Patent Publication Number: US-6702501-B2

Title: Loose-leaf binder

Description:
This continuation-in-part of application Ser. No. 09/698,838, filed Oct. 27, 2000, now U.S. Pat. No. 6,371,678 which is a continuation of application Ser. No. 09/296,377, filed Apr. 22, 1999, now U.S. Pat. No. 6,196,749. 
    
    
     FIELD OF INVENTION 
     This invention relates to loose-leaf binders and analogous products such as loose-leaf personal organizers, loose-leaf flip charts, loose-leaf writing pads and loose-leaf photo albums. 
     BACKGROUND 
     Binders generally are comprised of two high-level assemblies, a “skeleton” and cover. The skeleton, as used herein, refers to the chassis of the binder, including the rings, spine and possible actuators, but excluding the cover. The spine, as used herein, refers to the elongated portion of the skeleton on which the rings are mounted; the spine excludes the rings, any transversely protruding elements disposed at the longitudinal ends of the skeleton such as actuation levers or proximate to the attachment points of rings such as springs wrapped around ring bases, and transversely protruding elements which are not fixed to rotate with the elongated portion such as a cover-attachment fastener wrapped about and rotatable about the elongated portion. 
     One object of loose-leaf binders, which is related to both the skeleton and the cover, is minimization of the “footprint” of the binder. The footprint of a binder is the area that is covered by any part of the binder when the binder is placed upon a generally flat surface. Minimizing a binder&#39;s footprint during use efficiently utilizes desk, table, or lap space. 
     A substitute product, the spiral notebook, specifically addresses this object by letting users flip the front cover and forward pages perfectly flat beneath the back cover and latter pages. However, spiral notebooks do not permit the easy addition or removal of pages. 
     Conventional loose-leaf binders have a very large footprint because, during use, the front cover is open 180 degrees relative to the back cover. This large footprint causes these binders to be cumbersome during use. Furthermore, if the front cover and forward loose-leaves are flipped behind the back cover and latter loose-leaves of a conventional binder, the forward and latter loose-leaves do not lie flat against the front and back covers, respectively. Large stress is exerted on some loose-leaves causing them to tear out of the binder and the airfoil shape of the stack of forward loose-leaves, front cover, back cover, and latter loose-leaves does not provide a flat writing surface. Furthermore in this case, writing on the topmost loose-leaf is difficult as the stack of loose-leaves bends and springs back under the shifting weight of a writing hand and wrist. 
     In the prior art, there have been attempts to minimize the footprints of loose-leaf binders during use while eliminating the problems mentioned above for conventional binders. However, each of these attempts has had some failing including: (1) sacrifice of a desired feature, (2) only partial achievement of this functionality, and (3) addition of undesirable characteristics. 
     The failings of known loose-leaf binders to minimize binder footprints are principally the result of (1) the large transverse cross-section dimensions of spines of known skeletons, (2) the methods employed to attach covers to skeletons, and (3) the design of the covers. 
     The first main cause of these failings, the large transverse cross-section dimensions of loose-leaf binder skeleton spines, has generally resulted from a common objective of skeletons, the ability to simultaneously open and close all rings of a skeleton via a simple actuation mechanism. SOCRA, which is used herein to describe these skeletons, is an acronym for Simultaneously Openable/Closeable Rings Actuation. 
     Conventional loose-leaf binders have SOCRA skeletons with spines having transverse cross-sections with major and minor dimensions wherein the large major dimension is built into the perimeter of the rings whereas the minor dimension is substantially radial to the center of the rings. Binder skeleton spines have traditionally had a transverse cross-section with a ratio of major to minor dimensions greater than two. 
     Conventional loose-leaf binders have a front cover attached to a middle cover which in turn is attached to a back cover. The SOCRA skeleton is rigidly fixed to the middle cover or back cover via rivets. 
     Exemplary dimensions of conventional loose-leaf binder covers in the market are as follows: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Front and Back Cover Thickness 
                 Middle cover Thickness 
               
               
                   
                   
               
             
            
               
                   
                 2 mm 
                 2 mm 
               
               
                   
                 3 mm 
                 4.5 mm   
               
               
                   
                 4 mm 
                 5 mm 
               
               
                   
                   
               
            
           
         
       
     
     Typical dimensions of conventional loose-leaf binder skeletons in the market are as follows: 
     
       
         
           
               
               
               
             
               
                   
               
               
                 Ring Outer Diameter 
                 Ring Prong Thickness 
                 Skeleton Spine Width 
               
               
                   
               
             
            
               
                 13.5 mm   
                 1 mm 
                 10 mm 
               
               
                 21 mm 
                 2 mm 
                 16 mm 
               
               
                 32 mm 
                 2.8 mm   
                 25 mm 
               
               
                 75 mm 
                 3.5 mm   
                 50 mm 
               
               
                   
               
            
           
         
       
     
