US2571525A - Method of binding sheet material in piles - Google Patents

Description

Oct. 16, 195] A, BLlTSTElN I 2,571,525

METHOD OF BINDING SHEET MATERIAL IN FILES Filed Jan. 29, 1948 Q $1 Ii thetic plastic material.

Patented Oct. 16, 1951 OFFICE METHOD OF BINDING SHEET MATERIAL IN FILES Arthur Blitstein, Chicago, Ill.

Application January 29, 1948, Serial No. 4,958

1 Claim. 1

The instant invention pertains generally to methods for binding sheet material in piles. More specifically, the instant invention pertains to an improved method of binding magazines, notebooks or the like with plastic or other heatsealable material to obtain a ring-like binding, as distinct from the sewn or stapled type of binding. The binding art has long been beset by the problem of achieving a ring-type binding which is permanent, yet easy to produce, soft and pliant, yet possessed of a tear strength which is greater than that of the bound sheets. By ringtype binding is meant that class of binding wherein a binding member is inserted through edge perforations adjacent an edge of the stack of sheets to be bound. In lieu of a binding possessing the foregoing desirable characteristics, however, the art has come to use either coarse fabric material or else rigid plastic materials which rely upon their inherent rigidity to hold the bound sheets together. As a binding material, rigid plastics have the drawbacks of lacking flexibility and of having a tendency to crack or split apart under hard usage. Also, they lack pliability. Because of their hardness, such materials are unpleasant to the touch, and tend to tear and abrade the paper through which they are threaded. Fabric, on the other hand, bein very flaccid, does not yield a binding having a uniform appearance unless stiffened by a filler.

Fabric also is characterized by a tendency to fray apart when used to bind heavy or rough sheets. In addition, the fabric binding member is ordinarily secured together by gluing, so that the binding operation requires clamping the portions together until the adhesive is set. Thus, binding with this type of material is slow and inefficient.

The instant invention, on the other hand, eliminates the foregoing disadvantages inherent to the prior art binding processes. Stated briefly, my novel process consists of binding a stack of sheets together by thermal welding of a binding blank formed from a flexible, tough synsteps is as follows: (1) the binding blank is chilled to impart sufiicient rigidity to facilitate insertion; (2) the binding fingers are inserted through perforations formed adjacent one edge of the stack of sheets; (3) the binding fingers are butted against the backing portion of the blank and (4) seam welded thereto.

My new method of binding may be practiced with relatively simple tools; however, if desired, it may be adapted to a semi or fully automatic A preferred sequence of i binding process. By using it, bindings for books and the like may be obtained which are attractive in appearance, capable of withstanding harsh treatment without any diminution of their utility, and inexpensive.

It is the principal object of my invention, therefore, to provide a binding method whereby a large number of sheets may be bound together permanently into a book or the like. v

Another object of my invention is to provide a method for manufacturing books or the like having a pliable, tough binding which is capable of withstanding harsh treatment.

Another object of my invention is to provide a method of binding notebooks, magazines or the like which is inexpensive and which may be reduced to automatically performed steps.

Another object of my invention is to provide a, method of manufacturing books wherein the binding appears to be a plurality of separate sealed ring-like members.

The foregoing and such other objects, principles, advantages and capabilities as are disclosed as this description proceeds, or which are inherent in the present invention, are illustrated in the accompanying drawing, in which:

Figure 1 is a perspective view of a preferred form of blank for practicing the instant invention;

Figures 2-4 illustrate successive steps in the preferred practice of my new method; Figure 2 being a plan View; and Figures 3 and 4 being side elevational views taken in section along the line 3-3 of Figure 2;

Figure 5 illustrates schematically one form of apparatus which may be used to fuse the blank together permanently;

Figure 6 is a plan view taken in vertical section through the bound volume;

Figure 7 is a fragmentary front elevational View of the binding shown in Figure 6; and

Figure 8 is a perspective view illustrating an intermediate step in an alternate binding method conforming to my invention.

Like reference characters designate like parts in the drawing and in the description thereof which follows.

