Abstract: An erectable-collapsible enclosure structure having a top frame over which a flexible tent is draped leading to a bottom support to which the tent is attached. Two sets of upper and lower legs are pivotally connected at one end to the top frame and bottom support respectively and are pivotally connected to one another at their extending ends in a bent knee joint. The knee joints of each set lie on the opposite side of the knee joint of the other set so that the legs by-bass one another adjacent the knee joints. The top frame is manually raisable and lowerable relative to the bottom support to erect and collapse the structure. A pin placed between the upper and/or lower legs at their point of cross-over rigidly locks the structure in its erected position. Springs may be connected to the legs to assist in raising the enclosure and for holding it in its erected position. Hand levers connected to the bottom legs provide added means to operate the apparatus.