GB2149765A

GB2149765A - Tamper evident closures

Info

Publication number: GB2149765A
Application number: GB08428738A
Authority: GB
Inventors: Frank S Nixdorff
Original assignee: Anchor Hocking LLC
Current assignee: Anchor Hocking LLC
Priority date: 1983-11-14
Filing date: 1984-11-14
Publication date: 1985-06-19
Also published as: BE901042A; FR2554791A1; GB2149765B; IT1178230B; IT8449156A1; LU85640A1; IT8449156A0; NL8403450A; JPS60172662A; DE3441431A1; GB8428738D0

Abstract

A tamper evident moulded closure cap (1) for sealing containers has an integrally moulded tamper indicating band (4) with a flared portion at the line of weakness (13) between the cap skirt and the tamper indicating band. The flare facilitates the cap moulding. As the container is sealed, the indicating band passes over a bead on the container having several outwardly projecting stops. When the cap is unscrewed the stops engage cooperating stops on the indicating band causing it to be torn loose. Each of the stops has one inclined flank to permit the cap to be screwed on to the container and one radial flank to resist rotation of the indicating band when the cap is unscrewed. The cap is moulded in moulding means comprising a cavity (17) and a complementary core (16) and sleeve portion (18), the sleeve portion having a shaping portion (20) to form the inner surface of the indicating band. A flared outer edge (22) of the sleeve portion (18) produces the line of weakness. <IMAGE>

Description

SPECIFICATION Tamper evident closures This invention relates to moulded plastic closure caps for containers such as food packages and the like. More particularly, this application relates to such a closure cap having an integrally moulded tamper indicating band which is formed with the closure and which is applied to the container with the closure cap during a normal sealing operation.

This band is torn off the closure cap when any attempt is made to open the package including unauthorized or accidental partial or complete removal during shipment or during display in stores.

There are a number of closure caps of this general type including aluminium closures and a number of moulded plastic closures. The aluminium closures normally require a separate step during the package sealing when the tamper indicating bands are rolled onto the container finish. Prior moulded plastic closure caps have been designed having tamper indicating bands which are applied directly with the closure as the closures are turned onto the containers. These closures have experienced problems, including difficulties in manufacturing the closures with satisfactory band defining score lines or other lines of weakness. Difficulty has also been encountered in using separate scoring means or has been encountered in the cap making dies where an excessive number of parts have been required in the dies and excessive die wear is encountered in producing these caps.

According to one aspect of the present invention, a closure cap for sealing a container has a skirt with thread formations to engage thread formations on the container, a tamper indicating band extending below the skirt and connected to the skirt by frangible means, and projections on the inner surface of the band adapted to engage projections on the container to resist rotation of the band relative to the container on rotation of the cap relative to the container in an unscrewing direction.

According to a second aspect of the present invention, a unitary moulded plastic closure cap for sealing a container having a threaded neck has a cover and a depending skirt having container engaging threads on its inner surface and a tamper indicating band extending downwardly from the lower edge of the skirt, at least the upper portion of the band flaring outwardly, a plurality of bridge members extending between the flared tamper indicating band and the lower portion of the skirt, a slot extending around the closure cap between the bottom of the skirt and the top of the tamper indicating band, and a plurality of inwardly projecting stops on the inner surface of the tamper indicating band for engaging cooperating stops on the container.

According to a third aspect of the present invention, a sealed package comprises the combination of a container with closure engaging threads at its mouth and a moulded plastic closure cap sealing the container and having a cover and a depending skirt with threads on its inner surface engaging the container threads with a tamper indicating band extending downwardly and outwardly from the lower edge of the skirt and a plurality of bridge members extending between the tamper indicating band and the lower portion of the skirt, a circular slot extending around the closure cap between the bottom of the skirt and the top of the tamper indicating band, the bridge members being positioned to bridge the slot, a plurality of inwardly projecting stops on the inner surface of the tamper indicating band, and a bead on the container below the container threads having closure engaging stops for engaging the closure stops during closure cap removal. Preferably, the stops on the band and/or the stops on the container have opposite flanks of different inclination to provide a ratcheting effect on relative rotation between the cap and the container.

