3 legged chair vs 4 legged chair

[jk2000]

Hi folks,

So, if I say "chair comprising 4 legs" then that takes into account anything that includes more than 4 legs.

But if I had a claim for "chair with 3 legs," what would you say if the examiner pointed to the above disclosure and said it would be obvious to have 3 legs because 4-legged chairs already exist.

To make it simple (I think), let's say that there is no reason given for the 4 legs and no reason given for the 3 legs.  How would you go about arguing that it's not obvious?

[Robert K S]

I'm not aware of any precedent holding that "with" is not open-ended language like "comprising".  As such, a 4-legged chair would not just render obvious a "chair with 3 legs", it would anticipate a "chair with 3 legs", because a 4-legged chair is a chair with three legs.

If you want to show that a chair with only three legs is not obvious in view of a chair with four legs, you may be required to show an unexpected result extending from the reduction in number of legs.

"[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation."  In re Aller, 220 F.2d 454, 456 (C.C.P.A. 1955). However, before a variable can be optimized through routine experimentation, it must first be recognized in the prior art as result-effective. See In re Antonie, 559 F.2d 618, 620 (C.C.P.A. 1977).

Number of legs is probably fairly well known as a result-effective variable for achieving stability.  If you somehow discovered that reducing the number of legs actually increased stability (and provided the prior art showed no 3-legged chairs), you might have a non-obvious invention.

[jk2000]

Thanks Robert.