# Patent

## Title
Ring binder mechanism

## Abstract

A ring binder mechanism includes an elongate plate having a longitudinal axis. Hinge plates are supported by the plate for pivoting relative to the elongate plate. Ring members are mounted on the hinge plates and moveable between a closed position and an open position. A control structure is supported by the elongate plate and controllably pivots the hinge plates to move the ring members between the closed and open positions. The control structure has a travel bar connected to the hinge plates for moving the hinge plates between the closed and open positions. A spring biases the travel bar toward the closed position.

## Background
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. patent application Ser. No. 11/140,728, filed May 31, 2005, which is a continuation of U.S. patent application Ser. No. 10/323,052, filed Dec. 18, 2002, now U.S. Pat. No. 7,296,946, which is a continuation-in-part of U.S. patent application Ser. No. 09/683,205, filed Nov. 30, 2001, now U.S. Pat. No. 6,749,357, the entire disclosures of which are hereby incorporated by reference.


BACKGROUND OF THE INVENTION
This invention relates to binders for holding loose leaf pages, and in particular to an improved mechanism for opening and closing binders.
A ring binder retains loose leaf pages, such as hole-punched papers, in a file or notebook. It features ring members for retaining the papers which may be selectively opened to add or remove papers, or closed to retain papers while allowing them to be moved along the ring members. Levers are typically provided on both ends of the binder for moving the ring members between the open and closed positions.
One drawback to ring binders of the prior art is that when ring members are being closed, they snap shut with a strong magnitude of force which can cause injury. When ring members are fully closed, that strong clamping force is necessary to securely lock the binder and prevent its unintentional opening. Unfortunately, that magnitude of force is also applied to the ring members while they are being opened or closed, causing difficulty in opening and closing the ring members, as well as the hazardous snapping action. Further, the clamping force within each ring is not uniform with the clamping force in other rings, causing uneven movement and potentially resulting in gaps on closed rings.
Another drawback to ring binders of the prior art is that mounting posts securing the binder to a cover often interfere with operation of components of the binder. For example, some binders have control slides operatively connected to levers for movement of the control slide lengthwise of the binder to open and close ring members. The control slides, however, must be specially formed to receive the mounting post through the control slides in order to operate. Manufacturing ring binders with these control slides can be time consuming and costly.
Accordingly, it would be beneficial to provide a ring binder in which a control slide is operatively connected to a lever by a connector capable of transmitting force from the lever to the control slide around a mounting post without requiring the control slide to be specially formed to receive the mounting post.
SUMMARY OF THE INVENTION
A ring binder mechanism has an elongate plate having a longitudinal axis. Hinge plates are supported by the plate for pivoting motion relative to the elongate plate. The mechanism has rings that include ring members moveable by the hinge plates between a closed position wherein the ring members of each ring form a substantially continuous, closed loop, and an open position wherein the ring members of each ring form a discontinuous, open loop. A travel bar is supported for movement in translation relative to the elongate plate and operatively connected to the hinge plates for moving the ring members between the closed and open positions. Pivoting movement of the hinge plates from the closed position to the open position is blocked when the travel bar is in the closed position. A spring is arranged to bias the travel bar toward the closed position.
