Variable speed drive

摘要

A variable speed drive comprising two drives, an output drive wheel and an endless, extendible member that is driven by the drives and extends around and rotates the output drive wheel. The drives are operable to move the endless member around an endless path at a first speed at a first driving position and at a second speed at a second position. This causes local expansion or contraction of the endless member around the output drive wheel and so varies its speed.