Using Dependent claims for avoiding infringement

[mlga]

In writing a claim, here is an area of confusion for me. For a simple example.....

I claim:

1. An apparatus comprising
(A) An X with an upper and lower surface
(B) A Y with an upper and lower surface
(C) A Z with and upper and lower end


2. The apparatus according to claim 1 wherein said Z may be of synthetic or natural materials such as plastics, metals or woods.

I know that my Z will be made of plastic, but should I say that it could be made out of any of these other materials so others can't simply change the material that it is made out of?  My independent claim is broad enough that I believe it covers any materials since the structure of it is novel for its use.  Or, Should I simply state that the apparatus is made out of plastic in claim 2?  Or not mention it alt all?

Is the use of dependent claims to avoid infringement, or to separate your invention from prior art that may already exist?

Any help would be greatly appreciated!

[mk1023]

I'm only an examiner and have no experience with the litigation side of the patent system so take what I say with a grain of salt.

By nature independent claims are broader than dependent claims. Because they are broader they should be easier to invalidate (less elements to find in prior art).

Hypothetically you could then be in a situation where a competitor could find some art anticipating an independent claim and then design around the dependent claims. In your scenario, if the competitor could find art anticipating your claim 1, they could just translate your plastic design to metal if you didn't have metal in claim 2. Thus dependent claims offer insurance in case your broader claims are read on by prior art.

From what I see a lot of attorneys put the kitchen sink in dependents. You may want to look at your invention in light of a draft of claims and think about how a competitor would try to design a similar product. Then revise your spec and claims to address any workarounds you see.

[mk1023]

2. The apparatus according to claim 1 wherein said Z may be of synthetic or natural materials such as plastics, metals or woods.

You would get a 112 2nd rejection for using "such as"

See: http://www.uspto.gov/web/offices/pac/mpep/documents/2100_2173_05_d.htm

[klaviernista]

Is the use of dependent claims to avoid infringement, or to separate your invention from prior art that may already exist?

Dependant claims are never used to "avoid infringement."  They are used (IMO) for three primary purposes, namely:

1.  As an insurance policy, should one or more of the independent claims be declared invalid or unenforceable;
2.  To more specifically claim features of the commercial embodiments of the invention;
3.  To include features that specifically read on a competitors product, if possible.

[mlga]

Thank you both for your replies!  This helps a ton.  And don't worry, I won't hold you to anything  .