Referring now to the drawings, and more particularly to Figure 1 thereof, the binding blank I6 is shown as having a comb-shaped configuration and comprising a rib H and a pluralityof outwardly extending binding fingers I2. While the blank if! is shown as having closely spaced fingers I2 of a more or less rectangular cross section, other configurations, as for example a blank having binding fingers of circular cross-section, are within the contemplated scope of my invention. Regardless of the particular form which it may take, the binding blank I is made of flexible, tough, heat-scalable material, such as thermoplastic synthetic resins derived from rubber hydrochloride, polyvinyl chloride, polyvinylidene chloride, polyethylene, or the like. Such materials are particularly advantageous as a binding medium since they are tough, coriaceous, possess some elasticity and pliability, and in addition may be obtained in myriad colors and surface patterns. Thus, binding formed with my method add to, rather than detract from, the attractive appearance of the bound volume.

III will be less than so that the binding fingers I2 normally possess little rigidity, particularly in the unbound condition due to the desirable flexible or flaccid character of the material. Consequently, to assist in inserting the finger I2 through the edge perforations provided,

it is desirable to either increase the rigidity of the fingers I2, or provide a suitable fixture for :guiding the fingers I2 through the perforations, or preferably use a combination of both of these 'expedients. One way of increasing the rigidity "of the fingers I2 is to reduce the amount of plasticizer used in manufacturing the plastic material until the desired rigidity is obtained, however,

this method has the drawback of increasing the rigidity permanently, and thereby making the final product too stiff. Advantageously, I have discovered that the rigidity of the binding fingers I2 may be increased temporarily by chilling the blank I0 b ordinary refrigeration methods. Obviously, however, the temperature of the blank II] should not be lowered to the point where the blank I0 becomes so brittle that there is an atapplications thereof. Moreover, this effect lasts for a sufficiently long period of time to permit reasonable delays in inserting the fingers I2 after chilling the blank I0, since heat scalable materials in general possess insulating characteristics, and thus exchange heat at a comparatively slow rate.

The initial step whereby the binding blank III is processed into a completed binding after being chilled is illustrated in Figures 2 and 3. The stack of sheets I3 which is to be bound into a book is shown as comprising two covers I4 and I5 and a plurality of interior sheets I6. A plurality of regularly spaced perforations H extend through the stack of sheets 13 adjacent one edge thereof, the spacing of the perforations I'I corresponding to that of the binding fingers I2. In practice it has been found advantageous to align the sheets I3 within a press or the like with 'the perforated edge section accessible for binding. Further advantages are realized by providing a flat surface which supports and guides the blank III as it is being inserted through the perforations II. By this latter expediency, in combination with the foregoing chilling operation,

the insertion of the blank I I] is greatly simplified.

V15 Ordinarily, the thickness of the binding blank After the binding material III has been inserted through the perforations H, the rib II and the binding fingers I2 are bent upward so that the blank I 0 in cross-section assumes a U-shaped configuration, as shown in Figure 4. Following this step, the outer free ends of the fingers I2 are butted against corresponding portions of the rib II. The cross-sectional appearance of the binding blank III at this state of the process is illustrated in Figure 5.

After the binding fingers I2 are butted against the rib II, they are permanently fused thereto. One exemplary method of fusing the fingers I2 to the rib I I is to use high frequency heat sealing apparatus such as that shown diagrammatically in Figure 5. Specifically, this apparatus includes an electric circuit I8 connected across two metallic plates I9, I9, which plates press against the abutted portions of the blank Ill. The electric circuit I8 in turn includes a source of high frequency current, as exemplified by the frequency converter unit 20, a control unit 2|, and a Variable resistance 22 shunted across one of the plates I9. The unit 2!] draws its energy from an electrical energy supply source (not shown). By experience, it has been found practical to include in the control unit 2| an ammeter 23, an adjustable timer element 24, and a switch 25 operatively connected through the timer element 24. Thus, upon closing the switch 25, a controlled high frequency current fiows from the converter unit 20 to the metallic plates I9, I9 for a predetermined interval.

