US1520971A - Underreamer - Google Patents

Description

Dec, 30, 1924.

R. R. SMITH lUNDERmmvnzfi Filed Feb. 20, 1922 JIU Patented Dec. 30, 1924.

UNITI-:D STATES 1,520,971 PATENT @imei-1.;

RICHARD It. SMITH, or ToItRANCE, CALIFORNIAAssICNoB. To UNION .TooLCoM- lPANY, or TOImANCE, CALIFORNIA, A CORPORATION or CALIFORNIA.

UVNDERREAMER.

Application filed February 2011922. serial iN'.' 533,001.l

)To all 'whomz't may concern: i Be it known that I, RICHARD R. SMITH, a citizen of the United States, vresiding at Torrance, in the county of Los Angeles and 1 means for locking the key against displacement.

Another Objectis to movable cutter supporting key yassoclated with a spring rod and engaging 1n transverse openings .in vthe cuttersand removable through one of said openings after lirst being moved to a tilted position, means as sociated with one of the cutters preventing such tilting movement of the key until saidl be more fully apparent'from the followingk description and the -accompanyin drawings, which form a partof this `dlsclosure,

and which illustrate a preferred form of embodiment of the invention.

Of the drawings: r Fig. l is a side elevation of the lower end of an underreamer embodying my improvements. t r V Fig. 2 is a vertical section on line 2 2, of Fig. 1. Fig. 3 is a locking means. r

Fig.4 is a perspective view ofthe cutter supporting key. t f' Described in general terms, the underreamer illustrated in the` drawings consists of abody 1 having a central bore in which slides a spring rod or mandrel 2 normally subjected tov an upward tension of a spring 3 which'is positionedin aspring chamber 4 and surrounds the rod. 'lhe lower portion of the body has o posedropen slipways 5 on opposite 4sides o the rod 2 in` which perspective view'of the. key

rovide with a re.

slide the lshanksjtot the. respectivefc'utters or slips-7, the side walls vofthecutter Shanks beingprovidedwith out-thrust bearing ribs v8 'adapted to 'l engage in' corresponding grooves 9 in the side walls of the slipways 5.v

The inner `face ofeach shank 6 is cut away to form an inclinedshoulderlO which engages under the respective expanding shoulder 11` at the lower4 end of the body when the i cutters 4are in collapsed'position.`

As `thus far described the construction" shownfollowsa general formv of structure more or less lcommon to several well known makes ofunderreamers and it is` thought that specific orfurther description of structure or operation would be superfluous.

v The cutters or slips 7 are supported uponv the lower end of the `rod 2 by afremov'able.

key 12 which loosely engages through a transverse 'slot 13 in saidrod with its opposite ends Or tangsextending into slots 14 inv the shanksi ofthejrespective slips. One i of the slots, for 'example the-right hand'slot, is of justsuiicient vertical-depthto receive the adjacent-end of the` keyand maintain substantial engagement with its edges. The medial portion of the key12 has an 'eXtension or wing 15 which projectsy 'upwardly f between the -two clutterl shankslso that `as long as the'key is maintained in a normal position it is retained against displacement.4

At the outeil ends the upper edge of the key is included downwardly,as` at 16,-so as lto permit a tilting `ot the cutters or'slips during' their vertical movements in the slipways incident to acollapsing or expanding of the cutters.` l

In removing the slips or cutters 7 from the body it is'lirst necessaryto removefthe key 12y through the slotll ofone yof the'cutters and orthis' reason'said slot, as-for in-y` stance that of the le'ft hand cutter in Fi ter to permit a tilting of the 'key and its removal endwise through the slotf'o saidi cutter shank, as' indicated in dotted lines.- This tilting is facilitated because `I allow clearance -above and 4below the right hand tang of the key'inthe vslot'of the right' hand cutter as illustrated'in Fig.`2. It will be* understoodthat such tilting ofthe key 12 for subsequent, removal, is v`necessary 'in or- -derthat the ex'tensionyl5` may clearvthe upper edge of the slot 14, and it will also be evident that to accomplish a removal of the key 12 it will be necessary to ulldownwardly upon the spring rod 2. uch downward pull on` the sprin rod is effected by engaging a rod 17,as indicated in dotted lines in Fig. 2, into a screw threaded recess in the lower end of the spring rod, and applying suliicient pulling power vtosaid rod 17 to overcome the tension of the spring 3. The inclined edge 16 on the end of the key remote from the locking member facilitates this tilting of the keys, see Fig. 1.

