Abstract: A variable speed drive for a continuously variable transmission includes a first transmission element that is rotatable about a first rotational axis and has a convexly-curved transmission surface that is rotationally symmetrical about a first rotational axis. A second transmission element is rotatable about a second rotational axis and has a concavely-curved transmission surface that is rotationally symmetrical about a second rotational axis parallel to the first rotational axis. The curved transmission surfaces face each other and a rigid transmission ring is positioned between and in contact with the curved transmission surfaces to transmit torque therebetween. The position of the ring on the curved surfaces is adjustable to vary the transmission ratio. The transmission surfaces are parallel to each other at least within the adjustment range of the transmission ring.

Abstract: A chain made from a number of links that are connected to each other by a hinge joint including at least one rocker member that includes a rolling surface that rolls against a rolling surface on a corresponding chain link. The rocker member is in contact with the corresponding link at least two further points, and the surface contours of the corresponding link and the rocker member are corresponding contoured curves in a region adjacent to the contact points. The load-bearing capacity in the form of the transmittable tensile force is further increased when one of the rolling surfaces is convex and one of the rolling surfaces is concave.

Abstract: A variable speed drive for a continuously variable transmission includes a first transmission element that is rotatable about a first rotational axis and has a convexly-curved transmission surface that is rotationally symmetrical about a first rotational axis. A second transmission element is rotatable about a second rotational axis and has a concavely-curved transmission surface that is rotationally symmetrical about a second rotational axis parallel to the first rotational axis. The curved transmission surfaces face each other and a rigid transmission ring is positioned between and in contact with the curved transmission surfaces to transmit torque therebetween. The position of the ring on the curved surfaces is adjustable to vary the transmission ratio. The transmission surfaces are parallel to each other at least within the adjustment range of the transmission ring.

Abstract: A friction ring variable speed drive with a continuously variable transmission ratio. A concavely curved first transmission element is rotatable around a first axis of rotation and a convexly curved second transmission element is rotatable around a second axis of rotation. The first and second transmission elements receive between them a segment of the circumference of a transmission ring. An adjusting device presses the transmission surfaces against the circumferential surfaces of the transmission ring for frictional transmission of torque between the transmission elements. The position of the transmission ring relative to the axes of rotation is variable by means of the adjusting device. A contact pressure device is provided for imposing a contact pressure between the transmission surfaces and the transmission ring, and the contact pressure increases as the transmitted torque increases.