Thermal Dynamics v . TATRAS CV-04-152-PB 12/09/04

UNITED STATES DISTRICT COURT FOR THE DISTRICT OF NEW HAMPSHIRE

Thermal Dynamics Corporation

v. Civil N o . 04-152-PB Opinion N o .

TATRAS, Inc.

MEMORANDUM AND ORDER

Thermal Dynamics Corporation claims that TATRAS, Inc. is

currently selling ridged electrodes that infringe U.S. Patent N o .

4,782,210 (“‘210 Patent”). In this Memorandum and Order, I

construe several disputed terms in plaintiff’s patent.

I . BACKGROUND

The ‘210 Patent claims a novel electrode design that was

intended for use in a plasma-arc torch. The first part of this

section describes what a plasma-arc torch is and how it operates.

The second part describes both the patented technology and the

specific claim that is at issue in this dispute. The third and final part describes the electrode design adopted by defendant:

a design plaintiff alleges infringes its patent.

A. The Plasma-arc Torch

A plasma-arc torch cuts and welds hard metal. It operates

by directing plasma1 onto a workpiece at varying temperatures.

The plasma produced by the torch is created by bringing a gas, in

its normal state, into contact with an electric current. The

electric current ionizes and superheats the gas, which is then

forced through a small orifice at the tip of the torch and onto a

workpiece. A superheated stream of plasma can approach

temperatures of 20,000ºC.

The electrical current that is used to heat the gas is

called a “pilot arc” and is generated by an electrode inside the

torch. This process is initiated when the electrode assumes a

negative charge. In this state, the electrode becomes a

“cathode.” The torch tip, in response, assumes a positive

charge, becoming an “anode.” When the torch is operating

properly, electrons jump the gap between the electrode (cathode)

and the torch tip (anode), creating an electrical current. When

1 Plasma is an ionized, superheated gas sometimes described as the fourth state of matter.

-2- gas travels through the current, it becomes plasma.

Before plaintiff developed the technology described in the

‘210 patent, the electrodes used in Plasma-arc torches had smooth

sides and required between 5 and 12 kilovolts (“KVs”) of starting

power to generate the “pilot arc.” The use of such a high

voltage was problematic both because it was a challenge to

consistently produce the required voltage when the plasma-arc

torch was first developed and because the required voltage caused

the electrodes to rapidly decay. The ‘210 patent attempted to

address these problems through an electrode design that allows a

lower voltage to be used in producing the plasma.

B. Plaintiff’s Electrode Design

The ‘210 patent claims an electrode with ridges that

facilitate pilot arching at lower energy levels of between 3-6

KV. The patent includes ten separate claims. Claim 1 is the

patent’s sole independent claim. Claims 2-10 are all dependent

claims. The parties agree that their dispute is limited to the

construction of portions of claim 1 . Those portions claim the

following:

In a plasma-arc system comprising spaced, electrically conductive electrode means defining an arc chamber therebetween, pilot arc voltage supplying means

-3- connected to said electrode means, and means for supplying a flow of plasma forming gas through said arc chamber, the improvement which comprises:

said electrode means including at least one electrode having at least one ridge being located substantially in said arc chamber and extending along said electrode so as to provide a path for arcing, thereby producing a longer wearing electrode.

In addition to its multiple claims, the ‘210 patent also

contains a lengthy description of the invention’s preferred

embodiment. This embodiment illustrates the electrode’s

preferred shape and identifies its location inside the torch.

See ‘210 Patent, Figure 1 . The electrode is depicted as a

cylinder with a domed top. The cylinder is situated in a

chamber, leaving space between the top portion of the electrode

and the body of the torch. Gas flows through the chamber and

over the tip of the electrode. The tip of the electrode is

situated directly behind the torch tip. The torch tip contains

an orifice through which plasma is released. The ridges that

comprise the invention are on the cylindrical side surface of the

electrode and have a lengthwise orientation.

C. Defendant’s Electrode Design

Defendant produces and sells its own electrode. Like the

plaintiffs’ electrode, defendant’s technology is intended for use

-4- in a plasma-arc torch. Additionally, like the preferred

embodiment described in Patent ‘210, defendant’s electrode has

ridges on the surface of a cylindrical-sided electrode. These

ridges, however, radiate from the center point on the electrode

tip and toward the back portion of the electrode but stop at the

point where the domed top of the electrode reaches its

cylindrical sides.

Whether this design infringes plaintiff’s patent will depend

in large part upon how I construe plaintiff’s patent claims. It

is to this task that I now turn.

II. STANDARD OF REVIEW

Claim construction presents a question of law for the court

to resolve. Markman v . Westview Instruments, Inc.,

7 0 ,

372 (1996); Liquid Dynamics Corp. v . Vaughan Co.,

(Fed. Cir. 2004). The starting point is the language of the

claim itself.

