HYDRAULIC TABLE

A hydraulic lift table raises and lowers the load when hydraulic fluid is forced into or out of the hydraulic cylinder. As hydraulic fluid is forced into a cylinder, the cylinder strokes outward forcing the scissor legs apart.

Since one end of both the inner and outer legs are connected to the base and platform, the platform rises vertically as the scissors legs open. The free end of the scissors legs are fitted with rollers that run in the base. Any time a lift table is raised, it is being supported by a column of fluid. The lift table remains in a raised position because the fluid is held in the cylinder by a simple check valve. A lift table’s up speed is a function of the hydraulic pump and the motor that is turning it. The desired up speed and capacity to be lifted determine the amount of work the motor has to do, thus the horsepower required. If a lift table needs to move faster, it will take more horsepower. If a lift table has to have greater capacity, it will also take more horsepower.

The lift table is lowered by opening a down valve that allows fluid out of the cylinder at a controlled rate. This down valve is solenoid operated and a “normally closed” type valve, which means it stays closed until the electric solenoid is actuated. This feature prevents the lift table from lowering if there were a power failure. When the solenoid opens the down valve, the fluid returns to the reservoir.

The down speed of a lift table is a function of controlling how fast the fluid is allowed to leave the cylinder. This is done with a flow control (FC) valve. The FC valve is pressure compensated, which means it regulates the flow to a predetermined range whether the lift is loaded or empty. These FC valves are fixed rate or non-adjustable and typically the lift table’s down speed is matched to lift table’s up speed.

I have designed this project in Solidworks and the sole purpose of this project was to indulge my knowledge in tools and machines used in the industry.

These are the parts of the Shock Absorber along with their function in caption.