CN1263508A

CN1263508A - Push-on closure

Info

Publication number: CN1263508A
Application number: CN98807134A
Authority: CN
Inventors: 罗德尼·M·德鲁伊特; 帕特里克·M·弗朗; 克莱夫·巴斯韦尔
Original assignee: Closures and Packaging Services Ltd
Current assignee: Closures and Packaging Services Ltd
Priority date: 1997-07-14
Filing date: 1998-07-03
Publication date: 2000-08-16
Anticipated expiration: 2018-07-03
Also published as: ID24834A; EP1028901A1; NO20000156D0; JP2001510124A; NO20000156L; HUP0004155A2; PL338128A1; AU731348B2; CA2295713A1; AU8094598A; RU2199475C2; HU222915B1; TR200000101T2; NZ502501A; AUPO788697A0; IL133939A0; KR20010021816A; WO1999003747A1; BG104108A; BR9810714A

Abstract

A push-on closure (10) that can be pushed on to a container (12) and then screwed off. The container (12) has a neck (11) that is provided with a multi-start thread comprising alternating ridges (25) and grooves (26). The closure (10) includes a substantially circular top (13) and a depending skirt (14) with the skirt having a number of lugs (21) that are spaced apart circumferentially by distances corresponding to the spacing of the grooves (26) of the thread. When the closure (10) is attached to the neck (11) of the container (12), each of the lugs (21) engages with one of the recesses (27) formed in the neck (11). A ramp member (29) is also located adjacent each recess (27) so that upon relative rotation of the closure (10) at least some of the lugs (21) will bear against at least some of the ramp members (29) and be directed by the ramp members (29) into the grooves (26) in the thread to allow the closure (10) to be unscrewed from the neck (11) of the container (12).

Description

Gland

The present invention relates to a cap for a container, such as a bottle, which can be pressed onto the container and then unscrewed.

Known caps can be press-fitted onto the neck of the container and can be unscrewed from the container, so-called screw caps. This manner of coupling of the container and the cap generally depends on the use of very fine complementary threads on the container and the cap. Such a cap is placed over the neck of the container and then pressed down on the neck. When the cap is forced against the neck, the two complementary threads ride over each other. To open the cap, the cap is removed from the neck of the container by rotating the cap relative to the container so that the complementary threads engage one another.

The advantage of this cap is that it does not require complex capping fixtures, which for a typical screw cap must be rotated sufficiently relative to the neck by the capping fixture when the cap is installed to ensure that sufficient torque is applied to the cap to effect a seal. However, a difficulty with such caps is that if there is longitudinal resistance to opening the cap, the fine threads on the container and cap can peel and come together. Such resistance may be encountered, for example, when covered with a tamper evident band. The present invention is directed to providing an alternative gland construction that avoids the use of fine threads as required.

According to a first aspect, the present invention relates to a combination cap and container having a neck with an outer surface formed with a multi-start thread comprising alternating ridges and grooves, each thread groove commencing at or adjacent an upper free end of the neck and terminating in a recess formed in the neck; the cap including a generally circular top portion and a downwardly extending skirt portion, the skirt portion having an inner surface radially provided with a plurality of lugs spaced circumferentially at a spacing corresponding to the spacing of the thread grooves and axially spaced from the inner surface of the top portion, each lug engaging a recess formed in the neck portion as the cap is sealingly engaged with the container top portion when the cap is pressed downwardly onto the neck portion of the container; in the vicinity of each recess, there are provided tilting members, against which at least some of the lugs bear when the cap, which has been pressed onto the neck of the container, is relatively rotated, and from which the respective one of the thread grooves is guided, so that the cap can be unscrewed from the neck of the container.

According to a further aspect, the present invention relates to a combination of a cap and a container according to the first aspect of the invention.

According to a preferred embodiment of the invention, the multiple start thread comprises 4-8 ridges and grooves, preferably 6 ridges and grooves. Each groove preferably begins just below the tapered lip at the free end of the container neck. The tapered lip acts to facilitate outward radial deformation of the ear lobe as the cap is pressed onto and over the threaded ridge on the neck. Each thread groove preferably terminates in a recess in the neck portion formed by a generally annular recess having inclined members extending through the recess at appropriate intervals.

