(cid:9) (cid:9)
`
`(51)
`
`Int. Cl.
`B29C 65/00 (cid:9)
`B29C 47/00 (cid:9)
`B32B 37/00 (cid:9)
`C08J 5/00 (cid:9)
`B25G 3/34 (cid:9)
`F16B 11/00 (cid:9)
`F16B 12/04 (cid:9)
`F16L 13/00 (cid:9)
`GO5G 1/12 (cid:9)
`(52) U.S. Cl.
`
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
` 156/289; 156/244.13; 156/293;
`156/307.1; 403/268; 403/361
`(58) Field of Classification Search (cid:9)
` 156/91,
`156/153, 157, 158, 242, 244.11, 244.13,
`156/244.24, 278, 281, 289, 293, 294, 296,
`156/303.1, 304.1, 304.2, 304.3, 304.6, 307.1,
`156/307.3, 307.5, 307.7; 403/265, 267, 268,
`403/269, 345, 361
`See application file for complete search history.
`
`(12) United States Patent (cid:9)
`Rutledge, Sr. et al. (cid:9)
`
`11111111111111111111111111f1111011,111)!II111111111111111111111111111
`
`(10) Patent No.: (cid:9)
`(45) Date of Patent: (cid:9)
`
`US 8,062,463 B2
`Nov. 22, 2011
`
`(54)
`
`METHOD OF ASSEMBLING SUCKER RODS
`AND END FITTINGS
`
`(75)
`
`Inventors: Russell P. Rutledge, Sr., Big Spring, TX
`(US); Russell P. Rutledge, Jr., Big
`Spring, TX (US); Richard D. Burchett,
`Coahoma, TX (US); Floyd L.
`Brownfield, Big Spring, TX (US)
`
`(73)
`
`Assignee: Fiberod, Inc., Morton Grove, IL (US)
`
`(*)
`
`Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 892 days.
`
`(21) Appl. No.: 11/715,087
`
`(22) Filed: (cid:9)
`
`(65)
`
`Mar. 5, 2007
`
`Prior Publication Data
`
`US 2008/0217914 Al (cid:9)
`
`Sep. 11, 2008
`
`(56) (cid:9)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`3,168,340 A
`2/1965 Howard
`4,315,699 A
`2/1982 Lusk
`4,360,288 A
`11/1982 Rutledge et al.
`4,401,396 A *
`8/1983 McKay (cid:9)
`4,430,018 A *
`2/1984 Fischer (cid:9)
`4,475,839 A
`10/1984 Strandberg
`4,563,391 A
`1/1986
`Tanner et al. (cid:9)
`4,597,688 A
`7/1986
`Pagan (cid:9)
`4,662,774 A
`5/1987
`Morrow
`RE32,865 E
`2/1989
`Rutledge et al.
`4,822,201 A
`4/1989 Iwasaki et al.
`4,919,560 A
`4/1990 Rutledge et al.
`(Continued)
`
`*
`*
`
`OTHER PUBLICATIONS
`
`
`
`
`
`
`
`403/13
`403/268
`
`428/365
`403/265
`
`U.S. Patent & Trademark Office, Office Action in U.S. Appl. No.
`11/715,088 (Dec. 30, 2010).
`
`Primary Examiner — Philip C Tucker
`Assistant Examiner — Brian R Slawski
`(74) Attorney, Agent, or Firm — Leydig, Voit & Mayer, Ltd.
`
`(57) (cid:9)
`
`ABSTRACT
`
`An improved design and a method of assembly of end fittings
`to sucker rods which may be of conventional length or con-
`tinuous sucker rods is described herein. The end fittings and
`rods are assembled so as to form wedges which enhance the
`connectability of the end fitting to the rod, and further, the
`wedge or wedges approach the rod asymptotically so as to
`avoid any abrupt discontinuities in the wedge or wedges thus
`substantially eliminating stress concentration areas and
`potential failure areas in the rod. The assembly method pro-
`vides for integrity in the rod to end fitting assembly to pro-
`mote longer connection life and fewer shop rejections and
`field failures.
