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Lift-U, A Division of Hogan Mfg., Inc., A California Corporation v. Ricon Corp.

UNITED STATES DISTRICT COURT NORTHERN DISTRICT OF CALIFORNIA SAN JOSE DIVISION


October 28, 2011

LIFT-U, A DIVISION OF HOGAN MFG., INC., A CALIFORNIA CORPORATION,
PLAINTIFF,
v.
RICON CORP., A CALIFORNIA CORPORATION, AND WESTINGHOUSE AIR BRAKE TECHNOLOGIES CORPORATION DBA VAPOR BUS INTERNATIONAL, A DELAWARE CORPORATION,
DEFENDANTS.

The opinion of the court was delivered by: Lucy H. Koh United States District Judge

ORDER CONSTRUING DISPUTED CLAIM TERMS

Plaintiff Lift-U, Inc. ("Lift-U") filed suit against Defendants Ricon Corp. and Westinghouse Air Brake Technologies ("Defendants"), alleging infringement of four patents. The parties now 19 seek construction of ten disputed terms used in the claims of the patents. The Court held a tutorial 20 on September 19, 2011, and a claim construction hearing on September 23, 2011. The Court has 21 reviewed the claims, specifications, and other relevant evidence, and considered the briefing and 22 arguments of the parties. The Court now construes the terms at issue. 23

I.Background

Lift-U designs, develops, manufactures and sells, among other things, fold-out ramps that 25 facilitate handicapped access to public buses. One of Lift-U's products, the "Fold Out Plus," 26 generally lies stowed against the bus floor and is flipped outward through the bus doorway to 27 deploy, similar to a flip-top cellular phone. Such ramps are very stable when stowed or deployed, 28 because gravity holds the flippable portion of the ramp in place. When the ramp is flipped between these two positions, gravity first pulls the ramp towards its starting position, making the flipping 2 hard to start. Midway through the flip, the ramp becomes momentarily balanced, before tipping 3 past its center of gravity and being pulled towards its final, post-flip position. 4

5 force that pushes against gravity. See '433 col. 1:40-53; 2:7-10; 10:15-47; 12:65-13:8. The 6 counterbalance force is provided by a spring or springs. These springs are rigged so that when the 7 ramp is vertical, balanced at its center of gravity, they do not push the ramp in either direction. Id. 8

The invention at issue makes flipping the ramp easier, by providing a "counterbalance"

In contrast, as the ramp tips towards a horizontal position -- stowed or deployed -- the springs 9 become compressed and push back against the force of gravity. Id.

7,533,434 ("the '434 patent") (collectively, "patents-in-suit"). These patents share a common 14 specification. This specification describes an embodiment in which each spring is held between 15 two spring fittings with a rigid rod extending through the spring's center (forming a "spring 16 assembly"). See '433 Patent col. 11:16-54.Each end of the rigid rod is attached to one end of a 17 drive chain. See id. col. 11:16-22. Drive chain segments and the spring assemblies are linked in a 18 series to form an "endless loop," and the ramp is attached to this loop, so that movement of the 19 ramp moves the loop. See id. col. 11:11-15; 12:23-41. A rigid paddle structure sticks into the path 20 of the endless loop. See id. col. 12:1-4. The drive chain slides through a hole in this structure, but 21 the spring fitting cannot. See id. col. 12:3-10. When the spring fitting catches against this 22 immobile "end stop" (a "restraint"), the spring begins compressing, creating a backwards force 23 away from the end stop. See id. col. 12:41-65. This backwards force pushes against the drive 24 chain and against the forces of gravity pulling the ramp. See id. col. 12:54-65. Because the drive 25 chain is narrow, it does not push against the spring directly, and the force from the spring does not 26 push back directly against the drive chain. Instead, the actual compressing of the spring towards 27 the restraint is done by a wider "cylindrical bushing" (a "biasing element") attached to the drive 28 chain. See id. col. 11:34-46; 12:41-53. Certain claims, including claims 10 and 17 of the '433

The ramp counterbalance invention is claimed in a family of four patents assigned to Lift- U:, a parent, United States Patent No. 7,681,272 ("the '272 patent"), and three continuations, United States Patent Nos. 7,533,432 ("the '432 patent"), 7,533,433 ("the '433 patent"), and Patent, achieve the same effect by permanently fixing one spring end to the restraint (rather than to 2 the spring fitting), while leaving the biasing element free until it moves into contact with the free 3 end of the spring and initiates compression. See id. col. 19:14-32; 20:11-32. 4

Lift-U filed for reexamination of the patents-in-suit, after emergence of a prior art 5 reference, the Wittwer Patent, which raised a substantial new question of patentability. See, e.g., Invalidity Mot., ECF No. , Ex. 11 (Request for Reexamination of the '433 Patent). Each patent 7 was amended during reexamination, and the USPTO issued a Certificate of Reexamination for each 8 patent. See Lift-U Claim Construction Br., Exs. I-L (Ex Parte Reexamination Certificates for the Patents in Suit).

