Wheelchair with a rehabilitation function and transmission device thereof

A wheelchair with a rehabilitation function comprising:

• a chair including a frame, two rear wheels, and two footrests, with the two rear wheels located on a rear end of the frame and respectively located on two sides of the frame in a horizontal direction, and with the two footrests located on a front end of the frame and respectively located on two sides of the frame in the horizontal direction;
• and
• two transmission devices connected to the frame and associated with the two rear wheels and the two footrests, with each of the two transmission devices including a housing, a driving shaft, a first transmission shaft, a second transmission shaft, a driven shaft, and a sliding member,
• with the driving shaft mounted in the housing and rotatable relative to the housing about a first axis, with the driving shaft including an end connected to one of the two rear wheels to permit synchronous rotation,
• with the first transmission shaft mounted in the housing and driven by the driving shaft to rotate relative to the housing about a second axis intersecting with the first axis, with an end of the first transmission shaft opposite to the driving shaft including a first reference face, with the first transmission shaft including a first engaging portion on the first reference face, with the first engaging portion having non-circular cross sections perpendicular to the second axis,
• with the second transmission shaft mounted in the housing and rotatable relative to the housing about the second axis, with the second transmission shaft mounted to the end of the first transmission shaft opposite to the driving shaft, with an end of the second transmission shaft adjacent to the first transmission shaft having a driving section,
• with the driven shaft mounted in the housing and driven by the second transmission shaft to rotate relative to the housing about a third axis parallel to the first axis and intersecting with the second axis, with the driven shaft having an end connected to one of the footrests to permit synchronous rotation,
• with the sliding member mounted around an outer periphery of the driving section to permit synchronous rotation, with an end of the sliding member adjacent to the first transmission shaft including a second engaging portion having non-circular cross sections perpendicular to the second axis, with the second engaging portion removably engaged with the first engaging portion, with the sliding member slideable along the second axis relative to the second transmission shaft between a transmission position and a release position,
• wherein when the sliding member is in the transmission position, the second engaging portion engages with the first engaging portion, and the first transmission shaft and the sliding member rotate synchronously, and
• wherein when the sliding member is in the release position, the second engaging portion disengages from the first engaging portion, and the sliding member is not driven when the first transmission shaft rotates.