(12) United States Patent
`Rutledge et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 9,181,757 B2
`Nov. 10, 2015
`
`US009181757B2
`
`(54) SUCKER ROD APPARATUS AND METHOD
`(75) Inventors: Russell P. Rutledge, Big Spring, TX
`(US); Russell P. Rutledge, Jr., Big
`Spring, TX (US); Ryan B. Rutledge,
`Big Spring, TX (US)
`(73) Assignee: FINALROD IP, LLC, Big Spring, TX
`(US)
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 861 days.
`(21) Appl. No.: 13/385,410
`(22) Filed:
`Feb. 17, 2012
`(65)
`Prior Publication Data
`|US 2013/0039691 A1
`Feb. 14, 2013
`
`(*) Notice:
`
`Related U.S. Application Data
`(63) Continuation-in-part of application No. 13/136,715,
`filed on Aug. 9, 2011, now Pat. No. 8,851,162.
`(51) Int. Cl.
`E2IB 17/04
`E2IB 43/12
`E2IB I 7/10
`(52) U.S. CI.
`CPC ............. E2IB 1704 (2013.01); E2IB 17/1071
`(2013.01); E2IB 43/127 (2013.01); Y10T
`403/47 (2015.01); Y10T403/473 (2015.01);
`Y101'403/7039 (2015.01)
`
`(2006.01)
`(2006.01)
`(2006.01)
`
`
`
`(58) Field of Classification Search
`None
`See application file for complete search history.
`
`(56)
`
`References Cited
`|U.S. PATENT DOCUMENTS
`4,401,396 A
`8/1983 McKay
`4,475,839 A 10/1984 Strandberg
`4,585,368 A * 4/1986 Pagan ........................... 403/266
`4,653,953 A
`3/1987 Anderson et al.
`:::::... * i lº i. º
`4,919,560 A
`4/1990 Rutledge, Jr. et al.
`5,253,946 A 10/1993 Watkins
`6,193,431 B1
`2/2001 Rutledge
`8,113,277 B2
`2/2012 Rutledge et al.
`2008/0219757 A1
`9/2008 Rutledge et al.
`OTHER PUBLICATIONS
`PCT search report for PCT/US 12/00347 dated Nov. 29, 2012 (26
`pages).
`
`3 - 4–2–3
`
`Wasaki et al.
`
`* cited by examiner
`
`Primary Examiner – Giovanna C Wright
`(57)
`ABSTRACT
`The present disclosure relates to a fiberglass rod with connec
`tors on each end. Each connector has a rod-receiving recep
`tacle having an open end, a closed end, and axially spaced
`annular wedge shaped surfaces such that the compressive
`forces between the rod and the respective connector are
`defined by the shape of the wedged surfaces.
`81 Claims, 6 Drawing Sheets
`
`Page 1 of 17
`
`Petitioners' Exhibit 1024
`John Crane v. Finalrod
`IPR2016-01786
`
`

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`U.S. Patent
`
`Nov. 10, 2015
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`Sheet 1 of 6
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`US 9,181,757 B2
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`
`
`FIG. 1
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`Page 2 of 17
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`

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`U.S. Patent
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`Nov. 10, 2015
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`Sheet 2 of 6
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`US 9,181,757 B2
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`G.2 Fl
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`Page 3 of 17
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`U.S. Patent
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`Nov. 10, 2015
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`Sheet 3 of 6
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`US 9,181,757 B2
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`
`
`f
`
`120B {
`|
`124- )
`
`WEDGE |
`
`WEDGE 2
`
`WEDGE 3
`
`FIG.9
`
`Page 4 of 17
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`U.S. Patent
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`Nov. 10, 2015
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`Sheet 4 of6
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`US 9,181,757 B2
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`G4 A 122
`G3 A 122
`100
`1oo
`112 E 112
`
`FIG.3
`II
`
`FIG.4T__.._:j.
`
`as A 122
`0.5 R 122
`m0
`100
`112 E 112
`
`FIG.5
`
`FIG 6
`22-11:2
`
`as A 122
`G? A 122
`100
`100
`112 E 112
`
`FIG.7
`T
`2:2.
`
`FIG.8
`1
`:21:
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`Page 5 of 17
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`Page 5 of 17
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`U.S. Patent
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`Nov. 10, 2015
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`Sheet 5 of 6
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`US 9,181,757 B2
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`Page 6 of 17
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`U.S. Patent
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`Nov. 10, 2015
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`Sheet 6 of 6
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`US 9,181,757 B2
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`FIG. 11
`
`FIG. 12
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`Page 7 of 17
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`US 9,181,757 B2
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`1
`SUCKER ROD APPARATUS AND METHOD
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`
`The present application is a continuation-in-part applica-
`tion of the application of Russell P. Rutledge, Russell P.
`Rutledge, Jr. and Ryan B. Rutledge, U.S. Ser. No. 13/136,
`715, filed Aug. 9, 2011 now U.S. Pat. No. 8,851,162, entitled
`Sucker Rod Apparatus and Method.
`
`FIELD
`
`The present disclosure relates generally to oil well sucker
`rods. In particular, the disclosure relates to oil well sucker
`rods made of fiberglass with end fittings or connectors on
`each end and the manufacture thereof.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The accompanying drawings, which are incorporated in
`and constitute a part of the specification, illustrate preferred
`embodiments of the disclosure and together with the general
`description of the disclosure and the detailed description of
`the preferred embodiments given below, serve to explain the
`principles of the disclosure.
`FIG. 1 illustrates a typical pumping system for use with the
`technology of the present disclosure.
`FIG. 2 is a cross-sectional View of an embodiment of a
`
`sucker rod and an associated end fitting within the scope of
`the present disclosure.
`FIG. 2A is an exploded View of the blow-up section 2A as
`illustrated in FIG. 2 illustrating the angles between the lead-
`ing edge and the trailing edge of a wedged-shaped portions of
`the wedge system.
`FIG. 3 is a sectional View of the sucker rod and end fitting
`combination illustrated in FIG. 2 taken along the section line
`3-3.
`
`FIG. 4 is a sectional View of the sucker rod and end fitting
`combination illustrated in FIG. 2 taken along the section line
`4-4.
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`FIG. 5 is a sectional View of the sucker rod and end fitting
`combination illustrated in FIG. 2 taken along the section line
`5-5.
`
`45
`
`FIG. 6 is a sectional View of the sucker rod and end fitting
`combination illustrated in FIG. 2 taken along the section line
`6-6.
`
`FIG. 7 is a sectional View of the sucker rod and end fitting
`combination illustrated in FIG. 2 taken along the section line
`7-7.
`
`50
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`2
`
`the wedge portion of the wedge system illustrated in FIG. 11
`within the scope of the present disclosure.
`The depicted embodiments of the sucker rod and associ-
`ated connectors are described below with reference to the
`
`listed Figures.
`The aboVe general description and the following detailed
`description are merely illustratiVe of the generic disclosure,
`and additional modes, adVantages, and particulars of this
`disclosure will be readily suggested to those skilled in the art
`without departing from the spirit and scope of the disclosure.
`
`DETAILED DESCRIPTION OF THE
`EMBODIMENTS
`
`In many oil wells, the pressure in the oil reservoir is not
`sufficient to lift the oil to the surface. In such cases, it is
`conVentional to use a sub-surface pump to force the oil from
`the well. A pumping unit located at the surface driVes the
`sub-surface pump. The pumping unit is connected to the
`sub-surface pump by a string of sucker rods. The pumping
`unit moVes the sucker rod string up and down to driVe the
`sub-surface pump.
`Originally, a sucker rod was a special steel pumping rod. A
`sucker rod is, typically, a steel rod that is used to make up the
`mechanical assembly between the surface and the down hole
`components of a rod pumping system. SeVeral sucker rods
`were screwed together to make up the mechanical link, or
`sucker rod string, from a beam-pumping unit on the surface to
`the subsurface pump at the bottom of a well. The sucker rods
`were threaded on each end and manufactured to dimension
`
`standards and metal specifications set by the petroleum indus-
`try. Typically, sucker rods haVe been in the lengths of 25 or 30
`feet (7.6 or 9.1 meters), and the diameter Varies from 1/2 to 1%;
`inches (12 to 30 millimeters).
`Thus, sucker rod pumping is a method of artificial lift in
`which a subsurface pump located at or near the bottom of the
`well and connected to a string of sucker rods is used to lift the
`well fluid to the surface. The weight ofthe rod string and fluid
`is counterbalanced by weights attached to a reciprocating
`beam or to the crank member of a beam-pumping unit or by
`air pressure in a cylinder attached to the beam.
`Due to the heaVy weight of the steel sucker rods, large
`pumping units were required and pumping depths were lim-
`ited. It is now preferable to use sucker rods made of fiberglass
`with steel connectors. The fiberglass sucker rods proVide
`sufficient strength, and weigh substantially less than steel
`rods.
`
`Since the deVelopment of the fiberglass sucker rod, there
`haVe been continued efforts to improVe the sucker rod, and
`particularly, the relationship between the steel connectors and
`the successiVe rods.
`
`FIG. 8 is a sectional View of the sucker rod and end fitting
`combination illustrated in FIG. 2 taken along the section line
`8-8.
`
`FIG. 9 is a graph of the relationship between the length on
`the ordinate of the leading edge and trailing edge of each
`wedged-shaped portion on the abscissa in the wedge system
`of the present disclosure.
`FIG. 10 is a cross-sectional View ofanother embodiment of
`
`a sucker rod and an associated end fitting within the scope of
`the present disclosure.
`FIG. 11 is a sectional View ofthe sucker rod and end fitting
`combination illustrated in FIG. 10 taken along the apogee of
`one of the wedge portions of the wedge system within the
`scope of the present disclosure.
`FIG. 12 is a sectional View ofthe sucker rod and end fitting
`combination illustrated in FIG. 10 taken along the Vortex of
`
`FIG. 1 illustrates a generic pumping system 20. The pump-
`ing system 20 includes a pump driVe 22, which is a conVen-
`tional beam pump, or pump jack and is connected to a down
`hole pump 26 through a sucker rod string 24 inserted into
`wellbore 28. The sucker rod string 24 can comprise a con-
`tinuous sucker rod 10, which extends from the down hole
`pump 26 to the pumping system 20, a series of connected
`sucker rods 10, a series of conVentional length rods connected
`together, or any combination thereof. The pump driVe 22
`includes a horsehead 22A, a beam 22B, a gearbox 22c and a
`motor 22D. Preferably, the sucker rod 10 is a fiberglass,
`composite or rod haVing similar characteristics. As described
`herein, the sucker rod string 24 may be the same as the
`continuous sucker rod 10 when the continuous sucker rod 10
`
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`is a one-piece rod that extends substantially between the
`pump driVe 22 and the sub-surface pump 26.
`
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`US 9,181,757 B2
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`FIG. 2 is a cross-sectional view of an embodiment of the
`sucker rod 10 comprising a fiber composite rod 200 and
`associated end fitting 100 within the scope of the present
`disclosure. The sucker rod 10 comprises one or more end
`fittings 100 and the fiber composite rod 200. The fiber com
`posite rod 200 has a first end 202 and a second end (not
`illustrated).
`Typically, there are end fittings 100 on each end of the fiber
`composite rod 200 for coupling together a plurality of fiber
`composite rods 200. The end fitting 100 comprises an exterior
`surface 102, a closed end 104, an open end 106, and an
`interior surface 108. The interior surface 108 comprises a
`wedge system 110. The present disclosure provides that the
`wedge system 110 can have any number of wedges from one
`to multiple wedges. The embodiment illustrated in FIG. 2 has
`three wedges. The wedge system 110 defines a cavity 112 in
`the end fitting 100 for receiving the fiber composite rod 200.
`Further, the wedge system 110 comprises a plurality of
`wedged-shaped portions 114. Each wedged-shaped portion
`114 has an apogee 116, a perigee 124, a leading edge 118 and
`a trailing edge 120 extending from and between the apogee
`116 and the perigee 124. Each apogee 116 forms a perimeter
`122 within the cavity 112 that is the narrowest part of the
`cavity 112 associated with each wedge shaped portion 114.
`Each perigee 124 is the widest part of the cavity 112 associ
`ated with each wedge shaped portion 114. The leading edge
`118 is longer than the trailing edge 120 with the leading edge
`118 facing the open end 106 and the trailing edge 120 facing
`the closed end 104 with respect to each wedge shaped portion
`114 of the end fitting 100.
`The first wedge shaped portion 114A is proximate to the
`closed end 104 for receiving compressive forces that are
`greater than the compressive forces associated with the other
`wedged-shaped portions 114B, 114C. Particularly, the first
`wedged-shaped portion 114A receives greater compressive
`forces than the compressive force for which a second wedge
`shaped portion 114B receives that is proximate to the first
`wedged-shaped portion 114A. A third wedge shaped portion
`114C between the second wedge shaped portion 114B and the
`open end 106 receives compressive forces that are less than
`the compressive forces associated with the first and second
`wedge shaped portions 114A, 114C. Therefore, the compres
`sive forces create a force differential along each wedge
`shaped portion 114 greater at the closed end 104 of the end
`fitting 100 and decreasing toward the open end 106 of the end
`fitting 100.
`As the compressive forces associated with the first
`wedged-shaped portion 114A deteriorate the structural integ
`rity of the first wedged-shaped portion 114A, then, it has been
`found that the uncompensated for compressive forces of the
`first wedged-shaped portion 114A are transferred to and
`accepted by the second wedged-shaped portion 114B. Simi
`larly, as the compressive forces associated with the second
`wedged-shaped portion 114B deteriorate the structural integ
`rity of the second wedged-shaped portion 114B, then it has
`55
`been found that the uncompensated for compressive forces of
`the second wedged-shaped portion 114B are transferred to
`and accepted by the third wedged-shaped portion 114C.
`Thus, a force transfer continuum is created by the wedge
`system 110. The force transfer continuum provides for a
`constant effectiveness between the end fitting 100 and the
`fiber composite rod 200 as the wedge system 110 deteriorates
`from one wedged-shaped portion 114 to the next wedged
`shaped portion 114 of the wedge system 110. The present
`structure of the sucker rod 10 including specifically the end
`fitting 100 does not distribute the compressive forces
`throughout the end fitting 100, but rather focuses the com
`
`4
`pressive forces on each wedge shaped portion 114 of the
`wedge system 110 of the present disclosure.
`The sucker rod 10 has a plurality of longitudinal cross
`sections of the wedged-shaped portions 114, which forms a
`plurality of frustro-conical shapes within the cavity 112.
`The wedge shaped portions 114 of the sucker rod 10 create
`different compressive forces on each respective edge 118,
`120 thereof with the compressive force being approximately
`proportional to a length of each edge 118, 120. In one embodi
`ment, the compressive force on each edge 118, 120 is directly
`proportional to the length of each edge 118, 120. Further, the
`plurality of wedge shaped portions 114 are determined by the
`angles associated between the leading edge 118 and the trail
`ing edge 120.
`An adhesive or epoxy 130 is used to sufficiently bond with
`the fiber composite rod 200 and engage with the end fitting
`100. It is appreciated that any adhesive substance that will
`sufficiently bond with the fiber composite rod 200 and engage
`with the end fitting 100 may be used. The adhesive or epoxy
`130 is placed in the cavity 112 and cured to bond with the fiber
`composite rod 200 in the cavity 112 for fixedly securing the
`end fitting 100 with the fiber composite rod 200.
`FIG. 2A is an exploded view of the blow-up section 2A as
`illustrated in FIG. 2 illustrating the angles between the lead
`ing edge and the trailing edge of a wedged-shaped portion of
`the wedge system. In one embodiment, the angle A between
`the leading edge 118 and the trailing edge 120 of each wedge
`shaped portion is obtuse having an angle greater than 90
`degrees. FIG. 2 illustrates an angle A associated with each
`wedged-shaped portion 114 of the wedge system 110.
`FIG. 2A is an exploded view of the blow-up section 2A as
`illustrated in FIG. 2 illustrating the angles between the lead
`ing edge 118B and the trailing edge 120B of a wedged-shaped
`portion 114B of the wedge system 110. The fiber composite
`rod 200 is illustrated in the end fitting 100. The end fitting 100
`defines the leading edge 118B and the trailing edge 120B to
`form the cavity 112 to be filled by the epoxy 130. The angle
`between the leading edge 118B and the trailing edge 120B
`defines the angle A. The angle A is obtuse having an angle
`greater than 90 degrees. Generally, the leading edge 118, the
`trailing edge 120 and the fiber composite rod 200 form a
`scalene triangle with the longest side of the scalene triangle
`being along the fiber composite rod 200, the shortest side of
`the scalene triangle being along the trailing edge 120, and the
`intermediate side of the scalene triangle being along the lead
`ing edge 118.
`FIG. 2A also illustrates the angle B between the trailing
`edge 120B of the wedge shaped portion 114B and the leading
`edge 118A of the wedge shaped portion 114A. Thus, the
`angle B defines the relationship between the trailing edge 120
`of the wedge shaped portion 114 and the leading edge 118 of
`an adjacent wedge shaped portion 114. The angle B is a reflex
`angle. A reflex angle is an angle that exceeds 180 degrees.
`FIG. 3 is a sectional view of the fiber composite rod 200
`and end fitting 100 combination illustrated in FIG. 2 taken
`along the section line 3-3. The end fitting 100 is exterior of the
`fiber composite rod 200 with the cavity 112 there between.
`The cavity 112 between the fiber composite rod 200 and the
`end fitting 100 forms a gap G3. It is appreciated with respect
`to practicing the innovation of the present disclosure that the
`gap can be of any dimension, for example, from as small as
`zero or no gap to as large a gap as required to achieve the
`efficacy of the present disclosure.
`FIG. 4 is a sectional view of the fiber composite rod 200
`and end fitting 100 combination illustrated in FIG. 2 taken
`along the section line 4-4. The end fitting 100 is exterior of the
`fiber composite rod 200 with the cavity 112 there between.
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`5
`The cavity 112 between the fiber composite rod 200 and the
`end fitting 100 forms a gap G4. The gaps G3 and G4 are
`associated with the first wedged-shaped portion 114A of the
`wedge system 110.
`FIG. 5 is a sectional view of the fiber composite rod 200
`and end fitting 100 combination illustrated in FIG. 2 taken
`along the section line 5-5. The end fitting 100 is exterior of the
`fiber composite rod 200 with the cavity 112 there between.
`The cavity 112 between the fiber composite rod 200 and the
`end fitting 100 forms a gap G5.
`FIG. 6 is a sectional view of the fiber composite rod 200
`and end fitting 100 combination illustrated in FIG. 2 taken
`along the section line 6-6. The end fitting 100 is exterior of the
`fiber composite rod 200 with the cavity 112 there between.
`The cavity 112 between the fiber composite rod 200 and the
`end fitting 100 forms a gap G6. The gaps G5 and G6 are
`associated with the second wedged-shaped portion 114B of
`the wedge system 110.
`FIG. 7 is a sectional view of the fiber composite rod 200
`and end fitting 100 combination illustrated in FIG. 2 taken
`along the section line 7-7. The end fitting 100 is exterior of the
`fiber composite rod 200 with the cavity 112 there between.
`The cavity 112 between the fiber composite rod 200 and the
`end fitting 100 forms a gap G7.
`FIG. 8 is a sectional view of the fiber composite rod 200
`and end fitting 100 combination illustrated in FIG. 2 taken
`along the section line 8-8. The end fitting 100 is exterior of the
`fiber composite rod 200 with the cavity 112 there between.
`The cavity 112 between the fiber composite rod 200 and the
`end fitting 100 forms a gap G8. The gaps G7 and G8 are
`associated with the second wedged-shaped portion 114C of
`the wedge system 110.
`FIG. 11 is a sectional view of the sucker rod 10 including
`the end fitting 100 combination illustrated in FIG. 10 taken
`along the apogee 116 of one of the wedge portions 114 of the
`wedge system 110 within the scope of the present disclosure.
`The end fitting 100 is exterior of and engaged with the fiber
`composite rod 200 with no cavity 112 there between. The lack
`of a cavity 112 between the fiber composite rod 200 and the
`end fitting 100 forms a zero gap G9. It is appreciated with
`respect to practicing the innovation of the present disclosure
`that the gap can be of any dimension, for example, from as
`small as zero or no gap, as illustrated in FIG. 11, to as large a
`gap as required to achieve the efficacy of the present disclo
`SUIre.
`FIG. 12 is a sectional view of the sucker rod 10 and includ
`ing the end fitting 100 combination illustrated in FIG. 10
`taken along the vortex 124 of the wedge portion 114 of the
`wedge system 110 illustrated in FIG. 11 within the scope of
`the present disclosure. The end fitting 100 is exterior of the
`fiber composite rod 200 with the cavity 112 there between.
`The cavity 112 between the fiber composite rod 200 and the
`end fitting 100 forms a gap G10. It is appreciated with respect
`to practicing the innovation of the present disclosure that the
`gap can be of any dimension, for example, from as small as
`zero or no gap to as large a gap as required to achieve the
`efficacy of the present disclosure.
`The smaller gaps G3, G5, G7, G9 associated with each
`wedged-shaped portion 114 are substantially constant having
`essentially the same dimension. Similarly, the larger gaps G4,
`G6, G8, G10 associated with each wedged-shaped portion
`114 are substantially constant having essentially the same
`dimension. The symmetry provided by the relationship of the
`minimum gaps G3, G5, G7, G9 and the maximum gaps G4,
`G6, G8, G10 provides unforeseen results. Particularly, the
`symmetry provided by the relationship of the minimum gaps
`G3, G5, G7, G9 and the maximum gaps G4, G6, G8, G10
`
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`6
`greatly enhances the stability and ability of the fiber compos
`ite rod 200 and end fitting 100 combination to accept
`enhanced compressive and back pressure forces associated
`with the reciprocating environment in which the sucker rods
`10 are used.
`FIG. 9 is a graph of the relationship between the length on
`the ordinate (x-axis) of the leading edge 118 and the trailing
`edge 120 of each wedged-shaped portion 114 on the abscissa
`(y-axis) in the wedge system 110 of the present disclosure. As
`illustrated in FIG. 2, the leading edge 118 is progressively
`longer from the closed end 104 of the end fitting 100 to the
`open end 106 of the end fitting 100. Similarly, the trailing
`edge 120 is progressively longer from the closed end 104 of
`the end fitting 100 to the open end 106 of the end fitting 100.
`The functions defined by these relationships are illustrated in
`FIG. 9. Particularly, a line having a slope or gradient defines
`the function associated with the trailing edge 120, and a line
`having a slope or gradient defines the function associated with
`the leading edge 118.
`The relationship of the function associated with the trailing
`edge 120 and the function associated with the leading edge
`118 provides insight to the unforeseen effectiveness of the
`wedge system 110 of the present disclosure. It has been found
`that the rate of increase of the length of the leading edge 118
`with respect to the rate of increase of the length of the trailing
`edge 120, as defined by the slope or gradient of each associ
`ated function, provides an enhanced sucker rod 10 and sucker
`rod system. The slope of the leading edge 118 associated with
`the wedge system 110 of the present disclosure is greater than
`the slope of the trailing edge 120 associated with the wedge
`system 110 of the present disclosure.
`The wedge system 110 of the present disclosure as applied
`to a sucker rod 10 provides unforeseen effectiveness not
`before appreciated. The combination of the wedged-shaped
`portions 114, the relationship of the leading edge 118 to the
`trailing edge 120, the symmetry of the minimum gaps G3, G5,
`G7, G9 and the maximum gaps G4, G6, G8, G10 result in a
`wedge system 110 that provides improved and unpredicted
`functionality. Particularly, the improved and unpredicted
`functionality of the sucker rod 10 having the wedge system
`110 of the present disclosure greatly enhances the stability of
`the sucker rod 10 and ability of the fiber composite rod 200
`and end fitting 100 combination to accept enhanced compres
`sive and back pressure forces associated with the reciprocat
`ing environment in which the sucker rods 10 are used.
`The change of the length of the leading edge increases from
`the inner wedge to the outer wedge. However, the rate of
`change of the length of the leading edge is greater than the rate
`of change of the trailing edge. This is evidenced by the slope
`of the line for the leading edge 1 and the slope of the line for
`the trailing edge 2 illustrated in FIG. 9. For another example,
`if the slope of the line representing the trailing edge was 1,
`then the line would be horizontal in FIG. 9. Then, the slope of
`the line representing the leading edge would be any value
`greater than 1, and would be angled upward from left to right
`in FIG. 9.
`It has not been know before that such an arrangement
`would provide the unexpected results achieved by the present
`disclosure. Particularly, the unexpected results achieved by
`the present end fitting design distributes the stresses to the
`interior wedge first, and thereafter to the next successive
`wedges in the wedge system. The prior art teaches away from
`achieving such results. The prior art describes wedge systems
`that distribute the stresses along the entire length of the wedge
`system.
`Further, the relationship of the rate of change of the lengths
`of the leading edge to the trailing edge illustrated in FIG. 9 is
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`7
`not described in or anticipated by the prior art. The increased
`rate of change of the length of the leading edge relative to the
`trailing edge provides enhanced and unexpected characteris-
`tics with respect to the effectiveness of the end fitting of the
`present disclosure. Particularly, the present end fitting design
`concentrates the compressive forces in the strongest part of
`the end fitting, the interior wedge. Thus, there is an increased
`cohesion between the end fitting and the rod. This results in a
`more secure engagement ofthe rod within the end fitting. Still
`further, this results in reduced strain or deformation as a result
`of the forces caused by stress associated with the use of the
`fiberglass rod.
`FIG. 10 is a cross-sectional view ofanother embodiment of
`
`a sucker rod 10 and associated end fitting 100 within the scope
`of the present disclosure. The sucker rod 10 comprises one or
`more end fittings 100 and a fiber composite rod 200. The fiber
`composite rod 200 has a first end 202 and a second end (not
`illustrated).
`Typically, there are end fittings 100 on each end ofthe fiber
`composite rod 200 for coupling together a plurality of fiber
`composite rods 200. The end fitting 100 comprises an exterior
`surface 102, a closed end 104, an open end 106, and an
`interior surface 108. The interior surface 108 comprises a
`wedge system 110. The present disclosure provides that the
`wedge system 110 can have any number of wedges as indi-
`cated by the broken line between the first wedged-shaped
`portion 114A and the second wedged-shaped portion 114B.
`The wedge system 110 defines a cavity 112 in the end fitting
`100.
`
`The wedge system 110 comprises a plurality of wedged-
`shaped portions 114. Each wedged-shapedportion 114 has an
`apogee 116, a perigee 124, a leading edge 118 and a trailing
`edge 120 extending from the apogee 116 and/or the perigee
`124. Each apogee 116 forms a perimeter 122 within the cavity
`112 that is the narrowest part ofthe cavity 112 associated with
`each wedge shaped portion 114. Each perigee 124 forms the
`widest portion of the cavity 112 associated with each wedge
`shaped portion 114. The leading edge 118 is longer than the
`trailing edge 120 with the leading edge 118 facing the open
`end 106 and the trailing edge 120 facing the closed end 104
`with respect to each wedge shaped portion 114.
`The first wedge shaped portion 114A is proximate to the
`closed end 104 for receiving compressive forces that are
`greater than the compressive forces associated with the other
`wedged-shaped portions 114B, C, etc. Particularly, the first
`wedged-shaped portion 114A receives greater compressive
`forces than the compressive forces for which a second wedge
`shaped portion 114B receives that is proximate to the first
`wedged-shaped portion 114A. A third wedge shaped portion
`114C between the second wedge shaped portions 114B and
`the open end 106 receives compressive forces that are less
`than the compressive forces associated with the first and
`second wedge shaped portions 114A, 114C. Therefore, the
`compressive forces create a force differential along each
`wedge shaped portion 114 greater at the closed end 104 of the
`end fitting 100 and decreasing toward the open end 106 ofthe
`end fitting 100.
`As the compressive forces associated with the first
`wedged- shaped portion 1 14A deteriorate the structural integ-
`rity of the first wedged-shaped portion 114A, then it has been
`found that the uncompensated for compressive forces of the
`first wedged-shaped portion 114A are transferred to and
`accepted by the second wedged-shaped portion 114B. Simi-
`larly, as the compressive forces associated with the second
`wedged-shaped portion 114B deteriorate the structural integ-
`rity of the second wedged-shaped portion 114B, then it has
`been found that the uncompensated for compressive forces of
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`the second wedged-shaped portion 114B are transferred to
`and accepted by the third wedged-shaped portion 114C.
`Thus, a force transfer continuum is created by the wedge
`system 110 regardless of the number of wedged-shaped por-
`tions 114 comprise the wedge system 110. The force transfer
`continuum provides for a constant effectiveness between the
`end fitting 100 and the fiber composite rod 200 as the wedge
`system 110 deteriorates from one wedged-shapedportion 114
`to the next wedged-shaped portion 114 of the wedge system
`110.
`
`The wedge shaped portions 114 of the sucker rod 50 create
`different compressive forces on each respective edge 118,
`120 thereof with the compressive force being approximately
`proportional to a length ofeach edge 118, 120. In one embodi-
`ment, the compressive force on each edge 118, 120 is directly
`proportional to the length of each edge 118, 120. Further, the
`plurality of wedge shaped portions 114 are determined by the
`angles associated between the leading edge 118 and the trail-
`ing edge 120.
`An adhesive or epoxy 130 is used to sufficiently bond with
`the fiber composite rod 200 and for engagement with the end
`fitting 100. It is appreciated that any adhesive substance that
`will sufficiently bond with the fiber composite rod 200 and
`engage with the end fitting 100 may be used. The adhesive or
`epoxy 130 is placed in the cavity 112 and cured to bond with
`the fiber composite rod 200 in the cavity 112 for fixedly
`securing the end fitting 100 with the fiber composite rod 200.
`In another embodiment, the angle A between the leading
`edge 118 and the trailing edge 120 of each wedge shaped
`portion is obtuse. FIG. 2A illustrates an angle A associated
`with each wedged-shaped portion 114 of the wedge system
`110 with respect to the present disclosure. FIG. 2A also
`illustrates the angle B between the trailing edge 120B of the
`wedge shaped portion 114B and the leading edge 118A ofthe
`wedge shaped portion 114A. Thus, the angle B defines the
`relationship between the trailing edge 120 of the wedge
`shaped portion 114 and the leading edge 118 of an adjacent
`wedge shaped portion 114. The angle B is a reflex angle. A
`reflex angle is an angle that exceeds 180 degrees.
`The longitudinal cross sections of the concaved portions
`110 form frustro-comcal shapes. The concaved portions 110
`create different compressive forces on each respective surface
`thereof with the compressive force being approximately pro-
`portional to the length of each surface. The compressive force
`on each surface increases toward the closed end 104 and
`
`decreases toward the open end 106. The compressive force on
`each first surface 118 is proportional to the length of each
`surface. The compressive force on each second surface 120 is
`proportional to the length of each second surface.
`The plurality of concaved portions 110 are determined by
`the angle associated between the first surface 118 and the
`second surface 120 of each concaved surface 110. The angle
`between the first surface 118 and the second surface 120 of
`
`each concaved surface 110 is obtuse. Further, each wedge
`shape portion 114 may have a length proportional to the
`compressive force applied to the wedge shape 114. The
`wedge shape 114 has a length that increases from the closed
`end 104 to the open end 106 ofthe end fitting 100. The wedge
`shaped portions 114 may have a length that decreases from
`the closed end 104 to the open end 106 of the end fitting 100.
`In yet another embodiment, a method for manufacturing a
`sucker rod is provided. The method comprises the steps of
`constructing an end fitting comprising an ex