pushing the piston rod of the right fork distance adjusting cylinder 7 to drive the fork to move to the left. The pressure oil output by the rodless chamber of the right fork distance adjusting cylinder 7 flows back to the oil tank through the third three-way pipe 12 and the second working oil port B2 of the second reversing valve plate 15, realizing the left side movement of the fork. Similarly, when the pressure oil output by the oil pump 1 is connected to the second working oil port B2 of the second reversing valve plate 15, the pressure oil output by the oil pump 1 passes through the second working oil port B2 of the second reversing valve plate 15, the third three-way pipe 12, and reaches the rodless chamber of the right fork distance adjusting cylinder 7, pushing the piston rod of the right fork distance adjusting cylinder 7 to drive the fork to move to the right, the pressure oil output by the rod chamber of the right fork distance adjusting cylinder 7 passes through the first three-way pipe 6 to reach the rod chamber of the left fork distance adjusting cylinder 8, pushing the piston rod of the left fork distance adjusting cylinder 8 to drive the fork to move to the right, and the pressure oil output by the rodless chamber of the left fork distance adjusting cylinder 8 flows back to the oil tank through the second three-way pipe 11 and the first working oil port A2 of the second reversing valve plate 15, realizing the right side movement of the fork. During the left and right side shifting of the fork, when one cylinder has reached its stroke, the other cylinder has not yet reached its stroke. For example, during the left side shifting, the right fork distance adjusting cylinder 7 has reached its stroke, but the left fork distance adjusting cylinder 8 has not yet reached its stroke. Because the rod chambers of the left and right fork distance adjusting cylinders are connected to the third working oil port C1 of the logic control valve block 4 and the first hydraulically controlled one-way valve 5, and the first hydraulically controlled one-way valve 5 has no pressure oil and is in a reverse cut-off state, it can prevent the other cylinder from moving due to leakage in the valve block.

[0038] When the forklift fork needs to adjust the distance of the double forks, the first reversing valve plate 3 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 reversing valve plate 3, the pressure oil output by the oil pump 1 passes through the first working oil port A1 of the first reversing valve plate 3 and reaches the first working oil port V1 of the logic control valve block 4, and is divided into six paths through the first working oil port V1, one path reaches the working port a of the throttle valve 14; one path reaches the working oil port D of the first two-way hydraulic lock 5; one path reaches the inlet c of the overload valve 9; one path reaches the oil outlet f of the second overload valve 16, and the second overload valve 16 is reversely cut off. The other two paths enter the control oil circuits of the second hydraulically controlled one-way valve 10 and the third hydraulically controlled one-way valve 13 respectively, so that the second hydraulically controlled one-way valve 10 and the third hydraulically controlled one-way valve 13 are reversely conducted. The pressure oil reaches the working oil port D of the first two-way hydraulic lock 5, and reaches the rod chambers of the right fork distance adjusting cylinder 7 and the left fork distance adjusting cylinder 8 respectively through the third working oil port C1 of the logic control valve block 4 and the first three-way pipe 6, pushing the piston rod of the right fork distance adjusting cylinder 7 to drive the fork to move to the left, and pushing the piston rod of the left fork distance adjusting cylinder 8 to drive the fork to move to the right. Since the second hydraulically controlled one-way valve 10 and the third hydraulically controlled one-way valve 13 control the oil passage through the pressure oil, and conduct in the reverse direction, the pressure oil output from the rodless chamber of the right fork distance adjustment oil cylinder 7 flows back to the oil tank through the third three-way pipe 12, the fifth working oil port C3 of the logic control valve block 4, the working oil port F of the third hydraulically controlled one-way valve 13, the second working oil port V2 of the logic control valve block 4, and then through the second working oil port B1 of the first reversing valve plate 3; the pressure oil output from the rodless chamber of the left fork distance adjustment oil cylinder 8 flows back to the oil tank through the second three-way pipe 11, the fourth working oil port C2 of the logic control valve block 4, the working oil port E of the second hydraulically controlled one-way valve 10, the second working oil port V2 of the logic control valve block 4, and then through the second working oil port B1 of the first reversing valve plate 3. The simultaneous retraction of the double forks is realized. The function of the first overload valve 9 is to prevent the impact caused by excessive pressure in the rod chambers of the left and right fork distance adjustment oil cylinders during the simultaneous retraction process. The function of the throttle valve 14 is to unload the load (unload the oil) in the bypass so as to adjust the speed of the contraction movement of the two oil cylinders.

