REINFORCEMENT OF MOULDED CONSTRUCTION PRODUCTS

Abstract: The invention is concerned with a method of and a means for introducing reinforcing strands into a vertical mould (2) through the open upper end thereof. An array of strand material (1) is positioned to extend across the open end of the mould, and an insertion means (3) is lowered into the mould, the insertion means engaging the strand material during its downward motion and drawing an appropriate amount of such material from a continuous supply (5) thereof to give a strand reinforcement of elongate U-shape within the mould. A reciprocable carriage (8) is provided whereby the leading end of the strand is presented to a clamp means (11) at the remote side of the mould opening, the carriage (8) having a selectively operable clamp (10) thereon for engagement with the strand (1) during movement of the carriage (8) towards the clamp means (11).

Description: The invention concerns the reinforcement of moulded construction products, and has more particular reference to the introduction of reinforcing material in the form of strands into a mould intended to receive a fluent, mouldable material. The invention is particularly, though not exclusively, concerned with the inclusion of elongate reinforcing materials in partition panels comprising liquid setting particulate materials such as gypsum. In our prior British Patents Nos. 1346767, 2045150 and 2067125, and in GB-A-2183200, we disclose methods for the production of such construction products as partition panels, roof decking and pipes from liquid setting particulate material, the methods involving the feeding of dry powders or powder/fibre mixes at a controlled rate into moulds containing vertical core formers and the compacting of such powders or powder/fibre mixes by vibration or by a combination of vibration and pressure. The requirement may exist for the reinforcement of the construction product throughout its vertical extent (in the mould) by a continuous elongate material, for example a glass fibre strand. The introduction of the strand, or a plurality thereof, in spaced side-by-side disposition, throughout the considerable vertical extent of a mould for producing storey height partition panels gives rise to difficulty, particularly in view of the need to locate the individual reinforcing elements relative to the surface of the end product to very close tolerances and do this reliably under automated production conditions. The object of the present invention is to provide a method of and means for the introduction of reinforcement into a construction product. According to one aspect of the present invention there is proposed a method for the manufacture of a cored construction product, including the steps of introducing at least one axially reciprocable core former into a vertical mould through an open top thereto, feeding powder or a powder/fibre mix into the mould, compacting the powder or powder/fibre mix and withdrawing the said at least one core former to provide a respective core void or voids, characterised by the preliminary steps of positioning at least one flexible reinforcing strand to overlie the open top of the mould, securing one end of the or each strand against longitudinal movement, providing an elongate strip in parallel relationship to and at that side of the said one strand remote from the said open top and engaging said strip with an insertion means reciprocable into and out of said mould, and progressively moving said insertion means into the mould thus to draw a requisite length of said at least one reinforcing strand into the mould to exist therein in tensioned state and to extend throughout substantially the whole of the vertical extent of the mould. According to a preferred feature, each strand is positioned to extend across the said open top by feeding from a strand supply at one side of the mould and the free end of the strand is clamped at that side of the mould remote from the said supply, the strand moving relative to the insertion means on progressive engagement of said insertion means with the mould. According to a further preferred feature, a plurality of reinforcement strands is introduced simultaneously into the mould, said strands being provided in spaced side-by-side disposition and being engaged by a common insertion means. According to another aspect of the invention, there is proposed apparatus for introducing one or more reinforcing strands into a vertical mould comprising a carriage movable between first and second positions relative to the open top of the mould and respectively corresponding to advanced and retracted positions of the carriage, a first selectively operable strand clamping means on the said carriage to receive a reinforcing strand or strands into engagement therewith, a second selectively operable strand clamping means at that side of the said open