US2772012A - Method and device for manufacturing closure caps and closure cap produced thereby - Google Patents

Method and device for manufacturing closure caps and closure cap produced thereby Download PDF

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Publication number
US2772012A
US2772012A US225494A US22549451A US2772012A US 2772012 A US2772012 A US 2772012A US 225494 A US225494 A US 225494A US 22549451 A US22549451 A US 22549451A US 2772012 A US2772012 A US 2772012A
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Prior art keywords
cap
closure
plunger
skirt
shell
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US225494A
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Harold L Crabtree
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Anchor Hocking Glass Corp
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Anchor Hocking Glass Corp
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/68Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts by incorporating or moulding on preformed parts, e.g. inserts or layers, e.g. foam blocks
    • B29C70/78Moulding material on one side only of the preformed part
    • B29C70/80Moulding sealing material into closure members
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/02Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles
    • B29C43/18Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles incorporating preformed parts or layers, e.g. compression moulding around inserts or for coating articles
    • B29C43/183Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles incorporating preformed parts or layers, e.g. compression moulding around inserts or for coating articles the preformed layer being a lining, e.g. shaped in the mould before compression moulding, or a preformed shell adapted to the shape of the mould
    • B29C43/184Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles incorporating preformed parts or layers, e.g. compression moulding around inserts or for coating articles the preformed layer being a lining, e.g. shaped in the mould before compression moulding, or a preformed shell adapted to the shape of the mould shaped by the compression of the material during moulding
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32Component parts, details or accessories; Auxiliary operations
    • B29C43/36Moulds for making articles of definite length, i.e. discrete articles
    • B29C43/3607Moulds for making articles of definite length, i.e. discrete articles with sealing means or the like
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32Component parts, details or accessories; Auxiliary operations
    • B29C43/36Moulds for making articles of definite length, i.e. discrete articles
    • B29C43/361Moulds for making articles of definite length, i.e. discrete articles with pressing members independently movable of the parts for opening or closing the mould, e.g. movable pistons
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32Component parts, details or accessories; Auxiliary operations
    • B29C43/56Compression moulding under special conditions, e.g. vacuum
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D41/00Caps, e.g. crown caps or crown seals, i.e. members having parts arranged for engagement with the external periphery of a neck or wall defining a pouring opening or discharge aperture; Protective cap-like covers for closure members, e.g. decorative covers of metal foil or paper
    • B65D41/02Caps or cap-like covers without lines of weakness, tearing strips, tags, or like opening or removal devices
    • B65D41/16Snap-on caps or cap-like covers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32Component parts, details or accessories; Auxiliary operations
    • B29C2043/3205Particular pressure exerting means for making definite articles
    • B29C2043/3255Particular pressure exerting means for making definite articles springs
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32Component parts, details or accessories; Auxiliary operations
    • B29C2043/3272Component parts, details or accessories; Auxiliary operations driving means
    • B29C2043/3283Component parts, details or accessories; Auxiliary operations driving means for moving moulds or mould parts
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32Component parts, details or accessories; Auxiliary operations
    • B29C43/36Moulds for making articles of definite length, i.e. discrete articles
    • B29C43/361Moulds for making articles of definite length, i.e. discrete articles with pressing members independently movable of the parts for opening or closing the mould, e.g. movable pistons
    • B29C2043/3615Forming elements, e.g. mandrels or rams or stampers or pistons or plungers or punching devices
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2793/00Shaping techniques involving a cutting or machining operation
    • B29C2793/0081Shaping techniques involving a cutting or machining operation before shaping
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00Moulds or cores; Details thereof or accessories therefor
    • B29C33/34Moulds or cores; Details thereof or accessories therefor movable, e.g. to or from the moulding station
    • B29C33/36Moulds or cores; Details thereof or accessories therefor movable, e.g. to or from the moulding station continuously movable in one direction, e.g. in a closed circuit
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2705/00Use of metals, their alloys or their compounds, for preformed parts, e.g. for inserts
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S264/00Plastic and nonmetallic article shaping or treating: processes
    • Y10S264/76Processes of uniting two or more parts
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S264/00Plastic and nonmetallic article shaping or treating: processes
    • Y10S264/78Processes of molding using vacuum
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S425/00Plastic article or earthenware shaping or treating: apparatus
    • Y10S425/038Pre-form
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S425/00Plastic article or earthenware shaping or treating: apparatus
    • Y10S425/809Seal, bottle caps only

Definitions

  • the present invention relates to the manufacture of closure caps, and more particularly to a method and device for manufacturing closure caps and to the improved closure cap produced thereby, having gaskets or coatings formed therein from a piece of moldable material.
  • a cup-shaped shell for a closure cap may first have placed therein a piece or slug of material such as uncured rubber compound; the piece of material is thereafter subjected to the action of av pressure member which deforms the material and forces it into contact with shell walls to form it into desired shape.
  • av pressure member which deforms the material and forces it into contact with shell walls to form it into desired shape.
  • the plastic or moldable compound may be forced into the shape of an annular gasket which extends around the skirt portion of a closure cap, and in other instances the compound may be squeezed to form such agasket and also completely cover the underside of a top panel of the closure cap.
  • the closure formed by the present method eliminates so-called pinholes.
  • Most food products when packed in closed containers attack the metal of the closure cap sealing the container. This slow action tends to form pinholes which perforate the metal. Of course, any perforation permits air to enter the container, and the product is spoiled. Enormous quantities of packaged foods have been spoiled due to this tendency of the product to attack the metal. It is not possible to coat the metal with lacquers which will eliminate the difficulty.
  • the present invention aims to overcome the above and other difficulties by providing a new and improved method and device for manufacturing closure. caps. by shaping under high pressure a molding compound within a cap shell so as to conform to appropriate portions of the shell and to so effectively unite the shaped compound with shell surfaces that the compound cannot be separated without considerable effort; thereafter an edge of the shell is preferably inturned to lock the molded material into position.
  • the invention further contemplates a new and 2,772,012 Patented Nov. 27, 1956 improved means and method of preventing the formation of cavities or blisters in the material which is shaped to form a gasket or interior coating in the closure cap.
  • the invention aims to provide an improved closure cap and package.
  • An object of the present invention is to provide a new and improved method. of manufacturing closure caps.
  • Another object of the invention is to provide a new and improved device for manufacturing closure caps.
  • Another object of the invention is to provide an improved closure cap and package.
  • Another object is to provide a new and improved means and method of minimizing or preventing the formation of defects such as cavities in the gaskets or interior linings of closure caps.
  • Figl is a diagrammatic view illustrating the manufacture of a closure cap according to the present invention.
  • Fig. 2 is a sectional view illustrating one means for practicing the present invention
  • Fig. 3 is an enlarged fragmentary sectional View illustrating the parts of Fig. 2 in another position;
  • Fig. 4 is an enlarged fragmentary sectional view of a device for shaping the moldable material, embodying plunger with a different shaped lower end than that of Figs. 2 and 3;
  • Fig. 4a is a sectional view showing a molding press generaly similar to that of Figs. 2 and 3 but embodying certain refinements thereover;
  • Fig. 5 is an enlarged fragmentary sectional view showing a portion of a closure capmanufactured by the present method and device
  • Fig. 6 is an enlarged fragmentary sectional view also illustrating a portion of a. closure cap, similar to that of Fig. 5 manufactured by the present method and device;
  • Fig. 7 is a plan view, partly broken away, showing a square slug of moldable material with corner portions retaining it in position within the shell;
  • Fig. 8' is a plan view, partially broken away, showing a triangular slug of moldable material with corner portions thereof retaining, the slug in position Within the cap shell;
  • Fig. 9' is an enlarged fragmentary sectional view showing a portion of modified closure cap manufactured by the present method and device.