Another aspect of the invention is a ring binder mechanism having an elongate plate. The elongate plate has a longitudinal axis and two generally opposite longitudinal edges. Hinge plates are supported by the plate between the two edges for pivoting motion relative to the elongate plate. The mechanism has rings that include ring members moveable by the hinge plates between a closed position wherein the ring members of each ring form a substantially continuous, closed loop, and an open position wherein the ring members of each ring form a discontinuous, open loop. A control structure is supported by the elongate plate for movement relative to the elongate plate for controllably pivoting the hinge plates to thereby move the ring members between the closed and open positions. The control structure includes a travel bar operatively connected to the hinge plates and movable in translation relative to the elongate plate for moving the hinge plates between the closed and open positions. A spring is arranged to bias the travel bar toward the closed position for locking the hinge plates in the closed position.
Still another aspect of the invention is a ring binder mechanism. The mechanism has an elongate plate having a longitudinal axis and two generally opposite longitudinal edges. Hinge plates are supported by the plate between the two edges for pivoting motion relative to the elongate plate. The mechanism has rings including ring members moveable by the hinge plates between a closed position wherein the ring members of each ring form a substantially continuous, closed loop, and an open position wherein the ring members of each ring form a discontinuous, open loop. A control structure is supported by the elongate plate for movement relative to the elongate plate for controllably pivoting the hinge plates to thereby move the ring members between the closed and open positions. The control structure includes a travel bar operatively connected to the hinge plates and movable in translation relative to the elongate plate for moving the hinge plates between the closed and open positions. The control structure also includes an actuating lever. The lever is operatively connected to the travel bar such that pivoting motion of the lever produces movement of the travel bar generally lengthwise of the elongate plate. The control structure is adapted to block pivoting movement of the hinge plates to open the rings when the ring members are in the closed position. A spring is arranged to bias the travel bar toward the closed position.
Other objects and features of the present invention will be in part apparent and in part pointed out hereinafter.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective of a ring binder mechanism of a first embodiment of the present invention;
FIG. 2 is an exploded perspective thereof;
FIG. 3 is a fragmentary perspective of the mechanism with an elongate plate thereof removed and in a closed and unlocked position;
FIG. 4 is a fragmentary longitudinal section of the mechanism at the closed and unlocked position;
FIG. 5 is a view similar to FIG. 3 with the mechanism at an open position;
FIG. 6 is a view similar to FIG. 4 with the mechanism at the open position;
FIG. 7 is a view similar to FIG. 3 with the mechanism at a closed and locked position;
FIG. 8 is a view similar to FIG. 4 with the mechanism at the closed and locked position;
FIG. 9 is a bottom perspective of the ring binder of FIG. 1 at the closed and locked position with one hinge plate removed;
FIG. 10 is a view similar to FIG. 9 with the mechanism at the open position;
FIG. 11 is a perspective of a notebook incorporating the ring binder mechanism;
FIG. 12 is an enlarged perspective of a connecting link;
FIG. 13 is a section taken on line 13-13 of FIG. 8;
FIG. 14 is a bottom plan of a travel bar of the mechanism of the first embodiment;
FIG. 15 is a bottom plan view of a ring binder mechanism according to a second embodiment of the present invention with the mechanism at the closed position;
FIG. 16 is a view similar to FIG. 15 with the mechanism at the open position;
FIG. 17 is an exploded perspective of the second embodiment;
FIG. 18 is an enlarged perspective of a travel bar of the second embodiment;
FIG. 18A is an enlarged bottom exploded perspective of the travel bar of FIG. 18 showing a tab unassembled from the travel bar;
FIG. 18B is an enlarged bottom perspective of the travel bar of FIG. 18A showing the tab assembled to the travel bar;
FIG. 18C is a section taken along line 18C-18C of FIG. 18B;
FIG. 19 is an enlarged perspective of a second version of the travel bar of the second embodiment;
FIG. 20 is an enlarged perspective of a third version of the travel bar of the second embodiment;
FIGS. 21 and 22 are a perspective and an end elevation, respectively, of a binder mechanism according to a third embodiment of the present invention having rings of a first slanted D shape; and
FIGS. 23 and 24 are a perspective and an end elevation, respectively, of a binder mechanism according to a fourth embodiment of the present invention having rings of a second slanted D shape.



