Federal Circuit Infers Disavowal, Limiting Scope of Chamberlain Patent

Federal Circuit Infers Disavowal, Limiting Scope of Chamberlain Patent

Jan 02, 2020

Client Alert

Brownstein Client Alert, January 2, 2020

The Federal Circuit has issued another opinion arising from the patent conflict between The Chamberlain Group and Techtronic Industries1—and, once again, a patent owned by Chamberlain suffered a major blow. In Techtronic Industries v. International Trade Commission (“Techtronic”), the Federal Circuit limited the scope of Chamberlain’s claims in U.S. Patent No. 7,161,3192 (the “’319 patent”) based on the doctrine of claim scope disavowal.3

Generally, a term in a patent claim is interpreted using its ordinary and customary meaning, as understood by a person of ordinary skill in the art.4 However, if the specification of the patent describes a certain feature of the invention as “important, essential, or critical to the invention,”5 the claims may be construed as requiring that feature even if the feature is not affirmatively recited in the claims.6 As a result, the patentee may be considered to have disavowed any claim scope that falls outside of the essential subject matter.


The ’319 patent describes a garage door opening system having a wall-mounted console that includes a microcontroller for controlling an overhead motor drive unit.7 The written description of the ’319 patent also describes an infrared detector located within the wall-mounted console, though such a detector was not recited in the claims at issue in the ’319 patent.8

Alleging violations of Section 337 of the Tariff Act of 1930,9 Chamberlain asserted the ’319 patent against certain garage door openers manufactured and sold by Techtronic.10 While the garage door openers sold by Techtronic did include a wall-mounted console able to control an overhead motor drive unit, Techtronic’s consoles did not include an infrared detector.

In a final determination, the International Trade Commission (“ITC”) concluded that Techtronic’s garage door openers violated Section 337 and infringed on the claims of the ’319 patent.11 On the question of disavowal, the ITC determined that all features described as important in the written description need not be required in the ’319 patent claims.12 The ITC distinguished the result from prior cases “on the basis that the prosecution history of the ’319 patent lacked ‘[a] clear prosecution history disclaimer.’”13 Thus, the ITC interpreted the “wall console” under its ordinary meaning—as a console installed on a wall and with or without passive infrared detectors.14

Techtronic appealed the ITC’s final determination to the Federal Circuit.

The Federal Circuit’s Decision

On appeal from the ITC’s final determination, the Federal Circuit considered the proper scope of the claimed wall console. Overturning the ITC, the Federal Circuit concluded that Chamberlain disavowed wall consoles that did not include a passive infrared detector.15

Underpinning the Federal Circuit’s holding was a finding that the ’319 patent specification consistently described the garage door opening system as including an infrared detector located in a wall console. The Federal Circuit paid particular attention to sections of the specification describing the disclosed invention as addressing a particular problem in the garage door technology field.16 As characterized by the Federal Circuit, the ’319 patent disparaged previous garage door openers that included a passive infrared detector in the overhead motor drive unit and, as a solution, described an improved system that requires a passive infrared sensor located within the wall console.17

The Federal Circuit further expressed that “the entire specification focuses on enabling placement of the passive infrared detector in the wall console, which is both responsive to the prior art deficiency the ’319 patent identifies and repeatedly set forth as the objective of the invention . . . [and] [t]hus, the ’319 patent disavows locating the detector elsewhere, even without an express concession to that effect.”18

Ultimately, the Federal Circuit overturned the ITC’s claim construction order and held that the term “wall console” is properly construed as a “wall-mounted control unit including a passive infrared detector” resulting in a finding of non-infringement of the ’319 patent.19


The Federal Circuit has previously held that there is no requirement that a disavowal be explicit.20 Generally, disavowal is found as a result of an applicant’s intentional traversal of known prior art during prosecution. In previous cases relating to disavowal, the Federal Circuit relied more heavily on statements made within the patent prosecution history. 21 However, the Federal Circuit in Techtronic seemed to take this a step further by inferring that a feature is essential based exclusively on the specification.

