What is a restriction requirement in a patent application?
A restriction requirement is an Office action issued when a patent application claims two or more independent and distinct inventions, requiring the applicant to elect one invention for continued prosecution. The statutory authority is 35 U.S.C. § 121, which permits the Director to require restriction when a single application contains multiple independent and distinct inventions. 37 CFR 1.141 codifies the underlying rule that two or more independent and distinct inventions may not be claimed in one national application.
A restriction requirement typically arrives before the examiner reaches the merits of the claims, though the rules permit it at any time before final action.
The two-part test
Not every multi-invention application triggers a valid restriction requirement. To impose one, the examiner must satisfy both prongs of a two-part test: the inventions must be independent or distinct as claimed, and there would be a serious search and/or examination burden on the examiner if restriction is not required.
Part 1: Independent or distinct as claimed
The examiner compares actual claim language, not just the disclosure. Two standards apply:
Independent inventions have no disclosed relationship between them: they are unconnected in design, operation, and effect. Restriction between independent inventions is ordinarily proper because there is no technical reason to examine them together.
Distinct inventions are related in the disclosure but the inventions as claimed are not connected in at least one of design, operation, or effect, and at least one invention is patentable over the other. Distinctness requires both that the claimed inventions diverge in some structural or functional respect and that one has independent patentability over the other.
Part 2: Serious search or examination burden
Even when inventions are independent or distinct, the examiner must also show that examining all claims together would impose a serious search and/or examination burden. If the search and examination of all claims can be made without serious burden, the examiner must examine them on the merits even though they include claims to independent or distinct inventions.
An examiner establishes prima facie serious burden through separate patent classification, separate status in the prior art, different fields of search, or non-prior art issues under 35 U.S.C. §§ 101 or 112 affecting one invention but not another. An applicant can rebut this showing with evidence that the claimed inventions actually share a common search field.
Common restriction scenarios
MPEP § 806 identifies several common relationship categories and the conditions under which each pair is considered distinct.
| Relationship | Considered distinct when |
|---|---|
| Product and process of making | The process is not an obvious way to make the product and can make other products, or the product can be made by materially different processes |
| Product and process of using | The using process works with materially different products, or the product works in materially different using processes |
| Combination and subcombination | Two-way distinctness: the combination does not require the particulars of the subcombination for patentability, and the subcombination has independent utility |
| Independent inventions (no disclosed relationship) | By definition unconnected; restriction is ordinarily proper |
How to respond to a restriction requirement
The applicant must elect an invention to which the claims will be restricted. Two response paths are available.
Election with traverse
An applicant who disagrees with the restriction may contest it while simultaneously electing. Under 37 CFR 1.143, the response must request reconsideration and withdrawal or modification of the requirement, give the reasons therefor, and indicate a provisional election of one invention for prosecution in case the traverse fails. The reasons must distinctly and specifically point out the supposed errors in the restriction requirement.
If the examiner reconsiders and maintains the restriction, it becomes final in the next Office action and examination proceeds on the elected claims.
If the traverse ultimately fails and the restriction becomes final, the applicant may petition the Director under 37 CFR 1.144. The petition may be deferred until after final action on or allowance of claims to the elected invention, but must be filed not later than appeal.
Election without traverse
An applicant may elect without challenging the restriction. Electing without traverse, however, means the applicant has not retained the right to petition the restriction requirement. This is the faster path, but it permanently forecloses the petition remedy.
What happens to non-elected claims
Claims directed to non-elected inventions are withdrawn from further consideration by the examiner. They are not rejected on the merits; they are set aside pending a decision on the elected claims.
Two routes exist to protect the non-elected subject matter.
Divisional application. The applicant may file a separate divisional application directed to the non-elected invention. A divisional application is entitled to the benefit of the filing date of the original application. Crucially, a patent issuing on the original application may not be used as a prior art reference against the divisional application, provided the divisional was filed before the sibling patent issued.
Rejoinder. Non-elected withdrawn claims may be rejoined into the parent application if they depend from or otherwise require all the limitations of a claim that becomes allowable. Rejoinder is worth tracking because it can recover non-elected subject matter without a separate filing, as long as the elected claims eventually dominate the non-elected ones.
Practical notes for practitioners
Always traverse when the restriction appears improper. Electing without traverse forfeits the petition right permanently. If there is any colorable argument that the inventions share a common design, operation, or effect, or that the examiner's burden showing relies on mere classification labels without further analysis, preserve the petition right by traversing.
Scrutinize the examiner's reasoning. The MPEP requires examiners to provide reasons, not mere conclusions, for the independence or distinctness finding and for the burden analysis: a restriction requirement that states only a conclusion is inadequate. A deficient showing is itself a ground for traverse.
Watch the election language. Words used when characterizing each invention during election become part of the prosecution history. A narrow or poorly worded election response can create a record that limits claim scope even in the elected claims.
Time the divisional filing before the parent issues. The non-reference protection under 35 U.S.C. § 121 applies only if the divisional is on file before the parent patent issues. Once the parent issues, the protection window closes and the parent may potentially be cited against the divisional.