GB2087851A - Improvements in or relating to containers and container closures - Google Patents

Improvements in or relating to containers and container closures Download PDF

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Publication number
GB2087851A
GB2087851A GB8129492A GB8129492A GB2087851A GB 2087851 A GB2087851 A GB 2087851A GB 8129492 A GB8129492 A GB 8129492A GB 8129492 A GB8129492 A GB 8129492A GB 2087851 A GB2087851 A GB 2087851A
Authority
GB
United Kingdom
Prior art keywords
container
thread
profile
flank
closure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB8129492A
Other versions
GB2087851B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Arconic Closure Systems International UK Ltd
Original Assignee
Metal Closures Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Metal Closures Ltd filed Critical Metal Closures Ltd
Priority to GB8129492A priority Critical patent/GB2087851B/en
Publication of GB2087851A publication Critical patent/GB2087851A/en
Application granted granted Critical
Publication of GB2087851B publication Critical patent/GB2087851B/en
Expired legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D1/00Containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material, by deep-drawing operations performed on sheet material
    • B65D1/02Bottles or similar containers with necks or like restricted apertures, designed for pouring contents
    • B65D1/0223Bottles or similar containers with necks or like restricted apertures, designed for pouring contents characterised by shape
    • B65D1/023Neck construction
    • B65D1/0246Closure retaining means, e.g. beads, screw-threads
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D41/00Caps, e.g. crown caps or crown seals, i.e. members having parts arranged for engagement with the external periphery of a neck or wall defining a pouring opening or discharge aperture; Protective cap-like covers for closure members, e.g. decorative covers of metal foil or paper
    • B65D41/02Caps or cap-like covers without lines of weakness, tearing strips, tags, or like opening or removal devices
    • B65D41/04Threaded or like caps or cap-like covers secured by rotation
    • B65D41/0435Threaded or like caps or cap-like covers secured by rotation with separate sealing elements
    • B65D41/0464Threaded or like caps or cap-like covers secured by rotation with separate sealing elements the screw-thread or the like being formed by conforming the cap-skirt to the thread or the like formation on a container neck

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Ceramic Engineering (AREA)
  • Closures For Containers (AREA)

Abstract

The profile of the screw-thread on a container, e.g. a glass or plastics bottle, is asymmetrical with respect to a plane normal to the axis of the neck of the container, and has the flank 13 of the profile which faces away from the top of the container formed with a rectilinear portion which is more steeply inclined than any portion of the other flank 14 and which is inclined at an angle in the range 3 DEG to 20 DEG , preferably 15 DEG , with respect to a plane normal to the lengthwise axis of the neck. A closure is rolled in situ into conformity with the thread on the container by a thread roller having its flank inclined at angles matched to those of the flanks of the screw-thread on the container. The closure may alternatively be pre-formed, e.g. from plastics and have an internal screw-thread which has a complementary profile to that of the container, the more steeply inclined flank of the profile facing the top of the closure. <IMAGE>

