CA1075142A - Fabric construction useful as building bases in forming compound-curved structures - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A new and further improved multi-ply fabric, and process for the manufacture of such fabric, particularly useful in boat building wherein the fabric must fit or assume the shape of compound-curved surfaces to suitably serve as a base or support for resin or liquefied plastics added thereon and cured or hardened as an initial step in the formation of, e g., a fiberglass reinforced plastic boat hull. The fabric is characterized generally as of a two-ply construction embodying an upper and lower ply between which is "sandwiched" and secured a series of parallel aligned, spaced apart, springy elements of specific character between which can be placed yarns or rovings to impart tensile strength. The plies of the fabric consist of parallel aligned, continuous, pliable filaments bonded to said springy, plastic elements, each filament being laterally aligned with respect to said springy elements, the filaments being sufficiently pliable or flexible to permit some lateral or tansverse movement, and also longitudinal movement, of the springy elements so that the fabric construction can assume compound-curved shapes.

Description

~CD'75 1 FIE~.n or T~ VENlI0:~

2 ~1is invcntio~ relatcs to multi-ply fabrics, or fabric

3 constructions, uscful for assuming the sh~pcs of compound-curvcd

4 objccts on which thcy are placed as bases for support of resins or liquefied plastics added thereto and cured and hardened in 6 the shape of the compound-curved objects as an initial stcp in 7 the formation of laminated structuros. The fabrjcs have particular 8 utility in a process for the construction of ib~rglass reinforced 9 plastic boat hulls. The invention also relates to a method or - lO process for the manufacture o t1~ese fabrics;
', ", I

S P E C I P I C A T I O N
li U.S. patent No. 3,668,051 discloses a mono-ply fabric 12 type of const~uction comprising a ~ase of flexible, or plia~le, l3 sheeting material, e.gO, a loosely ~oven textile fabric, on which 14 a series of spaced apart elastic,.resilient or springy elemem s ~re secured End aligned in parallel ~elationship, one element in 16 relation to another. The base material is porous~ and of necessity l7 sufficiently pliable ko permit transverse movemen~, and also 18 limdted longitudinal mavement, of the springy elements, one in 19 relation to another, so thak the mono-ply fabric structure can be ~itted to a boat frame to assu~e its compound-curved shape and then 21 secured thereto to serve as a base upon which resins and liquefied 22 plastics can be applied as an initial step in fo~ning a fiberglass 23 ~einforced boat hull. Af~er the mono-ply fabric is so fitled, as 24 disclosed in said patent, by extending t}1e fabric from XPe1 tO
25 gunwhale, aligning the springy elem~nts ~o tha~ th~ major axis 26 thereof is in a direction perpendicular to the alignment of the ~7 keal, the resinous ~r liquid plastic is ~hen addcd in quantity 28 sufficiont to fill troug1s betwccn ~he spri11gY olements~ In a 29 subscquent stçp, a~tor the liquid plastic Ol` resin h~s set and ¦ ~

. ;~ . ' ~ :

g~75~
h~rdened, a mixture of larninatlng resin, talc and chopped fiberglass is brushed or otherwise applied and then rolled to produce a relatively smooth, strong shell substructure which is then sanded to remove the high spots.
Such mono-ply fabric has proven adrnirably suitable in forming boat structures~ and such method of construction has added considerable flexibility in boat building, particularly as compared with prior art methods necessitating the use of molds, which of course do not become a part of the finished boat but rather serve as a means within which a fiberglass boat can be laid, constructed and then removed. ~Ihile the use of molds in boat constructions yet offer some benefits, mold constructions, inter alia, are extremely costly, particularly where only a relatively few boats of given design are to be built. In other words, a mold is produced for use in constructing a single type boat. Change of design is not possible without changing thé mold. The cost of the mold, however, must be added to the cost of the series of specific type boats constructed with a given mold, and hence the cost of the mold itself is added overhead or burden, particular-ly prohibitive where relatively few boats of a given design are to be constructed.
Prior to the inception of the invention described in said patent, supra, little had been done to change boat building methods requiring mold constructions. Prior art methods generally involved use of molds, or form work which, after initial use to define the shape of the hull, was separated from the hull and did not become part of the finished boat construc-tion. Previous attempts, if any, to manufac~ure boats without the use of molds, or forms which were separated from the boat after it had been formed, apparently have not been successful. For example, an attempt to form a boat ~; ~ construction wherein a type of fabric, which was to ultimately become a part ; of the finished structure, ls described, e.g., in U.S. Patent 2,813,050 to ; Wllllam F. ~lckman, issued November 12, 1957. Pursuant , ..

