US2447690A

US2447690A - Method of forming crown caps

Info

Publication number: US2447690A
Application number: US486568A
Authority: US
Inventors: John W Ekstedt; Albert F Pitye
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-05-11
Filing date: 1943-05-11
Publication date: 1948-08-24
Anticipated expiration: 1965-08-24

Description

Aug- 24, 1948- J. w. EKsTEDT ETAL uETHoD or Fomuue cnowu ons Filed May ll, 1943 2 Sheets-Sheet 2 Esca-....7 fa

J. W. EKSTEDT ETAL METHOD OF FORMING CROWN CAPS Aug. 24, 1948.

Filed May 11, 194s a xm e W W 'Patented Aug. 241 1948 1 ""Ma'rnon vor ro WING n, l "narrow,imn,nionansaertnruy, i v *Y suman.; Y A l, Y -appucaunnjmayin mensen-al Nana-53s Y' jzbniha. (sa-sar" ,j l A 2 This invention relates toa method oi forming Figure iiisaplan viewof a blank from which a thermo-plastic'crown cap upon a bottleor the the capisformed; f i like. n l l `lligure 5 isanl enlarged transverse vertical sec- An important object of the invention is to tion through the completedcap as applied to provide a method of the above mentioned char.- 5 a hottie, i A ,A l .f i acter, for forming la thermo-plastic cap inplace '.'Flgure'- isaxcentral vertical section through upon a bottle.. fromV a nat blank, and effecting the cap forming meansmats broken away, showthe operation quickly and economically. ing iihe.u blank held in the inclined position, .prior A further object of the invention is to provide to engagement with the bottle, i i a method for rapidly `feeflingfnby gravity the .10 Figure 'I` is a similar view,zshowing the 4bottle heated .thermo-plasticblank to a position torbe raised and the `blank shifted'to the horizontal engaged by the bottlewhenjthe bottlefxrisespand positionfpriorto". the forming operation, to compensate `for the rebounding actionffoffme r `vFigure!! is a similar view," showing the" blank falling blank, prior-ato .its engagement withithe forced upwardlyintotheforming dieyand showbottleY ,f f 1y v n 115 in! the forming and drawing step." A further obiectfoitheinvention-=is:,toprovide v Iig\ire,.!l is asimilar view,.showin`g the-cap a `method of the above lmentioned::character formedupon'the bottleandfstripped from'the which producesa pressing/and drawingraction forming dieux` f 'f f il riff upon the skirt of thethermo-plastic,` cap'-1being ffIn` .therdrawings,v'whereintforfthe purpose of formed=thereby causing the-cap to retainrac- 29 illustration: is lshownfafpreferred i'ormof appacurately its shape `uponfhardeningmnd preserve ratus for the practice of the method, the numeral ingv its binding Ior contacting-engagement with Il: designatesfza'l'verticalistationaryreylindrlcal the bottle." i f fr n; is @1, 1 u sleeve, receivingfthereinw'aresllientfelement Il, A further. object .ofhe invention is` to.A provide which,I may bein zthefiorm cof a rubber-plug,haw a method toeiorce:.theinnel*portionE of. theacap 2,5 ingthe desiredstiilnessfto exertl'a'suitablefdowninto contact withthezinner portion oithecbottle', wardgtorce.c=Thisfiorcefniay befrom"10lbs.`to`250 when the capis xformedandsapplied to the bottle. lbss'pei-.v'square inch.: The"tenslonof therubber x A further` objectvoffthe inventionv isto provide plug mayfbelvariedbyadjustingaplug ibhaving a method-havingwa drawing action.=uponfrthe screwrf threaded: lengagement-.withirrthe" top"`of skirt of,theeheatedfthermo-plasticcapilwhereby -r'o the sleeve, andffhavinga polyonalf` headliby the thickness.-.of-` the sKkirtis reduced andl'aethickmeans of which it mayl be trned The'sleeve ened extension formed ator nearxthe bottoinfof il is preierablyfiormed'ofrmetaland! isprovided the skirt, for interlocking` .engagementwith the at its :lower end withfanrannular recesswil, formheini-0fthebottle;` ai, c; ,fr ing1 a;horizontalshou1der\II; Arrangedmeneath A furthenobjecto he-inventionisstotprovide 35 thesleevef-iliis al centering! or fholding devicepina method di thefg-alziovea-v mentioned character cluding i' a Liverticalisleevez f: Il, alsoifpreferably which strips f the i hardenedpiformed .cap :,uponl the formed f of; metal;` and the: sleeve lllsby bottle from :witliin theav-vforming'fdieg, iter he screws -IJf .or ,theifiikei @This sleevellfhas'ari comp1etionofthe operations.-ff'y a y uppereylindricalwborefllpwhichisf considerably A further objectief theinventi v,i;o p1'ovide` $9 Smaller -iniidiaxnetenthan` the borefofutheizrecess a thermo-plastic; capf-which'millabe securely.- held l l ,'f;and;he nce;,the sleeve :1li: forms: asholdera, upon the` bott-,le and` atiord1 argus tight` Joint;4 v-

