`
`(12) United States Patent (cid:9)
`Rutledge, Sr. et al. (cid:9)
`
`(10) Patent No.: (cid:9)
`(45) Date of Patent: (cid:9)
`
`US 8,113,277 B2
`Feb. 14, 2012
`
`(54)
`
`SUCKER ROD END FITTINGS AND METHOD
`OF USING SAME
`
`(75)
`
`Inventors: Russell P. Rutledge, Sr., Big Spring, TX
`(US); Russell P. Rutledge, Jr., Big
`Spring, TX (US); Ryan B. Rutledge,
`Big Spring, TX (US)
`
`(73)
`
`Assignee: Fiberod, Inc., Moreon Grove, IL (US)
`
`Notice: (cid:9)
`* )
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 352 days.
`
`4,401,396 A * 8/1983 McKay (cid:9)
`4,430,018 A * 2/1984 Fischer (cid:9)
`4,662,774 A * 5/1987 Morrow, Jr. (cid:9)
`RE32,865 E * 2/1989 Rutledge et al. (cid:9)
`4,822,201 A * 4/1989 Iwasaki et al. (cid:9)
`4,919,560 A * 4/1990 Rutledge et al. (cid:9)
`5,253,946 A * 10/1993 Watkins (cid:9)
`6,193,431 B1 * 2/2001 Rutledge (cid:9)
`6,886,484 B2 * 5/2005 Thomas (cid:9)
`2008/0217023 Al * 9/2008 Rutledge (cid:9)
`2008/0217914 Al * 9/2008 Rutledge et al. (cid:9)
`
`OTHER PUBLICATIONS
`
` 403/13
` 403/268
` 403/266
` 403/268
` 403/268
` 403/268
` 403/268
` 403/268
` 114/108
` 166/369
` 285/319
`
`(21)
`
`Appl. No.: 11/715,088
`
`(22)
`
`Filed: (cid:9)
`
`Mar. 5, 2007
`
`(65)
`
`(51)
`
`(52)
`(58)
`
`(56)
`
`Prior Publication Data
`
`US 2008/0219757 Al (cid:9)
`
`Sep. 11, 2008
`
`(2006.01)
`
`Int. Cl.
`E21B 17/02 (cid:9)
` 166/242.6; 166/68
`U.S. Cl. (cid:9)
` 166/105,
`Field of Classification Search (cid:9)
`166/242.6, 378, 380; 403/265, 268, 361
`See application file for complete search history.
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`3,168,340 A * 2/1965 Howard (cid:9)
`4,315,699 A * 2/1982 Lusk (cid:9)
`4,360,288 A * 11/1982 Rutledge et al
`
` 403/182
` 403/361
` 403/268
`
`Merriam-Webster Dictionary's definition of "Routine", accessed
`Dec. 21, 2010 at merriam-websterscom.*
`
`* cited by examiner
`
`Primary Examiner — Jennifer H Gay
`Assistant Examiner — Blake Michener
`(74) Attorney, Agent, or Firm — Leydig, Voit & Mayer Ltd.
`
`(57) (cid:9)
`
`ABSTRACT
`
`An end fitting for sucker rods or continuous sucker rods
`defines a rod receptacle with an interior surface defining void
`spaces having an axial radius of curvature of at least twenty
`inches. In one form, the fitting receptacle defines two such
`void spaces and the radius of curvature differs between them.
