WO2001074683A1

WO2001074683A1 - Method for producing a closure device and closure devices produced according to the method

Info

Publication number: WO2001074683A1
Application number: PCT/SE2001/000685
Authority: WO
Inventors: Bengt Malmborg
Original assignee: Modulpac Ab
Priority date: 2000-03-31
Filing date: 2001-03-29
Publication date: 2001-10-11
Also published as: SE0001147L; SE0001147D0; AU2001242989A1

Abstract

In a method for producing from plastic a closure device comprising a first part (2), which has a cylindrical outer section with a radially projecting flange (7), and a second part (3), which has a cylindrical inner section, a blank (1') is injection-moulded, in which blank the cylindrical sections of the two parts (2, 3) are arranged in line with each other along a cylinder axis (C) and fixedly connected to each other along the outer circumference of the outer section and the inner circumference of the inner section. The blank (1') is next extracted from the mould and its constituent parts (2, 3) are brought together in the direction of the cylinder axis (C) such that the fixed connection between the parts (2, 3) is broken and the parts (2, 3) are made to assume a defined mutual position in which they are rotatable relative to each other about the cylinder axis (C). In the injection-moulding, at least one recess (8) is formed in the flange (7) of the first part (2) and at least one projection (13), corresponding to the recess (8), is formed on the second part (3), which projection (13) is arranged so as, in interaction with the recess (8), to prevent mutual relative rotation of the parts (2, 3).

Description

METHOD FOR PRODUCING A CLOSURE DEVICE AND CLOSURE DEVICES PRODUCED ACCORDING TO THE METHOD

Technical Field

The present invention relates to a method for producing from plastic a closure device comprising a first part, which has a cylindrical outer section and a top forming a circumferential flange projecting radially from the part, and a second part, which has a cylindrical inner section, the outer section of the first part fitting inside the inner section of the second part and the two parts being mutually rotatable about a common central cylinder axis, which method comprises the steps of injection-moulding a blank, m which blank the cylindrical sections of the two parts are arranged m line with each other and fixedly connected to each other along the outer circumference of said outer section and the inner circumference of said inner section, extracting the blank from the mould, breaking the fixed connection between the parts and bringing together the parts by pressing them together m the direction of said cylinder axis such that they are made to assume a defined mutual position m which they are rotatable relative to each other about said cylinder axis.

In addition, the present invention relates to a closure device, produced according to the method and intended for childproof closure of a container having a spout with an outer thread, and alternatively a closure device produced according to the method and intended for closure of a packaging container made from plastic-wrapped paper, plastic or sheet metal.

Background of the Invention

There are a large number of different closure devices which, like the devices according to the invention, consist of two interacting parts having cylindrical sections which enable mutual rotation of the parts about a common cylinder ax s. Such devices are characterised m that their two constituent parts are individually produced m separate moulds, which are employed one after the other m one and the same m ection-mouldmg machine or simultaneously m two separate machines. They are also characterised m that their constituent parts must then be assembled, which is most often done using an assembly machine. Since one of the working operations which are required m the assembly comprises the mutual alignment of the two parts, and sometimes also the mutual rotation of the parts, it will be appreciated that such an assembly machine is relatively complex and hence expensive, that recurrent work stoppages are difficult to prevent due to the mutual alignment of the parts not always being successful, and that the assembly machine can represent a bottleneck m the production since its work cycle does not always correspond to the work cycle of the injection- moulding machine. Against this background, it will be appreciated that there is a need for a more effective and secure method for producing from plastic closure devices of the type stated m the introduction.

A very effective method for producing the closure devices m question is described m patent specification DE-A-25 48 349. The solution described m this specification and referred to above m the introduction has the drawback, however, that, m order to prevent mutual relative rotation of the parts, it has members which can neither be produced by means of moulds without a number of moving jaws nor can be used without a so-called pincers grip, which creates difficulties for rheumatics, for example .

Object of the Invention

The object of the invention is to improve the previously known method and the previously known solutions according to the introduction m such a way that the drawbacks associated with the known solutions are eliminated.

Summary of the Invention

According to the invention, this is achieved by a method according to the introduction through the steps of, m the injection-moulding, forming m the flange of the first part at least one recess, and, m the m ec- tion-mouldmg, forming on the second part at least one projection corresponding to said recess, which projection is arranged so as, m interaction with said recess, to prevent mutual relative rotation of the parts.

