Bit assembly for down-hole drills

Abstract

A bit assembly is for a drill having a casing, a central axis and a hammer movably disposed within the casing. The bit assembly includes a chuck with a tubular body having first and second ends, the first end being connected with the casing such that the second end is spaced axially therefrom, and one or more openings extending generally axially from the second end toward the first end. A bit includes a body with a tubular portion having a cavity and one or more axial lugs, the lug(s) being disposable within the chuck opening(s). A retainer is coupled with the chuck, disposable within the bit cavity and engageable with the bit lug(s) so as to releasably couple the bit with the chuck. The retainer is preferably a deflectable ring sized to receive a portion of the hammer, such that the hammer prevents disengagement of the retainer from the bit.

1 . A bit assembly for a drill, the drill including a casing and a hammer movably disposed within the casing and having an end, the bit assembly comprising:
 a bit having a cavity; and   a retainer connected with the casing, disposable within the bit cavity, and releasably engageable with bit so as to couple the bit with the casing.   
   
   
       2 . The bit assembly as recited in  claim 1  wherein the retainer includes a generally annular body having a central opening configured to receive the hammer end such that the hammer prevents disengagement of the retainer from the bit when the hammer end is disposed within the retainer opening. 
   
   
       3 . The bit assembly as recited in  claim 2  wherein the retainer is configured to be at least partially radially displaceable between an outer radial position at which at least a portion of the retainer is engaged with the bit so as to connect the bit with the casing, and an inner radial position at which the retainer is generally disengaged from the bit such that the bit is disconnectable from the casing, the hammer preventing displacement of the retainer to the inner position when the hammer end is disposed within the retainer opening. 
   
   
       4 . The bit assembly as recited in  claim 3  wherein the bit includes a body with a cylindrical portion with opposing first and second axial ends and a generally tubular portion extending axially from the first end, the tubular portion at least partially bounding the bit cavity, the cylindrical body first end having a cutting surface and the body second end having an impact surface bounding an axial end of the cavity and strikeable by the hammer end to drive the cutting surface into engagement with a work surface. 
   
   
       5 . The bit assembly as recited in  claim 4  wherein the bit body cylindrical portion has a hole extending between the first and second axial ends and being sized to receive a pusher tool for displacing the hammer end from the bit cavity. 
   
   
       6 . The bit assembly as recited in  claim 1  further comprising a chuck connected with the casing, the retainer being coupled with one of the chuck and the bit and configured to movably connect the bit with the chuck. 
   
   
       7 . The bit assembly as recited in  claim 6  wherein the chuck has a cavity and the retainer is simultaneously disposable within the chuck cavity and the bit cavity. 
   
   
       8 . The bit assembly as recited in  claim 6  wherein:
 the chuck includes a generally tubular body with first and second ends and a central axis extending between the two ends, the first end being connected with the casing and the second end being spaced axially from the casing, the body having at least one opening extending generally axially from the second end toward the first end;   the bit includes a body with a central axis, a cylindrical portion, and a generally tubular portion spaced axially from the cylindrical portion, the tubular portion providing the bit cavity and at least one axial lug, the lug being at least partially disposable within the chuck opening; and   the retainer is disposable within the bit cavity and engageable with the at least one bit lug so as to releasably couple the bit with the chuck.   
   
   
       9 . The bit assembly as recited in  claim 8  wherein:
 the chuck body includes a plurality of generally axially extending lugs and a plurality of the openings, each opening being defined between a separate adjacent pair of the chuck axial lugs; and   the bit body includes a plurality of the axial lugs and a plurality of generally axially-extending openings, each opening being defined between a separate adjacent pair of the bit axial lugs, each bit axial lug being disposable within a separate one of the chuck openings and each bit axial opening being configured to receive a separate one of the chuck lugs such that when bit is coupled with the chuck, the bit lugs move axially within the chuck openings and the chuck lugs move axially within the bit openings.   
   
