Patent ID: 7727272

Claim:
A one-piece expandable flat bearing structure comprising at least partially elastically deformable struts which are separated from each other by openings in the bearing structure, the struts including: spring struts having an anchor region on a first end and extending to a resiliently deflectable second end, the spring struts being elastically resilient with respect to the anchor regions, hinge struts adjoining said spring struts at the resiliently deflectable second ends of the spring struts, forming a hinge axis at the juncture of a spring strut and a hinge strut, the hinge axis extending transversely with respect to the bearing structure at the juncture of the spring strut and the hinge strut, and each hinge strut having a central axis, wherein the bearing structure can assume at least one compressed condition, at least one transitional condition, and at least one expanded condition and wherein the bearing structure has at least one expansion direction, and wherein a reference axis extends within the bearing structure in approximately parallel relationship with a longitudinal axis of the bearing structure and transversely with respect to the expansion direction and transversely with respect to the hinge axis, wherein the spring struts and the hinge struts are of such a configuration and arrangement that the bearing structure is capable of going from a compressed condition to a transitional condition, to an expanded condition, and wherein in the compressed state, the spring strut and hinge strut bear closely against each other and are separated by cuts, and the central axis of the hinge strut is transverse to the reference axis, and wherein in the transitional condition, the hinge strut is pivoted at the hinge axis in an expansion direction of the bearing structure such that the central axis of the hinge strut is approximately parallel to the reference axis and the spring struts rotate in a first direction such that the spring struts are initially resiliently deflected transversely to the expansion direction of the bearing structure, and wherein in the expanded condition, the hinge strut additionally pivots at the hinge axis in the expansion direction of the bearing structure beyond the reference axis such that the central axis of the hinge strut is transverse to the reference axis and the spring struts rotate in a second direction opposite to the first direction, thereby providing that both the compressed condition of the bearing structure and also the expanded condition of the bearing structure are stabilized by a spring action emanating from the spring struts.