  • Fig. 10 is a fragmentary sectional view showing a container having sealed thereto a closure cap of the present invention.
  • Fig. 1 there is shown in diagrammatic form various steps preferably utilized to produce the present closure cap, a completed cap beingshown at the right side of the figure.
  • the invention will be described chiefly with reference to its use in manufacturing a closure cap having both and annular gasket portion and a thickness of material lying against the underside of. the cap cover portion.
  • Certain features of the. invention may be used to produce a closure cap embodying a ring gasket. with or without the layer of mate rial underlying the entire cover portion.
  • the closure cap shell is stamped and formed from a strip of suitably coated sheet metal (not shown) so that ithas an inset center portionz, annular. offset cover groove 4 and depending skirt portion 5, as illustrated at V 3 r a in Fig. l.
  • the shells are formed so that a coated surface of the sheet is disposed inwardly, the preferable coating being a vinyl base coating.
  • the juncture of skirt and groove may be as shown in the enlarged view
  • the deformable material which is used to form the gasket and coveringlayer at the interior of the shell will be described as comprising some suitable rubber compound or material, it being intended that this terminology include the various examples referred to herein as well as other materials-or compounds having appropriate qualities.
  • the molding materials may be of any desired color for giving a pleasing appearance with the particular material to'be packaged; for example,.when the caps are used for dark colored jams or jellies, the molding material may have a matching dark color, and when used for packaging cheeses it may be of lighter matching color.
  • the rubber compound may I be' formed into one or more strips 12 of appropriate width and thickness by any suitable machine, for example by that shown in expired Patent No. 1,871,560. 'Such a machine is indicated generally in Fig. l by reference character 13. k A strip 12 is then severed by shear 14 into slugs 18 of desired length or suitable slugs may be punched from the strip..
  • the shape and thickness of the slugs should be suitable to the particular closure caps in which they are to be formed. With a shell diameter of. about 2%" and a skirt length of about i thesslug may be about one inch square and A" thick; these are merely examples. A circular or other shape of slug could also be used.
  • the slugs may have marginal portions that project beneath the skirt flange 6 and engage the skirt 5, such as the corners of the square and triangular slugs shown in Figs. 7 and 8 respectively, to thereby retain the slugs within the cap shells. However, some areas of the top panel within the confines of the skirt are preferably left uncoveredby the slug which is placedin the shell.
  • fiat slugs may be positioned by hand within closure cap shells adjacent central parts thereof, as indicated .at b in Fig. l, or may be guided thereto by a chute 15. In this relationship, the shell is supported and the slug squeezed under high pressure so as to displace portions of it to cover the center panel, fill the groove 4 in the top of the cap, and extend upwardly along the skirt 5, as shown at 0.
  • a reciprocable plunger 21 shown carrying a rel-" 7 extensions of the plunger, and may be normally urged downwardly by springs 26 positioned intermediate the plunger projections 25 and the relatively movable memher 22.
  • sealing means 28 at the underside of the movable member contacts the surface 29 of the cap supporting mem-v ber 20 and co-operates therewith and with the plunger 21 to form a chamber around the shell and its slug of moldable material 18.
  • a sealing means 31 may be intermediate the plunger v 21 and movable member 22 to minimize leakage of air between the members.
  • a vacuum conduit 34 is operatively connected with a suitable exhausting device to withdraw air from the cap-enclosing chamber.
  • a suitable exhausting device to withdraw air from the cap-enclosing chamber.
  • This may be achieved in any suitable manner; for example a projection 35 of '.a valve 37 may strike an adjustable screw 36, to thereby open the valve 37, which connects the conduit 34 with a vacuum tank or other means forv withdrawing air from the interior of the cap chamber through the conduit 34 and a passageway 39 of the movable member 22.
  • Withdrawal of air from the chamber thus commences prior to the lowermost surface 40 of the plunger 21 coming into contact I with the rubber slug 18,.upon continued downward movement of the plunger.
  • the sealing ring 28 may be of round, square, or any other appropriate cross section. being retained in a correspondingly shaped groove.
  • the amount of pressure required to deform the slug' 18, 18a, or 18b is influenced by the particular composition of the plastic material.
  • total load per cap may be in the neighborhood of eight tons. This, of course, will also vary with the size of theslug which must be reformed, as wellas with the particular material of the slug. With a load of eighttons the pressure is in the neighborhood of 4,000 pounds per square inch; it is preferably not less than about 3,500
  • This method of reforming the molding slug under high pressure causes portions of it to shift outwardly from central locations over underlying portions of the top panel and thence along the skirt so that it scrubs or squeegees air film molecules off the vinyl base coating or a metal surface to give a bond or uniting between the compound and underlying coating or metal that is very difficult to break.
  • the strength of this bond is undoubtedly due in large measure to the high pressure utilized to reform the slug and force it against the interior of the cap, and it is believed that absorbed surface films of air are so broken or weakened that there is obtained a molecular interlocking between the compound material and the underlying vinyl base coating or metal.
  • the bond obtained is so strong that the plunger 21 may be pulled out of the resulting cup-shaped liner or gasket without the necessity of first heating the cap in order to get suflicient adherence between the material and the cap so that the plunger will not pull the molded material loose as it moves away from the cap.
  • the bond obtained is so strong that the plunger may actually be hotter than the cap and yet not pull the liner loose as it moves out.
  • the above high pressure action supplements the simultaneous withdrawal of air that creates a partial vacuum and is particularly useful and desirable in manufacturing the present closure caps at high speeds.
  • the high pressures utilized give flow and adherence of the lining at temperatures which will avoid objectionable hardening of the material of the lining so that the precise nature of the lining as to hardness and other sealing qualities may be predetermined and retained during reformation of the slug.
  • the caps with the molded material therein may be subsequently subjected to heat for curing and in this way render the closures suitable for sealing products requiring a cured or vulcanized gasket.
  • the uniform density and toughness obtained by the high pressures utilized is in all probability due to squeezing minute amounts of adhered or adsorbed air out of the slugs and in achieving a closer contact between the particles which comprise the slug material.
  • closures may be subsequently heated to vulcanize the rubber and secure greater toughness and hardness, such subsequent heating is neither necessary nor desirable for sealing many types of products.
  • lighter pressure does not give the uniformly dense and tough gaskets obtained by those formed under the preferred pressures of about 3,500 to 10,000 pounds per square inch.
  • the pulling down force on the closure cap is not sufiicient to cause the container rim to dig its way entirely through any portion of a liner or gasket formed under the above pressures, even where the rubber is unvulcanized.
  • the inset center portion 2 provides a desired depth to the groove 4 around the periphery of the center portion.
  • the horizontal portion of a gasket formed in the groove 4 provides a top seal for a container and the vertical wall portion of a gasket provides a side seal for a container.
  • the end of the plunger may have an annular portion 48 (Fig. 4) which projects beyond the remainder thereof; this offset part 48 serves to press the moldable material firmly into the annular cap recess and may even inset it slightly.
  • the cap supporting member 20 and the reciprocable plunger 21 may be heated by suitable electric heaters or plates 45 and 46. These may partially vulcanize a rub ber compound during its formation within the cap, and the cap may be subsequently subjected to additional heat for completing the vulcanization, for example by exposing them to a battery of infra-red lamps as the caps move through a suitable tunnel or passing them through a vulcanizing oven.
