Abstract: A balance weight system for a unit includes a cylinder and a piston rod having a first end secured to the unit to move therewith. The piston rod further includes a second end with a piston head slidably received in the cylinder and separating the cylinder into a lower chamber for containing hydraulic oil and an upper chamber for containing air. A tank includes hydraulic oil contained in a lower part thereof and a working gas contained in an upper part thereof. A tube has a first end in the hydraulic oil in the lower part of the tank and a second end communicated with the lower chamber of the cylinder. The working gas exerts a pressure on the hydraulic oil to supply the piston rod with a force sufficient to uphold the unit. A motor is provided for moving the unit in a vertical direction.

Abstract: An air lifting and balancing unit including a cylinder, a piston in the cylinder, a ball screw affixed to the piston, a ball nut mounted for rotation on the ball screw, a drum mounted on the ball nut, a chain driven by the drum, and centrifugally actuated brakes mounted on the drum for stopping rotation of the drum when the drum exceeds a predetermined acceleration either due to a loss of load or to a loss of air pressure applied to the piston, and a pneumatic circuit in communication with the cylinder for providing air pressure thereto which applies a force on the piston which is at a substantially constant incremental value in opposition to the force exerted by the load applied to the piston through the chain and the drum and the ball screw regardless of variations in said air pressure to thereby cause the speed of the chain to remain substantially constant.

Abstract: A control device for a balancer includes a load detector for determining the torque exerted on a driving screw attributable to the load driven and supported thereby. A fluid pressure control device increases or decreases the pressure input to a balancing torque generator in response to the detected load at a given time instant.