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Mechanical Actuators
A Leader in Heat Transfer Components, Products and Systems

Upright Rotating

If you need to lift a heavy load with minimal force, there may be no better solution than a machine screw mechanical actuator. C.H. Bull is your #1 resource for mechanical actuators, with a selection of reliable, high performance machine screw actuators from Duff Norton. Duff Norton’s upright rotating machine screw mechanical actuators bring dependability and durability to any load-lifting application.

Request a quote on an upright rotating machine screw actuator, or contact us to learn more.

Duff Norton Upright Rotating Machine Screw Actuators

Duff Norton manufactures upright rotating machine screw mechanical actuators in capacities from 500 lbs. to 250 tons. They are highly customizable, making it easy to find a device that provides ideal performance for your unique application (see below).

Duff Norton machine screw actuators can be operated manually, or via electric, hydraulic, or pneumatic gear motors. They can be used solo, in pairs, or in multiple-actuator arrangements, should your application require. Most models operate at a uniform speed, which allows actuators with different capacities to be used simultaneously on the same load.

Most Duff Norton upright rotating machine screw actuators are self-locking—they’ll hold heavy loads in place indefinitely. They can be used to push, pull, or apply pressure, and can be used as linear actuators. They’re furnished with standard raises in 1” increments; total raise up to 20’ is available.

To meet your application requirements, four different screw end options are available: plain ends, clevis ends, threaded ends, and top plates. Optional limit switches can be used to manage vertical travel (up or down).


•    Positive, mechanical positioning
•    Precision positioning within thousandths of an inch
•    Uniform lifting speed
•    Optional anti-backlash
•    Customizable (see below)

We also offer inverted rotatingupright translating, and inverted translating machine screw mechanical actuators, as well as Duff Norton ball screw actuators.

Customizable to Meet Your Application Requirements

To meet your unique performance requirements, C.H. Bull can provide a customized upright rotating machine screw actuator. A variety of features can be customized to your specifications, including:

•    Stroke length
•    Lifting capacity
•    Screw end type
•    Motor type
•    Limit switch
•    and more

Request a quote on an upright rotating machine screw mechanical actuator. Contact C.H. Bull for more information on these or any of our quality products.

Selecting the Right Mechanical Actuator for Your Needs

Step 1: Define operating parameters such as total load, load per actuator (if using multiple actuators), lifting speed, total required travel, load type, and ambient working temperature.

Step 2: Determine which style of actuator best suits your application. Several factors should be considered when choosing between a machine screw actuator or a ball screw actuator. Machine screw actuators are inherently load-holding and are preferred for applications which experience constant vibration. Ball screw actuators are faster, more efficient, and require lower motor horsepower to lift an equivalent load.

Step 3: Calculate the necessary actuator performance. Choose an actuator with a capacity greater than the load it will lift. Then, use the formulae below to determine the performance requirements.

For loads that are greater than 25% of the actuator’s capacity, torque should be considered proportional to the load.

A) Actuator torque (in.-lbs.) = Actuator load (lbs.) x worm torque at full load

Actuator capacity (lbs.)
(For loads less than 25% of the actuator’s capacity, add “Worm torque at no load” to this equation to account for frictional losses.)

Calculate the actuator’s input RPM. (WARNING: Shaft input should never exceed 1,800 RPM.)

B) Input RPM = Desired lifting speed (in./min.) x turns of worm for 1” lift
Calculate actuator input HP.

C) Actuator input HP = Actuator torque (in.-lbs.) x RPM

Compare the actuator’s maximum HP to the required input HP. If the required HP exceeds the specified maximum, you’ll need an actuator with a higher HP rating.

If you’re using a gear reducer, multiply the motor HP by the reducer’s efficiency to determine reducer output (actuator input) HP.

If you’re using a multi-actuator configuration with two or more mechanical actuators shaft-driven by a single motor or gear reducer, calculate the total input HP requirements of all actuators. If you’re using a mitre gear box, calculate for 2% power loss for every 90° turn in the power path.

Step 4: Determine the required actuator configuration, taking into account capacity, desired lifting speed, and duty cycle requirements.

Step 5: If working with an unattached or unguided load the mechanical actuator must be configured so that the lifting screw extends with actuator movement. To prevent rotation of the translating screw, Duff Norton actuators are supplied with a keyed shell and screw (for machine screw actuators) or a square nut inside a square cover pipe for the end of the lifting screw (for ball screw actuators).

Step 6: Verify actuator selection. Double-check the total load and travel requirements of your application. Double-check the ratio, capacity, and speed of your chosen actuator. Determine which end fitting—plain end, threaded end, clevis end, or top plate—is best for your needs.

Safety Warnings

Actuator input RPM should never exceed 1,800 RPM.

Never exceed your actuator’s static capacity or dynamic capacity.

Never exceed the actuator’s specified horsepower limits. If maximum HP must be exceeded, reduce lifting speed, select a different actuator ratio, or consider a model with higher capacity of greater lifting efficiency.

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