US3814274A

US3814274A - Linerless closure for a container

Info

Publication number: US3814274A
Application number: US00241155A
Authority: US
Inventors: Intosh J Mc
Original assignee: Mack Wayne Plastics Co
Current assignee: Mack Wayne Plastics Co
Priority date: 1972-04-05
Filing date: 1972-04-05
Publication date: 1974-06-04
Anticipated expiration: 1991-06-04
Also published as: ES226932Y; ES226932U

Abstract

A linerless closure for a container has a top wall with a cylindrical skirt adapted to engage the neck of a container. An annular bead is provided inside the top wall of the closure and aligned with the wall of the neck of the container, and a ''''prebent'''' annular sleeve extends downwardly from the top wall of the closure, radially inwardly of the bead, the sleeve extending downwardly and outwardly in a first arcuate portion and thence downwardly and outwardly in a tapered portion that extends into axial alignment with the bead.

Description

United States Patent 1191 McIntosh June 4, 1974 I LINERLESS CLOSURE FOR A CONTAINER [75] Inventor: James A. McIntosh, Upper Montclair, NJ.

[73] Assignee: Mack-Wayne Plastics Company,

Wayne, NJ.

[22] Filed: Apr. 5, 1972 21 Appl. No.: 241,155

[52] US. Cl. 215/344, 215/D1G. 1 [51] Int. Cl B65d 41/04 [58] Field of Search 215/D1G. 1, 4O

[56] References Cited UNITED STATES PATENTS 9/1962 Plunkett .1 215/43 R x Mclntosh....

3,344,942 10/1967 Hedgewick 215/40 X Primary ExaminerDonald F. Norton Attorney. Agent, ,or FirmAlbert C. Nolte, Jr.; Edward B. Hunter; Charles B. Hamburg [5 71 ABSTRACT A linerless closure for a container has a top wall with a cylindrical skirt adapted to engage the neck of a container. An annular bead is provided inside the top wall of the closure and aligned with the wall of the neck of the container, and a "preben't annular sleeve extends downwardly-from the top wall of the closure, radially inwardly of. the bead, the sleeve extending downwardly and outwardly in a first arcuate portion and thence downwardly and outwardly in a tapered portion that extends into axial alignment with the bead.

3 Claims, 5 Drawing Figures LINERLESS CLOSURE FOR A CONTAINER This invention relates to sealing closures for use on containers, such as containers which may have neck portions having threads or other configurations adapted to cooperate with suitable configurations on the closures. The invention is particularly directed to such closures of the linerless type, i.e., that do not require a separate lining means to effect the seal on the container.

In the past, linerless sealing closures have been provided for sealing the threaded necks of various containers. Such closures are generally molded from a resilient plastic material, such as polypropylene. The closures generally have a top wall from which a cylindrical skirt extends, the skirt having internal threads adapted to be fitted over the threads of the neck of the container. Resilient annular beads are integrally molded with the cap on the inner surface thereof, to provide a tight seal with the end of the neck of the container when the closure is tightened thereon. Containers frequently have uneven upper rim surfaces, however, as a consequence many such linerless sealing closures do not have sufficient flexibility to seal the containers tightly and withstand repeatedsealing and unsealing operations without deformation.