  • the heaters 45 and 46 of the cap support member and plunger may be heated to any appropriate temperatures. Good results will be achieved with some compounds by maintaining the plunger heater at a temperature of about 160 F. and the cap support heater at about F., giving a general average temperature of about F. Preferable temperatures of cap and molding material at the end of the molding operation are in the order of 130 F. to F.
  • one or more ducts 43 may be provided in the plunger 21 (Fig. 2) to receive, during displacement of the slug 18, any excess rubber compound comprising the slug. It is preferred not to have such ducts, however, as they generally allow objectionable protuberances to form. Air is not drawn into the cap chamber through the ducts, as they are generally blocked by excess slug material.
  • the flange 6 of the shell Adjacent the end of the molding stroke of the plunger 21, the flange 6 of the shell is turned inwardly toward the center panel of the closure to fit around and grip the shaped molding compound. This may be accomplished by an inclined shoulder 50 on the plunger 21, which strikes against the inwardly extending flange 6 and bends it toward the cover portion of the cap.
  • the means for evacuating the cap chamber preferably remains connected during inturning of the cap lower edge so that no air is trapped between the gasket and the edge of the skirt during its inward turning, where it might tend to blow the gasket edge laterally upon release of pressure caused by inward movement of the plunger 21.
  • the molding press illustrated in Fig. 4a is similar to that of Figs. 2 and 4 but embodies certain refinements.
  • ejector means is shown in the support member 20a for lifting closures when the ejector is elevated by the underlying reciprocable cam
  • a chute is provided at the left side for guiding closures away from the machine
  • upright rods are shown for guiding the plunger-carrying means during reciprocation by the piston rod and its hydraulic cylinder indicated at the top of the figure.
  • a bell crank at the right side of the figure may be actuated with the plunger to operate the ejector-elevating cam.
  • Figs. 5 and 9 Final preferred shapes of the cap edge are illustrated in the enlarged view of Figs. 5 and 9 where the inwardly disposed surface of the inturned skirt is shown forming substantially a continuation of the surface of the skirt gasket portion.
  • the completed closure cap may thus be readily fitted downwardly over the mouth of a container.
  • the skirt and cover portions may merge together as shown in Fig. 5 or may be more rounded at their juncture as indicated in Fig. 9.
  • the more rounded contour of Fig. 9 is desirable as it facilitates flow and even distribution of molding material during pressing of the slug and further minimizes the possibility of trapping air in or beneath the molding material.
  • the rounded connecting portion may have a radius of about A of an inch.
  • each closure cap produced by practicing the present method has a uniform and neat appearance, even though the moldable compound may not be suflicient to contact the underside of the inwardly extending flange 6 prior to inward turning thereof.
  • the thickness of the gasket may be varied by insetting' the cover portion an appropriate distance. Where the plunger 7 has an'offset annular ridge 48 (Fig. 4), this also serves to shape the rubber slug adjacent the groove wall 411 of the cap.
  • the final closure shown and described herein preferably has a rubber thickness at its cover portion of about $5000 Of an inch.
  • the gasket material sho'wn in Figs. 5 and9 is thinner adjacent lower portions; of the cap than adjacent upper portions, which provides a larger diameter so that the cap may readily fit down over a container side wall.
  • the lower innersurface of the material may be inclined as shown in Fig. 5 or may be substantially cylindrical as shown in'Fig. 9. 7
  • the container may have a thickened upper edge or bead so that the reformed or displaced'rubber compound of the gasket may interlock beneath such head or edge.
  • a similarlrelationship exists when the closure cap of Fig. 5 is applied to the container. 7
  • the plunger 21 moves 7 completely away from it.
  • Completed closures may be removed from their seats in the seating member 20 in any suitable manner, for example by a cam-operated ejector member,iand sent to means for completing vulcanization .
  • a cam-operated ejector member,iand sent to means for completing vulcanization may be removed from their seats in the seating member 20 in any suitable manner.
  • the evacuating struction shown and described is preferred, however, as it vfacilitates operation of the method and provides a rela- .tively simpledevice for withdrawing air prior to the instant at which the plunger comes into contact with a slug of material 18. 7
  • the present invention provides a new and improved method and device for manufacturing passages 39 and conduit 34 are shown provided in the stripper member 22, they could V instead-be provided in the plunger member 21.
  • With the present method and device obiectionable cavities in the moldable material are either minimized or eliminated; the resulting gasket of substantially uni metal of the cap; The tenacity of the bond between the liner or gasket and the shell of the cap is so strong that.
  • Air is withdrawn from a closed chamberwhich con-' is achieved simultaneously with evacuation of air from: the cap and the containing chamber, so that there. is little V likelihood of trapping air at the rear or some other portion of the moldable material.
  • the inturned edge of the cap skirt conceals the edge of the'rubber and permits consideri of the closure cap.
  • the cover portion of a closure cap is preferably inset i with respect to an annular marginal portion to provide a groove which is adapted to hold a greater mass of material at that portion adapted to contact and form a seal with'the rim of a container. 'In addition to forming a seal at the upper part of the rim, a closure manufactured" container.
  • L'A sheet metal closure cap of the class described I comprising a top portion and a depending cylindrical skirt, a rubber compound forming an imperforate covering over the entire inner'walls of said top portion andldepending skirt, said covering having its greatest thickness along the upper portion vof the skirt fortelescoping over and engaging the side wall of a container, the inner sur face of the covering along the lower portion of the skirt flaring downwardly, and the lower edge portion of the skirt'being turned about the lower edge of the covering and enveloping the same in clamping relation.
  • a sheet metal closure cap of the class described i comprising a top portion and. "a depending'cylindrical” ing an imperforate covering over the entire inner surface and being bonded thereto bysaid lacquer coating, said 7 and a lower edge portion of said skirt extending inwardly and upwardly about the lower edge portion of thecovering enveloping and concealing saidlower the covering.
  • skirt said top portion and skirt having their inner surface covered by a lacquer coating, a rubber compound forme.
  • a closure cap' which comprises providing a cup-shaped shell having a top panel, and skirt portion, and an inwardly projecting annuing the topand adjacent portion of the skirt to prevent deformation thereof, heating said shell and said material to at least partially vulcanize saidv material, withdrawing air from the interior of said shell, subjecting said piece of material to pressure to force it to flow along the bond to said panel and skirt and during the application of said 1 pressure, bending said inwardly projecting annular flange toward the top panel to coverand clamp in position adja- 2 cent portions of said reformed piece of rnateriaL.
  • the siug reforms under this high pressure,- portions of it scrub so closely along interior surfaces of the cap that adsorbed suriace films of air are broken or weakened and a very strong interlock, probably molecular, is'obtained between slug material and cap surfaces.
  • closurecap adapted to form a hermetic seal on a glass container which comprises placing within said cup-shaped a shell a slug of unvulcanized rubber compound adapted to Y ilow upon subjection to pressure, supporting the'top and;
  • a device for forming sealing gaskets in cup-shaped shells having top and skirt portions in the manufacture of closure caps comprising the combination of means for supporting the top and adjacent portion of the skirt to prevent deformation thereof, a plunger insertable into said shell for displacing portions of a plastic sealing material such as uncured rubber to conform to an interior surface of said shell and to provide a sealing gasket therefor, means carried by and movable with respect to said plunger for sealing said shell within a substantially air tight chamber, means for withdrawing air from the interior of said shell, and means on said plunger for turning a skirt portion of said shell over a depending portion of said material at the time of displacing portions of the sealing material.
