US3592275A

US3592275A - Spring loaded adapter for drill rods and core barrel

Info

Publication number: US3592275A
Application number: US815377A
Authority: US
Inventors: Ernest P Fletcher; William L Acker
Original assignee: Acker Drill Co Inc
Current assignee: Acker Drill Co Inc
Priority date: 1969-04-11
Filing date: 1969-04-11
Publication date: 1971-07-13
Anticipated expiration: 1988-07-13

Abstract

An adapter for connecting a core barrel to drill rods to provide automatic water control to a diamond drill bit and to provide cushioning pressure control to the diamond drill bit. An elongated hollow body has an internally threaded upper end to receive a hollow drill rod, a series of drill holes are spaced about an axial pocket and lead from the discharge of the hollow drill rod to a water chamber. A floating hollow piston has a threaded lower end for coupling to the top of a core barrel. Above the threaded lower end of the piston is an enlarged splined portion received in a housing that has internally longitudinal grooves for receiving the splines on the piston or vice versa and is threadedly connected to the lower end of the elongated hollow body. A spiral spring is received over a reduced portion of the hollow piston about its splined portion and extends up into an axial pocket in the elongated hollow body where its upper end rides against annular shims. The upper end of the reduced portion of the hollow piston is closed off and spaced below the upper end are radial ports that communicate with the water chamber when the hollow piston is extended by action of the spring. Spaced below the upper portholes are axially spaced ports which communicate with the water chamber when the hollow piston is retracted against the spring at which time the upper portholes are closed off. The first-mentioned set of portholes are so axially spaced from the second set that all water flow is cut off to the hollow floating connecting piston for a certain part of its axial positioning as when the core drill reaches a soft strata.

Description

United States Patent [72] inventors Ernest P. Fletcher Athens, Greece; William L. Aclter; Scranton, Pa. [21 Appl. No 815,377 [221 Filed Apr. ll, 1969 [45] Patented July 13, I971 [73] Assignee Aelter Drill Company, Inc.

Clarks Summit. Pa.

[54] SPRING LOADED ADAPTER FOR DRILL RODS Primary ExaminerStephen J. Novosad Attorney-Jones and Lockwood ABSTRACT: An adapter for connecting a core barrel to drill rods to provide automatic water control to a diamond drill bit and to provide cushioning pressure control to the diamond drill bit. An elongated hollow body has an internally threaded upper end to receive a hollow drill rod, a series of drill holes are spaced about an axial pocket and lead from the discharge of the hollow drill rod to a water chamber. A floating hollow piston has a threaded lower end for coupling to the top of a core barrel. Above the threaded lower end of the piston is an enlarged splined portion received in a housing that has internally longitudinal grooves for receiving the splines on the piston or vice versa and is threadedly connected to the lower end of the elongated hollow body. A spiral spring is received over a reduced portion of the hollow piston about its splined portion and extends up into an axial pocket in the elongated hollow body where its upper end rides against annular shims. The upper end of the reduced portion of the hollow piston is closed off and spaced below the upper end are radial ports that communicate with the water chamber when the hollow piston is extended by action of the spring. Spaced below the upper portholes are axially spaced ports which communicate with the water chamber when the hollow piston is retracted against the spring at which time the upper portholes are closed off. The first-mentioned set of portholes are so axially spaced from the second set that all water flow is cut off to the hollow floating connecting piston for a certain part of its axial positioning as when the core drill reaches a soft strata.

SPRING LOADED ADAPTER FOR DRILL RODS AND CORE BARREL Drilling a hole is at times very difficult since the drill opera tor really has only three elements that he can control:

1. The rotational speed of the drill string 2. Pressure applied 3. Amount of water or cutting fluid introduced This problem is further complicated by the fact that many holes are quite deep, over L000 ft., and that the various strata encountered may be completely unknown. By the time the driller is alerted to the change in strata, either by color of return water or by difference in sound of the laboring drill engine, it is already too late for him to cope with some emergency.

ln obtaining a high percentage of core recovery from soft or friable foundations, the drillers procedure is to cut back on circulating water to prevent excessive water erosion and to cut back on feed pressure to allow the bit to slowly work its way through the soft and broken area.

In practice, what happens is that the driller suddenly breaks into an ore zone, usually without warning and before he can make the necessary adjustments, part of the core had already been lost. Sofl coal veins are generally overlain with a hard sandstone and the driller is proceeding apace only to suddenly break through to the soft coal and wash half of the vein before he can cutback on fluid flow. The same is true in copper ores, which may be in lenses, are easily eroded, and occur without any warning.

