A module comprising at least the groupings (11) and (12) which remains the same for all embodiments. Assemblies (11) and (12) are effectively side by side unequal co-axial assemblies. Assembly (11) is the unequal coaxial assembly and comprises of a cam {sun-element} (17), bearing (18) and rollers {planet-element} (20). Assembly (12) is the second unequal coaxial assembly and comprises of a rotor (15), cam {sun-element} (16) and rollers {planet-element} (19) being constrained with the planet elements of the assemblies and body (45) within the body element (21) of assembly (11).
