Sign up ×
Ask Patents is a question and answer site for people interested in improving and participating in the patent system. It's 100% free, no registration required.

I'm under the impression that being too specific is a bad idea in dependent claims. But is there a case when I really have to be, and therefore cannot use "further comprising" but rather I must use "wherein"?

share|improve this question

1 Answer 1

Dependent claims are the place to get narrower and are often chained to get more and more specific as they descend. The use of "further comprising" vs "wherein" is unrelated to the extent of narrowness you are adding. The parent claims requires an A and a B and a C.

"Further comprising an X "says you are adding a new element, X to the already required A, B, & C. "Wherein C is blue" gives more detail to an element already required.


Claims are often arranged in a hierarchy of increasing specificity and included structure. To infringe your patent an apparatus only has to fall under one of your claims.

If claim one says "A portion of a vehicle comprising an xyz transmission coupled to an abc drive shaft." Claim two might say. "The portion of a vehicle of claim 1 further comprising a two-wheel drive system." And claim three might say "The portion of a vehicle of claim 1 further comprising a 4-wheel drive."

In both claim 2 and 3 something is added to the elements of claim 1. This only works because claim 1 was patentable on its own. If some complete drive train is needed to get a patentable claim then claim 1 can say "a transmission coupled to a drive train". Claim 2 can be "the thing of claim 1 wherein the drive train is for 2-wheeled drive" and claim 3 can be "the thing of claim 1 wherein the drive train is for 2-wheeled drive."

share|improve this answer
But what about the case where Claim 1 is found to be too obvious? In order to infringe then a person has to either do Claim 1 and 2, or Claims 1, 2, and 3? – Friendly Nov 17 '13 at 4:28
If your broadest claim is properly rejected as not novel or as obvious during the patent prosecution process at the USPTO you will need to amend it to narrow it - not a big deal. If it is found not novel or obvious in court after it has been issued then you fall back to a dependent claims. That is one of the reasons to have dependent claims. – George White Nov 17 '13 at 4:48
In your case you could merge 1 and 2 into an independent claim 4, merge 1 and 3 into independent claim 5 and cancel claims 1,2 & 3. You end up with two independent claims rather than one. If that pushes you over three total independent claims you will need to pay an excess claim fee (<$200). – George White Nov 17 '13 at 4:56
If you really want optionality in a claim there are many ways to do it and many ways to mess it up. "comprising A, B and either C or D". "comprising A, B and at least one of C and D". "comprising a elongated member A having one end configured and adapted to directly operatively engage B, or optionally, to directly operatively engage C. – George White Nov 17 '13 at 4:57

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.