| http://www.w3.org/ns/prov#value | - In a preferred embodiment, wherein the traction wheels 18 are formed from a metal material, such as aluminum or the like, and the control ball 12 is formed from a high density plastic or the like of low compressibility, the traction wheels 18 were positioned to contact a two-inch diameter control ball at points approximately 0.10 inch below the horizontal ball equator and the rolling bearing 46 wa
|
