EP0052804B1

EP0052804B1 - Pilferproof cap

Info

Publication number: EP0052804B1
Application number: EP81109239A
Authority: EP
Inventors: Robert Melvin Chartier; Jean Papineau Richard
Original assignee: Consumers Glass Co Ltd
Current assignee: Consumers Glass Co Ltd
Priority date: 1980-11-24
Filing date: 1981-10-29
Publication date: 1986-02-05
Also published as: EP0052804A1; CA1153335A; AU7776381A; AU543421B2; DE3173739D1; JPS57114452A

Description

This invention relates to a pilferproof cap according to the pre-characterizing part of claim 1.
Such a known pilferproof cap is disclosed for example in DE-A-1 955 047. This known pilferproof cap comprises a drive arrangement consisting of sawtooth-shaped projections, said projections being integrally formed in the cap body portion and the band, respectively. The steep side of one projection points in the screw-on direction of the cap and mates with the matching surface of the other projection extending from the band. The projections form a driving element during application of the cap onto a shoulder of a container by controlling the force exerted on the bridges connecting the cap and the band. Upon removal of the cap from the container the projections do not engage with each other, so that the bridges will break due to the uncontrolled force applied to them.
The pilferproof cap arrangement according to DE-A-1 955 047 has the drawback that the application of caps to containers without breakage of the connecting bridges, thereby retaining the tamper-evident feature, cannot be ensured in each and every case for the following reasons:
The radius of the radially extending shoulder in the neck portion of the container differs in a certain range of tolerances. Therefore, during application of the cap onto the container the force required for urging the band over the shoulder also varies.
In nearly all cases application of the cap is carried out by high-speed-capping machines. Said machines do not handle the caps in a sensitive way, so that the danger occurs that the two steep sides of the projections are liable to be deformed, so that they are able to pass each other in slipping. The greater the resistance of the band against its movement over the shoulder, the greater the danger that the projections (subjected to strain in direction of rotation, so that additionally to the stress resulting from the rotation of the band relative to the cap, an impulse from the capping machine occurs) will be deformed.
In order to overcome the above-mentioned problems it is necessary to manufacture this known pilferproof cap arrangement very accurately with respect to the position of the projections, thereby increasing manufacturing costs.
From DE-A-2 704 461 a pilferproof cap is known, comprising a cap body portion and a band being connected with the cap body portion by means of connecting bars or bridges. In direction of rotation during application support segments are arranged in the proximity of the bridges. Thus, as the cap is applied to the container, the radially extending bridges would flex and abut the supporting segments, thereby preventing that the connecting bridges are damaged during cap application. However, during cap application the abutment of the connecting bridges with the supporting segments takes place at the sharp edge of the supporting segments and therefore the support segments could cause the connecting bridges to shear, rather than to support them and to drive the band with the cap.
It is, therefore, an object of the invention to provide a pilferproof cap of the type already known from DE-A-1 955 047 and defined in the pre-characterizing part of claim 1, said cap being applicable to a container in reproducible manner without breakage of the connecting bridges, thereby retaining the tamper-evident feature with a minimum in expense. Solution is achieved by the characterizing part of claim 1.
Under normal conditions, i.e. when the force for application is not too high, since the radii of the inner circumferential wall of the band of the cap and of the shoulder of the container, respectively, are in a correct range of tolerances, the friction between the projections integral with one of the cap body lower part and the band upper part and the planar surface of the other of said cap body lower part and band upper part is sufficient to protect the bridges from excessive stresses.
If, however, the radius of the shoulder is out of the correct range of tolerance due to inaccuracy during fabrication, a greater force is necessary for applying the cap. In this case the projections will bite into the planar surface, thereby providing a positive connection, said positive connection always being proper regardless of the momentary relative position of the band and the cap body.
The greater the force applied to the cap during application, the more the projections will bite into the planar surface. Thus, proper application of the pilferproof cap arrangement is ensured under all circumstances.
Since it is not necessary to provide a complicated shaped saw-tooth arrangement or a complicated and sensitive bridge-arrangement, as it is for example known from DE-A-1 955 047 and DE-A-2 704 461, producing of pilferproof caps according to the invention is possible with a minimum of expenses.
The subclaims contain preferred embodiments of the invention.
This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:

Figure 1 is an exploded perspective view showing the closure in preparation for application to a threaded neck of a glass bottle or container, respectively;
Figure 2 is a perspective view showing the cap and severed pilferproof band after removal from a container;
Figure 3 is a side view of the closure prior to application to a container;
Figure 4 is a partial perspective view with a portion of the cap removed illustrating the interrelationship between drive elements secured to the cap and associated bridges;
Figure 5 is a sectional view showing the closure during application to a container;
Figure 6 is a partial side view showing the closure applied to the neck of a container;
Figure 7 is a side view of the exterior of the cap during application to a container prior to the band snapping over the shoulder;
Figure 8 is an enlarged view of the bridge and drive member of Figure 7 shown as segment A;
Figures 9 and 10 are partial side views illustrating the pilferproof band and cap during removal of the cap from a container;
Figure 11 is an enlarged section of an alternate structure illustrating a portion of the band and cap with the drive means secured to the band prior to application to a container; and
Figure 12 shows the alternate structure of Figure 11 during application of the closure.

The closure generally shown as 2 in the Figures, comprises a cap body portion 4 and a depending pilferproof band 6. Means is provided in the preferred form of bridges 8 to secure or to connect the band to the cap and axially space these two components. The container 60 has been provided with a shoulder 62 which in engaging band 6 causes at least a number of bridges 8 to fracture on removing the cap. Threaded portions 64 of the container maintain the closure on the container and allow twist application and removal of the cap portion 4. As with all closures of this type, the cap portion 4 is adapted on its inside to seal the mouth 66 of the container. The threaded portion 64 in combination with the threads provided on the inner portion of cap 4, assure that the formed seal is maintained. Various well known types of seals may be used with or on the cap, such as liner inserts or various forms of fin seals. According to this embodiment, a triple fin seal 69, as shown in Figure 6, is used which engages the container rim to form a seal completely therearound.
As shown in Figure 2, the cap has been removed from the container 60 and the bridges 8 have severed or broken, due to the upward force exerted on the bridges as the cap is unscrewed while the band is constrained by interaction of the band undercut against shoulder 62. It can be appreciated that the condition of the bridges reflects whether the container has been opened and provides a simple visual indication to the consumer that the seal, provided during packaging of the product, has not been broken.
As shown in Figure 3 the outer periphery of the cap has a corrugated gripping surface to facilitate twist removal of the closure. Each of the bridges 8 has been paired with a drive 10 which is secured to the cap 4. These drives are not of sufficient height to contact the band 8 in the condition shown in Figure 3, however, during application of the closure, as shown in Figure 5, these drive members engage the band 6 and assist in limiting the amount of rotation of the band relative to the cap as the band is being applied over shoulder 62. These short drive members may be easily formed during the injection molding operation of the adjacent bridges 8.
According to Figure 4, it can be seen that the individual bridges 8 secure the cap 4 to the band 6 and keep the band and the cap essentially aligned. It can also be seen that the bridges 8 are tapered inwardly from the widest point at the junction with the band 6, to the point of junction with the cap. Also, the drives 10 have been spaced behind the bridges with respect to the direction in which the closure is screwed on a container and project downwardly from the cap 4 but do not extend or join with the band 6. The band has been provided with a sloped surface 22 to ease the application of the closure over shoulder 62 of the container and has an abutment or undercut ledge 24 for snapping beneath the shoulder during screwing of the closure onto the container. The thin sidewall 20 of the band extends upwardly from the ledge 24 and may snugly contact the exterior edge of the shoulder 62 when the closure has been applied. It has been found that in the band snugly contacting the exterior of the shoulder 62, this ensures that ledge 24 hugs the underside of shoulder 62. This is particularly useful in removal of the cap, because a snug contact assists in preventing a portion of the ledge of the band slipping over an area of the shoulder to ensure that the band stays on the container when the cap is taken off the container.
As is apparent from a review of Figures 5 and 6, surface 22 provides a camming action in leading the pilferproof band over the shoulder, whereas ledge 24 forms an essential right angle with sidewall 20 and firmly grips beneath the lower portion of the shoulder 62. Similarly, shoulder 62 has been shaped to ease application of the pilferproof band over the shoulder while providing a distinct undercut at the lower edge of the shoulder to assist in maintaining the band beneath the shoulder after application of the closure. With this arrangement, the bridges encounter less strain during application than in removal of the closure.
In Figure 7, the closure 2 is illustrated as partially applied to the container 60 with the pilferproof band engaging the upper surface of shoulder 62 as it cams against surface 22. The rotational movement of cap 4 and the engagement of lead in surface 22 with shoulder 62 have caused movement of the band towards the cap such that the drive members 10 are now engaging the upper surface of the band 6. Furthermore, due to the frictional drag of the band with the shoulder 62, some relative rotation of the cap and band has taken place causing the leading edge of drive members or teeth 10 to contact the lower trailing edge of the associated bridge 8.
Further rotation of the cap is transmitted to the band 6 by the drive members 10 engaging the thickened portion 15 of the associated bridges such that the thin area of the bridge 17, which is located adjacent the junction of the bridge with the cap, no longer has to withstand the entire force exerted on the bridges due to the drag of the band. A large portion of this force is directly transmitted to the band through the thickened portion of the bridge and the drive members 10. With further rotation of the cap, the force for snapping the band over shoulder 62 causes increased movement of the band towards the cap which enhances a biting action of the drive members on the band and the bridges. These drive members contact the area of the band below it as well as engage the thickened portion of the bridges. The sidewalls 7 of the band have sufficient axial strength to allow ledge 24 to snap over shoulder 62 without buckling to ensure consistent results.