     A ring outer diameter differs from its corresponding ring inner diameter by two ring prong thicknesses. Skeleton spine width is the major transverse cross-section dimension of a binder skeleton spine. The widths of skeleton spines are affected and constrained by the SOCRA mechanism employed and ring prong thickness. Note that as ring size increases, prong thickness increases to handle the stronger forces acting on the rings. Because ring prongs are commonly riveted into plates in conventional skeletons, as ring prongs increase in thickness, the skeleton spine width also must increase to secure the thicker prongs. The smallest conventional binders in the market which are small pocket binders have skeleton spine widths that are still 10 mm thick. Because of the thinness of cover segments and thickness of SOCRA skeleton spines in the prior art, the prior art generally teaches away from embedding of a SOCRA skeleton spine in a binder cover. 
     The large transverse cross-section of known SOCRA skeleton designs has led to the orientation of the transverse cross-section such that the major dimension is substantially radial to the center of the rings in an attempt to minimize the binder footprint. However, this orientation has made attachment to the cover more difficult which in turn has led to the use of loose-leaf front and back covers with no middle cover disposed therebetween. Such configuration exposes the rings and the ends of the loose-leaves leaving both less protected and makes the binder cumbersome to handle and less attractive. In such a known binder, the skeleton creates an awkward lump, thwarting the object of a flat writing surface, when positioned within a stack of loose-leaves or when positioned between the front cover and back cover after the front cover is flipped around against the back cover. U.S. Pat. No. 3,190,293 to Schneider, U.S. Pat. No. 4,904,103 to Im and U.S. Pat. No. 2,331,461 to Dawson are examples of such known binders. 
     Alternatively, to minimize binder footprints, some loose-leaf binders have independently-openable rings. In some of these loose-leaf binders, the back cover pivots about the thin skeleton spine and the front cover hangs loose-leaf on the rings, but there is no middle cover joining the front cover to the back cover. These designs make insertion and removal of loose-leaves tedious. Also, the exposed rings are unattractive and the loose-leaves are less protected. U.S. Pat. No. 659,860 to Schild and U.S. Pat. No. 2,268,431 to Slonneger are examples of such binders. 
     Yet another problem with known attempts to build a minimal-footprint binder are inadequate ring shapes having varying loose-leaf capacity when these binders are open 360 degrees versus when they are closed. This variation in capacity results from inclusion of the skeleton among the loose-leaves in one position but not in the other. U.S. Pat. No. 4,904,103 to Im is an example of such a binder. 
     SUMMARY OF INVENTION 
     Accordingly, this invention provides an improved binder that satisfies the object of providing a binder with a minimal footprint during operation while obviating the disadvantages of the prior art. The invention includes improvements to the binder skeleton, cover and attachment of the skeleton to the cover. 
     To minimize the binder footprint, the various embodiments of the invention described below contain at least one of the following elements as features: 
     (1) Skeleton with a minimal LSCPL (defined below). 
     (2) SOCRA skeleton. 
     (3) Cover designs that allow the front cover and back cover to fold in flat formations when open 360 degrees while simultaneously allowing the rings to rotate around an edge of the flatly-folded cover. 
     (4) Spine of skeleton axially disposed relative to rotation of rings and oppositely rotating back cover when the binder is open 360 degrees. 
     (5) Spine of skeleton embedded or partially embedded in cover in design and/or during operation of binder. 
     (6) Middle cover joining front cover to back cover. 
     (7) Attachment of the middle cover to back cover so that the covers do not interfere with rotation of the rings when the binder is opened 360 degrees. 
     (8) Slots or holes to eliminate interference of cover with skeleton rings as skeleton rings rotate through plane of back cover. 
     (9) Longest ring dimension is much larger than the LSCPL (defined below). 
     (10) Attachment of skeleton to cover in a way that allows the front cover to lie flat on the back cover while the binder is open 360 degrees. 
     (11) Rings hidden (not exposed) when binder is closed. 
     (12) Writing-support pads (described below). 
     (13) Stable, incremental rotation of rings about an edge of the flatly-folded cover without a strong bias to particular positions. 
     (14) Ring shapes with particular orientations to skeleton and cover to optimize or stabilize binder capacity. 
     The preferred embodiments have a spine. LSCPL is an acronym for the Longest Spine Cross-section Perimeter Line segment and refers to the longest line segment connecting two points on the perimeter of the transverse cross-section of the skeleton spine. For example, for a skeleton spine having a circular cross-section, the LSCPL is the circle&#39;s diameter; for an ellipse, the LSCPL is the major axis; for a square or rectangle, the LSCPL is a diagonal; for a triangle, the LSCPL is the longest side of the triangle. 
     The LSCPL dimension is important. When the binder cover is open 360 degrees, the binder cover is turned inside out such that at least a portion of the interior surfaces of the front and back covers face in opposite directions and the skeleton spine as well as a portion of the cover may be sandwiched between forward and latter loose-leaves. Preferably, the cover folds flat when open 360 degrees. The rings must be able to rotate while the cover is open 360 degrees. In the preferred embodiments, rotation of the rings necessitates that the spine rotate. If the LSCPL dimension is less than or equal to the thickness of the front and back covers, the spine can lie completely between the interior surface planes of the front and back cover throughout the complete range of the spine&#39;s rotation; in this case, the spine can remain flush with the front and back cover so that any potential lump caused by the spine while it is sandwiched between forward and latter loose-leaves is minimized or prevented so as to present a flatter top loose-leaf surface. Furthermore, the LSCPL dimension influences the desired thickness of a cover segment having a conduit in which the spine is rotatably disposed as a pivot of cover rotation; as the cover segment rotates about the spine, the conduit containing the spine must accommodate the LSCPL dimension. 
     Various features of each preferred embodiment cooperate to enable its loose-leaves above and below the back cover to lie flat and parallel when the cover is open 360 degrees whether none, one, many, or all of the loose-leaves are flipped below the back cover. 
     In the preferred embodiments, a SOCRA skeleton is rotatably disposed in a cover such that (1) the spine is a pivot about which the cover can rotate and (2) the spine is axially disposed relative to opposite rotations of the cover and rings. 
     Several embodiments of skeletons for use with the binder are disclosed for minimizing the LSCPL. For example, in one embodiment of a skeleton, the rings are attached via a space-saving weld or braze versus the space-demanding riveting of conventional binders. 
     Embedment of a skeleton in a cover segment without the segment becoming awkwardly thick and unattractive becomes feasible beginning with skeletons having LSCPL values of about 7-9 mm. Most preferably, the LSCPL of the skeleton is less than or equal 5 mm. 
     Preferably, the binder has a SOCRA skeleton with a synchronized switching element to open or close its rings simultaneously. The preferred synchronized switching element has a first connective element which connects to one set of ring segments and a second connective element which connects to a corresponding and opposing second set of ring segments. The synchronized switching element has a mechanism to enable the first connective element to move in relation to the second connective element so as to open or close the first ring segments relative to the second ring segments. 
     Means for attaching the front, middle and back cover segments are also disclosed. 
     OBJECTS AND ADVANTAGES 
     Accordingly, several objects or advantages of my invention contained in various embodiments described below are: 
     (a) to provide a binder which can minimize its footprint during use by flipping the front cover and any number of forward loose-leaves flatly beneath the back cover and latter loose-leaves and which lacks the limitations and failings of past attempts cited; 
     (b) to provide a binder which is reversible, so that either side may be used with equal advantages, the reversal being accomplished by opening the binder 360 degrees and then positioning it to access either the back of the exposed forward loose-leaf page or front of the exposed latter page, whereby either or both sides of a page may be written upon; 
     (c) to provide a binder which always presents a flat writing surface including when the front cover is opened 180 or 360 degrees relative to the back cover, and the whole surface of the current loose-leaf page is flat and can be used from edge to edge and top to bottom; 
     (d) to provide a binder whose front and back covers and optional writing-support pads may take the place of a desk, offering good support to write upon if the pad is rested in a lap or held in the hand; 
     (e) to provide an attractive binder with rings hidden when closed; 
     (f) to provide a binder affording superior protection to loose-leaves via a surrounding cover; 
     (g) to provide a binder that is easy to handle, conveniently packs in brief cases and book bags and stacks or stands well on a bookshelf; 
     (h) to provide a binder which reduces tearing stress on its loose-leaf pages when they are flipped beneath the back cover and latter pages; 
     (i) to provide a thin binder when closed by embedding the skeleton spine in the cover; 
     (j) To provide a binder with releasably retaining rings to bind loose-leaf pages permitting easy addition or removal of loose-leaf pages as desired; 
     (k) to provide a binder with the ability to simultaneously open or close all of the binder&#39;s rings by a skeleton mechanism to reduce the effort of adding or removing loose-leaf pages; 
     (l) to provide a binder with the smallest possible LSCPL skeleton value to eliminate or minimize any lump cause by the skeleton when the binder is open 360 degrees but where the skeleton fulfills its requirement to enable simultaneous opening and closing of all rings; 
     (m) to provide a binder with a skeleton which can accommodate various numbers and spacings of rings; 
     (n) to provide a binder with a skeleton that is spring urged to or can be locked in either of two stable states, an open position or closed position so its rings do not inadvertently open or close; 
     (o) to provide a skeleton with a ring shape that provides substantially constant capacity during operation when the skeleton may be rotated from its upright position; and 
     (p) to provide a binder that can be manufactured cheaply. 
     Further objects and advantages of my invention will become apparent from consideration of the drawings and ensuing description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a perspective view of an embodiment of the binder of the present invention with its front cover open approximately 120 degrees relative to the back cover in which the spine of the binder skeleton is rotatably disposed. 
     FIG. 1B is a perspective view of the binder of FIG. 1A in its closed position. 
     FIG. 1C is a perspective view of the binder of FIG. 1A with the front cover and forward loose-leaf pages flipped 180 degrees open relative to the back cover. 
     FIG. 1D is a perspective view of the binder of FIG. 1A with the front cover and forward loose-leaf pages flipped approximately 360 degrees to a fully open position flatly beneath the back cover and latter loose-leaf pages. 
     FIG. 1E is a cross-sectional view of the binder of FIG. 1D along line  1 E— 1 E in FIG.  1 D. 
     FIG. 1F is a sectional view of the binder of FIG. 1E after it has been flipped over 180 degrees to enable writing on the back side of a forward loose-leaf page. 
     FIG. 1G is a perspective view of the skeleton of FIG. 1A with the rings closed. 
     FIG. 1H is a perspective view of the skeleton of FIG. 1A with the rings open. 
     FIG. 1I is a perspective view of a component of the skeleton of the binder of FIG.  1 A. 
     FIG. 1J is a perspective view of additional components of the skeleton of the binder of FIG.  1 A. As is apparent from FIGS. 1A,  1 G- 1 H and  1 K- 1 L, the inner rod is preferably inserted into the hollow outer tube prior to the attachment of the ring halves to the inner rod during the manufacture of the spine. 
     FIG. 1K is a perspective view of the skeleton of the binder of FIG. 1A, when the rings are in the closed position, with a sectional portion displaying the construction of the synchronized switching element that is disposed within the spine and that simultaneously opens or closes the rings of the binder. 
     FIG. 1L is a perspective view of the skeleton of the binder of FIG. 1A, when the rings are in the open position, with a sectional portion displaying the construction of the synchronized switching element that is disposed within the spine and that simultaneously opens or closes the rings. 
     FIG. 2A is a perspective view of a second embodiment of the binder in the closed position where its front cover rides loose-leaf on its rings but is also connected to its middle cover by an attachment seam that is exterior to the binder rings. 
     FIG. 2B is a cross-sectional view of FIG. 2A indicated by the section lines  2 B— 2 B in FIG.  2 A. 
     FIG. 2C is a perspective view of the binder of FIG. 2A with loose-leaf pages removed and with the front cover flipped 180 degrees open relative to the back cover while the middle cover folds along an 180-degree-open crease. 
     FIG. 2D is the cross section of FIG. 2B where the front cover and forward loose-leaf pages have been flipped 180 degrees open relative to the back cover and the middle cover folds along a 180-degree-open crease. 
     FIG. 2E is the cross section of FIG. 2B where the front cover and forward loose-leaf pages have been flipped 360 degrees flatly beneath the back cover and latter loose-leaf pages and the middle cover folds along a 360-degree-open crease. 
     FIG. 3A is a perspective view of a third embodiment of the binder in the closed position where its front cover rides loose-leaf on its rings via cover-ring connection loops. 
     FIG. 3B is a cross-sectional view of FIG. 3A indicated by the section lines  3 B— 3 B in FIG.  3 A. 
     FIG. 3C is a perspective view of the binder of FIG. 3A with the front cover and forward loose-leaf pages flipped 180 degrees open relative to the back cover and with the middle cover folded along two 180-degree-open creases. 
     FIG. 3D is a cross-sectional view of FIG. 3C indicated by the section lines  3 D— 3 D in FIG.  3 C. 
     FIG. 3E is the cross-section of FIG. 3B where the front cover and forward loose-leaf pages have been flipped 360 degrees flatly beneath the back cover and latter loose-leaf pages and the middle cover folds along a 360-degree-open crease. 
     FIG. 4A is a perspective view of a fourth embodiment of the binder where part of the middle cover is interfaced to the front cover and is rotatable about the spine of the binder skeleton and the other part of the middle cover is interfaced to the back cover and is also rotatable about the spine of the binder skeleton. 
     FIG. 4B is a perspective view of the binder of FIG. 4A with the front cover flipped 180 degrees open relative to the back cover and with the middle cover stretched flush between them. 
     FIG. 4C is a perspective view of the binder of FIG. 4A with the front cover flipped 360 degrees open relative to the back cover while the segment of the middle cover that is interfaced to the front cover has been rotated roughly 180 degrees relative to the segment of the middle cover interfaced to the back cover. 
     FIG. 4D is a bottom view of the binder of FIG. 4C with loose-leaf pages added. 
     FIG. 5A is a perspective view of a fifth embodiment of the binder with its front and back covers interfaced to a middle cover with a middle beam that is rotatable about the spine of the skeleton. 
     FIG. 5B is a bottom view of the binder of FIG. 5A with loose-leaf pages added and where the front cover and forward loose-leaf pages have been flipped 360 degrees flatly beneath the back cover and latter loose-leaf pages. 
     FIG. 6A is a perspective view of a sixth embodiment of the binder with a loose-leaf front cover, no middle cover, and the back cover rotatable about the spine of the binder skeleton. 
     FIG. 6B is a perspective view of the back cover of the binder of FIG.  6 A. 
     FIG. 7A is a perspective view of a seventh embodiment of the binder having a quad-planar cover, composed of a back cover interfaced to a bi-planar middle cover that interfaces to a front cover, and having the spine of the binder skeleton rotatably disposed adjacent a free edge of the back cover. 
     FIG. 7B is a bottom view of the binder of FIG. 7A where forward loose-leaf pages have been flipped flatly beneath the cover segment containing the skeleton and beneath the latter loose-leaf pages and where the cover has been folded into a “Z” shape. 
     FIG. 8 is a perspective view of an eighth embodiment of the binder which is similar to the seventh embodiment but is also zipper-closable and the back cover is attached or detached via a hook-and-loop fastener. 
     FIG. 9 is a bottom view of a ninth embodiment of the binder which is similar to embodiment one but with a second middle cover segment that is interfaced to the front cover and that connects via hook-and-loop fastener to the back cover to fasten the binder shut. 
     FIG. 10 is a bottom view of a tenth embodiment of the binder and is similar to embodiment 9, but switches the position of permanent middle-cover-back-cover attachment with that of the hook-and-loop middle-cover-back-cover attachment position. 
     FIG. 11 is a bottom view of an eleventh embodiment of the binder with two opposing and enveloping front cover halves that fasten shut with a hook-and-loop fastener and where one front half is permanently connected to the back cover similar to Embodiment 1 while the other half is permanently interfaced to the back cover similar to Embodiment 10. 
     FIG. 12 is a perspective view of a twelfth embodiment of the binder having a quad-planar cover composed of a back cover which is rotatable about the spine of the skeleton and whose top edge is interfaced to the top edge of one of the planar segments of a bi-planar middle cover. 
     FIG. 13A is a perspective view of a thirteenth embodiment of the binder with the middle cover attached to the back cover in a manner similar to binder  1  but the back cover rides loose-leaf on the rings and the skeleton is not embedded in the cover. 
     FIG. 13B is a bottom view of the binder of FIG. 13A with the front cover flipped 360 degrees open relative to the back cover and with the front cover folded upon itself. 
     FIG. 14A is a perspective view of a fourteenth embodiment of the binder with the middle cover attached to the front and back covers in a manner similar to binder  2  but both the front and back covers ride loose-leaf on the rings and the skeleton is not embedded in the cover. 
     FIG. 14B is a bottom view of the binder of FIG. 14A with the front cover flipped 180 degrees open relative to the back cover and with the middle cover folded along a 180-degree-open crease. 
     FIG. 14C is a bottom view of the binder of FIG. 14A with the front cover flipped 360 degrees open relative to the back cover and with the middle cover folded along a 360-degree-open crease. 
     FIG. 15 is a bottom view of a fifteenth embodiment of the binder with the front cover open 180 degrees relative to the back cover, the skeleton embedded in the middle cover, the front and back covers ride loose-leaf on the rings, and the middle cover is connected to the front and back cover at attachment seams exterior to the rings. 
     FIG. 16A is a perspective view of a sixteenth embodiment of the binder which is similar to binder  1  but with openings instead of slots. 
     FIG. 17 is a perspective view of a seventeenth embodiment of the binder with the skeleton embedded near the top edge of the back cover so that loose-leaves hang from the top of the back cover. 
     FIG. 18A is a perspective view of an eighteenth embodiment of the binder where the back cover is rotatable about the spine of the skeleton, the planar segment of the bi-planar middle cover which interfaces with the back cover folds 180 degrees relative to the back cover and slot-holes that are half in the back cover and half in the middle cover are bisected by this fold and enable the rings to rotate counterclockwise without interfering with the back or middle cover. 
     FIG. 18B is a bottom view of the binder of FIG. 18A with the front cover flipped 180 degrees open relative to the back cover and with the addition of writing-support pads and loose-leaves. 
     FIG. 19A is a perspective view of a nineteenth embodiment of the binder which is similar to binder  18  with the addition of a folding slot cover. 
     FIG. 19B is a bottom view of the binder of FIG. 19A with the front cover in its closed position relative to the back cover and the folding slot cover in its stretched position and with the addition of writing-support pads and loose-leaves. 
     FIG. 19C is a bottom view of the binder of FIG. 19A with the front cover flipped 360 degrees open relative to the back cover and the folding slot cover in its folded position and with the addition of writing-support pads and loose-leaves. 
     FIG. 20A is a perspective view of a twentieth embodiment of the binder where the skeleton is embedded in a conduit and where the rings of the skeleton are looped through holes in the middle cover. 
     FIG. 20B is a bottom view of the binder of FIG. 20A with the front cover in its closed position relative to the back cover and with the addition of loose-leaves. 
     FIG. 20C is a bottom view of the binder of FIG. 20A with the front cover flipped 360 degrees open relative to the back cover and with the addition of loose-leaves. 
     FIG. 21A is a bottom view of a twenty-first embodiment of the binder in the closed position which is similar to the binder  20  but where the skeleton is embedded in a middle cover conduit of a constant cross-sectional shape. 
     FIG. 21B is a bottom view of the binder of FIG. 21A with the front cover flipped 360 degrees open relative to the back cover. 
     FIG. 22A is a bottom view of a twenty-second embodiment of the binder in a closed position which is similar to the binder  21 , but where the skeleton is not embedded in any conduit of the cover so that the middle cover rides loose-leaf on the rings. 
