Originally Posted by
verktyg
In the US the expression "Patent Pending" appears on a lot of products but does not protect an invention until the actual patent is published and/or issued.
The use of the term "patent pending" or "patent applied for" is permitted as long as a patent application has actually been filed. If these terms are used when no patent application has been filed it's considered a deceptive act.
That's because until fairly recently the US had a first to invent rather than a first to file operational philosophy. So all you needed was some proof you had an idea first even though others might have filed before you. One benefit with patent pending is you put competitors on notice. If they objected and showed they invented it first, you minimize your expenses and could just drop pursuing it.