US2443185A - Container closure manufacture - Google Patents

Description

June 15, 1948. G, c, ERB 2,443,185

CONTAINER CLOSURE MANUFACTURE 5 Sheets-Sheet 1 Filed April 12, 1946 Arrow/5Y8 -June15,1948. G, c. ERB 2,443,185

CONTAINER CLOSURE MANUFACTURE Filed April 12, 1946 5 Sheets-Sheet 2 ,z m BYj 09 KMOJ/EWL June 15 1948' Filed April 12, 1946 CONTAINER CLOSURE MANUFACTURE 5. Sheet ..s 3

June 15, 1948.

G. c. ERB

CONTAINER CLOSURE MANUFACTURE Filed April 12, 1946 V 5 Sheets-Sheet 4 J. (i 22 mm KMi/M Arron/vars Jun 15, 1948. G. c. ERB 2,443,185

CONTAINER CLOSURE MANUFACTURE Patented June 15, 1948 UNITED STATE-S OFFICE George C. Erb, Forest Hills, N. Y., assig nor to American Can Company, New York, N. Y., a corporation of New J b'rsey Application April 12, 1946,-Serial N0.-6fi1,'1.54

7 Claims. (Cl. 113-121) This invention relates to the method of preparing metallic closures for containers and has particular reference to the manufacture of easy removable sealing caps formed with an integral concentric hollow pull ring surrounding the cap.

An object of the invention is the provision of a method of preparing metallic closures for containers holding carbonated gaseous liquids such as beer and the like, wherein a smooth hollow ring is formed integral with and surrounding a sealing cap which cap may be applied readily to hermetically seal-such a filled container for preserving its contents, the cap being removable without the use of tools by merely lifting and withdrawing the ring to effect opening of the container.

Another object of the invention is the provi sion of a method of making metallic crown cap closures for containers wherein a'central portion of a blank is formed to provide a cap or closure element and wherein an intermediate annular section is cut to provide a space and an integral connection between the closure element and an outer surrounding portion to substantially separate the central and outer surrounding portions so that the latter may be formed into a hollow pull ring for use in removing such caps from sealed containers.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

Figure 1 is a top plan view of a crown cap closure having an integral hollow pull ring adapted for manufacture according to the steps of the present invention;

Fig. 2 is a side elevation of the cap closure and pull ring shown in Fig. 1;

Fig. 3 is a sectional view of the closure illustrated in Figs. 1 and 2 in a sealed position on the mouth of a container;

Fig. 4 is a side elevation showing the pull ring in a raised position as an incident to removing the closure from a sealed container;

Fig. 5 is a plan view on a reduced scale of a blank disc having a drawn central portion which results from the first step of the method ofmaking the crown cap closure;

Figs. 6, 7, 8, 9 and 10 are similar views showing further steps in the manufacture of the closure;

Figs. 11, 12, 13, 14 and 15 are sectional views of the diepa'rts of apparatus suitable for forming l 2 the cap closure in a series of steps according to the present inyentionjlig. 11 showing the step of forming the drawn disc of Fig. 5 and the mechanism being shown in Figs. 12, 13, 14 and 15 producing various steps in the cap closure manu- 'facture as respectivelyshown in Figs. 6 to 9, inclusive;

16 isacross sectionalview taken along the section line l6l6 in Fig. .15; and

Fig. 1!? is-a sectional view of the die parts of apparatus'usedin the final manufacturing step which produces the finished cap of ill. 4

:As a preferredembodiment-ot theIinvention the drawings .illustratefthe manufacture of an easy removable closure orcrown type sealing capA and show the several method'steps constituting the presentinventionrwhlch are used to produce such a closure.

The closure includes alhollow pullring B (Figs. 1 and 2) formed integral with the cap A. Such a ring preferably is connected to the cap by a curved bridge :6. The cap A is sha'pedto provide for a gasket D which forms a sealing area between the cap A and the part of a container E- adapted torecelve the cap; Such aca'p'is crimped in place according to the well known crownsealing type of closure;

Thissealing capis preferably formed from suitable metalf-stook-Ff'iFig. 11) and is first blanked out as a circular disc G (Fig. 5) In the same 0pelalfion-the' cap disc may be drawn or cupped preparatory to providing-for the reception of the gasket D. These two operations are performed in a'sui'tabledie mechanism such as is disclosed in 11. A consideration of this mechanism now will be had.

