US3529648A - Top-to-container snap lock - Google Patents

Description

Sept- 22, 1970 B'. M. BARTlLsoN` 3,529,648

TOP-TO-CONTAINER SNAP LOCK Filed Nov. 25, 1968 2 sheets-sheet 1 Sept. 22, 1970 B. M. BARTILSON 3,529,648

v ToP-To-CONTAINER SNAP LOCK Filed Nov. 25, 1968 2 sheets-snm, f,

a #25AM United States Patent O1 lice 3,529,648 Patented Sept. 22, 1970 3,529,648 TOP-TO-CONTAINER SNAP LOCK Benjamin M. Bartilson, Columbus, Ohio, assignor to Morton International, Inc., Chicago, Ill., a corporation of Delaware Filed Nov. 25, 1968, Ser. No. 778,391 Int. Cl. B65d 39/04, 41/18 U.S. Cl. 150-.5 5 Claims ABSTRACT OF THE DISCLOSURE A plastic top closure is nonremovably and sealingly snap fitted to the registering open end of a plastic container by cooperating structures on the two components. The open end of the container has an inwardly-directed peripheral collar, upstanding lip and a plurality of discrete tabs integrally formed thereon. The top closure has an integrally-formed depending inner flange with an outwardly directed rim or shoulder adjacent the lower extremity which interlits in snap locking engagement with the tabs of the container. An integrally-formed depending outer flange registers with the upper wall of the container and engages the collar and the lip thereof whereby the tabs of the container and the shoulder of the inner flange are exteriorly inaccessible.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to a snap-lock combination for joining a plastic container and its top closure. More specifically it relates to a low cost, easily-moldable, readily-assembled snap-lock combination for joining a plastic container and closure which results in a leak proof, high strength, sanitary joint which, once assembled, can not be non-destructively disassembled.

For convenience herein, the invention will be described with particular reference to a salt (sodium chloride) package comprising a molded plastic container for the salt and a plastic top with dispensing apertures snap locked thereto. It should be understood, however, that the invention is not limited thereto and can be embodied in the form of plastic snap locks for a wide variety of packages, but, most advantageously, for packages of particulate solids, e.g., various condiments in granular form, granular sugar, granular foodstuffs and other edible and non-edible granular substances.

DESCRIPTION OF THE PRIOR ART The packaging of very low cost products such as salt presents a number of problems which have not been adequately coped with by prior art structures. One of these problems is the requirement of providing at extremely low cost a means of positively locking a plastic cover member to the container so that it can not be disassembled for refilling or for other purposes. The assembly must also be leak proof and of high structural strength despite having relatively thin wall thicknesses. While some prior art structures may have some of the desired functional attributes, they did not lend themselves to high speed, low cost molding techniques and simple assembly procedures. Other prior-art devices may have met the cost requirement, but they did not have the requisite positive locking and positive sealing features and/ or were not acceptable from aesthetic, sanitary or other standpoints.

It is therefore an object of the present invention to provide a low cost, easily moldable and readily assembled top-to-container plastic locking assembly. It is a more specilic object of the presentl invention to provide a low cost, integrally molded top-to-container locking assembly which is non-removable once assembled, and which otherwise positively seals the top to the container. It is another object of the present invention to provide such a locking assembly which features a plurality of positive seals between the interior of the container and the exterior thereof.

It is another object of the present invention to provide such locking assembly of relatively thin wall thicknesses and yet of relatively high structural strength and rigidity. It is still another object to provide a positivelylocked and sealed top-to-container combination which meets high aesthetic and sanitary standards. These and other objects of the present invention will become apparent as a detailed description proceeds.

SUMMARY OF THE INVENTION In brief, these objects are achieved in a particular embodiment by the container and closure combination of the present invention. The container portion of the combination comprises a container body and an inwardly directed peripheral collar integrally formed on at least one open end of the container body. In a specific embodiment the container body is molded with one end closed (the bottom) and the opposite end open (the top). An upstanding lip is integrally molded on the inner extremity of the aforesaid peripheral collar and has on its upper extremity a plurality of integrally molded discrete tabs with the free ends of the tabs inwardly, and generally radially, disposed. The tabs preferably are scored so as to produce flexure prone lines thereon.

