Bristles having varying stiffness

Abstract

Bristle stiffness is varied by allowing a support beam that carries the bristles to undergo torsional movement in response to brushing action. Torsional movement is achieved by allowing the support beam to be disconnected to the brush head along at least portions of the length of the support beam. In particularly preferred embodiments, brushes employing the varying stiffness techniques are made with bristle sub-assemblies that have at least one row of bristles connected to a base string or similar structure that functions as a support beam. The base string can be connected across an opening in the brush, and is thus connected at its opposite ends, or it can be connected at any number of spaced intervals, the number and length of spacing being selected to achieve a desired degree of stiffness.

What is claimed is:  
     
         1 . A bristle sub-assembly comprising: 
 at least one row of bristles, the bristles having proximal ends and distal ends; and    a coating disposed on at least the proximal end portions of the bristles, the coating having mechanical properties selected to stiffen the distal ends of the bristles.    
     
     
         2 . A bristle sub-assembly according to  claim 1 , wherein the coating is made of an elastomeric resin.  
     
     
         3 . A bristle sub-assembly according to  claim 1 , wherein the proximal ends of the bristles are connected to a support beam.  
     
     
         4 . A bristle sub-assembly according to  claim 1 , wherein the coating covers at least a portion of the proximal end portions of the bristles.  
     
     
         5 . A bristle sub-assembly according to  claim 1 , wherein the support beam is selected from the group consisting of a glue line, a base string, and a bond area consisting of melted bristle material.  
     
     
         6 . A bristle sub-assembly according to  claim 1 , wherein the coating is made of a material selected to provide additional functionally selected from the group consisting of wear indication and therapeutic properties such as a batericide.