The case is currently before the Court for construction of the following ten terms:

(1) "spring";

(2) "compression spring";

(3) "biasing element";

(4) "biasing assembly";

(5) "endless loop";

(6) "coupler";

(7) "force transmission element";

(8) "line;"

(9) "restraint"; and

(10) "spring fitting."

II.Legal Standard

Claim construction is a question of law to be determined by the Court. Markman v. Westview Instruments, Inc., 52 F.3d 967, 979 (Fed. Cir. 1995) (en banc), aff'd 517 U.S. 370 (1996). 24

"Ultimately, the interpretation to be given a term can only be determined and confirmed with a full 25 understanding of what the inventors actually invented and intended to envelop with the claim."

Phillips v. AWH Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005) (quoting Renishaw PLC v. Marposs 27 Societa' per Azioni, 158 F.3d 1243, 1250 (Fed. Cir. 1998)). Accordingly, a claim should be 28 construed in a manner that "stays true to the claim language and most naturally aligns with the 2 patent's description of the invention." Id. 3

In construing disputed terms, the Court looks first to the claims themselves. "It is a 'bedrock principle' of patent law that 'the claims of a patent define the invention to which the 5 patentee is entitled the right to exclude.'" Id. at 1312 (quoting Innova/Pure Water, Inc. v. Safari 6 Water Filtration Sys., Inc., 381 F.3d 1111, 1115 (Fed. Cir. 2004)). Generally, the words of a claim 7 should be given their "ordinary and customary meaning," which is "the meaning that the term[s] 8 would have to a person of ordinary skill in the art in question at the time of the invention." Id. at 9 1312-13. In some instances, the ordinary meaning to a person of skill in the art is clear, and claim 10 construction may involve "little more than the application of the widely accepted meaning of commonly understood words." Id. at 1314. In many cases, however, the meaning of a term to a person skilled in the art will not be readily apparent, and the Court must look to other sources to 13 determine the meaning of the term. Id.

claim, or by usage of the term in related claims. Id. Importantly, however, "the person of ordinary 16 skill in the art is deemed to read the claim term not only in the context of the particular claim in 17 which the disputed term appears, but in the context of the entire patent, including the 18 specification." Id. at 1313. Accordingly, claims "must be read in view of the specification, of 19 which they are a part." Id. at 1315 (quoting Markman, 52 F.3d at 979). Indeed, the specification is 20 415 F.3d at 1315 (quoting Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996)). At the same time, the Federal Circuit has cautioned against limiting claims to the specific 23 embodiments of the invention. Phillips, 415 F.3d at 1323. A court "should also consider the 24 patent's prosecution history, if it is in evidence." Id. (quoting Markman, 52 F.3d at 980).

26 dictionaries and treatises, to shed light on the claimed technology. Phillips, 415 F.3d at 1317.

However, such evidence is considered "less significant than the intrinsic record" and "less reliable 28 than the patent and its prosecution history in determining how to read claim terms." Id. at 1317-18

The meaning of a term may be illuminated by the context in which it is used in an asserted "always highly relevant" and "the single best guide to the meaning of a disputed term." Phillips, 21 In addition to such intrinsic evidence, a court may rely on extrinsic evidence, such as (quotation marks and citation omitted). Ultimately, while extrinsic evidence may be useful in 2 claim construction, "it is unlikely to result in a reliable interpretation of patent claim scope unless 3 considered in the context of the intrinsic evidence." Id. at 1319. 4

III. Discussion

As a preliminary matter, the parties agree that a person of ordinary skill in the art is a 6 mechanical engineer with a four year bachelor's degree in engineering and some design experience 7 relating to ramp and counterbalance mechanisms and knowledge of common machine elements.

