Loose leaf binder

Claim 1

In a loose leaf binder having a backbone including two hinged together L-Shaped halves having integral end portions, covers hinged to the backbone, a linkage arrangement mounted on the backbone and cooperating therewith to permit the backbone to be placed in and held in a multiplicity of positions the improvement comprising: a. at least one linkage arrangement having two flexible arms each pivotably mounted at one end to an L-shaped backbone half adjacent to a flexible displaceable end portion thereof with the other ends of the arms being pivotably connected together; b. lug means positioned on each of said flexible arms; c. said adjacent end portions each having at least three lug-receiving recesses disposed radially away from the hinged portion of the respective L-shaped backbone halves, said recesses comprising: 1. a first recess immediately adjacent said hinged portion which is of an area substantially larger than the area of said lug means and is of a depth less than the length of said lug means and having the side farthest from said hinge portion sloping to essentially zero depth; 2. a second recess adjacent said first recess which is of an area only slightly larger than the area of said lug means and is of a depth approximately equal to or greater than the length of said lug means; and 3. at least one additional recess similar in area and depth to said second recess; d. said lug means cooperating with the first recess, the second recess, and the additional recess, whereby the closing of said backbone halves causes said lug means to move from said first recess into said second recess so that the binder is held open in one position and further closing of said backbone halves to cause said lug means to move to said additional recess to that the binder is held in a closed position, e. said lug means having an angled cam surface to assist in the separation of the lug means from the lug receiving recess during closing of the binder, f. said linkage arrangement and said end portions being readily displaced toward and away from one another by displacement, deformation and flexing of the binder due to forces applied to the linkage arrangement and backbone halves either intentionally or accidentally, and g. said backbone including the L-shaped halves and end portions being formed integrally of plastic material.