US3025582A - Spider and slip construction - Google Patents

Description

March 20, 1962 J. s. TAYLOR 3,025,582

SPIDER AND SLIP CONSTRUCTION Filed June 3, 1959 IN V EN TOR.

United dtates Patent ()filice 3,d25,582 Patented Mar. 20, 1962 3,025,582 SPIDER AND SLIP (IGNSTRUCTIGN James 5. Taylor, 119514 E. Admiral Iiace, Tulsa, Gkia. Filed .liune 3, 1959, Ser. No. 817,761 1 Claim. (Cl. 24--263) The present invention relates to spider and slip constructions and more particularly to devices for gripping or for gripping and supporting elongated members such as tubing or the like by means of movable slips of the type useful, for example, in suspending or pulling tubing or casing or the like in Well drilling operations. The invention is an improvement over applicants prior Patents Nos. 2,319,016, issued May ll, 1943, and 2,810,178, issued October 22, 1957.

It is a common practice in this art to provide spider constructions including a body and a pair of slips mounted on the body for vertical movement. Upon downward movement, the slips are wedged toward each other by contact with the body to grip and hold a length of tubing or the like between the slips. The difficulty with this construction is that considerable force is required to reverse the movement of the slips to disassemble the tightly held parts and free the tubing as the slips tend to be firmly held in the assembled position by frictional engagement with the body.

Accordingly, it is an object of the present invention to provide apparatus for gripping or for gripping and supporting elongated members, such as tubing spiders having wedging slips so mounted and arranged as to be readily movable in a reverse direction to free the elongated member from the spider.

It is also an object of the present invention to provide apparatus for the above purpose which will be relatively simple and inexpensive to manufacture, easy to operate, maintain and repair, and rugged and durable in use.

Briefly, the present invention comprises a body member on which are mounted vertically movable slips; but instead of frictionally contacting the body as in the prior art, the slips of the present invention are carried by vertically movable backup members which rest on the body in the lowermost or assembled position, so that the vertical component of force imposed by the weight of the tubing or the like, which is the major component of force on the assembly, is borne by the body merely as a gravity load, while only the minor horizontal component of force comprising the gripping force is borne by the body as a friction load.

Other objects, features and advantages of the present invention will become apparent from a consideration of the following description, taken in connection with the accompanying drawing, in which:

FIGURE 1 is an elevational view of a tubing spider according to the present invention, with the parts shown in raised or released position in full line and in lowered or assembled or gripping position in phantom line;

FIGURE 2 is a side cross-sectional view through the structure of FIGURE 1 showing the parts in their lowermost position except that the slips are shown in phantom line in their initial tube engaging position and in full line in their final tube engaging position;

FIGURE 3 is a perspective view of apparatus according to the present invention; and

FIGURE 4 is a perspective view of a backup member and a portion of its mounting.

Referring now to the drawing in greater detail, there is shown a tubing spider 1 for gripping and supporting a length of tubing comprising a tube 3. Spider 1 comprises a body 5 made up of a pair of parallel vertical spaced side plates 7 having a bottom plate 9 extending between their lower edges. An opening 11 extends vertically through bottom plate 9 to permit the passage therethrough of tube 3. In the illustrated embodiment, bottom plate 9 is integral with one and separate from the other of side plates 7 and bottom plate 9 being held in unitary assembly by means of pins 13 screw-threaded at each end and securing side plates 7 together by screw-threaded engagement in holes through plates 7. Spacer sleeves 15 surround pins 13 and abut against the inner faces of side plates 7 to maintain the desired parallel spacing of side plates 7. It 'will thus be seen that body 5 is unitary, although comprised of separable elements.

Journaled for rotation in side plates 7 are two parallel shafts 17 disposed in a common horizontal plane. One end of each shaft 17 extends outwardly beyond the same side plate 7 and carries on that end a crank arm 19 on the outer side of the adjacent plate 7. The two crank arms 19 are fixedly secured to their associated shafts 17 as by a key and slot arrangement and are identical except that one extends up and the other extends down, as seen in FIGURES 1 and 3. A rigid connecting rod 21 interconnects the free ends of crank arms 19 for pivotal movement relative thereto. An operating handle 23 in the form of a bellcrank lever is mounted for swinging move ment about a horizontal axis on body 5 and is provided at one end with an elongated slot 25 in which is disposed a pin 27 secured to and extending outwardly from an intermediate point on connecting rod 21. Thus, upon manipulation of handle 23, shafts 17 are caused to rotate in opposite angular directions at equal angular velocities, though not necessarily at constant angular velocities. The structure described thus far is similar to corresponding structure in applicants two patents identified above, to which reference may be had for further discussion of the structure and function.