arrangedifoppositef the; shoulder` :iii: ,'I'hex` sleeve v and gdygnmesjjff .the `jfwhelitlgx), l hs fa' 10mn-cylindrical :b0l' e12l,:h`avlngl` ,a-cbll will be; apparentd `ngithecourse lie followy siderably y smaller, i diameter thanthe;.,rbo1ie fil; 1,8 deSQriPO!! nuff: e fai 45 and fformln'gaawerticallyf inclined;` shoulderflll. ,Infthe ancornpanyingdraivixu;` A orrningaa This Yvertically-inclined;shouldersextends:"downe 0f this, iplliiimbanm in ywhichflikef numerals wardlygin the; directiomoi-travel: of the iblankftb are employedft d be=descrlbedi,=f-Thef;sleeve 4lhhas avedownwardly flaring? recess Ilka leadingr-intofathe ybore.` En, as Y 1 i t v i, mwnm,Awertically,afinclinedcfslot ,-:22 is/.formed apparatnsemployedinthe-practican! .the method, inthe sleeves t Il iandeilfandlleads into--the bore n, sure2fis, ahorizontalsection takeny on ne Il,` atthehigh endnoi-f,thevshoulderfll ,and the 2.--2 o f F.igurel, K L` bottom.off-thisslot-4is'acontinuation,ofstheshoul-J Figuren? isla similar view takennoniiineaif-J derllfu Y against movement -is a forming and drawing die 22, preferably formed of metal. 'Ihis die is annular and has a vertical bore 24 which is circular in cross section and tapers slightly upwardly. The taper extends from the top of the bore 24 to a rounded outwardly flaring shoulder 2S. The extent of the taperis preferably .010" (ten thousandths of an inch).

Mounted for movement within the die 22 is a forming plug 26, preferably formed of metal, and this plug has substantially a sliding fit within the die 22. The plug is provided at its bottom with a reduced cylindrical extension 21. At its top, the plug 28 has an enlarged portion or flange 28, which engages the top of the die, to limit the downward movement of the forming plug.

lThe elements

21 and 28 are preferably formed integral with the plug 26. The enlarged portion 28 is engaged by the rubber plug il.

Arranged at a suitable elevation above the sleeve Ibis a heating unit-29, preferably lhorizontally disposed. This heating unit has a plurality of spaced fins I3i), forming pockets to receive blanks Si of the thermo-plastic material. This heating unit is turned or indexed so that the heated blanks, one at a time, are discharged in succession into the upper end of a vertical chute 32 having a lower inclined portion 33, in communication with the inclined slot 22.

Arranged beneath the sleeve i6 is a vertically movable plunger 35, supporting a bottle I6 to be raised and lowered thereby. This plunger is in-V eluded in the conventional bottle capping ma chine, wherein the plunger is raised to elevate the bottle during the crowning or capping operation. The bottle has a neck 3l and is provided at its upper end with a bead 2l. This bea-d has an inner transversely convex surface I9 and an outer transversely convex surface Il and a reduced portion or recess l'l beneath the bead.

The blank 3i is formed of thermo-plastic ma terial, and we preferably for-m the blank 3| of cellulose acetate, or a cellulose acetate compound, although other thermo-plastic materials may be used, such as those recited in our copending application for Thermo-plastic crown caps, method of forming the caps, and method of applying the caps tothe bottles,l led November l1,

1942, Serial No.- 465,258 which became abandoned on October 12, 1947.

