US3797589A

US3797589A - Self guiding force applicator

Info

Publication number: US3797589A
Application number: US00351628A
Authority: US
Inventors: J Kellner; G Alther
Original assignee: Smith International Inc
Current assignee: Smith International Inc
Priority date: 1973-04-16
Filing date: 1973-04-16
Publication date: 1974-03-19
Anticipated expiration: 1991-03-19

Abstract

A self guiding force applicator includes a tubular mandrel to deliver fluid to drilling means. A piston carried by the mandrel moves in a cylinder to which fluid is supplied to force mandrel or cylinder in or out. The mandrel and cylinder are connected by spline means to prevent relative rotation while allowing relative axial motion. Releasable anchor means anchors either cylinder or mandrel to wall of bore hole dependent upon whether mandrel or cylinder is to be moved. The mandrel anchor means is disposed at the outer end of the force applicator to serve as a guide means when in the released position during drilling. Also at the outer end of the mandrel is a manifold for connecting conduits and passages in the mandrel to an outer end of the force applicator. The hose line is wound on an out-of-hole winch mounted on a trailer cart. Launching means for the force applicator and drilling means, together with supply and control means for the anchor means, piston and cylinder means, and the drilling means, is also mounted on the car.

Description

United States Patent Kellner et al.

[ 1 SELF GUIDING FORCE APPLICATOR [75] Inventors: Jackson M. Kellner; George Abraitys Alther, both of Midland, Tex.

[73] Assigneei Smith International, Inc., Midland,

Mich.

221 Filed: Apr. 16, 1973 21 Appl. No.2 351,628

Related US. Application Data [63] Continuation of Ser. No. 189,845, Oct. 18, 1971,

abandoned.

[52] US. Cl 175/94, 175/99, 175/203, 175/230 [51] Int. Cl. E21b 3/12, E2lb 19/08, E210 9/00 [58] Field of Search 175/94, 97, 99, 98, 230, 175/203, 122, 62, 220, 53; 51/727; 299/31; 254/1346 [56] References Cited UNITED STATES PATENTS 556,718 3/1896 Semmer 175/94 2,500,785 3/1950 Arutunoff 175/203 X 2,712,920 7/1955 Cullen et a1. 175/99 2.946.578 7/1960 De Smaele 175/62 X 3,180,437 4/1965 Kellner et al. 175/230 3.354.969 11/1967 Ebeling.....- 175/94 Mar. 19, 1974 3,376,942 4/1968 Van Winkle 175/99 X 3,399,738 9/1968 l-laspert 175/53 3,604,754 9/1971 Kampf-Emden et al. 299/31 X 3,643,999 2/l972 Kampf-Emden et a1 299/31 Primary ExaminerDavid H. Brown cylinder or mandrel to wall of bore hole dependent upon whether mandrel or cylinder is to be moved. The

' mandrel anchor means is disposed at the outer end of the force applicator to serve as a guide means when in the released position during drilling. Also atthe outer end of the mandrelis a manifold for connectingconduits and passages in the mandrel to an outer end of the force applicator. The hose line is wound on an out-of-hole winch mounted on a trailer cart. Launch- ,ing means for the force applicator and drilling means,

together with supply and control means for the anchor means, piston and cylinder means, and the drilling means, is also mounted on the car.

18 Claims, 20 Drawing Figures PATENTEDMAR 19 I974 SHEET 1 U 7 s A Q/fibli a R \W a PATENTEUHAR 19 mm 87971589 sum u 0F 7 I NM If %WW I SELF GUIDING FORCE APPLICATOR CROSS REFERENCE TO RELATED APPLICATION This application is a continuation of prior copending application Ser. No. 189,845, filed Oct. 18, 1971, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to earth boring and more particularly to a force applicator for axially loading a drill bit, especially an in-hole motor driven drill bit used in boring horizontal vent holes in mining for coal.

2. Description of the Prior Art Coal bed vent holes have been drilled with auger bits. After the hole exceeds several hundred feet in length difficulty is experienced in maintaining directional control. The use of an in-hole drilling machine has been suggested to eliminate the need for transmitting torque the length of the drill stem. However, it was still necessary to use the drill stem to transmit axial forces to load the bit. In drilling oil wells it is known to provide inhole bit loading means, as shown for example in U.S. Pat. Nos. 3,088,532 issued May 7, 1963 on the application of J. M. Kellner and 3,298,449 issued Jan. 17, 1967 on the application of W. R. Bachman et al. Automatic valve means for such apparatus is shown in U.S. Pat. No. 3,105,561 issued Oct. 1, 1963 on the application of J. M. Kellner.

In the application of said Jackson M. Kellner filed contemporaneously herewith, Ser. No. 189,844, filed Oct. 18, 1971, now abandoned, and the copending continuation thereof application Ser. No. 351,629 filed Apr. 16, both entitled FORCE APPLICATOR, an inhole force applicator is disclosed in combination with an in-hole motor driven bit for effecting better direction control in the drilling of horizontal earth bores. The tubular mandrel for supplying fluid to the in-hole motor driven bit is provided with a piston connected to the mandrel which moves in a cylinder that is connected to the mandrel by spline means. Fluid is applied to the cylinder to move the piston or cylinder in or out as desired. Releasable anchor means are connected to the cylinder and mandrel to anchor one or the other to the bore wall when the other or one is to be forced in or out. The mandrel anchor means is disposed between the in-hole motor driven bit and the piston and cylinder means. A guide means in the form of a centralizer or stabilizer is connected to the mandrel axially outward from the piston and cylinder means.

According to one form of the apparatus disclosed in said contemporaneous Kellner application a plurality of flexible fluid conduits supply fluid to the two sides of the piston and cylinder means and to the two releasable anchor means and to the in-hole motor driven bit. The guide means body serves also as a manifold for connecting the flexible conduits to the fluid conduits of the force applicator. The plurality of conduits extend out to the open end of the bore hole where they are wound on motor driven reels or winches. Out-of-hole hydraulic control means is provided for manually or automatically supplying fluid to the desired in-hole means for effecting inward or outward travel of the mandrel or cylinder.

SUMMARY OF THE INVENTION The present invention is upon improvement upn the prior conceived invention disclosed in the aforesaid contemporaneous application of Jackson M. Kellner.

According to the present invention there is provided a force applicator similar to that of the above described Kellner force applicator but wherein the mandrel anchor is disposed axially outward of the piston and cylinder means where, when in the unset, i.e. disengaged or retracted, condition it will function as a guide means, thereby eliminating the need for separate guide means at this position along the mandrel and shortening the overall length of the apparatus for any given stroke. In addition, such positioning of the mandrel anchor means makes it unnecessary to transmit fluid for such anchor means through the rest of the force applicator. This also simplifies the. construction of the hose connection manifold which serves also as means to connect the mandrel to the barrel of the mandrel anchor means. Further in accordance with the invention the flexible conduits supplying fluid to the force applicator may be bondedinto a single multiple fluid passage flexible conduit. Improved reeling means and hydraulic control means are provided.

