US3270904A - Press-on turn-off cap - Google Patents

Description

Sept. 6, 1966 c. N. FOSTER ETAL 3,270,994

IRESS-ON TURN-OFF CAP Filed may 21, 1964 2 sheets-sheet 1 INVENTORS CHARLES N. FOSTEQ ROBERT K. MQELQOY JOHN J. www

Sept 6, 1966 c. N. FOSTER ETAL 3270,@04

`PRESSON TURN-OFF CAP Filed May 2l, 1964 2 Sheets-Sheet 2 M m l Mul/Hmy 45 f 1 wmf 53 INVENTORS CHARLES N. FOSTERJ United States Patent O 3,270,904 PRESS-N TURN-DFF CAP Charles N. Foster, ak Park, Robert K. McElroy, Hinsdale, and .lohn J. Curry, Chicago, Ill., assignors to Continental Can Company, Inc., New York, NX., a corporation of New York Filed May 21, 1964, Ser. No. 369,092 20 Claims. (Cl. 21S- 43) This invention relates to a novel closure assembly and method of forming the same. More specifically, the present invention relates to a novel cap member adapted to be applied .to a container by a generally vertical pressing movement, with suitable means on the container rim co-operating with additional means formed in the cap after capping providing camming surfaces to permit easy removal of the cap by rotation.

A wide variety of cap designs are currently in use, serving a rather broad area of application. The press-on, pry-up or hook-off type of cap has found wide acceptance in the industry to form closure assemblies for soft drinks, catsup, baby food and the like. This design is highly desirable from the capping standpoint since relatively speaking, it is very easy to apply. In those applications wherein it is desirable to re-apply andv remove the caps several times, the pry-up or hook-off cap is not completely satisfactory from the consumer standpoint. Accordingly, in the latter applications rotatable closures such as lug and screw type caps are oftentimes used. Several disadvantages exist in rotatable closures including the requirement of more complex machinery and time to apply the closure initially. The material of rotatable closure shells is subjected to many stresses in local areas where the material of the shell encounters the co-operating container. This tends to cause distortions which eventually lead to stripping of threads on closures, or causing an imperfect seal to be formed with the resultant spoilage or loss of contents. Each type of closure vhas been satisfactory for a number of uses, however a definite need exists for a cap which may be easily applied, and yet be provided with suitable means to allow removal without the use of tools.

At the present time, one form of closure or cap exists which may be removed without the use of tools. In this type, the cap is distorted by pressing or squeezing, sothat the cap assumes a changed configuration and hence may be lifted off the container. An inherent disadvantage exists in this type of cap since when shifted or handled, the normal impacts to which they are subjected will cause them to prematurely spring or distort to become loose with the obvious consequences.

Obviously, if the desirable attributes or advantages of the various forms of caps could be combined in a single cap, the cost of forming a closure assembly would be maintained at a minimum and the closure would be easily removable to retain consumer confidence and good will. With this objective in mind, considerable `research and development time, etfort and funds have been directed toward seeking a satisfactory solution to this problem. It was concluded that the cap must be capable of being quickly applied with the simplest type of capping equipment, `and yet be easily removed without the use of tools and be capable 4of reapplication. In the initial capping operation, the requisite tightness must be had for complete reliability in the sealing gasket in order to insure protection of container contents.

The present invention was developed -as a result of these efforts, providing for a simple downward pressure during the initial application of the cap to form an effective seal with the container to which it is applied. With this type of method, the complicated machinery 3,270,904 Patented Sept. 6, 1966 formerly necessary to seal rotatable closures is eliminated while none of the disadvantages of the deforma-ble caps or caps that are hooked or pryed off are present.

The present invention includes an elastomeric or plastomeric lining extending around the inner perimetral surface of the cap which serves a dual function. First, the lining forms a gasket co-operating with the container and second, provides a cam surface in the form of thread-like means for co-operation with suitable thread means on the container to permit rem-oval by rotation. Substantial benefits are derived from the present construction in the form of a better container seal 'being formed. The stresses in the cap flange are evenly distributed thereby permitting the use of lighter materials with .the obvious reflection in overall cost. This is permissible because one set of threads are formed in the plastomeric material and will accommodate irregularities in the co-operating container threads without appreciable distortion of the co-operating cap. Even though the cap is of thinner metal than is commonplace, it is' capable of withstanding more abuse in the form of shocks and impacts largely because of the small distance separating the cap from the container.