',' ' . ~ , ' ' :: ~ .. ., , : . .. . .
. .

S14'~

to the disclosure oE that patent, stlf~ wLre mesh was used to cover a frame~
work, basically conforming to the shape of a boat, over which a fabric or fiberglass matting was placed as a base, and then resin poured thereover, and permitted to harden. Layer after layer of ~he resin was applied and hardened until such time as the desired hull thickness has been obtained.
The framework, after having imparted its basic curvature, shape of sides and bottom shape, was separated from the wire mesh-resinous structure~ In some instances two layers of wire mesh were used with an intervenlng g]ass fiber matting, or the wire mesh was sandwiched between two layers of glass fiber matting. The surface of the precast hull containing th~ wire mesh, or meshes, was then buffed or ground for smoothness. This technique apparently has not proven successful, inter alia, because the structures so produced simply cannot withstand the frequently changing stresses, mechanical and - thermal, to which a boat is necessarily subjected. The wire mesh, particular-ly under the stress of wave actions, has not proven to be an effective rein-forcement. This is believed due to the relatively low surface area of the individual wire strands constituting the wire mesh relative to their cross-sectional area, The low ratio is simply not large enough to allow the wire to be effectively bonded into the plastic matrix with sufficient bond strength to keep the individual wires from being broken loose under stress. The metal wires, after breaking loose from the plastic matrix, are all too readily stressed beyond their elastic limit. The result of the breakdown of the bond between the metal wires and the plastic matrix is crazing or frac-turing of the laminate, and this can even result in permanent deformation of the hull structure.

~ .
' - - 4 -' .. , . .. . . .: . .. . . .. . .
, :' ~' ' :- ' - ' ," . ' .', ~ . ' : . ' . ' ' ' : . ' ' ,, ' ' ~ ' :. :' ', ,. ' . . .

