Low noise lead screw positioner
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorGerald S. Perkins
Life of this patent
Estimating the term…
Abstract
A lead screw positioner (10) is described, which has extremely low noise, including a nut (12) lying about a lead screw (14) and means for flowing gas under pressure between the nut and screw to keep them slightly spaced. The nut forms a plenum chamber (34) which receives pressured air, and has several holes (32) leading from the chamber to the clearance space (20) between the nut and screw to apply pressured air thereto. The nut and screw are devoid of direct sealing contact, so the pressured gas flows from the holes and axially along the screw to the end of the nut, where the gas flows into the environment.
Claims5
A low noise positioning apparatus comprising:
- a lead screw having an axis extending in an axial direction;
- a nut lying about said screw;
- said screw and said nut having electrically conductive surfaces;
- means for flowing gas under pressure between said nut and said screw and in an axial direction and out of an end of said nut into the environment, and
- means for measuring the electrical resistance between said screw and said nut, whereby to enable checking for possible contact of the nut and screw.
A low noise positioning apparatus, comprising:
- a lead screw having an axis extending in an axial direction;
- a nut lying about said screw;
- a clearance space between said screw and said nut;
- said nut having at least 3 holes therein with the holes being circumferentially spaced about the screw to carry pressurized gas to the clearance space between the nut and screw;
- said holes each passing through a crest of a thread on said nut so as to discharge gas into the root of the thread on said screw which is complementary to said crest and;
- said holes being displaced slightly from each other in an axial direction with the spacing determined by the pitch of the thread on the nut such that each of the holes passes through the crest of the nut thread,
- whereby the nut is precisely supported in an orginal position in spaced relation with respect to the screw when a pressurized gas is passed through the holes in the nut into the clearance space between the nut and the screw with lateral displacement of the nut relative to the screw causing a pressure increase in the region where the spacing between the nut and screw is decreased with the pressure increase providing a restoring force to return the nut to its original position with respect to the screw.
Dependencies are inferred from the claim text.