`
`12 Claims, 4 Drawing Sheets
`
`Petitioners' Exhibit 1016
`John Crane v. Finalrod
`IPR2016-01786
`Page 1 of 15
`
`(cid:9)
`

`
`US 8,062,463 B2
`Page 2
`
`U.S. PATENT DOCUMENTS
`5,088,638 A *
`2/1992 Karaev et al. (cid:9)
`5,253,946 A
`10/1993 Watkins
`6,193,431 Bl * 2/2001 Rutledge (cid:9)
`
`
`
`
`
`228/112.1 (cid:9)
`
`403/268 (cid:9)
`
`6,886,484 B2 * 5/2005 Thomas (cid:9)
`2005/0000689 Al * 1/2005 Peleanu et al. (cid:9)
`2008/0217023 Al (cid:9)
`9/2008 Rutledge
`* cited by examiner
`
` 114/108
` 166/279
`
`Page 2 of 15
`
`(cid:9)
`(cid:9)
`(cid:9)
`

`
`U.S. Patent (cid:9)
`
`Nov. 22, 2011 (cid:9)
`
`Sheet 1 of 4
`
`US 8,062,463 B2
`
`FIG. 1
`
`FIG. 1A
`
`Page 3 of 15
`
`(cid:9)
`

`
`U.S. Patent (cid:9)
`
`Nov. 22, 2011 (cid:9)
`
`Sheet 2 of 4 (cid:9)
`
`US 8,062,463 B2
`
`106
`
`127
`
`100
`i
`105
`
`110
`1
`115
`I
`117
`
`119
`1
`121
`
`125
`
`130
`1
`132
`i
`134
`1
`138
`I
`140
`1
`142
`
`144
`i
`147
`1
`150
`1
`155
`
`FIG. 2
`
`66
`
`66
`
`60 -
`
`FIG. 3
`
`Page 4 of 15
`
`

`
`U.S. Patent (cid:9)
`
`Nov. 22, 2011 (cid:9)
`
`Sheet 3 of 4 (cid:9)
`
`US 8,062,463 B2
`
`C
`
`c-30
`
`72
`
`7
`
`FIG. 4A
`
`FIG. 4
`
`Page 5 of 15
`
`

`
`lualud °Sil
`
`LLOZ `ZZ *A
`0NI
`
`17 JO 17 JamiS
`
`Zll £917t90`8 Sf1
`
`FIG. 7
`
`14
`
`10
`
`FIG. 6
`
`50
`
`46
`
`(-45 (cid:9)
`
`43 -\ (cid:9)
`
`42-
`
`
`
`40
`
`FIG. 5A
`
`FIG. 5
`
`112
`
`16
`
`Page 6 of 15
`
`

`
`1
`METHOD OF ASSEMBLING SUCKER RODS
`AND END FITTINGS
`
`RELATED APPLICATION
`
`This patent application is related to U.S. patent application
`Ser. No. 11/715,085, filed Mar. 5, 2007, entitled "Continuous
`Sucker Rod and Method of Using Same," issued as U.S. Pat.
`No. 7,730,938, and to U.S. application Ser. No. 12/794,298,
`filed Jun. 4, 2010 which is a divisional of U.S. application Ser.
`No. 11/715,085, and is related to U.S. patent application Ser.
`No. 11/715,088, filed Mar. 5, 2007, entitled "Improved
`Sucker Rod End Fittings and Method of Using Same."
`
`TECHNICAL FIELD
`
`The present invention relates to oilfield production, and
`more particularly, to the assembly of fiberglass or composite
`sucker rods including the end-fittings in conjunction with
`downhole pumps and surface located pump actuation sys-
`tems.
`
`BRIEF DESCRIPTION OF DRAWINGS
`
`For a further understanding of the nature and objects of the
`present invention, reference should be had to the following
`detailed description, taken in conjunction with the accompa-
`nying drawings, in which like elements are given the same or
`analogous reference numbers.