By this invention, it is proposed to incorporate a springloaded section, sub or coupler in the very top of the core barrel. In this sub is a pilot valve that opens and closes according to pressure applied.

As the core barrel with sub attached is entering the hole, the pilot valve is fully extended and full fluid flow is obtained through the center opening. It is very desirable to have this full fluid flow under no pressure to clean out cuttings that may have settled in the bottom of the hole.

When drilling resumes under normal conditions, full pressure is applied to bit, the pilot bit is all of the way retracted. and full fluid flow is again obtained through a second set of ports that are spaced below a first and upper set of port holes that serve when there is no pressure on the drill bit.

When a breakthrough to a soft area occurs, however, the spring-loaded feature of the coupler allows the pilot valve to advance and immediately cut down on water flow thus preventing what would be abnormal erosion.

This sequence of events in the use of this spring-loaded sec tion, sub or coupler provides a number of advantages:

1. Core washing is prevented by the immediate reduction of flow.

2. The resultant increase of water pressure at the top of the hole alerts the driller to what is happening.

3. The cushioning effect of the spring loading relieves shock on the diamond bit and improves bit life.

4. The combination of one and two of above will be auto matic and instantaneous.

For a more complete understanding of the invention, reference is had to the drawings, the description which follows and the claims. In the drawings,

FIG. I is a cross-sectional view of the coupling connecting a section of drill string at its top with the top of a core sample therebelow with the coupling having its piston extended;

FIG. 2 is a cross-sectional view like FIG. I, but with the piston of the coupling retracted; and

FIG. 3 is a sectional view along line 3-3 of FIG. 1.

Throughout the description, like reference numbers refer to similar parts.

A coupling assembly is generally indicated 10. It is made up of an elongated body 11 having an axial bore 12 and an elongated piston 25 having an axial bore 26. An upper threaded end 13 on the elongated hollow member connects with the lower section of a drill string D. A lower end of the piston having a bore is threaded and connects with the upper end of a core sampler CS.

The elongated body 11 has a transverse partition 14 separating the upper bore portion at the upper threaded and I3 from the bore portion therebelow. Spaced below this partition 14 is an enlarged in diameter water chamber 15 in the bore 12. The bottom or floor 15a of the water chamber 15 is inclined to the horizontal to cooperate with lower ports 34 in the piston as will be explained. Axially extending drill holes or passageways 20 connect the bore 12 above the partition 14 with the water chamber 15. Spaced below the floor 15a of the water chamber is an O-ring seal 16 about the piston rod upper end portion 31v Spaced further below the water chamber floor 15a and the O-ring seal 16 is an intermediate enlarged bore portion 17 in the body 11. A threaded lower end portion 18 receives the threads 19a of a sleeve 19 having an inturned annular end at 1% and axially extending splines 19c.

Received with the axial bore 12 ofthe elongated member 1] is an elongated piston generally indicated at 25 that has an axially extending bore 26. The upper end of the piston 25 is closed offat 27 and has a threaded lower end 28 that connects with an upper end of a core sampler CS.

Above the threaded lower end 28 of the piston 25 is an enlarged guide portion 29 that rides within the inturned annular flange 19b. Above the guide portion 29 is an enlarged in diameter collar portion 30 having axially extending grooves 300 that receive the splines [DC on the surrounding sleeve 19. An upper end portion 31 of the piston with its bore 26 extends from the collar 19 up through the intermediate portion l7 of the elongated body member, through the O-ring seal and bore portion 12 of the elongated body, through the water chamber 15 and into the upper surrounding portion of bore 12.

The upper end portion 31 of the piston 25 has an upper set of radially extending port holes 33 which communicate with the interior bore 26. Spaced below the upper set of bore holes 33 is a lower set of portholes 347 These portholes 34 are positioned on an incline to the horizontal in the same general direction as the inclined bottom 15a of the water chamber 15 but at a greater angle of incline.

Surrounding the piston portion 31 and located in the surrounding intermediate chamber 17 of the elongated body 11 is a spiral compression spring 36 whose lower end presses against the collar 30 and its upper end presses against annular shims 37 about the piston rod portion 31 and the shims press against the upper end of the chamber 17. The spring 36 serves to apply a downwardly biasing force on the elongated piston 25. The shims 37 provide for adjustment ofthis force.

