This invention relates to looseleaf binder sheets, and more particularly to looseleaf binder sheets having the capability of being both securely retained in the binder from removal in response to forces acting in one direction, while also being easily removed against the binder when withdrawn in an alternate direction.

BACKGROUND ART 
Due to the flexibility provided by looseleaf binders, such binders and 
replacement sheets for these binders have become very popular for both 
school and business use. However, although looseleaf binders and looseleaf 
binder sheets have existed for many years, one problem that has remained 
unsolved is the inability of the looseleaf binder sheets to be both 
securely retained in the binder, while also being easily removed and 
subsequently reinserted without causing any ripping or tearing of the 
sheet of paper and without having to open the binder. 
Although the desire to remove and replace individual sheets of paper in 
looseleaf binders without opening the binder and without tearing the edges 
of the sheet has always existed, the requirement that the looseleaf sheets 
be securely retained has been the dominant objective to which prior art 
patents have been directed. As a result, these prior art inventions and 
products teach reinforcing tabs, inserts, or liners, all of which are 
constructed to enhance the strength of the looseleaf sheet of paper in the 
area about the binder-receiving holes, in order to assure secure retention 
of the sheets by the binding posts or rings. Such systems are taught in 
U.S. Pat. Nos. 915,789 and 3,315,683. However, these prior art systems do 
not enable the user to remove any sheet from the binder without either 
opening the binder or ripping the sheet. 
Consequently, the principal object of the present invention is to provide 
pre-punched sheets for looseleaf binders wherein each sheet is capable of 
being securely retained in the binder, free from accidental, unwanted 
dislodgement or removal, while also being freely removable from the binder 
without opening the binder and without permanently damaging the sheets of 
paper. 
Another object of the present invention is to provide sheets of looseleaf 
paper having the characteristic features described above which is capable 
of being removed quickly and easily as well as repeatedly, without causing 
any degradation of the holding system. 
Another object of the present invention is to provide sheets for looseleaf 
binders having the characteristic features described above which also 
incorporates edge reinforcements to further enhance the structural 
integrity and longevity of the dual-function sheets. 
Other and more specific objects will in part be obvious and will in part 
appear hereinafter. 
DISCLOSURE OF THE INVENTION 
With the present invention, the prior art drawbacks are all overcome and 
eliminated and a unique construction for looseleaf binder sheets is 
achieved. The looseleaf binder sheets of this invention incorporate at 
least two layers of sheet material about each fastening or 
binder-receiving hole of the paper sheets with each layer incorporating 
flexible, binder locking fingers between the side edge of the paper and 
each binder-receiving hole, thereby creating at least two flexible, 
overlying binder-locking fingers directly adjacent each binder-receiving 
hole. 
Furthermore, these overlying binder-locking fingers are constructed with 
their respective terminating ends offset from each other, thereby 
achieving a cooperating, overlapping, juxtaposed construction, which 
provides interlocking engagement of the sheet of paper in the binder to 
prevent withdrawal of the sheet from the binder in response to forces 
acting radially on the binder-receiving holes of the paper sheet or 
primarily in the plane of the sheet. However, when forces are applied to a 
paper sheet which forces are not in the plane of the sheet and, instead, 
are either acting axially to the binder-receiving holes or at an acute 
angle thereto, the flexible, binder-locking fingers are bent and displaced 
relative to each other, allowing the sheet of paper to be withdrawn from 
the binder, quickly and easily without permanently damaging the sheet of 
paper or requiring the binder to be opened. As a result, a dual-function 
looseleaf binder sheet is achieved. 
In the preferred embodiment, the paper sheet of the present invention 
incorporates a single elongated reinforcing strip which is securely 
fastened to the side edge of the sheet of paper, providing a twin layer 
reinforced area about each of the binder-receiving holes, while only 
requiring a single additional component. However, if desired, separate 
overlying reinforcing segments can be affixed about each binder-receiving 
hole in order to achieve the overlapping, flexible, binder-locking finger 
construction of the present invention. 
In the preferred embodiment, two overlying flexible, binder-locking fingers 
are employed and have been found to provide the desired secure retaining 
engagement with the binder in response to forces acting radially about the 
binder-receiving holes, as well as the desired quick and easy removal of 
the sheets in response to forces acting along the central axis of the 
binder-receiving holes or the forces at acute angles thereto. However, if 
desired, three or more layers could be employed without departing from the 
scope of this invention. 
The invention accordingly comprises an article manufactured possessing the 
features, properties and relation of elements which will be exemplified in 
the article hereinafter described, and the scope of the invention will be 
indicated in the claims.

