Four-Bar Actuator Calculator

How the closed four-bar lifting linkage works

All four link lengths close the linkage at every sampled pose. Actuator effort follows virtual work using payload, coupler and link gravitational energy. The payload location is a percentage along the coupler. Only the selected continuous assembly branch is solved; colliding links and flexible joints are not modeled.

Measurements for this application

Measure all four pivot-to-pivot lengths and the actuator pin on the output link. Select the assembled branch.

• Record distance between fixed pivots, input link length, coupler link length, output link length, start angle. Measure between pivot or mounting-pin centers.
• Account for payload / supported load, coupler / moving platform weight, combined moving link weight, additional resisting torque. Use the heaviest permitted operating condition.
• Enter the actual motion limits and check the mechanism at both ends and through the full path.

Choosing an actuator for closed four-bar lifting linkage

The calculator checks the required force, stroke and mounting length before displaying variants. Super Duty actuators take priority, followed by Utility and C-Series where their dimensions and ratings fit. Industrial actuators take priority above 450 lbf of moving load or required actuator force; feedback Micro Pen actuators take priority for the humanoid finger.

Compare exact variants, set travel limits for any unused stroke, and verify the controller, duty cycle, environment and mounting details. Save the design or download its engineering brief to keep your measurements and results together.

What does this calculator solve?

Closed four-bar lifting linkage is solved along the entered start-to-end path. The animation follows those measurements and the force plot shows the demand through the move. The stated model assumptions define which parts of the real mechanism are included.