Abstract: A collapsible supporting frame structure for portable shelters which includes a plurality of radially extending pivoted legs having their upper ends pivotally connected with an upper supporting ring and intermediate portions having a pivotal link connection with a lower supporting structure and a hollow slide member with its lower end fixed to the lower supporting structure and slidably mounted through said upper ring, whereby the raising of the hollow slide member through the upper ring causes radial expansion of the supporting leg structure into outwardly spaced, ground-engaging position and including the extension of said hollow member upwardly through said ring to provide a smoke stack for the area confined under the supporting leg structure.