United States Patent [19]
`McKay
`
`[54]
`
`[76]
`
`FIBERGLASS OIL WELL SUCKER ROD
`Inventor: (cid:9) Angus T. McKay, 1105 D'Amico Dr.,
`Chicago Heights, Ill. 60411
`
`[21] Appl. No.: 236,664
`Feb. 23, 1981
`[22] Filed: (cid:9)
`Int. C1.3
`[51]
`[52] U.S. Cl. (cid:9)
`[58] Field of Search (cid:9)
`
`F16B 11/00
`
`403/13; 403/268
`
` 403/268, 267, 266, 265,
`403/368, 13
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`2,212,153 8/1940 Eaton et al. (cid:9)
`2,322,587 6/1943 Payne (cid:9)
`
`3,018,140 1/1962 Portz et al. (cid:9)
`
`4,190,479 2/1980 Smith (cid:9)
`
`4,315,699 2/1982 Lusk (cid:9)
`
`FOREIGN PATENT DOCUMENTS
`403/267
`681550 10/1952 United Kingdom
`285/DIG. 16
`
`289249 12/1970 U.S.S.R. (cid:9)
`Primary Examiner—Andrew V. Kundrat
`Attorney, Agent, or Firm—Warren H. Kintzinger
`
`403/227
`285/DIG. 16
`403/268 X
`156/294
`403/361
`
`[11] (cid:9)
`
`[45] (cid:9)
`
`4,401,396
`Aug. 30, 1983
`
`ABSTRACT
`[57] (cid:9)
`A fiberglass oil well sucker rod with a male threaded
`fitting bonded to each end of a fiberglass rod so that the
`fiberglass sucker rod may be threadedly connected
`through interconnecting female threaded couplings in a
`well string to other like rods of the same or different
`lengths and/or to a down-the-well pump and to well
`string drive and pump drive equipment at the top of the
`well. Fittings on ends of a fiberglass rod include an
`annular shoulder that holds a centering ring for the rod,
`four tapered pocket steps, and finally, a centering
`pocket beyond the innermost step.The taper of tapered
`pocket closest to the fitting opening is more shallow
`than the taper of the following tapered pockets with the
`minor diameter of each taper having a radiused en-
`trance tangential to the angle of the taper of the pocket
`to relieve stress on the epoxy used bonded to the rod
`and filling space between the rod and the fitting. Rather
`than the assembly being completely bonded together a
`mold release agent is coated on the interior of each
`fitting and the epoxy bonded to the rod with the wedges
`formed thereof holding the rod ends within the opposite
`end fittings.
`
`4 Claims, 3 Drawing Figures
`
`/7
`
`Petitioners' Exhibit 1012
`John Crane v. Finalrod
`IPR2016-01786
`Page 1 of 4
`
`(cid:9)
`(cid:9)
`(cid:9)
`

`
`U.S. Patent
`
`FIG. I
`
`Aug. 30, 1983 (cid:9)
`FIG. 2
`
`4,401,396
`
`13
`
`/0
`
`FIG. 3 (cid:9)
`
`/9
`
`/4
`
`/6
`
`26
`25'
`230
`12----
`24D
`23C
`
`24 C
`
`15
`23B
`
`248
`
`23A
`
`24 A
`20
`
`17
`
`2/
`
`22
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`Page 2 of 4
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`

`
`1
`
`FIBERGLASS OIL WELL SUCKER ROD
`
`4,401,396 (cid:9)
`
`2
`A further object is to provide an oil well sucker rod
`more resilient and adequately strong yet lighter than
`pre-existing steel sucker rods.
`Another object is to increase oil pumping production
`from wells at a savings in equipment costs and with
`significant power savings.
