Case 1:17-cv-00770-JDW-MPT Document 121-2 Filed 11/17/22 Page 1 of 12 PageID #:
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`Rahn Reply
`Declaration
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`Case 1:17-cv-00770-JDW-MPT Document 121-2 Filed 11/17/22 Page 2 of 12 PageID #:
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`WIRTGEN AMERICA, INC.
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`Plaintiff/Counterclaim-Defendant,
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`CATERPILLAR INC.
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`Defendant/Counterclaim-Plaintiff.
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`IN THE UNITED STATES DISTRICT COURT
`FOR THE DISTRICT OF DELAWARE
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`Case No. 1:17-cv-00770-JDW-MPT
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`JURY TRIAL DEMANDED
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`SUPPLEMENTARY DECLARATION OF CHRISTOPHER D. RAHN, PH.D IN
`SUPPORT OF PLAINTIFF/COUNTERCLAIM-DEFENDANT WIRTGEN AMERICA
`INC.’S REPLY CLAIM CONSTRUCTION BRIEF
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`Case 1:17-cv-00770-JDW-MPT Document 121-2 Filed 11/17/22 Page 3 of 12 PageID #:
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`I, Christopher D. Rahn, hereby declare as follows:
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`I.
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`INTRODUCTION
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`1.
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`I have been retained by plaintiff/counterclaim-defendant Wirtgen America, Inc. (“Wirtgen
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`America”) to evaluate U.S. Patent Nos. 7,946,788 (“Ex. G1” or “the ’788 Patent”), 8,511,932 (“the
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`’932 Patent” or “JCCC Ex. H”), and 8,690,474 (“Ex. H” or “the ’474 Patent”) (collectively, the
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`“sensor switching patents”), as well as RE48,268 (“Ex. J” or “the ’268 Patent”) (the “vibration
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`mounting patent”), which I understand are asserted by Wirtgen America in this case. I submit this
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`declaration in support of Wirtgen America’s Reply Claim Construction Brief and as a supplement
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`to my September 1, 2022 declaration.
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`2.
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`I am being compensated for my time at the rate of $770 per hour. My compensation does
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`not depend on the opinions that I have offered or the outcome of this case. All the opinions stated
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`in this declaration are based on my own personal knowledge and professional judgment; if called
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`as a witness during the trial in this matter, I am prepared to testify competently about them.
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`II. MATERIALS CONSIDERED
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`3.
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`In forming my opinions, I reviewed Caterpillar’s Answering Claim Construction Brief
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`dated September 22, 2022, accompanying exhibits Z to AD, and the declaration of Richard W.
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`Klopp, Ph.D. in addition to the references I identified in my September 1, 2022 declaration.
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`1 Exhibits A-O refer to exhibits filed with the Joint Claim Construction Chart for Wirtgen America’s Asserted Patents
`(D.I. 96). Exhibits P-Y were produced by Wirtgen America in connection with Wirtgen America’s Opening Claim
`Construction Brief. For the purpose of uniformity across claim-construction filings, Wirtgen America cites to the
`references listed in the “Table of Cited References and Exhibits” in the Opening Claim Construction Brief, and I,
`Christopher D. Rahn, Ph.D., cite to the same in this Declaration in Support of Wirtgen America’s Reply Claim
`Construction Brief.
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`1
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`III. CLAIM INTERPRETATION (VIBRATION MOUNTING)
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`A. “accommodates a lack of alignment”
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`4.
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`In my opinion the term “accommodates a lack of alignment” in the claims reasonably
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`informs skilled artisans as to the scope of the claims. A skilled artisan would have understood
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`“accommodates a lack of alignment” refers to the misalignment that the claimed articulated
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`coupling permits between connecting shafts of the drive train compared to the misalignment
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`achieved in prior art machines. The background section of the ’268 patent explains that prior art
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`machines required the entire drive train, from the engine to the traction drive pulley, to be mounted
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`to the machine’s frame in a stiff manner so that the drive shafts of all drive train components were
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`coaxial and rigidly supported. Ex. J, 1:34-50. The drive trains of prior art machines included
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`engines that were rigidly mounted on the machine frame and supported other drive train
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`components such as belt drives and their belt pulleys. Ex. J, 1:42-44. The drive trains included “a
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`coaxial, rigidly supported arrangement” of shafts which connected the drive train components. Ex.
