Patent Publication Number: US-6706376-B1

Title: Textile mesh structure, in particular, a geotextile

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a U.S. National Stage Application of International Application No. PCT/EP00/02395 filed Mar. 17, 2000 and claims priority under 35 U.S.C. §119 of German Patent Application No. 199 15 722.7 filed Apr. 8, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a textile mesh structure, in particular a geomesh, comprising linearly extending warp threads and weft threads which extend linearly substantially at a right angle to the warp threads and which are joined to the warp threads by means of fixing threads which are applied by warp knitting and the meshes of which extend around the warp threads over the entire length and the weft threads in the region of the intersections, wherein the warp threads and the weft threads are arranged individually or in groups at relatively large spacings which produce the internal widths of the mesh. 
     2. Discussion of Background Information 
     Textile mesh structures of that kind are known from U.S. Pat. Nos. 4,472,086 and 4,540,311. The linearly extending and load-carrying warp threads and weft threads of the mesh preferably comprise high-module polyester yarns or other high-strength filament yarns, for example of polyamide. The fixing thread which is knitted onto the structure and which joins the warp threads to the weft threads in the form of knitted meshes or tricot meshes is considerably weaker in terms of its thread strength than the warp threads and the weft threads. 
     If necessary that mesh structure after manufacture thereof is encased with a soft plastic material, for example PVC, with a bitumen emulsion or with latex. 
     SUMMARY OF THE INVENTION 
     The present invention provides a better join between the warp threads and the weft threads without requiring additional fixing threads or stronger fixing threads. 
     In accordance with the invention, in the regions in which the weft threads cross the warp threads, the lengths of the meshes of the fixing threads are markedly shorter than in the regions which are therebetween. 
     Advantageously, the length of the meshes of the fixing threads in the regions in which the weft threads cross the warp threads is at least 30% shorter than the length of the meshes between the intersection regions. That measure provides for a considerable saving in terms of fixing threads or fixing yarn without any fear of an adverse influence on the strength of the mesh structure. The manufacturing speed of those textile mesh structures is also increased. 
     The present invention is directed to a textile mesh structure including linearly extending warp threads, linearly extending weft threads positioned substantially at a right angle to the warp threads, and fixing threads arranged to join the warp and weft threads. The fixing threads are applied by warp knitting to form a thread meshes, and the thread meshes are arranged to extend around the warp threads over an entire length of the warp threads and around the weft threads in a region in which the warp threads and weft threads intersect. The warp threads and the weft threads are arranged one of individually or in groups at relatively large spacings in order to form internal widths. In the regions in which the warp thread and the weft threads intersect, lengths of the thread meshes are shorter than in regions between the intersect regions. 
     According to a feature of the invention, the textile mesh is structured as a geomesh. 
     Further, the lengths of the thread meshes in the intersect regions are at least 50% shorter than the lengths of the meshes between the intersect regions. 
     In the intersect region, the lengths of the thread meshes are structured and arranged such that a mesh is associated with each weft thread. Moreover, the weft threads are arranged in weft thread groups including a plurality of weft threads, and the lengths of the thread meshes are structured and arranged such that a mesh is associated with each weft thread of the weft thread group. 
     According to another feature of the invention, a fixing thread is associated with each warp thread to form a warp mesh. 
     The warp threads are arranged in warp groups including at least two warp threads positioned in closer relation to each other than to adjacent warp groups. Further, a joining thread is arranged in a zig-zag configuration to prevent lateral displacement of the warp threads of the warp group. The fixing threads of the warp group are associated with each warp thread. Moreover, the joining thread extends in a zig-zag configuration to prevent lateral displacement of the fixing threads. 
     According to still another feature of the instant invention, a non-woven material layer is included, and one of the joining threads and the fixing threads are one of knitted on applied by Raschel knitting to join the warp and the weft threads to the non-woven material layer. 
