Direct Tension Indicating Washers

Abstract

A direct tension indicating washer including: a first surface having a discrete protuberance formed thereon; a second surface having a discrete indentation formed opposite the protuberances; and an indicating material positioned in the indentation, wherein the indicating material has a cured skin on an outside of the indicating material and a compressible, liquid core in an interior of the indicating material. When the bolt tension reaches a predetermined level, the liquid cores erupts through the cured skin causing a climactic and dramatic appearance of the indicating material about an edge of the washer.

1 . A direct tension indicating washer comprising:
 a first surface having a discrete protuberance formed thereon;   a second surface having a discrete indentation formed opposite the protuberance; and   an indicating material positioned in the indentation, wherein the indicating material has a cured skin on an outside of the indicating material and a liquid core in an interior of the indicating material.   
   
   
       2 . The direct tension indicating washer of  claim 1  wherein the indicating material is mixed under nitrogen prior to being polymerized. 
   
   
       3 . The direct tension indicating washer of  claim 1  wherein the indicating material is mixed under ultra-dry air prior to being polymerized. 
   
   
       4 . The direct tension indicating washer of  claim 1  wherein the cured skin is formed by initiating polymerization of the indicating material and terminating the polymerization upon formation of the cured skin. 
   
   
       5 . The direct tension indicating washer of  claim 4  wherein polymerization is terminated by applying energy to the indicating material. 
   
   
       6 . The direct tension indicating washer of  claim 5  wherein the indicating material includes a platinum based catalyst. 
   
   
       7 . The direct tension indicating washer of  claim 1  wherein cured skin is a fast curing skin deposited on top of the liquid core indicating material. 
   
   
       8 . The direct tension indicating washer of  claim 1  further comprising a channel leading from the indentation to an outer diameter of the direct tension indicating washer. 
   
   
       9 . The direct tension indicating washer of  claim 1  wherein:
 the first surface has a plurality of discrete protuberances formed thereon;   the second surface has a plurality of discrete indentations, each indentation formed opposite one of the protuberances; and   a plurality of channels formed in the second surface, each channel leading from one of the indentations to an outer diameter of the direct tension indicating washer