~ ~Lo75~

Further improvements in the art o~ boat building, in any event, are made possible by t~le invention described in U.S. Patent 3,895,160 supra, which covers multi-ply fabrics. The multi-ply fabrics are used in boat building in much the same manner as the mono-ply fabrics, but are superior to the latter. The multi-ply fabrics, inter alia, possess greater tensile and flexual strength due to the presence of reinforcing fibrous yarns or rovings, especially fiberglass yarns or rovings, which are loaded within voids between elongate plastic elements. The fiber, or glass-resin, ratios are such as`to import tremendous tensile strength, and the yarns arld rovings absorb or soak up applied resins and liquid plastics to prevent resin drip through at the time the resin is applied. A far superior finish is produced by virtue of uslng the multi-ply fabrics as contrasted with the mono-ply fabrics, and less labor is required for sanding down and smoothing the finished hull.
The multi-ply fabrics, like the mono-ply Eabrics, are admirably suitable for their intended purpose. Nonetheless, it is found that even the multi-ply fabrics are susceptible to further improvement. For example, in the multi-ply fabrics it is found that the warp yarns contained in the outer plies lessen the flexibility of the fabric and, to some degree, this makes Z0 it more difficult to lay the material to cover and assume the shapes of com-pound-curved structures. ~oreover, the strength added to ~he structure by ~- the warp yarns is achieved at extremely high cost. The warp yarns contri-` bute very little to tensile strength, which is the type of strength that is ` most requlred, and hence the cost-effectiveness of the warp yarns i5 extreme-ly low.
Accordingly, this invention obviates the foregoing and other prior art deficiencies, particularly by providing new and further improved fabrics, and , ~ - 5 -. ' ~ ' ' . ' ' , . . .
' ' ' ' ', ',' ` '', ' ' '. "` ` ', ' ' ' ' ' ' , ~ ' ~ , ', `, ,' , . ,. ~ j ' ' ' ", ',' .. ' ` ; ' 75~
processes ~or the manufacture and use of such fabrlcs, in the constrllction of laminated structures of compound--curves and various other shapes.
The inventLon also provides new fabrics suitable for use in boat constructions, which constructions can admirably and long withstand thermal and mechanical stresses, such as caused by weather and continuous wave actions.
The new fabric of this invention is smooth on all faces, and improved over that described in U.S. 3,668,051 and in ~.S. 3,895,160 supra, which material is easy to manu~acture at further reduced cost.
~ Thus in accordance with the present invention, there is provlded a multi-ply fabric, or fabric having a plurality of plied layers, including outer plied layers oE pliable or flexible continuous filaments or fibers, suitably yarns or rovings of fibrous, or fibrous textile materials between which is sandwlched a plurality or series of parallel aligned, spaced apart, elastic, resilient or springy elements. The latter, of elongate shape, are constituted of semi-rigid or rigid plastic or plastic-like materials, pre- -ferably hardened or cured resins reinforced by yarns or rovings, preferably glass rovings, to impart high tensile and flexual strength to the fabric.
The mechanical properties of such fabric are excellent because, e.g., the fiber-resin or glass-resin ratio in the springy elements can be accurately controlled to provide high fiber or glass loadings and the reinforcement highly oriented and unidirectional in the direction where strength is needed.
i Preferably, yarns or rovings, more preferably glass rovings, are placed within the voids or spaces between the springy elements, and oriented in the same direction as the latter. These yarns or rovings not only add ten-sile strength : ~ ' ~ - 6 -', ,.' ' '; . ' ~ '. . , ' ~ . . ,, J
' , ~ ' . ' ' '' . ' . ' ' ' , ' ', ' '~,, ' ~,', ' ' ~' . " ., ''. '. " . ' ' , .'.,'' ", '', `' '~'".' '',','" ''', '' " ,; ', . ', .:
'`';'' ' ''' ' ' ,, ', "' ' " ', .~ ' ,, ' , .'' ' '' . '' "
'' " .'."' `'''. ' "", '." ' ~'' ' ,~ ,'' ' , ' ,, ' ', ' ~ ' ' , , , ' ' ,,, ' , `,, ' ; ' ' '. . ' '' ' '. ' : ' ' ' ' ' ' " " : ' ' 7~
\
to ~he fabric buL also absorb or soak up applied resins and liquid plastics to prevent resin drip~through at the time such materials are initially applied.
The outer plied layers of pliable, or flexible, continuous fila~
ments or fibers of the structure are laterally or perpendicularly oriented as relates to the direction of alignment of said springy elements, and the yarns or rovings placed therebetween and within the voids which separate said elements. They constitute continuous filaments, e.g., monofilaments, spun fibers or threads, strands, yarns or rovings composed in whole or in part of natural or synthetic flbers such as cotton, rayon, Dacron*, nylon*, 10 Orlon*, acetate Acrilan*, Crlslan*, Dynel*, ~ortel*, Kodel*, glass fibers, wool and the like. Slnce these materials add little to tensile strength of the composite fabric structure, high strength is not particularly crltlcal ln their selection, but lt is essential that they be bondable to sald sprlngy elements, elther by virtue of their own nature, or the reslnous quallty of the sprlngy element, or both. In elther event, the materials can be bondable by virtue of their own inherent quality, or by vlrtue of a resln applied to ; either, or both.
Fibrous materials as used in the construction of the sprlngy ;elements, or as yarns or rovlngs for use in impartlng great tensile strength, 20 are constructed prlnclpally of fibers o~ average diameter no greater than , about ten thousandths of an inch ~10 mils), and preferably average fiber ~ dlameters range from about one thoùsandth of an inch ~1 Tllil), and smaller, to -~ about ten thousandths of an inch (10 mils). Preferably, the fibrous textile ~ materials used in the construction of the springy elements, or as yarns or ; ~, . . .
~ rovings for containment within the ~oids, are those having a tensile strength ~ . :
of at least about 200,000 pounds per square inch (psi), and preferably 300,000 psi, and hlgher.
, ~ : : . .
~ *~Trade Mark ~ . ~
, . ~
: ~ , .

... . -., '1 , ~ ~ .. - . . . ... .. . ..

