Cequent Performance Products, Inc. v. Hopkins Manufacturing Corporation et al

Filing 66

OPINION and ORDER Construing Disputed Claim Limitations. Signed by District Judge Matthew F. Leitman. (HMon)

UNITED STATES DISTRICT COURT
EASTERN DISTRICT OF MICHIGAN
SOUTHERN DIVISION
CEQUENT PERFORMANCE
PRODUCTS, INC.,
Plaintiff,

Case No. 13-cv-15293
Hon. Matthew F. Leitman

v.
HOPKINS MANUFACTURING
CORPORATION et al.,
Defendants.
________________________________________/
OPINION AND ORDER CONSTRUING
DISPUTED CLAIM LIMITATIONS
This is a patent infringement case. Plaintiff Cequent Performance Products,
Inc. (“Cequent”) alleges that Defendant Hopkins Manufacturing Corporation
(“Hopkins”) has infringed upon three of its patents: U.S. Patent Nos. (1) 6,068,352,
entitled “Microprocessor-Based Control for Trailer Brakes” (“the ‘352 Patent”); (2)
6,012,780, entitled “Brake Controller for Trailer Brakes” (“the ‘780 Patent”); and
(3) 6,445,993, entitled “Brake Control Unit” (“the ‘993 Patent”) (collectively, the
“Patents”). The Patents are directed to electronic brake controllers that activate the
brakes on a trailer being towed by a vehicle.
Cequent and Hopkins have now identified ten claim limitations from the
Patents that are in dispute. (See ECF ## 42, 47.) In this Opinion and Order, the Court

1

will construe the disputed claim limitations pursuant to Markman v. Westview
Instruments, 517 U.S. 370 (1996).
I
“The construction of claims is simply a way of elaborating the normally terse
claim language[] in order to understand and explain, but not to change, the scope of
the claims.” Embrex, Inc. v. Service Engineering Corp., 216 F.3d 1343, 1347 (Fed.
Cir. 2000) (quoting Scripps Clinic & Research Found. v. Genentech, Inc., 927 F.2d
1565, 1580 (Fed. Cir. 1991)). The judge, not a jury, is to determine the meaning of
the disputed claim limitations as a matter of law. See Markman, 517 U.S. at 372,
391.
The Federal Circuit has summarized the law of claim construction as follows:
Claim construction requires a determination as to how a
person of ordinary skill in the art would understand a claim
term in the context of the entire patent, including the
specification. We begin a claim construction analysis by
considering the language of the claims themselves.
However, claims must be read in view of the specification,
of which they are a part. The specification is the single best
guide to the meaning of a disputed term, and is, thus, the
primary basis for construing the claims. A court should
also consider the patent's prosecution history, and may
rely on dictionary definitions, so long as the dictionary
definition does not contradict any definition found in or
ascertained by a reading of the patent documents.
[….]
Phillips [v. AWH Corp., 415 F.3d 1303, 1315 (Fed. Cir.
2005)] makes clear that the claims do not stand alone.
2

Rather they are part of a fully integrated written instrument,
consisting principally of a specification that concludes
with the claims. The only meaning that matters in claim
construction is the meaning in the context of the patent.
Trustees of Columbia Univ. v. Symantec Corp., 811 F.3d 1359, 1362-63 (Fed. Cir.
2016) (internal punctuation and citations omitted).
II
In their claim-construction briefs (see ECF ## 42, 47), Cequent and Hopkins
have requested that the Court construe ten claim limitations from the Patents: four
from the ‘352 Patent, three from the ‘780 Patent, and three from the ‘993 Patent.
The Court will address each claim limitation individually below.
A.

The ‘352 Patent
1.

Background on the ‘352 Patent

Many small trailers like campers or boat trailers use electronic brakes. (See
Decl. of Dr. Mark N. Horenstein at ¶20, ECF #47-2 at 8, Pg. ID 1354.) It is important
for these small trailers to have their own braking systems because “[w]ithout trailer
brakes to supplement the brakes of the towing vehicle, the trailer could swerve or
jackknife upon braking of the [towing] vehicle.” (Id. at ¶19, ECF #47-2 at 8, Pg. ID
1354.) The ‘352 Patent is directed to an electronic brake controller that uses a
microcontroller in conjunction with analog circuit technology to control the brakes
of a trailer that is being towed by an automobile.

3

2.

“an input circuit . . .” of Claims 1, 19, and 64 of the ‘352 Patent

Hopkins requests that the Court construe the claim limitation “an input circuit
for generating a brake level signal representing the braking force to be applied by
the towed vehicle’s brakes” in Claims 1, 19, and 64 of the ‘352 Patent.
Claim 1 of the ‘352 Patent, representative of the asserted claims, is reproduced
below with the disputed claim limitation bolded and underlined:
1. A brake controller for controlling the brakes of a towed
vehicle, said brake controller comprising:
an input circuit for generating a brake level signal
representing the braking force to be applied by the
towed vehicle's brakes;
a display circuit including a plurality of indicator lights;
a power switching circuit and adapted for coupling to the
brakes of the towed vehicle and to the power supply of the
towing vehicle, for selectively supplying power from the
towing vehicle power supply to the brakes of the towed
vehicle in response to a switching control signal supplied
to a control input terminal;
a current sensing circuit for sensing a level of braking
current supplied to the brakes of the towed vehicle through
said power switching circuit, and for generating a current
level signal representing the sensed level of braking
current; and
a microcontroller coupled to said input circuit, said display
circuit, said current circuit, and to said power switching
circuit, said microcontroller generating and supplying a
switching control signal to said control input terminal of
said power switching circuit thereby causing said power
switching circuit to deliver a braking current to the brakes
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of the towed vehicle that is related to the brake level signal
supplied to said microcontroller by said input circuit, said
microcontroller illuminating one or more of said indicator
lights of said display circuit to indicate a relative level of
braking of the towed vehicle brakes and controlling one or
more of said indicator lights to indicate that the towed
vehicle brakes are or are not properly connected to said
power switching circuit.
(‘352 Pat. at col. 39, ll. 28-60, ECF # 38-6 at 63, Pg. ID 924; emphasis added.)
Cequent and Hopkins disagree about whether or not this claim limitation is a
means-plus-function claim limitation pursuant to 35 U.S.C. § 112.
Hopkins argues that this claim limitation is a means-plus-function claim
limitation. Hopkins asserts that the corresponding structure in the specification for
this claim limitation is “a pendulum-style single axis decelerometer made of an
infrared LED, a phototransistor, and a mechanical flag that modulates the LED’s
light incident on the photoresistor to supply a single variable voltage to a pin of a
microcontroller that directly corresponds to the magnitude of the current to be
applied to the towed vehicles brakes. The function is to generate a signal that
directly corresponds to the brake current amperage to be applied to the towed vehicle
brakes.” (Hopkins Claim Const. Br. at 42-43, ECF #47 at 49-50, Pg. ID 1329-30.)
In contrast, Cequent argues that this claim limitation is not a means-plusfunction claim limitation. Cequent also argues that this claim limitation does not
need to be construed because the jury will understand its plain and ordinary meaning.
In the alternative, Cequent argues that this claim limitation should be construed as
5

