PROCEDURE AND MACHINERY FOR THE PRODUCTION OF AN ASSEMBLED OBJECT

Abstract: The invention concerns a procedure for the manufacture of an assembled object intended for repeated assembling and disassembling, e.g. a tube (1) with matching cap (4), and a machine for the execution of this procedure. According to the invention the tube (1) and the cap (4) are cast in the same mould (7) and ejected simultaneously and assembled in the exact position they are to have when used. This can suitably be done by first casting the part (4), which at the boundary surface is placed outermost. When it has assumed its final shape, it serves as an independent mould when producing the other part (1). The first cast part (4) thus contribuates to the securing of the core system (9, 10, 11) for the other part (1), whereby the wall thickness of this part can be made especially uniform and thin. The machine for the execution of the procedure can thus cast e.g. the assembled cap (4) and tube (1), and it can, therefore, also be adapted to perform an automatic filling, sealing and possibly stamping of the tube.

Description: PROCEDURE AND MACHINERY FOR THE PRODUCTION OF AN ASSEMBLED OBJECT FIELD OF INVENTION The invention concerns a procedure to cast an object consisting of at least two separable parts, where each separate part is intended especially for a repeated separating and assembling by means of hands only, such as a plastic tube with its matching cap. The invention also concerns a machine for the performance of this process. DISCUSSION OF PRIOR ART There are a number of. known methods of producing assembled objects, which are meant for a repeated separation and assembling like a tube and its cap. But in all these cases each part is cast, either in its own separate mould, or in the same mould, but placed separately next to each other, so that the parts are not assembled into their final position until the casting and the ejection from the mould have taken place. In the case of a tube and its cap the two parts will be cast in separate moulds, each in its own material, and normally in two different casting machines. Then the cap and plastic tube have to be put together, usually in an automatic machine, before the tube is filled with its contents and sealed, just as the labelling or stamping of the tube has to be fitted into this procedure. SUMMARY AND OBJECT OF THE INVENTION The method according to the invention aims at simplifying and automatizing the above procedure. The invention concerns a method of producing an assembled object as mentioned in the characterizing part of claim 1. By casting the parts of the object meant to be assembled in the same machine, in the same mould and practically at the same time, and by ejecting them from the mould simultaneously and assembled in the exact position which they are to have when they are used, a number of advantages are obtained, in this case exemplified by a plastic tube and its matching cap: As the cap is cast in its proper place on the tube before the ejection from the mould, and thus does not need to be placed on the tube after the casting, considerable economies are obtained in time, storage capacity, and possible complications when placing the cap correctly on the tube. As the tube is made in the mould with the cap mounted, there is also the possibility that the tube can be filled with its contents and sealed then and there, before it is ejected from the mould with its cap correctly mounted. This means that the whole procedure, from the casting of the tube until the ejection of the filled, sealed and purposefully also stamped tube, can be made as a unity in one machine. This will result in a cheaper, simpler, and improved as well as sterile way of producing materials in tubes. And to such a degree that it may create new and better outlets for this type of products. A specially suitable production procedure for assembled objects according to the invention is that the part of the object which, in the mutual boundary surface, is placed on the outside in relation to another part of the object, will be cast first. When the first cast part has assumed its final shape, it can serve as an independant moulding part at the production of the other part(s) of the object. The advantages of the production being made in this order is that when the outer part, in this case the cap, is cooled down after the casting, it will shrink to smaller dimensions both on the outside and the inside as the thermal coefficient 'a' of expansion is positive in the term: L τ = L t (1 + a (T-t)). The other part of the object, in this case the tube itself, is cast immediately after this in the same mould with its top inside the cap, possibly only after the injection of a parting agent, e.g. silicon spray. When the top of the tube now cools down, it will shrink inside the cap and thus create a very small, but noticeable distance to the cap everywhere, which will ease the unscrewing of the cap when used and the later repeated unscrewings and screwings on. The injection of a silicon spray or other parting agents may be spared completely if the material of the cap is different from the material of the tube in such a way that they are not welded together, but on the contrary repel each other. The material for the cap can thus suitably have a softnening temperature range which is noticeably higher than the temperature where the material for the tube itself is cast, so that sticking together is avoided. It should be noted that as the cap is cast first, it can contribute to the fixing of the core of the tube in its right place in the mould, as the core would otherwise easily be shifted to one of the sides