[0039] When the forklift forks need to adjust the distance of the double forks, the first reversing valve plate 3 is in the reversing position. When the pressure oil output by the oil pump 1 is connected to the second working oil port B1 of the first reversing valve plate 3, the pressure oil output by the oil pump 1 passes through the second working oil port B1 of the first reversing valve plate 3 and reaches the second working oil port V2 of the logic control valve block 4, and is divided into six paths through the second working oil port V2, one path reaches the working port b of the throttle valve 14; one path reaches the control oil path of the first hydraulically controlled one-way valve 5, so that the first hydraulically controlled one-way valve 5 is reversely conducted; one path reaches the working oil port F of the third hydraulically controlled one-way valve 13; one path reaches the working oil port E of the second hydraulically controlled one-way valve 10; one path reaches the outlet d of the first overload valve 9, and the first overload valve 9 is reversely cut off. The pressure oil reaches the working oil port F of the third hydraulic control check valve 13, and then reaches the rodless chamber of the right fork distance adjustment cylinder 7 through the fifth working oil port C3 of the logic control valve block 4 and the third three-way pipe 12, pushing the piston rod of the right fork distance adjustment cylinder 7 to drive the fork to move to the right; the pressure oil reaches the working oil port E of the second hydraulic control check valve 10, and then reaches the rodless chamber of the left fork distance adjustment cylinder 8 through the fourth working oil port C2 of the logic control valve block 4 and the second three-way pipe 11, pushing the piston rod of the left fork distance adjustment cylinder 8 to drive the fork to move to the left. After the pressure oil output from the rod chambers of the right fork distance adjustment cylinder 7 and the left fork distance adjustment cylinder 8 merges with the first three-way pipe 6, it flows back to the oil tank through the third working oil port C1 of the logic control valve block 4, the working oil port D of the first hydraulic control check valve 5, the first working oil port V1 of the logic control valve block 4, and the first working oil port A1 of the first reversing valve plate 3. The double forks are opened at the same time. The function of the second overload valve 16 is to prevent the impact caused by the excessive pressure of the rodless chamber of the left and right fork distance adjustment cylinders during the simultaneous opening process. The function of the throttle valve 14 is to adjust the opening movement speed of the two cylinders to complete the work.

[0040] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulic logic control system for a side shifting distance adjusting fork, comprising an oil pump (1), a safety valve (2), a first reversing valve plate (3), a logic control valve block (4), a first hydraulically controlled non-return valve (5), a first three-way pipe (6), a right fork distance adjusting oil cylinder (7), a left fork distance adjusting oil cylinder (8), a first overload valve (9), a second hydraulically controlled non-return valve (10), a second three-way pipe (11), a third three-way pipe (12), a second hydraulically controlled non-return valve (13), a throttle valve (14), a second reversing valve plate (15) and a second overload valve (16); The logic control valve block (4) comprises a second hydraulically controlled one-way valve (10), a second hydraulically controlled one-way valve (13), a throttle valve (14) and a second overload valve (16), and the second hydraulically controlled one-way valve (10), the second hydraulically controlled one-way valve (13), the throttle valve (14) and the second overload valve (16) are connected via a pipeline; The first reversing valve plate (3) is connected to the second reversing valve plate (15), the oil pump (1) is connected to the second overload valve (16), and the oil pump (1) is also connected to the oil tank (17) through the safety valve (2). The first reversing valve plate (3), the second reversing valve plate (15) and the oil tank (17) are connected. The first reversing valve plate (3) is connected to the logic control valve block (4), the logic control valve block (4) is connected to the first three-way pipe (6), the first three-way pipe (6) is connected to the right fork distance adjustment cylinder (7), and the first three-way pipe (6) is also connected to the left fork distance adjustment cylinder (8).

2. A hydraulic logic control system for a side shift fork according to claim 1, characterized in that: The second three-way pipe (11) is in communication with the second reversing valve plate (15), and the second three-way pipe (11) is also in communication with the logic control valve block (4) and the left fork distance adjusting cylinder (8). The second reversing valve plate (15) is in communication with the third three-way pipe (12), and the third three-way pipe (12) is in communication with the logic control valve block (4) and the right fork distance adjusting cylinder (7).

3. A hydraulic logic control system for a side shift fork according to claim 2, characterized in that: The first overload valve (9) is in communication with the logic control valve block (4), and the second overload valve (16) is in communication with the logic control valve block (4).

4. A hydraulic logic control system for a side shifting fork according to claim 3, characterized in that: The logic control valve block (4) is controlled to communicate via a second hydraulically controlled one-way valve (10) and a second hydraulically controlled one-way valve (13).

5. A hydraulic logic control system for a side shifting fork according to claim 4, characterized in that: The first overload valve (9) and the second overload valve (16) are used to limit the maximum pressure of the rod chambers of the left and right fork distance adjustment cylinders and to prevent impact caused by excessive pressure.

6. A hydraulic logic control system for a side shifting fork according to claim 5, characterized in that: The throttle valve (14) is used for bypass unloading and regulating the movement speed of the two chambers of the oil cylinder.

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