In order to overcome this problem, as disclosed in my US. Pat. No. 3,286,866, which issued on Nov. 22, 1966, an improved closure to overcome the above problem is provided with an annular reslient bead on the underside of the top wall and concentric with the threaded skirt. The annular resilient bead has a median diameter greater than the diameter of the inner wall of the neck of the container, but less than the diameter of the outer wall of the neck. In addition, the closure member of the above patent provides an annular resilient sleeve positioned on the underside of the top wall within the annular resilient bead, the sleeve being joined to the top wall at its inner peripheral edge, and extending therefrom angularly downwardly from the top wall and outwardly toward the cylindrical skirt. The sleeve thus is in the form of a hollow truncated cone tapering outwardly from its point of attachment to the top wall. The slant height of the sleeve from its inner peripheral edge to its outer peripheral edge is greater than the radial distance between the inner peripheral edge thereof and the bead. In the arrangement of the above patent, when the closure member engages the threaded neck of the container and is advanced downwardly to its sealed position, the resilient sleeve is deflected upwardly and outwardly, so that it bears against the resilient annular bead. The sleeve then is supported at its inner peripheral edge by its attachment to the top wall, and is supported at a second point, generally close to its outer peripheral edge, by the resilient annular bead, the rim of the neck of the container being maintained in contact with the resilient sleeve generally intermediate these points, in order to create an effective sealing relationship. Whilethe linerless seal as above described is satisfactory in many applications, it has been found that certain problems arise when a seal of this type is employed on a container having a large neck diameter. As the diameter of the container neck is increased, the circumferential dimension of the seal is of course also increased in the cap, and, without changing other parameters of the seal, it is apparent that the force required to deform the sleeve also increases. Thus, when the diameter of the neck is greater than about 2 inches, it has been found that the torque necessary on the closure to obtain an effective seal becomes greater than desired, with the consequence that it is difficult for an average individual to rotate the closure to obtain an effective seal, and it is also more difficult to remove the closure from the neck of the container. In addition, in view of the torque required for sealing such larger caps, the individual does not exercise the same degree of control in tightening the closure on the neck of the container, so that the individual may exert excessive torque on the cap to effect the seal, and in the process exceed theelastic limit of the sleeve, thereby losing the desired seal as well as the back-off torque. In this type of seal, since the sealing sleeve is in effect supported at each end by the top wall of the closure, and engages the neck of the container at a point generally intermediate its ends, it is important that the sleeve be free to flex up and down intermediate its ends to hold the seal, and thus bending of the sealing sleeve beyond its elastic limit effects a permanent deformation of this member with the consequent loss of resilience of the member in holding the seal tight. While the torque necessary to effect a seal may of course be reduced by merely reducing the thickness of the sealing sleeve, this expedient does not provide a solution to the problem, since the sealing sleeve then does not have sufficient resilience to maintain a tight seal.

' It is therefore an object of this invention to'provide a linerless seal which overcomes the above problems of the prior devices, and which provides an effective seal between the closure and the neck of larger diameter containers without requiring excessive torque to effect the opening and closing of the container.

Briefly stated, in accordance with the invention, it has been found that the above'object can be attained by initially forming the sealing sleeve to have a shape that more nearly conforms to its final sealing position, i.e., in effect to a prebent" configuration, so that less torque is required to deform the sealing sleeve to its sealing position when on the neck of the container. The amount of necessary deformation of the sealing sleeve to form the effective seal is thereby reduced, and no sacrifice is necessary with respect to the resilience of the sealing sleeve itself. In addition, since the amount of torque required to effect the seal is reduced, there is less danger that an individual will apply excessive torque to the closure to exceed the elastic limit of the material of the sealing sleeve.

While the invention has been explained in terms of the problem which arose when linerless closures were provided for containers having necks of relatively large diameters, it should be clear that the invention, is equally advantageous in providing less torque for both opening and closing the smaller closures of the linerless type.

The invention will now be disclosed in greater detail with reference to the accompanying drawings, in which:

FIG. 1 is a top view of a linerless closure according to the invention;

FIG. 2 is an enlarged cross sectional view of the cap of FIG. 1 taken along the lines 2-2, and illustrating the closure in position on the neck of a container but not sealed thereto;

FIG. 3 is an enlarged cross sectional view of a portion of the closure of FIG. 2 in the same position;

FIG. 4 is an enlarged view of the closure of FIG. 2 illustrated in sealed position with the sealing sleeve engaging the top of the neck of the container; and

FIG. 5 is a cross sectional view of the closure of FIG. 2 taken along the lines 5-5.

Referring now to the drawings, and more in particular to FIGS. 1 and 2, therein is illustrated a closure according to one embodiment of the invention comprised ofa top wall 10, which may be in the form ofa circular disk, and having a cylindrical skirt 11 extending from the bottom edge thereof; The cylindrical skirt 11 has internal threads 12 or other equivalent configurations formed therein for engaging the threads or equivalent configurations on the end of the neck 13 of a container wardly from the bottom of the top wall 10. The sleeve 21 is affixed to the top wall radially inwardly of the bead 20, and the bead and sleeve 21 are concentric and coaxial with respect to the axis of the skirt 11 and hence the neck of the container 14.

