As it turns out, there are as many origin stories for barbecue as there are spellings of the word on neon signs. These explanations range from a linguistic attempt to connect barbecue to boucan (also French) to a tall tale tracing barbecue to a Texas rancher who happened to brand the initials B.Q. on his livestock.
Patent protection usually ends when the patent expires. Here are the expiration dates: For all utility patents filed before June 8, 1995, the patent term is 20 years from date of filing, or 17 years from date of issuance, whichever period is longer.
Alternately, the provisional patent application establishes the filing date but does not start the USPTO review process. The provisional patent application provides a measure of protection for 12 months from the filing date and expires unless you file a utility patent application before the 12 months are up.