US3888376A

US3888376A - Safety closure cap for containers

Info

Publication number: US3888376A
Application number: US479044A
Authority: US
Inventors: Carl W Cooke
Original assignee: CWC IND
Current assignee: INVENTIVE PACKAGING Corp A CORP OF CO; CWC IND
Priority date: 1974-06-13
Filing date: 1974-06-13
Publication date: 1975-06-10
Anticipated expiration: 1992-06-10

Abstract

A safety closure cap for sealing the open end of a container is disclosed consisting of a top portion, a threaded cylindrical skirt portion adapted to be received about the threaded neck portion of the container and a resilient sealing member carried on the inner face of the closure top. The thread portion of the closure includes an enlarged start end portion which defines an upstanding shoulder located on the thread upper face at the juncture of the enlarged start end portion and the remaining portion of the thread. The upstanding shoulder engages with a cooperating shoulder formed on the lower face of the neck thread (responsive to the urging of the resilient sealing member) when the closure is axially drawn into sealing relation with the open end of the container to lock the threads of the closure and the container neck and prevent removal of the closure by simply rotating the closure in the opposite direction. The closure is removed by a downward force to compress the sealing member and allow the cooperating shoulders to disengage whereupon the threads are unlocked and the closure removed by rotation in a reverse direction.

Description

United States Patent 1 Cooke [21] Appl. No.: 479,044

US. Cl 215/217; 2l5/2l6 Int. Cl. 365d 55/02; B65d 85/56; A61} l/OO Field of Search ..2l5/2l6,2l7.9.2l8

[56] References Cited UNITED STATES PATENTS l/l957 Thornton ..2l5/2l7 6/1973 Wittwer ..2l5/2l7 Primary Examiner-George T. Hall Attorney. Agent. or Firm-Fulwider, Patton, Rieber. Lee & Utecht [57] ABSTRACT A safety closure cap for sealing the open end of a con June 10, 1975 tainer is disclosed consisting of a top portion, a threaded cylindrical skirt portion adapted to be received about the threaded neck portion of the con; tainer and a resilient sealing member carried on the inner face of the closure top. The thread portion of the closure includes an enlarged start end portion which defines an upstanding shoulder located on the thread upper face at the juncture of the enlarged start end portion and the remaining portion of the thread. The upstanding shoulder engages with a cooperating shoulder formed on the lower face of the neck thread (responsive to the urging of the resilient sealing member) when the closure is axially drawn into sealing relation with the open end of the container to lock the threads of the closure and the container neck and prevent removal of the closure by simply rotating the closure in the opposite direction. The closure is removed by a downward force to compress the sealing member and allow the cooperating shoulders to disengage whereupon the threads are unlocked and the closure removed by rotation in a reverse direction.

8 Claims, 4 Drawing Figures I s. was! 33:

1 SAFETY CLOSURE CAP FOR CONTAINERS BACKGROUND OF THE INVENTION This invention relates to closures for containers and more particularly to the so-called *safety closures which, once drawn into sealing engagement with the closure, can be removed only by a special manipulative procedure beyond the capabilities of most infants and small children.

Various safety closures have been suggested by the prior art which are designed to make the removal of the closure much more difficult than in the case of conventional closures. Such safety closures are primarily used on containers which are designed to be child-proof." Such closures require special manipulative techniques which are normally beyond the comprehension or physical ability of a child so that removal of the closure by a child is extremely difficult and the danger of a child removing the closure and consuming the contents of the container is substantially eliminated.

Such closures can be generally described as including a resilient sealing member which is compressed when the closure is drawn into the sealing position, a depending skirt portion adapted to fit over the neck of the container and which is provided with means for the closure into the sealing position on the container. The depending skirt portion carries one or more separate projections or lugs which are adapted to inter-engage with co operating indentations or projections on the bottle neck for interlocking to prevent reverse rotation of the closure. They are maintained in their interlocking rela tionship by the upward urging of the resilient closure liner which is compressed during the sealing procedure and which is relaxed somewhat when the closure is in sealing position. The closures are designed to be removed by a downward pressure on the closure top which allows the closure to move downwardly against the upward urging of the resilient liner and which re sults in a disengaging or unlocking of the corresponding projections or lugs so that the closure can be removed in the conventional manner.

A significant problem encountered with the prior art safety closures is found in connection with manufacturing of the closures with separate lugs or projections. The conventionally designed safety closures do not lend themselves to automated molding procedures due to the presence of the lugs or projections which are required to provide the locking feature. As is common practice in the art the closures are normally formed of thermoplastic materials by injection moulding techniques. The presence of the separate projection on the skirt portion of the closure makes removal of the closure from the mold extremely difficult. Consequently, an additional manufacturing step is required to form the projection on the closure or to remove the closure from the mold. Such steps raise the cost of manufacturing the closures and may lead to closure designs which provide the locking feature at a minimum manufacturing cost but which may sacrifice the sealing characteristics of the closure.

