Patent practitioners have a multitude of tools in their belt to deal with obviousness rejections. The trick is picking the right tool for the right set of facts. Teaching away is one tool that can be powerful for the right set of facts. It is one of the clear ways to attack even an amorphous obviousness rejection relying on common sense since it was explicitly blessed by the Supreme Court in KSR. Specifically, as discussed in a previous post, the Supreme Court explained that when the prior art teaches away from combining certain known elements, discovery of a successful means of combining them is more likely to be nonobvious.

But at the same time, our human brains are susceptible to cognitive bias, particularly the “Law of the Instrument”. As Wikipedia explains:

The law of the instrument, law of the hammer, Maslow's hammer (or gavel), or golden hammer is a cognitive bias that involves an over-reliance on a familiar tool. As Abraham Maslow said in 1966, "I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail.

When reviewing PTAB decisions, one gets the feeling that teaching away tends to be the patent practitioner’s golden hammer. However, the USPTO takes a strict view of teaching away - the prior art reference needs to do more than indicate a preference for something, or tout an advantage of a different feature than that claimed, for example. On the other hand, if the prior art explicitly states that a certain feature should not be used, that is likely a teaching away for adding the feature. Also, a prior art reference can be said to teach away when it suggests that the developments flowing from its disclosures are unlikely to produce the objective of the claimed invention (see In re Gurley, 27 F.3d 551, 553 (Fed. Cir. 1994)). The problem is that one rarely has such a set of facts in the eyes of the USPTO.

Thus, it is important to recognize the limitations of a teaching away argument. It is not sufficient where the prior art merely lists alternatives - that is not a teaching away from any of the alternatives because such disclosure does not criticize, discredit, or otherwise discourage them. See MPEP § 2143.03(VI), quoting In re Fulton, 391 F.3d 1195, 1201 (Fed. Cir. 2004). Likewise, indicating that a certain embodiment is not a preferred embodiment is not a teaching away.

Reading PTAB decisions lends one to believe that practitioners tend to over-argue teaching away - there are many PTAB decisions where the board dismisses teaching away arguments because the prior art does not actually teach away in the strict sense required by precedent. Rather than presenting a strong argument, mis-using teaching away only makes it easy for the examiner or PTAB to ignore your argument and affirm/maintain the rejection. Often times, there are facts to fashion another argument against obviousness, but that is lost because it is improperly forced into a teaching away position.

As an example, consider Audi’s application 16/077,002 related to a fuel cell stack. Claim 1 on appeal is listed below:

1. A bipolar plate for a fuel cell stack, comprising:
an anode half-plate on which an anode flow field is formed, and a cathode half-plate on which a cathode flow field is formed; and
a first elastic seal and a second elastic seal;
wherein the anode half-plate includes an anode sealing section of the anode half-plate that surrounds the anode flow field;
wherein the cathode half-plate includes a cathode sealing section of the cathode half-plate that surrounds the cathode flow field;
wherein the anode sealing section of the anode half-plate is in direct contact with the first elastic seal and the cathode sealing section of the cathode half-plate is in direct contact with the second elastic seal; andwherein the anode sealing section of the anode half-plate includes one or more sealing projections having a first height greater than the rest of the anode half-plate of the bipolar plate, and the cathode sealing section of the cathode half-plate is formed without a sealing projection and/or is substantially flat and has a second height greater than the rest of the cathode half-plate of the bipolar plate.

One of Audi’s arguments was the the prior art (Farrington) taught away from the anode sealing projection having a first height greater than the rest of the anode half-plate and the cathode sealing section having a second height greater than the rest of the cathode half-plate. This seems like a reasonable argument since the prior art taught that the anode and cathode plates each have peripheral projections and that it may be advantageous to limit the maximum height of the projections to that of the other features on the plates. In other words, limiting the height is directly opposite of the claimed feature (i.e., having the projection with a height that is NOT limited to the level of the rest of the half-plate). But alas, this is not a nail for the teaching away hammer… as the PTAB explains:

With regard to Farrington’s teaching that it may be advantageous to limit the maximum height of the projections to that of the other features on the plates, the Examiner correctly notes that a reference is not limited to its preferred embodiments, but must be considered for all that it teaches and reasonably suggests to one of ordinary skill in the art. Here, Farrington merely expresses a preference for a maximum height of projections 10, 11 to be the same as other features on the plates. In other words, Farrington recognizes that it may be advantageous to provide such a maximum height to these projections, but also recognizes the possibility that the maximum height of the projections may extend higher than the other features on the plates. Such a preference is not a teaching away. Appellant does not dispute or otherwise address the Examiner’s position that Farrington’s teaching of a preference for maximum projection heights being the same as other plate features suggests maximum projection heights greater than other plate features, albeit as non-preferred embodiments. Therefore, Appellant has not identified reversible error in the Examiner’s finding that it would have been obvious to provide Farrington’s projections with heights greater than other features on the half-plates.

This case illustrates that the teaching away argument can be elusive - even when you think you have it, you don’t. So, be careful not to over-rely on teaching away and reserve it only for those very particular situations when the facts cannot lead to any other conclusion. Here are some of the most common reasons the PTAB fails to find teaching away:

1. The prior merely expresses a general preference for an alternative invention but does not ‘criticize, discredit, or otherwise discourage’ investigation into the invention claimed;

2. The prior art has no actual criticism, but is merely silent - thus the argument that because the prior art does not disclose the claimed feature it teaches away from it is self-defeating;

3. Appellant fails to provide adequate analysis under the case law. Appellant fails to assert—let alone show—one skilled in the art “would be discouraged from following the path set out in the reference, or would be led in a direction divergent from the path that was taken by the applicant.”

4. The prior art’s mere disclosure of more than one alternative, even with respective advantages, does not constitute a teaching away from any of these alternatives.