   
       10 . The bit assembly as recited in  claim 9  wherein:
 each one of the chuck lugs includes a generally cantilever-like body having a first end connected with a remainder of the chuck body and a second, free end spaced axially from the chuck body remainder; and   each one of the bit lugs includes a generally cantilever-like body having a first end connected with a remainder of the bit body and a second, free end spaced axially from the bit body remainder.   
   
   
       11 . The bit assembly as recited in  claim 9  wherein each one of the chuck lugs and the bit lugs has two opposing radial contact surfaces and inner and outer circumferential surfaces, the inner surfaces of the bit lugs collectively defining at least a portion of the bit cavity, each bit lug contact surface being generally slidable against a separate one of the chuck lug contact surfaces. 
   
   
       12 . The bit assembly as recited in  claim 9  wherein each chuck lug has an inner circumferential surface and a generally circumferential groove extending outwardly from the inner surface, the retainer being disposed within all of the chuck lug grooves so as connect the retainer with the chuck. 
   
   
       13 . The bit assembly as recited in  claim 9  wherein each bit lug has an inner circumferential surface and a generally arcuate shoulder extending generally radially inwardly from the inner surface, each shoulder being engageable with the retainer to movably couple the bit with the chuck. 
   
   
       14 . The bit assembly as recited in  claim 13  wherein:
 the retainer has a radial catch surface facing generally toward the chuck upper end;   each bit lug shoulder has a stop surface facing generally toward the chuck lower end and disposable upon the retainer catch surface so as to prevent axial displacement of the bit.   
   
   
       15 . The bit assembly as recited in  claim 13  wherein
 the retainer body is at least partially moveable between inner and outer radial positions; and   each lug shoulder has a generally angled release surface such that when the hammer end is located externally of the retainer opening and a force of at least a predetermined magnitude is applied to the bit generally in a direction away from the chuck, the shoulder angled surfaces slide against the retainer body so as displace the retainer body toward the inner radial position such that the bit disengages the from the retainer.   
   
   
       16 . A bit assembly for a drill, the drill having a casing and an axis extending centrally through the casing, the bit assembly comprising:
 a chuck including a generally tubular body with first and second ends, the first end being connected with the casing such that the second end is spaced axially from the casing, and at least one opening extending generally axially from the second end toward the first end;   a bit including a body with a tubular portion, the tubular portion having a cavity and at least one axial lug, the lug being at least partially disposable within the chuck opening; and   a retainer coupled with the chuck, disposable within the bit cavity and engageable with the at least one bit lug so as to releasably couple the bit with the chuck.   
   
   
       17 . The bit assembly as recited in  claim 16  wherein the chuck has a cavity and the retainer is simultaneously disposable within the chuck cavity and the bit cavity. 
   
   
       18 . The bit assembly as recited in  claim 16  wherein:
 the chuck body includes a central axis, the central axis being coaxial with the casing axis when the chuck is connected with the casing, a plurality of generally axially extending lugs and a plurality of the openings, each opening being defined between a separate adjacent pair of the chuck axial lugs; and   the bit body includes a central axis, the central axis being coaxial with the bit axis when the bit is coupled with the chuck, a plurality of the axial lugs and a plurality of generally axially-extending openings, each opening being defined between a separate adjacent pair of the bit axial lugs, each bit axial lug being disposable within a separate one of the chuck openings and each bit axial opening being configured to receive a separate one of the chuck lugs such that when bit is coupled with the chuck, the bit lugs move axially within the chuck openings and the chuck lugs move axially within the bit openings.   
   
   
       19 . The bit assembly as recited in  claim 18  wherein:
 each one of the chuck lugs includes a generally cantilever member having a first end connected with a remainder of the chuck body and a second, free end spaced axially from the chuck body remainder; and   each one of the bit lugs includes a generally cantilever member having a first end connected with a remainder of the bit body and a second, free end spaced axially from the bit body remainder.   
   
   
       20 . The bit assembly as recited in  claim 18  wherein each chuck lug has an inner circumferential surface and a generally circumferential groove extending outwardly from the inner surface, the retainer being disposed within all of the chuck lug grooves so as connect the retainer with the chuck. 
   