The generous length of the seal provides a -barrier to the permeation of gases such as oxygen in addition to maintaining a hermetic seal to protect the contents against contamination and loss. In addition, with a seal of extended length, infestation of mold or insects between the cap and container is prevented. The thinness of the seal, due to the close spacing of the cap and co-operating portion of the container, as well as the length serves to keep oxygen permeation at a minimum.

More specifically, the present invention utilizes a cap member having a generally at top portion with a generally frusto-conical depending ange or skirt portion. This type of configuration would normally be thought to be undesirable from the standpoint of cap handling and sorting, since logically it would seem that the caps would have a tendency to nest making cap handling dificult. In the present instance, however, the depending ange or skirt of the cap may be distorted slightly because of its thin construction, so that it will not nest, and thereafter can be conveniently reformed during application to a container to force it back to the required shape. Many other advantages are available with the use of the instant invention as will become apparent in the presentation of the more prominent objects to be achieved and the description of the embodiments to follow.

It is therefore an object of this invention to provide a new and improved closure assembly which may be formed with -simple equipment.

It is a further object `of this invention to provide a novel cap construction for application to a container, which is uniquely different from the prior art in that it is sealed by forcing it downwardly on the container without intentional rotation, and thereafter means is formed in the cap to co-operate with suitable means on the container to permit easy removal by rotation.

It is a further object of this invention to provide a cap construction having a seal which prevents infestation of mold or insects Ibetween the `cap and container.

It is a further object of this invention to provide a new and improved closure assembly which will withstand extraordinary abuse and handling while providing a secure hermetic seal forming a barrier to the permeation of gases which could contaminate the contents.

It is a further object of this invention to provide a new and improved method of forming a closure assembly including applying a cap member to a container by pressing the former downwardly on the latter and thereafter forming suitable means to assist in removal by rotation.

It is a further object of this invention to provide a new and improved cap member which is inexpensive to manufacture and apply to a wide variety of containers.

It is a further object of this invention to provide a new and improved closure assembly including a cap member `having a moldable material therein which forms means to effect removal by rotation as well as providing a permanent seal to protect the container contents.

Further and fuller objects will become readily apparent when reference is made to the accompanying drawings wherein:

FIG. 1 is a fragmentary side elevational view of a container having a cap of the present invention carried in a capping head and positioned above t-he container for application thereto;

FIG. 2 is an enlarged half section taken generally along the lines 2 2 of FIG. 1 after the cap has been applied;

FIG. 3 is a view similar to FIG. 2 taken along the lines 3-3 of FIG. 1 after application of the cap;

FIG. 4 is an enlarged fragmentary elevational view of a container with a modified form of cap member in section positioned above the container preparatory to cap- 111s; p FIG. 5 is an enlarged half section of the container of FIG. 4 taken along the lines 5-5 of FIG. 4 after the cap has been applied;

FIG. 6 is a fragmentary elevational view of a container with a cap member in section positioned for application to the container; and

FIG. 7 is an enlarged half section taken along the lines 7-7 of FIG. 6 after application of the cap to the container.

FIGS. l-3 show one form of the present invention 1ncluding a container member 10 having a continuous rim portion 11 of generally frusto-conical shape terminating in a neck 12 of reduced diameter at the lower end and a top 13 defining a container mouth 14 at the upper end. A cap member 15 is illustrated in section having a generally at central top portion 16 for covering the container mouth 14, with marginal edge portions being defined by a rim relief groove 17 which co-operates with the top of the container rim 13. The cap 15 further` includes a depending flange portion 18 terminating at its lower end in a curled edge portion 19 lending stiffness to the flange. The depending ange is of frusto-conical conguration and is adapted to fit over the container rim portion 11 in the manner shown in FIGS. 2 and 3.

