               NOTE: Pursuant to Fed. Cir. R. 47.6, this disposition is not
               citable as precedent. It is a public record.

      United States Court of Appeals for the Federal Circuit
                                     05-1056, -1070

                               DANE INDUSTRIES, INC.,

                                                        Plaintiff-Appellant,
                                            v.

                             AMERITEK INDUSTRIES, LLC,

                                                       Defendant-Cross Appellant.

                            _______________________

                            DECIDED: October 26, 2005
                            _______________________


Before RADER, Circuit Judge, ARCHER, Senior Circuit Judge, and SCHALL, Circuit
Judge.

ARCHER, Senior Circuit Judge.

       Dane Industries Inc., (“Dane”) appeals the judgment of the United States District

Court for the District of Minnesota granting Ameritek Industries, LLC’s (“Ameritek”)

motion for summary judgment of noninfringement of U.S. Pat. Nos. 6,220,379 (“the ‘379

patent”) and 5,934,694 (“the ‘694 patent”). Ameritek cross appeals the district court’s

grant of Dane’s motion for partial summary judgment that the ‘379 and ‘694 patents are

not invalid.   The district court erred in its claim construction of the term “a brake

controller” in the ‘379 patent, and therefore we reverse on this issue.         Because

Ameritek’s Golden Retriever device does not contain the “locking means” element

required by the claims of the ‘694 patent, we affirm the grant of summary judgment of

noninfringement as to this patent. Finally, we conclude that the district court correctly
ruled that assignor estoppel prohibits Ameritek from now challenging the validity of the

patents at issue. Accordingly, we affirm-in-part and reverse-in-part and remand for

further proceedings.

                                              I

       The ‘379 and ‘694 patents, owned by Dane, are directed to a vehicle that

retrieves shopping carts. Dane asserts that Ameritek’s Golden Retriever infringes both

patents. Claim 1, representative of the ‘694 patent, recites as follows:

       1. A vehicle for moving at least one wheeled cart, the vehicle comprising:
       a chassis supported by at least two wheels;
              electric drive means supported by the chassis, the drive means
       coupled to the at least two wheels;
              means for generating a drive signal, the drive signal comprising at
       least one target speed;
              a controller coupled to the electric drive means, the controller
       operative to energize the electric drive means to move the vehicle in
       response to the drive signal;
              a front plate mounted on the chassis;
              two jaws protruding from the front plate, wherein said jaws operate
       to engage corresponding vertical frame members of the at least one
       wheeled cart; and
              locking means for locking the at least one wheeled cart to at least
       one of the jaws, wherein the locking means includes a moveable pin
       positionable across an open portion of one of the two jaws.

‘694 patent, col. 7, l. 57 - col. 8, l. 8 (emphasis added). Claim 1 of the ‘379 patent,

representative of the claims at issue in that patent, recites:

       1. A vehicle for moving shopping carts, comprising:
               (a) a chassis supported by at least two wheels;
               (b) a shopping cart coupler mounted to the chassis releasably
       attaching at least one shopping cart or a shopping cart train;
               (c) an electric motor supported by said chassis powering said
       vehicle in response to a drive signal;
               (d) a control panel having a mode selector selecting between a
       plurality of operational modes, including a manual mode and a remote
       mode;




05-1056, -1070                                2
              (e) at least one remote control device generating and transmitting
      an operator signal to operate the vehicle in the remote mode, the operator
      signal including a target speed value;
              (f) a manual control device generating and transmitting an operator
      signal and a stop signal to operate the vehicle in the manual mode;
              (g) a receiver on the vehicle communicating with the remote control
      device to operate the vehicle in the remote mode;
              (h) a controller on the vehicle controlling vehicle movement in
      response to the operator signal, said controller comprising:
              i. a signal receiver connected to the receiver, the signal receiver
      receiving the operator signal;
              ii. a motor switching circuit generating a motor interface signal in
      response to the operator signal;
              iii. a motor interface circuit receiving the motor interface signal from
      the motor switching circuit and generating a drive signal to power the
      motor;
              iv. a speed sensing circuit generating a present speed signal; and
              v. a speed regulating circuit coupled to the motor interface circuit,
      wherein the speed regulating circuit is operative to modify the drive signals
      in response to changes in the present speed signal such that the present
      speed signal approaches one of the at least one target speed, whereby
      the speed of the vehicle tends to be maintained substantially constant
      during the attachment and release of the one or more shopping carts or
      shopping cart trains coupled to the vehicle
              (i) a brake controller operative to drive the electric motor in an
      opposite direction in response to the stop signal.

