Motion transforming differentially biased transmission for human powered vehicles

A transmission for a human-powered vehicle, the transmission comprising:

• a primary system including a transmission case, a crankshaft with cog constrained to rotate about its axis within said transmission case and rigidly coupled to a pair of receiver cranks having distal ends offset by approximately 180 degrees, a pair of oscillating driver cranks each pivotally constrained to oscillate in a reciprocating manner about a respective proximal axis within said transmission case a distance from said crankshaft with cog, wherein each said driver crank is configured to receive a reciprocating input force at its distal end, a pair of connecting rods, each configured to transmit the reciprocating input force from a respective one of said driver cranks to a respective one of said receiver cranks, thereby converting the reciprocating input force into unidirectional rotary motion at the crankshaft;
• and
• a secondary biasing system operably engaged with said crankshaft with cog to provide a torque around the top and bottom dead centers of the primary system.