Automatically driving force releasing type one way rotation driving instrument

An automatically driving force releasing type one way rotation driving instrument for a wheelchair, comprises:

• a one way clutch for transmitting a driving force only when an output shaft is connected to a drive wheel of the wheelchair to drive an input shaft in a direction in which the wheelchair moves forwardly;
• a rope member wound around at least one part of an outer periphery of said input shaft of said one way clutch;
• pulling means for pulling one end of said rope member with respect to a central part thereof, which is wound around said outer periphery of said input shaft, in a direction away from said input shaft;
• and
• restraining means for restraining the other end of said rope member with respect to said central part thereof from moving in a direction of said input shaft due to pulling with said pulling means, said input shaft being driven to rotate in one direction with a pulling force of said pulling means via said rope member due to friction resistance between said rope member wound around said input shaft of said one way clutch and said input shaft, which is generated with pulling of said pulling means and restraining of said restraining means, such that when said pulling force becomes zero, said friction resistance becomes zero to automatically release transmission of the driving force.