Passive device for exercising legs of a user thereof

An exercise device comprising:

• a base;
• two support frames mounted side by side on said base and comprised of, at a bottom end, a fastening hole;
• a motor mount located between said two support frames such that said motor mount is fastened to said fastening hole of said support frames, said motor mount comprised of a horizontal through hole and a fastening plate which is provided with a vertical through hole in communication with said horizontal through hole;
• a motor comprising a spindle, said spindle comprised of, at a free end, a deceleration gear fastened thereto, said motor being mounted on said fastening plate of said motor mount such that said spindle of said motor is received in said vertical through hole;
• a transmission gear mounted on a drive axle and located in said horizontal through hole of said motor mount such that said transmission gear is engaged with said deceleration gear of said spindle of said motor, and that said transmission gear is actuated to turn via said deceleration gear by said motor in operation;
• two sprocket wheels mounted at two longitudinal ends of said drive axle in conjunction with a bearing such that said two sprocket wheels are driven to turn by said drive axle at such time when said motor is started, said two sprocket wheels being located respectively in said support frames;
• two driven chains driven respectively by said sprocket wheels;
• and
• two footrests comprised of a connection rod by which said footrests are respectively fastened to said driven chains, thereby enabling said footrests to move up and down to bring about a training effect on the legs of a person standing on said footrests at such time when said motor is in operation.