Anti-backlash nut having a free floating insert for applying an axial force to a lead screw

An anti-backlash nut designed to move along a threaded screw in either of two longitudinal directions, comprising:

• (a) a nut body adapted to receive a length of the screw, the nut body including a radial aperture extending perpendicular to the longitudinal directions;
• (b) an insert slideably received in the aperture;
• and
• (c) a resistance member for applying a force on the insert to engage the insert with a plurality of threads of the screw.

An anti-backlash nut for movement along a threaded screw in either of two longitudinal directions, comprising:

• (a) a nut body having an axial bore therethrough to receive a length of the screw, wherein a length of the bore is threaded to cooperatively engage the screw, the nut body including at least one radial aperture;
• (b) an insert having a threaded inner surface slideably received in the radial aperture such that the threaded inner surface is exposed to the axial bore;
• and
• (c) a biasing member for applying a force on the insert to operably engage the threaded inner surface with a portion of the screw to form a clearance between the threaded screw and one of the threaded bore and the threaded inner surface, the clearance formed by one of rotationally offsetting a start point of the threaded bore and the threaded inner surface, and an asymmetrical cross section in one of the threaded screw, the threaded bore and the threaded inner surface.

An anti-backlash nut for movement along a threaded screw in either of two longitudinal directions, the threaded screw having a thread profile substantially defined by first and second non parallel helical faces, the nut comprising:

• (a) a nut body having an axial bore therethrough to receive a length of the screw, wherein a length of the bore includes primary threads sized to cooperatively engage the first helical face of the threaded screw, the nut body including a radial aperture;
• (b) an insert received within the aperture, the insert having an inner surface which includes secondary threads for cooperatively engaging the second helical face of the threaded screw;
• and
• (c) a bias member for urging the insert inward to contact the primary threads with the first helical face and to contact the secondary threads with the second helical face to form a clearance between one of the first and second helical faces and one of the primary and secondary threads, the clearance formed by one of rotationally offsetting a start point of the primary threads and the secondary threads, and an asymmetrical cross section in one of the threaded screw, the primary threads and the secondary threads.

A method for translating an anti-backlash nut along a threaded screw in either of two longitudinal directions, the threaded screw having a thread profile substantially defined by first and second non parallel helical faces, the method comprising:

• (a) operably engaging primary threads of a nut body with the first helical face of the threaded screw threads;
• (b) disposing an insert in a radial aperture in the nut body for radial movement relative to the nut body;
• and
• (c) operably engaging secondary threads of the insert with the second helical face of the threaded screw threads to form clearance between the threaded screw and a portion of one of the primary threads and the secondary threads by one of rotationally offsetting a start point of the primary threads and the secondary threads, and forming one of the thread profile, the primary threads and the secondary threads to have an asymmetrical cross section.

A method of manufacturing an anti-backlash nut for cooperatively engaging a threaded lead screw, comprising:

• (a) forming a nut body having a central bore with a threaded portion for cooperatively engaging a length of the lead screw and a radial aperture intersecting the central bore;
• (b) disposing an insert in the radial aperture such that a threaded portion of the insert cooperatively engages a portion of the lead screw;
• and
• (c) creating a clearance between the lead screw and one of the nut body and the insert by one of rotationally offsetting a start point of the threaded bore and the threaded portion, and forming one of the lead screw, the threaded bore and the threaded portion to have a cross section to create the clearance.