Shanghai Meihao Electric, Inc. v. Leviton Manufacturing Co. ( 2007 )


Menu:
  •                          Note: This disposition is nonprecedential.
    United States Court of Appeals for the Federal Circuit
    2006-1272, -1488
    SHANGHAI MEIHAO ELECTRIC, INC.,
    Plaintiff-Appellee,
    v.
    LEVITON MANUFACTURING COMPANY, INC.,
    Defendant-Appellant.
    -----------------------------------------
    LEVITON MANUFACTURING COMPANY, INC.,
    Plaintiff-Appellant,
    v.
    UNIVERSAL SECURITY INSTRUMENTS, INC.
    and USI ELECTRIC, INC.,
    Defendants.
    Gary Hnath, Bingham McCutchen LLP, of Washington, DC, argued for plaintiff-
    appellee. Of counsel was Daniel S. Nooter.
    Barry G. Magidoff, Greenberg Traurig LLP, of New York, New York, argued for
    defendant-appellant. With him on the were Paul J. Sutton and Alan Tenenbaum.
    Appealed from: United States District Court for the District of Maryland
    Judge Andre M. Davis
    NOTE: This disposition is nonprecedential.
    United States Court of Appeals for the Federal Circuit
    2006-1272, -1488
    SHANGHAI MEIHAO ELECTRIC, INC.,
    Plaintiff-Appellee,
    v.
    LEVITON MANUFACTURING COMPANY, INC.,
    Defendant-Appellant.
    --------------------------------------------------------------------
    LEVITON MANUFACTURING COMPANY, INC.,
    Plaintiff-Appellant,
    v.
    UNIVERSAL SECURITY INSTRUMENTS, INC., and
    USI ELECTRIC, INC.,
    Defendants.
    __________________________
    DECIDED: January 10, 2007
    __________________________
    Before NEWMAN, Circuit Judge, CLEVENGER, Senior Circuit Judge, and DYK, Circuit
    Judge.
    CLEVENGER, Senior Circuit Judge.
    Declaratory judgment defendant Leviton Manufacturing Co., Inc. ("Leviton")
    appeals the February 15, 2006 order of the United States District Court for the District of
    Maryland (1) granting plaintiff Shanghai Meihao Electric, Inc.'s ("Meihao") motion for
    summary judgment of noninfringement of 
    U.S. Patent No. 6,040,967
     ("the '967 patent"),
    No. 6,246,558 ("the '558 patent"), No. 6,381,112 ("the '112 patent"), and No. 6,437,953
    ("the '953 patent"),1 and (2) entering a permanent injunction against Leviton. We affirm
    in part and reverse in part.
    I
    The patents at issue in this case relate to a reset lockout feature in a circuit
    interrupting device, such as a ground fault circuit interrupter ("GFCI"). A GFCI is a
    safety device used in conjunction with electric circuitry that "use[s] a trip mechanism to
    mechanically break an electrical connection between one or more input and output
    conductors" in the event of a ground fault.2 '967 patent col.1 ll.29-30. The broken
    electrical connection can subsequently be reset by depressing a reset button. After a
    reset under normal circumstances, the GFCI will allow current to resume flowing until
    another ground fault occurs, at which point the trip mechanism will break the connection
    once again. Occasionally, however, either an open neutral condition3 will develop in the
    power lines feeding the GFCI, or a ground fault will damage the GFCI to such an extent
    that it will be unable to detect future ground faults. In either case, it is desirable to
    prevent the GFCI from resetting until the problem has been remedied.
    1
    This action originally involved two additional patents—
    U.S. Patent No. 6,282,070
     and No. 6,288,882—which have subsequently dropped out of the case.
    2
    A ground fault occurs when an alternate current path is created from the
    circuit to ground, such as, for example, when an activated toaster is dropped into a
    water-filled bathtub.
    3
    An open neutral condition develops when the neutral line from the power
    source separates from the input terminals of the GFCI. In the prior art, an open neutral
    condition did not prevent the GFCI from resetting. Although an appliance plugged into a
    receptacle having a reset GFCI will not function so long as the open neutral condition
    persists, the reset GFCI may still allow a dangerous path to ground from a metal surface
    on the appliance to be created. Appellant's Br. at 4.
