Plastic looseleaf binder ring assembly

In a looseleaf binder ring assembly comprising a one-piece backbone formed of a resilient plastic material and having a plurality of pairs of cooperating fingers mounted thereon with the fingers of each pair facing one another and being movable between open and closed positions with respect to each other;

• said backbone having upper and lower surfaces, and said fingers each including a looseleaf holder portion extending above said upper surface and a generally vertically extending cam portion extending through the backbone to a position below said lower surface;
• a relatively flat slide bar mounted in said backbone below said lower surface for movement between first and second positions with respect to the backbone, corresponding respectively to the open and closed positions of said fingers, said slide bar having a plurality of pairs of oppositely facing cam surfaces formed thereon lying in substantially the same horizontal plane and being respectively associated with said fingers;
• each of said pairs of cam surfaces defining an upwardly opening recess receiving a portion of their associated fingers;
• said oppositely facing cam surfaces of each pair being longitudinally offset from one another to be respectively placed in engagement with their associated finger when said slide bar is moved between its first and second positions;
• one of said surfaces of each pair engaging one side of its associated finger and holding it in its open position when said bar is in its first position and the other of said surfaces of each pair engaging another side of its associated finger and holding it in its closed position when said bar is in its second position;
• wherein the improvement comprises said finger being separately formed from said backbone and each having at least one pivot pin integrally formed thereon extending transversely thereof, said backbone having a plurality of downwardly opening pockets formed therein pivotally receiving and engaging said pivot pins, said pockets having an arcuate extent of more than 180.degree. thereby to retain said pivot pins in the pockets while allowing pivotal movement thereof.

In a looseleaf binder ring assembly comprising a one-piece backbone formed of plastic material and having an inverted generally U-shaped configuration in section ;

• said backbone having a bight portion defining upper and lower surfaces, a plurality of apertures formed in its bight portion, and a plurality of pairs of cooperating fingers mounted on said backbone and extending through said apertures, the fingers of each pair facing one another and being pivotally connected to the backbone whereby the fingers are movable between open and closed positions with respect to each other;
• said fingers having upper looseleaf holding portions extending from said opening above the upper surface of the backbone and lower end portions extending generally vertically downwardly through said openings to positions below said lower surface;
• a relatively flat slide bar slidably mounted for movement between first and second positions with respect to said backbone, said positions corresponding respectively to the open and closed positions of said fingers;
• said slide bar having a plurality of finger moving members formed integrally therewith and respectively associated with the lower end of each of said fingers;
• said finger moving members each having an upwardly opening recess formed therein and generally diagonally opposed cam surfaces on opposite sides of the recesses in substantially the same horizontal plane with respect to the generally vertically extending lower end portions of their associated fingers, said cam surfaces extending angularly in said horizontal plane with respect to the direction of sliding movement of said bar;
• said lower end portions of said fingers extending into said recesses and with opposite sides thereof being respectively engaged by the generally diagonally opposed cam surfaces associated therewith in the first and second positions of the slide bar, one of said cam surfaces engaging one side of its associated finger and holding it in its open position when the slide bar is in its first position and the other of said cam surfaces engaging another side of its associated finger and holding it in its closed position when said slide bar is in its second position;
• wherein the improvement comprises said fingers being separately formed from said backbone and each having a plurality of downwardly opening pockets formed therein pivotally receiving and engaging said pivot pins, said pockets having an arcuate extend of more than 180.degree. thereby to retain said pivot pins in the pockets while allowing pivotal movement thereof.