BEST MODE FOR CARRYING OUT THE INVENTION 
In FIG. 1, the preferred embodiment of dual function, looseleaf binder 
sheet 20 of the present invention is shown. In this preferred embodiment, 
looseleaf binder sheet 20 comprises a conventionally-sized paper sheet 21 
having a side edge 25 and three binder-receiving holes 22 formed therein 
inwardly along side edge 25. In addition, dual function, looseleaf binder 
sheet 20 incorporates an elongated, continuous, reinforcing strip 23 
having a side edge 27 and three binder-receiving holes 24 formed therein 
inwardly of side edge 27. Also, paper sheet 21 incorporates a plurality of 
bonding zones 28 positioned between holes 22 for secure bonded engagement 
with reinforcing strip 23 when strip 23 is positioned in overlying 
engagement therewith. 
Paper sheet 21 also incorporates slits 30 which, in the embodiment shown in 
FIG. 1, extend radially from each binder-receiving hole 22 to side edge 25 
of paper sheet 21. As will be more fully described below, each slit 30 
establishes a flexible binder locking finger 31 between each 
binder-receiving hole 22 and terminating side edge 25. 
In a similar construction, elongated strip 23 incorporates slit 34 radially 
extending from each binder-receiving hole 24 to terminating side edge 27 
of strip 23. As with slits 30, slits 34 establish a flexible, 
binder-locking finger 35 between each binder-receiving hole 24 and edge 27 
of elongated strip 23. In the preferred construction shown in FIG. 1, each 
slit 34 joins side edge 27 at an acute angle thereto. Preferably, slits 34 
have a direction of slope which is opposite to the direction of slope of 
slits 30. In this way, binder-locking fingers 31 and 35 have terminating 
edges on opposite sides of binder-receiving holes 22 and 24 and are 
capable of being assembled into cooperating pairs having an interactive, 
overlapping construction. 
In order to complete the construction of the dual function, looseleaf 
binder sheet 20 of the present invention, strip 23 is securely bonded 
along the side edge of paper sheet 21 with binder-receiving holes 24 and 
22 being concentrically axially aligned. Although strip 23 can be bound to 
paper sheet 21 in a plurality of alternate constructions, it has been 
found that the use of fastening means such as glue positioned along the 
side edge of paper sheet 21 in fastening zones 28 between holes 22 
provides the desired secure affixation of strip 23 to paper sheet 21. 
Once strip 23 has been securely affixed to paper sheet 21, the construction 
of dual function, looseleaf binder sheet 20 of the present invention is 
completed. As is fully detailed below, the creation of two cooperating, 
juxtaposed, overlapping, flexible, binder locking fingers 31 and 35 
positioned between each of the aligned binder-receiving holes 22 and 24 on 
one side thereof, and the aligned terminating edges 25 and 27 on the other 
side thereof, looseleaf binder sheet 20 is achieved. With this 
construction, looseleaf binder sheet 20 is securely retained in a binder, 
preventing withdrawal thereof in response to forces acting in the plane of 
the sheet, while also being quickly and easily withdrawn from the binder, 
without ripping of the sheet or opening of the binder, in response to the 
forces acting substantially perpendicular to the plane of looseleaf binder 
sheet 20 or at an acute angle from these perpendicular forces. 
In FIGS. 2 and 3, two alternate embodiments of the present invention are 
shown. In these embodiments, elongated strip 23 and paper sheet 21 
incorporate alternate slit configurations. 
In FIG. 2, slits 34 of elongated strip 23 is depicted substantially 
perpendicular to side edge 27 and extending therefrom to binder-receiving 
holes 24 at a position almost tangential therewith. Similarly, slits 30 of 
sheet 21 extends substantially perpendicularly from side edge 25 of sheet 
21 to binder-receiving holes 22, which are concentrically aligned with 
holes 24 of strip 23, with each slit 30 joining concentrically aligned 
binder-receiving holes 22 of sheet 21 at a point substantially tangential 
to holes 22 and at a position opposite slit 34. In this way, flexible 
binder-locking fingers 31 are created on sheet 21 which are in juxtaposed 
underlying cooperating relationship with flexible binder locking fingers 
35 of strip 23. 