    2006-1272, -1488                            2
    The patents in suit all relate in one way or another to providing a reset lockout
    feature that prevents the GFCI from resetting unless certain conditions are met. The
    relevant portions of the claims at issue are reproduced below:
    1. A circuit interrupting device comprising:
    ...
    a reset lock-out responsive to the occurrence of said predefined condition
    such that said reset lock-out is operable between a lock-out position
    wherein said reset lock-out inhibits resetting of said electrical connection
    between said input and output conductors and a reset position wherein
    said reset lock-out does not inhibit resetting of said electrical connection
    between said input and output conductors; and
    a reset mechanism operatively associated with said reset lock-out and
    said circuit interrupter such that activation of said reset mechanism
    activates said circuit interrupter which facilitates movement of said reset
    lock-out from said lock-out position to said reset position by said reset
    mechanism.
    ...
    7. A ground fault circuit interrupting device comprising:
    ...
    a reset mechanism having a reset lock-out responsive to activation of said
    circuit interrupter so as to be movable between a lock-out position wherein
    said reset lock-out inhibits resetting of said electrical connection between
    said input and output conductors and a reset position wherein said reset
    lock-out does not inhibit resetting of said electrical connection between
    said input and output conductors, wherein when said reset mechanism is
    activated said circuit interrupter is activated to facilitates movement of said
    reset lock-out from said lock-out position to said reset position by said
    reset mechanism and resets said electrical connection between said input
    and output conductors.
    ...
    12. A circuit interrupting device comprising:
    ...
    reset lock-out means responsive to activation of said circuit interrupting
    means for inhibiting resetting of said electrical connection between said
    input and output conductor means after said circuit interrupting means
    breaks said connection between said input and output conductor means;
    and
    2006-1272, -1488                            3
    reset means disposed within said housing means for activating said circuit
    interrupting means so that said lock-out means does not inhibit resetting of
    said electrical connection between said input and output conductor means
    and for resetting said electrical connection between said input and output
    conductor means.
    '967 patent col.6 l.53–col.8 l.49 (emphasis added).
    1. A circuit interrupting device comprising:
    ...
    said circuit interrupting device further comprising a reset lockout portion
    that prevents reestablishing electrical continuity in said phase and neutral
    conductive paths if said circuit interrupting portion is non-operational, if an
    open neutral condition exists or if a reverse wiring condition exists,
    wherein said reset portion comprises:
    a reset button; and
    at least one reset contact which when depressed is capable of contacting
    at least a portion of said phase conductive path to cause said
    predetermined condition, wherein if said circuit interrupting portion is
    operational, the circuit interrupting portion is activated to disable said reset
    lockout portion and facilitate reestablishing electrical continuity in said
    phase and neutral conductive paths, and wherein if said circuit interrupting
    portion is non-operational, said reset lockout portion remains enabled so
    that reestablishing electrical continuity in said phase and neutral
    conductive paths is prevented.
    2. A circuit interrupting device comprising:
    ...
    said circuit interrupting device further comprising a reset lockout portion
    that prevents the making of electrical continuity between said first and
    second conductive paths and between said first and third conductive
    paths, if said circuit interrupting portion is non-operational;
    and wherein said reset portion comprises:
    a reset button; and
    at least one reset contact which when depressed is capable of contacting
    at least a portion of one of said first or second conductive paths to cause
    said predetermined condition, wherein if said circuit interrupting portion is
    operational, said circuit interrupting portion is activated to disable said
    2006-1272, -1488                             4
    reset lockout portion and facilitate making of electrical continuity between
    said first and second conductive paths and between said first and third
    conductive paths, and wherein if said circuit interrupting portion is non-
    operational, said reset lockout portion remains enabled so that making of
    electrical continuity between said first and second conductive paths and
    between said first and third conductive paths is prevented.
    ...