A stationary die 13 is mounted upon a die support M of conventionalpress construction. The stock' F is positioned over the die l3 preparatory to the blanking an'd drawing operation. The die I3 is removably held in place by clamp bars l5 which are bolted to the die support by cap screws 16.

The die l8 provides the female part for the blanking operation and accordingly is formed with a substantially vertical'cutting wall I! at the center. A draw block 18 is located for slight vertical movement within the opening formed by the 'wall I 1- oftli'e' die l3 and lssupported in the usual manner upon pins connected with the standard rubber'or' spring cushion which provides a-yi'eldlng die element. The draw block I8 is apertured to'p'rovide' a clearance opening 2| and a panel'center block '22 projects up through the aperture; Panel block -his. secured to the die support H by screws 73.

A punch 34 constitutes the male blanking element and is disposed in axial alignment with the die mechanism, the outer diameter of the lower part of the punch cooperating with the cutting wall l l of the die I 3 to blank out the disc G when the punch parts are lowered in the blanking operation. The punch 34 is carried by a crosshead 35 and is secured to the head by cap screws 36. A knockout pad 31 has sliding movement within a central opening 38 formed in the punch 34 and is carried on the lower end of a vertically disposed knockout rod 39 which extends. up throughthe crosshead 35.

A spring 4! surrounds the 'lower" end of the knockout rod and is disposed within a cylindrical opening 42 which merges with the opening 38 of the punch 34. This spring at the lower end rests upon the knockout pad 3'! and is confined at the upper end by a wall f ;;the cylindrical opening.

Prior to the blanking operation, the upper face of the draw block I8 is flush with the upper surface of the die l3. This plane also'includes the top of the panel center block 22. The draw block I8 is held in raised position at such a time, At the time the stock F is inserted into the'die mechanism, the crosshead 35-and' the parts carried thereby are in raised position. The spring 4l holds the knockout pad 31 a slight'distancc below the surface of the punch 34.

When the punch parts descend for this operation the knockout pad 37 first engages the stock F and clamping it against the panel block 22, holds the work in position on the die, The disc G is severed from the stock as the descending punch 34 forces down that part of the stock which is engaged between the punch and the draw block l8. At the same time the center part of the disc, which is prevented from moving down by the panel center block 22, is drawn at its surrounding edges to provide a central cup section 45 (see also Fig. for the disc G.

After the disc has been cut and the center portion has been drawn, the punch is raised whereupon the blanked out disc G is lifted by the rising draw block I8 and the knockout pad 31 operates to eject the disc from the punch mechanism.

In the second operation a slit disc H is produced as shown in Fig. 6. Portions-0f the disc G are pierced or slit to provide this stage in the manufacture of the sealing cap A and this operation may be performed in the mechanism illustrated in Fig. 12. This mechanism comprises a stationary die 52 which is held in the usual manner on a die support 53 by clamp bars 54 secured in place by cap screws 55. The disc G is placed upon the die 52 in an inverted position, i. e., the central panel 45 extends downwardly into a recess 56 formed centrally of the die 52.

The die 52 is formed with a crescent shaped slit 5'! which extends from the top of the die to the top wall of a bottom recess 58. A crescent shaped draw ring 6| extends upwardly through the opening 51 in the die 52 and is an integral part of a circular draw block 62 which is movably located within the recess 58 of the die 52. The draw block 62 is supported in the usual manner upon pins connected with the standard rub-. her or spring cushion which provides a yielding die element. When the work is inserted for this operation the upper face of the draw ring 6| is fiush with the upper surface of the die 52.

