CA1236083A - Hammer drill bit and sub-assembly - Google Patents
Hammer drill bit and sub-assemblyInfo
- Publication number
- CA1236083A CA1236083A CA000477688A CA477688A CA1236083A CA 1236083 A CA1236083 A CA 1236083A CA 000477688 A CA000477688 A CA 000477688A CA 477688 A CA477688 A CA 477688A CA 1236083 A CA1236083 A CA 1236083A
- Authority
- CA
- Canada
- Prior art keywords
- lowermost
- cutting
- extending
- drill bit
- central opening
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
ABSTRACT OF THE DISCLOSURE
A cylindrical hammer drill bit with a central fluid passage and having a first group of circumferentially spaced lowermost cutting surfaces located on lowermost arcuate segments spaced by elongated upwardly extending circumferen-tially spaced slots and a second group of circumferentially spaced uppermost cutting surfaces located on intermediate arcuate segments at the upper end of the slots. Each of the cutting surfaces has an arcuate segment portion on the outer periphery of the drill bit formed at the intersection of upwardly inwardly sloping surfaces with the periphery of the drill bit; and radially inwardly upwardly inclined radial segment portions located on radially rib portions on the upwardly inwardly sloping surfaces. Each radial rib portion is connected to an elongated inwardly facing fluid slot.
A cylindrical hammer drill bit with a central fluid passage and having a first group of circumferentially spaced lowermost cutting surfaces located on lowermost arcuate segments spaced by elongated upwardly extending circumferen-tially spaced slots and a second group of circumferentially spaced uppermost cutting surfaces located on intermediate arcuate segments at the upper end of the slots. Each of the cutting surfaces has an arcuate segment portion on the outer periphery of the drill bit formed at the intersection of upwardly inwardly sloping surfaces with the periphery of the drill bit; and radially inwardly upwardly inclined radial segment portions located on radially rib portions on the upwardly inwardly sloping surfaces. Each radial rib portion is connected to an elongated inwardly facing fluid slot.
Description
~236083 llAM~IFR DRILL BIT AND SUB-ASSEMBLY
Back~round of Invention This invention relates to a drill bit and sub-assembly for use with a rcverse circulation hammer type drill pipe.
Conventional reverse circu]ation hammer drill bits have o5 genera]]y been un~ble to provide a high consistency o~
recnvery of corc salllplcs througllout tlle deptl~ of thc drilling operation. Lack of consi~tent air flow and pres-sure through tlle central return has caused inconsistent recovery of samples which has resulted, in many cases, in incorrect and mir]eading mineral content assays of the ~ample. Additionally, thc design of conventional hammer drill bits has resulted, not only in lack of consistency of recovery of core samples, but also in inefficiency in drilling.
The primary object of the present invention i5 to imyrove consistoncy of recovery of core samples and offi-ciency of drilling. The primary object is achieved by improvemerlts in the construction an-l design of the drill bit and sub-as~embly whicll improve cuttinq and removal of Cllips and mainte--ancc of air pressurc in the inner pipe.
Brief DescriPtion of Drawinq Fig. 1 is an exE~loùed isomotric sectional view of thc drlll hit and sub-a9sembly of the present invcntion;
Fig. 2 is a sectional view of the drill bit of the present lnvclltion;
12;~6083 Fig. 3 is an enlarged cross-sectional view of the drill bit.
Eig. 4 is an end view of the drill bit of Fig. 3;
Fig. 5 is a cross-section of a drill bit and sub-05 assembly of the preserlt invontion; and E ig. 6 is an alternative embodiment illustrating carbide inserts used in conjunction with the hamrner drill bit of the present invention.
lo Detailed DescriPtion As shown in Fig. 1, the drill bit assembly comprises a drill bit 20, known as a Selcon bit, which is connected to the downhole end Or ~n bit suh- conncctor means 22 which is, in turn, connected to the downhole end of the outer pipe 28 of a section of dual wall drill string 26. The inner pipe 30 of drill string 26 is coupled to bit sleeve 24 by a connector sleeve moans 32 which fits over O-rings 34, 36 which are mountod in grooves 38, 40, respectively on bit sleeve 24.
In operation, one or more sections of drill string 26 are raised and lowcred by a converltional hammer drlll type rlg to reclprocably drive the drill bit 20 into the oarth to cut a drill hole. Compressed air or other fluid under pressure is forced down the outer passage 42 of the dual wall drill string sections, as indicated by arrows 44, 46, and into a central cavity 4a in the drill bit 20, which is connected to center passage 50 of bit 91eeve 24 through a center pas~qage in inner pipe 30. Thus, loose bits and piece~ -f ourtrlen matorlals are carried upwardly to the L~. ........ .... . .... ... . ... .... ... . .... ..... .. .. .. . .
, ~, .~
, . .
surface by air prcssure where th~y can be analy~ed and evaluated.
The drill bit 20 comprises a on~- piece member made from a casting of metallic material such as 4100 to 4300 05 series steel. si~ slceve 24 and bit sub 22 are machined from 4140 or 4300 series steel tubing. Drill bit 20 and bit sub 22 are case hardened by electrical induction or sand base hardening to a hardnes5 of between 35 and 50 on the Rockwell scale. The upper cnd of drill bit 20 is provided with a large diallleter bore havillg thread9 52 for connection to the lower threaded end portion 54 of the bit sub 22. Tlle lower end portion of drill bit 20 is provided with a reduced diameter bore which provides all annular seat 76 abutting against lower surface 74 of bit sleeve 24. Annular seal and shock ring 62 is disposed on annular flange 64 to provide an air tight seal between the bottom surface 65 of annular ring 68 and the inner wall of bit sub 22 to ensure passage of air as indicated by arrows 44, 46 and to absorb shock from bit sleeve 24.