    4. A circuit interrupting system comprising:
    ...
    said circuit interrupting device further comprising a reset lockout portion
    that prevents reestablishing electrical continuity in said phase and neutral
    conductive paths if said circuit interrupting portion is non-operational or if
    an open neutral condition exists;
    and wherein said reset portion comprises:
    a reset button; and
    at least one reset contact which when depressed is capable of contacting
    at least a portion of said phase conductive path to cause said
    predetermined condition, wherein if said circuit interrupting portion is
    operational, said circuit interrupting portion is activated to disable said
    reset lockout portion and facilitate reestablishing electrical continuity in
    said phase and neutral conductive paths, and wherein if said circuit
    interrupting portion is non-operational, said reset lockout portion remains
    enabled so that reestablishing electrical continuity in said phase and
    neutral conductive paths is prevented.
    '558 patent col.11 l.62–col.14 l.52 (emphasis added).
    1. A circuit interrupting device comprising:
    ...
    a circuit interrupter disposed within said housing, the circuit interrupter
    having an operational state and a non-operational state and configured to
    break the continuity between said first and second conductive paths upon
    the occurrence of a predetermined condition;
    a reset mechanism configured to make electrical continuity between the
    first and second conductive paths after said predetermined condition
    occurs; and
    2006-1272, -1488                            5
    a reset lock-out that prevents the making of electrical continuity between
    said first and second conductive paths if said circuit interrupter is in the
    non-operational state; and
    wherein activation of the reset mechanism activates the circuit interrupter
    to be in the operational state to move the reset lock-out to a reset position.
    ...
    5. A circuit interrupting device comprising:
    ...
    a reset lock-out that prevents reestablishment of electrical continuity
    between said first and second conductors if said circuit interrupter is non-
    operational.
    ...
    22. A circuit interrupting device comprising:
    ...
    a circuit interrupter disposed within said housing, the circuit interrupter
    having an operational state and a non-operational state and configured to
    cause electrical discontinuity between said first and second conductors
    upon the occurrence of a predetermined condition;
    a reset device configured to reestablish electrical continuity between the
    first and second conductors after said discontinuity is caused; and
    a reset lock-out device that prevents reestablishment of electrical
    continuity between said first and second conductors if said third electrical
    conductor is not connected to a neutral line; and
    wherein activation of the reset device activates the circuit interrupter to be
    in the operational state to move the reset lock-out device to a reset
    position.
    '112 patent col.6 l.54–col.10 l.24 (emphasis added).
    1. A reset lockout device comprising:
    ...
    a reset actuator lockout connected to the reset actuator for blocking the
    enabling of the switch reset unless the test succeeds.
    ...
    14. A circuit interrupting device for use with an electrical wiring system
    having at least one conductor comprising:
    2006-1272, -1488                            6
    ...
    a reset lockout portion that prevents reestablishing electrical continuity in
    said first conductive path and said second conductive path if said circuit
    interrupter is non-operational or if an open neutral condition exists;
    wherein activation of said reset portion first simulates at least one of the
    predetermined conditions, wherein if said circuit interrupter is operational,
    the circuit interrupter causes said reset lockout portion to be disabled to
    facilitate reestablishing electrical continuity in said first and second
    conductive paths.
    '953 patent col.11 l.60–col.14 l.28 (emphasis added).
    II
    Meihao filed this declaratory judgment action on July 23, 2003, seeking a
    declaration that it does not infringe the Leviton patents mentioned above. On March 3,
    2005, the district court held a claim construction hearing, and subsequently issued a
    thirty-six page written opinion construing the disputed claim limitations.       Shanghai
    Meihao Elec., Inc. v. Leviton Mfg. Co., Inc., No. 03-2137 (D. Md. Apr. 22, 2005) ("Claim
    Construction Opinion").
    Although there were many disputed limitations among the several patents in suit,
    the district court's summary judgment decisions turned on two groups of disputed claim
    terms: the "operational" terms and the "reset lock-out" terms.4         The district court
    construed the terms in each group as follows:
    [T]he term "operational" must be construed to mean "working properly,"
    and further, that both the sensing circuitry and the trip mechanism must be
    working properly. When the circuit interrupter is "operational," it is able to
    sense a fault and interrupt electrical continuity in response to the fault.
    "Non-operational" is the opposite of "operational" and must mean that the
    sensing circuitry or the trip mechanism, or both, are not working properly,
    4
    The terms in each of these groups are emphasized in the claims recited
    above.