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`J, 1:45-50. The coaxial, rigid arrangement “was a basic requirement for the functional performance
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`and long life” of the belt drive. Ex. J, 1:45-50. Supporting the drive train with soft, elastic supports
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`was infeasible. Ex. J, 1:50-56. A skilled artisan would have understood that the drive shafts in
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`these prior art machines were permanently in precise alignment, including during operation.
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`5.
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`Reading the specification, a skilled artisan would have understood that the ’264 patent’s
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`claims require that the drive engine be supported on the machine’s frame using soft, elastic
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`supports with a lower spring stiffness than the supports of other drive train components such as
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`the pump drive and drive pulley. The specification explains that drive train components with
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`different support stiffnesses can move or vibrate differently during operation. The articulated
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`coupling accommodates the dynamic shaft misalignment that arises due to the relative motion
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`between these drive train components.
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`“The different manner of support or attachment of the first and the second groups
`3, 5 of the drive train 8 has the effect that, when in operation, the not depicted output
`shaft of the combustion engine 10 is not permanently in precise alignment with the
`also not depicted input shaft of the pump transfer case 16, with the articulated
`coupling device 20 balancing the dynamic misalignment occurring during
`operation without the flow of power in the drive train 8 being disturbed.
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`Ex. J, 5:17-25; see also Ex. J, 2:21-30, 44-60.
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`6.
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`A skilled artisan would understand that articulated couplings accommodate lack of
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`alignment, overcoming the precise alignment required in prior art machines. The “articulated
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`coupling accommodates a lack of alignment between the output axis of the drive engine and the
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`input axes of the hydraulic pump drive and the drive pulley due to dynamic movement of the first
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`subset relative to the second subset during operation of the construction machine.” See, e.g., Ex.
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`J, Claim 14 (emphasis added). 7:43-49, 9:39-44, 11:37-42. Thus, prior art rigid couplings would
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`not accommodate the lack of alignment required in the claims.
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`B. “spring stiffness”
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`7.
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`I disagree with Caterpillar’s expert, Dr. Klopp, that “spring stiffness” should be construed
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`to mean “spring constant” based on what a skilled artisan would have understood from the ’268
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`patent and prosecution history. The term spring constant does not provide a meaningful basis for
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`comparing the stiffnesses of the different types of drive train supports that skilled artisans would
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`have used for the claimed engine or drive train mounts. Defining spring stiffness by a singular
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`spring constant improperly requires that the mounts be elastic, linear, and lossless, limitations that
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`are not required by the claim term. Real mounts do not exhibit the ideal behavior associated with
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`a “spring constant”.
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`8.
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`Skilled artisans would understand the use of mounts made from metal, elastomeric material
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`(e.g., rubber), and other well-known mounting materials that may not have ideal elastic behavior.
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`Elastomeric mounts, for example, display inelastic behaviors such as creep under static loads and
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`viscoelastic damping under dynamic (i.e., vibrational) loading.
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`9.
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`As I pointed out in my Opening Declaration, the claims describe two sets of mounts used
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`to support a construction machine drive train and requires that only one set to behave elastically.
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`For example, claim 14 requires a first set of mounts to attach the drive train to the machine frame
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`“elastically with a lower spring stiffness” than a second set, but only requires that the second set
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`of mounts attach the drive train to the machine frame “with a higher spring stiffness or in a rigid
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`manner.” A skilled artisan would have understood from the claim language that spring stiffness
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`does not necessarily require elastic behavior, otherwise there would be no need for the claim to
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`specify that the first set of mounts is attached elastically. Therefore, I disagree with Dr. Klopp’s
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`assertion that the term “spring stiffness” should be construed to require “…that the structures
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`behave elastically.” The term “spring stiffness” should not be construed to exclude structures that
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`are not elastic.
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`10.
