US1828604A

US1828604A - Hydraulic drill

Info

Publication number: US1828604A
Application number: US738672A
Authority: US
Inventors: Ira B Humphreys
Original assignee: Individual
Current assignee: Individual
Priority date: 1924-09-19
Filing date: 1924-09-19
Publication date: 1931-10-20
Anticipated expiration: 1948-10-20

Description

Oct 20, 1931. Y B. HUMPHREYS 1,828,604

HYDRAULIC DRILL Filed Sept. 19, 1924 2 Sheets-Sheet l J5 Z' 19 @5w y @a 311s 6W J i6 "#9 a] 6 -ff W lIN 4 a ,Mmm 1, l s y wfg-)yn s m. l j; i: l l f C .Z22- will@ l, ,jg 136 n] f F @i dgn dus, I

4 a 1f 7, ',4 Lmlx iff clllV'll'f"y L04 ,2 9 f Ml @ggf gy `l`z a NIM qz'ii if y, Ms N i f a "Q 43 a9 C 2 L? IMI( n y f l f, lag; if;

HYDRAULIC DRILL Filed sept. 19, 1924` 2 sham-sheet 2 Bjiasz-:forinstaneevthe ril-lin p p Hretofore Yirndeepwell-f rillihgitthasbeen@ the? practicetefuse:either'cableoperated drills.:y

mns-nummers;ioznmwmifcoow I f1 nnmunxemnmf.

Appiicmanfrmeeiseptember, .1s,1. 1s24.- smul m1138572.

stem is used extendL lf'rmgithe? :bottoms ofif the well, where rthefrworleisbeing1-donet'othef to 1, ofi theawell vcfherexfsuit'a.bl/e1"ineens:areapro@ vi edsforfrotetingg-,theestemr.Thesefmethodsffs o-y drilling;present-ga; pr0bl`em;a,s;the; cablesaora A the dri'lllf l.'st lerna:einen become-1: brokenL-which; necessittessthe@pulliiiggofthefdrillifromatheg@ welllv casingxv-andrlishingf for-fthe'. lo'etapairtv ofcV 'l theidrill; left in'ithewvell' clueQ-togthei breakage-.3

tion will appear* in nthe following'j description breakageazoccursfth -.thefzresultlfs the :lossJz-olffFi-'anda` acompanying drawingsr 2if''considem-adele tim'efzi Twith'f. azf .resultnt trouble: r

andexpenseae,

Onezof thek drill stemsf.

A further1objectfortheinventiomis;to:pre1?, vide fa.combinedf:hydraulictspringyoperated,'l drill: of va., `,construction-i whereby` the entire drilling,mechanismisilowered;intoatheefrwella'f casingzatothe Apoint-1'wherethcmajctuelwork ist Anctheriax'lfdlfrther. object.aotE-` `the invenf tion n-f istoiprovidezmcombinedhydraulic. and; springvaoperatedfdrillfr;:deepwelkdrillingip A.stilliurthereobjectfjofthe invention 'is'.tofg provide 5f;.ai:combinedr'hyidraulic and v `'springer-- operaterldrill?A nwhich-the -fhydr'aulic lpres'-l A sure rislusedbotlntoi'operate'the `drill andi.A to

washtheg;cuttingsfffrcmrthe well., v

Anothertohje `'vide afhydraulic drill in which the len :eff: .theiinvention .is to' pro-f .constructionif lof. hydraulic l f drill? wherebythe? numbered-operating f parts. are -few,= reducngthezzweight ofthedevicel asy aewhole; and; to'l epply-theepower to the" .drill-:.1 infsuch-f-aJ manner asy tozreduce to a,v minimum.: the; recoiland?!vibration;of the.,devicef;whi`ch. partlafrotary movement tothe drill.

