EP0401222A1

EP0401222A1 - Method and device for producing articles with protruding parts

Info

Publication number: EP0401222A1
Application number: EP88910176A
Authority: EP
Inventors: Häkan SJÖGREN
Original assignee: HORDA AB
Current assignee: HORDA AB
Priority date: 1987-11-23
Filing date: 1988-11-23
Publication date: 1990-12-12
Also published as: WO1989004755A1; SE8704622D0

Abstract

Dans le procédé et le dispositif décrits qui servent à produire par moulage par soufflage des articles présentant longitudinalement une ou plusieurs courbures, une paraison (9) est acheminée à travers un moule pour l'opération de moulage par soufflage. Les parties du moule (2) présentant des cavités (3) pour le moulage sont fermées lors de l'acheminement de la paraison (9) à travers le moule et grâce à la fermeture de la cavité du moule on obtient le moulage de la paraison.In the described method and device for producing by blow molding articles having longitudinally one or more curvatures, a parison (9) is conveyed through a mold for the blow molding operation. The parts of the mold (2) having cavities (3) for molding are closed during the conveying of the parison (9) through the mold and thanks to the closing of the cavity of the mold the molding of the parison is obtained .

Description

METHODANDDEVICEFORPRODUCINGARTICLESANDARTICLE PRODUCEDBYTHEMETHODANDDEVICE

Technical field:

The present invention relates to a method to produce in a moulding machine objects showing tubular shape, tubular shape with bellows shaped parts, in the shape of hollow bodies and/or relatively thin walled objects and in applicable cases with connected devices and parts to the object. At this a tube of blow moulding material is extruded or injected through a first die in order to be blow moulded in a mould cavity in a mould. The object is removed from the mould by opening the mould or a split of the mould members.

Background:

There is a need to be able to produce products and objects in a more simple and rapid way, especially with respect to such products and objects which are to show a complicated form and which when used are exposed to such strains which can jeopardize the strength. Thus, there is a need when manufacturing of for example pipes for motors to be able to manufacture the pipes, as inlet pipes, in a more simple and rational¬ ized manner.

Technical problems:

Thus, such pipes and products are nowadays manufactured in several parts which must be assembled to form the product. Since such pipes for example from considerations of space often will show a complicated extension, they also often show an extension in several dimensions which in turn implies that the pipe must be manufactured in several parts which are subsequently assembled. Moreover, as in the case of inlet pipes, which shall show one or several bellows, it is also necessary that a bellows be manufactured as a separate part and in view of strength factors often of rubber and the remaining parts of the pipe in at least two separate parts and thereby mainly of metal or perhaps of plastic material, as also other parts, such as assembly or connecting devices and the like, whereby the bellows and the pipe parts are subsequently assembled with the aid of the assembly and connecting devices. A proposal has been made to shape such a product in one piece. This has been disclosed in west German patent 2 927 098 which presents a device in which a pipe piece is blow moulded, whereby a tube of thermoplastic material is extruded via either a fixed extruder, whereby a mould half member in a moulding tool is brought to move so that the extruded tube is placed in a mould cavity half and following the direct— ion of the mould cavity, or that a mould half member in a moulding tool is held in one position and the extruder is arranged to be able to move in accordance with the direction of the mould cavity half so that the extruded tube is placed in the mould cavity. The second half member of the moulding tool is then supplied to the first half member and blow moulding of the object is carried out. The device is, however, of a particular kind and conventional blow moulding method and moulding machine cannot be utilized. Neither in the case of such a device can possibly to the pipe piece necessary connections be moulded in one piece with the pipe piece and therefore not in the same manufacturing process, but must be moulded as separate parts for arrangement to the pipe piece after its manufacture, whereby, in addition, there is subsequent work, such as measuring of anchoring points on the pipe piece, customary hole making and assembly and anchoring of the connect¬ ions in question and similar. Such connections could be holding devices, connections of ducts, nipples and other devices in the pipe piece.