BRIEF DESCRIPTION OF THE DRAWINGS For a detailed description of .a preferred embodiment of the invention and modifications thereof reference will now be made to the accompanying drawings (FIGS. 3 thru 16 are substantially full size and to scale for an exemplary tool) wherein:

FIG. 1 is a semi-schematic view' showing a vertical section through a horizontal earth bore with apparatus according to the invention disposed therein shown in elevation and in section;

FIG. 2 is a schematic view illustrating an inhole rotary drilling machine with which the subject invention may be used; 1

FIGS. 3, 4, 7, I0 and 11 together form an axial section through a force applicator according to a preferred embodiment of the invention;

FIGS. 5, 6, 8, 9, 12, 113, 14, 15, 16 are transverse sections taken through the force applicator shown in the preceding drawings, such sections being taken on the planes indicated in said preceding drawings;

FIG. 17 is a perspective view showing out-of-hole apparatus used in conjunction with the in-hole apparatus shown in the preceding drawings, said in-hole apparatus also being shown being launched into the hole;

FIG. 17A is a sectional view through the hose 87; and

.FIGS. 18 and 119 are schematic views showing hydraulic systems useful in the out-of-hole apparatus.

As is apparent from the sectioning of the drawings, all parts are made of steel unless otherwise indicated or stated.

DESCRIPTION OF THE PREFERRED EMBODIMENT In this patent specification, unless the context indicates otherwise, the term inward is used to denote the axial direction toward the closed end of the bore hole and the term outward is used to denote the axial direction away from the closed end of the hole.

Since this application discloses improvements on the construction disclosed in the aforesaid contemporaneous application of Jackson M. Kellner, the disclosure thereof is incorporated herein by reference for the disclosure and description of various details of the present construction which are the same as those of the construction disclosed in said contemporaneous Kellner application thereby avoiding repetition.

Referring now to FIG. 1, there is shown an earth bore 51. The term earth is here and in the claims used in a broad sense to cover all materials of which the planet Earth is formed; it will be understood that frequently the earth will be coal. At the inner end of the earth bore is a drill bit 53 connected to the rotary drilling machine 57. The non-rotating part 59 of the drilling machine is connected to mandrel sub 61. The sub 61 is in turn connected to mandrel 63 of force applicator 64.

The mandrel, which is made up of a number of tubular sections, includes a spline section 65 which carries an externally fluted sleeve 67. Sleeve 67 travels axially applicator is used to apply force to the drilling machine 57. The anchor means in turn is connected to cylinder 77. The mandrel 63 continues on from the spline section 65 thereof through cylinder anchor means 73 into cylinder 77 where its piston rod section 79 is provided with a piston 81. Piston 81 reciprocates in cylinder 77 and together the piston and cylinder form piston and cylinder means 83. I

The piston rod section of the mandrel extends outwardly beyond cylinder 77 and connects to mandrel anchor and guide means 85. The anchor and guide means in turn connects to flexible hose line 87 which extends out the open or outer end of the earth bore. A guide funnel 91 is disposed in the open end of the earth bore.

The hose line 87 is either a bundle of five separate hoses or is a single hose that includes five fluid passageways. The hose line 87 connects intoa manifold provided by the body of anchor and guide means 85. The fluid from hose 87 is used to supply pressure fluid to the two anchor means and the two sides of the piston and cylinder means and to the rotary drilling machine,

being conducted via the manifold and the mandrel and known as a Dyna-Drill. Apparatus of this type is shown in various publications. See US. Pat. Nos. 2,898,087 and 3,112,801, and Dyna-drill Handbook published I970 by Dynadrill Div. of Smith Autl., Inc. Such a rtary drilling machine is shown schematically in FIG. 2, which is based on the illustration at the right on page 1,870 of the l970-7l edition of the Composite Catalogue of Oil Field Equipment and Service. As there described, the drilling machine 57 includes a motor 101 which is essentially a three-stage Moyno Pump run in reverse and comprising about one-half of the total 25 foot length of the tool. The motor consists of an obround-shaped spiral passage 103 containing a solid steel rotor 105 which moves eccentrically. Shaped in a regular-recurring wave form, this rotor is free to move at the outer end 107, while the inner end 109 is attached to one end of a connecting rod 111. The other end of the connecting rod is attached to tubular drive shaft 113.

Thrust bearings

115, 117 on the drive shaft prevent it from moving axially inside housing extension 119. When water is pumped under pressure into housing connection 121 at the outer end of the tool, the pressure closes spring loaded slide dump valve 123, closing port 125. The water is thus directed down the annulus 127 between the rotor 105 and the rubber lined spiral passageway 103. In order for flow to occur, the rotor is displaced and turned by the pressure of the fluid column, thus rotating the connecting rod l11,the tubular drive shaft 113 and the bit sub 129. The latter is connected to the inner end of the drive shaft where it extends out beyond housing extension 119. The water, or other fluid, leaves the annulus 127 by entering port-131 in the tubular drive shaft. The water then passes through the drive shaft, bit sub, and diamond bit 53, and leaves bit 53 via passages 133, where it enters the bore hole. The water leaving the drill bit passes back to, the open end of the hole outside the drilling machine, the force applicator, and the hose connected thereto, carrying away the detritus and cooling the bit. It will be seen that although the drive shaft 113 rotates relative to the tool housing 135, inward force applied axially to the housing through connection 121 is trans ferred to the drive shaft 1 13 through the thrust bearings 117 and thence to the bit 53. Likewise, .outwardly directed force applied to housing 135 is transferred to the drive shaft through thrust bearing and thence to the bit.

Referring now to FIGS. 3 et seq., there are shown the details of a force applicator embodying the invention. Beginning with FIGS. 36 there is shown in detail the spline means 71 and cylinder-anchor means 73 shown schematically in FIG. 1. At the right hand side of FIG.

3 is shown the sub 61 (see also FIG. 1) for making con nection with the drilling machine 57. The sub 61 is screwed onto pin 516. Pin 516 is'welded on to the inner of a pipe 518. The outer end of pipe 518 is welded to threaded box 520 (FIG. 4). Together, the pin 516, tube 518, and box 520 form the spline section 65 (FIG. 1) of the mandrel of the force applicator.

Externally fluted sleeve 67 is pressed or shrunk onto pipe 518. Disposed around spline section 65 of the mandrel is tube 69, which, as best shown in FIG. 5, is internally fluted correlative to fluted sleeve 67. There is thus provided spline means 71 which allows relative axial motion of the mandrel and tube while preventing relative motion therebetween. The flutes on the sleeve 67 leave axially extending ribs 519 therebetween which fit between the ribs 521 of fluted tube 69. The ribs 519 are provided at their outer peripheries with channels 523 to permit solid materials to be flushed more easily out of the spline means 71. I

To the inner end of tube-69 (FIG. 3) is screwed a coupling 522 which in turn is screwed to guard cup 526. The guard cup 524 and sub 61 cooperate to provide stop means limiting relative axial travel of the mandrel and tube, end 525 of the guard cup being engageable with end 62 of sub 61.