The invention may be carried into practice in various ways but one closure cap embodying the invention in certain of its aspects and moulding means for making that cap and a modified cap and embodying the invention in other of its aspects will now be described by way of example with reference to the accompanying drawings, in which:: Figure 1 is a perspective view of a package sealed with a closure cap in accordance with the present invention; Figure 2 is an exploded perspective view illustrating the closure cap prior to application onto a preferred container finish; Figure 3 is a side elevational view of the package of Figure 1; Figure 4 is a horizontal sectional view taken along line 4-4 on Figure 3; Figure 5 is an exploded perspective view illustrating the closure cap removed from the container; Figure 6 is a vertical sectional view taken along line 6-6 on Figure 3; Figure 7 is a vertical sectional view taken along line 7-7 on Figure 5; Figure 8 is a vertical sectional view of a preferred means for moulding the closure cap shown in the preceding figures; Figure 9 is an enlarged vertical sectional view of a portion of the moulding means of Figure 8;; Figure 10 is a horizontal sectional view taken along line 10-10 on Figure 9; and Figure 11 is a vertical sectional view of an alternative form of moulding means.

Figures 1 to 7 show a one piece moulded closure cap applied to a glass container although it could be applied to containers of other forms and of other materials such as plastics. The cap includes an integral tamper indicating band which, as will be more fully described below, is moulded at the same time as the rest of the closure cap. The band is removably attached to the lower portion of the closure cap skirt. The band cooperates with members provided at the mouth of the container so that it is torn clear of and drops downwardly from the cap skirt when the closure cap is turned during cap removal. This prompt detachment of the band thus gives an immediate indication when anyone intentionally or accidentally loosens the closure cap.

There is thus a prompt indication that the package seal may have been destroyed as someone has partially or fully removed the closure. The final purchaser is protected by this indication and can reject questionable packages and select a fully sealed satisfactory package.

The closure cap 1 has a cover 2 and a depending skirt 3 and an integral tamper indicating band 4 extending downwardly from the lower edge of the skirt 3. The inner surface of the cap skirt 3 has container engaging means such as the continuous threads 5 or other twist type container engaging members. Cooperating closure engaging means such as the continuous threads 6 or other twist type closure engaging means are provided at the top of the container 7.

A band engaging ring 8 is formed on the top of the container 7 below the threads 6. This outwardly extending ring 8 includes a number of projections in the form of spaced stops 9 which project radially outwardly for engaging cooperating projections in the form of stops 10 formed on the inner surface of the tamper indicating band 4. The stops 9 on the container have tapered surfaces 11 which are inclined outwardly, as best illustrated in Figure 4, to pass the correspondingly tapered stops 10 on the tamper indicating band 4 in a ratchet-like action when the closure cap 1 is screwed onto the container 7. The opposite sides of the stops to the tapered edges on the container stops 9 and on the band stops 10 project generally radially with regard to the container mouth and the band.Thus, when the cap 1 is turned off the container 7, the stops 9 and 10 lock together preventing relative rotation of the band 4 with respect to the container 7, causing the band 4 to be broken clear of the closure cap skirt 3 as frangible means in the form of connecting bridges 12, which attach the band 4 to the skirt 3, are fractured.

A circular slot or line of weakness 13 is formed during the closure cap moulding to separate the band from the cap skirt and several of the spaced connecting bridges 12 removably attach the band 4 to the skirt 3. In the embodiment illustrated in Fig ures 1 to 7 for example, there are eight bridges 12 generally equally spaced around the circumference of the cap skirt 3 and band 4 and positioned outwardly of the slot 13 on the skirt 3 and band 4 outer surfaces.

As best illustrated in Figures 6 and 7, the bridges 12 extend downwardly from the lower outer portion of the skirt 3 and over the band 4 which leaves a full 360 slot extending around the closure cap 1 between the lower edge of the skirt 3 and the top of the band 4 with portions of the slot 13 passing behind each of the bridges 12.

Figure 2 illustrates the closure cap 1 just prior to its application to a filled container 7. The cap 1 is turned downwardly onto the container 7 until a seal is achieved between the container and sealing fins 14 on the underside of the closure cap cover 2.