‘379 patent, col. 13, ll. 14-58 (emphasis added).

      Two claim limitations at issue in this case are “locking means,” in the ‘694 patent,

and “a brake controller,” in the ‘379 patent. The district court construed the locking

means limitation to require “a pin that can be moved across an open portion of one of

the two jaws to prevent the vertical frame member of the wheeled cart from being

removed from the jaw.” Finding this element not present in the Golden Retriever, the

court determined that the Golden Retriever did not infringe the ‘694 patent. As to the

brake controller limitation, the court adopted the following construction: “[t]he brake

controller is an electrical device or mechanism that in response to a stop signal applies

power to the motor to command the motor to rotate in an opposite direction.” With



05-1056, -1070                               3
respect to this term, the court identified the dispositive issue as “whether any of the

Golden Retriever braking functions both respond to a stop signal and command the

motor to rotate in an opposite direction.” Answering this question in the negative, the

court found that the Golden Retriever did not infringe any of the claims of the ‘379

patent.

       As to Ameritek’s assertions that the ‘379 and ‘694 patents were invalid under

35 U.S.C. §§ 102, 103, the district court ruled that Ameritek could not challenge the

validity of the patents based on the doctrine of assignor estoppel.

       Dane appeals the district court’s claim construction and subsequent infringement

determinations, and Ameritek cross appeals the district court’s finding of the applicability

of assignor estoppel. We have jurisdiction pursuant to 28 U.S.C. § 1292(c)(1).

                                                 II

       We review a district court’s grant of summary judgment without deference.

Kemco Sales, Inc. v. Control Papers Co., 208 F.3d 1352, 1359 (Fed. Cir. 2000).

Summary judgment is appropriate when the record shows that no issues of fact remain

and that the moving party is entitled to judgment as a matter of law. Anderson v. Liberty

Lobby, Inc., 477 U.S. 242, 255 (1986).

       The claim construction underlying a district court’s grant of summary judgment is

a matter of law that we review de novo. AFG Indus., Inc. v. Cardinal IG Co., Inc., 239

F.3d 1239, 1244 (Fed. Cir. 2001). The determination of whether a patent claim reads

on an accused product is a question of fact. Pitney Bowes, Inc. v. Hewlett-Packard Co.,

182 F.3d 1298, 1304 (Fed. Cir. 1999).




05-1056, -1070                               4
         Finally, we review the issue of assignor estoppel under an abuse of discretion

standard. Carroll Touch, Inc. v. Electro Mech. Sys., Inc., 15 F.3d 1573, 1579 (Fed. Cir.

1993).

                                              III

                                              A

         An infringement analysis involves two steps:      “the proper construction of the

asserted claim and a determination as to whether the accused method or product

infringes the asserted claim as properly construed.” Vitronics Corp. v. Conceptronic,

Inc., 90 F.3d 1576, 1581-82 (Fed. Cir. 1996). Here the district court concluded that the

brake controller claimed in the ‘379 patent was “an electrical device or mechanism that

in response to a stop signal applies power to the motor to command the motor to rotate

in an opposite direction.”     To the extent the district court required that the brake

controller command the motor to physically rotate in an opposite direction, it erred.