corresponding structure, material, or acts described in the
specification and equivalents thereof.
35 U.S.C. § 112,¶ 6.1
As mentioned above, the principal issue before the Court is whether this
disputed claim limitation is a means-plus-function claim limitation. The Federal
Circuit has explained the methodology a court should use when determining whether
a disputed claim limitation is a means-plus-function claim limitation as follows:
Means-plus-function claim limitations, authorized by 35
U.S.C. § 112, ¶ 6, allow a patentee to draft claim terms as
a means or step for performing a specified function
without the recital of structure, material, or acts in support
thereof. But this flexibility in claim drafting comes at a
price. Such claims are construed to cover only the
structure, materials, or acts described in the specification
as corresponding to the claimed function and equivalents
thereof.
It is well settled that a claim limitation that actually uses
the word ‘means’ invokes a rebuttable presumption that §
112, ¶ 6 applies. And, it is equally understood that a claim
term that does not use ‘means’ will trigger the rebuttable
presumption that § 112, ¶ 6 does not apply. But this
presumption against the application of § 112, ¶ 6 to a claim
term lacking the word ‘means’ can be overcome if a party
can demonstrate that the claim term fails to recite
sufficiently definite structure or else recites function
without reciting sufficient structure for performing that
1

The Leahy-Smith America Invents Act (the “AIA”), Pub. L. No. 112-29, 125 Stat.
284, 296-7, reorganized Section 112, effective September 16, 2012. Section 112,
paragraph 6 was replaced by Section 112(f) for patent applications filed on or after
September 16, 2012. Because the applications resulting in the Patents were filed
before that date, the pre-AIA version of Section 112 applies here. See Media Rights
Techs., Inc. v. Capital One Fin. Corp., 800 F.3d 1366, 1371 n.1 (Fed. Cir. 2015).
7

function. In undertaking this analysis, we ask if the claim
language, read in light of the specification, recites
sufficiently definite structure to avoid § 112, ¶ 6.
Media Rights, 800 F.3d at 1371-72 (internal punctuation and citations omitted). A
claim limitation may fail to recite sufficiently definite structure when it uses a
generic placeholder or “nonce” word, similar to “means,” such as mechanism,
element, device, or module. MIT v. Abacus Software, 462 F.3d 1344, 1354 (Fed. Cir.
2006).
The Court concludes that this disputed claim limitation is not a means-plusfunction claim limitation. Turning first to the disputed claim language, the Court
notes that the disputed claim limitation does not use the term “means.” Accordingly,
there is a presumption that this claim limitation is not a means-plus-function claim
limitation. See Media Rights, 800 F.3d at 1371 (“[I]t is equally understood that a
claim term that does not use ‘means’ will trigger the rebuttable presumption that §
112, ¶ 6 does not apply”).
This presumption that the claim limitation is not means-plus-function can be
overcome in certain circumstances. For example, the presumption can be overcome
where a limitation “fails to recite sufficiently definite structure or else recites
function without reciting sufficient structure for performing that function.” Media
Rights, 800 F.3d at 1372 (internal quotation marks omitted). “[T]o help determine
whether a claim term recites sufficient structure, [the Court] examine[s] whether it

8

has an understood meaning in the art.” Linear Tech. Corp. v. Impala Linear Corp.,
379 F.3d 1311, 1320 (Fed. Cir. 2004). The Federal Circuit has recognized that the
word “‘circuit’ by “itself connotes some structure.” Apex Inc. v. Raritan Computer
Inc., 325 F.3d 1364, 1373 (Fed. Cir. 2004). In addition, “when the structureconnoting term ‘circuit’ is coupled with a description of the circuit’s operation,
sufficient structural meaning generally will be conveyed to persons of ordinary skill
in the art, and § 112, ¶ 6 presumptively will not apply.” Linear Tech. Corp., 379
F.3d at 1320.
Here, the disputed claim limitation uses the term “circuit” and includes a
description of the circuit’s operation. Specifically, the ‘352 Patent uses the adjective
“input,” which modifies the word “circuit,” and it includes the additional descriptive
language “for generating a brake level signal representing the braking force to be
applied to the towed vehicle’s brakes.” These phrases narrow the claim limitation
to specific types of circuits giving the claim limitation a sufficient structure. See id.;
see also Apex Inc., 325 F.3d at 1374 (holding that the claim limitation “interface
circuit” was sufficient structure to avoid being a means-plus-function claim
limitation because the adjective “interface” further defined the type of circuit
claimed). Indeed, when the Federal Circuit has addressed similar “circuit” claim
limitations, it has concluded that those claim limitations were not means-plusfunction claim limitations. See, e.g., Apex Inc., 325 F.3d at 1372; Linear Tech. Corp.,

