Rader: Reviving the Doctrine of Equivalents

By Dennis Crouch

John Deere v. Bush Hog (Fed. Cir. 2012)

When I was a kid, we had a “John Deere Bush Hog” for mowing pasture land (AKA “bush hogging”). Several years later I learned that we really had a John Deere brand rotary cutter. The Bush Hog company also sells its own brand of rotary cutter. In this case, Deere sued Bush Hog for infringing its U.S. Patent No. 6,052,980. That patent claims a deck for a rotary cutter that is more easily cleanable.

One claim limitation required that an upper deck wall be sloped “rearwardly from said central portion into engagement with, and being secured to, said lower deck wall.” Apparently in the accused Bush Hog device, the upper deck wall does not directly contact the lower deck wall. As per usual, that infringement issue was posed as a claim construction question determined by the judge as a matter of law. Here, the district court judge ruled that the “into engagement with” limitation required direct contact and that there could therefore be no literal infringement of the claim. When pressed on the doctrine of equivalents, the district court revived the vitiation exception to the DOE and ruled that the claims could not be extend to cover no direct contact when they claim the exact opposite of direct contact.

On appeal, the Federal Circuit doubly rejected the district court opinion.

On claim construction, the court ruled that “engagement” between two metal sheets does not require direct contact, but may instead be facilitated through indirect contact. The court demonstrated this conclusion with reference to a drawing from the Deere patent where a filler plate (shown in blue) provides the engagement between the upper deck (yellow) and the lower deck (red).

On Vitiation of the Doctrine of Equivalents: Although dicta, Judge Rader continued his opinion a repudiation of the district court’s mistreatment of the vitiation doctrine. Of course, the doctrine is regularly mistreated because it is lacking in logical sense. The doctrine of equivalents allows a patentee to capture some amount of scope that goes beyond the literal scope of the claims as written. As a matter of course, this always involves rejecting the literal bounds created by one or more claim limitation. However, the doctrine of vitiation rises to stop a patentee from applying the DOE in a way that negates the meaning of one or more claim term. In his opinion, Chief Judge Rader attempts to cut through this knot and cautions against the programmatic use of the vitiation doctrine:

Courts should be cautious not to shortcut this inquiry by identifying a “binary” choice in which an element is either present or “not present.” Stated otherwise, the vitiation test cannot be satisfied by simply noting that an element is missing from the claimed structure or process because the doctrine of equivalents, by definition, recognizes that an element is missing that must be supplied by the equivalent substitute. If mere observation of a missing element could satisfy the vitiation requirement, this “exception” would swallow the rule. . . . [P]reserving the doctrine in its proper narrowed context requires a court to examine the fundamental question of whether there is a genuine factual issue that the accused device, while literally omitting a claim element, nonetheless incorporates an equivalent structure.

Chief Judge Rader goes on to explain how the suggested use of the DOE in this case likely does not vitiate the relevant claim terms.

In this case, the district court construed “contact” to require “direct contact,” and thus found that allowing “no direct contact” would vitiate the court’s construction. Yet, a reasonable jury could find that a small spacer connecting the upper and lower deck walls represents an insubstantial difference from direct contact. See TurboCare Div. of Demag Delaval Turbomachinery Corp. v. Gen. Elec. Co., 264 F.3d 1111, 1124 (Fed. Cir. 2001) (construing claim term “contact” to require “touching” but remanding question of whether “indirect contact” could be equivalent). Thus, the trial court erred by invoking the vitiation

Rader’s basic idea here an attempt to move away from the technical limitations that have pushed the DOE toward obscurity over the past several years. In his view, vitiation should not be seen as a technical doctrine but instead simply a tool for district courts to use when the claim language is so far from the asserted equivalent that no reasonable jury would find infringement.

On remand, the new claim construction breathes new life into Deere’s infringement case.

Dennis Crouch

About Dennis Crouch

Law Professor at the University of Missouri School of Law. Co-director of the Center for Intellectual Property and Entrepreneurship.

12 thoughts on “Rader: Reviving the Doctrine of Equivalents

  1. There is nothing “unfair” about giving the rest of the answer that is required with your ‘simple’ answer.

    Why do you think that unfair? Quite the contrary, it is the epitome of fair.

    As to your further questions, you are aware that DOE is not applied to claim scope at all, but rather – and explicitly – to elements of a claim, right? This is to expressly not widen literal claim scope.

  2. Anon, you are not fair. You asked me how the owner of a claim can possibly get, in a country that eschews a DoE, coverage as wide as that which he can expect to get under the DoE in the USA.

    I answered.

    At which point you announce that I “want” to fundamentally change US claim construction. Who knows what I “want”. That is not of interest to readers. All I’m doing here is lamenting the uncertainty that comes bundled with a DoE, and asserting that it is unnecessary complexity. Let’s ebate that, shall we?

    In any case, isn’t the English way to construe claims compatible with Phillips? Is it mandatory on judges in the USA, always to widen “literal” claim scope using a DoE? What if Rader CJ were from now on to adopt English-style claim construction rhetoric and analysis, before going on to consider any DoE? In what way would he then not be following SCOTUS precedent?

    Revolutionary? I don’t see it that way.

  3. Thanks MaxDrei,

    So in reality, you not only want to change to eliminat DOE, you also want to fundamentally change US claim construction I order to support that ‘simple’ DOE elimination change…

    Why didn’t you just say so?

