Gearing arrangement

A cylindrical double gear having an axis and a hollow unitary gear arrangement extending about the axis, wherein the gear arrangement has two hollow axially spaced gear portions with each gear portion comprising a plurality of gear teeth extending about a radial outer surface of the gear arrangement, wherein the gear portions are integrally connected together by a hollow flexible spacer portion having an outer circumference with an array of circumferentially spaced links separated by respective apertures.

A cylindrical double gear having a hollow unitary gear arrangement extending about an axis, wherein the gear arrangement has two axially spaced gear portions with each gear portion comprising a plurality of gear teeth extending about a radial outer surface of the gear arrangement, wherein the gear portions are connected by a flexible spacer portion, wherein the gear arrangement is hollow and has an inner surface defining a gear bore and an outer surface;

• wherein the minimum inner radius of the gear arrangement is the largest radius at which a circle drawn about the axis fits within the bore without intersecting the inner surface;
• wherein the maximum outer radius of the gear arrangement is the smallest radius at which a circle drawn about the axis intersects the outer surface;
• wherein the radial distance between the minimum inner radius and the maximum outer radius is less than ⅓rd of the maximum outer radius.