US2177879A - Method of making bookbinding cases - Google Patents

Description

Oct. 31', 1939. i F s, SCHADE 2,177,879

METHOD OF MAKING BOOKBINDING CASES Filed March 23', 1938 ATTORNEYS Patented Oct. 31, 1939 UNITED STATES PATENT OFFICE METHOD OF MAKING EUOKBINDING CASES Application March 23, 1938, Serial No. 197,578

6 Claims. (Cl. 281--29) I This invention relates to an improved method of making a cover or case for permanent or loose leaf bookbinding. In making up loose leaf binders or covers it is customary to use case making machines. They deliver a finished case consisting of two covers hinged to a back panel. They are commonly made of cardboard with metal stiffening strips, cover, and lining material. The cover material which gives the outside appearance and wearing quality is of cloth in the better grades, as compared to decorative paper in the lower grades.

Prior to my invention herein disclosed, others have disclosed various Ways of making bookbinding cases with the cover or back panel portions or both of stiffening and decorating material, such as Bakelite, for example. So far as I know, the methods of proceeding which use such material as Bakelite in the prior art are too expensive to extend down and give their benefits to books in the lower price classes. For this reason I have worked out, as the principal purpose of the present invention, a method of using the superior material, such as Bakelite, and in the g5 manufacture of low cost binders where it has heretofore been prohibitive. And in accomplishing my purpose, the low cost bookbinding case resulting'from the method steps is given new characteristics of substantial utility.

A brief illustration of one form of the method will be given, utilizing the product, a bookbinding case, as disclosed in my prior Patent 1,983,883 of Dec. 11, 1934. This product is made at an exceedingly low cost. Having the present inven- 35 tion in mind, I may use material for making the case according to the prior method but of a kind that will readily absorb a coating from a solution of thermo-plastic material. So far as the automatic case making machines are concerned I proceed as if the case were to be completed with only the material fed to the automatic machines. Having first made a complete bookbinding case in the known economical manner, I dip the whole case into a solution of thermo-plastic material. The latter will penetrate the material of the case by absorption and its whole surface will thus be given a penetrating coating. Then the dipped case is placed in a mold and subjected to heat and pressure, to set the plastic composition coating. The hinge lines, however, can be left without pressure in the mold, as I will show, so the material along those lines will not be brittle after the coating has set. The hinges are, therefore, left so that they may turn easily as desired. EX- cept for the hinge lines, the whole binding case 'are of paper or cloth.

will be given a highly polished surface finish of thermo-plastic molded character. And the only cost is the material cost for the coating, the cost of dipping, and the cost of molding under heat and pressure. It is already customary to make the structural form of a case with the back panel flat, as the cover portions are flat, and then if a curved back panel portion is desired, to give the back panel a curved cross-section, by molding under heat and pressure. Most cases are made with a curved back panel and this operation can be usefully combined with the molding of the thermo -plastic substance on the whole surface of the case. That is to say, the cost of molding the case, or at least the back panel portion, under heat and pressure is not an entirely new cost when the case is finished with a thermo-plastic material.

The method eliminates the major portion of the labor heretofore contemplated in using thermo-plastic material for book protection and the expected improvement in appearance.

The general foregoing disclosure is perhaps sufiicient for a skilled man to practice the in vention, but I will refer to the accompanying drawing and following description for a more specific disclosure.

Fig. 1 is an end view of a bookbinding case as finished by the case making machines, but before pp Fig. 2 is a like view after clipping;

Fig. 3 is a sectional view, on a smaller scale, of a suitable mold for applying heat and pressure to the binding case;

Fig. 4 is a view like Fig. 1 but showing the finished case; and

Fig. 5 is a detail of a modified form of mold.