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`The ’268 patent’s specification supports the conclusion that spring stiffness is not limited
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`to mounts that behave elastically. The specification references the spring stiffness of transmission
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`mounts it does not describe as elastic. For example, in Figs. 1-4 the specification identifies mount
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`structures “elastic spring/damping elements 22”, which a skilled artisan would have understood
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`behave elastically. In contrast, the “spring/damping elements 24 showing high spring stiffness” do
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`not include the descriptor “elastic” so they can include elements that are not elastic that exhibit
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`spring stiffness. See, e.g., Ex. J, 57-16. I understand that the figures of a patent may only provide
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`a schematic representation of various examples described in the specification. I note, however, that
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`Figs 1-4 (Fig. 4 copied below) depict mount structures 22 that look like springs. Mount structure
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`24, on the other hand, looks like a block. Nothing in the figure suggests these two structures behave
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`similarly. Accordingly, I disagree with Dr. Klopp that “spring stiffness” must be construed to
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`require the elastic behavior. The term “spring stiffness” refers to “resistance to deformation”.
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`11.
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`The term “resistance to deformation” applies to materials and the mounts such as drive
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`train supports or attachments, that are made from these materials. As discussed above, engine and
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`transmission mounts are routinely made from materials like elastomers and rubber. To isolate
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`vibrations, these mounts include elastomeric structural elements that bear at least a portion of the
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`load applied to the mount. U.S. Patent No. 5,809,985 to Kingsley et al., for example, describes
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`rubber mounting blocks that isolate engine vibrations from a concrete saw frame. The portion of
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`the load borne by the elastomeric structural element deforms the material. Accordingly, the
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`material and the mount itself resists this deformation.
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`12.
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`I disagree with Dr. Klopp that elastic mounts that support the ’268 patent’s engine on the
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`machine frame “elastically with low spring stiffness that damps the vibrations from the drive
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`engine” must be linearly elastic and have a spring constant. As I noted previously in paragraphs
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`76-77 of my September 22 declaration (citing the Hibbeler and Callister references), natural rubber
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`is one example of material (an elastomer) where stress and strain are not linearly related. As I also
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`explained in paragraph 75 of my September 22 declaration, other materials, such as steel, exhibit
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`non-linear elastic behavior beyond their proportional limits but before the material’s elastic limit.
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`See Opening Decl. ¶¶75-77; Ex. X, 86. When these materials are formed into mounts and other
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`support structures, the structure incorporates the behavior of the constituent material. Thus, mounts
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`that are made from materials exhibiting non-linear behavior also exhibit non-linear behavior.
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`13.
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`According to Caterpillar, the spring constant is “the ratio of the force affecting the spring
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`to the displacement caused by it.” Caterpillar’s Ans. Brief at 12. This incorrectly limits the claim
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`to devices with a singular ratio that does not vary with the size of the applied force, requiring that
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`the force/displacement curve be a straight line with a constant slope. This also incorrectly limits
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`the claim to devices that operate a constant temperature and in static loading. Elastomers become
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`stiffer at lower temperatures and softer at higher temperatures, so there is not one spring constant
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`for all operating conditions. Skilled artisans have approximated the static behavior of some metal
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`structures over infinitesimally small displacements using a single spring constant. But, as Dr.
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`Klopp points out in his declaration, even a metal spring “…exhibits a nonlinear force-displacement
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`response by virtue of variably spaced spring coils that collapse together.” (See also the “non-linear
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`load-deflection curve” in Fig. 4 of Klopp’s declaration). Elastomeric mounts do not have a single
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`spring constant that approximates or usefully represents the behavior of the mount under the range
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`of operating conditions a skilled artisan would have expected in the ’268 patent’s construction
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`machine.
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`14.
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`Spring stiffness means “resistance to deformation,” as Wirtgen proposes. Resistance to
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`deformation is measured by the force required to displace the mount. Unlike spring constant,
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`resistance to deformation does not assume a single constant value for spring stiffness when
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`comparing different mounts made of different materials under different conditions. The claim
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`requires that a skilled artisan can determine that the second spring stiffness associated with the
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`drive train support structure is higher than the first spring stiffness associated with the engine
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`support structure. For example, a skilled artisan can make this comparison by applying the same
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`force to both support structures and measuring their respective displacements under the same
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`conditions. To meet the claim requirements, the measured displacement of the second support
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`structure should be smaller than the measured displacement of the first support structure, indicating
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`that the spring stiffness of the second support structure is higher than the spring stiffness of the
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`first support structure.
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`15.
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`Caterpillar’s references and arguments demonstrate the problems of defining spring
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`stiffness as spring constant. Spring constant assumes linear (a straight line relationship between
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`force and displacement of a mount or support) and ideal elastic (completely reversible) behavior.
