CA2042600A1

CA2042600A1 - Process and device plus winder core for the production of pipe fittings made of fibre-reinforced plastic

Info

Publication number: CA2042600A1
Application number: CA002042600A
Authority: CA
Inventors: Norbert Lona
Original assignee: Individual
Current assignee: ARUNDO TECHNOLOGY AG
Priority date: 1989-10-04
Filing date: 1990-10-04
Publication date: 1991-04-05
Also published as: HUT59870A; AU6400490A; ATE121006T1; EP0463122B1; NO912104D0; EP0463122A1; HU907615D0; WO1991004843A3; ES2073584T3; FI912657A0; DK0463122T3; AU636394B2; WO1991004843A2; NO912104L; DE59008906D1

Abstract

A b s t r a c t An inner gel coat is poured around a core (11) which is separable into several pieces. The inner gel coat is cured by heating. The core (11) is clamped to the head (39) of a robot (49). A glass fibre web (46) impregnated with liquid plastic is wound in an overlap-ping manner in several layers around the inner gel coat in a winding station (38). The plastic of the fibre web (46) is cured by heating and finally an outer gel coat is applied around the layers of fibre web and cured. Sub-sequently the core (11) is removed from the fitting. In this manner, a fitting of high, uniform quality can be economically produced.

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Description

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Process and device and winding core for the production of fittings made from fibre reinforced plastic Fibre reinforced plastic pipes are often joined to one another using glued fittings made from fibre re-inforced plastic. A large number of fittings of this type, for example bends, T-fittings or double junction fittings are usually necessary in pipe installations.
On average there is about one fitting per metre of pipe.
US-Patent 3,963 185 descloses a process and a device for the automatic production of a T-fitting.
A core is mounted to a shaft which is rotatable about its axis, The shaft is mounted to a motor which is mounted on a sled. The sled is displaceable along a circular path such that the core can pivot about an axis perpendicular to the shaft axis. Above the core a table is mounted rotatably about a vertical axis and displaceably vertically. The table bears two suppIy rolls each of glass fibre rowings and - webs. The rowings and webs are led over outlet edges on the lower end of two arms projecting vertically downwards from the table. For producing a fitting first a few windings i ~ ' ! ' ,. ' , .. .

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are wound manually onto the core with the rowings and bands. Subsequently several layers of circumferential windings are wound onto the three sockets of the core, by turning the table. Then on the two aligned sockets rows of short pins are inserted into the wound layers.
The shaft is tilted by 45 relative to the turn table axisO In this position diagonal windings are wound. The pins prevent sidslip of the windings. Subsequently further windings are wound in circumferential direction.
The finished fitting is layed into a mold where flanges are attached to it. The fitting is cured in the mold.
The way of diagonal winding described in ~S-Patent 3,963,185 is not practicable. As a matter of fact only small surface parts of a T-fitting can be wound with such diagonal windings. The proposal according to this patent, therefore, is not used in practice.
The problem to be solved by the present invention is to propose a process, a device and a winding core for the automatic production of fibre reinforced plastic fittings.
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According to one aspect the present invention comprises a process for the production of a fitting made from fibre reinforced plastic for joining hollow profiles, comprising the following steps:
a) a core is fastened to a head of a program con-trolled machine, the head being pivotalbe around ~`
at least two axes and moveable in at least two directions;
b) in a winding station a fibre web is wound in an overlapping manner around the core in several layers;
c) the fibre web is impregnated with liquid plastic;
d) the plastic of the wound fibre web is cured; and e) the core is removed from the fitting.
According to a further aspect the present inven-tion comprises a device for the production of a fitting :~
made from fibre reinforced plastic for joining hollow profiles t the device comprising a program controlled machine with a head for holding and pivoting a core, the head being pivotable about at least two axes and displaceable in at least two directions, and a winding station with a winder containing a feed roll of fibre web which is lead over an outlet edge on an arm of the winder, a drive motor for turning the winder, and a cutting device at the outlet edge for cutting the fibre web.

