Yesterday's post focused on how Applicant admissions helped the Board to reach the conclusion of "obvious design trade off." Today I'll discuss the dissenting opinion in Parker, which found error in the Examiner's substitution rationale.
The Examiner offered this rationale for obviousness:
Horrigan et al. do not disclose the use of a flat wire coil, a round wire coil or a braided wire coil as a reinforcement means. Park et al. teach a catheter section or sheath with equivalent forms of stiffening members or reinforcement for kink resistance, i.e., a flat wire coil, a round wire coil and a braided wire coil.
It would have been obvious ... to have substituted the wire braid 35 of Horrigan et al. with a braided wire coil, a flat wire coil or a round wire coil as disclosed by Park et al. to have facilitated the manufacture of the catheter or sheath with a diameter suitable for application in an environment of increasingly small diameters.
(Internal citations omitted.)
Now, the strength of the substitution rationale depends on just how equivalent braids and coils really are. The dissent found that the Examiner's premise of equivalency was based on reading statements in the secondary reference (Park) in isolation.
Here's the statement which the Examiner relies on for equivalency:
[T]he structure of this ribbon coil-based catheter section [in FIG. 5] and the similar variation (224) shown in FIG. 6 using a wire or strand-based unwoven coils (226) are acceptable alternatives to the preferred variation shown in FIG. Nos. 3 and 4.
The dissent says that Park, when read as a whole, merely teaches the interchangeability of braids and coils in the specific context of Park's invention. The dissent says that Park is really about using a super-elastic material for the reinforcing mechanism, where the material changes shape when heat is applied. It's true that Park discloses the reinforcing mechanism can be a coil or a braid. But that doesn't mean that coils and braids are truly interchangeable -– only that the choice doesn't matter for Park's invention because Park's invention is about the material itself.
This same point was made (quite elegantly) by the Applicant in the Reply Brief:
[A teaching] that discusses the possibility of using a variety of reinforcements under conditions in which the particular type of reinforcement is of little significance to the teaching at hand, does not provide a skilled artisan with sufficient guidance to arrive at the invention claimed herein ...
A substitution rationale is strongest when it's simple substitution – when switching from braid to coil doesn't make a difference. Without such a teaching – or better yet, with a teaching that says it does make a difference – the rationale is weakened. Here, the Examiner specifically relied on Park to show that coils and braids were equivalent. I say the Applicant was on the right track in attacking this premise. The fact that the majority of judges didn't see it that way doesn't mean it's not a valid argument. I'd say the fact that the dissent was convinced shows the argument has some merit.