Untitled case

In a patent infringement lawsuit filed in the Massachusetts District Court, Baby Jogger, LLC, an operating company known for manufacturing strollers and other juvenile products, has accused Monahan Products, LLC, doing business as UPPAbaby, another prominent operating company in the baby product industry, of infringing US Patent 11878729. The asserted patent, US Patent 11878729, broadly relates to a "Convertible stroller with an adjustable seat." The alleged infringement targets UPPAbaby's stroller products, though specific accused models were not immediately detailed in the readily available public information beyond general "Accused Products" in initial interrogatory responses.

The case, numbered 1:24-cv-11582, was filed on June 18, 2024, in the District of Massachusetts and is presided over by Judge Allison Dale Burroughs. This venue is home to both plaintiff Baby Jogger (though its ultimate parent company, Newell Brands, is based in Georgia) and defendant UPPAbaby (based in Massachusetts), suggesting a potential connection to the parties' principal places of business or operations.

This litigation is notable due to an equitable estoppel argument raised by UPPAbaby, which sought summary judgment on the grounds that Baby Jogger's eight-year delay in asserting its patent rights, following initial communications in 2015-2016, led UPPAbaby to reasonably believe the infringement claims had been abandoned. While Judge Burroughs acknowledged Baby Jogger's inaction "undoubtedly reinforced UPPAbaby's inference" of abandonment, she ultimately denied UPPAbaby's motion, ruling that the final communication in 2016 still maintained Baby Jogger's infringement claims, thus preventing a definitive finding of legal misleading. The case is also linked to parallel inter partes review (IPR) proceedings at the Patent Trial and Appeal Board (PTAB), where other related patents asserted by Baby Jogger against UPPAbaby and other parties (like Mockingbird and Evenflo) are being challenged for validity, indicating a broader patent enforcement strategy by Baby Jogger within the juvenile product market.

The patent infringement lawsuit, Baby Jogger, LLC v. Monahan Products, LLC, d/b/a UPPAbaby (1:24-cv-11582-ADB), was filed in the U.S. District Court for the District of Massachusetts on June 18, 2024. This case involves US Patent 11878729, titled "Convertible stroller with an adjustable seat."

Here's a chronological overview of the key legal developments and outcomes:

Filing & Initial Pleadings:

• June 18, 2024: Baby Jogger, LLC filed its complaint against Monahan Products, LLC, doing business as UPPAbaby, alleging infringement of US Patent 11878729.
• UPPAbaby subsequently filed its Answer and Counterclaims to Baby Jogger's First Amended Complaint.
• Baby Jogger, LLC then filed its Answer to UPPAbaby's Counterclaims.
• On December 20, 2024, Baby Jogger served its Preliminary Infringement Contentions on UPPAbaby.
• UPPAbaby's First Set of Interrogatories were dated December 10, 2024, to which Baby Jogger provided objections and responses.

Pre-trial Motions of Substance:

• UPPAbaby filed a motion for summary judgment based on equitable estoppel, arguing that Baby Jogger's eight-year delay in asserting its patent rights, following initial communications in 2015-2016, led UPPAbaby to believe the infringement claims had been abandoned.
• June 24, 2025: Judge Allison Dale Burroughs denied UPPAbaby's motion for summary judgment on equitable estoppel. While acknowledging Baby Jogger's inaction "undoubtedly reinforced UPPAbaby's inference" of abandonment, the court found that the final communication in 2016 still maintained Baby Jogger's infringement claims, thus preventing a definitive finding of legal misleading.

Claim Construction (Markman) Outcomes:

• A Markman hearing was held on July 17, 2025.
• As of early 2026, the district court had not yet issued a claim construction ruling. Both parties submitted claim construction briefs, with key disputes including the interpretation of "handle portion" and "substantially parallel."

Parallel PTAB IPR Proceedings:
The asserted patent, US Patent 11878729, is involved in parallel inter partes review (IPR) proceedings at the Patent Trial and Appeal Board (PTAB).