     FIG. 22B is a bottom view of the binder of FIG. 22A with the front cover flipped 360 degrees open relative to the back cover. 
     FIG. 23A is a bottom view of a twenty-third embodiment of the binder in a closed position having a flexible middle cover and a skeleton with a conventional arc-shaped spine which is firmly attached to the cover via a staple-thin rivet and is able to rotate via the flexibility of the middle cover. 
     FIG. 23B is a bottom view of the binder of FIG. 23A with its front cover open 360 degrees and with all its loose-leaves resting above the back cover. 
     FIG. 23C is a bottom view of the binder of FIG. 23A, but with its front cover, a writing-support pad, and one forward loose-leaf flipped beneath the back cover and latter loose-leaves. 
     FIG. 23D is a bottom view of the binder of FIG. 23A, but with its front cover, a writing-support pad, and half the loose-leaves flipped beneath the back cover and remaining half of the loose-leaves. 
     FIG. 23E is a bottom view of the binder of FIG. 23A, but with its front cover, a writing-support pad, and all but one forward loose-leaf flipped beneath the back cover and the one remaining latter loose-leaf. 
     FIG. 24A is a bottom view of a twenty-fourth embodiment of the binder in the closed position which is similar to the binder  23  but with a thinner, more flexible middle cover and a conventional round rivet that attaches its skeleton to its middle cover. 
     FIG. 24B is a bottom view of the binder of FIG. 24A, but with its front cover, a writing-support pad, and one forward loose-leaf flipped beneath the back cover and latter loose-leaves. 
     FIG. 24C is a bottom view of the binder of FIG. 24A, but with its front cover, a writing-support pad, and half the loose-leaves flipped beneath the back cover and remaining half of the loose-leaves. 
     FIG. 25A is a bottom view of a twenty-fifth embodiment of the binder in the closed position which has the same skeleton as the binders  23  and  24 , but whose skeleton rotates via a hinge joint in its back cover. 
     FIG. 25B is a bottom view of the binder of FIG. 25A, but with its front cover, a writing-support pad, and one forward loose-leaf flipped beneath the back cover and latter loose-leaves. 
     FIG. 26A is a perspective view of a second embodiment of a skeleton for use with the binder displaying the position of the skeleton actuator knob when the rings are in the open position. 
     FIG. 26B is a bottom, partial cross-sectional view of the skeleton of FIG. 26A displaying the construction of the synchronized switching element when the rings are in the closed position. 
     FIG. 26C is a front cross-sectional view of the skeleton of FIG. 26A displaying the construction of the synchronized switching element and actuator knob position when the rings are in the closed position. 
     FIG. 27A is a perspective view of a third embodiment of a skeleton for use with the binder having sectional portions displaying the construction of the synchronized switching element when the rings are in the closed position. 
     FIG. 27B is a perspective view of the skeleton of FIG. 27A with sectional portions displaying the construction of the synchronized switching element when the rings are in the open position. 
     FIG. 28A is a perspective view of a fourth embodiment of a skeleton for use with the binder having sectional portions displaying the construction of the synchronized switching element when the rings are in the closed position. 
     FIG. 28B is a perspective view of the skeleton of FIG. 28A with sectional portions displaying the construction of the synchronized switching element when the rings are in the open position. 
     FIG. 29A is a perspective view of a fifth embodiment of a skeleton for use with the binder that has its rings closed. 
     FIG. 29B is a bottom view of a ring component of the skeleton of  29 A. 
     FIG. 29C is a partial, cross-sectional view of FIG. 29A indicated by the section lines  29 C— 29 C in FIG.  29 A. 
     FIG. 30A is a bottom view of a first embodiment of a ring for use with the binder that has a partially elliptical shape with a linear top segment. 
     FIGS. 30B-30F are bottom views of the binder of FIG. 1 with its rings replaced with rings of FIG. 30A; FIGS. 30B-30F depict skeleton rotation and related cover positions as the front cover, writing-support pad, and varying numbers of forward loose-leaves are flipped beneath the back cover and varying numbers of latter loose-leaves. 
     FIG. 31A is a bottom view of a second embodiment of a ring for use with the binder that has a partially elliptical shape with linear top and bottom segments. 
     FIGS. 31B-31F are bottom views of the binder of FIG. 1 with its rings replaced with rings of FIG. 31A; FIGS. 31B-31F depict skeleton rotation and related cover positions as the front cover, writing-support pad, and varying numbers of forward loose-leaves are flipped beneath the back cover and varying number of latter loose-leaves. 
     FIG. 32A is a bottom view of a third embodiment of a ring for use with the binder that has a partially elliptical shape with three linear top segments. 
     FIGS. 32B-32F are bottom views of the binder of FIG. 1 with its rings replaced with rings of FIG. 32A; FIGS. 32B-32F depict skeleton rotation and related cover positions as the front cover, writing-support pad, and varying numbers of forward loose-leaves are flipped beneath the back cover and varying number of latter loose-leaves. 
     FIG. 33A is a bottom view of a fourth embodiment of a ring for use with the binder that has a partially elliptical shape with two linear top segments. 
     FIGS. 33B-33F are bottom views of the binder of FIG. 1 with its rings replaced with rings of FIG. 33A; FIGS. 33B-33F depict skeleton rotation and related cover positions as the front cover, writing-support pad, and varying numbers of forward loose-leaves are flipped beneath the back cover and varying number of latter loose-leaves. 
     FIG. 34 is the bottom view of another preferred embodiment of a ring component. 
     FIG. 35 is the bottom view of another preferred embodiment of a ring component. 
     FIG. 36A is a perspective view of a sixth preferred embodiment of a skeleton for use with the binder. 
     FIG. 36B is a perspective view of components of the skeleton of FIG.  36 A. 
     FIG. 36C is a perspective view of additional components of the skeleton of FIG.  36 A. 
     FIG. 36D is a perspective view of a wrap housing component of the skeleton of FIG.  36 A. 
     FIG. 36E is a bottom view of the skeleton of FIG. 36A with a sectional portion displaying the construction of the spreader component of the actuator (also known as the synchronized switching element) when the rings are in the closed position. 
     FIG. 36F is a bottom view of the skeleton of FIG. 36A when the rings are in the open position. 
     FIG. 37A is a perspective exploded view of a spreader component of the skeleton of FIG.  37 C. 
     FIG. 37B is a perspective view of torque lever components attached to the spine of the skeleton of FIG.  37 C. 
     FIG. 37C is a bottom view of another preferred embodiment of a skeleton for use with the binder with a sectional portion displaying the construction of the spreader component of the actuator when the rings are in the closed position. 
     FIG. 37D is a bottom view of the skeleton of FIG. 37C when the rings are in the open position. 
     FIG. 38A is a perspective view of a spreader component attached to torque levers, which are attached to the spine of the skeleton of FIG.  38 B. 
     FIG. 38B is a bottom view of another preferred embodiment of a skeleton for use with the binder with a sectional portion displaying the construction of the spreader component of the actuator when the rings are in the closed position. 
     FIG. 38C is a bottom view of the skeleton of FIG. 38B with a sectional portion displaying the construction of the spreader component of the actuator when the rings are in the open position. 
     FIG. 39A is a front view of a spreader component of the skeleton of FIG.  39 B. 
     FIG. 39B is a bottom view of another preferred embodiment of a skeleton for use with the binder when the rings are closed. 
     FIG. 39C is a bottom view of the skeleton of FIG. 39B when the rings are open. 
     FIG. 40A is a perspective view of another preferred embodiment of a skeleton for use with the binder with a sectional portion displaying part of the construction of the actuator when the rings are in the closed position. 
     FIG. 40B is a perspective view of the skeleton of FIG. 40A when the rings are open. 
     FIG. 41A is a perspective view of another preferred embodiment of a skeleton for use with the binder. 
     FIG. 41B is a perspective view of components of the skeleton of FIG.  41 A. 
     FIG. 41C is a perspective view of additional components of the skeleton of FIG.  41 A. 
     FIG. 41D is a perspective view of a wrap band component of the skeleton of FIG.  41 A. 
     FIG. 41E is a bottom view of the skeleton of FIG. 41A with a sectional portion displaying the construction of the spreader component of the actuator when the rings are in the closed position. 
     FIG. 41F is a bottom view of the skeleton of FIG. 41A with a sectional portion displaying the construction of the spreader component of the actuator when the rings are in the open position. 
     FIG. 42 is a bottom sectional view of another preferred embodiment of a spine for use with the binder with ring segments attached. 
     FIG. 43A is a bottom view of another preferred embodiment of a skeleton for use with the binder with a sectional portion displaying the construction of the actuator when the rings are in the closed position. 
     FIG. 43B is a bottom view of the skeleton of FIG. 43A with a sectional portion displaying the construction of the actuator when the rings are in the open position. 
     FIG. 44 is a bottom view of another preferred embodiment of a ring for use with the binder. 
     FIG. 45A is a perspective view of another preferred embodiment of a skeleton for use with the binder. 
     FIG. 45B is a bottom view of the binder of FIG. 1 with its skeleton replaced by the skeleton of FIG.  45 A and with its rings in the upright position. 
     FIG. 45C is a bottom view of the binder of FIG. 1 with its skeleton replaced by the skeleton of FIG.  45 A and with its rings rotated counterclockwise from the upright position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1A-1L 
     A first preferred embodiment of the binder  1  of the present invention is illustrated in FIGS. 1A-1D (perspective views of the binder  1  open 120 degrees, 0 degrees, 180 degrees, and 360 degrees, respectively), FIGS. 1E-1F (bottom views of the binder  1  open 360 degrees), and FIGS. 1G-1L (perspective views of the skeleton  50  of the binder  1 ). The binder  1  comprises cover  100  and skeleton  50  with optional loose-leaf writing-support pads  61 A and  61 B. 
     Cover  100  includes back cover  40 , middle cover  42 , and front cover  44 . Back cover  40  has interior surface  40 N and exterior surface  40 X and front cover  44  has interior surface  44 N and exterior surface  44 X. Back cover  40 , middle cover  42  and front cover  44  are typically made of cardboard, plastic, or other semi-rigid material that is optionally covered by a more flexible material such as vinyl or leather, but may be composed of any materials used to manufacture binder covers, loose-leaf flip-chart covers, loose-leaf personal organizer covers, or loose-leaf writing-pad covers. 
     Skeleton  50  comprises the spine  53  and a plurality of rings  46 . Rings  46  have ring segments  46 A and  46 B. Spine  53  includes tube  54  and inner rod  52 . Ring segments  46 B are disposed on tube  54  and ring segments  46 A, complementary with ring segments  46 B, are disposed on inner rod  52 . Spine  53  has a synchronized switching element  51  that simultaneously opens or simultaneously closes ring segments  46 A relative to ring segments  46 B. Ring segments  46 A and ring segments  46 B are disposed perpendicular to spine  53 . 
     Conduit  56  is defined by the back cover  40  and is proximate to and runs substantially parallel with the edge  40 A of back cover  40 . The spine  53  of the skeleton  50  is rotatably disposed within conduit  56 . Spine  53  is a pivot about which back cover  40  can rotate. Rings  46  are constrained to rotate with spine  53 . Because spine  53  is a pivot of back cover  40  and rings  46  rotate with spine  53 , spine  53  is axially disposed relative to opposite rotations of back cover  40  and rings  46 . Slots  58 A- 58 C are cut perpendicularly into the edge  40 A of back cover  40 . Back cover  40  defines paper margin supports  60 A- 60 D. The purpose of slots  58 A- 58 C which intersect conduit  56  and that of margin supports  60 A- 60 D will become apparent in the explanation of the operation of the binder  1 . 
     The rings  46  are aligned with their respective slots  58 A- 58 C so that at least a portion of each of the rings  46  is both received in and protrudes from one of the slots  58 A- 58 C and thereby allowing spine  53  to be rotatably disposed within the back cover  40 . Preferably, the tube  54  of spine  53  is constructed to have a relatively small cross-sectional dimension so that back cover  40  need not be unduly thick to define a conduit  56  large enough to receive the tube  54 . Preferably, the cross-sectional dimension of tube  54  ranges from about 4 mm to about 9 mm and more preferably from about 4 mm to 7 mm. 
     One edge of middle cover  42  merges into the plane of back cover  40  along seam  66  which is parallel to conduit  56 . Seam  66  can be located between conduit  56  and the far parallel edge  40 B of back cover  40  but is preferably located near conduit  56  without intersecting slots  58 A- 58 C. The other edge of middle cover  42  interfaces to an edge of front cover  44 . There need not be a distinct boundary distinguishing middle cover  42  and front cover  44 , but often there is one in the form of a seam, crease, or hinge. Optional pads  61 A and  61 B can be placed loose-leaf on rings  46  between which loose-leaves  72  may be added. The binder  1  has a loose-leaf stack space  79  which is the space available for occupation by loose-leaves  72  concurrently bound on rings  46  when the cover  100  is closed. 
     FIGS. 1G-1L show perspective and detailed cross-sectional views of skeleton  50  and its components. FIGS. 1G and 1H are perspective views of the skeleton  50  with rings  46  closed and open, respectively. In FIG. 1J, a plurality of ring segments  46 A are attached to rod  52  via a weld, braze, adhesive or other appropriate means; similarly, a corresponding number of ring segments  46 B are attached to tube  54  as shown in FIG.  1 I. When rod  52  is assembled within tube  54 , the spaced ring segments  46 A protrude through similarly spaced slots  55  defined by tube  54 . Preferably, the width of slots  55  approximates the cross-sectional diameter of ring segments  46 A, or guide mechanisms of some type—such as cylindrical grooves cut into the inner surface of tube  54  with complementary cylindrical flanges attached to rod  52 —are provided to constrain rod  52  from moving longitudinally relative to tube  54 . Slots  55  are cut long enough to enable tube  54  to concentrically rotate about rod  52  through a limited angle without interference from ring segments  46 A. Tube  54  can be rotated about rod  52  to open or close ring segments  46 A relative to ring segments  46 B. In this embodiment of a skeleton  50 , rod  52  and tube  54  serve as first and second connective elements, respectively, of synchronized switching element  51 . 
     FIGS. 1K and 1L show detailed views of the synchronized switch element  51  of spine  53  in the closed and open states, respectively. Preferably, the synchronized switch element  51  comprises tab  99 A of rod  52  which forms a sliding transmission linkage with slot  29 B which constrains cylinder  29  to rotate with rod  52 , but allows cylinder  29  to slide longitudinally towards and away from rod  52 . Cylindrical flanges  77  maintain the longitudinal center axis of rod  52  coincident with the longitudinal center axis of tube  54  to keep tab  99 A disposed within slot  29 B and ring segments  46 A aligned with ring segments  46 B. The smaller-diameter portion  29 D of cylinder  29  extends through the center of spring  31  and through stop  32 . The larger diameter portion  29 C of cylinder  29  is in constant opposing contact with spring  31  and the motion of portion  29 C is constrained to rotation and longitudinal movement by the inside surface of tube  54 . Semi-annular, dual-slotted ledge  28  is disposed within the inner diameter of tube  54 , and is preferably defined by or integrally formed as part of the tube  54 . Semi-annular ledge  28  defines open notches  28 A and  28 B divided by tooth  28 C. Tongue  29 A of cylinder  29  is kept in constant contact with ledge  28  by spring  31  as tongue  29 A slides over the tooth  28 C to and from the two notches  28 A and  28 B defined by ledge  28  during operation of the binder  1 . 
     There are four fundamental operations of the binder  1 , (i) opening or closing front cover  44  relative to back cover  40  to see and access the contents of the binder  1 ; (ii) writing on loose-leaf sheets; (iii) opening or closing rings  46  to insert or remove loose-leaf items such as paper and pocket folders; and (iv) handling and storage of the binder including carrying it in hand, standing it on a bookshelf, packing it in briefcases or bookbags, and stacking it horizontally. 
     The binder  1  is opened like a book from its closed position (FIG. 1B) by spreading its front cover  44  and back cover  40  apart (FIG. 1A) and, in so doing, usually rotating middle cover  42  relative to back cover  40  and front cover  44 . As shown in FIGS.  1 D- 1 F, the front cover  44  and forward loose-leaves  72 A can be disposed flatly beneath the back cover  40  of binder  1  and latter loose-leaves  72 B to minimize the footprint of the binder  1  during use. When front cover  44  and forward loose-leaves  72 A are pulled beyond  180  degrees relative to back cover  40 , skeleton  50  is able to rotate to accommodate this extended range of motion and thus prevents stress on loose-leaves  72  that could cause them to tear out of the rings  46 . The rotation of skeleton  50  also enables forward loose-leaves  72 A to lay flat against front cover  44  to provide flat writing surfaces when the binder  1  is open 360 degrees (FIGS.  1 E and  1 F). 
     Open slots  58 A- 58 C are defined by the back cover  40  which allow the rings  46  to (i) stand upright when the back cover  40  is closed and (ii) rotate along with the skeleton  50 . When the binder is open 180 degrees, skeleton  50  is able to rotate several degrees, typically 5-20 degrees, relative to its upright position because of slots  58 A- 58 C in back cover  40  but is stopped from rotating further by middle cover  42  which presses up against slots  58 A- 58 C when the middle cover  42  is supported by a flat surface. Since middle cover  42  is connected to back cover  40  between conduit  56  and the far parallel edge  40 B of back cover  40 , when front cover  44  is open 360 degrees relative to back cover  40 , middle cover  42  is pulled away from slots  58 A- 58 C and allows for maximum rotation of the rings  46  through the slots  58 A- 58 C. When cover  100  is folded open 360 degrees in a flat formation, a portion of each ring  46  is rotatable about near-ring edge  40 A, the pertinence of which is explained below. The angle of rotation of skeleton  50  from its upright position is determined by the relative number of forward loose-leaves  72 A flipped beneath back cover  40  to latter loose-leaves  72 B; i.e. the more loose-leaves  72  flipped beneath, the greater is the angle of rotation of skeleton  50  from its upright position. Other factors determining the angle that skeleton  50  rotates from its upright position are the diameter of rings  46 , the thickness of back cover  40 , and whether the binder is placed on a surface with the back cover  40  over front cover  44  (FIG. 1E) or vice versa (FIG.  1 F). 
     A portion of each ring  46  being rotatable about near-ring edge  40 A of the flatly-folded cover  100  serves two purposes: (1) it enables loose-leaves  72  to clear edge  40 A as they are moved from one side of the back cover  40  to the other side while bound on rings  46  and (2) it enables a first variable segment of each ring  46  to be located on the interior side of back cover  40  while a second variable segment of each ring  46  is concurrently located on the exterior side of back cover  40  which is necessary to enable loose-leaves  72  stacked flatly and bound on rings  46  above back cover  40  to be substantially parallel to loose-leaves  72  stacked flatly and bound on rings  46  below back cover  40 . For purpose (2) above to be possible, the inner diameter of each ring  46  must be greater than the thickness of the flat formation of cover  100  which equals the sum of the thicknesses of front cover  44  and back cover  40  which are placed together when cover  100  is open 360 degrees in the flat formation. The front cover  44  may be flexible enough or may have a fold or hinge such that it may be folded against itself while it is flipped back against back cover  40  in order to further reduce the footprint of the binder  1  (See FIG.  13 B). 
     FIG. 1C shows that users can write on the front or back of any loose-leaf  72  when the binder  1  is open 180 degrees. Likewise, when front cover  44  and forward loose-leaves  72 A are flipped back against back cover  40  and latter loose-leaves  72 B, the user can write on either the front side of the exposed latter loose-leaf  72 B or the back side of the exposed forward loose-leaf  72 A by positioning the binder as illustrated in FIGS. 1E and 1F, respectively. In this manner, the binder  1  of the present invention allows the user to write on the front or back of any loose-leaf  72  with the minimal binder footprint. 
     Whenever skeleton  50  is rotated from its upright position, the margin supports  60 A- 60 D provide support for writing so that almost the entire surface of loose-leaves  72  from left edge to right edge and from top to bottom can be written upon. Pads  61 A- 61 B which also assist in this writing-support effort are likely to be only semi-rigid and thus benefit from the added support of margin supports  60 A- 60 D in providing a flat, well-supported, writing surface. The support provided by both margin supports  60 A- 60 D and loose-leaf writing-support pads  61 A- 61 B help to prevent puncturing loose-leaves  72  during writing. 
     Rotatably disposing spine  53  of skeleton  50  within back cover  40 , outside of the loose-leaf stack space  79 , provides for a flat writing surface when front cover  44  and any forward loose-leaves  72 A are rotated either 180 degrees with respect to back cover  40  or approximately 360 degrees against the underside of back cover  40  and latter loose-leaves  72 B. Spine  53  must be able to rotate a with respect to the back cover  40  and be planar therewith in order to avoid the creation of uneven writing surfaces. 