9

379 F.3d at 1320; Massachusetts Institute of Technology v. Abacus Software, 462
F.3d 1344, 1355 (Fed. Cir. 2006).
Moreover, the ‘352 Patent uses the standard language “means for” when a
means-plus-function claim limitation is desired. For example, in Claim 19, the ‘352
Patent provides that “malfunction monitoring means for monitoring the functioning
of said microcontroller and resetting said microcontroller when a malfunction is
detected.” (‘352 Pat. at col. 42, ll. 52-54, ECF #38-6 at 64, Pg. ID 925; emphasis
added.) The use of the standard “means for” language in Claim 19 (and elsewhere
in the ‘352 Patent) indicates that when the ‘352 Patent intends a means-plus function
limitation, it uses the standard “means for” language. See Karlin Tech., Inc. v.
Surgical Dynamics, Inc., 177 F.3d 968, 972 (Fed. Cir. 1999) (“[D]ifferent words or
phrases used in separate claims are presumed to indicate that the claims have
different meanings and scope”). For all of these reasons, the Court concludes the
presumption has not been overcome.
Hopkins resists this conclusion on two primary grounds. First, Hopkins insists
that the line of the cases the Court relies upon above, including the Linear decision,
are inapposite. According to Hopkins, these cases were decided under a nowoverruled line of authority which held that the absence of the term “means” created
a “strong” presumption against a finding of means-plus-function. See, e.g., Lighting
World, Inc. v. Birchwood Lighting, Inc., 382 F.3d 1354, 1358 (Fed. Cir. 2004)

10

(“[T]he presumption flowing from the absence of the term ‘means’ is a strong one
that is not readily overcome”) (emphasis added). Hopkins says that in 2015, the
Federal Circuit overruled Lighting World and reverted back to the standard
rebuttable-presumption standard that existed before Lighting World. See Williamson
v. Citrix Online, 792 F.3d 1339, 1348 (Fed. Cir. 2015) (en banc). But Linear is a
pre-Lighting World decision that was decided under the same rebuttablepresumption standard that exists today under Williamson. Moreover, and in any
event, there has always been a presumption that the absence of the word ‘means’
creates a rebuttable presumption that means-plus-function does not exist, and the
Court would reach the same result here whether that presumption was “strong” or
simply rebuttable. Finally, in Media Rights – a case decided after Williamson – the
Federal Circuit noted that the term “circuit” does define structure. Media Rights, 800
F.3d at 1371-72.

Thus, even after the Federal Circuit overruled the strong

presumption standard from Lighting World, it still recognizes that the word “circuit”
– which is used in the claim limitation in dispute here – connotes sufficient structure
such that the rebuttable presumption against means-plus-function was not overcome.
Second, Hopkins attempts to avoid the Court’s construction through the
submission of expert testimony from Dr. Horenstein supporting its position that the
disputed claim limitation is a means-plus-function claim limitation. But such expert
testimony is not as persuasive as the intrinsic evidence and supporting case law

11

discussed above. See Phillips, 415 F.3d at 1318 (“[C]onclusory, unsupported
assertions by experts as to the definition of a claim term are not useful to a court.
Similarly, a court should discount any expert testimony that is clearly at odds with
the claim construction mandated by the claims themselves, the written description,
and the prosecution history, in other words, with the written record of the patent”)
(internal quotation marks omitted). Accordingly, for all of the reasons stated above,
the Court holds that “input circuit . . .” is not a means-plus-function claim limitation.
3.

“current sensing circuit . . .” of Claims 1 and 44 of the ‘352 Patent

Hopkins requests that the Court construe the claim limitation “a current
sensing circuit for sensing a level of braking current supplied to the brakes of the
towed vehicle through said power switching circuit, and for generating a current
level signal representing the sensed level of braking current” in Claims 1 and 44 of
the ‘352 Patent.
Claim 1 of the ‘352 Patent, representative of the asserted claims, is reproduced
below with the disputed claim limitation bolded and underlined:
1. A brake controller for controlling the brakes of a towed
vehicle, said brake controller comprising:
an input circuit for generating a brake level signal
representing the braking force to be applied by the towed
vehicle's brakes;
a display circuit including a plurality of indicator lights;
a power switching circuit and adapted for coupling to the
brakes of the towed vehicle and to the power supply of the
12

towing vehicle, for selectively supplying power from the
towing vehicle power supply to the brakes of the towed
vehicle in response to a switching control signal supplied
to a control input terminal;
a current sensing circuit for sensing a level of braking
current supplied to the brakes of the towed vehicle
through said power switching circuit, and for
generating a current level signal representing the
sensed level of braking current; and
a microcontroller coupled to said input circuit, said display
circuit, said current circuit, and to said power switching
circuit, said microcontroller generating and supplying a
switching control signal to said control input terminal of
said power switching circuit thereby causing said power
switching circuit to deliver a braking current to the brakes
of the towed vehicle that is related to the brake level signal
supplied to said microcontroller by said input circuit, said
microcontroller illuminating one or more of said indicator
lights of said display circuit to indicate a relative level of
braking of the towed vehicle brakes and controlling one or
more of said indicator lights to indicate that the towed
vehicle brakes are or are not properly connected to said
power switching circuit.
(‘352 Pat. at col. 39, ll. 41-45, ECF #38-6 at 63, Pg. ID 924; emphasis added.)
Similar to the disputed “input circuit . . .” claim limitation discussed in subsection two above, the disagreement between the parties with respect to this claim
limitation is whether or not it is a means-plus-function claim limitation pursuant to
35 U.S.C. § 112, ¶ 6. Likewise, the parties make generally the same arguments in
support of their proposed claim constructions as they did for the “input circuit . . .”
claim limitation.

13

Hopkins argues that this claim limitation is a means-plus-function claim
limitation. Hopkins argues that the corresponding structure in the specification for
the claim limitation is “a circuit comprising two amplifiers, and a network of
resistors that sense current in the brakes of the towed vehicle and supplies a signal
to a microcontroller having programming that calculates the magnitude of current in
the towed vehicle brakes.” (Hopkins Claim Const. Br. at 48, ECF #47 at 55, Pg. ID
1335.)
Cequent argues that this claim limitation is not a means-plus-function claim
limitation. Cequent also argues that this claim limitation does not need to be
construed because the jury will understand its plain and ordinary meaning. In the
alternative, Cequent argues that this claim limitation could be construed as “a circuit
that senses the level of braking current supplied to the brakes of the towed vehicle
through the power circuit, and for generating a current level signal that represents
the sensed level of braking.” (Cequent Claim Const. Br. at 16, ECF #42 at 19, Pg.
ID 982.)