top remote from the said carriage likewise to receive the reinforcing strand or strands, said first and second clamping means being actuable to clamp strands engaged therewith, and insertion means in alignment with the open top of the mould, the said insertion means being reciprocable in the plane of the mould and being adapted upon such reciprocation to engage each said reinforcing strand, to draw the same from a supply thereof and to introduce said strand or strands into the mould throughout the whole or substantially the whole of the vertical extent thereof. According to a preferred example, the insertion means is cooperable with an elongate strip extending transversely of and releasably engageable therewith, the elongate strip being positionable to overlie each said reinforcing strand and the insertion means engaging each strand through said strip. According to a further preferred feature, the elongate strip comprises a card profiled for location relative to the insertion means and to position the or each elongate element relative thereto. The invention will now be described further, by way of example only, with reference to the accompanying diagrammatic drawings illustrating two embodiments thereof and in which : - Figs. 1A to 1E show, in diagrammatic manner, the successive stages in the introduction of reinforcing strands into a mould, in accordance with the method of the invention; Fig. 2 is a plan view of typical form of apparatus constructed in accordance with the invention; Fig. 3 is a side elevation of the apparatus shown in Fig. 2; Fig. 4 is a scrap perspective view of an insertion means engaged with a disposable strip overlying a plurality of reinforcing strands and shown at an intermediate stage in the introduction of such strands into a vertical mould; Fig. 5 is a diagrammatic plan view, partly in section, and shows the relationship between the disposable strip and the mould cross-section; and Fig. 6 is a diagrammatic view, generally along the lines of Fig. 1, and shows the application of the method of the invention to a multiple-cell mould. Referring now to the drawings, and particularly to Figs. 1A to 1E thereof, a method for the introduction of reinforcing material into a vertical mould 2 in the manufacture of a reinforced construction product includes the steps of providing a multiplicity of strands 1 of the reinforcing material arranged in parallel side-by-side disposition across the open top of the mould, engaging each strand 1 by means of a vertically movable insertion means 3 and causing such insertion means 3 to move progressively downwardly into the mould cavity 4 so as to draw said strands from respective continuous supplies 5 thereof and locate the same in spaced disposition relative to and throughout the full vertical extent of the opposing mould surfaces 6, 7. The strands of reinforcing material are positioned to overlie the open top of the mould by means of a reciprocable carriage 8 supporting side-by-side strand guide tubes 9, one for each strand and of which one only is shown, the carriage 8 further providing a selectively operable strand clamp 10 through which the strands 1 pass in moving from the respective continuous supplies 5 to the tubes 9. A further selectively operable strand clamp 11 is provided at one side of the mould, being that side remote from the said continuous supplies 5, whilst a cutting means 12 is provided at the other side of the mould. The insertion means 3, which means 3 may, as in the illustration, comprise core formers intended to remain in the mould during the filling thereof or merely pushers which position the strands and are then withdrawn to be replaced by core formers, engage the strands 1 through the medium of a semi-rigid strip 13 which serves, in conjunction with spacer beads 14 on the mould sides, the locate the strands within the mould. The sequence of operations is illustrated by the successive Figs. 1A to 1E. Thus, referring particularly to Fig. 1A, with insertion means 3 in a position remote from the mould, and with clamps 10 and 11 respectively closed and open, carriage 9 is advanced such that the protruding end of strand 1 is positioned for engagement by clamp 11 on the closing thereof. The condition of clamps 10 and 11 is reversed and carriage 9 is then withdrawn to the position shown in Fig. 1B. On lowering the insertion means 3 into the mould, the semi-rigid strip 13, mounted on lugs at the lower ends of such means, engages the strands and pushes such strands downwardly into the mould cavity, (Fig. 1C), strand material being drawn from the respective supplies 5 through open clamp 10 against the restrain of a tension means 18 between the strand package 5 and carraige 8. Tension in the strand is of importance, and needs to be accurately controlled. Movement of the insertion means continues until the cross-head 15 (from which the insertion means 