Papermakers fabric with orthogonal machine direction yarn seaming loops

Abstract

A flat woven pin-seamed papermakers fabric wherein machine direction yarns define a series of seaming loops on the opposing fabric ends. The fabric comprises a system of flat monofilament machine direction warp yarns (hereinafter MD yarns) which are woven in a selected weave construction. In a preferred embodiment, the system of MD yarns comprises upper and lower yarns which are vertically stacked. Selected end segments of the upper and lower MD yarns are removed and yarn segments made of a more durable material are rewoven into the fabric end in the space vacated by the trimmed upper and lower MD yarn end segments. Non-loop forming upper MD yarns are preferably backwoven into the space vacated by trimming respective lower MD yarns. Preferably, at least the upper MD yarns are woven contiguous with each other to lock in the machine direction alignment of the stacking pairs of MD yarns and the orthogonal orientation of the end loops. The seaming loops of the opposing ends are intermeshed and joined via a pintle yarn. The permeability of the seam area is controlled via the inserting of rectangular stuffer yarns parallel to the pintle yarn.

What I claim is: 
     
       1. A papermakers fabric comprising a system of .Iadd.monofilament .Iaddend.MD yarns interwoven with a system of CMD yarns to define a body and opposing end portions of the fabric and a series of end loops formed on said opposing end portions, wherein selected end loops are made of yarn segments having the same geometric cross-section, but are made of a different material than the MD yarns which define said fabric body; and said yarn segments are interwoven into an end portion of the papermakers fabric in spaces vacated by trimming selected MD yarns back a selected distance within the end portion of the fabric, and do not extend into said fabric body, wherein the ends of the trimmed yarns and the ends of the selected end loop forming yarn segments all terminate on a common side of the fabric which is opposite to a paper carrying side of the fabric. 
     
     
       2. A papermakers fabric according to claim 1 wherein the system of MD yarns comprises pairs of upper and lower flat monofilament yarns and the yarn segments which form said selected end loops interweave in spaces vacated by respective pairs of upper and lower MD yarns which have been trimmed back within the fabric end portion. 
     
     
       3. A papermakers fabric according to claim 2 wherein said CMD yarns system is a single layer of CMD yarns. 
     
     
       4. A papermakers fabric according to claim 1 wherein said loop forming yarn segments are made of polyetheretherketone (PEEK). 
     
     
       5. A papermakers fabric according to claim 1 wherein said yarn segments are made of a material more durable than said MD yarns which define said fabric body. 
     
     
       6. A papermakers fabric according to claim 1, wherein each said end portion is approximately 2 inches in length in the machine direction. 
     
     
       7. A papermakers fabric comprising a system of .Iadd.monofilament .Iaddend.MD yarns interwoven with a system of CMD yarns to define a body and opposing end portions of the fabric and a series of end loops formed on said opposing end portions, wherein selected end loops are made of yarn segments having the same geometric cross-section, but are made of a different material than the MD yarns which define said fabric body; and said yarn segments are interwoven into an end portion of the papermakers fabric in spaces vacated by trimming selected MD yarns back a selected distance within the end portion of the fabric, and do not extend into said fabric body, wherein said opposing series of end loops are intermeshed to define a seam area having . .intersection.!. .Iadd.intersecting .Iaddend.and non-intersecting areas, the fabric further comprising: a pintle yarn disposed within the intersecting area of said intermeshed loops; and   a stuffer yarn disposed within the non-intersecting area of each of said series of intermeshing loops parallel with said pintle yarn.   
     
     
       8. A papermakers fabric according to claim 7 wherein both said MD yarns and said stuffer yarns have a non-circular cross-section. 
     
     
       9. A papermakers fabric according to claim 7 wherein the permeability of the seam area is within 10 cfm of the permeability of said body of the fabric. 
     
     
       10. A papermakers fabric having opposing ends comprising: a system of flat monofilament MD yarns interwoven with a system of CMD yarns to define a fabric body;   a series of end loops formed on each opposing end of said fabric body from yarns which are interwoven in at least the end of the fabric body wherein at least some of the end loops are formed from selected MD yarns which are looped back and interwoven with said CMD yarns directly beneath themselves; and   selected end loops are made of a material which is more durable than the material of which at least 50% of the MD yarns are made.   
     
     
       11. A papermakers fabric according to claim 10 wherein said selected end loops are made of polyetheretherketone and said at least 50% of MD yarns are made of polyester. 
     
     
       12. A papermakers fabric according to claim 10 wherein at least some of the end loops which are made of said more durable material are formed from yarn segments which are interwoven into spaces vacated by trimming selected MD yarns back into the fabric body. 
     
     
       13. A papermakers fabric according to claim 10 wherein said system of CMD yarns is a single layer of CMD yarns. 
     
     
       14. A papermakers fabric comprising a system of .Iadd.monofilament .Iaddend.MD yarns interwoven with a system of CMD yarns to define a body and opposing end portions of the fabric and a series of end loops formed on said opposing end portions, wherein selected end loops are made of yarn segments having the same geometric cross-section, but are made of a different material than the MD yarns which define said fabric body; and said yarn segments are interwoven into an end portion of the papermakers fabric in spaces vacated by trimming selected MD yarns back a selected distance within the end portion of the fabric, and do not extend into said fabric body, wherein at least some of the end loops are formed from the MD yarns which define said fabric body. 
     
     
       15. A method of forming seaming loops for a papermakers fabric comprising: interweaving MD warp yarns with CMD weft yarns in a repeated pattern which defines a selected crimp in the MD yarns to define a fabric body having two sides along the machine direction and two ends, all of the MD warp yarns having the same geometric cross-section and at least one of said MD warp yarns woven proximate a side of the fabric body being made of a different material than the other MD warp yarns;   trimming back selected MD warp yarns a selected distance from at least one of said fabric ends;   removing said different material warp yarn from the side of the fabric body; and   using segments of said different material warp yarn to form seaming loops by interweaving said yarn segments into spaces vacated by said trimming said selected MD yarns.   
     
     
       16. The method according to claim 15 further comprising selecting a material for said different material warp yarn which is more durable than the material from which said other MD warp yarns are made. .Iadd.17. A method of forming seaming loops for a papermakers fabric comprising interweaving MD warp yarns with CMD weft yarns in a repeated pattern to define a fabric body having two sides along the machine direction and two ends, all of the MD warp yarns having the same geometric cross-section, trimming back selected MD warp yarns a selected distance from at least one of said fabric ends, and using segments of yarns having a predetermined crimp to form seaming loops by interweaving said yarn segments into spaces vacated by said trimming said selected MD yarns, characterized in that: at least one of said MD warp yarns woven proximate a side of the fabric body being made of a different material than the other MD warp yarns;   removing said different material warp yarn from the side of the fabric body; and   using selected portions of said removed yarns as said yarn segments.   
     
     
        .Iaddend..Iadd.18.  The method according to claim 17 further comprising selecting a material for said different material warp yarn which is more durable than the material from which said other MD warp yarns are made. .Iaddend.