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According to a th;rd aspect the present invention comprises a ~inding core for the production of a f;tt;ng made from fibre reinforced plastic for joining hollo~ profiles~ in which the core is formed from at least three rigid core p;eces which are joined to each other in a separable manner and an elastomeric hollow body, which surrounds the core pieces and determines the inner shape of the fitting.
Exemplary embodiments of the invent;on are subse-quently expla;ned with reference to the drawings. In the drawings:
F;g. 1 shows the product;on of a core, Fig. 2 the pour;ng on of an ;nner gel coat, F;g. 3 an ax;al sect;on through a wind;ng station, ~ -~
Fig. 4 a plan v;e~ of the stat;on shown in Fig. 3, f;g. S a sect;on ~hrough an impregnat;on station, F;g. 6 a detaiL of the fibre web outLet from the winding station, F;g~ 7 a schematic represeneation of a patch laying station, Fig. 8 the production of the outer gel coat, and Fig. 9 a core for the production of bend pipe fitt;ngs.
Fig. 1 sho~s the production of a hollo~ body 10 as a component of a core 11. The core 11 comprises three rigid~ for example metal~ core pieces 12, 13, 14 which can be ioined together, and de~ermines the inner shape of a ~-fitting wh;ch is to be produced. Each of the core p;eces 12, 13, 14 has a cylindr;cal shoulder 15, wh;ch determ;nes the inner shape o~ the correspond;ng adhes;on sockets of the fittings, and a clamping section 16 con-nected e~ternalLy to the shoulder 15. The shoulders 15 at least, are coated ~ith an ant;-adhes;on covering, for example with PTFE. The three core pieces 12, 13, 14 are assembled ;n a casting mould 17 in such a ~ay that the cylindrical shoulders 15 are each centred ;n a cylindrical - . . ~: ,- , ,. ; ,. .
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bore 18. The inner shape of the casting moul~ 'c~res-ponds to the inner shape of the T-fitting which is to be produced. In the case of the core piece 12 a section 19 which tapers conically towards the free end is joined to the cylindrical shoulder 15, the tapering section 19 having a coaxial centreing cone 20 at the free end and an axial threaded hole 21. The section 19 has, in the middle, a cylindrical recess 22 running transversely and having a central threaded hole 23. In the assembled state, a cylindrical shoulder 24 at the free end of the core piece 14 is centred in the recess 22. 8etween the cylindrical shoulders 15, 24, the core piece 14 has a conically tapering section 25. The core piece 13 is centred on the conical piece 12 by means of a conical recess 26 which is coaxial ~ith the centreing cone 20.
The three core pieces 12, 13, 14 are clamped ;n the casting mould 17 by screws 27. Now the hollow space surrounding the conical sections 19, 25 is filled with a liquid silicon rubber material. After this material has set, the screws 27 are loosened and the core pieces 12, 13, 14 are removed from the casting mould 17, it being pos-sible to blow in compressed air to facilitate demoulding.
The hollow body 10 is also expediently released and removed from the casting mould 17 using compressed air.
Subsequently, the core 11, comprising the core pieces 12, 13, 14 and the hollow body 10 is reassembled.
In order to produce an adhesion fitting, the core 11 is initially inserted into a two-part casting mould 33 as in Fig. 2, and centred using the three cylindrical shoulders 15 in flush-f;tted cylindrical bores 32. The casting mould 31 surrounds the hollo~ body 10 on all sides with some play. A liquid ;nner gel coat, for example a thermoset having a high proportion of plasti-cizer is poured into this intermediate space between cast;ng mould 31 and hollow body 10. In the finished fitting the inner gel coat forms a resin layer containing few fibres des;gned to ;mprove corros;on resistance. In order to cure the ;nner gel coat 33 wh;ch has been formed ;n this way, the cast;ng mould ;s heated, for example by -~.

