US3696872A

US3696872A - Drill string joint breaking means

Info

Publication number: US3696872A
Application number: US147988A
Authority: US
Inventors: Nils Gunnar Jonsson
Original assignee: Atlas Copco AB
Current assignee: Craelius AB
Priority date: 1970-06-15
Filing date: 1971-05-28
Publication date: 1972-10-10
Anticipated expiration: 1989-10-10
Also published as: CH542993A; NO131517B; FR2097870A5; NO131517C; SE341169B; ZA713469B; GB1295217A; JPS518361B1; DE2128362A1; CA939662A; FI54832B; FI54832C

Abstract

A rock drill has a chuck which is arranged to be displaced along a feed bar by means of a feed motor. The chuck is of the kind which is hydraulically actuated and grips the drill pipe when pressurized and it is rotated by means of a reversible hydraulic motor having two alternative supply conduits. The chuck is connected to the supply conduit for providing reverse rotation by means of a conduit in which a delaying valve is arranged. Thus, when the supply conduit for providing reverse rotation is pressurized upon actuation of a manually operated valve, the drill pipe being firmly held by a drill pipe holder, the delaying valve delays the supply of hydraulic fluid to the chuck until the hydraulic rotation motor and thereby the chuck has started its backward rotation so that the kinetic energy of the chuck and the motor is utilized for breaking a drill string joint located between the holder and the chuck.

Description

United States Patent Jonsson 1 Oct. 10,1972

[54] DRILL STRING JOINT BREAKING MEANS [73] Assignee: Atlas Copco Aktiebolag,

Sweden [22] Filed: May 28,1971

[21] Appl.No.: 147,988

Nacka,

[30] Foreign Application Priority Data June 15, 1970 Sweden ..8254/70 [52] US. Cl. ..173/149, 8l/57.l9, 173/164, 279/4 [51] Int. Cl ..E21c l/l0 [58] Field of Search.....173/l64, 152; 175/85; 279/4; 81/57.]9; 166/725, 315; 192/.096

Primary Examiner-Emest R. Purser Attorney-Munson & Fiddler ABSTRACT A rock drill has a chuck which is arranged to be displaced along a feed bar by means of a feed motor. The chuck is of the kind which is hydraulically actuated and grips the drill pipe when pressurized and it is rotated by means of a reversible hydraulic motor having two alternative supply conduits. The chuck is connected to the supply conduit for providing reverse rotation by means of a conduit in which a delaying valve is arranged. Thus, when the supply conduit for providing reverse rotation is pressurized upon actuation of a manually operated valve, the drill pipe being firmly held by a drill pipe holder, the delaying valve delays the supply of hydraulic fluid to the chuck until the hydraulic rotation motor and thereby the chuck has started its backward rotation so that the kinetic energy of the chuck and the motor is utilized for breaking a drill string joint located between the holder 12 Claims, 9 Drawing Figures [56] References Cited UNITED STATES PATENTS and the Chuck- 3,021,739 2/1962 Grundmann ..81/57.19

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PATENTEDUCT 10 m2 sum 1 or 5 I NILS GUNNAR JONSSON I NVE NTOR.

BY MUNSON & FIDDLER PATENTEDnm 10 I972 3.696, 8 72 sum 2 or 5 Fig.4

U U NILS GUNNAR JONSSON INVENTOR.

BY MUNSON & FIDDLER PATENTEDncno m2 3.696.872

SHEET 3 OF 5 I1 000 000 Kg mm H|I[l INVENTOR.

48 NILS GUNNAR JONSSON MUNSON & FIDDLER PKTE'N'TEBnm 10 m2 SHEET UF 5 INVENTOR.

NILS GUNNAR JONSSON MUNSON & FIDDLER DRILL STRING JOINT BREAKING MEANS This invention relates to a drill string joint breaking means which is used in connection with a rock or earth drilling apparatus and comprises a drill string holder and a power rotated chuck in axial alignment which are arranged for gripping the drill string and breaking a drill string joint located between the holder and the chuck. More specifically, the chuck is the chuck which is used also during drilling for rotating and feeding the drill string.