The annular head 20 and annular sleeve 21 are more clearly illustrated in the enlarged view of FIG. 3. Referring now to FIG. 3, the annular bead 20 is positioned so that it projects downwardly in line with the neck wall 13 of the container, the mean radius of the bead from the axis of the container being approximately equal to the mean radius of the neck wall of the container. The width of the bead is substantially less than the width of the neck of the container. The bottom 25 of the bead 20 is preferably generally flattened, and the sides thereof extending to the top wall of the closure are preferably tapered, with the outer wall 26 being formed at a slightly greater angle than the inner wall 27 with respect to the surface of the top wall. For example, in one embodiment of the invention, the angle between the wall 26 and the top wall 10 was about 92, the angle between the inner wall 27 and the top wall 10 was about 105, the width of the end surface 25 was about 0.01 inches, and the distance between the bottom 25,0f the bead and the wall 10 was about 0.008 inches. With such dimensions, the bead 20 may be deformed slightly outwardly when the closure is in sealed position, with the bead 20 still retaining sufficient strength to form an end support for the end of the sleeve 21.

The annular sleeve 21 extends from the bottom of the top wall 10 radially inwardly of the bead 20, at a position preferably inwardly of the inner wall of the neck 13 of the container. The sleeve 21 is generally tapered as it extends downwardly, the lower portions being bent outwardly so that the end 30 thereof is in line with the mean radius of the bead 20 from the axis of the closure. Thus, the inner wall 31 of the bead is formed normal to the top wall 10 at its juncture therewith, and having a generally straight end portion 32 terminating in the end 30, and a circular transition portion 33 between the end portion 32 of the wall and the top wall 10. The outer wall 35 of the sleeve is similarly formed, having an end portion 36 that is generally straight and joins the end 30, and a circular transition region 37 between the straight portion 36 and the junction of the sleeve 21 with the top wall 10. The centers of curvature of the 4 portions 33-and 35 of the sleeve 21 are approximately at the surface of the wall 10, and are outwardly of the respective portions of the sleeve 21. The sleeve 21 thus has the form of a prebent member extending downwardly and outwardly from the bottom of the top wall 10.

In one embodiment of the invention, having a bead with the dimensions as aforestated, the thickness of the base of the sleeve 21 was about 0.028 inches, the curved portion 33 had a radius of curvature of about 0.032 inches, the radius of curvature of the curved portion 35 was about 0.02 inches, the straight portion 32 had an angle of about 15 with respect to the bottom surface of the top wall 10, the straight portion 36 forms an angle'of about 25 with respect to the bottom surface of the top wall 10, the radial distance between the bead 20 and sleeve 21 was about 0.026 inches, and the width of the bottom 30 of the projection 21, in the direction parallel to the axis of the closure, was about 0.012 inches. The overall extension of the projection 21 from the bottom of the top wall 10 was about 0.04 inches as molded.

Referring now to FIG. 4, therein is illustrated the relationship between the closure according to the invention and the container when the closure has been drawn into sealing relationship, for example, by relative rotation of the closure with respect to the threads on the neck of the container. It is apparent that the end of the neck of the container has contacted the end of the portion 32 of the sleeve2l, and the sleeve 21 has been forced toward the top wall 10 so that the portion 36 of the outer wall of the sleeve 21 engages the end 25 of thebead 20. The bead 20 and the sleeve 21 arepositioned so that the greaterportion of the force exerted on the sleeve 21 lies between the axis of the bead 20 and the base of the sleeve 21. As a consequence, the deformation of the sleeve 21 is primarily in this region, with a minimum of stress being applied to the sleeve 21 at the region where it joins'the top wall 10. Furthermore, since the sleeve 21 was formed with a prebent configuration, the amount of torque necessary of the closure to deform the sleeve 21 to the position indicated in FIG. 4 is minimized, with the result that the closure is easier to seal, the deformation of the sleeve is minimized, and the danger of insufficient torque to effect a seal or excess torque to permanently deform the sleeve'2l are minimized.

FIG. 5 is a cross sectional view of the closure in the position illustrated in FIG. 2, taken along the lines 55, in order to more clearly illustrate the structure therein illustrated.

