GB2201936A

GB2201936A - Thermoplastics blow-moulded container

Info

Publication number: GB2201936A
Application number: GB08803572A
Authority: GB
Inventors: Pierre Pfeiffer; Benoit Cheval; Paul Sigwalt
Original assignee: Sotralentz SA
Current assignee: Sotralentz SA
Priority date: 1987-03-11
Filing date: 1988-02-16
Publication date: 1988-09-14
Anticipated expiration: 2008-02-16
Also published as: FR2612152A1; DE3707724A1; DE8717837U1; GB2201936B; FR2612152B1; GB8803572D0

Abstract

A container made from a synthetic thermoplastic material by blowing a parison in a mould which is split into two halves along a parting line, has a single-piece body comprising a body wall (2) and endportions (3a, 3b) and optionally roller hoops (4a, 4b). One endportion (3a) has two diametrically opposed bungholes (5) on the mould parting line (1), disposed at a prescribed bunghole distance from the body wall or associated roller hoop (4a). The endportion (3a) has remote from the mould parting line, an additional bunghole (8), blown in during the blow moulding process, to facilitate complete-emptying and which has a distance from the associated roller hoop (4a) smaller than, preferably half or less, the aforementioned bunghole distance. The complete-emptying bunghole consists of an outwardly projecting collar on which is welded a nipple 11 with a sleeve-piece 10 made from synthetic thermoplastic material. The additional bunghole is preferably disposed in the same endportion as the other two bungholes. <IMAGE>

Description

THERMOPLASTICS BLOW-MOULDED CONTAINER This invention relates to a container made from a synthetic thermoplastic material by blowing a parison in a mould which is split into two halves along a parting line, and having a single-piece body comprising a jacket and endportions, and which container may have roller hoops moulded in the junction areas between the jacket and the endportions, in which at least one of the endportions has two diametrically opposed bungholes with closure means on the mould parting line, disposed at a prescribed bunghole distance from the jacket and/or the associated roller hoop.

The invention further relates to a process for the production of such containers.

When roller hoops are provided, they usually have an L-shaped cross-section. The term bunghole usually denotes the set of components forming the bunghole. The closure means are usually screw-on caps. It is obvious that the bungholes are disposed in peripheral endpiece recesses.

In a known container of this type, the bungholes are disposed in the area of the parting line in the longitudinally split mould, because in this case the formation of bungholes by blowing is particularly simple.

The shape and stability requirements in the junction areas between the jacket and the endpieces and/or around the roller hoops make it necessary to provide a relatiavely substantial bunghole distance. In the case of a container having roller hoops, the bunghole distance should be two or three times the bunghole diameter. Consequently, a step of substantial height in radial section must be provided between the bunghole and the jacket. Consequently, it is impossible to empty the container completely by merely tipping and draining it through one of the bungholes, while the other allows the entry of air into the container interior.

An object of the invention is to provide a container of the type initially described with which complete emptying is possible without difficulty.

According to the present invention, at least one of the endpieces has, remote from the mould parting line, an additional bunghole for facilitating complete emptying, which has a distance from the jacket and/or the associated roller hoop smaller than the aforementioned bunghole distance, the additional bunghole consists of an outwardly projecting collar moulded on that endportion, on which is secured a nipple with a sleeve-piece made from synthetic thermoplastic material, and the sleeve-piece and the collar are welded together.

Conveniently, the additional or "complete emptying bunghole is disposed in the endportion having the other two bungholes, in an area remote from the connecting line between the other two bungholes. The additional bunghole distance can normally be at least halved compared with the aforementioned bunghole distance. However, the preferably arrangement is such that the outer extremity of the additional bunghole is flush with the jacket, or stepped from it at a distance no greater than the jacket wall thickness.

The invention is based on the realisation that a container meeting all requirements in respect of shape and stability can be readily provided with a third bunghole flush with the jacket or only stepped slightly from the jacket, without detriment to the shape and stability standards.

Complete emptying through the additional bunghole causes no problemsv It is particularly advantageous that the additional bunghole can be formed by particularly simple means. In this respect, another object of the invention is to provide a process for the production of a container designed as described in the first aspect of the invention, based on the known process in which a thermoplasticised parison of some suitable synthetic material is inserted into a mould split into two halves along a parting line, and the tube is inflated within the mould into a single-piece blowmoulded container having a jacket and endportions formed simultaneously, with mutually opposite bungholes formed on the mould parting line in at least one of the endportions.

According to the process aspect of the invention, during the blow-moulding operation a cylindrical protuberance is blown in at least one endportion, remotely from the mould parting line and alongside the jacket, the cap of the protuberance is removed when the container has been ejected and sufficiently cooled, leaving a bunghole collar, and a nipple with sleeve-piece pre-formed by injection moulding for example is welded on to the bunghole collar. The bunghole nipple and its sleeve-piece must obviously be made from a synthetic thermoplastic material. The process in accordance with the invention can be carried out without difficulty in the existing moulds for the production of known containers, i.e. moulds split into two halves along a parting line, by adapting them to produce the containers of the invention.