Corresponding reference characters indicate corresponding parts throughout the views of the drawings.
DETAILED DESCRIPTION
Referring now to the drawings and in particular to FIG. 1, a ring binder mechanism according to the present invention for retaining loose leaf pages is indicated generally at 30. The mechanism 30 includes an elongate plate 32 and three rings, each indicated generally at 34, for holding loose leaf pages.
The plate 32 is shaped as an elongated rectangle with a uniform, generally arch-shaped elevated profile having at its center a raised plateau 36. The plate 32 has a longitudinal axis 38, two generally opposite longitudinal edges 40, and two generally opposite transverse ends 42. A bent under rim 44 (FIG. 9) is formed along the longitudinal edges 40. The elongate plate 32 is made of metal or other suitable material which is sufficiently rigid to provide a stable mount for other components of the mechanism, while being lightweight to conserve material and manufacturing costs. Two openings 46 (FIG. 2) are provided for receiving and attaching mounting posts 48 to secure the mechanism to a file or notebook 50 (FIG. 11), and six additional holes 52 are positioned along the longitudinal edges 40 to receive the rings therethrough. Mechanisms having plates or housings of other shapes, including irregular shapes, or housings which are integral with a file or notebook, do not depart from the scope of this invention.
Each of the three rings 34 include two half ring members 54 which are movable between a closed position (FIGS. 1 and 3) wherein each ring member forms a continuous, closed loop for retaining loose leaf pages, and an open position (FIG. 5) wherein each ring member forms a discontinuous, open loop suitable for adding or removing pages. The ring members 54 are formed of a conventional, cylindrical rod of a suitable material such as steel. Although both ring members 54 of each ring 34 are movable in the illustrated embodiment, a mechanism having a movable ring member and a fixed ring member does not depart from the scope of this invention. Further, a mechanism with a different number of rings, greater or less than three, does not depart from the scope of this invention.
The ring members 54 are mounted on hinge plates 56 (FIGS. 2 and 3) which are supported by the elongate plate 32 for pivotal motion to move the ring members between the closed and open positions. The hinge plates 56 are mounted in parallel arrangement and attached to each other for pivotal motion along adjoining longitudinal edges to form a hinge 58. Two pairs of aligned notches 60 in the hinge plates 56 are positioned along the hinge and define openings, the use of which will be explained hereinafter. Each hinge plate 56 has an outer longitudinal edge margin 62 opposite the hinge which is received in the corresponding bent under rim 44 of the elongate plate 32. The longitudinal edge margins 62 are free to move within the rim 44 to allow pivoting movement of the hinge plates 56 on the hinge 58. The elongate plate 32 provides a small spring force to bias the hinge plates 56 to pivot away from a co-planar position (i.e., toward either the closed position or the open position). However, the biasing force provided by the elongate plate 32 is substantially smaller than on conventional ring binder mechanisms, and the plate provides effectively no clamping force to hold the ring members 54 in the closed position as with conventional mechanisms. The elongate plate 32 provides a force which is as small as it can be while still supporting the hinge plates 56. Each hinge plate 56 also has several locating cutouts 64 along the outer longitudinal edge margin 62 for a purpose described hereinafter.
A unique control structure indicated generally at 66 is provided for controllably pivoting the hinge plates 56 and thereby moving the ring members 54 between the closed and open positions, as well as for controllably locking the ring members at the closed position. The control structure 66 includes a single actuating lever 68 at one end of the mechanism, a travel bar 70, and two connecting links 72 which are supported by the elongate plate 32 and are movable relative to the elongate plate. The connecting links 72 operatively connect the travel bar 70 to the hinge plates 56.
The actuating lever 68 selectively moves the ring members 54 between the open and closed positions and moves the mechanism to a locked position. The lever 68 is pivotally mounted by a hinge pin 74 to one end 42 of the elongate plate 32 in a position readily accessible for grasping and moving the lever. The opposite end 42 of the elongate plate is free from any actuator, although it is understood that a mechanism with two levers does not depart from the scope of this invention. The lever 68 is operatively connected to the travel bar 70 such that application of force to the lever produces movement of the travel bar generally lengthwise of the elongate plate 32. The pivotal motion of the lever 68 provides for easier application of force by an operator when moving the travel bar 70 than it would be to translate the bar directly as by pushing or pulling, and does so without the bar protruding from the elongate plate. A suitable rigid material or combination of materials, such as metal or plastic, forms the lever 68.
An intermediate connector 76 is pivotally connected to the lever 68 and to the travel bar 70 for pivoting motion relative to both the lever and travel bar. Force is transmitted from the lever 68 to the travel bar 70 through the intermediate connector 76. The intermediate connector 76 has an elongate slot 78 for allowing the intermediate connector to move while receiving a mounting post 48 through the slot. The slot 78 allows transmission of force around the post 48 while keeping direction of force along a centerline of the intermediate connector 76. The intermediate connector 76 has a tabbed end 80 for being received in a slot 82 on an end of the travel bar 70 for permitting relative pivoting motion. A hinge pin 84 attaches the intermediate connector 76 to the lever 68.
