Quote from Martin Schweiger on September 25, 2018, 4:07 am
Short answer:
Although you cannot amend the claims of a German Utility model as you can amend the claims of a patent in many jurisdictions, it is possible to voluntarily limit the scope of protection of a German utility model.
This is not explicitly stated in the German Utility Model Act, but there is relevant German case law supporting that.
More detailed answer:
Different from the patent laws of many countries there are no provisions for a post-grant restriction of utility model claims.
However, there is German case law which is in favor of amending utility model claims after registration, see for example BGH in BGHZ 137, 60 = GRUR 1998, 910, 912 "Scherbeneis" and BPatG in BPatGE 34, 58, 62 = BIPMZ 1994, 159
The filing of new claims into the official file of a utility model does not cause an immediate change of the subject matter of the utility model, but it can, in general, be seen as a remedy in order to avoid formal invalidation proceedings of the utility model in its broader scope. If such invalidation proceedings are nevertheless started by a third party, the examination will still be based on the claims of the utility model in its registered form, and not on any claims filed after grant.
The limitation is done such that the new claims are included in the official file at the German Patent and Trademark Office. There is no examination of the new claims. The German Patent and Trademark Office only issues a confirmation of receipt with a comment that no examination is taking place.
The filing of a limited set of claims after registration will be considered as a declaration that the utility model owner will only assert his rights within the scope of the limited set of claims (see BPatGE 11, 96, 100, 101). This self-limitation will take effect from the time of filing the limited set of claims (see BPatGE 11, 88; 11, 96).
To summarize my answer: while filing new claims after grant may save time and money during invalidation or infringement proceedings, a voluntary limitation of utility model claims after grant does not protect the utility model against any invalidity proceedings.
In a sideline only, it is not possible to amend the description or the drawings of a utility model after registration, see BPatG 5 W 443/63 - "Folienkapsel".