GB2357279A

GB2357279A - A screw-on, twist-off, tamper-evident cap that is easy to open

Info

Publication number: GB2357279A
Application number: GB0027687A
Authority: GB
Inventors: Connor Sean T O
Original assignee: Merck and Co Inc
Current assignee: Merck and Co Inc
Priority date: 1999-11-16
Filing date: 2000-11-13
Publication date: 2001-06-20
Also published as: GB0027687D0

Abstract

A tamper-evident cap 30 comprises a top, cylindrical side walls 32 with gripping means 34, a circumferential skirt 22 of greater diameter than the side walls and an outer circumferential tamper-evident ring 24. The inner face of the outer ring is provided with at least four frangible bridges or posts 26 and wiper blade-like projections 28. The posts are angled so as to permit the high-speed, high-torque application of the cap whilst reducing the torque required to rupture the posts upon initial removal of the cap. The blade-like projections transmit force applied to the outer ring in a cap removing direction to the inner skirt.

Description

2357279

TITLE OF TBE INVENTION

TANTER EVIDENT CAP BACKGROUND OF THE INVENTION

Tamper evident caps are used to indicate to a prospective purchaser whether a container has been tampered with. Several approaches are in use, ranging from tear bands whose removal indicates a cap has been unthreaded to plastic shrink bands that must first be tom off to unscrew the cap. These designs serve not only as tamper indicators, but as deterrents to pilferers.

One drawback of many of these prior approaches is the need for special capping machinery in order to mount the tamper evident cap on the container. Often, the cap is applied at such speed and torque that the tamper evident cap is damaged and cannot be used.

In the past, the problem of cap failure during capping has been solved by having an operator manually cap the bottle. Another solution that has been tried is to decrease the torque and rotation speed of the capping machinery so as to initiate closure, after which an operator completes the seal manually. However, these are not viable solutions in a commercial environment because the cost and the lack of efficiency of using operators in lieu of machinery makes such a solution impractical.

A further problem with prior tamper evident cap designs is that a large amount of force was needed to rupture the posts and open the sealed container.

Certain consumers, such as senior citizens, often have difficulty opening the containers because of the force required.

The tamper evident cap post design of the instant invention solves this problem. The instant invention relates generally to a tamper evident cap with a post design that allows for high-speed application, requires only minimal force to remove the cap, and includes flexible wiper blade-like torque transmitting means.

Currently, there is no known post design that effectively addresses the problems associated with the capping and removal process. Tamper evident caps are well known in the art, however, none have a design that successfully addresses 20304 the problems associated with high-speed application of the cap onto the container and easy removal of the cap by the consumer. Different kinds of tamper evident caps are known including those disclosed in U.S. Patents Nos. 4,801,029, 5,456, 375 and 5,720,402.

Accordingly, there is a need in the industry for a tamper evident cap design that will allow for high-speed application under stressed conditions, while permitting easy removal by the consumer. The post design of the instant application satisfies the above criteria.

Thus, the primary object of the instant invention is a tamper evident cap designed to permit high speed and high torque application of a cap in an automated filling line setting, while preserving the tamper evident elements of the cap and allowing easy removal of the cap by the consumer.

SUMMARY OF THE INVENTION

There is disclosed a tamper evident cap having flexible wiper blade projections and a unique post design. The claimed cap design allows the sealing of containers under the high-speed and high torque conditions of a filling line, without damage to the tamper evident element of the cap.

The tamper evident cap comprises a cap having a top and cylindrical walls, said walls having inner and outer faces and being fixedly secured to said cap, an inner face of said cylindrical wall having helical screw threads, said threads being formed so as to permit said wall to mate with the counter-threaded neck of a container; a skirt fixedly and integrally secured to the bottom of said wall, said skirt circumferentially encircling and contacting said wall, said skirt having a diameter larger than the diameter of said cylindrical wall; grip enhancers disposed on the outer face of said cylindrical wall; an outer circumferential ring encircling said skirt and being removable after rupture of a plurality of posts, said outer ring having an inner circumferential area and an outer circumferential area, said ring being located in a plane below said skirt, said outer ring being connected to said skirt by at least four posts extending between said skirt and said outer ring, said posts being rupturable 20304 in response to application of torque to said outer ring in a cap removing direction; and said outer ring having wiper blade-like projections spaced around the inner circumferential area of said outer ring. The posts include both stress enhancing and stress reducing geometries. The stress reducing geometry of the posts permits high-speed capping without failure of the posts, while the stress enhancing geometry simultaneously permits easy rupture of the posts when force is applied to a sealed container in a cap removing direction.