     Skeleton  50  of FIG. 1A includes a synchronized switch element  51  to simultaneously open all rings  46  to a stable open state (FIGS. 1H and 1L) or to simultaneously close all rings  46  to a stable closed state (FIGS.  1 G and  1 K). Although, FIGS. 1K and 1L show some components of the synchronized switch element  51  to be disposed on one end of skeleton  50 , corresponding mirror-image components of the synchronized switching element  51  may be disposed on the opposite end of skeleton  50 , integrally formed with tab  99 B, to provide more balanced operation. Opening skeleton  50  involves separating the interfacing free ends of ring segments  46 A and ring segments  46 B which permits the reception or removal of the loose-leaf sheets (FIGS.  1 H and  1 L). Closing skeleton  50  involves adjoining the free ends of ring segments  46 A and ring segments  46 B to form completely closed rings  46  that secure the loose-leaf sheets within the binder (FIGS.  1 G and  1 K). 
     To open skeleton  50 , any two opposing ring segments  46 A and  46 B are pulled apart by the user&#39;s fingers. This action triggers the synchronized switch element  51  to open all of the rings  46  simultaneously. In operation, the rod  52  of synchronized switching element  51  is caused to rotate relative to tube  54  and is resisted by spring  31  when any of the two opposing ring segments  46 A and  46 B are pulled apart. As rod  52  rotates relative to tube  54 , cylinder  29  is constrained to rotate in sync by tab  99 A and slot  29 B but is also pushed longitudinally towards rod  52  by the spiral section or tooth  28 C of ledge  28  causing the compression of spring  31  between cylinder  29  and stop  32 . As rod  52  is rotated half between the closed and open positions, tongue  29 A of cylinder  29  is forced out of notch  28 A and slides over the tooth  28 C thus enabling spring  31  to expand and push tongue  29 A into notch  28 B thereby stopping the rotation of rod  52 . As shown in FIG. 1L, when tongue  29 A is disposed in notch  28 B, the rings  46  are in their open position and held therein by spring  31  biasing tongue  29 A into notch  28 B. 
     To close skeleton  50 , any two opposing ring segments  46 A and  46 B are pushed together by the user&#39;s fingers which again triggers the synchronized switching element  51  to close all of the rings  46  simultaneously. The action of pushing any two opposing ring segments  46 A and  46 B together causes rod  52  of synchronized switching element  51  to rotate relative to tube  54  against the resistance of spring  31 . As rod  52  rotates relative to tube  54 , cylinder  29  is constrained to rotate in sync by tab  99 A and slot  29 B but is also pushed longitudinally or linearly towards rod  52  by tooth  28 C of annular ledge  28  causing the compression of spring  31  between cylinder  29  and stop  32 . As rod  52  is rotated half between the open and closed positions, tongue  29 A of cylinder  29  is forced out of notch  28 B and slides over tooth  28 C thus enabling spring  31  to expand and push tongue  29 A into notch  28 A thereby stopping the rotation of rod  52 . As shown in FIG. 1K, when tongue  29 A is disposed in notch  28 A, the rings are in their closed position and held therein by spring  31  biasing tongue  29 A into notch  28 A. 
     The binder cover  100 , when closed, almost completely encompasses loose-leaves  72  and skeleton  50  including rings  46  and thus resembles a book. The encompassing is such that each of 270 rays emanating from the center of one of the rings  46  and spaced at consecutive 1-degree angular increments and intersecting the perimeter of that ring  46  subsequently intersects the cover  100  when the cover  100  is closed. Consequently, it is easier to stand the binder  1  on a shelf, it is less awkward to carry, it is easier to store in containers such as book shelves, brief cases, and back packs, it is more attractive, and it provides more protection to the loose-leaf pages  72  than a binder with a less enveloping cover, such as those with exposed rings. 
     FIGS. 2A-2E 
     FIGS. 2A-2E show perspective and sectional views of another preferred embodiment of a binder  2  of the present invention. The binder  2  comprises cover  200  and skeleton  50 . Cover  200  includes front cover  144 , middle cover  142 , and back cover  40 . The binder  2  comprises the same back cover  40  and skeleton  50  as the binder  1  shown in FIGS. 1A-1L, but incorporates a different middle cover  142  and front cover  144 . Front cover  144  defines holes  74 A for receiving rings  46  thereby enabling front cover  144  to be releasably bound by rings  46  in the same manner that loose-leaves  72  are releasably bound by the rings  46 . Front cover  144  is connected to middle cover  142  via seam  166  which is disposed between holes  74 A and the far parallel edge  144 A of front cover  144 . The preferred location of seam  166  is nearer holes  74 A than the far edge  144 A of front cover  144 . Middle cover  142  has crease  80  and crease  82  and connects to back cover  40  as in the binder  1  as shown in FIGS. 1A-1C. 
     Because front cover  144  rides loose-leaf on rings  46 , rings  46  constrain the motion of front cover  144 . When the binder  2  is opened 180 degrees and placed on a surface or when the binder  2  is opened 360 degrees, rings  46  constrain front cover  144  which in turn forces middle cover  142  to fold upon itself. To encourage smooth folding with a minimal resulting lump, creases  80  and  82  are preferably formed in middle cover  142 . When the binder  2  is opened 180 degrees, middle cover  142  tends to fold along crease  80  and when the binder  2  is opened 360 degrees, middle cover  142  tends to fold along crease  82 . For illustrative purposes, middle cover  142  has noticeable thickness in FIGS. 2A-2E; in practice middle cover  142  can be paper-thin to minimize any lump it creates when the binder  2  is open 360 degrees. FIG. 2E shows the minimal resulting footprint of the binder  2  provided when cover  200  is open 360 degrees in a flat formation between forward loose-leaves  72 A and latter loose-leaves  72 B. For purpose (2) recited earlier in the description of the binder  1  shown in FIGS. 1A-1F, the inner diameter of rings  46  is substantially greater than the thickness of the flat formation of cover  200  which equals the sum of the thickness of back cover  40  plus the thickness of front cover  144  plus twice the thickness of middle cover  142 . 
     Another advantage of the binder  2  of the present invention is more compact storage due to less wasted interior space of the binder. Since front cover  144  rests flatly on loose-leaves  72  when the binder is closed (FIGS.  2 A and  2 B), there is no air pocket between the top loose-leaf  72  and front cover  144 . This advantage is significant when considering the limited space of a briefcase or bookbag. The binder  2  of the present invention provides the advantages of an enveloping cover for the rings  46  while creating only a minimal footprint when opened approximately 180 degrees or 360 degrees. 
     FIGS. 3A-3E 
     FIGS. 3A-3E show perspective and sectional views of yet another preferred embodiment of a binder  3  of the present invention. The binder  3  comprises cover  300  and skeleton  50 . Cover  300  includes front cover  244 , middle cover  242 , and back cover  40 . The binder  3  comprises the same back cover  40  and skeleton  50  as the binder  1  shown in FIGS. 1A-1L, but incorporates a different middle cover  242  and a different front cover  244 . Front cover  244  has loops  84  for receiving rings  46  so that it can be releasably bound by the rings  46 . Front cover  244  is connected to middle cover  242  in the same manner as the front cover  44  is connected to middle cover  42  in binder  1  as shown in FIGS. 1A-1C. Creases  180 A,  180 B and  182  are preferably formed in middle cover  242  which is connected to back cover  40  in the same manner as the middle cover  42  of binder  1  is connected to back cover  40  as shown in FIGS. 1A-1C. 
     Because front cover  244  of the binder  3  of the present invention rides loose-leaf on rings  46 , rings  46  constrain the motion of front cover  244 . When the binder  3  is opened 180 degrees and placed on a surface or when the binder  3  is opened 360 degrees, rings  46  constrain front cover  244  which in turn forces middle cover  242  to fold upon itself as shown in FIGS. 3D-3E. To encourage smooth folding with a minimal resulting lump, creases  180 A,  180 B and  182  are preferably formed in middle cover  242 . When the binder  3  is opened 180 degrees, middle cover  242  tends to fold along crease  180 A and crease  180 B as shown in FIG. 3D, but when the binder  3  is opened 360 degrees, middle cover  242  tends to fold along crease  182  as shown in FIG.  3 E. FIG. 3E shows the minimal resulting footprint of binder  3  of the present invention when opened about 360 degrees. Because front cover  244  of the binder  3  rests on rings  46 , the binder provides the familiar, slightly triangular look-and-feel of known ring binders when closed, and also provides the advantages of an enveloping cover previously discussed with respect to the binder  1  of the present invention. 
     FIGS. 4A-4D 
     FIGS. 4A-4D show perspective and bottom views of an additional embodiment of a binder  4  of the present invention. The binder  4  comprises the same skeleton  50  as the binder  1  shown in FIGS. 1A-1L and cover  400 . Cover  400  includes back cover  140 , middle cover  342 , and front cover  344 . Middle cover  342  has two small middle cover portions  342 A separated by a large middle cover portion  342 B which are all pivotable about spine  53  of skeleton  50 . Middle cover  342  has conduit  56 B to hold spine  53  of skeleton  50 . Middle cover portion  342 B pivots about spine  53  in a manner similar to how back cover  40  pivots about spine  53  in the binder  1  shown in FIGS. 1A-1C. Slots  158 A- 158 C and margin supports  160 A- 160 D are defined by middle cover portion  342 B. 
     When the binder  4  is open 360 degrees (FIGS.  4 C and  4 D), skeleton  50  has been rotated within middle cover portion  342 B to allow for the extended range of motion similar to how skeleton  50  can be rotated within back cover  40  of the binder  1 . In both the 180-degree and 360-degree open positions, middle cover portion  342 B behaves like an extension of back cover  140 ; the two provide one mostly planar surface to support loose-leaves  72 . This is possible because middle cover portion  342 B is the same thickness as back cover  140  except near the constricted neck or crease  140 A where middle cover portion  342 B and back cover  140  are connected or integrally formed (FIG.  4 B). The addition of writing-support pads  61 A and  61 B (see FIGS. 1E and 1F) to the binder  4  could cover any crevices that might lead to puncturing loose-leaves  72  during the writing process. 
     Middle cover portions  342 A are connected to or integrally formed with an edge  344 A of front cover  344  with creases  344 B disposed therebetween. Middle cover portions  342 A pivot about respective ends of skeleton  50 . Middle cover portions  342 A do not interfere with the rotation of skeleton  50 . When the binder  4  is open 360 degrees, middle cover portions  342 A curve around middle cover  342 B to enable front cover  344  to lie flat against back cover  140  as shown in FIG.  4 D. 
     FIGS. 5A-5B 
     FIGS. 5A and 5B show perspective and bottom views of yet an additional embodiment of a binder  5  of the present invention. The binder  5  comprises the same skeleton  50  as the binder  1  and cover  500 . Cover  500  includes back cover  1440 , middle cover  442 , and front cover  1044 . Middle cover  442  of the binder  5  comprises a base  442 A, a beam  86  disposed on base  442 A and creases  442 B and  1 D  442 C disposed at the respective junctures of the beam  86  with base  442 A. The spine  53  of skeleton  50  is rotatably disposed in conduit  56 A. Slots  258 A- 258 C are defined by middle cover  442 . Margin supports  260 A- 260 D are defined by beam  86  of middle cover  442 . The base  442  A of middle cover  442  and front cover  1044  are joined together at crease or fold  1044 A. The base  442 A and back cover  1440  are joined at crease or fold  1440 A. 
     Although skeleton  50  can rotate relative to middle cover  442 , only limited rotation is needed, the amount of rotation needed being influenced by the amount of loose-leaves  72  on one side of beam  86  of middle cover  442  compared with the other side. When the binder  5  is open 360 degrees (FIG.  5 B), the skeleton  50  need not rotate substantially because of the manner in which the base  442 A folds upon itself at creases  442 B and  442 C to enable front cover  1044  to lie flat against back cover  1440 . To enable middle cover  442 , back cover  1440  and front cover  1044  to form two parallel planar surfaces when the binder is open 360 degrees, the base  442 A of middle cover  442  as well as back cover  1440  and front cover  1044  are half as thick as beam  86  of middle cover  442 . Optional writing-support pads  61 A and  61 B cover crevices associated with folds  442 B and  442 C and slots  258 A- 258 C. When cover  500  is folded flatly open 360 degrees, beam  86  coincides with the near-ring edge of flatly-folded cover  500  and a portion of each ring  46  is rotatable about this edge. 
     FIGS. 6A-6B 
     FIG. 6A shows a perspective view of another embodiment of a binder  6  of the present invention comprising cover  600  and skeleton  50 . FIG. 6B shows a perspective view of back cover  240 . Cover  600  includes back cover  240  and front cover  444 . The binder  6  of the present invention is similar to the binder  2  shown in FIGS. 2A-2E except that the binder  6  has no enveloping middle cover  42 . Spine  53  of skeleton  50  is rotatably disposed in conduit  56  defined by back cover  240  such that spine  53  is a pivot of back cover  240 . Like the front cover  144  of the binder  2  shown in FIGS. 2A-2E, front cover  444  of the binder  6  of the present invention defines holes  74 A for receiving rings  46  thereby enabling front cover  444  to be releasably bound by the rings  46 . Since there is no middle cover, the binder  6  of the present invention is more economical to manufacture and easier to open and close than similar binders having middle covers. 
     FIGS. 7A-7B 
     FIGS. 7A and 7B are perspective and bottom views of yet an additional preferred embodiment of a binder  7  of the present invention. The binder  7  comprises cover  700  and skeleton  50 . Cover  700  includes back cover  340 , middle cover  542 , and front cover  44 . The binder  7  is a variation of the binder  1  of the present invention having middle cover  542 , which has been enlarged and is attached or integrally formed with the far edge  340 B of back cover  340 . Middle cover  542  is a bi-planar middle cover having middle cover portion  542 A and middle cover portion  542 B. The binder  7  of the present invention opens to 180 degrees similar to the binder  1  shown in FIGS. 1A-1F, but opens differently to the 360 degree position. FIG. 7B shows the binder  7  cover folded in a “Z” shape when opened 360 degrees and forward loose-leaves  72 A are sandwiched between back cover  340  and middle cover portion  542 B. When cover  700  is open 360 degrees, only back cover  340  of cover  700  is in flat formation between forward loose-leaves  72 A and latter loose-leaves  72 B. The inner diameter of rings  46  is substantially greater than the thickness of the flat formation of back cover  340  for a purpose (2) recited earlier in the description of the binder  1 . 
     FIG. 8 
     FIG. 8 is a perspective view of yet another preferred embodiment of a binder  8  of the present invention. The binder  8  comprises cover  800  and skeleton  50 . Cover  800  includes back cover  440 , middle cover  642 , front cover  544 , and zipper  88 . The binder  8  is similar to the binder  7  shown in FIGS. 7A-7B since back cover  440  connects to middle cover portion  642 B of the binder  8  much like back cover  340  connects to middle cover portion  542 B of the binder  7 . The binder  8 , however, also comprises a zipper  88  for securely enclosing back cover  440 , skeleton  50  and loose-leaves  72  (not shown) for improved storage and handling capability. Middle cover  642  has portions  642 A and  642 B. In addition, back cover  440  is releasably attached to middle cover portion  642 B via a loop  91  and hook  90  fastener. Hooks  90  are disposed on the back cover interior surface  440 N and loops  91  are disposed on a flap  78  attached to middle cover  642 B. 
     Since zipper  88  can become an encumbrance during usage, back cover  440  can be detached from the other cover sections of the binder. Spine  53  of skeleton  50  is disposed in conduit  56  of back cover  440 . When the back cover  440  is detached from middle cover portion  642 B, the binder  8  then resembles the binder  6  and can be used in a similar fashion bearing a minimal footprint when the forward loose-leaves  72 A are flipped back against back cover  440 . If zipper  88  is not an inconvenience, back cover  440  can be left attached to middle cover  642 , and forward loose-leaves  72 A can be flipped beneath back cover  440  by sandwiching them between back cover  440  and middle cover portion  642 B. 
     FIG. 9 
     FIG. 9 shows a bottom view of an additional preferred embodiment of a binder  9  of the present invention. The binder  9  comprises cover  900  and skeleton  50 . Cover  900  includes back cover  540 , middle covers  742 A and  742 B, and front cover  644 . The binder  9  is similar to the binder  1  shown in FIGS. 1A-1F but also comprises a dual-purpose fastener comprising loops  190  and hooks  192 A and  192 B and an extra middle cover  742 B. Middle cover  742 A and middle cover  742 B are disposed on opposite sides of the binder  9 . Crease or hinge  742 C is disposed between middle cover  742 A and front cover  644  while crease or hinge  742 D is disposed between front cover  644  and middle cover  742 B. Several rows of hooks  190  are disposed on back cover  540  which cooperate with the rows of loops  192 A and  192 B disposed on middle cover  742 B and front cover  644 , respectively. The dual purpose fastener is composed of hooks  190  and alternative attachment positions at loops  192 A or loops  192 B. 
     When the binder  9  is closed, hooks  190  fasten to loops  192 A. When the binder  9  is opened 360 degrees as substantially shown in broken lines in FIG. 9, front cover  644  is folded upon itself at crease  81  and hooks  190  fasten to loops  192 B to hold front cover  644  securely in place against back cover  540 . The addition of middle cover  742 B lets the binder  9  enclose rings  46  and inserted loose-leaves  72  on four sides when the binder  9  is closed and thus provides improved storage and handling. When the binder  9  is opened 360 degrees in a flat formation, front cover  644 , middle cover  742 A, and middle cover  742 B are disposed beneath the wide portion of back cover  540 , as divided by conduit  56 , to avoid interfering with the rotation of rings  46  and to minimize the footprint of the binder  9 . For purpose (2) recited earlier in the description of the binder  1  shown in FIGS. 1A-1F, the inner diameter of rings  46  is substantially greater than the thickness of the flat formation of cover  900  which equals the sum of the thickness of back cover  540  plus twice the thickness of front cover  644 . 
     FIG. 10 
     FIG. 10 shows a bottom view of yet another preferred embodiment of a binder  10  of the present invention. The binder  10  comprises cover  1000  and skeleton  50 . Cover  1000  includes back cover  640 , middle covers  842 A and  842 B, and front cover  744 . The binder  10  is similar to the binder  9  of FIG. 9 in that the binder  10  comprises a dual purpose fastener comprising hooks  290  and loops  292 A and  292 B and an extra middle cover segment  842 B. Crease or hinge  842 C is disposed between middle cover  842 A and front cover  744  while crease or hinge  842 D is disposed between front cover  744  and middle cover  842 B. Whereas middle cover  742 A, front cover  644 , and middle cover  742 B are rotated clockwise to a position underneath back cover  540  in the binder  9  in FIG. 9, middle cover  842 B, front cover  744 , and middle cover  842 A of the binder  10  are rotated counterclockwise to a position underneath back cover  640 . Thus, the respective front covers  644  and  744  of the binders  9  and  10  open in opposite directions. In addition, the binder  10 , like the binder  9 , encloses rings  46  and inserted loose-leaves on four sides when closed and uses dual-purpose hook-and-loop fasteners. 
     The fastener of the binder  10  comprises rows of hooks  290  disposed on back cover  640  and alternative attachment positions comprising rows of loops  292 A and  292 B disposed on middle cover  842 A and front cover  744 , respectively. When the binder  10  is closed, the rows of hooks  290  fasten to the rows of loops  292 A. When the binder  10  is opened 360 degrees as substantially shown in broken lines in FIG. 10, front cover  744  is folded upon itself at crease  181  and the rows of hooks  290  fasten to the rows of loops  292 B to hold front cover  744  securely in place against back cover  640 . 
     FIG. 11 
     FIG. 11 shows a bottom view of another preferred embodiment of a binder  11  of the present invention. The binder  11  comprises cover  1100  and skeleton  50 . Cover  1100  includes back cover  740 , middle covers  942 A and  942 B, and front cover  844 . Front cover  844  has releasably connecting portions  844 A and  844  B. The binder  11  shares similarities with the binder  9  of FIG.  9  and the binder  10  of FIG.  10 . The binder  11  of the present invention comprises a front-middle cover segment made up of front cover portion  844 A and middle cover  942 A that is permanently attached to back cover  740  near conduit  56 . The binder  11  also comprises a front-middle cover segment made up of front cover portion  844 B and middle cover  942 B that is permanently attached to the back cover  740 . Crease or hinge  942 C is disposed between middle cover  942 A and front cover portion  844 A while crease or hinge  942 D is disposed between front cover portion  844 B and middle cover  942 B. The two front-middle cover segments fasten together above back cover  740  when the binder  11  is closed or below back cover  740  when the binder  11  is open. The dual purpose hook-and-loop fastener of binder  11  comprises rows of hooks  390  and alternative attachment positions comprising rows of loops  392 A and  392 B. 