.- .~. : : ' ., , :

7S~2 . ~ , ~ c outor plics of the f~l)ric, whctllcr continuous fila-2 mcnts9 yarns or rovill~s, aro spacc~i apart, onc fro~-i anothcr, 3 gcncrally at distances approxiLrllating O.l to 3 timcs the distance 4 between adjacent sprin~y elements (center to centcr) and, as such, readily pcrmit passago o~ liquid plastic or resin to fill and 6 saturate all of the void space, or yarns and rovin~s, bctween - 7 the springy elemcnts, as when the material is used in construction.
8 Complete wet-through is essential. Tlle outcr plies must, in all 9 emibod;ments, be sufficiently pliable or flexible ~o permit botl~
transverse and lon~itudinal displacement of thc springy elements 11 so that the fabric can assume the form of compound-curved struc-12 tures, 13 The fabric is particularly use~ul as a building base in 14 forming compound-curved structures, an~ is particularly useful in .. ... .
lS ~oat const~uctions to produce boat hulls, decks, tanks, equipment , - 16 lock~rs, cabinsJ and the like. Tanks can be formed without use i 17 of a mold, e.g., by wrapping the fabric circunferentially around 18 a ~ra~ewor~ and then saturating the fabric with liquid plastic or , ~ 19 resin. The r~sin, upon hardening, can be ~urther coated with ' ~ ~ 2r additlonal layers of resin, ~iberglass, and the likeJ as desired, ~ . ~ ~ . .
21 to form a raminar structure of suitable thic~ness. A boat hull, 22 e.g., can be similarly constructed by placing t~e fabric on a 23 framewor~ ~ith the springy elements and unsaturated rovings ali~ned 24 in the direction that strengtll i~ needed--viz.9 parallel to the Z5 ~direction ~ the keel. The fabric is smooth on the outer faces, 26 such that a minimum amount of sanding is required to prou de a : i ~ .
; 27 smooth surPace upon which to apply ~urther layers of plastic. The 28 fabric~is also sufficiently porous to soak up ~pplied resins and 29 liquid plQstlCs, but~does not permit ready pour-tilrough o.. these ; 30 waterials at tlle time of application.
u :

~ ' 'A ' ~ . ' i j ', : ~

1~'75~

Generally, upon completion of the lclmLnated structure, the frame, e.g., boat hull, becon~es an integral part of the obJect of the construction.
In some instances, however, the laminated structure can be separated from the frame, and the latter used continuously, if desired, as a mold.
The invention, and its principle of operation, will be more fully understood by reference to the following detailed description of a specific embodiment, and to the attached drawings to which reference is made in the description. In the description, similar numbers are used to represent simi-lar parts or components and, where subscripts are used :Ln conjunctlon with numbers, the numbers indicate a plurality of similar parts or components.
Numbers used without subscripts, where similar numbers have been introduced with subscripts, are intended in generic sense.
In the drawings:
Figure 1 is a top plan view, in partial section, of a representa-tive segment of a multi-ply textile fabric construction in accordance with a preferred embodiment of this invention;
Figure 2 is a section view taken along line 2-2 of Figure l; and Figure 3 is a schematic or diagrammatic view of apparatus and process useful in forming the multi-ply fabric construction depicted in the two preceding figures., Referring to Figures 1 and 2 there is shown a segment of two-ply fabric 10 embodying an upper ply 11 and lower ply 12, the upper ply 11 being comprised of substantially parallel aligned yarns 111 while the lower ply 12 is comprised of substantially parallel aligned yarns 121. The yarns 111, 12 constituting the outer plies 11, 12 are necessarily of flexible or pliable .
material. Suitably, the individual plies ll, 12, which can be the same or different, are formed of~textile yarns, of fibrous materials.

_ g _ :,, ~.~.

.
: . ' . - : , .
:' ,. . .
, :~ ' . ' .
: . : .

`` ' ~C~753L41L'~
;, -- .

, 1 l~c plios 11,12 ~rc sc~ratcd an~ rctained su~st~ntially ~rallcl, 2 onc mcm~cr Witil respcct t~ thc othcr, by a plur~lity or scrics of 3 spaced apart elastic, rcsilient or springy clcmcnts 13 sand~liched 4 bctwcen and, prefcrably, bonded to the indivi.dual yarns wllich

5 .constitute the plies. A series of yarns or rovings 14 is con-

6 tained within the voids between the individual elements 13, the

7 rovings imparting tensile strengtil ~o the fabric.