Fixedly secured on each shaft 17 against relative ro- -;tation as by a key and slot assembly is a sleeve 29 disposed between side plates 7. Each sleeve 29 is provided ;With a radially extending arm 31, the two arms 31 ex- ;tending generally toward each other and terminating at ;their ends remote from shafts 17 in recesses 33 provided ;in a pair of backup members 35. A pin 37 secured to ,each backup member 35 bridges the associated recess 33 ;and extends through the end of an arm 31 to provide a ,pivotal connection between arms 31 and backup mem- ;bers 35. In the operative position of the parts, that is, Ebetween and including the uppermost position shown in full line in FIGURE 1 and the lowermost position shown in full line in FIGURE 2, shafts 17 are spaced from each other a distance greater than the distance between backup members 35.

Each backup member 35 has a pair of flat surfaces 39 and 41 which intersect each other at a common straight edge and are related to each other at a large acute angle. In their lowermost position shown in FIGURE 2, backup members 35 rest by gravity on bottom plate 9 with flat surfaces 39 flat against the upper surface of bottom plate 9. Body 5 is thus provided with means for limiting downward movement of backup members 35. In this lowermost position, arms 31 are disposed in a common horizontal plane. Each backup member 35 is thus mounted for limited vertical swinging movement through a path comprising an arc of a circle concentric with the associated shaft 17. During this vertical swinging movement, backup members 35 are most widely spaced apart in their uppermost position and most closely spaced in their lowermost position and continuously progressively approach each other throughout downward swinging movement. As both arms 31 are horizontal in the lowermost position, it is obvious that the tangents to these paths of swinging movement are vertical at that lowermost position.

The surfaces '41 on backup members 35' are opposed to and confront each other in any operative position of the parts. In the lowermost position, they are inclined downwardly toward each other so as to provide a downwardly progressively constricted throat therebetween. In the lowermost position, the lower ends of surfaces 41 are spaced no closer together than the diameter of opening 11 and are preferably spaced a little back from the edge of this opening as seen in FIGURE 2.

Each backup member 35 carries a slip 43 mounted thereon for vertical movement relative thereto. Each slip 43 comprises a Wedge portion 45 that extends down wardly over a major portion of surface 41 on the side: thereof adjacent the other backup member 35. Wedgeportions 45 progressively downwardly decrease in thickness' by an amount corresponding to the downward in-- clination of the associated surface 41, that is, when the parts are in their lowermost position and wedge portion 45 is fiat against its associated surface ll, the interior surfaces of slips 43 contiguous to tube 3 are vertical. These interior surfaces of slips 43 are cylindrical in the illustrated embodiment in accordance with the cylindrical. outer contour of tube 3. If desired, the interior surfaces. of slips 43 may be provided with horizontal serrations; or the like to improve gripping contact with tube Backup members 35 and slips 43 are interconnected for relative vertical movement by means of bolts 47 screwedl into the upper ends of backup members 35 and extendingupwardly therefrom and passing through openings inthe upper ends of slips 43, the heads of bolts 47 retaining the parts in assembly. Coil compression springs 49 sur-- round bolts 47 and act between slips 43 and backup them-- bers 35 continuously to urge slips 43 upwardly" with a force somewhat greater thanthe weight of the slip; Thus, the empty or unloaded position of the slips is the uppermost position thereof shown in phantom line irr FIG- URE 2. i