Flexible wiper blade-like projections are also included in the cap design and function to transmit torque when force is applied to the cap of a sealed container in a cap removing direction. The wiper blade-like projections are fixedly secured to the outer ring and extend inwardly from the outer ring, stopping just short of the skirt itself. The flexible nature of these projections allows them to accommo date variations in tolerance of the finish lugs on the closure of a container, thereby preventing the breaking of posts during capping.

BRIEF DESCRIPTION OF THE DRAWINGS

The instant invention will be more fully understood in the following detailed description, it being understood, however, that the invention is not confined to the precise disclosure. Changes and modification may be made that do not affect the spirit of the invention, nor exceed the scope thereof, as expressed in the appended claims. Accordingly, the instant invention will now be described with particular reference to the accompanying drawings.

Figure 1 is a top plan view of the tamper evident cap and post design.

Figure 2 is a sectional view of the cap and post design and shows the details of the construction of the cap and post design.

Figure 3 is an enlarged view of the posts as they are secured to the inner and outer circumferential bands.

20304 DETAKED DESCRIPTION OF TBE INVENTION

There is disclosed a tamper evident cap with posts comprising a top and cylindrical walls, said walls having inner and outer faces and being fixedly secured to said cap, an inner face of said cylindrical wall having helical screw threads, said threads being formed so as to permit said wall to mate with the counter-threaded neck of a container; a skirt fixedly and integrally secured to the bottom of said wall, said skirt circumferenti ally encircling and contacting said wall, said skirt having a diameter larger than the diameter of said cylindrical wall; grip- enhancers disposed on the outer face of said cylindrical wall; an outer circumferential ring encircling said skirt and being removable after rupture of a plurality of posts, said outer ring having an inner circumferential area and an outer circumferential area, said ling being located in a plane below said skirt, said outer ring being connected to said skirt by at least four posts extending between said skirt and said outer ring, said posts being rupturable in response to application of torque to said outer ring in a cap removing direction; and said outer ring having wiper blade-like projections spaced around the inner circumferential area of said outer ring.

Reference is made to the drawings wherein like numerals designate corresponding or similar elements throughout the several views. Figure I. a shows one embodiment of the cap and post design. There is provided a tamper evident cap, generally identified as 20. Cap 20 includes a skirt 22 and an outer ring 24 which are joined together by a set of bridges in the form of breakable posts 26 which extend radially, generally in the plane of skirt 22 and between skirt 22 and outer ring 24.

There are also a series of wiper blade-like projections 28 attached to outer ring 24 and extending inwardly from the outer ring 24 reaching just short of skirt 22. Cap top 30, which has an interior and an exterior face, is also shown. Cap 20 is formed by molding, and preferably by injection molding. A disc made of polyethylene or polypropylene or a similar substance (not shown) may be fitted to the interior face of cap top 30 and positioned thereupon. The disc prevents the contents of a container sealed with the tamper evident cap from contacting the molded plastic of the cap itself.

20304 Cylindrical wall 32 is seen in Figure 1b, a side view of cap 20.

Cylindrical wall 32 has a plurality of raised gripping structures 34 spaced equi distantly around the wall. Grip enhancers 34 aid in opening a container sealed with cap 20 by facilitating easy gripping of the cap. Grip enhancers 34 extend away from skirt 22 and end short of cap top 30. Cylindrical wall 32 intersects cap top 30 to form a union. Cylindrical wall 32 also has helical screw threads disposed on its interior face (not shown).

Figure I c shows an enlarged view of the unique post design. In this view, the stress enhancing 36 and stress reducing 38 geometries of the posts are shown. Stress enhancing notch 40 is indicated. Wiper blade-like projections 28 are also shown.

Figure 2 shows a detailed view of the unique post design. The stress enhancing 36 and stress reducing 38 post geometries of the posts are shown. Outer ring 24, skirt 22, and wiper blade-like projections 28 are also shown. Post 26 bridges the space between the cap and rupturable outer ring 24. The stress reducing design 38 is the key to the high-speed application of cap 20. Stress enhancing notch 40 is indicated and is the key to easy rupture of posts 26 and removal of cap 20. The stress reducing 38 post geometries impart to posts 26 an added degree of stability, which makes it possible for cap 20 to be installed at high speeds on containers having finish lugs, without damage to outer ring 24. Stress reducing geometry 38 bolsters the post against force applied in a cap tightening direction.

Figure 2 shows that the geometry of the stress enhancing structures 36 form an instance of low post strength, indicated as stress enhancing notch 40. This fracture point makes it easier for the posts to be ruptured when force is applied in a cap removing direction. Thus, a consumer opening a container sealed with cap 20 needs to apply significantly less force in a cap removing direction to rupture post 26 and open the container.

