Method and apparatus for tire flaw detection

An apparatus for detecting a flaw in a tire, comprising:

• a voltage generator producing a high voltage pulse at a first frequency less than a predetermined threshold frequency;
• an electrical conductor receiving the high voltage pulse and oriented with respect to the tire to establish an electric field within the tire;
• means for effecting relative movement between the tire and the electrical conductor such that an electric arc extends from the electric field through the flaw when the flaw is proximate the electric field;
• and
• a flaw detection circuit capacitively coupled to the electrical conductor and receiving a signal indicative of a voltage signal on the electrical conductor, and including means for determining if the frequency of the received signal is greater than the threshold frequency, and means for determining if the amplitude of the received signal is greater than a predetermined value, and if both conditions are met, producing an indicator signal indicating the presence of the flaw.

A method for detecting a flaw in a tire, the method comprising:

• placing an electrical conductor within the tire;
• applying a high voltage pulse at a first frequency to the electrical conductor;
• effecting relative movement between the tire and the electrical conductor such that when a flaw is located between the electrical conductor and an electrical ground, an arc is generated in response to the presence of the flaw;
• and
• detecting if the frequency of a voltage signal on the electrical conductor is above a predetermined threshold frequency, and if so, indicating the presence of the flaw.