US1597143A - Expansive and cqntbactive odeep-wbll brill - Google Patents

Description

Aug. 24, 1926. 1,597,143

o.l M. CARTER EXPANSIVE AND CONTRACTIVE DEEP WELL DRILL Fle July e. .1922 5 Sheets-Sheet 1 fipa l al i l 4Z :NVE/WUR Osea/'M Caz-en A TTOH/VEYS Mms ugn 24 9 1926e O. M. CARTER.

ExPANsIvE AND CONTRACTIVE DEEP, WELL DRILL Filed July e, 1922 WTNESSES Aug. 24 1926. 1,597,143

O. M. CARTER EXPANSIVE AND CONTRACTIVE DEEP WELL DRILL A TTORNEVS Aug., 24 19@o M. CARTER ExPANsIvE AND coNTRAcTvE DEEP WELL DRILL 5 ShwtEa-Sheet 4 /NVEIVTH A TTORNEVS f lilya. 1922 Filed J prematurely released.

Patented Aug. 24, 1926.

UNITED STATES l I1,597,143 'PATENT nieuwe.

OSCAR MARTIN CARTER, @F HUSTON, TEXAS.

EXPANSIVE ANSI)` CONTRACTNE DEEP-WELL DRILL.

Application led July 6,l

This invention relates to expansive and contractive deep well drills especially adapted for use in drilling oil and other wells and is an improvement on the construction illustrated in my United States Patent No. 1,412,- 101 issued April 11, 1922 and my other patents in this art.

Briefly stated, this invention aims to provide a'deep well expansive and contractive drill having simple means whereby the cutters or bits are automatically moved to their operative positions with relation to the drill stem when the same reach the limit of their downward movement.

Further the invention forming the sub- .v ject matter of this a plication aims to provide novel means whereby the pressure on the bits is absolutely prevented from collapsing the bits, the said means being in the nature of a plurality of locking devices, all of which are more or less independent of each other and which mutually contribute to successfully hold the bits in their operative' positions. l

A further 'object 'is to provide` a novel means whereby excessive friction on the downward or upward movement of the underreamer is prevented and the invention is also provided with simple means whereby the lowering cable'is prevented from being A further aim is to provide an expansive and contractive drill having a lurality of ball and socket joints which ena le the drill to conform to longitudinal bends in the drill stem.

An equally important object of this invention is to provide simple means whereby the bits'are securely though detachably connected to the bit holder in such a" manner that the saine may be quickly detached when the drill is brought to the surface for the renewal of the bits..

Other objects and advantages of the invention will be a parent during the course of the following lescription. j

In the accompanying drawings, torming a part of this application and in which like numerals are employed to designate like parts throughout the same, s

Fi re 1 is a side elevation of the drill within a drill stem, the same being shown in the osition it occupies during the re'- moval t ereof, and parts being shown in section. I

I Figure 2 is a vertical detail sectional view eration, the bit carrier being shown part 1922. Serial No. M3153.

through the drill, the saine being shown within the lower portion of the drill stem collar. j

Figure 3 is a detail sectional view illustrating the drill stem collar and the 'specific means employed for guiding the bit holders into locking engagement with the lower portion of the colla-r.

5 Figures 4 and 5 are `side elevations of the improved drill completely collapsed, parts of the drill being shown in section.

Figures 6 and 7 are side elevations illustrating the position assumed by the various parts of the drill during its descent through shown partly in section. c

f Figures 8v and 9 are elevations ofthe improved drill, tlie parts being shown in their operative positions ready for the drilling opin section.

Figure 10 is an elevation of one ofv the locking pawls, the same being employed tor locking the bit operating rack to the bit carrier, whereb to prevent collapse of 'the bits as'the res t of end pressure thereon;

,Figure 11 is an ed e elevation of the locking awl illustrat inr Figure 10, one of whic is located on each side of the rack.

Figure 12 is an end elevation illustrating the lower end of the bit carrier, parts of the same being beveled for the passage of mud pumped down through the drill stem during drilling operation.l

Figure 13 is a fragmentary side elevation illustrating the .means for connecting the 'drill to the lowering cable or member, the

view also illustrating the means for releasing the lowering cable or member when the drill has reached the limit. of its downward movement within the drill stem.

Figure 14 is a fragmentary perspective illustrating the means lfor connecting the drill to the lowering cable.

