Relations Between Claim Preamble and Claim Limitations

Relations Between Claim Preamble and Claim Limitations

Pang Mingjuan

Patent Examination Cooperation (Beijing)

Center of the Patent office, CNIPA


  1. Analogy to Riddle and Answer


    In a patent claim, multiple technical features including “preamble” together constitute the technical solution covered by the “preamble.” The technical solution comprising so many technical features need to be summarized under a preamble. Hence, the “preamble” of the patent claim becomes an external expression of the “technical solution.” Therefore, it can be seen that the “preamble” itself is not the technical solution, but a “technical solution” is the substantive content of multiple technical features. Although patent system has been in practice for more than 30 years in our country, there exists a substantial mistaken understanding as the relations between “preamble” and technical features. This article will use the “riddle” and “answer” relations as an example to explain the “preamble” and technical feature relationship.


    “With a lotus worn on the head, And a colorful clothes not from tailor, It is a true hero, Once it sings all’ll open doors.” This is a riddle familiar to all children. It refers a cock that crows in the morning.


    Every line in the riddle may be seen as a limitation; the four lines together constitute a technical solution. And the four limitations can only be met in a cock. A peacock can meet most of the limitations except “Once it sings all’ll open doors,” and can therefore excluded. From this, it can be seen that the congregation of the four limitations point directly to the domestic bird of a “cock”.


  2. Relations of “Preamble” “Pureness” and Limitations


    The rationale for patent claims are the same. Since a dependent claim must “recite” a preceding independent claim, it must copy the preamble of the independent claim. Therefore the “preamble” is meaningful only to the independent claim. This article will focus only on independent claim preambles.


    1. “Pure” Preamble

    Now, let’s take a camera claim (example), to explain relations between “ preamble ” and “limitations”.


    “A camera, comprising, wherein: A body;

    An optical lens system mounted on said body;

    A shutter for use with optical lens system control to form an image

    An image medium for storing and representing said image”


    In this claim, “a camera” is the “preamble,” and the words following “wherein” are the limitations which form a camera. A camera may come in different types, but this claim seeks protection of an apparatus comprising these limitation which is this particular camera. Therefore we may conclude: the preamble is the “object” for all these limitation, and the relation between “preamble” itself and the “limitation” is the “external/internal” relations, which bounds the two together, yet making them separate in nature.


    In the above example, the camera, being the “preamble,” directly indicates the object – photographic equipment, which does not contain any descriptive “adjective,” which, being straightforward preamble, is referred to in this article as “pure preamble,” or the standard expression of “preambles.”


        2.“Non-pure” Preambles


In this article, “Non-pure” preamble refers to “object” containing, apart from straightforward preamble, other limiting contents which must be bared carefully to expose the preamble. Take the following examples:


        (1) Preamble with Recitational Relations


In the patent infringement case of XingHe Co. v. RunDe Co.,1 an independent claim is as follows: “1. A compound plastic drainage pipe reinforced with steel stripe;

2. A method for making said drainage pipe reinforced with steel stripe of claim 1,”

and “6. An apparatus for implementing said method of claim 2 for making said drainage pipe reinforced with steel stripe.”

wherein, claim 1 contains a “pure preamble,” but in claims 2 and 6, the attributive language “for making said drainage pipe reinforced with steel stripe of claim 1” and “for implementing said method of claim 2,” i.e., “attributive adjective + preamble noun,” is what is referred to in this article as “non-pure preamble.”


Are these attributive elements in “non-pure preamble” limiting by themselves? If they are, in what way they limit the entire technical solution? If not, what are they then? In claim 1, the preamble “a compound drainage pipe reinforced with steep stripe” is a product claim.


In claim 2 the preamble “method for making …,” apart from its attributive adjectives, is a method claim. Both are independent claims of different types. Further analysis reveals that claim 2 attributive elements define the “product” made under this method is “said drainage pipe reinforced with steep stripe of claim 1” Apparently, there is a recitational relationship this manufacturing method and claim 1, in other words, the method is correlative with claim 1, for if product derived from the method is different from what is recited in claim 1, there would be no such correlation. For this correlation, we may derive that it is indicative of the “single subject matter” as required by the patent law. Therefore, by the “personality” of patentability requirement, claim 2 must be independent of claim 1, but there is inevitable correlation between them, to which we must pay attention.