`Features of the invention useful in accomplishing the
`above objects include, in a fiberglass oil well sucker rod,
`a fiberglass rod having metal fittings at each end that
`may be threadedly connected through interconnecting
`threaded couplings to other like sucker rods of the same
`or different lengths and/or to a down-the-well pump
`and to well string drive and pump drive equipment at
`the top of the well. The fittings on ends of a fiberglass
`sucker rod include an annular shouldered pocket hold-
`ing a centering ring for the rod that also projects for a
`protective distance from the rod end of the fitting, four
`tapered pocket steps with at least the closest tapered
`pocket to the rod entrance end having a more shallow
`taper than the next tapered pocket, and finally, a center-
`ing pocket beyond the innermost step. The minor diam-
`eter of each tapered pocket has a radiused entrance
`tangential to the angle of the taper of the respective
`pockets to relieve stress on the epoxy (or its equivalent)
`used bonded to the rod and filling space between the
`rod and each fitting. Rather than the assembly being
`completely bonded together a mold release agent is
`coated on the interior of each fitting and the epoxy
`bonded to the rod with the wedges formed thereof
`holding the rod end within the opposite end fittings.
`A specific embodiment representing what is presently
`regarded as the best mode of carrying out the invention
`is illustrated in the accompanying drawing.
`
`In the drawing:
`FIG. 1 represents a perspective view of an oil well
`sucker rod equipped with duplicate male fittings on the
`opposite ends;
`FIG. 2, a partially cut away and sectioned view of the
`sucker rod of FIG. 1 showing additional detail of the
`rod end fitting and rod end to fitting interconnection
`detail; and
`FIG. 3, a perspective view of the centering ring used
`for centering of the rod relative to the interior of a
`fitting and to shield the rod from tool impact damage
`for a distance from the open end of the fittings.
`
`REFERRING TO THE DRAWING:
`An oil well sucker rod 10, as shown in FIGS. 1 and 2,
`is a fiberglass rod 11 with metal male fittings 12 having
`a threaded extension 13 and a tool engaging section
`with flats 14 mounted on each end. Each metal male
`fitting 12 has an opening 15 into which a fiberglass rod
`11 is inserted with rod tapered end 16 inserted through
`length 17 of the fitting opening 15. A centering ring 18
`(a nylon ring with an I.D. approximately 0.002 inches
`smaller than the O.D. of the fiberglass rod 11 inserted
`therethrough) has a tapered shoulder 19 centering the
`ring 18 in its holding pocket 20 in the fitting opening 15.
`Centering ring 18 is provided with an epoxy flow relief
`passage 21 and has an inner wall 22 I.D. approximately
`0.002 inches less than the O.D. of rod 11.
`There are four successive tapered pockets 23A, 23B,
`23C and 23D within opening 15 and the minor diameter
`of each tapered pocket has a radiused entrance 24A,
`24B, 24C and 24D, respectively, tangential to the angle
`of the taper of the respective pockets to relieve stress on
`the epoxy (or its equivalent) used bonded to the rod and
`
`10
`
`15
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`20
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`25
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`30
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`35
`
`40
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`45
`
`50
`
`This invention relates in general to fiberglass sucker
`rods for well strings in oil wells and, more particularly, 5
`to effective, improved fiberglass rod to metal fitting end
`interconnect with epoxy (bonding material) used
`bonded to the rod and filling space between the rod and
`the fitting.
`Fiberglass sucker rods properly designed, installed
`and used significantly increase oil production, reduce
`lifting costs and reduce capital expenditures for beam
`type pumping systems. Fiberglass rods, made with fi-
`berglass in a polyester resin base, feature lightweight
`and high strength and offer many advantages over con-
`ventional steel sucker rods including increased oil pro-
`duction. Fiberglass sucker rods can be pumped at
`speeds that would overstress heavy steel rod strings
`with lightweight fiberglass rods reducing loads on the
`drive gear box, structure and prime mover such as to
`permit faster operation. Reduced pumping unit loading
`through use of fiberglass strings permits use of the maxi-
`mum stroke length setting and also pumping at greater
`depths where steel string stress level and/or pumping
`unit loading is a restriction. It is also of interest that the
`increased elasticity of a fiberglass sucker rod string over
`a steel sucker rod string yields a longer, more effective
`pump stroke, particularly if the sucker rod string is
`"tuned" to the specific well installation. Initial lifting
`equipment and field maintenance costs are reduced in
`that string body partings due to corrosion is eliminated
`since fiberglass rod bodies do not corrode in an oil well
`environment, and partings due to stress and stress corro-
`sion are minimized with relative light weight of fiber-
`glass rod strings reducing the rod string stress levels.