The closure or top portion of the combination comprises a downwardly depending inner flange integrally molded on the general flat closure, which flange interts into the container body so as to resiliently flex the tabs downwardly. This inner flange has an outwardly directed shoulder adjacent the lower extremity, which, upon assembly is disposed in snug locking engagement with the free ends of the downwardly flexed tabs. The closure also has a downwardly depending outer flange which registers with the upper exposed wall of the container in overlying relationship to the aforesaid collar and lip. Lower portions of the outer flange engage upper surfaces of the collar and outer surfaces of the lip to seal the structure.

Once assembled, the vital elements of this novel snap lock combination are inaccessible from the exterior. This feature, in combination with the reverse wall snap-lock construction and related structure, as hereinafter discussed, prevents the nondestructive removal of the cover from the container. Further details of the inventive combination are set forth in connection with the description of preferred embodiments.

Because of recognized advantages, the structure of the present invention is molded as a unitary structure in plastic. The selected plastic should be readily moldable by conventional low cost techniques, c g., injection molding and blow molding, and should preferably have high strength, reasonable resilience and suflicient body to maintain shape under normal usage. It should also be inert, free from objectionable odors, and should otherwise meet structural, sanitary and aesthetic requirements.

Suitable plastics may include, but are not limited to, polyethylenes, polypropylenes, polyamides, acetate-butyrate copolymers, polyvinyl chloride polymers and copolymers, polystyrene, and compatible combinations thereof, preferably polyethylenes and/ or polypropylenes. The plastic may also contain necessary or desirable additives, such as dyes, plasticizers, extenders, and the like, as those skilled in the plastic molding art will recognize. In the specific embodiments hereinafter set forth, the container top is injection molded from injection-molding grade, high density polyethylene having a density of about .95, and the salt container on which it is snap locked is blow- 3 molded from blow-molding grade high-density polyethylene having a density of about .96.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be more clearly understood from the following detailed description of specic embodiments read in conjunction with the accompanying drawings wherein:

FI-G. 1 is a fragmentary side elevation view showing an assembled salt package of the type which advantageously utilizes the top-to-container snap lock of the present invention;

FIG. 2 is an overhead plan view of the salt package of FIG. l;

FIG. 3 is an enlarged section view along the line 3 3 of FIG. 2;

FIGS. 4 and 5 are overhead plan views and fragmentary side elevation views, respectively, of the salt package of FIG. 1 before assembly of the top closure thereon;

FIG. 6 is an enlarged fragmentary section view on the line 6-6 of FIG. 4;

FIG. 7 is a still-further enlarged fragmentary section View similar to FIG. 6 but of another embodiment;

FIG. 8 is an enlarged section view of the top and container showing the snap lock combination of FIGS. 3-6 as it is being assembled;

FIG. 9 is a View similar to FIG. 8 showing the snap lock combination after assembly; and

FIG. l is a fragmentary section view similar to FIG. 9 but of another embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIGS. l and 2, a fragmentarily illustrated salt container 10 with an integrally-molded bottom (not shown) and an opposed open end is closed by means of closure top 12 along seam line 14. Top 12 may have a plurality of openings therethrough, e.g., pouring spout opening 16 and sprinkler opening 18, in which pouring spout closure combination 20 and sprinkler-closure cornbination 22 may be integrally molded, as shown in FIG. 3.

Since the number and type openings and the pouring or sprinkling devices therein are not, per se, the present invention, they are not described herein in detail. Detailed descriptions of such devices are, for example, set forth in the copending applications of Albert Yochim, Ser. No. 766,720 filed Oct. 1l, 1968, and entitled, Dispensing Apparatus; of Benjamin M. Bartilson and Harold E. Trumbull, No. 778,562 led contemporaneously herewith and entitled, Plastic Container Top With Combination Closure and Sprinkler; of Maynard E. Nyquist, Ser. No. 778,390 led contemporaneously herewith and entitled, A Plastic Container Top With Combination Closure and Sprinkler; and of Robert H. Jordan and Robert F. Boldt, Ser. No. 778,463 tiled contemporaneously herewith and entitled, Dispensing Grid.

Container 10 comprises container body 24 which is hollow and may be blow molded as a unitary structure with the aforementioned closed bottom and open top, the frustoconical sides being shown fragmentarily in the interest of drawing economy. At the open end, inwardly-directed annular collar 26 terminates in an upstanding lip 28, as can be observed in FIGS. 3-10. A plurality of discrete tabs 30 are molded adjacent the upper extremity of lip 28 with the free ends 32 thereof being disposed radially inwardly.

