You really need patience when searching for patents. It is fiddly, time consuming and, to be frank, quite boring. The same can be said for trade mark searching, company name searching and even Internet domain name searching.
Often, what looks like a “similar” invention on paper or in the headline can turn out, in the full view of things, to be something completely different. Hopefully, Google’s new patent search engine will make all our lives easier.
We live in hope!