The claims are one of the most important sections of a patent. They describe in detail exactly what has been invented and therefore, what is protected by the patent. If a patent is allowed and later on an infringement case is initiated, the courts will scrutinize the claims in order to establish whether or not the rights of the patent owners were actually infringed upon. Claims are the definition of that for which prosecution is granted.

Since the claims are so important, there are many rules involved with them. This section only briefly summarizes a few of the major points involved with writing the claims.

There may always be more than one claim in an application if the invention warrants it. These claims may even refer back to and further limit another claim in the same application (these are called dependent claims).

A dependent claim may even refer to more than one other claim. Dependent claims that refer back to more than one claim are considered multiple dependent claims.

Multiple dependent claims may only refer to the claims they are based on in an alternative form.

Alternative expressions include the terms “or” and “optionally”. Multiple dependent claims must refer back to preceding claims in the alternative. They may never refer back in the cumulative “and”.

acceptable phrases using “or” terminology

• “wherein R is A, B, C or D”
• “made entirely or in part of”
• “iron, steel or any other magnetic material”

“optionally”

• an alternative format which requires some analysis before concluding whether or not the language is indefinite
• the language “containing A, B and optionally C” is considered acceptable alternative language because there is no ambiguity

Examples
Here is an example of a good multiple dependent claim; "a gadget according to claims 2 or 3, further comprising." Notice that the statement includes "2 or 3". It would never be acceptable to state "2 and 3". This is a key point to remember. In addition, multiple dependent claims cannot depend on other multiple dependent claims.

It is also important to recognize that the claims should be presented in a particular order. Claims should be arranged so that the first claim is the broadest one and subsequent claims should narrow in scope the further down they are in the list. Claims that are similar should be grouped together and product and process claims need to be grouped separately.

When there is more than one claim, each one should be separated by a line of indentation. Each claim should begin with a capital letter and end with a period. Furthermore, they should begin with "I (or we) claim" or "The invention claimed is". In addition, each paragraph within the claims should be separated by a semicolon or a comma.  

Of course, there is much more involved in the claim writing process. This fundamentals course only includes a sampling of the detailed rules and laws of claims.