Snap on closure

Abstract

A plastic pail lid opening surrounded by an upstanding closure receiving cylindrical neck is modified to incorporate a shorter outer cylindrical collar surrounding the neck. A closure assembly made up of an internally threaded closure fitment and a hand applied plug is affixed to the opening neck. The threaded opening is surrounded by an integrally molded sealing channel having an axially extending inner wall and a peripheral interlocking outer wall. To secure the closure assembly to the pail opening the inner wall is guided within the opening neck while the outer wall is axially forced between the outer surface of the upstanding neck and the inner diameter of the surrounding cylindrical collar. With the sealing channel outer wall interlockingly squeezed between the opening neck and surrounding collar, a liquid tight tamper resistant connection is formed.

Description

[0002] This invention is directed to an all plastic dispensing closure for plastic containers.

[0003] In the field of plastic injection molded open head pails a transition is taking place toward all plastic closures. This movement is principally to accommodate environmental recycling concerns and, of course, also to effect attainable cost reductions. The market at this stage has determined that an all plastic dispensing closure can be snapped on to the upstanding opening neck of a pail lid and successfully meet the various performance criteria set by UN and DOT regulations. To date, however, those all plastic dispensing closures successfully commercialized still leave some gaps in the desirability agenda.

[0004] For example, U.S. Pat. No. 5,788,100 dated Aug. 4, 1998 discloses an all plastic snap-on closure made up of a flexible pouring spout surrounded by an annular sealing channel and fitted with an overlying screw cap. A locking ring is integrally connected about the periphery of the screw cap so as to extend radially outwardly of the spout sealing channel. In application the closure is pressed onto a circumferentially enlarged upstanding opening neck causing the sealing channel to snap thereover. During the closure application the locking ring is broken away from the cap periphery and axially pressed around the outer wall of the sealing channel so as to lock the same against the opening neck. The result is a very strong closure container wall connection. The downside resides in the fact that the locking ring can be easily pried off without damage, leaving the closure exposed to undetected tampering and pilferage, which negatively impacts universal acceptance.

[0005] Another example is U.S. Pat. No. 5,797,525 and U.S. Pat. No. 5,641,099 dated Aug. 25, 1998 and Jun. 24, 1997 respectively which also show an all plastic snap-on closure made up of a flexible pouring spout surrounded by an annular sealing channel and fitted with an overlying screw cap. These constructions also embody an outer locking ring integrally connected by frangible webs about the periphery of the screw cap. In application the closure is pressed onto a circumferentially enlarged upstanding opening neck causing both the sealing channel outer wall and the peripheral locking ring to snap thereover. This arrangement causes both the spout outer sealing channel and the peripheral locking ring to expand over the neck enlargement and then relies solely on the elastic memory of the plastic parts to radially contract below the neck enlargement and hold the parts tightly together. The principal problem with this construction is the inability under varied manufacturing conditions to consistently retain a tight seal due to elastic memory alone. In addition undetected tampering can also be readily accomplished by simply prying the fitting off of the opening neck.

SUMMARY OF INVENTION

[0006] The invention closure overcomes these prior art deficiencies in a very simple and straightforward manner. As explained above, the current prior art practice is to one way or another during application, surround the fully seated sealing channel outer wall with a locking ring introduced as an integral part of the closure. In accordance with the invention the locking ring is instead integrally molded in the pail lid as a raised annular collar spaced from and surrounding the upstanding opening neck. The outer wall of the spout sealing channel is then squeezed during application into the annular gap formed between the neck and the collar creating a very strong, liquid tight and torque resistant engagement between the closure and the pail lid. In the resulting construction the sealing channel is completely self supported in that no other closure part is employed to aid securement. The advantages of the invention closure are immediately apparent. There is no breaking away of relatively fragile parts which are then stretched around other parts. There is no reliance on elastic memory for holding parts together. Most importantly, the tamper resistance of the invention closure is substantially increased, as there is no readily undetectable way the fitting or any part thereof can be pried off the pail lid. This characteristic in itself clearly distinguishes the invention closure over other snap-on all plastic closures currently in use. Moreover the ultimate simplicity of application to the pail lid easily constitutes a further advance in the art. In addition the dispensing closure here consists of an internally threaded closure fitment and a mating self gasketed closure plug, together forming a unique sealing arrangement.

[0007] It is accordingly a principal object of the invention to provide a new and improved all plastic snap on container closure embodying a self supported sealing channel.

[0008] Another object is to provide an all plastic, torque resisting dispensing closure incorporating a hand tightened screw plug.

[0009] A further object is to provide a new self gasketed closure plug for use in conjunction with an all plastic snap on closure fitment.