`
`7 Claims, 4 Drawing Sheets
`
`30
`
`72
`
`70
`
`74
`
`70
`
`Petitioners' Exhibit 1006
`John Crane v. Finalrod
`IPR2016-01786
`Page 1 of 14
`
`(cid:9)
`
`
`U.S. Patent (cid:9)
`
`Feb. 14, 2012 (cid:9)
`
`Sheet 1 of 4
`
`US 8,113,277 B2
`
`FIG. 1
`
`n, -*.• N.- (cid:9)
`
`I
`
`11
`
`v v. NY NY "V V'
`
`/
`
`FIG. 1A
`
`Page 2 of 14
`
`(cid:9)
`
`
`127
`
`115
`1
`117
`1
`119
`1
`121
`1
`125
`
`130
`1
`132
`1
`134
`1
`138
`1
`140
`1
`142
`1
`144
`1
`
`FIG. 3
`
`Page 3 of 14
`
`
`
`U.S. Patent (cid:9)
`
`Feb. 14, 2012 (cid:9)
`
`Sheet 3 of 4 (cid:9)
`
`US 8,113,277 B2
`
`C
`
`20
`
`c- 30
`
`c-30
`
`72
`
`70
`
`74
`
`70
`
`FIG. 4A
`
`53
`
`---------
`1
`
`
`C
`
`FIG. 4
`
`Page 4 of 14
`
`(cid:9)
`
`
`lualud °Sil
`
`ztoz 171 'VI
`
`17 JO 17 JamiS
`
`za LLecit's sa
`
`FIG. 7
`
`14
`
`FIG. 6
`
`24
`
`50 (cid:9)
`
`(-45 r46 648 (cid:9)
`
`42- 44 -- (cid:9)
`
`40 -
`
`FIG. 5A
`
`FIG. 5
`
`112
`
`16
`
`10
`
`Page 5 of 14
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`
`
`US 8,113,277 B2
`
`1
`SUCKER ROD END FITTINGS AND METHOD
`OF USING SAME
`
`RELATED APPLICATION
`
`5
`
`This application is related to U.S. patent application titled
`Improved Method of Assembling Sucker Rods and End Fit-
`tings, Ser. No. 11/715,087 having a filing date of Mar. 5, 2007
`and is related to U.S. patent application titled Continuous
`Sucker Rod and Method of Using Same, Ser. No. 11/715,085 10
`having a filing date of March 5, 2007.
`
`TECHNICAL FIELD
`
`The present invention relates to oil field production, and 15
`more particularly, to the end fittings used with fiberglass or
`composite sucker rods in conjunction with downhole pumps
`and surface located pump actuation systems.
`
`BRIEF DESCRIPTION OF DRAWINGS (cid:9)
`
`20
`
`2
`conventional pump well known in the art. It should be appre-
`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
`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-
`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 FIGS. 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
`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
`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
`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
`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
`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
`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-
`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
`fitting 30. It should be appreciated that the cleaning step 1 10
`may also include the detection and removal of burrs, metal
`shavings, or other abnormalities left from manufacturing. It
`should be further appreciated that the cleaning step 110 can be
`manually or automatically performed.
`
`30
`
`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 25
`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 35
`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- 40
`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 55
`to the present invention.
`
`45
`
`50
`
`DETAILED DESCRIPTION OF EMBODIMENTS
`OF THE INVENTION
`
`60
`
`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
`14 (FIG. 1). It should be appreciated that pump drive 10 is 65
`typically a pump jack (i.e. a beam pump system) or other
`known pump drive. Further, downhole pump 14 is typically a
`
`Page 6 of 14
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`US 8,113,277 B2
`
`o (cid:9)
`
`4
`3
`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
`able, care should be taken not to deeply scratch of gouge the
`surface and the light scribe marks maybe difficult to see
`that the mold release agent can be a variety of conventional
`mold release agents. The mold release agent will prevent the 5 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, (cid:9)
`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
`60 are sand blasted and in yet another embodiment the sand-
`Preferably, to apply the mold release agent, the cleaned end
`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 15 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 (cid:9)
`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 2o 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 (cid:9)
`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, 25 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/or the standing time may change (cid:9)
`more thorough bonding between the adhesive and the rod
`body 12. It should be apparent, from the description above,
`or be eliminated. It should be understood, that after the mold
`release agent has been poured out, the end fitting 30 should be 30 and as further detailed below, that the adhesive must bond
`allowed to stand so as to allow substantially all the remaining (cid:9)
`with the rod end 60 but should not bond with the end fitting
`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
`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. 35 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 (cid:9)
`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
`should be understood that the exact temperature may vary due 40 12 are preferably ready for the step of assembling the rod
`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 (cid:9)
`prepared end fittings 30 with a predetermined 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 45 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 (cid:9)
`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 so (cid:9)
`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 (cid:9)
`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 55 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- (cid:9)
`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 60 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 (cid:9)
`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 65 but are not limited to, the use of a conventional drill, such as
`placement. The marks 62, 64 can be made in a variety of
`a pneumatic, hydraulic, or air drill, for high speed rotation,
`conventional manners but it is preferable that the mark 62, 64
`using a machine to rotate either or both the rod body 12 and
`
`Page 7 of 14
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`US 8,113,277 B2
`
`5
`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 airpockets, 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
`appreciated that regardless of the means of tracking the curing
`cycle, the rods 12 can be heated in batches or individually.