    2006-1272, -1488                            7
    such that the circuit interrupter is either not able to detect a fault or not
    able to interrupt the electrical continuity when the fault occurs, or both.
    
    Id.,
     slip op. at 32 (emphasis added).
    [A] "reset lock-out" must be construed as the latching finger of the latching
    member working in cooperation with the contact arm, and equivalents
    thereof that perform the identical function of inhibiting the resetting of the
    electrical connection unless the circuit interrupter is operational.
    
    Id.,
     slip op. at 20-21 (emphasis added).
    On July 15, 2005, Meihao moved for summary judgment of noninfringement of all
    asserted claims, and for a permanent injunction to preclude Leviton from pursuing suits
    involving the same patents and the same accused products. Leviton responded on
    August 9, 2005, with a cross-motion for summary judgment of infringement of claims 5
    and 22 of the '112 patent. The court first considered Leviton's motion and concluded
    that the Meihao GFCIs do not infringe, either literally or under the doctrine of
    equivalents, because they do not test the fault sensing circuitry as required by the
    claims before allowing themselves to be reset. The court next considered Meihao's
    motion and held that the accused devices do not literally infringe the claims because
    they do not have a "reset lock-out" that prevents resetting if the circuit interrupter is non-
    operational.   The court further held that there could be no infringement under the
    doctrine of equivalents because the function of the "reset lock-out" limitations is not met
    by the accused devices.
    Accordingly, the court denied Leviton's motion and granted Meihao's motion.
    Shanghai Meihao Elec., Inc. v. Leviton Mfg. Co., Inc., No. 03-2137 (D. Md. Jan. 18,
    2006) ("Summary Judgment Opinion"). Pursuant to Meihao's motion, but without any
    2006-1272, -1488                              8
    explanation, the district court also entered a permanent injunction which read in relevant
    part:
    ORDERED that [Leviton] is hereby enjoined from in any way suggesting,
    asserting, advising, or claiming to third parties, including but not limited to
    Meihao's customers and their customers, that Meihao's GFCIs infringe the
    Leviton Lockout Patents asserted in this action by Leviton against
    Meihao's GFCIs, or suing or threatening a lawsuit for infringement of the
    Leviton Lockout Patents against third parties based on their use, sale or
    offer for sale of Meihao's GFCIs.
    Shanghai Meihao Elec., Inc. v. Leviton Mfg. Co., Inc., No. 03-2137 (D. Md. Jan. 18,
    2006). Shortly after the entry of this injunction, Leviton filed a motion for an order to
    show cause why the injunction should not be stricken, arguing that the injunction did not
    comply with Federal Rule of Civil Procedure 65(d) in terms of scope, specificity, or
    rationale. Leviton further argued that the injunction was improper because there had
    been no finding of "necessity," as required by the Fourth Circuit. Leviton's motion was
    at least partially denied:
    The motion for show cause is hereby DENIED.
    That said, I agree with Leviton that the form of order entered in this
    case lacks the specificity and precision that it has a right to insist upon.
    Obviously, I simply employed the form of order proposed by plaintiff here.
    Nevertheless, I see no need for the sort of protracted contentiousness that
    has characterized the Leviton cases.
    Leviton's proposed [alternative] order is as inappropriate for its
    sparseness as is the extant order for its clumsiness. The parties are
    directed to confer and agree upon an appropriate order and submit same
    on or before February 10, 2006. The court has no intention to infringe on
    Leviton's First Amendment rights to say whatever it chooses to say about
    anything.
    JA at A3404.
