US2272126A - Pencil - Google Patents

Description

, l, [UNITED l Patented Feb. 3, 19421 s Smith, Lecnia, N. J., assgnorsztojoseph Dixon, f Crucible Comments, Jersey llilty,v NQ, J,r ,acor- .1, r porationof New Jersey l '2 claims.;` ,49132998312 Y The invention relates to an'improvement. in

' she'athsor casings for elongated implements *of relatively small dameter'or cross section adapted to be 'consumed' or Worn away in use,v Such im'- Vplenients include pencils; erasers, cosmetic and toilet preparations, sharpening stones `for en-- f';1 'avers, jr dental devices, and many other sin'iilar implements in familiar use. It is common practice `to enclose these implements in'a sheathv or casing of wood or paper rleaving asmall' portion of `one end of the core of the implement exposed for use. When the exposed portionof the core has been consumed or Worn away, a freshportion of` theV core is exposed for use by removing a portionjof the'adj'acent end` ofthe sheath, If the sheath is composed o fjwood thisis usually done by meansI of `a knife or bymeans 'of' a mechanical vpencil sharpenerjlfthe sheathl is composed of paper, it usually consists of a weak-'- ly-connected series of Vcoiled strips'jwhich are reinovedone at a time to expose the core;Vv The wooden sheath yis more' universally employed,

especially. as a casing for pencils, the "paper sheathr consisting o f 'spiralsofremovable strips havingr a more restricted use for specialpurposes.

' Ihe presentinvention is more particularly coni cerned Ywith an improvementin s heaths suitable for. cutting bymeans of a' knife or a machine, Since the pencil consisting 'of acore of marking materialvsuch as graphite or crayonenclosed in a sheath 'of wood orpaper is typical lof allthe sheathed, elongated, consumable implements mentioned above, the term pencil will be used generically herein to designate the implement, improvement inthe sheath VVof Whichjis the sub"- ject-matter of the invention.`

"Certain kinds of wood, especially those' popu'- larly known as ceden whether true Cedars or not, have proven satisfactoryfor use as sheaths for,` pencils, with respect to lightness, ease` of ytlie sheath'halxvzes are-made; If `the grains of theopposedjslats differ toor T much, the resulting unevenV expansion of the pencil 'halves' due to absorption 'and' ernissionfofv moisture Vfrequently entails waste" in theform of pencils too crooked to -a'result of theseand other' drawbacks to the use of Wood for pencil sheaths, it has'been proposed to'usje""cheaper; substitutes having all the good qualitijesfof'iwood"'without itsl disadvantages, but

\ -upfto thefjpresentinvention; so far as weare aware; theseproposals havenot resulted in com-vr merciallyl-adapted'pencil v'sheaths to -provide'the Theobj'ect of 'the enti'on is core ofelongated, consumable implements, such as the marking material lof pencils, with asheath having` all thejadvantages Yof the; -sheaths com -A p'o 'ifhigh gradegstraight-grained wood, but whiichcan be produced 'at a cost much less than the cest or woodxsheatns. vTo this end, theinf vention consistsin wrappingaroundl the ,core of the implementa; strip of appropriate flexible sheet materialsubstantiallyas Wide as the core is,jlonggjand'*interposirg between the convolutionsj, or, 'spirals of theV flexible sheet 'material a thi layerof adhesive, solthatthe roll vof ilexible sheetma rial with' the ,interposed` roll` of adhesive togethrfconstitute a solid body, the adjacent,L individual 'spirals or convolutionsof vthe flexible sheet material beingginseparably coni 'necteclv -iii/'ithTeach 'otherjby means;v of the admanufacture intosheathsfand easy'cuttingor l shaving qualities. But cedar'or other wood suitable for lpencil sheaths presents certain"di sad-,`

vantages.: Increasing laborcosts involved in present methods of manufacture; the rising cost of perfect, s1';raigh1 j.-grainedwood;'theL presence Y of a large percentage of cross-grained Wood mixed but fw with' the straight-grained Wood, thereby entailv ifng Waste; and the liability of the wood to attack by fungusk growths, not alwayspossible to detect before manufacture and* which results inv` the weakening of thewood. Moreover, the pen`` cil sheath consistsof twohalves, fand it is aj difficult, if not', impossible task'. match, accu# rately as to "grain the slats or'slabs from which hesive`.' *Several kinds offe'xible sheetl material may be iised, such as paper, Cellophane, cellulose aceta the. cheapest an'dmo'st satisfactory. Any kind of soft,"fexi b1e paper Visv suitable for the purpose, `prefer to use i the kind of f paper known as fnewsprintfi ,Nev'vsprintA `paper `of the typel we prefer tueuse is'a standard product'made rfrom` aboutl 80% ,"of,.lground wood pulp and 20% of silphitejjpulp, vWeighing '32'lbs. per ream,v which l isa bouti3000s`quarefeet.

