AU695245B2

AU695245B2 - A method of filling a mould for moulding a tube head on a tubular body portion of a tube

Info

Publication number: AU695245B2
Application number: AU77448/94A
Authority: AU
Inventors: Freddy Scheifele
Original assignee: MAEGERLE KARL LIZENZ; KMK Lizence Ltd
Current assignee: KMK Lizence Ltd
Priority date: 1994-09-19
Filing date: 1994-10-26
Publication date: 1998-08-13
Anticipated expiration: 2014-10-26
Also published as: EP0728064B1; EP0728064A1; WO1996009151A1; CH689204A5; DE59508318D1; AU7744894A

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT a 4*a* Applicant: ryKW(na Invention Title: 1 A METHOD OF FILLING A MOULD FOR MOULDING A TUBE HEAD ON A TUBULAR BODY PORTION OF A TUBE Cr C C.( C C C C C C (C The following statement is a- full descript~ton of this invention, including the best method of performing it known to me/us: KK-86875/CH A method of filling a mould for moulding a tube head on a tubular body portion of a tube The invention concerns a method of filling a mould for moulding a tube head comprising plastic material, on a tubular body portion of a tube.

Two procedures have been developed for moulding a tube head on a tubular body portion of a tube. A first moulding procedure is characterised in that a prefabricated tube head is connected to a tubular body portion of a tube, while the second procedure involves joining the tubular body portion of the tube and the tube head during the shaping operation, that is to say while forming the tube head. The 10 invention lies in the field of the latter procedure, that is to say simultaneous shaping of a tube head, and moulding it on and joining it to a tube body portion, also referred to as simultaneous moulding, for the sake of brevity.

A simultaneous moulding mr hod is known in which a portion of material is separated from a vertically downwardly directed flow of material from a material producer supplying heat-plasticised plastic material, the portion of material being in the form of an annular blank which is introduced into a mould cavity of a mould. Then, by closure of the mould cavity, by means of a mandrel or bar with the tabular body portion of the tube carried thereon, the annular blank is pressed to form a tube head which is joined to the body portion of the tube. The particular aspect of this method is that the separated blank is introduced into the mould cavity without the use of mechanical aids. In that way, the melting heat is only slightly reduced, in regard to the 25 blanks, prior to the pressing operation, while that procedure also provides for substantially eliminating troublesome local cooling effects which would result in local preliminary crystallisation phenamena and thus give rise to defective tube heads. The aboveindicated advantages of the known method were achieved in conjunction with plasticisable plastic materials of a simple to ccmplex chemicaf'r' lt:~P !S r 2 composition, the latter also being referred to as high-tech plastic comnpounds or, briefly, high-tech compounds. With further advances in developmnent, that is to say in the degree of complexity in the hightech comipounds, it is becomning clear in regard to the processing thereof that the known method of introducing the material into the mould cavity will impose limits in terms of production procedure. One of those limits is due to the fact tlzt it is only possible to exert a limited influence on the charging time of the rmould cavity (with a constant mould cavity height and a constant speed of downward movement, the charging time inevitably remains constant), while a further limit is due to the fact that the portions of material cannot be disposed in the mould cavity in the same position in an accurately reproducible manner. For satisfactory processing of high-tech comnpounds for exeimple specific temperature gradients (temperature drops in respect of the portions of material on a stretching unit between the material-producing dev,ce and the deposit surface on the bottun of the mrould) have to be maintained; with a predetermined mould cavity, it is only possible to influence such temperature gradients by way of the speed of downward iroveirent. Also to be incorporated in the temperature gradients is cooling of the portion of material af ter the mould cavity has been charged, until the portion of material is subjected to the pressing action, that is to say, the residence time of the portion of material in the mould cavity until it is subjected to the pressing effect. That part of the temperature gradient (temperature drop over a distance of zero) can only be controlled if the portions of material are always deposited in the mould cavity in the same position. If the portions of material are deposited in :different ways, for example in displaced relationship with the normal position, that results in different cooling effects, and that has a disadvantageous effect on processing of the plastic material within the limrits of narrow temperature gradients. i Apparatuses for carrying out the method, so-called head machines, are high-value and long-lasting econocmic goods which must be capable -3 of processing plastic materials from a very simple to a very complex ccposition, depending on the respective requirements made in terms of the properties of the material, for example the diffusion characteristics of the tube heads. The development of a method with which only highly complex plastic materials can be processed would represent an isolated and limited solution in terms of the total spectrum of processable plastic materials, and such a solution would not find acceptance from technical and ccrmercial points of view as the user is dependent on a method of processing plastic materials of all degrees of ccmplexity.