  • a plastic sealing material such as uncured rubber

Description

Nov. 27, 1956 H. L. CRABTREE METHOD AND nsvrca FOR MANUFACTURING CLOSURE CAPS AND CLOSURE CAP PRODUCED THEREBY 5 Shets-Shcet 1 Filed May 10. 1951 0 i1 45 4 \\\((IIIIIIIIIIIIIII illli IN V EN TOR. [lam/d L (24%! 1956 H. L. CRABTREE METHOD AND DEVICE F MA ACTURING C URE CAPS AND CLOSURE P DUCED THER Filed May 10, 1951 3 Sheets-Sheet 2 3. B1, Ham/d Z, 5
Nov. 27, 1956 EVI CAPS AND CLO CIE. CRABTREE SUR 2,772,012 METHOD AND D FOR MANUFACTURING CLOSURE E CAP PRODUCED THEREBY Filed May 10, 1951 3 Sheets-Sheet 3 1: mil
INVENTOR. fiara/d frail]?! United States Patent METHOD AND DEVICE FOR MANUFACTURING CLOSURE CAPS AND CLOSURE CAP PRODUCED THEREBY Harold L. Crabtree, Lancaster, Ohio, assignor to Anchor Hocking Glass Corporation, Lancaster, Ohio, a corporation of Delaware Application May 10, 1951, Serial No. 225,494
8 Claims. (Cl. 215-49) -The present invention relates to the manufacture of closure caps, and more particularly to a method and device for manufacturing closure caps and to the improved closure cap produced thereby, having gaskets or coatings formed therein from a piece of moldable material.
This application is in part a continuation of application Serial No. 137,857, filed in the United States Patent Oflice on January 10, 1950.
With the present method and device, a cup-shaped shell for a closure cap, usually of sheet metal, may first have placed therein a piece or slug of material such as uncured rubber compound; the piece of material is thereafter subjected to the action of av pressure member which deforms the material and forces it into contact with shell walls to form it into desired shape. In some instances, the plastic or moldable compound may be forced into the shape of an annular gasket which extends around the skirt portion of a closure cap, and in other instances the compound may be squeezed to form such agasket and also completely cover the underside of a top panel of the closure cap.
In addition to the other features of the invention, I have discovered that in practicing .the method under normal conditions blisters form on the rubber material in the closure and that the blisters are caused by small bubbles of air being compressed to a high degree by the pressure used in molding the rubber. When this high pressure is removed, the air expands to cause blisters or ing the air from the chamber formed during the liner, By thus. evacuating the air from in molding operation. and around the rubber slug. at the time of the molding operation, trapped air is minimized and blisters cease to be a problem. The metal of the closure, or a coating thereon, is completely covered with rubber and the exposed surface of the rubber is smooth and adapted to form an excellent seal.
In addition to forming an excellent seal, the closure formed by the present method eliminates so-called pinholes. Most food products when packed in closed containers attack the metal of the closure cap sealing the container. This slow action tends to form pinholes which perforate the metal. Of course, any perforation permits air to enter the container, and the product is spoiled. Enormous quantities of packaged foods have been spoiled due to this tendency of the product to attack the metal. It is not possible to coat the metal with lacquers which will eliminate the difficulty.
The present invention aims to overcome the above and other difficulties by providing a new and improved method and device for manufacturing closure. caps. by shaping under high pressure a molding compound within a cap shell so as to conform to appropriate portions of the shell and to so effectively unite the shaped compound with shell surfaces that the compound cannot be separated without considerable effort; thereafter an edge of the shell is preferably inturned to lock the molded material into position. The invention further contemplates a new and 2,772,012 Patented Nov. 27, 1956 improved means and method of preventing the formation of cavities or blisters in the material which is shaped to form a gasket or interior coating in the closure cap. In addition, the invention aims to provide an improved closure cap and package.
An object of the present invention is to provide a new and improved method. of manufacturing closure caps.
Another object of the invention is to provide a new and improved device for manufacturing closure caps.
Another object of the invention is to provide an improved closure cap and package.
Another object is to provide a new and improved means and method of minimizing or preventing the formation of defects such as cavities in the gaskets or interior linings of closure caps.
Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.
A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings, forming a part of the specification, wherein:
Figl is a diagrammatic view illustrating the manufacture of a closure cap according to the present invention;
Fig. 2 is a sectional view illustrating one means for practicing the present invention;
Fig. 3 is an enlarged fragmentary sectional View illustrating the parts of Fig. 2 in another position;
Fig. 4 is an enlarged fragmentary sectional view of a device for shaping the moldable material, embodying plunger with a different shaped lower end than that of Figs. 2 and 3;
Fig. 4a is a sectional view showing a molding press generaly similar to that of Figs. 2 and 3 but embodying certain refinements thereover;
Fig. 5 is an enlarged fragmentary sectional view showing a portion of a closure capmanufactured by the present method and device;
Fig. 6 is an enlarged fragmentary sectional view also illustrating a portion of a. closure cap, similar to that of Fig. 5 manufactured by the present method and device;
Fig. 7 is a plan view, partly broken away, showing a square slug of moldable material with corner portions retaining it in position within the shell;
Fig. 8'is a plan view, partially broken away, showing a triangular slug of moldable material with corner portions thereof retaining, the slug in position Within the cap shell;
Fig. 9'is an enlarged fragmentary sectional view showing a portion of modified closure cap manufactured by the present method and device; and
Fig. 10 is a fragmentary sectional view showing a container having sealed thereto a closure cap of the present invention.
Referring again to the drawings, and more particularly to Fig. 1, there is shown in diagrammatic form various steps preferably utilized to produce the present closure cap, a completed cap beingshown at the right side of the figure. For purposes of convenience, the invention will be described chiefly with reference to its use in manufacturing a closure cap having both and annular gasket portion and a thickness of material lying against the underside of. the cap cover portion. Certain features of the. invention may be used to produce a closure cap embodying a ring gasket. with or without the layer of mate rial underlying the entire cover portion.
The closure cap shell is stamped and formed from a strip of suitably coated sheet metal (not shown) so that ithas an inset center portionz, annular. offset cover groove 4 and depending skirt portion 5, as illustrated at V 3 r a in Fig. l. The shells are formed so that a coated surface of the sheet is disposed inwardly, the preferable coating being a vinyl base coating. The juncture of skirt and groove may be as shown in the enlarged view For purposes of convenience, the deformable material which is used to form the gasket and coveringlayer at the interior of the shell will be described as comprising some suitable rubber compound or material, it being intended that this terminology include the various examples referred to herein as well as other materials-or compounds having appropriate qualities. It will be clear that various suitable synthetic or natural rubber compounds maybe utilized, as well as materials other than rubber compounds, without departing from the spirit and scope of the invention. The-present invention is not intended to be limited to any particular molding compound or material, as the method and device are equally useful with various ones. Synthetic -materials could he used which would be ready for use immediately upon being shaped into desired formation within the closure cap. The rubber compound is preferably in uncured or unvulcanized condition when placed into the shell and may, if desired, be subsequently vulcanized to the desired state of hardness, elasticity, strength, etc. The molding materials may be of any desired color for giving a pleasing appearance with the particular material to'be packaged; for example,.when the caps are used for dark colored jams or jellies, the molding material may have a matching dark color, and when used for packaging cheeses it may be of lighter matching color. The rubber compound may I be' formed into one or more strips 12 of appropriate width and thickness by any suitable machine, for example by that shown in expired Patent No. 1,871,560. 'Such a machine is indicated generally in Fig. l by reference character 13. k A strip 12 is then severed by shear 14 into slugs 18 of desired length or suitable slugs may be punched from the strip..