         The ‘379 patent claims “a brake controller operative to drive the electric motor in

an opposite direction in response to the stop signal.” Neither party disagrees with the

general principle behind how braking occurs in the claimed invention:           a torque is

generated which acts to oppose the direction of the rotation of the armature (“negative

torque”), thereby acting as a brake and slowing the speed of the armature. Thus, it is

the creation of the negative torque that is meant by the phrase “drive the electric motor

in the opposite direction.” This construction is supported by the specification, which

repeatedly refers to “dynamic braking.” See ‘379 patent, col 2, ll. 16-18 (“The motor

utilizes dynamic braking for stopping the vehicle.”); ‘379 patent, col. 9, ll. 46-47 (“[T]he

controller 184 invokes the dynamic braking function.”); ‘379 patent, col. 12, ll. 12-13




05-1056, -1070                                5
(“When the pedal 19 is released, dynamic braking action slows the unit to a stop . . . .”).

One of ordinary skill in the art would appreciate that “dynamic braking” describes

generally a form of braking in which the current in the armature is reversed to create a

negative torque and thereby brake the motor. It does not call for the direction of the

physical rotation of the armature to change. Indeed, there is nothing in the patent’s

claim language or written description to suggest that the controller itself must directly

command the motor to physically rotate in the opposite direction.

       Dane is correct in its identification that “the physical rotation of the motor and the

force that drives the motor—the torque—are distinct phenomena that may operate in

opposite directions at the same time.” As explained above, the claim limitation does not

require the controller to command the motor to physically rotate in the opposite

direction.

       Given the arguably ambiguous language of the district court’s claim construction,

the parties also dispute whether the court did in fact read a physical rotation limitation

into its claim construction. The imposition of such a limitation is evident by the court’s

infringement analysis. The court stated that the “dispositive issue is whether any of the

Golden Retriever braking functions both respond to a stop signal and command the

motor to rotate in an opposite direction.”       In determining that one form of braking

performed by the Golden Retriever, restraint braking, did not meet the claim limitation,

the court stated “[r]estraint braking occurs in response to a stop signal, but the motor

rotates in the same direction as it slows to a stop” (emphasis added). Similarly, when

discussing regenerative braking, the court noted that

       Regenerative braking neither occurs in response to a stop signal nor
       commands the motor to rotate in an opposite direction[, because a]lthough



05-1056, -1070                               6
       the vehicle ultimately moves in an opposite direction in response to the
       operator’s command, regenerative braking only slows the motor to at or
       near zero. At that point, regenerative braking ends and the drive mode
       begins. Thus reversing directions entails two modes: the regenerative
       braking that slows the vehicle in one direction, and the drive mode that
       powers the vehicle in the opposite direction. It is the drive signal that
       commands the motor to operate in the opposite direction – not the brake
       signal.

This clearly suggests that the district court viewed physical rotation of the motor in the

opposite direction as a requirement of the claim limitation.1

       Accordingly, we reverse the district court’s claim construction to the extent it

requires physical rotation of the motor in the opposite direction and remand for further

proceedings consistent with our determination. We reach no conclusion as to whether

the plug, restraint, and regenerative braking of the Golden Retriever can be considered

dynamic braking or fall within the correct claim construction. Such determinations must

be made by the district court in the first instance.

                                              B

       Dane also asserts that the district court committed reversible error in applying the

two jaws element and the locking means element of the ‘694 patent to the Golden

Retriever. We agree with the district court that the Golden Retriever does not have a

“locking means” as construed by the district court, and therefore affirm its finding of

noninfringement.




       1
         In discussing the third form of braking available in the Golden Retriever, the
court makes a single statement that could possibly suggest that physical rotation in the
opposite direction is not required: “[p]lug braking reverses the field to initiate braking,
but it does not occur in response to a stop signal.” However, this single statement does
not overcome the court’s more detailed analysis as to how physical rotation of the motor
is necessary to meet the claim limitation.


05-1056, -1070                                7
       The district court construed the locking means claim limitation to mean “a pin that

can be moved across an open portion of one of the two jaws to prevent the vertical

frame member of the wheeled cart from being removed from the jaw.”

