Anti-friction nut/screw drive
AssigneeIllinois Tool Works Inc.
InventorOliver Saari
Life of this patent
Estimating the term…
Abstract
An improved nut-and-screw type device for converting rotary input to linear output. The device includes an involute-helicoidal screw, a nut assembly including a plurality of annular ring and groove rollers conjugate to said screw; a freely rotating ring having internal grooves conjugate to said roller; and bearing means engaging said rotating ring and the outer housing of said nut assembly thereby providing rolling line contact for transmission of the major forces.
Claims19
An improved anti-friction screw-nut device including a nut assembly, a threaded screw having a plurality of leads extending through said nut assembly, said nut assembly including housing means, a plurality of elongate rollers equal in number to the number of leads on said screw, each of said rollers having a plurality of annular grooves forming a plurality of annular ring-like teeth conjugate to the threads of said screw, means cooperatingly locating said rollers in circumferentially spaced relation to said nut assembly and said screw, a freely rotatable ring having annular grooves for engaging and retaining said rollers in radial engagement with said screw, said ring being positioned intermediate the length of said rollers and having a width selected to provide sufficient contact between it and said rollers at a position intermediate the length of said rollers to distribute thrust over a selected area, and bearing means for transmitting thrust from said ring to said nut assembly.
An anti-friction force transmission device for conversion of rotary motion to linear motion including a multiple lead screw, a nut assembly having a plurality of no-lead elongate rollers with annular grooves, said rollers being equal in number to the number of leads on said screw and each being conjugate to the screw, a freely rotatable ring having internal grooves with no lead encircling and retaining said rollers relative to said screw, said ring having a predetermined substantial width with the center of said width being positioned intermediate the ends of said rollers, said width selected to provide sufficient contact between said ring and said rollers at a position intermediate the ends of said rollers to thereby distribute thrust over a substantial area, and housing means for completing said nut assembly and means accepting the thrust exerted by said ring and transmitting said thrust into said housing means.
Dependencies are inferred from the claim text.