8 In its preferred form, thc individual yarns 111,121 of g plies 11,12 can be constituted of virtually any fiber which is compatible with the resin coating to be applied and su~ficiently 11 pliable to p~rmit substantially unimpeded or free displacement of 12 the individual elements 13, including movement toward ar away 13 ~rom one another~ as well as movement in a direction lateral or 14 t~ansverse to the major axes of the said elements 13, but most 15 particularly movement in a longitudinal direction, Longitudinal 16 movement of elements 13 in a direction transverse to their major 17 axes is essential for the ~abric in its assuming a compound-curved 18 sh~e. ~e individual elements 13 are selected to provide the 19 necessary stiffnes5 in the longitudinal diTection, or in the 20 direction of the major axes of elements 13. Suitably, yarns ll~
21 w~ich constitute plies 119~2 are composed in whole or in part of 22 ~atural or synthetic fibers sueh as cotton, rayon, Dacron, nylo~
:* * * * * *

23 Orlon, aceta~e, Acrilan~ Creslan, Dynel, Fortrel Kodel, wool, and ~ :

24 the like. A yarn constructed in ~hole or in part of glass fibers, :: ~ 25 particularly the ldtter~ is especially preferred, : . 26 . . The springy eleme:lts 13 are in the form of elongate -27 members oriented in parallel relationship, one member relative to : 28 another. These ele~ents 13 aTe suitably constructed of a solid, I

29 ~igid;or semi~rigid plastic3 preferably hardened or cured resins 30 within ~ icll ~re incorpo~atet fibsous, or f;brous textilc materials, .
. . .
. * Trad~ Mark .
r~ ~ 10 ~
'.

, .

1C~75~LZ

1 suitably yarns or rovings. Tho hi~lh r~tio of thc surfacc arca 2 relativo tO-tllo cross-scctional ~rc~ of tl-e in~ividual fibcrs, 3 which are thorou~hly wcttc~ by rcsin or liquid plastic an~l set, 4 cured or haTdened so that thc in~ividual fibers are strongly bonded togetllcr with the plastic which sorves as a matrix for 6 the fibers, provides sufficient strength to prevent the fibers 7 from being pulled apart or broken loose one from another when the 8 finished structure is subjected to great stress. The ability of

9 this material to withstand great stress, e.g., is sharply con-trasted with metal wire, which has not proven an effective 11 rei~forcement for structures subjected to high stresses, e.g., 12 ~oat hulls. This is because wires have a low surface area rela-13 tive to their cToss-section and there is, inter alia, insufficient 14 surface fvr the wire to be effectively bon~ed into a plastic atrix with adequate bond strengt}l to prevent its being broken 16 loose when the wire is stressed. Moreover, the tensile strength 17 ~f available metals is inadequate and certainly far below that of a~aila~le fibrous materials. Consequently, metal wires can be 19 easily stressed beyond their elastic limit long be~o~e the more resilient reinforced plastic material within which the metal is 21 embedded reaches its elastic limit~ The result is a breakdown 22 of the bond between the metal ~nd plastic, crazing and fTacturing 23 of ~le la~inate and even possible permanent deformation of the 24 hult structure. ~urthermore, fibrous materials ~e far easieT
to work with th~n ~ire ~esh, pre~ent a smooth suYface, do not 26: peTmi~ significant ~esin d~ip-through, provide a high strength-27 weight ratio, and ~he incorpora~icn of fibe~s in~o the hull shell 28 ~is adlrantageous in that th~re is no probiem of corrosion or 29 develop~ent of electrical and magne~ic fields which is quite ~important in somc usages~, ~1375~4~2 1 Suit~ ly, the s~rin~y clomcllts 13 can be constructo~ of 2 various thcrmosetting or tll~3rmo~1astic plastics or ~lastic-like 3 materials. Exe~lary of such plastic matcrials arc polystyrenc, 4 polyetllylenc, ~olyvinyl chloride, polyvinylidcne chloridc, poly-5 vinyl acetate, cellulose aceta~e, cellulose nitra~e3 cellulose 6 acetobutyrate, ethyl cellulose and the like. The elements 13, in 7 accordance with an especially des~red technique, can be3 made by 8 dipping or impre~nating various yarns with resinous materials 9 which, after setting or solidifying, by various suitable methods, lO form the desirable rigid or semi-rigid shapes. Glass roving is an 11 e3specially preferred fibrous material for such us~. ~or example, 12 glass Tovings, which add tensile strengtll to the elements 13 13 ~oTmed therefrom, can be sprayed, dipped or othervise impregnated 14 with various resins, shaped as desired, and the resin then solidi- :
15 fied and hardened to form the said elements. Glass -roving thus 16 impregnated with various resins, e.g., e3poxy resins, polyesters, 17 phenolic ~r melamine resins, of the thermosetting type, in a 18 preerred embodiment, can thus be heat set to form rigid shapes 19 suitable ~or use as springy elements. By preplacement o~ the b resin impregnated yarns of various types between the plies 11,23 , ~ . 21 in desired orientation, ~he springy elements 13 can, in either .
22 event,~be si~ultaneously bonded to the ~n~eloping plies 11J12 at 3 23 *he time of setting. 3 .
24 The elements 13, as stated3 are spaced apart in parall01 orienSation,~eaving voids or poc~ets which are filled with yarn ?6 ~ or ~ovings 14, the functior. of which is to impart ~ensile strength 27 to the ~Fabric 3and lessen drip-through. In a construction3, there-28 ~ore, tlle fa~ic lD is pre~erably laid so tiiat ~he ~ovings 1~ tand 2g conse~lently also the m~jor axes of the springy elements 13) are ~ligne~-in the samo direction as the keol, this bein~ the ~irection :~. : : ;