~ottom surful,e portion 74 of bit sleeve 24 abut6 against surface 76 such that air passing between the outer wall surface 78 at bit sleeve 24 and annular ring 68 flow through notched air passage mean~ ~0, a2 which extend through shortened and elongated cutting teeth 84, 86, respectively. Threaded portion 70 of bit sub 22 engages threaded portion 72 of drill string 26 for assembly of the drill bit asst!mb]y illustrated in ~'ig. 1.
FLg. 2 illugtrates a plurality of circumferentially and alternately syaced shortened cutting mean~ 90 and elongated cuttin9 moans 92 011 the ower ond portion of the drill bi,t, ., , - - -,,--, .~:
. ~
: ' . -,::
:
~, ' , `,~' ` :
~, ~23601~3 Each shortenecl and elongated cutti.ng means have shortened and elongated cutting teeth 84, 86, respectively, with notched air passage means formed therein for enabling compressed air to flow into central cavity 48, as ~et forth 05 above.
Eigs. 3 alld 4 illustrate axially extended cutting means 92 which comprises an arcuate segmental peripheral cutting eflge 9ri formed by the intersection of annular drill bit outer surface 96 and beveled surfaces 98, 100 located on opposite sides of a radially inwardly extending rib portion forming elongated cutting tooth 86 having an upwardly and inwardly sloping cutting edge 102. Each cutting tooth 86 h~s flat circumferentially spaced axially extending side surface~, 104, ]06 connected by curved end surfaces 108, llO
which intersect to form cutting edge 102. Each cutting tooth B6 also has arcuate segmental inner surfaces 112. Air passa~c moans 82 are ccrltrally located in cutting tooth 86 and open through surfacee 112. Each axially extended cutting means is furthor defined by axially extending side wall portions 116, 118 which deLine lateral circum-ferentinlly spaced gaps 120 therebetween, Surfaces 116, 118 COnlprl~le A flelt yarallel outermost portlon 122 and a concavc innermost portion 124.
Each axially shortened cutting means 90 comprises an arcuate segmental pcripheral cutting edge portion 126 formed by the intersection of annular outer drill bit surface 9G
and slightly bovcl.cd surfaccs 128, 130 located on opposite sides of a radially inwardly extending cutting tooth 132 having a laterally inwardly .sloping cuttil-g edgc 134 on thc 30 lowor cnd thereof. I:elch cutting tooth 132 has flat ,, ;'', .
'.' ' ~ ' ~236083 circulllferenti.llly spacod axially extending side surfaces 136 " 38 connected by curvcd end surfaces 140 142 which intersect to form cutting edge 134. Each rib portion also has arcuate segment and inner surfaces 144 defining cir-05 cumferentially spaced portions of boro 48. Air passage means 80 are centrally located in cutt;ng tooth 132 and open through surfaces 144.
Each oF the cutting teeth 86 132 extend downwardly in the drilling position from a common plane 146 spaced down-wardly from snrface 148 a relativoly ~hort axial distance.
Each of the air passages 80, 82 begin at annular lateral surface 150 which defines the end of threaded portion 52.
~ir passages 82 extend axially downwardly beyond cutting surfaces 126 with a lowermost portion 152 located radially opposite gaps 120 below lateral surfaces 128 130. Thus gaps 120 provide the additional function of air flow between adjacent onos of the axially extended cutting means. The oppositely curvod side walls 124 form pockets to facilitate collection of cuttings and facilitate flow of cuttings into central cavi~y 48 and upwardly into connector tube passage 50 .
In thc preserltly proferred crnbodiment, the angles of the beveled r;urfaces 98, 100, 128, 130 are approximately 65 degrees from the vertical axis of tho drill bit. The angle of cutting edges 102, 134 15 approximately a3 degrees from the vertical axis of the drill bit.
Fig. 5 i9 a cutaway assombly drawing of the drill bit asnembly o tho presont invention in an assembled configura-tion. Drill string 26 is attachod to bit sub 22 by way of threaded portions 72 of drill sfrirlg 2fi and threaded ..... . _ _ _ . .. , . _ .. _ _ . _ .. _ .--.--.. --.. ---- . - - -12360B~
.
portions 70 of bit sub 22. In a similar manner bit sub 22 is coupled to drill bit 20 by way of male threaded portions 54 of bit suh 22 and femalc threaded portions 52 of drill bit 20. 13i~ sleeve 24 is disposed in the central opening 05 formed by the assembly of drill bit 20 bit sub 22 and drill string 26. sit sleeve 24 is dispc sed between flange portion 32 of innrr piiJC 30 and ~nnulnr sen1 62 disposed in bit ~.ub 22. Bit ;1 ceve 24 forms an annular cylindrical cavity having a center passage 50 for movement of air and collected lO bit samples in an upward direction. ~3it sleeve 24 separates center passage SU from external air passage 42. O-rir,gs 34, 36 provide ar1 airtight geal between outer passage 42 and center passage 50. Air is pumped down the outer passageway 42 of the drill string from the surface and proceeds along 15 the outer passage as indicated by arrows 44, 46. Air passes between the inner surface of annular ring 68 and outer surface 78 of hit sleeve 24 into notched portions 80 82 of cutting tceth a4, a6. Annular ring 62 provides an airti~Jht seal betwcen annular ring 68 and the inn~r wall of bit sub 20 22 ar1û abrorbr shock transn1ittcd by bit sleeve 24.