The tamper indicating band 4 passes downwardly over the ring 8 and the stops 9 and 10 slip over one another. The relationship of the cap 1 and the container threads 5 and 6 and the band 4 and stops 9 and 10 is arranged so that the stops 10 on the band 4 and stops 9 on the container 7 are spaced from one another for the fully sealed position. In the embodiment illustrated, the provisions of four stops 9 and four stops 10 results in band 4 separation when the cap 1 is turned 90 or less and so that the tamper indication is obtained before the cap 1 has been turned more than a small portion of its full number of removal turns.

In order to provide for a relatively easy and high speed manufacture of the closure caps, the caps are formed in a single moulding step. The entire closure cap 1, including the cover 2 and skirt 3 and the tamper indicating band 4, are formed in the single moulding.

One particular die arrangement which may be used for moulding the cap shown in Figure 1 including simultaneously moulding the band 4 including the spaced stops 10 and the circular slot 13 is illustrated in Figures 8 and 9 where the cover and skirt moulding core is illustrated at 16 within a mould cavity 17. The core includes a slot and band forming core sleeve portion 18. Vertical slots 19 in the die cavity 17 are provided to accept plasic material from a port 23 via the cap skirt portion 3 as the closure is moulded to form the several spaced bridges 12 which project outwardly of the lower portion of the skirt 3 and the outer surface of the band 4 (Figure 10). The sleeve portion 18 has an inner band surface shaping portion 20 including spaced cutouts 21 for forming the spaced stops 10 on the inner surface of the band 4.A flared outer edge 22 on the sleeve portion 18 is positioned to move towards and against the parallel flared surface of the cavity 17. The flared edge 22 seals against the flared cavity 17 surface at all points other than at the slots 19 provided for the bridges 12 and in so doing blocks off the plastic and provides for the formation of the circular slot 13.

Prior dies of this general type have slot forming edges which are moved into sliding contact with angularly aligned or generally perpendicular mould cavity surfaces. This motion in high speed moulding machines tended to wear the edges of the dies and to dull them after a relatively short time resulting in a failure of the die to form complete and open slots.

The flared edge 22 of the above described sleeve 18, when moved downwardly within the cavity 17, (i.e. towards the closed end of the cavity) is moved into contact with a correspondingly flared cavity surface without sliding contact and its resultant friction. Contact is, therefore, made at the instant that the flared edge 22 reaches its lowermost position on the cavity 17 surface without movement of the beveled edge 22 over or along the cavity 17 surface. This essentially eliminates all edge wear and permits the die to form the circular slots 13 for indefinite periods.

Figure 11 shows an alternative form of closure cap 30 having a differing placement of the bridges connecting the cap skirt to the tamper indicating band. In this embodiment, the bridges 31 are placed within the circular slot 32 forming the line of weakness between the cap skirt 33 and the indicating band 34.

The bridges 31 between the cap skirt and the tamper indicating band 34 are formed by plastic which passes through a number of circumferentially spaced slots 35 formed in the edge of the core sleeve 36. This embodiment takes advantage of the above described flaring of the cap skirt 33 at the slot 32 permitting the slot forming surface 37 on the cavity and on the core sleeve 36 to be tapered and formed as sections of a cone and as already described above. Such surfaces are readily manufactured with the necessary dimensioning and tolerances on the die cavity surface 37 and on the core sleeve 36.When the die operates to mould the closure cap these generally parallel and conical surfaces are moved together to form an adequate moulding down because of the accurate dimensions resulting from the use of the complementary conical sections and because they come together within the die without excess sliding or contact.

The above described die arrangement thus not only permits a high speed cap moulding action in forming perfect closure caps, but also permits a simple die design which may be used without repair or replacement over extended operating periods. These advantages reduce the cost of the closure caps by minimizing die maintenance and by permitting a high speed moulding operation which produces perfectly moulded closure caps.

It will be seen that an improved tamper evident closure cap has been described which has a damage resistant construction and which also has a pleasing and compact shape or form. The tamper indicating band operates after only minor movement of the closure cap to provide a clear tamper indication where even only a partial removal has been attempted on the closure cap.

In addition, a preferred method and means for manufacturing the cap and particularly for forming the tamper indicating bandgroove or slot has been described which permits high speed closure cap manufacture with minimum die wear. Such dies provide substantial cost savings in the manufacture of the closure cap.

