Duff-Norton Screw Jacks

Screw Jacks - 1/4 to 350 Ton

1/4 to 350 ton capacity. Acme screw jacks offer positive mechanical action, precise positioning, and uniform lifting speeds. Standard configurations include upright or inverted units with translating or rotating lifting screws, and top plate, threaded, or clevis ends.

Duff-Norton offers a complete line of both standard and custom engineered machine screw actuators for applications up to 350 tons.

• Machine Screw Actuators can be controlled accurately for positioning within thousandths of one inch.
• Models featuring higher gear ratios are inherently load holding as long as the actuator is not subject to vibration
• Since many actuators feature the same gear ratios different capacities can be used in the same application to lift unevenly distributed loads with uniform speeds.
• All actuators are designed and built to be positive acting, for accurate response to motive power.

Screw Jacks - 1/4 to 350 Ton

Essentials Platform Actuators - 1/8-to-10-ton load capacity. Establishing a strong foundation.

The new Essentials Platform is built on Duff-Norton’s history of reliable products and provides customers with cost effective options to meet their fundamental needs.

• Robust, cost effective solution for use in many applications
• Drop-in compatibility with many competitors screw jacks - refer to pages 5 - 7 in the Essentials Platform Design Guide for bolt pattern drawings
• Precision gearing and ACME screw construction limits backlash to a max of .015 inches
• Limited screw lengths and options make the Essentials Platform easy to specify and configure
• Developed with safety in mind - Minimum column strength of the screw is 2x higher than the screw jack’s lifting capacity. All reported column strengths are for a 6 inch screw length in a fixed-free arrangement.

Screw Jacks - 1/4 to 350 Ton

1/4-to-250-ton capacity. Anti-backlash actuators reduce vertical backlash resulting in smooth, precise operation and minimal wear. Backlash occurs when the motor driving an actuator reverses its load direction. When the actuator is under load, the lifting screws threads are supported by the worm gears threads. The anti-backlash nut, pinned by the worm gear and adjusted downwards by the shell cap, forces the bottom thread surfaces against the upper thread surfaces of the lifting screw. Thus, backlash between the lifting screw and worm gear threads is reduced to a minimum.

• Duff Norton's anti-backlash design features a separate anti-backlash nut capable of reducing actuator backlash to less than 1 thousandths.
• Anti-backlash actuators can lock and reliably hold a load, thereby eliminating the need for brake motors required for some applications.
• Duff-Norton developed the anti-backlash actuators to reduce screw-to-nut backlash to an absolute minimum.
• As wear occurs, the actuator can be easily adjusted, without any disassembly, to return the backlash to its’ original minimum value.
• Available with standard, optional, & numeric ratios.
• Available in stainless steel for most capacities.

2-to-100-ton load capacity. Stainless Steel Screw Jacks offer positive mechanical action, precise positioning, and uniform lifting speeds. Standard configurations include upright or inverted units with translating or rotating lifting screws, and top plate, threaded, or clevis ends. Duff-Norton offers a complete line of both standard and custom engineered machine screw actuators for applications up to 350 tons.

• From 2 ton to 350 ton models.
• Sealed gear cavity keeps water and other contaminants out.
• Upright and inverted rotating screw models with traveling nut available.
• Available with keyed lifting screws for translating screw models.
• Can be retrofitted into applications where Duff-Norton non-stainless steel actuators have been previously used.
• Closed heights, lifting screw ends, worm shaft extensions, lifting screw thread pitches, materials, stop nut, bellows boot.

Screw Jacks - 1/4 to 350 Ton

The Anode heavy-duty screw jack has been modified for high temperature loads found in the alumina smelting industry.

The worm gears are made of wear resistant bronze and are up to 40% larger than our standard versions. This anode screw jack also contains heavy duty seals that protect against very abrasive alumina dust. Anode screw jacks use only heat-treated alloy steel worms.

These heavy-duty screw jacks have a large overload capacity to handle the side loading stresses caused by the thermal expansions and contractions of the frames. They are also built to take the compressive overloads caused by occasional high jacking of the frames and frozen pots.

• Anode Jacks specially designed for use in the Aluminum Industry
• Wear resistant bronze worm gears are up to 40% larger than our standard versions.
• Large bearings with heavy duty seals keep out abrasive dust.
• Anode Jacks use only heat-treated alloy steel worms for improved tensile strength.
• Large overload capacity to handle the side loading stresses caused by the thermal expansions and contractions of the frames. Withstand compressive overloads caused by occasional high jacking of the frames and frozen pots

Screw Jacks - 1/4 to 350 Ton

Up to 1,000 lbs. capacity. Duff-Norton miniature screw jacks allow for extremely fine adjustments. These small screw jacks are equipped with anti-backlash nuts to minimize vertical backlash between the screw and worm gear nut. The manual operation is accomplished with an easy-to-use hand knob. The dial indicator is protected by a removable clear plastic cover.