Taking the above-indicated state of the art and having regard to the requirement that a method of processing highly complex plastic materials must be equally suitable for processing plastic materials of ez* a simple composition, with good results, the object of the present 15 invention is to provide a method of filling a mould for the production 4 t of tube heads from plasticisable plastic materials, contained in a "wide range of complexity.

tt In accordance with the invention, there is provided a method of filling a mould for moulding a tube head of plastic material, on an open end of a tubular body t, portion of a tube, wherein a portion of material is separated, as a blank, from a vertically downwardly directed flow of plasticised plastic material, introduced into a mould cavity of a mould, and then pressed by means of a mandrel with a tube body portion carried thereon, to provide a tube head which is connected to the tube body portion, characterised in that: i the portion of material is received by an auxiliary carrier which is displaceable between the material-supplying device and the bottom of the mould cavity, and the portion of material is introduced into the mould cavity at controlled speeds which ca.- be equal to, greater than or less than the speed of a free fall of the portion of material.

If I H;\susan\keepspci\7744a-94-CK14l.DXC 29/06/98 -4 Further advantages features and details of the methol according to the invention are apparent from the following description of a preferred emibodiment in conjunction with an apparatus which is suitable for carrying the method into effect.

in the drawing: 4* 6 V 9 a tt#t 4t4e 6S~4

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It, *6 4 1 I 4-i C ~'1 6i~ (v) 4;" H:Nssn\keepsp-ci77448-94-ll.I .DOC 29/06/98 Figure 1 is a diagrammatic plan view of an apparatus for moulding a tube head on to a tubular body portion of a tube, Figure 2 is a side view of the apparatus in section taken along line II-II in Figure 1, and Figure 3 shows a view on an enlarged scale as a detail of the filling device and the mould shown in Figure 2, with the mould in section, as a side view.

Figure 1 shows an apparatus 10 for moulding a tube head 17 on a tubular body portion of a tube, hereinafter referred to for he sake of brevity as the head machine 10, which is suitable for example for carrying out the method according to the invention, although use of the method according to the invention is not restricted to a head machine 10 of the kind and configuration described hereinafter. The head machine 10 includes a turntable 11 with working stations 1 to 8.

Disposed on each working station at an identical distance from the centre of the turntable 11 is a mould 14. In working station 1, a horizontally disposed mandrel or bar 12 is loaded with a tubular body portion 13 of a tube. After the loading operation the turntable 11 rotates into working station 2 in a cyclic or step-wise manner i" 20 (through In working station 2 the mould 14 is loaded with plasticised plastic material from an extruder 15. During the loading operation in the working station 2, the mandrel 12 with tube body portion 13 is disposed in a horizontal position, as shown in Figure 2.

After the loading operation the turntable 11 with mandrel 12 i'th tube body portion 13 and mould 14 rotates into working station 3. During the rotary movement the mandrel 12 pivots into a vertical position and is moved into the mould 14 by means of an elbow lever or crank 16. At the end of the entry procedure in working station 3, that is to say in the pressing position of the mould 12, a tube head 17 is moulded in 30 the mould 14, and at the same time the tube body portion 13 is joined to the tube head. Upon further rotary movement of the turntable 11 t, into working station 4, the elbow lever or crank 16 canes out of irl

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Si i if 3/3 rr m^engagement in relation with tne mandrel 12. In working station 4 the mandrel 12 is held in the pressing position in the mould 14 by means (not shown). The item passes through the working station 4 in a cyclic or step-wise manner for cooling of the tube head 17 in the mould 14.