Description

SPECIFICATION Improvements in or relating to containers and container closures This invention relates to containers and container closures. The invention is more particularly but not exclusively concerned with containers, such as glass and plastics bottles, intended for containing beverages under pressure and having a neck with an external screw-thread for attachment of a closure, for example a preformed plastics or metal closure or an aluminium closure intended to be rolled in situ into conformity with the screw-thread on the container neck in the known manner, and with the closures for such containers.
According to this invention there is provided a container having a neck the external surface of which is formed with a screwthread having a profile which is generally curved and the flank of which facing in a direction away from the top of the container has a portion inclined at an angle in the range 3" to 20 with respect to a plane normal to the lengthwise axis of the neck, the length of which portion constitutes a finite proportion of the length of the flank, and said portion being the most steeply inclined portion of said flank.
The invention also provides a closure comprising a top with a dependent skirt which has an internal screw-thread the profile of which is generally curved and the flank of which facing in a direction towards the top of the closure has a portion inclined at an angle in the range 3 to 20 with respect to a plane normal to the lengthwise axis of the skirt, the length of which portion constitutes a finite proportion of the length of the flank, and said portion being the most steeply inclined portion of said flank.
Said portion is preferably rectilinear.
The profile is preferably asymmetrical and said portion is the most steeply inclined portion of the profile.
It is preferred that the said angle should be in the range 3" to 15 , but some lesser advantage can be obtained when the angle is 16 , 17 , or 18 to 20 . At the lower end of the range, 5" is the minimum angle which glass-makers ordinarily use because of problems of extracting glass bottles from their moulds but the problems, even with smaller angles, are not insrumountable. Similarly, these angles may be employed with plastics bottles designed to be equipped with roll-on or pre-threaded closures.
The invention further provides a container as set forth in the second paragraph hereof and having thereon a metal closure which has been rolled by a thread roller into screwthreaded engagement with the thread on the container.
In a preferred embodiment of the invention the said flank of the profile is defined jointly by two circular arcs which respectively extend from the root and crown portions of the thread profile and by a straight line of finite length which joins and forms a common tangent to the two arcs and which constitutes the said portion of the flank, the centre of the arc which extends from the crown of the profile being nearer than the centre of the other arc to the lengthwise axis of the neck, and both of said centres being disposed between two imaginary lines parallel to the lengthwise axis of the neck of the container, or as the case may be the skirt of the closure, and respectively extending tangentially of the bottom of the thread groove and tangentially of the crown of the thread.The centre of said arc which extends from the crown of the thread profile is preferably disposed approximately mid-way between the said two imaginary lines.
One embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows the threaded neck portion of a container according to the invention, Figure 2 shows the thread profile of the container on an enlarged scale, and Figure 3 shows a sectional view of a closure applied to a container according to the invention.
Referring to the drawings, a moulded glass bottle is shown having a neck portion 10 formed with an external screw-thread 11 and a security band 1 2. The thread profile has its lower flank 1 3 extending at a steeper angle than the upper flank 1 4 and has its steepest portion 1 5 formed as a straight line which is of finite length, instead of the conventional form in which the thread profile is symmetrical about a line at right angles to the central lengthwise axis of the neck, and in which the flanks and crown of the profile are formed by smoothly connecting circular arcs.The profile of the bottom portion 1 6 of the groove is in the form of a circular arc which, on the lower flank 1 5 of the thread profile, is joined to a circular arc 1 7 extending from the crown of the thread ridge by the straight line portion 1 5 forming a common tangent to the two arcs 16, 1 7. The straight line portion 1 5 extends at an angle of 15 to a plane normal to the lengthwise axis of the neck, but may in other constructions extend at any angle in the range 5 to 15 . The profile of the upper flank 14 is formed jointly by a continuation of the arc 1 6 and by a circular arc 1 8 which is smoothly joined to arc 1 6 and which extends from arc 1 6 to the crown of the thread ridge. A straight line 1 9 parallel to the central lengthwise axis of the neck joins the arcs 1 8 and 1 7 and extends tangentially with respect to both arcs.It will be seen that the centre 1 7a of the circular arc 1 7 is disposed approximately midway between lines 20 and 21 drawn parallel to the central axis of the bottle through the crown of the thread profile and the bottom of the thread groove, and that the centre 1 6a of arc 16 also lies between the lines 20 and 21.
In use of the container, a closure 25 (see Fig. 3) in the form of a straight-sided cupshaped blank with a sealing gasket 26 in the bottom of the cup is applied to the container by the well-known method generally described in our Patent Specification No. 975739. In the present instance, a thread roller is used which has flank angles of 15 and 25 arranged respectively to deform the metal of the blank into contact with the flanks 1 3 and 14 respectively of the thread profile on the bottle.
When the downward pressure on the top of the closure is released on termination of the closure application procedure, the thread form on the closure is typically as shown in Fig. 3, i.e. the flank portions of the threads on the closure and container are in contact, but the closure is out of contact with the crown and groove-bottom portions of the thread on the container. Under the effect of the pressure within the container, the lower flank 1 3 of the thread profile in the region where its angle is 15 is heavily engaged by the closure and provides the whole or substantially whole of the force holding the closure on the container, whilst there is no pressure or only a small pressure between the closure and the upper flank 14 of the thread profile of the container.
It has been found that if in forming the thread on the closure a roller is used which has a profile matched to the profile of the new thread there is a considerable improvement in the blow-off pressure value of the closure, i.e.
the pressure within the bottle at which the closure thread gives way and deforms sufficiently to allow the closure to be blown off.
Even when the thread rollers employed are of conventional profile, e.g. having both sides inclined at 25 , there is a marked improvement in the blow-off pressure of the closure.
A surprising characteristic of the illustrated arrangement is that it does not result in a perceptible increase in the torque which it is necessary to apply to the closure to remove it from the container, allowing for the fact that there is a substantial variation in the removal torque between one conventional closure and another even when the closures are nominally identical.
The increased pressure holding power of closures applied to the present containers permits aluminium roll-on closures to be used on bottles and other containers containing liquids under greater pressure than has hitherto been practicable under normal manufacturing conditions. Also this increased holding power enables the length of thread on the container to be reduced in comparison with that of a closure on a container with a conventional thread designed to withstand a given pressure; in consequence the height of the closure of the neck of the container can be reduced, resulting in a saving of material.
As will be evident from Figs. 1 and 3, the invention is applicable to containers with or without a security band.
The containers may be made from any suitable material, for example metal, glass or plastics material.
The invention is equally applicable to preformed closures for such containers. In this case, the profile of the screw-thread will be substantially complementary to the screwthread on the container, the more steeply inclined flank of the prcfile being that facing towards the top of the closure. Such preformed closures may be made from metal or plastics materials.

