Variable ratio bicycle drive mechanism

A drive mechanism (21R, 21L) for imparting rotational motion to a drive axle (15) rotatably coupled to a frame (2), said mechanism comprising:

• (a) right and left axles (33R, 33L) rotatably coupled to said frame (2), parallel to said drive axle;
• (b) right and left pedal arms (30R, 30L) connected. transversely to said right and left axles respectively;
• (c) right and left intermediate arms (37R, 37L) connected transversely to said right and left axles respectively, at an angle .phi. relative to said right and left pedal arms respectively;
• and
• (d) right and left linkage means connected between said intermediate arms and said drive axle wherein said left and right linkage means comprise right and left crank arms (41R, 41L) connected transversely to said drive axle and, right and left connecting links (39R, 39L) pivotally connected between said respective intermediate arms and crank arms and wherein said right and left crank arms cross said right and left intermediate arms respectively when said right and left connecting links are uppermost in their trajectories.

A drive mechanism (21R, 21L) for imparting rotational motion to a drive axle (15) rotatably coupled to a frame (2), said mechanism comprising:

• (a) right and left axles (33R, 33L) rotatably coupled to said frame (2), parallel to said drive axle;
• (b) right and left pedal arms (30R, 30L) connected transversely to said right and left axles respectively;
• (c) right and left intermediate arms (37R, 37L) connected transversely to said right and left axles respectively at an angle .phi. relative to said right and left pedal arms respectively;
• and
• (d) right and left linkage means connected between said intermediate arms and said drive axle
• wherein said left and right axles are journalled for rotation in left and right outriggers connected to said frame, said left and right axles are movable relative to said frame for varying the distances between said driving axle and said left and right axles and further comprising locking means for locking said left and right axles in place with respect to said frame and, wherein said left and right outriggers are two ends of an outrigger member pivotally connected to said frame near its midpoint, said left and right axles are journalled for rotation near the ends of said left and right outriggers, and said locking means locks said outrigger member with respect to said frame.

A drive mechanism (21R, 21L) for imparting rotational motion to a drive axle (15) rotatably coupled to a frame (2), said mechanism comprising:

• (a) right and left axles (33R, 33L) rotatably coupled to said frame (2), parallel to said drive axle;
• (b) right and left pedal arms (30R, 30L) connected transversely to said right and left axles respectively;
• (c) right and left intermediate arms (37R, 37L) connected transversely to said right and left axles respectively, at an angle .phi. relative to said right and left pedal arms respectively;
• and
• (d) right and left linkage means connected between said intermediate arms and said drive axle
• wherein said left and right axles are journalled for rotation in left and right outriggers connected to said frame, said left and right axles are movable relative to said frame for varying the distances between said driving axle and said left and right axles and further comprising locking means for locking said left and right axles in place with respect to said frame and, wherein said outriggers each comprise a first member connected to said frame;
• a first plate connected to said first member;
• a second plate in sliding contact with said first plate;
• bearing means rotatably mounting said left and right axles respectively to said second plate;
• fastening means for clamping said first plate to said second plate;
• and gripping surfaces on said first and second plates for preventing said first plate from sliding with respect to said second plate when said fastening means are engaged.

A drive mechanism for deriving rotational motion from human power, said drive mechanism comprising:

• (a) a frame having a forward end, a rearward end, an upper side, a lower side, a left side and a right side;
• (b) a first transverse driving axle having an axis, a left end and a right end journalled for rotation in said frame;
• (c) a left crank arm connected to and extending radially away from said left end of said first axle;
• (d) a right crank arm connected to and extending radially away from said right end of said first axle in a direction opposite to said left crank arm;
• (e) left and right axles each having a left end, a right end and an axis, and each being journalled for rotation relative to said frame and spaced apart from said first axle;
• (f) a left intermediate arm connected to and extending radially from said right end of said left axle said left intermediate arm rotatable with said left axle through a full circle about an axis of said left axle;
• (g) a right intermediate arm connected to and extending radially from said left end of said right axle said right intermediate arm rotatable with said right axle through a full circle about an axis of said right axle;
• (h) a left connecting link pivotally attached to said left crank arm at a point spaced apart from said first axle and pivotally attached to said left intermediate arm at a point spaced apart from said left axle;
• (i) a right connecting link pivotally attached to said right crank arm at a point spaced apart from said first axle and pivotally attached to said right intermediate arm at a point spaced apart from said right axle;
• (j) a left pedal arm connected to and extending radially from said left end of said left axle said left pedal arm rotatable with said left axle through a full circle about said axis of said left axle;
• and
• (k) a right pedal arm connected to and extending radially from said right end of said right axle said right pedal arm rotatable with said right axle through a full circle about said axis of said right axle.