Figure 15 is a agmentary, pers tive 4of a pairof sectional weights embo ied in the invention, which sectional 4weights-act to y move the bitsto their operative` positions. j Figure 16-isan elevation `of one of thebit holders, the bit carried thereby, and an opf e'rating link connected to the bit.

Figure 17 is a" side yelevation of the bit holder the view bein taken from the opposite side from that il ustrated in Figure 16.

Figure 18 is a side elevation of a rack em-' bodied in the invention.

7.0 the casing, the carrier of the drill being j Figure 19 is anedge elevation of the rack illustrated in Figure 18, the same being connected to the bit holders for moving the same to their operative and inoperative positions.

y Figure 20 is an edge elevation of the main v portion of the controlling bar or mandrel embodied in the invention.

Figure 21 is a side elevation of the same,

Figure 22 is a side elevation of the bit carrier.

Figure 23 is a side elevation of the drill stem collar and the lower portion of the drill extended through the collar, parts being shown in section. y

In the drawing wherein for the purposeof illustration is shown a preferred embodiment of the invention, the numeral 5 designates a tubular carrier the forward portion of which ivot'ally supports a pair of bit holders 6 t rou h the mediumof pivot pins 7. Figure '22 1 lustrates that the forward portion of the carrier-5 is rovided with opo'sitely arranged slots 8 t rough which the it holders pass when thesame are extended to the' positions illustrated in Figure 9.

With reference to Figures 9, 16 and 17 it will be observed that a bit 9 is detachably connected to each bit holder through the me' `dium of a fastening bolt or member 10y and one side of the bit holder is undercut to provide a beveledshoulder 11 which securel and pcsitivelyprevents movement of the blt with relation to the holder and also reduces the number of necessary fastening devices 10 to one.,V The bit 9 has one edge beveled for en agement with 'the undercut edge 11 of the ho der and the bit isthereby securely and positively held in tends for a slight istance beyond the for ward end of the holder and is providedwith beveled edges for engagement with the bot-- tom of the well. l

The rear ends of the bit holders 6 are provided' with curved shanks 13 to which operating links 14 are pivotally connected as indicated at 15 and by reference to Figure 16 it will be observed that the forward p0rtion ofthe link 14 is cut away so that the same may overlap the shank 13 in the mannerillustrated in Figure 17. y The link 14 is shown vin Figure 17 in the position it occupies when `the bits are fully extended and vthe link is provided witha transverse groove 16 which registers with a groove or socket 17 in the bit Vholder for the reception of the tapered forward end 18 of the main controL. `ling bar 19 which as illustrated in Figures 5, 7 and 9 asses centrally through the bit carrier 5. v len the controlling bar 19 is advanced the forward end 18 of the same is received within the grooves 16 and 17 so as to lock the bits, of which 4there are two. in,

the operative position as illustratedV in Fig.

9. It is thus seen that when the forward endv '1.8 is received within the osition. The .bit 9 ex-l oves 16 and 17 the bit holders are posltively prevented from'collapsing as a result of pressure thereon. 4

Figures 5, 7 and 9 illustrate that the rear 70 ends of the links 14 are pivoted to y,racks 20 movable longitudinally within the carrier 5 f and connected by cross bars 21, 22 and 23. v The main controlling bar 19 is extended a substantial distance abovethe carrier 5 75 and forms a supporting means for the drill and when it is -desired to, collapse the bit as illustrated in Figures 5 and 7, the controlling bar 19 is moved upwardly so that. the oppositely arranged 'projections 24 on the .B0 same will be engaged'with the cross members 22 of which there are two, and this will move the racks upwardly. Also the mandrelv or controlling bar 19 -s provided in its forward portion wlth a longitudinal slot 25 for the .35

lreception of-a stop pin 26 carried by a cross bar 27 rigidly secured to the carrier. When -the 4supporting means (to be later described) is engaged with the operating or controllin' bar 19 and the bit is lowered into thewe 99 the -stop 'pin will be engaged with the bottom portion of the slot 25 and the weight of' the racks 2() will cause the bit holders 6 to expand to the position illustratedin Figure v 7. However, as the bit descends into the well and reaches an enlarged part of the drill stem to be later described the bit holders will be freeto move outwardly and yconsequently the racks 2O will descend further ori move downwardly with relation tothe main '10 controlling bar 19.

