US Patent 10478659 Dynamically variable radius cam for weight lifting apparatus

A variable radius cam mechanism is configured for use in a weight lifting apparatus. The variable radius cam mechanism includes a disk configured to rotate about an axis. The cam mechanism includes a cable guide coupled to the disk and defining a path for a cable and a radial tangent distance between the cable and the axis. The cam mechanism further includes one or more actuators coupled to the disk and the cable guide and configured to move the cable guide relative to the disk to change the radial tangent distance during rotation about the axis. The cam mechanism includes a controller programmed to operate the one or more actuators to cause the one or more actuators to move the cable guide to change the radial tangent distance thereby changing a force transferred through the cam mechanism.