Owing to the method according to the invention, it consequently becomes possible to produce simultaneously, m a known manner, both parts of a closure device m one and the same mould and mjection-mouldmg machine, which implies major logistic advantages. In addition, owing to the method according to the invention, it becomes pos- sible to assemble, m a known manner, both parts of a closure device by a simple pressing-together operation without the need for prior precise alignment of the parts and without the need for these, when they have threads which are to interact with each other, to be mutually rotated. In addition, owing to the method according to the invention, it also becomes possible to use simpler moulds than previously, which means that the method according to the invention considerably simplifies the production of closure devices of the type m question and that it additionally provides good prospects for an increased production rate due to very few production stoppages as a result of efficient machine use.

A closure device as stated m the introduction, produced according to the method and intended for child- proof closure of a container having a spout with an outer thread, is characterised according to the present invention m that the first of the two parts is an inner part, which has an inner thread corresponding to the outer thread of the spout and a top intended for sealing contact against the opening of the spout, which top has external ramp members which, viewed m the direction of unscrewing of the closure device, at the front have a ramp surface which ascends m accordance with the inner thread and at the back have a substantially vertical wall surface, and m that the second of the two parts is a tubular outer part, snap- fastened onto the outside of the inner part, which outer part is rotatable about and, to a limited extent, is displaceable along said cylinder axis and has internal ramp members which are arranged to interact with the ramp members of the inner part such that unscrewing of the closure device is only possible if the outer part is simultaneously rotated and subjected to load such that the internal ramp members are detained m the external ramp members, the ramp members of the outer part being internally formed on an inward-directed, circumferential flange which is situated at the end of the outer part directly opposite the previous connecting point with the inner part .

It will be appreciated that a closure device which is thus configured acts like any other known childproof closure device which also consists of two mutually rotat- able parts which can be made to interact with each other by means of ramp members integrated therein and which is intended for childproof sealing of bottles or the like having health-threatening contents, the advantage of the solution according to the invention being that the chosen positioning of the ramp members facilitates the mjection-mouldmg, which hence can be realised by means of a mould consisting only of a top and a bottom mould, the outer part, order to facilitate extraction from the mould following the mjection-mouldmg, preferably having slots which extend radially through the flange and from this a distance along said cylinder axis through the wall of the outer part . In another closure device as stated the introduction, produced according to the method and intended for closure of a packaging container made from plastic- wrapped paper, plastic or sheet metal, the first of the two parts is a tubular, outer part, which has an inner thread and, for connection to the packaging container, an outward-directed, circumferential flange at its one end and an opening at its other end, and the second part is a cup-shaped, inner part, which has an outer thread, corresponding to said inner thread, and an outward- directed, circumferential flange extension of the cup bottom, the inner, cup-shaped part being unscrewable from the outer, tubular part, whose opening it, m the screwed- tight state, seals by means of its flange, the tubular, outer part having at least one breakp projecting from its other end along said cylinder axis, which breakpm, following pressmg-together of the outer and the inner part along said cylinder axis, extends through a corresponding hole m the outward-directed flange of the cup-shaped, inner part, said pm being arranged to be broken off when the inner part is unscrewed from the outer part .

A closure device of this kind certainly has great similarities with known closure devices for, for example, juice packagmgs, but since the known devices are not produced by the method according to the invention, they do not have the rupture line which is formed during the assembly m accordance with the method according to the invention and nor do they have the breakpm configured according to the invention. It will be appreciated that this at least one pm, which serves as a seal indication, is easy to produce by the mould being divided m a plane extending diametrically across the closure device and parallel with the longitudinal axis of the breakpm. Preferably, moreover, the tubular, outer part has on the outside of its cup bottom gripping flanges, which extend like spokes and between which protected areas are present for the breakpms . The breakpms are thereby effectively protected from accidental breakage and a very gπp-friendly and hence easy-to-use closure device is obtained .

Brief Description of the Drawings

The invention will be described greater detail below with reference to the accompanying drawings, m which Fig. 1, m section from the side, shows a closure device according to a first embodiment of the invention; Fig. 2, m section and a perspective view obliquely from above, shows a blank for production of the closure device according to the first embodiment; Fig. 3 shows the blank m a perspective view obliquely from above;

Fig. 4, from the side and partially m section, shows a closure device according to a second embodiment of the invention; Fig. 5 shows the closure device according to the second embodiment m a perspective view obliquely from above ; and

Fig. 6, m the same perspective view, shows a blank for production of the closure device according to the second embodiment.

Description of two Closure Devices and of the Method by which they are produced

The closure device 1 m Fig. 3 is made of plastic and is intended for childproof sealing of bottles which are of known type and are not therefore shown. It consists of a first, inner cylinder part 2 and a second, outer cylinder part 3.

