Define Key Terms Tautologically

In the two-legged chair example discussed above, I used the word "connectors" to replace "nails, screws, bolts, and dowels". But what does that buy us? Does the term "connectors" include all possible types of connectors, including glue? It does if the patent attorney defines his terms tautologically rather than by simply listing the known choices.

A tautology is a classification scheme that covers all possibilities. One of the main tricks of drafting patents is to list the known choices on a piece of paper, and then classify them in some manner. The list of "nails, screws, bolts, and dowels", for example, can readily be classified into those that are threaded and those that are not threaded. This is immediately a tautology because everything must be either threaded or non-threaded. However, abstracting just another step, I can see that both threaded and non-threaded connectors are examples of a broader class of mechanical connectors.

Abstracting still further, I see that a sister class to mechanical connectors are chemical connectors. Once I contemplate chemical connectors, I can then very quickly think of all the various types of chemical connectors, glues, adhesives, and so forth.

But I am not done yet. If there are mechanical and chemical connectors, there is probably a third category, which I can call non-mechanical and non-chemical connectors. The rule is that if I can think of a genus of that class, I can claim the whole class. In this case I realize that one could conceivably hold a chair together using magnets. Claiming this class provides us with the final piece of out tautology. From a purely logical perspective, all connectors in the universe must be (a) mechanical, (b) chemical, or (c) non-mechanical, non-chemical, because that last category (non-mechanical non-chemical) is a catchall that includes everything that is not in one of the other two categories!

Figure 66 — Elements Subject To Variation Should Be Described Tautologically

Here's another tautology. In this case the inventor wants to claim a new type of balloon catheter. The preferred material is a biocompatible polymer known as polyester terephthalate, but the inventor wants to ensure that the claims cover all types of electrometric materials. He also wants to ensure that he will have plenty of leeway to narrow the scope during prosecution if necessary.

The way to do this is to describe the most preferred material as polyester terephthalate (polyester t- for short), and then list all the alternatives he can think of. In this case I know that polyethylene-t, dimethyl-t, and polytrimethylene t- would all be satisfactory. I then define all of those compounds as species in a class of homopolymers, and further define one of the species a subclass called "other". I am permitted to recite that subclass as long as I can identify at least one member in the subclass. In this case I hive off polytrimethylene t- so that I have at least one member in the other subclass.

Figure 67 — Tautological Claiming Of A Balloon Material

Of course, if there is a class called homopolymers, there must be a class called heteropolymers. I can define that class as long as I can think of at least one species. In this instance I realize that one could create block-copolymers, graft-copolymers and blends of the various homopolymers listed above. But once again I want to include a heteropolymer subclass called "other", so I identify the blends as a type of "other".

We then immediately appreciate that both homopolymers and heteropolymers fall within the family of polymers, and that leads us to appreciate that there must be a family of something that I could refer to as non-polymers. A little research on the Internet reveals that pre-polymers and quasi-polymers are considered to be non-polymers. Now that I have defined polymers and non-polymers, I can combine those families into a group called elastomers. Since the quintessential characteristic of a balloon is that it is elastic, I can confidently use the term "elastomeric material" in our claims, knowing full well that the term will cover every suitable type of material. Indeed, given the way I defined the term "elastomers", it is logically impossible for us to have missed anything. Anything I don't know about would be covered by one or more of the classes or subclasses.

A bonus of this approach is that I provide myself with plenty of wiggle room in case I need to narrow the scope of the claims with respect to the balloon material. For example, if the examiner rejects the claims based upon a reference that teaches homopolymer materials, I could probably still claim heteropolymer materials. If the examiner cites references against us that teach co-polymers, I would probably still have a good case for listing elastomers other than co‑polymers. This is all in stark contrast to an application that merely recited polyester, polyethylene, dimethyl, and polytrimethylene terephthalates. In that case the citations might be terminal to patentability.

Of course, in order to properly support broad claims through the use of tautologies, one has to draft the claims before the specification. One could work the other way around, by drafting the specification and examples before the clams, but that leads to either short applications that cannot support broad claims ,1 or long applications with dozens and dozens of examples. Claims will not be invalidated on section 112 grounds simply because the embodiments of the specification do not contain examples explicitly covering the full scope of the claim language.