CA2051220C - Pultruded profiles - Google Patents

Abstract

Pultruded profiles are manufactured at a die station (8) which is fed with resin via a pump (27). The core of the profile is formed by granular material fed to station (8) from a hopper 10 through the interior of a hollow duct (13) which is essentially vertically disposed, above the station (8), so that the granular material is moYed under the influence of gravity. The exterior surface of duct (13) is profiled and the skin forming materials (9,9A) for the profile are guided by the profiled surface to the die station (8). The skin forming materials ara runs of cloth. The pultruded profile may be tubular or hollow so that it has both an external surface and an internal surface in which case the internal surface incorporates a further resin bonded cloth fed to the interior of the die station over the external surface of a mandrel.

Description

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PULTRUDED PP~OFILES
This invention relates to in~line core-filled pultruded profiles.
One form of pultruder for the manu~actur2 of in-line core-filled pultruded profiles is known from International Patent Specification No W088/08367 which -discloses an arrangement in which the dry materials are fed along a generally horizontal path to a pultrusion ~ die where a bonding resin is injected in a manner which effects complete resin wet through so that the resultant product which emerges from the die has excellent filler bonding and surface finish. The dry materials comprise particulate core filling materials (such as silicate hollow spheres, vermiculite and many moxe and of varying relatively light weights) which are borne along the hori~ontal path by an air stream generated by a variable output Venturi blower. The pal:h extends through the interior o~ a duct which tapers along its length and externally is shaped progressively to con~orm to the cross~sectional shape of the die. The exterior surface O~ the duct acts as a guide for runs of dry cloth which are fed to the die to provide a cloth skin as an integral part of the resultant pultrusion~
It is an object o~ the present invention to provide a new and improved system of manu~ac~uring pultruded profiles having a skin rasin-bonded to a core.
According to the present invention there is provided . ;;

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~ system o~ manufacturing pultruded profiles having a skin resin-bonded to a core, comprising separately fee~; ng core~forming materials and a skin-forming cloth to the inlet of a pultrusion die station which include.
5 a resin~curing die having a cross-sectional shape ~or determ;ning the cross-sectional shape of the profile, the core~forming materials being delivered to the die station inlet through the interior of a hollow duct and the skin-forminy cloth bei~g delivered over the external surface of the duct to the die station inlet7 introducing bonding resin to said station, and pulling ~rom the outlet of said station an in-line cored resin-bonded profile, characterised in that the hollow duct is essentially vertically disposed and the core-filling materials are moved through the duct under the influence o~ gravity to the die station.
3y virtue of the present invention the core-filling materials are not propelled by an air stream so that the apparatus is simpler than hitherto by the absence o~ a variable output Venturi blower and the vertical disposition o~ th~ duct with gravity feed of the core filling materials renders the system insensitive to the specific weight of these materials. Accordingly a much wider weight range of such materials can now be used.
Furthermore it i~ comparatively easy to achieve an even distribution of these materials across the cross-sectional area of the profile. This may be ~ .. ~...
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arhieved, for example~ by means of a vibratory screen at the top of the duct.
The pxesent invention also provides a system of manufacturing tubular pultruded profiles having intexnal and external skins resin-bonded to a core, comprising separately fee~ing core-fo~ming materials and skin-forming cloths along substantially vertical pathways to the inlet of a pultrusion die station which includes a resin-curing die having a cross-sectional shape ~or deteL ; ni ng the external cross-sectional shape of the profile and a vertically-disposed mandrel having a cross-sectional shape for determining the internal cross-sectional shape of the profile, the external skin-forming cloth being delivered to the die station 1 inlet over the external surface of a vertically-disposed hollow duct which surrounds the mandrel, the internal skin-forming cloth being delivered to the die station inlet over the external surface of the mandrel, and the core-~orming materials being deli~ered under the influence o~ gravity to the die station inlet through the annular space betwe~n the duct and the internal skin-forming cloth.
It will be appreciated that the manufacture of tubular pultruded profiles is rendered practical by the absence of an air stream to carry the core forming :~
materials and this in turn is rendered practical by gravity feed of ~he core-~illing materials through a .

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vertically disposed duct.
The sXin-forming cloth material is generally as described in W088/08367 and the core-forming materials may also be as therein described but additionally may be of substantially heavier weights. Likewise, the duct and pultrusion die is substantially as previously described in W088/08367.
Embodiments of the present invention will now be describ~d by way of example with reference to the 10 accompanying drawings, in which -Fig 1 is a schematic illustration of a sys em of manufacturing pultruded profiles in accordance with the present invention;
Figs 2A and2B lllustrate alternative profiles which can be produced by the system of Fig 1;
Fig 3 illustrates a modi~ication of the Fig 1 system ~:
that is adapted to produce tubular profiles;
Fig 4 schematically illustrates a detail of the Fig :

3 system, and Fig 5 illustrates a profile which can ~e produced by the system of Fig 3.
In the system of manu~acturing pultruded profiles w~ich is shown in Fig 1 cloth, preferably woven fibreglass 14,14A, is delivered by supply rolls 9, 9A
and guided over the external profiled surface of a former duct 13 to a pre-die former 15, throuyh the dies 16, 17, 18, of a die station 8 to clo~h pulling rolls . .