“There is a ‘heavy presumption’ that the

terms used in claims ‘mean what they say and have the ordinary

meaning that would be attributed to those words by persons

skilled in the relevant art.’” Superguide Corp. v . DirecTv

Enters., Inc.,

7 0 , 874 (Fed. Cir. 2004) (quoting Tex.

-5- Digital Sys., Inc. v . Telegenix, Inc.,

(Fed.

Cir. 2002). Dictionary definitions are “often useful” in

construing disputed patent terms. Id. at 875. Once a range of

possible meanings has been identified through the use of

dictionary definitions, the context in which a disputed term is

used in the claims and the specification must be carefully

scrutinized to determine the preferred interpretation. See Int’l

Rectifier Corp. v . IXYS Corp.,

(Fed. Cir.

2004). While the specification must always be considered in this

process, claim terms ordinarily are not limited to the

embodiments disclosed in the specification. See Amgen Inc. v .

Hoechst Marion Roussel, Inc.,

(Fed. Cir.

2003). Extrinsic evidence may also prove helpful but such

evidence may not be used to alter the meaning of a claim term

whose definition can be discerned from intrinsic evidence. C.R.

Bard, Inc. v . United States Surgical Corp.,

5 8 , 861

(Fed. Cir. 2004).

Although each claim in a patent is an independent invention,

dependant claims can aid in interpreting the scope of the claims

upon which they depend. Laitram Corp. v . NEC Corp.,

(Fed. Cir. 1995). Under the doctrine of claim

-6- differentiation, where claims in the same patent use different

terms, those differences are presumed to reflect a difference in

the scope of the claims. Forest Laboratories, Inc. v . Abbot

Laboratories,

, 1310 (Fed. Cir. 2001); see also

Ecolab Inc. v . Paraclipse, Inc.,

(Fed.

Cir. 2002) (stating that under the doctrine of claim

differentiation “each claim in a patent is presumptively

different in scope”); Liebel-Flarsheim C o . v . Medrad, Inc.,

9 8 , 910 (Fed. Cir. 2004) (holding that the “presence of a

dependent claim that adds a particular limitation raises a

presumption that the limitation in question is not found in the

independent claim.”).

A court must depart from this methodology in two

circumstances. First, it must do so if the patentee has acted as

its own lexicographer by clearly defining the term in the

specification. In this situation, the court must adopt the

meaning selected by the patentee. See Inverness Med. Switz. GmbH

v . Princeton Biomeditech Corp.,

(Fed. Cir.

2002). Second, it must do so if the patentee clearly surrendered

an interpretation during the prosecution of the patent. See

Superguide Corp., 358 F.3d at 875.

-7- I apply these interpretive standards in construing the ‘210

patent.

III. CLAIM CONSTRUCTION

The parties dispute the meaning of one term and two phrases

in claim 1 . They first disagree as to the meaning of the term

“arc chamber.” They next dispute the meaning of the phrase

“extending along said electrode so as to provide a path for

arcing.” Finally, they offer different interpretations of the

phrase “so as to provide a path for arcing, thereby producing a

longer wearing electrode.”

1. “Arc Chamber”

The parties agree that the patentees acted as their own

lexicographer by defining the term “arc chamber” as the area

between “a pair of spaced-apart electrodes . . . in which

electric arcs are to be formed.” ‘210 patent col. 2 , 1 1 . 59-61.

Plaintiff contends that this definition does not require

elaboration. Defendant, by contrast, argues that the

specification further limits the term to the area between the

cylindrical side surface of one electrode and the surface of

-8- another electrode.

Defendant’s argument fails because it is based on the flawed

premise that the ‘210 patent only covers plasma-arc systems that

use cylindrical electrodes. This premise is plainly wrong.

Claim 1 does not limit the shape that an electrode must take.

Indeed, dependant claim 2 claims “the invention of claim 1

wherein said electrode is of generally rod shape so that the

surface is cylindrical.” ‘210 patent, col. 6, l l . 57-59. In

cases like this, where a dependant claim contains a limitation

that is not expressed in an independent claim, a presumption

exists that the independent claim is not subject to the

limitation described in the dependant claim. See Liebel-

Flarsheim Co., 358 F.3d at 910. Defendant has failed to identify

sufficient evidence to overcome this presumption. Thus, I reject

its argument that the patentee’s definition of arc chamber should

be further limited to the area that lies between the cylindrical

side surface of one electrode and the surface of another

electrode.

B. “Extending Along said Electrode so as to Provide a Path for Arcing”

Claim 1 also states that a ‘210 electrode must have at least

-9- one ridge “extending along said electrode so as to provide a path

for arcing.” ‘210 patent col. 6, 1 1 . 53-54. Defendant proposes

alternative contextual meanings for the term “along.” First, it

argues that dictionary definitions and the figures that

illustrate the invention’s preferred embodiment demonstrate that

“along” means “lengthwise over the longest side surface.”