' 'llh-isy i'nventionereltesfto;improvements/inf, wouldtend-toflift orl lstrain, the device inany rauhe drills?"pertainngmore:particularly dreuli "andsprin foperatcdsv i provide a novel lmeans in a'hydraulic drill otite-partes A Astill further objectofthe invention is to.

for :controlling and directing the hydraulic pressure to'operate ther device inthe desired.

and, springoperated drill which` isv .simple pit construction andhighly eicient inoperaonkl l v Another object of the vinvention is to.

thestroke. is variable as desired. Y Other further objects, novel features kof construction and improved resultsy of thev inven'' l.

Imthe drawings: Figurel isa, vert-ical-sectional'view of the beings own: lowered withinfa well casin F1?. y3 isan venlarged* detailv verticalsecf view of the` vulve constructionof the r f.. v

Fig.- 4 lis e:fragmentary enlarged verticaly sectionalview showing the manner in which n lthe lret-aiming ring issupported in the drills` in rxmechanism.l

ig. 5 is `en enlarged vertical sectional view showing they one-way clutch.y

Fig, -6 is. a transverse*sectionalv view taken onthe line 6---6,fliigg,5'.v v

upper ort-ionvofthe drillf,the.-mechansm Fig. V7 is ,a transverse sectionalview, similer-*tof Fig..16, showings, modified form of -u drill'head-against theV .tension of a spring and '95! n atea. predetermined time to balance the hy- 'dr'auhcjpressure within the mechanism to al- 'low the .drill bit and headto be driven down.-r

wardly by the energy stored in.: the *com-n pressed spring and tey provide .means to imbroadlly com rising a valve housing A, a cylinder ton D a drill a ho low plston rod C carrying a pishead G.

The drilled hole or well is designated by-f the numeral 5 and as is common in the drilling of wells a well casing 6 yis lowered into" the hole as the drilling rogresses. This well casinfr extends above t eto of the well hole 5 an is provided-wah a @ad 7 with which communicates an inlet pipe or conduit 8 through which is pumped or otherwise suitably forced by an engine or the like (not shown) the hydraulic pressure fluid used in the operation of the drilling mechanism. The well casing head 7 is provided with suitable means 9 which rmits the casing to be lowered as the drilling progresses or to be lifted from the well when desired. The well casini head 7 is further provided with a remova le top or cover 10.v

The valve housin A is closed at its top by a head 11 while its ower end is open and adapted for communication with the cylinder B. The cylinder B comprises in reality an elon ated pipe, the upper end of 'which `is 'suita ly attached as at 12 to the valve housing while the lower end of the cylinder screwthreadedly jor otherwise suitably carries the lower cylinder head E.

The cylinder head E is provided at its lower side with an extending sleeve 13 terminatin in a head 14 which screw-threadcdly or oterwise suitably carries the concentrically arranged

pipes

15 and 16. The pi e 15 is the outer pi e and extends downwar ly a much greater istance than the inner ipe its lower end 17 screw-threadedly carrymg a pipe 18 the lower end of which in turn screw-threadedl carries a pipe 19. e

he lower end of the well casing 6 carries a sleeve 20 provided with an inwardly extending circumferential flange 21. The entire drilling mechanism is supported upon this flange through the engagement of the lower end 22 of the pipe 19 with the flange. The hollow piston rod C extends from within the cylinder B, down through the cylinder head E and its extension sleeve 13 and head 14, throughthe

pipes

16, 17 and 18. The lower end 23 of the hollow piston rod screwthreadedly carries as at 24 the drill stem F.

Within the cylinder B the hollow piston rodC is provided with :the piston D which is adapted vto reciprocate wit 'n the cylinder.

a cylinder head E, a drill stem F As clearly appears the piston rod has an ex'- tending end 25 above the piston and this extending end is provided with ports or openings `26 which are in communicationv with the cylinder B while the lower end 23 of the hollow piston rod is in communication with the channel 27 extending the vvlength of the drill .stem F. `The channel-27. extends downwardly through the drill head' G terminating vin outlet openings 28.