`FIG. 1 illustrates a side elevated view partially in cross-
`section of a wellbore having a sucker rod string attached
`between a pump and a pump drive according to the present
`invention;
`FIG. 1A illustrates a side elevated view partially in cross-
`section of a wellbore having a sucker rod string comprising
`more than one rod attached between a pump and a pump drive
`according to the present invention;
`FIG. 2 illustrates a flow chart of assembling a sucker rod
`and end fitting;
`FIG. 3 illustrates a partial side view of an embodiment of a
`sucker rod further illustrating gauge marks for assembly
`according to the present invention;
`FIG. 4 illustrates a side elevated view, partially in cross-
`section, of a sucker rod end fitting in accordance with the
`present invention;
`FIG. 4A illustrates a side elevated cross-sectional view of
`an improved sucker rod end fitting in accordance with the
`present invention;
`FIG. 5 illustrates a side view partially in cross-section of a
`portion of a sucker rod according to the present invention;
`FIG. SA illustrates a bottom cross-sectional view of a
`sucker rod outer shape in accordance with the present inven-
`tion;
`FIG. 6 illustrates, in flow chart form, the process for manu-
`facturing a continuous sucker rod in accordance with the
`present invention; and
`FIG. 7 illustrates a side view partially in cross-section of an
`alternative embodiment of a portion of a sucker rod according
`to the present invention.
`
`DETAILED DESCRIPTION OF EMBODIMENTS
`OF THE INVENTION
`
`It is well known in the art to use sucker rods to actuate a
`downhole pump to recover oil from a wellbore. Typically, a
`series of sucker rods are connected end to end to form a sucker
`rod string, which extends from the pump drive 10 to the pump
`
`US 8,062,463 B2
`
`20 (cid:9)
`
`2
`14 (FIG. 1). It should be appreciated that pump drive 10 is
`typically a pump jack (i.e. a beam pump system) or other
`known pump drive. Further, downhole pump 14 is typically a
`conventional pump well known in the art. It should be appre-
`5 ciated that although fiberglass or composite sucker rods are
`light weight, they are typically connected by metallic end
`fittings 30 which add to the weight of the string and can be a
`considerable factor in a very deep wellbore as the pump drive
`must overcome the weight of the sucker rod string, including
`10 the metallic end fittings 30 in order to acuate the downhole
`pump 14.
`It should be appreciated that the sucker rod string can be
`made up of many rods that are approximately thirty-seven
`(37) feet in length, the string can comprise one single con-
`15 tinuous rod, or a few continuous rods which can be hundreds
`of feet in length or even a thousand or more feet in length.
`Regardless of the length of the sucker rod, it is preferably
`assembled, as described herein, with an end-fitting 30 as
`illustrated in FIG. 4 or 4A.
`FIG. 1 illustrates a typical pumping system wherein the
`pump drive 10 is a conventional beam pump or pump jack and
`is connected to a downhole pump 14 through the sucker rod
`string 12a inserted into wellbore 8. The sucker rod string 12a
`can comprise a continuous sucker rod which extends from
`25 downhole pump 14 to pump drive 10, a series of connected
`continuous rods, a series of conventional length rods con-
`nected together, or any combination thereof Preferably, the
`sucker rod 12 is a fiberglass or composite rod. It should be
`understood that, as described herein, the sucker rod string 12a
`30 may be the same as the continuous sucker rod 12 when the
`continuous sucker rod 12 is a one piece rod that extends
`substantially between the pump drive 10 and the sub-surface
`pump 14.
`Referring now to FIGS. 2 and 3, typically, a sucker rod 12
`35 and its corresponding end fittings 30 are separately prepared,
`assembled together, and tested for the integrity of the end
`fitting 30 to rod 12 connection. FIG. 2 illustrates a flow chart
`corresponding to the steps of preparing and assembling the
`end fitting 30 and the rod 12. FIG. 3 illustrates the rod 12 and
`40 corresponding elements described hereinbelow. When the
`end fittings 30 are manufactured 100, they are preferably
`inspected 105, per in-house quality control for proper toler-
`ancing. It should be appreciated that proper tolerancing refers
`to the particular design specifications to which the end fitting
`45 30 is manufactured to. It should further be understood that
`quality control inspection, of the tolerances, can also be per-
`formed at the manufacturing facility, or by third party inspec-
`tors. If the end fittings 30 pass the inspection criteria, they are
`advanced to the next step 110. The dimensionally acceptable
`so end fittings 30 may also be placed in inventory for future
`manufacturing needs. Typically, if the end fittings 30 do not
`pass the dimensional and/or tolerancing inspection they may
`be returned 106 to the manufacturer, scraped, repaired (i.e.