The first of these parts, the part 2, has an inner thread 4, for interaction with a corresponding outer thread on the bottle, and a top 5, from which an annular sealing flange 6 of wedge-shaped cross-section projects downward for interaction with an opening section of the bottle. In addition, the first part 2 has on a level with the top 5 a radially projecting annular flange 7, which has a number of interruptions m the form of notches 8 (see Figs 2 and 3) . The notches 8 are outwardly and upwardly open and, viewed in the direction of unscrewing R of the thread, have at their rear edge a vertical wall 9 and at their front edge an oblique wall 10, which ascends m accordance with the thread 4, even though substantially more steeply than the latter.

The second of the parts, the part 3, has on its inside, for snap-fastening behind (or according to Fig. 1 beneath) the annular flange 7 of the first part 2, an internal annular shoulder 11, which has a triangu- lar cross-section having a first radially aligned cathe- tus , a second cathetus which is parallel with a longitudinal or cylinder axis C, and a downward- facing hypotenuse. In addition, the second part 3 has an mward- directed, upper annular flange 12, which on its bottom side has projections 13, which are intended to interact with the notches 8 of the first part 2 and are shaped m complementary configuration with these. The second part 3 also has two diametrically opposing slots 14, which extend radially through the upper annular flange 12 and a distance down the wall of the part 3. The purpose of the slots 14 is to enable the second part 3 to be extracted from the mould when it is injected m a mould having fixed sections which ut m beneath the upper annular flange 12. Finally, the second part 3 has on its outside a plu- rality of ribs 15, which lie parallel with the cylinder axis C and are intended to facilitate unscrewing and screwmg-on of the closure device 1.

In the production of the closure device 1, a blank 1 ' , which is shown in Figs 2 and 3 and which comprises the two parts 2, 3, is first injected m a mould (not shown) consisting of two mould halves which define a parting line D at the vertical level of the top 5 of the first part 2. In this parting line D, the two parts 2, 3 of the blank 1' are joined together along the outer circumference of the inner part 2 and the inner circumference of the outer part 3 by means of a fixed connection 16 m the form of a thin plastics film. After the injection-moulded blank 1 ' has been extracted from the mould, it is placed m a press (not shown) , which, through pressmg-together of the blank 1' m the direction of the cylinder axis C, causes the fixed connection 16 between the parts 2, 3 to be broken and the annular shoulder 11 of the second part 3 to snap m place behind the annular flange 7 of the first part 2 so that a finished closure device 1 according to Fig. 1 is obtained.

The closure device 21 in Figs 4-6 is also made of plastic and is intended for sealing of packaging containers made from plastic-wrapped paper, which containers are of known type and are therefore not shown. The device consists of a first, outer cylinder part 22 and a second, inner cylinder part 23. The first of these parts, the part 22, is tubular and has an inner thread 24 and, for connection to the packaging container, an outward-directed, circumferential flange 25 at its one end. At its other end, it has an opening 26 through which the contents of the container can be poured. The second part, the part 23, is cup- shaped and has an outer thread 27, corresponding to the inner thread 24, and an outward-directed, circumferential flange 28 in extension of the cup bottom 29. The inner, cup- shaped part 23 can be unscrewed from the outer, tubu- lar part 22 about a cylinder axis C through the two parts

22, 23 and is intended, in the screwed-tight state, to seal said opening by means of its flange 28, a bevelled annular surface 30 expediently being present beneath this flange to compensate for differences m diameter of the opening 26, which can also have a bevelled wall section. The tubular, outer part 22 has breakpins 31 extending from its other end parallel with said cylinder axis C, which, after the outer and the inner part 22, 23 have been pressed together along said cylinder axis C, extend through corresponding holes 32 m the outward-directed flange 28 of the cup-shaped, inner part 23. The pms 31 are arranged to be broken off as the inner part 23 is unscrewed from the outer part 22 m order thereby to indicate that the packaging container is broken.

Finally, the tubular, outer part 22 has on the outside of its cup bottom 29 gripping flanges 33, which extend like spokes and between which protected areas 34 are present for the breakpms 31. The gripping flanges 33 facilitate opening and closing of the closure device and additionally offer sound protection to the breakpms 31 against accidental breakmg-off . In the production of the closure device 21, a blank 21', which is shown m Fig. 6 and comprises the two parts 22, 23, is first injected m a mould (not shown) consisting of two mould halves and two cores . The mould halves define a parting line D through the breakpms 31 and the cylinder axis C. The cores are inserted into the mould halves along the cylinder axis C, on the one hand from above for forming of the gripping flanges 33 and, on the other hand, from below for forming of the interior of the two parts 22, 23, inclusive of the inner thread 24 of the outer part, which is a so-called inversion thread, and a connection 35 between the outer and the inner part 22, 23 the form of a thin plastics film. After the injection- moulded blank 21' has been extracted from the mould, it is placed a press (not shown) , which, through press- mg-together of the blank 21' m the direction of the cylinder axis C, causes the fixed connection 35 between the parts to be broken and the threads 24, 27 of the two parts to engage with each other such that a finished closure device 21 according to Figs 4 and 5 is obtained. It will be appreciated that the invention can be varied m different ways withm the scope of the claims and that especially the latter embodiment of the closure device, with minor modifications, can also be used for other containers. Thus it is conceivable to fit it, for example, to a tube. The device is then expediently configured like the blank shown m Fig. 6, though possibly having a differently configured flange.

