Insert for pneumatic wheel

A resilient wheel having:

• a circular hub;
• an annular tire rim of substantially U-shaped cross section secured to the exterior circumference of the hub, a cross section of the rim being symmetric about a hub diameter in the cross sectional plane;
• the rim, relative to the hub, having a first portion extending in both directions axially from the hub;
• to either side of the first portion a second portion extending in an axial and radial direction;
• a third portion extending from each second portion in an axial direction;
• a fourth portion extending radially from each third portion;
• a fifth portion extending from each fourth portion in an axial direction;
• a one-piece annular elastomeric member bonded against and conforming to the shape of both third, both fourth, and both fifth rim portions on the side of the rim away from the hub, and extending between the third portions such that a first sealed airtight space is defined by the inner surface of the elastomeric member and the surfaces of the first and both second rim portions on the side of the rim away from the hub;
• and
• a tire mounted on the rim forming a second sealed airtight space defined by the outer annular surface of the elastomeric member and tire , the elastomeric member being sufficiently resilient to allow transient pressure changes in the second sealed airtight space caused by external tire impact to be transmitted to and absorbed by the first sealed airtight space;
• and
• the elastomeric member having two continuous radially extending portions, each being located at an equal distance in an axial direction inwardly from one side of the rim, the distance being such that each bead of a tire mounted on the rim resides between a radially extending portion of one side of the rim and one of the extending portions of the elastomeric member, and is subsequently held in place.