depicts an end view of the peripheral end of the forked plug including the ribs 17 and shoulders 19 the cross sectional dimensions of ribs 17 form a cylindrical shape that is substantially the same as the inner diameter of the tube of a collapsible structure when a tube is slid over the ribs its travel is stopped by crown 16 further the ribs deform slightly enabling them to accommodate small changes in the inner diameter of the tubes such as may result from manufacturing inconsistency of the tubes and allowing the shoulders and ribs to grip the inner surface of the tubes fig8 depicts a plan view of the articulating hub assembly including the keeper hub cover and forked plug as described above in the preferred embodiment the hub assembly is provided with eight forked plug as shown in fig8 the keeper is provided with a central well 21 and two peripheral wells 22 for application of torque by means of a tool for the purpose of making the assembly operable by those without sufficient manual dexterity to operate the hub assembly without tools the hub cover has openings 9 which coincide with registered openings in the hub body fig9 is a perspective view of the articulating hub assembly of the present invention depicting openings.