Machine Screw Jacks - Notes
- The recommended maximum speed is 1,800 rpm provided that the recommended horsepower and temperature are not exceeded.
- Input torque is shown as torque to lift one pound of load. Starting Torque is 100% greater than torque shown. For loads less than 25% of rated loads add tare drag torque.
- Maximum allowable horsepower ratings are based on a 25% duty cycle. For operation at higher duty cycles or repeated use over any segment of the total travel, temperature must be monitored and remain less than 200°F.
- Overload capacity of the Machine Screw Jack is as follows: 10% for dynamic loads, 30% for static loads.
- Machine Screw Jacks having gear ratios between 20:1 and 32:1 are self-locking and will hold loads without backdriving in the absence of vibrations. All other ratios may require a brake to prevent backdriving.
- All units are suitable for intermittent operation providing that the housing temperature including ambient is not lower than -20°F or higher than +200°F. Factory supplied grease in standard units will operate in this range. For higher or lower operating temperature ranges consult Nook Industries, Inc.
- Accessories such as boots, limit switches, top plates and clevises are available.
- Catalog dimensions are representative only and are subject to change without notice. For construction, use only certified prints.
- Units are not to be used as personnel support or movement.
- End-of-travel stops are not provided.
- Tare drag torque need only be added if operating under 25% rated load.
- Starting Torque is 100% greater than torque shown.
- Measurements listed are for non-keyed jacks. See individual jack pages for keyed jack info.
|Horsepower per jack =||Torque to raise 1 pound × Number of pounds to be raised × rpm|