Lever arch binder mechanism with complementary ring tips

A ring binder mechanism has D-shaped rings formed by a straight, stationary part, and a movable mating part having an arcuate shape. A recess is formed in the tip of the movable part, and a protrusion at the tip of the stationary part seats in the recess. A lateral window in the recessed tip, intersecting the recess, enables the protrusion to seat smoothly in the recessed tip notwithstanding the fact that the relative motion between the approaching tips has a large lateral component.

BACKGROUND OF THE INVENTION

This invention relates to a ring binder mechanism having an actuating crank.

Many modern ring binder mechanisms have actuating levers for opening and closing two, three or more rings. In some such devices, the levers also lock the rings closed. The typical arrangement is to attach the bottoms of the ring halves to hinged plates confined between the edges of an arcuate metal housing which provides a toggling action as the plates snap between open and closed positions.

Other devices have been proposed in which the rings are opened and/or closed by a cam-type mechanism. Prior such constructions are seen in U.S. Pat. Nos. 778,910, 2,494,898, 2,789,561, and 2,894,513. U.S. Pat. No. 778,910 discloses a two-ring binder mechanism which is opened by lifting the end of a lever which depresses a crank whose ends are the movable ends of the two rings. U.S. Pat. No. 6,637,968 shows a device more closely related to the present invention.

In most ring binder mechanisms, the opposed ring parts are both semicircular, so that when they are closed, they form substantially a circular shape. One problem with semi-circular ring parts is that they do not make it easy to load or remove large numbers of papers at once onto or off of the rings. Automatic machine loading of papers onto such rings is particularly difficult. For this reason, some prior inventors have developed rings in which one segment is straight, or almost so. With such rings, commonly called D-rings, a large group of papers can be lowered right onto the straight segments very simply and quickly. But since D-rings are not symmetrical, the tips meet to the left or right of the center plane of the mechanism and therefore approach one another not axially, but rather with a lateral component so that the line of approach is oblique to the length of the straight segment. The greater the offset, the greater the lateral component.

An oblique approach direction creates difficulty when one tip has a protrusion designed to seat within in recess in the other. With this construction, an oblique approach may result in interference between the approaching tips, preventing or impeding proper seating. The solution to this problem, until now, has been to bend the tip of the straight segment inward so that it points at the approaching tip of the arcuate segment. Bending the tip, however, works against the goal of facilitating the installation and removal of large groups of papers.

SUMMARY OF THE INVENTION

An object of the invention is to improve the operation of a crank-operated ring binder mechanism having two or more rings.

An object of the invention is to provide a ring binder mechanism having D-shaped rings of either the slanted type on non-slanted type, having a perfectly straight segment onto which large groups of papers can be easily loaded and removed.

A related object is to provide a ring tip geometry which permits the tips to approach one another at a substantial angle to their length, and to seat smoothly and without interference.

These and other objects are attained by a ring binder mechanism having a support plate, and at least two rings, each comprising a movable segment pivotally attached to the support plate and an immovable segment affixed to said support plate, and a crank for moving the rings between an open position and a closed and locked position. The crank, which is pivotally supported on the support plate for oscillation about a longitudinal axis, has one or more throws offset from the longitudinal axis. The movable ring segments are integrally attached to the crank. A leaf spring biases the crank toward a rings-closed position, and a manually operable lever moves the crank toward a rings-open position. The lever is pivotally mounted on said support plate and depresses the throw, driving the crank towards its rings-closed position, as the lever is depressed.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention is embodied in a mechanism comprising a support plate10having raised portions or plateaus, which reinforce the plate, formed by embossing. Projections12on the plateau14support the bottoms of straight, stationary ring members16,18which extend perpendicular to the support plate. The upper ends of the stationary members terminate at tips20.

A large tab22is bent perpendicularly out from the support plate. A narrow slot24is cut across the top of the space from which the tab was deformed, leaving a bridge26which is deformed slightly upward and bears against the bottom surface of a leaf spring28whose fixed end is held within the slot. The leaf spring's free end provides an upward bias against a crank described below.

A pin30is staked or welded to the top of the tab, facing the spring side.

One end of an actuating lever32is pivotally mounted on the pin, whose head is flattened to retain the lever.

The lever has a first end segment34, an intermediate segment36perpendicular to the first end, and a second end segment38perpendicular the intermediate segment. A flattened tip40extends from the end of the second end, parallel to the intermediate segment. The lever32pivots in the center plane of the device. It has a circumferentially grooved nylon roller42fixed on a headed pin44which is fixed to and extends from the lever near the intersection of the first end segment and the intermediate segment. The distance between the pins30and44is about half an inch.

Two movable ring segments46,48extend from opposite ends of a common crank50. Each movable ring segment is J-shaped, having a straight segment52connected to the crank and a curved segment54. The end55(FIG. 3) of the curved segment has a conical recess57which receives the complementarily shaped tip20of the fixed segment.

The crank50(FIG. 2) has a throw formed by a straight segment58offset from the crank journals60. The crank is pivotally retained against the support plate by tabs62which are bent up out of the support plate and are curled around the journals60to form plain bearings. The leaf spring28bears up against the bottom of the throw58, tending to move the crank in a direction which opens the ring segments.

The nylon roller42engages the crank throw58from above. As the lever is depressed, the roller rolls along the crank throw, pushing the throw towards the support plate, thus closing the ring segments. When the lever strikes the support plate (FIG. 2), the roller is slightly past the center of the throw, and locks the throw down. The upward bias provided by the spring28holds the lever in this position until the lever is manually released.

FIG. 3shows the ring tips, greatly enlarged. The tip20of the stationary part18has a protrusion66of a diameter substantially less than that of the ring cross-section. The protrusion is shown with a conical base part68, but these details are only preferred. Whatever the exact shape of the protrusion, the tip55of the curved part of each movable ring segment46,48has a complementary recess70for receiving the protrusion66. A window72is provided to permit the protrusion66to enter into the recess at an angle, since the tips do not approach one another lengthwise, but rather at a substantial angle to the length of the stationary part. The window may have various shapes, but in any event it should be at least as large as the cross-section of the protrusion66, so that the protrusion can enter the recess without interference. The window may be made somewhat larger than that, to account for tolerances and bending of the components; however, too large a window would result in a less secure union between the mating tips.

While the protrusion has been described and shown on the stationary segment, with the complementary recess on the movable segment, it is possible to reverse the arrangement.FIG. 4shows this modification: here, the stationary straight part of the ring has a recess170in its tip155, and the movable curved part has a protrusion166adapted to seat in the recess. Note that the window172intersects the recess on only one side of the tip, i.e. on the inside of the ring, facing the center plane of the binder, but the idea is the same—to permit the protrusion to land smoothly in the recessed tip without interference.

Although the device illustrated is a two-ring binder, it should be understood that the invention is equally applicable to binders having more than two rings.

Since the invention is subject to modifications and variations, it is intended that the foregoing description and the accompanying drawings shall be interpreted as only illustrative of the invention defined by the following claims.