Tabs 30 may be scored or otherwise cut or indented on the upper or lower surfaces thereof adjacent upstanding lip 28 so as to create thinned or flexure prone areas for ease and accuracy of flexure upon assembly, as will hereinafter become apparent. In FIGS. 4, 8, 9 and l0, interrupted score lines 34 are shown on the upper surfaces of tabs 30. Tabs 30 may be molded so as to be horizontally disposed prior to assembly, as shown in FIG. 7, or inclined slightly downwardly as shown in FIGS. 6 and 8. If

molded horizontally, the tabs may be tilted downwardly by the aforementioned scoring.

The free ends 32 of tabs 30 are flexed downwardly and outwardly during assembly of container 10 and top 12 by the lower extremity of downwardly depending inner ange 36 which is integrally molded on the lower side of top 12. The assembling of the two structures is best illustrated in FIGS. S and 9 and illustrates the reverse Wall construction whereby tensile forces tending to separate container 10 and cover 12 are resisted by compressive forces in tabs 30.

The dimensions of ange 36 and tabs 30 are related so that free ends 32 snap into place over the upper surfaces of outwardly directed shoulder 38 adjacent the lower extremity of ange 36 when top 12 is forceably interfitted over and into container 10. The geometry is such that upon release of the assembly forces, which may momentarily distort the two structures while free ends 32 are snapping into place over shoulder 38, the two structures are snugly and nonremovably joined. The proper exure of tabs 30 to obtain the desired intert and snap lock may optionally be assured by the llexure proneness induced by score lines 34.

The only fway of nondestructively separating the two structures would be flex tabs 30 and flange 36 relative to one another whereby free ends 32 are released from shoulder 38. This is effectively prevented by isolating or rendering inaccessible the snap lock by means of downwardly (and outwardly) depending outer flange 40, the exterior surface of which registers with the outer surfaces of container 10 to form a smooth continuous wall interrupted only by the ne line of seam 14. The lower surfaces of outer flange 40 engage the registering upper outer surfaces of collar 26 along seam 14. Inner surfaces of outer flange 40 also engage outer surfaces of lip 28, as can best be seen in the embodiments of FIGS. 9 and 10.

In FIG. 9, outer ange 40 is bifurcated so as to form, in effect, spaced concentric sections or inner and outer rings 40a and 40b. The lower surface of section 40a engages collar 26; the inner surface of section 4Gb engages the outer surface of lip 28. In FIG. 10, outer ange 40 is not bifurcated but, instead, the geometry is such that the inner surface engages the upper extremity of lip 28 along chamfered portion 28a.

It should be noted' that the interrelationship of the components of the present structure, once assembled, provides substantial rigidity and strength, even if molded with relatively-thin plastic walls, e.g., about 25-50 mils. Thus, for example, manual pressure exerted substantially perpendicular to curved ange 40 of top 12 is counteracted by the normal rigidity of the convex curvature thereof, the stiifening provided by the web constituting the upper surface of top 12, the reaction of collar 26 against the lower surfaces of ange 40, the reaction of lip 28 against the inner surfaces of ange 40, all in turn being supported indirectly or directly by the reaction of the free ends of tabs 32 against shoulder 38 of inner flange 36, and the enhanced strength of container 10 inherent in its generally cylindrical closed-end design.

The nonremovability aspect of the present design is further enhanced by the disposition of the snap lock and the relationship of seam 14 and lip 28. If a knife blade or similar thin instrument is forced between collar 26 and outer flange 40, lip 28 prevents it from reaching either tabs 30 or ange 36.

The fact that tabs 30 are many in number, i.e., typically 5 to 12 in a 90 arc, and discrete, i.e., have separating slits in the plastic between each tab as can best be seen in FIGS. 4 and 6, also enhances the nonremovability aspect. If a hook were inserted through the apertures of either pouring spout closure 20 or sprinkler-closure 22 for pulling or deflecting a portion of flange 36 radially inwardly away from the tabs, the discrete mounting of the tabs and their natural resilience permit those in that area to follow the deflected ilange so that no release occurs. The inaccessibility of shoulder 38 and free ends 32 from either seam 14 or the apertures in the upper web of top 12 thus further enhances nonremovability.

'Ihe smoothness of the exterior walls of container wall 14 and flange 40 and the smoothness of the juncture at seam 14, combined with the nonremovable lock, prevent, of course, even the inadvertent destructive or nondestructive removal of top l12. These features also enhance the aesthetic appearance of the structure.