When the racks 20 are thus moved downwardly with relation to the controlling bar a projection 3() formed on one of the racks will engage a holding dog 32 and swinggthe 105 same laterally on the stop pin 26. That is to say the holding dog 32 is pivoted to the stop. pin 26 and when the rack 30 descends the up er portion of the dog will-be moved lateral y from beneath a lug 31 onthe con- 110 trolling bar 19. This releases the main controlling bar and permits the same to descend. yFigure 7 illustrates that when the bit holders are partly open a lug or actuating member 33 on the cross bar 21v engages a shoulder 115 34 on the intermediate portion of the dog and thereby holds the dog in a set position. p However, the holding lug 33 advances with the rack 20 and thereby releases the dog 32- for movement to the right. l l." 120 As'the racks 20 advance the `main controlling vbar 19 willppartake. of a similar movement and' the projections 24 will en. gagethe upwardlydirected terminal portions 35l of a vrpair of oppositely arranged 125e locking'pawls 36 and'swing the locking pawls on their pivots and into openings or notches 37 in opposite sides of the carrier. Figure 49 plainly .illustrates one ofthe pawls 36 within the notch 3 7 vso as to po'si- .13

tively prevent the rearward movement of the rack 2O and the premature collapse of the bit as the result of excessive pressure thereon.

However, when it is desired to collapse the bits, for removal of the drill the controlling bar 19 is drawn upwardly by means to be later described and the lug 31 will be moved out of the way of the dog 32 while the projections 24- will be moved out of locking engagement with the pawls 36. Now as the controlling bar 19 moves upwardly the upper ends of the projections 24 will be engaged with the cross bars 22 so as to retract the rack. The upward movement of the rack will cause the lug 33 to engage the shoulder 34 on the dog-32 and consequently return the dog to its original position as il- -lustrated in Figure 7 so that the controlling bar connot descend. i

It will be noted that when the parts are in their lowering osition as illustrated in Figure 7 the welg t of the controlling bar and the members mounted thereon is transmitted to the carrier through the lug 31 the dog 32 and the cross member 27 which is rigidly connected to the carrier.

The improved drill is lowered through a drill stem 40, the lower end of 'which is provided with a drill stemcollar 41 having oppositely arranged cavities or slots 42 for the passage ofV the bits and bit holders. The drawings illustrate that the collar 41 is greater in internal diameter than the internal diameter of the drill stem and consequently when the bits enter the collar 41 they may expand slightly which will result in the ownward movement of` the racks. Figure 3 illustrates that the interior of the collar 41 is provided with oppositely arranged grooves 43 which gradually decrease in width toward their lower ends so as to guide the bit holders into the slots. rlhe lThe rooves 43 not only serve as a means for guiding the bit holders into the slots 42 but also as a very effective means for causing the notches 44 on the lower end of the carrier to receivesupporting lugs or pins 45 extending inwardly from opposite sides of the collar 40. This prevents the bit trom moving out of the lower end o the collar or drill stemduring the drilling operation.

' Attention is directed to the fact that that portion of the collar directly behind each bit holder is formed with an extension which effectively braces the bit holder and reduces mounted thereon, the said sectional weights bemg designated by the numerals 50 and 51. In carrying out the invention the sectional weights 50 and 51 are mounted for sliding.

movement on the controlling bar and the weights ma move upwardly but not downwardly with relation to the controlling bar. Figure 23 illustrates that the controlling bar is formed with an annular shoulder 53 which contacts with an internal shoulder 54 on the sectional weight 50 and below a collar 53 on the controlling bar which engages shoulder 54 and thereby prevents the sectional weights from moving downwardly with relation to the controlling bar. Sectional weight 51 is similarly .held against downward movement relative to the controlling bar by a collar 51il on said bar similar to collar 53a. However, when the dog 32 is moved to the position illustrated in Figure 9 the mandrel or controlling bar will descend and the sectional weights will also descend for engagement with the rack and thereby force the bits to their operative positions.

Figure 14 illustrates that the upper portion of the controlling bar 19 is connected through the medium of a .rivet 55 with a pair ofears 151 to which the Shanks 153 of gr1ppmg.]aws 54 are pivoted. as indicated.

Jaws 54 have their opposed sides formed with recesses for the reception of the fiattened and flared forward end 57 of a lowermg member 58. The shanks 153 are urged outwardly by means of coiled springs 59 confined between the shanks and a tubular extension 6() depending from the head 51.