Againreferring to the pipe 16 which is the inner of the two concentrically arran ed pipes, itwill be seen that the lower end of t is pipe screw-threadedly carries as at 29 a sleeve 30 provided at its lower end with an inwardly extending circumferential ilange or shoulder 31'. Carried between the flange 31 and the lower end 32 of the pipe 16 is a s linted or spirally threaded nut 33. It will e seen that that portion of the hollow piston rod C which passes through this` splinted nut is provided exteriorlywith spiral threads 34v or the like. e

This splinted nut is provided for the purpose-of rotating the hollow` piston rod and the drill stem-andhead. y It will be readily seen that the nut is locked against vertical movement. The nut 33 is furthermore provided with some common form of clutch such as appears in Figs. 5 to 7 inclusive construction whereby it is locked against rotation on the u ward movement of the hollow piston rod 't ereby lcausing the rod to rotate. The clutch arrangementof the'nut is such however 'as to allow it to rotate on the downward movement of the iston rod land consequently theA piston rod, ill v,stem and hea'dar'e'not rotated through 'their downward movement.

Surrounding the piston rod C between the splinted nut 33 and the enlarged portion 35 adjacent the end of the piston rod isa spiral spring 36. The u per end of'this spring en-l gages the lower si eof the collar or sleeve 30 while the lower end of the spring engages the enlarged portion 35'of the drill stem. It will be seen that any upward movement of the piston rod will cause thisspiralor coiled spring the members mentioned a space or channel-37. yAdditionallyit will ber seen that the well cas-vI atv ion

ing does notfit tightly. the well or` drilled hole 5. e y W Within the valve housing A lis a

sleeve valve

3,8`prov1ded at its lower end with an en- `largedjhead 39 :adapted to seat upon the taofthe-.cylinder B. i l i-I ringmediately above the ``valve seat 40 the cylinder isfprovided withports'41 which pered valve seat 40 carriedby the. upper end masser are in vcommunication with the interior ofthe well casing 6 and are hkewise in communication with the interior Aof the valve-housingA when the vvalve 38v and its enlarged head 39 is cient s1ze to accommodate the well casing and lifted.4 TheA upward movement of the valve is limited by the shoulder 42 of the valve head coming into engagement with the lower end of the valve housing while the downward movement of the-valve is of course limited by thevalveseat40.v

Suitably fastened within the extendingend 25 of the hollow piston rod Gand closing it is a valve rod 43 which'4 extends through the sleeve 44 of the valve head 39, terminating within the valve housing in an enlarged head 45. Surroundin the valve rod 43 between the u per end o the .valve head sleeve andthe en arged head 45 of the rod is a coil spring'4.

A second coil spring 47 surrounds the valve stem 43 withln the cylinder` B. This spring rests upon the upper end of the hollow piston rod and the upper end of the s ring is adapted for engagement with `the s eeve 44 of the enlarged valve head 39.

The cylinder B is rovided at its lower end with a port 48 w ich is in communication with the well casing channel 37.

The drill stem F is provided with an enlarged head 49 at its upper end. This head however is of a size which would permit its assage through the sleeve 20 carried by thellower end of the well casing. From this it will be seen that in the event the drill stem became broken it would be possible to lose the drill in the well hole. To guard against this there is provided a split ring 50 which rests upon the shoulder 51 adjacent the upper end of the pipe 19. In the event that the threaded connection 2 4- of the drill stem with the lower end of the piston rod becomes dis-connected or broken it will be seen that the split ring 50 will engage the head 49 of the drill stem and prevent the stem from dropping from the pipe 19 or the well casing.

To permit the drilling of a hole of sufliat the same time provide a construction of drill head which will allow the head to be drawn upwardly through the well casing the head is provided with under-reamers l 52. These under-reamers are of a common f construction, being pivotally mounted at 53 and normally held in their expandedpositions due to a spring 54. As the drilling .-H mechanism is pulled' from thewell casing f these under-reamers will spring inwardly against the tension of the coil s ring 54 and 6ov thereby permit the passage of t e drill head through the well casing.

