Loose-leaf binder

Application filed December 16, 1930. Serial No. 502,636.

This invention relates to so-called ring binders for loose-leaf books. Such binders comprise separable rings, the segments of which (hereinafter called prongs) are cari'. ried upon movable, supports, usually in the form of flat plates, which have a rocking engagement at their inner or adjacent edges and are pressed toward each other, their relation being such that their movement between io the closed and open positions of the rings carries them past an intermediate or neutral nosition or plane so that the spring stress acts through the plates to hold the prongs apart when open and to hold them pressed 15 together when closed. Such plates are commonly called toggle plates, because they have an effective toggle action as they move in ehher direction past their neutral or mid position. The spring stress may be variousgo ly imparted but is most commonly applied by means of a resilient sheet-metal back plate, the outer edges of which are turned inwardly to form hooks or concave longitudinal flanges which embrace the outer edges, of 25 the prong plates and form, in effect, rocking pivots at their engagement therewith, in some instances, however, the resilience is provided within the material of the prong plates themselves, which is to be regarded as an so equivalent of the resilient back plate, in .

some cases, also, the structure is covere over n Fig. 3, the usual cover and the spring stress, supplement that of the back ^P1Such toggle prong plates as. heretofore made have had a rocking or knife-edge engagement with one another at their meeti _bor adjacent edges. The. present substitutes for this a varying rocking engagement by means of cam surf aces formed, upon or projecting from the meeting or adjacent edges of the plates. These cams are.so shaped that as the prongs open by the rising movement of the plates the rocking engagement or the cam faces presses the plates apart while ca-usinff their points of contact to desc.ena.re atively to the plates. The result is that thmr effective contact is brought much nearer to the medial line or neutral plane when the prongs are opened than when they, are closed. This has the, further effect of giving a very much lighter effective spring stress to hold the prongs open than that which acts when they are closed together to hold them closed. 55

It is common with ring binders of this type to provide some sort of opener (sometimes called a booster) for forcing the plates up at their adjoining edges to open the rings. Such opener is constructed to provide an ade- 60 quate leverage for overcoming the stiffness of the soring member by which the prongs are helddosed together. It is desirable that the springs stress be such as to hold the hooks together with considerable firmness in order 65 tojivoid any possibility of their separating and spilling out the leaves or sheets, as well as to make provision for the. gradual loss of spring stress which occurs in the course of time. ° With the ordinary binders the pro- 70 vision of such stiffness results in making it very difficult to press the prongs together to close the rings. The present invention has the effect of greatly diminishing the effective spring stress when the prongs are opened 75 while applying the maximum spring stress to hold the prongs closed. The preferable embodiment of the invention is that shown in the accompanying: drawings, wherein—

Figure 1 is a transverse section of the loose rin°· mechanism in open position, taken on ^J -. 3, the usual cover and the the cover being omitted from the drawings.

Fig. 2 is a longitudinal mid-section of one end nortion of the binding mechanism. .

Fig. 3 is a plan of the binding mechanism showing the prongs separated as in Fig. 1, a portion of the cover plate being broken away to better show the internal construction.

Fio·. 4 is a transverse section similar, to Fig. *1 but online 4—4 in Fig. 3, and with the prongs closed. J

Figs. 5 and 6 are transverse sections much _9aenlarged, showing, respectively, the closed and open positions of the prongs, these, views beinu in the plane of the line 5- 6 in Fig. 3·

Fm·. 7 is a fragmentary plan and edge view showing the cam on one of the prong plates. 100

Sa

1,857,291 ^Fj.8,· θ is a similar plan and edge view of a modified shape of cam.

According to the drawings, A, A are the usual prongs or half-rings, sometimes called hooks, and B, B are the prong plates or toggle plates which carry them. These, as stated, have- a rocking engagement at their approaching edges and turn upon substantially iixecl axes at their outer edges where, in the pre l ei. red construction, they are embraced between the inturned hook flanges or chanW= over and conceal the mechanism and is com- - -- - ’ ^y monly formed with outer hooked flanges d, d to embrace the flanges c, c. As stated, the resilient effect may reside in the back plate C or it may be in the cover plate D, or it may be partly in. each. Commonly, it is the back plate C which is mainly relied upon as the spring piate. In some instances in the art this back plate is so thick and stiff as to be substantially rigid, and the prong plates B, B are slotted or otherwise conformed so that the-resilient effect occurs within the material of these plates. These several constructions are regarded in the art as equivalents.

