Binder unit for stapled booklets

Claim 1

A binding unit for a stack of paper having opposite first and second major surfaces and a spine edge surface around which said binding unit is attached, said binding unit comprising in combination: a thin elongated generally rectangular flexible backing having an elongate edge, said backing having a first elongate portion adjacent said elongate edge contacting the first major surface of said stack of paper with the elongate edge of said backing positioned along the spine edge surface of the stack of paper; a plurality of U-shaped staples through the stack of paper and the first portion of said backing, said staples having central portions along the second major surface of the stack of paper and having terminal ends clinched over the first portion of said backing; an elongate strip of foam plastic corresponding in shape with the first portion of said backing and being adhered to the first portion of said backing on its surface opposite the stack of paper, said staples extending through said strip of foam plastic and said clinched over ends being embedded in said foam plastic, said strip of foam plastic having a thickness adapted to totally receive the clinched ends of the staples so that said ends do not extend above the foam plastic; a second strip congruent to said first strip and lying over said strip of foam plastic and over the terminal ends of said staples on the side of said strip of foam plastic opposite said stack of paper; said backing member extending from said strip of foam plastic around said second strip and being adhered to the surface of the second strip opposite said strip of foam plastic, and extending from said second strip around the spine edge surface of said stack of paper and over at least a portion of the second major surface of said stack of paper and being adhered thereto to cover the central portion of said staples.