The co11figuration of air passage means 80, a2 directs the airflow in an inward and upward direction to provide a more consistent air return. Both pressure and velocity of the air rcturn remain more constant during the drilling 25 process bccause of the inward and upward angle at which the air is directr1d throug11 air passages 80, 82. The air medium functions to blow the sample away from the cutting edges of the bit and direct the sample through opening 48 into the void ureu oF ccntrfl] passage 50 such that the sample is 30 directed alony the path of least resistance through ccntral _ _ _ _ _ _ , , _, _ _ _ _ _ _ _,, _,, , . , . , _ , .. . . . . .
1Z360~3 passage 50. In this manner, the consistency of the sample by volume is constant during thc entire drilling process so as to provide a sample of mineral content which remains constant with vertical drilling deptil. This is of high 05 i,nportance in exploratory drillinq especially of desert aluvi~ls and ~lacer exploration to accurately determine mincral content ol :anlplcs to a-cumulate data or the purpose of evaluating the feasibility of a mining operatlo~l.
Failure to c~ficiently and consistently return the sample to the surface nlay affect the accuracy of the perrentage pcr ton of rare metals of the sample retrieved during the drilling process.
Thr- ~Iresent invention also provides extra cutting edge.
The axially .shortened cutting means 90 provides room for lS expansion of samplcs which havr: bcen cut by axially extended cutting means 92 until the sample is removed through central opening 50. The cutting edges are beveled to increase the fecd a1lgle and to :.treamlinc the removal of sample from the cutting surfaces during the drilling process. The angle of the cutting edges provides for more cutting edge as the cutting procc:R pro~eeds into thc cut material. Moreover, the design of the present invention provides for additional cuttiny t-cth to Lurthl3r incroasc he efficir~ncy of the hammer drill hit of the present inven~ion Fig. 6 illustrate3 an alternative embodiment which utilizes carbide inserts 160, 162, 164, 168 adjacent cutting edges in drill bit 20. Each of the cnrbide inserts is inserted into a grrovo such as groove 170 adjacent the cutting erlge and sccured in p]nrc hy gluing or othrc~r suit-able means of attaching the carnide lnserts in the grooves.
.. _ . _ .. ., _ . . .. _ _, ., ., .. _ . .. _ . . .. _ .. _ _ _ _ . . _ _ _ .. _ . . . , .. , _ . _, . . . . .. _ .
:' , . .
~Z36083 .
The carbide inscrts fullction to increase the hardness of the cutting edges and consequently extend the effective use of the drill bit and premature wear of the cutting edges. The grooves in the cutting edges are machined in drill bit 2C
os prior to the hardening process. Once the grooves are machined in the drill bit 20, the surfaces are case hardened by el~ctrical induction, as de~crihed above.
The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, alld other modifications and variations may be pos~ibl~ in li~ht of the above teaching.s.
The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utili7e the invention in various embodiments and various modifications as are suited to the particular use contemplated. It i3 intended that the appended claims be construed to include other alternative embodiments of the invcnti.on except insoear as limited by the prior art.
. _, . ., _ _ .. _ . , . _ _ _ .. _ , .. _ _ _ . ., _ _ . ..... ... ,, . , . , . . . ... ... .. . . . . _ _ _ .
....... . ..
Back~round of Invention This invention relates to a drill bit and sub-assembly for use with a rcverse circulation hammer type drill pipe.
Conventional reverse circu]ation hammer drill bits have o5 genera]]y been un~ble to provide a high consistency o~
recnvery of corc salllplcs througllout tlle deptl~ of thc drilling operation. Lack of consi~tent air flow and pres-sure through tlle central return has caused inconsistent recovery of samples which has resulted, in many cases, in incorrect and mir]eading mineral content assays of the ~ample. Additionally, thc design of conventional hammer drill bits has resulted, not only in lack of consistency of recovery of core samples, but also in inefficiency in drilling.
The primary object of the present invention i5 to imyrove consistoncy of recovery of core samples and offi-ciency of drilling. The primary object is achieved by improvemerlts in the construction an-l design of the drill bit and sub-as~embly whicll improve cuttinq and removal of Cllips and mainte--ancc of air pressurc in the inner pipe.
Brief DescriPtion of Drawinq Fig. 1 is an exE~loùed isomotric sectional view of thc drlll hit and sub-a9sembly of the present invcntion;
Fig. 2 is a sectional view of the drill bit of the present lnvclltion;
12;~6083 Fig. 3 is an enlarged cross-sectional view of the drill bit.
Eig. 4 is an end view of the drill bit of Fig. 3;
Fig. 5 is a cross-section of a drill bit and sub-05 assembly of the preserlt invontion; and E ig. 6 is an alternative embodiment illustrating carbide inserts used in conjunction with the hamrner drill bit of the present invention.
lo Detailed DescriPtion As shown in Fig. 1, the drill bit assembly comprises a drill bit 20, known as a Selcon bit, which is connected to the downhole end Or ~n bit suh- conncctor means 22 which is, in turn, connected to the downhole end of the outer pipe 28 of a section of dual wall drill string 26. The inner pipe 30 of drill string 26 is coupled to bit sleeve 24 by a connector sleeve moans 32 which fits over O-rings 34, 36 which are mountod in grooves 38, 40, respectively on bit sleeve 24.