    Pursuant to the direction of the district court, the parties thereafter agreed upon
    suitable language:
    2006-1272, -1488                              9
    ORDERED that [Meihao's] Motion for Summary Judgment of Non-
    Infringement is granted and that the Summary Judgment of Non-
    Infringement on behalf of Meihao is hereby entered in accordance with the
    Court's January 18, 2006 Memorandum Opinion, and it is further
    ORDERED that this Court having found as a matter of law that
    Meihao's GFCIs do not infringe the claims of the Leviton Reset Lockout
    patents asserted in this action (
    U.S. Patent No. 6,040,967, U
    .S. Patent
    No. 6,381,112, 
    U.S. Patent No. 6,437,953, U
    .S. Patent No. 6,246,558
    (only claims 1, 2 and 4), 
    U.S. Patent No. 6,282,070
     and/or 
    U.S. Patent No. 6,288,882
    ), [Leviton] and its officers, agents, servants, employees and
    attorneys . . ., and those persons in active concert or participation with
    them, are hereby enjoined from initiating any suit for infringement of the
    aforesaid claims against anyone who has or does hereafter buy, sell, offer
    for sale, import or use a Meihao GFCI. "Meihao GFCIs" are those ground
    fault circuit interrupters which were the subject of the Court's
    Memorandum Opinion granting Meihao's Motion for Summary Judgment
    of Non-Infringement dated January 18, 2006, specifically, Meihao GFCIs
    having the structure and operation as described in the Court's
    Memorandum Opinion and as sold in the United States during the years
    2003 and 2004, bearing UL File Nos. E220379, E197052, and E224920
    and subsequent Meihao GFCIs substantially identical thereto as to their
    structure and operation. Nothing in this Order is intended to, or shall,
    prevent Leviton from submitting, or allow Leviton to submit, pleadings,
    motions or other documents in litigations that were ongoing as of January
    18, 2006, to the extent those litigations involve Meihao's GFCIs, or filing a
    notice of appeal and prosecuting any appeal in this action from this
    Judgment, nor from exercising its rights under the First Amendment to the
    U.S. Constitution by stating accurately any facts relating to the judgment,
    and the effect of a successful appeal, as well as its opinion as to what the
    result of such appeal may be, but will not otherwise assert infringement or
    threaten suit for infringement with respect to Meihao GFCIs under the
    aforesaid claims of the Leviton Reset Lockout patents.
    JA at A32-A33.     The district court also agreed to this language, and entered the
    permanent injunction on February 15, 2006. Shanghai Meihao Elec., Inc. v. Leviton
    Mfg. Co., Inc., No. 03-2137 (D. Md. Feb. 15, 2006).
    This appeal followed. We have jurisdiction pursuant to 
    28 U.S.C. § 1295
    (a).
    2006-1272, -1488                           10
    III
    "We review the district court's claim construction and the grant of summary
    judgment based thereon without deference." Novartis Pharm. Corp. v. Eon Labs Mfg.,
    
    363 F.3d 1306
    , 1308 (Fed. Cir. 2004).
    Where the question on appeal involving the issuance of an injunction is whether
    the District Court complied with the procedural requirements of the Federal Rules of
    Civil Procedure, we review that question under the law of the applicable circuit. See
    Biodex Corp. v. Loredan Biomedical, Inc., 
    946 F.2d 850
    , 857 n.10 (Fed. Cir. 1991)
    (collecting cases); Chemlawn Servs. Corp. v. GNC Pumps, Inc., 
    823 F.2d 515
    , 517
    (Fed. Cir. 1987); Digital Equip. Corp. v. Emulex Corp., 
    805 F.2d 380
    , 382 n.3 (Fed. Cir.
    1986) (failure to provide reasons for issuance of injunction reviewed under regional
    circuit law). In this case, the law of the Fourth Circuit controls. Applying the law of that
    circuit, "[w]e review the grant of a permanent injunction for an abuse of discretion." Belk
    v. Charlotte-Mecklenburg Bd. of Educ., 
    269 F.3d 305
    , 347 (4th Cir. 2001). "Of course,
    underlying factual findings are reviewed for clear error, and legal conclusions are
    reviewed de novo." Va. Soc'y for Human Life, Inc. v. FEC, 
    263 F.3d 379
    , 392 (4th Cir.
    2001).5
    5
    To be sure, this court applies its own law in cases where the question
    presented, although procedural in nature, "bears an essential relationship to matters
    committed to our exclusive control by statute." Biodex, 
    946 F.2d at 858-59
    . Here,
    although Leviton's appeal of the injunction entered below does not appear to have "an
    essential relationship" to our jurisdiction, we need not decide whether to apply our law
    instead of Fourth Circuit law because we also review the grant of a permanent
    injunction for abuse of discretion. Cross Med. Prods., Inc. v. Medtronic Sofamor Danek,
    Inc., 
    424 F.3d 1293
    , 1301-02 (Fed. Cir 2005).
