Patent ID: 7887423

Claim:
A universal joint comprising: an outer member defining an interior opening and a plurality of grooves disposed within said interior opening and extending along a longitudinal axis with each of said plurality of grooves being parallel to all other of said plurality of grooves and including a straight linear profile along said longitudinal axis; an inner member disposed within said interior opening and defining a plurality of pockets disposed radially about said longitudinal axis with each of said plurality of pockets opposing one of said plurality of grooves; a plurality of drive balls each having a spherical shape and each of said plurality of drive balls rotatable within one of said plurality of pockets and disposed within one of said plurality of grooves with each of said plurality of drive balls including a ball center and a central axis extending through said ball center of each of said plurality of drive balls and intersecting said longitudinal axis at a perpendicular angle; each of said plurality of drive balls contacting one of said plurality of pockets along an annular contact interface and including a first pocket radial line extending from said ball center to said annular contact interface and a second pocket radial line coplanar with said first pocket radial line and extending from said ball center to said annular contact interface on an opposing side of said central axis to define a pocket contact angle measured between said first pocket radial line and said second pocket radial line and each of said plurality of drive balls contacting one of said plurality of grooves along a first linear interface and a second linear interface and including a first groove radial line extending between said ball center and said first linear interface and a second groove radial line extending between said ball center and said second liner interface on an opposing side of said central axis to define a groove contact angle measured between said first groove radial line and said second groove radial line with said pocket contact angle being less than said groove contact angle to urge each of said plurality of drive balls upward against said plurality of grooves as said inner member articulates relative to said outer member.