To obtain a patent, an inventor must file an application with the US Patent & Trademark Office (“USPTO”). The most important part of the application — and often the most difficult part to draft — is setting out in words what the invention is. This is called the “patent claim.” In essence, the patent claims explain the invention in ordinary words. It is called a “claim” because the Patent Act requires that the applicant “shall claim” and describe the “subject matter” of the invention. From the claims, the USPTO can determine if the invention is patentable.

Any given patent application can have many claims. The USPTO has specific rules on how claims are to be drafted and formatted. For example, each claim is to be provided on a separate sheet. Each claim should also have three parts: a preamble, a transitional phrase and the claim body. A preamble is just a word or a few words giving context for the claimed invention. Examples might be: “a digging device” or “a headgear apparatus” (as in the example below). Examples of transitional phrases include:

• “Comprising”
• “Consisting essentially of”
• “Consisting of”
• And other words or phrases

The claim body describes and defines the invention such as structure and/or acts and/or parts in clear, full and concise terms. See examples below.

Drafting patent claims is complex and takes experience and skill. The scope of the patent protection is limited by the claim or claims as they are written in the patent application. If the claim(s) are drafted too narrowly, then the patent protections are less broad than they could be. This gives competitors the opportunity to “design around” the patent and market a similar product without infringing on the patent. But, if the claim(s) are too broad, then there is a risk that the patent will be denied because the proposed patent is covered by prior art or previous patents.

Generally, the USPTO allows two types of patent claims — independent and dependent claims. An independent claim is one that, as drafted, has all the limitations to fully define the invention. All patent applications have at least one independent claim. By contrast, a dependent claim is a claim that refers to a previous claim set forth in the application. A dependent claim must further limit the independent claim.

The USPTO provides examples of independent and dependent claims from a patent application for a multiple component headgear system (a visor and eye shield secured by a headband that wraps around the head). See here at pp. 18ff. Here are three of the USPTO’s examples:

Claim 1: Independent claim —

1. A headgear apparatus comprising:

a headband member having a frontal portion;

a visor member removably secured to said frontal portion of said headband; and

an eye shield member removably secured to said frontal portion of said headband.

Claim 2: Dependent claim —

2. A headgear apparatus as in claim 1, wherein said eye shield member is adjustable with respect to said headband member.

Claim 3: Additional dependent claim —

3. A headgear apparatus as in claim 1, wherein said headband member is made of neoprene fabric.

Notice how each dependent claim refers to the independent claim. And, as required, each dependent claim adds further limits to the independent claim.

Contact Revision Legal

For more information or if you have an invention or design that you want to patent, contact the patent lawyers at Revision Legal at 231-714-0100.

Why Claim Scope Is the Most Consequential Decision in Patent Prosecution

The commercial value of a patent is largely determined by the scope of its claims. Broad independent claims provide wide protection and are harder for competitors to design around; narrow claims are easier to obtain but provide thinner protection. Experienced patent attorneys draft independent claims at multiple levels of generality — a broad lead claim, a medium-scope alternative, and a narrower fallback — so that if the examiner rejects the broadest claim, the applicant can argue for a narrower scope rather than losing the application entirely. Prosecution history estoppel adds another dimension: if an applicant narrows a claim during prosecution to overcome a prior art rejection, the doctrine may bar the applicant from later arguing in litigation that the patent covers the surrendered subject matter under the doctrine of equivalents.

Dependent Claims as a Litigation Asset

Dependent claims serve important strategic functions in patent litigation. In an infringement case, a patent owner who proves infringement of a dependent claim has, by definition, also proven infringement of the independent claim from which it depends — because the dependent claim incorporates all elements of the independent claim and adds more. Dependent claims also provide invalidity insurance: even if the broadest independent claim is invalidated in post-grant proceedings, narrower dependent claims may survive. An infringer who successfully challenges an independent claim may still find that a dependent claim covers the accused product and remains valid.

Method Claims vs. Apparatus Claims

Patent applications for inventions that can be described both as a device and as a method of using it often include both apparatus claims and method claims. An apparatus claim is infringed by making, selling, offering for sale, or importing the claimed device. A method claim is infringed by performing the claimed steps — this catches entities that use the invention in a process even if they do not manufacture or sell a device covered by an apparatus claim. For manufacturing processes, software algorithms, and business methods, method claims may be the primary vehicle for protection.

The Transitional Phrase: Comprising, Consisting Of, and Consisting Essentially Of

The transitional phrase in a patent claim is legally significant. “Comprising” is open-ended — a product that contains all claimed elements plus additional elements still infringes. “Consisting of” is closed — only a product with exactly the claimed elements, and nothing more, infringes. “Consisting essentially of” is intermediate — it allows additional elements only if they do not materially affect the basic and novel characteristics. Choosing the wrong transitional phrase can either underprotect the invention or create validity problems by claiming too broadly. Contact the patent lawyers at Revision Legal at 231-714-0100 to discuss how to structure the claims in your patent application for maximum protection.