Looseleaf Binder

SPECIFICATION

The present patent application relates to looseleaf binders, and more particularly to lightweight, low cost ring binders.

Ring binders are customarily thought of as articles for sturdy, secure housing of documents. Although a wide variety of ring binder constructions are known, characteristically they incorporate a series of metal rings together with a mechanism for opening the rings to permit insertion of filler sheets, then closing the rings to securely engage the documents. The present invention relates to a ring binder which functions much in the traditional manner, yet is of an economical, easy-to-use design owing to its lightweight construction and novel ring mechanism.

It is known in the prior art, U.S. Pat. No. 2,71,768 Schade, to provide a looseleaf binder which has a series of rings or prongs secured to plates which are hinged together at a longitudinal center line, which plates may be manually pivoted at their hinge to open or close the binder. The looseleaf book of Schade, however, is of a heavy-duty construction, including, for example, metallic hinge plates 2, 3. Unlike the design of the present binder, the Schade plates are located at the back of the binder and in fact form the back panel of the binder. The prongs 8, 9 are of a semi-circular design, and are not profiled so as to snap into and out of engagement with each other but rather, overlap each other when closed.

It is a principal object of the invention to provide an economical lightweight ring binder.

Such ring binder should be easy to use. Its design should facilitate the opening and closing of the binder rings for insertion or removal of documents. The binder should also permit inserted sheets to lie flat, and inserted pages to be turned easily by the user.

In achieving the above and additional objects the invention provides a looseleaf binder which comprises a cover of flexible material which is folded to define front and back panels and a spine portion, said cover being foldable along a flexure axis at the back panel. The looseleaf binder further includes first and second hook assemblies which are secured to the back panel at either side of the flexure axis, each such assembly including a support member integral with a plurality of hooks all having notched engagement portions. Respective hooks of the first and second hook assemblies may be brought together and securely joined at their notched engagement portions to form binder rings for filler sheets, and the binder may be flexed along the flexure axis to separate the hooks and permit removal of filler sheets.

In a preferred, economical construction of the invention, the cover is comprised of a cardboard or pressboard material, and the first and second hook assemblies are comprised of a sturdy plastic material. The hook assemblies may be secured to the cover by inserting studs formed in the former assemblies through apertures in the cover's back panel, then subjecting the studs to heat or ultrasonic energy to weld the studs in place. Alternatively, the hook assemblies may be adhesively secured or riveted to the back cover.

Advantageously, the notched engagement portion of each of the hooks is defined by a hollow, and a boss which is complementary to the hollow, whereby respective hooks are engaged by press fitting the boss of one hook into the hollow of the mating hook. Each boss of a hook may include first and second engagement surfaces, wherein bosses of respective hooks slide along their respective first engagement surface during separation of hook assemblies, and along their second engagement surfaces during the joining of the hooks. The first engagement surface may provide a camming action which laterally separates the hooks when they are subjected to longitudinal separating forces. The second engagement surfaces may be oriented to gradually bring a pair of hooks into engagement.

The binder ring assemblies of the preferred binder construction incorporates interlocking hooks. In an alternative embodiment, the hooks have engagement portions which are configured to overlap but not interlock when the hooks are closed.

The above and additional aspects of the invention are illustrated in the following detailed description of the preferred embodiment, together with the drawings in which:

FIG. 1 is a perspective view of a three ring binder in accordance with the preferred embodiment of the invention, with its hooks closed;

FIG. 1A is a partial side view of the binder of FIG. 1 showing in its closed hooks;

FIG. 2 is a perspective view of the binder of FIG. 1 with its cover flexed to open the hooks;

FIG. 2A is a partial side view of the binder of FIG. 2 showing its opened hooks;

FIG. 3 is a top view of the binder of FIG. 1 with the cover flat and hooks closed;

FIG. 4 is a top view of the cover blank for the binder of FIG. 1;

FIG. 5 is a top view of the right hand hook assembly from FIG. 1;

FIG. 6 is a detail view from the top view of FIG. 5, showing the middle hook and surrounding features;

FIG. 7 is a left side view of the hook of FIG. 6; and

FIG. 8 is a right side view of the hook of FIG. 6;

FIG. 9 is a top view of a pair of closed hooks in accordance with an alternative embodiment of the invention;

FIG. 10 is a partial side view of a binder incorporating the hooks of FIG. 9, with the covers folded back; and

FIG. 11 is a partial side view of the binder of FIG. 10, with the covers closed.

