Patent ID: 7287636

Claim:
A driving device comprising: a shaft having a central axis; a main body supported by the shaft; and at least one side body provided at the side of the main body and supported by the shaft; wherein the main body comprises a roller supported rotatably relative to the shaft and around the central axis of the shaft, and a motor, a first planetary gear mechanism and a power transmitting member all accommodated in the roller, and wherein the side body comprises a casing supported unrotatably relative to the shaft, and a second planetary gear mechanism and a rotational member both accommodated in the casing, each of the power transmitting member and the rotational member being supported rotatably relative to the shaft, the first planetary gear mechanism comprising a first sun gear, a first planet gear disposed at the outer side of the first sun gear, and a first internal gear disposed at the outer side of the first planet gear, wherein the first planet gear is arranged to engage with the first sun gear and the first internal gear, wherein the first internal gear is arranged in the roller unrotatably relative to the roller, and wherein the first sun gear is adapted to rotate relative to the shaft and around the central axis of the shaft upon reception of torque generated by the motor, the power transmitting member having a first projection extending out in a direction along the shaft for supporting the first planet gear rotatably relative to the first projection, the rotational member having a second projection extending out in a direction along the shaft, the second planetary gear mechanism comprising a second sun gear, a second planet gear disposed at the outer side of the second sun gear, and a second internal gear disposed at the outer side of the second planet gear, wherein the second sun gear is connected to the power transmitting member and arranged to rotate integrally therewith, wherein the second internal gear is arranged in the casing unrotatably relative to the casing, and wherein the second planet gear is supported rotatably relative to the rotational member and around the central axis of the second projection.