1. Reasons for improvement
The hydraulic circuit of a type of 14t forklift gantry is controlled by 4 directional valves, of which 2 directional valves control the action of the gantry attachment, 1 directional valve controls 1 gantry lifting action, and 1 directional valve controls 1 Tilt action of mast. The two-piece reversing valve that controls the action of the mast attachment is often used for fork fork lateral movement and pitch adjustment. When the forklift mast needs to be fitted with complex attachments (such as adding an additional attachment cylinder), these two pieces of reversing valves The valve can not meet the needs of working conditions. If a directional valve with a larger number of pieces is used, it will not only increase the production cost, but also require major changes to the existing design. The hydraulic circuit of the improved front mast is shown in Figure 1.
2. Improvement methods
In order to solve the problem that the existing 4 pieces of directional valves cannot meet the complicated attachments, we decided to improve the hydraulic circuit of the gantry, that is, add 1 to the 4th piece of directional valve pipeline of the existing directional valve group Two-position six-way solenoid valve 3 to increase the action requirement of one attachment cylinder 5. The hydraulic circuit of the improved rear mast is shown in Figure 2. The pipelines (2, 4) in FIG. 2 are used to connect the two-position six-way solenoid valve 3 and the attachment cylinder 5.
Figure 2Improved hydraulic circuit of the rear gantry 1. Directional valve group 2, 4, 8 pipeline 3. Two-position six-way solenoid valve 5. Attachment cylinder 6, 7. Side shift cylinder
3. Improved working process
By manipulating the spool of the fourth reversing valve on the left, pressure oil can be input into the two-position six-way solenoid valve through line 2. The pressure oil enters the pipeline 8 through the two-position six-way solenoid valves C3 and C4 oil ports, and then enters the side shift cylinders (6, 7), and pushes the side shift cylinders (6, 7) to realize the side shift of the fork. If the pipeline connection mode of the side shift cylinder (6, 7) is changed, other attachment actions can be realized.
Press the two-position six-way solenoid valve control switch, the solenoid valve spool will move to the left position. At this time, the spool of the left side (4th piece) reversing valve is operated. The pressure oil enters the pipeline 4 through the two-position six-way solenoid valves C1 and C2 oil ports, and then enters the attachment cylinder 5 to push the attachment cylinder 5 to move The actions required to complete the complex attachment of the mast (such as clamping, rotating, pushing out, etc.). Loosen the two-position six-way solenoid valve control switch, the solenoid valve spool will move to the right position, and can complete the side shift cylinder (6, 7) action.
4. Improve the effect
The improved hydraulic circuit of the gantry adds a two-position six-way solenoid valve and corresponding pipelines, and adds a set of actuating circuits for attachment cylinders without increasing the valve pieces of the directional valve. The improved hydraulic circuit of the gantry has good performance, easy installation, reliable use, easy maintenance, and low cost. It has been applied to 14t forklifts in batches, and user feedback is good.