The practice of the method is as follows:

The bottle `36 is placed upon the plunger and is held in the lowered position. The heater I! is preferably maintained at a temperature of substantially 340 F. and is filled with the cellulose acetate blanks 3| which are heated .to substantially 340 F. The heater I0 is then turned a step and the circular blank 2i, at substantially 340' F. drops from the heater and is supplied to the chute 22 and falls by gravity instantly through the chute and passes through the inclined slot 22 and enters the sleeve I6 and rests upon the inclined shoulder 2|. The invention is not -restricted to heating the blank 3i to 340 F., as the temperature may vary from 250 F. to 340 F. for the cellulose acetate blanks, and for the other thermo-plastic blanks. `It is sumcient to heat the thermo-plastic material so that it will be moldable. There is some tendency for the blank 3| to rebound slightly, when reaching the lower end of the shoulder 2l, and when this occurs, the blank instantly returns to the lowermost position by gravity, since it slides down the inclined shoulder. As soon as the heated blank 3|. iS. in

4 .f the lowermost position upon the inclined shoulder 2|, the plunger Il is moved upwardly. As the bottle is elevated its neck enters the bore 2l, beneath the blank Il. and the bore 2l will serve to center the bottle, if necessary, Figure 6. As the bottle continues to move upwardly,'the bead 20 engages with theheated blank Il and shifts the blank to-a horizontal position, Figure 7, and causes the', blank to move upwardly with the bead, .the bore Ii serving to center the blank upon the bead. Further upward movement of the plunger 'Ii and bottle 2l causes the marginal portion of the blank Il to engage with the rounded edge 2l, whereby such marginal portion is folded or formed -downwardly about .the outer face II of the bead. The continued upward movement of the bottle and blank Il causes the bead 2l and blank 2| to Dass into the bore 24 of the die 23, e

Figure 8.

The upward movement of the blank Il is opposed by .the forming plug 2l, pressed downwardly by the, rubber plug il. This forming plug 26 therefore exerts a downward yielding pressure upon the heated blank 3l and securely presses the upper portion of the blank against the top Vof the bead 2l, while the extension 21produces a depression or recess 42 in the top of the blank and causes the outer portion of this depression .to be forced into engagement with the inner convex face 2| of the bead 2l. As the heated blank-3i is forced upwardly into the forming and drawing die. 2l, while applied to the bead 2l, its marginal portion is folded downwardly over the cuter convex face 40 of the bead. forming a skirt portion 43, of reduced thickness and providing at the bottom of the skirt portion a locking portion 4I of increased thickness. The upward movement of the bottle and blank 2i into the stationary die 23, causes the material of the skirt portion 4l .to be drawn axially and downwardly, as well as forced inwardly against the convex face 4I of the bead. This downward drawing of the material at the skirt portion I3 in some way changes the molecular arrangement or con` dition of the heated thermo-plastic material whereby the formed cap, upon cooling, will retain its precise shape. particularly at the skirt portion, and this skirt portion will remain in firm contact with the outer face Il, thus insuring a gas tight lit, and holding the cap in place upon the bottle. yIt may be that the phase of the thermoplastic material at the skirt portion due to the drawing action, has been somewhat changed, or itv may be that the thermoplastic material at the skirt portion has been drawn or stretched beyond its limits of elasticity. Whatever may be the reason, it has been found that the drawn skirt portion Il will retain its identical shape and size upon cooling, or becoming solid. This is an important feature of the invention, as the diiilculty encountered in the use of .the ordinaryv pre-formed thermoplastic crown cap, is that after -viding a joint which is not gas tight. Since the transverse thickness of the skirt 43 is reduced by the drawing action, the excess thermoplastic material is drawn downwardly below the maximum exterior diameter of the bead Il or convex face 4l, providing a locking portion or shoulder Il of increased thickness. upon the lower end 0f the skirt portion. This thickened lock- "clearlyf' shownin Figure i5. "th

'in'l thickness downwardly' tially o'f inch inl thic greater lthan that of" the topo Q i would depend somewhatupon fthe contourof 5 ing portion Mtbeneathaw'tbeadsll, serves to securely attach the crown canto the bottle., f a

a thickness at its top or subst tiany ,1.

shoulder or portion Il is .The `locking portion 'Il' may t.