In rock drilling, the joints of the drill string will sometimes become so tight during drilling that the rotation motor is not capable of breaking the joints and it is therefore an object of the invention to provide for a reliable breaking of the drill string joints.

The above and other objects of the invention are obvious from the following description and from the accompanying drawings in which rock drilling apparatus including drill string joint breaking means in accordance with the invention is described by way of example.

In the drawings, FIG. 1 is a side view, partly in section, of the rock drilling apparatus arranged for vertical drilling; FIG. 2 is a front elevation partly in section, of the drilling apparatus illustrated in FIG. 1; FIG. 3 is an enlarged section on line 3-3 in FIG. 1; FIG. 4 is an enlarged section of line 44 in the FIGS. 1 and 5; FIG. 5 is an enlarged section substantially on line 55 in FIG. 1, a chuck being illustrated in a section taken along line 5-5 in FIG. 4; FIG. 6 is a diagram of the pressure fluid system of the drilling apparatus illustrated in the FIGS. l-S; FIG. 7 is a longitudinal section through a valve which is indicated in FIG. 6', and FIGS. 8 and 9 are longitudinal sections through modified embodiments of the valve shown in FIG. 7.

In the various figures, corresponding details have been given the same reference numeral.

The drilling apparatus illustrated in FIGS. 1-5 has a feed bar 11 which is supported by expanding units 12. Alternatively the feed bar may be carried by a wheeled substructure or be supported in another suitable way. A slide 13, which carries a drill 14, is slidable along the feed bar 11 by means of two parallel chains 15, a chain 16, and a feed motor 17 in the form of a cylinder with a reciprocating piston rod 20. The feed motor 17 has two

supply conduits

18, 19. If pressure fluid is supplied through the supply conduit 18, the piston rod 20 retracts and the chain 16 pulls the slide 13 forwards, i.e. downwards in FIG. 1. If, alternatively, pressure fluid is supplied through the supply conduit 19, the slide 13 is pulled backwards, i.e. upwards in FIG. 1, by means of the chains 15.

A stationary drill pipe holder or chuck 21 of the vicetype is disposed at the forward portion of the feed bar 11. By means of Belleville springs 24, FIG. 3, its jaws 22 are biased to grip a drill string in the form of a drill pipe 23. By the action of pressure fluid upon a piston 24a, the force of the springs 24 is overcome and the jaws 22 are forced to release the drill pipe 23. The pressure fluid is supplied through a conduit 25.

The drill pipe 23 comprises several pipe lengths and a drill bit 26 which are joined by screw joints. For rock drilling, the drill bit 26 may be a pipe-like diamond drill bit and the first pipe element may be a so called core pipe for collecting a core. A swivel 49 supplies flush water to the drill pipe.

A chuck 27 with a housing 28 is a part of the drill 14 which in FIG. 5 is illustrated in a sectional view. This chuck 27 is rotatably journalled in the housing 29 of the drill 14 by means of a roller bearing 30 and a ball bearing 31. Thus, the chuck 27 is displaced with the drill 14.

A reversible, pressure fluid actuated rotary motor 32 is arranged to rotate the chuck 27 over a gearing which comprises

gears

33, 34. The gear 33 is fixed to the output shaft of the rotary motor 32 by means of a key 35, and the gear 34 is fixed to the housing 28 of the chuck 27 by means of another key 35. The rotary motor 32 has two

alternative supply conduits

36, 37. When pressure fluid is supplied through the conduit 36, the motor 32 rotates forward, and when pressure fluid is supplied through the conduit 37, the motor reverses.

Pressure fluid to the chuck 27 is supplied to .a passage 40 in the housing 28 of the chuck by means of a conduit 38 and an annular groove 39 in the housing 29. Oil is permitted to leak through an annular gap 41 between the rotating chuck 27 and the non-rotating housing 29. This oil is collected and conveyed back to a sump 52 by means of a drain conduit 42.