A series of discontinuous tread means indicated generally at 20 are provided on the container rim 11 in the form of cutaway portions having the lowermost edge portions 21 extending in a slightly angular direction with respect to the central axis of the container. The lower edge portion 21 defines a cam-like surface when a co-operating surface is fitted within the same as will be seen hereinafter upon a more detailed description of FIG. 2. The thread means 20 has the bottom 22 formed of a generally cylindrical configuration extending longitudinally upward from the lower edge portion and merging with the inwardly tapering outer surface of the continuous rim portion 11. The cap member 15 is of generally cup shape design, inverted in the manner shown in FIG. 1 for applcation to the container 10.

The container relief groove 17 and the depending flange portion on the cap member 15 are provided with a coating of elastomeric or plastomeric material indicated generally at 23 for purposes to become apparent. As seen in FIG. 1, the cap member 15 is received within a capping assembly comprising an anvil shown fragmentarily at 24 having a coaxial punch 25 extending downwardly into close proximity with the curl 19 on the depending flange 18.

The plastomeric material 23 shown in the cross sectional view of FIG. 1 is deposited in a manner to provide generally, a smooth continuous surface generally parallel to the surface of the depending ange 18 of the cap member 15. In applying a cap the anvil member 24 forces the cap downwardly on t-he container 10 covering the rim portion and bringing the plastomeric material 23 into overlying relationship with the thread means 20. As seen in FIG. 2, the plastomeric material 23 has flowed into the thread means 20 to provide a continuous barrier from adjacent the neck 12 over the top portion 13 of the container 10. After the cap has been seated on the rim 11, the punch 25 may reform the curl 19 to engage the neck portion a slight amount as shown to retain the cap member in place.

The reforming operation by means of the punch 25 may be omitted if desired, since substantial contact between the plastomeric material 23, thread means 20 and the uninterrupted sections of the rim portion 11 exists, devolping sufiicient holding power to hold the cap member to the container 10. under a vacuum, atmospheric pressure acting on t-he top 16 of the cap member 15 will also assist in maintaining the cap positioned. In any event, bending of the curl 19 during the reforming operation of the lightweight metal is of such magnitude that it can be overcome as the cap is conveniently moved by rotation. This is accomplished by means of a thread forming embossment 26 in the plastomeric material which takes a tno-operating shape with the cam surface 21 on the thread means 20 in the rim portion 11, the camming action occuring on relative rotation between the container 10 and the cap 15. The co-operating cam surfaces lift the cap member upwardly springing the lightweight reformed curled portion 19 outA wardly to allow ready removal of the cap.

In FIG. 3, t-he curl has not been reformed, thus illustrating how the cap would appear in those applications wherein reforming is not required. The rather generous extent of the sealing portion is evident in FIG. 3, extending from inside the mouth portion 14 over the top 13 down to a point closely adjacent the neck portion 12. The particular method whereby the thread forming is accomplished will be discussed hereinafter since it is generally applicable to all the embodiments shown.

FIG. 4 illustrates a related but modified form of closure assembly including a cap member 27 having a top portion 28 and rim relief groove 29. The depending ange on the cap member 27 extends from the bottom of the relief groove 29 in an outwardly flaring or frustoconical manner as at 30, merging smoothly with a generally cylindrical lower section 31 which terminates in a curl 32. In the embodiment of FIG. 4, the curl is formed oppositely to that shown in FIGS. 1-3 illustrating the versatility of the design of the cap construction. A fragmentary portion of the container to be capped is illustrated at 33 having a neck portion 34 of reduced diameter which flares outward to merge with a generally frusto-conical rim portion 35. A series of discontinuous thread means 36 are embossed on the outer surface of the generally frusto-conical rim section extending in slightly vertical overlapping engagement more clearly seen in the enlarged cross sectional view of FIG. 5.

In the cross sectional View of FIG. 5, the cap 27 has been applied to the container rim 35, and thereafter the plastomeric material 37 takes a conforming configuration to form a hermetic seal and thread means co-operating with the embossments 36. Hardening of the plastomeric material is effected in an appropriate manner to form rigid thread grooves for camming co-operation with the raised threads 36 on the container rim 35. The junction between the frusto-conical surface 30 and cylindrical surface 31 yoccurs over the lower thread 36 to provide a portion of increased thickness. If desired, the curled portion 32 may be reformed to engage the neck portion 34 as in the FIG. 2 embodiment.

