Document file has spine with extension panels folded to retain documents between covers

摘要

The document has a flat blank (14) with a spine (16) and two cover panels (17). Two strips (20,21) extend from the spine longitudinally to define an upper and a lower channel section and four flaps (26) hinged along the edges of the strips. The blank can have a sub assembly (12) with a spine strip defining at least part of the spine.