`welded and or machined so as to meet the required dimen-
`55 sional/tolerancing criteria) or any combination thereof. It
`should be understood, by those in the art, that the dimen-
`sional/tolerancing inspection can be performed on each indi-
`vidual end fitting 30 or on some pre-determined portion of
`end fittings selected by some statistical sampling method.
`Next 110 the end fittings 30 are cleaned. The cleaning
`operation preferably comprises at least one wash. However,
`the end fittings 30 may be cleaned by any variety of conven-
`tional methods to remove dirt, scale, oil/grease, or other con-
`taminants that may have settled on the surfaces of the end
`65 fitting 30. It should be appreciated that the cleaning step 110
`may also include the detection and removal of burrs, metal
`shavings, or other abnormalities left from manufacturing. It
`
`60 (cid:9)
`
`Page 7 of 15
`
`

`
`US 8,062,463 B2
`
`4
`3
`should be further appreciated that the cleaning step 110 can be (cid:9)
`placement. The marks 62, 64 can be made in a variety of
`manually or automatically performed. (cid:9)
`conventional manners but it is preferable that the mark 62, 64
`After the cleaning step 110, the end fittings 30 are posi- (cid:9)
`is on the rod 12 surface, such as but not limited to, a paint
`tioned, at step 115, so as to allow the introduction of a mold
`mark or ink mark. Although light scribe marks may be accept-
`release agent into the end fitting 30. It should be understood 5 able, care should be taken not to deeply scratch of gouge the
`that the mold release agent can be a variety of conventional
`surface and the light scribe marks may be difficult to see
`mold release agents. The mold release agent will prevent the
`during other operations. Further, because at least one of the
`bonding of the end fitting 30 metal material with the adhesive (cid:9)
`gauge marks 62, 64 must be visible after a heat cure step, the
`that is used to connect the end fitting 30 with the rod end 60. (cid:9)
`mark 62, 64 must be of a type to withstand higher tempera-
`It will be more fully understood, as discussed hereinbelow, 10 tures. The accepted rod bodies 12 are preferably moved to a
`that this novel method of assembly does not rely on the (cid:9)
`sanding area 132.
`chemical adhesion of the end fitting 30 to the rod 12 but rather
`Preferably, the rods 12 are sanded on the ends 60, that will
`a mechanical action. Thus, the purpose of the mold release (cid:9)
`accept the end fittings 30. In one embodiment, the rod ends 60
`agent will become apparent hereinbelow. (cid:9)
`are sanded in a machine. In another embodiment the rod ends
`Preferably, to apply the mold release agent, the cleaned end 15 60 are sand blasted and in yet another embodiment the sand-
`fittings 30 are turned upside down, so that the mold release
`ing is done manually. It should be appreciated that the step of
`agent can be poured into the end fitting 30. Preferably, the (cid:9)
`machine sanding is more accurate and preferably results in a
`entire end fitting 30 is filled with the mold release agent and
`lower reject rate after the assembly of the rod end 60 and the
`allowed to stand 117. Preferably, the end fittings 30 are left for (cid:9)
`end fitting 30, both during inspection and during field opera-
`about 3 or 4 minutes. However, the standing time may vary 2o tion. It should further be appreciated that the machine sanding
`and should not be viewed as a limitation herein. It is foresee- (cid:9)
`can be further carried out by full automation or by a combi-
`able, that as the assembly becomes more automated, more (cid:9)
`nation of automation and manual sanding. The combination
`technically advanced, and as different mold release agents are (cid:9)
`of automation and manual sanding comprises a machine
`developed and tested, the standing time may vary to a more (cid:9)
`which rotates the rod bodies 12, about their longitudinal axis,
`precise time and other steps may be integrated such as, but not 25 and the ends 60 are manually sanded. Preferably, the manual
`limited to, spray applications, heated applications, cold appli- (cid:9)
`sanding, whether aided by a machine or completely per-
`cations, or any combination therein. After the standing time, (cid:9)
`formed manually, is done using a 50 grit sandpaper. However,
`the mold release agent is poured out of the end fitting 30. It
`it should be appreciated that the grit of sandpaper can be
`should be appreciated that if some type of spray application is (cid:9)
`varied. Preferably, the sanding step 132 will allow for a better
`utilized, the pouring out and/our the standing time may 30 more thorough bonding between the adhesive and the rod
`body 12. It should be apparent, from the description above,
`change or be eliminated. It should be understood, that after
`the mold release agent has been poured out, the end fitting 30
`and as further detailed below, that the adhesive must bond
`should be allowed to stand so as to allow substantially all the (cid:9)
`with the rod end 60 but should not bond with the end fitting
`remaining release agent to dry. (cid:9)
`30.
