Internet search engine Google added another search software tool on Wednesday, launching a site capable of sifting through millions of U.S. patents.

Google Patent Search, launched as a beta version on Wednesday night, allows users to search the approximately seven million U.S. patents by parameters including date, issue date, patent number and inventor.

The search site also has a rotating series of images from selected patents —from the 1916 patent of the tennis racket to the less-heralded 2004 patent of the monkey-shaped camera bag.

The beta version looks back at inventions all the way to the 1790s but does not include patent applications, international patents or U.S. patents issued since mid-2006.

Google's site will compete with the search engine on the site of the U.S. Patent and Trademark Office, the government body that issues patents.

The site's launch of comes a day after USPTO awarded Google a patent for the design of its search results page, one of about 30 the company holds. The patent covers "the ornamental design for a graphical user interface" as shown in several screen shots.

Google has expanded its reach through a number of niche tools, from the satellite images of Google Earth to the recently purchased video sharing site YouTube.