SUMMARY OF THE INVENTION The present invention resides in a safety closure which provides a reliable, fluid-tight seal for a container. The closure of the present invention is designed so as to lend itself to conventional injection molding procedures without special steps being required in the manufacturing process of the closure and without lessening the sealing reliability of the safety closure.

More particularly the closure of the present invention includes a depending skirt portion provided with a thread on the interior surface thereof engageable with the thread on the open ended neck of a container for axially drawing the closure into fluid-tight sealing en gagement with the open end. Locking means is integrally formed as part of the thread of the closure and the locking means is adapted to cooperate with locking means provided on the thread of the neck of the container to lock the closure on the neck of the container. The closure is removed by application of sufficient force on the top portion thereof to move the closure downwardly with respect to the neck of the container thereby releasing the cooperating locking means and allowing the closure to be rotatably removed from the container neck.

In accordance with the present invention, the locking means on the thread of the closure is located adjacent the start end of the thread and is formed as a part of the thread in such a manner as to provide for ready removal of the mold core from the closure during the manufacturing process. The thread design of the closure provides fluid-tight sealing associated with threaded closure combined with the aforementioned safety feature.

Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of a closure constructed in accordance with the present invention showing a portion of the interior thereof, and the exterior portion of the neck of a container with the remaining portion of the container broken away for compactness of illustration;

FIG. 2 is a side view, partially in section and partially broken away for compactness of illustration, illustrating the closure of the present invention as it is drawn into sealing engagement with the open end of the neck of the container;

FIG. 3 is a side view, partially in section and partially broken away for compactness of illustration, showing the closure of the present invention in the sealing position on the neck of the container and with the cooperating locking means in engagement; and

FIG. 4 is a side view, partially in section and partially broken away for compactness of illustration, illustrating the closure of the present invention in the downward unlocked position prior to removal of the closure from the neck of the container.

DETAILED DESCRIPTION OF THE INVENTION As shown in the drawings, the invention is embodied in a safety closure, shown generally as 11, adapted to be threadedly engaged with a neck portion 12 of a container l3 and for being axially drawn into sealing en gagement with an open end 14 of the neck portion 12. The closure 11 includes a continuous thread I6 which is formed with an enlarged start end portion 17 and a shoulder 18 which is adapted to engage with a cooperating shoulder 19 carried by a thread 2] provided about the neck 12 of the container 13.

As is more specifically illustrated in FIG. 1, there is shown a part of the container 13 including the cylindrical neck 12 and the open end 14 thereof. The thread 2| provided around the exterior surface of the neck 12 defines a lower face 22 on which is provided a lug 23 defining a camming surface 24 which terminates at the shoulder 19.

The closure 11 comprises a top 26 and a cylindrical depending skirt 27 adapted to be received over the cylindrical neck 12 of the container 13. The interior surface of the top 26 is provided with a resilient sealing member 29 comprising a layer 31 of resilient compressible, elastomeric material such as for example foamed polyurethane, neoprene rubber or the like and a fluid impervious, flexible outer layer 32 adapted to fit around the open end 14 to form a fluid-tight seal therewith when the closure ll is drawn into the sealing position.

The closure thread 16 is carried about the interior surface of the depending skirt 27 of the closure ll and forms one or more helical turns thereabout. The thread 16 extends radially inwardly from the skirt 27 to define the upper face 28. The start end portion 17 is integral with and forms a part of the thread 16. The start end portion 17 is enlarged with respect to the remaining portion of the thread in a direction normal to the longi tudinal axis of the thread so that the upper face 28a of the start end portion beginning at the start of the thread is contained in a plane disposed above the plane of the upper face 28 of the remaining portion of the thread. The shoulder 18 is formed at the juncture of the start end portion 17 and the remaining portion of the thread 16 and extends between the

upper faces

28 and 28a.

The enlarged start end portion 17 is an essential feature of the thread 16 and, by its unique design, facilitates the manufacture of the closure by injection molding techniques. Thus, in accordance with standard injection molding techniques, the closure is formed by injection of thermoplastic material into a cavity defined between an outer mold portion and a mold core. The mold core includes an axial groove which corresponds to the thread 16, including an enlarged portion corresponding to the start end portion 17, to the mold cavity for the thread. In accordance with the design of the thread 16, the mold core is readily removed from the closure 11 by simply rotating the mold core with respect to the closure allowing the thread to cooperate with the axial groove to urge the mold core out of the interior of the closure. Such a removal operation is not practicable when the closure includes separate lugs or projections as in conventional safety closures.

