The international application shall relate to one invention only or to a group of inventions so linked as to form a single general inventive concept (“requirement of unity of invention”).

Where a group of inventions is claimed in one and the same international application, the requirement of unity of invention referred to in Rule 13.1 shall be fulfilled only when there is a technical relationship among those inventions involving one or more of the same or corresponding special technical features. The expression “special technical features” shall mean those technical features that define a contribution which each of the claimed inventions, considered as a whole, makes over the prior art.

The determination whether a group of inventions is so linked as to form a single general inventive concept shall be made without regard to whether the inventions are claimed in separate claims or as alternatives within a single claim.

Subject to Rule 13.1, it shall be permitted to include in the same international application a reasonable number of dependent claims, claiming specific forms of the invention claimed in an independent claim, even where the features of any dependent claim could be considered as constituting in themselves an invention.

Any designated State in which the grant of a utility model is sought on the basis of an international application may, instead of Rules 13.1 to 13.4, apply in respect of the matters regulated in those Rules the provisions of its national law concerning utility models once the processing of the international application has started in that State, provided that the applicant shall be allowed at least two months from the expiration of the time limit applicable under Article 22 to adapt his application to the requirements of the said provisions of the national law.

The invitation to pay additional fees provided for in Article 17(3)(a) shall:

(i) specify the reasons for which the international application is not considered as complying with the requirement of unity of invention;
(ii) invite the applicant to pay the additional fees within one month from the date of the invitation, and indicate the amount of those fees to be paid; and
(iii) invite the applicant to pay, where applicable, the protest fee referred to in Rule 40.2(e) within one month from the date of the invitation, and indicate the amount to be paid.

(a) The amount of the additional fees due for searching under Article 17(3)(a) shall be determined by the competent International Searching Authority.
(b) The additional fees due for searching under Article 17(3)(a) shall be payable direct to the International Searching Authority.
(c) Any applicant may pay the additional fees under protest, that is, accompanied by a reasoned statement to the effect that the international application complies with the requirement of unity of invention or that the amount of the required additional fees is excessive. Such protest shall be examined by a review body constituted in the framework of the International Searching Authority, which, to the extent that it finds the protest justified, shall order the total or partial reimbursement to the applicant of the additional fees. On the request of the applicant, the text of both the protest and the decision thereon shall be notified to the designated Offices together with the international search report. The applicant shall submit any translation thereof with the furnishing of the translation of the international application required under Article 22.
(d) The membership of the review body referred to in paragraph (c) may include, but shall not be limited to, the person who made the decision which is the subject of the protest.
(e) The examination of a protest referred to in paragraph (c) may be subjected by the International Searching Authority to the payment to it, for its own benefit, of a protest fee. Where the applicant has not, within the time limit under Rule 40.1(iii), paid any required protest fee, the protest shall be considered not to have been made and the International Searching Authority shall so declare. The protest fee shall be refunded to the applicant where the review body referred to in paragraph (c) finds that the protest was entirely justified.

(a) An international and a national stage application shall relate to one invention only or to a group of inventions so linked as to form a single general inventive concept (“requirement of unity of invention”). Where a group of inventions is claimed in an application, the requirement of unity of invention shall be fulfilled only when there is a technical relationship among those inventions involving one or more of the same or corresponding special technical features. The expression “special technical features” shall mean those technical features that define a contribution which each of the claimed inventions, considered as a whole, makes over the prior art.
(b) An international or a national stage application containing claims to different categories of invention will be considered to have unity of invention if the claims are drawn only to one of the following combinations of categories:

(1) A product and a process specially adapted for the manufacture of said product; or
(2) A product and a process of use of said product; or
(3) A product, a process specially adapted for the manufacture of the said product, and a use of the said product; or
(4) A process and an apparatus or means specifically designed for carrying out the said process; or
(5) A product, a process specially adapted for the manufacture of the said product, and an apparatus or means specifically designed for carrying out the said process.

(c) If an application contains claims to more or less than one of the combinations of categories of invention set forth in paragraph (b) of this section, unity of invention might not be present.
(d) If multiple products, processes of manufacture or uses are claimed, the first invention of the category first mentioned in the claims of the application and the first recited invention of each of the other categories related thereto will be considered as the main invention in the claims, see PCT Article 17(3)(a) and § 1.476(c).
(e) The determination whether a group of inventions is so linked as to form a single general inventive concept shall be made without regard to whether the inventions are claimed in separate claims or as alternatives within a single claim.