US2119731A - Drill pipe slip - Google Patents

Description

June 7,1938. I w. A. AB EGG 2,119,731

7 DRILL PIPE SL'IP Filed Oct. 19, 1936 2 Sheets-Sheet 2 11v VENTOR WALTER [-3. HDEGG ATTCRIVEY Patented June 7, 1938 DRILL PIPE SLIP Walter A. Abegg, Los Angeles, Calif., assignor of I one-half to Baldwin Reinhold, Los Angeles,

Calif.

Application October 19, 1936, Serial No. 106,407

Claims.

This invention relates to well drilling equipment, and particularly pertains to a drill pipe slip.

In connection with .the drilling of wells, and particularly when drilling oil wells, it is often necessary to support the drill string without the assistance of the traveling blocks and supporting cables. A common method of accomplishing this result is to use a plurality of drill slips which have gripping wedge faces and which may be introduced into the space between the drill string casing or the like, and suitable seats in the rotary table. There are usually several of these slips required for each gripping operation and this requires considerable time to place the slips in position and remove them. It is desirable therefore to provide slipunits comprising a plurality of slips adjustably connected so that they will adapt themselves to the circular contour of the drill string, and it is of further advantage to provide gripping faces which readily adjust themselves to the surface to be gripped, and which may be readily replaced and interchanged as they wear, or for other reasons. It is the principal object of the present invention to provide a drill pipe slip especially of the type known as a two-man slip, which embodies a plurality of separate slip sections articulately connected and movable as a unit. It is a further object of the present invention to provide a slip having composite gripping faces which will readily adapt themselves to the surface being gripped and which may be easily removed, interchanged, or replaced.

The present invention contemplates the provision of drill slip units comprising a plurality of slip sections articulately connected and fitted with a single handle, the gripping faces of said sections comprising a plurality of separate inserts assembled in vertical rows and detachably secured in position.

The invention is illustrated by way of example in the accompanying drawings in which:

Figure l is a view in plan showing a pair of slip units, one in horizontal section and the other in top elevation as applied to a drill stem or the like. Fig. 2 is a view in vertical section through one of the slip units as seen on the line 2-2 of Fig. 1. Fig. 3 is a view in elevation showing the gripping face of a slip unit with a series of slip inserts in position and one series removed to disclose the construction and application of the slip inserts.

Fig. 4 is a view in elevation showing the rear side of a slip unit particularly indicating the manner in which two slip elements are assembled.

Fig. 5 is a view in perspective showing one of the slip inserts.

Fig. 6 is a view in section and elevation showing another form of the gripping inserts.

Referring more particularly to the drawings, ill indicates a drill string or the like adapted to horizontal section. This wall is reinforced on its rear side with a plurality of horizontal webs i5 which are progressively reduced in diameter toward the bottom'of the wall. Cast integral with the outer ends of the webs I5 is an inclined wedge wall l8 which is arcuate in horizontal section and would fit within and conform to a suitable seat within a rotary drilling table. For purposes of convenience in anchoring the cores forming the spaces between the webs during the casting of the slip units the back wall i6 is formed with a longitudinal opening i'I as shown in Fig. 3 of-the drawings, and as further indicated in Fig. 1. This makes it possible to inspect the cores and to likewise inspect the finished casting to insure ,Vhat' there has been a proper flow of metal within the mold. The right and left hand slip units are provided with interlocking means whereby they will beheld together for articulate movement. This means, as particularly shown in Figs. 1 and 3 of the drawings, comprises a pair of tenon lugs l8 which extend into mortise grooves IS. The grooves i9 are formed by an outer shoulder and an opposing shoulder 2|. The outer shoulder 20 has a semicylindrical face 22 which seats against an arcuate face 23 carried by the opposing slip unit. .The tenon I8 has a partial cylindrical face fitting against a corresponding face of the mortise iii. A locking shoulder 24 is formed on the tenon and hooksover a corresponding shoulder 25 formed upon the portion 2! of the mortise. An arcuate face 26 is formed "on the tenon adjacent to the locking shoulder 26 and a partial cylindrical face 25 of the mortise member 2i susbtantially conforms thereto. It will thus be seen that the mortise and tenon while interlocked for a rolling action with relation to each other permit the right and left hand slip units to adjust themselves to the circumference-of the member to be gripped. By reference to Fig. 3 of the drawings it will be seen that the mortise structures and the tenon structures are arranged in spaced pairs, thus making it possible for the mortise and tenon elements to be placed in position for vertical movement with relation to each other and to then be slipped into their proper places and in interlocking relation. In order to maintain the mortise and tenon lugs in interlocking relation to each other a spacer spool 21 is interposed between the adjacent members 'of interlocked mortise and tenon elements. The spacer is held in position by a bolt 28 carried by one of the slip castings and extending through the spacer. The entire structure including the right and left hand slip units i2 and i3 is assembled and held in its assembled position by a handle 23 which is formed at its opposite ends with eyes extending between lugs 33 and 3|. A pair of these lugs project upwardly from the upper web I5 of each of the slip unit castings and are held by handle bolts 32. It will be recognized that since the handle has some flexibility it will yield sumciently to allow relative movement of the slip sections of each slip unit.