    2006-1272, -1488                            11
    IV
    The crux of this appeal is the district court's construction of the "operational"
    terms and the "reset lock-out" terms. We address each of these, and then we turn to
    the permanent injunction.
    A
    With respect to "operational," Leviton focuses on the use of that term in claims 5
    and 22 of the '112 patent by arguing that the district court improperly imported
    limitations from a preferred embodiment into the claims.           Leviton's most coherent
    argument in this regard relates to claim 22, which reads in relevant part:
    22. A circuit interrupting device comprising:
    ...
    a circuit interrupter disposed within said housing, the circuit interrupter
    having an operational state and a non-operational state and configured to
    cause electrical discontinuity between said first and second conductors
    upon the occurrence of a predetermined condition;
    ...
    a reset lock-out device that prevents reestablishment of electrical
    continuity between said first and second conductors if said third electrical
    conductor is not connected to a neutral line; and
    wherein activation of the reset device activates the circuit interrupter to be
    in the operational state to move the reset lock-out device to a reset
    position.
    '112 patent col.9 l.17–col.10 l.24 (emphasis added).
    According to Leviton, the plain language of the second limitation reproduced
    above ("a reset lock-out device . . .") demonstrates that claim 22 only prevents
    reestablishment of electrical continuity if there is an open neutral condition, i.e., the third
    wire "is not connected to a neutral line." As such, the "operational state" of the circuit
    interrupter referenced in the "wherein" clause is satisfied so long as the circuit
    interrupter is able "to move the reset lock-out device to a reset position."
    2006-1272, -1488                              12
    Although we agree that activation of the circuit interrupter to be in the operational
    state is necessary to move the reset lock-out position, the remainder of Leviton's
    argument is unpersuasive because it ignores the first limitation reproduced above ("a
    circuit interrupter disposed . . ."), which plainly ties the "operational state" of the circuit
    interrupter to the ability of the circuit interrupter to "cause electrical discontinuity . . .
    upon the occurrence of a predetermined condition."6 The ability of the circuit interrupter
    to cause discontinuity requires, as Leviton admits, both the sensing circuitry and the trip
    mechanism to be working properly. Appellant's Br. at 3-4. Accordingly, "activat[ing] the
    circuit interrupter to be in the operational state" must also require both the sensing
    circuitry and the trip mechanism to be working properly.            This requirement is not
    inconsistent with, and does nothing to eliminate, the additional requirement of claim 22
    that the reset lock-out device must prevent reestablishment of electrical continuity in the
    event of an open neutral condition.
    Leviton attempts to draw an even finer linguistic distinction with respect to claim 5
    of the '112 patent:
    Claim 5 does not discuss a device in terms of "operational," it recites a
    device which will not allow itself to be reset if any one of its circuit
    interrupter components is "non-operational." Accordingly, there was no
    basis to limit the claim to a device that will allow reestablishment of
    electrical continuity only after a complete test of the system to show that it
    is fully operational.
    6
    Such "predetermined conditions" include ground faults, arc faults,
    appliance leakage faults, immersion faults, and test cycles. '112 patent col.2 ll.27-28.
    However, an open neutral condition is not a "predetermined condition" because an open
    neutral condition cuts off power to the trip mechanism of the circuit interrupter. See 
    id.
    col.3 ll.45-54. And it is axiomatic that if the trip mechanism—which is "electro-
    mechanical," 
    id.
     col.3 ll.8-9—has no power, it cannot cause electrical discontinuity.
    Thus, if an open neutral condition could be one of the "predetermined conditions," the
    circuit interrupter could not fulfill its stated purpose because it could not be configured to
    cause discontinuity in response to such a condition.
    2006-1272, -1488                              13
    Appellant's Br. at 25 (emphasis in original).
    We disagree. There is simply no way for the device to know in advance which of
    its circuit interrupter components, if any, are not working properly. Therefore, the device
    must, as the district court held, be capable of testing both the sensing circuitry and the
    trip mechanism in order to determine whether the circuit interrupter is operational. To
    be sure, a situation may arise in which the first of those two components is found to be
    malfunctioning, thereby rendering a test of the second component unnecessary. That
    does not mean, however, that both components need not be tested before electrical
    continuity is reestablished.
