When exactly patents fall under double-patenting?

Question

I have an omnibus specification and I want to split it into multiple patents at a later point. I'm little afraid that accidentally I'll double patent my work.

So I just need some clarification.

I have Patent A, B, C.

Patent A is the main patent. It contains step X and Y.

Patent B is a derivative patent that relies on Patent A functionality. The steps will look like W, X, Y, Z

Patent C also a derivative patent that relies on Patent A functionality. The steps will look like U, X, Y, Z

Since B and C claims contains Patent A claims, does this considered as double-patenting?

Answer 1

In your example, you say "patents B and C contain patent A's claims". That is not the case in your example. They build upon the information taught in patent A.

The issue will be whether the claims in B and C are obvious variants from the teachings embodied in the claims of patent A. We can't tell that from "W, X, Y, Z". If adding step W at the start and adding Z to the end of the steps is not an obvious variant of X, Y there is no double patenting.

If an examiner asserts that there is a non-statutory double patenting issue, you can argue, amend, or sign a terminal disclaimer. In a terminal disclaimer you get the multiple patents but agree that when one expires they all expire and that they will always be commonly owned.