Preferably, the cap has a plurality of lugs on the inner surface of the skirt in the same number as the thread grooves. However, it is also possible to have fewer lugs than thread grooves, in which case a part of the thread grooves are not used. In addition, it is also possible to make the number of lugs larger than the number of thread grooves, in which case the extra lugs fold back over the thread ridges when the cap is screwed on. In either case, however, the pitch divided by the radial direction of the lug of the lead-in screw groove when screwing the cap must be equal to the circumferential pitch of the screw groove. The lugs are preferably at a level with the inner surface of the skirt.

The thread is preferably formed by a plurality of grooves having a square cross-sectional shape. Each ridge between the grooves has an upper edge with a curved cross-section. The curved portion facilitates the extrusion of the lug over the ridge when the cap is mounted on the container.

Each lug preferably has a circumferential longitudinal axis. One end of the lug is preferably chamfered and terminates at a point. The chamfer enables the lug to more easily engage the corresponding ramp when the cap is initially unscrewed from the container neck.

Preferably, near the end of each thread groove, there is an inclined member inclined so that a lug contacting the upper surface thereof can be guided upward into the bottom end of the associated thread groove. In a preferred embodiment, the upper edge of the diagonal member is located at the same spiral position as the upper edge of the threaded ridge and the upper edge of the diagonal member that are connected (also the lower edge of the adjacent upper groove). This arrangement ensures that the lug which comes into contact with the upper edge of the tilting member is smoothly guided upwardly into the associated thread groove.

It is highly desirable to provide some form of complementary seal between the container neck and the cap. In a particular embodiment of the invention the seal comprises a deformable sealing rib integral with the lid as described in us patent specification 5423444 or a variation of that described in australian patents 637706 and 74544/94. The contents of the above patent specification are hereby incorporated by reference.

For example, the sealing member may comprise an annular sealing rib projecting downwardly from beneath the top portion, the rib comprising a first portion adjacent the top portion and having an inner surface located at a radially inward portion of the skirt and separating the second portion from the top portion, and a frusto-conical second portion adjacent the first portion, the second portion extending radially inwardly and terminating in a circular free edge, the inner diameter of the first portion being related to the outer diameter of the container neck, the second portion engaging the free end of the container neck when the cap is mounted on the neck and folding over towards, preferably against, the inner surface of the rib first portion to form a seal between the container neck and the cap.

In one embodiment, the first portion of the sealing rib is formed at a portion radially inward of the skirt and forms an annular space between the first portion and the skirt. The first portion in another embodiment abuts continuously against the skirt. The first portion of the rib includes a thickened portion of the skirt proximate the top. In yet another embodiment, the sealing rib includes a generally annular area of weakness formed around an inner surface of the sealing rib generally at the junction of the first and second portions. The first portion of the rib gradually increases in thickness as it moves away from the top of the lid. The upper surface of the second portion of the sealing rib has a continuous or segmented annular ridge on or near the free circular edge. The underside of the cap top may also be provided with a segmented or continuous annular ridge located inwardly of and adjacent to the first portion of the sealing rib. The sealing rib may further include a third portion connected to the second portion at or near the rounded edge and extending substantially away from the top, the third portion being no thicker than the second portion and having a length greater than its thickness.

Alternatively, the seal may be any of the known seal structures. A sealing packing made of a compressible material such as synthetic plastic foam can be used as a flow-in gasket (flowed-in gaskete). In another embodiment, the seal is a cylindrical boss or tube extending axially from the underside of the cap top, capable of sealing engagement with the radially inner surface of the container neck. In yet another embodiment, the seal includes a cap with ribs formed on the top inner surface, and the interior of the cap is formed with a sealing membrane by rotational molding or other suitable technique.

It is desirable to have the cover with a tamper evident band that indicates whether the consumer has attempted to remove the cover from the container, whether or not successful. In a particular embodiment of the invention, the retaining band is made according to australian patent specification 668197 or us patent specification 5676269. The contents of the above patent specification are hereby incorporated by reference.