The shape and thickness of the slugs should be suitable to the particular closure caps in which they are to be formed. With a shell diameter of. about 2%" and a skirt length of about i thesslug may be about one inch square and A" thick; these are merely examples. A circular or other shape of slug could also be used. The slugs may have marginal portions that project beneath the skirt flange 6 and engage the skirt 5, such as the corners of the square and triangular slugs shown in Figs. 7 and 8 respectively, to thereby retain the slugs within the cap shells. However, some areas of the top panel within the confines of the skirt are preferably left uncoveredby the slug which is placedin the shell.
The relatively thin fiat slugs may be positioned by hand within closure cap shells adjacent central parts thereof, as indicated .at b in Fig. l, or may be guided thereto by a chute 15. In this relationship, the shell is supported and the slug squeezed under high pressure so as to displace portions of it to cover the center panel, fill the groove 4 in the top of the cap, and extend upwardly along the skirt 5, as shown at 0.
is placed in a recess in a support member positioned beneath a reciprocable plunger 21, shown carrying a rel-" 7 extensions of the plunger, and may be normally urged downwardly by springs 26 positioned intermediate the plunger projections 25 and the relatively movable memher 22.
As the plunger. 21 and member 22 move downwardly,
sealing means 28 at the underside of the movable member contacts the surface 29 of the cap supporting mem-v ber 20 and co-operates therewith and with the plunger 21 to form a chamber around the shell and its slug of moldable material 18. A sealing means 31 may be intermediate the plunger v 21 and movable member 22 to minimize leakage of air between the members.
At about the time that the sealing ring .28 contacts the surface 29 of the cap supporting member 20, a vacuum conduit 34 is operatively connected with a suitable exhausting device to withdraw air from the cap-enclosing chamber. This may be achieved in any suitable manner; for example a projection 35 of '.a valve 37 may strike an adjustable screw 36, to thereby open the valve 37, which connects the conduit 34 with a vacuum tank or other means forv withdrawing air from the interior of the cap chamber through the conduit 34 and a passageway 39 of the movable member 22. Withdrawal of air from the chamber thus commences prior to the lowermost surface 40 of the plunger 21 coming into contact I with the rubber slug 18,.upon continued downward movement of the plunger. The sealing ring 28 may be of round, square, or any other appropriate cross section. being retained in a correspondingly shaped groove.
When the movable member 22 contacts the cap support member 20, its movement is arrested but the plunger 21 continues to move downwardly in opposition to the spring or springs 26 and its lower surface comes into' contact with the rubber slug 18.. The pressure exerted by the plunger 21 causes the slug material to flow firstradially outwardly and thence down along the cap skirt into the shape illustrated at c of Fig. 1.
The amount of pressure required to deform the slug' 18, 18a, or 18b is influenced by the particular composition of the plastic material. total load per cap may be in the neighborhood of eight tons. This, of course, will also vary with the size of theslug which must be reformed, as wellas with the particular material of the slug. With a load of eighttons the pressure is in the neighborhood of 4,000 pounds per square inch; it is preferably not less than about 3,500
pounds per square inch regardless of cap size and mate- 7 I have discovered rial being molded, and may be more. thatby using pressures from about 3,500 pounds per 7 square inch to about 10,000 pounds per square inch, I
get a very superior bond of the cap and its vinyl base coating with liner or gasket, as well as liners or gaskets of optimum and uniform density and toughness throughout the layer 10 and annular portion 9, which is of great importance as it insures uniform sealing pressures against the rim and annular sealing zone of containers.
These pressures are so high that they are obtained by a hydraulic press. The uniform density and toughness and superior bond thus obtained makes it difficult to scrape away with a suitable instrument the lining or gasket so as to expose the underlying metal and prevents removal in normal conditions of usage. Applying this With some materials, the
pressure for a period of about two to four seconds will give good results.
This method of reforming the molding slug under high pressure causes portions of it to shift outwardly from central locations over underlying portions of the top panel and thence along the skirt so that it scrubs or squeegees air film molecules off the vinyl base coating or a metal surface to give a bond or uniting between the compound and underlying coating or metal that is very difficult to break. The strength of this bond is undoubtedly due in large measure to the high pressure utilized to reform the slug and force it against the interior of the cap, and it is believed that absorbed surface films of air are so broken or weakened that there is obtained a molecular interlocking between the compound material and the underlying vinyl base coating or metal.
The bond obtained is so strong that the plunger 21 may be pulled out of the resulting cup-shaped liner or gasket without the necessity of first heating the cap in order to get suflicient adherence between the material and the cap so that the plunger will not pull the molded material loose as it moves away from the cap. As a matter of fact, the bond obtained is so strong that the plunger may actually be hotter than the cap and yet not pull the liner loose as it moves out. The advantage of thus being able to heat both plunger and cap is that it permits supplying just sufiicient heat during pressing to render the pressure highly effective in the distribution of the material and reduces the time required for application; this heat makes the material flow easier.
The above high pressure action supplements the simultaneous withdrawal of air that creates a partial vacuum and is particularly useful and desirable in manufacturing the present closure caps at high speeds.
The high pressures utilized give flow and adherence of the lining at temperatures which will avoid objectionable hardening of the material of the lining so that the precise nature of the lining as to hardness and other sealing qualities may be predetermined and retained during reformation of the slug. If desired, the caps with the molded material therein may be subsequently subjected to heat for curing and in this way render the closures suitable for sealing products requiring a cured or vulcanized gasket.
The uniform density and toughness obtained by the high pressures utilized is in all probability due to squeezing minute amounts of adhered or adsorbed air out of the slugs and in achieving a closer contact between the particles which comprise the slug material.
While the closures may be subsequently heated to vulcanize the rubber and secure greater toughness and hardness, such subsequent heating is neither necessary nor desirable for sealing many types of products.
While lower pressures may be used to reshape a slug so that it conforms to a cap shell with apparatus of relatively light construction, the lighter pressure does not give the uniformly dense and tough gaskets obtained by those formed under the preferred pressures of about 3,500 to 10,000 pounds per square inch.
Even though the interior of the container may be subjected to an unusually high vacuum, the pulling down force on the closure cap is not sufiicient to cause the container rim to dig its way entirely through any portion of a liner or gasket formed under the above pressures, even where the rubber is unvulcanized.
Where a plunger 21 with a flat end is used, the inset center portion 2 provides a desired depth to the groove 4 around the periphery of the center portion. The horizontal portion of a gasket formed in the groove 4 provides a top seal for a container and the vertical wall portion of a gasket provides a side seal for a container. If desired, the end of the plunger may have an annular portion 48 (Fig. 4) which projects beyond the remainder thereof; this offset part 48 serves to press the moldable material firmly into the annular cap recess and may even inset it slightly.
The cap supporting member 20 and the reciprocable plunger 21 may be heated by suitable electric heaters or plates 45 and 46. These may partially vulcanize a rub ber compound during its formation within the cap, and the cap may be subsequently subjected to additional heat for completing the vulcanization, for example by exposing them to a battery of infra-red lamps as the caps move through a suitable tunnel or passing them through a vulcanizing oven. The heaters 45 and 46 of the cap support member and plunger may be heated to any appropriate temperatures. Good results will be achieved with some compounds by maintaining the plunger heater at a temperature of about 160 F. and the cap support heater at about F., giving a general average temperature of about F. Preferable temperatures of cap and molding material at the end of the molding operation are in the order of 130 F. to F.
