Troutman Sanders LLP: Judge Spencer Finds Slow Cooker Patent Invalid Based on "New Matter" and On-Sale Bar Defenses

Troutman Sanders LLP: Judge Spencer Finds Slow Cooker Patent Invalid Based on "New Matter" and On-Sale Bar Defenses

By Dabney Carr

In a July 13 decision found here, Judge Spencer held on summary judgment that Hamilton Beach's patent on a clip to prevent the lid of a slow cooker from sliding off during transportation was invalid based on Sunbeam's "new matter" defense and held in the alternative that Hamilton Beach's commercial embodiment of the patented invention invalidated the patent under the on-sale bar of 35 U.S.C. § 102(b).  Hamilton Beach Brands, Inc. v. Sunbeam Products, Inc., Case no. 3:11CV345, 2012 U.S. Dist. LEXIS 97923 (E.D.Va. July 13, 2012).

Judge Spencer also granted Sunbeam summary judgment that its Crock Pot® Cook & Carry Slow Cooker did not literally infringe the Hamilton Beach patent but denied summary judgment on infringement under the doctrine of equivalents. 

As we posted hereJudge Spencer denied Hamilton Beach's motion for a preliminary injunction last August. Trial was set for March of this year, but the trial date was continued pending Judge Spencer's decision on the parties' cross-motions for summary judgment. Given the parties' long history of litigation, it is likely that Judge Spencer's ruling will be appealed, and so this crock pot saga is far from over.


While Judge Spencer agreed with Sunbeam on both of its literal infringement arguments, he denied summary judgment on infringement under the doctrine of equivalents, holding that further factual development was necessary. As a result, Sunbeam's victory turns on the Court's findings of invalidity.

Invalidity - "New Matter"

Perhaps the most interesting aspect of the decision is the discussion of Sunbeam's "new matter" defense. Hamilton Beach claimed priority for the patent in suit (the '928 patent) through a chain of continuation applications to the filing date of an earlier patent, the '831 patent

Sunbeam asserted that new matter inserted into the '928 specification barred reliance on the '831 patent's priority date. Sunbeam pointed out that the latching mechanism on the Sunbeam product was the reverse of the mechanism disclosed in the '831 patent. Sunbeam's product had a clip mounted on the lid, while the '831 patent described a clip mounted on the side of the slow cooker. Sunbeam claimed that Hamilton Beach broadened both the meaning and the location of the "clip" in the '928 patent application in an attempt to cover both mounting locations. 

Hamilton Beach argued that the original disclosure of the '831 patent supported mounting of the hook and clip on both the lid and the side of the product. Judge Spencer rejected this argument, holding that the '831 patent did not disclose clips that included a "catch" as in the '928 patent and that the description of the location of the clip in the alternative in the '928 patent was "conspicuously absent" from the '831 patent disclosure. The notion that the '831 patent contemplated "clips" having a "catch" or that the "catch" might be mounted on the side wall, the Court held, "strains credulity." 

A finding of invalidity necessarily followed from the holding that the '928 patent could not claim the earlier filing date. Without the benefit of the filing date of the '831 patent, both Hamilton Beach's own slow cooker and the accused product anticipated the asserted claims under 35 U.S.C. § 102(a) and (b). 

Invalidity - Alternative Ruling

Despite his ruling on Sunbeam's new matter defense, Judge Spencer went on to address Sunbeam's alternative claims that, even if the patent was entitled to the '831 patent's priority date, Hamilton Beach's slow cooker invalidated the '928 patent under the on-sale and public use bars of 35 U.S.C. § 102(b) and that the '928 patent was obvious over the prior art. 

  • The On-Sale Bar

The key issue for the on-sale bar was whether the claimed invention was the subject of a commercial offer for sale as defined by Group One, Ltd. v. Hallmark Cards, Inc., 254 F.3d 1041 (Fed. Cir. 2001) [enhanced version available to subscribers], before the critical date. Prior to the critical date, Hamilton Beach met with buying agents for several retailers and made presentations that included price quotations and computer renderings of its slow cooker that appeared to depict all of the limitations claimed in the '928 patent. 

Judge Spencer agreed with Hamilton Beach, though, that its product presentations did not constitute binding contractual "offers" for sale. The Court looked to practices in the small kitchen appliance industry and found that a true commercial "offer" required a purchase order from a customer which is accepted by the seller's agreement to ship the product. The standard purchase orders and vendor agreement submitted by Hamilton Beach established that prior communications and interactions between the parties, such as product presentations, did not form a sales contract and so could not qualify as an offer for sale.

That left Hamilton Beach's contract with its supplier to manufacture the Hamilton Beach slow cooker as the only possible offer for sale before the critical date. Shortly before the critical date, Hamilton Beach had sent a purchase order to its supplier for production of the patented slow cooker. That purchase order, however, was an "offer to buy" not an "offer to sell." Where there is an offer to buy in the form of a purchase order, the key issue is whether the offeree accepts the offer before the critical date. 

Four days before the critical date, Hamilton Beach and its supplier engaged in a series of emails in which the supplier confirmed receipt of the purchase order, acknowledged the quantity ordered, described arranging for QC inspection and promised a ship date. The supplier's email, Judge Spencer held, was sufficient evidence of acceptance because it objectively manifested the offeree's assent to the purchase order.

Hamilton Beach argued that since the sale was "F.O.B." outside the U.S., the sale was not consummated in the U.S. as required by § 102(b). Judge Spencer rejected this argument, noting that offers for sale by foreign parties that are directed to U.S. customers at their place of business in the U.S. qualify as invalidating sales. That being the case, "the Court can discern no reason why a accepted offer to buy by a U.S. customer directed to a foreign entity should not also qualify." 

Once Judge Spencer determined that the Hamilton Beach product had been the subject of a commercial offer for sale before the critical date, he Spencer quickly concluded that Hamilton Beach's detailed drawings and descriptions of the product established that the product was "ready for patenting" at that time. What is important, the Court held, is whether one of ordinary skill in the art could practice the invention given the drawings, descriptions and similar tools. Further refinement of the product at a later time did not undermine that conclusion.

  • Public Use

Judge Spencer did not agree, however, that Hamilton Beach's public demonstrations of the product to retail customers constituted invalidating public use. At these demonstrations, the Court found, the product was only described or visually displayed, not used.

  • Obviousness

Finally, Judge Spencer quickly rejected Sunbeam's claim that it was obvious to devise a slow cooker with a sealable lid. In support, Sunbeam listed multiple prior art combinations, but did not set forth how the references fit together to render the claims obvious nor did it submit any evidence showing why it would been obvious to combine elements from those prior art references.

Copyright © 2012, Troutman Sanders LLP

Virginia IP Law
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Virginia intellectual property lawyers & attorneys of Troutman Sanders Law Firm, offering services related to patent litigation, trademarks, copyrights, trade secrets, service marks and unfair competition, serving Virginia, Maryland, Washington D.C. and the Eastern United States.


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