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running hot water through a coiled pipe 34 built into the casting mould 31. After curing of the inner gel coat 33 the casting mould 31 is cooled for example with cold water the casting mould 31 is opened and the core 11 with the inner gel coat 33 is removed. The inner gel coat extends only between the cylindrical axial shoulders 15 and only over the hollow body 10. The adhesion sockets which are formed later around the shoulders 15 thus have no inner gel coat.
The core 11 is now clamped in a winding station 38 to the head 39 of a six- axes robot 40 by the clamping section 16 of the core piece 14. The core 11 can be swivelled to and fro by the robot 40 between a winder 41 (Fig. 3 and 4) and a patch laying station (Fig. 7). The winder 41 shown in Fig. 3 and Fig. 4 is mounted on bearings to rotate about a vertical axis on a vertical pipe-shaped stand 42 and is rotated by a servo motor 43.
A feed roll 45 with for example a woven glass fibre web 4b is mounted on a verticaL trunnion 47 on a hori~ontal plate 44 which turns in unison. The ~eb 46 is led ~hrough a pair of rolls 48 a photo-electric barrier 49 a compression roll 50 and several deflection rolls 51 to an impregnation station 52. A back-up roll 45a with back-up web 46a is mounted next to the feed roll 45 on a second trunnion 47a. The back-up web 46a is led through a second pair of rolls 48a and a second photo-electric barrier 49a and the end of the web is fastened in an easily detach-able manner to a further compression roll SOa. A double-sided unsupported adhesive strip is attached to the end of the web 46a facing the fibre web 46. The compression roll 50a is mounted on a tiltable plate 53 and can be pres-sed asainst the roll 50 by ~eans of a ~neumat;c cylinder 54. This occurs when the end of the fibre web 4b is signalled by the photo-electric barrier 49. The beginning of the back-up web 46a is thus automatically attached to the end of the web 46. The replacement of the empty spool may awai~ the winder 41 coming to a stop.
The fibre web 46 passes round two fixed cylinders 58 in the impregnation station 52. These each have an . : ~, .
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axial elongated slot 60 in their cylinder wall 59u The elongated slot 60 is partly covered above and below in each case by a shackle 61, 62, so that its length can be adjusted exactly to the width of the fibre web 46~ A
bore 63 in the cylinder 58~ in communication with the elongated slot 60, is connected by a hose 64 with a central feed pipe 65 for liquid plastic, for example a liquid thermoset. The fibre web 46 covers the elongated slot 60 of both cylinders and is impregnated by these with liquid plastic from both sides.
The impregnated web is led from the impregnat;on station over two deflection rods 69 inclined at 45 attached to an arm 70 which projects vertically from the plate 44, and is deflected by 90 in each case, so that it is led rad;ally inwards over an outlet edge 72, along a radial inwardly projectins, upper end section 71 bent at right angles. A web brake, formed by two parallel rods 74 rigidly fastened to a plate 73 is fitted to the arm 70 between the deflection rods 69. The plate 73 is tiltable parallel to the axis of the rods 74, and lockable, so that the braking effect can be adjusted.
The outlet edge 72 is formed on a prismatic body 77 made from plastic. The material of the body 77 is selected so that the body 77 is not wetted by the liquid ZS plastic of the fibre web 46. An arm 79 can be swivelled by a motor 80 about an axis 78 arranged paraLlel to the out~et edge 7Z. The ar~ 79 has a knife 81 attached to ;ts free end. Upon actuation of the motor 80 the knife 81 strikes against the body 77 and cu~s through the ~eb 46. Here, the end of the web remains attached to the body 77 in an easily detachable manner. In order to attach the end of th;s band to the core 11 at the beginning of a ne~ winding operation or to a previous wound layer~ two heating elements 82 are arranged in the body 77 near the outlet edge 72 (Fig. 6). The plastic in the fibre web 46 can be rapidly heated to the temperature required for curing at spot locations over the heating elements 82. The heating elements 82 are arranged on a surface 83 adjoining the outlet edge 72 inclined to -.., ., I