lsheath composedy of lalternatev layersy or :le 1v wsprint. paper and angappro.-

pinete adhes I i"andflike materials of relatively low den-` sity and' high strength, 'butwe have found paper y V' ng,theadjacent'jlayers or convolutions ofthe paperinseparably together,-

can readily be cut or sharpened by means of a sharp knife blade. The cut surface will be smooth and entirely free from uncut bers or shreds. When however, it is attempted to cut such a sheath in a rotary pencil Sharpener the blades of which have become dulled by reason of long use, it is found that the freshly cut surface of the sheath presents uncut shreds or fibers of the wood or sulphite pulp. In order that the newsprint paper and adhesive sheath may be readily and smoothly cut by means of even a dull rotary pencil sharpener blade, the iibers of the newsprint paper are embrittled by subjecting the newsprint paper to partial char'-l ring or destructive distillation, either by means of heat or chemical action. Thev degree to which partial charring of the paper is carried will depend upon the toughness of the bers of which the paper is composed and the tensile strength of the charred paper. The greater the degree of charring, of course, the easier it; will be to cut the sheath, but'at the same time, the greater the degree of charring, the less tensile strength the paper will have. Accordingly, the degree to which the paper should be charred, either by the application of heat or chemical action, may be readily determined by leaving in the paper sufficient tensile strength to serve as a satisfactory sheath, it having been foundthat when the paper has not been too greatly weakened the bers have been suiciently emb-rittled so that they may be smoothly cut, even b'ya dull spiral Sharpener blade. Usually treatment of the paper at 200 degrees C. for ve minutes will sufficiently embrittle the paper for its intended purposes.

Several kinds of adhesives may be employed, such as dry animal glue dissolved .in a glue to water ratio of approximately 1 to 2, which .is applied at a temperature of substantially 130 F. We prefer, however, to use sodiumisilicate of an alkali-silicate ratio of about 1 to 3.22 diluted with water to a speci'cgravity of 1.3. Such .adhesive functions at normal room temperature as a` satisfactory bond for inseparably binding ltogether adjacent'spirals or convolutions of the roll of sheet material so that the completed sheath is substantially a`sold body resembling in all itsrunctions a sheath composed o-f high grade cedar wood.

To form the improved sheath consisting of a1- ternate'layers or convolutions of flexible sheet material and adhesive, one side of the sheet materialv is completely covered with the liquid adhesive so'that when' the core is applied tothe margin Vof one end of the adhesive-covered s'urface of the sheet material and the margin of the sheet material is wrapped around the core, the core is thereby 'fastened or glued to the sheet material, so that in the completed implementithe core is immovable relatively to' the sheath. As the 'rolling of the core in the adhesive-coated Isheet 'material is continued, the adhesive isof course, spreadonto the uncoated surface'of the sheet material, so that both sides of the sheet material are fully coated with the adhesive with the result that in the completed sheath there is a thin, layer. of adhesive between the adjacent layers or convolutions of the sheet material. This layer or convolution of adhesive is vso thin that for all practical purposes the adjacent layers or convolutions of the sheet material abut eachother. When paper is chosen as the sheet material, it is understood that the paper is sufficiently porous to permit ythe adhesive to penetrate a substantial distance into the sheet from both sides thereof to lock the adjacent layers of sheet material together. As an illustration of the Weight relation between the components of'a sheath which possesses desirable characteristics we give the following, based on the dried material: treated newsprint paper, 84 percent; sodium silicate 16 percent.

In the accompanying drawing illustrating the invention as applied to a pencil, Fig. 1 is a perspective view of the core of marking material and of the flexible sheet material in Which the tion of the "pencil showing the sheet material fully wrappedl around the core; Fig. 4 is a side elevation of the completed pencil, and showing one end of the sheath cut away to expose a portion of the core of marking material for use; Fig. 5 is a transverse section on van enlarged scale throughthe pencil shown in Figs. 3 and 4; Fig. 6` is a"sid.felevation, partly in section, .of a pencil having amodied form'of sheath; and Fig. 'l' is a transverse rsection Aof the pencil shown inFig.6. v