`After the rod ends 60 have been sanded 132, the sanded
`After the access mold release agent has been poured out 35 (cid:9)
`119, the coated end-fittings 30 are preferably placed into a (cid:9)
`ends 60 are preferably cleaned 134 to provide a good surface
`heated environment 121 such as, but not limited to, an oven. (cid:9)
`for adhesion. Preferably, the sanded ends 60 are washed with
`The oven can be a conventional oven used for metal treatment (cid:9)
`alcohol. However, a variety of conventional cleaners or
`such as stress relieving or heat treatment. Preferably, the end
`chemicals can be utilized as long as they do not interfere with
`fitting 30 will remain in the heated environment, such as an 40 nor compromise the base material of the rod body 12. After
`the ends 60 have been cleaned and have dried, the rod bodies
`oven until it reaches a temperature of about 150 degrees F. It
`12 are preferably ready for the step of assembling the rod
`should be understood that the exact temperature may vary due
`to the mold release agent's manufacturer's curing recommen- (cid:9)
`body 12 and the end fitting 30.
`The assembly step 138 comprises filling the previously
`dations, the exact type of mold release, the type of material
`used in manufacturing the end fitting 30, or other factors 45 prepared end fittings 30 with a pre-determined amount of
`relating to the curing process. After the curing, the end fittings (cid:9)
`adhesive. It should be appreciated that the adhesive is of a
`30 can be moved to a staging area or into an inventory storage (cid:9)
`conventional kind to bond to the material of the rod body 12.
`area in preparation of assembly with a sucker rod end 60. (cid:9)
`However, other adhesives may be acceptable and the selec-
`The sucker rods 12, onto which the end fittings 30 will be (cid:9)
`tion of a particular adhesive should not be viewed as a limi-
`assembled, are inspected 125 after being formed. It should be 50 tation herein. Once the adhesive has been placed in the end
`fitting 30, the end fitting 30 is placed onto the rod body end 60.
`appreciated that the preferable manner of manufacturing the
`sucker rod 12 is through pulltrusion. However, other methods
`Preferably, the end fittings 30 are applied manually and
`of manufacturing are visualized and should not be viewed as (cid:9)
`then properly positioned on the rod end 60 by means of a
`a limitation thereof. Preferably, the rejected rod bodies 12 are (cid:9)
`manual tool. Preferably, the end fittings 30 are positioned so
`separated for scrap or repair. Preferably, the next step 130 is to 55 as to be aligned with the second gauge mark 64 to ensure that
`properly gauge and mark the rod body ends 60, which will be
`it has bottomed out, i.e. that the rod end 60 is fully inserted
`receiving the end fittings 30. Preferably, two gauge marks are
`into the end fitting 30 yet still creating the necessary cavity 24,
`made, on each end 60 to be assembled with an end fitting 30. (cid:9)
`26 (see FIG. 4) between the internal surface of the end fitting
`One mark 62 is to indicate the length of the area to be sanded
`30 and the external surface of the rod end. It has been found
`66. The second gauge mark 64 is to indicate the proper posi- 60 that if the end fittings 30 are rotated on to the rod end 60, the
`tion of the end fitting 30 after it has been placed onto the (cid:9)
`adhesive is more evenly distributed between the rod end 60
`sanded end 60 as explained in more detail hereinbelow. It (cid:9)
`surface and the internal surface of the end fitting 30. Prefer-
`should be appreciated that the position of the marks is a (cid:9)
`ably, the assembly tool allows the end fitting 30 to be accu-
`function of the rod body 12 diameter and the size of the end
`rately and repeatedly positioned for each application. It
`fitting 30, which will be applied. The placement of the gauge 65 should be appreciated that other methods of placing the end
`marks 62, 64 can be determined by measuring or by the use of
