Patents are a great source of information when reverse-engineering commercial products. In particular, review a patent's abstract and summary and annotated drawings to get an idea of the functional and design features for a particular invention.
Google Patents includes patents from the United States Patent and Trademark Office (USPTO), the European Patent Office (EPO), and the World Intellectual Property Organization (WIPO).
More options for finding patents:
"...patent applications usually contain the first disclosure of new technologies and processes and serve to link theory with practice, providing ‘real world’ examples of the application of scientific research. Increasingly, scientific discoveries are reported first in the patent literature, rather than in academic journals." (MacMillan, 2006)