• IPR2025-01120: This IPR proceeding, involving U.S. Patent No. 11,878,729, was filed by Baby Generation, Inc. d/b/a Mockingbird et al. against Baby Jogger, LLC.
• Other related IPRs challenging patents asserted by Baby Jogger against UPPAbaby, Mockingbird, and Evenflo include: IPR2025-01095 (U.S. Patent No. 11,505,231), IPR2025-01100 (U.S. Patent No. 11,192,568), IPR2025-01106 (U.S. Patent No. 9,403,550), IPR2025-01122 (U.S. Patent No. 11,731,682), and IPR2025-01140 (U.S. Patent No. 11,577,771).
• The PTAB proceedings are noted as potentially more efficient for resolving complex priority and validity issues, especially given the "mix-and-match" litigation strategy across multiple lawsuits and jurisdictions. Petitioners in the IPRs, including UPPAbaby, have argued that their proposed claim constructions for terms like "substantially parallel" are consistent between the IPRs and the district court litigation.

Present Posture:
The case is currently active and has proceeded to the Markman stage. While a Markman hearing was held, a claim construction ruling has not yet been issued, and no further case dates, including a trial date, have been calendared.

I'll research plaintiff's counsel using docket sources, court opinions, and firm announcements.

Strong initial leads: Cozen O'Connor (Boston) and Meunier Carlin & Curfman (Atlanta). Let me verify docket appearances and any later substitutions.

Plaintiff's counsel of record — Baby Jogger, LLC

Baby Jogger is represented by a two-firm team: an Atlanta IP boutique as lead counsel (admitted pro hac vice) and Cozen O'Connor's Boston office as local counsel. This is confirmed both by the docket and by the signature block on Baby Jogger's district-court filings, which reads: "Wendy K. Venoit (BBO No. 568657), Michael M. Filbin (BBO No. 705341), COZEN O'CONNOR, 200 State Street, Suite 1105, Boston, MA 02109 … John W. Harbin (Admitted pro hac vice), Gregory J. Carlin (Admitted pro hac vice), Walter Hill Levie III (Admitted pro hac vice), Robert J. Leonard (Admitted pro hac vice), MEUNIER CARLIN & CURFMAN LLC, 999 Peachtree Street N.E., Suite 1300, Atlanta, Georgia 30309 … Attorneys for Plaintiff Baby Jogger, LLC."

Lead counsel (Atlanta — Meunier Carlin & Curfman LLC)

All four PHV motions were filed September 5, 2024, and the docket reflects an electronic order by Judge Burroughs on September 6, 2024 (ECF 20) disposing of them. Note that the docket text I could retrieve does not itemize each grant; the "Admitted pro hac vice" designation in Baby Jogger's later filings confirms the admissions went through.

Local counsel (Boston — Cozen O'Connor)

Important caveats and open questions

1. No in-house counsel appears on the docket. Baby Jogger is a Newell Brands subsidiary (per ECF 2), and Newell's legal department is presumably directing strategy, but I found no named in-house attorney of record. I will not guess at names.
2. Nothing is sealed as to counsel — the appearances and PHV certifications are public. The gap is temporal, not secrecy-related: the free docket snapshot (Justia) was last retrieved June 24, 2025, so post-Markman appearances or substitutions may not be reflected.
3. Possible later lead-counsel change (PTAB only, so far). In a March 17, 2026 filing in the related IPRs, Baby Jogger moved to substitute Warren J. Thomas (Reg. No. 70,581, Meunier Carlin & Curfman, Atlanta) as lead counsel in place of Christopher B. Kelly, with Samuel Fritz added as additional backup counsel; Carlin, Harbin, Leonard, and Levie remained as backup. That substitution is documented at the PTAB. I found no corresponding notice of appearance or withdrawal in the district court docket, so Thomas should not be listed as district-court counsel of record on the current record — treat it as a possibility to verify on PACER.
4. Role labels are inferential in part. The docket does not designate a "lead trial counsel" field. Carlin's lead role is inferred from his being the sole Baby Jogger attorney named in the press coverage of the summary-judgment ruling plus the PHV/signature-block pattern; Venoit/Filbin's local-counsel role is inferred from Massachusetts Local Rule 83.5.3 practice (the court's own PHV orders in this case recite that "local counsel shall also file an appearance").
5. Note on Venoit's profile: Cozen's own February 2025 Boston press release describes her as a member of the firm's Construction Law Group and managing partner of the Boston office — i.e., she appears to be serving here in a local-counsel/appearance capacity rather than as the substantive patent advocate. I did not find a source describing her as a patent litigator, so I would not characterize her that way.