In FIG. I where the piston 25 is in its extended and lower position the upper set of port holes 33 are in communication with the water chamber 15. They receive drilling fluid from the drill string thereabove which passes through the upper end of bore 12 in the elongated body down through the drill holes or axially extending passageways 20 leading to the top of the water chamber 15. From the water chamber IS the fluid passes through the port holes 33 to the bore 26 of the elongated piston 25 and on downward to the core sampler CS. This is the position of the sub or coupler when the core barrel enters the hole. The pilot valve (upper port holes 33 and lower portholes 34) is fully extended and full fluid flow is obtained through the central bore. It is very desirable to have this full fluid flow under no pressure applied through the sub to the drill to cleanout cuttings that may have settled in the bottom of the hole.

In FIG. 2, drilling has resumed under normal conditions, full pressure is applied to the bit, the pilot bit and piston is all of the way retracted, and full fluid flow is again obtained through certain of the lower set of portholes 34 that are now in communication with the water chamber 15. When a breakthrough to a soft area occurs, however, the spring-loaded feature of the sub or coupler allows the pilot valve to advance, i.e., the piston with the lower portholes 34 moves downwardly, and immediately the portholes 34 are blanked off within the bore wall therebelow of the surrounded elongated body portion and the drilling fluid flow is cut down thus preventing what would be abnormal erosion of the core sample.

This sub or coupler provides for an automatic operation to carry out its many highly advantageous functions yet is relu tively simple in construction and is highly reliable.

We claim as our invention:

1. A coupler for connecting a drill rod in a core drilling string to a core barrel comprising, in combination.

an elongated body having an axial bore, a threaded upper end portion for coupling to a hollow drill rod, a transverse partition separating the upper hollow end portion adjacent the threaded portion from the rest of the bore therebelow, a water chamber communicating with said bore and spaced below the transverse partition, passageway means connecting the bore above the trans verse partition with the water chamber, an intermediate bore portion spaced below the water chamber and having an enlarged diameter greater than the axial bore portion thereabove and a lower end bore portion in communication with the intermediate bore portion;

an elongated piston member having an axial bore and received at its upper end in the axial bore of the elongated body below its transverse partition and having a threaded lower end extending below the lower end of the elongated body member for connecting with a core barrel, an enlarged collar portion received in said lower end bore portion of the elongated body, an upper elongated portion above the collar portion and of a reduced diameter extending upwardly through said intermediate bore portion of the elongated body, the bore portion of the elongated body thereabove, the water chamber and into the bore portion of the elongated body above the water chamber for telescope movement;

means on the lower end of said elongated body retaining the elongated piston therewithin',

said elongated piston having its upper end closed oft" and upper porthole means spaced closely adjacent the upper end and extending from the bore to the outside thereby providing communication with the surrounding water chamber when the piston is extended downward and lower porthole means spaced below said upper porthole means and extending from the bore to the outside thereby providing communication with the surrounding intermediate bore portion when the piston is extended downward;

spring means extending within said intermediate bore and connecting lower end bore portions of the elongated member and pressing at its lower end against said collar on the piston and at its upper end against the upper end of the intermediate bore portion and biasing the piston in its downwardly extended position whereby upon application of downward pressure on said elongated body as when drilling, said spring means is compressed and said elongated piston retracts upwardly within the bore of the elongated body, said upper port hole means being closed off and said lower porthole means being in communica tion with said water chamber, the intermediate position of said piston within said elongated bore cutting down com munication between the water chamber and the axial bore of the piston thereby reducing and cutting off the flow of drilling fluid as when a coring drill strikes a relatively soft area and thereby immediately increasing the water pressure to alert the driller.

2. A coupler according to claim 1 including seal means in said elongated body at its bore portion spaced below the water chamber and about the adjacent piston rod potion.

3. A coupler according to claim 2 wherein the threaded portion at the upper end of the elongated body member is internal in the axial bore and the threads of the threaded lower end of the piston are external 4. A coupler according to claim 3 having shim means at the upper end of said spring in said intermediate bore portion of the elongated body for regulating the spring-biasing pressure on said piston.

