Spring-powered drive apparatus and self-propelled caster

A spring-powered drive apparatus characterized by comprising:

• a one way clutch into which an output shaft is inserted;
• a cylindrical bush externally fitted on said one way clutch;
• a spiral spring having a radially inner end fixed to said bush and wound by turning of said output shaft in a direction in which said one way clutch transmits torque;
• and
• a casing housing said one way clutch, said bush, and said spiral spring and having a positioner that surrounds an axial end of said bush from radially outside.

The spring-powered drive apparatus characterized by comprising:

• a casing;
• a rotary shaft partly housed in said casing and mounted on said casing in a relatively rotatable manner, a one way clutch externally fitted on said rotary shaft in said casing;
• a spiral spring housed in said casing, having a radially inner end fixed to an outer ring of said one way clutch, and wound by turning of said rotary shaft in a direction in which said one way clutch transmits torque;
• a support part fixed to said casing;
• an output shaft for driving a driven member, mounted on said support part in an orientation substantially parallel to said rotary shaft in a relatively rotatable manner;
• and
• a torque transmission mechanism that transmits torque of said rotary shaft to said output shaft.

A self-propelled caster characterized by comprising:

• a casing having a cylindrical outer circumferential surface;
• a tire fixedly attached to the radially outer portion of said casing:
• a center axle partly housed in said casing, mounted on said casing in a relatively rotatable manner, and partly extending outside said casing;
• a one way clutch externally fitted on said center axle in said casing;
• a spiral spring housed in said casing, having a radially inner end fixed to an outer ring of said one way clutch, and wound when turning relative to said center axle in the direction in which said one way clutch transmits torque.