As shown in Figures 7 and 8, the drive members have been located behind the bridges with respect to the direction of application of the closure and are spaced somewhat from the bridges to facilitate molding of these components. However, the spacing between the bridges and the drive members is preferred to be as close as possible without causing undue problems in the molding of the components. Where the space between the bridge and the drive members is greater than that shown in the drawings, the movement of the cap towards the band may cause the drive members 10 to engage with the upper surface of the band and bite into the band to prevent premature breaking of the bridges during application of the closure.
Figure 8 illustrates the biting action of a drive member 10 and the relationship of this drive member with an associated bridge 8. The movement of the cap towards the band has caused drive member 10 to engage the band 6 and cause an area of deformation 40 in the band. The cap has rotated relative to the band causing the bridge 8 to deform until the trailing edge of the bridge 8 abuts the leading edge of drive member 10. The bridge 8 normally buckles due to the movement of the cap towards the band, however, the area of increased cross section 15 is of greater strength and firmly engages the drive member 10 thereby limiting the degree of relative rotation of the cap and band. Therefore, the drive members 10 ensure bridge integrity by either engaging the associated bridges after a predetermined movement of the cap and band or by biting into the band immediately below the drive members or a combination of the two. In the preferred embodiment of Figure 8, both actions are taking place. As a result, the drives serve to transmit the torque exerted on the cap to the band to continue the rotation of the band as it snaps over the shoulder of the container.
Depending on the exact dimensions of the closure and that of the glass container, a wide range of possible combinations of closure sizes and container sizes are possible and in some circumstances, the force for snapping the band beneath the shoulder of a container will require minimum assistance from the drive members 10 engaging either the top of the band and/or the thickened portion of the bridges to successfully snap the band ledge over the shoulder. However, in other circumstances, for example, when the closure is at its smallest dimension and the diameter of shoulder 62 is at its largest tolerance, the force required to apply the band over the shoulder will be greater and this will result in further compression of the space between the upper portion of the band and the lower portion of the cap. This compressive movement results in increased biting action of the drive members 10 to thereby ensure that the thinner portions of bridges 8 do not fracture during application of the closure.
Although, each of the bridges have been provided with an associated drive member, in some cases, all of these drive members may not function. For example, accurate control on the shape of the shoulder 62 is not always possible for example, with glass finish, and this surface may depart from its preferred circular section and in fact, be oval or egg shaped. This variation in shape may cause slight side shifting of the band relative to the cap during application of the closure. However, because each of the bridges have been provided with an associated drive member, a large number of these drive members are functional and provide the necessary interaction to ensure bridge integrity during application of the closure.
As previously mentioned, the drive members, which ensure that the band rotates with the cap as the band is being forced over the container shoulder, are particularly useful in applying caps to container finishes which may vary considerably in their dimensions. It is appreciated, however, that this type of cap is useful on various types of containers which may be made of glass, metal, plastic and other suitable materials. For example, in considering glass finishes, variations in the glass finish, such as those of softdrink and liquor bottles, may be as much as 0.51 mm (20 thousandths of an inch). Whereas the tolerance on the interior dimensions of the closure are much more accurate, within approximately 0.13 mm (five thousandths of an inch). This invention, therefore, provides a tamper indicating system which permits its use with containers having a variation in bottle neck dimensions. The drive device of the system maintains the connecting means which may be in the form of bridges in unbroken condition during application of a cap to a container having these variations in dimensions.
Figures 9 and 10 illustrate removal of the cap portion from a container, both before and after, severance of the bridges 8. In Figure 9, the cap has only been rotated approximately twenty-five degrees and the threads of the bottle in combination with the threads on the interior of the cap portion have caused both an upward movement of the cap relative to the band 6 as well as a rotational movement of the band relative to the cap. Further rotation of the cap portion increases the axial separation of the cap from the band thus continuing to stretch the bridges 8 due to band ledge 24 interacting with the undercut of shoulder 62 on the bottle. This in combination with further relative rotational movement of the cap and band will eventually cause the bridges to break at thinned portion 17. Ledge 24 located in the lower portion of the band, firmly engages shoulder 62 of the closure and is of sufficient strength to cause the band to be retained on the glass finish, during removal of the cap. It can further be appreciated that because the drives 10 are located behind the bridges they are inoperable and have no affect in removing the cap such that the bridges are exposed to the combined forces due to vertical separation of the cap and band as well as rotational movement of the cap relative to the band.
Ledge 24 and shoulder 62 have been shaped to provide positive engagement during removal of the closure minimizing any tendency for ledge 24 to cam outwardly over the shoulder. The band has been thickened adjacent ledge 24 to have sufficient strength to withstand the hoop stress encountered during removal of the closure or at least until a number of bridges have severed.
