US2429929A - Swivel - Google Patents

Description

Oct. 28, 1947. R. P.v FISHER SWIVEL FiledA Aug. 28 1944 INVENTOR A70 erf P /Scr ATT o R N EY Patented Oct. 28, 1947 UNITED STATES PATENT FFICEy SWIVEL Rtert P. Fisher, Los Angeles, Calif. Application August 28, 1944, Serial No. 551,579

3 claims. (c1. 25er-25)' ing a rotating member, and particularly to one in` which fluid under pressure must be transmitted to a tubular rotating member. Such devices, commonly called swivels, 'are extensively employed in the oil industry for supporting the rotating drill string used in the rotary process of oil Well drilling.

It is an objectof this invention to provide 'a swivel of improved and simplified construction.

It is another object of this invention to provide a swivel capable of supporting a great weight of a long string of drill pipe, and embodying for this purpose, a plurality of thrust bearings employing rolling bearing element-s; v

In addition to supporting the drill string, the swivel provides a connection between a stationary conduit connecting a sourcefof supply of drilling liquid and the drill string. Such iluid carries a large amount of abrasive material and must be supplied under pressure, which is frequently of the order of a thousand pounds per square inch. The problem of preventing leakage of such fluid between the rotary and non-rotary lelements ofv the swivel is thus a di-ii'icult one. It is thus an-V -other object of this invention to provide a swivelv having improved means preventing leakage of the drilling fluid.

This invention possesses many other advantages, and has other objects which may be` made more clearly apparent Vfrom a `consideration of one embodiment of the invention. For this purpose there is shown a form in the drawings accompanying and forming part of the present specilcation; The form will now be described in detail, illustrating the general principles of the -in vention; but it isto be understood that this detailed description is not to be taken in a limiting sense, since the s'cpe of this invention is best dened by the appended claims.

Referring to the drawing:

Figure 1 is an axial section through a swivel embodying the invention, the innermost or sealing member being shownpartly in elevation;

Fig. 2 is a sectional view, partly in elevation",

tagen along plane 2-2 oi Fig. l;

*Figs 3 is Fawlcro'ss sectional view taken along plane `3,- 3V of Fig 2; and n Fig. 4 is a detail section of the seat which supports the sealing member.

As shown in Fig. 1 of the drawing, the swivel comprises outer and inner tubular members I and 2 in telescopic relationship. The outer member I is adapted to be suspended by a bail 3. The inner member 2 is rotatably supported on the outer member I by a plurality of rolling bearing elements 4; Vthe drill string 5 is secured to its lower end. Drilling liquid is supplied to the drill string :through agoose neck 6, a packing member lbeing provided to prevent escape of this liquid between the members I and 2.

Referring in more detail to the swivel, the outer member I is provided with reduced threaded portions Ill and II respectively at its upper and lower ends. A cap or closure member I2 is threaded in the upperv portion IIJ and provides a chamber I3, which communicates with the passage l4 which extends axially through the inner member 2. The goose neck 6 is threaded into cap I2, opening into chamber I3; itis adapted to Vbe connected with the source of supply of drilling lluid by aflexible conduit (not shown). The bail`3 is pivotally secured to cap I2 at diametrically opposite points Aon :the outside thereci bymshoulder screws I5 threaded into the cap I2. The bail 3 serves to suspend the swivel and the drill 5 from a hook I6 vas is well understood.

The bore I1 of member I has a plurality of axiallyV spaced bearing races I8 formed therein to accommodate the bearing elements Il. These races are so formed that the bearing elements 4 which `may be inthe form of balls, extend therefrom into cooperating bearing races I9 formed in the exterior surface 2D of the inner or rotary member 2 and which is telescopedv in bore Il. "Since theelemen'ts 4 are spherical, each of the races, I8, I9, is of hemispherical crosssection. In this way the balls l are in shear between members I and 2 and tr-ansfer axial force between the members. Further, any lateral force is transferred between the members by the engagement of balls 4 with the bottoms of the races. Thus any tendency of .the members to cramp due to axial misalignment, as by twisting and side thrusts on drill string 5, is prevented. Since the balls A are arranged in longitudinally spaced ser-ies otrace's that extend over a considerable distance in an axial direction, the guiding of the rotary member 2 is effected without any danger of cramping.

The lower reduced end Il of member I has a guide member 2--I threaded thereon with a, bore 22 for accommodating the lower extension 23 of member 2 which is of reduced diameter.. Member 2I has an outside diameter which is slightly greater than the outside diameter of the outer member I, thus providing an upwardly directed shoulder 24 for supporting a sleeve 25 telescoped over the exterior of member I. Cap I2 similarly has a greater outside diameter than member I and 'thus cooperates with member 2| to secure sleeve 25 in place. As shown in Figs. 2 and 3, sleeve 25 is for the purpose of retaining plugs 26 in place in member I. These plugs 26 serve to close openings 21 which extend from the exterior of member I into races I8. These openings 21 permit the balls 4 to be placed in their cooperating races I8, I9 after the members I and 2 have been assembled, or to permit removal of the balls 4 for replacement, or in order that members I and 2 may be disassembled.

