Expanded metal and process of making the same

Abstract

An expanded metal is provided including a plurality of integral strands defining diamond shapes, each diamond shape having a long dimension as measured from two opposing vertices and a short dimension, generally transverse to the long direction, as measured between two other opposing vertices, such that the long dimension is less than twice the short dimension.

What is claimed is: 
     
         1 . An expanded metal comprising a plurality of integral strands defining diamond shapes, each diamond shape having a first dimension as measured from two opposing vertices and a second dimension, generally transverse to the first dimension, as measured between two other opposing vertices, wherein said expanded metal is formed by slitting a sheet of metal thereby preliminary expanding said metal, wherein said slit preliminary expanded metal having been further expanded after slitting along a direction by at least 15% per linear dimensional unit to form said expanded metal, and wherein the second dimension is along the direction of expansion. 
     
     
         2 . The expanded metal of  claim 1  wherein the second dimension is equal to the first dimension. 
     
     
         3 . The expanded metal of  claim 1  wherein each vertex is expanded beyond in plastic yield point. 
     
     
         4 . The expanded metal of  claim 1  wherein each strand has a width of 0.017 inch. 
     
     
         5 . The expanded metal of  claim 1  wherein the first dimension is less than twice the second dimension. 
     
     
         6 . The expanded metal of  claim 1  wherein the second dimension is about equal to the first dimension. 
     
     
         7 . The expanded metal of  claim 1  wherein said strands have been expanded beyond their plastic yield point. 
     
     
         8 . The expanded metal of  claim 1  wherein the slit preliminary expanded metal has been expanded along the direction by at least 25% per linear dimensional unit. 
     
     
         9 . The expanded metal of  claim 1  wherein the slit preliminary expanded metal has been expanded along the direction by at least 28% per linear dimensional unit. 
     
     
         10 . The expanded metal of  claim 1  wherein the slit preliminary expanded metal has been expanded along the direction by at least 30% per linear dimensional unit. 
     
     
         11 . The expanded metal of  claim 1  wherein after slitting the slit preliminary expanded metal first dimension is decreased by at least 15%. 
     
     
         12 . The expanded metal of  claim 1  wherein after slitting the slit preliminary expanded metal first dimension is decreased by at least 18.8%. 
     
     
         13 . An expanded metal formed by slitting a sheet of metal thereby preliminary expanding said metal and then further expanding said slit preliminary expanded metal along a direction, said slit preliminary expanded metal comprising a plurality of integral strands defining diamond shapes, each diamond shape having a first dimension as measured from two opposing vertices and a second dimension, generally transverse to the first direction, as measured between two other opposing vertices, wherein the second direction is along the direction of expansion, and wherein after slitting, the slit preliminary expanded metal first dimension is decreased by at least 15%. 
     
     
         14 . The expanded metal of  claim 13  wherein the first dimension is less than twice the second dimension. 
     
     
         15 . The expanded metal of  claim 13  wherein the second dimension is about equal to the first dimension. 
     
     
         16 . The expanded metal of  claim 13  wherein said strands have been expanded beyond their plastic yield point. 
     
     
         17 . The expanded metal of  claim 13  wherein after slitting, the slit preliminary expanded metal first dimension is decreased by at least 18%. 
     
     
         18 . The expanded metal of  claim 13  wherein after slitting, the slit preliminary expanded metal first dimension is decreased by at least 18.8%. 
     
     
         19 . The expanded metal of  claim 13  wherein after slitting, the slit preliminary expanded metal first dimension is decreased by at least 20%. 
     
     
         20 . The expanded metal of  claim 13  wherein after slitting, the slit preliminary expanded metal first dimension is decreased by at least 23%. 
     
     
         21 . The expanded metal of  claim 13  wherein the slit preliminary expanded metal has been further expanded along the direction by at least 25% dimensional unit. 
     
     
         22 . A filter comprising a filter medium reinforced with an expanded metal, wherein said reinforced filter medium and said expanded metal are pleated, wherein said expanded metal is formed by slitting a sheet of metal preliminary expanding said metal and then further expanding said slit metal along a direction, said slit preliminary expanded metal comprising a plurality of integral strands defining diamond shapes, each diamond shape having a first dimension as measured from two opposing vertices and a second dimension, generally transverse to the first direction, as measured between two other opposing vertices, wherein the second direction is along the direction of expansion, and wherein after slitting, the slit preliminary expanded metal first dimension is decreased by at least 15%. 
     
     
         23 . The filter of  claim 22  wherein the first dimension is less than twice the second dimension. 
     
     
         24 . The filter of  claim 22  wherein the second dimension is about equal to the first dimension. 
     
     
         25 . The filter of  claim 22  wherein said strands have been expanded beyond their plastic yield point. 
     
     
         26 . The filter of  claim 22  wherein after slitting, the slit preliminary expanded metal first dimension is decreased by at least 18%. 
     
     
         27 . The filter of  claim 22  wherein after slitting, the slit preliminary expanded metal first dimension is decreased by at least 18.8%. 
     
     
         28 . The filter of  claim 22  wherein after slitting, the slit preliminary expanded metal first dimension is decreased by at least 20%. 
     
     
         29 . The filter of  claim 22  wherein after slitting, the slit preliminary expanded metal first dimension is decreased by at least 23%. 
     
     
         30 . The filter of  claim 22  wherein the slit preliminary expanded metal has been further expanded along the direction by at least 25% per linear dimensional unit. 
     
     
         31 . The filter of  claim 22  wherein after being pleated said expanded metal does not spring back toward its unpleated position. 
     
     
         32 . A filter comprising a filter medium reinforced with an expanded metal, wherein said reinforced filter medium and said expanded metal are pleated, wherein said expanded metal is formed by slitting a sheet of metal by a die and then expanding said slit metal along a direction, said expanded metal comprising a plurality of integral strands defining diamond shapes, each diamond shape having a first dimension as measured from two opposing vertices and a second dimension, generally transverse to the first direction, as measured between two other opposing vertices, wherein when pleated said expanded metal does not spring back towards an unpleated position.