US Federal Circuit Court Gives Guidance on Patent Claiming

In Retractable Technologies Inc v Becton, Dickinson and Company, the US Federal Circuit Court of Appeals struggled with the construction of claims in three patents owned by Retractable Technologies Inc, including claim 43 of US Patent No 7,351,224. The opinions provide some useful guidance for drafting claims for US patent applications. The patents relate to retractable syringes that employ a mechanism to retract the needle portion of the syringe into its body after the syringe is used to prevent accidental contact with the needle. The claimed syringe includes a "hollow syringe body comprising a barrel and having a front end portion and a back end portion". At issue was whether the body could comprise multiple parts or was limited to a one-piece structure. The patent included an independent claim reciting such a body, and a dependent claim limiting it to a "one-piece" barrel. Based on this, the doctrine of claim differentiation creates a presumption that the independent claim includes embodiments that have other than a one-piece body. However, the description described only embodiments with a one-piece body. In combination with statements in the background and summary, Judge Lourie, with whom Judge Plager concurred, found that the independent claim was limited to a one-piece body. They held that claim differentiation, in this case, did not lead to a strong implication that a multiple-part body was included, and so the presumption was overcome by the references in the specification to a one-piece body. The background section specifically stated that the prior art had not recognized a one-piece approach, and implied that the use of a one-piece body was central to the invention. However, Judge Lourie implied that the presumption may have been much stronger if a dependent claim had recited a multiple-piece body, and he noted that there is a very fine line between construing the claims in light of the specification and importing a limitation from the specification into the claims. Judge Plager, in a concurring opinion, admonished trial judges to turn a “deaf ear” to the “siren song of litigation counsel” urging them to construe the scope of claims to extend beyond what “is actually invented.” Chief Judge Rader, in dissent, thought the majority’s approach improperly imported limitations from the specification into the claims. Based on claim differentiation, which he found created a strong presumption, he thought it was clear that the independent claims were not limited to a one-piece body. Summary by: Tom Feather