The travel bar 70 (FIG. 14) is elongate in shape and disposed in generally parallel arrangement with the longitudinal axis 38 of the elongate plate 32. It is movable generally lengthwise of the elongate plate, being pivotally supported by the connecting links 72. The travel bar 70 is housed within the elongate plate 32 behind the raised plateau 36. In one embodiment, the travel bar 70 has the shape of a rigid channel, with a flat web 86 and downwardly turned side flanges 88.
Two mounts, indicated generally at 90, are on the travel bar 70 for pivotally attaching the travel bar and connecting links 72. Each mount 90 includes stops 92, 94 (FIG. 10) formed by punching and bending portions of the web 86. Two stops 92 are arranged on a first longitudinal side of the mount 90 and two stops 94 on the opposite side. The stops limit an angular extent of pivotal motion of the connecting link 72 relative to the travel bar 70. Each stop 92, 94 has an angled surface configured for engagement by the connecting link 72. The stops are directionally configured, i.e., the angle of surfaces on stops 92 differs from the angle of surfaces on stops 94 such that a maximum relative angle between the connecting link and travel bar may be greater in one longitudinal direction than in the opposite longitudinal direction. Corresponding notches 96 (FIG. 2) are formed in the flanges 88 of the travel bar 70 at positions adjacent each mount, forming a slot transverse a longitudinal axis of the bar for permitting free pivotal motion of the connecting links 72.
Referring to FIG. 12, each connecting link 72 has a tongue 98 projecting from the top center of the link which is pivotally received in the mount 90, between the stops 92 and 94. The tongue 98 pivots about an axis transverse to the longitudinal axis of the travel bar 70. An upper peripheral edge of the tongue 98 is generally straight and configured to engage the mount 90 for attaching the connecting link 72 to the travel bar 70 in loose fitting relation such that the bar is movable generally lengthwise of the elongate plate 32 while the connecting link pivots with respect to the elongate plate. The tongue 98 is bent at a slight angle relative to the center of the link 72, as shown at line 100 in FIG. 12. That angle inhibits occurrence of the link 72 becoming stopped at a vertical position with little or no tendency to move away from that position when force is oriented generally vertically. The connecting link 72 has two lugs 102 for engaging upper surfaces of the two hinge plates 56 adjacent to the hinge 58. A tab 104 depends from the lower center of the connecting link 72 for being received through the opening defined by the aligned notches 60 at the hinge. The tab 104 is in loose fitting relation with the hinge plates 56 for attaching the connecting link 72 to the hinge plates. A retainer 106 at the bottom of the tab 104 is wider than the opening at the notches 60 to prevent the tab 104 from being fully withdrawn from the opening. The tab 104 is configured to move toward and away from the hinge plates 56 while permitting the connecting link 72 to pivot with respect to the hinge plates. When the link 72 pivots to where the retainer 106 engages the hinge plates 56, the retainer pivots the hinge plates to move the ring members 54 to the open position.
Locating arms 108 extend laterally outwardly from opposite sides of the connecting link 72 for extending through the locating cutouts 64 in the hinge plates 56. The arms 108 attach the link 72 to the hinge plates 56 and locate the link against canting movement, that is, movement about a vertical axis perpendicular to the longitudinal axis 38 of the elongate plate 32. However, ends of the arms 108 are received sufficiently loosely in the locating cutouts 64 so as not to interfere with the pivoting motion of the connecting link 72.
Preferably, the connecting links 72 are formed of a suitable rigid material, such as metal or plastic. It is understood that mechanisms with links formed of a non-rigid material do not depart from the scope of this invention. Further, a mechanism having a different number of connecting links (i.e., greater or less than two) does not depart from the scope of this invention.
The connecting links 72 are at spaced apart locations and positioned longitudinally relative to the rings 34 such that force applied through the lever 68 is distributed generally uniformly among the rings. In the embodiment of FIGS. 9 and 10, there are three rings 34 and two connecting links 72, the links being symmetrically positioned in alternating relation relative to the rings to transmit force to the hinge plates 56 which is generally equally distributed among the three rings. The symmetric positioning of the connecting links 72 avoids problems of uneven force distribution to the rings as on mechanisms of the prior art. The links 72 are positioned closer to the endmost rings 34, each at a spacing between about one-fourth and one-third of the distance between the endmost and centermost rings. It will be understood that other quantities of connecting links 72 and other spacings do not depart from the scope of this invention.
The components of the mechanism 30 are made of a suitable rigid material, such as a metal (e.g., steel). Mechanisms made of non-metallic materials, specifically including a plastic, do not depart from the scope of this invention.
In operation, the control structure 66 is configured to selectively place the mechanism 30 at three primary positions:
First position: Ring members 54 open (FIGS. 5 and 6);
Second position: Ring members 54 closed and unlocked (FIGS. 3 and 4);
Third position: Ring members 54 closed and locked (FIGS. 7 and 8).