  4. You know, anon, I think I do not miss the point.

    Tell you? Purposive construction, namely, the UK Supreme Court (Leonard Hoffmann) way to construe claims under the EPC. Simply ask: for the PHOSITA reader, what was the inventor using the language of the claim to mean. That, my friend, is the irreducible minimum of complication. It couldn’t be simpler, and it gets you to the right result every time. It’s an alien way of thinking, to any US patent attorney, I know, but if you lack the time to read up the English caes, ask your in-house global pharma colleagues for a tutorial, whenever you get the chance. They can surely tell you.

  5. I think you quite miss the point of the quote in the “no simpler” emphasis.

    Tell me (if you can), how is a patent holder in a system that employs the Doctrine of Equivalents going to obtain the same strength of patent coverage in a system that does not emply the Docteine of Equivalents?

  6. For once we can agree on something, anon. As simple as it can be made, but no simpler. Indeed.

    For the last 30 years I have observed (and contributed to) how two jurisdictions (England and Germany) compete with each other for the better way to construe claims, under the identical Statute (the European Patent Convention). One (Germany), swears by the Doctrine of Equivalents, tracking the USA. The other, England, regards the Doctrine of Equivalents as unnecessary and unhelpful. Innumerable cases litigated in both Germany and England, and unending competition, between the litigators of England and those of Germany for the lucrative litigation cases, tends to expose to harsh criticism whether or not the Doctrine of Equivalents is a “good thing”. Actually, it’s rubbish. Simpler is indeed better. Under the local Patent Statute, wherever in the world you are, you either infringe a claim or you don’t. In the Statute, there’s no such thing as “Infringement by Equivalent”. Basta.

    Germany used to have one level of obviousness for its 20 year term utility patents and a different level for its 10 year utility patents. But that was too complicated. So now it has just one level Y/N. In the UK, pre-EPC, there was a plethora of grounds of invalidity. Now, under the EPC, there are just three. Simpler and better. Experience since 1978 shows that, in fact, you only need three. And experience shows that a DoE is a hindrance, not a help, unless you are a litigator and desire uncertainty.

    If you disagree, tell me what unique feature of US patent law makes a Doctrine of Equivalents unavoidable. Take “engaged” here. The DoE just made everything more confused, didn’t it?

  7. How much simpler it would all be to get rid of the Doctrine of Equivalents altogether.


    “Everything should be made as simple as possible, but not simpler.” – A. Einstein. (emphasis added)

  8. What a shame we have to debate whether the notion of vitiation is itself vitiated. How much simpler it would all be to get rid of the Doctrine of Equivalents altogether.

    Look, here, it is all about the word “engaged”. Consider upper and lower deck plates secured to each other as in the patent, spaced apart by the weld bead with which they are welded together. Are the deck plates in contact with each other? No. What difference is there, if (as in the accused embodiment) the weld bead is supplemented by a fillet plate? The plates are still secured to each other. They are still not in contact. This I think is what Rader CJ is thinking.

    I regret Rader’s invocation of toothed gears to exemplify “engagement”. Of course such gears are engaged. But so what? Better would be a container ship secured to a quay. Is it “engaged” with the quay. I think not. But, looking at the patent in issue, if its plates are “engaged” with each other when they are welded together, then so too are the plates of the accused embodiment, when welded together. The Doctrine of Equivalents is positively detrimental to clarity of thinking, and unnecessarily complicates what ought to be simple cases. For that reason alone, it should be knocked on the head, and got rid of.

  9. How many ears has Davy Crockett? Three. A left ear, a right ear and a wild front ear.

    Readers in Europe would like more comment on this case. Anybody able to oblige, while I download the Decision and read it myself?

  10. In any event, the DOE is almost always just shorthand for “somebody failed to construe the claim properly.”

    That’s a novel way of looking at the doctrine.

  11. King of the Wild Patent Frontier: I don’t see how the vitiation doctrine lacks logical sense, once you understand Festo’s rule that DOE is applied on a limitation-by-limitation basis, and not to the claim as a whole. Am I missing something?

    I don’t think so. I liked your explanation.

    In any event, the DOE is almost always just shorthand for “somebody failed to construe the claim properly.”

    If the term “engagement” was properly construed to mean “direct contract”, then there should be no infringement under the DOE.

    If the term “engagement” should have been construed to require “direct or indirect contact”, then there is literal infringement, and there is no need to get into the DOE/vitiation mindtrap. I’m not sure why Rader bothered. Maybe he’s fantasizing about another Supreme spanking in the distant future.

    the new claim construction breathes new life into Deere’s infringement case.

    And possibly into Bush Hog’s invalidity case.

  12. Rader’s statement of the vitiation doctrine seems pretty straight forward: to claim equivalence, the accused device must have some structure that might be deemed equivalent. For example, if a claim requires that two things be connected with a screw, any fastener might be equivalent, but if nothing connects the two things, there is no structure which could be deemed equivalent. To allow the absence of a screw to be deemed equivalent to the recited screw would entirely vitiate the screw limitation. This is old stuff and I don’t see any conceptual problems or knots. I don’t see how the vitiation doctrine lacks logical sense, once you understand Festo’s rule that DOE is applied on a limitation-by-limitation basis, and not to the claim as a whole. Am I missing something?

Comments are closed.