14

The Court further concludes that the presumption has not been overcome
because the disputed claim limitation has an understood meaning in the art to recite
sufficiently definite structure. As discussed above, the Federal Circuit has held that
the word “circuit” by itself connotes some structure. See, e.g., Apex Inc., 325 F.3d at
1373. The disputed claim language also contains the adjective “current sensing” and
other descriptive language further defining the operation of circuit. This claim
language narrows the claim limitation to specific types of circuits giving the claim
limitation a sufficient structure. See id.; see also Linear Tech. Corp., 379 F.3d at
1320.
Finally, the Court notes as it did above that other claims in the ‘352 Patent use
the standard language “means for” when a means-plus-function claim limitation is
desired. (See, e.g., ‘352 Pat. at col. 42, ll. 52-54, ECF #38-6 at 64, Pg. ID 925.) The
use of standard “means for” language in other claim limitations when a means-plusfunction claim limitation is desired is intrinsic evidence that supports the Court’s
conclusion that the disputed claim limitation – which does not use the standard
“means for” language – is not intended to be a means-plus-function claim limitation.
See Karlin Tech., Inc., supra.
In conclusion, the Court holds that this claim limitation is not a means-plusfunction claim limitation.

16

4.

“gain adjustment circuit . . .” in Claim 44

Hopkins requests that the Court construe the claim limitation “a gain
adjustment circuit coupled to said manual input circuit and to said sensor input
circuit for receiving brake level signals output therefrom that are indicative of a
desired level of braking and for generating a gain-adjusted brake level signal in
response to a brake level signal received from either said manual input circuit or said
sensor input circuit” in Claim 44 of the ‘352 Patent.
Claim 44 of the ‘352 Patent is reproduced below with the disputed claim
limitation bolded and underlined:
44. A brake controller for controlling the brakes of a towed
vehicle, said brake controller comprising:
a brake light circuit adapted for coupling to a brake light
of a towing vehicle for generating an output signal when
the brake light is illuminated as a basis for determining
that the brakes of the towing vehicle are actuated;
a sensor input circuit coupled to said brake light circuit for
sensing the deceleration of the towing vehicle in response
to said output signal from said brake light circuit;
a manual input circuit for receiving input from an operator
of the towing vehicle of a desired braking force of the
towed vehicle's brakes;
a gain adjustment circuit coupled to said manual input
circuit and to said sensor input circuit for receiving
brake level signals output therefrom that are indicative
of a desired level of braking and for generating a gainadjusted brake level signal in response to a brake level

17

signal received from either said manual input circuit
or said sensor input circuit;
a power control circuit adapted for coupling to a power
supply of the towing vehicle for supplying power to the
brakes of the towed vehicle;
a power switching circuit coupled to said power control
circuit and having a brake terminal adapted for coupling
to the brakes of the towed vehicle, for selectively
supplying power from said power control circuit to the
brakes of the towed vehicle in response to a switching
control signal supplied to a control input terminal;
a current sensing circuit for sensing a level of braking
current supplied from said power control circuit to the
brakes of the towed vehicle through said power switching
circuit, and for generating a current level signal
representing the sensed level of braking current;
a display circuit for displaying information to the operator
of the towing vehicle;
a microcontroller coupled to said brake light circuit, said
sensor input circuit, said manual input circuit, said gain
adjustment circuit, said power control circuit, said power
switching circuit, said current sensing circuit, and to said
display circuit, said microcontroller adapted to generate
and supply a switching control signal to said control input
terminal of said power switching circuit thereby causing
said power switching circuit to deliver a braking current to
the brakes of the towed vehicle that is related to the gainadjusted brake level signal supplied to said
microcontroller by said gain adjusting circuit.
(‘352 Pat. at col. 45-46, ll. 57-39, ECF #38-6 at 66, Pg. ID 927; emphasis added.)
Just as with the two disputed claim limitations discussed in sub-sections two
and three above, the disagreement between the parties with this claim limitation is
18

whether or not this claim limitation is a means-plus-function limitation pursuant to
35 U.S.C. § 112, ¶ 6. 2 The parties also make generally the same arguments in
support of their proposed claim constructions as they did for the “input circuit . . .”
and “current sensing circuit . . .” claim limitations.
Hopkins argues that this claim limitation is a means-plus-function claim
limitation.

Hopkins further argues that the corresponding structure in the

specification for the claim limitation is “an analog circuit comprising three resistors,
a capacitor, an amplifier and potentiometer that supplies a variable voltage based
upon the variable resistance of the potentiometer based upon a time constant defined
by the resistors and capacitor that are amplified by the amplifier. The circuit is
coupled to both the manual input circuit and sensor input circuit. The function is to
adjust the gain on a signal from both the manual input circuit and the sensor input
circuit.” (Hopkins Claim Const. Br. at 50-51, ECF #47 at 57-58, Pg. ID 1337-38.)
Cequent argues that this claim limitation is not a means-plus-function claim
limitation. Cequent also argues that this claim limitation does not need to be
construed because the jury will understand its plain and ordinary meaning. In the
alternative, Cequent argues that this claim limitation could be construed as “a circuit

2

Hopkins asserts in its response brief that the parties dispute the meaning of “and”
in this claim limitation; however, in Cequent’s reply brief, it says it agrees with
Hopkins’ proposed meaning of the word “and.” (See Cequent Reply Br. at 13, ECF
#53 at 15, Pg. ID 1756.) Therefore, the meaning of “and” is not in dispute.
19

For generally the same reasons discussed above with respect to the “input circuit . . .”
and “current sensing circuit” claim limitations, the Court concludes that the disputed
claim limitation is not a means-plus-function claim limitation. The Court again
notes that the disputed claim limitation does not use the term “means.” Accordingly,
there is a presumption that this claim limitation is not a means-plus-function claim
limitation. And, as above, the presumption has not been overcome here because the
disputed claim limitation has an understood meaning in the art to recite sufficiently
definite structure. In addition to using the term “circuit,” which connotes structure,
see, e.g., Apex Inc., 325 F.3d at 1373, the disputed claim language also contains the
adjective “gain adjustment” and other descriptive language further defining the
operation of circuit. For example, the claim limitation describes the operation of the
circuit as “generating a gain-adjusted brake level signal in response to a brake level
signal received from either said manual input circuit or said sensor input circuit.”
This claim language narrows the claim limitation to specific types of circuits giving
the claim limitation a sufficient structure. See id.; see also Linear Tech. Corp., 379
F.3d at 1320.
Finally, the Court again notes that the use of standard “means for” language
in other claim limitations when a means-plus-function claim limitation is desired is
intrinsic evidence that supports the Court’s conclusion that the disputed claim

21

limitation – which does not use this standard “means for” language – is not intended
to be a means-plus-function claim limitation. See Karlin Tech., Inc., supra.
In conclusion, the Court holds that this claim limitation is not a means-plusfunction claim limitation.
5.

