Magnetic sensor for determining wear

A method for determining wear experienced by an object, comprising the steps of:

• interposing an elongated magnet having a first length along a long dimension thereof, a first long flat side and an opposing second long flat side between a first magnetically permeable material having a second length and a flat side disposed alongside the first long flat side of the magnet, and a second magnetically permeable material having a third length and a flat side disposed alongside the second long flat side of the magnet, wherein the second length and the third length are greater than the first length, forming thereby a closed end and an air gap between the first magnetically permeable material the second magnetically permeable material at the opposing end;
• exposing the closed end to the same wear as experienced by the object;
• and
• measuring the magnetic field within the air gap;
• whereby the magnetic field in the air gap decreases as the magnet, the first material and the second material are worn away at the closed end.

A wear sensor comprising in combination:

• an elongated magnet having a first length along a long dimension thereof, a long flat side, and a pole direction parallel to the flat side;
• a first magnetically permeable material having a second length and a flat side disposed alongside the flat side of said magnet;
• a second magnetically permeable material having a third length and a flat side disposed alongside the long flat side of said magnet, wherein the second length and the third length are less than the first length, wherein said magnet and said first magnetically permeable material form a first closed end, wherein said magnet and said second magnetically permeable material form an opposing second closed end, and wherein said first magnetically permeable material and said second magnetically permeable material form an air gap therebetween on the flat side of said magnet;
• and
• means for measuring the magnetic field within the air gap;
• whereby the magnetic field in the air gap decreases as said magnet, and said first magnetically permeable material are worn away at the first closed end.

A wear sensor comprising in combination:

• an elongated magnet having a first length along a long dimension thereof, a long flat side, and a pole direction parallel to the first flat side;
• a magnetically permeable material having a second length and a flat side disposed alongside the long flat side of said magnet, wherein the second length is greater than the first length, forming thereby a closed end and an opposing end wherein said magnetically permeable material extends beyond the flat side of said elongated magnet;
• and
• means for measuring the magnetic field in the vicinity of the extended magnetically permeable material;
• whereby the magnetic field in vicinity of the extended magnetically permeable material decreases as said magnet and said magnetically permeable material are worn away at the closed end.