The same applies in regard to an unchanged position for the mould 14 and the mandrel 12, for the working station 5. Between the working station 5 and the working station 6 the mandrel 12 with the tube body portion 13 carried thereon and the tube head 17 moulded on to the tube body portion is firstly moved vertically out of the mould 14 and, after having been moved out of the mould, it is pivoted into a horizontal position. After the conclusion of the next stepping movement, that is to say in working station 7, a rotary closure member 19 is applied to the tube head 17 by a screwing-on device 18. After further rotary movement, in station 8, a tube 20 is removed frcm the mandrel 12 and taken away from the head machine 10 so that, after further rotary movement into working station 1, the mandrel 12 can be loaded again with a tube body portion 13. As can be seen from Figure 1, on its turntable 11 the head machine 10 has a total of eight moulds 14 (also referred to as female mould portions 14) and eight mandrels 12 (also referred to as male mould portions 12), of which there are in each case always three in engagement in working stations 3, 4 and to provide a shaping action in respect of the tube head 17 and at the same time to connect the tube body portion 13 to the tube head 17.

Figure 2 is a side view of the working station 2, which includes 25 the invention, in section taken along section line II-II. The turntable 11 rotates about a stationary shaft 25 and is driven with a stepwise motion by way of drive means (not shown). Near the outer .y t ?periphery of the turntable 11, female mould portions 14 are fixedly fitted into the turntable 11. The female mould portions 14 have a 30 mould cavity 26 whose lower end corresponds to the shape of a tube head 17. Disposed above the mould 14 in working station 2 is a material-supplying device 15 which discharges plasticised plastic i.

IN,~ 7 material into the mould 14. The material-supplying device 15 and the mould 14 are described in detail with reference to Figure 3.

It will be seen from Figure 2 that the mandrel 12 with tube body 13 is in a horizontal position in the working station 2. The mandrel 12 is adapted to be pivotable into a vertical position about a shaft 29 between two mounting brackets 28 on the turntable 11. For that purpose, the arrangement includes a pivot portion 30 which, at one end which is towards the turntable 11, has a tooth arrangement 31 cooperating with a horizontally displaceable toothed bar or rack 32.

When for example the thrust bar 33, at whose forward front end the rack 32 is arranged, is displaced in a direction towards the stationary shaft 25, the pivot portion 30 is pivoted through up to into a vertical direction by means of the co-operation of the tooth arrangement 31 and the rack 32. The thrust bar 33 is slidably carried ;H in two guide brackets 34 which are arranged at a radial spacing.

Disposed between the guide brackets 34 is an entrainment member which is fixedly connected to the thrust bar 33 and which is in engagement with a control disc 36. The control disc 36 is stationary relative to the turntable 11, that is to say, it does not rotate therewith. A control groove 37 in the control disc 36 is so arranged that it moves the entrainment member 35 with thrust bar 33 between the c guide brackets 34, at the same time pivoting the pivot portion 30, on the one hand in a direction towards the stationary shaft 25 and on the other hand towards the outer periphery of the turntable 11.

The pivot portion 30 is provided with a preferably round guide I shaft 38 which, in Figure 2, projects from the pivot poprtion 30 in such a way as to extend horizontally in a direction towards the stationary shaft 25. If the pivot portion 30 were pivoted through into a vertical position, the guide shaft 38 would project upwardly from the pivot portion 30, extending parallel to the stationary shaft Disposed axially displaceably on the guide shaft 38 is a mandrel holder 39 which carries a mandrel 12 shown in Figure 2, with a tube 7 81 8 body portion 13 pushed thereon, in such a way as to project from the mandrel holder 39 in a direction towards the mould 14. At its free end the guide shaft 38 has a roller 40 which, co-operating with the elbow lever or crank 16 in the working station 3, that is to say after the mandrel 12 has been pivoted into the vertical position, causes the mandrel 12 to pass into the female mould portion 14, by sliding along the guide shaft 38. In that connection, inaccuracies in respect of individual female mould portions 14 are ccmpensated by a prestressing spring 71. In the entry position (working stations 4 and 5) the male mould portion or mandrel 12 is held in the female mould portion 14 in the entry position, that is to say in the pressing position, by means which are not shown here, for example by latching of the mandrel holder 39 on the guide shaft 38. The latching action is automatically released in working station 6 for the male mould portion 12 to move out of the female mould portion 14 and for the male mould portion 12 to pivot into the horizontal position.