It is, of course, appreciated that the relationship of the band ledge 24 relative to the sealing surface 69 of the cap is designed to ensure that, on cap removal, the connecting bridge portion 8 begins to stretch and perhaps sever before the seal 69 is completely broken. The purpose of this arrangement is particularly suitable where tampering must be indicated when the contents are subject to spoiling or degradation once exposed to air. Thus, the arrangement is such that, as soon as the seal is broken allowing air to enter, for example a vacuum packed bottle, the bridges have been sufficiently stretched or broken to indicate that the container has been tampered with. It is also understood that, in situations where exposure of the contents to air is not critical, then the relationship of the band to the sealing surface may be somewhat more lenient, which in some circumstances would allow breaking of the seal before the band bridges have been broken.
Therefore, the drive members of the present invention assist in transmitting forces encountered during application of the closure to ensure bridge integrity during application of the closure. During removal of the cap from the container, drive means are ineffective such that the bridges sever and provide a visual indication that the contents of the container have been opened. Furthermore, this drive means allows the bridges to have a tapered cross section such that the drive members engage the thickened portion of the bridges due to movement of the cap towards the band during application of the closure. This allows direct transmission of the forces between the cap and the thickened portion of the bridges while protecting the area of reduced section of the bridges which will sever, upon removal of the cap.
The alternate structure shown in Figures 11 and 12 incorporates drive members secured to the upper portion of the pilferproof band forward of the bridges with respect to the direction of application of the closure. Because the drives are now located on the band, the thickened portions of the bridges are located adjacent the lower portion of the cap such that during application of the closure, the drive members engage the thickened portion thereby protecting the thin portion of the bridges.
As shown in Figure 11, the drive 10a projects upwardly from band 6 and is spaced forward of bridge 8a. The drive is essentially short and stubby to have sufficient structural strength to positively engage the cap, as shown by deformation 40a in Figure 12 and/or provide positive engagement with the thicker portion 15a of the bridges.
In Figure 12 the closure is shown during application to a container 60 and the band has been forced to move upward such that the drive 10a is biting into the cap as shown by deformation 40a and some rotation of the cap has occurred as the deformed bridge 8a is contacting drive 10a. Further twist application of the cap will be transmitted to the band by drive member 10a due to its interengagement with the thickened portion 15a of the bridge and its engagement with the lower portion of the cap. The specialized shape of the bridge provides a simple method for controlling the force required to break them. Furthermore, the area of reduced cross section 17a deforms more readily, allowing thickened portion 15a to remain aligned with drive 10a, to provide positive engagement during application of the closure.
In some circumstances, for example, where the upper portion of the band is not as thick as the adjacent lower portion of the cap, it is preferred that the drive members be secured to the cap to ensure efficient biting of the drive members with the band. In the preferred embodiments shown in the drawings, the drive members have been paired with associated bridges such that the rotational movement of the cap relative to the band is resisted due to the interaction of the drive members with the lower portion of the band when the drive members are secured to the cap and due to the engagement of the drives with the thickened portion of the bridges. However, in some circumstances, it may not be necessary to pair these drives with the bridges as the individual biting action of the drives with either the band or the cap will be sufficient to ensure bridge integrity during application of the closure.
The present invention utilizes the inherent properties of a plastic which allows a fairly high degree of localized deformation without permanent damage. However, the particular shape of the closure and the pilferproof band utilizes these features during application of the closure in applying ledge 24 over the shoulder on a container while trying to minimize the effect of this property in maintaining the band on the container. The precise plastic selected for forming this closure will vary according to the application however, various thermoplastic materials, such as polyethylene and polypropylene have been found particularly useful with glass containers designed for the liquor industry.
Polypropylene is less deformable than some other plastics such as polyethylene however, it has proven to be quite acceptable. Furthermore, after molding, it exhibits an aging characteristic where the material becomes more brittle and less elastic. Because of this aging problem and the uncertainty in knowing when a closure will be used, it would seem this material would notfunc- tion satisfactorily however, in actual practice, it has proven quite useful. The drive means limits the forces exerted on the more brittle bridges during application of the closure and prevent premature fracture of the bridges.
When polyethylene is used, the closure is more deformable and the bridges can undergo increased deformation without breaking. Furthermore, the plastic is not as rigid as polypropylene and there is a greater tendency for the band to slide over the shoulder of a container when it is removed. To overcome this problem, the area of reduced bridge cross section 17 may be made smaller to fracture more readily while the drive members protect this thinned area during application of the closure.
It is appreciated that other plastics may be used, such as copolymers of the polyethylene/polypropylene type. In addition, mechanical blends of various polymers may be used, such as a combination of polyethylene and polypropylene. Various grades of these plastics may be used in the caps depending upon their end uses, such as, consideration for the strength requirements in the caps as used under pressure or vacuum. Depending upon the selection of a particular plastic, alterations may be required in the shape of the bridges or means for connecting the band to the cap and in the location and shape of the drives for ensuring that the band rotates with the cap, as the band is being forced over the larger part of the shoulder on a container.
In view of the above detailed description of certain aspects of the invention, it can be appreciated that with the control on band movement when the cap is being applied to a container, a broader scope in variations of container tolerances, selected cap plastic compositions and bottle capping mechanisms can be accommodated.

