Cover or map for binding loose leaf pages - has integral front and rear cover sheets and central spine section covered with layer of adhesive 20-50 microns thick, opt. in 3 parts

摘要

The cover or map, for binding page leaves in, comprises a front sheet (3) and a rear sheet (4), a spine and on the inside of the spine an adhesive layer. The front, rear and spine parts are a single piece and the glue spine has a total width greater than that of the cover or map. The glue spine is formed by a strip of constant thickness and is comprised of three parts. The middle part can be relatively thick across the width of the cover or map, with thinner adjacent parts sepd. by gaps. The cover is mfd. from polyester film, 20-50 microns thick.