Patent ID: 7946658

Claim:
In combination, a hub, a wheel, and a drive mechanism of a self propelled irrigation system, the drive mechanism being configured to drive rotation of an output member thereof around a drive axis and the hub comprising a hub body having oppositely facing first and second sides, the first side of the hub body being fixed to the output member of the drive mechanism for driven rotation of the hub body thereby about the drive axis and the second side of the hub body having the wheel supported thereon in an orientation where a central wheel axis of the wheel is at an oblique angle relative to the drive axis, whereby the hub and the drive mechanism are arranged to shift a point of engagement between the ground and the wheel back and forth axially along the drive axis under driven rotation of the hub due to the oblique angle between the drive axis and the central wheel axis, wherein the first side of the hub body has first clamping portions defining first seating surfaces seating against the output member of the drive mechanism and the second side of the hub body has second clamping portions defining second seating surfaces seating against the wheel, the first clamping portion portions lying in a first plane and the second clamping portions lying in a second plane obliquely angled relative to the first plane.