In operation, one or more sections of drill string 26 are raised and lowcred by a converltional hammer drlll type rlg to reclprocably drive the drill bit 20 into the oarth to cut a drill hole. Compressed air or other fluid under pressure is forced down the outer passage 42 of the dual wall drill string sections, as indicated by arrows 44, 46, and into a central cavity 4a in the drill bit 20, which is connected to center passage 50 of bit 91eeve 24 through a center pas~qage in inner pipe 30. Thus, loose bits and piece~ -f ourtrlen matorlals are carried upwardly to the L~. ........ .... . .... ... . ... .... ... . .... ..... .. .. .. . .
, ~, .~
, . .
surface by air prcssure where th~y can be analy~ed and evaluated.
The drill bit 20 comprises a on~- piece member made from a casting of metallic material such as 4100 to 4300 05 series steel. si~ slceve 24 and bit sub 22 are machined from 4140 or 4300 series steel tubing. Drill bit 20 and bit sub 22 are case hardened by electrical induction or sand base hardening to a hardnes5 of between 35 and 50 on the Rockwell scale. The upper cnd of drill bit 20 is provided with a large diallleter bore havillg thread9 52 for connection to the lower threaded end portion 54 of the bit sub 22. Tlle lower end portion of drill bit 20 is provided with a reduced diameter bore which provides all annular seat 76 abutting against lower surface 74 of bit sleeve 24. Annular seal and shock ring 62 is disposed on annular flange 64 to provide an air tight seal between the bottom surface 65 of annular ring 68 and the inner wall of bit sub 22 to ensure passage of air as indicated by arrows 44, 46 and to absorb shock from bit sleeve 24.
~ottom surful,e portion 74 of bit sleeve 24 abut6 against surface 76 such that air passing between the outer wall surface 78 at bit sleeve 24 and annular ring 68 flow through notched air passage mean~ ~0, a2 which extend through shortened and elongated cutting teeth 84, 86, respectively. Threaded portion 70 of bit sub 22 engages threaded portion 72 of drill string 26 for assembly of the drill bit asst!mb]y illustrated in ~'ig. 1.
FLg. 2 illugtrates a plurality of circumferentially and alternately syaced shortened cutting mean~ 90 and elongated cuttin9 moans 92 011 the ower ond portion of the drill bi,t, ., , - - -,,--, .~:
. ~
: ' . -,::
:
~, ' , `,~' ` :
~, ~23601~3 Each shortenecl and elongated cutti.ng means have shortened and elongated cutting teeth 84, 86, respectively, with notched air passage means formed therein for enabling compressed air to flow into central cavity 48, as ~et forth 05 above.
Eigs. 3 alld 4 illustrate axially extended cutting means 92 which comprises an arcuate segmental peripheral cutting eflge 9ri formed by the intersection of annular drill bit outer surface 96 and beveled surfaces 98, 100 located on opposite sides of a radially inwardly extending rib portion forming elongated cutting tooth 86 having an upwardly and inwardly sloping cutting edge 102. Each cutting tooth 86 h~s flat circumferentially spaced axially extending side surface~, 104, ]06 connected by curved end surfaces 108, llO
which intersect to form cutting edge 102. Each cutting tooth B6 also has arcuate segmental inner surfaces 112. Air passa~c moans 82 are ccrltrally located in cutting tooth 86 and open through surfacee 112. Each axially extended cutting means is furthor defined by axially extending side wall portions 116, 118 which deLine lateral circum-ferentinlly spaced gaps 120 therebetween, Surfaces 116, 118 COnlprl~le A flelt yarallel outermost portlon 122 and a concavc innermost portion 124.
Each axially shortened cutting means 90 comprises an arcuate segmental pcripheral cutting edge portion 126 formed by the intersection of annular outer drill bit surface 9G
and slightly bovcl.cd surfaccs 128, 130 located on opposite sides of a radially inwardly extending cutting tooth 132 having a laterally inwardly .sloping cuttil-g edgc 134 on thc 30 lowor cnd thereof. I:elch cutting tooth 132 has flat ,, ;'', .
'.' ' ~ ' ~236083 circulllferenti.llly spacod axially extending side surfaces 136 " 38 connected by curvcd end surfaces 140 142 which intersect to form cutting edge 134. Each rib portion also has arcuate segment and inner surfaces 144 defining cir-05 cumferentially spaced portions of boro 48. Air passage means 80 are centrally located in cutt;ng tooth 132 and open through surfaces 144.
Each oF the cutting teeth 86 132 extend downwardly in the drilling position from a common plane 146 spaced down-wardly from snrface 148 a relativoly ~hort axial distance.
Each of the air passages 80, 82 begin at annular lateral surface 150 which defines the end of threaded portion 52.
~ir passages 82 extend axially downwardly beyond cutting surfaces 126 with a lowermost portion 152 located radially opposite gaps 120 below lateral surfaces 128 130. Thus gaps 120 provide the additional function of air flow between adjacent onos of the axially extended cutting means. The oppositely curvod side walls 124 form pockets to facilitate collection of cuttings and facilitate flow of cuttings into central cavi~y 48 and upwardly into connector tube passage 50 .
In thc preserltly proferred crnbodiment, the angles of the beveled r;urfaces 98, 100, 128, 130 are approximately 65 degrees from the vertical axis of tho drill bit. The angle of cutting edges 102, 134 15 approximately a3 degrees from the vertical axis of the drill bit.
