The present invention pertains to binder cases for carrying and displaying sheet material samples and, more particularly, to an expandable ring binder which can accommodate two separate material-holding ring metals in a manner allowing relative lateral movement between them.
Loose leaf ring binders are old and well known. They are used to demountably attach sheets or layers of various types of material within a case or cover, so that they are protected and easily transportable, but may be readily accessed for viewing and removal when the cover is open. Ring binders with relatively large diameter rings are often used to carry and display samples of bulky sheet materials, such as wall coverings, ribbons, carpeting, fabrics and the like. It is also known to mount a pair of loose leaf binder rings, commonly called ring metals, in spaced parallel relation to increase the capacity of the binder or case. Typically, two adjacent ring metals are mounted in fairly close spaced parallel relation on a single panel of the binder, such as the inside of the back or backbone of the binder. This tends to crowd the sets of samples attached to the adjacent ring metals and makes complete access to individual samples difficult because of interference from the stack of samples attached to the adjacent ring metal. This compact arrangement not only often restricts full view of the sample, but may also inhibit removal of samples from the binder.
It would be desirable, therefore, to utilize a double ring metal binder for the convenience and compact storage which it provides, but which would also provide freer and more open access to the samples of materials hung on the rings. In particular, it would be desirable if the materials on each ring metal could be flipped in either direction and lie flat without interfering contact with the adjacent ring metal and samples attached thereto.