The gripping faces of the slips are of novel design and construction, and permit rapid installation of the gripping elements and allow the gripping elements to automatically adjust themselves to the surface being gripped. The arcuate face 33 of the portion 34 of the slip casting is formed with a plurality of circular bores 34'therethrough, said openings being arranged in' vertical rows and extending radially of the face 33. Formed concentrically with said bores and in the face 33 are counterbores 35. The openings 33 are spaced closer together than the diameter of the counterbores so that a series of seats will be formed, the circular edges of which extend lengthwiseof the face 33, as a series of scallops. Mounted in each of the bores 34 is a slip insert 33. These are shown in detail in Fig. 4 where it will be seen that they are formed with a cylindrical shank 31 which will fit into a bore 34. The shank 31 carries an enlarged head 33 which has arcuate sides 33 conforming to the arcuate portion of the counterbores 35. The upper and lower sides of the heads 33 are fiat, as indicated at Land when seated within the counterbores 35 extend transversely of the face 33 so that adjacent flat portions of adjacent heads 33 will abut against each other preventing independent rotation of the inserts. A filler segment Al -is fixed in the lowermost counterbore of each set of counterbores 35 so that the lower flat face 33 of the lowermost insert 33 will seat against this abutment, which will prevent rotation of all of the inserts 36 in the series. The face of the head 38 is arcuate as indicated at 42 so that it will conform to the circular section of the member I0, which is to be gripped. This arcuate face is preferably knurled or otherwise roughened so that it will positively grip the surface. Each of the shanks 31 of the inserts are formed with a transverse opening 43 through them. The shanks 31 are of sufilcient length to insure that they will extend entirely through the wall plates ll of the slips and receive a pin 44 which extends downwardly through the aligned openings in the various shanks 31 and will hold all of the shanks in their seated position. It is desirable that the bores 34 which receive the shanks 31 shall be slightly larger in diameter than the shanks so that there will be slight lateral movement of the individual inserts to accommodate irregularities in the contour of the member i0. I

In operation of the present invention the individual slip sections, comprising the castings, are machined as shown in Figs. 1 and 3 of the drawlugs, and are assembled as shown in Figs. 1 and 4 of the drawings. When so assembled a righthand section 12 and a lefthand section 13 are placed with their mortise and tenon units in interlocking relation by placing these portions 1 of a pair of slip sections i2 and I3 in overlapping position and in register so that, when the two sections are moved to positions of horizontal alignment the sections will be interlocked to form a slip unit. A series of inserts 33 is then installed with the shanks 31 within the bores 33 and with the pad portions 33 seated within the counterbores 35. In this position the rod 43 is inserted through the passages 33 of the various insert shanks 31, as shown in Fig. 2 of the drawingsso that the inserts will be held assembled with the slip sections. The handle 23 is assembled with the slip sections of each unit and the spacer spool 21 is placed in position between the mortise-and tenon lugs. Thus the entire structure is assembled and ready for operation. In operation it. will be evident that the slip sections will adapt themselves to the contour of the element l0 being gripped, and that the knurled surface of the inserts 33 will provide a desirable gripping face. In the event that the knurled inserts 33 become damaged in any way, or in case it is desired to interchange inserts to accommodate elements ill of different diameters the rods 44 may be withdrawn to permit instant removal of an entire vertical row of inserts or to permit individual inserts to be installed in place of the damaged ones.

Referring more particularly to Fig. 6, it will be seen that the insert 33 there disclosed is formed with a back face 50 which is convexed and spheroidal. This seats against a concaved bottom face 5! in the body 33 of the slip, said bottom face being circumscribed by a cylindrical bore 52, the diameter of which is slightly greater than the diameter of the outside diameter of the heads 33 of the slip inserts 33. A bore 34 through the slip body is greater in diameter than the cylindrical shank 31 of an insert extending therethrough.

It will thus be seen that as pressure is exerted upon the gripping face of the head 33 in a direction off-center from the longitudinal axis of the shank 31 the head 38 may properly adjust itself due to the sliding action between the back face 50 of the head and the concaved bottom face 51 of the bore 52. This insures that the entire gripping faces of the heads will contact the surface of the element being gripped.

It will thus be seen that the drill slip structure here disclosed makes it possible for four slip elements to be handled by two men and for the slip elements to readily adapt themselves to the seat within which they are placed and with the element to be gripped, and furthermore prothe event one or more of the slip inserts become 1 damaged they may be removed and replaced without making it necessary to replace the entire row of inserts as is the case at present where a continuous and solid insert is used.