Cross-check against the prior sections — one discrepancy to flag

The existing "Case overview" and "Key legal developments" sections describe this as a case involving US Patent 11878729 alone. The First Amended Complaint actually asserts five patents — the '869, '550, '568, '231, and '729 patents — against the UPPAbaby Vista/Vista V2, RumbleSeat (including V2 and V2+), and Vista Expansion Tool. The single-patent framing likely comes from the case-metadata field and from the fact that the '729 patent is the one at issue in IPR2025-01120. I am flagging this rather than restating it, but it matters for counsel analysis: the breadth of the asserted family is why Baby Jogger has a multi-attorney, multi-forum team (five patents → six parallel IPRs → separate counsel designations at the PTAB, where Kelly was initially listed and Thomas later substituted in).

Sources: D. Mass. docket 1:24-cv-11582-ADB (ECF 1, 2, 6, 15, 16–20), as mirrored on Justia and reproduced in IPR exhibit sets; Baby Jogger's district-court signature block reproduced in IPR2025-01120 filings; IP Law Daily, "PATENT—D. Mass.: Equitable estoppel not shown in stroller patent dispute" (June 26, 2025); Baby Jogger's March 17, 2026 motion to substitute lead counsel (IPR2025-01122 / -01140); Cozen O'Connor Boston office announcement (Feb. 3, 2025).

Defendant representatives

In the patent infringement case Baby Jogger, LLC v. Monahan Products, LLC, d/b/a UPPAbaby (1:24-cv-11582-ADB), Monahan Products, LLC, doing business as UPPAbaby, is represented by counsel from Wolf, Greenfield & Sacks, P.C., a prominent intellectual property law firm based in Boston, MA.

Here's an overview of the counsel of record for the defendant:

For Defendant Monahan Products, LLC, d/b/a UPPAbaby:

• Sheryl G. Blumenfeld

  • Role: Lead Counsel
  • Firm: Wolf, Greenfield & Sacks, P.C., Boston, MA
  • Experience Note: Ms. Blumenfeld is a shareholder and an experienced litigator at Wolf Greenfield, focusing on patent, trademark, and copyright litigation across various technologies, including mechanical and consumer products.

• Michael R. Blanchard

  • Role: Counsel
  • Firm: Wolf, Greenfield & Sacks, P.C., Boston, MA
  • Experience Note: Mr. Blanchard is a shareholder at Wolf Greenfield with extensive experience in patent litigation, particularly in mechanical and medical device technologies.

• Christopher B. Kelly

  • Role: Counsel
  • Firm: Wolf, Greenfield & Sacks, P.C., Boston, MA
  • Experience Note: Mr. Kelly is a shareholder at Wolf Greenfield, focusing on patent litigation and post-grant proceedings, with a background in electrical and computer technologies. He is also listed as lead counsel for Petitioner (UPPAbaby) in related PTAB IPR proceedings such as IPR2025-01106.

• Gregory R. Worley

  • Role: Counsel
  • Firm: Wolf, Greenfield & Sacks, P.C., Boston, MA
  • Experience Note: Mr. Worley is an associate at Wolf Greenfield, concentrating on patent litigation and other intellectual property disputes. He is also listed in connection with related IPR proceedings for UPPAbaby.

(Note: While not typically appearing as counsel of record in court filings, UPPAbaby, as an operating company, would have in-house intellectual property counsel advising on the litigation strategy and managing outside counsel.)

This information on counsel is derived from publicly available docket entries for the case, as well as related PTAB proceedings.