I will disclose first the practice of my invention with reference to the binder case shown in my said prior Patent 1,983,883. Accordingly, Fig." 1 illustrates the loose leaf book-binding case, with its back panel 3 flat and before it is molded into curved form. It is in the form which can be made by automatic machinery at very low cost. In that form the stiffening material for the covers I and 2 and back panel 3 is of cardboard. The back panel is also stiffened with a very thin strip 8 of sheet metal. The hinge strip I4 and the outside cover strip l5, cooperating with strip M at the back panel to make the cover hinges, are preferably of cloth. The lining strips it on the inside of the covers, and overlapping strips i4 and I5, In Figs. 1, 2, and 4 the thickness of the materials has been exaggerated for clarity, and in Figs. 1 and 2 the parts are shown separated to indicate conventionally that they have not been finally pressed into their final position.

The article of Fig. 1 is the article of my prior patent, a complete bookbinding case of low cost. It has not the utility of the present invention built into it but as to form and structure it is the same. As to its material, it may be he samenamely, a laminated structure of cardboard, cloth, and paper strips. However, in practicing the present invention I choose the condition of the outside strips such as M, 5, and it, with a view to their being given a final finish quite differently than before. That is to say, in my prior method these strips were given their surface finish before they were assembled into book form. In my present method they are given their surface finish and other advantages after they are assembled into book form. For this reason the surface of the strips before they are built into book form is preferably left in condition, i. e., with unfinished surfaces, so that the finishing thermo-plastic material may easily penetrate and fill the pores at the surface of the bookbinding case.

For convenience I will refere to the finishing material as thermo-plastic substances-Bakelite, as one example. The invention is not limited to any one of the many kinds of substances having the plastic molding properties I want. These known substances are the kind which are brought to a finished condition by the action of heat and pressure. They give a highly polished finish and become hard, provided both heat and pressure are used as they set into final form. If pressure is not used with the heat, the substance does not become hard and I utilize this feature as I will point out. I prefer to use the variety of plastics which are called thermo-setting, in that the mold used to apply heat and pressure need not be cooled off before emptying the mold. These are distinguished from the variety called non-thermo-setting which need to have the mold cooled before emptying. The chief difference of utility with respect to my invention is in the speed at which I desire to manufacture to keep the cost low. But both varieties may be used without departing from the main features of the invention. I shall use the term thermo-plastic substance to include any one of the general class of these substances, which are so well known in plastic molding arts today, such as phenol, cresol, or urea formaldehyde condensation products, nitro-cellulose products, cellulose acetate products, casein products, and rubber or shellac products.

With a thermo-plastic substance in the form of a bath of cement or varnish, I dip the book structure of Fig. 1 into the bath long enough for a filling of pores in the book structure. This will result in a very thin layer of the cement lying all over the surface of the book structure. This layor will not, according to my preferred practice, be built up to any substantial thickness, although in some cases that may be desired.

Fig. 2 indicates the condition after dipping into the cement bath, it being understood that, while shown as a single line 2B, the moldable substance of the bath has penetrated the pores below the outside surface of the book material.

The dipped book structure is then put in a mold as indicated at 2!, 22 in Fig. 3. Heat and pressure are applied to finish the surface of the Whole bookbinding case. Then it is taken out of the mold appearing as in Fig. -i, with a highly polished hardened surface. The mold may be formed as indicated at 23 in Fig. 5, so that no pressure will be applied along the hinge lines. Consequently, the material on, and slightly absorbed along these lines due to the dipping step will not be hardened. Thus, the hinge lines are left for their desired flexibility. In the illustration the mold preferably applies both heat and pressure everywhere else except the hinge lines or paths for bending. The finished book structure then is characterized by the molded finish of a layer of the thermo-plastic substance which encases the desired structure. In the case of the construction of Fig. 1 the absence of any filling between the members It and id at the hinge lines 24 and 25 will operate to relieve the pressure at these points, and the mold has therefore been shown in Fig. 3 without special provision for relieving the pressure.

It should be noted that the molding step may also shape the back panel from fiat to curved form, or may leave the back flat as in the example shown in 5. Also, from the manner of constructing the binder case of Fig. 1, in which the various strips and laminations are merely pasted together, the addition of the molded finishing material results in bonding the parts together in a much more secure manner, as well as sealing all joints and the surface of the whole against the deleterious action of air and moisture. In the example given of making the loose leaf binder case, it would be desirable to provide the desired rivet holes for attaching the loose leaf metal before the molding step.