The holding in Techtronic may be relevant for newly drafted cases that rely on a limited set of examples and a narrowly tailored problem statement. The holding may be particularly relevant for continuations with claims that have been broadened to extend beyond the problem stated in the original description.

It is worth noting that the parent application of the patent in Techtronic did include features related to the presence and location of a passive infrared detector within its claims.22 The continuation ’319 patent omitted these features in an attempt to broaden the scope of the claims and expand the property of the patent—a relatively common practice, particularly if a parent application is allowed with few or no prior art rejections. While continuation practice can be an effective way to expand patent property to target a competitor or to cover current products, Techtronic highlights the importance of having a comprehensive specification that includes multiple varying examples and an expansive view of the problem solved by the described invention.

1 See Techtronic Indus. Co. v. Int’l Trade Comm’n, No. 2018-2191, slip op. (Fed. Cir. Dec. 12, 2019).

2 U.S. Patent No. 7,161,319 (issued Jan. 9, 2007) (The Federal Circuit considered claim 1 to be the representative claim.) (hereafter ’319 Patent).

3 Techtronic Indus. Co., No. 2018-2191, at 14.

4 Phillips v. AWH Corp., 415 F.3d 1303, 1313 (Fed. Cir. 2005) (en banc).

5 Blackbird Tech LLC v. ELB Elecs., Inc., 895 F.3d 1374, 1377–78 (Fed. Cir. 2018).

6 See SciMed Life Sys., Inc. v. Adv. Cardiovascular Sys., Inc., 242 F.3d 1337, 1343–44 (Fed. Cir. 2001).

7 See ’319 Patent, supra note 2.

8 Claim 1 reads:

An improved garage door opener comprising a motor drive unit for opening and closing a garage door, said motor drive unit having a microcontroller and a wall console, said wall console having

a microcontroller, said microcontroller of said motor drive unit being connected to the microcontroller of the wall console by means of a digital data bus. Id.

9 Codified at 19 U.S.C. § 1337 (2018).

10 Including garage door openers sold under the “Ryobi” brand name. See Order No. 13, Certain Access Control Systems and Components Thereof, Inv. No. 337-TA-1016, slip op. (Jan. 26, 2017) (hereafter ALJ Opinion).

11 Techtronic Indus. Co. v. Int’l Trade Comm’n, No. 2018-2191, slip op. at 2 (Fed. Cir. Dec. 12, 2019).

12 Id. at 6.

13 Id. (quoting Certain Access Control Systems and Components Thereof, Inv. No. 337-TA-1016, USITC Pub. 4957, 2017 WL 11198844 (May 5, 2017), at 12).

14 Certain Access Control Systems and Components Thereof, Inv. No. 337-TA-1016, USITC Pub. 4957, 2017 WL 11198844 (May 5, 2017), at 9–12.

15 Techtronic Indus. Co. v. Int’l Trade Comm’n, No. 2018-2191, slip op. at 14 (Fed. Cir. Dec. 12, 2019).

16 U.S. Patent No. 7,161,319 (issued Jan. 9, 2007) at Cols. 1–2.

17 Techtronic Indus. Co., No. 2018-2191, slip op. at 10 (“The ’319 patent disavows coverage of wall consoles lacking a passive infrared detector because the specification, in each of its sections, discloses as the invention a garage door opener improved by moving the passive infrared detector from the overhead motor drive unit to the wall unit.”).

18 Id. at 13.

19 Id.

20 See Trs. of Columbia Univ. v. Symantec Corp., 811 F.3d 1359, 1363 (Fed. Cir. 2016) (“Our case law does not require explicit redefinition or disavowal.”).

21 Poly-America, L.P. v. API Indus., Inc., 839 F.3d 1131 (Fed. Cir. 2016).

22 See U.S. Patent No. 6,737,968 (issued May 18, 2004).


This document is intended to provide you with general information regarding on the Federal Circuit's ruling in Techtronic Industries v. International Trade Commission. The contents of this document are not intended to provide specific legal advice. If you have any questions about the contents of this document or if you need legal advice as to an issue, please contact the attorneys listed or your regular Brownstein Hyatt Farber Schreck, LLP attorney. This communication may be considered advertising in some jurisdictions.

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