The solution:

In order to avoid seams in a tube or pipe when using a blow moulding method the extruded tube must have a diameter less than the cross sectional area of the mould cavity. Seams in such objects, which are for example exposed to mechanical stresses in the form of for example vibrations, as in the case of inlet pipes to vehicle engines, must with a view to strength factors be avoided. A bellows is moreover an example of such a part in a tube or pipe which shall absorb and distribute vibrations and other stresses. Traditional blow moulding material, such as plastic material, which should be used for this purpose, can in view of the strength factors not be utilized for these products and neither can such materials be used for a rationalized manufacturing, which are traditionally able to be vulcanized, since these cannot be blow moulded. However, a mixture of plastic and rubber material or so-called elasto- mers or thermoplastic elastomers, can be used for blow moulding and also comply with strength specifications even for the manufacture of tubes or pipes and the like with bellows. In addition, it is also possible at the same time in accordance with the invention to provide the object with connecting devices and parts in the form of a pipe, a pipe with one or several bellows, etc. during the blow moulding of the object. The purpose of the method according to the invention is thus to be able to produce a tube, pipe or similar which preferably runs in one or more dimensions and which in applicable cases shall display one or several bellows and in that respect connecting tubes, pipes or similar to the bellows and which is moulded in a tool during one and the same occasion, i.e. in one piece during one manufacturing process. An another purpose is that in applicable cases to provide such an object with connecting devices and parts which are manufactured in the tool and during the same occasion as the object and also so that such connecting devices and parts become moulded in one piece with the rest of the object. A method in accordance with the invention is characterized in that the extruded or injected tube is entered and fed through the tool or its mould cavity after the mould members of the tool, which show mould cavities for moulding of objects by blow mould¬ ing, have been closed.

The invention also relates to an arrangement for producing objects in accordance with the invention. The arrangement thus comprises a mould- ing tool with a mould cavity in which a tube of a material, which is able to be blow moulded or a thermoplastic material, is blow moulded and in applicable cases is provided with connecting devices or parts, whereby the tube is extruded or injected through a first die and after the blow moulding is taken out from the mould byopening of the mould. The arrangement is characterized in that the arrangement comprises lower and upper jaws, whereby the lower jaw or for example shaped as a pair of jaws is arranged for closure of an adjacent opening of mould's mould cavity.

According to an another characteristic of the arrangement in accordance with the invention the mould shows one or several injection moulding cavities arranged in connection or adjacent to the afore mentioned mould cavity and that the arrangement or the moulding machine comprises at least one second nozzle which is arranged for supplying of a material, which is able to be injection moulded or a thermoplastic material, to the injection moulding cavity or cavities for injection moulding of connecting devices or parts to that object which is blow moulded. The connecting devices or parts may comprise tube connections, tubules, nipples, attachment devices, such as attachment lugs and other devices of the object or in an arrangement, whereby the object in one and the same mould and during the same or substantially the same manufacturing process is equipped with such additional devices and parts.

The invention also relates to an object which is produced according to the method in accordance with the invention or in the arrangement in accordance with the invention. The object shows in this respect tubular shape, tubular shape with one or more bellows shaped parts, is in the shape of hollow bodies and/or relatively thin walled objects and in applicable cases with connected devices and parts to the object. More¬ over, the object is composed of rubber, plastic material, a mixture of rubber and plastic material or a thermoplastic elastomer or an another thermoplastic material, which is able to be blow moulded and in applic¬ able cases of a thermoplastic material, which is able to be injection moulded. The object is characterized in that the object is moulded in one piece and without showing seams along the length of the object.

In accordance with an another characteristic of the object it shows at least one bellows or one or several bellows shaped parts and/or at least one connecting device or part, for example in the shape of one or several connecting tubes, attachment devices or the like.