Fig. 5 i9 a cutaway assombly drawing of the drill bit asnembly o tho presont invention in an assembled configura-tion. Drill string 26 is attachod to bit sub 22 by way of threaded portions 72 of drill sfrirlg 2fi and threaded ..... . _ _ _ . .. , . _ .. _ _ . _ .. _ .--.--.. --.. ---- . - - -12360B~
.
portions 70 of bit sub 22. In a similar manner bit sub 22 is coupled to drill bit 20 by way of male threaded portions 54 of bit suh 22 and femalc threaded portions 52 of drill bit 20. 13i~ sleeve 24 is disposed in the central opening 05 formed by the assembly of drill bit 20 bit sub 22 and drill string 26. sit sleeve 24 is dispc sed between flange portion 32 of innrr piiJC 30 and ~nnulnr sen1 62 disposed in bit ~.ub 22. Bit ;1 ceve 24 forms an annular cylindrical cavity having a center passage 50 for movement of air and collected lO bit samples in an upward direction. ~3it sleeve 24 separates center passage SU from external air passage 42. O-rir,gs 34, 36 provide ar1 airtight geal between outer passage 42 and center passage 50. Air is pumped down the outer passageway 42 of the drill string from the surface and proceeds along 15 the outer passage as indicated by arrows 44, 46. Air passes between the inner surface of annular ring 68 and outer surface 78 of hit sleeve 24 into notched portions 80 82 of cutting tceth a4, a6. Annular ring 62 provides an airti~Jht seal betwcen annular ring 68 and the inn~r wall of bit sub 20 22 ar1û abrorbr shock transn1ittcd by bit sleeve 24.
The co11figuration of air passage means 80, a2 directs the airflow in an inward and upward direction to provide a more consistent air return. Both pressure and velocity of the air rcturn remain more constant during the drilling 25 process bccause of the inward and upward angle at which the air is directr1d throug11 air passages 80, 82. The air medium functions to blow the sample away from the cutting edges of the bit and direct the sample through opening 48 into the void ureu oF ccntrfl] passage 50 such that the sample is 30 directed alony the path of least resistance through ccntral _ _ _ _ _ _ , , _, _ _ _ _ _ _ _,, _,, , . , . , _ , .. . . . . .
1Z360~3 passage 50. In this manner, the consistency of the sample by volume is constant during thc entire drilling process so as to provide a sample of mineral content which remains constant with vertical drilling deptil. This is of high 05 i,nportance in exploratory drillinq especially of desert aluvi~ls and ~lacer exploration to accurately determine mincral content ol :anlplcs to a-cumulate data or the purpose of evaluating the feasibility of a mining operatlo~l.
Failure to c~ficiently and consistently return the sample to the surface nlay affect the accuracy of the perrentage pcr ton of rare metals of the sample retrieved during the drilling process.
Thr- ~Iresent invention also provides extra cutting edge.
The axially .shortened cutting means 90 provides room for lS expansion of samplcs which havr: bcen cut by axially extended cutting means 92 until the sample is removed through central opening 50. The cutting edges are beveled to increase the fecd a1lgle and to :.treamlinc the removal of sample from the cutting surfaces during the drilling process. The angle of the cutting edges provides for more cutting edge as the cutting procc:R pro~eeds into thc cut material. Moreover, the design of the present invention provides for additional cuttiny t-cth to Lurthl3r incroasc he efficir~ncy of the hammer drill hit of the present inven~ion Fig. 6 illustrate3 an alternative embodiment which utilizes carbide inserts 160, 162, 164, 168 adjacent cutting edges in drill bit 20. Each of the cnrbide inserts is inserted into a grrovo such as groove 170 adjacent the cutting erlge and sccured in p]nrc hy gluing or othrc~r suit-able means of attaching the carnide lnserts in the grooves.
.. _ . _ .. ., _ . . .. _ _, ., ., .. _ . .. _ . . .. _ .. _ _ _ _ . . _ _ _ .. _ . . . , .. , _ . _, . . . . .. _ .
:' , . .
~Z36083 .
The carbide inscrts fullction to increase the hardness of the cutting edges and consequently extend the effective use of the drill bit and premature wear of the cutting edges. The grooves in the cutting edges are machined in drill bit 2C
os prior to the hardening process. Once the grooves are machined in the drill bit 20, the surfaces are case hardened by el~ctrical induction, as de~crihed above.
The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, alld other modifications and variations may be pos~ibl~ in li~ht of the above teaching.s.
The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utili7e the invention in various embodiments and various modifications as are suited to the particular use contemplated. It i3 intended that the appended claims be construed to include other alternative embodiments of the invcnti.on except insoear as limited by the prior art.
. _, . ., _ _ .. _ . , . _ _ _ .. _ , .. _ _ _ . ., _ _ . ..... ... ,, . , . , . . . ... ... .. . . . . _ _ _ .
....... . ..