FIGS. 1-8 illustrate a low cost three ring binder in accordance with a preferred embodiment of the invention. As seen in the perspective view of FIG. 1, the binder includes a cover 12 (here lying flat) and a ring mechanism consisting of left and right hand ring assemblies 20, 30 respectively. The ring assemblies 20, 30 each consist of a plate (21, 31) carrying a series of hooks (25, 35). The cover 12 is creased or hinged at 16 and 17 (See also FIG. 4) to define a front panel 13 and rear panel 15 as well as a spine portion 14. In addition, the cover is creased or hinged at 18 at a longitudinal center line of the ring assemblies 20, 30, both of which are secured to rear panel 15. Crease or hinge 18 permits the flexure of rear panel 15 to open and close the hooks 25a-c, 35a-c of the ring assemblies 20, 30. Note that since both of the ring assemblies 20 and 30 are located on the back cover 15, filler sheets will lie flat whether or not the front cover 13 is folded over the back cover 15. See also FIG. 1A, which shows that the hooks 25a, 35a form a generally inverted U-shaped configuration when they are closed. This configuration allows inserted sheets on either side of the cover to lie flat, and to be easily transferred from one set of hooks to the other.

FIG. 2 shows the flexure of the binder cover 12 to open the hooks 25a-c 35a-c. As seen in FIGS. 2, 2A, the cover is flexed at the crease or hinge 18 in order to cause the separation of the hooks.

The ring binder of the invention may be conveniently manufactured from low cost, lightweight materials. In one construction, the cover consisted of coated pressboard, and the ring assemblies 20, 30 were molded from a synthetic material such as high impact styrene. The cover blank 12 as seen in a top view of FIG. 4 was cut creased at 16, 17, and 18 and punched with apertures 11a-c, 19a-c which are used to secure the ring assemblies 20, 30. Ring assemblies 20, 30 were molded in identical configurations, i.e. the assemblies 20, 30 are indistinguishable when the hooks are aligned in the same direction. This feature lowers the cost of manufacture. When ring assemblies 20, 30 are mounted in the binders with the rings facing each other, the rings form a complementary (mating) profile. Ring assemblies 20, 30 each included a series of studs (22a-22c, 32a-32c) which are inserted in the cover blank apertures 11a-c, 19a-c and staked to the cover using heat, hot air or ultrasonic welding.

FIG. 4 shows the ring assembly 30 in a top view. As seen in FIGS. 1, 5, the plate 31 of ring assembly 30 includes a ledge 36 which supports the hooks 35a-35c. One edge of ring assembly 30 is indented in a profile complementary to that of the mating edge of ring assembly 20, including an indentation 37 and ridge 38. As seen in the detail view of FIG. 6, the hook 35b has a notched profile; as noted above this profile is complementary to that of a mating surface of hook 25b (see FIG. 3). As seen in FIGS. 6 and 8, hook 35b includes a notch 41 and a complementary boss 43. Boss 43 includes a sharply inclined engagement surface 45 as well as a more gradually inclined surface 48. When the user closes a pair of hooks, the surface 48 of each hook slides against a like surface of the opposite hook until the bosses of the hooks snap into the notches of these hooks. When a longitudinal separating force is exerted on the hook assemblies the sharply inclined surface 45 of each hook slides against a complementary surface of the opposite hook thereby laterally separating the respective hooks until they break free from one another. In one embodiment, the surface 48 forms an angle of 45 degrees with the opposite edge of hook 35b, while the surfaces 45, 48 form a mutual angle of slightly greater than 90 degrees.

This notched configuration permits the convenient opening and closing of the ring binder mechanism. When the hooks are closed the user may simply grasp the binder at both hook plates and flex the cover around the hinge or crease 18 to separate the hooks. The hooks may be snapped together easily by individually moving them toward each other.

FIGS. 7, 8 are side views of the left and right sides of the hook 35b of FIG. 6, showing in detail an advantageous configuration of a given hook. The hook includes a vertical portion 46 which retain filler sheets in a stack, and a curved portion 47. The left side of the hook is tapered at 38 (FIG. 7) while the right side has the notched configuration discussed above.

The ring construction of the preferred binder design discussed above incorporates interlocking hooks. In an alternative construction, shown in the top view of FIG. 9 and the side views of FIG. 10 (covers folded back) and 11 (covers closed), the hooks 55, 57 do not interlock, but include engagement portions 456, 58 which overlap when the rings are completely closed. The hook plates 51, 52 are secured to the cover using an adhesive.