“said microcontroller varying the duty cycle . . .” in Claim 64

Hopkins requests that the Court construe the claim limitation “said
microcontroller varying the duty cycle of the pulse width modulated control signal
in response to the brake level signal” in Claim 64 of the ‘352 Patent.
Claim 64 of the ‘352 Patent is reproduced below with the disputed claim
limitation bolded and underlined:
64. A brake controller for controlling the brakes of a towed
vehicle, said brake controller comprising:
an input circuit for generating a brake level signal
representing the braking force to be applied by the towed
vehicle's brakes;
a power switching circuit adapted for coupling to the
brakes of the towed vehicle and to the power supply of the
towing vehicle, for selectively supplying power from the
towing vehicle power supply to the brakes of the towed
vehicle in response to a pulse width modulated control
signal supplied to a control input terminal whereby the
braking current supplied to the towed vehicle brakes
corresponds to a duty cycle of the pulse width modulated
control signal; and
a microcontroller coupled to said input circuit and to said
power switching circuit, said microcontroller generating
and supplying the pulse width modulated control signal to
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said control input terminal of said power switching circuit,
said microcontroller varying the duty cycle of the pulse
width modulated control signal in response to the
brake level signal supplied to said microcontroller by said
input circuit to thereby cause said power switching circuit
to deliver a braking current to the brakes of the towed
vehicle that corresponds to the desired level of braking.
(‘352 Pat. at col. 48-49, ll. 64-3, ECF #38-6 at 67-68, Pg. ID 928-29; emphasis
added.)
Hopkins argues that this claim limitation should be construed as “changing
the percentage time the control signal is high based directly upon the variable voltage
produced by the signal axis accelerometer.” (Hopkins Claim Const. Br. at 53, ECF
#47 at 60, Pg. ID 1340.)
Cequent argues that this claim limitation does not need to be construed. In
the alternative, Cequent argues, if the Court believes a construction for this claim
limitation is needed, that this claim limitation should be construed as “the
microcontroller changes a parameter of the pulse width modulated control signal in
response to the brake level signal supplied to the microcontroller.” (Cequent Claim
Const. Br. at 20, ECF #42 at 23, Pg. ID 986.)
In the table below, the Court summarizes these two competing positions and
summarizes the Court’s construction of this disputed claim limitation:

23

construction is based on its previous argument that the claim limitation “input
circuit . . .” should be construed as a means-plus-function claim limitation. If the
claim limitation “input circuit” is interpreted as a means function claim limitation,
Hopkins argues that the specification discloses a single-axis, pendulum-type
accelerometer and that the output of a signal axis accelerometer is necessarily a
variable voltage. Accordingly, Hopkins argues that the claim language should be
limited to the embodiment disclosed in the specification and equivalents thereof
pursuant to 35 U.S.C. § 112, ¶ 6.
The Court rejects Hopkins’ proposed construction because it rests on its
previous argument that the “input circuit . . .” claim language is a means-plusfunction claim limitation. Because the Court has already held that the “input
circuit . . .” is not a means-plus-function claim limitation, it would be improper to
import examples from the written description section of the patent into the claims.
See Phillips, 415 F.3d at 1323 (“[W]e have expressly rejected the contention that if
a patent describes only a single embodiment, the claims of the patent must be
construed as being limited to that embodiment”). Moreover, the Court also holds
that the disputed claim language “in response to the brake level signal” is clear and
would be understandable by a jury. Accordingly, the Court finds that the second
phrase of this disputed claim limitation does not need to be construed at this time.

25

B.

The ‘780 Patent
1.

Background on the ‘780 Patent

The ‘780 Patent is directed to “a new and improved brake control system for
controlling the brakes on a trailer being towed by a towing vehicle.” (‘780 Pat. at
col. 1, ll. 23-25, ECF #38-7 at 4, Pg. ID 935.) More specifically, the ‘780 Patent is
directed to an electronic brake controller that senses inclination and deceleration of
the towing vehicle and compensates trailer braking based on the inclination and
deceleration that was sensed. (See id. at col. 4, ll. 7-25, ECF #38-7 at 5, Pg. ID 936.)
By sensing the inclination, the controller is able to compensate for uphill and
downhill operating conditions by braking the trailer more going downhill and less
when going uphill. (See id.) The trailer brake controller also provides for more
trailer braking when more vehicle deceleration is sensed. (See id.)
2.

“sensing inclination . . .” in Claim 1 of the ‘780 Patent

Hopkins requests that the Court construe the claim limitation “sensing
inclination of one of the towing vehicle and the trailer” in Claim 1 of the ‘780 Patent.
Claim 1 of the ‘780 Patent is reproduced below with the disputed claim
limitation bolded and underlined:
1. A method for controlling brakes on a trailer being towed
by a towing vehicle, comprising:
sensing rate of deceleration of one of the towing vehicle
and the trailer;

26

sensing inclination of one of the towing vehicle and the
trailer;
generating a variable deceleration signal as a function of
said rate of deceleration and a variable inclination signal
as a function of said sensed inclination;
sending a brake amperage output signal to control the
brakes on the trailer; and
continuously proportioning said brake amperage output
signal in accordance with both said deceleration and said
inclination signals.
(Id. at col. 5, ll. 53-67, ECF #38-7 at 6, Pg. ID 937; emphasis added.)
Hopkins argues that this claim limitation should be construed as “[d]etecting
the magnitude of incline of either the towing vehicle or the trailer with respect to the
horizon from a signal that is separate and distinct from a signal carrying deceleration
information, the inclination signal containing no deceleration information and is not
a component of a signal carrying other information, such as deceleration
information.” (Hopkins Claim Const. Br. at 11, ECF #47 at 18, Pg. ID 1298.)
Cequent argues that this claim limitation does not need to be construed. In
the alternative, Cequent argues, if the Court believes a construction for this claim
limitation is needed, that this claim limitation should be construed as “sensing
inclination of either the towing vehicle, the trailer, or both.” (Cequent Claim Const.
Br. at 24, ECF #42 at 27, Pg. ID 990.)