Various modifications may be made to the closure cap and moulding means described. For example, although the cooperating thread formations are in the form of continuous threads on both the cap and the container, either or both may be replaced by discontinuous lugs. Also, although both the stops on the band and the stops on the container are described as having an inclined flank and a radial flank other profiles for one or both may be possible.

Claims

1. A closure cap for sealing a container, the cap having a skirt with thread formations to engage thread formations on the container, a tamper indicating band extending below the skirt and connected to the skirt by frangible means, and projections on the inner surface of the band adapted to engage projections on the container to resist rotation of the band relative to the container on rotation of the ci p relative to the container in an unscrewing direction.

2. A unitary moulded plastic closure cap for sealing a container having a threaded neck, the closure having a ccver and a depending skirt having container engaging threads on its inner surface and a tamper indicating band extending downwardly from the lower edge of the skirt, at least the upper portion of the band flaring outwardly, a plurality of bridge members extending between the flared tamper indicating band and the lower portion of the skirt, a slot extending around the closure cap between the bottom of the skirt and the top of the tamper indicating band, and a plurality of inwardly projecting stops on the inner surface of the tamper indicating band for engaging cooperating stops on the container.

3. A closure cap as claimed in Claim 2 in which the container engaging threads comprise continuous threads.

4. A closure cap as claimed in Claim 2 or Claim 3 in which the stops on the band have inclined surfaces on their leading edges as screwed on to pass easily over the container stops, and generally radially directed opposite edges to engage the container stop when being screwed off to tear off the band.

5. A sealed package comprising the combination of a container with closure engaging threads at its mouth and a moulded plastic closure cap sealing the container and having a cover and a depending skirt with threads on its inner surface engaging the container threads with a tamper indicating band extending downwardly and outwardly from the lower edge of the skirt and a plurality of bridge members extending between the tamper indicating band and the lower portion of the skirt, a circular slot extending around the closure cap between the bottom of the skirt and the top of the tamper indicating band, the bridge members being positioned to bridge the slot, a plurality of inwardly projecting stops on the inner surface of the tamper indicating band, and a bead on the container below the container threads having closure engaging stops for engaging the closure stops during closure cap removal.

6. A package as claimed in Claim 5 in which the container threads and the closure threads comprise continuous threads.

7. A package as claimed in Claim 5 or Claim 6 in which the stops on the band have inclined surfaces on their leading edges as screwed on to pass easily over the container stop and generally radially directed opposite edges to engage the container stop when being screwed off to tear off the band.

8. A package as claimed in Claim 5 or Claim 6 or Claim 7 in which the stops on the container bead have inclined surfaces on their leading edges for passing the band stops while the closure is being screwed on and have radially directed opposite surfaces to engage the closure stops when the closure is being screwed off to tear off the closure band.

9. A sealed package as claimed in Claim 5 in which the stops on the band and'our the stops on the container have opposite flanks of different inclination to provide a ratcheting effect on relative rotation between the cap and the container.

10. Means for moulding a closure cap having a cover and a depending skirt with a tamper indicating band attached to the skirt at a generally circular line of weakness, the moulding means having a closure shaping cavity and a cooperating moulding plunger, the cavity having a flaring side wall for shaping flared portions of the closure cap, and the plunger having a slot member thereon having a flared edge for being positioned opposite the said flared cavity side wall for cooperating therewith to form the said closure line of weakness.

11. Moulding means as claimed in Claim 10 in which the slot forming member on the plunger has a flared surface parallel to the cavity side wall surface for forming an open slot in the closure.

12. Moulding means as claimed in Claim 10 or Claim 11 which further comprises a sleeve mounted on the moulding plunger, the slot forming member being on the sleeve.

13. A closure cap substantially as described herein with reference to Figures 1 to 7 of the accompanying drawings.

14. A sealed package comprising the combination of a container and a closure cap thereon, substantially as described herein with reference to Figures 1 to 7 of the accompanying drawings.

15. Means for moulding a closure cap substantially as described herein with reference to Figures 1 to 10 or to Figures 1 to 10 modified as described herein with reference to Figure 11 of the accompanying drawings.