Low Backlash Reverse Worm Screw Jacks, Zero Backlash Reverse Machine Screw Actuators, Anti-Backla...
Low Backlash Reverse Worm Screw Jacks, Zero Backlash Reverse Machine Screw Actuators, Anti-Backlash Nut Screw Jack Features:
Screw jacks are used for positioning loads in numerous applications, however when the load direction alternates between tension and compression within the operating cycle and a high position accuracy must be maintained then a specific type of screw jack is required. The Anti Backlash Machine Screw Jacks is recommended for such applications, as it is able to reduce the axial backlash between the lead screw and the trapezoidal screw thread in the gear to a practical minimum.
Axial backlash exists in standard screw jacks as the "gap" or "play" between the flanks of the lead screw thread and the internal thread on the worm gear nut. This gap or play is due not only to normal manufacturing tolerances, but to the fact that there must be some clearances to prevent binding and galling when the screw jack is operating under load. In most applications either the load direction is constant so axial backlash does not occur or the position error caused by the axial backlash is considered negligible for the application. However some applications require minimal or regulated axial backlash for accurate and repeatable positioning. Such an application is for positioning the rollers in steel straightening machines for tube, bar or sheet steel production.
Anti-backlash mechanism on screw jacks can be used to reduce axial-backlash to a practical minimum or a regulated value. Reduction in axial backlash below this minimum is not normally recommended as it can cause binding and excessive wear. As the screw jack is operated over time the axial backlash will increase as the lead screw thread on the gear wears due to normal operation. To compensate for this anti-backlash device can be adjusted to re-set for the required amount of regulated backlash. To help with the identification of wear machine screw jacks can also be fitted with a wear monitoring device for visual use or with electronic sensing for integration into a motion control system.