27

The Court concludes that the claim language “sensing inclination of one of
the towing vehicle and the trailer” means sensing the “magnitude” of the inclination
of the towing vehicle, the trailer, or both. Indeed, a key purpose of the invention is
to sense the magnitude of the inclination and then compensate the trailer braking
accordingly. Only by sensing the magnitude of inclination is the controller able to
compensate for the extent of the downhill operating condition by braking the trailer
with the specific amount of force appropriate for the particular condition. (See ‘780
pat. at col. 4, ll. 7-25, ECF #38-7 at 5, Pg. ID 936.)
The written description of the ‘780 Patent also supports the Court’s conclusion.
See Phillips, 415 F.3d at 1317 (“It is therefore entirely appropriate for a court, when
conducting claim construction, to rely heavily on the written description for
guidance as to the meaning of the claims”). The written description then provides
that “[t]he controller [] is programmed so as to only provide a brake amperage output
signal along line [] proportionate to the sensed inclination and rate of deceleration
when the towing vehicle brakes have been engaged or activated.” (‘780 Patent at col.
4, ll. 42-46, ECF #38-7 at 5, Pg. ID 936; emphasis added.) In order for the controller
to provide a signal that is “proportionate to the sensed inclination,” the controller
must have information concerning the magnitude of the inclination. Indeed, the
controller could not “proportion” the output signal if the controller simply had
information indicating the fact that the vehicle was inclined.

29

The text surrounding the disputed claim limitation contains additional
evidence supporting the Court’s conclusion. See ACTV, Inc. v. Walt Disney Co., 346
F.3d 1082, 1088 (Fed. Cir. 2003) (“While certain terms may be at the center of the
claim construction debate, the context of the surrounding words of the claim also
must be considered in determining the ordinary and customary meaning of those
terms”). The claim limitation that immediately follows the disputed claim limitation
provides that “generating a variable deceleration signal as a function of said rate of
deceleration and a variable inclination signal as a function of said sensed inclination.”
(‘780 Patent at col. 5, ll. 59-62, ECF #38-7 at 6, Pg. ID 937.) The invention could
only generate a “variable inclination signal as a function of said sensed inclination”
if it sensed the magnitude of the inclination – otherwise, the signal would not be
“variable.”
The Court further concludes that the additional language proposed by Hopkins
is not needed and would be confusing to a jury. Accordingly, the Court holds that
the claim limitation “sensing inclination of one of the towing vehicle and the trailer”
should be construed to mean “sensing the magnitude of inclination of the towing
vehicle, the trailer, or both.”
3.

“sending a brake amperage output signal” in Claim 1 of the ‘780
Patent

Hopkins requests that the Court construe the claim limitation “sending a brake
amperage output signal” in Claim 1 of the ‘780 Patent.
30

Claim 1 of the ‘780 Patent is reproduced below with the disputed claim
limitation bolded and underlined:
1. A method for controlling brakes on a trailer being towed
by a towing vehicle, comprising:
sensing rate of deceleration of one of the towing vehicle
and the trailer;
sensing inclination of one of the towing vehicle and the
trailer;
generating a variable deceleration signal as a function of
said rate of deceleration and a variable inclination signal
as a function of said sensed inclination;
sending a brake amperage output signal to control the
brakes on the trailer; and
continuously proportioning said brake amperage output
signal in accordance with both said deceleration and said
inclination signals.
(‘780 Pat. at col. 5, ll. 53-67, ECF #38-7 at 6, Pg. ID 937; emphasis added.)
Hopkins argues that this claim limitation should be construed as “supplying a
calculated current amperage, calculated during the continuously proportioning step,
to control the trailer brakes.” (Hopkins Claim Const. Br. at 15, ECF #47 at 22, Pg.
ID 1302.)
Cequent argues that this claim limitation does not need to be construed. In
the alternative, Cequent argues that, if the Court believes a construction for this claim
limitation is needed, this claim limitation should be construed as “sending an

31

measures ‘flow’”) (emphasis added). Moreover, both Hopkins and Cequent appear
to agree that amperage refers to current. (See Cequent Reply Br. at 21, ECF #53 at
23, Pg. ID 1764; see also Hopkins Resp. Br. at 17-18, ECF #47 at 24-25, Pg. ID.
1304-1305.) Thus, because the “ordinary” and “widely accepted” meaning of the
word ‘amperage’ refers to current, the Court need not add a reference to ‘current’ to
the claim limitation. Phillips, 415 F.3d at 1314 (“In some cases, the ordinary
meaning of claim language as understood by a person of ordinary skill in the art may
be readily apparent even to lay judges, and claim construction in such cases involves
little more than the application of the widely accepted meaning of commonly
understood words”).
As to Hopkins’ proposal to construe this claim limitation to require that the
output signal must be “calculated” and that the calculation occur “during the
continuously proportioning step,” the Court concludes that it would be improper to
narrow the claim language as Hopkins proposes. Claim 1 of the ‘780 Patent does
not contain a “calculation” step. It would therefore be improper for the Court to
import limitations from the written description into the claim. See Phillips, 415 F.3d
at 1323 (“[W]e have expressly rejected the contention that if a patent describes only
a single embodiment, the claims of the patent must be construed as being limited to
that embodiment”).

33

In conclusion, the Court holds that the claim limitation does not need to be
construed at this time.
4.

