US 3374601 A
Description (OCR text may contain errors)
March 26, 1968 w rr 3,374,601
ROTATABLE CLOSURE Filed Sept. 1, 1965 IO M I5 25 25' 2e 25 l2 2 24 INVENTOR ROBERT P WHITE BY 7 1 57 A 2 a 49 ATT'YS United States Patent ()fiice 3,374,601 Patented Mar. 26, 1968 3,374,601 ROTATABLE CLOSURE Robert P. White, Winnetka, 11]., assignor to Continental Can Company, Inc., New York, N.Y., a corporation of New York Filed Sept. 1, I965, Ser. No. 484,335)
3 Claims. (Cl. 5342) This invention relates to a novel method of applying a closure cap to a container by a combination of a press on and rotational motion. More specifically, the present invention relates to a novel closure cap having a deformable lining which co-operates with threads on the container finish to cause formation of threads in the closure cap during application.
The present invention includes a closure shell which is lined with a deformable plastomeric material around the inner perimetrical surface. The lining serves a dual function inasmuch as it seals the cap to the container while forming threads for co-operation with threads on the finish of the container to permit removal by rotation. The closure cap is applied in a manner to assist in formation of threads since itis applied with a vertical and rotational motion causing the threads on the container finish to deform the liningmaterial into co-operating threads permitting removal. The lining compound may be flexible and cold flowable so that after'capping, the compound fills any voids on the finish or adjacent the threads, ultimately becomes substantially firm relative to its consistency at application, to permit removal and reapplication of the closure cap.
The specific details and broad advantages of the present invention will be better comprehended upon a consideration of the objects achieved and a detailed description of the salient features of the invention.
It is an object of the invention 'to provide a new and improved closure assembly.
A further object of this invention is to provide a closure cap which is lined with a suitable compound and applied with a rotational motion to a threaded container whereby threads will be easily formed in the lining.
It is a still further object of this invention to provide a new and improved closure arrangement wherein threads are formed in the gasket compound by rotating the shell on application to substantially fill'the space between the container finish and the closure shell thereby to preclude foreign matter from collecting between the shell and finish.
Additional objects other than those specifically enumerated will become apparent in the course of the following description of a preferred embodiment while other modifications will become clearly apparent to those who read the description and study the drawings.
FIG. 1 is a side elevational view of a fragmentary portion of the upper part of a container having a closure cap of the present invention illustrated in cross section poised for application to the container;
FIG. 2 is a view similar to FIG. 1 with the cap at an intermediate stage of application with the container illustrated in cross section;
FIG. 3 is a view similar to FIG. 1, with the cap illustrated in cross section in the final position after completion of application; and
FIG. 4 is a view in elevation of a fragmentary portion of the compound lining the cap after removal from the container.
The closure cap shown in the drawings consists of the usual shell having a top panel 11 and skirt 12 which may be curled at its lower margin as at 13. A gasket groove 14 may be formed in the top panel by depressing a portion thereof as at 15 to form what is known in the art as a stacking panel. The shell 10' is lined with an 'elastomeric or plastomeric compound 16 which extends along the inner circumferential surface 17 of the skirt and fills the gasket groove 14. For example, the gasket may be formed from compounds such as those described in the patent to Ungeret al., No. 2,874,863 and Zipper, No. 2,841,304, and have the properties given below. In the present shell and those in which the top panel 11 is flat, the gasket may terminate along a circle of any desired diameter, or extend completely across and cover the entire underside of the panel 11.
A container 18 having a main body 19' (shown fragmentarily) is joined through a necked in portion 21 to a sealing finish portion indicated generally at 20. The container finish portion 20 may be of any suitable shape and in the present design is of generally frusto-conical contour having a solid circumferential portion 22 which joins a reduced portion 23 through a shoulder 24. On the portion 23 of reduced diameter is provided a plurality of threads 25 which are embossed on the portion of reduced diameter each of which the the flat crest 26 lying in a circumferential surface which constitutes an imaginary projection of the frusto-conical surface 22. Each of the illustrated threads 25 is of trapezoidal cross sectional configuration as is evident in the cross sectional view of FIG. 2, however, may be of any desired cross sectional shape which is suited for the application of the closure shell and subsequent formation of threads in the gasket lining compound 16 in a manner to be described.
In FIG. 2, the cap 10 is illustrated in an intermediate stage of application to the container 18. The cap is applied with known type of equipment which presses the cap downwardly in a vertical direction on the container finish 20 while simultaneously rotating the same. At an intermediate stage of application such as shown in FIG. 2, the threads 25 intercept the deformable compound 16 and enter the same to form co-operating threads. As cap application is continued, the compound 16 is further deformed until the shell 10 assumes the final position shown in FIG. 3. At this time, threads 25 have entered and deformed the compound 16 to complete the formation of co-operating threads. By rotating the cap during application, less gasket material or compound will have to .be forced over the crest of the threads making the application easier.