     When the binder  11  is closed, hooks  390  fasten to loops  392 A. When the binder  11  is opened 360 degrees as substantially shown in the broken lines of FIG. 11, front cover portion  844 B is folded upon front cover portion  844 A and hooks  390  fasten to loops  392 B to hold front cover portion  844 A and front cover portion  844 B securely in place against back cover  740 . Like the binder  9  of FIG.  9  and the binder  10  of FIG. 10, the binder  11  of the present invention encloses rings  46  and inserted loose-leaves  72  on four sides when closed and when open 360 degrees, middle cover  942 A, middle cover  942 B, front cover portion  844 A, and front cover portion  844 B are disposed beneath the wide portion of back cover  740 , as divided by conduit  56 , to avoid interfering with the rotation of rings  46 . 
     FIG. 12 
     FIG. 12 shows a perspective view of yet an additional embodiment of a binder  12  of the present invention. The binder  12  comprises cover  1200  and skeleton  50 . Cover  1200  includes back cover  840 , middle cover  1042 , and front cover  44 . The binder  12  differs from most of the binders presented thus far in how middle cover  1042 , having portions  1042 A and  1042 B, avoids interfering with the rotation of rings  46  of skeleton  50  when forward loose-leaves  72 A are flipped beneath back cover  840  and latter loose-leaves  72 B. The middle cover portion  1042 B is connected to the back cover  840  with a hinge joint or fold  840 A. As shown in FIG. 12, middle cover portion  1042 A is disposed between middle cover portion  1042 B and front cover  44 . 
     When loose-leaves  72  are to be flipped beneath back cover  840 , back cover  840  is pivoted up about fold  840 A which is preferably expandable to accommodate a large volume of loose-leaves  72  flipped underneath the back cover  840 . Forward loose-leaves  72 A are then flipped 360 degrees around back cover  840  causing the rotation of rings  46 . Back cover  840  is subsequently pivoted back toward its original position which sandwiches the forward loose-leaves  72 A between back cover  840  and middle cover portion  1042 B. To write on the reverse side of a loose-leaf, back cover  840  is flipped from the front side of middle cover portion  1042 B up against the back side thereof so that the reverse side of the desired loose-leaf is exposed. To minimize the footprint of the binder, front cover  44  can be folded against one side of middle cover portion  1042 B while back cover  840  is folded against the other side of middle cover portion  1042 B. Alternatively, front cover  44  can be sandwiched between middle cover portion  1042 B and back cover  840 . 
     FIGS. 13A-13B 
     FIGS. 13A and 13B are perspective and bottom views, respectively, of an additional embodiment of a binder  13  of the present invention. The binder  13  comprises cover  1300  and skeleton  50 . Cover  1300  includes front cover  44 , middle cover  42 , and back cover  940 . Like the binder  1  of FIG. 1A, middle cover  42  of the binder  13  attaches to back cover  940  at seam  66 . Back cover  940  has holes  74 B to enable it to be releasably attached to rings  46  and has open conduit  156  which intersects holes  74 B. Spine  53  of skeleton  50  is not disposed within back cover  940 . However, when the binder  13  is open 360 degrees as shown in FIG. 13B, the open conduit  156  defined by back cover  940  receives tube  54  of spine  53  to minimize or eliminate the lump caused by spine  53  so that back cover  940  can lie flat. Because back cover  940  hangs in a loose-leaf manner on rings  46  via holes  74 B, spine  53  and rings  46  are able to rotate relative to back cover  940  as needed when the binder  13  is open 360 degrees. Front cover  44  is preferably flexible enough to fold against itself to minimize the binder&#39;s footprint when open 360 degrees. When the binder  13  is closed, skeleton  50  is surrounded by back cover  940 , middle cover  42 , and front cover  44  so that rings  46  are not exposed thus making the binder  13  more attractive and easy to handle. 
     FIGS. 14A-14C 
     FIGS. 14A-14C are perspective and bottom views of a further preferred embodiment of a binder  14  of the present invention. The binder  14  comprises cover  1400  and skeleton  50 . Cover  1400  includes middle cover  142 , back cover  940 , and front cover  944 . Like the binder  2  of FIGS. 2A-2E, middle cover  142  of the binder  14  attaches to back cover  940  and front cover  944  at seams  66  and  166 , respectively. Front cover  944  has holes  74 A to enable it to be releasably attached to rings  46  and has open conduit  256  which intersects holes  74 A. Likewise, back cover  940  has holes  74 B to enable it to be releasably attached to rings  46  and has open conduit  156  which intersects holes  74 B. Spine  53  of skeleton  50  is not disposed within back cover  940 . When the binder  14  is open 360 degrees as shown in FIG. 14C, middle cover  142  folds flat along crease  82  and the open conduits  156  and  256  defined by the back cover  940  and front cover  944 , respectively, receive tube  54  of spine  53  to minimize or eliminate the lump caused by spine  53  so that back cover  940  can lie flat relative to front cover  944 . When the binder  14  is open 180 degrees as shown in FIG. 14B, middle cover  142  tends to fold flat along crease  80 . When the binder  14  is open 360 degrees, spine  53  and rings  46  are able to rotate relative to front cover  944  and back cover  940  as needed depending upon the number of forward loose-leaves  72 A. When the binder  14  is closed, skeleton  50  is surrounded by back cover  940 , middle cover  142 , and front cover  944  so that rings  46  are not exposed thus making the binder  14  more attractive and easy to handle. 
     FIG. 15 
     FIG. 15 is a bottom view of another preferred embodiment of a binder  15  of the present invention. The binder  15  comprises cover  1500  and skeleton  50 . Cover  1500  includes back cover  940 , front cover  944  and middle cover  1142 . Spine  53  of skeleton  50  is disposed within the middle cover  1142 . Skeleton  50  is able to rotate relative to back cover  940  because middle cover  1142  is preferably very thin and flexible and defines slots similar to the slots  258 A- 258 C of binder  5  shown in FIG.  5 A. When the binder  15  is open 360 degrees, thin and flexible middle cover  1142  folds flat and open conduits  156  and  256  receive spine  53  wrapped in part of middle cover  1142  to minimize or eliminate the lump caused by spine  53  so that back cover  940  can lie flat relative to front cover  944 . 
     FIG. 16 Description/Operation 
     FIG. 16A is a perspective view of yet a further embodiment of a binder  16  of the present invention. The binder  16  comprises cover  1600  and skeleton  50 . Cover  1600  includes middle cover  42 , front cover  44 , and back cover  1040 . Back cover  1040  defines margin supports  360 A- 360 D divided by openings  358 A- 358 C. Bridges  62  span openings  358 A- 358 C at edge  1040 A of back cover  1040 . Bridges  62  have a smaller thickness than back cover  1040  to enable rings  46  to stand upright when the binder  16  is closed. Skeleton  50  and rings  46  are able to rotate relative to back cover  1040 . By enabling rings  46  to stand upright when the binder  16  is closed and permitting spine  53  and rings  46  to adequately rotate relative to back cover  940  when the binder  16  is open 360 degrees, openings  358 A- 358 C are nearly functionally equivalent to slots  58 A- 58 C of the binder  1  of FIG.  1 A. 
     FIG. 17 
     FIG. 17 shows a perspective view of yet another preferred embodiment of a binder  17  of the present invention. The binder  17  comprises cover  1700  and skeleton  650 . Cover  1700  includes back cover  1140 , middle cover  1242 , and front cover  44 . The back cover  1140  defines slots  458 A and  458 B interspaced between margin supports  460 A- 460 C. As shown in FIG. 17, spine  653  of skeleton  650  is disposed within conduit  56 B defined by the top edge  1140 A of back cover  1140 . Middle cover  1242  is disposed between back cover  1140  and front cover  44 . Loose-leaves are flipped over the top edge  1140 A of back cover  1140  while middle cover  1242  and front cover  44  are flipped around the side edge  1140 B of back cover  1140  in order to minimize the footprint of the binder  17 . 
     FIGS. 18A-18B 
     FIGS. 18A and 18B are perspective and bottom views of another preferred embodiment of a binder  18  of the present invention. The binder  18  comprises cover  1800  and skeleton  50 . Cover  1800  includes front cover  44 , back cover  1240  and a bi-planar middle cover  1342 . Middle cover  1342  has middle cover portion  1342 A and middle cover portion  1342 B. As shown in FIG. 18A, middle cover portion  1342 A is disposed between front cover  44  and middle cover portion  1342 B which is disposed between middle cover portion  1342 A and back cover  1240 . Crease  1342 C is preferably disposed between front cover  44  and middle cover portion  1342 A and crease  1342 D is preferably disposed between middle cover portion  1342 A and middle cover portion  1342 B. Middle cover portion  1342 B and back cover  1240  each define half of the total area of slots  558 A- 558 C interspaced between margin supports  560 A- 560 D. The perimeters of slots  558 A- 558 C are closed and completely surrounded by middle cover portion  1342 B and back cover  1240 . 
     Slots  558 A- 558 C are roughly O-shaped and exposed when the binder  18  is closed. The slots  558 A- 558 C fold in half along a fold  1342 E between middle cover portion  1342 B and back cover  1240  to become roughly U-shaped when front cover  44 , middle cover portion  1342 A and middle cover portion  1342 B are flipped back against back cover  1240  to minimize the footprint of the binder  18  as shown in FIG.  18 B and in dotted lines in FIG.  18 A. The folding of slots  558 A- 558 C prevents back cover  1240 , middle cover portion  1342 A and middle cover portion  1342 B from interfering with the rotation of rings  46  through the plane of back cover  1240 . When cover  1800  is folded flatly open 360 degrees, a portion of each ring  46  is rotatable around the near-ring edge  1240 A. 
     This construction of the binder  18  does not require the attachment of middle cover portion  1342 B to the wide portion of back cover  1240  as divided by conduit  56 . As shown in FIG. 18B, one edge of middle cover portion  1342 B is connected to the edge  1240 A of back cover  1240  near margin supports  560 A- 560 D. The fold  1342 E adjacent to back cover  1240  can be relocated to enable the edge of middle cover portion  1342 B to interface to the edge  1240 A of back cover  1240  on either side of back cover  1240  as divided by conduit  56 . Forward loose-leaves  72 A and latter loose-leaves  72 B and pads  61 A and  61 B lie parallel and flat when the binder  18  is open 360 degrees as shown in FIG.  18 B. 
     FIGS. 19A-19C 
     FIGS. 19A-19C are perspective and bottom views, respectively, of yet another preferred embodiment of a binder  19  of the present invention. The binder  19  comprises cover  1900  and skeleton  50 . Cover  1900  includes back cover  1340 , middle cover  1442  and front cover  44 . Middle cover  1442  has portions  1442 A- 1442 D. Back cover  1340  defines margin supports  660 A- 660 D and half of the area of each of the slots  658 A- 658 C, the other halves of which being defined by the middle cover portion  1442 B. Unlike the margin supports  560 A- 560 D of the binder  18  shown in FIGS. 18A-18B, the margin supports  660 A- 660 D have the same thickness as the back cover  1340  and are shorter than margin supports  560 A- 560 D of the binder  18 . Like the slots  558 A- 558 C of the binder  18  shown in FIGS. 18A-18B, slots  658 A- 658 C fold in half along the fold  282 A between middle cover portion  1442 B and back cover  1340  when the binder  19  is open 360 degrees. Slot cover  64 , having middle cover portions  1442 C and  1442 D, attaches to middle cover portion  1442 B and back cover  1340  and completely spans slots  658 A- 658 B to hide them when the binder  19  is closed as shown in FIG.  19 B. Slot cover  64  defines a crease  282 B between middle cover portions  1442 C and  1442 D which allows it to fold neatly away from slots  658 A- 658 C when the binder  19  is open 360 degrees. 
     FIGS. 20A-20C 
     FIGS. 20A-20C are a perspective and two bottom views, respectively, of yet another preferred embodiment of a binder  20  of the present invention. The binder  20  comprises cover  2000  and skeleton  50 . Cover  2000  includes front cover  1044 , middle cover  1542 , and back cover  1440 . Middle cover  1542  has middle cover portions  1542 A- 1542 F that are connected together to define conduit  356 . Skeleton  50  is disposed within conduit  356  such that rings  46  are looped through middle cover holes  74 C- 74 D. Conduit  356  changes shape as front cover  1044  is opened relative to back cover  1440 . Middle cover portions  1542 A- 1542 D snugly enwrap spine  53  as the binder  20  is opened 360 degrees as seen in FIG.  20 C. Spine  53  is a pivot about which cover  2000  can rotate when cover  2000  is flatly-folded open 360 degrees. As the binder  20  is opened from its closed position to its 360 degree position, front cover  1044  and middle cover portion  1542 A rotate about fold  382 A and spine  53  until they abut back cover  1440  and middle cover portion  1542 D, respectively. When cover  2000  is folded flatly open 360 degrees, a transient near-ring edge coinciding with fold  382 A exists and a portion of each ring  46  is rotatable about this edge. 
     Middle cover portions  1542 A and  1542 D, front cover portion  1044 A and back cover portion  1440 A are preferably the same thickness so as to form parallel planar surfaces when binder  20  is open 360 degrees. Middle cover portions  1542 B and  1542 C have reduced thickness relative to middle cover portions  1542 A and  1542 D to accommodate spine  53  when the binder  20  is open 360 degrees. Front cover  1044  has front cover portions  1044 A and  1044 B. Back cover  1440  has back cover portions  1440 A and  1440 B. The thickness of front cover portion  1044 B and back cover portion  1440 B is less than the thickness of front cover portion  1044 A and back cover portion  1440 A, respectively, so that a channel  65  is formed when the binder  20  is open 360 degrees as seen in FIG.  20 C. Channel  65  accommodates ring-hole cover  164  that folds neatly via crease  382 B into channel  65  as the binder  20  is opened 360 degrees. Ring-hole cover  164  includes middle cover portions  1542 E- 1542 F and hides rings  46  and middle cover holes  74 C- 74 D when the binder  20  is in its closed position as seen in FIG. 20B to give the binder  20  the aesthetic appearance and handling of a bound book. The binder  20  is similar to the binder  5  in that the thickness of the folded middle cover  1542  is substantially equal to the sum of the thickness of front cover  1044  and back cover  1440  as seen when the binder is open 360 degrees in FIG.  20 C. 
     FIGS. 21A-21B 
     FIGS. 21A-21B are bottom views of yet another preferred embodiment of a binder  21  of the present invention. The binder  21  comprises cover  2100  and skeleton  50 . Cover  2100  includes front cover  1044 , middle cover  1642  and back cover  1440 . Middle cover  1642  has middle cover portions  1642 A- 1642 D. Middle cover portion  1642 B contains conduit  456 B. Spine  53  of skeleton  50  is disposed within conduit  456 B and creates middle cover lump  67  in middle cover portion  1642 B. Middle cover portion  1642 A contains conduit  456 A which receives middle cover-lump  67  when the binder  21  is open 360 degrees as shown in FIG.  21 B. Rings  46  are looped through middle covers  1642 A- 1642 B of the binder  21  in a similar manner as rings  46  are looped through middle covers  1542 A- 1542 B of the binder  20 . 
     As the binder  21  is opened from its closed position in FIG. 21A to its 360 degree position in FIG. 21B, front cover  1044  and middle cover portion  1642 A rotate about fold  482 A until they abut back cover  1440  and middle cover  1642 B, respectively, to minimize the footprint of the binder  21 . Middle cover  1642 A, middle cover  1642 B, front cover  1044  and back cover  1440  form parallel planar surfaces when the binder  21  is open 360 degrees. Front cover  1044  has front cover portions  1044 A and  1044 B. Back cover  1440  has back cover portions  1440 A and  1440 B. The thickness of front cover portions  1044 B and back cover portions  1440 B is less than the thickness of front cover portions  1044 A and back cover portions  1440 A, respectively, so that a channel  165  is formed when the binder  21  is open 360 degrees as seen in FIG.  21 B. Channel  165  accommodates ring-hole cover  264  that folds neatly via crease  482 B into channel  165  as the binder  21  is opened 360 degrees. Ring-hole cover  264 , having middle cover portions  1642 C- 1642 D, gives the binder  21  the aesthetic appearance and handling of a bound book when the binder  21  is closed as seen in FIG.  21 A. The binder  21  is similar to the binder  5  and the binder  20  in that the thickness of the folded middle cover  1642  is substantially equal to the sum of the thickness of front cover  1044  and back cover  1440  as seen when the binder  21  is open 360 degrees in FIG.  21 B. 
     FIGS. 22A-22B 
     FIGS. 22A-22B are bottom views of yet another preferred embodiment of a binder  22  of the present invention. The binder  22  comprises cover  2200  and skeleton  50 . Cover  2200  includes front cover  1044 , middle cover  1742  and back cover  1540 . Middle cover  1742  includes middle cover portions  1742 A- 1742 D. Rings  46  are looped through middle cover portions  1742 A- 1742 B of the binder  22  in a similar manner as rings  46  are looped through middle cover portions  1542 A- 1542 B of the binder  20 . However, middle cover portions  1742 A- 1742 B are releasably bound to rings  46  in the same manner as loose-leaves  72  are releasably bound to rings  46 . 
     As the binder  22  is opened from its closed position in FIG. 22A to its 360 degree open position in FIG. 22B, front cover  1044  and middle cover portion  1742 A rotate about fold  582 A until they abut back cover  1540  and middle cover  1742 B, respectively, to minimize the footprint of the binder  22 . Middle cover portion  1742 A, middle cover portion  1742 B, front cover  1044 , writing-support pad  161  and back cover  1540  form parallel planar surfaces when the binder  22  is open 360 degrees. Writing-support pad  161  has portions  161 A- 161 B where  161 B is of reduced thickness relative to  161 A to hinder spine  53  from causing a lump in the writing surface. Front cover  1044  has front cover portions  1044 A and  1044 B. Back cover  1540  includes back cover portions  1540 A-C. The thickness of back cover portion  1540 C is reduced relative to back cover portion  1540 B so as to accommodate spine  53  when the binder  22  is in the closed position. The thickness of front cover portion  1044 B and back cover portion  1540 B is less than the thickness of front cover portion  1044 A and back cover portion  1540 A, respectively, so that a channel  265  is formed when binder  22  is open 360 degrees as seen in FIG.  22 B. Channel  265  accommodates ring-hole cover  364  that folds along crease  582 B into channel  265  as the binder  22  is opened 360 degrees. Ring-hole cover  364  has middle cover portions  1742 C- 1742 D and gives the binder  22  the aesthetic appearance and handling of a bound book when the binder  22  is closed as seen in FIG.  22 A. 
     FIGS. 23A-23E 
     FIGS. 23A-23E are bottom views of yet another preferred embodiment of a binder  23  of the present invention. The binder  23  comprises skeleton  550 , one or more staple-thin fasteners  68  and cover  2300 . Cover  2300  includes front cover  1144 , middle cover  1842  and back cover  1640 . Middle cover  1842  has middle cover portions  1842 A- 1842 C. Skeleton  550  includes spine  553  and rings  746 . 
     Conventional spine  553  has an arc-shaped cross-section and has a switching element to simultaneously open and close rings  746 . Skeleton  550  is fixed to middle cover portion  1842 B via one or more staple-thin fasteners  68 . Middle cover portion  1842 B is of reduced thickness relative to middle cover portion  1842 A and middle cover portion  1842 C preferably creating recess  71  to contain spine  553 . Recess  71  aids in providing a flat writing surface when the binder  23  is open 180 degrees by lowering spine  553  partially into the plane of front cover  1144  and back cover  1640 . The reduced thickness of middle cover portion  1842 B also facilitates its greater flexibility relative to middle cover portions  1842 A and  1842 C enabling it to have a small radius of curvature illustrated in FIGS. 23C-23E such that middle cover portion  1842 A is able to lie flatly against middle cover portion  1842 C. Furthermore, fastener  68  is purposefully staple-thin so as not to hinder the folding of middle cover  1842 . The folding of middle cover  1842  creates a transient near-ring edge  73  in cover  2300 . To facilitate the flipping of front cover  1144  and one or more forward loose-leaves  72 A 360 degrees such that they lie parallel to back cover  1640  and latter loose-leaves  72 B, skeleton  550  must be able to incrementally rotate in a stable and controlled manner relative to front cover  1144  and back cover  1640 . Because skeleton  550  is fastened to middle cover portion  1842 B, it cannot freely rotate relative to middle cover portion  1842 B; but skeleton  550  rotates relative to front cover  1144  and back cover  1640  via the flexibility of middle cover portion  1842 B. As illustrated in FIGS. 23C-23E, skeleton  550  is not strongly biased to a particular angular position when front cover  1144  is flipped 360 degree beneath back cover  1640  and can incrementally rotate as needed depending upon the number of forward loose-leaves  72 A to be flipped beneath back cover  1640 ; back cover  1640  and middle cover portion  1842 A slide against front cover  1144  and middle cover portion  1842 B to facilitate the amount of necessary rotation of skeleton  550 . Staple-thin fasteners  68  can be affixed loosely to allow freer rotation of skeleton  550  relative to middle cover portion  1842 B. To provide a flat writing surface, writing-support pads  61 A and  61 B blanket crevices  75 A- 75 B between spine  553  and middle cover portions  1842 A and  1842 C, respectively. 