3 depend) engages the top of the mould to clamp the strands thereagainst, as is shown in Fig. 1D. It will be observed that the strands are held in spaced apart, taut parallel relationship with respect to the opposing mould faces, being located by the mould beads 14 and the corresponding edges of strip 13, and being in taut condition by virtue of the tension introduced by the tension means aforesaid and the clamping effect of the cross-head 15 on the top of the mould 2. Fig. 1E illustrates the filling of the mould, the insertion means 3 remaining in position during such filling and providing a means of effecting powder compaction after vibration, in accordance with the teaching of our GB-A-2183200. Since the semi-rigid strip 13 is not normally a sufficiently close fit to prevent leakage of powder during filling, in view of the vibration to which the mould is subjected during the filling operation, it is convenient to provide a rubber pad between the mould base and vibrator table, the pad 16 and table 17 being identified in Fig. 1E. Once the powder is compacted, it will not leak round the strip when the mould is lifted from the vibrator table. The reinforcing strands may, for example, be of metal, plastic or glass-fibre, and a typical tensile reinforcement for a gypsum wall panel would be a glass fibre roving of 600 tex. Whilst the spacing between adjacent strands will vary according to specific circumstances, in the wall panel aforesaid a typical spacing would be 15 mm. Apparatus for use in introducing reinforcing strands into a vertical mould in the manufacture of a partition panel from mouldable dry powders or powder/fibre mixes in accordance with the method of the invention is shown in Figs. 2 to 5 and comprises a wheeled carriage 31 movable on guides 32 between a retracted position as shown and an advanced position wherein the forward end 33 of the carriage overlies the open upper end 34 of a vertical mould 35, a multiplicity of spaced parallel strand tubes 36 arranged in horizontal disposition in an upstanding flange 37 of said carriage, a strand clamp 38 extending transversely of the carriage 31 at the rearward end thereof, and displacement means 39 operably connected between the wheeled carriage 31 and a fixed lug 40 provided at the underside of a strand creel 41. Guide tubes 36 will have smooth rounded edges, and be of a sufficient length and close diameter to support the free end of the strands without excessive lateral slewing or dropping. As an alternative to guide tubes, as such, grooves, plates or bars may be found to be preferable. The apparatus further includes a second strand clamp 42 adjacent the open end of the mould and positioned at that side of the mould remote from the carriage guides 32. Carriage 31 consists of a generally square chassis 43 having wheels 44 secured thereto, the chassis supporting a plate 45 which extends forwardly of the chassis and presents flange 37 at its forward end, the clamp 38 being adjacent and above the rear edge of the plate and extending throughout substantially the full lateral extent thereof. Yarn clamp 38 is provided at the underside of a rigid bar 46 secured in spaced parallel disposition relative to plate 45 and its position is controlled by a pneumatic piston and cylinder arrangement 47 mounted on the said bar 46. Displacement means 39 likewise comprises a pneumatic piston and cylinder arrangement. Creel 41 includes a multiplicity of spindles (not shown) each to secure a respective strand package and a corresponding multiplicity of guide rods 48 mounted in spaced disposition on and upstanding from a triangular base 49, the spacing of the rods 48 when viewed from the front of the carriage, corresponding to the spacing of the yarn tubes 36 in flange 37. The second strand clamp 42 is positioned in generally horizontal alignment with the array of tubes 36 and is attached to a fixed guide rail 50 on which the mould 35 is movably mounted for transportation purposes, the clamp comprising an elongate clamping plate 51 arranged in opposed disposition relative to a fixed clamp plate 52 sensibly coextensive therewith, clamping plate 51 being movable towards or away from fixed plate 52 by pneumatic piston and cylinder means 53. A second guide rail 54 is provided in spaced parallel disposition relative to guide rail 50, such rail 54 likewise supporting the mould 35 during transport thereof, there being an elongate platen 55 arranged below and in spaced parallel relationship to guide rail 54. The blade 56 of a rotary knife assembly 57 cooperates with the platen 55 in severing strands 58 which overlie said platen, said assembly 57 being movably mounted on a fixed bar 59 extending parallel to guide rail 54 and being shiftable axially of bar 59 by pneumatic piston and cylinder means (not shown). Other cutter assemblies, for example, a guillotine may be used. The apparatus further