The corresponding punch parts for the die members 52, 6| include a knockout disc 64 which is carried on the lower end of a-knockout pad 65 which preferably is a part of a vertically exknockout pad 65 is loosely contained therein. The lower surface of the knockout disc 64 is slightly below the lower surface of the punch piercing die II. It is held in this normal position by a spring 15 which surrounds the rod 66 and is confined within a recess 16 formed in the crosshe'ad 61. The lower end of the spring rests upon the knockout pad 65 and its upper end is confined within the upper wall of the recess 16.

When the punch mechanism is lowered to perform the piercing operation on the disc G the knockout'member 64 first engages the discand holds it on the die with its drawncenter panel 45 resting within the recess 56 and thus centering the work." The piercing punch H cooperating with the crescent shaped slit 5! in the die 52 cuts through the disc-and forces the engaged stock with -the.draw ring. 6| which recedes as the cushion support for the draw block 62 is overcome. 1

The piercing operation removes and slightly lowers a crescent shaped scrap piece .I'! from the disc G leaving acrescent shaped opening 18 and thus forming slit disc HcfFig. 6. Upon thereturn of the punch mechanism the piercing punch ll iswithdrawn from the disc H;Whi1e it is held by the knockout disc 64. The scrap 11 moves back into the-opening 18 of the disc and when the punch element has been fully; raised the disc is released and may beremoved in any suitable The next operation has to do with further drawing a portion ofthe slitdisc H so that the central part assumes the general shape of the crown cap. This produces a cap formed disc J (Fig. :7). This stage in theoperation according to the present method steps may be performed by mechanism illustrated in Fig. -13,an-d reference now will be had to the cap forming oper- The cap forming mechanism of Fig. 13 comprises a central forming die 8i which is mounted upon a. diesupport 82 and is held in stationary position by cap screws 83. A circular draw ring 84 is located above thedie support 82 and surrounds the die 8|. The .draw ring 84 has slight vertical movement relative to the die and is supported in the usual manner upon pins connected with the standard rubber or spring cushion which provides a yielding element. A holding ring 85 surrounds the draw ring 84 and limits its vertical movement. When the slit disc H is first placed upon the die 8| preparatory to the cap forming operation, the disc .is stillin an inverted position, the same as in the mechanism of Fig, 12. The draw ring is in a raised position, its upper surface being .flush with the upper surface of the die. 4

The support ring 85 is bolted by cap screws 86 to the die support 82. At the top the. die. BI is formed with a centrallyfiisposed recess 81 and the drawn center 45 of the slit disc H is adapted to fit snugly within this recess. This centers the slit disc on the die preparatory to the cap forming operation. The die 8! adjacent its upper sur-.

.5 lace is also formed with a conical wall 88. This constitutes the male element for the cap forming operation. 7

The associated punch mechanism for the die 8| comprises a punch 9| which is formed integrally with or is carried on a suitable crosshead body 92; Punch BI is formed with a central opening 9-3 which has diiferent diameters. At the bottom of the punch the opening is outlined by a surrounding conical wall 94 which is coaxial with and parallel to the conical die wall 88.

A knockout pad 95 has restricted movement in the lower end of the opening 93 of the punch 91 and the hottom'part of the pad normallyextends down into the space adjacent the wall 94. It is held in its normal position by a spring 96 which surrounds a knockout rod 91 located in the opening 93. The lower end of the rod is connected with and carries the knockout pad. Spring '96 rests upon the top of the knockout pad and its upper end is confined against the up per wall of the adjacent part of the recess in the punch. At the bottom the knockout pad 95 is formed with a circular projection '98 which snugly fits within the drawn center 45 of the slit disc H when the punch parts descend. This centers and properly locates the disc in the die for the cap forming operation.

When the punch mechanism is lowered upon the slit disc H the projection $8 of the knockout pad 95 first engages within the drawn center 65 of the slit disc and seats that part of the disc fully within the recess 31 of the die. About the same time the punch BI clamps the outer part of the slit disc against the upper face of the draw ring 84 As the punch descends further the spring 96 yields as 'does also the spring cushion supporting the draw ring 84 whereupon that part of the disc surrounding the center 45 and inside of the crescent slit 18 is wiped down over the die BI. In this action the conical wall 88 of the die cooperates with the conical wall 94 of the punch and draws a cap section IIII (Fig. 7) having a short skirt 1'02 for the adjacent area surrounding the crescent shaped slit I8. The section of the cap between the ends of the slit I8 is drawn down even farther into a longer skirt I03 to provide the bridge C for the crown cap. Fig. 13 shows the fully formed disc J as it rests within the die, this being at the time the punch mechanism is on its lowermost stroke.