     When cover  2300  is open 360 degrees, spine  553  is rotatably disposed on middle cover  1842  such that rings  746  of skeleton  550  can rotate about near-ring edge  73  of the flatly-folded cover  2300 . Since spine  553  is riveted to cover  2300 , it is not a pivot about which cover  2300  can rotate. However, when the binder  23  is flatly folded open 360 degrees, the flexibility and small radius of curvature of middle cover  1842  enable spine  553  to be substantially axially disposed relative to the rotation of rings  746  and the oppositely rotating front cover  1144  and back cover  1640 . All points of front cover  1144 , back cover  1640 , and rings  746  rotate through substantially the same size angle about spine  553  as most of the flatly-folded cover  2300  rotates about spine  553 . In this case, front cover  1144  and back cover  1640  share the same angular rotation about spine  553  even though front cover  1144  and back cover  1640  slide radially in opposite directions relative to spine  553 . 
     Front cover  1144  comprises front cover portions  1144 A- 1144 B and back cover  1640  comprises back cover portions  1640 A- 1640 B. Front cover portion  1144 B is of reduced thickness enabling the folding of front cover portion  1144 A beneath middle cover  1842  and back cover  1640  as shown in FIG.  23 B. Likewise, back cover portion  1640 B is of reduced thickness enabling the folding of back cover portion  1640 A beneath middle cover  1842  and front cover  1144 . 
     The binder  23  is similar to the binder  5  in that the thickness of the folded middle cover  1842  is substantially equal to the sum of the thickness of front cover  1144  and back cover  1640  as seen when the binder is open 360 degrees in FIGS. 23C-23E. Moreover, the LSCPL of spine  553  is less than or equal to sum of the thickness of front cover  1144  and back cover  1640  which minimizes or eliminates any potential lump caused by spine  553  when it is positioned between forward loose-leaves  72 A and latter loose-leaves  72 B when the binder  23  is open 360 degrees. Also the major diameter of the rings  746  is much larger than the LSCPL dimension of spine  553 . The many elements of the binder  23  described in detail above work in concert to enable front cover  1144  and forward loose-leaves  72 A to lie flat and parallel to back cover  1640  and latter loose-leaves  72 B when the binder  23  is opened 360 degrees. 
     As the binder  23  is opened from its closed position to its 360 degree position, front cover  1144  and middle cover portion  1842 A rotate about middle cover portion  1842 B until they abut back cover  1640  and middle cover portion  1842 C, respectively, as shown in FIGS. 23C-23E. Middle cover portion  1842 A, middle cover portion  1842 C, front cover portion  1144 A and back cover portion  1640 A are preferably the same thickness to form parallel planar surfaces when the binder  23  is open 360 degrees. 
     Partially elliptical rings  746  have a major diameter that is greater than or equal to the sum of their cut-off minor diameter plus the LSCPL of spine  553 . This enables the loose-leaf capacity of rings  746  when the binder  23  is open 360 degrees to be greater than or equal to the capacity of the binder  23  when it is open 180 degrees and is typically loaded. 
     FIGS. 24A-24C 
     FIGS. 24A-24C are bottom views of yet another preferred embodiment of a binder  24  of the present invention. The binder  24  comprises skeleton  550 , one or more round rivets  69 , and cover  2400 . Cover  2400  includes front cover  1144 , middle cover  1942 , and back cover  1640 . The binder  24  comprises the same skeleton  550 , front cover  1144  and back cover  1640  as the binder  23  shown in FIGS. 23A-23E, but incorporates a different middle cover  1942  and round rivets  69  in place of middle cover  1842  and staple-thin fasteners  68  of the binder  23 . Skeleton  550  is fixed to middle cover  1942  via round rivets  69 . Middle cover  1942  includes middle cover portions  1942 A- 1942 C. Like middle cover portion  1842 B, middle cover portion  1942 B is of reduced thickness relative to middle cover portions  1942 A and  1942 C. But middle cover portion  1942 B of the binder  24  is longer and thinner than middle cover portion  1842 B of the binder  23  which enables middle cover portion  1942 B to accommodate round rivets  69  as well as staple-thin fasteners  68 . Because middle cover portion  1942 B is thin and flexible, middle cover portion  1942 B prevents round rivets  69  from causing a lump between middle cover portions  1942 A and  1942 C by providing the extra room that round rivets  69  require relative to staple-thin fasteners  68 . Middle cover portion  1942 B is also shaped so as to deter the edges of round rivets  69  from cutting into and damaging middle cover  1942  during repeated usage of the binder  24 . To provide a flat writing surface, writing-support pads  61 A and  61 B blanket crevices  175 A- 175 B between spine  553  and middle cover portions  1942 A and  1942 C, respectively. 
     FIGS. 25A-25B 
     FIGS. 25A-25B are bottom views of yet another preferred embodiment of a binder  25  of the present invention. The binder  25  comprises skeleton  550 , one or more round rivets  69 , and cover  2500 . Cover  2500  includes front cover  44 , middle cover  2042 , and back cover  1740 . The binder  25  has the same skeleton  550  as the binder  23  shown in FIGS. 23A-23E. Back cover  1740  has portions  1740 A- 1740 D. Skeleton  550  is fixed to back cover  1740  via round rivets  69 . To facilitate the flipping of front cover  44  and one or more forward loose-leaves  72 A 360 degrees such that they lie parallel to back cover  1740  and latter loose-leaves  72 B, skeleton  550  must be able to incrementally rotate in a stable and controlled manner relative to front cover  44  and back cover  1740 . Because skeleton  550  is riveted to back cover portion  1740 D, it cannot freely rotate relative to back cover portion  1740 D; but skeleton  550  rotates relative to front cover  44  and most of back cover  1740  via a hinge joint  76  between back cover portions  1740 D and  1740 C. Thus rings  746  are rotatable about a near-ring edge of back cover portion  1740 C. Skeleton  550  is not strongly biased to a particular angular position when front cover  44  is flipped 360 degrees beneath back cover  1740 , as illustrated in FIG.  25 B. Skeleton  550  can incrementally rotate as needed depending upon the number of forward loose-leaves  72 A to be flipped beneath back cover  1740 . Spine  553  is substantially axially disposed relative to opposite rotations of large back cover portion  1740 A and rings  46 . Middle cover  2042  has middle cover portions  2042 A- 2042 B and is attached to the wide side of back cover  1740  as divided by hinge joint  76  such that middle cover  2042  does not interfere with the rotation of skeleton  550  as front cover  44  and forward loose-leaves  72 A are flipped beneath back cover portions  1740 A- 1740 C. 
     Back covers portions  1740 C- 1740 D are of reduced thickness relative to back cover portion  1740 A which aids in providing a flat writing surface when the binder  25  is open 180 degrees by lowering spine  553  partially into the plane of back cover portion  1740 A. Back cover portion  1740 B is a small wedge-shaped segment connecting back cover portion  1740 C with back cover portion  1740 A. To provide a flat writing surface, writing-support pads  61 A and  61 B blanket crevices  275 A- 275 B between spine  553  and back cover portion  1740 A as illustrated in FIG.  25 B. Rivet groove  70  accommodates round rivet  69  when the binder  25  is in its closed position. 
     The binder  25  is similar to other embodiments of the present invention in that the LSCPL of spine  553  is less than or equal to sum of the thickness of front cover  44  and back cover  1740 A which minimizes or eliminates any potential lump caused by spine  553  when it is positioned between forward loose-leaves  72 A and latter loose-leaves  72 B when binder  25  is open 360 degrees. The binder  25  is also similar to the binder  1  in the manner that its middle cover  2042  is attached to its back cover  1740  to avoid interfering with the rotation of its skeleton  550 . 
     FIGS. 26A-26C 
     FIGS. 26A-26C show perspective, bottom and front views, respectively, of another preferred embodiment of a skeleton  150  of the binder of the present invention with detailed sectional portions of the synchronized switching element  151  thereof. In this embodiment of a skeleton  150 , cable  34  and tube  154  serve as the first and second connective elements, respectively, of synchronized switching element  151 . Rings  146  have ring segments  146 A- 146 C. Ring segments  146 A and ring segments  146 B are attached to tube  154  via weld, braze, or other appropriate means. Ring segments  146 B are hollow and their conduits  33  are constricted at one end by ledges or stops  132 . Conduit  33  houses spring  131  and receives part of ring segment  146 C. Stop  132  supports one end of spring  131  which constantly exerts a pushing force on ring segments  146 C both when skeleton  150  is open or closed. 
     In the closed position shown in FIG. 26B, ring segments  146 C are pressed up against ring segments  146 A. Ring segments  146 C are capable, albeit constrained, to slide into ring segments  146 B which have the same curvature as ring segments  146 C. One end of ring segment  146 C defines an opening or needle eye  30 . Cable  34  comprises a trunk segment  34 A with three branch segments  34 B with each branch segment  34 B terminating with a loop  35 . Each conduit  33 , spring  131 , and stop  132  of the three ring segments  146 B of skeleton  150  are threaded by one of the branch segments  34 B of cable  34 . Each of ring segments  146 C is attached to cable  34  via a chain link between its needle eye  30  and a corresponding loop  35 . 
     FIG. 26C shows the trunk-end of cable  34  attaches to pull-lock  38  which has knob  38 A. Pull-lock  38  is also attached to spring  36 . Spring  36  is extended to its lock position through slot  37  when skeleton  150  is locked open as seen in FIG.  26 A and as shown in broken lines of FIG.  26 C. FIGS. 26A-26C show rings  146  to be circular. However, other ring shapes are possible as long as portions of ring segments  146 B and  146 C have the same curvature to enable retraction of ring segment  146 C into ring segment  146 B. 
     To open skeleton  150 , knob  38  A of pull-lock  38  is pulled away from tube  154  against the resistance of springs  131  until spring  36  spring locks into slot  37 . Meanwhile, pull-lock  38  pulls cable  34  which simultaneously retracts the three ring segments  146 C into the three ring segments  146 B to lock open all three rings  146 . 
     To close skeleton  150 , spring  36  is pressed in to release cable  34  which is dragged to its closed position by springs  131  which also extend the ring segments  146 C out of the ring segments  146 B until they hit up against the ring segments  146 A. Rings  146  stay closed because of the compression loading of springs  131 . 
     FIGS. 27A-27B 
     FIGS. 27A and 27B show perspective views of a further preferred embodiment of a skeleton  250  of the binder of the present invention, with detailed sectional portions showing the synchronized switching element  251  of skeleton  250 . Ring segments  46 A are attached to rod  252  via weld, braze or other appropriate means. Similarly, ring segments  46 B are attached to tube  254 . When rod  252  is assembled within tube  254 , the spaced ring segments  46 A protrude through similarly spaced slots  55  of tube  254 . Tube  254  rotates about rod  252  through a limited angle to open and close ring segments  46 A relative to ring segments  46 B. Cylindrical flanges  77  maintain the longitudinal axis of rod  252  coincident with the longitudinal axis of tube  254 . 
     Synchronized switching element  251  includes spring  97  which is torsionally loaded when skeleton  250  is either open or closed and which is always resisting the opening of ring segments  46 A relative to ring segments  46 B. Catch  98 A which is attached to, or integrally formed as a part of, rod  252  constrains one arm of torsion spring  97 , while catch  98 B which is attached to, or integrally formed as a part of, tube  254  constrains the other arm of torsion spring  97 . Ledge  27 A extends from rod  252  while ledge  27 B extends from tube  254 . Both ledge  27 A and ledge  27 B are in contact with wedge  26  which is able to longitudinally slide along, as well as rotate around, the rod  252 . Wedge  26  is kept in contact with ledge  27 A and ledge  27 B via push rod  76  and torsion spring  97 . Push rod  76  and push button  39  are on opposite ends of a two-state mechanical switch common to ball-point pens for extending and retracting the ball-point. In ball-point pens, this two-state mechanical switch depends upon the constant resistance of a compression spring; in skeleton  250 , the constant resistance is supplied by torsion spring  97  via linkages (rod  252  and ledges  27 A and  27 B) to wedge  26 . 
     When push rod  76  is in the retracted position shown in FIG. 27A, push button  39  is up and the rings are closed. When push button  39  is depressed or clicked down, push rod  76  is pushed and locked into its extended position. As push rod  76  is extended, it pushes on wedge  26  which angularly separates ledge  27 A from ledge  27 B which in turn forces rod  252  to rotate relative to tube  254  which causes ring segments  46 A to open relative to ring segments  46 B. Since push rod  76  is locked in place, ring segments  46 A remained locked open relative to ring segments  46 B as shown in FIG.  27 B. When push button  39  is depressed a second time, it unlocks push rod  76  from its extended position allowing torsion spring  97  to act upon rod  252  and tube  254  to close ring segments  46 A and ring segments  46 B as well as ledge  27 A and ledge  27 B as shown in FIG.  27 A. As ledge  27 A and ledge  27 B close, they force wedge  26  and push rod  76  to their closed and retracted positions, respectively, and push rod  76  forces push button  39  to its original up position. Although FIGS. 27A and 27B show some components of synchronized switching element  251  to be disposed on one end of skeleton  250 , corresponding mirror-image components of the synchronized switching element  251  may be disposed on the opposite end of skeleton  250  to provide more balanced operation. 
     FIGS. 28A-28B 
     FIGS. 28A and 28B show perspective views of yet another preferred embodiment of skeleton  350  of the binder of the present invention, with detailed sectional portions showing the synchronized switching element  351  of skeleton  350 . Ring segments  46 A are attached to rod  352  via weld, braze or other appropriate means. Similarly, ring segments  46 B are attached to tube  354 . When rod  352  is assembled within tube  354 , the spaced ring segments  46  A protrude through similarly spaced slots  55  of tube  354 . Tube  354  rotates about rod  352  through a limited angle to open and close ring segments  46 A relative to ring segments  46 B. Synchronized switching element  351  includes spring  97  which is torsionally loaded when skeleton  350  is either open or closed and which is always resisting the opening of ring segments  46 A relative to ring segments  46 B. Catch  98 A which is attached to, or integrally formed with, rod  352  constrains one arm of torsion spring  97  while catch  98 B which is attached to, or integral with, tube  354  constrains the other arm of torsion spring  97 . Stop  32  protrudes from the inner wall of tube  354 . Spring  31  which loosely spirals around rod  352  is compressed between stop  32  and push button  139 . Spring  31  always has some amount of compression loading, albeit less when skeleton  350  is in the open state. Cylindrical, hollow push button  139  can slide longitudinally along rod  352  a limited distance like a sleeve on a rod. Tooth  93 , which protrudes from the inner wall of push button  139  into groove  94  of rod  352 , constrains push button  139  to rotate in sync with rod  352 . Pawl  95  protrudes from the outer wall of push button  139  and slides along the limited path of ledge  96 . Pawl  95  constrains to the longitudinal and rotational motion of push button  139 . Ledge  96  protrudes from the inner wall of tube  354 . Stop  32  also acts as a flange to maintain the longitudinal axis of rod  352  coincident with the longitudinal axis of tube  354 . 
     To open skeleton  350 , ring segments  46 A and ring segments  46 B are pulled apart. This action causes rod  352  to rotate relative to tube  354  and is resisted by torsion spring  97 . As rod  352  rotates relative to tube  354 , push button  139  is constrained to rotate in sync because of its tooth  93  within groove  94 , but push button  139  is also pushed longitudinally towards rod  352  by a spiral section of ledge  96  that acts on pawl  95 . The movement of push button  139  towards rod  352  causes the compression of spring  31  between push button  139  and stop  32 . As rod  352  forces pawl  95  to rotate, pawl  95  is forced out of slot  96  A, slides over tooth  96 C of ledge  96  and is forced into slot  96 B by spring  31  thereby locking push button  139  in its extended state which corresponds to the open position of skeleton  350  as shown in FIG.  28 B. When pawl  95  is disposed in slot  96 B, the user can release the rings  46  because pawl  95  is obstructed from rotating back by the tooth  96 C of ledge  96  and thus pawl  95  is able to resist the torsional closing force of torsion spring  97 . 
     To close skeleton  350 , push button  139  is pressed towards rod  352  against the resistance of spring  31 . This action causes pawl  95  to move out of slot  96 B and slide over tooth  96 C of ledge  96  where the pawl  95  is then forced into slot  96 A by spring  31  which allows torsion spring  97  to act to close the rings  46  of skeleton  350 . Torsion spring  97  twists catch  98 A relative to catch  98 B causing rod  352  to rotate relative to tube  354  until ring segments  46 A are closed against ring segments  46 B. Although, FIGS. 28A and 28B show some components of synchronized switching element  351  to be disposed on one end of skeleton  350 , corresponding mirror-image components of synchronized switching element  351  may be disposed on the opposite end of skeleton  350  to provide more stable operation. 
     Skeleton embodiments  150 ,  250  and  350  can be used in place of skeleton embodiment  50  in each and every of the preferred embodiments that incorporate skeleton  50  of the present invention via a small modification to the covers to allow access to the actuators: knob  38 A, button  39  and button  139 . This modification is simply a hole in the top and bottom edges of the covers of the respective embodiments of the binders of the present invention. 
     FIGS. 29A-29C 
     FIGS. 29A-29B show perspective and side views, respectively, of a further preferred embodiment of a skeleton  450  of the binder of the present invention. FIG. 29C shows a side cross-sectional view of the rod  452  of skeleton  450 . Skeleton  450  comprises three rings  246  and rod  452 . FIG. 29C shows that rings  246  comprise ring segments  246 A and ring segments  246 B the ends of which define tabs  47  and slots  48 , respectively. Also, nubs  49 A and nubs  49 B protrude from ring segments  246 A and ring segments  246 B, respectively. Ring segments  246 A have a small hollow free end into which tabs  47  can be inserted. Skeleton  450  is assembled by inserting ring segments  246 A through holes  57  defined by skeleton  450  and sliding the rings  246  so that only nubs  49 A and not nubs  49 B pass through light-bulb shaped hole  57 . Then each ring  246  is rotated about the portion of ring  246  disposed within hole  57  to stand rings  246  upright relative to rod  452  as shown in FIG.  29 A. 
     Each ring  246  is opened or closed individually. To open ring  246 , tab  47  is pushed down relative to slot  48  and pulled out of the hollow tip of ring segment  246 A to unhitch tabs  47  from slots  48 . The body of ring  246  acts like a spring which is free of tension or compression in its open position as shown in FIG.  29 B. To close rings  246 , force is exerted to insert tabs  47  of ring segments  246 B into slots  48  of ring segments  246 A until the tabs  47  are hitched in slots  48  and locked therein by the spring loading of rings  246  that exists when rings  246  are in the closed position. Since the front covers of many of the preferred embodiments of the binders of the present invention often rests on the rings of the skeleton, the rotation of the tops of rings  246  towards skeleton  450  can help minimize binder thickness when the binder is closed. 
     FIGS. 30A-30F 
     FIG. 30A is the bottom view of another preferred embodiment of a ring component  346  of the present invention and FIGS. 30B-30F are bottom views of binder  1 , shown in FIGS. 1A-1L, with its skeleton  50  incorporating rings  346  in placed of rings  46 . FIGS. 30B-30F show rings  346  in different positions as varying numbers of forward loose-leaves  72 A are flipped beneath back cover  40 . 
     Ring  346  comprises ring segments  346 A- 346 B and the portion of spine  53  intersected by ring segments  346 A- 346 B. Ring segment  346 A has ring segments  346 P- 346 Q and ring segment  346 B has ring segments  346 R- 346 S. The shape of ring  346  is a cut-off ellipse that is derived from an ellipse and chord P 1 Q 1  parallel to its major axis. Rings segments  346 Q and  346 S coincide with chord P 1 Q 1 . The ellipse&#39;s minor axis bisects chord P 1 Q 1  on one side of the major axis and bisects spine  53  on the opposite side of the major axis. 
     Distance A 1  is the upright-ring loose-leaf capacity measured from the interior surface  40 N of back cover  40  to point Q 1  when rings  346  are upright as shown in FIGS. 30A and 30B. When rings  346  are upright, ring segments  346 Q and  346 S are parallel to back cover  40 . Distance E 1  is the length of the major axis of the interior cut-off ellipse of ring  346  as shown in FIG.  30 A. FIGS. 30C-30F show that back cover  40  and front cover  44  occupy additional interior ring space when forward loose-leaves  72 A are flipped 360 degrees beneath back cover  40  that they do not occupy when rings  346  are upright as in FIG.  30 B. The space occupied by back cover  40  and front cover  44  is measured by distance D 1  as shown in FIG.  30 D. Distance (B 1 +C 1 ) measures the loose-leaf capacity of the rings when spine  53  is rotated 90 degrees as shown in FIG.  30 D. 
     Cover  100  of FIGS. 30B-30F is preferably loaded and unloaded with loose-leaves when cover  100  is open 180 degrees and rings  346  are substantially upright. Therefore, the height of the upright rings  346  determines the capacity of rings  346  as users will fill the rings up to the under surface of the ring segments  346 Q and  346 S. For convenient operation of the binder, it is preferred that the upright-ring loose-leaf capacity be less than or equal to the loose-leaf capacity when the spine  53  is rotated to other positions shown in FIGS. 30C-30F. To enable rings  346  to have less or the same loose-leaf capacity when rings  346  are upright as when spine  53  and rings  346  are rotated 90 degrees from upright, the following equation must be satisfied: 
     
