Power transmission

A power machine actuated by a rotating power force driving a gear transmission of said power machine, said gear transmission comprising:

• a housing accommodating a gear ratio changing mechanism and having a central hub;
• a gear plate articulated to an output shaft coaxially rotatable about an axis of said central hub, said gear plate comprising a plurality of coaxially disposed gear rings selectively engaged by said gear ratio changing mechanism;
• a transmission plate coaxially rotatable about an axis of said central hub of said housing and having a peripheral gear ring coupled to said gear ratio changing mechanism, said gear ratio changing mechanism comprising:
• a pinion gear rotatably articulated with an axle and engaged with the peripheral gear ring of the transmission plate for transferring input rotary motion thereby received to said axle;
• a transmission pinion gear rotatable by said axle and being displaceable along said axle for engaging one of the coaxially disposed gear rings of said gear plate;
• and a manipulator configured for selective radial displacing the transmission pinion gear over said axle between gear rings of the gear plate, and wherein one of the transmission plate and the output shaft is connectable to the rotating power source and the other one of the transmission plate and the output shaft is connectable to a rotating driven power unit.

A bicycle configured with a gear transmission, the gear transmission comprising:

• a housing accommodating a gear ratio changing mechanism and having a central hub;
• a gear plate articulated to an output shaft coaxially rotatable about an axis of said central hub, said gear plate comprising a plurality of coaxially disposed gear rings selectively engaged by said gear ratio changing mechanism;
• a transmission plate coaxially rotatable about an axis of said central hub of said housing and having a peripheral gear ring coupled to said gear ratio changing mechanism, said gear ratio changing mechanism comprising:
• a pinion gear rotatably articulated with an axle and engaged with the peripheral gear ring of the transmission plate for transferring input rotary motion thereby received to said axle;
• a transmission pinion gear rotatable by said axle and being displaceable along said axle for engaging one of the coaxially disposed gear rings of said gear plate;
• and a manipulator configured for selective radial displacing the transmission pinion gear over said axle between gear rings of the gear plate, and wherein the transmission plate is rotatably manipulable by a bicycle crank assembly and the output shaft is engageable with a rear hub assembly of a rear bicycle wheel.

A rear wheel for a bicycle configured with a gear transmission, the gear transmission comprising:

• a housing accommodating a gear ratio changing mechanism and having a central hub;
• a gear plate articulated to an output shaft coaxially rotatable about an axis of said central hub, said gear plate comprising a plurality of coaxially disposed gear rings selectively engaged by said gear ratio changing mechanism;
• a transmission plate coaxially rotatable about an axis of said central hub of said housing and having a peripheral gear ring coupled to said gear ratio changing mechanism, said gear ratio changing mechanism comprising:
• a pinion gear rotatably articulated with an axle and engaged with the peripheral gear ring of the transmission plate for transferring input rotary motion thereby received to said axle;
• a transmission pinion gear rotatable by said axle and being displaceable along said axle for engaging one of the coaxially disposed gear rings of said gear plate;
• and a manipulator configured for selective radial displacing the transmission pinion gear over said axle between gear rings of the gear plate, and wherein the transmission plate is configurable for rotation by a bicycle crank assembly and the output shaft is configurable for engaging with a rear hub assembly of the rear bicycle wheel.