Rule 5.19 of PCT Examining Guide provides:2

A claim may also contain a reference to another claim even if it is not a dependent claim as defined in Rule 6.4. An example is a claim with reference to another claim of different type as in: “An apparatus for implementing said method of claim [1],” or “for making said product in claim 1.” Similarly, in the case of a plug and socket, a claim for a component part may recite another corresponding part, as in “a plug to be coupled with said socket of claim 1.” Such claims are not independent claim, for they do not contain the limitations of the recited claims, but merely indicate functional correlations with the recited claims.


          (2) Claims with “Preambles” Inconsistent with the “Limitations”


A claim “preamble” ought to represent the purpose of the invention, and only under a “preamble” so defined could a congregation of limitations constitute a technical solution for achieving such purposes. Therefore, the “preamble” must be highly consistent logically with the “limitations”. But in reality, “preambles” frequently deviate from “limitations” as in these examples: “1. Copper tin displacement of PC board method3, comprising wherein the steps of:

(a) having a PC board with a plurality of copper connecting points

(b) having a first groove mounted with a plurality of water spray pipes, and a liquid of tin chemical flowing out from said pipes, forming thereby a curtain of water with said pipes, into said first groove placing said circuit board;

(c) having a plurality of drainage pipes located underneath said first groove to drain said liquid;

(d) having a second groove for receiving said chemical liquid from said drainage pipes; and

(e) having a first pump for pumping said chemical tin liquid from said second groove to said first groove, forming a first liquid level difference in said first groove, while said plurality of drainage pipes discharging said liquid forming a liquid level on one of the sides of said first groove, creating thereby said liquid level difference to a first center liquid level from said water spray pipes, floating there from to said PC board displacing thereby said copper connecting points with tin connecting points.


The claim preamble is “Copper tin displacement i f PC board method,” which theoretically would comprise the steps of “copper tin displacement,” i.e., to realize copper tin displacement by these steps (limitations). But the claimed steps contain such limitations as “having PC board, first groove, second groove and first pump,” and “having a plurality of water spray pipes” and “a plurality of drainage pipes.” These steps are actually the manufacturing method for a “copper tin displacement” apparatus rather than “copper tin displacement” method itself. Anyone who performs the “copper tin displacement of a PC board” must first commit to manufacturing of a “copper tin displacement” apparatus; or in other words, what the claim intends to include within its protective range as a “hypothetical enemy” must be a “copper tin displacement” apparatus manufacturer who will, by using this apparatus, conduct copper tin displacement. This kind of claims where the “preambles” deviate from the “limitations” are typically ones of “inconsistencies of externals from internals” which is termed in this article as “non-pure” claims.


           (3) Claims Preambles Having “Use Environment”


What impact from “Use environment” element will have on protective range is an important question which is difficult to address. Let’s first look at the following case:

“1. An ink cartridge mounted on a frame (3) of an inkjet printing device4, for use with a first ink supply needle (6, 7) to supply ink to a printing head (5), said frame having upward protruding (14, 15) lever (11, 12), said cartridge comprising:

  • ink cartridge (41; 51), …;

  • ink supply nozzles (44; 54), …;

  • a multiplicity of electrical touch points (60), …; and

  • a suspending member (46; 56), ….”


A “pure” claim drafting would have concise and straightforward preamble, like “An ink cartridge” comprising … (specific limitations).

But this claim drafting is unique, having the limitation in preamble of “mounted on a frame (3) of an inkjet printing device” and adding after the preamble the limitation of “for use with a first ink supply needle (6, 7) to supply ink to a printing head (5), said frame having upward protruding (14, 15) lever (11, 12)”


The limitation of “mounted on a frame (3) of an inkjet printing device” is a use environment; while “for use with a first ink supply needle (6, 7) to supply ink to a printing head (5)” is a structural limitation; and then there is further limitation in the preamble of “said frame having upward protruding (14, 15) lever (11, 12).” Broadly speaking, all these limitations define the preamble, and since it seeks to protect “An ink cartridge …” it should define the structural elements; apparently, even the claim drafter does not believe that “frame” is part of the cartridge, but merely a mounting environment.

Now that both “frame” and “ink cartridge” are included in the claim, the preamble is extended to cover the “frame” and “ink cartridge,” or “an ink cartridge mounted with a frame,” which is therefore a “non-pure preamble.”


The question remains: how to determine the impact of inserting the structural element of “frame” into the preamble for protective range?


The fundamental principle for ascertaining the claim protective range in our country is “by the contents of the claim.” In patent infringement litigations, the independent claim with widest protective range is usually looked at, for which the drafting technique is defined in article 21 (1) of the Implementing Regulations under the Patent Law, as, “an invention or utility model independent claim shall conclude with a preamble and a set of limitations, drafted as follows:


(A) The preamble: describe in clear and concise terms the subject matter for invention or utility model and the necessary limitations of the invention or utility model closest to the prior art;


(B) Limitations: Using ‘wherein …’ or similar phraseology, to describe in clear and concise terms the limitations to set the invention or utility model apart from prior arts. These limitations together with the limitations of the preamble define the protective range for the invention or utility model.


