Patent ID: 8708068
Filing Date: 2014-04-29
Classification: B60B,B62D,B62K

Abstract:
1. A friction drive device, comprising: a frame; a pair of drive disks rotatably supported by the frame opposite to each other in a substantially coaxial relationship; a power source mounted on the frame for individually rotatively actuating the drive disks; a traction wheel interposed between the drive disks, the traction wheel including a plurality of articulation members pivotally connected in tandem into a loop and a free roller rotatably supported by each articulation member so as to be rotatable around an axial line extending along the loop, the articulation members being pivotally movable around pivot axial lines extending in parallel with a center line of the drive disks; and a plurality of drive rollers pivotally supported along a peripheral part of each drive disk at a substantially regular angular interval and in a skewed relationship to the center line of the drive disks, and engaging the free rollers over an entire circumference of the traction wheel; wherein opposing end faces of each adjoining pair of the articulation members are provided with abutting surfaces that define an opening angle between each adjacent pair of free rollers, said opening angle greater than a minimum angle that causes the adjoining free rollers to engage a ground surface without becoming parallel to each other, but allows a plurality of the free rollers to engage the ground surface at the same time.