A wei ht 55 is suita ly mounted upon the i to of t e valve housing A. This weight ho ds the entire drilling mechanism in place upon the shoulder 21 of the sleeve 20 at the lower end of the well casing. This weight 'i dr1ll head.

Suitably fastened within the wei ht 55 is a cable 56 which passes upwardly t rough a stuing box 57 or some like littin to a point above'the well. It will be readi y apparent that upon removing the cover 10 of the casing head 7 that the entire drilling mechanism which includes the valve housing A the cl linder B, the ipes 16 17, 18 and 19 and Athe rill bit F, and) head (il can .be removed from the well casing. This arrangement is very important as it permits the ready and rapid removal of the drilling mechanism from the well to effect any repalrs or adjustments and likewise ermits the rapid installation of the drilling mechanism as it is only necessary to lower the mechanism until the lower end of the pipe 19 rests upon the flange 21 at the bottom of the well caslng.

It will also be seen that due to the manner in which the drilling mechanism can be lowered into the well 'casing and removed from the casing that the entire mechanism can be assembled on the ound above the well. This of course woul be necessary because the split ring 50 would vhave to beplaced in position before the pipe 19 is screwfi into place upon the lower end of the p1 t is not thought necessary to go further in the assembling of the drill as this can be readily accomplished byanyone skilled in the art as the drill is not at all complicated, it being merely necessary to position the proper parts by screwing them into place in their proper positions as shownl in the drawings. l

Operation The fluid which will preferably be used as the motive power for the drill will be water as is common in rotary drilling.

This fluid will be forced under high pressure, by some suitable engine or the like, into the inlet 8 in the head of the well casing.

With the parts as shown in the figures of the drawings the piston D is about to start its upward stroke.

The highpressure Huid passing down the well casing in the space 37 enters the port 48 at the lower end of the cylinder B and causes an upward'pressure upon the piston. As the piston ascends it carries with it- 'the hollow piston rod, and the drill bit and drill head, all of whi'ch are in operative'engagement. It will be seen that as the/piston rises it also carries with it the valve rod 43 which is fesin as it adds to the impact stroke of the v the channel 27 in t tened in the upper open end of the piston ro The fluid in the cylinder B above the pis- -tonv is discharged through the piston rod orts 26 as the piston ascends and passes downwardly throu h the hollow piston rod, e drill bit and outwardl through the channel 28 in the drill head, fbrcing the cuttings upwardly out of the .well on the outside of the well casing.

It will be also seen that due to the upward movement of the piston and piston rod that eventually the coil sprin 47 surrounding the valve stem will engage t e ortion 44 o the enlarged valve head 39 an force the sleeve valve 38 from its seat. This valve is so made that very little pressure is required to raise it from its seat. It will be understood thatv hi h pressure fluid is constantly on the outsigo `of the valve head and the valv(` is therefore held on its seat until raised bythe action of the u ardly moving piston rod and the spring 4%. It will also be understood that as the piston ascends the coil s ring 36 is com ressed between the enlarge piston rod lportion and the sleeve 30 which holds -the splinted nut 33 in place. t

When the piston has reached the top of its stroke the sleeve valve has been lifted from its seat and high pressure is allowed to enter the ports 41 and flow downwardly beneath the valve head into the cylinder B above the pise ton. This high pressure likewise enters the Hrl valve housing A through the open end 59 of r the sleeve valve.

It will now be seenthat high 'pressure is acting on both the u per sideof the piston A and on the lower si e of the piston, as the ports`48 are always open, and is balanced.

As the drilling mechanism has ascended th drill stem and head have been rotated due to the 4splinted nut 33 and the spiral teeth 34 on the exterior of the hollow piston rod.-

The piston, piston rodz drill stem and drill head will now start thelr downward stroke the driving power being spring 36l As the piston descends the piston rod, drill stem'anddrill head are carried downwardly but are not rotated because the clutch of the splinted nut operates to release and allow the slinted nut to rotate as the piston rod passes t rough it. r

As the piston continues to descend the fluid the compressed coil in the cylinder belowr the piston is forced out'- wardly throughthe ports 48 up the well casing.