To produce theimproved pencil, or other` implementfhavinga consumable core, of the present invention, the core', indicated at l0, is Wrapped tightlyin a sheath consisting of asheet of appropriate exible material Il, for example, newsprint' paper, coated with'a layer of adhesive l2 in a wet or sticky condition., In Fig. 2 is' shown the step of .winding the adhesive-coated exible sheet material tightlyfaound the core IIJ; It will be understood 'that the sheet material may be a continuous strip,','as', shown in Figs. 1 and 2, or that it maybe fvin sections. Itis sometimes desirable,fdep'endi'ng o'n how fast` the kind of adhesive used dries',lt0` divide the sheet material transvrsely'intojtwo,or'more sections and 'sepa'- rately' wrapj the adhesive-coated sections around the core, permitting the adhesive on .one'section to dry befor'ethe next succeeding section is applied to the partially wrapped core. Since 4the sheetof flexible material is entirely coated 'on at least one side with the wet or sticky adhesive beforevit is, wrapped around' the core, it will" be understood that the' inner spiralor convolution of thesheathradh'eres tightly to the core, so/th'at in the completedpencil', the core of marking material is 'immovable relatively tor the sheath. Moreover' since thev adhesive serves when" dry to bind adjacent'layers `or"convolutions of the flexible sheet material inseparably. together, the alternate layers of slieetimaterial and adhesive become, for the practical purpose 'of serving Vas a sheath for a consumable core, a substantially homogeneous body,' the layers of adhesive being so thin' that'thelayer's of sheet material seem to the unaided eye to be,transverselyalcontinuous body. For the purposes of illustrationfhow.- ever, sincethe adhesivejis an essential partof the sheath,.the layer' of adhesive I2 isindicated in'` the sectional `views bythe division or boundary lin'es I2 inFig. 5"and in Fig'..`7. f

The relationsbetween' stiffness, density, cuttingqualities andsuch yphysical properties of the' ditions under which theconsumable core implement maybe used.' rJhus', if it is. desirable to ,re-y

duce density, a sheet material is selected which Will introduce small, dispersed voids or air spaces into the finished sheath structure. n

'For example, when a sheath of minimumroveral1 density .is produced, the sheath is made up in a plurality of sections as described above one or more of the sections being characterized by the inclusion of dispersed voids or air spaces. As an instance, tliesheath may be made in three sections, the inner section immediately enclosing the core and the outermost sectionl being composed trated as being of circular -outline in cross-section, it is to be understood that'we do not limiti ourselves to this contour sincethe materials may y o be produced in or reduced to other acceptable cross-sectional"outlines, such as hexagonal or oval.

The elongated corevof consumable; material.

' having been' covered with the sheath, as deof alternate layers of smooth paper or other sheet material and adhesive, and the intermediate section, that interposed between the inner and the outermost sections, being so formed that it contains air spaces. In the `modified form of the invention shown'in Figs. 6 and 7, the inner core-enclosing section I5 and the outermost section I6 are composed of alternate layers or convolutions of smooth paper and adhesive, wound tightly together so that there are no air spaces between the layers, whereas the layers of the intermediate section l1 contain air pockets I8 y which may bevariously formed in the structure, as by substantially regularly indenting one or both surfaces of the paper. Although in the step of wrapping the paper or other flexible sheet material around the core the adhesive is applied to both surfaces of the sheet material, it will 4be obvious that the contact between adjacent lay- 5. ers of the sheet material will be only at the raised` points produced by forming the recesses, whereby there will exist a relatively large area ofair spaces between two adjacent layers of section Il,

thereby lessening materially the Weight of the sheath. y

The method of wrapping the corrugated paper of Figs. 6 and l around theinner sheath sections is that'l followed in wrapping an adhesive-covered smooth sheet about the inner 'section in those cases where the sheath consists of a'plurality of sections of smooth paper or other smooth, flexible sheet material.

While the sheath materials are herein illusscribedv above, composed of alternate layers of iiexible sheet .material and adhesive binding ad-` ,y

jacent'layers of sheet lmaterial inseparably together, the outer surface of the outermost layerv of sheet material may be covered with enamel orl other suitable, attractive coating.`

Having thus described the invention what we,

claimy as neW'is:

1. As an article of manufacture, anir'nplement d comprising an elongated consumable core and a sheath enclosingy ther core consisting; of flexible sheet material wound',v around the core Vandv a layer of adhesive between the convolutions of sheet material holding them inseparably together, said sheet material being `,characterized by the fact that it is composed of paper a portion at yleast of which has its surfaces vsubstantiallyregularly indented. l

stantially-regularly indented, and the third secf tion wound around the second section being comi `posed of smoothnewsprint paper. u

vKAY MILLER. HOWARD P. SMITH.

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