When the punch 9! moves up the spring 96 still holds the knockout pad 95 against the newly formed disc J whereupon the cushion operating against the draw ring 84 lifts the ring and also the formed disc so that it is brought up above the upper surface of the die BI. At the same time the lower face of the punch 9I moves up to a position above the upper surface of the newly formed disc and these combined actions strip the disc from the die mechanism.

After the cap formed disc J is completed it is usually desirable to trim the outer edge of the disc .prior to further forming operations on the cap. This insures a better formed, more uniformly dimensioned easy open crown cap closure. A trimming die of simple construction is illustrated in Fig, :14 and may be used for this purpose.

The trimming die unit comprises a die I which is mounted upon a die support I06 and is held in place by clamp =bars I01 and cap screws 4-08. Thedie 10.5 is apertured and a cutting wall 411 is formed in the center and adjacent the upthe upper surface of the draw block H2 is flush I with the upper surface of the die I05.

The corresponding punch mechanism comprises a punch member H3 which may be a part of a suitable crosshead H4 disposed for vertical movement and alignment relative to the die.

The punch II 3 is apertured at H5 and a knockout pad H6 is located in the aperture of the punch. This knockout pad is mounted on the lower end of a knockout rod II'I. Normally the knockout pad is disposed in its uppermost position within the recess I I5. It is held by a spring 4 I8 which surrounds theupper portion of the rod IIT and is located Within a recess I I9 formed in the upper part of the crcsshead H4.

The spring I I8 is seated upon the lower wall of the recess H9 and its upper end engages a collar I 2| which is pinned to the upper end of the rod. Recess H5 of the punch H3 is surrounded at the bottom of the recess by a conical wall I22. This wall is of a dimension and angle to snugly fit over the section IBI of the formed cap disc "J.

The cap formed disc J is placed upon the die mechanism for trimming in an upright position. It is located within a locatin ring I23 which is mounted upon the die I and which extends partially around the die. With the disc J in place and supported both by the die I 05 and the draw block H2, the punch mechanism descends. The conical wall I22 of the punch moves down around the formed skirt portions I82, I03 of the disc J and further holds the disc in position for the trimming operation. The trimming operation is performed by the punch I I3 forcing the disc and the draw block H2 downwardly into the position shown in Fig. 14. This cuts through the disc and leaves a surrounding trim I25 which is held in place within the locating ring I23.

As the punch mechanism. is withdrawn the newly trimmed disc (designated by the letter K) moves under action oi the ascending draw block H2 until it is crought back into the plane of the trim l 25. Further upward movement of the punch lifts the trimmed disc K which is frictionally held in the conical wall l 22 of the punch until it is free of the die. A suitable striking force is then applied to the upper end of the knockout rod H 1 this lacing a conventional knockout action which causes the knockout pad IE6 to descend sufiiciently to strip the trimmed disc from the punch mechanism. The scrap trim I25 drops away from the die in the usual manner.

The nest step in. the formation of the crown cap has to do with initially and partially forming the ring B which" it will be recalled is an integral part of the closure, the material for the ring 'b-Billg the stock surrounding the slit 18. This stage in the operation is performed by a punch and die mechanism illustrated in Fig. 15 and the resulting ring formed disc, designated by the letter M. is shown in Fig. 9. During this partial forming of the ring the center cap area. is'not altered in any manner and the trimmed disc K which is to be formed into the ring formed disc M is placed in the die mechanism in an inverted position, that is, with the cap section IUI and skirt extensions I02, I03 at the bottom.

The punch and die mechanism of Fig. com prises a stationary die I3I which is secured by a cap screw I32 to a die supportv I33. The die I3I is formed with a central recess I35 which is nonconcentric with the axis of the die. In the central recess there is disposed a draw block I36 having a locating depression I31 formed in its upper surface.

