Seal assembly for a rotary earth bit

Abstract

An earth bit includes a cutting cone rotatably mounted to a lug, and a seal assembly positioned to provide a seal between the cutting cone and lug. The seal assembly includes first and second rigid rings, and a first elastomeric sealing ring which carries the first rigid ring. The second rigid ring rotates in response to the rotation of the first elastomeric sealing ring, so that the second rigid ring is less likely to lock.

1 . A seal assembly, comprising:
 a first rigid ring; and   a first elastomeric sealing ring which includes an arm coupled with the first rigid ring, the elastomeric sealing ring being repeatably moveable between flexed and unflexed conditions, wherein the first rigid ring moves in response to the first elastomeric sealing ring moving between the flexed and unflexed conditions.   
   
   
       2 . The assembly of  claim 1 , further including a second rigid ring carried by the first elastomeric sealing ring. 
   
   
       3 . The assembly of  claim 1 , wherein the first rigid ring includes an outwardly facing groove which receives the arm, the arm restricting the rotation of the first rigid ring relative to the first elastomeric sealing ring. 
   
   
       4 . The assembly of  claim 3 , wherein the first elastomeric sealing ring includes a protrusion carried by the arm, the protrusion restricting the rotation of the first rigid ring relative to the first elastomeric sealing ring. 
   
   
       5 . The assembly of  claim 4 , wherein the protrusion extends beyond a surface of the first rigid ring, the surface being opposed to a dynamic sealing surface of the first rigid ring. 
   
   
       6 . The assembly of  claim 4 , wherein the protrusion terminates flush with a surface of the first rigid ring, the surface being opposed to a dynamic sealing surface of the first rigid ring. 
   
   
       7 . The assembly of  claim 1 , further including a second elastomeric sealing ring carried by the first rigid ring, the second elastomeric sealing ring extending beyond a surface opposed to a dynamic sealing surface of the first rigid ring. 
   
   
       8 . An earth bit, comprising:
 a lug and cutting cone; and   a seal assembly which includes first and second rigid rings, and a first elastomeric sealing ring which carries the first rigid ring, wherein the second rigid ring rotates in response to the rotation of the first elastomeric sealing ring.   
   
   
       9 . The earth bit of  claim 8 , wherein the first elastomeric sealing ring forms a static sealing surface with the cutting cone, and the second rigid ring forms a dynamic sealing surface with the lug. 
   
   
       10 . The earth bit of  claim 8 , wherein the first elastomeric sealing ring forms a static sealing surface with the lug, and the second rigid ring forms a dynamic sealing surface with the cutting cone. 
   
   
       11 . The assembly of  claim 8 , wherein the first elastomeric sealing ring includes an arm which extends towards the second rigid ring. 
   
   
       12 . The assembly of  claim 11 , wherein the second rigid ring includes an outwardly facing groove which receives the arm. 
   
   
       13 . The assembly of  claim 11 , wherein the first elastomeric sealing ring includes a protrusion carried by the arm, wherein the protrusion engages the second rigid ring. 
   
   
       14 . The assembly of  claim 13 , wherein the protrusion extends beyond a surface opposed to a dynamic sealing surface of the second rigid ring. 
   
   
       15 . The assembly of  claim 13 , wherein the protrusion terminates proximate with a surface opposed to a dynamic sealing surface of the second rigid ring. 
   
   
       16 . The assembly of  claim 8 , further including a second elastomeric sealing ring carried by the second rigid ring, the second elastomeric sealing ring extending beyond a surface opposed to a dynamic sealing surface of the second rigid ring. 
   
   
       17 . A method of providing a seal for an earth bit, comprising:
 coupling a first elastomeric sealing ring and first rigid ring together;   coupling a second rigid ring to the first elastomeric sealing ring to form a seal assembly, wherein the first elastomeric sealing ring restricts the rotation of the second rigid ring relative to the first rigid ring; and   positioning the seal assembly to form a seal between a cutting cone and lug.   
   
   
       18 . The method of  claim 17 , wherein the step of coupling the second rigid ring and first elastomeric sealing ring together includes extending a protrusion through a notch. 
   
   
       19 . The assembly of  claim 18 , wherein the protrusion extends beyond a surface of the second rigid ring, the surface being opposed to a dynamic sealing surface of the second rigid ring. 
   
   
       20 . The assembly of  claim 18 , wherein the protrusion terminates proximate with a surface of the second rigid ring, the surface being opposed to a dynamic sealing surface of the second rigid ring. 
   
   
       21 . The method of  claim 17 , wherein the step of coupling the second rigid ring and first elastomeric sealing ring together includes extending an arm through an outwardly facing groove. 
   
   
       22 . The method of  claim 21 , further including positioning a second elastomeric sealing ring so it is carried by the second rigid ring, the second elastomeric sealing ring extending beyond a surface opposed to a dynamic sealing surface of the second rigid ring.