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How To Buy
IMSJ_Actuator
IMSJ_Actuator

Machine (Acme) Screw Jacks

Mechanical Actuators - 1/4 to 350 Ton

IMSJ_Actuator
IMSJ_Actuator
1/4 to 350 ton capacity. Machine (Acme) 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.
Duff-Norton offers a complete line of both standard and custom engineered machine screw actuators for applications up to 350 tons.
Machine Screw Actuator Product Sheet 1/4 Ton Machine Screw Dimensions 1/2 Ton Machine Screw Dimensions 1 Ton Machine Screw Dimensions 2 Ton Machine Screw Dimensions 3 Ton Machine Screw Dimensions 5 Ton Machine Screw Dimensions 10 Ton Machine Screw Dimensions 15 Ton Machine Screw Dimensions 20 Ton Machine Screw Dimensions 25 Ton Machine Screw Dimensions 30 Ton Machine Screw Dimensions 50 Ton Machine Screw Dimensions 75 Ton Machine Screw Dimensions 100 Ton Machine Screw Dimensions 150 Ton Machine Screw Dimensions 250 Ton Machine Screw Dimensions Mechanical Actuators (Screw Jacks) Brochure Mechanical Actuators (Screw Jacks) FAQs

Features & Benefits
FEATURES & BENEFITS
Machine Screw Actuators 1/4 ton to 350 ton

Precise Positioning

Machine Screw Actuators can be controlled accurately for positioning within thousandths of one inch.

Self Locking

Models featuring higher gear ratios are inherently load holding as long as the actuator is not subject to vibration

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.

Quick, Sure Operation

All actuators are designed and built to be positive acting, for accurate response to motive power.

Specifications
Performance Table Instructions 
When reviewing and Duff-Norton Actuator Performance Specification Table, as part of the process of selecting the best-suited actuator for your application, there are several important worm-gear ratios to consider.
Standard Ratio - is frequently chosen when higher speeds and efficiency ratings are desired.
Optional Ratio - is frequently chosen when the application requires higher lifting capacities, lower speeds, or to ease the use of a handwheel.
Numeric Ratio - is frequently chosen for applications requiring fine adjustments, higher lifting capacities, lower speeds, the easy use of a handwheel, self locking applications, and also offers the benefit of an even number of worm input turns per inch of stroke.
Specifications - Standard, Optional, and Numeric Ratios - Capacities 25 to 250 Tons
Capacity (Tons) 25 30 35 50 75 100 150 250* —
Max. Speed C-face Driven (in/min) 107.0 107.5 107.0 — — — — —  
Max. Speed Reducer Driven (in/min) 22.2 22.2 22.4 12.2 — — — —  
Dimensional Information 29 29 30 31-32 33 34 35 36  

Lifting Screw
Diameter (in) 3 3 3-3/4 4-1/2 5 6 7 9  
Pitch (Std. & Opt.) 0.666 0.666 0.666 0.666 0.666 0.750 1.000 1.000  
Pitch (Numerical) 0.320 0.320 0.320 0.320 — — — —  
Type ACME ACME ACME Mod.
Sq.		 Mod.
Sq.		 Mod.
Sq.		 Mod.
Sq.		 Mod.
Sq.		  

Worm Gear Ratios
Standard 10-
2/3:1		 10-
2/3:1		 10-
2/3:1		 10-
2/3:1		 10-
2/3:1		 12:1 12:1 12:1  
Optional No. 1 32:1 32:1 32:1 32:1 32:1 36:1 36:1 —  
Optional No. 2 — — — — — — — —  
Numeric Ratio 32:1 32:1 32:1 32:1 — — — —  

Turns of Worm for 1 inch Stroke
Standard 16 16 16 16 16 16 12 50  
Optional No. 1 48 48 48 48 48 48 48 36  
Optional No. 2 — — — — — — — —  
Numeric Ratio 100 100 100 100 — — — —  

Worm Torque at No
Load (in-lb)
Standard 40 40 50 100 150 200 250 200  
Optional No. 1 40 40 50 100 150 200 250 —  
Optional No. 2 — — — — — — — —  
Numeric Ratio 40 40 50 100 — — — —  

Maximum Horsepower
per Actuator
Standard 8 8 8 15 15 25 25 35  
Optional No. 1 2-1/2 2-1/2 2-1/2 6 6 11 11 —  
Optional No. 2 — — — — — — — —  
Numeric Ratio 2-1/2 2-1/2 2-1/2 6 — — — —  

Worm Torque at Full
Load* (in-lb)
Standard 2220 2640 4000 7500 12000 16000 28110 20000  
Optional No. 1 1401 1685 2400 4200 6601 8600 15500 —  
Optional No. 2 — — — — — — — —  
Numeric Ratio 1500 1800 2411 4040 — — — —  

Efficiency Rating (%)
Standard 22.4 22.4 17.4 13.3 12.4 12.4 14.2 8.0  
Optional No. 1 11.8 11.8 9.7 7.9 7.5 7.7 8.6 —  
Optional No. 2 — — — — — — — —  
Numeric Ratio 5.3 5.3 4.6 3.9 — — — —  

Key Torque (in-lb)
Std. & Opt. 1 & 2 14000 16800 26500 47110 73000 118200 216000 423300  
Numeric Ratio 11474 13770 18561 30970 — — — —  

Maximum Worm Speed
at Full Load (RPM)
Standard 227 190 126 126 79 98 56 110  
Optional No. 1 112 94 66 90 57 81 45 —  
Optional No. 2 — — — — — — — —  
Numeric Ratio 105 87 65 94 — — — —  

Maximum Load at Full
Horsepower and 1750
RPM (lb)
Standard 5691 5691 4220 5949 4939 8865 7003 26780  
Optional No. 1 1839 1839 1193 2831 1537 4670 2875 —  
Optional No. 2 — — — — — — — —  
Numeric Ratio 1714 1714 1187 2946 — — — —  

Maximum Load at Full Horsepower and 1750
RPM (lb)
160 160 240 410 650 1200 1350 2700  

Weight per Add.1 inch Stroke (Raise) (lb)
2.5 2.5 3.7 5.5 6.5 9.0 12.6 23.0  

*Duff Norton has provided special actuators rated at 300 tons and 350 tons for certain applications. Actuators at these capacities are provided under specific Duff Norton / customer agreement as to the actuator’s performance parameters. Please contact our Application Engineering group for more information.

Note: All actuator units can be supplied with standard raises up to 24 inches. Special raises up to 20 feet are available upon request. Closed height dimensions may increase for actuators supplied with bellows boots.

Models

Machine Screw Actuator Cut-Away Diagram
MachineScrewDiagram.jpg
  • Because the Duff-Norton machine screw mechanical actuator is produced in many standard models with a wide range of capacities, there is a standard model for almost any requirement. Models can be furnished to 350 Tons capacity.
  • Operated manually or by means of gear motors, machine screw actuator models can be used singly, in tandem or in multiple arrangements.
  • Since most capacities have a uniform lifting speed, added economy can be realized in raising unevenly distributed loads by operating the different capacities in union.
  • Most Duff-Norton machine screw actuator models with higher ratios are self-locking and will hold heavy loads in position indefinitely without creep.
  • They can be used to push, pull, apply pressure and as linear actuators. They are furnished with standard raises in increments of 1 inch.
  • Depending upon size and type of load, models are available with raises up to 20 feet.

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