[0010] Other and more detailed objects of the invention will in part be obvious and in part pointed out as the description taken in conjunction with the accompanying drawing proceeds.

[0011] In that drawing:

[0012] FIG. 1 is a vertical sectional view of a closure assembly prior to application to a container neck in accordance with the invention;

[0013] FIG. 2 is a vertical sectional view of a container neck of the invention for receiving a closure assembly;

[0014] FIG. 3 is a top plan view of the invention closure fitment;

[0015] FIG. 4 is a partial vertical sectional view showing the closure assembly positioned on the opening neck.

[0016] FIG. 5 is an enlarged fragmentary view showing initial engagement of the plug and fitment:

[0017] FIG. 6 is a view similar to FIG. 5 with the plug fully seated;

[0018] FIG. 7 is a view similar to FIG. 4 of an alternate closure construction;

[0019] FIG. 8 is an enlarged fragmentary view of the alternate closure similar to FIG. 5, and

[0020] FIG. 9 is another view similar to FIG. 8 showing the closure plug in fully seated position.

DETAILED DESCRIPTION OF THE INVENTION

[0021] The container closure assembly generally indicated at numeral 1 in FIG. 1 is seen to consist of a closure fitment 2 molded of low density polyethylene and an overlying closure plug 3 molded of high density polyethylene or similar higher density plastic resin. The fitment 2 is formed with an axially extending cylindrical body 4 closed off by a tear out membrane 5 having a ring pull 6. The upper portion of the body 4 above the membrane 5 has an internal thread 7 and is joined at its uppermost end to circumferential sealing channel 9. The sealing channel 9, as clearly seen in FIG. 4, has an axially elongated inner cylindrical surface 10 which extends downwardly and to an inwardly extending conical surface 11 further provided with vertical drainage slots 12. The top surface of sealing channel 9 has an annular sealing groove 13 with a V shape in vertical cross section. The sealing channel 9 is further provided with an outer wall 14 having an exterior upward and radially outwardly facing camming surface 15 at its upper end. Conical surface 15 joins a cylindrical outer surface 16 which terminates in an annular upwardly facing load bearing surface or shelf 17 on circumferential presser foot 18. The bottom of presser foot 18 has a downwardly and radially outwardly facing conical surface 19. The inner surface of outer sealing channel wall 14 has an internal bead 20 partially closing off the mouth of the sealing channel and terminating at its lowermost end in radially inwardly and downwardly facing conical surface 21.

[0022] The closure plug 3 has a disc like top wall 22 with a cylindrical skirt 23 depending therefrom having an external thread 24 for engagement with the internal thread 7. The plug as thus described and seen in FIG. 4 has a circumferentially enlarged peripheral flange 25 and outer edge formed with a series of vertical ribs 26 to enhance gripping. The undersurface of the flange 25 has an annular protruding sealing rib 27 formed with inner and outer corners 28 as viewed in vertical cross section. As seen in FIG. 5 when the plug 3 is merely snugged into the fitment 2 such as when the tear out membrane 5 is in tact, the rib corners 28 just contact the sides of the sealing groove 13 leaving a slight gap 29 between the undersurface of the flange 25 and the top surface of the sealing channel 9. After removal of the tear out membrane sealing of the plug within the fitment obviously becomes more important. At this time as clearly seen in FIG. 6, the plug, by gripping the outer ribbed edge, is tightened in the fitment so that the corners 28 of the relatively higher density rib 27 bite into the sides of the groove 13 which is a softer, lower density material. The resulting deformation as indicated by the numeral 28a, seals against any leakage path between the mating parts. It will also be noted at this point the gap 29 is completely closed off resulting in a highly efficient sealing engagement between the plug and the fitment.

[0023] As seen in FIG. 2 a container wall or in this case a pail lid 30 is shown having an upstanding neck 31 surrounding the standard dispensing opening and terminating in a circumferentialy enlarged retaining lip 32. A locking collar 33 is concentrically disposed radially outwardly spaced from neck 31 creating an open annular groove 34.

[0024] In operation the closure 1 is placed on the opening neck 32 with the inner sealing channel surface 10 entering the lid opening and with the conical wall surface 11 acting as a guide. In this position the sealing channel outer wall camming surface 21 rests on the opening neck lip 32. An axially driven insertion tool is placed over the closure with the camming surface 15 acting as a guide the tool acts against the presser foot bearing surface 17 and against the cap top wall 22. Continued vertical displacement of the camming surface 21 on bead 20 brings presser foot camming surface 19 into engagement with the inner top corner of the locking collar 33. The final small amount of vertical displacement bumps the presser foot inside the collar 30 so that the bottom surface of the outer channel wall 14 rests against the bottom of groove 34. In this position it can be seen that the internal bead 20 has moved past the neck lip 32 and become locked securely thereunder.

