I have some old quilt frames with the cog wheels. It looks very much like the one you picture. There is only one set of legs on the ends. All three layers of quilt (top, bat and lining) are basted together and attached to the cloth along each pole then rolled up so most of it is on one pole. My mother used old ladies cloth belts to keep the sides taunt for hand quilting. I think the extra sets of legs must be in case they needed them for another set of poles. Sometimes there were holes drilled at intervals around the ends of the poles that fit into holes in the leg sets to prevent the poles from turning. The quilting frame takes quite a bit of room in the living space until the quilt is
finished. Hope this description helps a little.