The various interengaging surfaces also effectively seal container and top 12 against undesired salt leakage via seal 14. Thus, in practice, tabs 30 substantially prevent any undesired flow of particulates into void space 42, the slits between the individual tabs generally being too narrow to permit passage of particulates therebetween. If any sifting of line particles into void space 42 occurs, it is blocked from the outside by the seal formed by the engagement of the inner surface of outer ange 40 and outer surface of lip 28. It is further sealed by the engagement of lower portions of outer flange 40 and the upper surface of collar 26. In fact, because of the multiple seals, the seal provided by tabs 30 may not be necessary in all embodiments. Thus, tabs 30 need not be continuously disposed around the periphery of the opening but could be in spaced relation from one another or in a plurality of spaced series.

A significant attribute of the present construction is that it can be produced by conventional low cost molding techniques. Thus, for example, container 12 can be blow moldeduemploying needle blowing techniques disclosed in E. E. Mills U.S. Pat. 2,579,390, incorporated here by reference, and a parison or extruded tube of high density polyethylene. The blow dome at the top can be guillotined to produce an open-ended container similar to that of FIG. 4, except for the lack of radial slits, the optional score marks, and accuratized circular opening. The circular opening can be accuratized (rendered substantially circular and smoothed) and the slits and score marks `added in a one-step finishing operation by a single in and out operation of a special tool. Top 12 can, for example, be injection molded fromhigh density polyethylene in a simple two section mold, the molding configuration and technique therefor being described, for example, in the aforesaid copending applications of Messrs. Yochim, Nyquist and Bartilson-Trumbull.

While the container opening depicted in the drawings is generally circular except for the pouring spout projection, it should be understood that the invention is not limited thereto. Other curved, oval, rectilinear and equivalent- Shaped openings (or combinations thereof) may also be employed as container or top design may dictate.

Since the pouring and sprinkling structures which are integrally molded as part of the top are not, as aforementioned, the subject matter of the present invention, the modifications necessary to incorporate such structures are not treated in detail herein and are considered within the skill of the art in the light of the present disclosure. Suffice it to say, for example, that the modifications shown at the right of FIGS. 8 and 9 complement the snap-lock combination so as not to adversely affect the nonremovability feature, the desired positive seal against leakage and other features of the present invention.

From the above description it is apparent that the objects of the present invention have been achieved. While only certain embodiments have been illustrated, many alternative modifications will be apparent from the above description to those skilled in the art. These and other alternatives are considered within the spirit and scope of the present invention, and coverage thereof is intended by this application.

Having described the invention, what is claimed is:

1. In a plastic container and closure assembly having a tiexible wall container body with an opening closed by a closure member, the combination which comprises:

(a) an inwardly directed peripheral collar integrally formed on at least one end of said container body;

(b) an upstanding lip integrally formed on said peripheral collar adjacent the inner extremity thereof;

(c) a plurality of discrete tabs integrally formed on said upstanding lip adjacent the upper extremity thereof with the free ends of the tabs inwardly disposed;

(d) a downwardly depending inner flange integrally formed on said closure member and interfitting into said hollow container body so as to resiliently flex said tabs downwardly and outwardly, said inner flange having an outwardly directed shoulder adjacent the lower extremity thereof and disposed below and in locking engagement with the free ends of the resiliently flexed tabs;

(e) a downwardly depending outer flange integrally formed on said closure member and registering with the upper exposed wall of the container body and in overlying relationship to said collar and lip, lower portions of said outer flange engaging upper surfaces of said collar and outer surfaces of said lip;

whereby said tabs and shoulder are exteriorly inaccessible and said closure member is substantially nonremovable from said container body once assembled thereto.

2. The container and closure assembly of claim 1 wherein said lower portions of said outer flange are bifurcated, the outer section of the bifurcated portions engaging upper surfaces of said collar, the inner section of the bifurcated portions engaging at least the outer surfaces of said lip.

3. The container and closure assembly of claim 1 wherein said lower portions of said outer liange engage outer surfaces of said lip adjacent the upper extremity of said lip.

4. The container and closure assembly of claim 1 wherein said tabs are scored adjacent said upstanding lip to form exure-prone lines thereon.

5. The container and closure assembly of claim 1 molded of polyethylene.

References Cited UNITED STATES PATENTS 1,761,603 6/ 1930 Wainwright 220--60 3,189,071 6/1965 Balkema 150-.5 3,251,499 5/1966 Rausing 150-.5 X 3,263,724 8/1966 Mojonnier 150-.5 3,298,415 1/1967 Klygis 150-.5

DONALD F. NORTON, Primary Examiner U.S. Cl. X.R.

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