`fitting 30 onto the rod end 60 are possible. These may include,
`a gauge to increase repeatability and accuracy of the mark
`but are not limited to, the use of a conventional drill, such as
`
`Page 8 of 15
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`(cid:9)
`

`
`US 8,062,463 B2
`
`5
`a pneumatic, hydraulic, or air drill, for high speed rotation,
`using a machine to rotate either or both the rod body 12 and
`the end fitting 30, or a variety of other means of which would
`allow for the proper positioning of the end fitting 30, with
`respect to the rod end 60, while maintaining a thorough and
`even distribution of the adhesive within the cavity 24, 26
`formed between the interior of the end fitting 30 and the
`external surface of the rod end 60. It should be understood that
`in order for the rod body 12 and the end fitting 30 to remain
`assembled, through the life time of the sucker rod 12, the
`amount of and the distribution of the adhesive, in the cavity
`24, 26 formed between the interior of the end fitting 30 and the
`external surface of the rod end 60 is very important. Thus, the
`manner of placing the end fitting 30 onto the rod end 60 is very
`important. An improper assembly method, would displace
`too much adhesive, i.e. force too much adhesive out of the
`cavity 24, 26 formed between the interior of the end fitting 30
`and the external surface of the rod end 60. This over displace-
`ment, of adhesive, may result in voids, within the cured adhe-
`sive, or a lack of sufficient cured adhesive volume and thus
`compromise or destroy the mechanical bonding between the
`rod body 12 and the end fitting 30. It should be further appre-
`ciated that if the adhesive is not thoroughly and evenly dis-
`tributed or if too much adhesive has been displaced, causing
`voids or air pockets, a hydraulicing effect may result during
`curing. This hydraulicing effect pushes the end fitting 30 in a
`direction toward the end of the sanded area 66. It should be
`appreciated that such a phenomenon is not wanted as it causes
`for an improper or poor assembly between the rod body 12
`and the end fitting 30 which can result in an inspection failure
`of the rod 12 or cause a more expensive and dangerous pre-
`mature failing of the sucker rod 12 in the field. Thus, the
`second gauge mark 64, is also used to visibly inspect for any
`movement of the end fitting 30 during the curing stage. The
`purpose and advantage of this mechanical bond is explained
`in more detail herein.
`After the end fittings 30 have been properly fitted 138 onto
`the rod body ends 60, they are preferably heat cured 140 to
`assure the proper adhesion between the adhesive, in the end
`fittings 30 and the rod end 60. There are a variety of methods
`and means to heat cure the adhesive. Preferably, the adhesive,
`along with the rod end 60 and fitting 30, are preheated until
`the adhesive reaches a temperature of about 350 degrees F. It
`should be appreciated that various heating technologies are
`available to reach this pre-heat temperature very quickly. One
`such method is the use of incandescent tubes that have a
`temperature of about 1300 degrees F. The high temperature of
`the tubes coupled with a flash stone allow the adhesive tem-
`perature to reach 350 degrees F. in less than two minutes. The
`preheated rod ends 60 and end fittings 30 are then preferably
`placed in a heated environment such as, but not limited to, a
`convection oven where the 350 degree F. temperature can be
`maintained. Preferably, the rod 12 and end fitting 30 assembly
`is cured, in the heated environment for at least one hour. It
`should be understood, by those skilled in the art, that the
`curing time and temperature may vary depending on factors
`such as, but not limited to, the type/brand of adhesive, the
`material of the rod bodies 12, the material of the fittings 30,
`the size of the rod 12, the availability of the flash heating, the
`ambient temperature and humidity, and the type of heating
`environment being used.