In FIG. 3, a similar dual-function, looseleaf binder sheet configuration is 
shown wherein slits 34 of elongated strip 23 extends substantially 
perpendicularly from edge 27 to binder-receiving holes 24, as described 
above in FIG. 2, while slits 30 of sheet 21 extends at a sloping angle 
between concentrically aligned binder-receiving holes 22 to terminating 
edge 25 in a substantially identical manner as described above in 
reference to FIG. 1. In this configuration, although the angles of slits 
30 and 34, in relationship to the side edges, are not substantially 
identical, an operatively identical construction is achieved with 
overlying, flexible, binder-locking fingers 35 and 31 being created in 
order to achieve the dual function locking and removal construction of 
this invention. 
By referring to FIGS. 1, 2 and 3, it is readily apparent that many 
alternate constructions and arrangements for the present invention can be 
employed without departing from the scope of this invention. In 
particular, any multi-layer configuration which achieves a plurality of 
juxtaposed, overlying, cooperating, flexible, binder-locking fingers 
positioned between the binder-receiving holes and the side edge of the 
looseleaf sheet would provide an operative looseleaf binder sheet 
incorporating this invention. 
In FIGS. 4-7, sequential views of the operation of the flexible 
binder-locking fingers are shown as the dual-function, looseleaf binder 
sheet 20 of the present invention is inserted onto a ring binder for 
secure retained engagement therewith. FIGS. 8-11 represent similar 
sequential insertion steps, with looseleaf binder sheet 20 viewed from an 
alternate position. In order to clearly depict the insertion and 
engagement process of the cooperating, overlapping, flexible, 
binder-locking fingers with a binder, FIGS. 4-11 depict the engagement 
operation of a section of looseleaf binder sheet 20 about a single ring 
binder 40. However, as is readily apparent from this description, the 
entire dual-function looseleaf binder sheet 20 of the present invention 
would be securely mounted to any fastener in an identical fashion 
regardless of the number of binder-receiving holes incorporated on the 
looseleaf sheet. 
In FIGS. 4 and 8, dual-function, looseleaf binder sheet 20 of the present 
invention is shown in its initial stages of mounting engagement with ring 
binder 40. As shown therein, as forces are applied to sheet 20 which are 
acting substantially coaxially with the central axis of concentrically 
aligned binder-receiving holes 22 and 24, or at acute angles thereto, 
overlapping flexible binder-locking fingers 35 and 31 begin to spread away 
from their respective finger forming slits 34 and 30. As additional force 
is applied, flexible binder locking fingers 31 and 35 continue to 
spreadingly disengage from their overlapping relationship until separated, 
as shown in FIGS. 5 and 9. 
Then, as shown in FIG. 6, the application of additional paper insertion 
force causes flexible binder-locking fingers 31 and 35 to slide over the 
surface of ring binder 40 moving from engagement with its outside diameter 
to engagement with its inside diameter, causing coaxially aligned 
binder-receiving holes 22 and 24 to peripherally surround binder ring 40. 
In FIG. 10, dual function, looseleaf binder sheet 20 is shown in the last 
stage prior to final completed engagement with ring binder 40, wherein 
flexible binder-locking finger 35 is depicted approaching complete 
overlapping juxtaposed cooperating engagement with underlying flexible 
binder locking finger 31, with binder locking finger 35 also approaching 
abutment with slit 34. 
In FIGS. 7 and 11, the dual function looseleaf binder sheet 20 of the 
present invention is shown in its fully engaged position with ring 
fastener 40, with FIG. 11 clearly depicting the secure retained engagement 
of sheet 20 with ring binder 40 when forces acting upon sheet 20 are 
imposed substantially coplanar with sheet 20. When any such coplanar 
forces are imposed upon sheet 20, the side edges of binder locking fingers 
35 and 31 directly abut the surface of binder 40, exerting a lateral force 
on binder-locking fingers 31 and 35. Since the flexibility inherent in 
binder-locking fingers 31 and 35 is in response to forces acting 
substantially perpendicular to fingers 31 and 35, fingers 31 and 35 remain 
stationary against these lateral forces, thereby securely retaining sheets 
20 in locked engagement with ring binder 40. In this way, the dual 
function of both locked engagement and quick and easy withdrawal of a 
looseleaf binder sheet 20 is achieved. 
It will thus be seen that the objects set forth above among those made 
apparent from the preceding description, are efficiently attained and, 
since certain changes may be made in the above article without departing 
from the scope of the invention, it is intended that all matter contained 
in the above description or shown in the accompanying drawings shall be 
interpreted as illustrative and not in a limiting sense. 
It is also to be understood that the following claims are intended to cover 
all of the generic and specific features of the invention herein 
described, and all statements of the scope of the invention which, as a 
matter of language, might be said to fall therebetween.