In the chuck housing 28, a sleeve-like piston element 43, which has flanges and is made of an elastomer, is sealingly clamped by means of a spacer sleeve 44 and a cover 45. When pressure fluid is supplied through the conduit 38, the piston element 43 forces four jaws 46 of the chuck 27 to grip the drill pipe 23. Spring plates 47 are disposed between the jaws 46 to hold the jaws in disengaged position when there is no pressure in the conduit 38. The jaws 46 are guided by guiding pins 48, which transmit torque directly from the housing 28 of the chuck 27 to the jaws 46 so that the piston element 43 is not subject to torque when the chuck is rotated.

In the conduit diagram, FIG. 6, the

chucks

21 and 27, the feed motor 17, the rotary motor 32, and the

conduits

18, 19, 25, 36, 37, 38, 42 all of which are described above, are represented. The reference numeral 51 refers to a pressure fluid supplying unit, which comprises a sump 52 and a pump 53 which is driven by a motor E. Normally, the pressure fluid supplying unit 51 is situated some distance away from the drilling apparatus. The pump 53 supplies pressure fluid, preferably pressure oil, through a main conduit 54 to a control unit 56 which is indicated by means of dashand-dot lines. Preferably the pump 53 is pressure compensated so that it supplies oil of a constant pressure independently of the amount of oil utilized. By means of a return conduit 55, oil is returned from the control unit 56 to the sump 52.

A manually operated control valve 57 for the rotary motor 32 is supplied with pressure fluid from the main conduit 54. This valve 57, which is called the rotation control valve, has three alternative positions which are referred to as positions a, b and c and represented in FIG. 6 by the corresponding squares a, b,c of the symbol of the valve. With the rotation control valve in position b, as illustrated in the figure, the

conduits

36, 37 are connected to the return conduit 55, and, thus, the rotary motor does not rotate. With the rotation control valve 57 in position a, the conduit 36 is supplied with pressure oil from the main conduit 54, and the conduit 37 is drained through the return conduit 55. Therefore, the rotary motor 32 rotates forward. With the valve in the position 0, the conduit 36 is drained and the conduit 37 is supplied with pressure oil so that the rotary motor 32 rotates in reverse direction.

The axial displacement of the drill 14 is controlled by means of a manually operated control valve 58 which is referred to as the feed control valve. This feed control valve 58 has also'three positions which are referred to as a, b, 0. With the feed control valve 58 in position b, as illustrated in the figure, the two

supply conduits

18, 19 of the feed motor 17 are connected to theretum conduit 55, and the drill 14 does not move axially. If, simultaneously, the rotation control valve 57 is in position b, the main conduit 54 is directly connected to the return conduit 55 and the entire drilling apparatus is idling. The feed control valve 58 is supplied with pressure oil through a conduit 59 independently of the position of the rotation control valve 57. With the feed con trol valve 58 in position a, pressure oil is supplied to the conduit 18, and the conduit 19 is connected to the return conduit 55. Thus, the drill 14 advances. With the feed control valve 58 in position c, pressure oil is supplied to the conduit 19, and the conduit 18 is drained. Therefore, thedrill 14 now retracts.

The

supply conduits

25, 38 of the two

chucks

21, 27 are branches of a common supply conduit 60. With a manually operated selector valve 61 in a position a, the supply conduit 18 of the feed motor 17 is connected to the conduit 60. With the selector valve in a position c, alternatively, the other supply conduit 19 is connected to the conduit 60. With the selector'valve in a position b, the conduit 60 is not connected to either of the

conduits

18, 19. The conduit 38 of the movable chuck 27 is connected to both of the

supply conduits

36, 37 of the rotary motor by means of two

connection conduits

62, 63. The connection conduits are provided with

valves

64, 75 which permit flow only in the direction towards the conduit 38. The valve 64 is a simple one-way valve but the valve 75 is a delaying valve which also acts as a one-way valve. Between the junctions of the connection conduits 62,163 with the conduit 38 and the junction of the conduits 25 with the conduit 38, a one-way restrictor 65 is arranged in the conduit 38. A manually operated shut-off valve 66 is also arranged in the com duit 38.

