Are there free patent databases?

Yes! For example:

Depatis	—	German patent information system
Espacenet	—	Das europäische Netz von Patentdatenbanken
WIPO	—	World Intellectual Property Organization
USPTO	—	United States Patent and Trademark Office
Scopus	—	Database of abstracts and citations
Scirus	—	Academic database

The databases provide the following functions:

Function	DPMA	Espacenet	WIPO

Print search results	P	P
View bibliographic data	P	P	P
View patent family	P	P
Download the orginal document	P	P	P
Download the test report			P
Full text search in the original document	•	P	•
Claims separately listed and easily accessible		P	P
Drawings easily accessible	P	P
Cited literature identified in the search separately listed and easily accessible	P
Cited documents separately listed and easily accessible.		P
Citing documents separately listed and easily accessible.		P

Key:

P Function available

• Function partly available