Within coupling 522 is pressed or shrink fitted a seal ring 526 having an annular rubber seal 528 bonded to the inner periphery thereof. The spline section 65 of the mandrel of the force applicator extends axially through seal ring 562 in sealing engagement with seal 528.

As shown in FIG. 4, the box 520 is screwed onto pin 530 which forms the inner end of the piston rod section 79 (see also FIG. 1) of the mandrel of the force applicator. Section 79 further includes pipe 532 to which pin 530 is welded. Pipe 532 extends axially slidably through and in sealing engagement within annular rubber seal S34 bonded to the interior of the combined barrel head and cylinder-head formed by seal ring 536. The latter is press or shrink fitted inside coupling 538.

A barrel 540 is screwed at one'end to coupling 538 and at the other end to spline tube 69. There is thus formed a chamber 543 between the mandrel and the barrel and spline tube, the chember being sealed at its ends by

seals

534 and 528 of seal rings or barrel heads 536 and 526. Pressure fluid may be conducted into and out of the chamber 543 through mandrel port 541, the latter being connected to conduit 546 which extends outwardly to the outer end of the force applicator where it connects to a pressure fluid conducting hose (see infra).

Referring now particularly to FIGS. 5 and 6, the barrel 540 is provided with a plurality of windows 542 spaced equally apart around the circumference thereof. Disposed in each window for radial in and out movement is a bore wall engageable shoe 544. Each shoe is provided with a plurality of teeth 545 or other means for preventing axial and circumferential slippage of the shoe when engaged with a bore wall.

Each shoe is sealed to its window byan elastomer (rubber) seal 548, bonded to the window and to the sides and inner periphery of the shoe, the seals 548 merging to form a continuous sleeve around the tube 532. The seals normally hold the shoes as shown in the unset or retracted position and have sufficient resilience to allow the shoe to be projected radially outwardly into bore wall engaging or set position when fluid pressure in chamber 544 exceeds that outside the force applicator. Upon equalization of such pressures, the resistence of the seals retracts the shoes to the disengaged or retracted position shown.

The sides 549 of the barrel 540 are flattened to provide fluid passage means between the barrel and the wall of the earth bore in which the apparatus is used. Further details of the operation of such wall anchor means are set forth in the aforementioned Kellner and Bachman et al. patents.

Referring now to FIGS. 7-9 there are shown the details of the piston and cylinder means 83 shown schematically in FIG. 1. Cylinder 77 is screw connected at 550 to coupling 538, by which means it is connected to barrel 540 and spline tube 69 (FIG. 4). The outer end of cylinder 77 is connected by threaded coupling 552 to guard cup 554.

Reverting for a moment back to FIG. 3, as previously mentioned the outer end 525 of guard cup 524 cooperates with the inner end 62 of sub 61 to provide stop means limiting relative axial travel of the mandrel and spline tube 69. Since the spline tube is connected to anchor barrel 540, this stop means also limits relative axial travel of the mandrel and the anchor barrel in one direction. Relative axial travel of the mandrel and the anchor barrel 540 in the opposite direction is limited by stop means comprising guard cup 554 and barrel head 556 (FIG. 10) of the mandrel anchor and guide means 85. The end 558 of the guard cup 554 engages end 560 of barrel head 556 to limit such motion. Within the limits of relative axial motion of the mandrel and cylinder anchor barrel just described, mandrel port 541 (FIG. 4) is always in communication with chamber 543.

Referring once more to the piston and cylinder means 83 shown-in FIGS. 7-9, pipe 532 of the piston rod section 79 of the mandrel of the force applicator extends axially through cylinder 77 and is axially slidably sealed thereto by seals S34 and 562, respectively bonded to seal

rings

536 and 564. The latter are press or shrink fitted in

couplings

538 and 552 and together with the seals carried thereby provide cylinder heads. In the space between the cylinder heads travels piston 81 which is secured to pipe 532 Part of the drawing'is broken off between

cylinder heads

536 and 564; the length of cylinder 77 and pipe 532 actually will be about the same as the length of the spline tube and the mandrel section therewithin, and the same as the length of the cylinder anchor barrel and the mandrel section therewithin, so as to provide equalstroke for the spline means and the cylinder anchor means and the piston and cylinder means. The stop means previously described which limit relative axial travel of the mandrel and cylinder anchor barrel'also prevent the piston from contacting the cylinder heads and prevents the spline sleeve 67 from striking the barrel 540 (FIG. 4) and the barrel head 526 (FIG. 3).

Piston 81 comprises annular body 566 which is secured to the tube 532 by collet clamp 568, the latter being activated by compression ring 570. Ring 570 is screwed into body 566. Ring 566 is sealed to tube 532 by rubber O-bo'dy 572. The exterior of piston body 566 is bonded to rubber seal 574. This-construction is described in greater detail in the aforementioned contemporaneous Kellner application to which reference may be made if need be.

Pressure fluid conduits

605, 607 are connected to mandrel

ports

609, 611 whereby pressure fluid can be supplied to and released from the

spaces

613, 615 at the inner and outer ends of the piston and cylinder means on the opposite sides of the piston. The ends 617', 619 of the piston body 566 and ring 570 are spaced radially outwardly from the mandrel so that

ports

609, 611 can be placed thereunder without being blocked; this allows the ports to be placed that much closer together, to increase the effective stroke of the piston and cylinder means.

Wrench sockets

618, 620 are provided in the

ends

617, 619 to facilitate screwing ring 570 into body 566.

Pipe 532 of the piston rod section of the mandrel extends outwardly from guard cup 554 to the hose connection, mandrel anchor and guide means 85 shown in detail in FIGS. 10-16.

Referring particularly to FIG. 10, pipe 532 is welded at its outer end to manifold 630. Mandrel anchor barrel 632 is screwed at its outer end to manifold 630 in fluid tight'relationship and is screwed at its inner end to barrel head 556, also in fluid tight relationship. Head 556 is sealed to pipe 532 by rubber O-ring 634. There is thereby defined between barrel 632, pipe 532, seal 634, and manifold 630 a chamber 636.

There are a plurality of windows 638 in barrel 632 equally spaced apart circumferentially around the barrel. Within each window is disposed a bore wall engageable shoe 640. Each shoe is sealed to its window by an elastomer (rubber) seal 642 bonded to the window and to the sides and inner periphery of the shoe, the seals being connected to their radially innermost portions provide a continuous sleeve around pipe 532. Application of fluid pressure inside chamber 636 exceeding that outside the force applicator causes the shoes to be moved outwardly into bore wall engaging or set position; equalization of the pressures causes the elastic seals to retract the shoes back to the position shown. Even in retracted position the shoes are sufficiently close to bore wall engagement to serve as centralizing or guiding means for the mandrel of the force applicator. During drilling the mandrel is guided by the seals of the barrel heads of the cylinder anchor barrel and the seals of the cylinder heads of the piston and cylinder means, and by the piston moving in the cylinder of the piston and cylinder means, and by the ribs 519 of the spline sleeve moving in the channels 525 of the spline tube, and by the shoes of the mandrel anchor barrel moving in the bore hole. t

The flat sides 642 (FIG. 12) of the body 632 of the mandrel anchor provide fluid passages between such body and the bore wall. The shoes 640 are provided with teeth 644 which provide means to prevent axial and circumferential slippage between the mandrel anchor'barrel and bore wall when the shoes are in theextended or set position.