The inwardly extending terminal portions .61 of the Shanks 153 may be positivelv held 1n the position illustrated in Figure 1,3 by means of the annular rib 63 formed on the upper end of a sliding collar 64. The annular rib 63 forms one side of an annular groove 65 which is adapted to receive the inwardly extending terminal portions 61 of the Shanks 153. Then the inwardly extending terminal portions 61 are received within or are arranged opposite the annular groove 65 lthe connection between the jaws 54 and the lowering member 58 may be broken so as to release the lowering mechanism for withdrawal tothe surface.

The'collar or head 64 is provided with a pair of depending stems or actuating rods 68 which are receivedin oppositely arranged grooves in opposite sides of the upper sectional weight 51 and as illustrated in Figure 15 the depending stems 68 terminate slightly in advance ot the upper weight 51 for engagement with the upper end of the lower weight 50.

Vhenthe controlling member 19 descends to the position illustrated in Figure 9 as a result of its release, the sectional weights also descend and as the foremost sectional weight 50 is limited in its descent by eu- 68 whereupon the annular groove 6 5 will be positioned between the inwardly extending terminal portions 61 of the Shanks 153.

A slight pull on the cable or lowering member 58 will result in the disconnection of the same from the jaws 54.

The drill in its descent through the drill stem encounters extremely heavy lnud and the pressure of this mud on the sectional weight is prevented from moving the weight upwardly by means of a spring locking arm 80, the terminal portion of which is formed with a hook received in a longitudinally extending socket or recess 81 in the lower end of the lower weight 50. lVith reference to Figure 7 it' will he observed that the hooked end portion of the arm will positively prevent the lower sectional weight from prematurely actuating the depending stems 68 and the head 64.

In operation thejdrill is stood upright on the derrick floor and the head or collar 6ft is moved to the position illustrated in Figure 8 so that the inwardly directed terminal portions 61 of the Shanks 153 may move inwardly. This permit-s the lowering rod 58 to be positioned between and to be engaged by the jaws 54. Now the shanks 153 are released'by the lingers of the operator so that the springs 59 will move the same to the position illustrated in Figure 13. Subuent to this the member 64 is lowered so that'the rib 63 will be positioned between the inwardly directed terminal portions of the shanks 61 for positively holding the jaws in engagement with the lowering mechanism.

The bits being collapsed, the drill is introduced into the drill stem and the weight ofthe rack will cause the bits to move to the position. illustrated in Figure 7 and contact with the interior of the drill stem. lVhen the bits or cutters reach the enlarged collar 41 at the lower end of the drill stem they will move outwardly under the weight of the racks 20 and consequently the projections 30 will en age the rounded upper end of the dog 32. imultaneously with the advance of the projections 30 the holding member 33 will be released from engagement with the shoulder 34 and `the dog 4is thereupon swung to theriglit or to the position illustrated in Figure 9. This allows the mandrel and the weights carried thereby to descend. e

.lVhen thc mandrel or controlling bar 1%) and sectional weights thus descend the rcduced lower end 18 ofthe mandrel will be received within the grooves 16 and 17 so as to positively lock the bits in their extended positions. As previously stated the descent of the mandrel will force the locking'pawls 3.6 to partake of a swinging movement.

whereupon the same are received within the openings 37 for locking the racks to the carrier and preventing the collapse of the cutters as the result of side or end pressure thereon.

When the controlling bar descends the sectional weight 50 will contact with the racks andof course move the cutters to their fully extended positions.

lVhen the parts of the drill move to their operative positions illustrated in Figure 9.

"viscd of the fact that the drill is in its fully extended position and all the locks are set. The drill stem mayv now be. operated for continuation of drilling. i

lVhen it is desired to withdraw the drill for the purpose of renewing or sharpening the bits a raising device or lifting tongs is sentdown through the drill stem which engages with the cone-shaped head formed by the jaws 54 and the tongs 90 are subsequently moved upwardly so as to exert an upward pull on the controlling bar 19.

When an upward pull is exerted on the controlling bar 19 the sectional weights are drawn upwardly and the u per ends of the projections 24 are engage with the cross bars 22 so as to move the racks upwardly and j thereby collapse the bits. The extent of collapse of the bits is controlled by the length ot the slot 25 and the engagement of the pin 26 with the lower end of the slot. When 30 and 33 also move to the positions illustrated in Figure 7 lVith the parts thus positioned the weight of the controlling bar and sectional weights is removed from the racks but the racks still have a tendency to descendof their own weight and thus preserve the tendency ofthe cutters to expand whenever they enter the larger diameter ofthe collar at bottom of drill stem. The racks always press on the bit holders and tend to expand them which is a very' im# portant part of the invention.