Brief description of the drawings:

Additional characteristics and advantages of the method, the arrangement and the object in accordance with the invention will be apparent by embodiments in the following description, whereby a simultaneous refer¬ ence will be made to the accompanying schematic drawings, of which Fig. l a shows from one side a part of a die and an extruded tube, Fig. 1 b shows from one side a die or a second die and a part of a moulding tool, Fig. 2 a - 2 c show from one side different phases of an arrangement's work mode or cycle, Fig. 3 shows from above a part of a mould and in a phase according to Fig. 2 c, Fig. 4 shows from one side a part of a mould according to an additional embodiment of the invention and with certain auxiliary equipment, Fig. 5 shows from one side an example of an object which has been produced in an arrangement in accordance with the invention and according to a method in accordance with the invent¬ ion, Fig. 6 shows from one side a part of a die according to an addit- ional embodiment of the invention, Fig. 7 shows from one side a second example of an object which has been produced in an arrangement in accordance with the invention and according to a method in accordance with the invention, Fig. 8 shows from one side a third example of an object which has been produced in an arrangement in accordance with the ^' invention and according to a method in accordance with the invention, Fig. 9 shows from one side an example of a part of an arrangement according to yet another embodiment of the invention and Fig. 10 shows from the side an example of a part of an arrangement with a mould half which is included as a part of a mould.

Best modes for carrying out the invention:

The reference designation 1 in the figures shows an arrangement or a part of an arrangement or a moulding machine or a blow moulding machine which comprises a moulding tool 2 which is openable by a split of mould members for the possibility to remove a produced article or object. The mould 2 shows a mould cavity 3 with a first opening 24 and a second opening 25. In the arrangement 1 there is a first closing device 4, such as a lower pair of jaws 4 or similar, and a second closing device 5, such as an upper pair of jaws 5 or similar. A die 7 can extrude a tube 9 which is intended to be entered into the mould cavity 3 when the mould 2 or its mould members are closed. Medium for blow moulding of the tube 9 in the mould cavity 3 is supplied via a blow nozzle 8 or in place of it a blow pipe 38.

As shown in Fig. 1 a, an extruder or a die 27 extrudes a tube 29 which shall be received by a moulding tool for blow moulding against the mould surfaces in the mould's mould cavity. Hereby, a cutting device 31, as a knife, can be arranged to separate the tube 29 from the tube or the material which is in progress. This displays a current method for a blow moulding machine. Fig. 1 b shows in addition that in a blow moulding machine the moulding tool 22 can collect the extruded tube 29 and contain it in its mould cavity 23 and then move itself to a blowing station for blow moulding of the tube with the aid of a blow nozzle 28. In this case the blow nozzle 28 is inserted in the tube 29 in its posit¬ ion in the mould's 22 mould cavity 23. In addition it is apparent that the extruded tube has a diameter less than the cross sectional area of the mould cavity 23. Fig. 2 a - 2 c show schematically an embodiment of an arrangement in accordance with the invention in different production phases. Thus, it is apparent that in the arrangement 1 a moulding tool 2 with a mould cavity 3 is provided with lower jaws 4 and upper jaws 5 in connection with adjacent openings 24 and 25 in the mould's mould cavity 3. It is also apparent that the mould or its mould halves or members are closed in Fig. 2 a and closed prior to that a die 7 or an extruder extrudes a tube 9 which is entered and passing through the mould's 2 mould cavity 3 in the mould so closed. Subsequent to this and before the blow moulding with a blow device 8, the jaws 4, 5 close. In the case of jaws in the shape of jaws arranged in pairs these are moved towards each other, as indicated by the arrows 15 in Fig. 2 b, whereby the lower pair of jaws 4, as well as the upper pair of jaws 5 close the tube 9 with material from the tube 9 lieing between the jaws, see Fig. 2 c. In one type of moulding machine or in the case of an extruder, the jaws 5 can show a recess so that the tube is not fully closed and an aperture 6 is obtained in the tube so that the blow nozzle 8 can be brought into the interior of the tube 9 for blow moulding, see also Fig. 3. In another type of moulding machine with an ejector or accumulator unit 36 with a die 37, and which ejects or presses out a predestinated quantity or volume of the material, which is to be extruded, the jaws 5 close to the blow pipe 38 with inter¬ vening parison 9, see the embodiment examples according to Figs. 6 and 9. The blow pipe 38 is at the ejector or accumulator unit arranged fixed. Irrespective of the form of the moulding machine and its moulding tool a closed tube 9 or parison will be achieved for blow moulding in the mould cavity 3 in the mould 2. It is important according to the present arrangement and method that the tube 9 or parison is extruded into the mould's 2 mould cavity 3 in a closed mould or closed mould halves or members in the moulding tool, as also is shown in the figures. After the blow moulding the mould 2 is opened by a split of the mould halves or members, as shown by the arrows 17 in Fig. 2 c, and the blow moulded object 10 can be removed. The jaws 4, 5 have at this been moved aside or returned to their initial position. After this, the mould halves or members close again or the mould 2 and the tube 9 or parison is extruded down, into and through the mould's 2 mould cavity 3.