As in the closure of the above mentioned US. Pat. No. 3,286,866, the closure of this invention may be fabricated from a variety of materials and in several different manners. Thus, the top wall and cylindrical skirt can be made of any material possessing the required strength and rigidity, such as any of the more common metals or the more rigid plastics. The bead and sleeve are preferably formed from any other well known resilient plastic materials. The material employed for the resilient sleeve, however, must not be so flexible that the rotation of the closure when brought into contact with the resilient sleeve in sealing relationship will cause the sleeve to become twisted. The top wall including the skirt of the closure can be fabricated as a unit, such as by casting or machining, and the prefabricated resilient annular bead and sleeve sealed in place within the skirt. Preferably, however, the entire closure, including the top wall, skirt, annular resilient bead and resilient sleeve, is molded as a unit from a semiflexible, semi-rigid plastic material such as polypropylene.

' While the invention has been disclosed with reference to a single example, it will be obvious that many modifications and variations may be made therein without departing from the spirit and scope of the invention, and is therefore intended in the following claims to cover all such modifications and variations as fall within the true spirit and scope of the invention.

What is claimed is:

1. in a closure for use on the neck of a container of the type wherein the closure includes a top wall and a cylindrical skirt extending therefrom for engagement with the outer wall of the neck of the container, and wherein the top wall of the closure further includes an annular resilient bead extending toward the end of the neck of the container, and an annular sleeve inwardly of the annular bead and extending into alignment with the bead so that the sleeve can engage the end of the neck of the container to form a seal and bend upwardly to engage the annular bead, the improvement wherein said annular sleeve is formed pre-bent, providing a first relatively thick portion of arcuate cross section joined to the top wall and extending therefrom with generally arcuate side walls extending downwardly and outwardly from the surface of the top wall and a tapered thinner end portion joined to the arcuate cross section portion and extending into axial alignment with said resilient bead, whereby during sealing between the sleeve and the end of the neck of the container when the neck of the container engages the thinner end portion of the sleeve and the end portion of the sleeve is urged against the annular bead and during unsealing of the same, said pre-bent sleeve constitutes means for decreasing the torque required to seal and unseal the container.

2. In a linerless closure for sealing a container, wherein the container includes a neck portion adapted to receive the closure, and wherein the closure has a top wall and a cylindrical skirt extending therefrom for engagement with the outer wall of the neck of the container, and wherein an annular resilient bead extends from the inner surface of the top wall in alignment with the neck of the container, and an annular sleeve extends from the surface of the top wall radially inwardly of the annular bead, the annular sleeve extending downwardly and outwardly to engage the end of the neck of the container to form a seal and being bendable to engage the bottom of the annular bead and wherein the annular sleeve is supported from the top wall at a relatively thick base, its free thinner en d extending t oward its point of contact with the annular bead; the improvement wherein said annular sleeve has a prebent shape when not engaging the end of the neck of I the container that has said thin end adjacent the top wall that extends away from the wall at a greater angle than said thick base to thereby constitute the same as means for decreasing the force required to bend said annular sleeve into and out of contact with said annular bead and into and out of sealing engagement with the neck of the container by forces toward and away from said wall upon engagement of said sleeve with the end of the neck of said container.

3. The linerless closure of claim 2 for use on a container having threads on the outer surface of said neck, wherein said cylindrical skirt has internal threads formed therein for engaging the threads on the neck of said container.

Claims

2. In a linerless closure for sealing a container, wherein the container includes a neck portion adapted to receive the closure, and wherein the closure has a top wall and a cylindrical skirt extending therefrom for engagement with the outer wall of the neck of the container, and wherein an annular resilient bead extends from the inner surface of the top wall in alignment with the neck of the container, and an annular sleeve extends from the surface of the top wall radially inwardly of the annular bead, the annular sleeve extending downwardly and outwardly to engage the end of the neck of the container to form a seal and being bendable to engage the bottom of the annular bead and wherein the annular sleeve is supported from the top wall at a relatively thick base and at its free thinner end extending toward its point of contact with the annular bead; the improvement wherein said annular sleeve has a pre-bent shape when not engaging the end of the neck of the container that has said thin end adjacent the top wall that extends away from the wall at a greater angle than said thick base to thereby constitute the same as means for decreasing the force required to bend said annular sleeve into and out of contact with said annular bead and into and out of sealing engagement with the neck of the container by forces toward and away from said wall upon engagement of said sleeve with the end of the neck of said container.