His last patent, a modification of a magnetic switch commonly found in homes, was granted on December 18, 1984, almost two years after his death.
It is the "Magnetic Switch" U.S. Patent No.
4,489,297 
Haydon's last patent was granted after his death.
Haydon died in Middlebury, Connecticut, on January 11, 1982, of an aortic dissection His last patent, a modification of a magnetic switch commonly found in homes, was granted on December 18, 1984, almost 2 years after his death.
It is the "Magnetic Switch" U.S. Patent No.
4,489,297
His last patent, a modification of a magnetic switch commonly found in homes, was granted on December 18, 1984, almost two years after his death. It is the "Magnetic Switch" U.S. Patent No. 4,489,297 
Haydon's last patent was granted after his death. Haydon died in Middlebury, Connecticut, on January 11, 1982, of an aortic dissection His last patent, a modification of a magnetic switch commonly found in homes, was granted on December 18, 1984, almost 2 years after his death. It is the "Magnetic Switch" U.S. Patent No. 4,489,297
A. W. Haydon