A."Spring" and "compression spring"

The terms "spring" and "compression spring" are used throughout the patents-in-suit. The 10 parties propose to define the term spring as follows:

Although the parties identify both "spring" and "compression springs" as disputed terms, 17 their briefing focuses more on the word "spring." Indeed, Defendants' proposed construction of 18 compression spring merely adds the word "compression" to its proposed definition of "spring," 19 apparently conceding that the meaning of the term "compression" is commonly understood by 20 those skilled in the art. 21

Defendants' Proposed Construction Term Lift-U's Proposed Construction "spring" "An elastic element that stores mechanical energy, providing a force in response to a deflection from its rest position" "A helical spring in the form of coiled wire" "compression spring" "A 'spring' as defined above, in which the 'deflection' is a 'decrease in length from its rest position.'" "A helical compression spring in the form of a coiled wire."

Defendants urge the Court to construe "spring" to mean "a helical spring in the form of 22 coiled wire." Lift-U, on the other hand, argues that its proposed definition of "spring" represents 23 the ordinary and customary meaning as understood by mechanical engineers and others skilled in 24 the art. Lift-U argues that Defendants seek a restrictive definition that improperly imports 25 limitations of the preferred embodiment into the claims of the patents-in-suit. At the heart of this 26 dispute is whether the term "spring" includes "gas springs." 27

1. Evidence from the Specification. 2 uniform coil diameter and coil pitch. The specification also discloses other coiled wire spring 3 options, which can alter the relationship between spring compression and force. 4 5 classify these systems as springs. The key language of the specification is found in the '433 Patent: 6 minimize the difference between the force supplied by the springs 104 and the force required to counteract the moment MW as the ramp portion 60 reciprocates between a stowed position and a deployed position. For linear springs, the spring stiffness can be selected such that the linear increase in spring resistance is a best fit of the sinusoidal increase of the moment MF. As a result, the difference between MW and MF is minimized. In other embodiments, non-linear springs are used so that the resistance supplied by the spring increases at a non-linear rate, allowing the spring resistance to match more closely the force required to resist the moment MF as the ramp portion 60 reciprocates between a stowed position and a deployed position.

Non-linear springs are known in the art. For example, a spring formed with a variable coil pitch will exhibit non-linear properties. It should be understood that various known spring configurations providing linear or non-linear reactive force can be included in the counterbalance assembly 100 without departing from the spirit and scope of the present invention. In addition, alternate systems can be used to provide a resistive force, such as pneumatic systems, hydraulic systems, and other systems known in the art.

The diagrams in the specification show only a simple helical coiled wire spring having

The specification briefly discloses that gas systems are possible, but does not appear to

The springs 104 of the counterbalance assembly 100 are preferably selected to

Id. col. 13:9-31 (emphasis added). This passage explains that various spring types can be used to 18 precisely counterbalance the moving ramp as its center of gravity shifts. These spring types appear 19 to be strictly helical wire constructs. The only specific example of a non-linear spring given is one 20 having "variable coil pitch." More significantly, "pneumatic [gas] systems" and other mechanisms 21 for providing resistive force are described as "alternate systems" rather than as springs, and are 22 discussed separately from, and "in addition" to, the "various known spring configurations [that] 23 can be included." 24

Nevertheless, the Court finds that this ambiguous language does not "demonstrate a clear intention to limit the claim scope using words or expressions of manifest exclusion or restriction."

Martek Biosciences Corp. v. Nutrinova, Inc., 579 F.3d 1363, 1381 (Fed. Cir. 2009). Lift-U clearly 27 contemplated that "alternative systems" could be used in its invention and it does not explicitly 28 state that these systems are not springs.

2 the specification can be imported into the claims are inapposite. In Nystrom v. Trex Co., 424 F.3d 3

The Court agrees with Lift-U that Defendants' cited cases suggesting that limitations from 1136 (Fed. Cir. 2005), "board" was construed to refer only to wood products because the 4 specification framed the invention as an improvement to wooden decking technology and because 5 in both the specification and prosecution history, the patentee consistently used the term "board" in 6 reference to wood products. The springs in the '433 specification, by contrast, are framed as 7 improving extendable wheelchair ramp technology by counterbalancing the ramp, and the 8 specification and prosecution history both refer to spring types beyond the scope of Defendants' 9 proposed construction. In ICU Med., Inc. v. Alaris Med. Sys., Inc., 558 F.3d 1368 (Fed. Cir. 2009), 10 the term "spike" was construed to require "a pointed tip for piercing" rather than merely a "projection," because a spike was necessary to accomplish the functional "piercing" limitation implicit in the invention. The function of the '433 Patent's springs is to generate a 13 counterbalancing force as they are compressed between the restraint and the biasing element. This 14 function does not require a helical coiled wire spring, as proposed by the Defendants' construction. 15

In Hologic, Inc. v. SenoRx, Inc., 639 F.3d 1329 (Fed. Cir. 2011), the Federal Circuit reasoned that 16 the term "asymmetrically" has no meaning without an external point of reference, and looked to the 17 specification to identify the necessary reference point only because the claims were silent. In 18 contrast, a person having ordinary skill in the art would not find the term spring meaningless in the 19 absence of an additional "coiled-wire helix" limitation imported from the specification.