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1~. The duct 13 i5 hollow, i5 vertically orientated, and at its end 11 remote from the former 15 there is delivered particulate core filling material, from a hopper 10 incorporating a vibratory screen 12. The 5 particulate core filling material is fed under the influence of gravity towards the di~ station 8 and forms a body o~ core filling material filling the space between the runs of cloth 14, 14A, in the gap 21 between the pra-die former 15 and the leading die section 16 of station 8. The cloth runs 14, 14A, when sec~xed to the start rolls 19 are fashioned to occupy the contours o~
the dies in station 8 and are held in this configuration through the pre~die former 15 and over part of the exterior surface of the duct 13 which is elongate and is provided with an external shape. which progressi~ely along its length conforms to the cross sectional shape o~ the resin curing die 18 and at the die station end of the duct 13 is similar in cross section but oversize in relation to that of the resin curing die 18. The cloth 14, 14A, is held under slight longitu~i~Al tension ~y a combination of the effect of supply rolls 9, 9A, and rolls 19. When the start or taXe up rolls 19 are set in motion and cloth 14, 14A, is pulled, the cloth with its care forming materials (initially held in place by a shaped pl~g (not shown) ~itted into the space between the cloth runs 14, 14A in gap 21~ progresses throu~h the die station 8 which i5 supplied with resin fed to .

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injection die 17 via a pump 27. The emergent pro~ile 28 which is resin cured is collected by retractable pullers 26 which progress the profile and permit the cloth rolls 19 to be separated ~ince they no longer function when the cloth 14, 14A, has been resin bonded. Curing die 18 is progra~med to function at the appropriate temperature for curing the resinO
The pre-die former 15 which at its outlet end is of ~:
~ n~ion slightly in excess of the curing die 18 i~
located in proximity to but spaced from the bell mouth entry of the leading or for~ing die section 16, the precise spacing 21 being determined to permit the cloth 14, 14A, to form completely and move without distorting with core material in the gap or space 21 in the form of 1 a slightly raised moving wall which completely occupies the hollow profile shape and is encased between the two runs of cloth 14, 14A which overlap along their longitudinal edges thus preventing discharge of fill~r material. :
The interior surface of the duct 13 may also conform progressively along its length to the cross-sectional shape of the die 18 and at the die s~a~ion end is similar in cross-s0ction to tha~ of ~he die 18 so that the core-forming materials progressively conform to the cross-sectional shape o~ the die 18 as they approach the die station.
Figs 2A and 2B illustrate alternative profiles 28 :. ..; . ~ : : !
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which can be produced by the Fig 1 system from which it will be appreciated that simple or complex cross-sectional shapes are possible and in each instance the corP is solid~ However because duct 13 is vertically oriented the sp~r; f; c weight of the core is not limited and virtually any weight of particulate core ~illing materials may be ~sed and which are capable o~
being evenly ~i~tr;huted ~rQ~ the core cross section by the vibLdLu~ s~r~
Figs 3 and 4 illus~rate a modified version of the Fig 1 system in which a r~n~rPl 30 travPrses the length of the hopper lO, the duct .13 and the die station 8 in order to enable tubular pro~iles such as profile 31 of Fig 5 ta be ~anufactured. For this purpose in addition to cloth supply rolls 9,'9A there are provided cloth supply rolls 32, 32A which provide cloth runs 33, 33A
guided into die station 8 over t:he external surface of the mandrel 30 so that the~e ru~ls 33, 33A form the - internàl skin 34 of the profile 31. The mandrel 30 is secured at its upper end to a support structure (not shown) and initially i5 centred a~ its lower end in the die 8 by the starting plug (not shown). However when -t~e system is in ,;ormal operation, having progressed beyond its start-up phase, tha lower end of the mandrel is essentially self cer.tred by the annular body of core filling materials p_-ovided from the hopper 10 between the interior surf,ce of the duct ~3 and the exterior ~, ,., ::
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surface of the cloth-covered mandrel 30 which at and beyond the die station are substantially solid.
Vibratory screen 12 in the Fig 3 system is annular and in both systems contributes to exact placement and ;' good packing of the particulate matter in the profile 28, 31 without signiflcant restriction on granular size or weight. :

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Claims (3)

1. A method of manufacturing pultruded profiles having a skin resin-bonded to a core, comprises separately feeding core forming materials and a skin-forming cloth to the inlet of a pultrusion die station which includes a resin-curing die having a cross-sectional shape for determining the cross-sectional shape of the profile, the core-forming materials being delivered to the die station inlet through the interior of a hollow duct and the skin-forming cloth beins delivered over the external surface of the duct to the die station inlet, introducing bonding resin to said station, and pulling from the outlet of said station an in-line cored resin-bonded profile, characterised in that the hollow duct is essentialiy vertically disposed above the die station and the core-filling materials are moved through the duct under the influence of gravity to the die station.

2. A method as claimed in claim 1, wherein an even distribution of the core-filling materials across the crass-sectional area of the profile is achieved by vibrating a vibratory screen at the top of the duct.

3. A method of manufacturing tubular pultruded profiles having internal and external skins resin-bonded to a core, comprises separately feeding core-forming materials and skin-forming cloths along substantially vertical pathways to the inlet of a pultrusion die station which includes a resin-curing die having a cross-sectional shape for determining the external cross-sectional shape of the profile and a vertically-disposed mandrel having a cross-sectional shape for determining the internal cross-sectional shape of the profile, the external skin-forming cloth being delivered to the die station inlet over the external surface of a vertically-disposed hollow duct which surrounds the mandrel, the internal skin-forming cloth being delivered to the die station inlet over the external surface of the mandrel, and the core-forming materials being delivered under the influence of gravity to the die station inlet through the annular space between the duct and the internal skin-forming cloth.