So, what to do? Well, it is possible to carry out your own search, quite effectively. There are a number of free patent searching websites. I describe a few below. The list is not exhaustive and you should do your own investigations as well.
What is important is developing a search strategy. This means that you need to think of keywords. A good strategy is to write down a sentence that describes the invention. The sentence can usually be divided into a subject, object and verb. Draw up a table with a column representing each of the subject, object and verb. Of course, you may need to have more than three columns. In each column, brainstorm for similes.
Once each column has been filled to the best of your ability, you can write your query string like this: (subject 1 OR subject 2 OR...) AND (object 1 OR object 2 OR ...) AND (verb1 OR verb2 OR...) and so on. This is very basic Boolean algebra, and will suffice for a basic search. Enter this phrase into the relevant field when you have chosen your portal. You will appreciate that fewer, larger columns will generate more hits and more, shorter columns will reduce the number of hits. You may have to tailor your columns while searching.
It is important that you spend as much time as possible on developing the search strategy. Don't jump in early, because you will find yourself backtracking as you discover more similes or phrases that might be relevant. One way of developing terminology is to carry out Internet searches for example using Google.
Feeling ambitious? Then try your hand at classification. The United States Patent and Trade Mark Office (USPTO) provides access to its classification system here: http://www.uspto.gov/patents/resources/classification/index.jsp This can be very difficult to navigate. So my suggestion is to do some searching using keywords first. When you get a hit that is close to what you're searching, then have a look at that document and make a note of its US classification. This will help you to navigate the maze that is the US classification system. The international classification system is easier to understand and can be found here: http://www.wipo.int/ipcpub/#refresh=page
Here are the websites that I think are good:
- Espace - http://worldwide.espacenet.com/ - According to this website, there are over 70 million patent documents that can be searched. Your keyword string can be entered in the "abstract" field. If you have figured out the international classification system, you can enter the classification code in the relevant field.
- Freepatentsonline - http://www.freepatentsonline.com/search.html. This is a good website provided you can figure out the syntax rules. The instructions are clear and spending time here is definitely worthwhile.
- Google Patents - http://www.google.com/patents Google has developed an effective search tool. However, you need to bear in mind that this website is very much focused on the US. It can be a good place to start, especially if you're trying to track down the correct classification.
Never forget the value of plain and simple Google searches. In fact, such a search should be a starting point. For example, Internet searching can give you ideas for terminology used in other countries. It's hardly worth doing a search for a device using Australian terminology when the same device is termed differently in the US, for example.
At the end of the day, it is always best to have a professional carry out patent searching. However, I do appreciate that every dollar counts during the early stages. There is no reason why you shouldn't give searching a go yourself. You may even end up learning something about the world us patent attorneys inhabit.
Apologies, but I must insert this disclaimer: I do not accept any responsibility if you carry out a search using these guidelines. As I've mentioned above, it is best to have a professional carry out patent searching.