`It should be understood that it is preferable to keep track of
`the time and temperature of the curing process. This can be
`done in a variety of ways from using sophisticated chart
`recorders or computer controls or can be much simpler by
`manually recording the time and temperature. It should be
`
`5
`
`15 (cid:9)
`
`6
`appreciated that regardless of the means of tracking the curing
`cycle, the rods 12 can be heated in batches or individually.
`At step 142, the rod bodies 12 and the attached end fittings
`30 are removed from the heating environment and are
`inspected. As briefly touched on hereinabove, one of the
`possible defects is the hydraulicing effect resulting fro air
`and/or moisture being trapped in the adhesive. This hydrau-
`licing effect will tend to force the end fitting 30 to move off of
`the rod body 12. Because of the second gauge mark 64, the
`10 end fittings 30 can be quickly checked, through a visual
`inspection, for any indication that the end fitting 30 has
`moved i.e. any separation between the second gauge mark 64
`and the end fitting 30 would indicate the movement of the end
`fitting 30.
`At step 144, the rods 12 and end fittings 30 are allowed to
`cool and then are prepared for further inspection.
`At step 147, the cooled rods 12 are pull tested to both set the
`mechanical wedge bond (explained in more detail hereinbe-
`low) between the adhesive and the end fitting 30. It should be
`20 understood that the pull test is to create and then to check the
`integrity of the mechanical bond between the rod body 12 and
`the end fitting 30. It should be further understood, that after
`curing 140 and cooling down 144, the end fittings 30 will be
`loose and capable of spinning about the rod end 60. This
`25 spinning is, at least partially, due to the bonding of the adhe-
`sive to the rod body 12 but not to the end fitting 30 due to the
`mold release applied to the interior of the end fitting 30.
`However, the fittings 30 will not come off the rod end 60 due
`to the geometry of the fitting 30 and the adhesive filled cavity
`30 24, 26 between the end of the rod 60 and the end fitting 30.
`Preferably, the pull test is conducted at a pre-determined
`pressure corresponding to the diameter of the sucker rod 12.
`As the pressure is applied, in a direction so as to move the end
`fitting 30 away from the rod body 12, the adhesive, which has
`35 bonded to the rod body 12 but not to the end fitting 30, is
`deformed, by the end fitting 30, thus creating a wedge-type
`mechanical bond between the end fitting 30 and the rod body
`12. The remaining portion of the pull test is to verify the
`integrity of the newly created mechanical bond so as to ensure
`40 that the rod 12 and the end fitting 30 are not separated during
`use. It should be appreciated, by those in the art, that after the
`pull test, the end fitting 30 will remain stationary and will not
`move nor spin about the rod body end 60.
`At step 150, the assembled sucker rods 12 and end fittings
`45 30 are visually inspected for a proper assembly. Preferably, if
`the end fittings 30 have been correctly bonded, the end fitting
`30 will move about one-eighth (1/8) of an inch in the direction
`of the pull test (i.e. the rod end 60). This movement can be
`detected visually since the adhesive, when originally applied
`so and cured, forms a "mark" 64' at the original position of the
`end fitting 30. Preferably mark 64' and mark 64 are the same
`but it should be appreciated that the gauge mark 64 may no
`longer be visible and thus the adhesive created mark 64'
`would be come the next gauge mark. This "mark" 64' is
`formed when the adhesive dried at the end of the end fitting 30
`after the original positioning of the end fitting 30. Thus, as the
`end fitting 30 moves, during the pull test, to form the cured
`adhesive into a wedge, the adhesive line becomes visible, thus
`allowing for an easy visual indication of how much the end
`60 fitting 30 actually moved.
`Next, at step 155, the assembled sucker rod 12 can be
`prepared for shipment, use, or storage. It should be appreci-
`ated that several conventional steps can be performed, such
`as, but not limited to, applying thread protectors to the end
`65 fittings 30, coating the end fittings 30 with a rust inhibitor,
`additional quality control checks or inspections, painting,
`crating, or inventorying the finished product.