“continuously proportioning . . .” in Claim 1 of the ‘780 Patent

Hopkins requests that the Court construe the claim limitation “continuously
proportioning said brake amperage output signal in accordance with both said
deceleration and said inclination signals” in Claim 1 of the ‘780 Patent.
Claim 1 of the ‘780 Patent is reproduced below with the disputed claim
limitation bolded and underlined:
1. A method for controlling brakes on a trailer being
towed by a towing vehicle, comprising:
sensing rate of deceleration of one of the towing
vehicle and the trailer;
sensing inclination of one of the towing vehicle and the
trailer;
generating a variable deceleration signal as a function
of said rate of deceleration and a variable inclination
signal as a function of said sensed inclination;
sending a brake amperage output signal to control the
brakes on the trailer; and
continuously proportioning said brake amperage
output signal in accordance with both said
deceleration and said inclination signals.
(‘780 Pat. at col. 5, ll. 53-67, ECF #38-7 at 6, Pg. ID 937; emphasis added.)

34

As to the first issue, Hopkins argues that the Court should construe the word
“continuously” to mean “the entire time the claimed deceleration and inclination
signals are being received.” (Hopkins Supp. Claim Constr. Br. at 10, ECF #58 at 11,
Pg. ID 2104.) In contrast, Cequent contends that the word “continuously” only
means that the brake amperage output signal is adjusted repeatedly or without
interruption, but it does not require that the adjusting of the brake signal be the entire
time that braking is desired or the entire time that the deceleration and inclination
signals are received. (See Cequent Supp. Claim Const. Br. at 1-6, ECF #57 at 2-7,
Pg. ID 2055-60.)
The Court concludes that the word “continuously” in the context of the ‘780
Patent means “adjusting the amperage output signal sent to the brakes without
interruption the entire time that deceleration and inclination signals are received.”
This construction of “continuously” is most consistent with its ordinary
meeting. The word “continuously” describes events “that are uninterrupted in time,
substance,

extent;

ceaseless.”

See

Writing

http://writingexplained.org/continually-vs-continuously-difference.

Explained,
See

also

Chicago Mercantile Exch., Inc. v. Technology Research Group, LLC, 789 F.
Supp.2d 986, 993 (N.D. Ill. 2011) (“With the aid of these [dictionary] definitions,
the Court concludes that the word “continuously” in this context means ‘without
interruption or break for a period of time’”); Ronald A. Smith & Assocs. v.

36

Hutchinson Tech. Inc., 2002 WL 34691122, *6 (N.D. Cal. 2002) (“Thus, the plain
and ordinary meaning of ‘continuously’ is ‘without interruption’”); Curtiss-Wright
Flow Control Corp. v. Velan, Inc., 2006 WL 62092221, *15 (W.D. Tex. 2006) (“The
term ‘continuously’ commonly means constant or uninterrupted”).

This

construction is also consistent with the written description of the ‘780 Patent which
provides that the invention provides the desired amount of braking “at all times” and
makes “real time” adjustments for inclination. (‘780 pat. at col. 3, ll. 7-11 and col. 4
ll. 22-25, ECF #38-7 at 5, Pg. ID 936; emphasis added.)
Cequent insists that “continuously” in this context does not mean the entire
time trailer baking is desired, but need only be continuous when the “brake amperage
output signal is adjusted.” (Cequent Supp. Br. at 1, ECF #57 at 2, Pg. ID 2055.) But
this construction allows for a short gap between the time the brakes are engaged and
when the braking output signal is adjusted. Such a gap is not consistent with the
ordinary understanding of the word “continuously.”
As to the second issue, whether this claim limitation should be construed to
require a “calculating” step as Hopkins proposes – specifically “calculating a
continuous amperage of the output signal required to control the brakes based upon
both the deceleration and inclination signals” – Hopkins argues that the calculation
must occur in order to proportion the brake output signal. In response, Cequent
maintains that the claim does not require a calculating step and such a step should

37

not be read into the claim. The Court concludes that the claim language does not set
forth a calculation step. Accordingly, the Court will not construe the claim language
to require a “calculation” step at this time.
In conclusion, the Court construes the “continuously proportioning said brake
amperage output signal in accordance with both said deceleration and said
inclination signals” to mean “adjusting the amperage output signal sent to the brakes
without interruption the entire time that deceleration and inclination signals are
received.”
C.

The ‘993 Patent
1.

Background on the ‘993 Patent

The ‘993 Patent is directed inter alia to an electronic trailer brake controller
that eliminates the need to manually “level” the brake control unit when the brake
control unit is initially mounted and installed in the vehicle.

Prior art brake

controllers typically required a vehicle operator to “set or adjust, by mechanical
means, a reference level of the accelerometer[,] when the brake control unit was
initially mounted or changed to a different mounting orientation.” (‘993 Pat. at col.
1 ll. 33-37, ECF #38-5 at 9, Pg. ID 856.)
2.

“brake control signal” in Claim 1 of the ‘993 Patent

Hopkins requests that the Court construe the claim limitation “brake control
signal” in Claim 1 of the ‘993 Patent.

38

Claim 1 of the ‘993 Patent is reproduced below with the disputed claim
limitation bolded and underlined:
1. A brake control unit for providing a brake output signal
to a brake load of a towed vehicle, comprising:
a processor;
an accelerometer coupled to the processor, the
accelerometer providing a brake control signal to the
processor, wherein the processor is programmed to cause
an appropriate brake output signal to be provided to the
brake load responsive to the brake control signal;
and a memory subsystem coupled to the processor, the
memory subsystem storing processor executable code
which causes the processor to automatically acquire an
operating point of the brake control signal when the brake
control unit is mounted within a range of operating
positions.
(Id. at col. 10, ll. 5-23, ECF #38-5 at 13, Pg. ID 860; emphasis added.)
Hopkins argues that this claim limitation should be construed as “an
instantaneous voltage developed by the single axis accelerometer directly
representing the magnitude of deceleration in the direction of travel.” (Hopkins
Claim Const. Br. at 26, ECF #47 at 34, Pg. ID 1314.)
Cequent argues that this claim limitation does not need to be construed. In
the alternative, Cequent argues, if the Court believes a construction for this claim
limitation is needed, that this claim limitation should be construed as “the signal that
the accelerometer provides.” (Cequent Claim Const. Br. at 34, ECF #42 at 37, Pg.

