US 3566522 A
Description (OCR text may contain errors)
March 2,1971 I H- ETAL INDEX TABS Filed Jan. 28, 1969 1 I 5. W x; xx M W41 W, 1 m W 7 I a 4 United States Patent 3,566,522 INDEX TABS Thomas A. Leach, Mount Prospect, Joseph E. Kohnke, Arlington Heights, and Vernon J. Wiherg, Des Plaines, IlL, assignors to G. J. Aigner Company, Chicago, Ill.
Filed Jan. 28, 1969, Ser. No. 794,620 Int. Cl. G09f 3/16 US. C]. 40-23 7 Claims ABSTRACT OF THE DISCLOSURE An index tab is made of transparent plastic and can be positioned accurately at the edge of a sheet before adhesive of the tab is exposed to the sheet. Conventional use of moisturizing adhesives is eliminated by substituting a pressure sensitive adhesive and cooperating adherent protective strips. The strips are removed after the tab has been located in position.
This invention relates to index tabs, and more particularly to index tabs that can be positioned onto a sheet of paper or the like before any adhesive on the tab is in contact with the paper.
Index tabs are commonly made of a tabbing adapted to receive an informational insert, a skirt bonded to the edge of the tabbing, and an adhesive layer on the inside of the skirt. Usually the tabbing is transparent plastic, the skirt is cloth or similar flexible material, and the adhesive is moisturizable. Although index tabs of this general type are in wide use, they have well recognized limitations.
The fact of the adhesive being moisturizable gives rise to several problems. Since moisture must be applied before the tab is located on the edge of a sheet of paper, it is difiicult to locate the tab accurately without premature contact of the paper and adhesive, with consequent misalignment of the tab. Accordingly, a major object of the invention is to provide an index tab which can be positioned on the edge of a sheet of paper or the like before the adhesive is exposed to the paper.
Another disadvantage of existing moisturizable adhesive tabs arises from the inherent lack of sanitation. Common observation shows that most persons applying an index tab will moisten the adhesive with their tongues, either assuming that the adhesive is sanitary or else disregarding the possibility of contamination. A serious health hazard may exist when a clerk re-moistens a tab previously applied by another person which, quite apart from aesthetic objection, may harbor viable micro-organisms. A further object of the invention is to provide an index tab which avoids sanitary'difiiculties by eliminating the moisturized adhesive.
Further, in many common types of index tabs, the skirt is opaque. As a consequence, the skirt obscures informa tion located near the edge of the sheet. An additional feature of the invention is to provide an index tab having a transparent skirt.
Additional objects of the invention include the provision of a sturdy index tab featuring simple and economic fabrication, easy application and durability in use. Other objects will become apparent as the description of the invention proceeds.
Briefly, in accordance with the invention, there is provided an index tab having an insert-receiving tabbing member formed of a folded sheet of transparent plastic, a flexible skirt member formed of a second folded sheet of transparent plastic and laminated at its folded portion to the inner edge of the tabbing member, pressure sensitive adhesive layers on each of the inner edge portions of the skirt member, and a relatively stiff adherent strip member over each layer of adhesive. Thus, sheathing the edge of a 3,566,522 Patented Mar. 2, 1971 sheet of paper or the like with an index tab according to the invention permits the tab to be positioned accurately before the adhesive is exposed to the paper, and merely curling the edge portions of the skirt member away from the paper causes the strip members to peel off, thereby presenting freshly exposed adhesive to the paper.
In keeping with the invention, at least the skirt, and preferably both the tabbing and the skirt, are fabricated of polyethylene terephthalate (Mylar), the skirt plastic being advantageously from about one to about three mils thick and the tabbing plastic being about three to about five mils thick. Thus, full advantage is taken of the exceptional durability of polyethylene terephthalate, while at the same time there is no inordinate increase in manufacturing or fabrication cost as compared with conventional tabs.
As will appear subsequently, index tabs according to the invention can be fabricated readily in continuous automatic equipment. Thus, not only are the present index tabs superior in many functional respects to heretofore existing tabs, but they may be manufactured readily without elaborate equipment.
