In its August 14, 2013 opinion in Hamilton Beach Brands, Inc. v. Sunbeam Prods., Inc., the US Court of Appeals for the Federal Circuit affirmed the US District Court for the Eastern District of Virginia's ruling that Hamilton Beach's asserted patent claims for its slow-cooker were invalid under the pre-AIA on-sale bar. The district court also found that Sunbeam did not literally infringe the asserted claims of US Patent No. 7,947,928 (the '928 patent).

Both parties compete in the small kitchen appliance industry and sell versions of slow-cookers. Hamilton Beach alleged that Sunbeam's slow-cooker infringed claims of the '928 patent. Sunbeam moved for summary judgment, arguing that:

The district court granted Sunbeam's motion for summary judgment, ruling that Hamilton Beach's purchase order with its foreign supplier was an invalidating commercial offer for sale under the Section 102(b)'s on-sale bar, which invalidates a patent when the invention was sold or offered-for-sale more than one year before the effective filing date (the critical date) (35 U.S.C. § 102(b)). Hamilton Beach appealed to the Federal Circuit.

On appeal, the Federal Circuit, in a split decision, affirmed the district court because both conditions of the on-sale bar were met before the critical date. Under Pfaff v. Wells Elecs., Inc., the two conditions triggering the on-sale bar are that:

The Federal Circuit explained that a commercial offer for sale for purposes of Section 102(b) occurs when the other party could make a binding contract by simple acceptance. It also noted that there was no "supplier exception" to the on-sale bar and that an offer for sale by a foreign supplier directed to the US may qualify as an invalidating activity. Hamilton Beach's foreign supplier responded that it was ready to fulfill the order before the critical date, which the court interpreted as the supplier making an offer to sell the slow-cookers to Hamilton Beach. This constituted a commercial offer for sale, allowing Hamilton Beach to accept the offer whenever it pleased, and fulfilling the first Pfaff prong.

The invention met the second prong, ready for patenting, because the descriptions and depictions of the slow-cooker were sufficiently precise to enable a person of ordinary skill to build the invention. Specifically, there was evidence in the form of:

This case is noteworthy for invalidating patents under the on-sale bar based on Hamilton Beach's outsourcing of its manufacturing to a foreign supplier. Circuit Judge Reyna, in his dissent, faulted the majority's:

Judge Reyna cautioned that the majority's approach may be problematic for smaller companies and other inventors who lack internal manufacturing capabilities. He noted that under this case, the on-sale bar may be triggered even by a single offer to buy and the experimental-use exception may not be able to save.