39

words.” Phillips, 415 F.3d at 1314. This is one such claim limitation. Moreover, the
claim language in dispute was intentionally written to be broad. It would be
improper to import features of example embodiments from the written description
into the claim without a clear disavowal or disclaimer of broad claim scope. See id.
at 1323 (“[A]lthough the specification often describes very specific embodiments of
the invention, we have repeatedly warned against confining the claims to those
embodiments”).
3.

“automatically acquiring an operating point” in Claim 1 of the ‘993
Patent

Hopkins requests that the Court construe the claim limitation “automatically
acquire an operating point of the brake control signal” in Claim 1 of the ‘993 Patent.
Claim 1 of the ‘993 Patent is reproduced below with the disputed claim
limitation bolded and underlined:
1. A brake control unit for providing a brake output signal
to a brake load of a towed vehicle, comprising:
a processor;
an accelerometer coupled to the processor, the
accelerometer providing a brake control signal to the
processor, wherein the processor is programmed to cause
an appropriate brake output signal to be provided to the
brake load responsive to the brake control signal;
and a memory subsystem coupled to the processor, the
memory subsystem storing processor executable code
which causes the processor to automatically acquire an
operating point of the brake control signal when the
41

brake control unit is mounted within a range of operating
positions.
(‘993 Pat. at col.10, ll. 5-23, ECF #38-5 at 13, Pg. ID 860; emphasis added.)
Hopkins argues that this claim limitation should be construed as “the
microprocessor determines the reference level voltage of the brake control signal
based on one or more voltage values obtained from a time other than during braking.”
(Hopkins Claim Const. Br. at 29, ECF #47 at 36, Pg. ID 1316.)
Cequent argues that this claim limitation does not need to be construed. In
the alternative, Cequent argues, if the Court believes a construction for this claim
limitation is needed, that this claim limitation should be construed as “a value
representing accelerometer output during a period other than during a braking event.”
(Cequent Claim Const. Br. at 37, ECF #42 at 40, Pg. ID 1003.)

42

operating point of the brake control signal” to mean:
[O]btain by processor operation an operating point of the
signal provided by the accelerometer, where ‘operating
point’ is a value representing the level or magnitude of the
accelerometer output at a time other than during a braking
event. “Acquir[ing] an operating point” encompasses
reading a signal value of the accelerometer output as well
as calculating or otherwise determining a value based on
multiple readings of the accelerometer output.
(IPR Final Written Decision ‘993 Pat. at 17-18, Hopkins Mfg. Corp. v. Cequent
Performance Prods., Inc., Case IPR2015-00609.)
The Court concludes that the USPTO’s claim construction of the ‘993 Patent
in the IPR Final Written Decision is well reasoned.

Although the Court

acknowledges that the USPTO construes claim limitations under a “broadest
reasonable construction” standard, while district courts apply a plain and ordinary
meaning standard, the Court does not feel that the different standards lead to a
different result for this particular claim limitation. See Cuozzo Speed Techs. LLC v.
Lee, 136 S. Ct. 2131, 2144-46 (2016).

Accordingly, the Court adopts the

construction set forth by the USPTO in the IPR Final Written Decision.
4.

“mounted within a range of operating positions” in Claim 1 of the
‘993 Patent

Hopkins requests that the Court construe the claim limitation “when the brake
control unit is mounted within a range of operating positions” in Claim 1 of the ‘993
Patent.

44

Claim 1 of the ‘993 Patent is reproduced below with the disputed claim
limitation bolded and underlined:
1. A brake control unit for providing a brake output signal
to a brake load of a towed vehicle, comprising:
a processor;
an accelerometer coupled to the processor, the
accelerometer providing a brake control signal to the
processor, wherein the processor is programmed to cause
an appropriate brake output signal to be provided to the
brake load responsive to the brake control signal;
and a memory subsystem coupled to the processor, the
memory subsystem storing processor executable code
which causes the processor to automatically acquire an
operating point of the brake control signal when the brake
control unit is mounted within a range of operating
positions.
(‘993 Pat. at col. 10, ll. 5-23, ECF #38-5 at 13, Pg. ID 860; emphasis added.)
The principal dispute between the parties is whether the claim language
requires that there be at least some mounting positions in which the brake control
unit will not properly operate.
Hopkins argues that this claim limitation should be construed to mean that
“the brake control unit must be installed within a limited range of orientations in the
direction of travel.” (Hopkins Claim Const. Br. at 33, ECF #47 at 40, Pg. ID 1320.)
At oral argument, Hopkins agreed that the wording “a limited range” in its proposed
construction could be replaced with “a relatively wide but not unlimited range.”

45

The Court concludes that the claim language requires that there be at least
some mounting positions in which the brake control unit will not properly operate.
Specifically, the claim language states that the processor automatically acquires an
operating point of the brake control signal “when the brake control unit is mounted
within a range of operating positions.” (‘993 Patent at col. 10, ll. 6-22, ECF #38-5
at 13, Pg. ID 860.) By limiting the scope of the claim to “when the brake control
unit is mounted within a range of operating positions[,]” the claim language
contemplates that there are mounting positions in which the brake control unit will
not properly operate. (Id.) In other words, the range of operating positions is not
unlimited. The Court’s conclusion is supported by the written description section of
the ‘993 Patent which states that the brake control unit has a “relatively wide”
mounting range. (Id. at col. 4 ll. 14-20, ECF #38-5 at 11, Pg. ID 858.) By stating
that the brake control unit has a “relatively wide” mounting range, the plain language
of the ‘993 Patent implies that the range is not unlimited and that there are at least
some mounting positions in which the brake control unit will not properly operate.

47

III
The Court construes the disputed claim limitations as set forth above. The
Court reserves the right to modify its claim constructions as the infringement and
validity issues of the Patents become known. See Lava Trading, Inc. v. Sonic
Trading Mgmt., LLC, 445 F.3d 1348, 1350 (Fed. Cir. 2006).
IT IS SO ORDERED.
s/Matthew F. Leitman
MATTHEW F. LEITMAN
UNITED STATES DISTRICT JUDGE
Dated: January 26, 2017

I hereby certify that a copy of the foregoing document was served upon the
parties and/or counsel of record on January 26, 2017, by electronic means and/or
ordinary mail.
s/Holly A. Monda
Case Manager
[phone]

48