In US patent practice, the terms you're using, "full patent" and "mechanical patent," don't have any meaning. The United States Patent and Trademark Office grants three types of non-provisional patents: design patents, plant patents, and utility patents. They protect different things; one doesn't "override" the other.
Once a patent reaches its full term, the inventions claimed in that patent become public domain forever.
June 21, 1834.
Yes, if you have a new and non-obvious chemical or mechanical way to improve the art, you may be entitled to a patent.
MECHANICAL
United States Patent and Trademark Office
He invented the first mechanical Cotton Gin in 1797 and applied for a patent in 1798. The patent was granted in 1807.
A provisional patent provides temporary protection for an invention, while a non-provisional patent offers full patent protection and must be examined by the patent office.
Newborns with patent ductus arteriosis, a handicap affecting the pulmonary artery, are more likely to suffer pulmonary hemorrhage from mechanical ventilation.
John Gorrie patented an ice machine in 1851.
The mechanical reaper was invented by Cyrus McCormick, not Jo Anderson. He applied for the patent in 1834.
Harry Radzinsky has written: 'Making patent drawings' -- subject(s): Mechanical drawing
Contact a patent practitioner (patent agent or patent attorney) for assistance. The United States Patent and Trademark Office has lists and addresses of patent practitioners in every state. A patent practitioner will assist you in making the necessary full disclosure of your invention, including any diagrams, and making claims to your invention. They will also help you deal with the inevitable rejections or objections to your application, perhaps submitting amendments or other documentation.