Figure 3 is a view on an enlarged scale, as a detail from Figure 2, of the extruder 15 (material-supplying device) and the mould 14, the latter being designed for carrying out the method according to the invention. The drawing shows a blank 45 which was formed by the material-supplying device 15. The blank 45 is of a generally lens-like shape in profile. That shape is achievE-i by control of the closure body 46 with a constant pressure in respect of the material flow 49 (plasticised plastic material) in the direction A. When the closure body 46 is closed against the end 47 of the tube 48, the blank 45 is separated from the material flow 49, in particular being squeezed off same. If, when using certain plastic materials, cooling over a large area of the blank 45 on the auxiliary carrier 50 is to be avoided, a blank 45 of a lens-shaped profile is preferred because its support or contact surface is relatively small. However the blank 45 can also be of a hose-like or tubular configuration, for example if cooling of the blank 45 on the auxiliary carrier 50 does not play an essential part.

,1 9 0 0 A simplification is achieved in that case by virtue of the fact that, when the blank 45 is of that configuration, the control of the closure body, which is necessary to produce the blank 45, can be omitted. Annular blanks 45 (of a hose-like, tubular and lens-shaped profile) are also preferred in order for the blanks to be deposited on the auxiliary carrier 50in a position of centrally surrounding the sprung mould pin 51. The mould pin 51 is centrally arranged on the auxiliary carrier 50 and is displaceable against an axial spring pressure in the auxiliary carrier 50 and in the auxiliary carrier bar or rod 52. During the shaping procedure, the mould pin 51 is displaced into the auxiliary carrier 50 by the projection portion 21 which, as part of the mandrel 12, forms a discharge opening of a tube head 17. The delivery end of the material-supplying device 15 is surrounded by an annular nozzle 53 which directs a gas flow 54 on to the blank 45 and/or on to the location of separation between the material-supplying device 15 and the blank 45. According to the invention the temperature of the gas flo' 54 is adjustable sd.that the temperature of the blank 45, while it is being produced and deposited on the auxiliary carrier 50, can be lowered, kept the same or increased, depending on the respective requirements involved in the following pressing operation and for matching of the processing temperatures of the materials constituting the tube head and the tube body portion. With a predetermined amount of gas per unit of tine, the gas flow can be adjusted to flow continuously or intermittently, in the latter case for example only during the period in which the blank 45 is being formed. The gas flow 54, preferably a flow of air, can also be used to facilitate separation of a blank 45 from the material-supplying device 15 if certain plastic materials, in a plasticised state, have a tendency to stick to the closure body 46 or the tube end 47. When the gas flow 54 flows continuously, it can be temporarily increased in a spasmodic or pulsating manner in regard to pressure and/or flow quantity, in order further to assist with i r r r separation of the blank 45 from the material-supplying device. With a discontinuous flow, the gas flow can be increased at the end of a flow period. If there is no need to influence the temperature or the thermal content of a blank 45, a gas flow can be discharged from the annular nozzle 53 for separation purposes only.

The mould 14 includes a shaping portion and a non-shaping portion.

The shaping portion is formed by a part of the end face 60 of the auxiliary carrier 50, the internal contour 61 of the mould jaw portions 62 (the drawing shows two, but in actual fact there are three mould jaw portions 62 which each carry the internal contour 61 formed thereon at their front ends, over a respective division of 120°), and the shoulder mould cavity 63. Adjoining the shoulder mould cavity 63 is a round receiving cavity 64 into which the mandrel 12 with tube body portion 13 passes; during the operation of shaping a tube head 17, at the transition from the shoulder mould cavity 63 to the receiving cavity 64, fusing of the tube body portion 13 to the tube head 17 takes place.