The draw block I36 has vertical movement within the recess I35 and is supported in the usual manner upon pins connected with the standard rubber or sprin cushion which provides a yielding die element. A central cap screw I36 prevents displacement of the draw block I 36 while allowing for the required vertical movement, this cap screw having threaded connectlonin the die'I3I.

A draw ring I4I surrounds the die I3I and is held in position by a clamping ring I42 secured by cap screws I43 to the die support I33. Draw ring HI has vertical movement withinthe clamping ring I42 and-relative to the ,die I3I. Draw ring I is'supported in the usual manner on pins connected'with the standard rubber or spring cushion which provides a. second yielding die element for this die mechanism. a r

The normal position of the vertically movable members I36, MI is with their upper surfaces flush with theupper surface of the die I3I, The locating depression I31 formed in the draw block I36 provides a centeringpocket for receiving the drawn cap section I IlI "of the trimmed disc K in the die thus locatin'gthe disc preparatory to the ring forming operation.

The corresponding punch mechanism includes an outer punch member I5I which is secured by cap screws I52 to a vertically movable crosshead I53. The punch member I5I is recessed as at I54 to provide .for certain fixed and movablepunch parts, i. e. fixed and, movable relative to the punch. The inner wallof'thisrecess is circular. A central punch member I55 constitutes one of the fixed parts'and is secured by cap screws I55 (see also Fig. 16) to the punch I5I.-- Theinner member I55 has an exterior circular wall which is concentric with and is spaced inside of the inner wall of the recess I54. This exterior circular wall is interrupted on one side by a straight wall I51 for a purpose hereinafter explained.

The movableparts contained within the recess I54 include a tubular clamping ring I6I which fits within the space between the central punch member I55 and the inner wall of the recess I54. The central punch I55 is slotted along parallel lines extending across the center as at I62 and this provides clearance for a connecting bar I63 which extends across the diameter of the punch and which carries the tubular clamping member I6I. By reason of this construction the tubular clamping member may be raised and lowered within the recess I54 of the die I5I.

The bar I63 is carried upon the lower end of a vertically disposed rod I65 which extends up through the crosshead I53. Adjacent the bottom end the rod I65 is formed with a collar I66 which is movable within a tubular recess I61 formed in the crosshead. The normal position of the movable parts of-the punch including the clamping member I6I is with the lower face of the clamping member flush with the lower face of the punch ISI. This is also flush with the lower face of the relatively fixed inner punch member I55.

A spring "I surrounds the rod I65 and is located within the recess I61 of the crosshead I53. This spring normally holds the clamping and with its cap center located within the recess I31 of the draw block I36 the punch mechanism descends and the punch I5I first clamps against the outer flange of the trimmed disc and presses it against the draw ring I4I. Inside of this area of the fiange the clamping ring I6I engages the trimmed disc and presses it down on the forming die I3I. That part of-the punch member I55 which surrounds the pocket I68 engages that portion of the trimmed disc K which is inside of the central area engaged by the clamping ring and presses it against the draw block I36. I

As the descending punch continues its downward movement the clamping block I Hi holds the engaged disc on the stationary die I3I while the parts I5I and I55 move down. The punch I5I bends over the outer edge of the disc in an annular flange I15 (Fig. 9) which extends around the entire disc. At the same time the central punch member I55 wipes down on the inner edge adjacent the slit 18 of the disc and forms an inner circular flange I16 which extends around the disc between the ends of the bridge portion C.

The result of this dual bending on the disc edges is the formation of a U-shaped section I11 which extends around the periphery of the disc excepting the region of the bridge section C. It is this U-section I11 which provides the stock for the pull ring B, the final shaping of the ring as well as a scalloping of the skirt part I02 of the cap taking place in the next and final die operation.

Fig. 10 illustrates the results of the final cap end ring forming operation which creates the easy open closure sealing cap A of Figs. 1 and 2 It is to the die mechanism used in this operation that attention is now directed.

