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.
June 21, 1834.
Once a patent reaches its full term, the inventions claimed in that patent become public domain forever.
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
He invented the first mechanical Cotton Gin in 1797 and applied for a patent in 1798. The patent was granted in 1807.
United States Patent and Trademark 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.
Yet to be unequivocally demonstrated after 90 years of patent publications in the area, a mechanical propulsion device is presumably a combination of mechanical parts in a rotary configuration that on rotation generates net linear thrust with application of torque.
Harry Radzinsky has written: 'Making patent drawings' -- subject(s): Mechanical drawing
The mechanical reaper was invented by Cyrus McCormick, not Jo Anderson. He applied for the patent in 1834.
Cyrus Mc Cormick invented a mechanical reaper for farmers and obtained patent in 1834.