In one embodiment, the band includes a generally cylindrical body portion and a segmented rib extending inwardly of the body portion, the rib forming a lip with an inner free edge that engages under a retaining flange projecting outwardly from the container neck. The total length of the segmented ribs is preferably equal to at least 50% of the inner circumference of the belt. The inner surface of the band has a plurality of radially inward projections extending from above the free edge of the band but not beyond the free edge of the lip. In one embodiment the outer surface of the band is formed with a plurality of longitudinally extending localised areas of increased thickness separated from one another by areas of no thickness. The thickened region increases the longitudinal stiffness of the body portion, but the body portion is still able to move radially outwardly as it passes over the retaining flange on the container when the lid is mounted on the container.

In another embodiment, the rib segment on the inner surface of the belt has an upper surface generally facing generally toward the top of the cap and an underside generally facing away from the top, the upper surface of the rib segment including a first surface abutting the belt body portion and a second surface extending radially inwardly from an inner end of the first surface, the first surface sloping inwardly downwardly away from the top, the second surface having an angle of inclination generally perpendicular to the cap skirt.

Other known bands of retaining indicia may also be used. Regardless of which type of tamper-evident band is used, it is important to ensure that the force required to tear the frangible bridges connecting the band to the lower end of the skirt portion of the cap does not exceed the force applied to the cap by the action of moving the lugs upwardly along the thread grooves. Otherwise, the lug may tear or may jam against the thread ridge as the lid is rotated.

The following description of the preferred embodiments of the present invention is provided as an example of the present invention and is described with reference to the accompanying drawings. Wherein,

FIG. 1 is a cross-sectional view of a closure according to one embodiment of the present invention shown mounted on a container also according to one embodiment of the present invention;

FIG. 2 is a detailed side view of the threads on the container shown in FIG. 1;

FIG. 3 is a cross-sectional view taken along line III-III of the lid shown in FIG. 4;

FIG. 4 is a vertical cross-sectional view taken along line IV-IV of the closure shown in FIG. 3; and

fig. 5 is a sectional view taken along line V-V of the cap shown in fig. 4.

The cap 10 according to the invention shown in fig. 1 is located on the neck 11 of a container 12 according to the invention.

The cap 10 includes a circular top 13 and a cylindrical skirt 14. The band 15 is connected to the lower edge of the skirt 14 by a plurality of frangible bridges 16. The inner surface of the cap 10 is provided with a sealing rib 17 which is formed integrally with the top 13 of the cap 10 and has a generally cylindrical portion 18 spaced slightly inwardly from the skirt 14. Although the illustrated cylindrical portion 18 is located slightly inside the skirt 14, it is readily contemplated that this portion may abut or be integral with the skirt 14. The lower end of the cylindrical portion 18 is connected to a frusto-conical portion 19. As shown in fig. 4, a sharp edge 20 is provided between the first cylindrical portion 18 and the second frustoconical portion 19. When the cap 10 is applied to the container 12, the free end 23 of the neck 11 engages the truncated cone 19 and folds it back, preferably into contact with the radially inner surface of the cylindrical portion 18. The sharp edge 20 is not essential but it constitutes a line of weakness between the two

portions

18, 19 and serves to facilitate the smooth back folding of the frusto-conical portion 19 relative to the cylindrical portion 18 when the cap is fitted to the container. The folded-back frusto-conical portion 19 forms a fluid-tight seal with the radially outer surface of the neck 11 once fitted to the container.

Furthermore, although not shown in the figures, it is easily conceivable for the upper surface of the truncated-cone-shaped portion 19 to have an annular ridge near its free edge, which engages the underside of the top portion 13 when the truncated-cone-shaped portion 19 is folded back towards the cylindrical portion 18. It is also easily conceivable to have a complementary annular ridge radially inside the cylindrical portion 18, below the top portion 13.

The 6 lugs 21 are equiangularly distributed along the radially inner surface of the skirt 14 and are located at a level above the skirt 14, above the frangible bridges 16 and below the sealing rib 17. Each of the ears has a longitudinal axis lying in the plane. At the end of each lug 21, i.e. the front end when the cap 10 is unscrewed from the neck 11 (i.e. the left end of the lug 21 in the cap shown in fig. 4), the lug tapers to a point 22.