when the tube materialed is injected into the mould. This ensures a uniform thickness of the walls of the tube, which can thus be made thinner saving both material and cooling time. BRIEF DESCRIPTION OF THE DRAWING The more detailed advantages and presentation of the invention will appear from the drawing and the description. Fig.l gives a sectional view of a tube with mounted cap Fig.2 shows a mould for production of both cap and tube Fig.3 shows same in a different position, and Fig.4 shows same in a third position. DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1 shows the upper part of a tube 1, whose top 2 has walls so thick that it can hold the thread 3, by means of which it can secure a matching cap 4. The cap 4 has its own thread 5 and a downwards pointed protuberance 6, which may be used to secure the core during the casting. Fig. 2 shows a mould 7 for the production of both the tube 1 and its matching cap 4. In the mould 7, which forms the outer limit of the cap 4, there is an inlet 8 for plastic material for the cap 4. The inner limit of the cap 4 is defined by a system of suitably concentric core parts consisting of stick 9 at the centre, which has been suitably placed in the middle of the tube 1 and the cap 4. Around the stick 9 there is a pipe- shaped core part 10, which at the top has been designed to form the thread 5 of the cap and the protuberation 6 of the cap. On the outside of this pipe-shaped core part 10 there is the outermost pipe-shaped core part 11, which on fig. 2 is in the uppermost position and hereby forms the limit of the lowest surface of the cap 4. In the shown position injection of the material for the cap can take place through the inlet 8, and almost at the same time the injection of the material for the tube can suitably be started through another inlet 12 into the tube pipe 13 at an adjusted speed. When the material in the cap 4 has hardened satisfactorily, the tube pipe 10 is drawn downwards and out of the cap 4, which is held in place in the mould 7 by the outermost pipe-shaped core part 11 during this procedure. At the same time a parting agent, silicon spray, may be injected on the inside of the cap 4, e.g. through a nozzle in the central stick 9 (not shown on the drawing) . Now the outermost core part 11 is drawn downwards and a little away from the cap 4, thus allowing the tube material to flow into the top 2. The thus obtained placing of the mould's parts is shown in fig. 3. Fig. 3 shows the placing of the three parts 9, 10 and 11 of the core during the finishing of the casting of the tube pipe 13 and the top 2, the finished cap 4 now serving as a mould, while the protuberation 6 fixes the stick 9, so that the core is not shifted to one of the sides, to ensure a uniform and small wall thickness of the tube. When the tube material has hardened satisfactorily, all the core parts 9, 10 and 11 are drawn out of the tube, but possibly not till the mould has been opened, e.g. in the cross section shown on the drawing, whereafter the tube can be stamped or a label stuck on by a fairly simple automatic procedure, which has not been shown on the drawing. Fig. 4 shows the uppermost part of the empty tube 1 still placed in the mould 7, but all the core parts 9, 10 and 11 have been removed. The tube can now be filled with its contents, e.g. through a connecting piece mounted at the bottom, but not shown on the drawing, and there may also be a suitable welding mechanism at the bottom, not shown on the drawing, that can seal the tube after the filling. Now the completely finished tube with imprint and contents is ready to be ejected from the mould. Besides the examples shown on the drawing there may be other ways of conducting the procedure according to the invention and the machine for the production of an assembled object. As an example of this the use of sandwich moulds can be mentioned, as well as a special rotation principle. For this last variation of the production method an injection moulding machine may be used, where the fixed part and the movable part can be turned, in proportion to each other, around an axis placed centrally in the movable part's direction of travel. Only one part needs to be able to turn, just as the turning capacity can possibly and more suitably be built into one of the moulding parts. The gradual turning, which is suitably made in the same direction all the time, may have the following stages: First the cap is cast, e.g. in the stationary part, while the movable part has a protruding core, which forms the inside of the cap. The movable part is now drawn away from the fixed part so that the core goes clear, while the cap remains in the fixed part. The movable part is now turned until the tube mould with its core is outside the cap, which serves as a mould for the tube when the two moulding parts are brought together, possibly after a parting agent has been applied. Then the tube is cast, the core is drawn out, and the tube is moved to the next position, where for instance the text may be imprinted. However, the printing may take place before the core has been drawn out. At the next position the tube can be filled, at the next position it can be sealed, e.g. by welding, and at the last position the now finished, filled and sealed tube is ejected from the mould, which now moves forward and repeats the procedure. The above rotation principle may also take place in a different way, e.g. by having several procedures at the same stage. The cap and tube may be cast separately and suitably in separate moulds and then pressed together in the mould, followed by filling, sealing, stamping, and ejection as a body from the mould.