The bore I4 of the inner member 2 has a threaded portion 28 at its lower end for attaching the drill string to the member, and is of enlarged diameter as at 29 for accommodating the packing member 1. This packing member comprises a hollow mandrel 30 rotatably supported in bore 29 as by aseat 3| and having a head 32 positioned in bore I1 above the inner member 2. 'I'he mandrel 38 is restrained against rotation as by a pin 33 threaded into member I and engaging a notch 34 in head 32. For sealing between the head 32 and the Wall of bore |1, one or more spring rings 35 such as are commonly known as piston rings may be provided, being accommodated in annular grooves 36 formed in the head. These rings are preferably of the step-cut type, as shown in Fig. 1.

Pressure in chamber I3 acts on head 32 to force mandrel 30 to its seat 3| and it is necessary that leakage be prevented at this point to prevent escape of the drilling fluid from the swivel. Accordingly, the surface 31 which joins passage I4 with its enlarged portion 29 is inclined downwardly and inwardly, and the lower end of mandrel 39 is correspondingly inclined as at 38 (Fig. 9) so as to seat therein and form a liquid tight jointl Since there is relative rotation between mandrel 30 and the member 2 in which it is seated, and the force urging the mandrel to seal may be considerable, it is desirable to provide means for reducing the wear of the seating surfaces 31 and 38. For this purpose, means are provided forming a ball thrust bearing for supporting mandrel 30. Thus, an annular groove 49 is provided about mandrel 3|) at such a position that balls 4| accommodated in the groove will bear upon inclined surface 38 as well as upon the wall of the enlarged passage 29 (see Fig. 4)

Groove 40 is cut slightly higher than its desired position with respect to surface 38, where mandrel 39 is made. Thus when the mandrel is first put in use with member 2, the full force urging mandrel 39 downward urges surface 33 against surface 31 so that relatively rapid wear occurs to quickly cause these surfaces to properly seat. After such initial wearing in has taken place, this force is transmitted between the mandrel 30 and member 2 by the balls 4I bearing on surface 31, and this wear is thus substantially checked. A very small amount of wear occurs on the ball race 40 and also on that area of surface 31 contacted by the balls 4I, and this is sufficient to insure the maintenance of a liquid tight seal between surfaces 31 and 38. By so reducing the wear between these surfaces, the useful life of the mandrel 39 and also of the member 2 is greatly increased.

I claim: f

1. In a swivel, a stationary member having a bore, a rotatable member having an exterior cylindrical surface closely spaced in telescopic relation with said bore, there being opposed aligned circumferential grooves respectively in said bore and said surface, forming cooperating bearing races, rolling bearing elements interposed between said members in said races, said rotatable member having an axially extending through passage, said bore extending beyond said rotary member, means on said stationary member closing the extending portion of the bore, a tubular sealing element having a head in said bore extension, means sealing between said head and said extension, and means forming a seat in said passage for supporting and sealing against said element.

2. In a swivel, a stationary member having a. bore, a rotatable member having an exterior cy lindrical surface closely spaced in telescopic relation with said bore, there being opposed aligned circumferential grooves respectively in said bore and said surface, forming cooperating bearing races, rolling bearing elements interposed between said members in said races, said rotatable member having an axially extending through passage, said bore extending beyond said rotary member, means on said stationary member closing the extending portion of the bore, a tubular sealing element having a head in said bore exten* sion, means sealing between said head and said extension, means forming a seat in said passage for supporting and sealing against said element, and means restraining said element against rotary movement with respect to one of said members.

3. In a swivel, a stationary member having a bore, a rotatable member having an exterior cylindrical surface closely spaced in telescopic relation with said bore, there being opposed aligned circumferential grooves respectively in said bore and said surface, forming cooperating bearing races, rolling bearing elements interposed between said members in said races, said rotatable member having an axially extending through passage, said bore extending beyond said rotary member, means on said stationary member closing the extending portion of the bore, a tubular sealing element having a head in said bore extension, a snap ring interposed between said head and said extension for sealing therebetween, means forming a seat in Said passage for supporting and sealing against said element, and means restraining said element against rotary movement with respect to said stationary member.

ROBERT P. FISHER.

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

UNITED STATES PATENTS Number Name Date 1,280,536 Petersen Oct, 1, 1918 1,522,226 Bowles Jan. 6, 1925 1,701,898 Seifert Feb. 12, 1929 2,346,380 King Apr. 11, 1944 2,195,501 Smith Apr, 2, 1940

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