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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.
Actuator Controls

Actuator Control System

Actuator Control System
Duff-Norton offers constant speed AC Motor Control Systems for machine and ball screw actuators. These new control systems provide the option of jogging-inching, or maintained operation, when specified as part of a Duff-Norton Linear Positioning System. Numerous options are available including short circuit protection, pilot lamps, illuminated push buttons, and loose limit switches, as well as single and three phase power up to 575 VAC. Contact Duff-Norton for all your special control applications needs.

Rotary Limit Switch
Download Rotary Limit Switches
Rotary limit switches can be fitted to all Duff-Norton mechanical actuators 2 ton and larger. Sturdy, compact, and constructed of corrosion resistant materials. Control circuit switches are rated up to 277VAC. Three gear ratios are available to optimize repeatability with different actuator strokes. For more information plus specifications and dimensions, please download our PDF using the link above.

Potentiometer and Transducer
Download Potentiometer and Transducer PDF
The Duff-Norton SKA6200T Series Position Feedback Potentiometer/Transducer is designed to mount on the end of any SKA6000T limit switch. Its active component is a precision potentiometer which may be used as voltage divider to provide a feedback voltage that is proportional to actuator position. For more information plus specifications and dimensions please download our PDF using the link above.

Worm Shaft Encoder
Download Worm Shaft Encoder PDF
The Duff-Norton Digital Encoder and Digital Display is a more advanced way to determine an actuator's position. A digital encoder can be used to provide an extremely precise position signal to devices such as the Duff-Norton SK10006-35 digital display or 3rd party PLC's.
Duff-Norton uses two styles of incremental encoders, with the type used depending on the layout of the actuator. When one end of the actuator worm shaft is accessible, a Hollow Bore style of encoder is used, mounted on the worm. When the worm is not accessible, and the actuator is using a flange-mounted motor, a Ring Kit style encoder can be fitted on the drive motor. For more information plus specifications and dimensions please download our PDF using the link above.

Rotary Counter
Download Rotary Counter PDF
The Duff-Norton Rotary Counter is for actuator customers who are looking for a more economical and easy way to determine an actuator's position. Our counters have been design to match our most common actuator ratios. An operator viewing the reading in the display window will know his actuator's exact position because the counter's display shows stroke to the nearest 1000ths of an inch up to 99 inches of travel. Custom numeric displays are also available.