US patent practice concerning multiple dependent claims is partially addressed by 35 USC §112(e). That subsection of the statute currently reads, in part, “A claim in multiple dependent form [i] shall contain a reference, in the alternative only, to more than one claim previously set forth and [ii] then specify a further limitation of the subject matter claimed. [iii] A multiple dependent claim shall not serve as a basis for any other multiple dependent claim.” Let’s break that down.
Regarding [i], a multiple dependent claim must reference claims in the alternative only. As stated in MPEP 608.01(n) I, “A machine according to claims 3 and 4, further comprising —” is improper, because it depends from Claims 3 and 4, not 3 or 4. Likewise, a claim reciting “The composition of claim 1, comprising the compound of claim 2, wherein –” is improper, because it depends from Claims 1 and 2.
As to [ii], this portion follows an analogous requirement for single dependent claims in 35 USC §112(d). For example, if independent Claim 1 is directed to an apparatus including A, B, and C, then Claim 2 cannot read, “The apparatus of Claim 1, wherein C is replaced with D.” MPEP 608.01(n) III.
In the particular context of multiple dependent claims, a European-style claim set might fail to limit preceding claims. For example, a European-style claim set might direct Claims 1-10 to a method. Then, Claim 11 might recite, “An apparatus comprising means for performing the method of any of Claims 1-10.”
Under US practice, it could be argued this claim does not limit the method. Specifically, although the claimed apparatus can implement the method, the apparatus does not necessarily implement the method at all times (e.g., while the apparatus is off). So, Claim 11 can be infringed without infringing the method and, thus, is improper. (Of course, Claim 11 would be improper, even if it depended only from Claim 1.)
Finally, with regard to [iii], US practice permits multiple dependent claims, but not additional multiple dependent claims depending therefrom. (We believe this rule is also implemented in China.) For example, assume Claim 3 recites, “The apparatus of any of Claims 1-2, wherein –.” Then, Claim 4 cannot recite, “The apparatus of any of Claims 1-3, wherein –.”
A future post will address multiple dependent claims in the context of preparing applications for US prosecution. In the interim, if we can assist the handling of multiple dependent claims, please contact us.