It has been found desirable in this type of underreamer to provide some means. of positively locking the key against removal so as to obviate any likelihood of the parts becoming deranged through use or wear and to prevent an accidental loss of the key, especially while the underreamer is being operated in a well bore, as such accidental loss of the key would result in a loss of both cutters.

To positively lock the key 12 in assembled position I providev allock member20, associated with the left hand cutter in Fig. 2, said member having a beaded lower edge 21 provided with a threaded recess 23, and a transverse aperture 24. This lock member is in the form ofa plate extending longij tudinally with the key, and it has a sliding fit in a recess 25 vertically-aligned and com-v municating with the slot 14 in the cutter shank 6 and is retained in position by a rivet 26 extending through the walls of said recess and throughthe aperture 24, with the upper edge of the lock member positioned below the lower edge of the adjacent end of the key 12 (see Fig. 2.) When assembled in this relation, the surface of the upper edge of the lock member 20 extends longitudinallyunder the key, engages it, and prevents a tilting of the key 12 so that the key is positivel locked against removal.

A ter first removing therivet 26 the lock member 20 may be removed by the use of any suitable form of tool screwed into the threaded recess 23.

.It will be apparent from the' above that I have provided a structure in which the key when locked in assembled position, has no appreciable vertical movement within the key slots in thecutter shanks, orwithin the key slot inthe spring rod, the lock member 20 serving as a means for positively insuring a coincident vertical movement of both cutters, the key, and the spring rod in both directions. f

This is of great importance in that by such arrangement back-lash of the cutters relative tothe key is prevented and the wear incident toy such back-lash is eliminated.

Furtherwith the ordinarykey structure wherein the 'key slots in the cutters are of al height equal to the height of the center portion of the key, the key is maintained in position only bythe tension of the spring and the ends of the key bein of lesser height than said slots permit an in ependent movement vof one or both cutters upon the key. l/Vith such ordinary construction, if one of the cutters becomes jammed in the well bore an upward pull on the underreamer will cause thekey to become twisted to an angled position with the corner of its medial projection wedging against the jammed cutter, then upon a downward movement such corner will be forced into the key slot of such jammed cutter with the result that all the parts become locked together against movement.- If the parts cannot then be released by operation of the jars of the tool' string, the `tool must be forcefully pulled from the well with the result that one or both of the cutters engaging the casing shoe will be broken and lost from the tool.

By preventing an independent movement A of the cutters on the key the structure of the presentinvention `eliminates any such wedging or-jamming of the parts.

While the form of device herein illustrated and described is well adapted for the purposes primarily stated, itis to be understood that I do not wish to confine the invention to-thevone embodiment herein disclosed,.for it is susceptible of embodiment in various other forms all coming Within the scope of the claims which follow.

I claim: Y 1. In an underreamer, the combination ofa body, a spring rod mounted rin the body and provided with a transverse key-receiving slot, opposed cutters having shanks provided with key-slots substantially aligned with the key-slot of the rod, a cutter-supporting key insertable in an inclined position through the aligned slots -when the spring rod is in a depressed position with its slot alignin with the slots of the opposed cutters, an a lock-member seated in the side of one of the cutters, having an upper edge with its surface extending longitudinally under, and engaging, the edge of said key for maintaining the key against displacement, said lock-member being removablek to permit withdrawal of the key, the slot of the cutter opposite the locking member being of greater length than the depth .of the endA of the key engaging therein, to permit clearance in inserting the key.