Claims

1. A method for producing from plastic a closure device (1; 21) comprising a first part (2; 22) , which has a cylindrical outer section and a top (5; 29) forming a circumferential flange (7; 28) projecting radially from the part (2; 22) , and a second part (3; 23) , which has a cylindrical inner section, the outer section of the first part (2; 22) fitting inside the inner section of the second part (3; 23) and the two parts being mutually rotatable about a common central cylinder axis (C) , which method comprises the steps of mjection-mouldmg a blank (I¹; 21') , m which blank the cylindrical sections of the two parts (2, 3; 22, 23) are arranged m line with each other and fixedly connected to each other (at 16; 35) along the outer circumference of said outer section and the inner circumference of said inner section, extracting the blank (1'; 21') from the mould, breaking the fixed connection (16; 35) between the parts (2, 3; 22, 23) and bringing together the parts (2, 3; 22, 23) by pressing them together m the direction of said cylinder axis (C) such that they are made to assume a defined mutual position m which they are rotatable relative to each other about said cylinder axis (C) , c h a r a c t e r i s e d by the steps of, m the mjection-mouldmg, forming m the flange (7; 28) of the first part (2; 22) at least one recess (8; 32), and, m the mjection-mouldmg, forming on the second part (3; 23) at least one projection (13; 31) corresponding to said recess (8; 32), which projection is arranged so as, m interaction with said recess (8; 32), to prevent mutual relative rotation of the parts (2, 3; 22, 23).

2. A closure device produced according to the method m claim 1 and intended for childproof closure of a container having a spout with an outer thread, c h a r a c t e r i s e d m that the first of the two parts is an inner part (2) , which has an inner thread (4) corresponding to the outer thread of the spout and a top (5) intended for sealing contact against the opening of the spout, which top has external ramp members (8) which, viewed m the direction of unscrewing (R) of the closure device, at the front have a ramp surface (10) which ascends m accordance with the inner thread (4) and at the back have a substantially vertical wall surface (10), and that the second of the two parts is a tubular outer part (3) , snap- fastened onto the outside of the inner part (2) , which outer part is rotatable about and, to a limited extent, is displaceable along said cylinder axis (C) and has internal ramp members (13) which are arranged to interact with the ramp members of the inner part (8) such that unscrewing of the closure device is only possible if the outer part (3) is simultaneously rotated and subjected to load such that the internal ramp members (13) are detained the external ramp members (8), the ramp members (13) of the outer part (3) being internally formed on an mward-directed, circumferential flange

(12) which is situated at the end of the outer part (3) directly opposite the previous connecting point (16) with the inner part (2) .

3. A device according to claim 2, c h a r a c - t e r i s e d m that the outer part (3) , m order to facilitate extraction from the mould following the jection-mouldmg, has slots (14) which extend radially through the flange (12) and from this a distance along said cylinder axis (C) through the wall of the outer part (3) .

4. A closure device produced according to the method m claim 1 and intended for closure of a packaging container made from plastic-wrapped paper, plastic or sheet metal, c h a r a c t e r i s e d m that the first of the two parts is a tubular, outer part (22) , which has an inner thread (24) and, for connection to the packaging container, an outward-directed, circumferential flange (25) at its one end and an opening (26) at its other end, and that the second part is a cup-shaped, inner part (23) , which has an outer thread (27) , corresponding to said inner thread (24), and an outward-directed, cir- cumferential flange (28) m extension of the cup bottom (29), the inner, cup-shaped part (23) being unscrewable from the outer, tubular part (22), whose opening (26) it, n the screwed-tight state, seals by means of its flange (28), the tubular, outer part (22) having at least one breakpm (31) projecting from its other end along said cylinder axis (C) , which breakpm, following pressmg- together of the outer and the inner part (22, 23) along said cylinder axis (C) , extends through a corresponding hole (32) m the outward-directed flange (28) of the cup- shaped, inner part (23) , said pm (31) being arranged to be broken off when the inner part (23) is unscrewed from the outer part (22) .

5. A device according to claim 4, c h a r a c t e r i s e d m that the tubular, outer part (22) has on the outside of its cup bottom (29) gripping flanges

(33), which extend like spokes and between which protected areas (34) are present for said breakpm (31) .