Thus, the specification does not support Defendants' proposed construction of "spring" or "compression spring."

24 the prosecution of the '433 Patent, Lift-U distinguished certain prior art references by explaining 25 that: 26

breaking or "float down" features that use hydraulic actuators, electric motors, or gas filled struts to control the descent of the ramp as it is deployed. To the extent that these dynamic breaking or "float down" features do not utilize springs or

2. Evidence from the Prosecution History.

Defendants argue that Lift-U disclaimed gas springs during the prosecution history. During

The following references disclose various ramp configurations that include dynamic provide counterbalancing forces in the manner of the claimed invention, the references are not believed to be material to the patentability of the claimed subject matter. . . .

Allen Decl., Ex. F at USPTO 1217 (emphasis added). Defendants argue that certain of these 4 distinguished prior art references include devices such as "gas filled struts" that would fit Lift-U's 5 definition of a spring. Lift-U's inventor admitted this, at least with respect to one reference (the 6 Gibbs Patent). See Ex. 5, Johnson Dep. 173:14-19. However, Lift-U distinguished the gas strut 7 references on the grounds that the gas struts did not provide a counterbalancing force rather than on 8 the grounds that gas struts are not "springs." See id. at 173:25-174:1. In fact, immediately after 9 stating that the Gibbs Patent discloses a gas spring, Lift-U's inventor stated that this gas spring is 10 not "counterbalancing." Id. Although the parties do not define "counterbalancing," the declaration 11 of the '433 Patent's inventor explains that counterbalancing does not merely slow the ramp's descent, but also helps to lift the ramp back into place. See Johnson Decl. ¶ 4.G. In sum, the plain 13 language of Lift-U's alleged disavowal fails to unambiguously disclaim all gas struts that act as 14 springs. Even assuming there was any disavowal, only non-counterbalancing gas springs would 15 have been disclaimed.

31 of the Weils Patent, as translated from the German by Google Translate. Lift-U objects to the 18 use of Google Translate as hearsay and notes that the PTO did not have access to the translation 19 when reaching its decision. See Lift-U Claim Construction Reply at 7, n.5. The purported 20 translation discloses a possible counterbalancing gas spring. See Defendants' Claim Construction 21

Response, Ex. 8 ("the gas pressure spring 28 is relaxed or tense, with the effort both for lowering 22 and tilting the platform in the high 13 is reduced"). Regardless of the admissibility of this 23 evidence, the existence of a possibly counterbalancing gas spring in one of the distinguished 24 references does not transform Lift-U's statement distinguishing the references on other grounds 25 into "a clear and unmistakable disavowal" of counterbalancing gas springs. Purdue v. Pharma L.P 26

Defendants also argue that the USPTO allowed the '433 Patent to issue over the Suzuki 28 prior art because the '433 spring is not restrained at one end and free at a second end, like the

Of the distinguished set of references discussed above, Defendants also discuss paragraph v. Endo Pharms., Inc., 438 F.3d 1123, 1136 (Fed. Cir. 2006).

Suzuki spring is. Resp. 11 (citing '433 Patent Reasons for Allowance, Ex. 10, at 2). In fact, the 2 very claims at issue in this case involve fixing one end of the spring to the restraint and allowing 3 the other end to move freely. See '433 Patent 19:20-30; 20:15-26 (claims 10 (b)(ii),(iii),

Thus, the prosecution history does not lend any further support to Defendants' construction of the term "spring." 7

8 example, the Johnson Declaration lists all the springs disclosed by prior art references cited during 9 prosecution of the patents-in-suit. See Johnson Decl., Ex. A. During prosecution, Lift-U clearly 10 referred to elements in these references as "springs", and some of these "springs" are not coiled Johnson Decl. ¶ 4.D. These references to other types of springs strongly contradict Defendants' 14 proposed construction, which would limit springs to only coiled wire helices. Although leaf 15 springs and torsion rods do not appear to include "pneumatic systems" or "hydraulic systems," the 16 intrinsic evidence makes clear that Defendants' proposed construction is inaccurately narrow 17 because it excludes torsion rods and leaf springs.