Somewhat less restrictively, it contends that the patent’s

prosecution history demonstrates that “along” means “over the

side surface.” I examine each argument in turn.

Neither party argues that “along” has a specialized meaning.

Thus, general use dictionaries serve as a useful starting point

for analysis. One such dictionary defines “along” as (1) ‘[b]y

the length; in a line with the length; lengthwise” and (2) “by

the length o f , as distinguished from across.” WEBSTER’S REVISED

UNABRIDGED DICTIONARY (1996). In another, “along” is defined as (1)

“Over the length of” and (2) “On a line or course parallel and

close t o ; continuously beside.” THE AMERICAN HERITAGE DICTIONARY OF THE

ENGLISH LANGUAGE (4th ed. 2000). A third defines “along” as (1)

“through, o n , beside, over, or parallel to the length or

direction o f , from one end to the other of” and (4) “by the

length; lengthwise.” THE RANDOM HOUSE DICTIONARY OF THE ENGLISH LANGUAGE

-10- (2d ed. 1987). In still a fourth, “along” is defined as “in a

line with the length, parallel to the longest dimension or course

(of something understood) . . . .” THE COMPACT EDITION OF THE OXFORD

ENGLISH DICTIONARY (1971). Neither party disputes the validity of

these definitions. Rather, they disagree first over which

definition to invoke, and next over how that definition should

apply in this case.

Although all of the above-cited dictionaries recognize that

“along” generally connotes a lengthwise orientation, the

definitions do not support defendant’s more restrictive

interpretation that a ridge extends along an electrode only to

the extent that it extends lengthwise over the electrode’s

longest surface. An electrode may have many surfaces of varying

lengths that together comprise an electrode that is longer than

it is wide. In such cases, a ridge that extends lengthwise in a

line over the electrode’s entire surface from one end to the

other will extend over multiple surfaces. Some of these surfaces

may be parallel to the electrode’s longest surface and others may

not. Nevertheless, each segment of such a ridge has a lengthwise

orientation with respect to the electrode as a whole regardless

of whether the segment is on or parallel to the electrode’s

-11- longest surface. The dictionaries cited by the defendant in no

way foreclose such an interpretation because they do not require

that the lengthwise orientation must be with respect to an

object’s longest surface rather than the object as a whole.

To further support its position, defendant points to figures

depicting the invention’s preferred embodiment. Although

defendant correctly claims that these figures depict cylindrical

electrodes that have ridges only on their cylindrical side

surfaces, such figures cannot be used to read into the claim a

limitation that it does not contain. See Fuji Photo Film Col,

Ltd. v . International Trade Comm’n,

(Fed.

Cir. 2004). Claim 1 is quite clear in stating that the ridges

that comprise the invention must extend along the electrode

rather than along the electrode’s longest side surface. This

usage leaves no room for defendant’s narrower interpretation.

Defendant alternatively argues that the patent’s prosecution

history demonstrates that along means “extending over the side

surface.” This argument is based on the history of the amendment

to the original application that added the phrase “extending

along said electrode” to what ultimately became claim 1 . The

original application included a claim 1 (“original claim 1 ” ) ,

-12- which was ultimately abandoned, and a claim 10 (“original claim

1 0 ” ) , which ultimately became what is now claim 1 . Original

claim 1 provided in pertinent part for “relief means on said side

surface [of the electrode] extending over a portion of said side

surface intermediate said ends so as to provide a path for arcing

. . . .” Original claim 10 initially provided in pertinent part

for an “electrode having at least one ridge formed thereon, said

ridge being located substantially in said arc chamber.” The

examiner rejected both claims based in part on Patent N o .

3,296,410 (the “Hedger Patent”), which describes an “induction

plasma generator that has as one element an electrode with a

barbed projection at one end. In response, the applicants

explained that their claims differed from the Hedger Patent

because they claimed a ridge which, unlike the barb claimed in

the Hedger Patent, provided a “definition of length” and a “path

to direct the arc.” They went on to state that

Since independent claim 1 already recites that the relief means on the side surface is “extending over a portion of said side surface intermediate said ends so as to provide a path for arcing between the electrode . . .” (emphasis added), it is believed that this amended claim defines over the Hedger reference. By this

-13- amendment, dependent claim 10 2 has been amended to recite that the ridge is “extending along said electrode means.”

Pl.’s Response to Oct. 1 6 , 1987 P.T.O. Official Action at 3 .

Defendant argues that this passage demonstrates that the patentee

incorporated original claim 1’s side surface limitation into

original claim 10 when it amended that claim.