It will also be seen that as the piston descends that eventually the enlarged head of the valve rod will engage and compress the coil spring 46 which will, after being suiii- -ciently compressed overcome the pressure on the valve head 39 and cause the valve to seat and thus cut ol the high pressure iuid being 5 delivered into the .cylinder above the piston.

` The downward movement'of the piston andr drill is rapid so-thatthe ydrill w1ll strikeY the bottom of the well' or hole'forciblysstrikin'g or -dilerent'-positaonon` each stroke due to the fact'that'the drill headA in a different place is rotated during its upward movement.- Y

and downward 'strokev of thedrilla-n'dcoi-actY ing 'partshas been described;r 'Ihetupward stroke of the drillis now ready to begin iagain and is merely la repetition-ofthestroke.here-- tofore described. 1

It will ofcourse be-understoodthatfasthe ,drillingproresse's the well casing is lowered.A

lioweverthe 'lowerfend of the well' f At all tlmes casingris' above the `bottom 'offthe well or' hole 'bein drilledrl It has been heretofore length of thestroke of the dri-llis'fvariable.

This is accomplished through vthe medium of the well casing as it will be clearlyf'seen that the length of' the downward stroke. of the drill is controlled entirely bythe distancethe lower end of the well casin l'is above the'bottom. of the hole being dri led; -Toshorten the stroke of the drill it is only necessary to lower the well' casing until its lowerfend is quite near the bottom of the holei l The action of the valve to'changezthe direction of movement of the piston. is automatic and will act immediatelyupon theim- Ract of the drill head with the bottom of the ole irres ective ofthe lengthvo the'down'- ward stro eof the drill.- Q i j With the valvepin la closed position the Huid under pressure-from the lpressure pro viding mechanism' above orlad'j acentthe well of the valve is acting on a greater areal and exerting a downward force thereuponthan the area subjected to the upward pressure and, furthermore the pressure or'headfof the fluid acting to li tthe valve fis less thanthe pressure or head of the fluid exerting an upward pressure u onthevalv'e, forth'e reason that what little uid is present 'above thel iston at the time the piston starts u'pwar is being discharged through 'the hollow drill bit or stem as the pistonisraised. v

When the'spring 47 presses'up'ovn tli'vglye 1 guide fins Asuiici'ently to overconiefthe unbalanced pressure on the Vvalvevvliicliiisholding the valve-closed,`the valve willv openarid the high pressure iiuid' entering thef ports 41 will pass under the valve and into the cylinder above the piston. The extensinfbelow: the "l" .mentioned thatV the n'lfm A complete reciprocation of afull upward cylinder.

' nism will be pulled from the Losanna valve carrying the fins partly fills or obstructs the opening through the valve seat and, hence, forms aA restriction. through which the hi h pressure fluid must pass to get into e When the valve is opened,cthe downward movement of the 'drill and piston is very rapid, due to the ener stored in the driving spring 36 and thus t e area of the cylinder ,above the piston into which the fluid is liowing is rapidly increasing. Furthermore the passage of the fluid through the restriction causes a material acceleration of the speed of flow of said Huid and causes what might be termed an ejector action in respect to the passageways 59 in the valve thus preventing a building up of pressure in the valve housing above the valve in an amount equal to the pressure head existent under and acting up- .wardv upon the valve head 39. Due to this differential of pressure the vvalve remains in its open ostion until the downward movement of t e piston is arrested.l

When the piston for any reason stops its downward movement the flow of fluid beheath the valve and throu h the restriction is reduced, infact, racticay stopped so that the pressure hea in the restriction, in the chambers below the valve and above the valve are practically the same as exist adjacent the ports 41 and above the restriction. The pressure head acting upwardly and downwardly upon; the valve are practically balanced and the spring 46 acts and closes the valve and the entire operation begins over again.

