A free patent search can be done online. It provides a wealth of information and is one of the first tools we use as inventors.
The purpose of a patent search is to collect information relevant to your invention.
You're looking for patents that are similar to your invention and collecting information that may effect the success of your idea.
Patents that are similar to your invention are known as "prior art". A patent examiner reviews prior art in determining whether you should get a patent.
You're trying to determine if your product is patentable or alternatively if any of the claims you will make will infringe a patent.
It's therefore a good idea to have a clear description of your invention when conducting a search.
Inventors often review patents to get ideas and information for developing their inventions.
It can provide a lot of useful information. There are drawings and descriptions of inventions, names of inventors, assignments and lawyers.
However, your own searches should not be a substitute for a professional search done by a competent patent attorney or agent.
There is never any guarantee that a patent search will conclusively guarantee your invention is original. There are millions of patents, and endless amounts of published materials.
To say your idea has never been publicly disclosed or patented before is virtually impossible.
The best that can be said is that the chances of finding something like your invention patented or publicly disclosed is minimal.
Such a statement has greater certainty if it's made by a patent lawyer/agent rather than an inventor.
Free Patents Online
You can search patents free online.
There are patent search engines at the US Patent Office, the European Patent Office, and WIPO (World Intellectual Property Organization) among others.
You can search the us patent office using Google. Google hosts the entire collection of patents filed with the United States Patent and Trademark Office (USPTO) - approximately 7 million patents.
Google does not yet cover International patents or U.S. patents issued over the last few months.