EP2288556B1

EP2288556B1 - A container for extrudable material

Info

Publication number: EP2288556B1
Application number: EP09746120.6A
Authority: EP
Inventors: Paul Evans
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-05-16
Filing date: 2009-05-15
Publication date: 2013-11-13
Anticipated expiration: 2029-05-15
Also published as: EP2288556A1; GB2455372A8; WO2009138803A1; GB0808946D0; GB2455372A; GB2455372B; ES2436715T3

Description

This invention relates to a container for extrudable material comprising a flexible bag, often referred to as a "chub" containing the extrudable material.
Chubs are conventionally manufactured from flexible sheet synthetic plastics material formed, during the manufacturing process, into a continuous tube defining a longitudinal cavity filled with the extrudable material. For some applications a tuck is formed in the tube so as to define a second longitudinal cavity extending alongside the first, this second cavity being filled with a second extrudable material. On dispensation from the chub, these materials react, normally to produce a hardening effect, though in principle other chemical effects such as foaming would be possible. After filling, pairs of wire pieces are crimped around the tube at regular intervals and the tube is then cut between the crimps of each pair to form individual chubs each sealed at opposite ends.
In one known technique, described in patent specification EP0754633 , each chub is then placed in a cylindrical injection moulded cartridge so that one crimped end of the chub passes through an outlet port of the cartridge. A plunger or piston slides into the other end of the cartridge. Immediately before use, the user cuts through the chub, just inwardly of the crimp, to allow its contents to be released. The user then screws a nozzle or mixer onto the cartridge and uses a conventional extrusion gun to drive the plunger further into the cylinder, compressing the chub and forcing its contents out of the outlet port and nozzle. Where a twin compartment chub is employed as described above, it is normal for the nozzle to contain an insert or mixer element designed to assist in the mixing of the components.
Users find it inconvenient and time consuming to perform the process of cutting through the chub each time a new cartridge is loaded into the gun. The problem cannot satisfactorily be overcome by performing the cutting process during manufacture because the integrity of the chub is relied upon to isolate its contents, which may be toxic, from the environment. In the case of a two-part chub there is the additional problem that the separate components would not be isolated from each other.
Patent specification EP0754633 , which forms the basis for the preambles of appended claims 1 and 4, recognises the above problem and attempts mitigate it in the arrangement shown in Fig 3 by providing a cutting mechanism that is operated immediately before use of each cartridge. However this does not solve the problem that the user has to perform a cutting operation
Patent specification WO2007/026169 describes a proposal to overcome the problem by using a wire crimp at one end of the chub that is sufficiently weak to be forced off the chub by the pressure created by the extrusion gun. However, this necessitates the use of a non-standard chub manufacturing process. Furthermore, the requirement to weaken the chub sufficiently to allow it to break open under the pressure applied by the extrusion gun necessarily compromises the chub's effectiveness in safely containing its contents before use.
According to a first aspect of the invention there is provided a method of preparing a container of extrudable material starting from means defining an outlet for the material, closure means for the outlet and a flexible bag that contains the extrudable material and has a discharge end closed by a crimp; the method comprising the steps of

a. passing a discharge end and the crimp through the outlet, and characterised by
b. after step a, interfitting the closure means and the outlet, whereby the interfitting action of the closure means and the outlet serves to hold the discharge end closed.

According to a second aspect of the invention there is provided container for extrudable material comprising: a. means defining an outlet for the material;

b. a closure means for the outlet; and
c. a flexible bag containing the extrudable material and having a discharge end which extends through the outlet being closed, the portion of the discharge end extending outside the outlet being closed by a crimp, characterized in that the discharge end of the flexible bag is closed and held closed by an interfit action between the closure means and the outlet.