     The present invention is directed to a process for forming a textile mesh structure including linearly extending warp threads, linearly extending weft threads at substantially a right angle to the warp threads, and warp knitting fixing threads to join the warp and weft threads, such that thread meshes are formed. The thread meshes are arranged to extend around the warp threads over an entire length of the warp threads and around the weft threads in a region in which the warp threads and weft threads intersect, and, in the regions in which the warp thread and the weft threads intersect, lengths of the thread meshes are formed to be shorter than in regions between the intersect regions. 
     According to a feature of the instant invention, the warp threads and the weft threads are arranged one of individually and in groups, such that, spacing between threads in a group is smaller than spacing between adjacent groups. 
     In accordance with another feature of the invention, the process includes arranging a joining thread in a zig-zag configuration to prevent lateral displacement of the warp threads of a warp group. 
     Moreover, the process includes arranging a joining thread in a zig-zag configuration to prevent lateral displacement of the fixing threads. 
     In accordance with still yet another feature of the present invention, the process includes joining the warp and weft threads to a non-woven material layer. Further, the joining includes one of knitting on and applying by Raschel knitting. 
     Further features of the invention are set forth in the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention is described in greater detail in the description hereinafter with reference to the drawings in which: 
     FIG. 1 is a diagrammatic view of the textile mesh structure, in accordance with the invention, 
     FIG. 2 is a view on an enlarged scale of a register round or repeat of the mesh structure from one side, and 
     FIG. 3 is a view on an enlarged scale of a register round or repeat of the mesh structure from the other side. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The textile mesh structure shown in FIG. 1 is composed of linearly extending warp threads  1  and weft threads  2  which extend at a right angle to the warp threads  1 . Each three warp threads  1  are combined to form a respective warp thread group  9 . In addition each two weft threads  2  are combined to form a respective weft thread group  11 . The weft threads  2  are joined to the warp threads  1  by means of fixing threads  3  which are knitted thereon. The meshes of the fixing threads  3  extend in a zig-zag configuration over the warp threads  1 . The warp thread groups  9  and the weft thread groups  11  are arranged at relatively large spacings which afford the internal widths  5  of the mesh  6 . 
     In accordance with the invention, in the regions  4  in which the weft threads  2  cross the warp threads  1 , the lengths  8 ′ of the meshes  7 ′ of the fixing threads  3  are markedly shorter than in the regions therebetween of the mesh structure. 
     As FIGS. 2 and 3 in particular show the lengths  8 ′ of the meshes  7 ′ or the threads loops of the fixing threads  3  in the regions  4  in which the weft threads  2  intersect the warp threads  1  are at least 30% and preferably 50% shorter than the lengths  8  of the meshes  7  between the intersection regions  4 . In the intersection regions  4 , a mesh  7 ′ of the fixing threads  3  can be associated with each weft thread  2  per warp thread  1 . 
     So that the warp threads  1  are secured to prevent lateral displacement thereof, a joining yarn  10  is applied by a Raschel knitting procedure, for holding the warp threads  1  of a warp thread group  9  together or securing them to prevent lateral displacement. That joining yarn  10  can either extend around the warp threads  1  of a warp thread group  9  in a zig-zag configuration or, as shown in FIGS. 2 and 3, the fixing threads  3  of each warp thread group  9 . It is however also possible for the warp threads  1  of a warp thread group  9  to be secured to prevent lateral displacement by the fixing threads  3  of a warp thread group  9  changing by tricot thread laying from one warp thread  1  of a warp thread group  9  to the adjacent warp thread  1  of the same warp thread group  9 . 
     The textile mesh structure according to the invention can also be combined in known manner with a non-woven material layer. 
     LIST OF REFERENCES 
       1  warp threads 
       2  weft threads 
       3  fixing threads 
       4  intersection region 
       5  internal width 
       6  mesh structure 
       7  mesh 
       7 ′ mesh in the region of the intersection  4   
       8  length of the mesh  7   
       8 ′ length of the mesh  7 ′ 
       9  warp thread group 
       10  joining yarn 
       11  weft thread group