, , Z

: ~ ` '`/
: :, 1~7~
1 of ~rcntcst strcss pro~luccd by w~vo actions whcn thc boat is in 2 uso. In constrllction of a cylin~lrical sh.lpcd watcr t~nk, for 3 cx~mple, thc fabrlc lO woul~ be placod so that the rovings l4, 4 and tllc major axcs of thc s~ringy clemcnts 13, are wrapp~d circum-ferentially about tllc cyllndrical frame on which a tank is to be 6 formcd. Virtually any fibrous matc~ial of goo~ strength, and 7 co~patible wîth the resin matrix to be formod upon the fabric 10, 8 is suitable for use as rovings. Exemplary of sucll materials are 9 fiberglass, carbon fiber, graphite fib~r, boron filaments, and high strength organic fibers sucll as Dupont's Kevlar and the like.
11 Piberglass rovings have been found particularly satisactory.
12 A preferred metl~od for manufacture of a suitable and 13 preferred type o~ ~abric 10 is illustra~ed by sp~cific reference 14 to Figure 3. A plurality of parallel strands of roving 151,152,153 (e.g., 211 yards/pound continuous ilament fiberglass) are unwound 16 fr~m a paTallelly arranged series of rolls 161,162,1S3 and the 17 individual strands brought together and immersed within a resin 18 19 ~e.g., a polyester lamlnating resin) by passage across rolls : ,--- , .
19 171,17~ of bath 18. The series of parallel strands 15, brought together ~nd consolidated by passage through a comb 20, is wet with 21 resin, and formed into round cross-sect;ons (e.g., o 7/64 inch Z2 diameterJ. These r~sin-saturated strands 15, ser;ally oriented 23 in parallel ~elationship one to anot~er~ aligned and spaced, e.g., 24 SJ16 incl~ apart (~easured from center to center) in alternate series wi~h similarly parallelly aligned unsa$urated strands of 26 ~oYi~gs 21 (e.g., 2~1 yards/pound continuous filament fiberglass)J
. .
27 uutwound ~ro- ~olls 22lJ222~223 ar~ directed ~hrou~h oriice 29 and ~8 comb 30, and then brou~ht forward and align~d in a singlc plaltc.
29 Yarns or rovi~tgs 23 are t]len laid î~ lateral orientation across he entire widlth, both top and bottom, of the plane or~ed by th~
* Trade Mark ,~ ' ' ', ' :

. . . . ..