In a preferred construction a removable release member screws on to the outlet and is used to hold the plug firmly in position until ready for use. The release member and the plug are formed with detent means designed so that, when the release member is screwed into position during manufacture, the release member and the plug or other closure means become locked together in an axial direction (whilst still allowing relative rotation about the axis). Consequently, when the release member is removed by the user, the closure means is automatically removed with it. The user then needs only to fit the nozzle onto the outlet and to place the cartridge in a suitable gun before use. The "detent means" can easily be formed by a resiliently flexible flange on the release member designed to snap over a corresponding shoulder on the outlet port (or vice-versa).
Two embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which:

Fig. 1 shows an axial cross-section through a cartridge constructed in accordance with the invention, before fitting of a closure cap, shown separately;
Fig 2 is similar to Fig 1 but showing the cap fitted onto the cartridge;
Fig 3 shows a nozzle for fitting onto the cartridge in place of the cap after the latter is removed;
Fig 4 illustrates a side elevation of a second embodiment of the invention;
Fig 5 shows an axial cross-section through an alternative plug assembly in place of the plug shown on Figs 1 and 2;
Fig 6 the plug of Fig 5 as viewed in an axial direction; and
Fig 7 is a view similar to Fig 5 but showing a locking ring in place of the plug shown on Figs 1 and 2.

Referring firstly to Fig 1, the illustrated cartridge (shown with its middle section removed for ease of illustration) comprises a cylinder 1 of cardboard or other biodegradable material having an axis Y - Y and a plunger 1A inserted at one end. The other end of the cylinder 1 receives an end piece 2 formed from injection moulded synthetic plastics material. The end piece 2 defines an outlet 3 having a screw threaded exterior surface 4 and a cylindrical inner surface 5. A twin-compartment chub 6 is formed from flexible laminated sheet plastics material having at least one layer specifically designed to isolate its toxic contents from the atmosphere. It is formed continuously as a tubular structure having a tuck or pleat so as to define two compartments each extending along the whole length of the chub structure. During manufacture, separate extrudable materials 7 and 8 are introduced into these compartments. The resulting filled twin tubular structure is then divided into sections by pairs of wire crimps 9A, 9B. Finally, the structure is cut between the crimps of each pair to form chubs essentially as shown at 6 in Fig 1.
During assembly, a chub 6 is inserted through the left hand end of the cylinder 1. Neither compartment of the chub is filled to maximum capacity, allowing one crimped end to be squashed and manipulated so that the crimped end projects through the opening 3. The projecting end carrying the crimp 9B is then folded over the edge of the outlet 3 and a plug 10 inserted into the latter.
The plug 10 has a lip 10A and a cylindrical body portion rounded at its free end to facilitate insertion into the outlet 3. This body portion has a flat (in alternative constructions this could be a groove) precisely dimensioned so that, when the plug is pushed home, the resulting space between the plug and the outlet surface 5 is filled by the flexible plastics material of the chub. The lip 10A has a groove to receive the folded-over end of the chub.
During manufacture, after the plug has been pushed home as shown in Fig 1, the exposed end of the chub with its crimp 9A is cut off with a knife indicated schematically at K. However, the interfitting action of the plug 10 and the outlet 3 serves to hold the discharge end of the chub closed. This prevents escape and mixing of the materials 7 and 8. A release member in the form of a cap 11 is then screwed on to the outlet 3. During a first stage of this process a cam surface 11B of a resiliently flexible internal flange 11A of the cap engages against a corresponding cam surface 10B of the plug, causing the flange 11A to bend and then spring with a snap action into a groove 10C of the plug. Reverse relative axial movement of the cap and plug is prevented by engagement of the surfaces 10D and 11C. The flange 11A and groove 10C thus form a detent, latch or locking mechanism, having the effect that, when the cap is removed by the user, the plug 10 is removed with it.
All the user needs to do therefore is to remove the cap 11, to screw a nozzle 12 (Fig 3) onto the outlet 2 and to fit the cartridge into a conventional gun. In use, the gun exerts pressure on the plunger 1A, forcing the materials 7 and 8 through the nozzle 12 where they are mixed by a helical insert 13 before being extruded in conventional manner.
A particular benefit of the embodiment that has been described is that the cardboard tube 1 can be made of sustainable and recyclable material and is less costly to supply than the conventional tubular injection moulded cartridge. Where the type of gun that includes an enclosed cylindrical cartridge holder is to be employed, the cardboard cylinder 1 is not required since the cylindrical cartridge holder will provide its function of resisting radial distention of the chub during the extrusion process.
Referring now to Fig 4, there is shown an alternative embodiment of the invention. This embodiment includes components exactly the same as those shown in Figs 1 to 3 with the exception that the cardboard tube 1 and the plunger 1A are omitted. The remaining components are placed in a conventional extrusion gun of the type that includes a permanent, i.e. non-disposable, cylinder 14 which, for the purposes of illustration is shown as transparent, though in practice this will not always be so. In this embodiment, a plunger 15 forming a conventional part of the extrusion gun and attached to shaft 16, is driven, by the action of trigger 17, directly into engagement with the chub. When all the materials have been extruded the empty chub and its associated components 2 and 12 are discarded for recycling.
In the design variant shown in Figs 5 and 6, the plug 10 is replaced by a plug 18 formed as a single moulding having two parts 18A and 18B joined by a hinge 18C. The two parts are designed to hinge closed with a small space 18D between them, dimensioned to receive exactly the end of the chub but none of its contents so that a perfect seal is formed when the two parts of the plug are held together by the interaction of the plug with the interior surface of the outlet. As for the embodiment of Figs 1 and 2, the end of the chub and the crimp are removed during manufacture, using a knife K.
Fig 7 shows another variation where, the closure means is defined by a ring 19 that surrounds the outlet so that the end of the chub is trapped by radial pressure between the outlet and the ring. As for the previously described embodiments, the excess material at the end of the chub and the crimp are removed by knife K during manufacture and before the release member in the form of cap 11 is applied. In the illustrated embodiments the cap 11 is shown as closed but this is not essential and it could equally well take the form of a ring open at both ends.

