US1984867A

US1984867A - Core drill

Info

Publication number: US1984867A
Application number: US673125A
Authority: US
Inventors: Charles A Dean
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-02-13
Filing date: 1933-05-26
Publication date: 1934-12-18
Anticipated expiration: 1951-12-18

Description

C. A. DEAN CORE DRILL Dec. 18, 1934.

Original Filed Aug. 25, 1932 Rmwm O@ N .0 m. T. MA n w Hm a ,n

Patented Dec. 184, 1934 Charles A. Dean,

Bakersfield, Calif.

Refiled ior abandoned application No.

` 630,074, August 23,1932.

26, 1933, Serial No. 673,125.

' ar'y 13, 1933 7 Claims.

This invention relates to core drills for earth boring,land more particularly to improvements for lretaining acore sample in drills of the type in which core-gripping elements are inserted and are retracted from a core in positive manner. by

longitudinal play between a core barrel and a portion of-'the drillstem. An illustration of rotary core drill having core grips actuated positively by play of a core barrel is exhibited in Dean Patent 1,850,386. The present invention is applicable broadly to forms of core drill in which longitudinal or vertical play between a drill sub and core barrel alternately projects and retracts core-gripping dogs.

In abstracting a core, the weight of the core barrel with its contentshas been utilized to keep the core barrel suspended in its lowermost position from-the drill sub so that the core-gripping elements will be forced most effectively into the earth sample. However in actual operation varisus conditions intervene to cause the core dogs to be withdrawn sufliciently to score the core sample iriuriously. or until their weakened Agrip permits f .e core to` slide down and be spoiled or be lost entirely. This frequently occurs deep in the earth where conditions are unknown or are difcult to anticil` e, and are practically impossible to alter. Such inadvertent release of the gripping elements results often from the practice of drillers to whip the drill up and down during preparation and withdrawal of the core sample.

An object of this invention is to assure positive gripping by the core-retaining elements during the entire operation of abstracting a core that has been obtained in the drill. A general object of this invention is to keep the core-gripping elements projected firmly into the core once actual withdrawal of the core barrel in the drill hole has been started. It is an object to overcome scoring or inadvertent release of a core even though, for example, the drill lbe dropped or be rested on some obstruction in the drill hole; yet another object is to provide positive core-locking means that will not interfere with repeated raising and lowering of the drill during actual core cutting. It is an object to provide core locking means that will secure the core-gripping dogs effectively in various positions or degrees of penetration of the core.

A further object of this invention is to provide a core locking structure that is applicable tordiffering drills of the general ltype described;v one that does not interfere with normal passage of slushing fluid through the drill, and is positive in action but simple in structure. Another object This application May In Canada Febru- (Cl. Z55-72) is 4to provide core locking means that, while economical to manufacture andto maintain under eld conditions, will permit the use of a variety of actual locking elements. Other objects will appear with the following description of illustrative 5 lembodiments of this invention, as 'shown in the accompanying drawing.

`Referring to the drawing,

Fig.' 1 shows in vertical section a core drill embodying one form of this invention; and

Fig. 2 shows in vertical section a modified locking structure embodying this invention; and

Fig. 3 shows in horizontal section along the plane III-III of Fig. 1 a particular form of mounting of core dogs and core container for l5 use with this invention.

Figs. 4, 5, and 6 illustrate particular modications of this core-container locking means combiriation.A

Referring more particularly to the drawing, Fig. 1 illustrates a core drill comprising a drill stem lv having a central bore 2.; The stem is connected to a drill sub that comprises an outer core barrel 3 and reamer blades 4. An inner core barrel 5 is mounted with splined connection for 2 5 longitudinal play within the outer barrel. Core dogs 6 are seated between the inner and outer barrels so as to be projected into a core when the inner barrel moves down within the outer barrel, and to be withdrawn from the core by rela- 30 tive zupward movement of the inner barrel, as

' when the drill rests on the bottom of the drill hole. Between the inner and outer barrels is space communicating with the bore oi' the drill stem for ilow of the flushing iluid usually supplied to the cutters. Y

-As shown, the bore of the drill' stem terminates in an enlarged cavity above the inner core barrel. 'lhe upper walls of the cavity expand downwardly by successive stepped enlargements I of the bore 40 or the drill stem. The top portion 8 of the inner core barre'. is somewhat concave. Thus structure is provided for retaining 4or wedging a spacing element, as bar 9, to minimize play or telescoping between the inner core barrel and the drill stem. Before'a core is.elevated, locking element or bar 9 is dropped through the drill stem, usually along with heavy slushing fluid, until that element rests on top of the inner core barrel and against the shoulders 'I at the bottom of the drill stem bor/e; 50 In this way', during elevation of a core, the inner barrel is held in some relatively lower ,y tion to prevent the core dogs 6 from being irom the core even though the drill be dropped against an obstruction. Further, this structure permits the dogs to work more deeply into a core.