An object 10, which can herein be produced is for example an inlet pipe to vehicle engines and which shows a bellows 11, curved sections 14 and openings 12 and 13 which are not only directed in opposite directions but can also be directed or open out in planes at an angle to each other and the curves 14 can be in different planes and the object 10 runs in two or at least three but also in more dimensions.

Fig. 4 shows that if necessary different means can be utilized to simplify the feeding of the tube 9 or parison through the mould's 2 mould cavity 3. Thus, the mould 2 can show ducts 18 or holes through which supporting air or a corresponding medium can be supplied to form an air cushion or similar in curves in the mould cavity 3 and thus guide the tube or parison without it fastening in different passages in the mould cavity 3. For the same purpose the ducts may instead comprise vacuum ducts to form low pressure points in the mould cavity 3. In addition, a suction apparatus 19 can be supplied to the mould's 2 opening 24 and tightly connected to suck the tube 9 or parison through the mould cavity 3 or form a low pressure in the mould cavity 3 and in so doing facilitate the feeding of the tube 9 or parison in the mould cavity. A fan 20 in a connectable pipe 19 is a device in this respect. The suction apparatus 19 may instead comprise a vacuum suction apparatus or an injector which blows air and generates low pressure in the mould cavity 3.

Fig. 6 shows a die 37 to an ejector or accumulator unit 36 with a fixed blow pipe 38. At this, the material or the parison 9 is ejected or pressed out from the die coaxially around the blow pipe 38, whereby a tube 9 is produced more rapid for blow moulding. In addition, it should in this respect be possible to introduce a tube or parison in the mould cavity of closed mould halves or members in a moulding tool 2 for fhe production of more complicated forms of objects. When the mould cavity shows curves of more than 90 degrees and for simplifying the feeding of the parison, a vacuum pump, a suction device, an air blower or the like can be used. Examples of such means are a vacuum suction apparatus or an injector 19 and in combination with the formation of air cushions or the like. By achieving a low pressure in the mould cavity 3 an improved guid- ing of the tube or parison is attained at the same time as the ejector or unit gives an air current. The injector or vacuum pump 19 can be tightly connected round the opening 24 of the mould cavity 3 in order to fortify the flow achieved through the mould cavity 3 which flow guides the tube or parison or that the tube or parison follows the air flow when it is ejected or pressed out when ejection or extrusion from the die takes place. After the feeding of the tube 9 or parison through the mould cavity 3 the jaws 4 and jaws 5 close.

Figs. 7 and 8 show objects 10 which extends in at least three dimens¬ ions, i.e. the objects extend or turn in three planes or directions. The object runs or curves in one direction, partly in another direct¬ ion but the whole object also turns or curves in a third direction or across or horizontally according to the figures.

In accordance with the invention the object 10 can be furnished with connecting devices 21 or parts, such as tube connections 26, tubules, attachment devices, attachments lugs and other additional parts which in known methods must be manufactured as separate parts and afterwards be assembled to an object 10. Such subsequent processing and separate manufacturing of connecting parts and the like can be avoided when utilization the method in accordance with the invention, since the connecting parts can be produced at the same time, in the same mould or moulding machine and in the same or substantially the same manufactur- ing process or manufacturing cycle, as the object itself. Thus, Figs. 9 and 10 show a moulding tool 2 which is provided with one or several mould cavities 33 which connect to the mould cavity 3 for blow moulding. The additional mould cavities 33 communicate via ducts 35 with second nozzles 39 or injection mould nozzles or extruders for supplying a thermoplastic material or a material, which is able to be injection moulded, to the injection mould cavity 33 or injection mould cavities. Where the connecting devices 21 shall be formed as tubes 26, nipples or similar, cores 34 are arranged, which can be inserted into the inject¬ ion mould cavities 33 via channels 32. Thus, an object or a product can, as current is composed of several parts 10, 21, 26, 30 or several different bodies, be produced at the same time in accordance with the. invention.