For supplying pressure fluid to the pipe 532 connecting to the Dyna-Dril or other drilling machine and to supply pressure fluid to the

conduits

605, 607 leading to the inner and outer spaces of the piston and cylinder means, and to chamber 636 of the mandrel anchor means and to conduit 546 leading to the cylinder anchor means, the manifold 630 isprovided with five

fluid passages

700, 702, 704, 706 and 708 as best shown in FIGS. 15 and 16. Passage 700 is in direct communication with the interior of tube 532 via counterbore 710, as shown in FIG. 10.

Referring to FIGS. 10 and 15, passage 702-communicates via radial passage 712 with axially extending passage 714 that connects to conduit 605 which is received in a counterbore at the end of passage 714. Similarly, passage 704 communicates via transverse passage 716 with axially extending passage 718 which connects to conduit 607 which is received in a counterbore at the end of passage 718.

Passage 706 communicates via radial passage 720 (FIG. 14) with axially extending passage 722 which is connected to conduit 546, the latter being received in a counterbore in passage 722.

Passage 708 (FIGS. 10 and 14-l6) connects directly with chamber 636 of the mandrel anchor means.

Referring now to FIGS. 11 and 16, the outer ends of

manifold passages

700, 702, 704, 706, 708 are connected to hose connection coupling means 724, 726, 728, 730, 732. The apparatus is thus adapted for operation by connection to five separate flexible, pressurefluid hoses extending through the earth bore to the outer end of the bore. To eliminate the possibility of tangling the hoses and to facilitate reeling and winching at the bore face, it is preferred to bundle them together to form a single line 87 as shown in FIGS. 1 and 17. It will be understood that this can be accomplished simply by helically wrapping a tape around the five hoses in order to hold them together in a single bundle, or a prefabricated multipassage hose can be used.

Referring now to FIG. 17, there is shown the in-hole apparatus as it is being launched into the earth bore through guide funnel 91 from suitable out-of-hole app'aratus. The out-of-hole apparatus includes a four wheeled trailer cart 798 on which is rotatably mounted reel 800 on which the hose line 87 is wound bysuitable means, e.g. with level windmeans as disclosed in the aforesaid contemporaneously executed Kellner application. The line 87 passes over suitable guide pulleys (not shown) to power winch 802. After several turns around winch 802 sufficient to establish the frictional engagement needed for pulling on the hose line with the desired force the hose line 87 connects to the hose coupling end of the force applicator 64.

Whe not in use the force applicator is carried in a storage and launch tube 804 affixed to the side of the cart. When it is desired to use the apparatus drilling machine 57 is placed inside an extension tube 806. The drilling machine is then connected to the force applicator 64 by sub 61 and the extension tube 806 is connected to storage and launch tube 804 by coupling 808. The cart 798 is positioned to place the end of extension tube 806 against guide funnel 91. With the cart 798 held stationary the force applicator can then be used to load the drilling machine to start the earth bore, purchase being obtained from the

tubes

804 and 806 as the force applicator moves therethrough into the earth bore. a

' The end of hose line 87 is connected through suitable swivel means, not shown, which may be like that disclosed in the aforesaid contemporaneously executed Kellner application, to pressure fluidsupply and control means carried by cart 798. For example, water emerging from the drill bit 53 and returning to receiving tank 810 through the earth bore 53 can be pumped out via pipe 812 by an electric motor driven pump (see FIG. 19) mounted in console 814. The water is then delivered to the flow passage of hose line 87 that delivers fluid to the drilling machine 57. The details of this could be the same as inthe. aforementioned contemporaneous Kellner application. Also mounted in console 814 is an air motor driven pump for hydraulic fluid together with suitable controls for supplying the hydraulic fluid to the two anchor means and to the piston and cylinder means of the force applicator. The details of such control and hydraulic fluid supply means are shown in FIG. 18. The symbols used in FIG. 18 are those of the United States of America Standards Institute, e.g. as illustrated and disclosed in the 1968/69 Fluid Power Handbook & Directory pages A/36-A/46.

Referring now to FIG. 18 there is shown a piston pump 900 driven by air motor 902 from a suitable source-of compressed air (not shown). The pump intake is connected to hydraulic fluid (oil, or preferably water because of its lower viscosity) tank 904 by line 906 through filter 908 and discharges through line 910 to accumulator 912.

Line 910 also is connected through line 914 and variable choke 916, line 917 and manual dump valve 918 to

branch lines

920, 922, with pressure gage 924 and relief valve 926 branching off from line 9.17.

Branch lines 920, 922'are connected to one-way pressure'control means 928, 930, each comprising a

check valve

932, 934 in parallel with a spring loaded

valve

936, 938. Valve 936 is normally open but closes chokes down to prevent downstream pressure from increasing above a set pressure. Valve 938 is normally closed and does not open until upstream pressure reaches a certain value, whereupon downstream and upstream pressure become equal. A pressure gage 940 is connected to pressure control means 928 downstream from valve 936.

Pressure control means 928 is connected throug line 942 to air actuated, spring centered, three position valve 944 and manually reversing valve 946 to mandrel anchor means 73, or, if the reversing valve 946 is moved to the opposite position from that shown, to cylinder anchor means 85. Tank 904 is connected through air operated three position valve 944 and reversing valve 946 to cylinder anchor means 85, or, if the reversing valve 946 is moved to the opposite position from that shown, to the mandrel anchor means 73.

if three position valve 944 is moved to the right from the position shown, in its mid position it will connect both anchor means 73, 85 to hydraulic line 942 and block off the connection thereof to tank 904. Further movement of valve 944 to the right will reverse the connection of the anchor means with respect to tank 904 and hydraulic line 942 from the position shown in the drawing. Valve 944 is moved from left to right and back again by air pressure through lines 950,952 which are connected through one way time delay (e.g. sec.) means 954, 956 and manual reversing valve 958 to

lines

960, 962. Line 960 is connected to a source (not shown) of air under pressure. Line 962 is connected to atmosphere.

The one-way time delay means 954, 956 comprise adjustable throttle valves (needle valves) 953, 955 in series with

air chambers

957, 959, the valves being bypassed by check valves'951, 96], whereby fluid can flow freely without time delay in the direction the check valves open but must fill the

chambers

957, 959 through

chokes

953, 955 before building up full pressure downstream when flowing in the other direction.

Air is also conducted from time delay means 954, 956 to air operated hydraulic reversing valve 964. Valve 964 controls flow through line 963 to tank 964 and from line 966 leading to time delay means 930.