includes an insertion means engageable with a sheet of strands 58 extending across the open upper end 34 of the mould 35 between tubes 36 and clamp 42, said insertion means being reciprocable relative to the mould through the full vertical extent thereof. In the arrangement illustrated in Fig. 4 the insertion means comprises a plurality of rigid elongate elements 60 vertically arranged in spaced side-by-side disposition, said elements 60 depending from support means, not shown, whereby they can be lowered into position within the mould 35. In the context of the manufacture of a cored partition panel, the rigid elongate elements 60 may comprise the inflatable core formers present in the mould during the filling of the same with a powder or powder/fibre mix and the subsequent compaction thereof. The insertion means engage the sheet of yarns 58 through the medium of a rigid or semi-rigid strip 61 located at the underside of the rigid elongate elements, across the underside of which the strands move on progressive lowering of the insertion means, the strip 61 being of a length and width to conform to the corresponding plan dimensions of the mould cavity and being profiled, as at 62, to receive pins 63 at the lower extremities of the elongate elements into cooperable engagement therewith. The edges of the semi-rigid strip may also include recesses 64 to receive the respective strands and accurately to locate such strands in the longitudinal direction of the strip as the strands move relative to the strip on progressive downward movement of the strip Strip 61 will ordinarily be of cardboard, and will become part of the finished partition panel, although "cards" of plastic or metal may be used if preferred. In these latter circumstances the re-usable strips will, if necessary, be profiled, radiussed or the like, to avoid damage to the strand on movement thereacross, and will be retrievable by trimming off the end of the panel. By suitable dimensioning of the "card", the extent to which the strand is spaced from the mould surface may be varied to suit particular requirements, a typical spacing being, say, 2 mm. In addition to its function in providina an intermediary between the insertion means and individual strands, the "card" serves to locate the lower ends of the core formers accurately within the mould and also effectively "closes" the bottom of the mould thus holding the powder in place during mould transfer and post-filling processes. The continued presence of the "card" in the finished product provides a strengthening membrane at the base thereof. As an alternative to locating the cards against the opposing mould faces, with appropriate cut-outs 65 to accommodate the spacer beads 66 provided at the top of the mould, said cards may be profiled to cooperate with the tongue and groove formations at the mould ends. The sequence of operations necessary to introduce reinforcing strands into a mould cavity is analogous to that identified by reference to Figs. 1A to 1D, and further description is not thought necessary. It is to be understood that if the cross-head from which the insertion means/core formers depend does not engage the top of the mould sides to clamp the strands thereagainst some alternative clamping means will be provided to maintain the strands in taut condition. The method of the invention is illustrated in Figs. 1A to 1E hereof in the context of a single cell, but it is equally of application in the context of a multiple-cell mould, such an arrangement being shown diagrammatically in Fig. 6 of the drawings. As is apparent from the drawing, the core former 70 of each of the successive mould cavities 71 is lowered upon completion of the movement of the previous core former and the carrier 72 is withdrawn in step-wise manner across the multiple mould openings. As indicated, a clamp 73 and a cutting means 74 analogous to clamp 11 and cutting means 12 of Figs. 1A are provided at the end cells respectively of the multicell mould. The invention is not limited to the detail of the arrangements herein set forth, since alternatives will readily present themselves to one skilled in the art. Thus, for example, whilst the invention is disclosed in the context of construction products moulded from dry powders or powder/fibre mixes, the method and apparatus are throught likely to be of application in other contexts where reinforcement is required. Furthermore, although the embodiment hereindisclosed serves to introduce a U-shaped yarn run, an analogous arrangement may be used for the introduction of a single run of yarn. It is to be understood that, notwithstanding that the arrangement illustrated in Figs. 2 to 5 shows otherwise, strand clamp 42 and cutting means 57 may operate against bearing surfaces, typically of rubber, provided on the top edges of the mould sides, in like manner to the arrangement shown in Fig. 1.