20 compression spring (mechanical or pneumatic)" in an international patent application and that Construction Reply at 6. Although this extrinsic evidence post-dates Lift-U's patent applications 23 by two years, Defendants' engineers' description of compression springs as pneumatic is consistent 24 with Lift-U's inventor's testimony that "pneumatic springs" are alternatively referred to as "gas 25 springs" and can be compressed. Johnson Decl. in Support of Opp'n to Invalidity Mot., ECF No. 26 "pneumatic" contradicts the declaration of Defendants' expert, Mr. Smith, which stated that 28 pneumatic systems do not include springs at all, let alone compression springs. See Invalidity Mot. (b)(ii),(iii)).

Furthermore, some prosecution history supports Lift-U's proposed construction. For wire helices. For example, several references described "torsion rods" as springs, while others refer to "leaf springs." See, e.g., Johnson Decl., Ex. A,at 3 (torsion rod), 8 (leaf spring); see also 13

3. Extrinsic Evidence.

Lift-U notes that Defendants themselves describe the ER-6 ramp as including "a Defendants' internal memos describe the ER-7's "gas struts" as "springs." See Lift-U Claim 22 64 (Johnson Decl.) ¶ 4.E. Defendants' engineers' description of "compression springs" as 27 12 (citing Ex. 3 (Smith Decl.) ¶ 13) ("one of ordinary skill in the art would not understand . . . 2 pneumatic systems as referring to springs at all . . . ."). Therefore, this extrinsic evidence suggests 3 that a person having ordinary skill in the art would generally have viewed "springs" as including 4 "gas springs." Furthermore, Defendants claim that they undertook to design the ER-7 specifically 5 to minimize the risk of infringement litigation over the patents-in-suit. See Ricon Motion for 6

Summary Judgment of Noninfringement at 4. Thus, Defendants' engineers should have been 7 cognizant of the meaning of spring as used in the '433 Patent when they referred to the ER-7's gas 8 springs. 9

The issue before the Court is how a person having ordinary skill in the art would construe "spring" as it is used in the patents-in-suit. See Phillips, 415 F.3d at 1313. How the term is used by Defendants' engineers in relation to their own projects is not independently dispositive.

However, this extrinsic evidence supports the conclusion that the term "spring" in the patents-in-13 suit would be understood by persons having ordinary skill in the art to refer to a variety of 14 structures, including torsion rods, leaf springs, and gas springs. 15

Thus, the Court adopts Lift-U's proposed construction of "spring," "an elastic element that 16 stores mechanical energy, providing a force in response to a deflection from its rest position."

B."Biasing element" and "biasing assembly"

Term Lift-U's Construction Defendants' Construction "biasing element" "An element that transmits or maintains force to or from the spring" "A cylindrical bushing (subject to 35 U.S.C. § 112(6)" "biasing assembly" "A group or assembly of elements that transmits or maintains force to or from a spring" "An assembly of a corresponding inboard and outboard end stops and bushings for compressing a spring disposed there between"

The parties also dispute the meaning of the terms "biasing element" and "biasing 25 assembly." Defendants argue that the term "biasing element" is a functional element governed by 26 35 U.S.C. § 112 ¶ 6 (2006). See Resp. 14. Under § 112 ¶ 6 "[a]n element in a claim for a 27 combination may be expressed as a means or step for performing a specified function without the 28 recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents 2 thereof." Defendants reason that even though the claims never explicitly refer to the "biasing 3 element" as a "means," § 112 ¶ 6 applies because the claim does not convey structure sufficient to 4 perform the claimed function. See Resp. 14 (citing Mas-Hamilton Group v. LaGard, Inc., 156 F.3d 5 1206, 1213-14 (Fed. Cir. 1998)). Thus, Defendants urge the Court to construe "biasing element" to 6 mean "cylindrical bushing," which is the only structure identified in the specification shared by the 7 patents-in-suit that performs the required function. 8 Lift-U argues that Defendants improperly seek to read the limitations of the specification 9 onto the claim terms and that their proposed construction violates the doctrine of claim 10 differentiation by reading a limitation of dependent claims, not found in independent claims, onto the independent claim. Br. at 16, 17 (citing Acumed LLC v. Stryker Corp., 483 F.3d 800, 806 (Fed. Cir. 2007)). 13

14 of biasing elements, i.e., "a group or assembly of elements that transmits or maintains force to or 15 from a spring." Defendants argue that this definition is impermissible and should be limited to the 16 embodiment in the specification, namely "an assembly of a corresponding inboard and outboard 17 end stops and bushings for compressing a spring disposed there between."

19 element" and "biasing assembly."