5, A coupler according to claim 1 wherein said water chamber is an enlargement in the axial bore of the elongated member having a greater diameter and having its bottom end inclined to the horizontal, said lower porthole means in the piston comprise a series of holes along a line inclined to the horizontal at a greater angle than said bottom end ofthe water chamber and in the same general direction, said elongated body member having as its lower end portion a sleeve threadedly attached at its upper end to the elongated body member and defining said lower end bore portion within which said enlarged collar portion on the piston reeiprocates, said means on the lower end of said elongated body retaining the elongated piston being an inturned annular flange on the lower end of said sleeve, said enlarged collar on the piston and said sleeve surrounding the same having borewise extending spline means whereby the piston rod may be rotatably positioned to orient certain of said selected lower series of portholes with respect to the inclined bottom of said water chamber in the elongated body.

6. A coupler according to claim 5 including seal means in said elongated body at its bore portion spaced below the water chamber and about the adjacent piston rod portion.

Patent No. 3,592, 275 Dated July 13, 1971 Inventor(s) ERNEST P. FLETCHER and WILLIAM L. ACKER or appears in the above-identified patent It is certified that err rented as shown below:

and that said Letters Patent are hereby cor Column 4, line 18, cancel "potion" and insert portion Column 4, line 19, after "'claim"cancel "2"and insert 1 Signed and sealed this 21 st day of December 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Acting Commissioner of Patents Attesting Officer

Claims

1. A coupler for connecting a drill rod in a core drilling string to a core barrel comprising, in combination, an elongated body having an axial bore, a threaded upper end portion for coupling to a hollow drill rod, a transverse partition separating the upper hollow end portion adjacent the threaded portion from the rest of the bore therebelow, a water chamber communicating with said bore and spaced below the transverse partition, passageway means connecting the bore above the transverse partition with the water chamber, an intermediate bore portion spaced below the water chamber and having an enlarged diameter greater than the axial bore portion thereabove and a lower end bore portion in communication with the intermediate bore portion; an elongated piston member having an axial bore and received at its upper end in the axial bore of the elongated body below its transverse partition and having a threaded lower end extending below the lower end of the elongated body member for connecting with a core barrel, an enlarged collar portion received in said lower end bore portion of the elongated body, an upper elongated portion abovE the collar portion and of a reduced diameter extending upwardly through said intermediate bore portion of the elongated body, the bore portion of the elongated body thereabove, the water chamber and into the bore portion of the elongated body above the water chamber for telescope movement; means on the lower end of said elongated body retaining the elongated piston therewithin; said elongated piston having its upper end closed off and upper porthole means spaced closely adjacent the upper end and extending from the bore to the outside thereby providing communication with the surrounding water chamber when the piston is extended downward and lower porthole means spaced below said upper porthole means and extending from the bore to the outside thereby providing communication with the surrounding intermediate bore portion when the piston is extended downward; spring means extending within said intermediate bore and connecting lower end bore portions of the elongated member and pressing at its lower end against said collar on the piston and at its upper end against the upper end of the intermediate bore portion and biasing the piston in its downwardly extended position whereby upon application of downward pressure on said elongated body as when drilling, said spring means is compressed and said elongated piston retracts upwardly within the bore of the elongated body, said upper port hole means being closed off and said lower porthole means being in communication with said water chamber, the intermediate position of said piston within said elongated bore cutting down communication between the water chamber and the axial bore of the piston thereby reducing and cutting off the flow of drilling fluid as when a coring drill strikes a relatively soft area and thereby immediately increasing the water pressure to alert the driller.

3. A coupler according to claim 2 wherein the threaded portion at the upper end of the elongated body member is internal in the axial bore and the threads of the threaded lower end of the piston are external.

4. A coupler according to claim 3 having shim means at the upper end of said spring in said intermediate bore portion of the elongated body for regulating the spring-biasing pressure on said piston.

5. A coupler according to claim 1 wherein said water chamber is an enlargement in the axial bore of the elongated member having a greater diameter and having its bottom end inclined to the horizontal, said lower porthole means in the piston comprise a series of holes along a line inclined to the horizontal at a greater angle than said bottom end of the water chamber and in the same general direction, said elongated body member having as its lower end portion a sleeve threadedly attached at its upper end to the elongated body member and defining said lower end bore portion within which said enlarged collar portion on the piston reciprocates, said means on the lower end of said elongated body retaining the elongated piston being an inturned annular flange on the lower end of said sleeve, said enlarged collar on the piston and said sleeve surrounding the same having borewise extending spline means whereby the piston rod may be rotatably positioned to orient certain of said selected lower series of portholes with respect to the inclined bottom of said water chamber in the elongated body.