Patent claims are the most important part of a patent application, for they define the invention for which the Patent Office has granted protection. Patent claims identify what the patent does and does not cover.
Generally, claims are of two types – independent claims and dependent claims. Independent claims are ‘stand alone’ broad claims that do not bear reference to any other claim and contain all the essential elements necessary to define the invention. Dependent claims are claims that take precedence from an earlier claim (including independent claims) and limit their scope. Dependent claims either further define the earlier claim or contain additional non-essential features that may not have been included in the independent claim. The scope of dependent claims is therefore narrower than the scope of the earlier claim from which it takes precedence.
One dependent claim may take precedence from one or more earlier claims. When it takes precedence from one claim, it is known as a single dependent claim, whereas if it takes precedence from more than one claim, it is referred to as a multiple dependent claim. Any dependent claim that refers to more than one claim, i.e., a multiple dependent claim, shall refer to such other claims in the alternative only. This is because, for any given embodiment, a multiple dependent claim does not contain all the limitations of all the alternative claims to which it refers, but rather contains only those limitations of the particular claim referred to for the embodiment under consideration. A multiple dependent claim must therefore be considered in the same manner as a plurality of single dependent claims. Some examples of the acceptable and unacceptable syntactical structure of multiple dependent claims are shown in Table 1 and Table 2.
Table 1: Examples of Acceptable Dependent Claims
|S. No.||Claim||Acceptable Multiple dependent Claims|
|1.||Claim 5||A gadget as claimed in claims 3 or 4, further comprising —|
|2.||Claim 5||A gadget as claimed in any one of the preceding claims, in which –|
|3.||Claim 5||A gadget as claimed in any one of claims 1, 2, and 3, in which —|
|4.||Claim 3||A gadget as claimed in either claim 1 or claim 2, comprising –|
|5.||Claim 8||A gadget as claimed in one of claims 4-7, in which|
Table 2: Examples of Unacceptable Dependent Claims
|S. No.||Claim||Improper (Unacceptable) Dependent Claims|
|1.||Claim 9||A gadget according to claims 1-3, in which —|
|2.||Claim 9||A gadget as in claims 1 or 2 and 7 or 8, which —|
|3.||Claim 6||A gadget as in the preceding claims in which|
|4.||Claim 6||A gadget as in claims 1, 2, 3, 4 and/or 5, in which|
A common question that arises while drafting is whether a dependent claim can refer to or take precedence from a multiple dependent claim. This answer to this lies in the manner in which the claim has been made dependent on the multiple dependent claim. If the dependent claim is drafted as a single dependent claim on a multiple dependent claim, the dependent claim may be acceptable. However, if the dependent claim is drafted as a multiple dependent claim, i.e. a multiple dependent claim on another multiple dependent claim, it would not be acceptable.
When drafting dependent claims under the Patent Convention Treaty (PCT), guidance is provided in Rule 6.4 of the PCT guidelines which clearly prescribes that multiple dependent claims shall not serve as a basis for any other multiple dependent claim. Similar limitations can also be found at § 608.01(n) of the United States’ Manual of Patent Examining Procedure.
Patent law in India, unlike in the US and under the PCT, does not provide much clarity on the acceptance of the multiple dependent claims on another multiple dependent claim. The only requirement defined in respect of drafting claims in India, which is applicable to all inventions, is found in Section 10(4)(c) of the Patents Act, 1970 where it is stated that ‘Every complete specification shall— ….. (c) end with a claim or claims defining the scope of the invention for which protection is claimed.’ Also, the Manual for Patent Office Practice and Procedure of India, at 05.03.17(k), states that “[e]ach claim should be complete so that it covers the inventive feature and enough elements around it to put the invention in the proper context.” This indicates that the claims must be definitive and clearly define the subject matter for which protection is sought. By corollary, it can be argued that since a multiple dependent claim does not contain all the limitations of all the alternative claims to which it refers, the said claim cannot serve as the basis for another multiple dependent claim without causing undue confusion in determining how many prior claims are actually referred to.
In India, multiple dependent claims are treated as single dependent claims for determining the number of claims in a patent application. Given this procedural context, drafting multiple dependent claims for Indian patent applications would be a cost effective approach. As per Indian patent law, excess claim fee is payable for the claims over and above 10 claims. On the contrary, in the US, multiple dependent claims are not considered as single dependent claims for the purpose of calculating fees; rather, a multiple dependent claim is considered to be that number of dependent claims to which it refers.