Ball Screw Jacks - Notes

  1. The recommended maximum speed is 3,000 rpm provided that the recommended horsepower and temperature are not exceeded.
  2. Input torque is shown as torque to lift one pound of load. Starting torque is 50% greater than torque shown. For loads less than 25% of rated loads add tare drag torque.
  3. Maximum (allowable) horsepower ratings are based on a 35% 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.
  4. Overload capacity of the Ball Screw Jack is as follows: 10% for dynamic loads, 30% for static loads.
  5. All Ball Screw Jacks can backdrive and require some means of holding the load, such as a brake on the motor. The product specification pages of our Worm Gear Screw Jacks Catalog show holding torque values. Holding torque represents the amount of input torque required to restrain the load and does not indicate recommended brake size to bring the dynamic load to a stop.
  6. 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.
  7. Accessories such as boots, limit switches, top plates and clevises are available.
  8. Catalog dimensions are representative only and are subject to change without notice. For construction, use only certified prints.
  9. Units are not to be used for the purpose of personnel support or movement.
  10. End-of-travel stops are not provided.
  11. Tare drag torque need only be added if operating under 25% rated load.
  12. Horsepower per jack = Torque to raise 1 pound × Number of pounds to be raised × rpm
  13. Starting Torque is 50% greater than torque shown.
  14. Measurements listed are for non-keyed jacks. See individual jack pages for keyed jack info.
Figure 1