Fig. 17 illustrates a mechanism suitable for completing the formation of the ring and for scalloping the edge of the crown cap. Such a mechanism comprises a center die block I8I which is carried on a die support I62 being held in stationary position by a cap screw I83. A draw ring I84 surrounds the die ISI and has slight vertical movement. This draw ring is retained in position by a clamping ring I85 which is secured by cap screws I86 to the die support I82. The draw ring I84 is supported in the usual manner upon pins connected with the standard rubber or spring cushion and this provides the required yielding die element for the operation under consideration.

The die block I8I is formed with a recess I81 on its upper surface and the cap center of the ring formed disc M is adapted to fit within the recess and thereby to be definitely located when placed within the die mechanism. The ring formed disc M when so located is in an upright position, i. e., in a position reversed from that of the work in the former die mechanism of Fig. 15.

The corresponding punch mechanism comprises a punch I9I formed integrally with or carried by a vertically movable crosshead I92. The

punch I-9I is recessedat 1,93 and the surround ing walls of this recess are shaped to snugly fit over the skirt portions I02, |30f the-ring formed disc M. A knockout pad I94 is seated; within the lower end of a stepped central opening I95 formed in the punch L91 this opening being contiguous with the punch recess I93. Pad I94 is secured to the lower end of a knockout rod I96 which projects up through and extends above the crosshead I92.

A spring I91 surrounds the rod I36 a d rests upon the knockout pad I94: being located, within the upper stepped opening I85 of the punch WI. The upper end of the spring engages the upper end of the wall of the opening and normally holds the knockout pad I94 in a lowered; positionwherein. its lower face is substantially flush with the lower suriacc of the punch I91, A projection 1&8 is formed on the knockout pad I84. and is adapted to seat within the drawn center 45 of the ring formed disc M seated in the die IBL When the unch m hanism des ends Ian-the first leg of its stroke the knockout pad I94 with its projecting face 198 yieldingly clamps down on the center cap portion'oithe disc M as it rests upon the die I81. This holds the parts against displacement for the final forming opera-- tion.

In the lower face of the punch I 9I there is a circular forming groove ZN which coaxially and partially surrounds the center area of the punch being coextensive with the artially formed U-section III of the disc. A similar concentric hemming groove 202- is also formed in the lace of the punch IM andthis extendsin the region f th d c Nmentainins the ridaeQ- After the disc M has been clamped and the punch parts further descend the top edges of the flange I15 and the flange I16 of the U- shaped ring section I'I'I are engaged within the forming groove 29! of the punch and are forced inwardly. At such a time the U -shaped ring part supported upon a U-shaped seat 203 formed in the upper face of the draw ring I84.

Forcing of the flange edges inwardly results in transforming the Ushape ring I" into a completed circular section 204 (Fig. constituting the body of the pull ring B. At the same time that portion of the flange I which is adjacent the, bridge part C is engaged within the groove 202 bent inwardly. The final result is the fo mation of a hem 265 (Fig. 10) interposed betwe 1 the ends of the pull ring B.

The lower tapered Wall of the recess I93 oi the punch till is corrugated or scalloped as at 236 (Fig. 17) and the spaced tapered wall at the top of the die ISI is also scalloped as at 201. The walls 298, 201 cooperate as the skirt I62 of the disc M is clamped between the walls to transform the skirt into a scalloped edge 263 (Fig. 10).

This completes the formation of the crown cap A in the die mechanism of Fig. 17. As the punch parts return to their raised position the knockout pad I94 momentarily remains in place, as the spring IfiI yields, until the punch ml is free of the work. Both punch and knockout pad then are raised clear of the crown cap A still resting upon the die member IBI. During this raising of the punch the cushioned mechanism associated with the draw ring I8 1! causes the latter to lift the drawn cap from the die IBI whereupon the work is discharged as desired.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent terial-leaving a bridge section intact between acentral portion and an outer surr un n p tion, forming the central portion of said material within the crescent shaped opening into a cap ement bydrawing an edge into a depending skirt, andhending the marginal edges of the outer portion outside the said opening into a hulki g-circular in cross section andintegral with and surroundingsaid cap-element for providing an integral cap. removing means for the closure. i

