Variable length crank arm assembly

A variable length crank arm assembly for a bicycle having a frame and a rotatable spindle, the crank arm assembly comprising,

• a crank arm coupled to the spindle for rotation about a rotational axis of the spindle, the crank arm having a proximal end adjacent the spindle and a distal end distal the spindle;
• a slide mounted upon said crank arm for slideable movement thereon between a-proximal location proximal the proximal end and a distal location adjacent the distal end;
• a pedal rotatably mounted to said slide;
• a first spring positioned to bias said slide along said crank arm longitudinal axis toward said distal end;
• and
• a second spring positioned to bias said slide along said crank arm longitudinal axis toward said proximal end,
• whereby an operator may force the slide along the crank arm against the biasing force of the second spring to elongate a stroke of the variable length crank arm and then allow the biasing force of the second spring to return the slide toward the proximal stop, and whereby the operator may force the slide along the crank arm against the biasing force of the first spring to shorten the stroke of the variable length crank arm and then allow the biasing force of the first spring to return the slide toward the distal stop.

A variable length crank arm assembly for a bicycle having a frame and a rotatable spindle, the crank arm assembly comprising,

• a crank arm coupled to the spindle for rotation about a rotational axis of the spindle, the crank arm having a proximal end adjacent the spindle and a distal end distal the spindle;
• a slide mounted upon said crank arm for slideable movement thereon between a proximal location proximal the proximal end and a distal location adjacent the distal end;
• a pedal rotatably mounted to said slide;
• a first biasing means positioned to bias said slide along said crank arm longitudinal axis toward said distal end;
• and
• a second biasing means positioned to bias said slide along said crank arm longitudinal axis toward said proximal end,
• whereby an operator may force the slide along the crank arm against the biasing force of the second biasing means to elongate a stroke of the variable length crank arm and then allow the biasing force of the second biasing means to return the slide toward the proximal stop, and whereby the operator may force the slide along the crank arm against the biasing force of the first biasing means to shorten the stroke of the variable length crank arm and then allow the biasing force of the first biasing means to return the slide toward the distal stop.