Earth bit having a screen

Abstract

An earth bit includes an earth bit body having a bore with a bearing passageway in fluid communication therewith. A screen extends through the bore and is repeatably moveable between rolled and unrolled conditions. The screen is in the rolled condition when extending through the bore. The screen screens a material flowing between the bore and bearing passageway.

1 . An earth bit, comprising:
 an earth bit body having a bore with a bearing passageway in fluid communication therewith; and   a screen extending through the bore, the screen being repeatably moveable between rolled and unrolled conditions.   
   
   
       2 . The earth bit of  claim 1 , wherein the screen is in the rolled condition when extending through the bore. 
   
   
       3 . The earth bit of  claim 1 , wherein the screen is biased against the earth bit body when extending through the bore. 
   
   
       4 . The earth bit of  claim 1 , wherein the screen covers the bearing passageway when extending through the bore. 
   
   
       5 . The earth bit of  claim 1 , wherein the screen screens a material flowing between the bore and bearing passageway. 
   
   
       6 . The earth bit of  claim 1 , wherein opposed ends of the screen are proximate to each other when the screen is in the rolled condition. 
   
   
       7 . The earth bit of  claim 1 , further including a shroud carried by the screen, the shroud being positioned proximate to the bearing passageway. 
   
   
       8 . An earth bit, comprising:
 an earth bit body having a bore with nozzle and bearing passageways in fluid communication therewith; and   a screen which extends through the bore and between the nozzle and bearing passageways.   
   
   
       9 . The earth bit of  claim 8 , wherein the screen is repeatably moveable between rolled and unrolled conditions. 
   
   
       10 . The earth bit of  claim 8 , wherein the screen is in the rolled condition when extending between the nozzle and bearing passageways. 
   
   
       11 . The earth bit of  claim 10 , wherein the screen is biased against the earth bit body when extending between the nozzle and bearing passageways. 
   
   
       12 . The earth bit of  claim 8 , wherein the screen screens a material flowing between the bore and the nozzle and bearing passageways. 
   
   
       13 . The earth bit of  claim 8 , further including a shroud positioned to divert a material flow between the bore and bearing passageway. 
   
   
       14 . The earth bit of  claim 13 , wherein the shroud is carried by the screen. 
   
   
       15 . An earth bit, comprising:
 an earth bit body having a bore with a bearing passageway in fluid communication therewith;   a screen which extends through the bore and screens a material flowing between the bore and bearing passageway; and   a shroud positioned to restrict the flow of the material between the bore and bearing passageway.   
   
   
       16 . The earth bit of  claim 15 , wherein the shroud includes a shroud opening that faces downstream from the material flow. 
   
   
       17 . The earth bit of  claim 16 , wherein the screen screens the material flowing through the shroud. 
   
   
       18 . The earth bit of  claim 15 , wherein the screen covers an opening of the bearing passageway that faces the bore. 
   
   
       19 . The earth bit of  claim 15 , wherein the screen is repeatably moveable between rolled and unrolled conditions. 
   
   
       20 . The earth bit of  claim 15 , wherein the screen is biased against the earth bit body.