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A hammer drill bit for efficiently and consistent-ly cutting and removing drilling samples in use with dual wall drilling pipe having concentric outer and inner pipe members comprising:
a plurality of axially extended cutting means circumferentially disposed on circumferentially spaced lowermost arcuate segmental portions of uniform size and shape having opposite parallel circumferentially spaced side surfaces forming a plurality of uniform (claim 1 continued, part 2) size and shape circumferentially spaced radially inwardly extending end slots around the periphery of said drill bit between a generally cylindrical outer peripheral surface portion and a generally cylindrical central opening extending axially through the drill bit, each of said axially extended cutting means comprising:
lowermost flat beveled surface means formed on said segmental portions at the lowermost end of the drill bit and extending radially inwardly between said outer peripheral surface portion and said central opening and having an inward and upward slope to facilitate the flow of said samples cut by said axially extended cutting means into a lower portion of said central opening at a first beveled surface means angle of vertical inclination;
lowermost arcuate outer peripheral cutting edge means located at the intersection of said outer peripheral surface portion and said lower-most flat beveled surface means;
lowermost radially extending cutting teeth means centrally disposed on said lowermost flat beveled surface means and having an elongated axially extending portion having an inner curved surface which is concentric with and defines a portion of said central opening and a radially extending portion with a pair of curved side surfaces which intersect to form a radial cutting edge portion extending in a radially inward and upward direction from said outer peripheral (claim 1 continued, part 3) cutting edge means to said central opening at a first cutting tooth angle of greater vertical inclination than said first bevel surface means angle of inclination;
first notched axially extending air passage means formed in said inner curved surface of said first cutting teeth means for directing air in a radially inward and upward direction to provide consistent velocity and pressure of air flow into said central opening to remove samples from the cutting surfaces of the drill bit and direct the samples into said central opening for removal and recovery;
a plurality of axially shortened cutting means axially upwardly spaced from said axially extended cutting means and disposed on circumferentially spaced arcuate intermediate segmental sections of uniform size and shape located axially adjacent and in part defining said end slots and disposed between said opposite parallel circumferentially spaced side surfaces of said lowermost segmental portions, each of said axially shortened cutting means comprising:
intermediate flat beveled surface means formed on the lowermost end portion of said arcuate intermediate segmental sections of said axially shortened cutting means and located between said opposite parallel circumferentially spaced side surfaces of said lowermost segmental portions and extending radially inwardly between said outer peripheral surface portion and said central opening and having an inward and upward (claim 1 continued, part 4) slope to facilitate the flow of samples into an intermediate portion of said central opening at a second beveled surface means angle of vertical inclination;
intermediate arcuate outer peripheral cutting edge means located at the intersection of said outer peripheral surface portion and said interme-diate beveled surface means and extending between said opposite parallel circumferentially spaced side surfaces of said lowermost segmental por-tions;
said intermediate arcuate outer peripheral cutting edge means and said intermediate beveled surface means and said axially extending opposite parallel side surface of said lowermost segmental portions defining said end slots and forming a generally rectangular opening between said axially extended cutting means to allow expansion of samples which have been cut by said axially extended cutting means prior to removal through said central opening;
uppermost radially extending cutting teeth means centrally disposed on said intermediate flat beveled surface means and having an elongated axially extending portion having an inner curved surface which is concentric with and defines a portion of said central opening and a radially extending portion With a pair of curved side surfaces which intersect to form a radial cutting edge portion extending in a radially inward and upward direction from said intermediate arcuate (claim 1 continued, part 5) outer peripheral cutting edge means and said central opening at a second cutting tooth angle of greater vertical inclination than said second bevel surface means angle of inclination;
second notched air passage means formed in said inner curved surface of said uppermost cutting teeth means for directing air in a radial-ly inward and upward direction to provide consis-tent velocity and pressure of air flow into said central opening to remove samples from cutting surface of said drill bit and direct said samples into said central opening for removal and recov-ery; and each of said inner curved surfaces of each of said lowermost cutting teeth means and said uppermost cutting teeth means being concentric with one another and defining concentric peripher-al surface portions of said central opening.
a plurality of axially extended cutting means circumferentially disposed on circumferentially spaced lowermost arcuate segmental portions of uniform size and shape having opposite parallel circumferentially spaced side surfaces forming a plurality of uniform (claim 1 continued, part 2) size and shape circumferentially spaced radially inwardly extending end slots around the periphery of said drill bit between a generally cylindrical outer peripheral surface portion and a generally cylindrical central opening extending axially through the drill bit, each of said axially extended cutting means comprising:
lowermost flat beveled surface means formed on said segmental portions at the lowermost end of the drill bit and extending radially inwardly between said outer peripheral surface portion and said central opening and having an inward and upward slope to facilitate the flow of said samples cut by said axially extended cutting means into a lower portion of said central opening at a first beveled surface means angle of vertical inclination;
lowermost arcuate outer peripheral cutting edge means located at the intersection of said outer peripheral surface portion and said lower-most flat beveled surface means;
lowermost radially extending cutting teeth means centrally disposed on said lowermost flat beveled surface means and having an elongated axially extending portion having an inner curved surface which is concentric with and defines a portion of said central opening and a radially extending portion with a pair of curved side surfaces which intersect to form a radial cutting edge portion extending in a radially inward and upward direction from said outer peripheral (claim 1 continued, part 3) cutting edge means to said central opening at a first cutting tooth angle of greater vertical inclination than said first bevel surface means angle of inclination;
first notched axially extending air passage means formed in said inner curved surface of said first cutting teeth means for directing air in a radially inward and upward direction to provide consistent velocity and pressure of air flow into said central opening to remove samples from the cutting surfaces of the drill bit and direct the samples into said central opening for removal and recovery;
a plurality of axially shortened cutting means axially upwardly spaced from said axially extended cutting means and disposed on circumferentially spaced arcuate intermediate segmental sections of uniform size and shape located axially adjacent and in part defining said end slots and disposed between said opposite parallel circumferentially spaced side surfaces of said lowermost segmental portions, each of said axially shortened cutting means comprising:
intermediate flat beveled surface means formed on the lowermost end portion of said arcuate intermediate segmental sections of said axially shortened cutting means and located between said opposite parallel circumferentially spaced side surfaces of said lowermost segmental portions and extending radially inwardly between said outer peripheral surface portion and said central opening and having an inward and upward (claim 1 continued, part 4) slope to facilitate the flow of samples into an intermediate portion of said central opening at a second beveled surface means angle of vertical inclination;
intermediate arcuate outer peripheral cutting edge means located at the intersection of said outer peripheral surface portion and said interme-diate beveled surface means and extending between said opposite parallel circumferentially spaced side surfaces of said lowermost segmental por-tions;
said intermediate arcuate outer peripheral cutting edge means and said intermediate beveled surface means and said axially extending opposite parallel side surface of said lowermost segmental portions defining said end slots and forming a generally rectangular opening between said axially extended cutting means to allow expansion of samples which have been cut by said axially extended cutting means prior to removal through said central opening;
uppermost radially extending cutting teeth means centrally disposed on said intermediate flat beveled surface means and having an elongated axially extending portion having an inner curved surface which is concentric with and defines a portion of said central opening and a radially extending portion With a pair of curved side surfaces which intersect to form a radial cutting edge portion extending in a radially inward and upward direction from said intermediate arcuate (claim 1 continued, part 5) outer peripheral cutting edge means and said central opening at a second cutting tooth angle of greater vertical inclination than said second bevel surface means angle of inclination;
second notched air passage means formed in said inner curved surface of said uppermost cutting teeth means for directing air in a radial-ly inward and upward direction to provide consis-tent velocity and pressure of air flow into said central opening to remove samples from cutting surface of said drill bit and direct said samples into said central opening for removal and recov-ery; and each of said inner curved surfaces of each of said lowermost cutting teeth means and said uppermost cutting teeth means being concentric with one another and defining concentric peripher-al surface portions of said central opening.