In order to move from the first position to the second and third, an operator applies force to the lever 68 to progressively pivot the lever upwardly. That pulls the intermediate connector 76 and travel bar 70 such that they move toward the end 42 of the elongate plate 32 having the lever. As the travel bar 70 moves, both connecting links 72 are simultaneously and pivotally moved to a more upright position. For instance, typical angles A (FIGS. 4, 6, and 8) of the connecting link 72 relative to the elongate plate 32 are about 30 degrees at the first position, about 45 degrees at the second position, and about 95 to 100 degrees at the third position. Other angles do not depart from the scope of this invention.
The angle of the connecting links 72 in turn controls the position of the hinge plates 56. When closing the ring members 54, the lugs 102 on the connecting links engage the upper surfaces of the hinge plates 56, pushing them downward to pivot the hinge plates and thereby close the ring members. Conversely, when opening the ring members 54, the tabs 104 of the connecting links engage the lower surfaces of the hinge plates 56 to pivot the hinge plates in the opposite direction.
At the second, unlocked position, any force which tends to open the ring members 54 is not opposed. Because the hinge plates 56 receive substantially no tension from the elongate plate 32, a light finger pressure on the ring members is sufficient to move the ring members 54 to the first, open position, or back to the second, closed and unlocked position. Such force needs only overcome internal friction of the mechanism and the small spring force biasing the hinge plates 56 away from a co-planer position. There is no strong snapping motion as on conventional mechanisms. The force pivots the hinge plates 56, pushing up on the lugs 102 of the connecting links 72, and thereby pivoting the links to a different angle A.
A strong clamping force is not being applied while the ring members 54 in the rings 34 move between the first (open) and second (closed and unlocked) positions. Unlike binders of the prior art, the elongate plate 32 does not provide significant tension to the hinge plates and rings. Accordingly, the force is relatively less when the ring members are moving. That permits the ring members to be easily opened or closed using less strength by an operator. It also inhibits injury should the operator inadvertently place a finger or hand in position between ring members 54 while they are being clamped together.
When the connecting links 72 reach an angle A of 90 degrees (not shown), which is between the second and third positions and substantially closer to the third position, the mechanism 30 is at a critical locked position. As shown in FIG. 13 for the third (locked) position, force tending to open the ring members 54 is firmly opposed by the connecting links 72 which are vertically oriented. When the hinge plates 56 push up on the lugs 102, there is little tendency to pivot or move the mechanism toward the open position because force applied to the ring members 54 urges the connecting links to move vertically upward. That motion is strongly opposed by the mechanism because the links push up on the travel bar 70 which is captured beneath the elongate plate 32. Clamping force in the rings 34 is maximized because the connecting links 72 are perpendicular between the travel bar 70 and hinge plates 56, providing a maximum spacing between those components to apply maximum force to the hinge plates. At the third, locked position the mechanism is moved to where the connecting links 72 reach an angle A slightly past the critical position (i.e., to 95 to 100 degrees) to insure stability and avoid inadvertent movement to an unlocked position. The links 72 engage the stops 92 at that position.
As shown in FIG. 11, the ring binder mechanism may be mounted on a cover of a notebook 50. The cover is movable to selectively cover and expose loose leaf pages retained on the rings 34.
One method according to the present invention opens or closes the ring binder mechanism 30 having ring members 54. The method comprises the steps of mounting the ring members 54 on pivotable hinge plates 56 such that pivoting of the hinge plates moves the ring members between open and closed positions. The hinge plates 56 are operatively connected with the travel bar 70 by placing at least one pivotally movable connecting link 72 between the hinge plates and the bar such that motion of the bar produces pivotal motion of the hinge plates. Force is applied to the travel bar 70 to move the bar, thereby pivoting the connecting links 72 to open or close the ring members 54. A step of locking the mechanism 30 includes applying force to the travel bar 70 to move the bar and thereby pivot the connecting links 72 to incline the connecting links to at least the critical locked position (angle A of 90 degrees or greater) wherein opening of ring members is inhibited.
The binder mechanism 30 of the present invention effectively retains loose leaf pages. The mechanism does not snap shut with a strong force which might injure a person who inadvertently places a finger or hand between ring members as they clamp together. The ring members 54 may be moved by application of force at only one end 42 of the elongate plate, and the magnitude of force is less than on ring binders of the prior art. The mechanism distributes force generally uniformly to the three rings 34. The binder may be controllably placed in a locked position for securing loose leaf sheets.