The method may be used with a large variety of particular book cover or case forms-for example, more expensive forms than the one shown. The covers and back portion may be made up into case form before the dipping and molding step and made of duck, linen, or any of the known materials just so long as the material will take the material for molding. If for any reason other surface parts than the hinge lines or paths are desirably left without a hardened surface, this can be easily arranged by making the mold as in Fig. 5, so that pressure is not applied in the molding step to such parts. I have not illustrated the varieties of other completed book case forms, or covers for post binders and the like, which generally have no back panel, that may be used with advantage in practicing my invention. They are so well known that I have confined my specific description to the low cost manufacture of loose leaf bookbinding cases. This is the field where I consider improvement is most needed to raise the quality of the product. But very definite advantages also lie in the application of desired book case surfaces in large bookkeeping ledgers, etc, where it is objectionable to add materially to the already high cost, as by making the prefabricated panels of Bakelite or like laminations before building such panels into book case form. So far as I know, my method results in a substantially lower cost than any prior practice for getting a comparable finish on book-binding cases.

The method may also be followed by using an outer lamination for the cover which has its thermoplastic material applied to it before fabrication instead of afterwards, either by impregnation or coating in such a manner as not to interfere with fabricating the entire cover as an integral whole by ordinary methods, and molding this inchoate cover into final form under heat and pressure. The method may also be practiced by building up the cover in any desired way into an integral Whole, and then molding it under heat and pressure in a mold into which the thermoplastic material has previously been introduced in thin sheet form. Other adaptations of the method to other products, and variations in the manner of applying the thermo-plastic material, may be made within the scope of the appended claims.

Having disclosed my invention, I claim:

1. The method of making a bookbinding case which consists in making up the assembly of fibrous layers and strips in the form of covers, flexible hinges, and back panel portions all joined into a functional unit, then coating the whole unit with a penetrating spread of an amorphous thermo-plastic substance, and finally molding said spread under heat and pressure applied on the top and bottom surfaces of the cover and back panels but without pressure on the flexible hinge portions.

2. The method of making a loose leaf bookbinding case by assembling fiat cardboard-containing panels for covers and back with a sheet metal stiffening panel laminated in the back, joining the flat panels to the usual fibrous strips for hinging, lining, and panel-covering purposes, applying a thin amorphous spread of a thermoplastic substance to coat and partially penetrate the fibrous material of the case, molding such substance on the case as a core by applying both heat and pressure except along the hinge lines, and in this molding operation pressing the stiffened back panel into curved transverse form.

3. The method for the purpose described which consists in making up a bookbinding case as a unit of back, flexible hinges, and cover parts, covered with fibrous material applying an amorphous spread of a thermo-plastic material over said fibrous material for penetrating and covering the same, then molding said substance to hard-surfaced highly polished form while using the whole binding case unit as a core and during such molding applying heat and pressure for such form except along the hinge lines, the pressure on the hinge lines being avoided.

4, A process of making covers for bindings having an integral hinge portion, comprising adherently covering a body portion with an outer lamination, supplying said outer lamination with a charge of thermo-setting material, and molding the cover as an integral whole under heat and pressure while maintaining the pressure at said hinge lines below that which would cause setting of said thermo-setting material.

5. A process of making covers for bindings having an integral hinge portion, comprising adherently covering with an outer lamination a body portion formed of separate pieces separated at the hinge line, supplying said outer lamination with a charge of thermo-setting material, and molding the cover as an integral whole under heat and pressure, the separation of the pieces of the body portion preventing the application of a setting pressure to the thermo-setting material at the hinge lines.

6. The method of making loose leaf binder cases which consists in laminating fibrous layers and strips comprising the body and outer portions of said panels with unfinished surfaces on the outside of the panel and with the contacting surfaces on the interior of the panel adhesively secured together, then applying an amorphous spread of a thermo-plastic substance to coat the case and penetrate into the fibers of the unfinished surfaces, and finally molding said substance to hard-surfaced highly polished form by application of heat and pressure while using the panel unit as a core.

FRANK STANLEY SCI-IADE.

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