If desired, one or more ducts 43 may be provided in the plunger 21 (Fig. 2) to receive, during displacement of the slug 18, any excess rubber compound comprising the slug. It is preferred not to have such ducts, however, as they generally allow objectionable protuberances to form. Air is not drawn into the cap chamber through the ducts, as they are generally blocked by excess slug material.
Adjacent the end of the molding stroke of the plunger 21, the flange 6 of the shell is turned inwardly toward the center panel of the closure to fit around and grip the shaped molding compound. This may be accomplished by an inclined shoulder 50 on the plunger 21, which strikes against the inwardly extending flange 6 and bends it toward the cover portion of the cap. The means for evacuating the cap chamber preferably remains connected during inturning of the cap lower edge so that no air is trapped between the gasket and the edge of the skirt during its inward turning, where it might tend to blow the gasket edge laterally upon release of pressure caused by inward movement of the plunger 21.
The molding press illustrated in Fig. 4a is similar to that of Figs. 2 and 4 but embodies certain refinements.
For example, ejector means is shown in the support member 20a for lifting closures when the ejector is elevated by the underlying reciprocable cam, a chute is provided at the left side for guiding closures away from the machine, and upright rods are shown for guiding the plunger-carrying means during reciprocation by the piston rod and its hydraulic cylinder indicated at the top of the figure. A bell crank at the right side of the figure may be actuated with the plunger to operate the ejector-elevating cam.
Final preferred shapes of the cap edge are illustrated in the enlarged view of Figs. 5 and 9 where the inwardly disposed surface of the inturned skirt is shown forming substantially a continuation of the surface of the skirt gasket portion. The completed closure cap may thus be readily fitted downwardly over the mouth of a container. The skirt and cover portions may merge together as shown in Fig. 5 or may be more rounded at their juncture as indicated in Fig. 9. The more rounded contour of Fig. 9 is desirable as it facilitates flow and even distribution of molding material during pressing of the slug and further minimizes the possibility of trapping air in or beneath the molding material. With a cap of about 2%." diameter, the rounded connecting portion may have a radius of about A of an inch.
In addition to securely gripping the gasket material, the inturned edge of the skirt also conceals any uneven edge or gap 51 which may form on the material due to placing too small a slug in a shell, as indicated generally in Fig. 6. Thus each closure cap produced by practicing the present method has a uniform and neat appearance, even though the moldable compound may not be suflicient to contact the underside of the inwardly extending flange 6 prior to inward turning thereof.
. of the shaped material.
mines the thickness of the gasket formed in the groove.
7 The thickness of the gasket may be varied by insetting' the cover portion an appropriate distance. Where the plunger 7 has an'offset annular ridge 48 (Fig. 4), this also serves to shape the rubber slug adjacent the groove wall 411 of the cap. The final closure shown and described herein preferably has a rubber thickness at its cover portion of about $5000 Of an inch.
The gasket material sho'wn in Figs. 5 and9 is thinner adjacent lower portions; of the cap than adjacent upper portions, which provides a larger diameter so that the cap may readily fit down over a container side wall. The lower innersurface of the material may be inclined as shown in Fig. 5 or may be substantially cylindrical as shown in'Fig. 9. 7
As either of the closures shown moves down over a container, due to external pressureo'r vacuum from the interior of the container, material from the thickened upper gasket portion is reformed or displaced so as to move toward the lower thinner cross section and press radially inward against an annular sidewall portion of the container below its rim. The relationship between a container and closure cap such as that of Fig. 9 sealed thereto is illustrated in Fig. 10, and it will be noted that the gasket.
material bulges or protrudes inwardly at 8 so as to contact adjacentportions of the container side wall 3. If desired,
the container may have a thickened upper edge or bead so that the reformed or displaced'rubber compound of the gasket may interlock beneath such head or edge. A similarlrelationship exists when the closure cap of Fig. 5 is applied to the container. 7
Upon completion of molding, the plunger 21 moves 7 completely away from it. Completed closures may be removed from their seats in the seating member 20 in any suitable manner, for example by a cam-operated ejector member,iand sent to means for completing vulcanization .While the evacuating struction shown and described is preferred, however, as it vfacilitates operation of the method and provides a rela- .tively simpledevice for withdrawing air prior to the instant at which the plunger comes into contact with a slug of material 18. 7
it will be seen that the present invention provides a new and improved method and device for manufacturing passages 39 and conduit 34 are shown provided in the stripper member 22, they could V instead-be provided in the plunger member 21. The conclosure caps, as well as an improved closure cap and sealed 7 package. With the present method and device obiectionable cavities in the moldable material are either minimized or eliminated; the resulting gasket of substantially uni metal of the cap; The tenacity of the bond between the liner or gasket and the shell of the cap is so strong that.
the'reis very little likelihood of their separation.
Air is withdrawn from a closed chamberwhich con-' is achieved simultaneously with evacuation of air from: the cap and the containing chamber, so that there. is little V likelihood of trapping air at the rear or some other portion of the moldable material. The inturned edge of the cap skirt conceals the edge of the'rubber and permits consideri of the closure cap.
able leeway in the rubber forced up about the periphery The cover portion of a closure cap is preferably inset i with respect to an annular marginal portion to provide a groove which is adapted to hold a greater mass of material at that portion adapted to contact and form a seal with'the rim of a container. 'In addition to forming a seal at the upper part of the rim, a closure manufactured" container.
As various changes may bernade in theform, construction and arrangement of the parts herein without depart ing from the spirit and scope of the invention'and without sacrificing any of its advantages, it is to be understood" that all matter herein is to be interpreted as illustrative and not in a limiting sense. 7
Having thus described my invention, I claim:
L'A sheet metal closure cap of the class described I comprising a top portion and a depending cylindrical skirt, a rubber compound forming an imperforate covering over the entire inner'walls of said top portion andldepending skirt, said covering having its greatest thickness along the upper portion vof the skirt fortelescoping over and engaging the side wall of a container, the inner sur face of the covering along the lower portion of the skirt flaring downwardly, and the lower edge portion of the skirt'being turned about the lower edge of the covering and enveloping the same in clamping relation.
2. A sheet metal closure cap of the class described i comprising a top portion and. "a depending'cylindrical" ing an imperforate covering over the entire inner surface and being bonded thereto bysaid lacquer coating, said 7 and a lower edge portion of said skirt extending inwardly and upwardly about the lower edge portion of thecovering enveloping and concealing saidlower the covering.
skirt, said top portion and skirt having their inner surface covered by a lacquer coating, a rubber compound forme.
edge portion of 3. The method of manufacturing a closure cap' which comprises providing a cup-shaped shell having a top panel, and skirt portion, and an inwardly projecting annuing the topand adjacent portion of the skirt to prevent deformation thereof, heating said shell and said material to at least partially vulcanize saidv material, withdrawing air from the interior of said shell, subjecting said piece of material to pressure to force it to flow along the bond to said panel and skirt and during the application of said 1 pressure, bending said inwardly projecting annular flange toward the top panel to coverand clamp in position adja- 2 cent portions of said reformed piece of rnateriaL.