`
`55 (cid:9)
`
`Page 9 of 15
`
`

`
`US 8,062,463 B2
`
`8
`7
`It should be appreciated that the above described steps do (cid:9)
`prior art designs, causing catastrophic shear failure of the
`not need to be performed in the exact sequence described. (cid:9)
`wedge. In the present invention, however, when a shock load
`occurs that creates a negative load, the wedge has the ability
`Some steps, such as the preparation of the end fitting 30 and
`the preparation of the rod ends 60 can be done simulta- (cid:9)
`to absorb the negative load forces and to thereby resist failure
`neously. With the same regard, the inspection and assembly 5 of the rod connection. Wedges transmit the compressive and
`steps may be done in the same area or the parts may be moved
`tensile forces of pumping from the steel connector or end
`to specific areas for performing specific steps. It should be
`fitting to the fiberglass rod and vice-versa. The metal end
`further appreciated that a variety of means may be employed
`fitting 30 is harder than the hardened adhesive, and deforms
`to achieve the same result without departing from the spirit of
`the shape of the hardened adhesive wedge. Essentially, the
`the invention described herein. (cid:9)
`10 metal end fitting 30 squeezes the deformations in the adhesive
`For purposes of the present disclosure, the term "wave,"
`when compressive and back travel forces are applied to the
`"wave-shaped," "sine-wave" or "S-shaped" refers to the (cid:9)
`construction. Ideally, the deformations are squeezed by the
`asymptotic character of the curvature of the present transition (cid:9)
`end fitting 30 out toward the end of the rod, transmitting the
`surfaces. Asymptotic curvature may be understood by distin- (cid:9)
`forces, at least to some extent, into the metal end fitting 30 for
`guishing it from tangential or arcuate curvature. A tangential 15 optimum dispersal of destructive forces.
`or arcuate curve retains the potential to intersect with or
`Axial forces applied to a rod cause deformations of the rod
`contact the outer surface of the rod 12 if the curve is suffi- (cid:9)
`material. The deformations are transmitted throughout the
`ciently extrapolated. An asymptotic curve, by contrast, is an (cid:9)
`rod body 12 and vary depending on the magnitude of the force
`infinite regression that will not intersect with the rod 12
`and the cross-sectional area of the rod 12. Abrupt changes in
`regardless of any extrapolation of the curve. Any curvature of 20 the cross-sectional area of the rod 12 concentrate stress forces
`an annular transition surface that is not asymptotic will create
`in certain areas of the rod 12. The wedges of sucker rod 12
`an abrupt discontinuity in the wedge formed thereby, possibly (cid:9)
`connections change the cross-sectional area of the rod 12 in
`resulting in the spiking of destructive forces into the rod body (cid:9)
`comparison to the rod body 12 in such a way as to concentrate
`12. (cid:9)
`stress forces on the rod 12. The concentrated forces may
`FIGS. 4 and 4A illustrate the end fitting 30, which can be 25 exceed the structural strength of the composite material of the
`mounted on any sucker rod whether continuous, or of com- (cid:9)
`rod 12, resulting in rod 12 failure from cracking or splinter-
`mercial length, or any length therebetween. The sucker rod 12
`ing. Early rod 12 designs were plagued with premature fail-
`is preferably inserted into the bottom end fitting chamber 32. (cid:9)
`ure. Failure analysis of these early designs revealed that fail-
`It should be understood that the cross-sectional shape of the (cid:9)
`ure, while exhibiting itself catastrophically, is rarely a result
`end fitting 30 should substantially match the cross-sectional 30 of a catastrophic event. The exhibition of catastrophic failure
`shape of the sucker rod 12. For example, not intended as
`is usually a result of improper maintenance and materials
`limiting, if the sucker rod 12 cross-section is substantially
`handling procedures. Further, the failure, regardless of its
`circular, the cross-sectional shape of the bottom chamber 32
`manifestation, can be linked to the interface between the
`of the end fitting 30 would be substantially circular. For a
`fiberglass rod 12 and the metal end fitting 30. It was still
`further example, not intended as limiting, if the sucker rod 12 35 further found that the end fitting 30 designs that distribute
`cross-section is substantially polygonal, the cross-sectional
`applied stresses more fully along the length of the interface
`shape of the bottom chamber 32 of the end fitting 30 would be (cid:9)
`are more successful in reducing failure.
`substantially polygonal. However, it is foreseeable for the
`Therefore, the preferred sucker rod 12 connectors, such as
`cross sectio