One thing not yet mentioned. When marketing a device or gadget, one must be sure not to infringe on another existing patent. So at very least a patent search should be done when introducing a new gizmo.
You could do like magicians do when they invent tricks, video tape the trick and method (or in your case put the design and details, description, blah blah) in an envelope and mail it to yourself. That way you have a way to prove that you had that idea and its dated so there's no denying when you came up with it.
Unless you file a joint submission with a patent authority, or an Intellectual Property Office division of Consumer and Corporate Affairs, this idea won't be acceptable in Canadian courts. For more info, contact the federal government agency in your country.
You could do like magicians do when they invent tricks, video tape the trick and method (or in your case put the design and details, description, blah blah) in an envelope and mail it to yourself. That way you have a way to prove that you had that idea and its dated so there's no denying when you came up with it.
Another way if you ever have to prove your prior art is to take your artwork to a Notary Public and get it notarised. That will prove your art existed on that day. Even if someone else has the idea patented before you do, your prior art will prove you did it first. Patents go to the first inventor.
I did that with my pencil drawing AND a photocopy. Pencil drawings can suspected as having been modified after the notarisation date. Photocopies cannot be.
Patents are very slippery. Many patents are just a slight variation on a previous patent.
Patents are all about money, defense and offense. Large corporations will always get hit by lawyers trying to extract from corporation deep pockets. A large patent portfollio give corps a defense.
There are a lot of patent lawyers that do nothing but generate new patents based on a swist of existing patent. They then use them to hit up a deep pocket corporation.
The trick on a patent is to spread as wide a net as possible but not to the point of making it in danger of declared invalid.
Publishing prevents someone else from patenting an idea that was included in publication. Other then direct copyrights of paper, publishing does not prevent someone else from profiting from ideas in paper.
One of the classic stories is the one on Weed Eater that stole the patent from a single individual that patented using fishing line to cut weeds. The individual did not have the money to defend his patent and the larger corporation lawyers got it declared invalid.
If you don't defend your patent it will be invalid. This can take a lot of continued effort and expense. The best thing for an individual to do is try to quickly sell their patent to a large corporation.