Claims

1. A plastic cap with tamper indicating provision for twist application to a container (60), comprising a cap body portion (4) with a central axis and having a lower part, a band (6) for application over a shoulder (62) provided on a container (60) and having an upper part which is spaced beneath and in line with said cap body lower part in a direction parallel to the axis of said cap body portion (4), means (8, 8a) connecting the cap body portion (4) and the band (6), means provided in association with said cap for controlling the force exerted on said connecting means (8, 8a) due to rotation of the cap and due to frictional engagement of the band (6) with a shoulder (62) of the container (60) during application of the cap (4) to the container (60), said control means comprising a plurality of projections (10, 10a) integral with one of said cap body lower part (4) and said band (6) upper part, the other of said cap body lower part and said band upper part having a planar surface portion (40, 40a) opposite each of the projections (10, 10a) said connecting means (8, 8a) being longer than said projections (10, 10a), so that said projections (10, 10a) are shorter than said space between said cap body lower part (4) and said band upper part (6), and said control means being actuated by rotation of said cap (4) relative to said band (6) whereby said projections (10, 10a) move towards said opposing planar surface portions, characterized in that said projections (10, 10a) are so formed that they move into abutting engagement with corresponding said opposing planar surface portions (40, 40a) when the cap (4) is rotated relative to said band (6) to attach the cap (4) to the container (60).

