Abstract: A binder mechanism comprises a pair of prong plates pivotally connected by a retainer spring to toggle between a first raised position and a second lowered position. The prong plates include a plurality of ring segments affixed to the prong plates that are capable of forming loops. A cam mechanism is used to toggle the prong plates between the raised and lowered positions causing the ring segments to open or to close to form loops. The cam mechanism is preferably a slider located above the prong plates, the slider having ramps inserted through recesses between the prong plates. Preferably, the recesses are located adjacent to where the ring segments are attached to the prong plates. Cleats may hold the parts of the binder mechanism together and keep the mechanism attached to a binder assembly. Preferably, the retainer spring is in the form of a top spring covering both the slider and prong plates.