21 the '433 Patent describes a ramp assembly comprising, among other things, "a biasing element 22 engaged with a second end of the compression spring to urge the second end of the compression 23 spring toward the restraint." Claim 12, which is dependent on Claim 10, adds a limitation not 24 found in the independent claim: "The ramp assembly of claim 10, wherein the biasing element is a 25 bushing . . . ." Id. Under the doctrine of claim differentiation, there is a presumption that 26 limitations added to a term in dependent claims are not to be read into that term as used in 27 independent claims. Acumed, 483 F.3d at 806. Thus, Defendants need to find support beyond the 28

Lift-U urges the Court to construe the closely related term "biasing assembly" as a "group" For the reasons discussed below, the Court adopts Lift-U's construction of "biasing These terms are used throughout the patents-in-suit. For example, independent Claim 10 of language of the dependent claims to rebut this presumption and convince this Court to adopt its 2 proposed construction of "biasing assembly."

4 ones at issue here do not use the term "means," there is a strong presumption that the claims are not 5 a mean-plus-function claim, subject to 35 U.S.C. §112 ¶ 6. Depuy Spine, Inc. v. Medtronic 6

Sofamor Danek, Inc., 469 F.3d 1005, 1023 (Fed. Cir. 2006). This presumption can be overcome by 7 a showing that "a claim limitation is so devoid of structure that the drafter constructively engaged 8 in means-plus-function claiming." Inventio AG v. ThyssenKrupp Elevator Americas Corp., 2011

Defendants' argument based on 35 U.S.C. § 112 fails to persuade. When claims such as the WL 2342744, at *6 (Fed. Cir. June 15, 2011). Certain terms, including "element" rarely convey 10 sufficiently definite structure. Massachusetts Institute of Tech. v. Abacus Software, 462 F.3d 1344, 1354 (Fed. Cir. 2006). However, a court may consider other intrinsic and extrinsic evidence, including the written description, when determining, "if a challenger has rebutted the presumption 13 that a claim limitation that lacks the term 'means' connotes sufficiently definite structure to those 14 of skill in the art." Inventio, 2011 WL 2342744, at *6.

16 information, and thus does not implicate Section 112(6). Depuy Spine, 469 F.3d at 1023. For 17 example, claim 10 of the '433 Patent recites "a biasing element engaged with a second end of the 18 compression spring . . . the biasing element being disengaged from the second end of the 19 compression spring . . ." Because this information describes the positioning and movement of the 20 biasing element relative to other key structural elements of the claimed invention, Section 112(6) is 21 inapplicable. See Greenberg v. Ethicon Endo-Surgery, Inc., 91 F.3d 1580, 1584 (Fed. Cir. 1996) (holding that Section 112(6) was not implicated even though specification referred to "detent 23 element" as a "detent means," because the claims referred to each of the key structural elements of 24 the invention).

Here, the term "biasing element" is not used in the claims without corresponding structural Moreover, the prosecution history undermines Defendants' proposed construction of "biasing element." For example, the Accelerated Examination Support Document filed during 27 prosecution of the '433 Patent identifies a wide variety of prior art biasing elements that are not 28 cylindrical bushings. See Lift-U Claim Construction Br. at 19 (listing various prior art biasing elements identified by the Support Document); Allen Decl., Ex. F (Support Document). For 2 example, the prior art shows that biasing elements can come in the form of a "collar," "a fitting 3 connecting a cable to an extension spring," a "washer," a "key insert," an "arm," a "travelling lug," 4 or a "cross support." Id. 5

Thus, the Court rejects Defendants' proposed construction of biasing element and instead 6 adopts Lift-U's construction, "an element that transmits or maintains force to or from the spring." 7

Although Defendants do not argue that "biasing assembly" is a means-plus-function term, 8 they again propose a construction that is too narrow. Defendants would limit the biasing assembly 9 to include only cylindrical bushings and end-stop restraints. Defendants do not show any basis for 10 limiting biasing assemblies only to cylindrical bushings or only to end-stops, other than the mere 11 fact that these are the specific embodiments of biasing elements and restraints disclosed in the specification. 13

Thus, the Court adopts Lift-U's proposed construction of "biasing assembly," "a group or 14 assembly of elements that transmits or maintains force to or from a spring."