Reference numeral 65 identifies so-called relief configurations which serve to make it easier for the mandrel 12 with tube body portion 13 to be introduced into the mould 14, but which are not :involved in the actual moulding operation itself. The lower end of the mould 14 is formed by an insert 66 with a recess 67. The insert 66 serves to guide the auxiliary carrier 50 with auxiliary carrier rod or bar 52. The recess 67 is of such a configuration that in the lowermost entry position, the auxiliary carrier 50 can be completely Saccommodated ii; the recess 67, the auxiliary carrier 50 being shown *I in the upper outwardly displaced position. In the lowermost entry position, the end face 60 then forms the mould bottom. The mould jaw portions 62 are displaceable radially in the direction B to such an extent that in the open position of the mould jaw portions 62, the auxiliary carrier 50 can pass through the cavity 68 formed by the mould jaw portions 62 having been moved apart, the cavity 68 forming

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iii 11 the discharge portion of a tube, with an external screwthread. Radial displacement of the mould jaw portions 62 also serves to provide that, after shaping of the head 17 with discharge portion, the external screwthread on the discharge portion is brought out of engagemen ,vith the shaping screwthread configuration on the mould jaw portions 62 (that disengagement is referred to as mould release), so that between the working stations 5 and 6, the mandrel 12 with the tube body portion 13 and the tube head 17 moulded thereon can be moved out of the mould 14 and pivoted into a horizontal position. The head machine 10 for carrying out the method according to the invention includes a drive 70 which acts on the auxiliary carrier.

The drive 70 is diagrammatically shown in Figure 3 and it co-operates with the auxiliary carrier rod or bar 52 in such a way that at its front free end, the auxiliary carrier rod or bar 52 with auxiliary carrier 50 passes through the mould 14 along its vertically extending longitudinal axis, that is to say concentrically. The drive 70 can be of mechani r nature (control projections or cams with control St discs), electrical, hydraulic or pneumatic, but the essential consideration is that the speeds of displacement of the auxiliary carrier 50, directed upwardly and downwardly, can be variably set with a drive 70 of the specified kind. It is also within the framework of variable adjustment of the speed of the auxiliary carrier 50 in regard to inward and outward movement thereof to be ,able to set different speeds in one direction. Plasticised plastic materials can be processed for example only when a blank 45 is conveyed from the extruder 15 directly on to the auxiliary carrier

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t and, during the conveying operation, the auxiliary carrier 50 is L moved into the mould, at a speed corresponding to the speed of discharge of the plasticised plastic material out of the extruder until the blank 45 has reached its predetermined weight or volume, in order then to be separated from the extruder 15 and moved into the mould 14 at a higher or lower speed than the removal speed, that is 12 say the speed of conveying imvmnt from the extruder 15 into the mould 14 (depending on the respective nature of the plastic material to be processed), by means of the auxiliary carrier 50. In addition the drive 70 is to be of such a design configuration that, in regard to the distance of outward travel mrovement of the auxiliary carrier between its condition of being completely moved into the recess 67 and the comnpletion of outward movement (the condition in which the end face 60 bears against the closure body 46), the auxiliary carrier is adapted to be stopped at any travel distance therebetween. In regard to the temperature treatment of the plastic material between extrusion and pressing, the method according to the invention is also supplemented by a step in which the blank 45 is heated or cooled between those ty~ production steps. For that purpose, the auxiliary carrier 50 is designed to be heated or cooled by means (not shown).

The method according to the invention, which takes place in the above-described apparatus in %urking station 2, is as follows: In working station 2 the mould 14 is moved into position under the extruder 15. Plasticised plastic material issues from the extruder in the form of an annular blank 45 of for example a lens-shaped profile. While it is issuing, the plastic material issuing from the extruder can be further heated or cooled by means of the gas flow 54.