Wiper blade-like projections 28 are also shown. These projections are flexible and extend inwardly from outer ring 24 reaching just short of skirt 22.

Caps having a solid lug design have the associated problem that they are inflexible 20304 and rigid. Caps having a solid lug design are an effective means of transmitting force when torque is applied in a cap removing direction. When such a cap is torqued onto a container having finish lugs spaced around the container's neck, the cap's lug containing structure often fails. Failure of the cap's lug containing structure is a result of both the high torque applied during sealing and the cap's inability to accommodate the frequent variations in tolerance of the finish lugs on the container neck. These variations in tolerance arise during the manufacture of the container. The cap of the instant invention, however, solves this problem by including flexible wiper blade-like projections 28. These projections are flexible and can therefore accommodate high torque application and variations in container finish lug tolerance. It is to be under stood that the outer ring 24 is of a circumference so as to completely encircle the neck of the container.

Breakable posts 26 are shown more specifically in Figure 3. There are at least four posts attached to the inner and outer rings, although only one quarter of the outer ring 24 is shown in Figure 3. The posts are of a stress reducing and stress enhancing design. In particular, they are molded to include a stress enhancing notch on one side and a straight stress reducing design 38 on the opposite side. This unique design is what imparts the ability of the cap to be applied to a container using automated high-speed equipment without breaking posts 26 during application. The design also permits the cap to be removed by applying significantly less force than other tamper evident caps. Finish lugs 8 are shown in Figure 3, as well as a section of skirt 22.

Flexible wipers blade-like projections 28 are also shown. The orientation of the wiper blade-like projections 28 relative to the finish lugs 8 on the container is shown in Figure 3. The positioning and design of wiper blade-like projections 28 and finish lugs 8 also shows the nature of the problem the instant invention addresses. If the torque-generating means are not flexible, distortion and rupture of outer ring 24 will occur when the cap is affixed to a container as the ring must pass over the solid finish lugs several times in order to be effectively fastened to the container.

20304 Once it is decided to open the container, the wiper blade-like projections will receive in compressive relation the torque from the outer ring 24 and direct said torque to finish lugs 8. Applying sufficient force to outer ring 24 to effect the rotation thereof leads-to rupture of posts 26 and subsequently permits the removal of the tamper evident cap 20 and open the container. If there is any turning of the member 20 in a cap removing direction and the rotation and torque applied is sufficient, before skirt 22 is turned, the rupturable posts 26 will fail. It will be seen that outer ring 24, upon which wiper blade-like projections 28 are mounted, remains in contact with the neck of container 10 until posts 26 are ruptured, after which the ring may be removed by the consumer. The benefits of the claimed post design geometry are threefold. First, the stress reducing geometry of post 26 enables cap 20 to withstand the high torque applied during the capping process. Second, the stress enhancing geometry of post 26 permits the post to rupture easily, thereby requiring less torque to open the capped container. Third, the flexible wiper bladelike projections 28 allow the cap to accommodate variations in tolerance of the container finish lugs. Together, these elements form a tamper evident cap 20 which is able to withstand the high stress that accompanies a high-speed, high torque capping process, but at the same time is an effective indicator of tampering and is easy for a consumer to open. Engineering studies performed on the claimed cap design have confirmed the need for less force when opening a container sealed with the claimed cap design.

The principles, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. The embodiments are to be construed as illustrative rather than restrictive. It is recognized, however, that departures may be made therefrom within the scope of the invention, and that obvious modifications may occur to a person skilled in the art, and that the metes and bounds of the invention are to determined solely from the appended claims.

20304 WHAT IS CLAMED IS:

1 A tamper evident cap with posts and a screw threaded closure comprising:

a) a cap having a top and cylindrical walls, said walls having inner and outer faces and being fixedly secured to said cap, an inner face of said cylindrical wall having helical screw threads, said threads being formed so as to permit said wall to mate with the counter-threaded neck of a container; b) a skirt fixedly and integrally secured to the bottom of said wall, said skirt circumferentially encircling and contacting said wall, said skirt having a diameter larger than the diameter of said cylindrical wall; c) grip-enhancers disposed on the outer face of said cylindrical wall; d) an outer circumferential ring encircling said skirt and being removable after rupture of a plurality of posts, said outer ring having an inner circumferential area and an outer circumferential area, said ring being located in a plane below said skirt, said outer ring being connected to said skirt by at least four posts extending between said skirt and said outer ring, e) said posts being rupturable in response to the application of torque to said outer ling in a cap removing direction; and f) said outer ring having wiper blade-like projections spaced around the inner circumferential area of said outer ring.

Claims

2. The cap as described in Claim 1 wherein there are four posts extending

between the skirt and the ouer circumferential ring.