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the plane of the fibre web 46 drawn from the upper deflection rod 69. Further heating elements 82a can be arranged at the ather surface 84 adjoining the outlet edge 72, in order aLso to attach the ends of the winding to this winding.
In operation~ the core 11 is initially brought against the surface 83 by the robot 40 in such a way that the inner gel coat ;s pressed against the end of the fibre web 46 at the position of the heating elements 82 (position A in Fig. 4)~ The liquid plastic of the fibre web is cured at point locations at this position by switching on the heating elements 82 and in this way the end of the web is fixed to the inner gel coat. During the subsequent ~inding, the winder 41 is turned under program control by the servo motor 43 and the core 11 is at the same time displaced and canted by the robot 40 in such a way that a layer oS overlapping fibre web is wound onto the gel coat 33 and the three sections 150 Here, the first movement of the robot is directed radially into the centre towards the axis of rotation of the winder 41. When one layer has been wound, the core 11 held by the head 39 of the robot 40 is again brought against the outlet edge 72, but th;s time in the position B in Fig~ 4. No~ the knife 81 is caused to strike against the outlet edge 72 by actuat-on of the motor 80, so that the fibre web 46 is cut through. The end of the web can be fixed to the wound layer by switching on the heating ele~ents 82a.
When winding bifurcated fittings such as the T-fitting sho~n, a triangular sur~ace ~;thout fibre webwinding remains in each case on either side of the bifurcation. After each winding, a patch 89 of glass fibre fabric is laid in these places in the pa~ch laying `
station 88 (Fig. 7). The patch laying station 88 has a feed roll 90. From this, a web of glass fibre fabric 92 is intermittently dra~n through a storage loop 91 by means of a pair of rolls 93. The web 92 is cut to r;ght angled patches 89 in a cutting station 94. These are gripped and lifted by means of an arm 95 which can be ,:

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swivelled and has a suction plate 96 attached to it. The core 11 is held out horizontally within the swivelling -range of the arm 95 by means of the head 39 of the robot 40. A second swivelling arm 98 carries a pad 99, which can be immersed in a flat container 100 of liquid plastic. The arm 98 is subsequently swivelled, so that the pad arrives above the position on the core 11 which is not wound with the glass fibre web 46. This position is wetted with liquid plastic by sinking of the arm 98.
Subsequently the patch 89 which has been sucked up by the plate 96 is swivelled by the arm 95 above the core 11 and lowered onto the wetted position. The patch 89 which has been laid on is fastened to the layer of fabric using four heating elements 97. Now the core 11 is turned through 180 by the head 39 and a second patch 89 is applied in the same manner to the opposite side.
In this manner, windings of glass fibre web 46 and patches 89 are alternately laid on the core 11 until the required thickness of material is reached. Since the movements of the robot 40 and of the winder 41 can be programmed in an exactly reproducible manner, a great~
uniformity of the strength properties of the fittings produced i5 achieved.
As can be seen from the drawings, the robot 40 has at least four degrees of freedom: The head 39 must be pi~otable around two mutually orthogonal axes and moveable parallel to the axis of rotation of the winder 41 and in at least one direction radial thereto. In order to reach the patch laying station 88, the head 39 in the embodiment shown is moveable in two radial direc-tions. In the exemplary embodiment shown in Fig. 3 these five degrees of freedom are realized by five swivel axes A1 through A5.
When the fittings have been finally wound, the robot places them, by one of the exposed clamping sec- ;
tions 16 onto a conveyor belt, which carries them through a continuous oven in order to cure the plastic. After ,.