Lines

966 and 963 connect through valve 964 to

hydraulic lines

968, 970, which in turn connect through one-way pressure regulator means 972, 974 to outer and

inner spaces

615, 613 on opposite sides of piston 81 carried on tube 532 inside cylinder 77. The one-way pressure regulator means 972, 974 comprise

pressure relief valves

971, 973, respectively in parallel with

check valves

975, 977.

Pressure gages

976, 978 con-. nected to

spaces

615, 613 indicate which space is pressurized.

The hydraulic fluid supply and control means provided by the apparatus shown in FIG. 18 is in the deactivated position due to dump valve 918 being in the dump position. In that position both

lines

942 and 966 are connected to discharge to tank 904 through

check valves

932 and 934 and dump valve 918. This means that whichever anchor means 73, 85 is connected to line 942 through

valves

944 and 946 is dumped to tank 904; likewise, whichever one of

spaces

615, 613 of the pistonand cylinder means 83 is connected to line 966 through valve 964 is also dumped to tank 904.

In addition, line 917 from the accumulator. is. also dumped to tank 904 through valve 918. The one of the anchor means not connected to line 942 is also dumped to tank 904, through line 990, and the one of the

spaces

615, 613 of the piston and cylinder means 81 that is not connected to line 966 is also dumped to tank 904, through line 963. Therefore, with this position of dump valve 918, the positions of cycle valve 958 and reverse valve 946 are immaterial, for the apparatus is fully deactivated.

To operate the apparatus .the dump valve 918 is moved to the right. This connects hydraulic line 917 to

lines

920, 922. With both the cycle valve 958 and the reverse valve 946 in the drill positions as shown, hydraulic fluid is supplied to cylinder anchor means 73 to set it in bore wall engaging position. As soon as the pressure builds up, valve 938 opens and hydraulic fluid is applied to the outer space'613 of the piston and cylinder means 81 to apply force to the drilling machine.

When the stroke limit of the force applicator is reached, the operator willbe apprised of that fact by a fall in pressure at the gate 992 (FIG. 19) on the outlet of electric motor driven pump 994 that picks up water from pipe 812 and delivers it to the drilling machine. Such a fall occurs because the drilling machine is no longer loaded.

The operator then moves cycle valve 958 to the left or reset position. This connects time delaymeans 954 to air vent 962 and allows the centering springs on valve 944 to move it to the right to centered position. At this time both the cylinder and mandrel anchor means 73, 85 are set. After the preset time delay, time delay means 956 connects air pressure line 960 to

lines

998 and 950 to move valve 964 to the left and valve 944 to the right. Cylinder anchor means 73 is thereby dumped and hydraulic line 966 is thereby connected to the inner space 613 of the piston and cylinder means to move the cylinder 77 to a new position farther inward in the earth bore. This will only take a minute, more orless, depending on the capacity of the hydraulic pump 900 and the volume of cylinder 77. The operator will be apprised of the fact that the stroke limit has been reached by a rise in pressure at gauge 978.

To resume drilling the operator moves cycle valve 958 to the right. Air line 950 is thereby dumped to atmospheric vent 962, allowing the springs of valve 944 to move it to its center position. Both the cylinder and piston anchor means 73, 85 are thereby connected to hydraulic line 942, setting the cylinder anchor means in addition to the already set mandrel anchor means 85. After the predetermined time delay of time delay means 954, air pressure line 960 will be connected to

lines

952 and 999, moving valves 944 to the left and valve 964 to the right. This will cause mandrel anchor means 85 to be connected to tank'904, retracting an-' chor means 85. As soon as pressure in the hydraulic line 922 is sufficient to open valve 938, hydraulic pressure fluid will be connected to outer space 615 of the piston and cylinder means 83, and the drilling machine will once more be loaded. The foregoing sequence can be repeated as the apparatus alternately reaches the end of the drilling stroke and then is reset.

If it is desired to remove the apparatus from the earth bore, the operator has two options. He can move dump valve 918 to the left, deactivating the piston and cylinder means and both anchor means. The winch 802 can then be operated to pull the hose bundle 87 and the force applicator 64 and the drilling machine 57 out of the earth bore.

Alternatively the operator can move the reverse valve 946 to the left or retract position. This will cause the mandrel anchor means 85 to be set, rather than the cylinder anchor means 73, when the cycle valve 958 is in the drill position. Therefore, when hydraulic fluid pressure is applied to the outer space 615 of the piston and cylinder means 83, the cylinder 77 is moved outwardly. When it reaches its stroke limit as indicated by a rise in pressure at gauge 976, the cycle valve is moved to the left to the reset position. This causes mandrel anchor means 85 to be retracted and cylinder anchor means 73 to be set, while hydraulic fluid pressure is applied to inner space 613 of the piston and cylinder means 83. The piston 81 of the piston and cylinder means is thereby moved outwardly to retract the apparatus from the earth bore. When its stroke limit is reached as indicated by a rise in pressure at gauge 978 the cycle valve is returned to the right or drill position.

1 By repeating the foregoing sequence, moving the cycle valve 958 back and forth as the stroke limits are reached, the apparatus is retracted from the earth bore under its own power.

During withdrawal of the apparatus from the earth bore the water or other pressure fluid supply to the drilling machine can be maintained. Alternatively, it can be continued at a reduced pressure by opening bypass throttle valve 1000 (FIG. 19) to a greater or lesser degree. If desired, the pressure fluid to the drilling machine can be shut off altogether by shutting down pump 994. This is accomplished by opening switch 1002 in the electric line connecting electric motor 1004 to a suitable source of electric power (not shown).

The apparatus is provided with a number of protective devices. Pressure relief valve 1006 prevents excessive water pressure from being supplied to the drilling machine.

Pressure regulating valves

972, 974 limit the pressure applied to the piston and cylinder means 83. Pressure regulating valve 936 limits the pressure applied to the two anchor means. Pressure relief valve 926 limits the pressure applied to the accumulator 912 and to the entire hydraulic system.

The pressure fluid supply and control system of FIG. 18 can be automated, if desired, in the same manner as described in detail in the aforementioned contemporaneously executed Kellner application, e.g. by including an out-of-hole pilot piston and cylinder means in series with one of the

lines

968, 970, and causing the motion of the pilot piston rod to actuate cycle valve 958 as the piston and cylinder means reaches the ends of its stroke.

While a preferred embodiment of the invention has I been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit of the invention.