The operation of the closure of the present invention is most specifically illustrated in FIGS. 24. In the drawings, the closure 11 is illustrated as being drawn into sealing engagement (FIG. 2). as in sealing engagement and the threads interlocked (FIG. 3) and in sea]- ing engagement with a downward force being applied to disengage the threads prior to removal of the closure (FIG. 4).

Referring more specifically to FIG. 2, the closure 11 is drawn into sealing engagement with the open end 14 by the camming action between the lower face 22 of the neck thread 2i and the upper face 28a of the enlarged start end portion 17 of the closure thread 16 responsive to the rotation of the closure in a clockwise direction. As the closure 11 is drawn downwardly on the neck 12, the resilient sealing member 29 is placed under compression. As shown in FlG. 3, the resilient sealing member 29, particularly the flexible outer layer 32, is deformed about the edge of the open end 14 to form a fluid-tight seal thereabout. The enlarged start end portion 17 and shoulder 18 of the closure thread 16 is moved past the shoulder 19 on the lower face 22 of the neck thread 21 and, due to the upward urging of the compressed resilient sealing member 29, the closure ll moves longitudinally on the neck 12 until the upper face 28 of the remaining portion of the closure thread contacts the lower face of the neck thread. The shoulder 18 is cooperatively engaged with the shoulder 19 to prevent removal ofthe closure 11 by reverse rotation alone. As illustrated, the resilient sealing member 29 remains sufficiently compressed and deformed to continue to provide a fluid-tight seal about the open end 14 of the neck 12.

As is more specifically illustrated in FIG. 4, the closure 11 is removed by applying a downward force against the top 26 compressing the resilient sealing member 29 and moving the closure 11 axially downwardly on the neck 12. The lower face 22 of the neck thread 21 and the

upper face

28 and 28a of the closure thread 16 are moved apart so that the upper face 280 of the start end portion 17 clears the shoulder 19 and the closure can be rotated in the opposite direction. It should be clear that the downward pressure need not be continuously maintained on the cap but need only be applied while the cap is rotated sufficiently to misalign the shoulders 18 and I9.

It should be evident that the particular manner in which the shoulder 19 is formed on the lower face 22 on the neck thread 21 is not critical. As illustrated in FIG. 1, a portion of the lower face 22 of the neck thread 21 is inclined downwardly to define the camming surface 24 and the shoulder 19. In another embodiment, as illustrated in FIG. 2, an end portion of the neck thread 21 is reduced in size as compared to the remaining portion of the neck thread to define shoulder 19.

From the foregoing it can be seen that the closure of the present invention is adopted to provide the safety lock feature and a fluid-tight seal for a container. ln accordance with the design of the closure thread, automated or semi-automated molding techniques may be employed in the manufacture of the closure. Separate operations to modify the closure for locking on the containers are avoided thereby lowering the manufacturing costs. Moreover, as the cooperating means for locking the closure and container are formed as part of the threads of the closure and container, the safety locking feature is achieved without any loss of the reliability of sealing achieved by threaded closures. It can also be seen that, in accordance with the present invention, the locking feature of the closure is not dependent upon the materials from which the closure and container are formed. Thus the container may be formed from resilient materials such as polyethylene, polypropylene or polyvinyl chloride or from substantially hard, inflexible materials such as metal or glass. The closure is preferably formed from an injection moldable material such as polyvinyl chloride or polyethylene.

I claim:

1. The combination of:

a container including a cylindrical neck having an open end;

a closure for said container having a top overlying said open end and a depending cylindrical skirt surrounding a portion of said neck adjacent said open end;

resilient sealing means carried by said closure and disposed between said top and said open end for sealing said open end;

continuous thread means carried on the exterior of said neck and the interior of said cylindrical skirt portion for engagement upon rotation of said closure to axially draw said closure into sealing relation with said open end, said thread means includmg; cooperating locking means provided on said thread means of said neck and said cylindrical skirt adapted for inter-engagement when said closure is in sealing relation with said open end, said locking means on said thread means of said cylindrical skirt defining a portion of said thread means and being formed integrally therewith.

2. The combination as defined in claim 1 wherein said thread means comprises:

a continuous radially extending thread disposed about said neck, said thread defining a lower sur face;

a continuous radially extending thread disposed about the inner surface of said cylindrical skirt portion, said thread defining an upper surface and a start end portion, said start end portion being enlarged with respect to the remaining portion of said thread so that said upper surface at said start end portion is disposed in a plane spaced above the plane of said upper surface of the remaining portion of said thread to define a shoulder at the juncture of said start end portion and the remaining portion of said thread, said shoulder being engageable with said locking means on said neck thread.