- As the welldeepens, the `mud within the drill stem is compressed near the bottom and becomes more dense and decreases the speed with which the drill descends. The provision of the sectional weights successfully counteracts the density of the mud and causes the drill to move promptly to the lowr end of the vdrill stem and fully exp As the drill stem is sometimes curved, I have provided a plurality of universal joints 89 of any desired construction in the controlling bar so that the drill may adjust itself to the bends in the stern.

Any desired number ofweights and universal joints may be employed.

In carrying out the invention the upper sectional weight 51 is provided with a plurality of longitudinally extending guide ribs S93-which center the drill in the stem andxthereby facilitate the engagement of the raising tongs with the cone-shaped head.

As illustrated in Figure 12 the forward end of the bit carrier is provided with beveled faces 103 which cooperate with the beveled portions 104 of the bit holders in the formation of orifices thru which the mud pumped down thru the stem passes. 'The orifices thus formed when the bit holders are expanded are so shaped that the mud as it is pumped down thru the drill stem is directed by'each orifice along the front of the opposite collar holder and thus keep the cutter holders and cutters clean so that they will drill better and also permit them to collapse easily where it is desired to withdraw the bit. In other words, each recess 104 forms with the adjacent bevelled portion 103, a groove which simply guides the pumped mud across the front face 0i the opposite cutter holder.

More specifically one side of each cutter is beveled as indicated at 104 and the adjacent side of the carrier is beveled as indicated at 103 so as to define a pocket through which the mud Hows on its way to the bit. Of course there are two such passages because each bit holder is provided with a beveled portion 104 and there are a corresponding number of beveled portions 103.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same and that such minor changes in arrangement and construction of parts may be made as will remain within the spirit of the invention and the scope of what is claimed.

Having thus described the invention, what I claim is K 1. A n improved deep well expansive and contractive drill comprising a carrier, cutters pivoted thereto, racks for operating said cutters and a controlling bar movable through said carrier, said bar being normally supported by said racks and having means movable into engagement with the cutters to lock the latter in operative position.

Q. An improved expansive and contractive deep wel] drill comprising a carrier, cutters pivoted thereto, racks for operating said cutters and movable through said carrier, a

controlling bar having means to lock the cutters in operative position, and a locking pawl pivoted to one ofv said racks and adapted for locking engagement with-said carrier, whereby to hold the racks in a set position.

3. An improved expansive and contractive deep well drill comprising a carrier, cutters pivoted thereto, racks for operating said cutters, a controlling bar movable through said carrier and having means to lock the cutters in operative positions, lockin pawls pivoted to said racks and adapted or locking engagement with said carrier, and means slidable on said controlling bar for advancing said racks and moving said cutters outwardly.

4. An improved expansive and contractive deep 'well drill comprising a carrier, cutters pivoted thereto, racks havin connection with said cutters, a controlling ar movable through said carrier and havin a shoulder, a cross bar connected to sai racks and arranged in the path of travel of said shoulder, and locking pawls pivoted to said racks and arranged in the path of travel ot said shoulder and operated thereby, said locking pawls being adapted for locking engagement with the carrier.

5. An improved expansive and contractive deep well drill comprisin a carrier, cutters pivoted thereto, racks geving connection with said cutters, a controlling bar movable.

through said carrier and having a shoulder, a cross bar connected to said racks and arranged in the path of travel of said shoulder, locking pawls pivoted to said racks and arranged in the path of travel of said shoulders and operated thereby, a holding dog pivotally supported by said carrier, and a ug carried by said controlling bar and engaged with said dog whereby the weight of said controlling bar is transmitted directly to said carrier.

