3.2 The main methods of expansion
Besides the explained creative digging for other inventions, structured considerations are also made here. The expansion of the extent of the invention's definition can mainly be done according to the following three methods: 

3.2.1 Generalization
A generalization replaces the narrower definition, the narrower term, by the broader definition, the broader term; it replaces species by genus:
 

examples :

screwed on => affixed in a torque-proof way => affixed => arranged

Cl- => halogenide => anion

transistor => switch => signal combination

3.2.2 Leaving out features
This is the method explained above in connection with subcombinations. By leaving out features which are not essential for the invention, broader definitions are generated. 

3.3.3 Change of category - change of subject matter
Most patent applications have the largest deficiencies here. Often, the conceptual work of the patent practitioner stops at a sufficiently broad definition of the subject matter as distributed or used by his client or employer. Of course, it is not always necessary to claim all conceivable categories, in particular if this achieves no significantly broader protection, but (foreseeable) objections of the Examining Division may cause considerable additional costs. But it is also wrong on the contrary to consider uniformity only due to the possibility of additional costs and thus to limit the range of protection extremely, probably without any chance for relief. 

The following groups of categories are often possible as invention groups or at least claim groups:

a) Intermediate product - final product - application product

This is a classical situation in particular for pharmaceuticals. The intermediate product often defines a not-yet effective chemical composition, which, however, is necessary passed during the production of the drug. It will often be even worth-while to claim this intermediate product if it is done in a separate patent. Of course, the final product, i.e. the effective pharmaceutical substance, is always claimed. Purposefully, the application product, i.e. the galenically defined administration form also ought to be claimed. This application form is often the commercial product; thus, in an infringement procedure, it is the product with which claims for compensation of damages and for cease and desist are associated if a corresponding claim exists. Similar facts are true for semi-conductor products. The uncut and the unfinished processed wafer ought to be claimed. The individual chip may be claimed and finally the component molded into plastic.

b) New product - new use - production method

As a matter of cause, each method to a new product's production is also new since the product would otherwise be inherently anticipated by known methods. In the same way, every use, in particular every method of use of the new product is new.

c) New production method - new product - new use - new device

In the case of a new method, it is often ignored that a new product is made. Sometimes, this new product only differs by the by-products or the contamination. This, however, may be the corresponding economic value, e.g. if the new method leads to a directly applicable material since it is free of a certain contamination X. Doubtlessly, the product defined by the negative feature "free of X" is a further embodiment of the invention. Often, new devices are used in new methods, in particular if these are mechanical processing methods, e.g. extrusion methods or the like. The use of such products produced by a new method may be done in a new way. For example, the further processing of such a product may be done by leaving out formerly required intermediate processing or purification steps. An embodiment of the invention may already be very broad by the mentioned use of negative features.

Claiming embodiments of an invention in different categories frequently allows changing the width of the subject matter's definition. A new production method can mostly be used broader than the definition of the method product. The same considerations apply for the association of intermediate product - final product, device - method.

It is often ignored that subject matters of the same category are inventions to be claimed independently. A good example is the alreadymentioned reinforcement-arrangement patent (Enclosure A2). If a device consists of several partial devices combined in a particular way into the narrowest subject matter, i.e. the complete device, it is almost always possible to define and claim individual partial devices as an embodiment of the invention. This is a consideration known to most patent practitioners from the field of chemistry; it is practiced in the form of intermediate product/final product claims and discussed in the literature.2

However, this consideration is just as important for mechanical inventions and in the field of electrical engineering. In the case of mechanical inventions, the checking consideration for replacements may often lead to the suitable definition of further embodiments of the invention. If a certain component or group of components of an overall device is e.g. subjected to particular wear, it is often possible and required to have claims for such subject matters. Otherwise, without such claims, one is endangered of only covering the most lucrative business, often the spare-parts business, via the weak means of indirect patent infringement. A classical example is the invention of a new print head for an ink-jet printer. Here, independent claims have to be directed to the printer as well as to the print head itself.

Partial circuits of a certain functionality, in particular for realizing certain algorithms, may be claimed separately in the case of electrical inventions. The same is true for sections of technical computer programs.

Of course, the raw definition of this first shaping must always be measured on the closest prior art. The words or the combination of words are only possible for later claim wordings if they are novel over the prior art. Vice versa, in the case of independent inventions, different categories and the like, i.e. later independent claims, it is always to be examined whether the respective definitions require the same features or whether a broader wording is possible.