2. In an underreamer, the combination of a body, a pair of oppositely disposed cutters with slots therein, a spring-rod disposed between the cutters and carried by the body, said spring rod having a slot therein, a key received in said slots, the slot in one of said cutters being of suflicient vertical width to receive the adjacent end of the keyand substantially engage the upper and-lower edges of the key, the slot in the other cutter 'being of considerably greater vertical width than the end of the key to permit tilting the key when inserting or withdrawing the same, the last-named or said cutters having a removable-locking member for engaging the lower edge of the key to prevent the same from being moved downwardly at that end, the upper edge of the key at the end remote from said locking member being inclined to facilitate the downward movement of the end of the key adjacent the locking member when the key is being removed.

3. In an underreamer, the combination of a body, a pair of oppositelv disposed cutters with slots therein,a spring-rod disposed between the cutters and carried by the body, said spring rod having a slot therein aligned with the slots in the cutters, a key having a wing at the slot of the spring-rod, the slot in one of said cutters being of suiiicient vertical width to receive one end of the key and substantially engage the key on its upper and lower edges, the slot in the other cutter being of considerably greater vertical width than the adjacent end of the key to permit tilting the key when inserting or withdrawing the same, the last-named cutter having a recess adjacent the end of the key, extending from N the outer face of the cutter inwardly toward the axis of the body, and a locking member removably mounted in said recess and engaging the adjacent end of the key to retain the same.

4. In an underreamer, the combination of a body, a spring-rod mounted therein and having a slot` a pair of oppositely disposed cutters carried by the body and having slots opposite the slot in the spring rod, a key having its ends received in the slots of the cutters and having a wing projecting up' wardly on the upper edge of the key and engaging the inner sides of the cutters to prevent displacement of the key, the slot in one of said cutters being of sufficient vertical width to receive the adjacent end of the key and substantially engage the key on its upper and lower edges, the slot in the other cutter being of considerably greater vertical width than the adjacent end of the key, so that tue slot in that cutter extends downwardly below the key to permit thel adjacent end of the key to be depressed in inserting or withdrawing the key, the last named cutter having a recess in the side thereof adjacent the end of the key. a locking member removably mounted in said recess and engaging the ad.- jacent end of the key to retain the same, the upper edge of the key at the end thereof remote from the locking member having an its middle portion and received 1nl inclined portion to facilitate the removal of the key when the locking member has been removed.

5. In an underreamer, the combination of a body, a spring rod mounted therein and having' a slot, a pair of oppositely disposed cutters carried by the body :and having slots Opposite the Slotin the spring rod, a key having vvits ends received in the slots of `the v cutters, passing through the slot of the spring rod and having a wing projecting upwardly and engaging the inner4 sides of the cutters to prevent displacement vof the key, one of the slots of said cutters extending i the same, operating to prevent outward` movement of the locking member.

6. In an underreamer, the combination of a body, a spring rod mounted therein and having a slot, a pair of oppositely disposed cutters carried by the body and having slots opposite the slot in the spring rod, a key having its ends received in the slots of the cutters, passing through the spring rod and having a wing projecting upward y and engaging the inner sides of th'e cutters to prevent displacement of the kev, one of the slots of said cutters extending downwardly to permit the adjacent end of the key to be depressed to permit withdrawal of' the key from the slots, a recess in the side of the cutter adjacent that end of the key, said recess extending from the outer face 'of the cutter inwardly toward the axis ofthe body and va locking member removably mounted in said recess and engaging the ad* jacent end of the key to retain the same, the lower edge of said locking member being enlarged to form a bead, said recess receiving said bead and cooperating therewith to prevent an upward movement of the locking member in in the locking member igned at Torrance, California,

day of February 1922.

RICHARD R. SMITH.

in its recess.l

this 10th Witnesses:

MARY ELLEN SMITH, J. A. ENos.

the recess, and means for retainslot of the

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