Patent ID: 6112838
Filing Date: 2000-09-05
Classification: B64F,Y10S

Abstract:
An apparatus for towing a workpiece comprising:a first frame having a first generally cylindrical member with an inside radial surface and an outside radial surface;a second frame in spaced vertical relationship to the first frame, said second frame having a second generally cylindrical member with an inside radial surface and an outside radial surface;a wheel assembly supported by said first frame and having a wheel axle having a first axis and wheel rotatable about said first axis to drive movement of said apparatus;a motor to power said wheel assembly;a handle assembly attached to said first frame to rotate said first frame relative to said second frame; anda gripper assembly supported by said second frame and offset from said vertical axis, said gripper assembly being positioned on said second frame and adapted to engage a workpiece for towing along a towing plane that passes above or below the first axis by a vertical distance no more than about 60% of the radius of said wheel; andwherein one of said first and second cylindrical members is concentrically disposed about said other cylindrical member, such that said cylindrical members are rotatable relative to one another so as to enable rotation of said first frame relative to said second frame about a common substantially vertical axis; andwherein an inside radial surface portion of one of said cylindrical members is frictionally engageable with an outside radial surface portion of said other cylindrical member upon generally forward or generally rearward movement of said first frame relative to said second frame, such that generally horizontal movement of said first frame is transmitted to said second frame through frictional engagement between said radial surface portions, said towing plane passing from a point of engagement between said gripper assembly and the workpiece through each of said frictionally engaging radial surface portions, and wherein said first and second cylindrical members are concentrically disposed about said wheel assembly such that said first axis intersects said radial surfaces of both said first and second cylindrical members and such that said towing plane intersects said frictionally engaging radial surface portions at a location above or below the first axis by a vertical distance of no more than about 60% of the radius of said wheel.