It can be seen that in order to comply with the principle of “by the contents of the claims,” provisions of article 21 of the Implementing Regulations must be followed to treat the claim elements of “preamble + limitations” together to ascertain the protective range of an invention or utility model. 


Thus, anything included in the claim needs to be considered when determining the protective range. In U.S. practice, the MPEP Section 2111.02 also provides for the consequences of including “purpose” or “use” in the preamble on the protective range. According this provision: the impact of the preamble on claims must be decided case by case under the particular facts. The key is to analyze the preamble contents to see if it introduces any substantive impact.


In the Federal Circuit case of Pitney Bowes Inc. v. Hewlett-Packard Co., the court was of the opinion that the claim must be considered in its entirety. If the preamble constitutes limitation of the claim, or it gives life, meaning and vitality to the claim, then it should be considered as a substantive part of the claim. In Kropa v. Robie, the court considered the “abrasive part” is necessary for the claimed invention, in that the word “abrasive” gives “life and meaning” to the claim. Therefore, the preamble constituted a substantive limitation of the claim. The court further stated that the preamble would not be substantive limitation of the claim were it merely described the inherent nature of the product or purposes of the functions.


In sum, the American court believes that the preamble must be examined in its purpose or use environment, to see whether the claimed invention is structurally different from prior art (for process patents, it’s operational differences); if there is difference, then it constitutes limitation of the claim.


Similar to the above views in U.S. practice, the Examining Guidelines in our country also indicates clearly in Part Two, Chapter II, 3.1.1.:

“For product claims having a preamble containing use limitation, such use l imitations shall be considered in ascertaining protective range of the product claim, but its actual limitation depends on what impact it produces on the claimed product. For example, a claim with a preamble of ‘A mold for casting molten steel’ in which the use of ‘… for casting molten steel’ is limiting to the mold; for ‘A plastic mold for shaping ice cubes’ it can in no way be used ‘for casting molten steel’ since melting point is way below the mold ‘for casting molten steel’ and therefore does not fall within the claim’s protective range. If, however, the limitation of ‘for …’ has no influence on the claimed product or device, but merely is the description of the use or method of use of the product or device, then it will not play a role in determining novelty or inventiveness of the product or device. For example, in ‘A compound X for use …,’ if the ‘for use …’ has no impact on the compound X, it then plays no role in determining novelty and inventiveness of the compound.” As to the impact of claims with description on products or device’s purpose or use, the Chinese and American views are highly consistent, both holding: the preamble language should be considered in ascertaining a product claim’s protective range, and believing that it is limiting for the claim if it constitutes substantive impact for the protective range.


III. Conclusion


The relations between claim “preamble” and the limitations are the basic relations in patent regime. As general practice, the “pure preamble” should be adopted in drafting patent claims. Yet as technologies develop, and to indicate differences with prior art, there emerges the drafting technique of “non-pure preamble” which causes many problems for ascertaining protective range. This article attempts to make a preliminary study of the expressive style of “non-pure preamble” for claims, and tries to identify the impact of such “nonpure preamble” on protective range. In this article, claims with “non-pure preambles” are the choice of drafting technique, for which the drafter should have sufficient notice of its potential influence, for, anything included in the claim as “contents,” whether in the preamble, wil l potentially have substantive impact on the protective range. In this article particular distinction is made for unique effect of independent claims having “prima facie” recitational relations.


Translated by Zheng Xiaojun)



1 See, Jiangsu High People’s Court Decree (2012) SuZhiMinZhongZi No. 0021,, last visited March 14, 2014.

2 A claim may also contain a reference to another claim even if it is not a dependent claim as defined in Rule 6.4. One example of this is a claim referring to a claim of a different category (for example, “Apparatus for carrying out the process of Claim 1 ...,” or “Process for the manufacture of the product of Claim 1 ...”). Similarly, in a situation like a plug and socket example, a claim to the one part referring to the other cooperating part, for example, “plug for cooperation with the socket of Claim 1 ...,” is not a dependent claim as it does not expressly contain the limitations of the earlier claim from which it depends, rather it only has a functional relationship to that earlier claim.

3 See, invention patent No. 01139459.5 for “a copper tin displacement of PC board methods”

4 See, patent No. 200410001693.2 for more information.