6. An improved expansive and contractive deep well drill comprising a carrier, cutters pivoted thereto, racks having connection with said cutters, a controlling bar movable through said carrier and having a shoulder, a cross bar connected t0 saidracks and arranged in the path of travel of said shoulder, locking pawls ivoted to said racks and arranged in the pat of travel 0f said shoulders and operated thereby, said locking pawls being adapted for lookin engagement with the carrier, a holding og pivotally su ported by said carrier, a lug carried by sai controlling bar and engaged with said dog whereby the weight oV said controlling bar is transmittedv directly to said carrier, and an o rating lug rigidly connected to said rac and `adapted to engage` said dog to move the same from beneath said first named lug. i

7. A11 im roved expansive and contractive deep well rill comprising a carrier, cutters pivoted thereto, racks having connection with said cutters, a controlling barl movable through said carrier and having a shoulder, a cross bar connected to said racks and arranged in the path of travel of said shoulder,

lockin pawls pivoted to said racks andarrange in the path of travel of said shoulders and operated thereby, a holding dog pivotally supported by said carrier, a lug carried by said controlling bar and enaged with said dog, an operatln lug rigi y connected to said rack and a apted to enga e said dog to move the same from beneati said first namedelug, and a combined holding and return lug connected to the racks and engadged with the intermediate portion -of said og 8. im roved expansive and contractive deep well rill comprising a carrier, cutters pivoted thereto, racks having connection with said cutters, a controlling bar having a shoulder, a cross bar connected to said racks and arranged-in the ath of travel of said shoulder, locking paw s pivoted to said racks and arranged in the path of travel of said shoulder and operated thereby, a holding dog pivotally sup orted b said carrier, a lug carried by said contro ing bar engagedwith said dog whereby the weightof said controlling bar is transmitted directly to said carrier, an o erating lug rigidly connected to said rac and adapted to engage said dog to move the same from beneath said first named lug, and a pin pivotally connecting said dog to said carrier, said controlling bar being rovided with a slot slidably receiving sai pin, said slot and said pin constitutin a means to limit the sliding movement of t e controlling bar with relation to the racks and also to limit the upward movement of the racks with relation to the said carrier so that the tendency of the cutters to ex and by weight of the racks will atall times e preserved.

9. Animproved expansive and contractive deep well drill. comprising a carrier, `bits pivoted thereto, links pivoted to said bits, racks pivoted to said links, a controlling bar having its lower end provided with a locking member, said links and said cutters being provided with registering grooves adapted to y*receive said locking member.

10. An improved expansive and contractive deep Well drill comprising a carrier, bits pivotally associated therewith, links connected to said bits and having their opposed sides formed with grooves adapted to be positioned directly opposite each other, and

a controlling bar adapted t5 enter. said op- Y tive deep wel positely located grooves to lock the and the bits connected thereto against accidental collapsing. f 4

11. An improved expansive and contracdrill comprising a carrier, bitsl pivotally associated therewith, links connected to said bits and having their opposed sides formed with grooves ada ted to be positioned directl op 'te eac other, a controlling bar a apte to enter said oppositel located grooves to lock the links and the its connected thereto lagainst accidental collapsing, and racks movable longitudinally of said carrier and havin -connection with said links for controlling t e same.

12. An improved expansive and contractive dee well bit comprising a plurality of cutters aviiig their o posed sides formed with grooves, a control ing memberl adapted to be received in said grooves whereby to hold the cutters in a set osition against the pressure thereon, and links connected to said cut-ters'and havinggrooves re 'sterin with said first named grooves and a apted or the reception of said'controlling member whereby the links are held in a set position.

13. An improved expansive and contractive deep well bit comprising a plurality of cutters having their opposed sides formed with grooves, a controlling member adapted to be received in said grooves whereby to hold the cutters in a set position against the pressure thereon, links connected tol said cutters and having grooves re terin with said first named grooves and a apted for the reception of said controlling member whereby the links are held in a set position, and racks connected to said links and having connection with said controlling member.

14. An improved expansive and contractive deep well bit comprising a carrier, cutters pivotally associated with said carrier, links pivoted to said cutters, racks connected to saidlinks, and a controlling bar movable between said racks and having means to engage said links and said cutters for holding the same in a set position against the pressure on the cutters.

l5. An improved expansive and contractive deep well drill comprising a carrier, cutters Vassociated therewith, racks connected with said cutters for expanding and contracting said cutters, a controlling bar movable through said carrier between and in movable' connection with the racks and having means to hold the cutters in expanded position, there being a pin and slot connection between the contrlling bar andthe carrier whereby to limit the movement of the controlling bar with relationto the carrier, and also to limit the upward movement of the racks with relation to the' carrier and thus preserve the tendency of the cutters to at all times expand.