While the invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention thereto, but rather to cover all modifications and alternative constructions falling within the spirit and scope of the invention as broadly defined. The invention will be further described in conjunction with the appended drawings wherein:
FIG. 1 is a perspective of an index tab according to the invention, showing the tab in an uncut form;
FIG. 2 shows the placement of an index tab according to FIG. 1 saddle-wise on a sheet of paper or the like;
FIG. 3 is an enlarged view taken along 33 of FIG. 2, showing an end view of the index tab;
FIG. 4 shows the second step in applying an index tab, namely curling the skirt edges outwardly of the paper;
FIG. 4a continues FIG. 4, and illustrates the peeling or rolling-off action of the adherent strip so as to expose the adhesive; and
FIG. 5 depicts the index tab as attached to the sheet of paper.
Turning first to FIG. 1, the index tab 11 is depicted as an elongated stick or strip, which is to be cut to a desired size 14 along a schematic dotted line 12. (For simplicity, the individual lengths will continue to be referred to as the index tab 11.)
As best shown in the enlarged end view of FIG. 3, the index tab 11 is best fabricated of several parts, namely an insert-receiving plastic tabbing or tabbing member 15, a flexible plastic skirt or skirt member 16, pressure sensitive adhesive layers 18, and adherent strips or strip members.
The tabbing member 15 is formed of a folded sheet, in strip or web form, of a transparent plastic sheet. Advantageously, the plastic is polyethylene terephthalate, commonly known by the trademark Mylar, and supplied in various grades by the Du Pont Company. In the embodiment illustrated, the web from which the tabbing 15 is formed is about 1% inches wide, 4 mils thick, and is furnished in roll form. This Web material is sufiiciently thick to provide physical protection for a paper or paperlike insert 20 (see FIG. 5), and to this end is desirably at least about 3 mils thick. Thicknesses in excess of about 5 mils are generally unnecessary and unduly costly.
The tabbing 15 is transparent, and preferably is colorless. It may however be pigmented by the manufacturer of the plastic or of the tab so as to facilitate indexing. Generally however, it will be more convenient to provide a colorless tabbing 15 and, where colored indexing is desired, a colored paper insert 20 (FIG. 5)
The skirt 16 is likewise of a transparent plastic, and again is preferably polyethylene terephthalate. Since it is preferable that the skirt 16 be more flexible than the tabbing 15, polyethylene terephthalate with its exceptional tensile strength, flexibility, and physical durability is presently the material of choice. In the embodiment shown in 'FIG. 3, the skirt 16 is folded from a sheet or web of polyethylene terephthalate one inch wide by 1.5 mils thick. Its thickness may, in appropriate circumstances, be as little as about 1 mil or as much as about 3 mils, with the thinner skirts being somewhat more fragile while thicker skirts tending to be somewhat stiffer than is considered optimum for index tabs of this type.
As seen from FIG. 3 and, in perspective in FIG. the index tab has the skirt 16 laminated to the tabbing 15 at the fold portion 21 of the skirt 16. The respective folds of the tabbing 15 and the skirt 16 are parallel to each other, so that the edge portions 22 extend uniformly from the tabbing member .15. Thus, as may be seen from FIG. 2, the saddle-wise sheathing of an index tab 11 along the edge of a paper sheet 24 aligns the tabbing 15 parallel to the edge of the paper 24.
In further keeping with the invention, and with particular reference to FIG. 3, an adhesive layer 18 is on each of the inner extending edge portions 22 of the skirt 16. These layers 18 extend longitudinally along the edge portions 22, and preferably terminate just short of the ends 24 of the edge portions 22. Similarly, the adhesive layer 18 preferably does not extend to the laminated region 21 where the skirt 16 is bonded to the tabbing 15, for reasons which will be apparent in subsequent discussion.
Covering the facing sides of the adhesive layers 18 is an abherent or strip member 19, one strip 19 adjacent each adhesive layer 18. These strips 19 are preferably composed of a paper or paper-like material that is stiffer than the plastic of the skirt 16, and which is coated with an abherent to facilitate its removal from the pressure sensitive adhesive 18. A variety of abherents is known (see Kirk and Othmer, Encyclopedia of Chemical Technology, Second Edition, volume 1, Abherents, pages l-ll), although the methyl silicone polymers are preferred.