4. The method as claimed in claim 3, whereinsaid pressure is applied for a period of about two to four 7 seconds.
5. The method as claimed in claim wherein said unvulcanized rubber compound is' heated to a temperature talus the closure cap and the moidable slug is simultaneously subjected to extraordinarily high pressure. As
the siug reforms under this high pressure,- portions of it scrub so closely along interior surfaces of the cap that adsorbed suriace films of air are broken or weakened and a very strong interlock, probably molecular, is'obtained between slug material and cap surfaces. Turning the edge 2 or skirt of the closure toward a cover portio'npf the cap Of ab0l1tl30 F. to 1 0 F. during subjection to said 5 pressure.
closurecap adapted to form a hermetic seal on a glass container which comprises placing within said cup-shaped a shell a slug of unvulcanized rubber compound adapted to Y ilow upon subjection to pressure, supporting the'top and;
adjacent portion of the skirt to prevent deformation thereof, withdrawing air from the interior of said shell to form a partial vacuum about said slug and subjecting said slug to plunger pressure in the range of 3,500 to 10,000 pounds per square inch to cause it to flow under high pressure over the inside surface of the shell into the shape of a sealing gasket and in so doing to scrub the air film ofi the surface of the shell and to provide a molecular bond with the inside of the cup-shaped shell.
7. The method as claimed in claim 6 wherein the inside of the shell is coated with a bonding material.
8. A device for forming sealing gaskets in cup-shaped shells having top and skirt portions in the manufacture of closure caps comprising the combination of means for supporting the top and adjacent portion of the skirt to prevent deformation thereof, a plunger insertable into said shell for displacing portions of a plastic sealing material such as uncured rubber to conform to an interior surface of said shell and to provide a sealing gasket therefor, means carried by and movable with respect to said plunger for sealing said shell within a substantially air tight chamber, means for withdrawing air from the interior of said shell, and means on said plunger for turning a skirt portion of said shell over a depending portion of said material at the time of displacing portions of the sealing material.
References Cited in the file of this patent UNITED STATES PATENTS Beher Aug. 26, Morrison May 14, Taliaferro Dec. 16, Eberhart Mar. 29, Taliaferro Apr. 1, Egan Apr. 14, Hogg Oct. 19, Goodwin May 24, Campbell Oct. 11, Haller May 9, Cavalho Nov. 28, Dorough Apr. 15, Knowles Dec. 8, White Jan. 25, Fankhanel Jan. 1, Barnby et a1. Apr. 2, Glocker Mar. 9, Haggart, Jr Aug. 16, Gora Dec. 27, Pattle Aug. 1, Gora Apr. 10, Dryer July 8, Miller Ian. 20,
Maier Oct. 13,
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Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2841823A (en) * 1954-02-08 1958-07-08 Carroll H Van Hartesveldt Molding apparatus
US2864140A (en) * 1955-10-31 1958-12-16 Package Machinery Co Vacuum die casting means
US2962761A (en) * 1959-01-09 1960-12-06 Goshen Rubber Co Inc Apparatus for molding flashless rubber articles
US2976571A (en) * 1958-11-14 1961-03-28 Ernest P Moslo Mold venting structure
US2982999A (en) * 1955-04-18 1961-05-09 Federal Mogul Bower Bearings Method of molding shaft seals
US2999531A (en) * 1955-11-04 1961-09-12 Anchor Hocking Glass Corp Method and means for forming and inserting gasket blanks in closures
US3004297A (en) * 1958-08-12 1961-10-17 Anchor Hocking Glass Corp Method for forming a gasket
US3004298A (en) * 1957-02-11 1961-10-17 Federal Mogul Bower Bearings Method for making fluid seals
US3063097A (en) * 1959-12-04 1962-11-13 Chicago Rawhide Mfg Co Apparatus for forming seals
US3178792A (en) * 1963-03-01 1965-04-20 Bausch & Lomb Apparatus for hot pressing ceramic material
US3224616A (en) * 1963-11-20 1965-12-21 Roehr Metals & Plastics Compan Closure and method of making same
US3238566A (en) * 1964-09-28 1966-03-08 Resistance Welder Corp Apparatus for sealing in plastic forming machines
US3414938A (en) * 1968-02-15 1968-12-10 Hoosier Crown Corp Plastic processing system
US3485908A (en) * 1966-12-09 1969-12-23 Oliver Tire & Rubber Co Method for molding elongated elastomeric articles
US3490139A (en) * 1965-10-01 1970-01-20 Chicago Rawhide Mfg Co Seal and method of forming the same
EP0001011A1 (en) * 1977-08-24 1979-03-07 British Industrial Plastics Limited Improvements in or relating to moulding machines
EP0001012A1 (en) * 1977-08-24 1979-03-07 British Industrial Plastics Limited Improvements in or relating to moulding machines
US4234373A (en) * 1947-04-15 1980-11-18 General Dynamics Corporation, Pomona Division Method and apparatus for vacuum lamination of flex circuits
US4573894A (en) * 1984-11-23 1986-03-04 The B. F. Goodrich Company Apparatus for ventless tire molding
US4595553A (en) * 1984-11-23 1986-06-17 The B. F. Goodrich Company Method for ventless tire molding
US4597929A (en) * 1984-11-23 1986-07-01 The B. F. Goodrich Company Method for ventless tire molding and tire resulting therefrom
WO1993012982A1 (en) * 1991-12-26 1993-07-08 Precision Valve Corporation A dimpled gasket
EP0838326A1 (en) * 1996-10-24 1998-04-29 SACMI COOPERATIVA MECCANICI IMOLA S.c.r.l. Apparatus for molding a plastic seal inside a closure for closing a container
FR2756210A1 (en) * 1996-11-26 1998-05-29 Jenoptik Jena Gmbh DEVICE AND PROCESS FOR MOLDING STRUCTURES MADE BY MICROSYSTEM TECHNOLOGY
FR3027835A1 (en) * 2014-10-31 2016-05-06 Plastic Omnium Cie MOLD FOR THE MANUFACTURE OF A PLASTIC PART WITH AN OPTIMIZED SEALING SYSTEM
IT201900005038A1 (en) * 2019-04-03 2020-10-03 Pelliconi & C Spa CAP FOR CONTAINERS, PLANT, METHOD AND FORMING DEVICE FOR THE REALIZATION OF SAID CAP.

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US1373060A (en) * 1918-06-08 1921-03-29 American Can Co Process of preparing sanitary can ends
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US1956012A (en) * 1930-10-10 1934-04-24 Dewey And Almy Chem Comp Method of making alpha receptacle closure
US2096428A (en) * 1935-03-23 1937-10-19 Aluminum Co Of America Closure and receptacle
US2118080A (en) * 1933-06-24 1938-05-24 American Seal Kap Corp Molding mechanism
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US2181799A (en) * 1937-04-24 1939-11-28 Owens Illinois Glass Co Receptacle closure
US2238681A (en) * 1939-03-16 1941-04-15 Du Pont Container closure
US2304461A (en) * 1940-12-04 1942-12-08 Watson Stillman Co Injection molding apparatus
US2339827A (en) * 1940-04-24 1944-01-25 White Cap Co Closure cap and package
US2392238A (en) * 1943-03-12 1946-01-01 Crown Cork & Seal Co Cap
US2397589A (en) * 1943-05-01 1946-04-02 Owens Illinois Glass Co Container closure
US2437515A (en) * 1945-12-04 1948-03-09 Super Seal Container Corp Container closure
US2479350A (en) * 1947-10-03 1949-08-16 Jr John C Haggart Apparatus for molding reflector devices
US2492144A (en) * 1944-12-30 1949-12-27 Gora Lee Corp Cap for containers
US2516908A (en) * 1945-09-24 1950-08-01 American Can Co Apparatus for lining can ends
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US2602559A (en) * 1948-09-24 1952-07-08 Armstrong Cork Co Venting closure and liner therefor
US2626073A (en) * 1948-06-30 1953-01-20 Armstrong Cork Co Venting closure and liner therefor
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US304252A (en) * 1884-08-26 Gael behee
US1325056A (en) * 1919-12-16 Jar-closure
US1265808A (en) * 1916-04-13 1918-05-14 John Morrison Making brushes.
