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802    Basis for Practice in Statute and Rules [R-08.2012]

The basis for restriction and double patenting practices is found in the following statute and rules:

35 U.S.C. 121   Divisional applications.

If two or more independent and distinct inventions are claimed in one application, the Director may require the application to be restricted to one of the inventions. If the other invention is made the subject of a divisional application which complies with the requirements of section 120 of this title it shall be entitled to the benefit of the filing date of the original application. A patent issuing on an application with respect to which a requirement for restriction under this section has been made, or on an application filed as a result of such a requirement, shall not be used as a reference either in the Patent and Trademark Office or in the courts against a divisional application or against the original application or any patent issued on either of them, if the divisional application is filed before the issuance of the patent on the other application. If a divisional application is directed solely to subject matter described and claimed in the original application as filed, the Director may dispense with signing and execution by the inventor. The validity of a patent shall not be questioned for failure of the Director to require the application to be restricted to one invention.

37 C.F.R. 1.141   Different inventions in one national application.

(a) Two or more independent and distinct inventions may not be claimed in one national application, except that more than one species of an invention, not to exceed a reasonable number, may be specifically claimed in different claims in one national application, provided the application also includes an allowable claim generic to all the claimed species and all the claims to species in excess of one are written in dependent form (§ 1.75) or otherwise include all the limitations of the generic claim.

(b) Where claims to all three categories, product, process of making, and process of use, are included in a national application, a three way requirement for restriction can only be made where the process of making is distinct from the product. If the process of making and the product are not distinct, the process of using may be joined with the claims directed to the product and the process of making the product even though a showing of distinctness between the product and process of using the product can be made.

37 C.F.R. 1.142   Requirement for restriction.

  • (a) If two or more independent and distinct inventions are claimed in a single application, the examiner in an Office action will require the applicant in the reply to that action to elect an invention to which the claims will be restricted, this official action being called a requirement for restriction (also known as a requirement for division). Such requirement will normally be made before any action on the merits; however, it may be made at any time before final action.
  • (b) Claims to the invention or inventions not elected, if not canceled, are nevertheless withdrawn from further consideration by the examiner by the election, subject however to reinstatement in the event the requirement for restriction is withdrawn or overruled.

The pertinent Patent Cooperation Treaty (PCT) Articles and Rules are cited and discussed in Chapter 1800. Sections 1850, 1875, and 1893.03(d) should be consulted for discussions on unity of invention:

  • (A) before the International Searching Authority;
  • (B) before the International Preliminary Examining Authority; and
  • (C) in the National Stage under 35 U.S.C. 371.

802.01   Meaning of “Independent” and “Distinct” [R-08.2012]

35 U.S.C. 121 quoted in the preceding section states that the Director may require restriction if two or more “independent and distinct” inventions are claimed in one application. In 37 CFR 1.141, the statement is made that two or more “independent and distinct inventions” may not be claimed in one application.

This raises the question of the inventions as between which the Director may require restriction. This, in turn, depends on the construction of the expression “independent and distinct” inventions.

“Independent”, of course, means not dependent, or unrelated. If “distinct” means the same thing, then its use in the statute and in the rule is redundant. If “distinct” means something different, then the question arises as to what the difference in meaning between these two words may be. The hearings before the committees of Congress considering the codification of the patent laws indicate that 35 U.S.C. 121: “enacts as law existing practice with respect to division, at the same time introducing a number of changes.”

The report on the hearings does not mention as a change that is introduced, the inventions between which the Director may properly require division.

The term “independent” as already pointed out, means not dependent, or unrelated. A large number of inventions between which, prior to the 1952 Act, division had been proper, are dependent inventions, such as, for example, combination and a subcombination thereof; as process and apparatus used in the practice of the process; as composition and the process in which the composition is used; as process and the product made by such process, etc. If section 121 of the 1952 Act were intended to direct the Director never to approve division between dependent inventions, the word “independent” would clearly have been used alone. If the Director has authority or discretion to restrict independent inventions only, then restriction would be improper as between dependent inventions, e.g., the examples used for purpose of illustration above. Such was clearly not the intent of Congress. Nothing in the language of the statute and nothing in the hearings of the committees indicate any intent to change the substantive law on this subject. On the contrary, joinder of the term “distinct” with the term “independent”, indicates lack of such intent. The law has long been established that dependent inventions (frequently termed related inventions) such as used for illustration above may be properly divided if they are, in fact, “distinct” inventions, even though dependent.


The term “independent” (i.e., unrelated) means that there is no disclosed relationship between the two or more inventions claimed, that is, they are unconnected in design, operation, and effect. For example, a process and an apparatus incapable of being used in practicing the process are independent inventions. See also MPEP § 806.06 and § 808.01.


Two or more inventions are related (i.e., not independent) if they are disclosed as connected in at least one of design (e.g., structure or method of manufacture), operation (e.g., function or method of use), or effect. Examples of related inventions include combination and part (subcombination) thereof, process and apparatus for its practice, process and product made, etc. In this definition the term related is used as an alternative for dependent in referring to inventions other than independent inventions.

Related inventions are distinct if the inventions as claimed are not connected in at least one of design, operation, or effect (e.g., can be made by, or used in, a materially different process) and wherein at least one invention is PATENTABLE (novel and nonobvious) OVER THE OTHER (though they may each be unpatentable over the prior art). See MPEP § 806.05(c) (combination and subcombination) and § 806.05(j) (related products or related processes) for examples of when a two-way test is required for distinctness.

It is further noted that the terms “independent” and “distinct” are used in decisions with varying meanings. All decisions should be read carefully to determine the meaning intended.

802.02   Definition of Restriction [R-08.2012]

Restriction is the practice of requiring an applicant to elect a single claimed invention (e.g., a combination or subcombination invention, a product or process invention, a species within a genus) for examination when two or more independent inventions and/or two or more distinct inventions are claimed in an application.



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Last Modified: 03/27/2014 10:10:36