~7Sl~
l' p~rallcl ali~rlc~, ~ltcrnatoly ~;srosc~ rcsin-saturatcd stran~s 15 2 an~ ulls.ltur.ltc~ rovin~s 21, Suita1)1y, this c~n b~ accomplishcd 3 by wral1ping tllC p~rallcl aligncd, altcrn;ltely dis~ose~ strands 15 4 and unsaturate~ rovings 15 with yarns or rovings 2~. ~1U5, the plane of the prccursor fabric can 'bc p~sscd through an encircling , 6 rotatably m~unted ~cmber 24, which is set within a fixcd frame 25, 7 whicl1 carries a bobbin, or bobbins, 26 and suitable gu~ tnot 8 shown) wl1icl1 wraps the yarn or ~oving 23 about the precursor 9 fabric as the member 24 is rotated. By adjusting the spced of rotation of member 24 relative to the linear speed of the precursor ll fabric, the lateral spacing o~ th~ yarn or ~o~ings 23 can be 12 readily regulated or controlled. The precursor fabr'ic is then 13 pressed lightly between two heated, Teflon coated plates or Teflon l4 coated endless belts 27,28 to.assure good contact betw~en"yarns or lS ~ovings 23 and strands l5. The applied,he,at cures the resin9 this , l6 producing flexible reinforced plastic, or springy elements bonded 17 bet~een two plies of yarns or rovings 23. The unbound reinforcing 18 IDvings 21 lie between the sp~ingy elements which are ~ormed from 19 .resin coated str~nds-l5. ., . '.
It is understood~ of cours~.t1lat the degree of heat 21 require~ to bond together the plies of yarns or rovings 23 and 22 re~in-impregnated rovings lS will vary, and different time-23 temperature relationships will be required for different materials.
24 A150D while pressing is especially preerred~ various wet or dry methods known to the art might be used to e ffect the eure. In 26 geDe~aly, a t~mperature ranging from about 200F. to about 400F.
27 is ~dequate in most cases to effect the cureO Generally, also, 28 a time duration of from about 3 to 5 minut~ is adequate tO trans-29 ~er s~ffi d cnt heat to the fabric and resin ~nd ~rovide curin~.' * Trade Mark . - - . . ' :

Claims (10)

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

1. In a fabric construction, constituting an article of manu-facture useful for covering and assuming a compound-curved shape wherein is included the combination of at least two plies, characterized as outer plies of flexible material between which is sandwiched a series of spaced-apart, parallel aligned, springy plastic elements of elongate shape, each element constructed with fibers impregnated with resin, cured, and thereby reinforced to form a semi-rigid or rigid material, the outer plies and the springy plastic elements being bonded one to the other to form the sandwich structure, the voids between adjacent springy plastic elements containing fibers in the form of yarns or rovings, the improvement wherein said plies consist of parallel aligned continuous pliable filaments bonded to said springy plastic elements, each filament being laterally aligned with respect to said springy plastic elements, whereby the springy elements can be directionally displaced one toward another, and longitudinally displaced so that the fabric construction can cover and assume the shape of a compound-curved structure.

2. The fabric construction of Claim 1 wherein the springy plastic elements are constituted of textile fibers impregnated with resin and cured to form a semi-rigid or rigid material.

3. The fabric construction of Claim 1 wherein the springy plastic elements are constructed of an admixture of resin and a material selected from the group consisting of fiberglass fibers, carbon fibers, graphite fibers, boron filaments and high strength organic fibers, cured to form a semi-rigid or rigid material.

4. The fabric construction of Claim 2 wherein the fibers have a tensile strength of at least about 200,000 p.s.i.

5. The fabric construction Or Claim 2 wherein the fibers have an average cross-section diameter of no more than about 10 mils

6. The fabric construction of Claim 1 wherein the voids between the elongate plastic elements are filled with textile fibers, aligned in the same direction as the elongate plastic elements.

7. The fabric construction of Claim 6 wherein the fibers are selected from the group consisting of fiberglass fibers, carbon fibers, graphite fibers, boron filaments and high strength organic fibers.

8. The fabric construction of Claim 6 wherein the fibers have a tensile strength of at least about 200,000 p.s.i.

9. The fabric construction of Claim 6 wherein the fibers have an average cross-sectional diameter of no more than about 10 mils.

10. The fabric construction of Claim 1 wherein the outer plies are constructed of yarns or rovings bonded to the elongate plastic elements.