US Patent 8132687 Double-walled container and method of manufacture

A double-walled container and method of manufacturing are disclosed. A first container having a smaller diameter than a second container is inserted into the second container. A portion of the first container is expanded and/or a portion of the second container may be narrowed so that first and second container is interlocked and form a double-walled container. The first and/or second containers may have ribs. An air gap between the first and second containers provides thermal insulation to contents of the double-walled container.