Patent Publication Number: US-2005122023-A1

Title: Shock Resistant Spark Plug

Description:
Ordinary spark plugs use a breakable ceramic to insulate the spark plug electrode core from grounding without creating an arc through its gap. One problem with this material is that it does not handle thermal or mechanical shock very well and can be easily broken by a sharp blow, cold water, or a socket wrench. Broken or cracked ceramic insulators can leak their charge to ground before creating an arc through their gap and become useless. Even worse, fragments of the hard ceramic can fall down into the cylinder and cause major damage to pistons, valves, and cylinder walls if the ceramic is accidentally broken by a socket wrench or other such tool. 
    
    
      Our Invention solves both of these problems by surrounding the ceramic electrode insulator with a layer of non-conductive material that can better withstand thermal and mechanical shock. Furthermore, the non-conductive material will contain fragments of ceramic if forces (such as those from a wrench) happen to break the ceramic inside.  
      A preferred fit of the material will completely envelope the ceramic insulator or electrode shaft from the threaded metal chassis to the plug wire connector in such a way as to prevent fragments of broken ceramic from escaping the material. One way to accomplish this is to fit or mold the material onto or over the threaded metal chassis.