curing of the plastic the core 11 is removed from the fitting by loosening the screws 27, and the core pieces 12, 13r 14 are pulled apart in their axial direction.
Finally, the elastomeric hollow body lO is removed from the fitting. This hollow body 10 is reusable several times.
In order to protect the external surface of the fitting 105 obtained in this way, the fitting is subse-quently clamped into a two-part casting mould 106 (Fig.
8). In the mould, the fitting 105 is centred by the three moulded-on adhesion sockets 107 each to one cone 108 of a plug 109. A flange 110 is formed on each plug 109. The flange is clamped by screws 111 against the mould 106.
The casting mould 106 has coiled pipes 112 for heating and cooling. The intermediate space between the casting mould 106 and the centred fitting 105 within it is now filled with a liquid outer gel coat 113. The outer gel coat 113 is hardened by heating up the mould 106. Finally, ~ `
the casting mould 106 is opened and the finished T-fitting 105 is removed from the mould.
The proc~ss described is also suitable for simpler -fittings for example the bend pipe fitting 115 shown in Fig~ 9. Here, the core comprises two core pieces 116, 117, to each of which is screwed a cy]indrical shoulder 118 for forming the adhesion sockets with a clamping section 119 for gripping using the xobot. Both core pieces 116, 117 ha~e a slightly tapering cross section towards the free end of their torus-li]ce sections. Demoulding is thus facilitated~ They are centred on one another by means of two centreing cones 120, which locate in conical recesses 121 and can be clamped together by screws 122.
Both shoulders 118 are fastened by additional screws 122 to the core pieces 116, 117 and in each case are centred by at least one other centreing cone 120 against the core pieces 116, 117. The core pieces 116, 117 are surrounded by a quarter-circle shaped silicon rubber tube 124/ which again extends only between the shoulders 118 and facilit-ates the demoulding of the core pieces 116, 117. In order , .

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to additionally facilitate demoulding, the core pieces 116, 117 have bores 123 for connecting compressed air. The bend pipe fitting 115 is constructed in a similar manner to the pxeviously described T-fitting 105, except that here no patches are laid between the individual winding layers.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A proces for the production of a fitting made from fibre reinforced plastic for joining hollow profiles, comprising the following steps:
a) a core (11) is fastened to a head (39) of a program con-trolled machine (40), the head being pivotable around at least two axes and moveable in at least two directions;
b) in a winding station (38) a fibre web (46) is wound in an overlapping manner around the core (11) in several layers;
c) the fibre web (46) is impregnated with liquid plastic;
d) the plastic of the wound fibre web (46) is cured; and e) the core (11) is removed from the fitting.

2. Process according to Claim 1, in which an inner gel coat (33) is applied and cured before winding the fibre web (46) around the core (11).

3. The process according to Claim 1, in which the fibre web (46) is impregnated with liquid synthetic resin before being wound up.

4. The process according to Claim 1 for the produc-tion of a bifurccated fitting, in which patches (89) made from fibre mats are laid at the bifurccations of the fitting between the layers of the fibre web (46).

5. The process according to Claim 4, in which in each case the beginning of the fibre web (46) is attached to a layer by local curing of the plastic in point loca-tions.

6. A device for the production of a fitting made from fibre reinforced plastic for joining hollow profiles, the device comprising a program controlled machine (40) with a head (39) for holding and pivoting a core (11), the head being pivoteable about at least two axes (A4,A5) and displaceable in at least two directions, and a winding station (38) with a winder (41) rotateable about its axis and containing a feed roll (45) of fibre web (46), which is led over an outlet edge (72) on an arm (70) of the winder (41), a drive motor (43) for turning the winder (41), and a cutting device (78-81) at the outlet edge (72) for cutting the fibre web (46).

7. The device according to claim 6, in which an impregnation device (52) for impregnating the fibre web (46) is arranged in the winder (41) between the feed roll (45) and the outlet edge (72).

8. The device according to claim 6, in which elements (82) for curing the plastic of the fibre web, (46) in point locations are arranged on the winder (41) near the outlet edge (72) in order to attach the beginning of the fibre web to an inner gel coat (33) or a previous wound layer on the core (11).

9. The device according to claim 6, in which a patch laying station (88) is arranged next to the winding station (38) for applying patches (89) made from fibre mat between successive windings of fibre web (46), on the places which remain exposed when winding.

10. A winding core for the production of a fitting made from fibre reinforced plastic for joining hollow pro-files, in which the core (11) is formed from at least three rigid core pieces (12,13,14) which are joined to each other in a separable manner, and an elastomeric hollow body (10) which surrounds the core pieces (12,13,14) and which de-termines the inner shape of the fitting.