16. An improved expansive and contractive deep well drill comprising cutters, racks to which said cutters are pivotally connected for expanding and contracting the cutters, a controlling bar arranged between said racks and normally controlling movement thereof, and a plurality of weights mounted on said controlling bar and adapted for actuating said racks.

17. An improved expansive and contractive deep well drill comprising cutters, racks to which said cutters are pivotally connected for expanding and contracting the cutters, a controlling bar associated with said racks, a plurality of weights mounted on said controlling bar and adapted for actuating said racks, said controlling bar being provided with means holding the weights against downward movement on the controlling bar.

18. An improved expansive and contractive deep well drill comprising a controlling bar, cutters, means controlled by said bar for expanding and contracting the cutters, weights slidable on said bar, a gripping device carried by said bar, and a head on the bar having means operated by said weights for controlling said gripping device. l

19. An improved expansive and contractive deep well drill comprising a controlling bar, gripping jaws carried thereby. a head movable on said controlling bar and having means to hold said jaws in engagement with a lowering mechanism, and weights movable on and normally controlled by said bar for shitting said head whereby to release the jaws.

20. An improved expansive and contractive deep well drill comprising cutters, racks associated with the cutters, a controlling bar associated with the racks and extending a substantial distance upwardly from the racks, weights mounted on said controlling bar and adapted for forcing down said racks, gripping jaws associated with said .controlling bar and having means for gripping a. lowering mechanism, said jaws being provided with depending Shanks, a head mounted on said controlling bar and having a groove to receive said shanks, a depending stem carried by said head and engaged by one of said weights, whereby to actuate said head.

21. An im roved expansive and contractive deep well) drill comprising cutters, racks supporting and controlling the cutters, a controlling bar connected with and controlling the racks, a gripping mechanism carried by said controlling bar and having depending shanks, a head mounted on said controlling bar and provided with means engaging said Shanks whereby to hold the gripping mechanism in position, said head being provided with means to receive the shanks whereby to permit the gripping mechanism to move to its inoperative position, spring means urging said gripping ling bar and adapted for actuating said` racks, locking arms carried by a cross member at top of said racks and adapted to engage one ot said weights whereby to limit the sliding movement of the same on said controlling bar, and agripping mechanism associated with said controlling bar and operated by said weights. j

23. An improved expansive and contractive deep well drill comprising a carrier, bits associated therewith, racks associated with the bits, a controlling bar adapted for engaging said bits to hold Lthe same in position, Vweights mounted on -said controlling bar, means to limit the sliding movement of one of the weights with relation to the controlling bar, a head having a pair of depending stems slidable through one of said weights and engaged by the other weight, a pair of jaws pivotally7 associated with the controlling bar and having depending Shanks provided with inwardly directed ter-- minal portions, said head being provided with an annular rib engaged with the inwardly directed terminal portion whereby to hold the jaws in their operative positions, said head also being provided with an annular groove to receive the inwardly directed terminal portions of said Shanks, and spring means engaged with said Shanks to urge the jaws to their operative positions.

24. An improved expansive and contractive deep well drill comprising a carrier, bits pivotally supported in connection therewith, links pivoted to said bits, racks movable with respect to the carrier and pivoted to said links. a controlling bar having its lower end provided with a locking member, said cutters being provided with registering grooves adapted to receive said locking members.

25. An improved expansive and contractive deep well drill comprising a plurality of cutters having their opposed sides formed with grooves, a controlling member adapted to be received in said grooves whereby to hold the cutters in a set position, links connected to said cutters. and racks connected to said links and having sliding connection with said controlling member, there being means to limit the sliding movement of the controlling member-with relation to said racks.

26. An `improved expansive and contractive deep well drill comprising a `carrier, cutters pivotally associated with said carrier, links pivoted to said cutters, racks eonling bar associated with the racks, a section- 10 nected to said links and a controlling bar al Weight mounted onsaid controlling bar movable between said racks and having and adapted to actuate said racks, hooked means to engage said cutters for holding the locking arms carried by said racks and same in a set position against the pressure adapted to engage said weight to limit slid- Y in use on the cutters. ing movement of the latter, and a ipping l5 27. An improved expansive and contracmember associated with said contro ing bar tive deep Well drill comprising cutters, and controlled by said weight. racks associated with the cutters` a control- OSCAR MARTIN CARTER.

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