Microstructured high friction surface for high friction to fabric, yarn and fibers

Abstract

This invention is directed to an improved contact surface for manipulating fabrics wherein the microstructure included on the contact surface having a plurality of pillars spaced apart in the range of 200 μm and 600 μm, having a height in the range of 50 μm and 1200 μm, a width of in the range of 70 μm and 300 μm, a wall draft angle between 0° and 15°, a density of in the range of 5,000 to 20,000 pillars per square inch, and a friction rating greater than 7. The contact surface can be included on a sewing machine feed dog, a glove, sporting equipment, firearm grip, hand rail, tools, and a strap such as for a satchel or backpack.

What is claimed is: 
     
         1 . A fabric contact surface on an article for manipulating fabric comprising:
 a contact surface;   a microstructure included on the contact surface having a plurality of pillars spaced apart between 200 μm and 600 μm, having a height between 50 μm and 1200 μm, a width of between 70 μm and 300 μm, a wall draft angle between 0° and 15°, a density of between 5,000 to 20,000 pillars per square inch, and a friction rating greater than 7.   
     
     
         2 . The apparatus of  claim 1  including a first row of pillars arranged in an offset configuration with a second row of pillars. 
     
     
         3 . The apparatus of  claim 1  wherein the width is in the range of 90 μm and 110 μm. 
     
     
         4 . The apparatus of  claim 1  wherein the height is in the range of 90 μm and 110 μm. 
     
     
         5 . The apparatus of  claim 1  wherein the pillars have a pitch in in the range of 325 μm and 375 μm. 
     
     
         6 . The apparatus of  claim 1  wherein the pillars have a square cross-section. 
     
     
         7 . The apparatus of  claim 1  including a circular base included in each pillar. 
     
     
         8 . The apparatus of  claim 1  having a friction force against fabric in a horizontal direction and substantially no friction force in a vertical direction. 
     
     
         9 . The apparatus of  claim 1  having a non-linear horizontal friction against the fabric. 
     
     
         10 . The feed dog of  claim 1  wherein the pillars are arranged in a triangular lattice. 
     
     
         11 . The apparatus of  claim 1  including a lubrication coating on the pillars. 
     
     
         12 . The feed dog of  claim 11  wherein the lubrication coating in taken from the group consisting of: silicone oils, petroleum oils, mineral oils, PVD coating, PTFE coatings, diamond-carbon coatings, nitride, and carbide coatings. 
     
     
         13 . A apparatus of  claim 1  wherein the pillars have an area in the range of 63 cm 2  and 242 cm 2 . 
     
     
         14 . The apparatus of  claim 1  wherein the contact surface is disposed on an article selected from the group consisting of: a feed dog, a glove, sporting equipment, rollers, tensioning rollers, firearm grip and a strap. 
     
     
         15 . The apparatus of  claim 14  wherein the microstructures are attached on a substrate and the substrate is attached to the article. 
     
     
         16 . The apparatus of  claim 14  wherein the strap is a backpack strap. 
     
     
         17 . A fabric contact surface on an article for manipulating fabric comprising:
 a contact surface; and,   a microstructure included on the contact surface having a plurality of pillars having a height in the range of 50 μm and 1200 μm, a width of in the range of 70 μm and 300 μm, a wall draft angle in the range of 0° and 15°, and a friction rating of 7 or greater against a fabric taken from the group consisting of cotton knit or polyester fabric.   
     
     
         18 . The apparatus of  claim 17  wherein the contact surface is disposed on an article selected from the group consisting of: a feed dog, a glove, sporting equipment, firearm grip and a strap. 
     
     
         19 . The apparatus of  claim 17  where the pillars are asymmetrical and have a trapezoid cross section. 
     
     
         20 . A fabric contact surface on an article for manipulating fabric comprising:
 a microstructure disposed on a contact surface wherein the contact surface is a surface on an article taken from the group consisting of: sewing feed dog, glove, grip, handle, strap, hand rail, tool, and sporting goods; and,   a plurality of pillars included in the microstructure wherein the pillars have an area in the range of 63 cm 2  and 242 cm 2  and a pitch in the range of 200 μm and 600 μm.   
     
     
         21 . The apparatus of  claim 20  wherein the microstructure is made from acrylonitrile butadiene styrene (ABS) and has a width of about 100 μm, pitch in the range of 200 μm to 350 μm, height in the range of 150 μm to 400 μm and static coefficient of in the range of 1.58 to 1.76 and dynamic coefficient in the range of about 1.29 to 1.74 when measured using a sled type test against a denim fabric.