With the amended examination Guidelines by CNIPA effective from November 2019, a grandchild (or further) divisional application filed as a result of receiving a non-unity objection to a child divisional application shall be filed within two months from receiving the notification of grant for the child divisional.
In the case of filing a grandchild divisional based on a child divisional, the GL provides that the term shall be calculated based on the original application, which is the grandparent application. However this actually relates to the situation of the applicant voluntarily filing a grandchild divisional. As for filing a grandchild divisional upon receiving a non-unity objection with regard to the child divisional, the GL provides that: if the Examiner has issued a communication on the issue of non-unity with regard to the child divisional, the two months term as specified above is not applicable. In fact, the Guidelines was silent about a specific term for this scenario.
This seems to have created a chance of filing a grandchild divisional based on a child divisional received a non-unity objection at any time. Actually Intel Corp. did file a grandchild divisional (CN201210161092.2 filed on May 14, 2012) based on a child divisional (CN02126161.X filed on July 19, 2002), which was granted on June 29, 2016, nearly 19 months after expiry of twenty years from the filing date of the parent application (CN95197430.0 filed on December 1, 1995).
2. Amended Guidelines
The amended Guidelines explicitly provide that in filing a grandchild divisional as a result of receiving an objection to non-unity of a child divisional, the term for filing shall be calculated as within two months from receiving the notification of grant for the child divisional. This has resolved the issue of filing a grandchild divisional application in view of a received non-unity objection at any time, even years after neither the original application nor the child divisional is pending.
As for voluntarily filing a grandchild divisional by the applicant, the time limit for filing is still calculated based on the grandparent application. Considering of the examination period, if the grandchild divisional is filed after examination for the child divisional has started, it is quite unlikely that the grandparent application is still pending at this time. This essentially means filing a grandchild divisional voluntarily is not viable.
The following graph explains the terms in a more straightforward manner.
In view of the above, if the applicant seeks to file several generations of divisional such that the invention may be kept pending for a longer period of time, the most practical approach would be always keeping claims not conforming to unity requirement such that a non-unity objection will be issued. This can ensure that a further divisional is possible.