While I have shown the preferred form of my invention as now known to me, it will be understood that various changes might be made in the combination, construction, and arrangement of parts, by those skilled in the art, without departing from the spirit of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A drill pipe slip structure comprising a pair of slip elements each having a body casting formed with a vertical front wall and an inclined back wall, the horizontal wall sections being arcuate to conform substantially to the surface of a member being gripped and to rest within a tapered seat, means along contiguous edges of said elements for articulately interlocking said elements and holding them in assembled relation to each other, a handle common to the two elements, one end of the handle being secured to one of the elements and the other end of the handle being secured to the other of said elements, and a block interposed between said interlocking means to maintain them interlocked.

2. A drill pipe slip structure comprising a body casting having a vertical front wall of arcuate horizontal section, a rear face adapted to conform to a seat in the rotary table, the vertical face of the casting being formed with a plurality of horizontal bores extending thereinto and arranged in vertical rows, enlarged counterbores formed in the vertical face concentric with said bores and of a diameter greater than the vertical distance from center to center of adjacent bores, and gripping inserts formed with shanks extending into said horizontal bores and with enlarged heads fitting into the counterbores, the opposite horizontal sides of said heads being flat so that the flat portions of adjacent heads will abut against each other to prevent their rotation.

3. A drill pipe slip structure comprising a body casting having a vertical front wall of arcuatehorizontal section, a rear face adapted to conform to a seat in the rotary table, the vertical face of the casting being formed with a plurality of horizontal bores extending thereinto and arranged in vertical rows, enlarged counterbores formed in the vertical face concentric with said bores and of a diameter greater than the vertical distance from center to center of adjacent bores, and gripping inserts formed with shanks extending into said horizontal bores and with enlarged heads fitting into the counterbores, the opposite horizontal sides of said heads being fiat so that the flat portions of adjacent heads will abut against each other to prevent their rotation, the faces of said heads being curved horizontally to conform to the cylindrical face of the object being gripped.

4. A drill pipe slip structure comprising a body casting having a vertical front wall of arcuate horizontal section, a rear face adapted to conform to a seat in the rotary table, the

vertical face of the casting being formed with a plurality of horizontal bores extending thereinto and arranged in vertical rows,- enlarged counterbores formed in the vertical face concentric with said bores and of a diameter g'reaterthan the vertical distance from center to center of adjacent bores, and gripping inserts formed with shanks extending into said horizontal bores and with enlarged heads fitting into the counterbore, the opposite horizontal sides of said heads being flat so that the flat portions of adjacent heads will abut againsteach other to prevent their rotation, the faces of said heads being curved horizontally to conform to the cylindrical face of the object being gripped, said faces being abraded.

5. In combination with a drill pipe slip body,

having a plurality of horizontal bores therefor arranged in vertical spaced relation to each other, grippinginserts. each comprising a shank adapted to be secured within individual bores, said inserts each having an enlarged head formed with opposite flat horizontal faces which abut against each other upon contiguous heads and thus holding the heads against rotation while providing a continuous gripping face.

6. In combination with a drill pipe slip body 'having a plurality of horizontal bores therefor arranged in spaced relation to each other, gripping inserts each comprising a shank adapted to be secured within individual bores, a plurality of grooves formed on the inner face of said drill pipe slip body, said inserts each having an enlarged head formed with opposite flat horizontal faces which abut againsteach other upon contiguous heads, said heads seating within said grooves. f

'7. In combination with a drill pipe slip body having a plurality of grooves, a plurality of hori-' zontal bores therefor arranged in spaced relation to each other, gripping inserts each comprising a shank adaptedto be secured within said bores, said inserts seating within said grooves and each having an enlarged head formed with opposite flat horizontal faces which abut against each other upon contiguous heads to. prevent their rotation;

8. In combination with a drill pipe slip body having a plurality of grooves formed on the inner face thereof and arranged in spaced relation to each other, gripping inserts each comprising a shank adapted to-be secured within individual bores, said inserts having an enlarged head formed with opposite fiat horizontal faces which abut against each other upon contiguous heads, the opposite faces of which abut against the side wall of said grooves, said arrangement preventing rotation of the gripping inserts.-

9. In combination with a drill pipe slip body having a plurality of grooves formed on the inner face thereof and arranged in spaced relation to each other, gripping inserts each comprising a shank adapted to be secured within individual inclined back wall, the horizontal wall section being arcuate to conform substantially to the surface of a member being gripped and to rest within a tapered seat, means along contiguous edges of said elements for articulately interlocking said elements and holding them in assembled relation to each other, a block interposed between said interlocking means to maintain them in interlocked relationship, a plurality of grooves formed on the vertical front wall of the drillpipe slip body, said grooves having a plurality of bores therein arranged in spaced relation to each other, gripping inserts each comprising a shank adapted to be secured within individual bores,

said inserts each having an enlarged head formed serts will be held in spaced relationship with the drill slip body.

WALTER A. ABEGG.

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