US2522399A - Core drill - Google Patents

Description

A. F. PICKARD sept. 12, 195o coRE DRILL Filed Nov. .15, 194e FIG. 2,

I INVENTOR. l ALBERT f.' P/CKARD BY S MM m ATTORNEYS Patented Sept. 12, 1950 E. J. Longyear Company, Minneapolis, Minn., a corporation of Delaware y Application November 15, 1948,1S'erial No. 60,093

invention relates to core barrels used with core drills, particularly of the type used for exploratory drilling, and more especially toimprovements in core lifters for such core barrels.

In, the art of core drilling the bit, reaming shell,

core barrel outergand inner tubes, core lifter and couplings, by which the assembly is attached to the-drill rods are collectively known as the core barrel.

In the core drilling art it has been common practice to provide a core barrel with a core barrel inner tube for receivingthe core as itis produced by the drill. As originally made such barrels had 5 claims. (o1. s55-72)' ing a strong core formation. As a result, journals andthe lcore'barrel inner tubes have been brokenv whenattempts are 'made to withdraw the corel barrelA and the core, when using such mechanismo.` Also, the core barrel inner tube is of thin metal and itis difficult to machine threads into thev end of it. Hence,fattempts to mount the core lifter on the core barrel inner tube have necessitated la thickening of the inner tube or, con-` versely, acceptance of a weak inner tube structure;

It is an object of the present invention to provide an improvedA core barrel wherein the forethe core barrel inner tubemounted so as to rotate with the outer tube, but these were'subject to objection because the rotating core barrel inner tube tended to iamor drag upon thecore as it was produced, and `inmany instances caused the core to be disintegrated, thus destroyingor limiting the usefulness of the mechanismfor exploratory work; v

Morezlately, it has been Athe practice to mount n the `core barrelinner tube upon journals so that theoorebarrel inner tube' is free to -receive the 25 The-"eiect is that the core barrel innerr tube, as]v core Vas it fis. produced, without itself rotating.

it drags slightly upon the core, is thereby stopped from rotating, the outer tubeoi the'assembly inl I'the-'meantime being free to rotate aboutfthe core barrel inner tube as the entire mechanism progressed into the formation being'drilled.

For the purposeof breakingloose the core when thecorebarrel inner tubeis filled, it has been customary to provide what 'is known as a core lifter in the core barrel assembly. This is usualgoing disadvantages are obviated and more particularly to provide an improved core I ca-rre'ly wherein the core lifter is-mounted in such a manner that during the drilling operation 'itis carried by andassumes a position on the lower end of lthe core barrel inner tube and accordingly has a non-rotating action during this portion ofv its "operation, but is mounted so as to transfer v thejloadingimposed by breaking and lifting the corejto the bit during the core breakingand withdrawing function.

It is also an object of the inventionL to provide an improved core barrel'wherein the core lifter is mounted'within a. transfer case slidable upon the core barrel inner tube and movable relative thereto into Vabutment with the bit for breaking and ,lifting the core.

It isa further object of the invention to provide an improved core barrel capable of eXtractl ing amuch larger percentage of core than. vhas ly in the form" of -a small split ring having an exy y terior tapered or conicalsurface which bears upon'a'corresponding surface of thedrill bit and an interior surface for gripping the core thereby to break vthe core when the core barrel is withdrawn.

most instances the core lifter has been* mounted in a'recess in thebit itself, but such a method vvof mounting has been subject to disadvantages because the rotating bit tends to rotate the core lifter, andas a; result the core `lifter Wears the core and tends to disintegratejit. In other yinstances, attemptshave been made to` mount the core lifter upon the core barrel inner `tube, 'when the latter is journalled, so as thereby to provide Vnon-rotation of the core lifter as thecorebarrel progresses forward: over the core.

The difficulty with such constructions has been that the core barrel inner tube',` and particularly f its-journal mounting, are not suiiiciently strong` to prov-ide the tension force vnecessary for break# been possible Vwithvprei/ious apparatus. 4

It is also an object of the inventionwto provid an .improved core barrel o f rugged and simple construction, yethaving improved,functioning characteristics.

