US1765513A - Core catcher - Google Patents

Description

June 24, 1930. 1.. H. WELLENSIEK CORE CATCHER Filed April 12, 1928 'the core engaging means.

Patented June 24, 1930 UNITED STATES PATENT OFFICE LOUIS H. WELLENSIEK, F HOUSTON, TEXAS, ASSIGNOR TO I-IlIl'GHlElS.TOOL COMPANY, OF HOUSTON, TEXAS, A CORPORATION OF TEXAS CORE CATCHER Application filed April 12,

My invention relates to core catchers em ployed on well-drilling core bits.

It is an object of the invention to provide a core catcher, particularly adapted for use in hard formation, and formed to effectively engage the core along the full forward faces of the core gripping devices.

It is my aim to provide a core gripping device which will be retained out of engage ment with the core while the drilling operation is in progress, but which will be moved into engaging position when the core drill is moved upwardly.

It is desired to provide core-gripping jaws supported by resilient flexible arms allowing free movement of the said jaws.

Referring to the drawing herewith, Fig. 1 is a central longitudinal section through a core drill showing my device in place therein, said device being in side elevation.

Fig. 2 is a fragmentary top plan view of the device removed.

Fig. 3 is a central vertical section through my device.

Fig. 4 is a fragmentary sectional view, illustrating the core-engaging position of the aws.

J In illustrating my device, I have shown it in position within a hard formation core drill, having a head 1 with rolling cutters 2 mounted upon shafts 3 welded in position within the head. Said cutters are mounted so that some cutters will engage the inner side of an annular hole and the others will engage the outer side of said hole.

The head is connected with a tubular nipple 4, having an upper socket 5 for engagement with a drill collar 6, and a lower socket 7 of smaller diameter to receive the lower head 8 of the core barrel 9. Below the socket 7 the inner wall of the nipple is cylindrical for a suitable distance and is then tapered downwardly to form a seat 10 for Fluid channels 11 in the nipple discharge into an annular groove 12 connecting with passages 13 in the head 1, through which flushing fluid may reach the cutters 2 at the bottom of the hole.

The core'catcher is normally positioned in the cylindrical portion of the nipple 1. It

1928. Serial No. 269,314.

comprises a sleeve 14 of steel, the upper portion of which is tapered downwardly to allow room for play of the jaw arms. Below the tapered portion the sleeve has a cylindrical skirt 16 and the lower end is beveled eXteriorly at 15.

The cylindrical skirt 16 has a plurality of slots or recesses 17 cut therein from the lower end upwardly to the line of the tapered portion. These slots are to ,receive core-engaging jaws 18 the inner faces of which are toothed to resist relative downward movement of the core. The outer faces of the jaws are tapered to fit the seat 10.

The said jaws 18 have each a transverse cylindrical opening 19 therein and a slot connects therewith to receive the lower end 21 of a spring arm 20 the end of which is rounded to fit said opening. The upper ends of the jaws are cut away somewhat above the recess to allow free play of the jaws on the spring arms 20. Said spring arms are straps of steel secured on the outer face of the sleeve 14 at the. upper end. They extend downwardly with a normal outward inclination to hold the aws out of contact with the core, and because of the pivotal connection formed between the end 21 of each arm and the jaw, the jaw may pivot around the transverse recess in which the rounded ends 21 engage the jaws. The slots leading to the recesses are made of suflicient width to allow this movement within the desired limits.

Within the sleeve 14 the inner diameter is slightly enlarged above a shoulder 22 thus providing space to receive resilient core-engaging arms 23 of flat steel. These arms are inclined laterally in a spiral shape, rearwardly relative to the direction of rotation of the drill. The upper ends are bent inwardly, as seen from Fig. 2, the ends being thereby brought into the path of the core: which will tend to press the said arms outwardly.

In operation the parts of the drill and core catcher are assembled as seen in Fig. 1. It will be noted that the jaws 18 are readily attached to the arms 20 by sliding the rounded ends 21 of said arms transversely of the jaws into the openings 19. lVhen thus assembled the spring arms 20 tend to hold the jaws resiliently outwardly against the upper end of the seat 10 thus maintaining the assembled core catcher at the upper end of the chamber.

In drilling, the core will be gradually extended upwardly relative to the core catcher and will not be engaged by the teeth of the jaws as the said jaws will be projecting outwardly from the sleeve 14. The arms 23 will rub upon the core, but, because of their spiral arrangement, they will not wear the core materially. When the core has been cut of sufficient length, the drill will be raised from the well. The arms 23 will resist relative upward movement of the drill and will force the sleeve and jaws into the seat 10, thus contracting the jaws against the core. Because of the pivotal connection between the arms 20 and the jaws 18 the jaws will be allowed to move radially inward without tipping from the vertical. The entire inner face of the jaws will thus engage the core and tend to hold it securely so as to break the core off and carry it with the drill to the surface.

The advantage of this type of core catcher over other similar tools of this character wherein the jaws are suspended on arms lies particularly in the fact that the jaws are not prevented from assuming a vertical core engaging surface at all times. The jaws will therefore, present their entire length to the core, and will engage it securely. The jaws have the same advantages as where they are loosely mounted in position unconnected with the holder. The arms 20 tend to hold the jaws out of contact with the core and thereby prevent wear upon the teeth While the core is being cut.

What I claim is:

1. In a core drill having an inner core passage and a downwardly-tapered seat therein, the combination of a core catcher including a sleeve tapered downwardly from the upper end, a lower cylindrical skirt thereon, spring arms secured to the outer face of said sleeve, toothed jaws secured pivotally to said arms, and fitting through slots in said skirt, in the manner described.

2. In a core drill having an inner core passage and a downwardly-tapered seat therein, the combination of a core catcher including a sleeve tapered downwardly from the upper end, a lower cylindrical skirt thereon, spring arms secured to the outer face of said sleeve, toothed jaws secured pivotally to said arms, and fitting through slots in said skirt and means separate from said jaws to resist upward movement of said sleeve relative to the work.

3. In a core catcher a sleeve having slots at its lower end, toothed jaws movabl'e radially in said slots, and spring arms secured to said sleeve and said jaws to hold said jaws outwardly and a pivotal connection between said jaws and said arms to allow said jaws to present their inner faces parallel with the core, said pivotal connection including a bead on the lower end of each arm fitting within a morticed groove in the jaw.

4. In a core catcher, a sleeve tapered downwardly on its outer face and having slots therein, toothed jaws movable radially in said sl'ots, resilient means suspending said jaws from the upper end of said sleeve and having a pivotal connection with said jaws to permit said jaws to remain upright.

In testimony whereof I hereunto affix my signature this 9th day of April, A. D. 1928. s

LOUIS H. WELLENSIEK.

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