Patent ID: 8011429

Claim:
A transport assembly configured to be attached to a downhole apparatus, wherein the transport assembly reduces friction between the downhole apparatus and a wellbore, the transport assembly comprising: a support assembly configured to be attached to the downhole apparatus and comprising a main longitudinal axis; a ground engaging assembly configured to contact with and move in relation to a surface of a wellbore, the ground engaging assembly engaging with the support assembly to provide for relative rotation between the ground engaging assembly and the support assembly, at least one retaining member disposed between the ground engaging assembly and the support assembly, and being operable to resist separation of the ground engaging assembly from the support assembly, the transport assembly being further configured such that, when the transport assembly is in use moving along the wellbore, the ground engaging assembly bears against the at least one retaining member and the at least one retaining member bears against the support assembly; wherein the retaining member is substantially spherical and arranged to both retain the ground engaging assembly on the support assembly and reduce friction between the ground engaging assembly and the support assembly; wherein the ground engaging assembly is configured to rotate around a radial axis which is perpendicular to the main longitudinal axis of the support assembly to reduce friction between the downhole apparatus and the surface of the wellbore resulting from movement of the downhole apparatus through the wellbore along the longitudinal axis of the wellbore.