METHOD FOR PRODUCING A CLOSURE DEVICE AND CLOSURE DEVICES PRODUCED ACCORDING TO THE METHOD Technical Field The present invention relates to a method for pro- ducing 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 cylindri- cal 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, in which blank the cylin- drical sections of the two parts are arranged in 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 in the direction of said cylinder axis such that they are made to assume a defined mutual position in which they are rotatable relative to each other about said cylinder axis.

In addition, the present invention relates to a clo- sure device, produced according to the method and intend- ed 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 inven- tion, consist of two interacting parts having cylindrical

sections which enable mutual rotation of the parts about a common cylinder axis. Such devices are characterised in that their two constituent parts are individually produc- ed in separate moulds, which are employed one after the other in one and the same injection-moulding machine or simultaneously in two separate machines. They are also characterised in 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 in 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 assem- bly 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 in 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 in the introduction.

A very effective method for producing the closure devices in question is described in patent specification DE-A-25 48 349. The solution described in this specifi- cation and referred to above in the introduction has the drawback, however, that, in order to prevent mutual relative rotation of the parts, it has members which can neither be produced by means of moulds without a num- ber 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 pre- viously known method and the previously known solutions

according to the introduction in such a way that the drawbacks associated with the known solutions are elimi- nated.

Summary of the Invention According to the invention, this is achieved by a method according to the introduction through the steps of, in the injection-moulding, forming in the flange of the first part at least one recess, and, in the injec- tion-moulding, forming on the second part at least one projection corresponding to said recess, which projection is arranged so as, in 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, in a known manner, both parts of a closure device in one and the same mould and injection-moulding machine, which implies major logistic advantages. In addition, owing to the method according to the invention, it becomes pos- sible to assemble, in 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 in 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 in 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 inven- tion in 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 con- tact against the opening of the spout, which top has external ramp members which, viewed in the direction of unscrewing of the closure device, at the front have a ramp surface which ascends in accordance with the inner thread and at the back have a substantially vertical wall surface, and in 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 in the external ramp members, the ramp members of the outer part being internally formed on an inward-directed, cir- cumferential 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 injec- tion-moulding, which hence can be realised by means of a mould consisting only of a top and a bottom mould, the outer part, in order to facilitate extraction from the mould following the injection-moulding, 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 in the intro- duction, 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 in extension of the cup bottom, the inner, cup-shaped part being unscrewable from the outer, tubular part, whose opening it, in the screwed-tight state, seals by means of its flange, the tubular, outer part having at least one breakpin pro- jecting from its other end along said cylinder axis, which breakpin, following pressing-together of the outer and the inner part along said cylinder axis, extends through a corresponding hole in the outward-directed flange of the cup-shaped, inner part, said pin being arranged to be broken off when the inner part is unscrew- ed from the outer part.

A closure device of this kind certainly has great similarities with known closure devices for, for example, juice packagings, 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 in accordance with the method according to the invention and nor do they have the breakpin configured according to the invention. It will be appreciated that this at least one pin, which serves as a seal indication, is easy to produce by the mould being divided in a plane extending diametrically across the closure device and parallel with the longitudinal axis of the breakpin.

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 breakpins. The breakpins are thereby effectively protected from accidental breakage and a very grip-friendly and hence easy-to-use closure device is obtained.

Brief Description of the Drawings The invention will be described in greater detail below with reference to the accompanying drawings, in which Fig. 1, in section from the side, shows a closure device according to a first embodiment of the invention; Fig. 2, in 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 in a perspective view obliquely from above; Fig. 4, from the side and partially in section, shows a closure device according to a second embodiment of the invention; Fig. 5 shows the closure device according to the second embodiment in a perspective view obliquely from above; and Fig. 6, in 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 in 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 con- sists 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 in 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 in 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 longi- tudinal or cylinder axis C, and a downward-facing hypo- tenuse. In addition, the second part 3 has an inward- 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 in 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 in a mould having fix- ed sections which jut in 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 screwing-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 in 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 cir- cumference of the inner part 2 and the inner circumfe- rence of the outer part 3 by means of a fixed connection 16 in the form of a thin plastics film. After the injec- tion-moulded blank 1'has been extracted from the mould, it is placed in a press (not shown), which, through pressing-together of the blank 1'in 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 in 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 con- tainers 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 in diameter of the opening 26, which can also have a bevelled wall section.

The tubular, outer part 22 has breakpins 31 extend- ing 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 in the outward-directed flange 28 of the cup-shaped, inner part 23. The pins 31 are arranged to be broken off as the inner part 23 is unscrewed from the outer part 22 in order thereby to indicate that the packaging container is broken.

Finally, the tubular, outer part 22 has on the out- side of its cup bottom 29 gripping flanges 33, which extend like spokes and between which protected areas 34 are present for the breakpins 31. The gripping flanges 33 facilitate opening and closing of the closure device and additionally offer sound protection to the breakpins 31 against accidental breaking-off.

In the production of the closure device 21, a blank 21', which is shown in Fig. 6 and comprises the two parts 22,23, is first injected in a mould (not shown) consist- ing of two mould halves and two cores. The mould halves define a parting line D through the breakpins 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 in the form of a thin plastics film. After the injection- moulded blank 21'has been extracted from the mould, it is placed in a press (not shown), which, through press- ing-together of the blank 21'in 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 in different ways within 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 con- figured like the blank shown in Fig. 6, though possibly having a differently configured flange.