Other and vfurther objects o f the invention. are

' those inherent inv the apparatus hereinA illustrated,

describedr and claimed. f

The invention is illustrated with reference Vto the drawings wherein ,Figure 1 is a longitudinal view, partly in sectien, of the core barrel of the present invention. showing it during the period `of. drilling;

\ Figure 2 is a. fragmentarylongitudinal sectional view vof the core lifter portion and bit end of the .apparatusishown in Figure land showing the .apparatus during the core lifting operation;

' Figure 3 isa longitudinal sectional view some#A what'enlarge'd' las compared to Figures 1 and 2,

showing the transfer case separated from the "remaining portions of the apparatus;

Figure 4 is a longitudinal sectional view of the core lifter which operates in conjunction with the' transfer case of Figure 3, likewise shown separated from the remaining portions of the apparatus;

Figure 5 is a longitudinal sectional view of a modified form of core lifter for soft cores, which also may be used in the transfer case of Figure 3, in place of the core lifter of Figure 4;

Referring to the drawings III illustrates the earth or rock formation through which the drill is being penetrated for producing a core I I of the formation. The core barrel includes a coupling i2 which is provided at its upper end with standard threads I3 for receiving the lower coupling of the drill rods to which it is attached. The coupling I2 is bored to receive an inner member 8 which is press iitted into the coupling I2 and additionally pinned at 9 to provide a solid connection. The member 8 is provided with a channel at, I5 which terminates at the space I6 so as to allow the drilling fluid to travel in the direction ofarrows I 1 for cooling the bit, and the coupling I2 and member 8 are side drilled at 1 to provide a relief port extending into the center bore 6. The member 8 is provided witha screwed in tubular Yjournal stud IS which is threaded into the member 8 and provided at its lower end with a portion IS of reduced diameter. Upon the portionsy I8 and i9 there is journalled the journal block of the core barrel inner tubeV 21. The journal block 2U is held between the bearing washers 2i and 22 and is retained in place by means of the castellated nut 23, the latter being adjusted andheld by cotter pin 24. rlhe member 20 is provided with threads at A so as to receive the upperl threaded end of the core barrel inner tube 21. As a consequence of this 'construction the core barrel inner tuben21 and journal block 20 are free to rotate as a unitrelative to the stud IS-I 9, or stated conversely, the core barrel inner tube 21 can remain stationary and slide down upon the' core while the outer tube 3|, reaming shellv 33 which likewise is threaded at its lower end 34 to receive the bit 35. Consequently, Vas the coupling I2 is rotated during the drilling'operation, core barrel outer tube, reaming shell 33 and bit 35 are likewise rotated.' The lower surface of the bit 35 and the outer surface of the reaming shell 33 are provided with linset diamonds, bort, stellite or other hard cutting material, and consequently as the'unit is rotated, the bit 35 gradually drills in to the surface 31 and the bit forms the core I I. Meanwhile' the core barrel inner t'ube 21 drags upon'the core II and consequently it is held from rotation, this being permitted by the journalling action on the journal stud I8-I9. l v

The lower end of the core barrel inner tube 21 is provided with a, female shoulder at 38 into which there projects the correspondingly sized male end i The lower end of member 40, which is actually the lower end of the core barrel inner tube, has a male portion 4I of reduced diameter upon which the correspondingly sized female portion 42 of the transfer case, generally designated 43, is adapted to slide longitudinally. Referring to Figure 3 it will be noted that the transfer case 43 has a uniform outer diameter 45 and anupper cylindrical portion 44 of uniform diameter. At the lower end of the transfer case there is an internally tapered conical surface 4B, the two surfaces 44 and 46 being separated by an internally extending flange 41. The lower edge 48 of the transfer case is provided with a plurality of notches 49 across which the drilling fluid may pass so as to allow the drilling fluid to drain when the drill string is lifted.

Referring to Figure 4 there is illustrated a core lifter generally designated 5U having an internal longitudinally iiuted surface 5I and an outer surface 52 of tapered conical configuration adapted to nt and slide upon the be wedged to smallerl diameter by the internal conical surface 4B of the transfer case. The core lifter 50 has a split at 54 so as to permit it to assume a shape of smaller diameter, as is common practice. f

Referring to'Figure I, during-the drilling operation the transfer case 43 which contains the core lifter 55 moves relatively upwardly as a"unit.i