`The weight reduction in sucker rod strings saves on
`electrical energy consumption per barrel of oil lifted,
`and capital equipment costs can be reduced in that beam
`pumping systems can be designed around smaller pump-
`ing units and less powerful prime movers.
`Fiberglass sucker rods yielding all of these advan-
`tages must be designed to be compatible with standard
`tools used in the oil production industry with a require-
`ment for end fittings on the ends of the fiberglass sucker
`rods compatible with standard elevators, rod wrenches
`and power tongs. While the many advantages presented
`may be attained through the use of fiberglass sucker
`rods, a major problem in the past has been to provide a
`safe, secure interconnection between the fittings and the
`ends of the individual rods. Fiberglass is just difficult to
`grab a hold of and hold securely and it is very important
`that the structure have such integrity as to substantially
`eliminate fiberglass rod-to-end fitting parting in fiber-
`glass sucker rods used in a well string when used within 55
`predetermined design capacities. Damaging stress con-
`centrations in the area of rod entry into a fitting and
`within the rod end fittings must be minimized, as well as
`tool impact damage to a rod adjacent entry into a fit-
`ting. (cid:9)
`It is, therefore, a principal object of this invention to
`provide a fiberglass sucker rod with metal fittings on
`opposite ends that can be readily installed in an oil well
`string and used within design limits without end fitting
`to fiberglass rod parting. (cid:9)
`Another object is to provide such fiberglass sucker
`rods having excellent non-corrosive and long service
`life characteristics.
`
`60
`
`65
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`Page 3 of 4
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`(cid:9)
`

`
`4,401,396
`
`10 (cid:9)
`
`20
`
`3
`filling space between the rod 11 and each fitting 12. The
`four steps or tapers in the fitting opening 15 consist of at
`least two different angles with the pocket 23A closest to
`the rod entrance end of opening 15 being the shallowest
`taper at approximately a 2.5° taper and the following
`pockets 23B, 23C and 23D having approximately a 5.5°
`taper in the embodiment shown. In another embodi-
`ment, not shown, the four tapered pocket steps have
`successively steeper tapers from pocket 23A, being the
`shallowest at approximately a 2.5° taper, and the follow-
`ing pockets 23 being successively approximately 3.5°,
`4.5° and 5.5° tapers, respectively. The last tapered
`pocket 23D ends with shoulder 25 and centering pocket
`26 is extended therebeyond.
`The rod tapered end 16 is a 2-inch long 5° taper
`ground on each end of each fiberglass rod 11 to readily
`facilitate insertion of the rod 11 into nylon centering
`ring 18. Approximately 48 inch of each end of fiberglass
`rod 11 is sandblasted using a 14-inch sandblasting nozzle
`and 50 grit sand to optimize bonding of epoxy and the
`epoxy wedges filling tapered pockets 23A, 23B, 23C
`and 23D to the respective end of rod 11. Before each
`fitting 12 receives epoxy in opening 15 the opening
`internal surfaces are coated with a mold release agent
`particularly through the range of tapered pockets
`23A-23D to allow epoxy wedges cured in tapered
`pockets 23A-23D to move forward ever so slightly
`against the tapered shoulders of the pockets 23A-23D.
`When a rod 11 is prepared for insertion into a fitting 12
`and the fitting is prepared to receive a rod end, a prede-
`termined quantity of epoxy in fluid form is placed in
`opening 15, and with centering ring 18 inserted with
`tapered shoulder 19 in holding pocket 20, the rod end is
`inserted through the centering ring 18 and fully into the
`opening 15 and centering pocket 26. The centering ring
`18 and centering pocket 26 center the fiberglass rod 11
`in fitting 12 almost perfectly to in effect optimally mini-
`mize, if not eliminate, any likelihood of stress risers
`occurring because of uneven loading from rods 11 not
`being parallel to the center line of a fitting 12 connected
`thereto. As an end of a rod 11 is fully inserted into
`opening 15 of a fitting 12 the epoxy in fluid form placed
`therein flows to fill the spaces between the rod end and
`fitting 12 with any excess to the proper amount of epoxy
`flowing into epoxy flow relief passage 21. The rod 11
`with its end fittings 12 is then placed in an oven for
`epoxy curing, baked at 300° for 2.1 hours, allowed to
`cool to room temperature and then placed in a machine
`for tensile loading (running to approximately 22,000
`pounds tensile loading). With mold release having been
`used on the inner surface of fitting opening 15 allows
`the epoxy wedges to move forward minutely, if they
`move forward at all, completing the joint. In addition to
`the rod 11 centering function provided by centering
`ring 18 in extending approximately one inch out of
`opening 15 it provides a shield for the rod 11 from tool
`impact damage for a distance from the open end of each
`fitting 12. Centering rings 18 made from nylon are ex-
`cellent in providing such useful functional advantages.
