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SCREW JACK Duff-Norton line of screw jacks (mechanical actuators) includes mechanical actuators (machine screw and ball screw) ranging in size from 1/4 ton to 350 tons, stainless steel machine screw actuators, micro-miniature actuators, high duty cycle actuators, motorized machine screw and ball screw actuators, electric cylinders and motor control systems. Accessories include miter gear boxes, c-face motor adapters, limit switches, transducers, visual and digital position indicators, couplings, ball screws and ball screw systems, and locking rings. Screw Jacks are also used for raising and lowering maintenance platforms, opening and closing air dampers, oven doors and sluice gates, and adjusting tooling machine beds, cable tension and workplace tables. In addition to the broad range of applications and industries for mechanical actuators, they are also used as alternatives to hydraulic and pneumatic systems.
Power Transmission
Duff-Norton offers all of the components necessary to complete your power transmission system, whether it consists of a single actuator or a multiple actuator arrangement. We offer a complete line of accessories to interconnect two or more actuators and provide permanent synchronization. Duff- Norton's Application Engineers can specify shafts, couplings, pillow blocks, and right-angle miter gearboxes to accommodate any layout. Bellows boots to protect actuator screws from dirt and other contaminates are available for all actuators, to increase life and reduce maintenance requirements.

Below are the basic selection of power transmission components that can be utilized to assemble a system. Download the PDFs for further information and specifications.


Power Transmission Components
Duff-Norton's extensive experience in actuator systems can provide you with suggestions for the most economical and reliable method to complete your lifting system. Download the PDF on Transmission components to get diagrams for typical system arrangements and tables that match the parts to their respective actuator sizes to assist selection.


Mitre Boxes
Power transmission systems frequently use multiple actuator arrangements. Such systems commonly use mitre boxes to effectively position and equally distribute loads. As the mitre boxes are supplied with 1:1 gear ratios as standard, all motion is synchronous upon system actuation through the main drive shaft. Our mitre boxes feature a compact design, which eliminates the need for an extended hub. With this design feature the bevel gear is supported by tapered roller bearings on both sides. The result is a higher horsepower rating, increased service-life, improved lubrication, and more flexible mounting compared to other brands.
For more information plus specifications and dimensions please download our PDF using the link above.


Actuator Couplings
Duff-Norton provides three coupling types which have been tailored to specific actuator requirements. Chain Couplings, Jaw Couplings and Full-Flex and Flex-Rigid gear couplings are available. For more information plus specifications and dimensions please download our PDF using the link above.


Connecting Shafts
Duff-Norton's connecting shafts are the solution to a common system operating problem that stems from connecting shafts made from standard steel, which are often bowed or out-of-round. This results in a whipping effect while the system is being run with the connecting shaft working its way loose form the system at high speeds and doing a great deal of damage to the system's equipment. Duff-Norton connecting shafts are furnished with close tolerance Turned, Ground, and Polished steel for smooth rotation.
For more information plus specifications and dimensions please download our PDF using the link above.


Pillow Blocks
Duff-Norton provides a wide assortment of Pillow Blocks designed to operate with our actuators, shafts, and couplings meeting a wide range of system requirements. Pillow Blocks may be used in any shafting configuration for additional shaft support, but are specifically required when the shaft length exceeds the dimensions listed in our shaft selection tables.
For more information plus specifications and dimensions please download our PDF using the link above.


Flange Blocks
Duff-Norton provides a wide assortment of Flange Blocks designed to operate with our rotating type Machine Screw, Ball Screw, and Continuous Duty actuators. Flange Blocks lock on to the end of the rotating screw, and can then be bolted on to the machine or fixture. This ensures that the load being carried by the actuator's lifting nut is properly guided.
For more information plus specifications and dimensions please download our PDF using the link above.


Bellows Boots
Duff-Norton highly recommends the use of a bellows boot for most actuator applications. Duff-Norton can provide bellows boots for the most stringent application requirement. Bellows Boots protect the lifting screw from dust, dirt, moisture, and corrosive contaminants.
For more information plus specifications and dimensions please download our PDF using the link above.