`
`15 (cid:9)
`
`6
`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 from air
`5 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
`end fittings 30 can be quickly checked, through a visual
`inspection, for any indication that the end fitting 30 has
`10 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
`understood that the pull test is to create and then to check the
`integrity of the mechanical bond between the rod body 12 and
`20 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
`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
`25 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
`24, 26 between the end of the rod 60 and the end fitting 30.
`Preferably, the pull test is conducted at a pre-determined
`30 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
`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
`35 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
`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
`40 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
`30 are visually inspected for a proper assembly. Preferably, if
`the end fittings 30 have been correctly bonded, the end fitting
`45 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
`and cured, forms a "mark" 64' at the original position of the
`end fitting 30. Preferably mark 64' and mark 64 are the same
`so 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
`55 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
`fitting 30 actually moved.
`Next, at step 155, the assembled sucker rod 12 can be
`60 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
`fittings 30, coating the end fittings 30 with a rust inhibitor,
`additional quality control checks or inspections, painting,
`65 crating, or inventorying the finished product.
`It should be appreciated that the above described steps do
`not need to be performed in the exact sequence described.
`
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`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 (cid:9)
`of the rod connection. Wedges transmit the compressive and
`tensile forces of pumping from the steel connector or end
`steps may be done in the same area or the parts may be moved
`to specific areas for performing specific steps. It should be 5 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)
`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 10 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
`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- is 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
`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 20 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 (cid:9)
`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 25 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
`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 30 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
`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 35 are more successful in reducing failure.
`substantially polygonal. However, it is foreseeable for the
`Therefore, the preferred sucker rod 12 connectors, such as
`cross sectional shape of the chamber 32 and the cross-sec- (cid:9)
`illustrated in FIG. 4, achieve a smooth and continuous dis-
`tional shape of the rod to be different. In most cases of such
`persal of forces along the rod-connector interface to avoid the
`across-sectional mismatch, the cross-sectional shape of the (cid:9)
`concentration of forces thereon in excess of the rod 12
`bottom chamber 32 will most likely be circular. It should be 40 strength, while at the same time providing a cooperative
`further understood that the end fittings 30 may be attached, to (cid:9)
`engagement of the connector and the rod 12 to prevent pull-
`a sucker rod 12, while the rod 12 is stored on the reel (if it is (cid:9)
`outs. After a rod 12 is inserted into the receptacle 32 (see FIG.
`a continuous sucker rod) or may be attached at a field location. (cid:9)
`2, step 138), the adhesive fills the void space in the wedges or
`The preferred end fittings 30, as described hereinbelow, (cid:9)
`annuluses of the interior surface of the receptacle 32. The
`enable the use of the presently described sucker rod 12 as the 45 initially flowable adhesive cures or hardens becoming a solid
`preferred end fittings 30 prevent separation from the sucker (cid:9)
`and adhering to the rod 12. The adhesive bonds to the rod 12
`rod 12 as well as prevent the