4.3 Dependent claims - subclaims
It is the subclaims' function to define fall-back positions for the examination procedure. Features from the description may also be used to later supplement the claim if they are sufficiently disclosed. Subclaims, however, are already examined for their patentability in the first office action or in the search report (if the Examining Division works correctly). Then, applicant has the possibility already to recognize after the first office action or the search report which features are considered by the Examining Division to be suitable as a limitation against the found prior art. 

However, subclaims may also subtly affect the interpretation of the independent patent claim. If, e.g. a "support is affixed" in patent claim 1 and if the dependent claim defines that the "support is affixed in a torque-proof way", it results in reverse that the meaning of the word "affixed" in the independent claim also covers attachments which allow the support to rotate.

Since subclaims are subject to fees in many countries, their number has to be balanced against the achieved benefit. Normally, subclaims only ought to be drafted if they have a certain likelihood to be accepted as patentable against the main claim. In contrast, narrower embodiments of the invention which are close to the main claim ought to be disclosed in the description but should not be worded as subclaims. A subclaim is only reasonable if it has still a certain scope of protection. Often, subclaims with practically no scope of protection are drafted, e.g. if the subclaim claims a concrete value within a range in the main claim.

It is smoothly possible in Europe to highly reduce the number of claims by multiple references. In the case of a subsequent application in the U.S., this is definitely to be changed. There, multiple references are to be avoided; they are expensive and easily lead to confusion and errors. Reversedly, it is no problem in the U.S. to get alternative claims of the same category.

Finally, it is sensible to direct at least one subclaim to the next larger unit used in an invention. For example, the invention could relate to a new electric connection for a heated rear window of a car. It may then be sensible also to direct a claim to a "rear window of a car with an electric connection according to one of the claims 1 - ...". The advantage of such a claim is in the calculation of the damages according to the license analogy. Given the fictive license of 5 %, 100 % are decisive: is it the electric connection traded at a couple of cents' price or the far more expensive rear window of a car with this connection.

Whether it is possible in the individual case to actually obtain higher compensation for damages with this subclaim is not certain. However, the position at court is better in any case if the patent comprises such a claim. Similar considerations apply for license negotiations.

4.4 Alternative claims
Alternative claims, i.e. same-category independent claims with different definitions, should only be set up relatively rarely; however, in individual cases they may be of core importance. An important example are inventions which are directed to two functional units being traded separately but tuned to each other, such as sender and receiver (e.g. for a new mobile radio network). It is a deadly sin in this case to only direct claims to one side. Often, this error cannot be corrected later on3. 

It is true that the Law states in § 34 (5) PatG that the application may only contain a single invention or a group of inventions, interconnected in that they realize a single inventive idea. However, this is a mere order regulation which has no influence on the patent's validity or scope of protection. The examination for unity is the Patent Office's task. The definition of patent claims with maximum scope of protection is the patent attorney's task. Of course, outgrowth is to be avoided. But good patent applications often have lack-of-unity objections. However, a "conceptual concision" for fear of lack of unity is absolutely to be avoided.

In the worst case, a lack-of-unity objection coerces a divisional application; should the financial framework not allow it, it may still be renounced after the claims, which were objected to as lacking unity, have been re-worded as dependent claims or been deleted entirely.

This, however, happens along after the day of application when the knowledge of the invention, of its relevant aspects and of the prior art is far more developed than at the time of drafting the patent application.

Making an alternative claim a subclaim by defining "... method according to claim 1, ..., using [feature A] instead of [feature B]" is not advisable. Already for formal reasons (clarity) and for the obvious circumvention of the unity requirements, such claims will mostly not be successful.

4.5 Examples for dangerous wordings
Words are the problem of all infringement procedures. There is almost no infringement case where the decision on an infringement does not depend on some view words, often only a single word. Therefore, one ought to avoid particular deficiencies of terms or wordings. This is true both for independent, dependent, and alternative claims. Some important individual aspects are considered in the following. 

Only aiming at a result or at a function entails the danger that the claim becomes unclear and the scope of protection far too broad. Therefore, Examiners are very critical of such "task-like" wordings, only indicating the aim but not the means to the aim4. On the other hand, if it is sufficiently clear, a functional definition may be the only possibility to achieve the appropriate range of protection for an important invention.

In many cases, applicants start with a very broad functional wording, but cave in completely after the Examiner's first clarity objection; they take up many features which are neither required for a limitation against the prior art nor for a clear technical definition of the invention. In mechanics, a middle course is often recommendable, i.e. to indicate a view less substantial structural elements together with a final functional feature, describing the interaction between those elements.

In particular the best inventors tend to describe their inventions in an industry jargon or an internal laboratory jargon. Naturally, that entails the danger that other skilled persons do not know these expressions or do not understand them in the same way. Thus, a patent application only should use expressions that generally exist in the technical language and as they are understood there.

A patent claim is a technical teaching for activity; it has to say how something is done, not why something works. The theory may be highly interesting and worthy of a prize in a publication. As a rule, a theory has no business in a patent application, in particular in the claim wording. In particular if the theory later proves to be wrong, this may have fatal consequences. As in all documents directed to a certain purpose it applies: If explanations (here the theory) have no effect in the best case, i.e. cannot further the case, they ought to be left out.

Formulas are excellent means of technical definition. Mathematical formulas as well as chemical formulas should be used whenever possible. However, in the case of mathematical formula it is to be taken into consideration whether the calculation determined by the formula or only the result is decisive. Both cases require different formulations in the claim.

Numerical restrictions, i.e. indications of a range, are often well suited for defining the invention's subject matter. However, it is to be carefully examined in any case:

• Is there a definition for the feature of which the range is claimed? This is often contravened. It is absolutely and always to be considered whether a definition (DIN norm, ASTM, detailed description) is required in order to clearly define the indicated range.
• Are the invention's examples within the range? The question appears to be trivial; however, when patent application's are reviewed, it appears that this is often violated.
• Is the indicated range sufficient to limit the subject matter of the claim against the prior art? This is a complex topic which is well evaluated differently by German courts and by the EPO. It is briefly referred to the detailed comments on this problem5.

If indications of percentages are used to determine ranges, it is to be evaluated exactly whether the sum of all percentages results in 100 %. This is often not easy in cases of three components and leads to definitions which may be incurably unclear.

Negative features are often encountered in practice. Negative features, excluding specific ranges or embodiments, have generally a very broad definition. As already mentioned, "the world without Paris" is far more than "the city of Vienna".

Terminal definitions in a feature often restrict the scope of protection extremely. It is always to be examined very carefully whether such a feature is really required in the concrete case or whether this causes enormous problems, even up to a practically missing scope of protection. As a rule, it is far better to operate with negative features purposefully (e.g. to say of a mixture that it is "free of solvents" and not "consisting of …..").

Sometimes - in particular in U.S. applications - it is tried to circumvent the restriction by a terminal definition in that one says "consisting essentially of". Generally, this is as unfavorable an expression as possible. It is enormously unclear. Instead, it should always be tried to define a highly precautionary limitation in preferred embodiments, i.e. in subclaims, by specific negative features.

EXERCISE

Draft a set of patent claims for the above-explained invention of Mr. Smart. Assume that his prior-art information is correct.