[0025] From the forgoing the numerous advantages of the invention are readily apparent. First and foremost, the invention closure is substantially more tamper resistant than other all plastic closure constructions. Vertical retraction of the pressure foot 18 from the groove 34 is prevented by the interlocking undercuts between the opening neck and the outer channel wall. Prying the presser foot out of the groove 34 is a virtual impossibility without clear indication of tampering. The high radial compression created between the collar 30 and the inner channel wall 10 assures a liquid seal under the most rigorous conditions. In addition the radial contraction of the spout inner wall serves to effectively tighten the engagement with the cap skirt 28 so that inadvertent dislodgment of the locking of the locking rib 29 with the groove 13 becomes unlikely due to unavoidable upward force or pressure on the bottom of the nested spout. A further advantage in the invention construction is the ability to also apply, if need be, a conventional crimped on closure to the opening neck configuration. This flexibility has significant commercial ramifications.

[0026] As indicated by the force diagram arrows A-A in FIG. 4, it can be seen that a mechanical couple is acting against the bead 20 and the heal of the presser 18. This arrangement of parallel and opposite forces enables the sealing channel to grip the container opening neck in a very effective self supported manner without the aid of any additional supporting structure such as an overlying band, cap skirt or the like.

[0027] An alternative embodiment is shown in FIGS. 7-9 wherein closure fitment 40 similar is in all material respects similar to the closure fitment 2 of the principal embodiment with the exception of the two annular sealing beads 41 and 42 extending from the top surface of sealing channel 43. A closure plug 44 is screwed into the closure fitment 40 as in the principal embodiment and is formed with a step 45 formed on the undersurface of the plug peripheral flange 46 creating a plug sealing surface 46. The closure assembly is snapped on the pail lid 47 as in the principal embodiment resulting in a liquid tight, tamper resistant connection. As seen in FIG. 9 when the plug 44 is tightened into the fitment 40 for effective sealing the step 45 is drawn down onto the sealing channel 43 with consequent deformation of the sealing ribs as indicated at 41a and 42a. This arrangement as the principal embodiment effectively seals off any possible leakage path between the plug and fitment.

[0028] Various other changes in or modifications to the closure and insertion method of the invention would suggest themselves to those skilled in the art and could be made without departing from the spirited and scope of the invention. For example, different types of relatively higher and lower density plastic resins could be employed to mold the plug and fitment. It is accordingly intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as being illustrative and not in a limiting sense.

Claims

1. In combination, a container wall having a closure receiving opening therein, said opening surrounded by a closure receiving structure, a threaded dispensing closure assembly interlockingly engaging said closure receiving structure, said interlocking engagement exerting a mechanical couple force between said closure and said structure whereby a substantial degree of torque resistance is created between said closure and said container wall.

2. A combination as in claim 1 and said closure receiving structure including an axially extending neck.

3. A combination as in claim 2 and said closure receiving structure including rigid means disposed externally of said neck.

4. Dispensing closure fitment molded of synthetic plastic resin having a centrally disposed pour opening, an annular sealing channel surrounding said pour opening, said sealing channel configured to effect a self supported sealing engagement with a container wall opening, a cylindrical closure member engaging said pour opening, said closure member including a circumferentially enlarged flange extending radially outwardly so as to overlie said sealing channel and annular axially extending sealing means interposed said flange and said sealing channel whereby a compressive force therebetween causes a deformation of said sealing means.

5. An all plastic closure as in claim 4 wherein said deformation limits axial displacement of said flange relative to said sealing channel.

6. An all plastic closure as in claim 4 said flange and said sealing channel presenting interacting opposing annular sealing surfaces.

7. An all plastic closure as in claim 4 wherein said cylindrical closure member is molded from a higher density plastic resin than said closure fitment.

8. An all plastic dispensing closure fitment having a centrally disposed pour opening, an annular sealing channel surrounding said pour opening, said sealing channel configured to effect a self supported torque resistant sealing engagement with a container wall opening, a threaded closure member engaging said pour opening, said closure member including a torque applying surface disposed radially outwardly of said sealing channel whereby a sealing torque is readily applied to said closure member and resisted by said sealing channel.

9. An all plastic dispensing closure as in claim 7 wherein said torque resisting surface is a circumferentially enlarged flange overlying said sealing channel.

10. An all plastic dispensing closure as in claim 8 and axially extending ribs disposed about the periphery of said flange.