The valve 75 will now be described with reference to FIG. 7. It consists of a slide 76.sliding in a cylinder 77 which .forms part of the conduit 63. The cylinder 77 ends in a chamber 78. A bore 79 in the end face 80 of the slide 76 is in communication with a transverse bore 81. The slide 76 has a head 82 which slides in a cylinder 83 and, as shown in the figure, it is biased against its end position by means of a spring 84 in the closed cylinder chamber 85 which is separated by the piston 82. In this position, the slide 76 keeps the conduit 63 closed. The motor 32 starts rotating backward when its supply conduit 37 is pressurized. Simultaneously the end face 80 of the slide will be loaded by pressure oil and the slide moves therefore to the left in FIG. 7, but since the oil in the cylinder chamber 85 can only escape through a restricted bore 86, the piston 82 will dampen the speed of the slide. The motor 32 has therefore already rotated for instance one revolution before the bore 81 reaches the chamber 78 so that the chuck 27 is supplied with pressure oil and grips the drill pipe. In the moment of gripping, the chuck 27 transmits to the drill pipe the torque of the motor 32 and the torque which emanates from the kinetic energy of the chuck 27, the motor 32, and the gearing. The torque available for breaking a joint can thus be many times the output torque of the motor 32. As soon as the supply of pressure oil through either of the conduits 62, 63.stops, the

chuck 27 is relieved of pressure because of its draining through the restriction 65 and through the annular leak space 41.

In the modified form shown in FIG. 8, the restricted bore 86 is replaced by a restricted groove which also is denoted by 86. Since, in thisdesign of the head 82, the head is not provided with any sealing ring, there will be some leakage also through the clearance space between the head and the cylinder 83. The design shown in FIG. 9 is identical with the one in FIG. 7, but a passage 87 with a one-way valve 88 is arranged to permit the spring 84 to return the slide 76 to the closed end position in which the slide is shown.

An adjustable pressure reducing valve 67 in the conduit 18 ,sets an upper limit on the feed power. A manometer 68 indicates the feed pressure. Another manometer 69 indicates the pressure in the main conduit 54. In the conduit 19 of the feed motor 17, an adjustable valve of the relief-valve type is arranged. This valve closes automatically when the pressure in the conduit 19 is lower than a predetermined pressure. The purposes of this valve 70 are to compensate for the weight of the drill 14 and the drill pipe 23 during drilling and to prevent the drill with the drill string from moving downwards because of the weight only. A oneway valve 71 is connected in parallel with the valve 70, and retraction of the drill 14 is permitted. When drilling upwards is to be effected, the

valves

70, 71 are connected in the conduit 18 instead of the conduit 19.

For effecting idle run, both the rotation control valve 57 and the feed control valve 58 are set in the neutral positions, i.e. the positions b. The drill pipe 23 is then held by the stationary chuck 21. When drilling is to be started, at first the selector valve 61 is set into position b, then, the rotation control valve 57 is moved into position a. Now, pressure oil flows through the connection conduit 62 to the

chucks

21 and 27 so that simultaneously, the chuck 27 grips the drill pipe, the chuck 21 releases the drill pipe, and the chuck 27 begins to rotate. Now, when the feed control valve 58 is moved to position a, the drill 14 advances. The advance stops automatically when the piston rod 20 of the feed motor 17 reaches its retracted stop position provided the feed control valve 58 is not shifted before this position is reached.

When the rotation control valve 57 is re-set into the position b, the

chucks

21, 27 alternate the engagement tion control valve 57 and thefeed control valve 58 are set in the positions a.