FIGS. 6 and 7 illustrate still another embodiment of the invention including a cap member 40 having the usual substantially flat top portion 41. A rim relief groove 42 may be provided at the marginal edges of the cap member if desired. The depending flange portion of the cap In the case of products packaged 40 is somewhat different than the prior embodiments having a generally straight cylindrical section 43 forming one side of the rim relief groove 42 and ex-tending downwardly to merge with an outwardly flaring frusto-conical section 44. An inwardly curled portion 46 is formed at the lower end of the cylindrical section 45 to rigidity the depending flange portion. Below the cap member 40 in FIG. 6, a container 47 is shown fragmentarily, having a neck portion 48 and rim portion 49 defining the container mouth. A modified form of thread means 50 formed yon the rim 49, 'being of the embossed variety. The thread means 50 are of the continuous rtype and merge smoothly at their lower end with a cylindrical portion 51 of increased diameter intermediate the neck 48 and rim 49.

The modified form of depending flange in the cap 40 is varied in order to change the amount of plastomeric compound 52 which will ultimately be disposed between the outer shell of the cap member 40 and the container rim 49. The plastomeric material 52 extends the full length of the depending flange flowing into the curl 46 slightly to cover the raw edge 53. This serves to protect the raw edge from contact with corrosive materials which cause rusting and discoloration of the cap, making it unsightly and unacceptable to discerning consumers. The use of a long length plastomeric material 52 allows the top and seal portion formed thereby to withstand extremely severe blows without a loss of the hermetic seal between the cap 40 and the container 47.

When the cap 40 is applied to the container 47 the plastic compound assumes the configuration shown in FIG. 7 to form thread means 54 for co-operation with the embossed threads 50 on the container rim 49. The generous length of the sealing areas not only protects the container contents from gas permeation land loss of vacuum within the container but also serves as a cushion to absorb and dampen impacts applied to the cap during shifting and handling. With the space between the cap and container filled, infestation of mold, insects and the like which may be drawn into the container upon opening, is prevented. The cap 40 may be applied in a vertical manner similar to that illustrated in FIG. l and described in conneution =with FIG. 4, and thereafter removed by rotation whereby the thread means 54 `co-operates with the thread means 50 on the container 47 to provide the sufficient lift to remove the cap 40 therefrom.

In each of the embodiments shown, a plasticized polyvinyl chloride plastisol containing small discrete bubbles of gas which provide a compressible volume to compensate for various volumes encountered in difieren-t areas between the closure shell and the container-s is preferred. These materials are oftentimes described in the art as puffed or foamed plastisols and the method of manufacturing the same is also well known in the art.

Other lclasses of plastomeric or elastomeric materials may be used if the properties are suited for the present applications, For example, rubber, synthetic rubber, foam polyurethane or foam polyethylene or the like which exhibit the required flow and set properties could be used. In the method about to be described where heat is employed, each of the softening materials, such as plasticized polyvinyl chloride or polyethylene or hot melts could well form the basis of the compound.

The invention as described above is readily adaptable to a number of different types of container sealing and packaging processes. Included among these are various products wherein the tempera-tures at the time of sealing would be fairly high in order to provide various vacuums in the container head space at cooling. Others would include pasturizing at atmospheric pressure or processing in retorts or the like. IUnder any one of these applications, the moldable material or plastomeric compound must be selected to meet the requirements of the particular type of sealing to be done.

Where seals are to be formed a-t room temperature, the plastomeric compound should be selected to provide the requisite cold flow or high permanent set characteristics necessary for good forming. As noted previously, these may be taken from the class of rubber, synthetic rubber or from such materials as foamed polyurethane, foamed polyethylene -or similar plastics which exhibit the required ow and set properties. When heat is employed, heat softening materials such as plasticized polyvinyl chloride, polyethylene or hot melts may be used to form the basis of the compound.

