Leydig, Voit & Mayer
Igniter plug with vibration damping means
 An igniter plug having a center conductor, an insulator and a conductive outer shell. The insulator surrounds and supports the center conductor axially within the shell along a substantial portion of the length of the center conductor. The insulator is of reduced diameter toward the discharge end of the igniter and terminates short of the full length of the center conductor. The center conductor extending beyond the insulator terminates short of the discharge end of the igniter and has a discharge electrode of greater diameter than the center conductor affixed to the center conductor end. The electrode terminates at the discharge end of the igniter. A helical compression spring is fitted over the center conductor between the end of the insulator and the electrode to absorb vibrations of the center conductor and electrode. 
Unison Industries Limited Partnership
Helmut P.
Meyer