Patent ID: 7803077

Claim:
A constant torque automatic transmission for a bicycle comprising: a crank driving a crank driving member, a drive base; a first cone member having a small diameter end and a large diameter end, said first cone member being rotatably retained to rotate about the cone axis by a first cone yoke, said first cone yoke being pivotally retained by said drive base at a first axial end of said first cone member on a pivot axis, said pivot axis being different from the cone axis, rotation of said crank drives said crank driving member drivingly engaged to a second axial end of said first cone member to pivot said first cone member about the pivot axis and to rotate the first cone member about the cone axis; a second cone member having a small diameter end and a large diameter end, said second cone member being rotatably retained by said drive base, said small diameter end of said first cone member being positioned adjacent said large diameter end of said second cone member, a rear wheel of the bicycle is driven rotated by said second cone member; a biasing member causing a first axis of said first cone member to move toward a second axis of said second cone member; and a cone drive member being sized to be received by an outer perimeter of said first cone and second cone members, said first cone member causes rotation of said second cone member through said cone drive member, a drive ratio of said first and second cone members as determined by a position of said cone drive member is instantaneously adjusted by pivoting of said first cone member about the pivot axis according to force applied to the crank; wherein the axes of said first and second cone members are parallel when a predetermined force is applied to said crank; wherein the axes of said first and second cone members are not parallel when the force applied to said crank deviates from said first predetermined force.