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`A linear relationship between force and displacement can only be obtained for infinitesimally small
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`(essentially zero) and static displacements. Skilled artisans would understand, however, that
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`construction machines have nonzero and dynamic vibrations. If the engine displacements were
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`essentially zero, then the engine would not be vibrating and there would be no need to reduce
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`transmission from the drive engine to the machine frame.
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`16.
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`For example, the marketing brochure of the James Spring & Wire Company cited by
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`Caterpillar provides a simplified description directed to customers regarding the approximate
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`behavior of its typical wire spring products, not of conventional elastomeric drive train mounts.
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`Ex. Z. The brochure assumes ideal material behavior or “the linear elastic deformation of
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`materials,” to approximate the behavior of its metal springs “using a spring constant.” Ex. Z, 1.
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`Ideal, linear elastic behavior is both inaccurate and unrepresentative of real supports.
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`EP1153973A1 cited by Dr. Klopp, for example, describes rubber supports and measures multiple
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`different “spring constants” for the same material tested under static and dynamic loading
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`conditions. First, the “static spring constant” was calculated using arbitrary compressive strains of
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`1.25 mm and 3.75 mm. Using 1 mm and 4 mm compressive strains instead would have resulted in
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`a different “static spring constant”. There is no single “static spring constant” that is representative
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`of the elastomer’s stiffness. Second, the “dynamic spring constant” was calculated by compressing
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`the material by an axial distance of 2.5 mm and introducing a dynamic load of 0.05 mm amplitude
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`at 100 Hz. Ex. AB, ¶¶65-67. Again, if any of these three numbers (2.5 mm, 0.05 mm, or 100 Hz)
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`was changed, a different “dynamic spring constant” would have been generated. Rahn Decl. ¶¶76-
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`77. The other reference Caterpillar cites relating to elastomeric supports (U.S. Patent No.
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`7,357,379) also discusses “dynamic spring constants” (Col. 4, Ln. 24).
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`17.
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`Construing “spring stiffness” as “resistance to deformation” avoids the confusion
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`associated with determining a singular spring constant. Again, the claim only requires a skilled
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`artisan to compare the stiffnesses of two supports so they would simply apply the same force to
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`both supports under the same conditions and measure their displacements. The support with the
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`smaller displacement has the higher stiffness.
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`8
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`18.
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`Caterpillar argues that construing “spring stiffness” as “resistance to deformation” would
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`not assist the finder of fact in understanding the scope of the ’268 patent’s claims because it would
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`capture embodiments that do not behave elastically. These embodiments, they allege, are neither
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`taught nor contemplated by the patent. But the claims do not require all claimed supports to behave
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`elastically. The claims are explicit and recite “elastically” when it is required. Thus, they only
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`require supporting the drive engine or first subset “elastically with a lower spring stiffness.” The
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`second subset is supported with “a higher spring stiffness” or “in a rigid manner” and need not be
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`supported elastically. Indeed, construing spring stiffness to require elastic behavior, as Caterpillar
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`suggests, is incorrect because it improperly makes the word “elastically” recited in the claim
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`superfluous.
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`19.
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`I disagree with Dr. Klopp’s assertion that “resistance to deformation” cannot be used to
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`describe structures but “merely the material the structures are made from.” As I have explained
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`previously, the “stiffness of an attachment depends on the structure of the mounting and on the
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`resistance to deformation of the materials used in the mount’s construction”. Rahn Decl., ¶74. But
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`resistance to deformation also describes the resulting behavior of the support or mount formed
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`using the material. I have also explained that “the stiffness or rigidity of an attachment between
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`two machine components is the extent to which the attachment resists deformation in response to
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`an applied force. Rahn Decl., ¶74. Considering the knowledge in the art, in my opinion a skilled
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`artisan would have understood “spring stiffness” to mean “resistance to deformation” of the
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`claimed support.
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` hereby declare that all statements made herein are made of my own knowledge and are true and
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` I
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`that all statements made on information and belief are believed to be true; and further that these
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`statements were made with the knowledge that willful false statements and the like so made are
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`punishable by fine or imprisonment, or both, under Section 1001 of Title 18 of the United States
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`Code.
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`Executed on this ____ day of ________
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`_______________________
`Christopher D. Rahn, Ph.D.
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`, 2022.
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