Patent ID: 6866609

Claim:
An infinitely variable ratio traction drive comprising: a torque input disc and a torque output disc, the discs having semi-toroidal surfaces disposed in juxtaposed relationship on a common rotary disc axis, one with respect to the other, to define a semi-toroidal cavity; at least one torque-transmitting roller located in the semi-toroidal cavity; the roller contacting each disc surface at a torque-transmitting contact patch; a trunnion rotatably supporting the roller for rotation about a roller axis; a gimbal frame rotatably supported for adjustment about a gimbal frame axis parallel to the common rotary disc axis; the trunnion being supported on the gimbal frame for rotary adjustment about a trunnion axis transversely disposed relative to the common disc axis; the trunnion axis being displaced angularly through a caster angle about the roller axis, the trunnion axis displacement being in a plane that is parallel to the common disc axis; a fixed gimbal support for supporting each disc and the gimbal frame; and means for rotatably adjusting the trunnion angularly about the gimbal frame axis whereby the roller supported on the trunnion rotates in an angularly offset plane, thereby creating a roller steering moment that acts on the roller to tilt the roller to a new ratio position.