    Leviton further argues with respect to claim 5 that the doctrine of claim
    differentiation precludes the district court's construction of "non-operational" because
    dependent claims 12 and 13 respectively describe preventing the reestablishment of
    electrical continuity "if said trip mechanism is non-operational," and "if said sensing
    circuitry is non-operational."   '112 patent col.7 l.66 – col.8 l.6.    Thus, according to
    Leviton, independent claim 5 is actually narrower than dependent claims 12 and 13
    under the district court's claim construction. See Appellant's Reply Br. at 9-11. "As this
    court has frequently stated, 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." Liebel-Flarsheim Co. v. Medrad, Inc., 
    358 F.3d 898
    , 910 (Fed. Cir.
    2004). However, "that presumption can be overcome if the circumstances suggest a
    different explanation, or if the evidence favoring a different claim construction is strong."
    
    Id.
     Here, the presumption is clearly overcome because, as explained in the preceding
    paragraph, the device must be capable of testing both the sensing circuitry and the trip
    2006-1272, -1488                             14
    mechanism in order to determine whether the circuit interrupter is operational. If, as
    Leviton suggests, electrical continuity could be reestablished when only the trip
    mechanism is operational, or when only the sensing circuitry is operational, the circuit
    interrupter would remain non-operational and the device would not function properly,
    i.e., it would not cause electrical discontinuity upon the occurrence of a predetermined
    condition. Therefore, claim differentiation does not apply in this case.
    Because we are not persuaded by Leviton's arguments, we see no need to
    disturb the district court's construction of "operational."
    B
    The thrust of Leviton's "reset lock-out" argument is that the district court
    improperly held that the function of the reset lock-out is to inhibit the reestablishment of
    electrical continuity unless the circuit interrupter is operational. Leviton points out that
    the reset lock-out can also inhibit the reestablishment of electrical continuity if there is
    an open neutral condition or if the circuit interrupting device is reverse wired.        For
    example, the "reset lock-out" limitation in claim 1 of the '558 patent reads:
    said circuit interrupting device further comprising a reset lockout portion
    that prevents reestablishing electrical continuity in said phase and neutral
    conductive paths if said circuit interrupting portion is non-operational, if an
    open neutral condition exists or if a reverse wiring condition exists[;]
    '558 patent col.12 ll.20-25 (emphasis added). Thus, according to Leviton, electrical
    continuity can be reestablished in some embodiments even if the circuit interrupter is
    non-operational.
    We are not persuaded. Leviton's argument is essentially that the district court's
    construction requires "or" to be replaced with "and." However, the conditional statement
    in the excerpt above (i.e., "a reset lockout portion that prevents reestablishing electrical
    2006-1272, -1488                              15
    continuity . . . if said circuit interrupting portion is non-operational, if an open neutral
    condition exists or if a reverse wiring condition exists") is exactly the same as the
    following conditional statement: "a reset lockout portion that permits reestablishing
    electrical continuity . . . only if said circuit interrupting portion is operational, an open
    neutral condition does not exist, and a reverse wiring condition does not exist." It is
    therefore clear that, even in those claims where additional features are incorporated
    through "or if" statements, the circuit interrupter must be operational in order to
    reestablish electrical continuity.   As such, Leviton has not demonstrated a need to
    reverse the district court's construction. Because Leviton provides us with no alternative
    basis on which to disturb the summary judgment of noninfringement entered below, we
    affirm that portion of the district court's order on appeal.
    C
    In granting permanent injunctions, district courts are bound by the requirements
    set forth in Federal Rule of Civil Procedure 56, which provides in relevant part:
    Form and Scope of Injunction or Restraining Order. (d) Every order
    granting an injunction and every restraining order shall set forth the
    reasons for its issuance; shall be specific in terms; shall describe in
    reasonable detail, and not by reference to the complaint or other
    document, the act or acts sought to be restrained; and is binding only
    upon the parties to the action, their officers, agents, servants, employees,
    and attorneys, and upon those persons in active concert or participation
    with them who receive actual notice of the order by personal service or
    otherwise.
    Fed. R. Civ. P. 56(d) (emphasis added).             Moreover, "[b]efore a court grants a
    permanent injunction, the court must first find necessity – a danger of future violations."