Claims (14)

1. A container having a neck the external surface of which is formed with a screwthread having a profile which is generally curved and the flank of which facing in a direction away from the top of the container has a portion inclined at an angle in the range 3" to 20 with respect to a plane normal to the lengthwise axis of the neck, the length of which portion constitutes a finite proportion of the length of the flank, being the most steeply inclined portion of said flank.
2. A container as claimed in claim 1, wherein said portion is rectilinear.
3. A container as claimed in claim 1 or claim 2 wherein said angle is in the range 5" to 15 .
4. A container as claimed in any of claims 1 to 3, wherein the said flank of the profile is defined jointly by two circular arcs which respectively extend from the root and crown portions of the thread profile and by a straight line of finite length which joins and forms a common tangent to the two arcs and which constitutes the said portion of the flank, the centre of the arc which extends from the crown of the profile being nearer than the centre of the other arc to the lengthwise axis of the neck, and both of said centres being disposed between two imaginary lines parallel to the lengthwise axis of the neck and respectively extending tangentially of the bottom of the thread groove and tangentially of the crown of the thread.
5. A container as claimed in claim 4, wherein the centre of said arc which extends from the crown of the thread profile is disposed approximately mid-way between the said two imaginary lines.
6. A container as claimed in any one of claims 1 to 5, wherein the crown of the thread profile includes a rectilinear portion extending parallel to the lengthwise axis of the neck.
7. A container substantially as hereinbefore described with reference to and as illustrated in Figs. 1 and 2 of the accompanying drawings.
8. A container as claimed in any one of claims 1 to 7 and having thereon a metal closure which has been rolled by a thread roller into screw-threaded engagement with the thread on the container.
9. A metal closure which has been rolled into engagement with the screw-thread of a container as claimed in any one of claims 1 to 9 by a thread roller.
1 0. A closure comprising a top with a dependent skirt which has an internal screwthread the profile of which is generally curved and the flank of which facing in a direction towards the top of the closure has a portion inclined at an angle in the range 3" to 20 with respect to a plane normal to the lengthwise axis of the skirt, the length of which portion constitutes a finite proportion of the length of the flank, and said portion being the most steeply inclined portion of said flank.
11. A closure as claimed in claim 10, wherein said portion is rectilinear.
1 2. A closure as claimed in claim 10 or claim 11, wherein said angle is in the range 5" to 15 .
1 3. A closure as claimed in any one of claims 10 to 12, wherein the said flank of the profile is defined jointly by two circular arcs which respectively extend from the root and crown portions of the thread profile and by a straight line of finite length which joins and forms a common tangent to the two arcs and which constitutes the said portion of the flank, the centre of the arc which extends from the crown of the profile being nearer than the centre of the other arc to the lengthwise axis of the neck, and both of said centres being disposed between two imaginary lines parallel to the lengthwise axis of the skirt of the container and respectively extending tangentially of the bottom of the thread groove and tangentially of the crown of the thread.
14. A closure having a top wall with an internally pre-threaded peripheral skirt, the profile of which thread is substantially as hereinbefore described with reference to and as illustrated in Fig. 2 of the drawings, the steeper flank of the profile facing towards the top wall of the closure.
GB8129492A 1980-10-03 1981-09-30 Improvements in or relating to containers and container closures Expired GB2087851B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8129492A GB2087851B (en) 1980-10-03 1981-09-30 Improvements in or relating to containers and container closures

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8032030 1980-10-03
GB8129492A GB2087851B (en) 1980-10-03 1981-09-30 Improvements in or relating to containers and container closures

Publications (2)

Publication Number Publication Date
GB2087851A true GB2087851A (en) 1982-06-03
GB2087851B GB2087851B (en) 1984-08-15

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB8129492A Expired GB2087851B (en) 1980-10-03 1981-09-30 Improvements in or relating to containers and container closures

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8215508B2 (en) * 2007-08-21 2012-07-10 Nalge Nunc International Corporation Centrifuge bottle closure and assembly thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8215508B2 (en) * 2007-08-21 2012-07-10 Nalge Nunc International Corporation Centrifuge bottle closure and assembly thereof

Also Published As

Publication number Publication date
GB2087851B (en) 1984-08-15

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PCNP Patent ceased through non-payment of renewal fee