A second embodiment of the ring binder mechanism of the present invention, generally indicated 130, is shown in FIGS. 15-20. This embodiment 130 is substantially similar to the first embodiment 30 except that the control structure, generally indicated 132, has been modified to accommodate a spring 134 for biasing the mechanism to the third position shown in FIG. 15 (ring members 54 closed and locked). As shown in FIGS. 17 and 18, a modified travel bar 140 is provided in the form of an elongate plate 142 having a turned up end 144 and three sets of turned up mounts, generally indicated 146. The turned up end 144 of the travel bar of the second embodiment 130 has a slot 148 for receiving the tabbed end of the intermediate connector 76 that is pivotally connected to the actuating lever 68 as in the previous embodiment. The mounts 146 each pivotally attach the travel bar 140 with the connecting links 72 and function to limit the angular extent of pivotal movement of the connecting links 72 relative to the travel bar. As in the previous embodiment, each mount 146 has two opposing pairs of stops, 152 and 154 respectively, each with a respective angled surface 156, 158 for engagement by the connecting link 72. In the embodiment of FIGS. 15-18, the travel bar 140 has a tab 162 mounted on a slot or opening 164 in the elongate plate 142 with a hole 166 for receiving a first end 168 of the spring 134. As shown in FIGS. 18A through 18C, the tab 162 is attached to the travel bar 140 by stamping an end portion 170 of the tab that protrudes past the opening 164 in the elongate plate 142. FIGS. 185 and 18C show the tab 162 assembled to the travel bar having the end portion 170 deformed to have a cross-sectional area greater than the opening 164 in the elongate plate 142 preventing the tab 162 from being withdrawn from the travel bar 140. FIG. 19 shows an alternative embodiment of the travel bar 140 where the tab 162 is formed as one piece with the elongate plate 142 that is struck upwardly 90 from the surface of the plate and is generally parallel with the mounts 146. FIG. 20 shows another embodiment of the travel bar 140 where the integral tab 162 is struck upwardly less than 90 from the surface of the plate 142 so that the tab is perpendicular to the mounts 146. It will be understood that embodiments of FIGS. 19 and 20, including tabs 162 that are integral to the travel bar 140, are easier and less expensive to manufacture than the stamped tab illustrated in FIGS. 18 through 18C but the stamped tab provides a stronger connection to the travel bar.
As shown in FIGS. 15-17, the ring binder mechanism 130 is substantially similar to the previous embodiment in that the mechanism has two hinge plates 172 mounted in generally parallel arrangement and attached for pivotal motion along adjoining longitudinal edges 174 that form a hinge 176. The hinge plates 172 have an aperture 178 spaced in from the hinge 176 to receive a second end 180 of the spring 134. In the illustrated embodiment the aperture 178 is rectangular and is located on one of the hinge plates 172. Alternatively, the aperture 178 may comprise other shapes and sizes, but it will be understood that the aperture that may encompass one or both of the longitudinal edges 174 of the hinge plate 172. As shown in FIGS. 15-17, each hinge plate 172 has an inner longitudinal edge cutout 184 which cooperates with the cutout of the other hinge plate to define a cavity 186 for accommodating the body of the spring 134 and the tab 162 on the travel bar 140 that receives the first end 168 of the spring. Each hinge plate 172 has three sets of aligned notches 60 forming openings to accommodate the tabs 104 of the three connecting links 72.
In operation, the control structure 132 is configured to allow the same lengthwise movement of the travel bar 140 and the same pivotal movement of the connecting links 72 as in the previous embodiment. However, the mechanism 130 is configured to move directly from the first position (ring members 54 open) shown in FIG. 16, to the third position (ring members closed and locked) shown in FIG. 15. When an operator applies a force to the lever 68 to move the mechanism 130 from the first position where the ring members 54 are held open, the biasing force of the spring 134 advances the travel bar 140 toward the end 42 of the elongate plate 32 having the lever 68. Rather than staying in the second position where the ring members 54 are closed and unlocked, the mechanism is biased to the third position by the force of the spring 134 advancing the travel bar 140 to a location where the ring members are held closed. At this position, the clamping force of the rings 54 is maximized and any force tending to pivot the hinge plates 172 and open the ring members is firmly opposed by the locking forces of the control structure 132 resulting from the vertical orientation of the connecting links 72. Therefore, to unlock the mechanism 130, a force sufficient to oppose the spring biasing force and advance the travel bar 140 to a location corresponding with the first position of the mechanism must be applied to the actuator 68 rather than the ring members 54 so that the travel bar can pivot the connecting links 72 against the hinge plates 172 causing the ring members to open. At the first position, an external force on the actuator 68 is not required to hold the ring members 54 open because the internal forces of the control structure 132 are sufficient to overcome the force of the spring 134 to maintain the travel bar 140 at a position toward the end 42 of the elongate plate 32 not having the actuator.
A third embodiment 220 of the present invention is shown in FIGS. 21 and 22. The rings 34 of the third embodiment have a shape generally in the form of a slanted letter D, with a first ring member 222 which is a generally straight post at an angle of inclination, and a second ring member 224 which is generally semicircular in shape.
A fourth embodiment 230 of the present invention is shown in FIGS. 23 and 24. The rings 34 of the fourth embodiment have an alternate shape of another slanted D. It is understood that a mechanism having other shapes of rings does not depart from the scope of this invention. Also, the embodiments of FIGS. 22-24 could have control structures of either of the first two embodiments of the present invention.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results obtained.
When introducing elements of the present invention, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
As various changes could be made in the above without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

