Ring binder assembly

#This invention relates to ring binders. As used herein, the term "ring binder assembly" means an empty folder or book having a spine, in combination with a metal ring mechanism attachable to the spine. A typical ring mechanism comprises a metal shell riveted along the spine, a pair of hinged blades retained in compression by the shell, and opposed half-rings attached to both blades in such a way that the half-rings can be snapped closed to retain punched papers in the binder.

#A ring mechanism of the sort contemplated by this invention is shown and described in U.S. Pat. No. 4,552,478, the disclosure of which is incorporated into this specification.

#Ring binders such as the well-known three-ring binder are normally permanently assembled at the factory, then boxed and shipped. A consequence is that, particularly for binders having wide spines, shipping density is low: even though the binders are alternated in direction as they are packed in cartons, most of the volume of the cartons is air. Because low shipping density results in high transportation costs, and shipping costs are a large part of the delivered cost of ring binders, it would be advantageous to achieve higher shipping densities.

#In the accompanying drawings,

#FIG. 1 is an exploded perspective view of a ring binder assembly embodying the invention;

#FIG. 2 is a perspective view, from above, of a low-profile fastener attached to the spine of the binder;

#A ring binder assembly embodying the invention is shown in FIG. 1. The assembly comprises a folder 10, having reinforced front and rear flaps 12, 16 interconnected by a spine 14. Flexure occurs along hinge lines 18 at both sides of the spine formed for example by a narrow unreinforced layers of plastic which also cover the reinforcement in the spine and the flaps.

#The ring mechanism 20 may be attached to the folder by sliding the mushroomed feet 22 of its tubular rivets 24 (FIG. 3) into the low-profile receptacles 40 shown in detail in FIG. 2, until the heads are secured beneath the center portion of the receptacles. In FIG. 3, one can see the bottoms of the blades 26,28 and the ring halves 30,32 extending upward from the shell 34. The blades have interdigitated fingers which cause them to act as a hinge, and their outer edges seat in grooves formed at the edges of the shell, which acts as a compression spring. The end lever 36, when pressed outward, pushes the blades upward, flattening the shell slightly as they pass center, and opening the rings.

#The receptacle 40 shown in FIG. 2 is stamped from sheet metal, and includes a planar center portion 42 having a specially designed "U"-shaped cutout 44 as wide as the diameter of the tubular rivets 24, and intersecting a side of the center portion. A pair of tabs 46 are formed at opposite ends of the center portion, each offset downward from the center section by at least the thickness of the tubular rivet's head, so that the mush-roomed foot 22 of the rivet can seat within the space beneath the center section as suggested by the arrow. Each receptacle is permanently attached to the spine. In the example illustrated, each tab 46 has a hole (not shown) for receiving a fastener such as a rivet 52 extending upward from the spine.