    Belk, 
    269 F.3d at 347
    .
    2006-1272, -1488                              16
    On its face, the injunction entered by the district court, while specific and
    reasonably detailed, plainly fails to "set forth the reasons for its issuance." The only
    arguable reason for the injunction was enunciated in the district court's order denying
    Leviton's motion to show cause: "I see no need for the sort of protracted
    contentiousness that has characterized the Leviton cases."             Such a reason is
    insufficient as a matter of law. Patent litigation is often both protracted and contentious.
    Were that the appropriate standard, every losing litigant would be a permanent-
    injunction candidate.
    We also discern no "necessity" for a permanent injunction. The present case is
    unlike Kessler v. Eldred, 
    206 U.S. 285
     (1907).         There, Kessler and Eldred were
    competitors in the business of selling electric cigar lighters. Eldred owned a patent for
    an electric lamp lighter and sued Kessler for patent infringement in the District of
    Indiana. Kessler prevailed, and a judgment of noninfringement was entered in his favor.
    Eldred then sued Breitwieser, a user of the very Kessler lighters previously held to be
    noninfringing, in the Western District of New York.       Kessler assumed Breitwieser's
    defense, and, in light of the previous judgment of noninfringement, sought to enjoin
    Eldred from pursuing any further lawsuits against users of Kessler's lighters.
    Under these facts, the Supreme Court concluded that such an injunction was
    necessary:
    The effect which may reasonably be anticipated of harassing the
    purchasers of Kessler's manufactures by claims for damages on account
    of the use of them, would be to diminish Kessler's opportunities for sale.
    No one wishes to buy anything, if with it he must buy a law suit. That the
    effect to be anticipated was the actual effect of the Breitwieser suit is
    shown by the statement of facts. Kessler's customers ceased to send
    orders for lighters, and even refused to pay for those which had already
    been delivered. Any action which has such results is manifestly in
    2006-1272, -1488                            17
    violation of the obligation of Eldred, and the corresponding right of
    Kessler, established by the judgment. Leaving entirely out of view any
    rights which Kessler's customers have or may have, it is Kessler's right
    that those customers should, in respect of the articles before the court in
    the previous judgment, be let alone by Eldred, and it is Eldred's duty to let
    them alone. The judgment in the previous case fails of the full effect
    which the law attaches to it if this is not so. If rights between litigants are
    once established by the final judgment of a court of competent jurisdiction
    those rights must be recognized in every way, and wherever the judgment
    is entitled to respect, by those who are bound by it. Having then by virtue
    of the judgment the right to sell his wares freely without hindrance from
    Eldred, must Kessler stand by the see that right violated, and then bring
    an action at law for the resulting damage, or may he prevent the infliction
    of the unlawful injury by proceedings in personam in equity? If Eldred
    succeeds in his suit against one of Kessler's customers, he will naturally
    bring suits against others. He may bring suits against others, whether he
    succeeds in one suit or not. There may be and there is likely to be a
    multiplicity of suits. It is certain that such suits if unsuccessful would at the
    same time tend to diminish Kessler's sales and to impose upon him the
    expense of defending many suits in order to maintain the right which by a
    judgment has already been declared to exist. If the suits are successful
    the result will be practically to destroy Kessler's judgment right.
    
    Id. at 289-90
    .
    Here, by contrast, there is no evidence that Leviton has exhibited, or intends to
    exhibit, the same cavalier attitude toward the judgment entered against it as Eldred
    exhibited toward the judgment entered against him. Leviton, as the owner of several
    issued patents, none of which have been declared invalid, is well within its rights to
    enforce those patents. And until recently, Leviton had not lost a case against Meihao's
    GFCIs.    In the absence of frivolity, such enforcement actions do not establish a
    "necessity" for a permanent injunction of the type entered against it below. Therefore,
    we reverse the district court's order to the extent it permanently enjoins Leviton.
    2006-1272, -1488                              18
    V
    In sum, we affirm the district court's entry of summary judgment in favor of
    Meihao and we reverse the district court's entry of a permanent injunction against
    Leviton.
    COSTS
    No costs.
    2006-1272, -1488                       19