(12) United States Patent (cid:9)
`Thomas (cid:9)
`
`11111111111111101111111111111I1j111181!111111111111111111110111111
`
`(to) Patent No.: (cid:9)
`(45) Date of Patent: (cid:9)
`
`US 6,886,484 B2
`May 3, 2005
`
`(54)
`
`COMPOSITE TENSION ROD TERMINAL
`SYSTEMS
`
`(76)
`
`Inventor: Georg K. Thomas, 461 Mill Springs
`La., Plantation, FL (US) 33325
`
`( * )
`
`Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 10/366,043
`
`(22) Filed: (cid:9)
`
`Feb. 12, 2003
`
`(65) (cid:9)
`
`Prior Publication Data
`
`US 2004/0156672 Al Aug. 12, 2004
`
` B6311 9/04
`(51) Int. Cl.' (cid:9)
` 114/108; 403/268; 403/334
`(52) U.S. Cl. (cid:9)
` 114/108, 105,
`(58) Field of Search (cid:9)
`114/112; 403/268, 269, 333, 334, 361,
`41; 365/174, 189.01, 185.01, 185.23, 226,
`230.06
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`11/1908 Moench (cid:9)
`902,673 A
`3/1932 Bridges (cid:9)
`1,849,067 A
`3/1932 Bridges (cid:9)
`1,849,069 A
`3/1934 Mulroyan (cid:9)
`1,950,947 A
`6/1936 Davison (cid:9)
`2,045,520 A
`5/1937 Lapointe (cid:9)
`2,079,692 A
`3,507,949 A * 4/1970 Campbell (cid:9)
`3,573,346 A
`4/1971 Appleby (cid:9)
`3,802,373 A * 4/1974 Lagerquist (cid:9)
`3,851,609 A * 12/1974 Stearn (cid:9)
`3,958,523 A * 5/1976 Holmes et al. (cid:9)
`4,023,886 A
`5/1977 Nakayama et al. (cid:9)
`4,127,741 A
`11/1978 Bauer et al. (cid:9)
`4,130,926 A * 12/1978 Willem (cid:9)
`4,653,953 A * 3/1987 Anderson et al. (cid:9)
`4,679,960 A
`7/1987 Mizuhara (cid:9)
`4,822,201 A * 4/1989 Iwasaki et al. (cid:9)
`
` 403/184
` 403/334
` 403/334
` 285/148.22
` 403/41
` 403/334
` 403/268
` 174/71 R
` 114/105
` 114/105
` 114/105
` 385/80
` 174/189
` 403/268
` 403/268
` 403/272
` 403/268
`
`4,917,530 A
`5,297,077 A (cid:9)
`5,415,490 A (cid:9)
`5,463,970 A (cid:9)
`5,611,636 A (cid:9)
`5,629,888 A (cid:9)
`5,713,169 A
`6,301,145 B1 *
`2003/0010966 Al
`
`4/1990 Engelhardt et al. (cid:9)
`* 3/1994 Imai et al. (cid:9)
`* 5/1995 Flory
`* 11/1995 Hartlmeier et al. (cid:9)
`*
`3/1997
`Flory
`*
`5/1997
`Saito et al. (cid:9)
`2/1998
`Meier et al. (cid:9)
`10/2001
`Nishihara
`1/2003 Sjostedt (cid:9)
`
`
`
`
`
`
`
`
`
`
`
`403/334
`365/145
`403/268
`114/105
`403/269
`365/145
`52/223.13
`365/145
`254/231
`
`* cited by examiner
`
`Primary Examiner—Lars A. Olson
`(74) Attorney, Agent, or Firm—Pearne & Gordon LLP
`
`(57) (cid:9)
`
`ABSTRACT
`
`A composite tension rod is received in the sleeve portion of
`a shank that forms part of a terminal fitting, and is spaced
`from the shank sleeve and connected thereto by a potting
`resin. The shank sleeve wall tapers out from thin at its distal
`end to thick at the bury depth of the rod. The rod is tapered
`outwardly from a point of minimum diameter at its inner end
`to its full diameter a given distance from the end. The shank
`sleeve and rod have complementary dual tapering along said
`length such that as the diameter of the rod along said
`distance increases, the wall thickness of the shank sleeve
`decreases. The resin layer and the rod are secured to each
`other against relative longitudinal movement, as are the
`resin layer and the shank sleeve.
`
`In another aspect of the invention, a tension rod sleeve is
`fixed to the tension rod and extends over the distal end of the
`shank sleeve and along all or a majority of the length of the
`shank sleeve. The rod sleeve is tapered so that its wall
`thickness decreases to a minimum in the vicinity of the
`proximal end of the shank sleeve, or the rod sleeve, as it
`extends along the shank sleeve, is divided, or divides, into
`two halves or bands which join to form loop extending
`around a loop-engaging, convex, fiber-turnaround face
`formed on the terminal fitting. Such face extends trans-
`versely from one side to the other of the fitting.
`
`32 Claims, 5 Drawing Sheets
`
`11c (cid:9)
`
`18c,
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`19c
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`Page0000001
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`Pet'rs Exhibit 1017
`John Crane v. Finalrod
`IPR2016-00521
`
`(cid:9)
`(cid:9)
`(cid:9)
`(cid:9)
`(cid:9)
`(cid:9)
`(cid:9)
`(cid:9)
`(cid:9)
`(cid:9)
`(cid:9)
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`(cid:9)
`

`
`U.S. Patent (cid:9)
`
`May 3, 2005
`
`Sheet 1 of 5 (cid:9)
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`US 6,886,484 B2
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`14i (cid:9)
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`A
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`16i
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`12i
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`11i (cid:9)
`
`101
`
`FIG. 1
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`14a
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`19i
`11a 18a
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`10a
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`16a
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`12a\ (cid:9)
`
`,
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`14b
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`FIG. 2A (cid:9)
`12b
`16b
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`/ /
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`1 lb
`
`) (cid:9)
`/// ///
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`2°'
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`19a
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`18b-,
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`10b
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`19b
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`19c
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`„ (cid:9)
`/2? (cid:9)
`, (cid:9)
`FIG. 2B
`
`/ //, /
`
`FIG. 2C
`16c
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`26c
`
`FIG. 2C-1
`
`Page0000002
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`(cid:9)
`(cid:9)
`(cid:9)
`(cid:9)
`(cid:9)
`(cid:9)
`(cid:9)
`

`
`S Jo Z 13311S
`
`Zff 17817'988'9 Sa
`
`f I Of
`
`Ui
`O O
`
`10e
`
`Waled *S'Il
`
`19d
`
`(cid:9)3
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`710d
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`1 8d
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`FIG. 2F-1
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`1 If
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`12f (cid:9)
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`15f
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`19e
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`
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`FIG. 2E
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`FIG. 2D
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`22d
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`"24d
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`12d
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`1-16d
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`/
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`ti/ 7/7j////,
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`14d
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`Page0000003
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`

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`Waled *S11
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`S Jo £ 13311S
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`Zff 17817'988'9 Sa
`
`B
`
`FIG. 2G-2
`
`15g
`
`FIG. 2G-1
`
`('15g
`
`14g 12g
`
`FIG. 2F-2
`
`II (cid:9)V
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`A
`C
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`Page0000004
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`

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`U.S. Patent (cid:9)
`
`May 3, 2005
`
`Sheet 4 of 5 (cid:9)
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`US 6,886,484 B2
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`Page0000005
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`(cid:9)
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`
`U.S. Patent (cid:9)
`
`May 3, 2005
`
`Sheet 5 of 5 (cid:9)
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`US 6,886,484 B2
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`12j
`
`E
`
`/10j
`
`29j
`
`19j E--/--
`FIG. 2J
`
`10k
`
`1 Om
`
`16j
`
`16k
`
`FIG. 2K-1 FIG. 2M-1
`
`—26k
`
`26m
`FIG. 2K-2 FIG. 2M-2
`
`FIG. 2J -I
`
`FIG. 2K-3
`
`Page0000006
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`

`
`1
`COMPOSITE TENSION ROD TERMINAL
`SYSTEMS
`
`US 6,886,484 B2
`
`FIELD OF THE INVENTION (cid:9)
`
`This invention relates to terminal systems for composite
`fiber-reinforced resin tension rods, or cables made up of
`multiple rods, generally formed by pultrusion, hereinafter
`collectively referred to as fiber-reinforced composite rods,
`fiber-reinforced rods, composite tension rods, or as compos-
`ite rods, or tension rods, or simply rods, and comprising
`carbon-fiber-reinforced resins, or resins reinforced with
`other fibers, and having the properties of geometric slimness
`and high tensile strength per unit weight. "Other fibers"
`includes fibers such as Kevlar®, Spectra®, Zylon®, and
`Twaron® brands of fiber, and, in general, fibers or blends of
`fibers that provide high tensile strength per unit weight when
`combined with a polymer resin matrix.
`Composite tension rods differ from ropes or lines made of
`strands of twisted fibers consisting of fiber materials that are
`the same or similar to the fiber materials just mentioned.
`Unlike ropes or lines made of strands of twisted fibers,
`composite tension rods are essentially creep-free, have good
`resistance to abrasion, and are dimensionally stable under
`handling or coiling.
`A terminal system of a kind intended by the invention may
`be embodied at one or both ends of a tension rod, and if at
`both ends, in the same or in different specific forms. Ter-
`minal systems of the invention each include the rod itself at
`one of its ends, a terminal fitting that transfers tensile
`stresses carried by the rod, and a layer of potting resin
`between the rod and the fitting. "Terminal fitting" alludes to
`a terminal for a rod, not necessarily to termination on a deck,
`mast, cross-arm, rail, post, or other fixed element. The term
`therefore includes rod fittings designed to join rods to
`non-fixed elements such as other fittings at the ends of other
`rods, as well as including rod fittings designed to join rods
`to fixed elements such as masts, cross-arms, rails, posts,
`decks or the like. (cid:9)
`
`5
`
`10
`
`15
`
`20
`
`25
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`30
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`35
`
`40
`
`BACKGROUND OF THE INVENTION
`
`The terminal systems of the present invention are par-
`ticularly appropriate in applications where not only is it
`important to minimize the weight of tension rods, but also it 45
`is important to minimize the weight and size of terminal
`fittings and related hardware by providing relatively light
`and geometrically slim terminal systems. An important
`application is sailing yachts, where rigging connects not
`only at the deck but aloft at many locations along the mast, 50
`either at the mast wall or at spreader tips (from which the
`rigging continues up at an angle and at smaller size), and
`where in general each rigging line or stay requires fittings at
`both ends, and many fittings are aloft. If heavy and bulky
`fittings are required for each end of each stay, cable or rod, 55
`the potential advantages of the composite tension rods are
`largely defeated. These constraints have discouraged wide-
`spread employment of composite tension rods in sailing
`yachts despite the potential for improvement in gross weight
`and in weight distribution, and the further advantages of 60
`freeness from creep, good resistance to abrasion, and dimen-
`sional stability under handling or coiling. Composite tension
`rods reinforced with carbon fibers or other of the fiber
`materials mentioned above are believed to have been pul-
`truded as rods of circular cross-section and tried in perfor- 65
`mance applications as diagonals and verticals in yacht
`rigging, but so far as known, to date no commercially
`
`2
`successful design of terminal system has been provided for
`such rods, and their use has languished.
`Applications such as sailing yachts are to be contrasted
`with systems such as bridge roadway construction where
`tensioned bridge stays are continuous across the tops of the
`bridge tower, and require no anchoring fittings aloft, and are
`connected by anchoring members located at ground points at
`or near the roadway, where weight and bulkiness is of little
`or no concern. A known anchoring system for composite
`carbon-fiber reinforced bridge stays used in such an appli-
`cation is disclosed in U.S. Pat. No. 5,713,169. It includes an
`"anchor body" or frustum of potting resin that coaxially
`receives and is bonded to the bridge stay or composite
`tension member. The wall thickness of the cone of potting
`resin varies along the cone length, and is always greater than
`the composite tension member's radius. The cone wall
`thickness increases along the cone length in such a way as
`to preserve the strictly conical shape of the cone of resin, and
`reaches several times the tension member's radius at the
`back end of the cone of resin, that is, the end opposite to the
`point where the free length of the tension member enters the
`front end of the cone. The conical anchor body is slidably
`received in a steel casting or "anchor casing." A "slide film,"
`in the form of a Teflon foil, or a deposit of a "separation
`agent", is included for this purpose. The internal surface of
`the anchor casing must also be strictly conical in shape for
`this purpose, and the interface between the anchor body and
`the anchor casing must be free of any adhesive bond or
`mechanical keying such as threaded engagement at the
`interface. The ability of the anchor body to slide relative to
`the anchor casing is necessary to allow for the proper
`wedging action of the cone and captured compression.
`Systems have been proposed for terminating fiber-
`reinforced tension members used in sailing yachts, but such
`systems relate primarily to tension members consisting of a
`wrapped plurality of rods, rather than to monolithic rod
`pultrudates as in the present invention, and furthermore are
`subject to constraints similar to those of the bridge stay
`terminating systems just discussed. U.S. Patent Application
`Pub. No. 20030010966 shows one such system that, like the
`system of U.S. Pat. No. 5,713,169 cited above, relies on
`slippage (paragraph 0067) and on captured compression
`within a frustum (paragraphs 0053, 0068). The fittings of
`such systems must be designed to withstand high hoop loads
`in the fitting (paragraph 0074). Moreover, to a large extent
`such systems rely on the bundling together of multiple small
`relatively flexible composite rods. When such rods enter a
`bulky fitting, the transition from relatively flexible small
`composite rods to relatively stiff fitting happens in an abrupt
`manner. This means when the rigging is slack (low tension)
`the fitting and rods will bend relative to one another, and
`wear and fatigue at the entrance to the terminal fitting will
`result in premature failure. (This also happens in conven-
`tional wire rigging between the cable and a swaged fitting.
`At a typical sailboat deck the rigging turnbuckle is located
`between the deck chain plate and the swage, and when the
`rigging is not under load the turnbuckle is free to rock back
`and forth in motion with the boat. This motion and the
`weight of the turnbuckle apply a bending load to the cables
`that exit the swage fitting and slightly bend them back and
`forth. Small bundled rods as in the patent application pub-
`lication would not only bend but would also wear against
`each other at this exit location.)
`
`BRIEF DESCRIPTION OF THE INVENTION
`The present invention overcomes the above-discussed
`constraints and disadvantages of prior-art terminal systems
`
`Page0000007
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`US 6,886,484 B2
`
`3
`for composite tension members. The invention accomplishes
`termination or anchoring of a composite tension rod by a
`terminal system that is geometrically slim, relatively light,
`free of thick layering of potting resin, and free of the need
`to provide parts adapted to slide with respect to each other 5
`or to generate captured compression. The invention provides
`a system in which the potting resin is relatively thinly
`layered around the tension rod and is fixed to both the
`tension rod and to a surrounding shank sleeve that coaxially
`surrounds the tension rod and the layer of potting resin. The 10
`shank sleeve is formed by a bore extending from the end of
`the shank of a fitting and is filled with the resin and the
`tension rod. Tapering of the parts so as to vary their
`cross-sections along the bury length of the tension rod (the
`length that the rod extends into the bore beyond the entry 15
`point) operates to reduce elevation of load-transfer intensity
`values (in units of force per unit area, such as pounds per
`square inch) at regions near the ends of the bore locations
`above those of adjacent regions within the bore as compared
`to what such elevation would be in the absence of tapering, 20
`thereby contributing to uniformity of load transfer along the
`bore.
`The invention also contemplates fittings that include a rod
`sleeve attached to the rod proper and extending along the
`exterior of the shank sleeve. The rod sleeve may be tapered
`to reduce elevation of load-transfer intensity values between
`it and the exterior of the shank sleeve, or may be formed to
`include tension-carrying bands.
`These and related features, more fully described below,
`result in light and geometrically slim terminal arrangements
`which may be used at the ends of tension rods employed in
`the rigging of a yacht to provide a superior combination of
`strength and lightness in both tension rods and fittings at
`many or all points, high and low, throughout the rigging.
`The invention is not restricted to use in sailing yachts or
`other sailing vessels, and may also be employed in other
`applications such as for example pultruded composite ten-
`sion rods used along with circular isolator disks to electri-
`cally isolate power transmission lines from towers or other
`structures that carry them, or in still other applications
`where, although avoidance of bulkiness of the terminal
`fitting is of little or no importance, other attributes of the
`invention remain attractive. Such still other applications
`may include for example mooring lines for ships or floating
`platforms, or stays for land based structures.
`
`25
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`30
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`35
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`40
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`45
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a partly broken-away view of components of an
`imaginary or hypothetical terminal system that is useful as
`an aid in describing the present terminal system invention,
`but that does not embody the present terminal system
`invention. FIG. 1 includes a fitting and one end of a
`composite tension rod. The terminal system whose compo-
`nents are shown in FIG. 1 is neither known to be nor
`believed to be prior art.
`FIG. 2A is a partly broken-away view of components of
`a terminal system that does embody the present terminal
`system invention. FIG. 2A includes a fitting and one end of
`a composite tension rod.
`FIGS. 2B and 2C are partly broken-away views of com-
`ponents of other terminal systems that embody the present
`terminal system invention.
`FIG. 2C-1 is a fragmentary view showing an alternative
`to the structure shown in FIG. 2C.
`FIG. 2D is a cross-sectional view of still another terminal
`system that embodies the present terminal system invention.
`
`50
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`55
`
`60
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`65
`
`4
`As compared to the other drawings, FIG. 2D more accu-
`rately scales length and width dimensions to each other in
`order to better convey an idea of the degree of geometric
`slimness that the present invention can provide.
`FIG. 2E is a partly broken away view of another terminal
`system that embodies the invention. This figure is not as
`accurately scaled as FIG. 2D, but is of the general style as
`most of the other drawings.
`FIG. 2F-1 is a view taken on line B—B in FIG. 2F-2.
`FIG. 2F-2 is a plan view of another terminal system
`embodying the invention.
`FIG. 2G-1 is a view taken on line C—C in FIG. 2G-2
`FIG. 2G-2 is a plan view of another terminal system
`embodying the invention.
`FIG. 2H-1 is a view taken on line D—D in FIG. 2H-2.
`FIG. 2H-2 is a plan view of another terminal system
`embodying the invention.
`FIG. 2J is a view, partly in cross-section, of still another
`embodiment of the invention, drawn on a somewhat larger
`scale than are most of the drawings.
`FIG. 2J-1 is a view taken on line E—E in FIG. 2J.
`FIG. 2K-1 is a cross-section of another shape of rod that
`may be used in the practice of the invention, made up of two
`smaller rods.
`FIGS. 2K-2 and 2K-3 are cross-sections illustrating steps
`in the building-up of an end portion of the rod seen in FIG.
`2K-1.
`FIG. 2M-1 is a cross-section of another rod that may be
`used in the practice of the invention.
`FIG. 2M-2 is a cross-section illustration the building-up
`of an end portion of the rod seen in FIG. 2M-1.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`In order to best describe the terminal systems of the
`invention, it is convenient to first describe an imaginary or
`hypothetical terminal system. Imagine a terminal system at
`one end of a composite tension rod as seen in FIG. 1. The
`tension rod, labeled 10i in the drawing, is of conventional
`round (circular) cross-section, and is received in the bore lli
`of a sleeve 12i. The sleeve is formed as part of the shank 14i
`of a terminal fitting, in this case an eye. The eye may have
`a threaded bore (not shown) in which exterior threading (not
`shown) on the shank is received, the eye being turned down
`tightly on the shank to form a fitting, in this case the eye. The
`shank could join to parts other than an eye to form other
`common types of fittings, such as forks, stud terminals, or
`swivel bails, or join to tees, cross-pins or barrels that form
`part of toggle connections, or the shank could be somewhat
`elongated and threaded for a required adjusting distance to
`function as part of a turnbuckle connection.
`Imagine further that the rod is bonded to the sleeve by
`potting resin 16i, which is sandwiched between the rod and
`the sleeve and fills any parts of the bore not taken up by the
`inserted rod. The intended function of the system is for the
`tensile load carried by the rod to be transferred to and fully
`taken up by the shank 14i, the load transfer occurring across
`the layer of potting resin and along the length of the bore lli
`in which the rod is received.
`Of course it is intended that the tensile loading of the rod
`will vary across a range of values. Tensile loading changes
`in response to the different loads imposed on the rod by
`many variables, for example by different wind, sea, and
`maneuvering conditions. The loading of the rod will not
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`Page0000008
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`US 6,886,484 B2
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`5
`jump instantaneously from zero to a level at or near the full
`working load, but rather applied loads will rise, whether
`precipitously or relatively slowly or a mixture of both,
`through a continuum of load values from zero toward the
`working load—the maximum tensile load (expressed in
`units of force, such as pounds) for which the system is
`designed. The applied loads also return to or toward zero
`through the same continuum of values.
`As the loading of the rod increases, the load is transferred
`through the resin layer and is taken up by the shank sleeve
`12i by elastic deformation of the latter. Elastic deformation
`of the sleeve should ideally take place along the entire length
`of the bore, but occurs at some points before others, or
`occurs to a greater degree at some points than at others,
`under most practical conditions.
`The working load for the rod will need to be considerably
`under its breaking strength, to assure tolerance of cyclic
`fatigue loading, long-term fatigue loading, ultraviolet and
`weathering, impact wear, and chafe wear. While some higher
`end composite materials might allow selection of a working
`load of say about 150,000 to 180,000 psi, a typical reason-
`able working load selection for lower end composite mate-
`rials may be say from 80,000 to 100,000 psi. Suppose a rod
`material is used for which one of these working loads is
`selected. Further, assume the load-transfer intensity capacity
`of the resin (expressed in units of force per unit area, such
`as psi) is such that it substantially exceeds the average load
`transfer intensity from the rod to the resin at working load.
`(Average load transfer intensity can be readily calculated as
`a function of working stress, buried length and rod radius.
`"Load-transfer intensity capacity of the resin" is intended as
`a shorthand reference to the highest intensity of load that the
`combined rod, resin layer, and sleeve have the capacity to
`transfer between the rod and the sleeve, and will be deter-
`mined by the lowest of the following load-transfer intensity
`capacities: that of the resin itself, that of the resin/sleeve
`interface, and that of the resin/rod interface, for the specific
`rod, resin and sleeve materials.)
`Further imagine that the fitting is made of stainless steel
`whose yield strength is such that the fitting requires a
`minimum of three times the cross-sectional area of the rod
`to keep the fitting stress below the yield strength of the steel,
`which is a realistic reflection of actual relationships and
`requirements in the field. That cross-sectional area would
`have to be provided at the plane A—A seen in FIG. 1 and,
`if the potting resin 16i took up no thickness, would geo-
`metrically require that the diameter of the shank at that point
`be double that of the rod to keep the fitting stress below yield
`strength. The shank diameter requirement would actually be
`somewhat higher, taking into account that the potting resin
`does take up some thickness.
`Suppose then that these reasonable selections and dimen-
`sional relationships are established. Even so, the imagined
`device of FIG. 1 will not operate satisfactorily under most
`practical circumstances. Instead the system will fail under
`full working load either immediately, or in relatively short
`time.
`It is believed that failure under such circumstances is due
`to "load dumping," that is, local load-transfer intensity
`values rising above the load-transfer intensity capacity of the
`potting resin at the entry point region where the rod enters
`the shank, or at the end point region where the rod terminates
`or both, for the following reasons: With reference to the
`entry point region, since the wall thickness of the sleeve 12i
`is at the same high value at the entry end of the bore as at
`other locations along the bore, the sleeve is no more stretchy
`
`5
`
`1
`
`15 (cid:9)
`
`6
`(no less stiff) at the entry point 19i than it is at other locations
`along the bore. The sleeve therefore strongly resists elastic
`deformation, causing local stress intensity to rise rapidly as
`the applied load increases. Nor is the situation relieved by
`the occurrence of sufficient elastic deformation at other
`locations on the sleeve, where the sleeve wall is equally
`thick. Elastic deformation at such other locations cannot
`occur in sufficient degree to prevent the local stress intensity
`at the entry end region from escalating beyond the load-
`transfer intensity capacity of the resin, so that local defects
`in resin bonding occur. Such local de-bonding can then
`propagate either immediately, or during fatiguing in the
`course of repeated cycles of loading and unloading, or after
`long-period loading, leading to overall failure.
`Characteristic of such a load dumping situation is the
`relatively great elevation of load-transfer intensity values (in
`pounds per square inch or in other units of force per unit
`area) at the entry point region above load-transfer intensity
`values at deeper regions within the bore, including adjacent
`20 regions just a little further in than the region of the entry
`point.
`With reference to the end point region of the rod, a similar
`situation applies, but here instead of the relatively stiff end
`of the sleeve furnishing strong resistance to elastic
`25 deformation, it is the relatively stiff end of the rod that does
`so. The rod diameter is at the same full value at the end point
`region of the rod as it is at other locations along the bore. The
`end point region of the rod therefore strongly resists elastic
`deformation, i.e. stretching, when responding to the stress
`30 imposed on it by the shank 14i under applied loads, causing
`local stress intensity to rise as the applied load increases.
`The situation is not relieved by the occurrence of suffi-
`cient elastic deformation at other locations on the rod, where
`the rod diameter is equally high. Elastic deformation at such
`35 other locations cannot occur in sufficient degree to prevent
`the local stress intensity at the end point region of the rod
`from escalating beyond the load-transfer intensity capacity
`of the resin, so that local failures in resin bonding occur.
`Such local de-bonding can then propagate either
`40 immediately, or during fatiguing in the course of repeated
`cycles of loading and unloading, or after long-period
`loading, leading to overall failure.
`Characteristic of the load dumping situation just described
`is the relatively great elevation of load-transfer intensity
`45 values at the end point region of the rod above load-transfer
`intensity values at less-deep regions within the bore, includ-
`ing adjacent regions just slightly less deep than the end point
`region.
`FIG. 2A illustrates in rudimentary form an embodiment of
`so the invention whose features may be compared or contrasted
`with those of the hypothetical terminal system of FIG. 1. In
`the system of FIG. 2A, the diameter and material of the
`round pultruded rod is the same as in the FIG. 1 system, and
`the same is true of the shank diameter and material. Pul-
`55 truded tension rods of round cross-section as referred to in
`this disclosure were obtained from Avia Sport Composites
`Inc., 71 3rd Street S.E., Hickory, N.C. 28602 (web address:
`aviasport.net ) where they are available as
`"Graphlite®MicroCarbon Rod" in "Standard Modulus" or
`60 "Intermediate Modulus." The former were used in tests.
`Pultruded tension rods of round cross-section in 1/4" size
`were also obtained from Strongwell Inc., 400 Common-
`wealth Ave., Bristol, Va. 24203 (web address:
`strongwell.com). Although shank material is preferably
`65 6AL4V titanium, stainless steel alloys ASTM 304 or 316
`may be used. Assume the latter is used as the shank material
`for both the systems of FIG. 1 and FIG. 2A.
`
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`US 6,886,484 B2
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`7
`The potting resin is also assumed to be the same for the
`systems of FIG. 1 and FIG. 2A, and for the most part the
`resin of the system of FIG. 2A is of the same wall thickness
`as in the FIG. 1 system. Potting resin 16a, and the potting
`resins of the other embodiments of the terminal system of
`the invention, are adhesive type bonding agents that chemi-
`cally bond to the composite rod. A typical plastic adhesive
`such as epoxy, polyurethane, phenolic, silicone, or other
`type binder resin may be used. The binder system may also
`have filler introduced which may help in forming a thicker
`or more viscous binder, or aid in other properties of the
`binder such as thermal expansion, density, hardness,
`toughness, reduced bond line thickness, or some other
`desirable property of the system.
`A suitable potting resin, obtained from Master Bond Inc.,
`154 Hobart Street, Hackensack, N.J. 07601 (web address:
`masterbond.com), is Master Bond Grade "Supreme 10HT"
`from their line of "One Component Epoxy Adhesives,
`Sealants, Coatings, Encapsulants, & Potting Compounds."
`This is a single part or premixed epoxy and will function at
`temperatures up to 400 degrees F. It is also a paste type
`epoxy, so is easy to inject and is not watery in its flow. A
`negative is that this product must be heat cured for 1 hour at
`250 degrees F. or 45 minutes at 300 degrees F.
`Potting resin and hardener used for some testing may be
`obtained from the line of "West System" epoxy products of
`Gougeon Bros. Inc., 100 Patterson Ave., P.O. Box 908, Bay
`City, Mich. 48707 (web address: gougeon.com), specifically
`their. "105 Epoxy Resin" and "205 Fast Hardener." While
`the resulting cured resin layer is suitable for test purposes,
`it is not suitable for manufacture because the product must
`be mixed in two parts and softens at 120-140 degrees F.
`In the system of FIG. 2A, as in the imaginary construction
`of FIG. 1, the rod, in this case rod 10a, may be of round
`cross-section and is received in the bore Ha of the sleeve
`12a, extending into the sleeve past the rod entry point 19a.
`As in the imaginary construction of FIG. 1, the sleeve is
`formed as part of the shank, in this case 14a, of a terminal
`fitting, in this case again an eye. As before, the eye may have
`a threaded bore (not shown) in which exterior threading (not
`shown) on the shank is received, the eye being turned down
`tightly on the shank to form a fitting, in this case the eye. Or
`the shank and eye can be joined by other means, for example
`adhesive or welding. Or the shank and the eye can be
`integrally formed from a single piece of material. Or, the
`shank can join to or be integrally formed with parts other
`than an eye to provide other common or known types of
`fittings, such as forks, tees, studs, nailheads, and stemballs
`that interconnect with other elements to form eye/jaw
`toggles, jaw/jaw toggles, stud terminals, swivel bails, or
`other connecting or tie-down devices, or the shank can be
`somewhat elongated and threaded for a required adjusting
`distance to function as part of a turnbuckle connection, or
`the shank can form part of a fitting for still other kinds of
`connections and tie-downs, for example but without
`limitation, nail head, stemball, cylinder terminal, shroud
`terminal, t-ball terminal, shackle, wedge, and in general all
`those kinds of fittings which in present practice are swaged
`to or otherwise terminate metal rigging lines.
`The same is true of the shanks of all herein disclosed
`embodiments of the terminal system of the present inven-
`tion. Such kinds of fittings may be referred to as terminal
`fittings.
`The rod 10a is bonded to the sleeve by the potting resin
`16a, which is sandwiched between the rod and the sleeve
`and fills any parts of the bore not taken up by the rod. It is
`
`5 (cid:9)
`
`45
`
`8
`to be noted that the radial thickness (wall thickness) of the
`layer of resin is relatively uniform along a majority of the
`total length of the bore Ha as compared to the varying wall
`thickness of the sleeve 12a along the same length.
`As described so far, the system of FIG. 2A is similar to the
`imaginary system of FIG. 1. However, in the system of FIG.
`2A, the end portion 18a of the sleeve is continuously tapered
`from a relatively thin sleeve wall thickness at the entry point
`region of the rod to progressively greater wall thicknesses at
`10 regions deeper within the bore. While any tapering, as depth
`within the bore increases, is generally in the direction of
`increasing wall thickness of the wall of sleeve 12a, conti-
`nuity of tapering may be interrupted at segments along the
`length of the bore, such as the central region 20a. Inwardly
`15 or still deeper within the bore beyond this central region,
`continuous tapering in the direction of increasing sleeve wall
`thickness resumes and extends down toward the inner end of
`the bore Ha.
`At the same time, the end of the rod 10a is continuously
`20 tapered from a relatively small diameter at the end point
`region of the rod (or