2. The invention as defined in claim 1 and wherein:
each of said lowermost flat beveled surface means extend continuously from the outer peripheral surface the drill bit to the inner peripheral surfaces of the central opening at a common angle of inclination in a common conical plane; and each of said radially extending cutting edge portions extend from the outer peripheral surface of the drill bit to the inner peripheral surfaces of the central opening at a common angle of inclination and are located in a common conical plane.
each of said lowermost flat beveled surface means extend continuously from the outer peripheral surface the drill bit to the inner peripheral surfaces of the central opening at a common angle of inclination in a common conical plane; and each of said radially extending cutting edge portions extend from the outer peripheral surface of the drill bit to the inner peripheral surfaces of the central opening at a common angle of inclination and are located in a common conical plane.
3. The invention as defined in claim 2 and wherein:
said lowermost arcuate segmental portions have a greater circumferential length than said arcuate intermediate segmental sections.
said lowermost arcuate segmental portions have a greater circumferential length than said arcuate intermediate segmental sections.
4. The invention as defined in claim 3 and wherein:
said lowermost arcuate segmental portions and said arcuate intermediate segmental sections having a common radial thickness with concentric outer peripheral surfaces and concentric inner peripheral surfaces.
said lowermost arcuate segmental portions and said arcuate intermediate segmental sections having a common radial thickness with concentric outer peripheral surfaces and concentric inner peripheral surfaces.
5. The invention as defined in claim 4 and wherein:
each of said radial cutting edge portions of said lowermost radially extending cutting teeth means and said uppermost radially extending cutting teeth means being of the same size and shape.
each of said radial cutting edge portions of said lowermost radially extending cutting teeth means and said uppermost radially extending cutting teeth means being of the same size and shape.
6. The invention as defined in claim 5 wherein reversed curved pocket means are formed at the intersection of said lowermost cutting teeth means and said lowermost flat beveled surface means for facilitating collection of the samples and flow of the samples into said central opening.
7 The invention as defined in claim 5 wherein said predetermined first and second beveled surface means angle is approximately 65 degrees from the vertical axis of the drill bit; and said first and second cutting tooth angle are approximately 83 degrees from the vertical axis of the drill bit.
8 . The invention as defined in claim 5 wherein said lowermost and intermediate arcuate outer peripheral cutting edge means have carbide inserts disposed adjacent thereto to increase hardness and limit wear of said outer peripheral cutting edge means; and said cutting edge portions of said lowermost and uppermost cutting teeth means have carbide inserts disposed adjacent thereto to increase hardness and limit wear of said cutting edge portions.
9. A drill bit for use with dual wall drill pipe having an outer pipe member and a concentric inner pipe member which provide an annular outer passage for supplying air to the drill bit and an annular inner sample passage for upward passage of air and sample materials from the ground comprising:
a generally cylindrical body member made of one piece of metallic material and having a generally cylindrical outer peripheral configuration with an upper portion having radially outermost threaded connecting means for connecting the drill pipe to the outer pipe member and radially innermost connecting means for connecting the drill bit to the inner pipe member;
a central generally cylindrical passage means in said body member having a diameter approximately equal to the inside diameter of the inner pipe member far enabling upward flow of air and ground material from the drill bit to and through the inner pipe member;
a first relatively large size counterbore means in said upper portion of said body member for providing a first radially outwardly extending annular surface (claim 9 continued, part 2) having a plurality of circumferentially spaced axially downwardly extending air inlet passages extending therethrough for delivering air to said central passage means;
a second relatively small size counterbore means axially downwardly offset from said first relatively large size counterbore means for providing a second annular radially extending surface for receiving a connecting sleeve means having an inside diameter approximately equal to the inside diameter of the inner pipe member;
a plurality of equally circumferentially spaced axially upwardly extending slot means in the lowermost portion of said body member defined by opposed parallel flat side surfaces and outer peripheral arcuate edge surfaces extending therebetween and providing a plural-ity of equally spaced lowermost arcuate segment por-tions on the lowermost end potion of said body member and a plurality of equally spaced intermediate arcuate segment portions and an intermediate portion of said body member;
each of said lowermost and said intermediate arcuate segment portions having arcuate outer side wall surfaces which are concentric With said central opening and arcuate inner wall surfaces which are concentric with said central opening;
each of said lowermost and intermediate arcuate segment portions having lowermost beveled surfaces and uppermost beveled surfaces which are radially inwardly and upwardly inclined;
each of said lowermost and intermediate arcuate segment portions having an axially and radially inward-ly extending rib portion centrally located thereon;
each rib portion having an axially extending inner curved surface portion which is concentric with said central opening;
a lowermost generally triangular-shape lower end portion having oppositely curved side surfaces which intersect along a radially outwardly extending line to form a radially inwardly axially upwardly inclined cutting edge portion and at a point of intersection circumjacent said outer peripheral cylindrical surface;
and each rib portion having an axially elongated radially inwardly facing slot means in said inner curved surface portion.
