Abstract:
A loose-leaf binder having a casing and prong-carrying spring plates and having a mechanism for readily locking and unlocking the prongs through use of a trigger including pivot projections for pivoting on and in plate apertures. Locking is accomplished by lever lugs engaging casing blisters.

Description:
This is a continuation of application Ser. No. 07/348,843 filed May 8, 1989 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     Numerous techniques for holding ring binders in the closed position have been shown in prior patents (U.S. Pat. Nos. 1,927,113; 2,061,676; 3,098,490; and 3,101,719). 
     More recently, locking mechanisms as shown in U.S. Pat. Nos. 3,884,586 and 4,813,803 have been used to prevent inadvertent opening of ring binders when subjected to forces such as bumping or dropping of the binder. 
     SUMMARY OF THE INVENTION 
     Broadly, the present invention comprises a trigger-operated locking ring mechanism including a selectively blistered arched housing, prong plates, prongs and a trigger with (1) depending projections to accomplish, during opening and closing, pivoting with respect to the plates; (2) outer wings to limit trigger travel; and (3) upper lugs angled and configured to provide locking with complementary blistered-formed recesses in the arched housing. 
     It is a feature that the trigger is pivotally controlled during later stages of its closing to provide secure locking of the mechanism and when closed is held between plate pivots and the blistered housing firmly enough to resist unintended opening. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a portion of the ring binder including the locking ring mechanism of the present invention; 
     FIG. 2 is an end elevational view of the trigger alone as positioned in FIG. 2; 
     FIG. 3 is an end elevational view of the mechanism in a closed position; 
     FIG. 4 is a partial bottom view of the mechanism in the closed position; 
     FIG. 5 is a cutaway elevational view of the mechanism in an open position; 
     FIG. 6 is a partial plan view of the mechanism including the trigger in open position; and 
     FIG. 7 is a sectional view along line 7-7 of FIG. 5. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIGS. 1-7, the loose-leaf binder mechanism 9 of the present invention includes an elongated arched case housing member 10, a pair of elongated spring hinge plates 11 and 12 each of which carries two or more rings 13 composed of mating ring halves 13a, 13b, and a swingable trigger lever 14. Case member 10 and hinge plates 11 and 12 are made of a relatively stiff spring-like metal or other suitable material. The binder mechanism 9 is secured to cover spine 16 of a loose-leaf cover 17 by means of rivets 18 extending through openings 18a in hinge plates 11, 12 to connect case 10 and book cover 17 together. Case 10 includes longitudinal edges 19 curled to form elongated hinge pockets 21 (FIG. 3) and bent-down case ends 10a and 10b. 
     The inner longitudinal edges of hinge plates 11, 12 abut each other along their length (line A of FIG. 6) with their upper surfaces 11a, 12a facing toward each other in the ring prong closed position. In the ring-open position (FIG. 5) hinge plates 11, 12 have their upper surfaces 11a, 12a facing away from each other; each pair of aligned ring halves 13a, 13b being thereby spread apart to permit insertion or removal of loose-leaf sheets. Plates 11 and 12 have end notches 11n, 12n and the plates are configured to be spaced apart for a distance at their ends to create opening 15 (FIG. 4). 
     Turning to FIGS. 2 and 7, the trigger lever 14 includes horizontal body portion 22, an upper handle portion 23 and a lower transversely generally arcuate skirt member 24 in turn including center skirt portion 24a and wing portions 24b and 24c, all portions vertically oriented in the locked position (FIGS. 1 and 2). Skirt 24 has upper profile surface 24u which conforms generally to the arched curvature of case 10 (FIGS. 4 and 5) with the exception of lugs 44a, 44b as further explained. Skirt member 24 extends downwardly in generally parallel orientation with handle 23 though offset from handle 23 by body portion 22 (FIG. 7). Case-engaging surface 24u including lugs 44a, 44b frictionally engages the underside of case 10 during movement of the trigger lever 14 to and from its locked position. Proper clearance between lower portion 22, surface 24c, and case 10 together with flexibility of case 10 eliminates the possibility of preventing or restricting proper lever movement. 
     Referring in particular to FIG. 2, lower body edge profile 24l of trigger portion 24 includes outer wing elements 33a, 33b and inner lug pivot projections 34a, 34b. The outer wings 33a, 33b engage the undersides 11b, 12b of plates 11 and 12 when trigger 14 is fully open. Lug projections 34a, 34b ride during trigger movement above, near or around prong plate apertures 30a, 30b in plates 11 and 12, respectively (FIG. 4). The lower body edge profile 24l of body portion 22 also carries a centrally located T-shaped plate control element 38 which curls backward toward the vertical plane of trigger 14 when locked and plate control element 38 lies in a notched opening 15. A similar trigger, a plate opening and other parallel parts and features are preferably positioned at the opposite end of the mechanism for duplicative operation. 
     Turning to FIGS. 3-6, trigger 14, upper spaced-apart lugs 44a, 44b are shaped, angled and positioned to locate in recesses 40a, 40b created under casing blisters 45a, 45b when trigger 14 is moved to closed and locked position. The blisters and lugs lie at an angle to longitudinal line A in the range of 15° to 45° or more. Casing 10, carrying blisters 45a, 45b, flexes as required to permit lugs 44a, 44b to enter and, during opening, to be moved out of the blisters. Engagement of lugs 44a, 44b in recesses 40a, 40b formed by and below blisters 45a, 46a, as complimentarily configured, provides greater resistance to the binder opening when dropped or otherwise subjected to large forces. Recesses 40a, 40b are preferably sized to receive lugs 44a, 44b in a snug fit with the blister walls of the recesses engaging the lugs at various locations. 
     Finally, FIG. 7 shows trigger 14 fully opened with wings 33a, 33b including wing toes 35a, 35b touching at point B the bottoms 11b, 12b of plates 11, 12. 
     In operation of the mechanism from fully opened to locked, trigger handle 23 of trigger 14 is grasped and is operated to move trigger 14 from its open position (FIG. 7) to its engaged locked position (FIG. 3). During this travel, lugs 34a, 34b, initially outside of apertures 30a, 30b, enter apertures 30a, 30b and engage the circumferential sides 36a, 36b of apertures 30a, 30b, respectively at various locations thereon to provide a pivot area in which lugs 34a, 34b operate to control the area about which lever 14 pivots during its travel from its open positions to and including its fully locked position. In the fully locked position, lugs 34a, 34b will preferably be oriented against those portions of surfaces 36a, 36bclosest to lever 14 (FIG. 4). Trigger lever 14 is held in its locked or closed position by lugs 44a, 44b engaged in recesses 40a, 40b below blisters 44a, 44b and further by the close positioning of body portion 22 along the underside of case 10. To move trigger 14 to its unlock or open position sufficient force is required to be applied to trigger portion 23 to distort, bend and flex case 10, blisters 44a, 44b, plates 11, 12 and other parts of the mechanism to allow lug projections 44a, 44b to move into or out of blister recesses 40a, 40b. 
     The prongs 13 can be opened or closed directly by pulling or pushing on the prong halves 13a, 13b and the prongs can be opened or closed through movement of the trigger 14 which carries lever action through element 38 to lift or depress the plates.