[6] Canadian practice differs significantly from U.S. practice on this front, in that, once a double patenting objection is encountered, there is no statutory provision for terminal disclaimer in the Canadian Patent Act.
Divisional applications filed voluntarily may be susceptible to attacks on the grounds of double patenting.
However, where a divisional is forced by the Patent Office during prosecution (i.e. to overcome a unity of invention objection), the Supreme Court of Canada has indicated that such an application and its parent should not be open to double patenting challenges.
"[10][11] However, in June 2007, the Enlarged Board of Appeal of the EPO in cases G 1/05 and G 1/06 accepted, by way of obiter dictum,[12] that The Board therefore accepted the practice of the EPO "that amendments to a divisional application are objected to and refused when the amended divisional application claims the same subject-matter as a pending parent application or a granted parent patent.
[15] The Board notably based its reasoning on the wording of Article 60 EPC according to which "[the] right to a European patent shall belong to the inventor or his successor in title".
[16] In other words, The Board in case T 307/03 explicitly disagreed with the apparent conclusion of earlier decision T 587/98 that there would be no basis in the EPC prohibiting "conflicting claims".
[18] The claim was therefore objected for double patenting and the main request was not allowed into the proceedings.
In case T 1391/07 (November 2008), the Board 3.4.02 held that a double patenting objection did not arise when the claims of two applications only overlap, in such a manner that the scope of protection sought by the invention claimed in the divisional application was notionally different from the scope of protection conferred by the claims of the granted parent patent.
[22] In other words, the Board held that when there was a partial overlap in the respective scopes of protection: this did not lead to a double patenting objection.
[39] This is caused primarily by the abusive practice of restriction requirement, when patent examiners demand from applicants splitting each patent application into numerous divisionals, each of those requiring payment of separate search, examination and maintenance fees.
The second rejection type precludes what is referred to as "obviousness-type" or "nonstatutory" double patenting.
The US Congress finally addressed this problem in § 121 of the Patent Act of 1952 by adding a provision that, when an inventor files a divisional application in response to a restriction requirement by an examiner, one restricted application “shall not be used as a reference” against the other.
If the claims in a divisional application are amended later so that they "are not consonant with the restriction requirement made by the examiner", the patentee loses his immunity against double-patenting accusation (see Symbol Technologies, Inc. v. Opticon, Inc., 935 F.2d 1569, 19 USPQ2d 1241 (Fed.
In order for the consonance to exist, the line of demarcation between the independent and distinct inventions identified by the examiner in the requirement for restriction must be maintained.