Searching for U.S. Patents on the Internet

Step 3: U.S. Patent Classification Definitions.  

The U.S. Patent Classification Definitions contain working definitions for all subclasses in the U.S. patent classification system. They should be used to further clarify exactly what is included and what is not included in each subclass. Go the Patent Classification Home page to access the definitions.

Continuing from step 2, we have identified that class 428 and subclass 299.7 may be relevant to our search. Click on the subclass number while in the classification schedule to go the classification definitions. It is important to look at the definitions because they provide a longer description of the technology in the subclass and also see references to other classes or subclasses are often provided. It also describes which subclass this class is indented under in the outline. You should consult this superior or major class as well. 

Manual of Classification listing for Class 428: Classification Definitions:

299.4	Glass fiber:
	This subclass is indented under subclass 298.1.  Subject matter wherein the embedded fibers are glass fibers.

299.7	Polymeric fiber:
	This subclass is indented under subclass 298.1.  Subject matter wherein the embedded fibers are polymeric fibers.

300.1	Fiber is precoated:
	This subclass is indented under subclass 297.4.  Subject matter wherein the fibers are coated with a material prior to being incorporated in the polymeric matrix or being affixed to a surface of the polymeric matrix.

You should also scan to the top of the class definitions for class 428 and read the information provided there. The information in the boxes below is copied from the Classification Definitions for Class 428.

Classification Definition for Class 428:

SECTION I - CLASS DEFINITION

This class accommodates certain products of manufacture which are not provided for in classes devoted primarily to manufacturing methods and apparatus. The bulk of the documents are directed to stock material composites, that is, materials having two or more distinct components which are more ordered than a mere random mixture of ingredients.

Certain finished articles, generally of an ornamental or readily disposable nature, are placed herein when this class specifically provides for them. Unfinished articles, e.g., blanks requiring further significant shaping to be suitable for ultimate use, and stock materials from which an indefinite number of usable portions may be cut, are placed herein unless specifically provided for elsewhere. The determination whether a product etc.

This introduction to this class provides valuable information and see references on how the class is organized. Sometimes, the definitions will lead to other related classes and subclasses which might be useful. 

One point about the numbering of subclasses, they will not always proceed in numerical order. As new technologies are added the the Classification Schedule, new numbers are inserted at the appropriate point in the class but the class is not renumbered. For example below subclass 687 is followed by subclass 2.

Manual of Classification listing for Class 428. Classification Schedule:

684

..... Containing 0.01-1.7% carbon (i.e., steel)

685

...... Containing more than 10% nonferrous elements (e.g., high alloy, stainless)

686

.. Adjacent functionally defined components

687

. Surface feature (e.g., rough, mirror)

2

COMPACTED TRASH OR REFUSE BUNDLE

32

ARTICLE HAVING ORNAMENTAL WOUND OR WOVEN STRANDS

33

PLURAL PARTS WITH EDGES OR TEMPORARY JOINING MEANS EACH COMPLEMENTARY TO OTHER

Use the EDIT - FIND command to locate subclass numbers within a class. 

Click on the to go to a list of patents for interesting subclasses. Review the titles and review the full patent for those of interest. If the list is not interesting, go back to the classification definitions and choose a different subclass or follow a see reference to a different class. 

Remember that the advantage of doing a classification search is that you are able to retrieve patents issued prior to 1976. This is still very important for certain technologies. The only problem is that only the patent number is displayed. You can not eliminate patents by reviewing that title and making a decision with this information. You need to access the TIFF image for each patent prior to 1976.

If there are many subclasses of interest in a particular class and they fall within the same number range, it may be advantageous to do a search on a group of classes and link this with a company or keywords. The classification subclass numbers can be truncated when searching to allow searching over a group of subclasses. For example in our current search of class 428, we may decide that there are relevant subclasses over the range 290 - 299. The Quick Search would be structured as:

Quick Search Screen:  USPTO Patent Full-Text and Image Database: