Continuous Sampling Drill Bit

Abstract

A drill bit having a central axis can comprise a shank defining an inner bore and a crown having a cutting face. The crown can define an outer operative circumference. The crown can comprise a core-receiving slot in communication with the inner bore of the shank. One or more peripheral slots can be in communication with the inner bore of the shank. The crown can comprise one or more face channels that are in communication with the core-receiving slot and a respective peripheral slot. A base portion can be positioned within the core-receiving slot. The base portion can define a breaking surface. The peripheral slots can be configured to receive fluid moving in a distal direction toward the cutting face of the crown. The face channels can be configured to deliver fluid from the respective peripheral slot to the core-receiving slot.

What is claimed is: 
     
         1 . A drill bit having a central axis, the drill bit comprising:
 a shank defining an inner bore; and   a crown having a cutting face, wherein the crown defines an outer operative circumference and comprises:
 a core-receiving slot in communication with the inner bore of the shank; 
 at least one peripheral slot in communication with the inner bore of the shank, the at least one peripheral slot being positioned radially between the core-receiving slot and the outer operative circumference of the crown; 
 at least one face channel, wherein each face channel of the at least one face channel extends between and is in (fluid) communication with the core-receiving slot and a respective peripheral slot of the at least one peripheral slot; and 
 a base portion positioned within the core-receiving slot, wherein the base portion defines a breaking surface, wherein at least a portion of the breaking surface, or a plane tangential thereto, is oriented at an oblique angle to the central axis, 
   wherein the at least one peripheral slot is configured to receive fluid moving in a distal direction toward the cutting face of the crown, and wherein the at least one face channel is configured to deliver fluid from the at least one peripheral slot to the core-receiving slot.   
     
     
         2 . The drill bit of  claim 1 , wherein the at least one peripheral slot comprises a plurality of peripheral slots, and wherein at least one peripheral slot of the plurality of peripheral slots is not in communication with a face channel of the at least one face channel. 
     
     
         3 . The drill bit of  claim 1 , wherein the at least one peripheral slot comprises a plurality of peripheral slots, and wherein the at least one face channel comprises at least two face channels. 
     
     
         4 . The drill bit of  claim 2 , wherein at least one peripheral slot of the plurality of peripheral slots has a different arc length than at least one other peripheral slot of the plurality of peripheral slots. 
     
     
         5 . The drill bit of  claim 2 , wherein the plurality of peripheral slots comprises a pair of opposing peripheral slots spaced apart along a transverse axis that is perpendicular to the central axis. 
     
     
         6 . The drill bit of  claim 5 , wherein a first peripheral slot of the pair of opposing peripheral slots has a different arc length than a second peripheral slot of the pair of opposing peripheral slots. 
     
     
         7 . The drill bit of  claim 2 , wherein the plurality of peripheral slots comprises first and second pairs of opposing peripheral slots, wherein the first pair of opposing peripheral slots are spaced apart along a first transverse axis that is perpendicular to the central axis, and wherein the second pair of opposing peripheral slots are spaced apart along a second transverse axis that is perpendicular to the central axis. 
     
     
         8 . The drill bit of  claim 7 , wherein the first and second transverse axes intersect the central axis, and wherein the first and second transverse axes are perpendicular or substantially perpendicular to one another. 
     
     
         9 . The drill bit of  claim 1 , wherein the crown comprises:
 a wall that defines the outer operative circumference of the crown; and   a plurality of inner crown portions that define the core-receiving slot.   
     
     
         10 . The drill bit of  claim 9 , wherein each peripheral slot of the at least one peripheral slot is at least partially defined by:
 a respective outer wall portion of the wall of the crown; and   a respective inner crown portion of the plurality of inner crown portions.   
     
     
         11 . The drill bit of  claim 10 , wherein each face channel of the at least one face channel is defined by a respective inner crown portion of the plurality of inner crown portions. 
     
     
         12 . The drill bit of  claim 10 , wherein the at least one peripheral slot comprises a plurality of peripheral slots, wherein the inner crown portion that at least partially defines a first peripheral slot of the plurality of peripheral slots has a radial thickness that is different than a radial thickness of the inner crown portion that at least partially defines a second peripheral slot of the plurality of peripheral slots. 
     
     
         13 . The drill bit of  claim 9 , wherein the base portion extends between opposing first and second inner crown portions of the at least one inner crown portion, wherein the first and second inner crown portions are spaced apart along a first transverse axis that intersects the central axis of the drill bit and is perpendicular or substantially perpendicular to the central axis. 
     
     
         14 . The drill bit of  claim 13 , wherein each of the first and second inner crown portions comprises:
 a first axial edge;   a second axial edge;   a medial axial edge;   a first inner surface extending between the first axial edge and the medial axial edge; and   a second inner surface extending between the medial axial edge and the second axial edge.   
     
     
         15 . The drill bit of  claim 14 , wherein the first inner surface of each of the first and second inner crown portions is planar or substantially planar. 
     
     
         16 . The drill bit of  claim 14 , wherein the second inner surface of each of the first and second inner crown portions has a convex curvature. 
     
     
         17 . The drill bit of  claim 1 , wherein the wall defines at least one axial channel that is radially inwardly recessed from the outer operative circumference of the crown. 
     
     
         18 . A drilling assembly comprising:
 an outer tube;   an inner tube received within the outer tube, the inner tube and the outer tube cooperating to define an annular space; and   a drill bit as in  claim 1 , wherein the shank of the drill bit is threadedly coupled to the outer tube.   
     
     
         19 . The drilling assembly of  claim 18 , further comprising a drill sub having a proximal end and an opposed distal end, wherein the drill sub defines a central bore that extends between, and provides fluid communication between, the core receiving slot of the crown of the drill bit and the inner tube. 
     
     
         20 . A drill bit having a central axis, the drill bit comprising:
 a shank defining an inner bore;   a crown having a cutting face, wherein the crown has an outer circumferential surface, wherein the crown comprises:
 a core-receiving slot in communication with the inner bore of the shank; 
 at least one face channel, wherein each face channel of the at least one face channel extends between and is in communication with the core-receiving slot and the outer operative circumference of the crown; and 
 a base portion positioned within the core-receiving slot, wherein the base portion defines a breaking surface, wherein at least a portion of the breaking surface, or a plane tangential thereto, is oriented at an oblique angle to the central axis, 
   wherein the at least one face channel is configured to receive fluid flowing distally along the outer surface of the crown and deliver fluid from the outer surface of the crown to the core-receiving slot.