Notebook system

A notebook system comprising:

• a plurality of sheets arranged in a stack, each sheet having a plurality of openings therein which are spaced apart along an edge of the sheets, the respective openings of each sheet in the stack being aligned with each other, each opening having a generally mushroom-shape configuration with a bulbous opening portion and a stem opening portion which connects said bulbous opening portion to an open edge of said sheet, said bulbous opening portion defined by an arcuate surface having opposite ends and a substantially flat bearing surface having opposite ends which are substantially coincident with the opposite ends of said arcuate surface, and said small opening portion being defined by a narrow channel opening having a width smaller than a with of said flat bearing surface and connecting the open edge of said sheet to said flat bearing surface;
• a plurality of disk-like fastening members insertable in respective openings of said stack of sheets to retain said sheets in said stack;
• said disk members each having a substantially flat disk-like central surface portion having a central axis, and an enlarged continuous rim portion which extends around the periphery of the central surface portion of said central surface portion, said rim portion projecting outwardly in a direction substantially perpendicular to the central axis of said substantially flat central surface portion;
• said central surface portion of each disk member having a radius (R1) which is larger than a thickness of said stack of sheets to be bound thereby, and said central surface portion extending within said stem opening portion;
• and
• said projecting rim portion of each of said disks including an arcuate outer peripheral surface having opposite ends and a substantially flat inner facing bearing surface having opposite ends which are substantially coincident with the opposite ends of said arcuate outer peripheral surface, with said projecting rim portion extending within said bulbous opening portion such that said substantially flat inner facing bearing surface bears upon said substantially flat bearing surface of said bulbous opening portion of said openings of said sheets of said stack which are bound by said disks members.