This movement is due to the, fact that the core lifter 50 slightly grips upon the core I I and hence` as .the outer tube, bit and reaming shell gradually move downwardly, the core lifter 5i) tends todrag upon the core II and tends to push against the under surface of the flange 41 of the transfer case, thereby likewise causing the transfer case to drag upon the core. Since the core barrel inner tube, although not rotating, still moves axially with the outer tube, the lower end 4I of the corebarrel :inner tube slides in the female portion 42 of the transfer case until the lower end of the core barrel inner tube abuts against the upper surface of flange 41. Thereupon, the transfer case 43 and core lifter 5E] are moved downwardly as a unit. v4upon the core I I but` neitherrotates and the inner stopped and a lifting force is applied thereto. f The first action is to lift the bit 35 olf the bottom f of thehole, as shown inFigure 2, and then as the bit is withdrawn the inner shoulder 58 of the bit 35 comes into contactwith the lower'surface 48 of the transfer case-which in the meantime has remained stationary due to its drag upon the core. As the drill string and bit 35 was lifted,

this likewise lifted the core barrel inner tube 21 and the transfer case-43,being retainedvby the gripping action of the core lifter V455, hence slidesY relative to the lower end of the `core barrel inner tube at the juncti0n4I-4v2. l Asadditional lifting i force is applied on the Vbit the transfer case vis lifted upwardly, the core lifter 50 in the meantime being held by its grip upon the core.

side the core lifter 50 thereby contracts the ,core

lifter due to the wedging action of the cooperating When a suflicientlifting force has thus been applied to the core III:`

conical surfaces 48 and 52.

The ,rela-` tive movement of the transfer case upwardly outit is broken off as illustrated at 60 and the entire core barrel and drill string is then withdrawn and removed from the hole.

When the core barrel is used in very soft formations, such as clay, the core lifter 58 of Figure 4 may be replaced by the core lifter assembly l0 of Figure 5, wherein the ring "il is flexible and is split at l2. The outer surface of the ring 'H is tapered at i3 to correspond to the taper 46 of the transfer case 43, but the inner surface of 'H notched at its upper edge to receive a plurality of flexible inwardly bent fingers 75 which are firmly attached to the ring 'H by rivets 7'5. The

Li. In a core barrel having an outer tube provided with a reaming shell and terminating in an entire assembly 'i0 fits into the transfer case 43 and operates like the core lifter 50 in that while' drilling is proceeding, it remains stationary and hugs the core as the latter is produced, meanwhile forcing the transfer case relatively upwardly against the core barrel inner tube as in Figure l. When the core barrel is withdrawn the g transfer case is lifted by contact with surface 58 ments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments herein.

What I claim is:

l.' In a core barrel having an annular drill bit and having an inner tube journalled within the drill string, said inner tube terminating in spaced relation to the bit for receiving the core as it is produced, the improvement comprising a slidable tubular transfer case shaped to slide axially upon that portion of the inner tube which is most adjacent the bit and having an axial length such that it is free to move axially between the bit and adjacent end of the inner tube, said case being shaped so as to abut against the bit when moved axially toward the bit and abut against a part of the inner tube when moved axially toward the inner tube so as thereby to have only a limited range of axial movement, said case having a tapered inner surface between the end of the inner tube and the bit, and a split core lifter ring having .an inner surface for engaging the core :and a annularv drill bit and having a core barrel inner tube of lesser diameter than the outer tube, journalled at one end in the outer tube land having a free end, the improvement comprising having the core barrel inner tube of a length such that a space is provided between the free end of the core barrel inner tube and the drill bit, and a cylindrical transfer case of approximately the same diameter as the core barrel inner tube fitted to the free end of the inner tube for limited axial sliding movement thereon and having an axial length such that it is free to move between the bit and the adjacent end of the inner tube, said transfer case being free to rotate with respect to the core barrel inner tube, said transfer case having ay tapered conical inner surface and a split core lifter ring having a conical external surface tted to slide within and be contacted by the tapered conical inner surface of the transfer case, said core lifter ring and transfer case being axially slidable as an assembly on the ycore barrel inner tube from a position spaced from the bit to a position in abutment with the bit.

5. The apparatus of claim 4 further characterized in that the core barrel inner tube slides within a portion of the transfer case and said transfer case has a flange on its inner surface to serve as a stop for said sliding movement and as a stop for the sliding movement of the split lifter ring therein.

ALBERT F. PICKARD.

REFERENCES CITED f The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,720,700 Stone July 16, 1929 1,883,321 Allen Oct. 18, 1932 2,066,625 Howard et al Jan. 5, 1937

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