US1784906A - Method of embossing fiber sheets - Google Patents

Description

L. OXHANDLER Dec. 16, 1930.

METHOD OF EMBOSSING FIBERVSHEETS Filed Aug. 8. 1927 Q Q Q Patented Dec. 16, 1930 UNITED stares ALE err

LEOPOLD oXHANDLEn, or. CHICAGO, ILLINOIS METHOD or EMBossING FIBER-SHEETS Application filed August 8, 1927. -SerriarlfNro 211,429.

possible effectively to emboss a heavy paper' sheet to a depth and in such a manner as properly to meet the requirements'of a successful cushioning fiat. The naturalV procedure in the manufacture of such embossed sheets would be to pass the brous sheet, immediately after its creation from the mass of pulp, and before drying, between embossing rollers. However, although the sheet would seem at that time to be in such a condition that the fibers would readily slip by eachother and permit a drawing of the sheet to produce an embossed eect the fact is that the fiber sheet is not amenable to being worked in this way and the result that it becomes badly torn in the process.

To a certain extent this case is a continuation of my prior application Serial Number 17 3 529 filed March 7, 1927.

'lhe object of the present invention is to make it possible successfully to emboss a fibrous sheet where the displacement ofthe material must be tol a considerable distance out of the normal plane of the sheet.

The various features of novelty whereby my invention is characterized will hereinafter be pointed out with particularity in the claims; but, for a full understanding of my invention and of its objects and advantages, reference may be had to the following de* tailed description taken in connection with the accompanying drawing, wherein:

Figure 1 is a schematic illustration of my invention; Fig. 2 is a transverse section, on an enlarged scale through two cooperating embossing rollers and a piece of work passing between the same, only fragments of the rollers being shown; Fig. 3 is a plan view of a fragment of the embossed sheet and Fig. 4 is a section taken on line 4-4 of Fig. 3.

I have discovered that if a fibrous sheet,

suchas a sheetof heavy paper, in a very wet condition, is passed'between embossing roller-s whileprotected by a thin flexible covering, preferably fabric, the sheet may'- be deeply embossed without being torn whereas, if it` were not so protected, it would leave the embossing dies full of holes and tears. In some cases itmay be suflicientto place the protective covering on only one side of the fibrous sheet, but where the sheet is lthin and the embossingdeep, it isV advisable to protect both sides or faces.k The fibrous sheet is preferably worked'immediately after its creationv from the pulp andbefore any drying operation thereon, other than that resulting from the preliminary passingof thefsamethrough` rollers.` In this way an embossedysheet is l produced at a cost not much greater thanfthe Vcost of a plain sheet and Vwithout any reworking of a finished product asis the .case in the manufacture of oorrugatedboard.

In the drawing I have illustrated my inven- .tion in connection with the manufacture of a fibrous sheet Av embossed to produce many dome-like elevations a vofconsi'derable height; lbut the invention is not limited to any particular design or to embossing that takes place in one direction from the plane ofthe sheet instead of in both directions, as long as the embossing is effected by deflecting or curving the material Aout of the normal plane along each of a plurality'of lines transverse to eachother. v Y' l Referring to the drawing, 1 and 2 represent cooperating embossing rollers having dies on their peripheries. In thev arrangement shown, the roller 1 has peripheral recesses 3 and the roller 2 has peripheral projections 4' registeringwith and adapted to enter the recesses as the rollers are rotated. In accordance with my invention in its mostl developed form `I layV against the two broad faces of the fiber sheet, in its wet condition, flexible sheets B and C, preferably of fabric. Therefore, when the sheet to be embossed passes through the rotary dies it is clamped between the two protecting sheets and the stresses are distributed throughout the deformed portions, with the resultfthat ing ductile metal and the embossed sheet emerges from the dies in an imperforate condition. o

As heretofore stated, the use of cloth on one face of the brous sheet, say the upper face in Figs. 1 and 2 will' sometimes suffice if the fibrous sheet be not too thin. The protecting coverings may be applied in any suitable way, this being simplya matter of expediency. For example, the protective coverings may be in the form of endless belts each passing over one of the rotary dies and over another roller parallel with the die, suchV additional rollers being-indicated at 5 and 6. On the other hand, the protective coverings may be in the form of long strips that are progressively laid on the fibrous sheet as it passes through the dies and are after- -wards rolled up and used again after its entire length has travelled through the dies.

It will be understood that the present invention does not relate to processes involving mere bending operations, in which the curvature is all in one direction as is the case, for` example, when a sheet 1s corrugated to produce parallel ridges Vand valleys extending entirely across the same; but to processes inl volving a drawing of the material of the sheet bodily to produce a dish-shaped projection or depression. By embossing as used in the claims, I therefore mean such distortion as will produce a. deflection or curving of the materialout of: the normal plane along lines parallel tothe angles to each other.

I claim: y 1. The method of embossing a fibrous sheet, which consists in passing the Same, in a Wet condition, through embossing rollers while in contact with a' flexible sheet strong enough to prevent it from being torn by the rollers plane and at right and forcing separated areas of the sheet Vbodily out of the plane of the sheet.

2. The method of embossing a fibrous sheet, which consists in passing the same, saturated with moisture, through embossing rollers with a thin flexible sheet interposed between at least one face thereof and the corresponding roller and forcing separatedv areas of the sheetbodily out of the plane ofthe sheet.

3; The method of producing an embossed paper sheet, which consistsin making a paper sheet in the usual manner and, before it is dried and while still wet, passing it and an overlying thin flexible sheet between embossing rollers and forcing separated lareas of the sheet bodily out of the plane of the sheet.

In'testimony whereof, I sign this Yspecilication.

-LEoPoLD oxHANDL-ER.

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