The strips 19 are each about A inch wide, and extend longitudinally of the index tabs 11 (see FIG. 2). Abherent strips 19 precoated with a pressure sensitive adhesive (for adhesive layer 18) are available commercially in rolled web form, and are coated with two different abherents, one more effective than the other. A pressure sensitive adhesive is coated by the manufacturer on the less effective side of the web. Thus, an adhesive coated abherent web can be rolled up into coil form, and when it is uncoiled the more effective abherent side peels oif from the adhesive, leaving the adhesive on the less abherent coated side of the strip.
Pressure sensitive adhesives are likewise well known. (See Kirk and Othmer, cited volume, volume 1, pages 371-405.) These are normally tacky, natural or synthetic materials having a cohesive strength greater than their adhesive strength. The preferred pressure sensitive adhesive is a film forming styrene-butadiene copolymer rubber of a high Mooney value blended with hydrogenated esters of wood rosin and applied from a tolueneheptane solvent system, One such material is Kleen Stik high tack D Transfer Tape, made by Kleen Stik Products division of Compac Corp., 420 Frelinghuysen Ave., Newark, NJ.
For laminating the tabbing 15 to the skirt 16, a heat and pressure bonding adhesive is preferred. This adhesive advantageously is a polyester resin in a volatile halocarbon solvent, together with optional hardeners and the like. It likewise should be transparent and as colorless as possible. Suitable polyester adhesives are described in Adhesives for Du Pont Mylar Polyester Film, published by E. I. du Pont de Nemours & Co.,
4 as Bulletin No. 17, August 1961, sixth edition, and subsequent editions thereof.
To manufacture the index tabs 11 of the invention, relatively simple modification of conventional continuous index tab equipment may be employed. Automatic equipment is advantageously used. Thus, in sequence, the following steps are carried out:
(1) Withdraw from coils a pair of abherent webs constituting strips 19 and containing, on each strip 19, a layer of normally tacky and pressure sensitive adhesive 18;
(2) Apply one such strip 19 onto a web constituting skirt 16 in unfolded form, adhesive side toward the skirt 16;
(3) Fold the web of skirt 16 at about its center line, using a continuous mandrel, with the strips 19 facing inwardly;
(4) Apply heat sensitive polyester adhesive to the edge portions 21 of the web of tabbing material as the first step in making tabbing member 15;
(5) Make a preliminary center fold of the tabbing 15 into a generally V shape with the adhesive-coated portions inward; i bet] (6) Position the folded web of skirt 16 into place between the V of the tabbing material 15;
(7) Apply heat and pressure to the edge portions 21 of the tabbing member 15 so as to adhesively laminate the two together;
(8) Pass the assembly through a heated forming die at about 260 F, to form the beaded portion 25 at the fold line of tabing 15 (a wire mandrel is used to expand the beaded portion while in the die);
(9) Optionally apply further pressure to bond the tabbing 15 to the skirt 16;
(10) Cool the assembled tabbing; and
(11) Cut to size.
The foregoing operations, as indicated earlier, are best performed automatically and continuously. The resulting product is shown in FIG. 1, and is conventionally about six inches long. The index tabs 11 may then be packaged into suitable containers, either manually or automatically.
Application of an index tab 11 to a sheet of paper or the like 24 is best shown in sequence FIG. 2, FIG. 4, FIG. 4a and FIG. 5. Inviting attention to these figures:
FIG. 2 illustrates the first step of applying an index tab 11 to the paper 24. After cutting the tab 11 to desired size, and with the abherent strips 19 in place, the tab 11 is placed saddle-wise along the sheet of paper 24 in any desired position. Since no adhesion is in contact with the paper, the tab can be positioned accurately at this stage, in contrast to conventional moisturable adhesive index [tabs which, once placed, are in position whether corrected or not.
FIG. 4 shows the next step. With the thumb or another finger, the edge porttions 22.of the skirt 16 are lifted upwardly and curled outwardly away from the sheet 24. Since the strips 19 are abherent, and are stiffer than the plastic of skirt 16, they tend to curl or peel away from the skirt 1 6, as shown in FIG. 4 and, in a more advanced stage, in FIG. 4a. It will be apparent, therefore, that with slight pressure on the bead 25 of the index tab 11, the tab is maintained immovable, while the abherent strips 19 are rolled oil and away from the skirt 16.