The outer surface of the neck 11 of the container 12 has an outwardly tapered portion 24 adjacent the free end 23. On the outer surface of the neck 11 below the portion 24 there are 6 alternating helical ridges 25 and grooves 26. The ridges 25 and grooves 26 comprise multi-start threads. An annular recess 27 is provided on the outer surface of the neck 11 below the threads. The annular recess 27 is located at a level around the neck 11 and has a depth equal to the depth of the groove 26. Thus, the lower end of the ridge 25 projects above the recess 27. An outer retaining flange 28 for retaining the identification band 15 of the cap 10 is looped around the underside of the annular recess 27. There are also 6 ramps 29 in the annular recess 27. The lower end of each sloping member 29 is connected to the holding flange 28, while the upper end is connected to the lower end of one of the thread ridges 25. The upper surface of the inclined member 29 is located at the same spiral position as the thread ridge 25 and the upper surface connected thereto (also the lower surface of the adjacent upper groove 26).

In use, the cap 10 is positioned over the neck 11 of the container 12 in the capping fixture. The lid 10 is then pressed vertically downwards by the clamp. The lug 21 then slides over the external tapered portion 24 and the thread ridge 25 of the neck 11 until the lug is a point below the upper edge of the annular recess 27. The lid 10 is then rotated slightly by the clamp in a clockwise direction (see fig. 1) relative to the container 12 about the longitudinal axis of the lid 10. The effect of this rotation is to disengage the lug 21 from the ramp 29 and locate it in the groove 27 and at the lower end of the corresponding thread ridge 25.

As the cap 10 is pressed onto the neck 11, the sealing rib 17 comes into contact with the free end 23 of the neck 11. The truncated-cone-shaped portion 19 is folded back by the neck 11, preferably against the inner surface of the cylindrical portion 18 of the sealing rib 17. The sealing rib 17 thus forms a seal between the cap and the container 12, in particular against the outer conical portion 24 and the free end 23 of the neck 11.

Another effect of the cap 10 being mounted on the neck 11 is that once the cap 10 is fully sealed on the neck 11, the inwardly lipped rib 30 on the inner surface of the tamper-evident band 15 is pressed over the retaining flange 28 to engage under the retaining flange 28. Thus, removal of the cap 10 from the container 12 tears only the frangible bridges 16, leaving the tamper-evident band 15 on the neck of the container 12.

The ribs 30 are formed by a series of rib segments 31 spaced apart by small spaces 32, which in the illustrated embodiment are 85% of the circumference of the belt 15. The small spaces 32 provide flexibility to the band 15 in the circumferential direction to allow the ribs 30 to pass the retaining lip 28 without creating stress that could break the frangible bridges 16.

Each rib section 31 has an upper edge towards the top 13 and a lower edge away from the top 13. The upper edge has a radially outer frusto-conical surface 33 and a radially inner annular surface 34. The annular surface 34 lies in a plane perpendicular to the longitudinal axis of the cap 10, while the truncated conical surface 33 slopes inwardly and downwardly away from the top 13. The provision of the truncated conical surface 33 facilitates moulding of the lid 10 as this prevents or at least significantly reduces the production of lids with deformed ribs 30.

When the container is to be opened, the user turns the lid in a counter-clockwise manner (see fig. 1). At this time, the lugs 21 are brought into contact with the corresponding inclined members 29 and are guided into the lower ends of the screw grooves 26. The lugs 21 and the relative upward movement of the cap 10 relative to the neck 11 bring the rib segments 31 into contact with the lower edge of the retaining flange 28. Further rotation of the cap 10 raises the cap 10, which is also on the neck 11, and finally tears the frangible bridges 16. Rotation may then continue until the cap 10 is lifted off the neck 11.

