Warp/knit reinforced structural fabric

A warp/knitted multi-ply structural fabric sheet which is non-woven and non-crimped and capable of being used in structural applications, said fabric sheet being comprised of:

• a plurality of plies other than 0.degree. plies disposed upon one another, each ply being formed of parallel non-overlapping fibers laid side-by-side, and the fibers in one of said plies being oriented at an angle to the fibers in one of the other plies;
• a 0.degree. ply located in said fabric sheet other than on an upper surface thereof;
• one of the plies having a fiber areal weight which is different from the fiber areal weight of another of the plies;
• and
• a thread stitched through the plies to warp/knit the plies together into a structural fabric sheet.

A process for producing a thick multi-ply warp/knitted structural fabric sheet which is non-woven and non-crimped and which sheet can be used in structural applications, said process comprising:

• a) applying a plurality of plies to one another in facewise engagement, each ply being formed of parallel non-overlapping fibers laid side-by-side, and where the fibers in at least one of said plies are oriented at an angle to the fibers in other of said plies;
• b) forming a 0.degree. pre-stabilized ply by laying fibers side-by-side in parallel and non-overlapping relation in a 0.degree. direction relative to the fibers in the other plies, and joining the 0.degree. fibers to one another by a joining material;
• c) applying to the plurality of plies the 0.degree. pre-stabilized ply in a position other than on an upper surface of said fabric sheet;
• and
• d) stitching through the plies with a thread to form a warp/knitted structural fabric sheet.

A process for producing a thick multi-ply warp/knitted structural fabric sheet which is non-woven and non-crimped and which can be used in structural applications, said process comprising:

• a) applying at least three plies to one another in facewise engagement, each ply being formed of parallel non-overlapping fibers laid side-by-side, and where the fibers in at least certain of said plies are at a different angular relationship than the fibers in others of said plies, and stitching the plies together to form a first fabric stack;
• b) applying at least three plies to one another in facewise engagement, each ply being formed of parallel non-overlapping fibers laid side-by-side, and where the fibers in at least certain of said plies are at a different angular relationship than the fibers in others of said plies, and stitching the plies together to form a second fabric stack;
• and
• c) warp knitting said two fabric stacks together to form a sheet with at least six plies.

A method of producing a spliced warp/knit structural fabric sheet having a width substantially greater than that fabricated on a specified high quality output warp/knit machine subsequently used to produce the fabric with no substantial loss of mechanical properties at a splice joint thereof, said method comprising:

• a) warp/knitting a plurality of first plies of a fabric material and where one of the first plies has a width which is less than the other of the plies by a predetermined amount forming an overlap band in the other plies;
• b) stacking the first plies together such that the plies with greater width than the ply which has a smaller width provide an overlap with respect to the band having the greater width;
• c) warp/knitting a plurality of second plies of a fiber material and where one of the second plies has a width which is smaller than the other of the second plies by a predetermined amount forming an overlap band in the other of the second plies;
• d) stacking the second plies together such that the second plies with greater width than the second ply which has a smaller width provide an overlap with respect to the second ply having the greater width;
• e) laying the first and second stacks in side by side relationship with one overlap of the first stack being juxtaposed to one overlap of the second stack;
• and
• f) introducing the first and second stacks in such side by side relationship into a warp/knit machine and sewing or knitting the same together.

An apparatus for producing a thick multi-ply warp/knitted structural fabric sheet which is non-woven and non-crimped and which sheet can be used in structural applications, said apparatus comprising:

• a) a moving belt;
• b) support pins on said belt;
• c) a first ply application station for applying a unidirectional controlled orientation ply of parallel non-overlapping fibers with individual fiber tow tension control to the belt;
• d) a plurality of subsequent ply application stations for applying a plurality of plies to one another in facewise multi-axial engagement and where at least one of said plies is at a different angular relationship than other of said plies to form a fabric sheet;
• e) a pre-stabilization station for laying fibers in a 0.degree. orientation in parallel non-overlapping relation and joining the fibers together by a joining material to form a 0.degree. pre-stabilized ply;
• f) a 0.degree. ply application station for applying the 0.degree. pre-stabilized ply of fibers in facewise engagement with one of the other plies, the 0.degree. ply application station being located between the pre-stabilization station and at least one of the subsequent stations for applying a 0.degree. ply in a position other than on an upper surface of said fabric sheet.

A warp/knit multi-ply structural fabric sheet which is capable of being used in structural applications and which can be made on a low costs basis, said sheet comprising:

• a) at least one ply of a 0.degree. fiber orientation;
• b) a plurality of random fibers disposed on said ply of 0.degree. orientation;
• and
• c) a third outer ply located on said random fibers and being stitched thereto to form a three layer structural fabric sheet.