## Claims

1. A ring binder mechanism, the mechanism comprising:
an elongate plate having a longitudinal axis;
hinge plates supported by said plate for pivoting motion relative to the elongate plate;
rings including ring members moveable by the hinge plates between a closed position wherein the ring members of each ring form a substantially continuous, closed loop, and an open position wherein the ring members of each ring form a discontinuous, open loop;
a travel bar supported for movement in translation relative to the elongate plate and operatively connected to the hinge plates for moving the ring members between the closed and open positions, pivoting movement of the hinge plates from the closed position to the open position being blocked when the travel bar is in the closed position; and
a spring arranged to bias said travel bar toward the closed position.

2. A ring binder mechanism as set forth in claim 1 wherein the spring is attached to the travel bar and one of the hinge plates.

3. A ring binder mechanism as set forth in claim 2 wherein the spring is a coil spring which is elongated lengthwise of the elongate plate when the hinge plates are moved from the closed position to the open position.

4. A ring binder mechanism as set forth in claim 2 wherein the travel bar is part of a control structure and the control structure further comprises a tab projecting outwardly from the travel bar, an end of the spring being attached to the tab.

5. A ring binder mechanism as set forth in claim 4 wherein the tab comprises a plate having a portion received in a slot in the travel bar and secured therein.

6. A ring binder mechanism as set forth in claim 4 wherein the tab is formed as one piece with the travel bar.

7. A ring binder mechanism as set forth in claim 6 wherein the tab comprises an upwardly struck piece of the travel bar having opposite major surfaces.

8. A ring binder mechanism as set forth in claim 7 wherein the major surfaces are generally parallel to a longitudinal axis of the travel bar.

9. A ring binder mechanism as set forth in claim 7 wherein the major surfaces are generally perpendicular to a longitudinal axis of the travel bar.

10. A ring binder mechanism as set forth in claim 1 wherein the travel bar is part of a control structure and said control structure further comprises a connecting link pivotally connecting the travel bar to the hinge plates for moving the hinge plates between said closed and open positions.

11. A ring binder mechanism as set forth in claim 1 wherein said elongate plate has two generally opposite longitudinal edges, the hinge plates being supported loosely between said two edges such that the hinge plates are not biased to the open or closed position by the elongate plate.

12. A ring binder mechanism as set forth in claim 1 wherein the travel bar is part of a control structure, the control structure further comprising an actuating lever operably connected to the travel bar so pivoting movement of the actuating lever produces longitudinal movement of the travel bar in the housing.

13. A ring binder mechanism as set forth in claim 10 wherein the connecting link is pivotally attached to the travel bar and pivotally attached to at least one of the hinge plates.