For withdrawing of the drill pipe 23, the selector valve 61 is set in position 0, and the rotation control valve 57 in position b. The feed control valve 58 is now used as a common control valve for the two

chucks

21, 27 and the feed motor 17. When the feed control valve 58 is moved from position b, the neutral position, to the position c, the chuck 21 releases the drill pipe, but the chuck 27 grips the drill pipe and withdraws it. When the feed control valve 58 is moved into position a, the chucks alternate engagement automatically, and the drill l4 advances without pushing the drill pipe forward. This is repeated, if necessary, until the drill pipe is withdrawn an appropriate length. Then, the feed control valve 58 is moved to the position b, the neutral position, and the rotation control valve 57 is moved to the position 0. Now, the chuck 27 rotates in reverse direction and the supply conduit 60, common to the two

chucks

21, 27, is drained through the selector valve 61 and the feed control valve 58. Through the connection conduit 62, however, the movable chuck 27 is sup plied with pressure oil. On account of the restrictor 65, there is oil pressure on this chuck 27, and the chuck 27 grips the drill pipe. The stationary chuck 21, maintains its grip since the flow through the restriction valve is drained through the common supply conduit 60 of the

chucks

21, 27. Therefore, if there is a screw joint of the drill pipe between the chucks, this joint will be broken mechanically when the

control valves

57, 58 are in these positions. The delaying valve 75 ensures breaking of very tight joints as previously described.

When it is desired to reinsert the drill pipe in the drill hole, the selector valve 61 is set in position a. The movable chuck 27 will now bring the drill pipe 23 forward when the drill 14 advances, and the stationary chuck 21 will hold the drill pipe during retraction of the drill. With the rotation control valve 57 maintained in the position b, the neutral position, this reinsertion is controlled by means of the feed control valve 58. When the drill pipe 23 has been introduced so far that the stationary chuck 21 holds the outer end of the pipe, another pipe element is manually screwed on loosely, and the drill 14 is retracted. Then the rotation control valve 57 is moved to the position a. As a result, the movable chuck 27 engages and rotates the pipe element, while the stationary chuck 21 holds the drill pipe 23 because of the restriction valve 65 which is the case also during breaking of joints. Thus, the joint is made. Then, the drill pipe 23 is again inserted so far that the chuck 21 will again hold the outer end of the drill pipe, and the sequence is repeated.

In order to permit inserting of the drill bit and the first drill-pipe element through the two

chucks

21, 27, the chucks must be open simultaneously. For this purpose, the operator closes the shut-off valve 66, sets the rotation control valve 57 in the position b, the neutral position, and sets the selector valve 61 and the feed control valve 58 in the position a. As result, the drill l4 advances until it stops in its advanced stop position. The two chucks 21, 27 are now open. Alternatively, the selector valve 61 and the feed control valve 58 can be set in the position 0 so that the drill 14 stops in its retracted stop position. V

In the drilling apparatus described above, the two

chucks

21, 27 are thus controlled automatically. During drilling and during making and breaking of joints, the controlling of the chucks is accomplished by means of the control valve 57 of the rotary motor, and, during introducing of and withdrawing of the drill string, it is effected by means of the control valve 58 of the feed motor.

The chuck 21 may be a power rotated chuck identical with the chuck 27 and axially displaceable by another feed motor. The two chucks 21, 27 are then rotated with diflerent speed when a joint is to be made or broken.

Although a joint breaking means in accordance with the invention has a special advantage for a rock drill of the kind described, the invention is not limited to this application but can be varied in many ways within the scope of the claims.

What I claim is:

1. Drill string joint breaking means in connection with a rock or earth drill, comprising a drill string holder and a rotatable chuck in axial alignment for gripping a drill string and breaking a drill string joint between the holder and the chuck, said chuck being of the kind which is fluid-actuated and grips when loaded by pressurized hydraulic fluid, a hydraulic motor for rotating the chuck, a fluid supply conduit for supplying pressurized hydraulic fluid to the motor and including a control valve, a branch conduit of said supply conduit connected to said chuck for supplying pressurized hydraulic fluid to the chuck so as to actuate the chuck, and a delaying valve in said branch conduit adapted for delaying the supply of pressurized hydraulic fluid to the chuck until the hydraulic motor and thereby the chuck is rotating upon a pressurization of the supply conduit of the motor by means of the control valve.