2; The method of preparing" easily removable closnresfor containers and the like, comprising forming a countersunk panel in sheet material, piercing a crescent shaped opening in said material concentricwith and outside of said countersunk panel leaving a bridge section intact .be-. tween a central portion and an outer surround- 11 portion, forming the central portion of said material within the crescent shaped opening and encircling said countersunk panel into a sealing cap element by drawing an edge into a depending skirt, bending the marginal edges of the outer portion outside the said opening into U=shaped laterally extended walls, and pressing said walls into a pull ring integral with and surrounding said cap element for providing an integral cap removing means for the closure.

3. The method of preparing easily removable closures for containers and the like, comprising cutting a disc of sheet material, forming a countersunk panel centrally in said disc, piercing a crescent shaped opening in the disc concentric with and outside of said countersunk panel leaving a. bridge section intact between a central por- I tion and an outer surrounding portion, forming the central portion of said disc within the crescent shaped opening and encircling said countersunk panel into a sealing cap element by drawing an edge into a depending skirt, bending the marginal edges or the outer portion outside the said opening into curved U-shaped laterally extended walls, and pressing said walls into a hol low pull ring integral with and surrounding said cap element for providing an integral cap removing means for the closure.

4. The method of preparing easily removable closure for containers and the like, comprising cutting a disc of sheet material while simultaneously forming a countersunk panel centrally thereof, piercing a crescent shaped opening in the disc concentric with and outside of said countersunk panel leaving a bridge section intact between a central portion and an outer surrounding portion, forming the central portion of said disc within the crescent shaped opening and encircling said countersunk panel into a sealing cap element by drawing an edge into a. depending skirt, trimming the periphery of the disc to a circular outline, bending the marginal edges of the outer portion outside the said opening into curved U-shaped laterally extended walls, and pressing said walls into a hollow pull ring circular in cross section and integral with and sur- 11 rounding said cap element for providing an integral cap removing means for the closure.

5. The method of preparing easily removable closures for containers and the like, comprising piercing a crescent shaped opening in a disc of sheet material leaving a bridge section intact of one side between a central portion and an outer surrounding portion, drawing the central portion of said disc within the crescent shaped opening into a. crown seal cap having a depending wall for engagement with a. container, bending the two marginal edges'of the outer portion of the disc outside the said opening into laterally extended legs forming U-shaped. walls between the edges of said bridge section, and pressing the edges of the legs of said walls together into a pull ring integral with and surrounding the cap for providing an opening means for the closure.

6. The method of preparing easily removable closure for containers and the like, comprising piercing a crescent shaped opening in sheet material leaving a bridge section intact between a central portion and an outer surrounding portion, forming the central portion of said material within the crescent shaped opening into a sealing cap element by drawing an edge into a short skirt merging into said bridge section, bending the marginal edges of the outer portion outside the said'opening into curved U-shaped laterally extended walls, and simultaneously formingsaid short skirt and said bridge section of the closure element into a scalloped annulus to define a crown sealing vcap while pressing said walls into a hollow pull ring integral with and surrounding the-said capfor providing an integral cap removing means for the closure.

crescent shaped opening in the discconce'ntric'""' with and outside of said countersunk panel leaving a bridge section intact between a central portion and an outer surrounding portion, drawing said central portion outside of said countersunk panel into a sealing cap element, bending the marginal edges of said outer surrounding portion into a curved interior upstanding wall extending from one side of said bridge section to the other side and a curved exterior upstanding wall surrounding said disc, pressing said interior upstanding wall and the corresponding part of said exterior upstanding wall directly adjacent into a hollow pull ring integral with and surrounding the closure, and pressing the remaining part of said exterior upstanding wall adjacent said bridge section into a hemmed edge, the said pull ring providing a cap removing means for the closure.

GEORGE C. ERB.

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

UNITED STATES PATENTS Number Name Date 1,257,992 Gavaza Mar. 5, 1918 2,254,682 Hutaff Sept. 2, 1941 FOREIGN PATENTS Number Country Date 542,153 Great Britain Dec. 29, 1941

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