At initial application, the compound may be quite soft permitting the thread forming step to be performed with little difficulty. When compounds such as plastisols are used, processing at an elevated temperature or the passage -of time at room temperature causes flow of the material to surround the threads, enter any voids in the container finish and substantially occupy the entire space between the container finish 20 :and the inner circumferential portion 17 of the shell 10 to form a hermetic seal. The seal is continuous along the side of the finish as well as at the top, since the upper rim of the container finish portion 20 engages the inwardly projecting gasket compound.
The entry of the finish into the shell is such that the compound 16 is deformed an amount which can be predeter-mined by controlling the volume of gasket material applied. Such deformation may be sufficient to cause the compound 16 to overlie the raw edge of the curled portion 13. In this manner, a seal of substantial length is provided along the side and top of the container finish. Since rigidity of the shell is not as important to the seal, the shell may be made of lighter weight material.
After further processing at an elevated temperature or the passage of time, the compound 16 becomes sufliciently firm to permit removal of the cap. FIG. 4 shows a fragmentary portion of the skirt 12 in elevation after the removal from the container and illustrates the shape of the co-operating threads 26 formed in the compound 16 by application of the lined shell to the container finish. A circumferential-frusto-conical portion '27 --is formed between the curl 13 and the de-bossed thread portion 26. This prevents the collecting of dust, dirt, mold, insect larva or the like between the skirt 12 and the container in addition to providing an additional seal of long length to preclude the possibility of oxygen permeation when the product has anunusually long period of storage.
The type of gasket material may vary'with the particular application, however, certain characteristics or properties are required if application, removal, and re-application of the cap, are to be easily effected. During cap 7 application, the gasket material must be of sufiiciently low modulus to enable forming around the threads or projections on thecontainer finish. The surface of the selected material must be suffic'iently durable and tough to preclude tearing during application and have a good adherence to the shell. Also, the gasket material must exhibit rigid or semi-rigid properties after application to permit removal and re-application using the previously for-med threads. For example, this may be achieved by curing the selected material by heating or merely the passage of time. Yet, it must exhibit suflicient immediate resilience to form a seal which will be maintained over wide temperature changes and the usual impacts until the container is opened. That class of materials or compounds known as plastisols has been used with good results, but any material having the above properties is equally satisfactory forthe stated purposes.
While the foregoing embodiment has been described in connection with a frusto-conical shell and cap, it will become obvious that a cylindrical shell and appropriate container finishare equally acceptable. Other modifications may be made without departing from the inventive concepts embodied herein and therefore only such limitations should be imposed as are indicated by the spirit and scope of the appended claims.
' 1. The method of capping a container to form threads permitting removal and re-application of said caps, said method comprising the steps of lining a closure shell with a gasket material having sufficient adhesion to preclude tearing away from the shell during cap application and removal, applying said cap over a threaded portion of a container finish with a press-on type motion while simultaneously rotating said shell to shape said gasket material to conform to the threaded portion of said container finish, said gasket material having suflicient toughness at the surface thereof during application to preclude hardness whereby it has suflicient rigidity to -perinitretearing, and curing said shaped gasket material to a movalof saidcap by rotating the same relative to said container while being sufficiently resilient to form 9. hermetic seal. 7
2 The method of applying a closure cap to a container, having a threaded finish while simultaneously forming threads'in said closure cap 'to permit rotational removal, said method comprising lining said closure cap with a gasket material having a low modulus to enable forming around threads on said" container while'being sufiiciently tough on the surface thereof to preclude tearing during application, pressing said closure cap lined with said material onto said threaded finish with a generally vertical downward and rotational motion to cause said threaded finish to cut co-operat-ing thread recesses in said material while said material simultaneously forms a hermetic seal between said closure cap and said container finish, curing said material whereby said threaded formations become sufliciently rigid to permit removal and re-application of said closure to said container.
3. The method of capping a containerto form threads permitting removal and re-application of said caps, said method comprising the steps of lining aclosure shell with a gasket material having-suflicient'adhesion to preclude tearing away from the shell during cap application and removal, applying said cap overa threaded portion of a container finish with a presson type motion while simultaneously rotationg said shell to initiate shaping of said gasket material, said gasket material being sufiiciently flowable to permit conforming thereof to the threaded portion of said container finish, said gasket material having suflicient toughness at the surface thereof during application to preclude tearing, and curing said shaped gasket material to a hardness whereby it has sufficient rigidity to permit removal of said-cap .by rotating the same relative to said container while being sufliciently resilient to form a hermetic seal;
References Cited UNITED STATES PATENTS WILLIAM W. DYER, Jr., Primary Examiner. R. L. FARRIS, Assistant Examiner.
9/1938 Greenhol-tz et a1. 21s 43.1