Moreover, it is particularly sdvantageouQ that i variety Of bunghole nipples can be set up on the bunghole collar of the invention, including nipples differing in diameter or threading for the closure means on the additional or wcomplete-emptying" bunghole.

An embodiment of the invention will now be described, purely by way of example, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through a container in accordance with the invention, taken in the plane of the usual diametrically opposed bungholes; Figure 2 is a half-section taken on the line A-A of Figure 1, through the additional bunghole; Figure 3 is a plan view of the container of Figures 1 and 2; Figure 4 shows the area B of Figure 1, on a larger scale; Figure 5 shows the area C of Figure 2, also on a larger scale; Figure 6 shows the same area as Figure 5 as initially formed; and Figure 7 shows the same area as Figure 6 after a further stage in the production process.

The container shown in the drawings has been made by blowing a parison in a mould (not shown) split into two halves along a parting line 1 (see Figure 3). It is made from a synthetic thermoplastic material.

The container has a single-piece body comprising a jacket 2 and endportions 3a, 3b. The container shown also has roller hoops 4a, 4b moulded in the junction areas between the jacket 2 and the endportions 3a, 3b, which roller hoops have an L-shaped cross-section. The uppermost endportion 3a has two diametrically opposed bungholes 5 with closure means 6 disposed on the mould parting line 1, at a prescribed bunghole distance SA from the associated roller hoop 4a (and accordingly slightly less from the jacket 2). The bungholes 5 are disposed in peripheral recesses 7. The endportion 3a has an additional "complete-emptyingw bunghole 8, disposed remotely from the mould parting line 1 (as can be seen in Figure 3).The said bunghole has a bunghole distance VA from the roller hoop 4a (and accordingly slightly less from the jacket 2) which is appreciably less than half the original bunghole distance SA. The "complete-emptying" bunghole 8 consists, as shown more particularly in Figure 5, of an outwardly projecting collar 9 moulded on the one endportion 3a, on which is secured, as by welding, a nipple 11 with a sleeve-piece 1~ made from synthetic thermoplastic material.

Figures 5 to 7 show that the additional bunghole distance VA is minimised. The outer extremity of the "complete-emptying" bunghole 8 is stepped at 12 from the jacket 2 by a distance no greater than the wall thickness g of the jacket. Thus, complete emptying through the bunghole 8 can be effected by laying the container down and allowing air to enter its interior through at least one of the other bungholes 5.

The process of the invention is characterised in that during the blowing operation a cylindrical protuberance 13 is blown in the endportion 3a, remotely from the mould parting line 1 and alongside the jacket 2. This is shown in Figure 6. In the next stage of the process, after the container has been ejected and sufficiently cooled, the cap of the proturberance 13 is removed, to leave the bunghole -collar 9, as can be seen in Figure 7, ready for welding thereto the nipple 11 and sleeve-piece 18.

Claims

CLAIMS CLAIMS

1. A container made from a synthetic thermoplastic material by blowing a parison in a mould which is split into two halves along a parting line, and having a single-piece body comprising a jacket and endportions, and optionally roller hoops moulded in the junction areas between the jacket and the endportions, in which at least one of the endportions has two diametrically opposed bungholes with closure means on the mould parting line, disposed at a prescribed bunghole distance from the jacket and/or the associated roller hoop, at least one of the endportions having, remote from the mould parting line, an additional bunghole for facilitating complete-emptying which has a distance from the jacket and/or the associated roller hoop smaller than the aforementioned bunghole distance, the additional bunghole consisting of an outwardly proejcting collar moulded on that end portion, on which is secured a nipple with a sleeve-piece made from synthetic thermoplastic material, and that the sleeve-piece and the collar being welded together.

2. A container as in Claim 1, wherein the additional bunghole is disposed in the endportion having the other two bungholes, in an area remote from the connecting line between the other two bungholes.

3. A container as in either of Claims 1 and 2, wherein the additional bunghole distance is a half or less than half of the aforementioned bunghole distance.

4. A container as in any one of Claims 1 to 3, wherein the outer extremity of the additional bunghole is flush with the jacket, or stepped from it by a distance no greater than the wall thickness of the jacket.

5. A process of the production of a container as in any one of Claims 1 to 4, in which a thermoplasticised parison of some suitable synthetic material is inserted into a mould split into two halves along a parting line, and the tube is inflated within the mould into a single-piece container having a jacket and endportions formed simulataneously, with mutually opposite bungholes are formed on the mould parting line in at least one of the endportions, and during the blowing process a cylindrical protuberance is blown in at least one endportion, remotely from the mould parting line and alongside the jacket, the cap of the protuberance being removed when the container has been ejected and sufficiently cooled, leaving a bunghole collar, and a preformed nipple with sleeve-piece are welded on to the bunghole collar.

6. A container substantially as hereinbefore described with reference to the accompanying drawings.

7. A process for the production of a container and substantially as hereinbefore described with reference to the accompanying drawings.