Patent It Yourself - PDF Archive

ChaPter 9 | Now for the LEGALESE—The CLAIMS | 249
Common Misconception: The limitations in a dependent
claim will narrow its independent claim.
Fact: The independent claim is interpreted independently of
its dependent claims and the latter never narrow the former
although they can make the independent claim broader by
claim differentiation.
Claims of Different Scope
The concept of claims of different scope (independent
and dependent) is confusing to most inventors. Here’s
another way of explaining it, if you still don’t understand.
An independent claim (IC) is one that doesn’t refer
back to any previous claim. For example, “1. A telephone
comprising (a) a base, (b) a handset, and (c) a rotary dial,”
is an example of an IC.
To write another independent claim like Claim 1 (C1),
but which is narrower than C1 by reciting a base of black
plastic, simply repeat all of Claim 1 and add that the base
is black plastic. For example, “2. A telephone comprising
(a) a base of black plastic, (b) a handset, and (c) a rotary
dial,” is an example of a second IC which is narrower
than C1.
However, there’s an easier, shorter, and cheaper way
to avoid repeating all of C1 each time: Simply write a
claim that refers to the IC 1 so as to incorporate all of
it by reference, and then state one or more additional
elements, and/or recite one or more elements of the
incorporated claim more specifically. Such a shorthand
claim is called a dependent claim (DC). A DC is thus one
that refers back to and in corporates all of a preceding
claim and adds or modifies one or more limitations to
recite the invention more narrowly. For example, “2´. The
telephone of Claim 1 wherein said base is made of black
plastic,” is a dependent claim which has the same scope
as C2. C2´ will be interpreted as if it included all of the
subject matter of C1, together with the additional subject
matter in C2´.
It follows that to infringe a DC, a device must have all
of the elements of the DC, plus all of the elements of the
incorporated claim.
Thus, adding a DC to recite a specific feature of your
invention won’t broaden or narrow your coverage; it will
just provide another, yet more precise, missile. The eight
reasons for including DCs are in Section J.
Also note that a DC can refer back to a preceding
claim, and the preceding claim can in turn refer back to
a further preceding claim. To infringe such a third-level
DC, the device must have all of the elements of all three
claims in the chain.
If you still don’t get the principle of broad and narrow
claims, here are three simple claims that everyone can
understand:
1. A house that has a sloping roof with a gable.
2. The house of Claim 1 wherein said gable has a
dormer.
3. The house of Claim 2 wherein said dormer has eight
panes of glass.
Claim 1 is very broad: It will cover any house that has a
sloping roof with a gable. Thus it may cover, say 30 million
houses in the United States. Claim 2 is of intermediate
scope; since it incorporates all of Claim 1 and has additional
verbiage, making it longer than Claim 1. However Claim
2 is narrower in scope since it is limited to houses with
sloping roofs that have a gable with a dormer. Thus it will
cover fewer houses, say ten million in the U.S. Claim 3
is still longer than Claim 2, but is far narrower since it is
limited to houses with sloping roofs that have a gable with
a dormer with eight panes of glass. Thus it will cover fewer
houses still, say one million houses in the United States.
Note that I made the number of the independent claim
(#1) bold and I indented the dependent claims to indicate
the dependency so that each dependent claim is nested
under its referent claim. This is optional but desirable since
it makes the claims clearer. As indicated above in Section
G1, if you’re working on a computer, use its “windows”
function (if available) to keep your independent claim
displayed while you write your dependent claims.
K. Drafting Additional Sets of Claims
After you’ve written your first independent claim (IC) and
all the dependent claims you can think of (all numbered
sequentially), consider writing another set of claims (an
IC and a set of dependent claims) if you can think of a
substantially different way to claim your invention. See the
prior-art patents and the sample set of claims at the end of
this chapter (Fig. 9A) for examples of different independent
claims on the same invention. Your second set of dependent
claims can be similar to your first set; a word processor
with a block copy function will be of great aid here. Writing
more sets of claims will not always give your invention
broader coverage, but will provide alternative weapons to
use against an infringer. That is, writing a second set of
claims is like going into battle with a sword as well as a gun.
Also, writing more sets of claims will give your examiner
additional perspectives on your invention. That is, your
chances of getting your examiner to bite will be increased if
you present many flavors to choose from.