If the temperature of the blank 45 is not to be influenced, the gas flow 54 can flow continuously at the temperature of the plastic material issuing from the extruder, or the gas flow 54 can be switched off. If plastic materials have a tendency to stick after closure of the closure body 46 (that is to say upon separation of the blank), the separation effect can be assisted by a gas jet or thrust 54 in the illustrated direction. The material-supplying device conveys plasticised plastic material on to the auxiliary carrier Depending on the thermal processing conditions the extruder 15 can now convey a blank directedly on to the auxiliary carrier 50 in order then to be moved into the would 14 for the pressing operation, at a r1 13 predetermined speed. It is also possible in accordance with the invention for the auxiliary carrier 50 to cover for example only half the travel distance between the lowermost entered position and the uppermost extended position, and to stop there, to cause the blank 45 to drop on to it in a condition of free fall after the blank has been separated from the extruder, in order then, that is to say after the blank 45 has dropped on to the auxiliary carrier, to move the auxiliary carrier into the mould at a predetermined speed. In that operation the speed of inward movement of the auxiliary carrier can be greater than, equal to or less than the speed of downward movement as between the extruder 15 and the auxiliary carrier After the auxiliary carrier 50 has moved into the mould, :hat is to say after it has been completely received in the recess 67 and its end face 60 forms the bottom of the mould, the mould jaw portions 62 move in the direction C, closing the jaw cavity 68, towards the centre. The loaded mould is now ready for the operation of forming the tube head by means of the mandrel 12. By virtue of adjustability of the speed of downward movement and the length of the downward a travel movement (between zero, that is to say the auxiliary carrier 50 remains inactive in the recess 67, and the uppermost extended position, that is to say the position in which the auxiliary carrier initially takes a blank 45 directly from the extruder 15), the invention provides a method for the production of tube heads which can be adapted to a large number of thermal processing requirements of plasticisable plastic materials. The adaptability aspect is enhanced by virtue of the fact that, by adjustment of the temperature of the gas flow 54 and/or temperature adjustment of the auxiliary carrier •50, it is possible to exert an influence on the thermal content of the blank 45 before it is moved into the mould 14 and subjected to the pressing effect.

Claims

1. A method of filling a mould for moulding a tube head of plastic material, on an open end of a tubular body portion of a tube, wherein a portion of material is separated, as a blank, from a vertically downwardly directed flow of plasticised plastic material, introduced into a mould cavity of a mould, and then pressed by means of a mandrel with a tube body portion carried thereon, to provide a tube head which is connected to the tube body portion, characterised in that: the portion of material is received by an auxiliary carrier which is displaceable between the material-supplying device and the bottom of the mould cavity, and the portion of material is introduced into the mould cavity at controlled speeds which can be equal to, greater than or less than the speed of a free fall of the portion of material.

2. A method according to claim 1 characterised in that the portion Sof material is put directly on to the auxiliary carrier.

3. A method according to claim 2 characterised in that the auxiliary carrier is moved into the mould at a speed which corresponds to the conveying speed of a material-supplying device. o

4. A method according to claim 1 characterised in that the blank is put on to an auxiliary carrier which is disposed at a spacing relative to the mould.

A rm :hod according to claim 4 characterised in that the blank is put on to the auxiliary carrier by falling on to same.

6. A method according to one of claims 1 to 5 characterised in that the blank is introduced into the mould at an accelerated or decelerated rate from a starting speed. H:\susan\keep\speci\77448-94-NGM.1.DOC 29/06/98

7. A method according to one of claims 1 to 6 characterised in that the blank is of a lens-shaped configuration in profile.

8. A method according to one of claims 1 to 6 characterised in that the blank is of a tubular configuration.

9. A method according to one of claims 1 to 8 characterised in that, during the shaping operation, by means of a gas jet the blank is either heated, held at the same temperature as the discharge temperature of the plasticised plastic material or cooled down.

A method according to one of claims 1 to 9 characterised in that the blank can be pushed away from the material-supplying device by means of a gas jet. a

11. A method according to one of claims 1 to 10 characterised in t that the blank is heated or cooled by means of the auxiliary carrier. (tt Dated this 29th day of June 1998 KMK LIZENCE LTD By their Patent Attorneys GRIFFITH HACK SFellows Institute of Patent Attorneys of Australia I .t r i I- ili-~*4s* ABSTRACT The invention concerns a method of filling a mould for moulding a tube head on a tubular body portion of a tube. A filling procedure is known in which the filling time is invariable. The constant filling time sets limits in regard to the use of certain 'high-tech' plastic materials, and that is found to be a disadvantage. The method according to the invention provides variable filling times, whereby that disadvantage is overcome. a Sa a Ct a.. (a It C -I I r ji