Claims

A method of preparing a container of extrudable material (7,8) starting from means (2) defining an outlet (3) for the material, closure means (10) for the outlet (3) and a flexible bag (6) that contains the extrudable material (7,8) and has a discharge end closed by a crimp (9); the method comprising the steps of
a. passing a discharge end and the crimp (9) through the outlet (3), and characterised by

b. after step a, interfitting the closure means (10) and the outlet (3), whereby the interfitting action of the closure means (10) and the outlet (3) serves to hold the discharge end closed.
A method according to Claim 1 characterised in that after step b, the crimp (9) is removed by cutting through the discharge end of the bag with a knife (K).
A method according to any preceding Claim characterised in that the closure means (10) is a plug.
A container for extrudable material comprising:
a. means (2) defining an outlet (3) for the material;

b. a closure means (10) for the outlet(3); and

c. a flexible bag (6) containing the extrudable material (7,8) and having a discharge end which extends through the outlet (3), the portion of the discharge end extending outside the outlet (3) being closed by a crimp (9), characterized in that the discharge end of the flexible bag (6) is closed and held closed by an interfit action between the closure means (10) and the outlet (3).
A container (1) according to Claim 4 characterised by a release member (11) and complementary screw threads on the release member and the means (2) defining the outlet allowing the release member (11) to be threaded onto the means (3) defining the outlet during assembly and means (11A, 10C) for locking the release member (11) and the closure means (10) together so that, unscrewing of the release member (11) in preparation for extrusion of the material (7,8), causes the closure means (10) to be withdrawn from the outlet(3).
A container according to Claim 5 characterised by a detent mechanism (11A, 10C) that engages to lock the release member (11) and the closure means (10) together when the release member (11) is screwed onto the means (2) defining the outlet during assembly.
A method according to Claim 5 or 6 characterised in that the closure means (10) is a plug
A container according to Claim 5 characterised in that the discharge end is held between the plug (10) and an internal surface of the outlet.
A container according to Claim 5 characterised in that the plug (10) has two or more parts and in that the discharge end is held between the plug (10) parts.
A container according to any of Claims 4 to 9 characterised in that the flexible bag (6) has two compartments for different extrudable materials (7,8) that react together when mixed, each compartment having an open end that extends into the outlet (3) and is pinched closed by the closure means (10).
A container according to any of Claims 4 to 10 characterised by a housing (1) defining a tubular supporting structure for the flexible bag (6).
A container according to Claim 11 characterised in that the housing (1) is defined by a single moulding of synthetic plastics material.
A container according to Claim 11 characterised in that the housing (1) is formed from a cardboard tube and an end piece (1A) that fits onto the tube and is moulded from synthetic plastics material.