As the last step in applying the present index tabs 11, it is merely necessary to apply slight pressure to the edge portions 22 of the skirt 16, as shown in FIG. 5. This bonds the tab 11 to the sheet of paper or the like 24. If, as is preferred, the adhesive layer 18 (FIG. 3) terminates just short of the end 24 of the skirt 16, removal of tab 11 is facilitated merely by inserting a knife blade or a fingernail under the end 24 and lifting the edge portions 22 away from the paper 24.
After installing the index tab 11, a paper or similar insert 20 may he slipped into the insert-receiving spacedapart aperture 26 (as best shown in FIG. 3). The insert 20 beats indicia serving to identify materials filed behind the paper 24.
Thus it is apparent that there has been provided, according to the invention, an improved index tab that fully satisfies the objects of the invention. Not only may it be fabricated readily, but its virtues become evident when comparing its use With conventional moisturizable adhesive tabs.
1. In an index tab for attachment to the edge of a sheet of paper or the like, and having:
( 1) an insert-receiving tabbing member formed of a folded sheet of transparent plastic,
(2) a flexible skirt member formed of a folded sheet of transparent plastic,
(a) said skirt member being laminated at its fold portion to the inner edge portions of said tabbing member,
(b) with the respective folds parallel to each other,
(c) and with edge portions of said skirt member extending from said tabbing member, and
(3) a layer of adhesive on each of the extending edge portions of said skirt member,
the improvement wherein said index tab can be positioned on the edge of said sheet of paper or the like before the adhesive is exposed to the paper, comprising:
a normally tacky and pressure sensitive adhesive as the layer of adhesive on each of the inner extending edge portions of said skirt member, and
a removable adherent strip member over each layer of adhesive,
(a) said strip member being stifier than the plastic of said skirt member,
(b) so that outwardly curling the edge portions of said skirt member peels said strip members after said index tab is positioned and thereby presents said layers of adhesive to said sheet of paper or the like.
2. The tab of claim 1 wherein the plastic of said skirt member is polyethylene terephthalate.
3. Tab of claim 1 wherein both of said plastics are polyethylene terephthalate.
4. Tab of claim 1 wherein the plastic of said tabbing member is about three to five mils thick.
5. Tab of claim 1 wherein the plastic of said skirt member is about one to three mils thick.
6. Tab of claim 1 or 5 wherein said strip member is a silicone coated paper.
7. A method of applying an index tab to a sheet of paper or the like comprising:
(1) sheathing the edge of said sheet with an index tab having a flexible skirt member, a layer of normally tacky and pressure sensitive adhesive on each of the inner edge portions of said skirt member, and a relatively stiifer abherent strip member over each layer of adhesive,
(2) outwardly curling the edge portions of said skirt member so that said strip members peel from said adhesive,
(3) and pressing the edge portions of said skirt member so that said index tab is adhesively secured to said sheet.
References Cited UNITED STATES PATENTS 1,961,079 5/1934 Pettis -2 2,246,984 6/ 1941 Palmer 40-2 3,054,202 9/ 1962 Scholfield 40-2 FOREIGN PATENTS 620,200 5/1961 Italy 40-164 ROBERT W. MICHELL, Primary Examiner W. J. CONTRERAS, Assistant Examiner Patent No.
PCP-1050 Dated March 2, 197].
Inventor(s) Thomas A. Leach, Joseph E. Kohnke, Vernon J. Wiberg It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
' Abstract, Line 16 C01. 1, Line 71 C01. 2, Line 39 C01. 2, Line 52 C01. 5, Line 31 Signed and sealed (SEAL) Attest:
EDWARD M.FLETCHER,JR. Attesting Offlcer The word adherent should be changez to read abherent.
The word adherent should be changec to read abherent.
The word adherent should bechangec to read abherent.
The word adherent should be changed to read abherent.
The word adherent Should be changed to read abherent.
this 21st day of March 1972.
ROBERT GOTTSCHALK Commissioner of Pat