Transmission with two parallel driving shafts bearing two driving gears each meshed with same driven gear on parallel driven shaft

A transmission mechanism for a vehicle, for receiving input of rotational power from a power supplying member which rotates in a particular rotational direction and for outputting rotational power to a power receiving member, comprising:

• an input member connected to said power supply member and which is rotatably mounted and receives supplying of said rotational power from said power supply member;
• a first driving gear wheel shaft;
• a second driving gear wheel shaft mounted generally parallel to said first driving gear wheel shaft;
• a driven gear wheel shaft mounted generally parallel to said first and second driving gear wheel shafts, said driven gear wheel shaft being rotationally connected to said power receiving member;
• a first driven gear wheel fixedly mounted on said driven gear wheel shaft;
• a first driving gear wheel which is rotatably mounted on said first driving gear wheel shaft and is in constant mesh with said driven gear wheel, said first driving and driven gear wheels providing a first reduction gear ratio from said first driving gear wheel shaft to said driven gear wheel shaft;
• a second driven gear wheel fixedly mounted on said driven gear wheel shaft;
• a second driving gear wheel which is rotatably mounted on said second driving gear wheel shaft and is in constant mesh with said first driven gear wheel, said second driving and said first driven gear wheels providing a second reduction gear ratio smaller than said first reduction gear ratio from said second driving gear wheel shaft to said driven gear wheel shaft;
• a third driving gear wheel which is rotatably mounted on said first driving gear wheel shaft and is in constant mesh with said second driven gear wheel, said third driving and said second driven gear wheels providing a third reduction gear ratio smaller than said second reduction gear ratio from said first driving gear wheel shaft to said driven gear wheel shaft;
• a fourth driving gear wheel which is rotatably mounted on said second driving gear wheel shaft and is in constant mesh with said second driven gear wheel, said fourth driving and said second driven gear wheel providing a fourth reduction gear ratio smaller than said third reduction gear ratio from said second driving gear wheel shaft to said driven gear shaft;
• a first synchromesh device which engages said first driving gear wheel with said first driving gear wheel shaft when said first synchromesh device is shifted to one side of a neutral position thereof and which engages said third driving gear wheel with said first driving gear wheel shaft when said first synchromesh device is shifted to the other side of said neutral position thereof opposite to said one side;
• a second synchromesh device which engages said second driving gear wheel with said second driving gear wheel shaft when said second synchromesh device is shifted to one side of a neutral position thereof and which engages said fourth driving gear wheel with said second driving gear wheel shaft when said second synchromesh device is shifted to the other side of said neutral position thereof opposite of said one side;
• a first clutching device comprising a rotational power input member and a rotational power output member, mounted proximate to one end of said first driving gear wheel shaft with its rotational power output member rotationally coupled to said first driving gear wheel shaft, which according to selective control thereof is able to selectively couple said first driving gear wheel shaft to said input member in either relative rotational direction, and couple said first driving gear wheel shaft to said input member in a first relative rotational direction only, said first relative rotational direction being a direction in which rotational power is required to be transmitted through said first clutching device in order to rotationally power said first driving gear wheel shaft from said power supplying member via said input member and said first clutching device when said power supplying member is being rotated in said particular rotational direction;
• and
• a second clutching device comprising a rotational power input member and a rotational power output member, mounted proximate to the one end of said second driving gear wheel shaft with its rotational power output member rotationally coupled to said second driving gear wheel shaft, which according to selective control thereof is able to selectively couple said second driving gear wheel shaft to said input member in either relative rotational direction, and couple said second driving gear wheel shaft to said input member in a second relative rotational direction only, said second relative rotational direction being a direction in which rotational power is required to be transmitted through said second clutching device in order to rotationally power said second driving gear wheel shaft from said power supplying member via said input member and said second clutching device when said power supplying member is being rotated in said particular rotational direction wherein one of said rotational power input members of said first and second clutching devices is coaxially rotationally coupled to said input member;
• and
• rotational power transfer means including a first power transfer gear wheel coaxially rotationally coupled to said one of said rotational power input members of said first and second clutching devices, a second power transfer gear wheel coaxially rotationally coupled to the other of said rotational power input members of said first and second clutching devices, and an intermediate power transfer gear wheel rotatably mounted on said driven gear wheel shaft and meshed with said first and second power transfer gear wheels.