I am unpersuaded by the defendant’s argument. The Federal

Circuit has repeatedly warned district courts that “it is

inappropriate to limit a broad definition of a claim term based

on prosecution history that is itself ambiguous.” Mars Inc. v .

H.J. Herz C o . L.P,

(Fed. Cir. 2004);

Inverness Med. Switz. GmbH v . Warner,

. The

prosecution history cited by the defendant does not come close to

providing unambiguous support for its position. I f , as defendant

claims, the applicants intended original claim 10 to include

original claim 1’s side surface limitation, one would expect that

2 Although this reference refers to original claim 10 as a dependant claim, all other references to the claim in the prosecution history refer to the claim as an independent claim. Moreover, the claim does not appear to be a dependant claim because it does not contain, as it must, a “reference to a claim previously set forth.”

. Accordingly, I assume for purposes of analysis that original claim 10 was intended to be an independent claim.

-14- the applicants would have explicitly included the side surface

limitation in the amendment to original claim 1 0 . Moreover,

although the applicants’ intentions are not clear, a fair reading

of the above-cited passage suggests that they most likely

intended the amendment merely to emphasize that their invention,

unlike the Hedger Patent, taught a ridge that had a “definition

of length” and therefore provided a path for arcing. In short,

the evidence relied on by defendants is too weak to justify a

reading of “along” that is contrary to its customary meaning.3

Accordingly, I decline to adopt either of defendant’s proposed

interpretations of “along.”

C. “So as to Provide a Path For Arcing Thereby Producing a Longer Wearing Electrode

Two additional questions remain regarding the proper

interpretation of claim 1 . Both concern the phrase “so as to

3 Plaintiff asserts that “along” is synonymous with o n . Thus, from its perspective, the orientation of the ridges is irrelevant. I decline to adopt this proposed construction because I am not satisfied that I must do so to resolve this case. I lack the power to give advisory opinions concerning the meaning that patent terms may have in cases that are not before m e . Accordingly, until it becomes clear that I must either adopt or reject plaintiff’s proposed interpretation to resolve this case, I decline to do s o . It is sufficient at the present time to merely state that defendant’s proposed interpretations are unjustifiably narrow.

-15- provide a path for arcing, thereby producing a longer wearing

electrode.” Plaintiff asks me to construe the phrase “thereby

producing a longer wearing electrode.” Defendant asks me to

construe the phrase “so as to provide a path for arcing.”

Because I conclude that the phrase “thereby producing a longer

wearing electrode” merely describes an expected result of the

invention claimed in the ‘210 patent, I hold that it does not

limit the patent’s scope. On the other hand, because the

plaintiff concedes that the phrase “so as to provide a path for

arcing” is an explicit claim limitation, I accept that conclusion

without undertaking further analysis.

1 . “Thereby producing a longer wearing electrode”

Claim 1 states that ridges shall be formed along an

electrode “thereby producing a longer wearing electrode.”

Plaintiff argues that this phrase does not further limit what is

otherwise claimed under the patent. I agree.

In Texas Instruments v . United States Int’l Trade Comm’n,

the Federal Circuit held that “a ‘whereby’ clause that merely

states the result of a limitation in the claim adds nothing to

the patentability or substance of the claim.” 988 F.2d at 1172

(citing Israel v . Cresswell,

(C.C.P.A. 1948)).

-16- That is because stating the result of an invention in a patent

does not affect its patentability. Israel,

.

In this case, the “thereby” clause, like the “whereby”

clauses in Texas Instruments and Israel, merely states one result

of the ‘210 patent: a longer wearing electrode. I therefore

conclude that the phrase does not limit plaintiff’s patent claims

in any way.

2. Construing “so as to provide a path for arcing”

Claim 1 also states that ridges shall be carved into its

electrode “so as to provide a path for arcing.” Defendant argues

that this phrase should be construed as a functional limitation

on the scope of the subject matter protected by plaintiff’s

patent. Plaintiff concedes this point. I therefore accept this

construction.

IV. CONCLUSION

For the reasons set forth in this Memorandum and Order, I :

(1) adopt the definition of “arc chamber” that is provided in the

specification; (2) reject defendant’s proposed contextual

interpretations of “along”; (3) determine that the phrase

-17- “thereby producing a longer wearing electrode” does not operate

as a claim limitation; and (4) agree that the phrase “so as to

provide a path for arcing” serves as a functional limitation on

the scope of claims.

SO ORDERED.

Paul Barbadoro United States District Judge

December 9, 2004

cc: Peter Cowan, Esq. Thomas Donovan, Esq. Douglas Dozeman, Esq. Stephen Garlock, Esq. Paul Maddock, Esq. Janet Ramsey, Esq. Jacob S . Wharton, Esq.

-18-