• Micro-Miniature actuators allow for extremely fine adjustments.
• These Micro-Miniatiure actuators are equipped with anti-backlash nuts to minimize vertical backlash between the screw and worm gear nut.
• The manual operation is accomplished with an easy-to-use hand knob.
• Dial indicators available upon request. The dial indicator is protected by a removable clear plastic cover.
• Available with sealed 316 stainless steel shell cap, housing, worm and lifting screw.
• Corrosion-resistant materials

Screw Jacks - 1/4 to 350 Ton

1/2-to-50-ton capacity. Ball Screw Jacks provide high efficiency and high speed in one linear positioning package. These actuators come in many standard models, or can be custom designed for any application up to 50 tons. The positive action of the low friction ball screw and nut design provides longer life at load and requires less power to achieve a specified thrust. Ball screw actuators can be used individually, in tandem or as part of a larger mechanical system. With lifts up to 20 feet, Duff-Norton Ball Screw actuators offer the perfect solution to many linear positioning applications.

• Requires less power by providing positive mechanical action.
• Long predictable ball screw and ball nut life.
• Ball screw actuators can be used individually, in tandem or as part of a larger mechanical system.
• Move loads and apply force more efficiently than other mechanical actuators.
• Ball screw jacks reliably handle full loads in tension or compression.
• Ball screws permit faster operation and longer life under heavy loads.

Screw Jacks - 1/4 to 350 Ton

3,500 to 27,000 pound load capacity. Continuous Duty Cycle actuators are specifically designed for continuous operation. The gear set in these actuators operate in an oil bath for thermal efficiency and long life. The shell is made of a finned aluminum for better cooling properties. Additionally, the Duff-Norton ball screw system increases these models efficiency.

• The gear set in the Continuous Duty Cycle actuator operates in an oil bath for thermal efficiency and long life.
• Designed to run at a worm speed of 1750 rpm fully loaded.
• Efficient design needs less power to run.
• Sand-cast aluminum housings for added heat dissipation.
• The shell is made of a finned aluminum for better cooling properties.
• Available with C-Face Motor Adaptors and Reducers.

Metric Anti-backlash Actuators 5 to 500 kN

5-to-500-kN load capacity. Metric Anti-backlash actuators reduce vertical backlash resulting in smooth, precise operation and minimal wear. Backlash occurs when the motor driving an actuator reverses its load direction. When the actuator is under load, the lifting screws threads are supported by the worm gears threads. The anti-backlash nut, being pinned by to the worm gear and being adjusted downwards by the shell cap, forces the bottom thread surfaces against the upper thread surfaces of the lifting screw. Thus backlash between the lifting screw and worm gear threads is reduced to a minimum.

• Anti-backlash nuts reduce worm gear wear. They also act as additional load safety devices when the worm gear has become worn.
• The anti-backlash nut, being pinned to the worm gear and adjusted downwards by the shell cap, forces the bottom thread surfaces against the upper thread surfaces of the lifting screw. Thus backlash between the lifting screw and worm gear threads is reduced to a minimum.
• The Duff Norton Anti-backlash design features a separate anti-backlash nut and reduces actuator backlash to less than 1 thousandths.
• Metric Anti-backlash actuators reduce vertical backlash resulting in smooth, precise operation and minimal wear.

Metric Machine Screw Actuators 5 to 200 kN

5 to 500 kN load capacity. Metric Machine Screw Jacks are manufactured to the same high quality standards and include all of the same features and benefits as the standard line of actuators. Metric Machine Screw Actuators offer positive mechanical action, precise positioning, and uniform lifting speeds. Standard configurations include upright or inverted units with translating or rotating lifting screws, and top plate, threaded, or clevis ends.

• Mounting dimensions in millimeters. All metric fasteners on machine screw units. Metric bolt centers. Metric screw diameters with trapezoidal threads.
• Standard configurations include upright or inverted units with translating or rotating lifting screws, and top plate, threaded, or clevis ends.
• Duff-Norton metric machine screw cctuators offer positive mechanical action, precise positioning, and uniform lifting speeds.
• Since many actuators feature the same gear ratios different capacities can be used in the same application to lift unevenly distributed loads with uniform speeds.