Inasmuch as thermoplastics in general possess good dielectric properties, the passage of a high frequency current therethrough quickly fuses the contacted surfaces of the blank I0 together. Because the dielectric characteristics of the binding are dependent principally on the type of material being fused and the thickness thereof, it becomes necessary, when different materials and different thicknesses are to be processed with one set of apparatus, to provide means for adjusting both the magnitude of the current and the time interval during which said current flows. This is accomplished by means of the variable resistance 22 and the timer element 24. By varying the variable resistance 22, the intensity of current flowing across the binding may be altered, while the timer element 24 may be adjusted to give the desired time interval during which this current is to flow.

Advantageously, the foregoing sealing operation in no way affects the surface of the blank If) adjacent to the plates I9, I9, all fusion of the material occurring at the interface. This apparently stems from the fact that in electronic heat sealing the heat flow is from the inside of the material to the outer surfaces thereof. In addition, the plates I9, I9 rapidly conduct heat away from the adjoining surfaces of the blank I0, as a consequence of which the sealed binding blank I0 is cold to the touch when removed from be tween the plates I9, I9.

Obviously, other types of apparatus for sealing the binding material together may also be used to advantage. Thus, for example, it may prove advantageous to dispense with the electronic heating apparatus shown in Figure 5 and employ low frequency seam welding in its place. Again, in some instances, it is desirable to merely heat the plates I9, I9 to a temperature which is sufficient to melt or make sticky the binding material used, the welding temperature ordinarily being between F. and 300 F., depending upon the particular material selected. This mode of sealing proves particularly useful where the melting point of the binding material being used falls within the lower portion of this temperature range.

The appearance of the completed binding is shown in Figure 6. It will be noted that subsequent to the sealing operation, the cover I4 is rotated through a full revolution. Hence, the portions of the binding blank I which are fused together are contained entirely within the cover sheets [4 and I5 of the bound volume. In Figure 6, the sealed portion of the blank ll) appears to be of prominent size, because the proportions have been exaggerated somewhat for purposes of clarity. Actually, the thickness of the sealed portion in no way interferes with the closing of the cover sheet [4. The appearance of the completed one-piece binding taken in front elevation is shown in Figure 7, wherein the ring-like effect of the completed binding is apparent.

Besides acting as a common support for the tabs I2, the rib II also serves to reinforce the flexure strength of the bound volume. In the event that it becomes desirable to provide a binding consisting of separate ring like bindings, however, this form of binding may also be achieved through the use of my novel method. In that case, the outer free ends of the binding fingers [2 are butted against the inner end portions thereof, as shown in Figure 8, rather than against the rib H, after which the abutted surfaces are welded together. Individual ring bindings are then obtained by cutting each binding finger l2 along the dotted line 26.

By means of my invention, then, it becomes possible to obtain bindings of novel and varied characteristics. For example, the strength, flexibility and elasticity of the binding may be controlled by varying the thickness of the blank [9. Again, as emphasized above, heat-scalable materials are available in many different surface textures and colors. By Way of example, bindings may be obtained which closely simulate leather or fabric.

Thus, it will be seen that the objects of my invention have been fully achieved. While I have shown and described a preferred method of practicing my invention, it is strictly to be understood that this method has been given by way of example only, and that various changes and variations in the steps shown and described herein may be made Without departing from the spirit of the invention, the scope of which is defined in the appended claim.

What I claim and desire to protect is:

The method of manufacturing books from a comb-shaped, permanent binding member of flaccid thermoplastic material, front and back cover sheets, and sheets therebetween, all of said sheets having aligned perforations therethrough adjacent an edge thereof, which method consists of arranging said front cover sheet and said interior sheets in regular sequence, positioning the normally exterior surface of said back cover sheet next to the normally exterior surface of said front cover sheet, chilling said binding member until substantially rigid, guiding the fingers of said binding member through said perforations, respectively, curling said member about said edge so that the free ends of said fingers and the back portion of said member both extend away from said edge, butting said backing portion and the free ends of said fingers together, impressing a high frequency voltage across the contacting surfaces of said member to fuse the same together permanently, and rotating said back cover sheet into its normal position.

ARTHUR BLITSTEIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,710,211 Gammeter Apr. 23, 1929 2,202,097 Farkas May 28, 1940 2,299,061 Spinner Oct. 13, 1942 2,390,125 Schade Dec. 4, 1945 FOREIGN PATENTS Number Country Date 10,862 Australia Nov. 20, 1933

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