C. "Endless loop"/ "coupler"/ "force transmission element"/ "line"

Term Lift-U's Construction Defendants' Construction "endless loop" "A linear element without ends" "A continuous loop-shaped drive chain formed of an outboard and inboard chain segment coupled to an upper and lower spring assembly" "coupler" "An element that connects" "A drive assembly that includes a chain assembly and a spring assembly" "force transmission element" "An element that transmits or maintains force" "An interconnected chain and spring assembly" "line" "An element having length substantially greater than width" "An interconnected chain and spring assembly"

The disputed terms "endless loop," "coupler," "force transmission element," and "line" are 27 significant in interpreting independent claims 10 and 17 of the '433 Patent, which were amended during reexamination. See Allen Decl., Ex. K (ex parte reexamination certificate for the '433 2 Patent). In particular, amended claim 10(c) reads: 3 a coupler sized and configured to operatively couple the counterbalance to the ramp portion, the coupler comprising a force transmission element defining an endless loop, wherein a first portion of the endless loop is in tension to apply a counterbalancing force produced by the counterbalance to the ramp portion when the ramp portion is located between the neutral position and the stowed position, and a second portion of the endless loop is in tension to apply the counterbalancing force produced by the counterbalance to the ramp portion when the ramp position is located between the neutral position and the deployed position.

Id. col. 2:14-24 (language added during reexamination amendment italicized, disputed claim terms in bold). Amended claim 17 (c) reads:

a coupler disposed between the counterbalance and the ramp portion, the coupler comprising a line defining an endless loop and being operatively coupled to the ramp portion for reciprocating movement between a first direction when the ramp portion moves toward the stowed position and a second direction when the ramp portion moves toward the deployed position.

Id. col. 2:49-55 (language added during reexamination amendment italicized, disputed claim terms in bold).

Lift-U added the "endless loop" limitations to the "coupler" and "line" elements in claims 10 and 17 to distinguish its invention from the Wittwer reference. Wittwer discloses a robotic arm counterbalanced as it moves clockwise when a first "compression spring" is pushed by a first "distribution plate" against a first immobile "compression plate," and counterbalanced as it moves counterclockwise when a second "compression spring" is pushed by a second "distribution plate" against a second immobile "compression plate." See Resp., Ex. 11 at R 2400-2402. The distribution plate is thus similar to a "biasing element," and the compression plate similar to a "restraint," as used in the '433 Patent. Thus, the "endless loop" limitation was added to distinguish the '443 invention from Wittwer.

It is undisputed that in the disclosed preferred embodiment, the "endless loop," the "coupler," the "force transmission element," and the "line" are all roughly embodied by the ring of drive chain segments joined in a series with the spring assemblies.

Defendants argue for constructions that narrowly match this embodiment. Thus, Defendants propose constructions in which the "force transmission element" and "line" are "interconnected chain and spring assembl[ies];" a "coupler" is "a drive assembly that includes a 2 chain assembly and a spring assembly;" and an "endless loop" is "a continuous loop-shaped drive 3 chain" made of linked chains and spring assemblies. 4 structure with longer length than width; a "force transmission element" "transmits or maintains 6 force;" a "coupler" "connects;" and an "endless loop" is a structure that is "linear without ends." 7

In contrast, Lift-U proposes broader constructions. Thus, Lift-U argues that a "line" is a Lift-U argues that the claim differentiation doctrine establishes a presumption against Defendants' proposed construction of these terms requiring that a spring always be part of the 9 endless loop. The Court agrees. As discussed above, under the doctrine of claim differentiation, 10 there is a presumption that the limitations added to a term in dependent claims are not to be read 11 into that term as used in independent claims.

Acumed, 483 F.3d at 806. Here, claim 15 of the '433

Patent, which is dependent on independent claim 10, recites "The ramp assembly of claim 10, 13 wherein the compression spring forms a part of the endless loop." Similarly, claim 19, which is 14 dependent on independent claim 17, recites "The ramp assembly of claim 17, wherein the spring 15 forms a part of the endless loop." The "compression spring" or the "spring" forming a part of the 16 endless loop, is the only limitation added by dependent claims 15 and 19. Under the doctrine of 17 claim differentiation, there is a presumption against reading this limitation onto the terms "endless 18 loop," "coupler," "force transmission element," and "line," as Defendants advocate. Thus, Defendants need to find support beyond the language of the dependent claims to rebut this 20 presumption and convince this Court to adopt its proposed construction of these terms. 21

22 supports Lift-U's proposed construction of these terms. And, although the text of the specification 23 is consistent with Defendants' proposed construction requiring that these disputed terms be limited 24 to chain-spring assemblies, Defendants fail to point to language in the specification that 25 demonstrates a clear intention to so limit the claim scope. 26

