Pre-loaded self-aligning roller nut assembly for standard micrometer spindle and the like

A roller nut assembly for use on a lead screw, comprising:

• a housing;
• first and second bearings each having an inner race, an outer race and a plurality of balls disposed between said inner and outer races, said first and second bearings being angularly supported within said housing;
• and
• spring means for preloading said first and second bearings;
• wherein the inner races of said first and second bearings have a flank engaging portion for engaging a flank of a helical thread of said lead screw and wherein the inner races of said first and second bearings have a crest engaging portion for engaging a crest of said helical thread of said lead screw.

A linear displacement device, comprising:

• a lead screw having a helical thread, said helical thread having a leading flank portion, a following flank portion, and a crest portion;
• and
• a roller nut assembly including:
• a housing;
• first and second bearings each having an inner race, an outer race and a plurality of balls disposed between said inner and outer races, said first and second bearings being supported by said housing;
• and
• a leaf spring disposed between said first and second bearings, said leaf spring biasing said first and second bearings in opposing directions such that said first and second bearings are preloaded;
• wherein the inner races of each of said first and second bearings have a flank engaging portion for engaging one of said flanks of said helical thread of said lead screw.