Method for making an anti-static tire tread

Abstract

A method of providing an extruded tire tread (T) with anti-static properties. In this method, a pin ( 10 ) is coated with an electrically conductive material (M). The coated pin ( 10 ) pierces the tire tread (T) to form an opening ( 12 ) of the desired depth and then is withdrawn. During withdrawal of the pin ( 10 ), the material (M) remains in the pierced opening ( 12 ) so that a conductive body ( 14 ) is formed in the tire tread (T). The pin ( 10 ) can then be re-coated with the material (M) and the cycle repeated to produce a plurality of conductive bodies ( 14 ) in the tire tread (T).

1 . A method for making an antistatic tire tread, said method comprising the steps of: 
 coating a pin with an electrically conductive material;    piercing an extruded tire tread with the coated pin to form an opening; and    withdrawing the pin from the now-formed opening in the tire tread;    wherein the material remains within the opening during the withdrawing step so that an electrically conductive body is formed in the tire tread.    
     
     
         2 . A method as set forth in  claim 1 , wherein the electrically conductive material is a liquid.  
     
     
         3 . A method as set forth in  claim 2 , wherein the liquid electrically conductive material forms an electrically conductive body upon evaporation.  
     
     
         4 . A method as set forth in  claim 3 , wherein the electrically conductive material comprises a carbon black mix in a volatile liquid and wherein the volatile liquid evaporates to form the electrically conductive body in the tire tread.  
     
     
         5 . A method as set forth in  claim 1 , wherein the electrically conductive material is a dry mixture.  
     
     
         6 . A method as set forth in  claim 4 , wherein the electrically conductive material is a powder.  
     
     
         7 . A method as set forth in  claim 6 , wherein the powder comprises a carbon black mix.  
     
     
         8 . A method as set forth in  claim 1 , further comprising the step of re-coating the pin with the material and then repeating the piercing and withdrawing steps.  
     
     
         9 . A method as set forth in  claim 8 , comprising continuously repeating the re-coating, piercing and withdrawing steps.  
     
     
         10 . A method as set forth in  claim 1 , wherein the piercing step is performed on a central region of the tire tread.  
     
     
         11 . A method as set forth in  claim 10 , wherein the piercing step is performed so that the electrically conductive body can form a continuous electrical path between a rolling surface and a carcass of a tire.  
     
     
         12 . A method as set forth in  claim 1 , wherein the piercing step is performed so that the electrically conductive body can form a continuous electrical path between a rolling surface and a carcass of a tire.  
     
     
         13 . A method as set forth in  claim 1 , further comprising the steps of sequentially coating a plurality of pins with the electrically conductive material, sequentially piercing the tire tread with the coated pins to form openings, and sequentially withdrawing the pins.  
     
     
         14 . A method as set forth in  claim 8 , wherein said piercing and withdrawing steps are performed by mounting the plurality of pins on a wheel.  
     
     
         15 . A method as set forth in  claim 14 , wherein the wheel is turned by movement of the tire tread.  
     
     
         16 . A method as set forth in  claim 15 , wherein said plurality of pins are mounted on a circumference of the wheel at fixed distances so that turning of the wheel will cause the pins to pierce the tire tread at regular intervals.  
     
     
         17 . A method as set forth in  claim 16 , wherein the pins are arranged in a single row.  
     
     
         18 . A method as set forth in  claim 16 , wherein the pins are arranged in a plurality of rows.  
     
     
         19 . A method as set forth in  claim 18 , wherein the pins are transversely aligned.  
     
     
         20 . A method as set forth in  claim 18 , wherein the pins are transversely staggered.  
     
     
         21 . A machine for performing the method of  claim 14 , said machine comprising: 
 a wheel on which the pins are mounted;    a frame which positions the wheel adjacent a conveyor for the tire tread; and    a supply system which coats the pins with the electrically conductive material.    
     
     
         22 . A machine as set forth in  claim 21 , wherein movement of the tire tread on the conveyor causes the wheel to turn.  
     
     
         23 . A machine as set forth in  claim 21 , wherein the pins are fixedly mounted to an adapter rim attached to the wheel.  
     
     
         24 . A machine as set forth in  claim 23 , wherein the pins comprise distal portions of posts which are friction fit into openings in the rim.  
     
     
         25 . A machine as set forth in  claim 23 , wherein the pins comprise distal portions of screws which threaded into openings in the rim.  
     
     
         26 . A machine as set forth in  claim 23 , wherein the pins are arranged in a single row.  
     
     
         27 . A method as set forth in  claim 23 , wherein the pins are arranged in a plurality of rows.  
     
     
         28 . A method as set forth in  claim 27 , wherein the pins are transversely aligned.  
     
     
         29 . A method as set forth in  claim 27 , wherein the pins are transversely staggered.  
     
     
         30 . A method as set forth in  claim 27 , wherein the pins are textured to facilitate the coating process.  
     
     
         31 . A machine as set forth in  claim 21 , wherein the supply system comprises a transfer reel rotatably mounted to the frame by a spindle and wherein the spindle for the wheel is coupled to the spindle for the transfer reel so that turning of the wheel causes rotation of the transfer reel.