       
           A 1 =&lt;B 1 +C 1  equation 1 
       
     
     From FIG. 30D, major axis distance E 1  equals the sum of distances B 1 , C 1 , and D 1 . 
     
       
           E 1 =B 1 +C 1 +D 1  equation 2 
       
     
     Substituting equation 2 into equation 1 and rearranging terms yields: 
     
       
           E 1 &gt;=A 1 +D 1 
       
     
     For a given thickness of back and front cover as measured by distance D 1  and for a given upright-ring loose-leaf capacity A 1 , the length of the major axis E 1  of ring  346  can be calculated so that the loose-leaf capacity of rings  346  in the upright position is greater than or equal to the loose-leaf capacity of rings  346  when spine  53  and loose-leaf ring  346  are rotated 90 degrees from upright. More stringently, chord P 1 Q 1  can cut the elliptical curve of rings  346  at a position such that the upright-ring loose-leaf capacity is less than or equal to the loose-leaf capacity of rings  346  for the range of spine rotation illustrated in FIGS. 30B-30F. The preferred length of E 1  is its maximum value that satisfies this more stringent constraint. 
     Completely elliptical rings immediately decrease in loose-leaf capacity as spine  53  begins to rotate and ring prongs enter the plane of the back cover  40  of binder  1 . Cut-off elliptical rings  346  do not share this problem because point Q 1  which determines upright-ring capacity of rings  346  extends farther from back cover  40  as spine  53  rotates counterclockwise from upright until point Q 1  is directly over spine  53 . 
     FIGS. 31A-31F 
     FIG. 31A is the bottom view of another preferred embodiment of a ring component  446  of the present invention and FIGS. 31B-31F are bottom views of binder  1 , shown in FIGS. 1A-1L, with its skeleton  50  incorporating rings  446  in placed of rings  46 . FIGS. 31B-31F show rings  446  in different positions as varying numbers of forward loose-leaves  72 A are flipped beneath back cover  40 . Ring  446  comprises ring segments  446 A- 446 B and the portion of spine  53  intersected by ring segments  446 A- 446 B. Ring segment  446 A comprises ring segments  446 P- 446 R and ring segment  446 B comprises ring segments  446 S- 446 U. The shape of ring  446  is a cut-off ellipse similar to ring  346  with additional chord ring segments  446 P and  446 S parallel to the major axis of the elliptical curve of rings  446 . When binder  1  of FIGS. 31A-31F is open 180 degrees, middle cover  42  presses against the flat ring segments  446 P and  446 S to urge rings  446  to stand upright. 
     FIGS. 32A-32F 
     FIG. 32A is the bottom view of another preferred embodiment of a ring component  546  of the present invention and FIGS. 32B-32F are bottom views of binder  1 , shown in FIGS. 1A-1L, with its skeleton  50  incorporating rings  546  in placed of rings  46 . FIGS. 32B-32F show rings  546  in different positions as varying numbers of forward loose-leaves  72 A are flipped beneath back cover  40 . Ring  546  comprises ring segments  546 A- 546 B and the portion of spine  53  intersected by ring segments  546 A- 546 B. 
     Ring segment  546 A has ring segments  546 P- 546 R and ring segment  546 B has ring segments  546 S- 546 U. Mostly elliptical ring segments  546 P and  546 S are joined to straight ring segments  546 Q and  546 T, respectively. Straight ring segments  546 Q and  546 T are bridged by straight ring segments  546 R and  546 U to complete rings  546 . Straight ring segments  546 Q,  546 R,  546 U, and  546 T constitute a multiple-line perimeter segment. The two angles that straight ring segments  546 Q and  546 T make with the major axis of the partial ellipse of ring  546  are not arbitrary. Straight ring segments  546 Q and  546 T are made intentionally parallel to lines X 1  and Y 1 , respectively. Line X 1  is a tangent line to spine  53  and ring segment  546 S and line Y 1  is a tangent line to spine  53  and ring segment  546 P. When rings  546  are in their upright position, line X 1  is in the plane of the exterior surface  40 X of back cover  40  and ring segment  546 Q is parallel as shown in FIG.  32 B. Distance A 2  measured from the interior surface  40 N of back cover  40  to the under surface of rings segment  546 Q is the upright-ring loose-leaf capacity of rings  546 . Similar to rings  346 , rings  546  are wider than tall such that the upright-ring loose-leaf capacity of rings  546  is less than or equal to the loose-leaf capacity of rings  546  for the range of spine rotation illustrated in FIGS. 32B-32F. Rings  546  rotate through a smaller angular range in FIGS. 32B-32F than rings  346  rotate in FIGS. 30B-30F. Cover  100  of FIGS. 32B-32F is preferably loaded and unloaded with loose-leaves when cover  100  is open 180 degrees and rings  546  are substantially upright. 
     FIGS. 33A-33F 
     FIG. 33A is the bottom view of another preferred embodiment of a ring component  646  of the present invention and FIGS. 33B-33F are bottom views of binder  1 , shown in FIGS. 1A-1L, with its skeleton  50  incorporating rings  646  in placed of rings  46 . FIGS. 33B-33F show rings  646  in different positions as varying numbers of forward loose-leaves  72 A are flipped beneath back cover  40 . Rings  646  are very similar to rings  546  but have less straight ring segments and are partially circular. 
     Ring  646  comprises ring segments  646 A- 646 B and the portion of spine  53  intersected by ring segments  646 A- 646 B. Ring segment  646 A has ring segments  646 P- 646 Q and ring segment  646 B has ring segments  646 R- 646 S. Mostly circular ring segments  646 P and  646 R are joined to straight ring segments  646 Q and  646 S, respectively. Straight ring segments  646 Q and  646 S are parallel with lines X 2  and Y 2 , respectively, and constitute a multiple-line perimeter segment. Line X 2  is a tangent line to spine  53  and ring segment  646 R and line Y 2  is a tangent line to spine  53  and ring segment  646 P. When rings  646  are in their upright position, line X 2  is in the plane of the exterior surface  40 X of back cover  40  and ring segment  646 Q is parallel as shown in FIG.  33 B. Distance A 3  measured from the interior surface  40 N of back cover  40  to the under surface of rings segment  646 Q is the upright-ring loose-leaf capacity of rings  646 . Similar to rings  346 , rings  646  are wider than tall such that the upright-ring loose-leaf capacity of rings  646  is less than or equal to the loose-leaf capacity of rings  646  for the range of spine rotation illustrated in FIGS. 33B-33F. Rings  646  rotate through a smaller angular range in FIGS. 33B-33F than rings  346  rotate in FIGS. 30B-30F. Cover  100  of FIGS. 33B-33F is preferably loaded and unloaded with loose-leaves when cover  100  is open 180 degrees and rings  646  are substantially upright. 
     FIG. 34 
     FIG. 34 is the bottom view of another preferred embodiment of a ring component  746  of the present invention. Ring  746  is very similar to ring  346  except that spine  553  is incorporated in place of spine  53 . Ring  746  comprises ring segments  746 A- 746 B and the portion of spine  553  intersected by ring segments  746 A- 746 B. Ring segments  746 A and  746 B closely correspond in shape and function to ring segments  346 A and  346 B of FIGS. 30A-30F. Rings  746  are incorporated in binders  23 - 25  shown in FIGS. 23A-25B where the skeleton is fixed to the cover with a fastener or rivet. 
     FIG. 35 
     FIG. 35 is the bottom view of another preferred embodiment of a ring component  846  of the present invention. Ring  846  is very similar to ring  546  except that spine  553  is incorporated in place of spine  53 . Ring  846  comprises ring segments  846 A- 846 B and the portion of spine  553  intersected by ring segments  846 A- 846 B. Ring segments  846 A and  846 B closely correspond in shape and function to ring segments  546 A and  546 B of FIGS. 32A-32F. Rings  846  can be incorporated in binder  25  shown in FIGS. 25A-25B where the skeleton is fixed to back cover  1740 D with a rivet. 
     The invention provides for a minimal footprint during use without sacrificing other popular advantages common to loose-leaf binders. The binder provides the minimal footprint capability with minimal tearing stress on the loose-leaves, a flat writing surface and the ability to simultaneously open or close all rings of the binder via an actuator. 
     While my above descriptions contain many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of several preferred embodiments thereof. Many other variations are possible. For example, all twenty-five binder embodiments with a SOCRA skeleton can instead use a skeleton having independently-openable rings. The cover embodiments with conduits that contain spine  53  can be joined with rings that are not connected by a spine; for example, skeleton  450  could be cut into three segments via cuts between its rings and then each segment placed end-to-end in conduit  56  as when they are unified. Other spineless embodiments are easily created from binders  13 ,  14  and  20  by eliminating skeleton  50  and inserting unconnected, independently-openable rings in place of rings  46  of these binders. Skeletons with more rings can be substituted by adding a corresponding number of slots to the binder cover. Skeletons with a synchronized switching element different from those disclosed herein may be substituted. Furthermore, a synchronized switching element that opens or closes all the rings simultaneously can be replaced by a sequential switching element that opens or closes all the rings sequentially. Margin supports can be eliminated especially when writing-support pads are included. Binder  1  can be modified by eliminating its middle cover segment and attaching a wider unsegmented flexible front cover directly to back cover  40  at the location of seam  66 . The skeleton of FIGS. 26A-26C can be modified so that its rings can pitch back and forth like the skeleton of FIG. 29A to enable reduced binder thickness when the binder is not filled to capacity. The binder of FIG. 8 could have a second loops flap attached to its middle cover to provide an alternative attachment to the back cover. Other variants comprise a skeleton with rings that can rotate relative to its spine&#39;s longitudinal dimension while a portion of its spine is held still. One such variant comprises a spine with a rectangular cross-section with a height equal to the thickness of its back cover and where the spine rigidly attaches along one edge of the back cover flush with the interior and exterior surfaces of the back cover to extend the back cover writing surface; the spine connects binder rings which can rotate about the spine&#39;s longitudinal dimension through slots in the spine. A second such variant can be made simply by placing spine  53  of skeleton  50  in a sleeve with slots corresponding to rings  46  that allow spine  53  to rotate relative to the sleeve; the sleeve which is part of this variant&#39;s spine can be rigidly riveted to a cover but still allow spine  53  contained therein and rings  46  to rotate relative to the cover. This use of a fixed sleeve may include the previous variant above where the sleeve is designed with a rectangular cross-section, and having spine  53  of skeleton  50  disposed within and rotatable relative to the rectangular sleeve while the sleeve is held still. Another variant, which lacks a distinct skeleton component, has a cover which is integrally formed with a synchronized switching element for simultaneously opening and closing its rings and which folds flat when open 360 degrees, and has rings that can rotate around a near-ring edge of the flatly-folded cover when the cover is open 360 degrees. 
     FIGS. 36A-36F 
     FIGS. 36A-36F show perspective and bottom views with a detailed sectional portion of a further preferred embodiment of a skeleton  650  and its components of the binder of the present invention. Ring segments  46 A are attached to rod  652 A via weld, braze, casting or other appropriate means. Similarly, ring segments  46 B are attached to rod  652 B. When rod  652 A is assembled alongside rod  652 B within wrap housing  41  to form spine  653 , the spaced ring segments  46 A and  46 B protrude through similarly spaced slots  155 A and  155 B, respectively, of wrap housing  41 . Slots  155 A and  155 B are integrally formed with housing-slot arch  112 . Slots  155 A and  155 B closely bound ring segments  46 A and  46 B to prevent longitudinal motion of rod  652 A relative to rod  652 B. Rods  652 A and  652 B rotate adjacent to each other in opposite directions through a limited angle to open and close ring segments  46 A relative to ring segments  46 B of rings  46 . Since rods  652 A and  652 B cannot move longitudinally relative to each other, ring segments  46 A and  46 B of ring  46  open and close transversely relative to spine  653 . Rods  652 A and  652 B have cross-sections that are preferably circular or slightly elliptical, having widths and heights that are of similar size so that the width and height of the resultant spine are similar in magnitude, preferably neither dimension being more than double the size of the other, thus keeping the resultant spine suitable for pivotal insertion in a conduit of a cover segment (FIGS.  45 B- 45 C). Or more broadly stated, each rod  652 A and  652 B has a cross-section with a major dimension and minor dimension that are roughly perpendicular and that are similar in magnitude so that the major dimension and minor dimension of the cross-section of the resultant spine are similar in magnitude. 
     Roughly L-shaped torque levers  45 A and  45 B are integrally formed with or are attached to the ends of rods  652 A and  652 B, respectively, by weld, braze, casting, or other appropriate means. Torque levers  45 A and  45 B, which are spanned by tensile spring  83  of spreader  59 , have elongated stems that extend transversely from spine  653  and its component rods  652 A and  652 B. Consequently, torque levers  45 A and  45 B are highly effective in transforming the tensile force exerted by spring  83  into strong opposing torsional forces, which act on rods  652 A and  652 B when rings  46  are opened and closed or are in the process of being either opened or closed. For example, when skeleton  650  is closed, springs  83  pull torque levers  45 A and  45 B towards each other, which is transmitted as opposing static torque to rods  652 A and  652 B, which in turn, is transmitted as opposing static forces on the free ends of rings  46 A and  46 B to keep rings  46  closed. Torque levers  45 A and  45 B provide for robust closure of rings  46 . 
     FIG. 36E shows a bottom view of skeleton  650  with a detailed sectional portion showing components of the synchronized switching element or actuator  451  of skeleton  650 . Actuator  451  comprises rods  652 A and  652 B, torque levers  45 A and  45 B, and spreader  59 . In this embodiment of a skeleton  650 , rods  652 A and  652 B serve as the first and second connective elements, respectively, of actuator  451 . Spring-loaded spreader  59  includes spring  83  housed within telescopic capsule  85  and thus is able to extend and retract. Retraction of spreader  59  is limited by stop  232 . FIG. 36F shows Telescopic capsule  85  has pinholes  63 A and  63 B which receive the free ends of L-shaped torque levers  45 A and  45 B, respectively. One end of spreader  59  pivots about the free end of torque lever  45 A and the other end of spreader  59  pivots about the free end of torque lever  45 B. 
     Spring  83  of actuator  451  is tensilely loaded when skeleton  650  is either open or closed and spring  83  resists the opening of ring segments  46 A relative to ring segments  46 B when spring  83  is on the ring side of spine  653  (FIG.  36 E). However, spring  83  resists the closure of ring segments  46 A and  46 B when spring  83  is on the opposite side of spine  653  away from the free ends of ring segments  46 A and  46 B (FIG.  36 F). 
     To open skeleton  650 , middle rings  46 A and  46 B of skeleton  650  are pulled apart, which twists rods  652 A and  652 B, which in turn spreads torque levers  45 A and  45 B apart against the resistance of springs  83  until springs  83  travel from one side of spine  653  to the other side at which point springs  83  switch from exerting closure force on skeleton  650  to exerting opening force. When driven only by this opening force, Skeleton  650  continues opening until telescopic capsule  85  of spreader  59  retracts to its limit as set by stop  232 . 
     To close skeleton  650 , rings  46 A and  46 B are pushed toward each other against resistance of springs  83  until springs  83  travel from one side of spine  653  to the ring side of spine  653  at which point springs  83  switch from exerting opening force on skeleton  650  to exerting closure force. When driven only by this closure force, Skeleton  650  continues closing until the free ends of rings  46 A and  46 B abut each other. Rings  46  then remain closed because of the tensile loading of springs  83 . 
     FIGS. 37A-37D 
     FIGS. 37A-37D show perspective and bottom views of a further preferred embodiment of a skeleton  750  and its components of the binder of the present invention with detailed sectional portions of the actuator  551  thereof. Skeleton  750  comprises the same spine  653  and rings  46  as skeleton  650  shown in FIGS. 36A-36F, but incorporates different torque levers  145 A- 145 B and spreader  159 . Actuator  551  comprises rods  652 A and  652 B of spine  653 , torque levers  145 A and  145 B, and spreader  159 . In particular, FIG. 37A shows an exploded view of another preferred embodiment of a spring-loaded spreader  159 . Spreader  159  comprises telescopic capsule  185 , static pins  102 A- 102 B, slide pin  102 C, and tensile spring  83 . Capsule segment  185 A fits snugly into and can slide longitudinally within capsule segment  185 B. Capsule segment  185 A has guide slot  101 A and pinhole  163 A, which receives static pin  102 A. Capsule segment  185 B has guide slot  101 B and pinhole  163 B, which receives static pin  102 B. When spreader  159  is assembled and is part of skeleton  750 , slide pin  102 C is inserted within both guide slots  101 A and  101 B and is hooked by one end of spring  83 ; static pin  102 B is hooked by the other end of spring  83  and is inserted within pinhole  163 B of capsule segment  185 B as well as within hole  163 D of torque lever  145 B; and static pin  102 A is inserted within pinhole  163 A of capsule segment  185 A as well as within hole  163 C of torque lever  145 A. 
     To open skeleton  750 , middle rings  46 A and  46 B of skeleton  750  are pulled apart, which spreads torque levers  145 A and  145 B apart against the resistance of springs  83 . As torque levers  145 A and  145 B spread wider, capsule segment  185 A telescopically extends from capsule segment  185 B and the border of guide slot  101 A pushes slide pin  102 C along guide slot  101 B in the direction of static pin  102 A until it reaches the tip of pointed tooth  128  of guide slot  101 B. Upon clearing this tip, guide slot  101 A pushes slide pin  102 C in a new direction roughly toward spine  653 . After clearing this tip, slide pin  102 C will maintain spreader  159  in its extended position upon release of rings  46 A and  46 B, thus keeping rings  46  open (FIG.  37 D). 
     To close skeleton  750 , middle rings  46 A and  46 B of skeleton  750  are pushed toward each other, which brings torque levers  145 A and  145 B towards each other against the partial resistance of springs  83 . As torque levers  145 A and  145 B approach each other, capsule segment  185 A telescopically retracts within capsule segment  185 B and the border of guide slot  101 A pushes slide pin  102 C along guide slot  101 B in the direction away from spine  653  toward the tip of pointed tooth  128 . After clearing this tip, spring  83  drags slide pin  102 C along guide slot  101 B in the direction of static pin  102 B to retract spreader  159  until ring segments  46 A abut ring segments  46 B, thus closing rings  46  (FIG.  37 C). Springs  83  are still under tension when rings  46  are closed which provides for spring-loaded closure of skeleton  750 . 
     FIGS. 38A-38C 
     FIGS. 38A-38C show perspective and bottom views of a further preferred embodiment of a skeleton  850  of the binder of the present invention with detailed sectional portions of the actuator  651  thereof. Skeleton  850  comprises the same spine  653  and rings  46  as skeleton  650  shown in FIGS. 36A-36F, but incorporates different torque levers  145 A- 145 B and spreader  259 . Actuator  651  comprises rods  652 A and  652 B of spine  653 , torque levers  145 A and  145 B, and spreader  259 . FIG. 38B shows a sectional view of another preferred embodiment of a spring-loaded spreader  259 . Spreader  259  comprises telescopic capsule  285 , pins  102 A- 102 B, spin cylinder  103 A, slide cylinder  103 B, and tensile spring  83 . Capsule  285  includes capsule cylinder  285 A, which fits snugly into and can slide longitudinally within capsule segment  285 B. Slide cylinder  103 B fits in spin cylinder  103 A, which in turn fits in capsule cylinder  285 A. Capsule cylinder  285 A has pinhole  263 A, which receives pin  102 A and capsule segment  285 B has pinhole  263 B, which receives pin  102 B. When spreader  259  is assembled into skeleton  850 , pin  102 A is inserted within pinhole  263 A of capsule cylinder  285 A as well as within hole  163 C of torque lever  145 A (FIGS.  37 B and  38 A- 38 B) and is hooked by one end of spring  83 ; pin  102 B is hooked by the other end of spring  83  and is inserted within pinhole  263 B of capsule segment  285 B as well as within hole  163 D of torque lever  145 B. 