From the foregoing 1t will be seen that the a paratus isautomatic insofar as reversin t e direction of movement is concerned an that its work will be continuous as long as 4 hgh pressure fluid' is supplied to the well casing inlet 8.

It is proposed that in practice that the well casing which is used durlng the drilling operation will be left in the well after it has been completed. The entire drilling mechacasing for use lupon another '0b. f

It will be a ditionally seen from the foregoing description that a combined hydraulic and s ring operated drilllng mechanism is provi ed which can be readll and quickly lowered into the hole being rilled, or removed from the hole, and that as the drilling takes lace, the cuttings are washed upwardly ancyoutwardl from the hole.

Having thus dyescribed my invention what I claim and desire to secure by Letters Patent is 1. A drilling machine, comprising a drill, a reciprocatinglpiston for imparting movement to said dr' means for supplying liquid pressure and said liquid pressure acting on said piston, means to alternately direct a portion of, said pressure above said piston, 5 and resilient means compressed by said piston and the drill for direction,

2. In a drilling machine, an inner and an outer pipe, a reciprocating member within the inner plpe carrying a drill, means for supplying liquid pressure and said pressure communicating with one of said (pipes above said reciprocating member, an reciprocating means above said reciprocating member for alternately directing a portion of the 'pressure above said reciprocating member to balance the pressure above and below the same.

3. In a drill, the combination with a cylinder carrying a piston adapted to be reclprocated and thereby impart movement to the drill, means for supplying liquid pressure to said cylinder, means to alternately direct a portion of said pressure above said piston,

driving said members in one and resilient means for driving said piston A and drill in one direction arranged to be compressed b the upward movement of the pis-l ton and ill.

4. In a drill, means for supplying liquid prewure to said adapted for reciprocation in said cylinder and provided with a piston rod carrying al drill, said pressure acting constantly on said liston to lift the same, means to alternately 'rect a portion of said pressure above the said piston, and resilient means compressed by the upward movement of said piston and adapted to drive said piston downwardly at a predetermined time.

5. A drill, means for supplying liquid pressure to sai'd drill, comprising a cylinder, a piston adapted for reclprocation in said cy inder, a hollow piston rodfor said cylinder carrying a drill, said pressure acting constantly on said piston to lift the same, means operated by the movement of said piston for alternately directing a portion of said pressure to act upon the opposite side ofsaid piston, resilient means compressed by the upward movement of said piston, and said hol low piston rod in communication with the cylinder above said piston, whereby the high pressure is discharged throu h the said piston rod on the upward stroke o vthe piston. n

y 6. In a pressure drill, a reciprocating piston in operative engagement with the drill, pressure means providing pressure acting constantly to lift said piston, means separate drill, a cylinder, a piston c and distinct from sald piston to divert a ortion of said pressure above the piston to alance the pressure upon the same, andi meals to drive the piston and drill downwar 7. In a drilling mechanism, a reci rocat- 8. In a drilling mechanism, a reciprocating piston in operative engagement with the drill, a cylinder for said piston, fluid pressure providing means, fluid pressure acting constantly on said piston to raise it, means to balance the pressure above and below said piston, means to drive said piston and drill downward, and means operating said fluid pressure balancing means at the time of the drill impact to direct the entire fluid pressure upon the lower side of the piston to lift the drill.

' 9. In a fluid pressure loperated drilling mechanism, a cylinder having a piston adapted for reciprocation therein, a hollow piston rod connecting ,the iston and the drill, means for providing uid pressure to the cylinder to lift the drill, separate means for driving said `drill downward, and communication between the cylinder and the hollow piston rod, whereby on the up stroke of the p'iston the fluid in the cylinder is discharged through the hollowpiston rod and washes out the cuttings ofthe drill.