In the particular construction shown the prongs A, A are swaged or riveted into holes formed in the prong plates. The inner or rocking edges of the plates are kept in alignment by being formed with lips δ, & overlying one anther,, this, being a construction well understood in this art. The bearing en^aσθ.

..ment of the prong plates is accomplished^!! suitable intervals by means of cam portions Ji & which project slightly beyond the edges v P^{lates so as} i° bblfi the latter apart slightly (as shown in Fig. 3) except where

40. the cam portions E, E occur. These cam portions E, E are preferably bent down somewhat from the main level of the plate, as shown m Fig. 2 and in Fig. 7. Thev are formed in pairs so that those on the right and leJi-hand plates meet and engage each other with a-rocking or rolling contact. This contact, as the plates rock, may travel from one end of the mating cams to the other, or its travel may be in the direction of the thickness ot the plates,-this thickness being increased wnere the cam. portions are struck down, this will be best understood from an examination of Figs. 5 and 6, which show the preferable rocking engagement of the cam surtaces. In these figures the line x, x represents a plane intersecting the essential points of engagement of the outer edges of the plates with the hook flanges c, c on the -back plate (oi any equivalent points of engagement with eo whatever resilient means is employed). In

I ig. 5, where the prongs are closed together plates are clown, the cams engage at We Tomts which points are somewhat remotely below the middle of the line x, x. whereas in Fig, 6, where the prongs are separated to open the rings, the rocking engagement of the cams has brought their points of contact to the points y, y, which are much closer above the line x, x than the points w, w are beneath that line. As the To toggle action with respect to spring stress applied to the ends of the prongs is much more effective when the contact points (w, w) are remote from the neutral line x, x than w len they are, (as at y, y) close to that line, 75 it tollows that the springs stress is much ϋ . ,-------/ are opened apart.

m. action, as the prongs are separated by the rising of the middle portion of the plates, 80 the effective cam contact rolls downward while at the same time the contact surfaces passthrough the plane x, x between the outer pivotal edges of the plates so that when the plates reach their neutral position their outer 85 edges are materially separated, thereby forcing apart the flanges c, c of the spring plate; and as the plates pass this plane and move farther upward the rolling contact of the cams partially preserves this separation and oo maintains nearly the entire increased stress thus imparted to the resilient member. In this movement, of course, the effective contact points cross the medial line x, x so that the spring stress is reversed in its effective di- 85 rection so that in. the position shown in Fig.

, it is made effective to hold the prongs separatea By reason of the fact that the cams are struck downward from the plates it is qui„e practicable to carry the effective con- 100 tact points y,y entirely below the lower edges o± the places elsewhere, .as is apparent, this being a result not heretofore attained.

hus this invention in -its practical application in. effect redistributes the spring stress, 105 increasing its effect in the closed position of the prongs .and diminishing its effect in their opened position; the result is that the prongs form more perfect closed rings when the book is closed,-and when the prongs -are -separated to open the rings it -is much easier to -close them together -again than heretofore rimce -the invention makes it much more dihicult than heretofore to separate the prongs, it is important to provide a suitable opener .affording ample leverage for the purpose. buch -opener is constituted by a lever J ^al ’l°^Wn \^{n Fi}S^s- ^{2 and} 3, the long -arm of which overhangs -the end of the top plate D and the short arm / of which comes under the adjacent-edges of the prong.plates by which to pry them up and open the -prongs. Much· opener may -be -variously -constructed but is preferably of the construction shown and described m detail in my companion ap^{filed NGV}ember 26, 1930, Serial Nx>.

The shape of the cams may be greatly varied -without departing fromtlie invention, -fig. 8 is an example wherein tlie cam, in45

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12C

13C

1,857,291 derstood that the invention is not limited to this integral construction, as the cam faces might be on separate pieces united to the plates.