`The fiberglass rod 11 to fitting 12 interconnection is
`excellent, particularly with four tapered wedge pockets,
`with the first being less tapered than the following.
`Each wedge minimum diameter being properly radi-
`used along with uniform annular thickness through
`cured epoxy with properly centered relation between
`rod end and fitting minimizes stress concentration prob-
`lems, particularly with properly centered alignment
`through rod to fitting interconnect reducing the possi-
`
`4
`bility of uneven loading. This rod has a higher inplane
`shear value and may as a result be of smaller diameter to
`in turn reduce loading in a well string still further.
`Whereas, this invention is herein illustrated and de-
`5 scribed with respect to a plurality of embodiments
`thereof, it should be realized that various changes may
`be made without departing from the essential contribu-
`tions to the art made by the teachings hereof.
`I claim:
`1. A fiberglass sucker rod for well strings in a well
`such as an oil well including: a fiberglass rod cut to
`length; fittings each with a rod end receiving opening
`mounted on opposite ends of said fiberglass rod; said
`rod end receiving openings in said fittings having a
`15 successive positioned plurality of tapered annular pock-
`ets; space between a rod end and the walls of said rod
`end receiving opening being filled by a hardened bond-
`ing matter, formerly in fluid form at time of rod end to
`fitting assembly; and said hardened bonding matter
`forming tapered annular wedges each bonded to said
`rod and generally in the shape of the respective tapered
`pockets forming molds for the bonding matter con-
`tained therein as it hardens to the solid state; and with
`25 the tapered annular pocket and the tapered annular
`wedge contained therein closest to the rod entrance end
`of said fitting opening having a more shallow taper than
`the taper of following tapered pockets and the tapered
`annular wedges contained therein; wherein the outer
`30 diameter of the fiberglass rod throughout the distance
`of said successively positioned plurality of tapered an-
`nular pockets is of less diameter than the minor diameter
`of each of said successively positioned plurality of ta-
`pered annular pockets; and with said annular tapered
`35 wedges interconnected by hardened bonding matter;
`each of said successively positioned plurality of tapered
`annular pockets at the minor diameter thereof has an
`annular radiused entrance tangential to the angle of the
`taper of the pocket to relieve stress in hardened bonding
`40 matter shaped thereby; centering means contributes to
`properly centered alignment between the rod and fit-
`ting through each rod to fitting interconnect; said cen-
`tering means includes a centering ring seated in an annu-
`lar shoulder at the rod entrance of said fitting opening;
`45 said centering ring projects for a protective distance
`from the rod end of the fitting to protect from tool
`impact damage; and, wherein said centering ring is
`provided with a bonding agent relief passage to receive
`excess flow of bonding agent in the fluid form as a rod
`50 end and fitting are assembled together.
`2. The sucker rod of claim 1, wherein said centering
`means also includes a centering pocket beyond the in-
`nermost step remote from the rod entrance end of said
`fitting opening.
`3. The sucker rod of claim 1, wherein the wall sur-
`faces of said tapered annular pockets in the rod end
`receiving openings in said fittings are coated with a
`mold release material prior to bonding matter in fluid
`form being placed in said rod end receiving openings;
`60 and with said tapered annular wedges while bonded to
`rod ends of said fiberglass rod being free of bonded
`attachment to the wall surfaces of said tapered annular
`pockets.
`4. The sucker rod of claim 3, wherein said tapered
`65 annular wedges are tapered larger diameter to smaller
`diameter toward the rod entrance end of said fitting
`opening.
`
`55 (cid:9)
`
`Page 4 of 4