It is obvious that the particular shape of the cap depending ange will vary with the compound and the degree of adhesion to the cap member, since the compound must be sufficiently adhesive to allow a direct press-on type application, and thereafter be rm or rigid enough to provide a co-operating cam surface to project the capupwardly on rotation. Where desirable, the curled portion may be reformed into the neck of the container to provide additional gripping means. Under these circumstances, the plastomeric or elastomeric material must have a suiicient shear modulus to overcome the gripping action of the curled portion when removal of the cap member is effected.

As pointed out previously, the cap member is formed of metal, however, suitable other materials could be used with equal facility and it is not intended that the present application be restricted to metal alone. The higher the modulus of the plastomeric material, the shallower the camming projection may be made. Obviously, this is also true as the adhesion of the sealing material to the closure shell improves and friction between the plastic material and the container is reduced.

If opposing requirements for the gasket and the thread forming portion of the moldable component were encountered, it is contemplated that the gasket portion cooperating with the to-p of the rim could be of a different material suitable for good sealing action.

It is to be understood that the foregoing is a description of the preferred embodiments of the invention and that various modifications may be made without departing from its spirit and scope.

We claim:

1. The method of capping and sealing a container with a cap, each of said cap and container having means thereon to cam said cap upwardly upon rotation thereof during removal from said container, comprising the steps of providing a cap having a depending flange portion around the marginal edges thereof, depositing a plastic-like material at least around said marginal edges of said cap interiorly thereof, pressing said cap onto said container with a generally vertical motion, and causing said plasticlike material to ow and set thereby forming a cam means for co-operating with cam means on said container to assist in camming said cap upwardly on relative rotation between said cap and container.

2. The method of capping a container in a hermetically sealed manner, said container having a cap receiving rim portion with thread means thereon, said method of capping comprising the steps of providing a cap member having a generally flat top portion and a depending flange portion, coating at least said depending flange portion on the interior with a plastic-like material, pressing said cap member over said rim portion in a downwardly manner without intentional rotation so that said plastic-like material extends above and below said thread means, sealing said cap member under 4proper conditions so that said plastic-like material vflows and sets to form a hardened co-operating thread means on said cap member for co-operation with said thread means on said container rim portion whereby said cap member is removable by rotation.

3. The method of claim 2 wherein said sealing step comprises heating at least one of said container and said cap member.`

4. The method of claim 2 wherein said container has a neck portion below said rim -portion and further including the step of deforming a portion of said depend` ing flange into said neck portion prior to complete seal ing of said plastic-like material.

5. The method of capping a container having a neck and a rim portion with thread means thereon, comprising the steps of providing a cap .member adapted to fit over said rim portion, coating the interior marginal edges of said cap member with a plastic-like material, lpressing said cap member on said container rim so that a portion of said plastic-like material is positioned adjacent said thread means and adjacent said rim portion, and causing said plastic-like material to flow around said thread means on said rim portion to form co-operating thread means in said plastic-like material whereby said cap member may be removed by rotation.

6. The method of claim including the step of deforming a portion of said cap member into said neck.

7. A press-on turn-olf closure assembly comprising in combination a container having a rim portion, thread forming means on said rim portion, a cap having a depending ange portion overlying and surrounding said rim portion, a plastic-like material interposed between said cap and said rim portion at least in the region of said thread forming means to form a continuous seal of long length, said cap being adapted to be applied to said container in a vertical downward presson manner without intentional rotation, and izo-operating thread means formed in said plastic-like material after application of said cap to said rim whereby said cap may be removed by rotation with said co-operating thread means providing co-operating lifting cam surfaces.

8. The closure assembly of claim 7 wherein said thread forming means on said rim portion comprises a series of embossments.

9. The closure assembly of claim 7 wherein an upper part of said rim portion is of frusto-conical configuration and said depending flange portion overlying said upper part is of a complementary configuration.

10. The closure assembly of claim 9 wherein a lower part of said rim portion is of cylindrical configuration and a lower part of said depending iiange portion is of complementary configuration, said plastic-like material substantially filling the space between the opposed cylindrical and truste-conical surfaces.

