Alternating Drive, Primarily for Bicycles and Similar Driven Vehicles

Alternating drive, primarily for bicycles and similar driven vehicles, wherein the vehicle comprises a frame (1) and a driven wheel (2) pivotally connected to the frame (1), said drive comprising a pair of identically designed drive units with opposite driving directions mounted to respective sides of the frame (1), said drive units each comprise respective swinging arms (10, 10′) pivoted around a common swinging shaft (11) mounted in the frame (1) to perform alternating swinging motion around the swinging shaft (11), each swinging arm (10, 10′) has a respective driving arm (16, 16′) with an edge defining a driving path (18, 18′), said units comprise a common driving shaft (4) mounted and pivoted in said frame (1) for circular motion around a driving axis, each of said driving units comprises a respective bolt (9, 9′) with an axis substantially parallel to said driving axis and connected to and rotating with said common driving shaft (4) along respective circular paths around said driving axis, and a driving wheel (15, 15′) connected to and pivoted on said bolt (9, 9′), said driving wheels (15, 15′) are biased to the associated one of said driving paths (18, 18′) so that the rotation of said driving wheels (15, 15′) rolling in a first and then in a returning second direction along said associated driving path (18, 18′) causing said swinging arm (10, 10′) to perform an alternating swinging motion, said driving wheels (15, 15′) being mechanically connected to each other and in each position they are by 180° angularly offset with respect to each other around said driving shaft (4), respective flexible ropes (28, 28′) being connected to an associated one of said swinging arms (10, 10′), and respective biased rope drums (61, 61′) mounted around the shaft of said driven wheel (2) and connected to the driven wheel (2) in a manner that allows transmission of torque to said wheel (2) from said rope drum (61, 61′) in a single but mutually different direction of rotation only, wherein said ropes (28, 28′) being connected to and wound with respective predetermined number of turns around the associated rope drum (61, 61′) so that during the driving operation the number of said turns is changing in a mutually alternating manner, characterized in that each swinging arm (10, 10′) further comprises:

• a head portion (14, 14′) surrounding said swinging shaft (11) and connected to inner end of said driving arm (16, 16′);
• a traction arm (17, 17′) connected with inner end thereof to said head portion (14, 14′);
• and a connection arm (20, 20′) interconnecting outer ends of said driving arm (16, 16′) and of said traction arm (17, 17′), wherein said driving arm (16, 16′), traction arm (17, 17′) and connection arm (20, 20′) define together an opening, and the shaft of said driving wheel (15, 15′) being positioned in said opening, said traction arm (17, 17′) defining a traction path (19, 19′) at its edge facing towards said opening that determines substantially the momentary transmission ratio, and each drive unit comprises at least one rope wheel (26, 26′) so that said rope (28, 28′) being wound around said rope wheel (26, 26′) that comprises a shaft (35, 35′) guided along said traction path (19, 19′).