That being claimed is:

1. Apparatus useful in earth boring comprising a wheeled cart, reel means carried by the cart, multipassage hose means wound on the reel, a storage and launch tube mounted on the cart, a bore wall engageable force applicator adapted to be supported in said tube and projectable therefrom, said hose means being including a piston connected to the mandrel and a cylinder in which the piston is slidable, anti-rotation means preventing relative rotation of the mandrel and cylinder, first hydraulically actuated anchor means connected to said cylinder at the end thereof nearest said drilling machine, second hydraulically actuated anchor means connected to said mandrel on the opposite side of said piston and cylinder means from said first anchor means adjacent said one end of the .force applicator to which said hose is connected, and pres sure fluid supply and control means connected to said hose means for separately supplying fluid to said drilling machine, each of said anchor means, and to the piston and cylinder means on opposite sides of said piston, said supply and control means including two sources of pressure fluid one of which is connected to a passage of said hose means that communicates with said drilling machine and the other which is carried by said cart and is in communication with separate passages in said hose means communicating with said two anchor means and with said piston and cylinder means on opposite sides of the'piston thereof, said control and supply means further including on said cart two separate means regulating the pressure of fluid supplied to said piston and cylinder means on opposite sides of the piston, a third means for regulating the pressure of fluid supplied to said anchor means, and two separate valve units, one unit connecting a selected one of said anchor means with said second source while disconnecting the other therefrom and the other unit connecting said second source to said piston and cylinder means on one side of the piston while disconnecting from said second source the piston and cylinder means at the other side of the piston, and gage means indicating the pressure supplied to said anchor means and to said piston and cylinder means on opposite sides of the piston thereof.

end of said hose means being connected to said force applicator.

3. Apparatus according to claim 2 wherein said support includes a cart and wheel means supporting said cart for movement in a horizontal direction, said storage and launch tube is mounted on said cart to be in a horizontal position when said cart is supported by said wheel means for such horizontal movement, said reel means is mounted for rotation about an axis parallel to the axis of said tube, said apparatus further including power winch means mounted for rotation about an axis that is vertical when said cart is supported by said wheel means as aforesaid, said hose means passing around said winch means between said reel means and said force applicator, the edge of the inner periphery of said storage and launch tube nearest said winch means being tangent to the outer periphery of said winch means.

4. Apparatus according to claim 2, said force applicator including a tubular mandrel providing fluid passage means to convey drilling fluid and providing means to apply axial force to a drilling machine when connected to the mandrel, two releasable anchor means each including a barrel disposed around the mandrel and sealed thereto at axially spaced positions defining a chamber between the barrel and mandrel, bore wall engageable means mounted in the barrel for motion outwardly relative to the mandrel axis and back toward it in response to the pressure differential between inside said chamber and outside said force applicator, and conduit means extending through the mandrel for supplying pressure fluid to said chamber,

piston and cylinder means for exerting an axial force on said mandrel including a piston connected to said mandrel, a cylinder disposed around said piston and axially slidable relative thereto, and separate conduit means extending through said mandrel for supplying 'pressure fluid to said cylinder on opposite sides of said piston,

the barrel of one of said, anchor means being fixedly connected to said mandrel,

the barrel of the other of said anchor means being fixedly connected to said cylinder, and

means preventing relative rotation of said cylinder and said mandrel,

said bore wall engageable means being engageable with the inner periphery of said storage and launch tube when moved outwardly under said pressure differential.

5. Apparatus according to claim 4 wherein said anchor means are disposed on opposite sides of said piston and cylinder means, said one anchor means fixedly connected to said mandrel being disposed adjacent the end of said force applicator to which is connected said hose means.

6. Apparatus according to claim 5, said hose means providing five parallel fluid paths, said hose means being connected to said force applicator by a manifold having five fluid passages therethrough, said five fluid passages being connected respectively to said two anchor means and to two opposite sides of said piston and cylinder means and to said fluid passage means to convey drilling fluid, said manifold also providing the means by which the barrel of said one anchor means is connected to said mandrel.

7. Apparatus useful in earth boring, said apparatus comprising a force applicator includng a tubular mandrel having means at one end thereof for makingconnection at least indirectly with a drilling machine, said one end constituting the inner end of the mandrel and the opposite end of the mandrel constituting the outer end of the mandrel,

said mandrel providing means to apply force to such drilling machine when connected thereto,

bore wall engaging means concentric piston and cylinder means for applying axial force to said mandrel incluidng a piston connected to said mandrel and a cylinder within which said piston is axially slidably disposed,

cylinder anchor means for releasably anchoring said cylinder to the wall of an earth bore,

spline means for preventing relative rotation of said mandrel and cylinder while allowing relative axial motion thereof, and

mandrel anchor means for releasably anchoring said mandrel to the wall of an earth bore,

each of said anchor means including bore wall engageable means extending radially outwardly beyond the outer periphery of said mandrel even 'when said anchor means is released from bore wall engaging position, whereby said anchor means serve also as guide means for said mandrel,

said releasable anchor means being disposed at opposite ends of said barrel and cylinder means.

8. Apparatus according to claim 7,

said cylinder anchor means being connected to said cylinderat the end thereof nearest said inner end of the mandrel,

said mandrel anchor means being connected to said mandrel at the side of said piston and cylinder means nearest the outer end of said mandrel. 9. Apparatus according to claim 8 wherein said mandrel is tubular providing fluid passage means to supply pressure fluid from the outer end of the mandrel to a drillingmachine connected to said inner end of said mandrel,

each of said anchor means including return fluid passage means to conduct past said anchor means exteriorly of said mandrel pressure fluid returning from such drilling machine between the force applicator and an earth bore therearound,

said piston and cylindermeans lying between said anchor means and spacing them apart at all times, thereby assuring that said return fluid passage means in one anchor means is not blocked by the bore wall engaging means of the other anchor means when said mandrel moves relative to said cylinder.

10. Apparatus according to claim 9,

each of said anchor means including a barrel around the mandrel, means sealing between the barrel and mandrel at positions spaced apart axailly of the mandrel forming between said seals and said barrel and said mandrel a chamber,

. each bore wall engageable means of each of said anchor means comprising a shoe mounted in a window in the barrel of said anchor means and projectable radially outwardly by pressure fluid within the chamber of said anchor means,

said force applicator further including a manifold connected to the outer end of said mandrel anchor means providing means to connect the force applicator to means for separately supplying pressure fluid to each of said anchor means, the piston and cylinder means on both sides of said piston, and to a drilling machine connected to the inner end of said force applicator.

11. Apparatus according to claim 10,

said mandrel being also connected to the outer end of the barrel of said mandrel anchor means and providing the outermost of one of said seals between said mandrel and said mandrel anchor means.

12. Apparatus according to claim 11,

said manifold including a first fluid passage connected at its inner end with the outer end of said mandrel in communication with said fluid passage means to supply pressure fluid to a drilling machine connected to said one end of the mandrel,

said manifold further including a second fluid passage directly connected at its inner end with the chamber of said mandrel anchor means,

said manifold further including third, fourth and fifth fluid passages connected to conduits in said mandrel leading to said cylinder anchor means and to said piston and cylinder means on opposite sides of said piston.