It will be apparent to those skilled in the art that various changes and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

1. A combination cap and container having an outer surface formed with a neck portion having a multi-start thread comprising alternating ridges and grooves, each thread groove commencing at or adjacent an upper free end of the neck portion and terminating in a recess formed in the neck portion; the cap including a generally circular top portion and a downwardly extending skirt portion, the skirt portion having an inner surface radially provided with a plurality of lugs spaced circumferentially at a spacing corresponding to the spacing of the thread grooves and axially spaced from the inner surface of the top portion, each lug engaging a recess formed in the neck portion as the cap is sealingly engaged with the neck portion of the container when the cap is pressed downwardly onto the neck portion of the container; in the vicinity of each recess, there are provided tilting members, against which at least some of the lugs bear when the cap, which has been pressed onto the neck of the container, is relatively rotated, and from which the respective one of the thread grooves is guided, so that the cap can be unscrewed from the neck of the container.

2. The cap and container combination of claim 1, wherein the multiple start thread comprises 4-8 ridges and grooves.

3. The cap and container combination of claim 2, wherein the multi-start thread comprises 6 ridges and grooves.

4. A combination cap and container as claimed in any preceding claim wherein each groove starts below the tapered lip of the free end of the neck of the container.

5. A combination cap and container according to any preceding claim, wherein the cap has a plurality of lugs on the inner surface of the skirt in the same number as the thread grooves.

6. A combination of a cap and a container as claimed in any one of claims 1 to 4, wherein the number of lugs of the cap is different from the number of screw-grooves.

7. A cap and container combination as claimed in claim 5 or 6, wherein the radial spacing of the lugs leading into the screw-threaded grooves when the cap is screwed on is equal to the circumferential spacing of the screw-threaded grooves.

8. A combination cap and container as claimed in any preceding claim wherein the lug is located at a level on the inner surface of the skirt.

9. A combination cap and container as claimed in any preceding claim wherein the screw-channel has a square cross-sectional shape.

10. A lid and container combination according to any preceding claim, wherein each ridge between channels has an upper edge which is curved in cross-section.

11. A combination cap and container as claimed in any preceding claim wherein each lug has a circumferential longitudinal axis.

12. A combination cap and container as claimed in any preceding claim wherein one end of the lug is chamfered.

13. The lid and container combination of claim 12 wherein an end of the ear lobe forms a point.

14. A combination cap and container as claimed in any one of the preceding claims in which the ramp has an upper edge which is located at the same helical position as the lower edge of the screw-threaded channel into which the lug is introduced.

15. A combination cap and container according to any preceding claim, wherein a complementary seal is provided between the neck of the container and the cap.

16. The lid and container combination of claim 15 wherein the seal comprises a deformable sealing rib integral with the lid and projecting downwardly from beneath the top of the lid.

17. A combination cap and container according to claim 16, wherein the rib comprises a first portion adjacent the top portion and having an inner surface and a frusto-conically shaped second portion adjacent the first portion, the inner surface being located at a radially inward portion of the skirt and separating the second portion from the top portion, the second portion extending radially inward and terminating in a circular free edge, the inner diameter of the first portion being related to the outer diameter of the neck of the container, the second portion engaging the free end of the neck of the container and folding back towards the inner surface of the first portion of the rib during mounting of the cap on the neck, thereby forming a seal between the neck of the container and the cap.

18. The lid and container combination of claim 17 wherein the second portion is folded back against the inner surface of the first portion of the sealing rib.

19. A combination cap and container according to any preceding claim, wherein the cover is provided with a tamper evident band to indicate to the consumer whether or not attempts have been made to remove the cap from the container, whether or not successful.

20. The cap and container combination of claim 19 wherein the band includes a generally cylindrical body portion and a segmented rib extending inwardly of the body portion, the rib forming a lip with an inner free edge for engaging under a retaining flange projecting outwardly from the container neck, the segmented rib having an overall length equal to at least 50% of the circumference of the band, the band having an inner surface with a plurality of radially inward projections extending above the band free edge but not beyond the inner free edge of the lip.

21. A lid and container combination according to claim 19 or 20 wherein the rib section on the inner surface of the band has an upper surface which faces generally towards the top of the lid and an underside which faces generally away from the top, the upper surface of the rib section comprising a first surface which abuts the body portion of the band and a second surface which extends radially inwardly from the inner end of the first surface, the first surface sloping inwardly and downwardly away from the top, the second surface having an angle of inclination which is generally perpendicular to the lid skirt.

22. A container for use in the combination of any preceding claim.

23. A cap for use in the combination of any preceding claim.