Claims: CLAIMS : 1. The invention concerns a procedure to cast an object consisting of at least two separable parts, where each part (1, 4) is intended especially for a repeated separating and assembling by means of hands only, such as a plastic tube (1) with matching cap (4), c h a r a c t e r i z e d by the fact that at least the two parts (1, 4) are ejected from their common mould (7) at the same time and joined together in their final positions. 2. Procedure for the production of an assembled object as mentioned in claim 1, c h a r a c t e r i z e d by the fact that at least one of the separable parts (4) of the object is cast first, and after having assumed its final form serves as a mould for the production of at least one of the other parts (1) of the object. 3. Procedure for the production of an assembled object as mentioned in claim 1, c h a r a c t e r i z e d by the fact that before the first cast part (4) is used as a mould, a parting agent is applied to it, e.g. a silicon spray. 4. Procedure for the production of an assembled object as mentioned in claim 1, c h a r a c t e r i z e d by the fact that the part of the object (4) which in the mutual boundary surface has been placed outermost in relation to another part (2) of the object is cast before the last mentioned part. 5. Procedure for the production of an assembled object as mentioned in claim 1, c h a r a c t e r i z e d by the fact that the first cast part (4) can be used to secure a core (9, 10, 11), possibly by the first cast part having a protuberance (6) or similar. 6. Procedure for the production of an assembled object as mentioned in claim 1, c h a r a c t e r i z e d by the fact that a core part (11) can be placed in such a way during the casting that the casting of the other part (1) of the object- takes place in at least two stages, and preferably in the most thin-walled area. 7. Procedure for the production of an assembled object as mentioned in claim 1, c h a r a c t e r i z e d by the fact that the two parts (1,4) are cast separtely, suitably each in its own mould, and then they are pressed together in the mould (7) before a possible stamping, filling, sealing and ejection. 8. Procedure for the production of an assembled object as mentioned in claim 1, c h a r a c t e r i z e d by the fact that the part (4) of the object which is cast first has a higher softening area than the material of the following part (1). 9. Machine for the execution of the procedure for the production of an assembled object as mentioned in claim 1, c h a r a c t e r i z e d by the fact that the core in the tube is made up of at least two, suitably three, concentrically placed and mutually movable core parts (9, 10, 11). 10. Machine for the execution of the procedure for the production of an assembled object as mentioned in claim 1, c h a r a c t e r i z e d by the fact that the mould (7) for the two parts (1, 4) is also equipped with mechanisms for the filling of the object with its contents and possibly also for the sealing of the part (1) before the final ejection of the mould.

Inventors: GRAM JES TOUGAARD, GRAM, JES, TOUGAARD
Applicants: GRAM JES TOUGAARD, GRAM, JES, TOUGAARD
Application year: 1990
Main classification: B29D23
IPC codes: B29C45, B29D22, B29D23, B29L1, B29L22, B65D35