(under subclass 21.1) Subject matter wherein the leaves of the book have a registering aperture formed in their corresponding margins or have correspondingly spaces apertures formed along their corresponding margins; and wherein the leaves are permanently secured together (a) by one or more rings or loops passed through the registering apertures of the leaves, (b) by a continuous length of wirelike material that is helically or spirally wound into a coil and passed through the registering apertures of the leaves, (c) by a continuous length of wirelike material that is bent or formed into an alternating series of oppositely disposed fingerlike loops which are then arched or curved toward one another to form a series of substantially closed rings or loops passed through the registering apertures of the leaves, or (d) by a comblike structure in which the fingers are arched or curved toward the back of the comb forming closed or substantially closed loops or rings passed through the registering apertures of the leaves.
(1) Note. A closed or substantially closed ring, coil, or loop may have a configuration other than circular as, for
example, a D-shaped configuration.
(2) Note. It is to be understood that in the definitions of this and the indented subclass, the term "leaves" may also include the covers of books which are bound simultaneously together with the leaves by the same binding means. Accordingly, these covers would usually have an aperture or apertures corresponding to the apertures in the leaves.
