It is impossible to patent a mere idea -- you must first reduce it to tangible form. To be eligible for a patent, your toy must be unique, useful and non-obvious. Of these three patent requirements, non-obviousness is the most difficult to meet, due to the low-tech nature of most toys -- your toy must exhibit a degree of innovation beyond the "state of the art" that would not be obvious to a skilled toy manufacturer. Toy designs are normally filed as utility patents, which expire 20 years after the original patent application filing date.
Conduct a "prior art" search. The term "prior art" refers to existing knowledge relating to the technology underlying your toy. You need to search for prior art to confirm that no pre-existing technology exists that is identical or similar to the technology used in the toy you are trying to patent. Although there are many ways to search for prior art, you may begin online by searching abstracts of patent applications using the PatentScope search engine on the website of the World Intellectual Property Organization.
Draft a detailed and comprehensive description of your toy. Your description should contain both drawings and text, and should establish that your invention is unique, useful and non-obvious. "Unique" means that nobody has ever invented it before, as evidenced by your prior art search. "Useful" means it serves a practical purpose. This purpose can include amusement -- for example, you may note that your toy "makes a pleasing 'pop' sound when opened..." Your description, taken as a whole, should be complete enough to allow a skilled technician to manufacture it without referring to outside sources.
Create patent claims. Patent claims define the conceptual boundaries of your patent -- they describe exactly which aspects of your toy are protected and which are not. If you draft them too broadly, the U.S. Patent and Trademark Office will reject your application or demand that you amend your claims. If you draft them too narrowly, someone else will be able to manufacture a nearly identical toy without infringing your patent. Patent claims are normally drafted with professional help.
Write a one-page abstract stating the nature and function of your toy. State succinctly why it is worthy of patent protection.
Make a digital copy of all of the above documentation.
Submit your patent application online using the electronic filing system, called EFS-Web, in the Electronic Business Center section of the USPTO website. You will be required to complete a cover sheet, a fee transmittal form and an application data sheet, all of which require basic information about you and your invention. You may pay online by credit or debt card. You may qualify for a lesser fee as a small entity if you have not licensed or sold rights to your invention prior to filing your patent application.
Answer queries and modification requests from the USPTO. For example, the USPTO may demand that you narrow one of your patent claims because a broad claim would render your innovation too obvious. You may respond by rewording the claim to meet the USPTO's objections, or by explaining to the examiner why a broad patent claim would not defeat your invention's claim to non-obviousness. It is normal to receive several modification requests from the USPTO.