Claims: 1. A method for the manufacture of a cored construction product, including the steps of introducing at least one axially reciprocable core former (3) into a vertical mould (2) through an open top thereto, feeding powder or a powder/fibre mix into the mould, compacting the powder or powder/fibre mix and withdrawing the said at least one core former to provide a respective core void or voids, characterised by the preliminary steps of positioning at least one flexible reinforcing strand (1) to overlie the open top of the mould (2), securing one end of the or each strand (1) against longitudinal movement, providing an elongate strip (13) in parallel relationship to and at that side of the said one strand remote from the said open top and engaging said strip (13) with an insertion means (3) reciprocable into and out of said mould, and progressively moving said insertion means (3) into the mould (2) thus to draw a requisite length of said at least one reinforcing strand (1) into the mould to exist therein in tensioned state and to extend throughout substantially the whole of the vertical extent of the mould (2). 2. The method as claimed in claim 1, wherein each strand (1) is positioned to extend across the said open top by feeding from a strand supply (5) at one side of the mould (2) and the free end of the strand is clamped at that side of the mould remote from the said supply, the strand moving relative to the insertion means (3) on progressive engagement of said insertion means with the mould. 3. The method as claimed in claim 1 or 2, wherein a plurality of reinforcement strands (1) is introduced simultaneously into the mould (2), said strands being provided in spaced side-by-side disposition and being engaged by a common elongate strip (13). 4. The method as claimed in any one of the preceding claims, wherein the insertion means (3) comprises the said at least one axially reciprocable core former and engagement thereof with the elongate strip (13) includes the positive location of one relative to the other. 5. The method as claimed in any one of the preceding claims, wherein the or each strand (1) is provided in such lengths as to define a loop of reinforcement extending from top to bottom of the mould (2), the method including the further step of clamping the trailing end of the or each strand (1). 6. The method as claimed in claim 5, wherein the said trailing end is clamped on completion of the downward movement of the insertion means (3). 7. Apparatus for introducing one or more reinforcing strands (1) into a vertical mould (2) comprising a carriage (8) movable between first and second positions relative to the open top of the mould and respectively corresponding to advanced and retracted positions of the carriage, a first selectively operable strand clamping means (10) on the said carriage (8) to receive a reinforcing strand or strands (1) into engagement therewith, a second selectively operable strand clamping means (11) at that side of the said open top remote from the said carriage (8) likewise to receive the reinforcing strand or strands (1) said first and second clamping means (10, 11) being actuable to clamp strands (1) engaged therewith, and insertion means (3) in alignment with the open top of the mould, the said insertion means (3) being reciprocable in the plane of the mould and being adapted upon such reciprocation to engage each said reinforcing strand (1), to draw the same from a supply (5) thereof and to introduce said strand or strands (1) into the mould throughout the whole or substantially the whole of the vertical extent thereof. 8. Apparatus as claimed in claim 7, wherein the insertion means (3) is cooperable with an elongate strip (13) extending transversely of and releasably engageable therewith, the elongate strip (13) being positionable to overlie each said reinforcing strand (1) and the insertion means (3) engaging each strand (1) through said strip (13). 9. .Apparatus as claimed in claim 7 or 8, further including a third selectively operable clamping means at the side of the open top remote from the second clamping means and cutter means at the carriage side of said third clamping means. 10. Apparatus as claimed in claim 8 or claim 9 when dependant thereon, wherein the insertion means (3) comprises a reciprocable core former, the lower end of the core-former being releasably engageable with the elongate strip (13) and said elongate strip being dimensioned to be an interference fit in and transversely of the mould on full engagement of the core former with the mould thereby to locate the strip in the mould.

Inventors: BEVAN, CHRISTOPHER GRAHAM
Applicants: DRYFLOW LIMITED
Application year: 1988
Main classification: B28B23
IPC codes: B29C70, B28B23