Restriction requirement practice in the US can often be confusing to non-US IP counsel accustomed to unity of invention standards, as well as to applicants who want to ensure that their patent covers different variations of their invention. This primer covers the basics of US restriction practice and offers some considerations when responding to a restriction requirement.


What is a Restriction Requirement?

A U.S. patent application may, and often does, describe multiple inventions or different embodiments of the same invention. Yet, when different inventions or embodiments are encompassed by the claims, an examiner may issue a restriction requirement for the applicant to choose which one to pursue. The rationale is that examining several different inventions and features places an undue burden on the examiner.

All in all, the restriction requirement is an administrative procedure that requires the applicant to choose a single invention when two or more inventions or embodiments are present in the same application.

Restriction requirements may arise in U.S. patent applications that are first filed in the U.S. or that claim priority to a domestic or foreign patent application. An international patent application entering the U.S. as a national stage application (under 35 U.S.C. § 371) is examined under the unity of invention standard. The different standard and terminology used for restriction requirements can lead to confusion, particularly for non-US applicants who are accustomed to unity of invention.

U.S. patent law authorizes an examiner to require a restriction when two or more “independent and distinct” inventions are claimed in one patent application. In practice, restriction requirements are issued when 1) the claims describe two or more inventions that are independent or distinct and 2) a serious burden will result if restriction is not required. MPEP § 803. Both conditions must be met. Independent inventions are those that have no disclosed relationship and that are unconnected in design, operation, and effect. A common example is when an apparatus and a process are separately claimed, and the apparatus cannot be used in the process. Distinct inventions are inventions for which one is novel and non-obvious (i.e., patentable) over the other.

A restriction requirement typically identifies two or more groups of claims believed to be independent or distinct and requires the applicant to choose one. Restriction requirements may also include, or an examiner may separately issue, a requirement to elect a species. These arise when there is a claim directed to a generic invention (genus) and disclosure of or claims to multiple patentably distinct species within the genus. Rather than the examiner identifying groups of claims, an election of species might require an election between species shown in the figures or species listed in a Markush group. In response, the applicant must elect a species, identify which claims read on the elected species, and identify which claims are generic to all species.

The applicant can optionally argue against (or traverse) a restriction requirement. However, any response must include an election of one group of claims and/or species to pursue whether or not it also includes arguments. If the restriction is maintained, non-elected claims may be cancelled by the applicant or the applicant may choose to keep them pending in the application as withdrawn.


Considerations When Responding to Restriction Requirements

Careful consideration should be taken when choosing which claims to pursue in response to restriction requirement and whether to traverse the restriction.

Restrictions generally arise before examination and, once an election is made, the applicant cannot shift prosecution to a different invention as a matter of right. This means that if the elected invention is found to be in the prior art during examination, the applicant generally needs to file a new application to pursue the non-elected claims.

When making an election, the applicant should consider which group is most pertinent to their commercial product and which group has the strongest claims for purposes of patentability. The number of claims and breadth of the subject matter in each group of claims, and the extent of related disclosure in the specification and drawings, should also be considered. Having more claims and subject matter to fall back on expands your options if amendments become necessary during prosecution.

Grounds for traversing a restriction requirement include: that the inventions are not independent or distinct, or that no serious burden will result for the examiner if the restriction is withdrawn. However, arguing that the two or more inventions are not distinct can have negative consequences. The restriction requirement will likely be withdrawn, but the applicant’s arguments can be used against them as an admission against patentability. For example, if just one of the identified inventions is later found to be in the prior art, the examiner will conclude that the other inventions are obvious because the applicant admitted they are not patentable over one another.

Non-elected claims may be cancelled by the applicant or the applicant may choose to keep them in the application as withdrawn. Keeping the claims as withdrawn is advantageous, particularly when the withdrawn claims are dependent on (or share patentable subject matter with) an elected claim. These claims may be eligible for rejoinder once an elected claim is allowed.

When non-elected claims are cancelled or rejoinder is not permitted, those claims may be pursued in a divisional application at any time before issuance of the parent application. When this occurs, examiners are not permitted to issue a double patent rejection in view of the parent application since an examiner already found the claims to be drawn to independent or distinct inventions.

As in any case, when faced with a restriction requirement, consult with your US patent attorney for advice as to how best to respond to ensure that you elect the best set of claims to cover your invention.

Ben Lehberger

Image credits: Photo by Pressfoto on Freepik

This article is for informational purposes, is not intended to constitute legal advice, and may be considered advertising under applicable state laws. The opinions expressed in this article are those of the author only and are not necessarily shared by Dilworth IP, its other attorneys, agents, or staff, or its clients.