Patent ID: 7891631

Claim:
A supporting structure, comprises: a retractable connecting unit, a slide engaging sheet is provided on top of a fixed engaging sheet, and an adjusting member is provided between the fixed and the slide engaging sheets, a bottom end and a top end are respectively provided at the bottom portion and the top portion of the retractable connecting unit; a bottom pivotal shaft device pivotally connected to the bottom end of the retractable connecting unit via a rotation shaft, and the retractable connecting unit is rotatably and pivotally connected between a plurality of bottom supporting racks of the bottom pivotal shaft device; a top pivotal shaft device pivotally connected to the top end of the retractable connecting unit via a rotation shaft, and the retractable connecting unit is rotatably and pivotally connected to two top supporting racks of the top pivotal shaft device; at least one linking device, a bottom shaft wheel and a top shaft wheel are respectively provided between the bottom end and the top end of the lateral side of the retractable connecting unit and between the bottom supporting racks and the top supporting racks, and respectively and pivotally connected to the bottom pivotal shaft device and the top pivotal shaft device, and a flexible band is provided between the bottom and the top shaft wheels; by adjusting the adjusting member, the slide engaging sheet can move alongside the fixed engaging sheet, so the lengths of the retractable connecting unit and the top and the bottom shaft wheels disposed at the lateral side of the retractable connecting unit are changed, and a proper tension is maintained by the flexible band.