"Even where the patent describes only a single embodiment, claims will not be read 27 restrictively unless the patentee has demonstrated a clear intention to limit the claim scope using 28 words or expression of manifest exclusion or restriction." Martek Biosciences Corp. v. Nutrinova, Defendants fail to rebut this presumption. In fact, if anything, the prosecution history Inc., 579 F.3d 1363, 1381 (Fed. Cir. 2009). None of Lift-U's statements during the prosecution 2 history suggests a clear intention to limit the amended claim to the preferred embodiment. To the 3 contrary, the explanations offered to the USPTO on reexamination suggest that the drive chain is 4 simply an example of the disputed terms: the drive chain "forms an endless loop," and the drive 5 chain is a coupler "in that it operatively couples the drive sprocket 84 to the ramp portion 60." See 6 Defendants' Claim Construction Response, Ex. 23 at R 2292.*fn1 7

Thus, the Court adopts Lift-U's proposed constructions of "endless loop," "coupler," "force 8 transmission element," and "line." 9

C."Restraint"

Term Lift-U's Construction Defendants' Construction "restraint" "An element that prevents relative movement" "An end stop that prevents movement in one direction but allows movement in the opposite direction" Defendants again seek to limit these terms to their specific embodiments described in the specification. There is no basis for such limitation in the text of the specification.

Defendants argue that "restraint" requires an "end stop" that stops movement in one 17 direction, but allows movement in the other. See Defendants' Claim Construction Response at 22-18 23. Under such a construction, Defendants' gas spring, which is pinned into place at one end, 19 could not infringe. 20 Lift-U urges the Court to construe "restraint" as "an element that prevents relative 21 movement." It argues that Defendants impermissibly seek to import limitations from the 22 specification onto the claims and that Defendants' proposed construction violates the claim 23 differentiation doctrine. Br. 25. 24

Because the text of the specification does not support Defendants' construction, the Court 25 need not reach Lift-U's other arguments. Even the preferred embodiment does not actually require 26 that an end stop allow movement of the entire spring away from the end stop, as Defendants' 2 proposed construction of "restraint" would require. Indeed, the amount of space, if any, that is 3 allowed between the spring and the end stop is described by the specification as a variable, which 4 can be adjusted to modify how the spring's resistance changes as the ramp moves between the 5 stowed and deployed positions. See '433 Patent col. 14:4-15:9 ("It should be appreciated that each 6 spring assembly 102, 122 may include a dead space 126 at one end, both ends, or neither end."). 7

Thus, even if it were proper for Defendants to import the limitation of the specification into the 8 claim term, the term "restraint" is not limited "to allow movement in the opposite direction" in the 9 specification. 10

Accordingly, the Court adopts Lift-U's proposed construction of "restraint" as "an element that prevents relative movement."

E. "Spring Fitting"

Term Lift-U's Construction Defendants' Construction "Spring Fitting" "An element located at or near one end of a spring, enabling the spring to engage another structure or assembly of structures." "A flanged bushing sizably fitted to alternately move and restrain the end of a compression spring."

As with the other disputed terms, Defendants propose a narrow construction of the term "spring fitting" that limits the term to that described as part of the preferred embodiment in the 18 specification, namely "a flanged bushing." Lift-U argues that this proposed construction 19 impermissibly seeks to import the limitation of the specification in the claims and violates the 20 claim differentiation doctrine. Br. 26.

Defendants do not challenge Lift-U's claim differentiation argument, nor do they point to 22 any language in the specification that demonstrates "a clear intention to limit the claim scope using 23 words or expression of manifest exclusion or restriction." Martek Biosciences Corp. v. Nutrinova, 24 Inc., 579 F.3d 1363, 1381 (Fed. Cir. 2009). Instead, Defendants argue that the spring fitting must 25 be a flanged bushing, pointing only to a single line in the specification which states, "In the 26 illustrated embodiment, the spring fittings 106A-B are shown as flanged bushings," and the fact 27 that the inventors listed this line as supporting the "spring fitting" limitation. See Defendants' 28

Claim Construction Resp. at 25. The quoted sentence does not suggest that this conceptually simple element was limited in the invention to such a narrow range of structures, particularly not 2 when "flanged bushings" are first mentioned only after almost two full pages of discussion 3 involving the spring fittings. See '433 Patent col. 11:26 (first mention of spring fitting 106), col. 4 14:36-37 (mention of the "flanged bushing" embodiment). 5

Accordingly, the Court adopts Lift-U's proposed construction, "an element located at or 6 near one end of a spring, enabling the spring to engage another structure or assembly of structures." 7

IV. Conclusion

For the foregoing reasons, the Court adopts Lift-U's proposed constructions for all of the 9 disputed terms.

IT IS SO ORDERED.


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