   
       21 . The bit assembly as recited in  claim 16  wherein the retainer includes a generally annular body having a central opening configured to receive the hammer end such that hammer prevents disengagement of the retainer from the bit when the hammer end is disposed within the retainer opening. 
   
   
       22 . The bit assembly as recited in  claim 21  wherein the retainer is configured to be at least partially radially displaceable between an outer radial position at which at least a portion of the retainer is engaged with the bit so as to connect the bit with the casing, and an inner radial position at which the retainer is generally disengaged from the bit such that the bit is disconnectable from the casing, the hammer preventing displacement of the retainer to the inner position when the hammer end is disposed within the retainer opening. 
   
   
       23 . A bit assembly for a drill, the drill having a casing, the bit assembly comprising:
 a chuck including a generally tubular body with a first end connected with the casing, an opposing second end, a central axis extending between the two ends, inner and outer circumferential surfaces, and at least two through holes each extending generally axially from the second end toward the first end and generally radially between the inner and outer surfaces; and   a bit including a body with a central axis, the body having a generally cylindrical portion with a cutting surface and at least two cantilever-like lugs extending generally axially from the base portion and spaced circumferentially about the axis, each lug being disposable within a separate one of the chuck through holes, the bit being movably coupled with the chuck such that the lugs displace generally axially within the chuck holes as the bit moves axially with respect to the chuck.   
   
   
       24 . The bit assembly as recited in  claim 23  wherein:
 the chuck body includes a generally circular sidewall portion, a plurality of generally cantilever-like lugs extending axially from the sidewall portion, and a plurality of the openings, each opening being defined between a separate adjacent pair of the chuck lugs; and   the bit body includes a plurality of the bit lugs and a plurality of generally axially-extending openings, each opening being defined between a separate adjacent pair of the bit lugs, each bit axial lug being disposable within a separate one of the chuck openings and each bit axial opening being configured to receive a separate one of the chuck lugs such that when bit is coupled with the chuck, the bit lugs move axially within the chuck openings and the chuck lugs move axially within the bit openings.   
   
   
       25 . The bit assembly as recited in  claim 23  further comprising a retainer configured to connect the bit with the chuck. 
   
   
       26 . The bit assembly as recited in  claim 25  wherein:
 the bit body has a cavity defined generally between the bit lugs; and   the retainer is disposable within the bit cavity and releasably engageable with the bit lugs to removably connect the bit with the chuck.   
   
   
       27 . The bit assembly as recited in  claim 25  wherein:
 the drill further includes a hammer movably disposed with the casing and having an end contactable with the bit so as to force the bit cutting surface into engagement with a work surface; and   the retainer is at least partially radially inwardly displaceable so as to disengage from the bit and further has an opening configured to receive a portion of the hammer end such that the hammer prevents radial displacement of the retainer so as to retain the bit coupled with the chuck.   
   
   
       28 . The bit assembly as recited in  claim 23  wherein:
 the drill further includes a hammer movably disposed with the casing and having an end contactable with the bit so as to force the bit cutting surface into engagement with a work surface; and   the bit body further has a cavity defined generally between the lugs and the bit base portion has a contact surface partially bounding the bit cavity, the hammer end being disposable within the bit cavity and strikingly contactable with the bit contact surface.   
   
   
       29 . A bit assembly for a drill, the drill having a casing, the bit assembly comprising:
 a chuck connected with the casing and having a generally tubular body, the tubular body having first and second ends, a central axis extending between the two ends, and at least one of an opening extending generally axially from the second end toward the first end and a generally axial lug; and   a bit having body with a generally tubular portion, the tubular body portion having a first end connected with a remainder of the body and a second end, a cavity extending inwardly from the second end, and at least one of an opening extending generally axially from the second end generally toward the first end and configured to receive at least a portion of a chuck lug and a generally axial lug disposable within a chuck opening; and   a retainer coupled with the chuck, disposable within the bit cavity and engageable with the bit tubular portion so as to releasably connect the bit with the chuck.