2. A cap according to claim 1, characterized in that said connecting means comprises a plurality of bridges (8, 8a) for connecting and axially spacing the cap body portion (4) and the band (6).

3. A cap according to claim 2, characterized in that at least a number of said bridges (8, 8a) break upon removal of the cap body portion (4) such that the condition of the bridges (8, 8a) indicates whether the container (60) has been opened or tampered with.

4. A cap according to claim 2, characterized in that said control means comprises a plurality of projections (10) integral with said cap body lower part (4) and extending downwardly to engage said band upper part planar surface portions (40) after sufficient movement of said band (6) towards said cap body portion (4) during application of said closure (2) (Figure 8).

5. A cap according to claim 2, characterized in that said control means comprises a plurality of projections (10a) integral with said band upper part (6) and extending upwardly to engage said cap body lower part (4) after sufficient movement of said band (6) towards said cap body portion (4) during application of said closure (2) (Figure 12).

6. A cap according to claims 2 to 4 further characterized in that said bridges (8) have an area of increased cross-section (15) adjacent the junction point with said band upper part (6), said projections (10) being paired with said bridges (8) and positioned behind said bridges (8) with respect to the rotational direction of application of the cap (4), said projections (10) being integral with said cap body lower part (4), each of said opposing planar portions (40) of said band (6) being adjacent said junction of the increased cross-section (15) of the bridge (8) with said band (6), such that during application of said cap (4), rotational movement of said band (6) relative to said cap body portion (4) is limited due to interengagement of a number of said projections (10) and the area of increased cross-section (15) of associated bridges (8) (Figure 8).

7. A cap according to claims 3 and 5, further characterized in that said bridges (8a) have an area of increased cross-section (15a) adjacent the junction point with said cap body lower part (4), said projections (10a) being paired with said bridges (8a) and positioned in front of said bridges (8a) with respect to the rotational direction of application of the cap (4), said projections (10a) being integral with said band upper part (6), each of said opposing planar portions (40a) of said cap body lower part (4) being adjacent said 'junction of the increased cross-section (15a) of the bridge (8a) with said cap body lower part (4), such that during application of said cap (4), rotational movement of said band (6) relative to said cap body portion (4) is limited due to interengagement of a number of said projections (1 0a) and the area of increased cross-section (15a) of associated bridges (8a) (Figure 12).

8. A cap according to claims 6 and 7, characterized in that said bridges (8, 8a) are tapered to define a weak area (17, 17a) in the form of a narrower portion for fracture of each of said bridges (8, 8a) during removal of said cap body portion (4) from a container (62), said weak areas (17, 17a) being protected by said projections (10, 10a) during application of said cap (4) to preclude premature breaking thereof (Figure 8 and 12).

9. A cap according to claim 8, characterized in that said narrower portions (17, 17a) of said bridges (8, 8a) flex during application of said band (6) over a container shoulder (62), the bridges (8, -8a) in so flexing permitting movement of said band (6) towards said cap (4) to cause said projections (10, 10a) to engage the thicker (15, 15a) portions defined by said area of increased cross-section of said bridges (8, 8a), in controlling the degree of relative rotation between cap (4) and band to protect the weaker thinner bridge portions during cap application to a container.

10. A cap according to any one of the preceding claims, characterized in that the band (6) comprises a side wall portion (7), a ledge (24) projecting inwardly from said side wall portion (7) for cooperating with a shoulder (62) on a container (60) and a bottom portion having an outwardly flared lower surface (22) for camming said ledge (24) over a container shoulder (62) during application of the closure (2).

11. A cap according to claim 10, characterized in that the band comprises a side wall portion (7), said side wall portion circumferentially contacting a container shoulder (62).

12. A cap according to claim 10 or 11, characterized in that the band (6) is sized to snugly engage a shoulder (62) provided on a container (60) after application of the closure (2).

13. A cap according to claim 10 or 11, characterized in that said band (6) is maintained on said container (60) during removal of the cap (4).

14. A cap according to any one of the preceding claims, characterized in that the cap material is selected from the group of plastic materials consisting of polyethylene, polypropylene and copolymers thereof.