US1373060A (en) * 1918-06-08 1921-03-29 American Can Co Process of preparing sanitary can ends
US1488567A (en) * 1922-06-19 1924-04-01 Thomas L Taliaferro Hermetic closure for jars
US2158044A (en) * 1929-05-18 1939-05-09 Hygrade Sylvanla Corp Method of making contactor bases for electric lamps, tubes, and the like
US1956012A (en) * 1930-10-10 1934-04-24 Dewey And Almy Chem Comp Method of making alpha receptacle closure
US2118080A (en) * 1933-06-24 1938-05-24 American Seal Kap Corp Molding mechanism
US2096428A (en) * 1935-03-23 1937-10-19 Aluminum Co Of America Closure and receptacle
US2133019A (en) * 1936-03-26 1938-10-11 Aetna Rubber Company Mold
US2181799A (en) * 1937-04-24 1939-11-28 Owens Illinois Glass Co Receptacle closure
US2238681A (en) * 1939-03-16 1941-04-15 Du Pont Container closure
US2339827A (en) * 1940-04-24 1944-01-25 White Cap Co Closure cap and package
US2304461A (en) * 1940-12-04 1942-12-08 Watson Stillman Co Injection molding apparatus
US2392238A (en) * 1943-03-12 1946-01-01 Crown Cork & Seal Co Cap
US2397589A (en) * 1943-05-01 1946-04-02 Owens Illinois Glass Co Container closure
US2492144A (en) * 1944-12-30 1949-12-27 Gora Lee Corp Cap for containers
US2548305A (en) * 1945-07-26 1951-04-10 Gora Lee Corp Machine and method for making sealing closures
US2516908A (en) * 1945-09-24 1950-08-01 American Can Co Apparatus for lining can ends
US2437515A (en) * 1945-12-04 1948-03-09 Super Seal Container Corp Container closure
US2479350A (en) * 1947-10-03 1949-08-16 Jr John C Haggart Apparatus for molding reflector devices
US2626073A (en) * 1948-06-30 1953-01-20 Armstrong Cork Co Venting closure and liner therefor
US2602559A (en) * 1948-09-24 1952-07-08 Armstrong Cork Co Venting closure and liner therefor
US2654913A (en) * 1950-07-27 1953-10-13 Continental Can Co Art of making closure seals by molding and curing

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4234373A (en) * 1947-04-15 1980-11-18 General Dynamics Corporation, Pomona Division Method and apparatus for vacuum lamination of flex circuits
US2841823A (en) * 1954-02-08 1958-07-08 Carroll H Van Hartesveldt Molding apparatus
US2982999A (en) * 1955-04-18 1961-05-09 Federal Mogul Bower Bearings Method of molding shaft seals
US2864140A (en) * 1955-10-31 1958-12-16 Package Machinery Co Vacuum die casting means
US2999531A (en) * 1955-11-04 1961-09-12 Anchor Hocking Glass Corp Method and means for forming and inserting gasket blanks in closures
US3004298A (en) * 1957-02-11 1961-10-17 Federal Mogul Bower Bearings Method for making fluid seals
US3004297A (en) * 1958-08-12 1961-10-17 Anchor Hocking Glass Corp Method for forming a gasket
US2976571A (en) * 1958-11-14 1961-03-28 Ernest P Moslo Mold venting structure
US2962761A (en) * 1959-01-09 1960-12-06 Goshen Rubber Co Inc Apparatus for molding flashless rubber articles
US3063097A (en) * 1959-12-04 1962-11-13 Chicago Rawhide Mfg Co Apparatus for forming seals
US3178792A (en) * 1963-03-01 1965-04-20 Bausch & Lomb Apparatus for hot pressing ceramic material
US3224616A (en) * 1963-11-20 1965-12-21 Roehr Metals & Plastics Compan Closure and method of making same
US3238566A (en) * 1964-09-28 1966-03-08 Resistance Welder Corp Apparatus for sealing in plastic forming machines
US3490139A (en) * 1965-10-01 1970-01-20 Chicago Rawhide Mfg Co Seal and method of forming the same
US3485908A (en) * 1966-12-09 1969-12-23 Oliver Tire & Rubber Co Method for molding elongated elastomeric articles
US3414938A (en) * 1968-02-15 1968-12-10 Hoosier Crown Corp Plastic processing system
EP0001011A1 (en) * 1977-08-24 1979-03-07 British Industrial Plastics Limited Improvements in or relating to moulding machines
EP0001012A1 (en) * 1977-08-24 1979-03-07 British Industrial Plastics Limited Improvements in or relating to moulding machines
US4573894A (en) * 1984-11-23 1986-03-04 The B. F. Goodrich Company Apparatus for ventless tire molding
US4595553A (en) * 1984-11-23 1986-06-17 The B. F. Goodrich Company Method for ventless tire molding
US4597929A (en) * 1984-11-23 1986-07-01 The B. F. Goodrich Company Method for ventless tire molding and tire resulting therefrom
US5325985A (en) * 1991-12-26 1994-07-05 Precision Valve Corporation Gasket with a self-supporting protrusion
WO1993012982A1 (en) * 1991-12-26 1993-07-08 Precision Valve Corporation A dimpled gasket
EP0838326A1 (en) * 1996-10-24 1998-04-29 SACMI COOPERATIVA MECCANICI IMOLA S.c.r.l. Apparatus for molding a plastic seal inside a closure for closing a container
US6007315A (en) * 1996-10-24 1999-12-28 Sacmi Cooperative Meccanici Imola S.C.R.L. Apparatus for molding a plastic seal inside a closure for closing a container
FR2756210A1 (en) * 1996-11-26 1998-05-29 Jenoptik Jena Gmbh DEVICE AND PROCESS FOR MOLDING STRUCTURES MADE BY MICROSYSTEM TECHNOLOGY
FR3027835A1 (en) * 2014-10-31 2016-05-06 Plastic Omnium Cie MOLD FOR THE MANUFACTURE OF A PLASTIC PART WITH AN OPTIMIZED SEALING SYSTEM
WO2016066940A1 (en) * 2014-10-31 2016-05-06 Compagnie Plastic Omnium Mould for producing a part made from plastic materials, comprising an optimized sealing system
IT201900005038A1 (en) * 2019-04-03 2020-10-03 Pelliconi & C Spa CAP FOR CONTAINERS, PLANT, METHOD AND FORMING DEVICE FOR THE REALIZATION OF SAID CAP.
EP3722222A1 (en) * 2019-04-03 2020-10-14 Pelliconi&C. S.p.a. Cap for containers, plant, method and forming device for making said cap
US11866238B2 (en) 2019-04-03 2024-01-09 Pelliconi & C. S.P.A. Cap for containers, plant, method and forming device for making said cap

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