Columbus McKinnon Corporation Screw Jacks Screw Jacks

Duff-Norton screw jacks are mechanical actuators designed for lifting, positioning, aligning, and holding loads in industrial applications, with capacities ranging from 500 lb to 350 tons. They are available in imperial and metric configurations, including machine screw, ball screw, anti-backlash, and stainless steel variants, and support both manual and motorized operation. Motorized models include IEC B-face motor adapters compatible with 25 kN to 300 kN G-series actuators. The actuators can be synchronized in multi-unit arrangements with efficiency ratings of 80% to 95% depending on the number of units. Machine screw and anti-backlash models with 24:1 and 25:1 gear ratios are self-locking; ball screw models require external braking. Maximum input speed is 1800 RPM, and continuous duty operation is supported by the 7500 Series oil-lubricated models. Dimensions and mounting configurations are standardized, with inverted screw models offering varied closed heights based on lift range and capacity.