13. Apparatus useful in earth boring, said apparatus comprising a force applicator including a mandrel having means at one end thereof for making connection at least indirectly with a drilling machine, said one end constituting the inner end of the mandrel and the opposite end of the mandrel constituting the outer end of the mandrel, v

piston and cylinder means for applying axial force to said mandrel including a piston connected to said mandrel and a cylinder within which said piston is axially slidably disposed,

spline means for preventing relative rotation of said mandrel and cylinder while allowing'relative axial motion thereof, and

said mandrel being tubular providing fluid passage means to supply pressure fluid from the outer end of the mandrel to a drilling machine connected to said inner end of the mandrel,

each of said anchor means incluidng a barrel around the mandrel, means sealing between the barrel and mandrel at positions spaced apart axially of the mandrel forming between said seals and said barrel and said mandrel a chamber,

each of said anchor means further including bore wall engageable means comprising a shoe mounted in a window in the barrel of said anchor means and projectable radially outwardly by pressure fluid with the chamberof said anchor means,

said force applicator further including multipassage means for separately supplying pressure fluid to each of said anchor means and to the piston and cylinder means at each side of said piston,

flexible hose means connected at one end to the outer end of said force applicator and including first, second, third, fourth, and fifth channels, the first of said five channels communicating with said fluid passage means to supply pressure fluid to a drilling machine connected to theforce applicator, and said second, third, fourth and fifth channels communicating respectively via said multipassage means with said two anchor means and the piston and cylinder means on opposite sides of the piston thereof,

pressure fluid supply and control means connected to the other end of said hose means for selectively supplying pressure fluid to said channels as desired,

said pressure fluid supply and control means including a first source of pressure fluid for supplying drilling fluid to said' first channel and a second is source of pressure fluid for supplying hydraulic fluid to the remainder of said channels,

said pressure fluid supply and control means further including 1 a first valve unit selectively to connect one of said second and third channels to said second source of pressure fluid and disconnect the other therefrom and a second valve unit selectively to connect one of said fourth and fifth channels to said second source of pressure fluid and disconnect the other therefrom.

14. Apparatus according to claim 13, said pressure fluid supply and control means including means independently to regulate the pressure of fluid supplied to each of said fourth and fifth channels.

15. Apparatus according to claim 14 wherein said first valve is a three position valve in a center position of which both of said second and third channels are connected to said second source of 7 pressure fluid thereby to insure that shifting the condition of the apparatus from that in which an anchor means is set to that in which the other anchor means is set, one of said anchor means is always set.

16. Apparatus useful in earth boring including a force applicator comprising a tubular mandrel, a cylinder around the outside of the mandrel, a piston affixed to the mandrel slidable in the cylinder, two barrels around the mandrel, one barrel being connected at one end to one end of the cylinder, the other barrel being connected at one end to the mandrel at the opposite end of said cylinder from said first barrel, spline means connecting said mandrel and cylinder, hydraulically actuatable shoes carried by each barrel, first conduit means inside said mandrel extending from a port in said mandrel inside said first barrel through saidcylinder and second barrel to the end of said mandrel, second conduit means extendng inside said mandrel from said end of the mandrel to a port in the mandrel communicating with said cylinder on one side of said piston, third conduit means extending inside said mandrel to a port in the mandrel communicating with said cylinder 0n the other side of said piston, the mandrel being otherwise clear of conduits leaving a passage means therethrough for communication with a drilling machine when connected to the other end of the mandrel, and passage means communicating with the interior of said second barrel.

17. Apparatus according to claim 16 including a manifold connected to the first said end of the mandrel for connecting multipasage hose means to the three conduits in the mandrel and said passage means in the mandrel and said passage means communicating with the interior of the second barrel, said manifold also providing means by which said second barrel is connected to the mandrel as aforesaid, and said passage means communicating with the interior of said second barrel being formed insaid manifold.

18. Apparatus useful in earth boring including a mandrel, a bore around the outside of the mandrel, a manifold which at one end provides means mechanically connecting one end of the barrel to one end of the mandrel, hydraulically extendable bore wall engaging means carried by the barrel, first fluid passage means through the manifold connecting the space inside the barrel outside the mandrel with the other end of the manifold, second fluid passage means through the manifold connecting the interior of the mandrel with said other end of the manifold, and means at said other end of the manifold for connecting said fluid passage means with a flexible hose bundle.

Claims

1. Apparatus useful in earth boring comprising a wheeled cart, reel means carried by the cart, multipassage hose means wound on the reel, a storage and launch tube mounted on the cart, a bore wall engageable force applicator adapted to be supported in said tube and projectable therefrom, said hose means being connected to one end of said applicator, a drilling machine connected to the other end of said force applicator, said force applicator including a tubular mandrel providing means for conveying operating fluid to said drilling machine, hydraulically actuated piston and cylinder means for applying axial force to the mandrel and including a piston connected to the mAndrel and a cylinder in which the piston is slidable, anti-rotation means preventing relative rotation of the mandrel and cylinder, first hydraulically actuated anchor means connected to said cylinder at the end thereof nearest said drilling machine, second hydraulically actuated anchor means connected to said mandrel on the opposite side of said piston and cylinder means from said first anchor means adjacent said one end of the force applicator to which said hose is connected, and pressure fluid supply and control means connected to said hose means for separately supplying fluid to said drilling machine, each of said anchor means, and to the piston and cylinder means on opposite sides of said piston, said supply and control means including two sources of pressure fluid one of which is connected to a passage of said hose means that communicates with said drilling machine and the other which is carried by said cart and is in communication with separate passages in said hose means communicating with said two anchor means and with said piston and cylinder means on opposite sides of the piston thereof, said control and supply means further including on said cart two separate means regulating the pressure of fluid supplied to said piston and cylinder means on opposite sides of the piston, a third means for regulating the pressure of fluid supplied to said anchor means, and two separate valve units, one unit connecting a selected one of said anchor means with said second source while disconnecting the other therefrom and the other unit connecting said second source to said piston and cylinder means on one side of the piston while disconnecting from said second source the piston and cylinder means at the other side of the piston, and gage means indicating the pressure supplied to said anchor means and to said piston and cylinder means on opposite sides of the piston thereof.

2. Apparatus useful in earth boring, said apparatus comprising a support, reel means carried by the support, hose means wound on the reel, a storage and launch tube carried by said support, a bore wall engageable force applicator disposed in said tube, one end of said hose means being connected to said force applicator.

4. Apparatus according to claim 2, said force applicator including a tubular mandrel providing fluid passage means to convey drilling fluid and providing means to apply axial force to a drilling machine when connected to the mandrel, two releasable anchor means each including a barrel disposed around the mandrel and sealed thereto at axially spaced positions defining a chamber between the barrel and mandrel, bore wall engageable means mounted in the barrel for motion outwardly relative to the mandrel axis and back toward it in response to the pressure differential between inside said chamber and outside said force applicator, and conduit means extending through the mandrel for supplying pressure fluid to said chamber, piston and cylinder means for exerting an axial force on said mandrel including a piston connected to said mandrel, a cylinder disposed around said piston and axially slidable relative thereto, and separate conduit means extending through said mandrel for supplyiNg pressure fluid to said cylinder on opposite sides of said piston, the barrel of one of said anchor means being fixedly connected to said mandrel, the barrel of the other of said anchor means being fixedly connected to said cylinder, and means preventing relative rotation of said cylinder and said mandrel, said bore wall engageable means being engageable with the inner periphery of said storage and launch tube when moved outwardly under said pressure differential.