2. Means according to claim 1 in which said delaying valve comprises a valving member which is biased into a closed position but arranged to move a distance into an open position when acted upon by the pressurized hydraulic fluid when said supply conduit of the rotation motor is pressurized, and means is arranged to moderate the speed of the valving member during this movement to the open position.

3. Means according to claim 2 in which said means for moderating the speed of the valving member comprises a dashpot.

4. Means according to claim 3 in which said valving member has a head moving in a dashpot chamber.

5. Means according to claim 4 in which said head is biased by a spring towards said closed position.

6. Means according to claim 5 in which the dashpot has a one-way passage connected to permit rapid return of the valving member to the closed position.

7. Means according to claim 6 in which said one-way passage is a passage through the head of the valving member.

8. Means according to claim 1 in which said branch conduit is drained through a restricted passage.

9. Means according to claim 1 in which said rotatable chuck is arranged to be axially displaces along a feed bar by means of a feed motor, and said rotation motor is reversible and has an alternative second supply conduit through which it is supplied with pressurized hydraulic fluid during making joints and/or during drilling.

10. Means according to claim 9 in which the control valve, when in a first position, connects the first mentioned supply conduit to a source of pressurized hydraulic fluid and said second supply conduit to drain and, when in a second position, connects the first supply conduit to drain and the second to the source of pressure fluid, said control valve having also a position in which it isolates both the first and the second supply conduits from the source of pressure fluid.

l 1. Means according to claim 10 in which a connection conduit is connected between said second supply conduit and said branch conduit and a one-way valve is arranged in this connection conduit so as to permit flow only in the direction from the second supply conduit to the chuck.

12. A drilling apparatus for rotary drilling, comprising an elongated feed bar, a slide mounted on said feed bar, a feed motor for displacing the slide along the feed 1 bar, a drill string holder at one end of the feed bar, a

pressurized hydraulic fluid, a reversible hydraulic motor for rotating the chuck, a first fluid supply conduit for supplying pressurized hydraulic fluid to the motor so as to effect forward rotation of the motor, a second fluid supply conduit for supplying pressurized hydraulic fluid to the motor so as to effect backward rotation of the motor, a branch conduit of said second supply conduit connected to said chuck for supplying pressurized hydraulic fluid to the chuck so as to actuate the chuck, and a delaying valve in said branch conduit adapted for delaying the supply of pressurized hydraulic fluid to the chuck until the hydraulic motor and thereby the chuck is rotating upon a sudden pressurization of the supply conduit of the motor.

* III a:

Claims

11. Means according to claim 10 in which a connection conduit is connected between said second supply conduit and said branch conduit and a one-way valve is arranged in this connection conduit so as to permit flow only in the direction from the second supply conduit to the chuck.

12. A drilling apparatus for rotary drilling, comprising an elongated feed bar, a slide mounted on said feed bar, a feed motor for displacing the slide along the feed bar, a drill string holder at one end of the feed bar, a rotatable chuck on said slide, said chuck being of the kind which is fluid actuated and grips when loaded by pressurized hydraulic fluid, a reversible hydraulic motor for rotating the chuck, a first fluid supply conduit for supplying pressurized hydraulic fluid to the motor so as to effect forward rotation of the motor, a second fluid supply conduit for supplying pressurized hydraulic fluid to the motor so as to effect backward rotation of the motor, a branch conduit of said second supply conduit connected to said chuck for supplying pressurized hydraulic fluid to the chuck so as to actuate the chuck, and a delaying valve in said branch conduit adapted for delaying the supply of pressurized hydraulic fluid to the chuck until the hydraulic motor and thereby the chuck is rotating upon a sudden pressurization of the supply conduit of the motor.