Magnetic earth bit seal

Abstract

An earth bit seal includes a magnetic ring that determines how strongly the earth bit seal engages a lug and/or cone of an earth bit. The earth bit seal also includes a flexible ring positioned away from any dynamic sealing surfaces that engage the lug or cone. The flexible ring is positioned away from the dynamic sealing surfaces so that, if it becomes impregnated with debris, it will not act as an abrasive ring that undesirably removes material from them, or from the lug and cone.

1 . An earth bit seal assembly, comprising:
 a flexible ring; and   first and second rigid rings coupled together with the flexible ring, wherein the flexible ring allows the first and second rigid rings to move relative to each other.   
   
   
       2 . The assembly of  claim 1 , wherein the flexible ring allows the first and second rigid rings to move towards and away from each other. 
   
   
       3 . The assembly of  claim 1 , further including a first magnetic ring carried by the first rigid ring, wherein the flexible ring allows the first magnetic ring to move relative to the second rigid ring. 
   
   
       4 . The assembly of  claim 3 , wherein the flexible ring allows the first magnetic ring to move towards and away from the second rigid ring. 
   
   
       5 . The assembly of  claim 3 , further including a second magnetic ring carried by the first rigid ring, wherein the flexible ring allows the second magnetic ring to move relative to the first rigid ring. 
   
   
       6 . The assembly of  claim 5 , wherein the flexible ring allows the second magnetic ring to move towards and away from the first rigid ring. 
   
   
       7 . An earth bit, comprising:
 a lug and cutting cone rotatably coupled together;   a flexible ring; and   a seal assembly which includes first and second rigid rings coupled together with the flexible ring, wherein the seal assembly is repeatably moveable between flexed and unflexed conditions.   
   
   
       8 . The earth bit of  claim 7 , wherein the flexible ring is repeatably moveable between stretched and unstretched conditions. 
   
   
       9 . The earth bit of  claim 7 , wherein the flexible ring does not form a dynamic sealing surface with the lug or cutting cone. 
   
   
       10 . The earth bit of  claim 7 , wherein the flexible ring allows the first and second rigid rings to move relative to each other. 
   
   
       11 . The assembly of  claim 7 , wherein the flexible ring allows the first and second rigid rings to move towards and away from each other. 
   
   
       12 . The assembly of  claim 7 , further including a first magnetic ring which couples the first rigid ring to the lug, wherein the flexible ring allows the first magnetic ring to move relative to the second rigid ring. 
   
   
       13 . The assembly of  claim 12 , wherein the flexible ring allows the first magnetic ring to move towards and away from the second rigid ring. 
   
   
       14 . The assembly of  claim 12 , further including a second magnetic ring which couples the second rigid ring to the cutting cone, wherein the flexible ring allows the second magnetic ring to move relative to the first rigid ring. 
   
   
       15 . The assembly of  claim 14 , wherein the flexible ring allows the second magnetic ring to move towards and away from the first rigid ring. 
   
   
       16 . A method of providing a seal for an earth bit, comprising:
 providing a flexible ring;   coupling first and second rigid rings together using the flexible ring, wherein the flexible ring allows the first and second rigid rings to move relative to each other; and   positioning the flexible ring and the first and second rigid rings to provide a seal between a lug and a cutting cone.   
   
   
       17 . The method of  claim 16 , further including forming a dynamic seal between the first rigid ring and the lug and a static seal between the flexible ring and cutting cone. 
   
   
       18 . The method of  claim 16 , further including forming dynamic seals between the first and second rigid rings and the lug and cutting cone, respectively. 
   
   
       19 . The method of  claim 16 , further including positioning the flexible ring so it does not engage the lug or cutting cone. 
   
   
       20 . The method of  claim 16 , further including moving the first and second rigid rings towards and away from each other by compressing and stretching, respectively, the flexible ring. 
   
   
       21 . The method of  claim 16 , further including coupling a magnetic ring to the first rigid ring, wherein the magnetic ring couples the first rigid ring to the lug. 
   
   
       22 . The method of  claim 16 , further including coupling a magnetic ring to the second rigid ring, wherein the magnetic ring couples the second rigid ring to the cutting cone.