Within the framework of Art. 123(2) and Art. 82, Rule 137(5) should be construed as permitting any limitation of searched subject-matter which is unitary with the originally claimed subject-matter, irrespective of whether the technical feature(s) used for the limitation has/have been searched.
Thus, the addition to a claim of a technical feature which further defines an element that was already a feature of the original main claim or makes a contribution to the effect(s) of the features of the originally claimed invention(s) and which was expressly not searched but was disclosed in the context of the invention in the application as filed (usually in the description) will not result in an amended claim lacking a single general inventive concept with respect to the originally claimed invention(s). Consequently no objection under Rule 137(5) should be raised in these circumstances, even though an additional search may be required (see C‑IV, 7.2).
If amended claims are directed to subject-matter which has not been searched because it only appeared in the description (and the Search Division did not find it appropriate to extend the search to this subject-matter, see B‑III, 3.5) and which does not combine with the originally claimed and searched invention or group of inventions to form a single general inventive concept, such amendments are not admissible.
An objection under Rule 137(5) will normally arise if the applicant attempts to replace a technical feature contained in a claim with a different technical feature taken from the description.
An objection under Rule 137(5) would also arise if a technical feature taken from the description which has an effect unrelated to the effect(s) of the features of the originally claimed invention(s) were added to a claim. Such a situation could arise when the subject-matter originally claimed has to be amended in view of a novelty or inventive step objection resulting from a broad claim formulation and when the original broad claim is restricted by the addition of a technical feature from the description which had an effect not related to the effects of the features already present in the original set of claims, such that there is lack of unity between the new limited claim and the claims originally present.
The situation described above is different from amendments corresponding to an invention originally claimed but not searched under Rule 64 or Rule 164(1) or Rule 164(2), which are dealt with in H‑II, 7.2.
For Euro-PCT applications where the EPO acted as ISA or as SISA, the Examining Division has to issue an invitation under Rule 164(2) for unsearched inventions contained in the application documents which are to serve as the basis for examination upon expiry of the six-month time limit set in the communication under Rule 161 or Rule 162, even if these inventions were imported from the description (see C‑III, 2.3).