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.
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 - Metric Machine Screw Actuators - Capacities 5 to 500 (kN)
|Lifting Screw||Diameter (mm)||16||20||30||38||52||58||65||95||115|
|Worm Gear Ratios||Standard||5:1||5:1||6:1||6:1||8:1||8:1||8:1||10-2/3:1||10-2/3:1|
|Optional No. 1||—||20:1||24:1||24:1||24:1||24:1||24:1||32:1||32:1|
|Optional No. 2||—||—||12:1||12:1||—||—||—||—||—|
|Travel per Worm Turn (mm)||Standard||0.60||1.00||1.00||1.50||1.50||1.50||1.50||1.50||1.50|
|Optional No. 1||—||0.25||0.25||0.38||0.50||0.50||0.50||0.50||0.50|
|Optional No. 2||—||—||0.50||0.75||—||—||—||—||—|
|Worm Torque at No Load (N-m)||Standard||0.23||0.56||0.56||1.13||2.26||2.26||3.39||5.65||11.3|
|Optional No. 1||—||0.56||0.56||1.13||2.26||2.26||3.39||5.65||11.3|
|Optional No. 2||—||—||0.56||1.13||—||—||—||—||—|
|Maximum Input Power (kW)||Standard||0.25||0.37||1.49||2.98||3.73||3.73||3.75||6.00||11.2|
|Optional No. 1||—||0.198||0.37||0.56||1.12||1.12||1.12||1.86||4.50|
|Optional No. 2||—||—||0.56||1.49||—||—||—||—||—|
|Worm Torque at Full Load (N-m)||Standard||2.83||7.53||20.10||56.78||117.1||189.2||275.4||505.7||915.5|
|Optional No. 1||—||3.69||9.34||27.06||63.2||101.4||147.7||305.3||520.5|
|Optional No. 2||—||—||12.8||36.65||—||—||—||—||—|
|Efficiency Rating (%)||Standard||16.9||21.1||19.8||21.0||20.4||18.9||17.3||14.2||13.0|
|Optional No. 1||—||10.8||10.7||11.0||12.6||11.8||10.8||7.8||7.6|
|Optional No. 2||—||—||15.5||16.3||—||—||—||—||—|
|Weight with 25mm Raise (kg)||1.04||2.27||7.71||15.88||23.59||29.94||42.18||100||173|
|Weight per Additional 25mm Raise (kg)||0.04||0.13||0.13||0.40||0.63||0.67||1.16||1.65||2.46|
|Key Torque (M-n)||8.48||22.80||76.61||213.37||579.94||943.98||1374.01||2954.25||5746.55|
|Maximum Worm Speed
at Full Load (RPM)
|Optional No. 1||—||491||378||198||169||105||72||58||83|
|Optional No. 2||—||—||418||388||—||—||—||—||—|
|Maximum Load at Full
Horsepower and 1750
|Optional No. 1||
|Optional No. 2||—||—||6.39||12.22||—||—||—||—||—|
|Note: For loads from 25% to 100% of actuator capacity, torque requirements are approximately proportional to the load. Raises, measured in increments
of 25mm, are available up to 6.1 meters, depending on lifting screw diameter and available bar stock length.
Note: Contact customer service for motorized performance.
Key Adaptor Dimensions
|Key Adaptor Dimensions for Metric Anti-backlash Actuators|
|Actuator Capacity (kN)||Upright Actuators||Inverted Actuators|