3. The combination of claim 1 wherein:

said lower surface of said neck thread includes a projection defining a downwardly extending shoulder for engagement with said locking means of said thread of said cylindrical skirt portion.

4. The combination of claim 1 wherein:

said lower surface of said neck thread adjacent the end thereof is disposed in a plane spaced upwardly from said lower surface of the remaining portion of said neck thread and a downwardly extending shoulder is defined therebetween.

5 5. The combination of claim 1 wherein:

said cooperating locking means are disposed along said neck thread and said thread of said cylindrical portion of said enclosure for inter-engagement when said closure is axially drawn into sealing relation with said open end of said container and are maintained in interengagement by the upward urging of said resilient sealing means.

6. The combination of claim 2 wherein said upper surface at said start end portion extends between the start of the thread and said shoulder.

7. A safety closure for use in combination with a container including an open-ended neck portion, a thread disposed about said neck portion, said thread carrying locking means, said closure comprising:

a top defining an outer face and an inner face, a downwardly depending cylindrical shirt portion, and a resilient sealing member on said inner face of said top;

continuous, axially extending thread means defining an upper face and a start end portion disposed on the inner surface of said cylindrical skirt for engagement of at least a portion of said upper face with said thread on said neck of said container for drawing said closure into sealing engagement with said open end of said container whereby said resilient sealing member is compressed against said innerface of said top;

cooperating locking means integrally formed as a part of said thread means comprising:

said upper face at said start end portion being contained in a plane disposed above the plane of said upper face of the remaining portion of said thread thereby to define a shoulder extending therebetween.

8. The safety closure of claim 6 wherein said upper face at said start end portion extends between the start of the thread and said shoulder.

LII

Claims

1. The combination of: a container including a cylindrical neck having an open end; a closure for said container having a top overlying said open end and a depending cylindrical skirt surrounding a portion of said neck adjacent said open end; resilient sealing means carried by said closure and disposed between said top and said open end for sealing said open end; continuous thread means carried on the exterior of said neck and the interior of said cylindrical skirt portion for engagement upon rotation of said closure to axially draw said closure into sealing relation with said open end, said thread means including; cooperating locking means provided on said thread means of said neck and said cylindrical skirt adapted for inter-engagement when said closure is in sealing relation with said open end, said locking means on said thread means of said cylindrical skirt defining a portion of said thread means and being formed integrally therewith.

2. The combination as defined in claim 1 wherein said thread means comprises: a continuous radially extending thread disposed about said neck, said thread defining a lower surface; a continuous radially extending thread disposed about the inner surface of said cylindrical skirt portion, said thread defining an upper surface and a start end portion, said start end portion being enlarged with respect to the remaining portion of said thread so that said upper surface at said start end portion is disposed in a plane spaced above the plane of said upper surface of the remaining portion of said thread to define a shoulder at the juncture of said start end portion and the remaining portion of said thread, said shoulder being engageable with said locking means on said neck thread.

3. The combination of claim 1 wherein: said lower surface of said neck thread includes a projection defining a downwardly extending shoulder for engagement with said locking means of said thread of said cylindrical skirt portion.

4. The combination of claim 1 wherein: said lower surface of said neck thread adjacent the end thereof is disposed in a plane spaced upwardly from said lower surface of the remaining portion of said neck thread and a downwardly extending shoulder is defined therebetween.

5. The combination of claim 1 wherein: said cooperating locking means are disposed along said neck thread and said thread of said cylindrical portion of said enclosure for inter-engagement when said closure is axially drawn into sealing relation with said open end of said container and are maintained in inter-engagement by the upward urging of said resilient sealing means.

7. A safety closure for use in combination with a container including an open-ended neck portion, a thread disposed about said neck portion, said thread carrying locking means, said closure comprising: a top defining an outer face and an inner face, a downwardly depending cylindrical shirt portion, and a resilient sealing member on said inner face of said top; continuous, axially extending thread means defining an upper face and a start end portion disposed on the inner surface of said cylindrical skirt for engagement of at least a portion of said upper face with said thread on said neck of said container for drawing said closure into sealing engagement with said open end of said container whereby said resilient sealing member is compressed against said innerface of said top; cooperating locking means integrally formed as a part of said thread means comprising: said upper face at said start end portion being contained in a plane disposed above the plane of said upper face of the remaining portion of said thread thereby to define a shoulder extending therebetween.