HYDRAULIC/PNEUMATIC CYLINDER AS BALANCER UNITS

摘要

An industrial robot has two linkages connected with a rotary joint. Gravity imposes a torque on the joint. A counterbalancing unit connects the two linkages to each the other to compensate for the gravity-caused torque. The unit has a cylinder with two chambers. A piston in the cylinder has one end connected to the rotary joint and seals the two chambers against each other. Hydraulic fluid is in at least one of the two chambers and one or more instances of compressible material are in the hydraulic fluid. Movement of the rotary joint in a predetermined direction causes the piston to move and compress the compressible material and increase the cylinder pressure to create a force on the piston rod in a direction opposite to a direction of the piston movement.