In operation, with the parts as shown in full line in FIGURE 1, a length of tubing is fed through the spider and through opening 11 between slips 43. Operating handle 23 is then manipulated to lower backup members 35 to the position shown in phantom line in FIGURE 1 and full line in FIGURE 2. At this point, slips 43 are. up in the phantom line position shown in FIGURE 2 and lightly contact the surface of the tubing. As the tubing is lowered further and its weight permitted to rest on;

the spider, slips 43 are drawn down with the tubing into the full line position shown in FIGURE 2. During this. latter movement, backup members 35 do not move as they are already in their lowermost position resting on bottom plate9. They do not move apart, as the aligned linkages: provided by arms 31 in their horizontal position prevent: such movement. Thus, slips '43 are forced inwardly to- Ward each other by wedging action against surfaces 41. and firmly and securely grip the tubing between them. The gripping force is substantially entirely horizontal and thus is transmitted to body 5 in line through arms 33,. through shafts 17 and to the journals of those shafts in side plates 7. Arms 31 do not transmit vertical force imposed on the assembly by the weight of the tubing; instead, this is borne substantially entirely by bottom plate 9 as a gravity load.

To release the assembly and withdraw the tubing, it is necessary only to relieve the weight of the tubing on the assembly, whereupon operating handle 23 may be manipulated in the opposite direction to return the parts to the full line position shown in FIGURE 1, thus permitting easy and rapid withdrawal of the tubing in the reverse direction from its entering direction.

As was pointed out above, the prior art provided devices in which the slips wedged frictionally against the body; and at first glance, it might appear that the present invention simply transfers the friction problem from an interface between the slips and the body to the bearings of shafts 17; However, such is by no means the case, for in A the prior art, all of the forces imposed on the structure were reflected as frictional forces between the slips and the body that had to be overcome before the tubing could be removed from the assembly. But in the present invention, the major portion of the forces imposed by the tubing on the assembly are borne as a mere gravity load by contact of backup members in supported relationship with bottom plate 9. Thus, substantially the entire vertical component of the forces imposed on the assembly is prevented from having a frictional effect; while only the relatively minor horizontal component comprising the actual gripping forces is transmitted to the bearings of shafts 17. Thus, it is relatively quite easy to move the assembly of tube 3 and backup members 35 and slips 43 initially upward from the lowermost position. Although in the lowermost position this asv sembly is quite firmly held together by frictional forces,

as soon as it rises an appreciable distance from its lower- .most position, the. components of the assembly separate :for they swing farther apart from each other about their respective axes of swinging movement.

From a consideration of the foregoing disclosure, it will be obvious that all of the initially recited objects (of the present invention have been achieved.

Although the present invention has been described and illustrated in connection with a preferred embodiment, it is obvious that modifications and variations may be resorted to without departing from the spirit of the inven- 'tion as those skilled in this art will readily understand. lSuch modifications and variations are considered to be within the purview and scope of the present invention as defined by the appended claims.

What is claimed is:

Apparatus for gripping an elongated vertical member, comprising a unitary body, a pair of first parallel shafts mounted on the body and disposed in a common horizontal plane, an arm mounted on each first shaft for rotation relative to the body about the axis of the shaft, a pair of second shafts parallel to the first shafts and mounted one on the end of each arm remote from the associated first shafts, a backup member mounted on each second shaft for rotation relative to the associated arm about the axis of the associated second shaft, the backup members and the body having horizontal surfaces in direct contact with each other when all four said axes are coplanar, the backup members having opposed confronting surfaces which are inclined downward toward each other when said horizontal surfaces are in contact with each other, and a slip mounted for vertical movement on and relative to each backup member, each slip comprising a wedge disposed along said opposed confronting surface of its associated backup member and progressively decreasing downward in thickness, all the vertical components of thrust of an elongated vertical member carried by the apparatus being transmitted from the slips throughthe backup members and through said horizontal surfaces to said body, and all the horizontal components of thrust of an elongated vertical member carried by the apparatus. being transmitted from the slips through the backup members and through the second shafts and lengthwise along the arms and through the first shafts to said body.

References Cited in the file of this patent UNITED STATES PATENTS 327,944 Griscom Oct. 6, 1885 713,738 Broden Nov. 18, 1902 950,275 Butler Feb. 22, 1910 1,460,401 Benckenstein July 3, 1923 1,666,621 Greenwood Apr. 17, 1928 1,721,024 Krell et al July 16, 1929 1,883,073 Stone Oct. 18, 1932 2,319,016 Taylor May 11, 1943 2,700,201 Bannister Jan. 25, 1955-

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