7. Apparatus useful in earth boring, said apparatus comprising a force applicator includng a tubular mandrel having means at one end thereof for making connection at least indirectly with a drilling machine, said one end constituting the inner end of the mandrel and the opposite end of the mandrel constituting the outer end of the mandrel, said mandrel providing means to apply force to such drilling machine when connected thereto, bore wall engaging means concentric piston and cylinder means for applying axial force to said mandrel incluidng a piston connected to said mandrel and a cylinder within which said piston is axially slidably disposed, cylinder anchor means for releasably anchoring said cylinder to the wall of an earth bore, spline means for preventing relative rotation of said mandrel and cylinder while allowing relative axial motion thereof, and mandrel anchor means for releasably anchoring said mandrel to the wall of an earth bore, each of said anchor means including bore wall engageable means extending radially outwardly beyond the outer periphery of said mandrel even when said anchor means is released from bore wall engaging position, whereby said anchor means serve also as guide means for said mandrel, said releasable anchor means being disposed at opposite ends of said barrel and cylinder means.

8. Apparatus according to claim 7, said cylinder anchor means being connected to said cylinder at the end thereof nearest said inner end of the mandrel, said mandrel anchor means being connected to said mandrel at the side of said piston and cylinder means nearest the outer end of said mandrel.

9. Apparatus according to claim 8 wherein said mandrel is tubular providing fluid passage means to supply pressure fluid from the outer end of the mandrel to a drilling machine connected to said inner end of said mandrel, each of said anchor means including return fluid passage means to conduct past said anchor means exteriorly of said mandrel pressure fluid returning from such drilling machine between the force applicator and an earth bore therearound, said piston and cylinder means lying between said anchor means and spacing them apart at all times, thereby assuring that said return fluid passage means in one anchor means is not blocked by the bore wall engaging means of the other anchor means when said mandrel moves relative to said cylinder.

10. Apparatus according to claim 9, each of said anchor means including a barrel around the mandrel, means sealing between the barrel and mandrel at positions spaced apart axailly of the mandrel forming between said seals and said barrel and said mandrel a chamber, each bore wall engageable means of each of said anchor means comprising a shoe mounted in a window in the barrel of said anchor means and projectable radially outwardly by pressure fluid within the chamber of said anchor means, said force applicator further including a manifold connected to the outer end of said mandrel anchor means providing means to connect the force applicator to means for separately supplying pressure fluid to each of said anchor means, the piston and cylinder means on both sides of said piston, and to a drilling machine connected to the inner end of said force applicator.

11. Apparatus according to claim 10, said mandrel being also connected to the outer end of the barrel of said mandrel anchor means and providing the outermost of one of said seals between said mandrel and said mandrel anchor means.

12. Apparatus according to claim 11, said manifold including a first fluid passage connected at its inner end with the outer end of said mandrel in communication with said fluid passage means to supply pressure fluid to a drilling machine connected to said one end of the mandrel, said manifold further including a second fluid passage directly connected at its inner end with the chamber of said mandrel anchor means, said manifold further including third, fourth and fifth fluid passages connected to conduits in said mandrel leading to said cylinder anchor means and to said piston and cylinder means on opposite sides of said piston.

13. Apparatus useful in earth boring, said apparatus comprising a force applicator including a mandrel having means at one end thereof for making connection at least indirectly with a drilling machine, said one end constituting the inner end of the mandrel and the opposite end of the mandrel constituting the outer end of the mandrel, said mandrel providing means to apply force to such drilling machine when connected thereto, piston and cylinder means for applying axial force to said mandrel including a piston connected to said mandrel and a cylinder within which said piston is axially slidably disposed, cylinder anchor means for releasably anchoring said cylinder to the wall of an earth bore, spline means for preventing relative rotation of said mandrel and cylinder while allowing relative axial motion thereof, and mandrel anchor means for releasably anchoring said mandrel to the wall of an earth bore, said mandrel being tubular providing fluid passage means to supply pressure fluid from the outer end of the mandrel to a drilling machine connected to said inner end of the mandrel, each of said anchor means incluidng a barrel around the mandrel, means sealing between the barrel and mandrel at positions spaced apart axially of the mandrel forming between said seals and said barrel and said mandrel a chamber, each of said anchor means further including bore wall engageable means comprising a shoe mounted in a window in the barrel of said anchor means and projectable radially outwardly by pressure fluid with the chamber of said anchor means, said force applicator further including multipassage means for separately supplying pressure fluid to each of said anchor means and to the piston and cylinder means at each side of said piston, flexible hose means connected at one end to the outer end of said force applicator and including first, second, third, fourth, and fifth channels, the first of said five channels communicating with said fluid passage means to supply pressure fluid to a drilling machine connected to the force applicator, and said second, third, fourth and fifth channels communicating respectively via said multipassage means with said two anchor means and the piston and cylinder means on opposite sides of the piston thereof, pressure fluid supply and control means connected to the other end of said hose means for selectively supplying pressure fluid to said channels as desired, said pressure fluid supply and control means incluDing a first source of pressure fluid for supplying drilling fluid to said first channel and a second source of pressure fluid for supplying hydraulic fluid to the remainder of said channels, said pressure fluid supply and control means further including a first valve unit selectively to connect one of said second and third channels to said second source of pressure fluid and disconnect the other therefrom and a second valve unit selectively to connect one of said fourth and fifth channels to said second source of pressure fluid and disconnect the other therefrom.

15. Apparatus according to claim 14 wherein said first valve is a three position valve in a center position of which both of said second and third channels are connected to said second source of pressure fluid thereby to insure that shifting the condition of the apparatus from that in which an anchor means is set to that in which the other anchor means is set, one of said anchor means is always set.

16. Apparatus useful in earth boring including a force applicator comprising a tubular mandrel, a cylinder around the outside of the mandrel, a piston affixed to the mandrel slidable in the cylinder, two barrels around the mandrel, one barrel being connected at one end to one end of the cylinder, the other barrel being connected at one end to the mandrel at the opposite end of said cylinder from said first barrel, spline means connecting said mandrel and cylinder, hydraulically actuatable shoes carried by each barrel, first conduit means inside said mandrel extending from a port in said mandrel inside said first barrel through said cylinder and second barrel to the end of said mandrel, second conduit means extendng inside said mandrel from said end of the mandrel to a port in the mandrel communicating with said cylinder on one side of said piston, third conduit means extending inside said mandrel to a port in the mandrel communicating with said cylinder on the other side of said piston, the mandrel being otherwise clear of conduits leaving a passage means therethrough for communication with a drilling machine when connected to the other end of the mandrel, and passage means communicating with the interior of said second barrel.

17. Apparatus according to claim 16 including a manifold connected to the first said end of the mandrel for connecting multipasage hose means to the three conduits in the mandrel and said passage means in the mandrel and said passage means communicating with the interior of the second barrel, said manifold also providing means by which said second barrel is connected to the mandrel as aforesaid, and said passage means communicating with the interior of said second barrel being formed in said manifold.