10. In a drilling mechanism, a drill and drill stem having internal passage-ways with outlets adjacent the drill end, a piston having a hollow rod having connection and communication with the drill stem passage-Ways,

fluid pressure providing means for providing pressure to opposite sides of said piston for actuating the drill, a cylinder for said piston,.and the hollow piston rod in communication with the cylinder above the piston, whereby the fluid above the piston is forced down the piston rod and outwardly through the drill on the upward movement of the piston.

11. In a pressure drill, a reciprocating piston in operative engagement with the drill, pressure means providing pressure acting constantly to lift said piston, a valve separateand distinct from said iston to divert a portion of said pressure a ove the piston to balance the pressure upon the same, and means to drive the piston and drill downwa-rd` 12. In a pressure drill, a reciprocating piston in operative engagement `with the drill, pressure means providing pressurel acting constantly to move the piston in one direction, a valve to divert a portion of said pressure to balance the pressure upon the pist0n,.separate means to drive the piston in the opposite direction; and a spring moving said valve to a closed position immediately v upon the impact of the drill.

13. In a pressure drill, a reciprocating piston in operative engagement with the drill, pressure means providing pressure. acting constantly to move the piston in one direction, a' valve to divert a portion of said pressure to balance the pressure upon the piston, said valve normally closed, means actuated by the piston to open said valve when the piston is at one end of its stroke, separate means for driving the piston in the opposite direction, and means closing said valve immediately upon the impact of the drill.

14. In a pressure drill, a reciprocating piston in operative engagement with the drill, pressure means providing pressure acting constantly to lift said piston, a valve operated by the upward movement of the said piston for diverting a portion of said pressure above the piston to balance the pressure upon the same when it has reached the end of its upward stroke, means to drive the piston and drill downward, and a s ring for closing said valve and the inlet o pressure above the piston immediately upon the impact of the drill.

1`5. In a pressure drill, a reciprocating piston in operative engagement with the drill, pressure means constantly providing pressure at one side of the piston to move the same in one direction, a valve operated by the movement of said piston to direct a portion of the pressure to the opposite side of the piston to balance the pressure at the opposite sides thereof, and resilient means to move said piston and 'drill when said pressure is `balanced on the opposite sides of said piston.

16. In a drilling machine, a pair of concentrically arranged pipes, a reciprocating piston movable in the lnner pipe and having operative engagement with a. drill, a valve at the upper end of said inner pipe and normally closing said ipe end, means for providing and delivering fluid under pressure to the outer pipe, constant communication between said inner ipe and said outer ipe below said piston ibr the admission of uid under pressure, said piston movable u ward by said fluid pressure, said piston a apted upon its upward movement to engage and open said valve and permit the admission of fluid under pressure above said piston, resilient means to move said piston and drill downwardly` when said valve is open, and said valve automatically closing upon the impact of the drill and the stoppage of downward movement of the drill and iston.

17. In a pressure drill, means or supplyl,.:u'

ing liquid pressure to said drill, an inner and an outer pipe, a drilling mechanism within the outer pipe, a reciprocatin member Within the inner pipe carrying a ill, said pressure communicating with one of said pipes V abovev said reciprocating `member, a valve movable by the movement of said reciprocating member for directing the pressure to balance the same at either side of said reciprocating member, and resilient means for driv- 125 ing said reciprocating member Vwhen said pressure is balanced as described.

18. In a pressure drill, a reciprocating piston in operative engagement with the drill,

pressure means providing pressure acting constantly to lift p ated by the upward movement `ofksaid"`pis ton diverting a portion of saidjpressure 'f above thepiston tobalance the pressure u on said piston,y means operthe same when it has reached the end o its upward stroke, means to drive the pistony and drill downward, and means for actuating said-` pressurer diverting/ means to prevent the` inlet of pressure fluid above 'the piston immediately u on the impact of the drill.

In testimony w ereof I hereunto aix my signature.

IRA B. HUMPHREY S.

y nu