Thus, with the ejectors or unit's nozzle 37 a parison 9 is ejected into the closed moulding tool 2 or the mould halves or members and fed through the mould cavity 3. The jaws 4, 5 pinch the parison 9 and the upper jaws 5 pinch the parison against the blow pipe 38. The cores 34, if such are to be used, have already been inserted or is inserted into their positions in the injection mould cavities 33, after which the material for injection moulding is supplied. This material can be supplied to the mould halves or the mould 2 and the injection mould cavities 33 as soon as the moulding tool 2 or the mould halves have obtained their closed position. It is in fact the case that the inject- ion moulding of these devices or parts can take place before the blow moulding or simultaneously with the blow moulding of the object. When the injection moulded devices or parts and the blow moulded object are still hot, the object and the injection moulded devices or parts are melted together in the area 16 for their adjoining. By this a durable connection of devices or parts to an object is attained, this connect¬ ion often being stronger or has more strength than the actual object. An enlarged section 40 can be arranged in the moulding tool 2 at the connection area between the mould cavity for blow moulding and the injection mould cavity or cavities. Before the moulding tool 2 is opened or the mould halves are separated for removal of the produced object 10, the cores 34 are in applicable cases first displaced out from the mould 2 or the mould halves and from such channels 32 as are included. The jaws 4, 5 have in conformity with what has been previously mentioned been removed or returned. The process is rational and rapid and is repeated for production of numerous objects one after the other.

One work cycle for the arrangement is as follows, namely that the mould halves or members are brought together, cores to be used are inserted into the injection mould cavities, a hose communicating with a vacuum pump, suction apparatus or injector is displaced to the combined mould, halves and brought to surround an opening which leads to the mould cavity in the mould halves. A tube or parison of the material is extruded or pressed out with an extruder or accumulator machine and introduced into the unified mould halves and through the mould cavity and out through the said opening while a certain pressure and flow is permitted through the blow pipe so that supporting air is held into the tube or parison. The said hose to the vacuum pump or the like is then moved away from the unified mould halves. Jaws are shifted to closure or pinching of the extruded or ejected material tube or parison which has been fed through the mould cavity of the unified mould halves and closes the tube or parison under the mould halves. Jaws are as well shifted for closure or pinching of the material tube or parison under the extruder die or the accumulator machine's outlet opening or die, whereby the extruded or ejected material tube or parison is brought to be pinched between the jaws and the blow pipe for the input of blow air for the blow moulding which takes place via an increase in the pressure and flow. Cores have in applicable cases been shifted to their intended positions in the moulding tool or mould halves if connection devices or parts of the previously mentioned type are to be present. The increase of pressure and flow of the blow air takes place and air is injected into the closed material tube or parison for blow moulding and in applic¬ able cases simultaneously or just before or just after, depending on the setting of the injection moulding arrangement and product to be produced, the injection moulding nozzle or the nozzles inject the injection mould¬ ing material into the moulding tool via ducts and to the or those mould cavities which are arranged for injection moulding and located in the mould halves or in injection moulding tools. The blow moulding can take place with a delay of a few tenths of a second. When the injection mould¬ ing material has been introduced the nozzle or material supplying device of the injection moulding unit returns. After the blow moulding and also injection moulding, if injection moulding has took place, the said jaws are shifted to the initial position, the mould halves are separated and the blow moulded and injection moulded object is removed from the mould¬ ing tool.

Without exceeding the scope of the concept of the invention, modificat¬ ions of the invention should be possible. Thus, the method can be used in various kinds of moulding machines for production of objects. Further, the number of injection moulding cavities can differ, as well as inject¬ ion moulding units fOr the injection moulding. The shape and location of the injection moulding cavities can be differently for producing varying connecting devices and parts. The shaping of the jaws can be different. The objects, which shall be manufactured, can be of all sorts, as containers, pipe connections, tubes, etc. but with a duct or conduit which can be blow moulded. The materials to be used are able to be blow moulded and injection moulded. It can be convenient for the production of certain objects to use thermoplastic elastomers for the body to be blow moulded. The method, the arrangement and the objects, which shall be produced, are thus not restricted to what has been indicated by the embodiments but soley by the following claims.