a generally cylindrical body member made of one piece of metallic material and having a generally cylindrical outer peripheral configuration with an upper portion having radially outermost threaded connecting means for connecting the drill pipe to the outer pipe member and radially innermost connecting means for connecting the drill bit to the inner pipe member;
a central generally cylindrical passage means in said body member having a diameter approximately equal to the inside diameter of the inner pipe member far enabling upward flow of air and ground material from the drill bit to and through the inner pipe member;
a first relatively large size counterbore means in said upper portion of said body member for providing a first radially outwardly extending annular surface (claim 9 continued, part 2) having a plurality of circumferentially spaced axially downwardly extending air inlet passages extending therethrough for delivering air to said central passage means;
a second relatively small size counterbore means axially downwardly offset from said first relatively large size counterbore means for providing a second annular radially extending surface for receiving a connecting sleeve means having an inside diameter approximately equal to the inside diameter of the inner pipe member;
a plurality of equally circumferentially spaced axially upwardly extending slot means in the lowermost portion of said body member defined by opposed parallel flat side surfaces and outer peripheral arcuate edge surfaces extending therebetween and providing a plural-ity of equally spaced lowermost arcuate segment por-tions on the lowermost end potion of said body member and a plurality of equally spaced intermediate arcuate segment portions and an intermediate portion of said body member;
each of said lowermost and said intermediate arcuate segment portions having arcuate outer side wall surfaces which are concentric With said central opening and arcuate inner wall surfaces which are concentric with said central opening;
each of said lowermost and intermediate arcuate segment portions having lowermost beveled surfaces and uppermost beveled surfaces which are radially inwardly and upwardly inclined;
each of said lowermost and intermediate arcuate segment portions having an axially and radially inward-ly extending rib portion centrally located thereon;
each rib portion having an axially extending inner curved surface portion which is concentric with said central opening;
a lowermost generally triangular-shape lower end portion having oppositely curved side surfaces which intersect along a radially outwardly extending line to form a radially inwardly axially upwardly inclined cutting edge portion and at a point of intersection circumjacent said outer peripheral cylindrical surface;
and each rib portion having an axially elongated radially inwardly facing slot means in said inner curved surface portion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US59583884A | 1984-04-02 | 1984-04-02 | |
| US595,838 | 1984-04-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1236083A true CA1236083A (en) | 1988-05-03 |
Family
ID=24384884
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000477688A Expired CA1236083A (en) | 1984-04-02 | 1985-03-27 | Hammer drill bit and sub-assembly |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1236083A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2404889A (en) * | 2003-08-12 | 2005-02-16 | Black & Decker Inc | A cutting plate for a drill bit |
-
1985
- 1985-03-27 CA CA000477688A patent/CA1236083A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2404889A (en) * | 2003-08-12 | 2005-02-16 | Black & Decker Inc | A cutting plate for a drill bit |
| US7225890B2 (en) | 2003-08-12 | 2007-06-05 | Black & Decker Inc. | Cutting plate for a drill bit |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4323130A (en) | Drill bit | |
| USRE32036E (en) | Drill bit | |
| US6609580B2 (en) | Polycrystalline diamond compact insert reaming tool | |
| US3915246A (en) | Rotary drilling bit | |
| US20190226284A1 (en) | Slide reamer and stabilizer tool | |
| US4385669A (en) | Integral blade cylindrical gauge stabilizer reamer | |
| US4792001A (en) | Rotary drill bit | |
| US6062326A (en) | Casing shoe with cutting means | |
| US5178222A (en) | Drill bit having enhanced stability | |
| US4724913A (en) | Drill bit and improved cutting element | |
| US8162081B2 (en) | Force balanced asymmetric drilling reamer and methods for force balancing | |
| US4494618A (en) | Drill bit with self cleaning nozzle | |
| US4190124A (en) | Stabilizer and blade attachment means therefor | |
| US7025156B1 (en) | Rotary drill bit for casting milling and formation drilling | |
| EP0778914B1 (en) | Drill casing installation equipment with external friction reducing means | |
| CN110671043B (en) | Drilling system and method | |
| US4473125A (en) | Insert for drill bits and drill stabilizers | |
| US7882907B2 (en) | Earth boring bit | |
| US10753155B2 (en) | Fixed cutter stabilizing drill bit | |
| US4739844A (en) | Hammer drill bit and sub-assembly | |
| US4324300A (en) | Rotary drill bit | |
| US4301877A (en) | Clad mud nozzle | |
| US3599736A (en) | Rotary drill bit | |
| AU758430B2 (en) | Roller cone drill bit structure having improved journal angle and journal offset | |
| US5372209A (en) | Polycentric reamer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |