O
`(12) Ulllted States Patent
`DeFranks et al.
`
`(54) MICROALLOYED SPRING
`
`(75)
`
`Inventors: Michael S. DeFranks, Decatur, GA
`(US)? William J“ R"adY>At1am"‘= GA
`(US); Jeremy Lynn, Newnan, GA (US)
`
`(73) Assignee: Dreamwel], Ltd., Las Vegas,NV (US)
`( * ) Notice:
`Subject to any disclaimer the term of this
`.
`’.
`%a‘Se‘g 1155ftXte‘;deg9°7rd‘;dJ“Sted under 35
`'
`'
`‘
`(b) y
`yS'
`(21) Appl- No.: 12/106.216
`.
`Flledi
`
`AP“ 18= 2008
`
`(22)
`
`(65)
`
`Prior Publication Data
`
`US 2009/0261518 A1
`
`Oct. 22, 2009
`
`52
`
`(51)
`
`Int. Cl.
`F16F 1/06
`(2006.01)
`U.S. Cl.
`) USPC ............ 267/166; 267/148; 267/149; 267/169
`(
`(58) Field of Classification Search
`USPC ................ .. 267/166, 169, 149, 148; 428/592,
`428/457, 681-685; 420/90-93
`See application file for complete search history.
`
`US008474805B2
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 8,474,805 B2
`Jul. 2, 2013
`
`........... .. 148/411
`
`7/1986 lkushima et al.
`4,599,119 A *
`10/1989 Wan
`4,875,933 A
`"""""""“ 148/333
`£1’: it 31'
`2 *
`................ 439/66
`7/1996 Tmgllli
`5,540,593 A *
`.. 428/544
`........ ..
`1/2000 Aoki etal.
`6,017,641 A *
`
`...... .. 420/91
`..
`6,322,747 B1* 11/2001 Fukuzumi et al.
`............-- 423/600
`*
`filiiiiet 31
`as mura et
`.
`1
`Earlzirl
`'
`t
`.
`1/2007 Gi:dne;e1a1.
`(Continued)
`FOREIGN PATENT DOCUMENTS
`0647725
`4/1995
`1577411 A1
`9/2005
`1698712 A1
`9/2006
`
`,
`
`,
`
`,
`,
`7,168,117 B2
`
`EP
`EP
`EP
`
`OTHER PUBLICATIONS
`
`Staiger, M.P., et al., “Microalloying with Titanium to Improve
`Drawability in Low Carbon Wire-Red Steels,” Materials Science
`Forum, 284-2862575-582 (1998).
`.
`(commued)
`Primary Examiner _ Bradley King
`.
`.
`.
`Asszstant Exammer — Mahbubur Rashid
`74 A
`A
`F,
`C
`)
`nomey’ gem’ or Wm _ amor
`
`C lb
`0 um
`
`LLP
`
`(
`
`ABSTRACT
`(57)
`The systems and methods described herein include inner-
`spring assemblies or innerspring cores for use with cushion-
`ing articles S11ChaSmattreSSeS~TT1eiI1I1erSPIiI1gC0remaYhaV€
`one or more coil springs formed fromahigh-carbon steel wire
`alloyed with one or more suitable alloying elements such as
`titanium and copper and capable ofimparting greater strength
`and durability to the innerspring core
`'
`
`20 Claims, 7 Drawing Sheets
`
`/ 100
`/
`
`/ 102
`
`
`
`Leggett & Platt v. Simmons Bedding et al.
`Ex. 1001 /Page 1 of15
`
`(56)
`
`References Cited
`
`US. PATENT DOCUMENTS
`1,914,083 A *
`6/1933 Eaton .......................... .. 267/166
`4,072,510 A
`2/ 1978 Smellie et al.
`4«191a053 A "1
`3/1980 H3“ 6! 31-
`~~~~~~~~~~~~~~~~~~~ -~ 374/112
`4365579 A ,,
`5/1981 Ohashl et a1‘
`4,445,694 A
`5/ 1984 Flaherty ...................... .. 277/312
`4,462,651 A *
`7/1984 McGaff1gan ..
`439/161
`4,473,217 A *
`9/1984 Hashimoto
`. 267/149
`4,490,975 A *
`1/1985 Yaeger et al.
`..... .. 60/527
`
`
`
`.
`
`

`
`US 8,474,805 B2
`Page 2
`
`2003/0172531
`2004/0025987
`2004/0079067
`2004/01 58929
`200 5/00053 54
`200 5/0055778
`2006/006 5334
`2007/0118987
`
`U.S. PATENT DOCUMENTS
`A1
`9/2003
`A1
`2/2004
`A1
`4/2004
`A1
`8/2004
`A1
`1/2005
`A1
`3/2005
`A1
`3/2006
`A1
`5/2007
`
`Bhagwat et al.
`Bhagwat et al.
`Yoshikawa et al.
`Gladney
`Gladney et al.
`Kuchel
`Bhagwat et al.
`Gladney et al.
`
`OTHER PUBLICATIONS
`
`International Search Report for PCT/US2009/041141 dated Jul. 16,
`2009.
`
`Office Action issued in European Patent Application No. 09733128.
`4-2424, dated Jan. 21, 2013; 5 pages.
`
`* cited by examiner
`
`Ex. 1001 / Page 2 of 15
`
`

`
`U.S. Patent
`
`Jul. 2, 2013
`
`Sheet 1 of7
`
`US 8,474,805 B2
`
`/ 100
`
`102
`
`104
`
`FIG. 1
`
`Ex. 1001 /Page 3 of 15
`
`

`
`U.S. Patent
`
`Jul. 2, 2013
`
`Sheet 2 of7
`
`US 8,474,805 B2
`
`/ 200
`
`FIG. 2
`
`Ex. 1001 / Page 4 of 15
`
`

`
`U.S. Patent
`
`Jul. 2, 2013
`
`Sheet 3 of7
`
`US 8,474,805 B2
`
`/ 300
`
`304
`
`FIG. 3A
`
`Ex. 1001 /Page 5 of 15
`
`

`
`U.S. Patent
`
`Jul. 2, 2013
`
`Sheet 4 of7
`
`US 8,474,805 B2
`
`/ 350
`
`FIG. 3B
`
`Ex. 1001 / Page 6 of 15
`
`

`
`U.S. Patent
`
`Jul. 2, 2013
`
`Sheet 5 of7
`
`US 8,474,805 B2
`
`400
`
`41 2
`
`41 0
`
`408
`
`405
`
`404 —
`
`4
`
`H
`
`
`
`,4 A-§..o_.x.-gt.-442%;-Tam-gr;-Tgv
`
`.44
`
`¢T¢T¢T¢7¢T¢7¢V
`
`FIG. 4
`
`Ex. 1001 /Page 7 of 15
`
`

`
`U.S. Patent
`
`Jul. 2, 2013
`
`Sheet 6 of7
`
`US 8,474,805 B2
`
`500 \\\
`
`PROVIDE ALLOYED RODS
`
`
`EXPOSE ALLOYED RODS
`TO ONE OR MORE
`
`HEAT TREATMENTS
`
`
`
`
`
`ARE
`
`MORE
`
`
`
`HEAT TREATMENT
`
`
`CYCLES
`
`
`NEEDED?
`
`NO
`
`DRAW WIRE FROM
`
`THE TREATED RODS
`
`\ 508
`
`ARE
`
`
`MORE
`
`
`
`CYCLES
`NEEDED?
`
`502
`
`— 504
`
`\ 506
`
`510
`
`514
`
`516
`
`
`
`
`
`EXPOSE WIRE
`
`TO ONE OR MORE
`
`HEAT TREATMENT
`
`HEAT TREATMENTS
`
`
`
`512
`
`NO
`
`GENERATE COIL SPRING
`
`
`
`MORE
`EXPOSE COIL SPRING
`
`HEAT TREATMENT
`TO ONE OR MORE
`
`HEAT TREATMENTS
`CYCLES
`
`NEEDED?
`
`
`
`
`ARE
`
`FIG. 5
`
`Ex. 1001 /Page 8 of 15
`
`

`
`U.S. Patent
`
`Jul. 2, 2013
`
`Sheet 7 of7
`
`US 8,474,805 B2
`
`ETCHANT: NITAL
`
`MAGNIFICATION: 1,000X
`
`FIG. 6A
`
`ETCHANT: NTAL
`
`‘
`
`‘ MAGNIFICATION: 1,00
`
`Ex. 1001 /Page 9 of 15
`
`

`
`1
`MICROALLOYED SPRING
`
`FIELD OF THE INVENTION
`
`This invention generally relates to coil springs for use with
`an innerspring core in cushioning articles such as mattresses.
`
`BACKGROUND OF THE INVENTION
`
`A standard mattress assembly includes one or more layers
`of padding disposed on an innerspring core. Typically, the
`innerspring core includes a plurality of coil springs that are
`closely packed together in an array having a generally rect-
`angular shape in plan with the ends of the springs lying in a
`common plane. The coil springs have longitudinal axes ori-
`ented parallel to one another. Conventionally, each spring is
`manufactured from a single, solid, coiled steel wire.
`During its lifetime, mattresses, and particularly the inner-
`spring core, endures significant stresses from daily use. Such
`repetitive daily use causes the coil springs in these inner-
`spring cores to undergo many cycles of compression and
`release. Consequently, physical characteristics of these
`springs, such as coil length and pitch, begin to change over
`time. Moreover, the springs lose some tensile strength and
`become generally weaker.
`To increase the durability and comfort ofthese mattresses,
`manufacturers include one or more additional layers of sup-
`port and padding above and below the innerspring core. These
`additional layers help maintain the integrity of the inner-
`spring core by redistributing some of the forces and stresses
`away from the coil springs. However, the additional layers
`add extra bulk and weight to the mattress assembly.
`Other manufacturers have experimented with different
`shapes and arrangements of these coil springs, and have also
`attempted to add one or more strands to the coil springs to
`strengthen the innerspring core. However, these techniques
`are not as effective in redistributing the stresses and inevitably
`require additional layers of padding.
`Accordingly, there is a need for a cushioning article con-
`figured with a stronger and more durable innerspring core
`while keeping the weight and size to a minimum.
`
`SUMMARY
`
`The systems and methods described herein include inner-
`spring assemblies or innerspring cores for use in cushioning
`articles such as mattresses. The innerspring core may have
`one or more coil springs that are relatively light, yet stronger
`and more durable than traditional coil springs. The coil
`springs may be formed from a high-carbon steel wire alloyed
`with one or more suitable alloying elements such as titanium
`and copper and capable of imparting greater strength and
`durability to the innerspring core.
`For purposes of clarity, and not by way of limitation, the
`systems and methods may be described herein in the context
`of providing innerspring cores for mattresses. However, it
`will be appreciated that the principles described herein may
`be adapted to a wide range of applications. For example, the
`principles ofthis disclosure may be applied to couches where
`a cushion is afiixed to a larger assembly. In addition, the
`principles may be applied to chairs, loveseats, sofas, daybeds,
`automotive seats, crib mattresses, fold-out couches, and fold-
`ing mattresses. More generally, the systems described herein
`may be employed in any environment where it is desirable to
`provide cushioning support.
`More particularly, in one aspect, the systems and methods
`described herein include coil springs for use with an inner-
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
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`50
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`55
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`60
`
`65
`
`US 8,474,805 B2
`
`2
`
`spring assembly in a cushioning article. The coil springs may
`comprise a steel wire coiled into a helical spring and alloyed
`with at least one alloying element. In certain embodiments,
`the steel wire comprises a high carbon steel wire. The high
`carbon steel wire may include carbon that is from about 0.55
`to about 0.99 weight percent ofthe spring. In certain embodi-
`ments, the spring includes about four times more carbon than
`at least one of the alloying elements. The spring may include
`about ten times more carbon than at least one of the alloying
`elements. The spring may include any ratio of carbon to the
`alloying element depending on the application without
`departing from the scope of the invention.
`The alloying elements may include at least one oftitanium,
`manganese, vanadium, chromium, niobium, nickel, molyb-
`denum, and copper. The alloying element may be from about
`0.001 to about 2 weight percent of the spring. The alloying
`element may include titanium that is from about 0.001 to
`about 0.1 weight percent of the spring. The titanium may be
`from about 0.001 to about 0.01 weight percent of the spring.
`In certain embodiments, the alloying element may include
`copper that is from about 0.1 to about 0.3 weight percent of
`the spring. The alloying elements may include titanium and
`copper, such that the spring includes from about 10 to about
`30 times more copper than titanium.
`In certain embodiments, the alloying elements includes
`manganese that is from about 0.3 to about 0.9 weight percent
`of the spring 100 and/or phosphorous that is less than about
`0.04 weight percent and/or sulfur that is less than about 0.05
`weight percent and/or silicon that is less than about 055
`Weight percent and/or lead that is from about 0.15 to about
`0.35 weight percent and/or boron that is from about 0.0005 to
`about 0.003 weight percent and/or chromium that is from
`about 0.001 to about 2 weight percent and/or nickel that is
`from about 0.001 to about 2 weight percent and/or molybde-
`num that is from about 0.001 to about 1.15 weight percent
`and/or niobium that is from about 0.001 to about 0.1 weight
`percent and/or aluminum that is about 0.003 weight percent
`and/or zirconium that is less than about 0.15 weight percent
`and/or vanadium that is from about 0.001 to about 023
`
`Weight percent of the spring.
`In certain embodiments, the steel wire includes a plurality
`ofstrands. The plurality of strands may be twisted together. In
`particular, the plurality of strands may include two, three or
`more strands twisted together. In certain embodiments, each
`of the strands has a helical twist with a direction that is
`
`opposite to a twist direction of the stranded coil spring. The
`plurality of strands may be joined at least at respective ends of
`the spring. In certain embodiments, the plurality of strands all
`have approximately equal outside diameters. Alternatively, at
`least one of the plurality of strands may have an outside
`diameter different from that of at least one other of the plu-
`rality of strands.
`the coil spring comprises an
`In certain embodiments,
`encasing material formed around the helical spring. The
`encasing material may form a pocket around the spring. The
`encasing material may include at least one of polyester,
`polypropylene and foam such as polyurethane foam, polyeth-
`ylene foam and latex foam.
`In certain embodiments, the steel wire has a diameter from
`about 0.04 inches to about 0.11 inches. The spring may have
`a free height, e.g., uncompressed, from about 3.5 inches to
`about 13.5 inches. In certain embodiments, the coil spring
`may include an upper substantially frustoconical spring coil
`portion, and a lower substantially cylindrical spring portion
`disposed below the upper spring portion. The coil spring may
`be configured such that the upper portion may compress
`substantially before the lower portion begins to compress.
`Ex. 1001 IPage 10 of 15
`
`

`
`US 8,474,805 B2
`
`3
`the systems and methods described
`In another aspect,
`herein include innerspring assemblies having a plurality of
`spring coils. Ir1 such an aspect, at least one spring coil may
`comprise a high-carbon steel wire coiled into a helical spring
`and alloyed with at least one of titanium, manganese, vana-
`dium, chromium, nickel, molybdenum, and copper. The
`alloying element may be from about 0.001 to about 1 weight
`percent of the spring. In certain embodiments the spring coil
`may include at least one of an encased coil, an open coil and
`a continuous coil.
`In yet another aspect, the systems and methods described
`herein include cushioning articles. The cushioning articles
`may comprise an innerspring core including a plurality of
`spring coils, at least one spring coil having a high-carbon steel
`wire coiled into a helical spring and alloyed with titanium and
`copper. In certain embodiments, the cushioning article further
`comprises at least one layer of upholstery disposed on the
`innerspring core. The cushioning article may include one or
`more backing layers disposed on the innerspring core. Addi-
`tionally and optionally, the cushioning article may include
`one or more layers offoam, fiberbatting, down, natural fibers,
`feathers and hair disposed on the innerspring core.
`In another aspect,
`the systems and methods described
`herein include methods of manufacturing a coil spring. The
`methods may comprise providing alloyed rods including
`high-carbon steel and at least one of titanium, manganese,
`vanadium, chromium, nickel, molybdenum, and copper. The
`methods may further include exposing the alloyed rods to one
`or more cycles of heat-treatment, drawing a wire from the
`heat-treated alloyed rods, and generating one or more helical
`springs by passing the drawn wire through a coil winder. In
`certain embodiments, the heat-treatrnent includes at least one
`of annealing, hardening, precipitation strengthening, temper-
`ing, quenching and austenizing. In certain embodiments, the
`method filrther comprises exposing the drawn wire to one or
`more cycles of heat-treatment. Additionally and optionally,
`the method may comprise exposing the one or more helical
`springs to one or more cycles of heat-treatment.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The foregoing and other objects and advantages of the
`invention will be appreciated more fully from the following
`further description thereof, with reference to the accompany-
`ing drawings wherein;
`FIG. 1 depicts a microalloyed coil spring, according to an
`illustrative embodiment of the invention.
`
`FIG. 2 depicts a muitistranded microalloyed coil spring,
`according to an illustrative embodiment of the invention.
`FIG. 3A depicts an encased microalloyed coil spring,
`according to an illustrative embodiment of the invention.
`FIG. 3B depicts an encased asymmetrical microalloyed
`coil spring, according to an illustrative embodiment of the
`invention.
`
`FIG. 4 depicts a cushion assembly having an innerspring
`core, according to an illustrative embodiment of the inven-
`tion.
`FIG. 5 is a flow chart depicting a method ofmanufacturing
`a microalloyed coil spring, according to an illustrative
`embodiment of the invention.
`
`FIGS. 6A and 6B depict a transverse microscopic cross
`section of a steel coil spring and an exemplary microalloyed
`coil spring, respectively.
`
`DETAILED DESCRIPTION OF THE
`ILLUSTRATED EMBODIMENTS
`
`To provide an overall understanding of the invention, cer-
`tain illustrative embodiments will now be described, includ-
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4
`
`ing a mattress having at least one microalloyed coil spring.
`However, the embodiments set out below are merely for the
`purpose of illustration and it will be understood by one of
`ordinary skill
`in the art
`that the systems and methods
`described herein may be adapted and modified for other suit-
`able applications and that such other additions and modifica-
`tions will not depart from the scope hereof.
`FIG. 1 depicts a microalloyed coil spring 1 00, according to
`an illustrative embodiment of the invention. The coil spring
`100 includes a wire 102 that is coiled into a helical shape. The
`free height of the spring 100 is the height of the spring 100
`when little or no force is applied to it and each ofthe coils 104
`are at a resting state. In certain embodiments, the spring 100
`has a free height from about 3.5 inches to about 13.5 inches.
`The wire 102 may have a diameter from about 0.04 inches to
`about 0.11 inches. The wire 102 may be formed from a steel
`wire alloyed with one or more alloying elements.
`In certain embodiments, the wire 102 comprises high car-
`bon steel. Carbon content in the high carbon steel wire 102
`may range from about 0.5 5 to about 0.99 weight percent ofthe
`spring 100. The wire 102 may include one or more high
`carbon steel grades standardized by the American Iron and
`Steel Institute (“AISI”) including at least one of AISI 1055,
`AISI 1059, AISI 1060, AISI 1064, AISI 1065, AISI 1069,
`AISI 1070, AISI 1074, AISI 1075, AISI 1078, AISI 1080,
`AISI 1084, AISI 1085, AISI 1086,AISI 1090 andAISI 1095.
`In other embodiments, the wire 102 may include one or more
`high carbon steel grades described under the Unified Num-
`bering System (“UNS”) including at
`least one of UNS
`G10740, UNS G10750, and UNS G15720.
`The wire 102 may include an alloying element such as
`titanium alloyed with high carbon steel. The titanium in the
`wire 102 may range from about 0.001 to about 0.01 weight
`percent of the spring 100. In certain embodiments, the tita-
`nium may range from about 0.001 to about 0.1 weight percent
`ofthe spring 100. Generally, titanium may comprise less than
`about 0.1 weight percent ofthe spring 100. Not to be bound by
`theory, but generally, high carbon steel tends to have a dense
`microstructure with limited interstitial volume. Adding rela-
`tively small amounts of titanium may be advantageous
`because the titanium may form an interstitial alloy with the
`high carbon steel; the titanium atoms may fill some of the
`interstitial volume, thereby strengthening the wire 100. In
`certain embodiments, the titanium may form a substitutional
`alloy with the high carbon steel; the titanium atoms may
`substitute one or more carbon atoms in the crystal structure.
`Current-day steel springs do not include titanium because it
`tends to increase the spring’s brittleness. Consequently,
`although the steel-titanium alloy is stronger, it is also more
`difiicult to draw into a wire, let alone coil into a spring. The
`systems and methods described herein overcome these limi-
`tations by combining one or more other alloying elements
`such as copper and/or subjecting the alloy to heat treatments.
`As will be described in more detail later with reference to
`FIGS. 5, 6A and 6B, the microalloyed high carbon steel wire
`102 may be subject to one or more heat treatments to help
`modify the wire’s 102 phase morphology and/or one or more
`physical properties.
`In certain embodiments, the wire 102 may comprise one or
`more titanium-iron alloy grades selected from a group con-
`sisting ofASTM A514 Type B, ASTMA514 Type D, ASTM
`A514 Type E, ASTM A514 Type L, ASTM A517 Type B,
`ASTMA517 Type D,ASTMA517 Type E, ASTMA517 Type
`L, ASTM A538 Type A, ASTM A538 Type B, ASTM A538
`Type C, ASTM A562, ASTM A588 Type G, ASTM A588
`Type H, ASTM A588 Type J, ASTM A590, ASTM A656
`EX. 1001 IPage 11 of 15
`
`

`
`US 8,474,805 B2
`
`5
`Grade 2, ASTMA715 Grade 1, ASTMA715 Grade 4, ASTM
`6512, ASTM 6514, ASTM 6520, and ASTM 6521.
`In certain embodiments, the wire 102 includes one or more
`additional alloying elements capable of modifying one or
`more physical properties of the wire and consequently, the
`performance of the spring 100. Depending on the size of its
`atoms, the alloying elements may form substitutional alloys
`and/or interstitial alloys. In substitution alloys, the atoms of
`the components may be approximately the same size and the
`various atoms are simply substituted for one another in the
`crystal structure. Interstitial alloys occur when the atoms of
`one component may be substantially smaller than the other
`and the smaller atoms fit into the spaces (interstices) between
`the larger atoms. As an example, the wire 102 may be alloyed
`with copper. In certain embodiments, the wire 102 comprises
`copper that is from about 0.1 to about 0.3 weight percent of
`the spring 100. In another embodiment, the wire 102 com-
`prises copper that is about 0.55 weight percent of the spring
`100. The wire 102 may include from about 10 to about 30
`times more copper than titanium. The wire 102 may include
`any desirable amount of copper to help improve its drawabil-
`ity (ductility).
`Coil springs formed from titanium and copper alloyed steel
`wire 102 generally have a longer working life than traditional
`steel springs. Particularly, the performance of springs may be
`estimated by analyzing the decrease in free height of the
`spring after a certain number of compression cycles. During
`their lifetime, one or more coil springs in a cushioning article
`lose some of their free height resulting in areas of shorter
`springs. This creates an uneven surface on the cushioning
`article. However, as seen below in Table 1, afier about two
`million cycles, the titanium based microalloyed coil spring
`100 loses about 15% less free height than a traditional steel
`coil spring.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`6
`in Table 1 were compression tested to 2,000,000 cycles at
`50% compression and 190 strokes per minute. During, test-
`ing, the free height (or free length) ofthe coils were measured
`at various times.
`
`In other embodiments, the steel wire 102 may be alloyed
`with other alloying elements including at least one of man-
`ganese, phosphorous, sulfur, silicon, lead, boron, aluminum,
`zirconium, vanadium, chromium, niobium, nickel and
`molybdenum. Generally, the alloying element may be from
`about 0.001 to about 2 weight percent of the spring 100.
`Specifically, in certain embodiments, the steel wire 102 may
`include manganese that is from about 0.3 to about 0.9 weight
`percent of the spring 100 and/or phosphorous that is less than
`about 0.04 weight percent and/or sulfur that is less than about
`0.05 weight percent and/or silicon that is less than about 055
`Weight percent and/or lead that is from about 0.15 to about
`0.35 weight percent and/or boron that is from about 0.0005 to
`about 0.003 weight percent and/or chromium that is from
`about 0.001 to about 2 weight percent and/or nickel that is less
`than about 10 weight percent and/or molybdenum that is less
`than about 1.15 weight percent and/or niobium that is less
`than about 0.1 weight percent and/or aluminum that is about
`0.003 weight percent and/or zirconium that is less than about
`0.15 weight percent and Vanadium that is less than about 0.03
`weight percent ofthe spring 100. In certain embodiments, the
`wire 102 may include about four times more carbon that at
`least one of the alloying elements.
`Material selection for the wire 102 may be based on a
`number of factors,
`including temperature range,
`tensile
`strength, elastic modulus, fatigue life, corrosion resistance,
`cost, etc. One or more alloying elements may be combined as
`desired to modify the aforementioned factors. In certain
`embodiments, electronegativity or electropositivity of an
`alloying element may be leveraged to scavenge and remove
`
`TABLE 1
`
`# Cycles 8" to 5"
`
`Specimen #
`
`10
`
`100
`
`35K 70K
`1,000 2,000 3,000 4,000 5,000
`Free height (in)
`
`100K 500K 1 M 1.5 M 2 M
`
`9.65
`9.65
`9.72
`9.69
`9.53
`9.61
`9.64
`
`9.65
`9.65
`9.72
`9.69
`9.53
`9.61
`9.64
`
`9.57
`9.57
`9.53
`9.61
`9.57
`9.53
`9.56
`
`9.57
`9.57
`9.53
`9.57
`9.49
`9.49
`9.53
`
`9.57
`9.57
`9.53
`9.57
`9.49
`9.49
`9.53
`
`Std.
`
`9.53
`9.57
`9.53
`9.57
`9.53
`9.53
`9.53
`9.53
`9.45
`9.49
`9.49
`9.49
`9.51
`9.53
`Ti-based
`
`9.53
`9.49
`9.53
`9.53
`9.45
`9.49
`9.50
`
`9.53
`9.49
`9.53
`9.53
`9.45
`9.49
`9.50
`
`9.53
`9.49
`9.53
`9.53
`9.45
`9.49
`9.50
`
`9.53
`9.49
`9.53
`9.53
`9.45
`9.49
`9.50
`
`9.49
`9.45
`9.45
`9.41
`9.41
`9.45
`9.44
`
`9.49
`9.45
`9.45
`9.45
`9.41
`9.45
`9.45
`
`9.49
`9.45
`9.45
`9.45
`9.41
`9.45
`9.45
`
`10.08 10.08 10.08 10.08 10.08 10.08 10.08 10.08 10.08
`9.92
`9.92
`9.88
`9.88
`9.88
`9.88
`9.84
`9.84
`9.84
`10.39 10.39 10.28 10.28 10.24 10.24 10.16 10.16 10.16
`9.88
`9.88
`9.84
`9.80
`9.80
`9.80
`9.80
`9.80
`9.80
`10.00 10.00
`9.96
`9.96
`9.92
`9.92
`9.88
`9.88
`9.88
`10.04 10.04 10.00
`9.96
`9.92
`9.92
`9.88
`9.88
`9.88
`10.05
`10.05 10.01
`9.99
`9.97
`9.97
`9.94
`9.94
`9.94
`
`10.08 10.08 10.04 10.04
`9.84
`9.84
`9.80
`9.80
`10.16 10.16 10.12 10.12
`9.80
`9.80
`9.76
`9.76
`9.88
`9.88
`9.76
`9.76
`9.88
`9.88
`9.84
`9.84
`9.94
`9.94
`9.89
`9.89
`
`10.04
`9.80
`10.12
`9.76
`9.76
`9.84
`9.89
`
`1
`2
`3
`4
`5
`6
`Avg.
`
`1
`2
`3
`4
`5
`6
`Avg.
`
`Six traditional coil springs (“Std.” 1-6) and six titanium
`based microalloyed coil springs (“Ti-Based” 1-6) were
`tested. The traditional springs had an average initial free
`height of about 9.64". The miroalloyed springs had an aver-
`age initial free height of about 10.05". During each compres-
`sion cycle, the springs were compressed and released from a
`height of about 8" to about 5". Each of the sample coils listed
`
`60
`
`65
`
`undesirable materials. As an example, in certain applications,
`sulfur may be an undesirable element in steel alloys. In such
`an example, titanium may be combined with the alloyed steel
`whereby the titanium binds with the sulfur, thereby mitigat-
`ing some of the undesirable effects of sulfur. In certain
`embodiments, titanium may combine with oxygen and assist
`in deoxygenating the wire 102. In other embodiments, the
`Ex.1001IPage12 of 15
`
`

`
`US 8,474,805 B2
`
`7
`wire 102 can be surface-treated, such as by being galvanized
`or coated with a plastic or epoxy.
`FIG. 2 shows schematically a multi-strand coil spring 200
`according to an illustrative embodiment ofthe invention. The
`coil spring 200 employs a m11lti-strand cord 222, which is
`bent to form the coil spring 200. In certain embodiments, least
`two strands or wires are twisted to form the multi-strand cord
`
`222. Each strand may be formed from a wire similar to wire
`102 of coil spring 100 depicted in FIG. 1. However, the
`number of strands employed varies according to the applica-
`tion and the type ofmaterial used to form the strands. In some
`constructions, the cord 222 is formed from braiding or twist-
`ing three or more strands. In one construction, the multi-
`strand cord 222 includes from three to about fifiy twisted or
`braided strands.
`
`The strands may be twisted, woven, clipped or bonded
`together, and any suitable method for forming the multi-
`strand coil spring may be employed without departing from
`the scope ofthe invention. Moreover, the strands may have an
`ovular, circular, hexagonal, square, flattened version of any of
`the preceding or any other s11itable cross-sectional geometry,
`and may be formed into any number of coils. Also, the coils
`themselves may be formed as active or inactive coils, and may
`all have substantially equal coil diameters. Alternatively, the
`coil diameter may vary from coil to coil, and may be arranged,
`for example to have sequentially increasing coil diameters,
`sequentially decreasing coil diameters, or some combination
`of both,
`to form any suitable coil diameter pattern, for
`example, for forming a coil spring having a variable spring
`rate.
`
`The exemplary multi-strand coil spring 200 can be fabri-
`cated by initially providing the individual strands with a heli-
`cal twist prior to the cording operation. The helix of the
`multi-strand spring preferably opposes the helix of the indi-
`vidual strands to counteract a tendency of the strands to
`loosen when the spring is operated, i.e., compressed. Addi-
`tionally, as with conventional springs, a torque is applied to
`the cord during coiling.
`The individual strands may be connected to each other at
`least at the ends of the coil. Since the strands can rub against
`each other over the length ofthe coil, which can cause fretting
`and premature wear, the strands may be coated and/or pre-
`galvanized or otherwise treated. Moreover, the multi-strand
`coil may also be sealed/coated with a sealant, such as an
`epoxy. Generally, the coil spring 200 may include a multi-
`strand coil such as those described with reference to U.S. Pat.
`
`Nos. 6,944,899, 7,047,581, 7,168,117, and U.S. patent appli-
`cation Ser. No. 11/699,184, each of which are incorporated
`herein by reference in their entirety.
`FIG. 3A depicts an encased microalloyed coil spring 300,
`according to an illustrative embodiment ofthe invention. The
`spring coil 300 may have an encasing material 304, such as
`fabric. The encasing material may be, for example, fabric or
`foam. In certain embodiments, the encasing material 304
`includes at least one of polyester and polypropylene. In cer-
`tain embodiments, the encasing material 304 includes fire-
`retardant material. The encasing material may form a pocket
`and may be useful to attach together a row of adjacent spring
`coils. Encased coils may also improve the manufacturing
`process by obviating the need to connect adjacent open coils
`with hog rings or other fasteners.
`In certain embodiments, the coil spring 100 or 200 may
`then be passed to an encasing machine or station to encase the
`springs into encasing 304 such as non-woven, non-allergenic
`fabric. Each sleeve may be ultrasonically sealed by a process
`where the fibers are melted together to form plastic seams,
`which are secure and tear-resistant. The coils 100 or 200 may
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`8
`then be fusion bonded to produce a strong, stable construc-
`tion. The number of coils in each unit may vary, and the types
`of coils and the number of strands and gauge of strands can
`vary from encasement to encasement, and multi-strand coils
`may be employed in combination with single strand coils.
`In certain embodiments, the microalloyed coil springs 100,
`200 or 300 are configured to provide a similar level of firm-
`ness to users with different weights. In such embodiments the
`coil springs may be asymmetrical in shape including portions
`having linear and non-linear spring rates. FIG. 3B depicts an
`encased asymmetrical coil spring 350, according an illustra-
`tive embodiment ofthe invention. The asymmetrical microal-
`loyed spring 350 includes an upper conical or frustoconical
`portion and lower cylindrical portion. Such an arrangement
`allows a user of the mattress to experience non-linear com-
`pression without causing a substantial compression ofthe coil
`springs. Such a coil spring provides for a mattress that is
`sufficiently sofi for lighter users and sufficiently firm for
`heavier users. In certain embodiments, the coil spring 350
`may be similar to the coil springs described in U.S. Pat. No.
`6,931,685 and U.S. patent application Ser. No. 11/978,869,
`each of which are incorporated herein by reference in their
`entirety.
`FIG. 4 depicts a mattress assembly 400 containing a plu-
`rality ofmicroalloyed coil springs 406. The mattress 400 may
`have a bottom layer 402 and one or more top layers ofuphol-
`stery 412 and foam 408. The mattress may also have one or
`more additional layers 410. The mattress 400 comprises at
`least one microalloyed coil spring 406 which may be encased
`in a pocket. The mattress 400 includes sidewalls 404 arranged
`around the periphery of the innerspring core 405. Adjacent
`encased springs may be connected with attachments such as
`glue.
`The bottom layer 402 provides support to the mattress and
`prevents sagging. This layer may include rigid materials such
`as wood, metal, resins, or plastic. The upholstery layer 412
`forms a soft but durable outer surface to the mattress. The
`
`upholstery layer may protect the inner components of the
`mattress against daily wear and tear. It also provides a soft
`sleeping surface for the mattress user. In certain embodi-
`ments, the mattress 400 may have additional layers 410.
`Additional layers 410 may include backing layers, fire-retar-
`dant materials to improve the safety of the mattress, water-
`resistant materials, water-proof materials, allergen-reducing
`material, mite-proof materials, or materials that protect
`against other organisms. Alternatively, an additional layer
`could be a soft material such as foam 408 that improves the
`comfort of the mattress.
`The mattress 400 includes an innerspring assembly having
`at least one microalloyed coil spring 406. The spring 406 may
`be similar to the springs described with reference to FIGS.
`1-3. The innerspring assembly could contain two or more
`different kinds of springs. For example, conventional steel
`springs may be used in one part of the mattress, and the
`microalloyed steel springs may be used in another part ofthe
`mattress. One or more microalloyed springs 406 in the mat-
`tress 400 may be encased in a pocket. This pocket may be
`made of fabric, foam, or other material. One continuous piece
`of encasing material may cover multiple coils, connecting
`them. Adjacent encased coils may alternatively be connected
`by gluing the encasing material together. Open coils, in con-
`trast, may be connected with a hog ring or ot