       As the district court noted, the “locking means element” requires a pin that moves

across an open portion of one of the jaws. The court further noted:

      Depending on the version of the Golden Retriever, either a pin or a plate is
      placed across the opening at the top of the cup to retain the wheel in the
      cup. Because a cup is not a jaw, a pin placed across the top of a cup is
      not the same as a pin moving across the open portion of a jaw.

We agree. A pin traversing the top of a cup, considered to be merely one side of the

jaw, is not the same as extending across the open portion between the two sides of the

jaw, which is what the claim requires. Accordingly, we affirm the district court’s grant of

summary judgment of noninfringement of the ‘694 patent.

                                            IV

       In its cross appeal, Ameritek asserts that the district court erred in finding

Ameritek was precluded from challenging the validity of the ‘379 and ‘694 patents under

the doctrine of assignor estoppel.     “Assignor estoppel is an equitable doctrine that

prevents one who has assigned the rights to a patent (or patent application) from later

contending that what was assigned is a nullity.” Diamond Scientific Co. v. Ambico, Inc.,

848 F.2d 1220, 1224 (Fed. Cir. 1988). “Thus, an assignor and parties in privity with the

assignor are estopped or barred from asserting invalidity defenses.” Pandrol USA, LP

v. Airboss Ry. Prods., Inc., No. 04-1069, 2005 WL 2264918, at *5 (Fed. Cir. 2005)

(citing Diamond Scientific, 848 F.2d at 1224).       Mere employment is insufficient to

establish privity. However, a company may be in privity with an assignor if the company




05-1056, -1070                              8
avails itself of the assignor’s knowledge and assistance to conduct the infringement.

Intel Corp. v U.S. Int’l Trade Comm’n, 946 F.2d 821, 839 (Fed. Cir. 1991).

      There is no dispute that 1) Stephan Dominguez (“Dominguez”) was an inventor

of the claimed subject matter; 2) Dominguez assigned the ‘379 and ‘694 patents to

Dane; 3) Ameritek was formed to compete directly with Dane; and 4) Dominguez joined

Ameritek as its sole employee within two months of its inception.                          Additionally,

Dominguez was hired specifically to design and develop a cart retriever machine to

compete with Dane. His direct involvement in Ameritek led to the alleged infringement,

as Ameritek clearly availed itself of his knowledge and assistance to conduct the alleged

infringement.    Accordingly, we cannot say the district court abused its discretion in

finding that Ameritek was estopped from challenging the validity of the ‘379 and ‘694

patents.

      Ameritek argues that the doctrine of assignor estoppel should not be applied

here for equitable purposes. Its premise lies in the argument that Dane should not be

permitted to hide behind the doctrine of assignor estoppel when it, through its president

Dan Johnson, engaged in inequitable conduct during the prosecution of the ‘379 and

‘694 patents after the invention had been assigned.                  Ameritek contends that under

these facts, there is no unfairness in holding Dane accountable and application of

assignor estoppel is unwarranted.

      This argument is not properly before us for review.                    Ameritek did not plead

unenforceability    in   its     counterclaims;       rather,   it    pled    invalidity   based     on

35 U.S.C. §§ 102, 103.         Ameritek did seek leave to amend its pleadings to add a

counterclaim for unenforceability; however, the district court did not rule on this motion




05-1056, -1070                                    9
and the motion became moot in view of the judgment before us on review. Accordingly,

we do not reach the issue of whether this case warrants formulation and application of

an exception to the doctrine of assignor estoppel.

                                           V

      For the reasons stated above, we reverse the district court’s grant of Ameritek’s

motion for summary judgment of noninfringement of the ‘379 patent and remand for

further proceedings, and we affirm the district court’s grant of Ameritek’s motion for

summary judgment of noninfringement of the ‘694 patent and its grant of Dane’s motion

for partial summary judgment that the ‘379 and ‘694 patents are not invalid.




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