11. A press-on turn-off closure assembly comprising, a container having a continuous rim portion detining a container mouth, a cap coveriing said mouth and having a continuous depending ange overlying said rim portion, a plastic-like material between said rim portion and said flange, a series of thread-like depressions in said rim portion, and a series of complementary thread-like embossments formed in said plastic-like material after said cap is applied to said rim.

12. The closure assembly of claim 11 wherein said rim portion is of generally frusto-conical shape and said depending flange is of complementary shape.

13. The closure assembly of claim 11 wherein said thread-like depressions in said plastic-like material in said rim include a bottom wall portion of generally cylindrical section.

14. A closure assembly comprising a container having a rim portion, said rim portion having a part thereof of frusto-conical shape, a cap member having a generally liat top portion adapted to cover said container, a depending flange portion spaced slightly from said rim portion of said container, a plastic-like material interposed between said rim portion and said depending flange forming a container seal, thread means on said rim portion co-operating with said plastic-like material to form cooperating thread means in said plastic-like material after press-on application of said cap member tosaid container whereby said cap may be removed by rotation relative to said container.

15. The closure assembly of claim 14 wherein said depending llange on said cap member has the lower portion thereof formed of a cylindrical section, said cylindrical section merging with said frusto-conical section radially outwardly of said thread means to provide a region of increased thickness.

16. The closure assembly of claim 14 wherein said rim portion terminates at its lower end in a neck of reduced diameter and a portion of said depending angeis deformed into said neck..

17. A closure assembly comprising a container having a rim portion forming a container mouth, a cap member having a generally flat top portion covering said container mouth, a depending flange portion of generally frusto-conical shape on said cap member and extending downwardly over said rim portion and slightly spaced therefrom, a plastic-like material extending from said container mouth downwardly to fill the space between said depending tiange portion and said rim portion to form a continuous hermetic seal, and thread means on said rim portion, said thread means being substantially covered by said plastic-like material and further being slightly spaced from said depending flange portion, said plasticlike material being adhesivcly joined to said cap member and hardenable to form co-operating thread means in said cap member after press-on application to said container whereby said cap member is removable by rotation relative to said container.

18. A cap member for press-on applications to a container comprising a generally ilat top portion and a continuous depending flange, said depending ange having a portion thereof aring outwardly as it extends from said top portion, and a layer of plastic-like material covering a portion of the underside of said top portion and extending downwardly along said depending ange, said plastic-like material adapted to ow around thread means provided on said container to form thread means in said cap member to permit removal by rotation.

19. The cap member of claim 18 wherein said depending liange is deformed slightly to prevent nesting with other cap members and said flange being reformed on application to said container.

20. The closure assembly of claim 18 wherein said plastic-like material is provided with discrete bubbles permitting slight compression to permit press-on application and continuous hermetic sealing.

References Cited by the Examiner UNITED STATES PATENTS 802,383 10/1905 Fenn 215-43 2,131,319 9/1938 Greenholtz et al. 21S-*93.1 2,961,109 11/1960 Podesta 21S-39 LOUIS G. MANCENE, Primary Examiner. THERON E. CONDON, Examiner. J. B. MARBERT, Assistant Examiner.

Claims (1)

1. THE METHOD OF CAPPING AND SEALING A CONTAINER WITH A CAP, EACH OF SAID CAP AND CONTAINER HAVING MEANS THEREON TO CAM SAID CAP UPWARDLY UPON ROTATION THEREOF DURING REMOVAL FROM SAID CONTAINER, COMPRISING THE STEPS OF PROVIDING A CAP HAVING A DEPENDING FLANGE PORTION AROUND THE MARGINAL EDGES THEREOF, DEPOSITING A PLASTIC-LIKE MATERIAL AT LEAST AROUND SAID MARGINAL EDGES OF SAID CAP INTERIORLY THEREOF, PRESSING SAID CAP ONTO SAID CONTAINER WITH A GENERALLY VERTICAL MOTION, AND CAUSING SAID PLASTICLIKE MATERIAL TO FLOW AND SET THEREBY FORMING A CAM MEANS FOR CO-OPERATING WITH CAM MEANS ON SAID CONTAINER TO ASSIST IN CAMMING SAID CAP UPWARDLY ON RELATIVE ROTATION BETWEEN SAID CAP AND CONTAINER.

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