Means Plus Function Claim Language. Episode 94

What Is Means Plus Function Claiming?

In this episode, I’m going to talk about a special way to claim your invention. I probably should have discussed it way back when I talked about claim drafting, but I don’t think I did—or if I did, I probably glossed over it.

If you haven’t listened to all my episodes on claim drafting and how to figure out what your invention is, I’d recommend listening to those first. They’ll help you see the forest for the trees, because this episode is pretty technical.

So, what is means plus function claiming?

An Example: Connecting a Board to a Pipe

Let me give you an example. Let’s say that, as part of your invention, you claimed that two things were attached together using a certain connecting object. Say a board is connected to a pipe in your invention with a nail. So in your claims, you write: “a device having a board, a pipe, and a nail that connects the board to the pipe.”

This is a logical claim, but if you listened to my episodes about claims being too narrow or too broad, then hopefully this jumps out at you as something someone could easily design around.

What if someone used a screw to connect the two things? Or a bolt, or a staple, or glue, or even welded them? If they did those things, they wouldn’t be infringing your patent, because you claimed a nail connecting the board and the pipe.

Now, it’s possible you could still get them for infringement using the doctrine of equivalents—which I talked about in Episode 76—but glue isn’t really equivalent to a nail, even though they both secure things together. It would probably be an uphill battle to argue that glue and a nail are equivalent.

And in the end, you don’t really want to have to rely on the doctrine of equivalents. You want a clean and simple case of direct infringement.

The Kitchen Sink Approach vs. Means Plus Function

One way to try to avoid that issue is to list every type of connecting member you can think of and put them all in the claims. So you might say: “a device having a board, a pipe, and at least one of a nail, screw, bolt, glue, and staple that connects the board to the pipe.”

That’s one option, but maybe you’re missing some things, and the claim might just get really long if you’re trying to throw in the kitchen sink.

Another way to do it is by claiming the function, and this is where means plus function comes in.

Instead of claiming a physical object like a nail, you say: “a board, a pipe, and means for connecting the board and pipe together.” When you word it like that, you really cover everything.

Why Means Plus Function Isn’t So Simple Anymore

Sounds simple, right? Just claim your invention in a functional way and not as a specific physical object. Technically, you are allowed to do this. It’s in 35 U.S.C. §112(f).

People used to draft claims like this all the time, but then the courts started to push back. They ruled that if you use this kind of language in your claim, somewhere in your specification—that’s the written description part—you have to describe what the actual structures are that can perform the function.

So if you wrote “a means for connecting a board to a pipe” but nowhere in your description did you mention examples like a screw or a nail, then you’re going to get an objection for indefiniteness.

If you still want to use means plus function language, you can—but you’ll need to include something in your description like: “A variety of members can be used for the means of connecting a board to a pipe, such as a nail, screw, bolt, glue, and staple.”

If you do that, then your claim shouldn’t get objected to for indefiniteness. Your claim will also cover all the structures and their equivalents that you disclosed in your specification. The court is supposed to use the broadest reasonable interpretation of what those means are.

If you use the phrase “means for,” or if it’s a method claim and you use “steps for,” and there is functional language, make sure you have corresponding structures or steps described in your specification.

Avoiding the Trigger: “Means” vs. “Member”

There’s another way around the problem of means plus function.

What if, instead of saying “a means for connecting the board to the pipe,” you said, “a connecting member to connect the board to the pipe”? Sounds like the same thing, right? A connecting member to do something is basically the same as saying a means for doing something.

The good news is that if you use the term “connecting member” or “connecting element,” it doesn’t automatically trigger the requirement that you disclose all the possible connecting members in your specification. The phrase “means for” is like a magic trigger. If you avoid that wording and use something like “connecting member,” you’re actually safer.

Even so, I’d still list a bunch of types of connecting members in the description just to be safe. But technically, it doesn’t trigger §112(f), which is specific to means plus function language.

Now, be cautious. Some terms can still trigger §112(f) even if they don’t use “means.” Words like “mechanism for,” “element for,” “machine for,” or “device for” can fall into a gray zone. So regardless of how you claim your invention, always include example structures in your application.

Trends in Claim Language: “Configured To” and Other Terms

This isn’t just my opinion. Historically, in the 1970s, over half of all patents had means plus function language. Now, it’s down to around 5%. It’s something patent attorneys generally avoid.

Instead of using “means,” people often use terms like “configured to.” So I might say, “a connecting member configured to connect a board to a pipe.” That gives you a similar level of functional breadth without automatically triggering §112(f).

Other phrases people use include “adapted to,” “capable of,” or “designed to.” Each of these has pros and cons, and their effectiveness depends on how the courts interpret them.

How the Courts Decide What’s Triggered

What’s important is whether a person having ordinary skill in the art would read that language and interpret it as indicating a specific structure or not.

There are lots of court cases dealing with whether a claim is a means plus function claim or not. I’m not going to go into all of them here, but be aware that there are exceptions. Sometimes even when the word “means” is used, it doesn’t trigger §112(f), and sometimes it gets triggered even without the word “means.” So nothing is 100% guaranteed either way—use that language at your own risk.

If you’re dealing with software or computer-related patents, there’s even more nuance involved in determining whether a claim falls under §112(f), but that’s not something I’m covering in this episode.

Strategies for Using Means Plus Function (or Not)

Some people like to include some claims with means plus function language and others with actual physical structures to cover all their bases. That’s a solid approach.

Personally, I almost always avoid means plus function language, and I would never rely only on it. I don’t see a good reason to invite the examiner to issue an objection, so I’ll use other language.

However, I still treat the written description as if I had used means plus function language by including lots of physical structures as possible variations. That way, if the examiner does decide I’ve triggered §112(f), my specification still provides the necessary support.

I’m Adam Diament, and until next time, keep on inventing.