By Jessie Hess*, Christian Roberts, and Matthew Johnson –
The Patent Trial and Appeal Board (PTAB) denied institution of an inter partes review (IPR) brought by Par-Kan Company, LLC against Unverferth Manufacturing Company regarding U.S. Patent No. 8,967,940 (“the ‘940 patent”). Par-Kan Co., LLC v. Unverferth Mfg. Co., IPR2024-01426, Paper 10 (P.T.A.B. Mar. 19, 2025). The PTAB found the Patent Owner had successfully established a reduction to practice antedating Petitioner’s references by relying on inventor testimony along with corroborating independent evidence.
The ’940 Patent, titled “Seed Carrier with Pivoting Conveyor,” was directed to agriculture seed carrying and collection equipment. The Petitioner challenged claims 16-23 of the ‘940 patent on obviousness grounds and relied on (among others) two prior art references: i) a August 13, 2006, Morris “7000 Series Air Cart” operator’s manual and ii) a March 14, 2006, snapshot of a Hiniker Company webpage describing a model 4800 seed tender.
The Patent Owner’s preliminary response aimed to eliminate the two key references by demonstrating that the invention was reduced to practice before the publication dates of either the Morris or Hiniker references. To support this argument, the Patent Owner primarily relied on testimony from the inventor and the inventor’s assistant, asserting that the invention claimed in the ’940 Patent was made before both of the Petitioner’s references. In addition, the Patent Owner submitted the following independent evidence to corroborate this claim:
- Photographs, marketing brochures, and a third-party media report showing a prototype publicly displayed at the National Farm Machinery Show in Louisville, Kentucky, on February 15–18, 2006;
- Internal photographs dated February 28, 2006, depicting the same prototype coated with seed dust, evidencing successful operation; and
- Shipping records and field-test photographs proving additional prototypes were in use on farms in Michigan and Illinois by mid-May 2006.
The PTAB explained that “[i]n order to establish an actual reduction to practice, an inventor’s testimony must be corroborated by independent evidence. [A] ‘rule of reason’ analysis is applied to determine whether an inventor’s testimony regarding reduction to practice has been sufficiently corroborated.” Cooper v. Goldfarb, 154 F.3d 1321, 1330 (Fed. Cir. 1998). Applying this standard, the PTAB found that the inventor and his assistant’s testimony taken with the independent evidence collectively established that the prototype embodied every limitation of claims 16–22 and worked for its intended purpose before the publication date of Petitioner’s references.
The PTAB rejected Petitioner’s argument that the prototype did not work for its intended purpose as evidenced by prosecution testimony. Specifically, the Petitioner cited the assistant’s prosecution testimony that “the seed tender prototype units were not operating properly”. But the PTAB credited the Patent Owner’s explanation that this cited testimony was in reference to only a minor issue with rubbing belt cleats, and the prototype was operating for its intended purpose. The PTAB also noted there was additional evidence, such as photographs on February 28, 2006, showing seed dust remnants, that confirmed the machine was working for its intended purpose.
The PTAB further rejected Petitioner’s argument that the prototype was not introduced in 2006 because the Patent Owner had represented that the invention “was introduced in 2007” during prosecution. However, the PTAB again agreed with the Patent Owner, finding that the 2007 introduction date referenced during prosecution was in reference to a “commercial embodiment,” and did not negate the 2006 prototype introduction date.
Thus, the PTAB found the Petitioner failed to show a “reasonable likelihood” of invalidating claims 16-22 because there was not a “reasonable likelihood” that the Morris and Hiniker webpages would qualify as prior art. With regard to challenged claim 23, the PTAB exercised discretion and determined that instituting an IPR on only one dependent claim out of eight challenged claims would not be an efficient use of resources, particularly where the evidence and arguments were directed primarily to disqualified references citing Chevron Oronite Co. v. Infineum USA L.P., IPR2018-00923, Paper 9 (Nov. 7, 2018).
Takeaway: Practitioners should be mindful that inventor testimony at the pre-institution phase of an IPR can be used to support a reduction-to-practice date, so long as the testimony is accompanied with corroborating evidence. Practitioners should also be mindful that the timing of such testimony does not allow for deposing the testifying inventor.
* Jessie was a summer associate in Jones Day’s Pittsburgh Office.
Matthew Johnson
Latest posts by Matthew Johnson (see all)
- Inventor Testimony of Reduction Date Leads to Denial - July 28, 2025
- “Settled-Expectations” Analysis May Leave Some Petitioners Feeling Unsettled - July 23, 2025
- Discretionary Denial Where Inventors Petitioned for Unpatentability - July 18, 2025