10 Common Patent Claim Drafting Mistakes to Avoid

Drafting a patent application is a complex task that involves dealing with several critical components of the patent application. If one must ask any patent attorney about the crucial aspect of a patent draft, the answer will always be “the claims”. Even the simplest of mistakes in claims can pose risk to a patent application. In light of this, the following article highlights some potential pitfalls to avoid while drafting patent claims.

What are Patent Claims?

Claims act as a boundary of patents – defining the patentee’s monopoly over the invention. They should inform the public of the limits of the monopoly asserted during the life of a patent. It helps others to know which features can/cannot be safely used or manufactured without a license. That is why it is always advisable to identify or avoid claim drafting mistakes – whether stylistic or grammatical – before they put the patent owner at a disadvantage.

10 Pitfalls that Drafters Must Avoid While Drafting Claims

Figure: 10 Common Mistakes to Avoid When Drafting Patent Claims

1. Violations of Claim Grammar: The legal and customary requirement of the claim structure stipulates that “a claim is a single sentence”. The structure should begin with a capital letter and have a period in the end – and those must be the only capital letters or periods in the claim. In addition, many patent drafters break the claim into subsections ending up with semicolons. The second last subsection usually ought to have an “and” at the end.

Furthermore, when an element or a part is introduced in the claim for the first time, it should be preceded by the indefinite article (“a” or “an”). Thereafter, the element or part is preceded by a definite article (“the”) or by (“said”).

2. Claiming a Result: Inventors secure patent grants on the basis of the invention and not its result. This is because they cannot claim a result but only the apparatus or method that accomplishes that result. 

3. Focusing Only on the Independent Claim: Drafters invest so much time and effort in writing the independent claims that they end up spending lesser time on formulating dependent claims. While that may be necessary, it is important to focus on dependent claims adequately as they have their unique purpose. When independent claims get rejected, drafters insert the limitations of the dependent claim into the independent claim.

4. Avoid Use of “Means-Plus-Function” Language: The means-plus-function language adds limitations and narrows the claims by excluding all the equivalents that are not known at the time of disclosure. That is why it is preferred and recommended to avoid “means-plus-function language”. However, if one still wants to use it, one must make sure to list every possible variation of the “means” into the specifications.

5. Claiming too Broadly: Claims should be broad, however, there is a limit. Too broad claims apply to other devices or methods that fall under prior-art. For example, let’s consider an invention that is an improvement in wrench using a rack-and-pinion arrangement for adjusting the jaws. It might seem broader to claim “a rack and pinion” rather than “a wrench comprising a jaw with a rack, and a rotatable pinion gear engaged with the rack.” But this will be counterproductive.

Our invention is not a rack and pinion. By claiming it, one has selected a claim broader than one is entitled to. The examiner may cite automotive steering against the invention, and that will be the right ground for rejection. Instead, claiming a wrench using the rack and pinion will narrow down the focus to tools, and the claim will have higher chances of approval.

6. Inconsistent Terminology: The claims should always be drafted consistently. Claims containing inconsistent claim terms can result in unintended consequences during patent litigation. For example, if a motor has been recited in the claims, the drafter should not refer to ‘the motor’ with different nomenclature.

Similarly, it is also advisable not to describe additional details of an element while referring to it. For example, if “a gear” has been recited, it would be improper to refer back to it as “the plastic gear” or “the drive gear”. This will add an “indirect limitation” on the claimed element.

7. Wrong Choice of Transition Phrase: The transition phrase is used between the preamble and the body of the claim. Each word has a special meaning that can severely affect the claims if used wrongly. For example: “Comprising” or “Comprises” are open-ended transition phrases, and include the following elements without excluding others. It is a preferred transitional word and is recommended for use in most cases.

8. Avoid Using Trademarks in Claims: It is advised to use generic names rather than trademarks in claims. Trademarks only indicate a particular product or service and not the description of the product. In addition, the product made under the given trademark may change over time, but the generic description of the product remains the same.

9. Overuse of Adjectives: Overuse of adjectives tends to over-describe the invention, restricting the scope of the claims. Therefore, unnecessary adjectives must be avoided while drafting claims.

10. Keywords to Avoid in the Claims: The use of words, such as, exactly, can, could, must, might, prior-art, large, small, heavy, above, below, right, left, etc., should be avoided in the claims as a best practice.


Claims represent “the heart of the patent application”. That is why the nuanced task of drafting patent claims should be handled by experienced and qualified professionals. The claims, when drafted accurately, adequately define the scope of protection provided to an invention.

Sagacious IP’s patent drafting services are designed to provide end-to-end patent drafting support to businesses. Our experienced team of patent draftsmen ensures the broadest possible coverage to prevent third parties from circumventing claims of a patent application.

  • Yojit Bhugra (Engineering Drafting) and the Editorial Team

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