Modications are contemplated in this form of the invention. For example, as illustrated in Figs. 4 and 5, the upper cavity walls may be roughened or grooved instead of containing the distinct shoulders 7. Similarly the top of the inner core barrel may be modified. Also the single bar may be multiplied as in Fig. 4 element 20, or extended even to form a. more or less conical locking member as in Fig. 5-element 21.

An alternative embodiment of this invention is illustrated in Fig. 2, in that a spheroidal locking element 10 is engageable in the cavity between the drill stem and the inner core barrel. The upper Walls of the cavity may flare simply, as shown, or may comprise pronounced shoulders. Also Fig. 2 illustrates a modification of the top portion of the inner core barrel, having shoulder 11 and having a contracted top 12 that is spaced from the walls of the outer barrel sufhciently to permit a ball 10 to pass down to shoulder 11. Thus the ball may wedge to provide locking engagement against any tendency of the inner barrel to rise within the stem. In this way the coregripping elements are held in a core. With the top of the inner core barrel modified as shown, it is contemplated that an elongate locking member may be used, such as a wedge-shaped bar or chunk as in Fig. 6 element 22. l

The locking structure of this invention is exceedingly simple, so as to promote satisfactory core sampling even under the requirements of practical operations in varied formations and in out-of-the-Way localities. AMoreover, when the core is to be Withdrawn there is provided positive locking of the core-gripping elements. Nevertheless there is no interference with continued flow of slushing uid.

This invention has been illustrated with reference to a particular, simple form of core drill. However other forms of core drill are available in common use. Nevertheless the principles of this invention are applicable to provide a simple structure for preventing play of a core barrel within an outer barrel during abstraction of the core or for preventing withdrawal of core-retaining elements on dropping of the core container during abstraction or during severing of the core.

In accordance with the patent statutes, illustrative embodiments and preferred operation of this invention have been described, but the invention is not limited thereto, Within the appended claims except as limited by the prior art.

This present application comprises the subjectmatter of my former application Ser. No. 630,074.

What is claimed is:

1. A core drill comprising a tubular drill stem and a depending drill sub, a core container mounted for longitudinal play within the sub, core-gripping elements mounted to be engaged by the drill sub for penetration into a core and retraction therefrom respectively on raising and lowering of the drill sub relatively to the core container, and means within the drill to lock the core-gripping elements against retraction at different relative positions 'of drill sub and container.

2. A core drill comprising a tubular drill stem and depending drill sub, a core container ,mounted for longitudinal play within the sub and terminating .in a core cutter projecting below the sub, core-gripping elements mounted for engagement by the sub to be'retracted on relative upward-movement of the container, va cavity between the drill stem and the core container, and means operative within the cavity at substantially any relatively lower position of the core container to limit said longitudinal play and lock I the core-gripping elements against retraction.

3. A core drill comprising a drill stem having a central bore, a drill sub depending therefrom, a tubular core container mounted for longitudinal movement relatively to the sub, and coreretaining elements mounted for insertion and retraction by said relative movement, the upper portion of the core container and the walls of the r drill stemabove the core container being adapted to grip a relatively large object receivable through the drill stem to limit said relative movement and lock the core-retaining elements against retraction.

4. A core drill comprising a drill stem having a central bore, a tubular drill sub, a corecontainer mounted for vertical play Within the sub and terminating in a core cutter projecting below the sub, and core-gripping elements mounted for engagement by the sub to be retracted on relative upward movement of the container, the bore of the drill stem being enlarged above the core z container to receive a wedging element and, 'with the upper portion of the core container, conforming to wedge said element against the drill stem for preventing play of the container and retraction of the core-gripping elements.

5. A core drill comprising a drill stem having a central bore, a tubular drill sub, a core container mounted for vertical play in the sub, and core-retaining elements mounted for insertion and retraction by said play, the walls of the drill stern bore receding in a step conformation to form a space above the core container, and the top of the core containerbeing adapted to wedge an elongate object against the' stepped walls to limit play and lock the core-retaining elements against retraction.

6. A core drill comprising a drill stem having a central bore, a tubular drill sub, a core container mounted for Vertical play in the sub, and coreretain'ing elements mounted for insertion and retraction by saidv play, the walls of the drill stem bore being enlarged downwardly to form a space above the core container, and the top portion of the core container being concave inwardly to wedge a relatively large object in lthe space for limiting play and locking the core-retaining elements against retraction.

'7. A core drill comprising a tubular drill stem, a drill sub having a core container mounted for vertical play therein, and core-gripping elements adapted to be inserted andsretracted by the drill sub in said play, the top portion of the core container and the walls of the drill bore together forming a cavity adapted to receivea wedging object from the drill stem, with walls to retain the object for wedging the container downwardly in the drill stem to lock the core-gripping elements against retraction.

CHARLES A. DEAN.