     Spin cylinder  103 A, slide cylinder  103 B, and Capsule cylinder  285 A are part of a two-state mechanical switch well known to ballpoint pens for extending and retracting the ballpoint. In ballpoint pens, this two-state mechanical switch depends upon the constant resistance of a compression spring; in skeleton  850 , the constant resistance is supplied by tensile spring  83  via linkages (pins  102 A- 102 B). Additionally, the characteristic push button cylinder of the ballpoint mechanism is adapted here to become slide cylinder  103 B, which is pulled by pin  102 B. This adaptation includes removing the portion of the push button cylinder that would protrude from the top of the ballpoint pen and adding the cylindrical portion of slide cylinder  103 B that penetrates spin cylinder  103 A and loops pin  102 B (FIG.  38 B). Instead of pressing a push button once to extend a ballpoint and a second time to retract it, ring segments  46 A and  46 B are pulled apart and released once to extend spreader  259 , which maintains rings  46  open, and are pulled apart and released a second time to retract spreader  259 , allowing rings  46  to close. The straight grooves and spiral ledges of spin cylinder  103 A, slide cylinder  103 B, and capsule cylinder  285 A, which characterize this two-state switch, are well known and are not illustrated in FIGS. 38A-38C. 
     To open skeleton  850 , middle rings  46 A and  46 B of skeleton  850  are pulled apart, which spreads torque levers  145 A and  145 B apart against the resistance of springs  83 . Spreading torque levers  145 A and  145 B separates pins  102 A and  102 B so that pin  102 B pulls slide cylinder  103 B away from capsule cylinder  285 A; concurrently, slide cylinder  103 B also pushes spin cylinder  103 A in the same direction and capsule cylinder  285 A telescopically extends from capsule segment  285 B. If the rings are pulled far enough apart and released, spin cylinder  103 A moves to its extended position to lock spreader  259  in its extended state under the force of spring  83 . When spreader  259  is locked in its extended state between torque levers  145 A and  145 B, rings  46  are kept open (FIG.  38 C). 
     To close skeleton  850 , middle rings  46 A and  46 B of skeleton  850  are pulled apart again and released. If pulled apart far enough and released under the force of spring  83 , spin cylinder  103 A moves to its retracted position enabling spreader  259  to retract as well such that capsule cylinder  285 A telescopically retracts within capsule segment  285 B. Torque levers  145 A and  145 B approach each other, until ring segments  46 A abut ring segments  46 B, thus closing rings  46  (FIG.  38 B). Springs  83  are still under tension when rings  46  are closed which provides for spring-loaded closure of skeleton  850 . 
     Spreader  259  can be assembled in an alternative way by attaching spring  83  to spin cylinder  103 A, instead of pin  102 B, by an appropriate attachment means that does not inhibit the spin action associated with spin cylinder  103 A during operation. When this alternative assembly is used, ring segments  46 A- 46 B can flop back and forth a limited distance when rings  46  are open and are not biased to a fixed position. 
     FIGS. 39A-39C 
     FIGS. 39A-39C show a front view of another preferred embodiment of a spreader  359  and bottom views of a further preferred embodiment of a skeleton  950  of the binder of the present invention. Skeleton  950  comprises the same spine  653  and rings  46  as skeleton  650  shown in FIGS. 36A-36F, but incorporates different torque levers  245 A- 245 B and spreader  359 . Skeleton  950  has actuator  751 , which comprises rods  652 A and  652 B of spine  653 , zigzag torque levers  245 A and  245 B, and spreader  359 . Spreader  359  is a bar having pinholes  363 A and  363 B, which receive torque levers  245 A and  245 B, respectively. Zigzag torque levers  245 A and  245 B have open and closed indentation positions for spreader  359 . 
     To open skeleton  950 , spreader  359  is slid along both torque levers from the closed indentation position (FIG. 39B) to the open indentation position (FIG.  39 C). Spreader  359  is able to slide from the closed indentation position because of the elasticity of torque levers  245 A- 245 B and the twist elasticity of spine rods  652 A- 652 B of spine  653 . 
     To close skeleton  950 , spreader  359  is slid along both torque levers from the open indentation position to the closed indentation position. Closure of skeleton  950  can seem slightly spring-loaded if preferred by utilizing the elasticity of torque levers  245 A- 245 B and twist elasticity of rods  652 A- 652 B of spine  653 ; to add the appearance of slight spring-loaded closure, pinholes  363 A- 363 B of spreader  359  are simply located a little closer to each other than their positions on a spreader  359  that just brings ring segments  46 A and  46 B of skeleton  950  into contact without stress. 
     FIGS. 40A-40B 
     FIGS. 40A-40B show perspective views of portions of a further preferred embodiment of a skeleton  1050  of the binder of the present invention. Skeleton  1050  comprises the same spine  653  as skeleton  650  shown in FIGS. 36A-36F, but incorporates a different middle ring  946  and has no torque levers and no spreaders. Skeleton  1050  has actuator  851 , which comprises rods  652 A and  652 B of spine  653  and interlocking ring  946  with ring sleeve  106 . Skeleton  1050  also has rings  46  near opposite ends of spine  653 , but are not shown in FIGS. 40A-40B. Ring sleeve  106  is springy and has inner protruding rim  106 A. Ring  946  has ring notches  107 A and  107 B near ring interlock  108 . When ring  946  is locked securely closed, ring sleeve  106  covers ring interlock  108  and is held in place by rim  106 A which is spring-biased to ring-closure notch  107 A. Sleeve  106  reinforces interlock  108 , which otherwise is prone to open accidentally during use. 
     To open skeleton  1050 , ring sleeve  106  is pulled away from notch  107 A and is slid along ring  946  away from interlock  108  until rim  106 A finds ring-open notch  107 B; then ring segments  946 A and  946 B are unhitched and pulled apart (FIG.  40 B). To close skeleton  1050 , ring segments  946 A and  946 B are hitched together creating interlock  108 ; then ring sleeve  106  is pulled away from ring-open notch  107 B and is slid along ring  946  toward interlock  108  until rim  106 A finds ring-closure notch  107 A. 
     Closure of rings  46  of skeleton  1050  can seem slightly spring-loaded if preferred by utilizing the elasticity of ring segments  946 A- 946 B, ring segments  46 A- 46 B, and twist elasticity of rods  652 A- 652 B of spine  653 . To add the appearance of slight spring-loaded closure, ring segments  946 A- 946 B and ring segments  46 A- 46 B should be attached to rods  652 A- 652 B, respectively, such that ring segments  946 A and  946 B are slightly open when ring segments  46 A and  46 B abut each other; when ring segments  946 A and  946 B are then forced together and locked close, rings  946 , rings  46 , and rods  652 A- 652 B will all be under elastic loading. 
     FIGS. 41A-41F 
     FIGS. 41A-41F show perspective and bottom views and a detailed sectional portion of a further preferred embodiment of a skeleton  1150  and its components of the binder of the present invention. Skeleton  1150  has rings  46 , spine  753 , and actuator  851 . Rings segments  46 A and  46 B are attached to rods  752 A and  752 B, respectively, via weld, braze, casting, or other appropriate means. Cleats  109 A and  109 B are attached to the backs of rods  752 A and  752 B, respectively. Spine  753  is formed by assembling rod  752 A alongside rod  752 B within wrap bands  141  and with cleats  109 A interspaced with cleats  109 B. Both the snug placement of bands  141  between pairs of rings  46  as well as the snug interspacing of cleats  109 A with  109 B prevent the longitudinal motion of rod  752 A relative to rod  752 B. Cleats  109 A and  109 B are attached to rods  752 A and  752 B along edges  752 C and  752 D, respectively, to facilitate pivot motion between rods  752 A and  752 B. When spine  753  is assembled, rods  752 A and  752 B pivot in opposite directions about contacting edges  752 C and  752 D through a limited angle to open or close ring segments  46 A relative to ring segments  46 B. The transverse cross-section of rods  752 A and  752 B (excluding cleats  109 A- 109 B) are shaped like a slice of pie having an obtuse angle (FIG.  41 E). The pie-slice cross-sections of rods  752 A and  752 B and the short-length of cleats  109 A- 109 B enable this pivot motion to occur within a cylindrical space, the obtuse-angle point of each pie-slice cross-section corresponding to edges  752 C and  752 D, respectively. 
     Torque levers  345 A and  345 B are integrally formed with or are attached to the ends of rods  752 A and  752 B preferably by casting, but may be attached by weld, braze, or other appropriate means. To facilitate the preferred casting of the whole component of skeleton  1150  shown in FIG. 41B as well as the whole component of skeleton  1150  shown in FIG. 41C using only one mold, torque lever  345 A is attached to the bottom of rod  752 A and the top of rod  752 B, and torque lever  345 B is attached to the bottom of rod  752 B and the top of rod  752 A. Torque levers  345 A and  345 B have protruding knobs  345 C and  345 D, respectively, which are connected by tensile spring  83 . Push levers  87 A and  87 B are integrally formed with torque levers  345 A and  345 B, respectively. Spring-metal ratchet pawl  105  is attached to push lever  87 A and engages push lever  87 B when push levers  87 A and  87 B are pivoted through a particular angle. Extendable capsule  385  hides spring  83  and has capsule segments  385 A- 385 B. Capsule segments  385 A and  385 B are integrally formed with torque levers  345 A and  345 B, respectively. 
     FIGS. 41E-F shows bottom views of skeleton  1150 . Actuator  851  comprises rods  752 A and  752 B, torque levers  345 A and  345 B, spreader  459 , and push levers  87 A and  87 B. In this embodiment of a skeleton  1150 , rods  752 A and  752 B serve as the first and second connective elements, respectively, of actuator  851 . Spring-loaded spreader  459  comprises spring  83 , ratchet pawl  105 , and push levers  87 A- 87 B and locks rings open when pawl  105  of push lever  87 A engages push lever  87 B. Tensile spring  83  is always under tension upon assembly of skeleton  1150 . 
     To open skeleton  1150 , push levers  87 A and  87 B are pushed together against the resistance of spring  83  until ratchet pawls  105  engage push levers  87 B, meanwhile rods  752 A and  752 B pivot in opposite directions to open rings  46 . Upon engagement, ratchet pawls  105  resists the closure of skeleton  1150  by spring  83  (FIG.  41 F). 
     To close skeleton  1150 , the free ends of ratchet pawls  105  are lifted away from push levers  87 B to disengage them, allowing spring  83  to act on torque levers  345 A and  345 B to pivot rods  752 A and  752 B until ring segments  46 A abut ring segments  46 B (FIG.  41 E). Rings  46  then remain closed because of the tensile loading of springs  83 . 
     FIG. 42 
     FIG. 42 shows a sectional view of a further preferred embodiment of a spine  853  of the binder of the present invention with rings  46  attached. Spine  853  has interlocking rods  852 A and  852 B, which do not require a wrapping band or housing to be assembled, but are joined together in puzzle-link fashion. Rod  852 A has a cross-section of a partial hollow cylinder, having a longitudinal opening  104  extending the length of rod  852 A and which receives a partly cylindrical portion of rod  852 B. Rod  852 B has a cross-section with a partly circular portion that when extended longitudinally is the partly cylindrical portion of rod  852 B, which is inserted into rod  852 A. A portion of rod  852 B protrudes into longitudinal opening  104  enabling rod  852 B to be stronger than if it were only a cylindrical rod because of its relatively larger cross-sectional area, which is roughly shaped like a short old-fashioned keyhole. The width or span of the longitudinal opening  104  of rod  852 A is smaller than the diameter of the partly cylindrical portion of rod  852 B; therefore, rod  852 B is inserted into rod  852 A either by snapping it in transversely, or by sliding it in longitudinally from one end. Rods  852 A and  852 B are constrained from moving longitudinally relative to one another by some means but can pivot through a limited angle relative to each other to enable the opening and closing of ring segments  46 A relative to ring segments  46 B. Since rods  852 A and  852 B cannot move longitudinally relative to each other, ring segments  46 A and  46 B of ring  46  open and close transversely relative to spine  853 . 
     FIGS. 43A-43B 
     FIGS. 43A-43B show bottom views with a detailed sectional portion of a further preferred embodiment of a skeleton  1250  of the binder of the present invention. Ring segments  46 A and  46 B and cleats  109 A and  109 B are attached to rods  952 A and  952 B, respectively. Rods  952 A and  952 B have longitudinal clefts  110 A and  110 B, which receive opposite edges of sheet-metal arc-spring housing  43 . Spine  953  is formed by assembling rod  952 A alongside rod  952 B within arc-spring housing  43  and with cleats  109 A interspaced with cleats  109 B. Rod  952 A and  952 B can pivot about contacting edges  952 C and  952 D upon assembly of spine  953 . Arc-spring housing  43  exerts a compressive force on clefts  110 A and  110 B. When edges  952 C and  952 D are within the perimeter of arc-spring housing  43 , this compressive force acts to keep rings  46  closed (FIG. 43A) and when edges  952 C and  952 D are outside the perimeter of arc-spring housing  43 , this compressive force acts to keep rings  46  open (FIG.  43 B). Rods  952 A and  952 B have roughly pie-slice-shaped cross-sections (excluding cleats  109 A- 109 B), which enables spine  953  to have a substantially cylindrical cross-section when rings  46  are closed (FIG.  43 A). Skeleton  1250  has actuator  951 , which comprises rods  952 A- 952 B and spring  43 . 
     To open skeleton  1250 , ring segments  46 A and  46 B are pulled apart against the compressive force of arc-spring housing  43  until edges  952 C and  952 D pivot beyond the perimeter of the arc-spring housing  43  at which point the compressive force begins to open the rings. Rings  46  continue opening until cleats  109 A and  109 B abut rods  952 B and  952 A respectively. To close skeleton  1250 , ring segments  46 A and  46 B are pushed together until they abut each other and then kept closed by the compressive force of arc-spring housing  43 . Optional torque levers with spring-loaded spreaders can be added to skeleton  1250  to increase the robustness of the closure force. 
     FIG. 44 
     FIG. 44 shows a bottom view of a further preferred embodiment of a ring  1046  of the binder of the present invention. Ring  1046  comprises ring segments  1046 A- 1046 B and the portion of spine  53  intersected by ring segments  1046 A- 1046 B. Ring segments  1046 A and  1046 B have varying prong thickness. Ring  1046  defines upright-ring diameter  111  which is the diameter that passes through the center of ring  1046  and the center of spine  53 . The portions of ring segments  1046 A- 1046 B that are roughly parallel to diameter  111  are thinner than the portions of rings segments  1046 A- 1046 B that are roughly perpendicular to diameter  111 . Consequently, the inner diameter of ring  1046  that is parallel to diameter  111  is less than the inner diameter that is perpendicular to diameter  111 . This variable prong thickness enables a more stable loose-leaf ring capacity during usage when the binder may be closed, opened  180  degrees, or opened 360 degrees. This variable prong thickness stabilizes capacity by compensating for the reduction in capacity otherwise caused by the existence of the spine  53  within the ring perimeter when the binder is open 360 degrees. 
     FIGS. 45A-45C 
     FIG. 45A shows a perspective view of a further preferred embodiment of a skeleton  1350  of the binder of the present invention. FIGS. 45B-45C are bottom views of Binder  1  of FIGS.  1 A- 1 L, with skeleton  1350  substituted in place of skeleton  50 . Skeleton  1350  uses the same rods  652 A- 652 B of spine  653  described with FIGS. 36A-36F and the spreader  259  described with FIGS. 38A-38C. Skeleton  1350  has rings  1146 , spine  1053 , and actuator  1051 . Ring segments  1146 A and  1146 B are attached to rods  652 A and  652 B, respectively, via weld, braze, casting, or other appropriate means. Likewise, intra-ring torque levers  445 A and  445 B are integrally formed with or are attached to the spine-end of ring segments  1146 A and  1146 B, respectively. Intra-ring torque levers  445 A- 445 B exist within both the plane and perimeter of the ring segments  1146 A- 1146 B to which they are attached. Although torque levers  445 A- 445 B are integrally formed with the ends of ring segments  1146 A- 1146 B, respectively, at the intersection with spine  1053 , torque levers  445 A- 445 B are distinguishable from ring segments  1146 A- 1146 B in that loose-leaves  72  are prevented from hanging off of torque levers  445 A- 445 B by spine  1053 . Rings  1146  comprise rings segments  1146 A and  1146 B and the portion of spine  1053  that is intersected, and excludes torque levers  445 A and  445 B. Spine  1053  is formed by assembling rod  652 A alongside rod  652 B within wrap bands  241 , which are snugly fitted between pairs of rings  1146 . Rods  652 A and  652 B rotate adjacent to each other in opposite directions through a limited angle to open and close ring segments  1146 A relative to ring segments  1146 B of rings  1146 . The snug placement of bands  241  between pairs of rings  1146  prevent the longitudinal motion of rod  652 A relative to rod  652 B. Actuator  1051  comprises rods  652 A- 652 B, torque levers  445 A- 445 B, and spreader  259 . Spreader  259  connects middle torque levers  445 A and  445 B and springs  83  connect the torque levers  445 A and  445 B that are located near opposite ends of spine  1053 . Spreader  259  is attached to skeleton  1350  via pins  102 A- 102 B, which are inserted within holes  463 A- 463 B, respectively, of torque lever  445 A (FIG.  45 B). Rings segments  1146 A and  1146 B have margin ring segments  1146 C and  1146 D, respectively. The purpose of margin ring segments  1146 C and  1146 D is to accommodate the margin of ring-bound loose-leaves  72  between the loose-leaf holes and adjacent loose-leaf edge during usage (FIGS.  45 B- 45 C). FIGS. 45B-45C show skeleton  1350  inserted within back cover  40  of cover  100  with front cover  44  flipped 360 degrees from its closed cover position. 
     Skeleton  1350  is operated in the same manner as skeleton  850  of FIGS. 38A-38C, which also has spreader  259 . 
     Skeleton embodiments  650 ,  750 ,  850 ,  950 ,  1050 ,  1150 ,  1250  and  1350  can be used in place of skeleton embodiment 50 in each and every of the preferred embodiments that incorporate skeleton  50  of the present invention via a small modification to the covers to accommodate torque lever pairs  45 A- 45 B,  145 A- 145 B,  245 A- 245 B,  345 A- 345 B,  445 A- 445 B, spreaders  59 ,  159 ,  259 ,  359 ,  459  and/or push levers  87 A and  87 B, which are more broadly categorized as actuator levers. Only a small modification is needed because the torque lever, spreader, and actuator lever embodiments of the present invention remain in the longitudinally projected perimeter of their associated ring embodiments as seen in FIGS. 36E,  37 C,  38 B,  39 B,  41 E, and  45 B. Therefore, the various means employed by the cover embodiments of the present invention to accommodate rotation of the rings about an edge of the flatly folded covers can be used to accommodate rotation of the torque levers, spreaders, and actuator levers. For example, this modification can be simply a transverse slot or equivalent means that is incorporated into the covers of the respective embodiments of the binders of the present invention such as slots  58 A- 58 C of FIG. 1A or holes  74 C- 74 D of FIG.  20 A. Furthermore, transverse opening of rings and transverse spreading of torque levers during use enable cover slots such as cover slots  58 A- 58 C of FIG. 1A to be narrow. 
     Intra-ring torque levers  445 A- 445 B of skeleton  1350  exist within both the plane and perimeter of the ring segments  1146 A- 1146 B to which they are attached. Consequently, skeleton  1350  can be used in all of the cover embodiments of the binder of the present invention that use slots to avoid cover interference with ring rotation when these cover embodiments are open 360 degrees (FIGS. 1A-1F, FIGS.  19 A- 19 C), but not with some cover embodiments (unless modified) that use cover holes (FIGS.  20 A- 20 C). 
     While my above descriptions contain many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of several preferred embodiments thereof. Many other variations are possible. For example, although spring-loaded spreaders have been shown with tensile springs, spreaders and torque levers can be adapted and possibly other parts added to use other springs such as compression, torsion, spiral, and sheet-metal springs. Rubber bands may also be substituted for tensile springs. Another possible embodiment of a spreader comprises a toggle switch and tensile spring. Spreaders and actuator levers with longitudinally oriented components that connect the transversely oriented intra-ring torque levers of skeleton  1350  can be incorporated, but these longitudinally oriented components must be positioned high enough within the rings away from the spine so as to clear the near-ring edge of the flat formation of various cover embodiments when the rings are rotated about the near-ring edge. Another possible embodiment of a pair of torque levers is a pair of interlocking torque levers; the interlocking means of such torque levers may or may not be spring-loaded. 
     It will appreciated by persons skilled in the art that herein described is a loose-leaf binder and analogous products and method of use. While the present invention has been described by reference to various preferred embodiments, it will be understood by persons skilled in the art that many modifications and variations may be made in those preferred embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that the invention not be limited to the disclosed preferred embodiments and that it have the full scope permitted by the following claims.