Bicycle with selectably engageable single or dual wheel drive

A bicycle having a drive mechanism selectably engageable to drive either one or both wheels thereof comprising:

• a frame having a normally non-driven wheel and a drive wheel rotatably mounted thereon, a driven element mounted for rotation in response to driving rotation of said drive wheel, and a prime mover means connected to rotate said drive wheel;
• a power take off means connectable for positive transmission of drive power from said driven element to said normally non-driven wheel, said power take off means including a first power transmission means mounted on said frame for selective movement into either a drive position in positive interlocked power transmitting engagement with said driven element or to a disengaged position remote from said driven element, a second power transmission means mounted on said frame in positive drive power transmitting engagement with said normally non-driven wheel, a power transfer means including a rotary flexible drive shaft having power input and output ends thereon, said power transfer means mounted on said frame to receive power from said first power transmission means and transmit power to said second power transmission means;
• said power take off means having a coupling means including a support means pivotally mounted on said frame for movement toward and away from said driven element, spaced drive and idler sprockets rotatably mounted on said support means with said drive sprocket connected to drive said power transfer means, and a first endless chain trained about said drive and idler sprockets, said coupling means selectably actuable to move said first power transmission means either to said interlocated drive position causing said power take off means to connect said driven element in positive drive power transmitting relation with said normally non-driven wheel or to said disengaged position wherein driving power is not transmitted to said normally non-driven wheel;
• and
• an actuator means for selectively pivoting said support means either to said drive position wherein said first endless chain is placed in interlocked driven engagement with said driven element or to said disengaged position wherein said first endless chain is removed from driven engagement with said driven element.

In combination with a bicycle including at least one originally non-driven wheel, the improvement comprising

• a power transmission mechanism for imparting driving power to said at least one originally non-driven wheel comprising:
• a free wheel mechanism associated with said at least one originally non-driven wheel having an axle means and a driven sprocket rotatably mounted thereon;
• a support bracket means mounted on said axle means adjacent said driven sprocket;
• a driven gear means and a driving sprocket mounted for rotation on said support bracket means with said driving sprocket in spaced relation to said driven sprocket;
• an endless power transmitting chain trained about said driving and driven sprockets;
• and
• a driving gear means rotatably mounted on said support bracket means in driving relation with said driven gear means.

A replacement hub mechanism for converting an originally non-driven wheel of a bicycle to a driven wheel, comprising:

• a free wheel mechanism having an axle and a driven sprocket;
• a driven gear and a driving sprocket mounted for rotation on said support bracket with said driving sprocket in spaced relation to said driven sprocket;
• an endless power transmitting chain trained about said driving and driven sprockets;
• and
• a driving gear rotatably mounted on said support bracket in driving relation with said driven gear.