Claims

Claims:

1. A method for producing objects (10) in a moulding machine, the objects show tubular shape, tubular shape with bellows shaped parts, are in the shape.of hollow bodies and/or relatively thin walled objects and in applicable cases the objects show connected devices (21) or parts, whereby a tube (9) of a blow moulding material is extruded or injected through a first die (7) in order to be blow moulded in a mould cavity (3) in a moulding tool (2) after which the object (10) is removed from the mould (2) by opening the mould, characterized in that the extruded or injected tube (9) is entered and fed through the mould (2) or its mould cavity (3) after the mould (2) is closed.

2. A method in accordance with claim 1, characterized in that said connected devices (21) or parts are injection moulded in the same mould (2) in connection with the said mould cavity (3).

3. A method in accordance with claim 2, whereby at least one connecting device (21) shall comprise a tubular device (26), characterized in that at least one core (34) is entered in an injection moulding cavity (33) and removed from the mould before the mould (2) is opened by a split of the mould members.

4. A method in accordance with claim 1, 2 or 3, characterized in that a first opening (24) of the mould's (2) mould cavity (3) prior to the blow moulding is tightly closed and that a second opening (25) of the mould's (2) mould cavity (3) is closed with the aid of a second closing device (5) which via the tube (9) strike a blow pipe (38) or leaves an aperture (6) for a blow nozzle (8) which can be inserted through the aperture.

5. An arrangement for producing objects in accordance with any of the. claims 1 - 4, whereby the arrangement comprises a moulding tool (2) with a mould cavity (3) in which a tube (9) of a blow moulding material is blow moulded and in applicable cases provided with connecting devices (21) or parts, whereby the tube (9) is extruded or injected through a first die (7) and after the blow moulding is removed from the mould (2) by opening of the mould, characterized in that the moulding tool (2) comprises lower and upper jaws (4, 5), whereby the lower jaw (4) or for example shaped as a pair of jaws is arranged for closure of an adjacent opening (24) of the mould's (2) mould cavity (3).

6. An arrangement in accordance with claim 5, characterized in that the upper jaw (5) or the upper jaw shaped as for example a pair of jaws is arranged to close a second and adjacent opening (25) of the mould's (2) mould cavity (3) or during the closure of the mould cavity's opening via the tube (9) strike a blow pipe (38) or leave an aperture (6) to the tool's (2) mould cavity (3) and/or the interior of the tube (9) to make a passage for a blow nozzle (8).

7. An arrangement in accordance with claim 5 or 6, characterized in that the mould (2) shows one or more injection moulding cavities (33) arranged in connection or adjacent to the said mould cavity (3) and that the arrangement or moulding machine comprises a second nozzle (39) which is arranged for supplying a material, which is able to be inject¬ ion moulded, to the injection moulding cavity (33) or the injection moulding cavities for injection moulding of connecting devices (21) or parts to the object (10), which is blow moulded.

8. An arrangement in accordance with claim 7, whereby the connecting devices (21) or parts comprise tubes (26), thin walled organs or the like, characterized in that the arrangement comprises one or several cores (34) which are arranged displaceable into the injection moulding cavities (33) and retractable from the mould (2).

9. An object produced according to the method or in the arrangement in accordance with any of the claims 1 - 4 and 5 - 8 respectively, whereby the object (10) shows tubular shape, tubular shape with bellows shaped parts, is in the shape of a hollow body and/or a relatively thin walled object and in applicable cases with connected devices (21) or parts to the object and composed of rubber, plastic, a mixture of rubber and plastic or of a thermoplastic elastomer, characterized in that the object (10) is moulded in one piece and without showing seams.

10. An object in accordance with claim 9, characterized in that the object (10) shows at least one bellows (11) or one or several bellows shaped parts and at least one connecting device (21), for example in the shape of one or several connecting tubes (26), attachment devices or the like.