the neck 'of the bottle. In" order that the top of the cap would have a thickness of of an inch the original blank 3i would have a thickness of Y of an inch. The die 2l is provided with a bore 24 having a diameter equal to the maximum exterior diameter of the bead Il plus one thickness of the blank 3i. The cellulose acetate blank 3| is heated to substantially 340 F. and applied to the bottle and formed thereon at substantially this temperature to produce the crown cap. The forming operation is effected continuously and quickly by the upward movement of the plunger 35 and the associated forming means. The upward movement of the bottle is effected by the same means and in the same manner as occurs in the conventional crown capping machine. When the bottle is moved upwardly there is a relative axial movement between the die 23 and the bottle lwhich is inwardly toward the longitudinal center of the bottle. Since the diameter ofthe bore 24 of the die 23 is equal to the maximum exterior diameter of the bead Il plus one thickness of the blank Il, the reduced portion of the skirt will be half the thickness of the original blank. Before the blank Il is formed it is fiat and extends radially beyond the maximum exterior diameter of the blank. When the diameter of the blank is reduced, such reduction in the diameter adds to the thickness of the blank at its marginal edge, and since the blank is folded to produce the skirt at the same time that its diameter is reduced, the increase in thickness occurs in the skirt'and this thickness increases toward the marginal'or free edge of the skirt. The skirt is pleated or folded but the pleats or folds do not show since the material is plasticized and the skirt appears integral. The thickened portion 44 is formed to some extent by the material which is obtained by the thinning of the reduced portion of the skirt. The thickened portion M remains considerably beneath the maximum exterior diameter of the bead. The drawing action is axially or longitudinally of the bottle, and inwardly or toward the longitudinal center of the bottle. When used in the description and claims the term axial means longitudinally of the bottle. The term "axially inwardly" means longitudinally of the bottle toward its longitudinal center. Alfter the forming operation is completed, the plunger I5 has a dwell at its top position for about 3 to 3l/2 seconds, which is suilicient to allow the thermo-plastic material to cool and harden. After this, the plunger Il is moved downwardly and the forming plunger 1s moved downwardly by the rubber plugI II and follows the formed cap. The forming plug Il now moves into the die 23 and strips the formed cap from the die. The completed cap is therefore applied to the bottle and separated from the die. The die 23, plunger 20 and contacting elements a-re all at atmospheric or room temperature.

We also ilnd that by the use oi a thermowhich` moves downwardly andfornis the thickened locking-"portion of th`e cap, which locking portionis arran'gedwithin the recess Il, and securely holds the cap to the bottle. Further, the extension 21 forms the recess 42 at the top of the cap, which recess stiiiens the cap, and this also causes the outer portion of the recess to be pressed outwardly and firmly engage the inner convex face Il of the bead. The invention is not restricted to the use of the cellulose acetate blank or thermoplastic blank having a thickness of of an inch, as this thickness may vary somewhat. The thinness of the skirt is not restricted to s of an inch or half of the thickness of the blank, as the thinness of the skirt may vary, but there is a reduction in thickness at the skirt, which results from the drawing action, and produces the excess material to provide the thickened locking part.

It is to be understood that the form of our invention herewith shown and described is to be taken as prefer-red examples of the same,` and that various changes in the shape, size, and arrangement of parts may be resorted to Without departing from the spirit of our invention or the scope of the subjolned claims.

Having thus described our invention, what is claimed is:

l. The herein described method of forming a blank to apply a cap upon a bottle or the like provided with a bead having a maximum exterior diameter, comprising taking a substantially circular blank formed of thermoplastic material and having a greater diameter than the maximum exterior diameter of the bead and heating such blank so that it may be formed and drawn, applying the heated blank tothe free end of the bead in substantially concentric relation thereto so that the marginal portion of the blank extends radially beyond the maximum exterior diameter of the bead, forming the marginal portion of the blank about the outer side of the bead to provide a skirt portion surrounding the bead and extending axially and inwardly beyond the maximum exterior diameter of the bead, subjecting the skirt portion adjacent to the maximum exterior diameter of the bead to an` axial and inward drawing action and thereby reducing the thickness of the skirt portion adjacent to said maximum exterior diameter and maintaining the outer face of the skirt portion and having a greater diameterthan the maximum exterior diameter oi the bead and heating such blank so that it may be formed, applying the heated blank to the i'lree end of the bead in substantial concentric relation thereto so that the marginal portion oi' the blank extends radially beyond the maximum exterior diameter of the bead, eiecting a relative movement in a direction axially of the bottle between the bottle and a rigid tubular die having a. 'substantially cylindrical bore which bore has a diameter equal to the maximum exterior diameter of the bead plus substantially one thickness of the blank and causing the blank and bead to enter the bore, and allowing the i'ormed cap to harden and removing the cap from within the bore.

l JOHN W. EKBTM.

ALBERT F'. PITYO.

ammore crrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,114,323 Westlake Oct. 20. 1914 1,8635081 Bellows June 14, 1932 2,187,190 Wilcox Jan. 16, 1940 l2,210,250!) Strauch -e-., Aug. 6, 1940 `2,325,309 DeSwatt l--.- July 27, 1043 2,431,114 Golding Nov. 18, 1947