14. A ring binder mechanism as set forth in claim 13 wherein the control structure further comprises an actuating lever pivotally mounted on the elongate plate in a position for grasping to pivot the lever, the lever being operatively connected to the travel bar such that pivoting motion of the lever produces movement of the travel bar generally lengthwise of the elongate plate.

15. A ring binder mechanism as set forth in claim 1 in combination with a cover, the ring binder mechanism being mounted on the cover, the cover being movable to selectively cover and expose any loose leaf pages retained on the rings.

16. A ring binder mechanism as set forth in claim 1 wherein said rings have a generally circular shape.

17. A ring binder mechanism as set forth in claim 1 wherein said rings have a generally slanted D shape.

18. A ring binder mechanism as set forth in claim 1 wherein the travel bar is part of a control structure said control structure further comprises a pivotally movable actuator located generally at one end of the elongate plate and wherein said spring is releasably attached to said control structure and at least one of said hinge plates.

19. A ring binder mechanism as set forth in claim 1 wherein the travel bar is part of a control structure and the control structure further comprises an actuator and a connecting link separate from the actuator, the connecting link being pivotally connected to the travel bar and pivotally connected to at least one of the hinge plates.

20. A ring binder mechanism as set forth in claim 1 wherein the spring is releasably connected to the travel bar.

21. A ring binder mechanism, the mechanism comprising:
an elongate plate having a longitudinal axis and two generally opposite longitudinal edges;
hinge plates supported by said plate between said two edges for pivoting motion relative to the elongate plate;
rings including ring members moveable by the hinge plates between a closed position wherein the ring members of each ring form a substantially continuous, closed loop, and an open position wherein the ring members of each ring form a discontinuous, open loop;
a control structure supported by the elongate plate for movement relative to the elongate plate for controllably pivoting said hinge plates to thereby move the ring members between the closed and open positions, the control structure comprising a travel bar operatively connected to the hinge plates and movable in translation relative to the elongate plate for moving the hinge plates between the closed and open positions; and
a spring arranged to bias said travel bar toward the closed position for locking the hinge plates in the closed position.

22. A ring binder mechanism as set forth in claim 21 wherein at least a portion of the edges of the elongate plate are bent under to capture the hinge plates.

23. A ring binder mechanism as set forth in claim 21 wherein the spring is a coil spring which is elongated lengthwise of the elongate plate when the hinge plates are moved from the closed position to the open position.

24. A ring binder mechanism as set forth in claim 21 wherein said rings have a generally slanted D shape.

25. A ring binder mechanism as set forth in claim 21 in combination with a cover, the ring binder mechanism being mounted on the cover, the cover being movable to selectively cover and expose any loose leaf pages retained on the rings.

26. A ring binder mechanism, the mechanism comprising:
an elongate plate having a longitudinal axis and two generally opposite longitudinal edges;
hinge plates supported by said plate between said two edges for pivoting motion relative to the elongate plate;
rings including ring members moveable by the hinge plates between a closed position wherein the ring members of each ring form a substantially continuous, closed loop, and an open position wherein the ring members of each ring form a discontinuous, open loop;
a control structure supported by the elongate plate for movement relative to the elongate plate for controllably pivoting said hinge plates to thereby move the ring members between the closed and open positions, the control structure comprising a travel bar operatively connected to the hinge plates and movable in translation relative to the elongate plate for moving the hinge plates between the closed and open positions; the control structure further comprising an actuating lever, the lever being operatively connected to the travel bar such that pivoting motion of the lever produces movement of the travel bar generally lengthwise of the elongate plate, wherein the control structure is adapted to block pivoting movement of the hinge plates to open the rings when the ring members are in the closed position; and
a spring arranged to bias said travel bar toward the closed position.

27. A ring binder mechanism as set forth in claim 26 wherein the spring is a coil spring which is elongated lengthwise of the elongate plate when the hinge plates are moved from the closed position to the open position.

28. A ring binder mechanism as set forth in claim 26 wherein said rings have a generally slanted D shape.

29. A ring binder mechanism as set forth in claim 26 in combination with a cover, the ring binder mechanism being mounted on the cover, the cover being movable to selectively cover and expose loose any leaf pages retained on the rings.

30. A ring binder mechanism as set forth in claim 26 wherein the hinge plates cooperatively define at least one opening for allowing a portion of the control structure to pass through the hinge plates.