Mills bomb incorporated into the Mills Bomb. The Mills bomb was adopted by the British Army as its standard hand grenade in 1915, and designated the No. 5. The Mills bomb underwent numerous modifications. The No. 23 was a variant of the No. 5 with a rodded base plug which allowed it to be fired from a rifle. This concept evolved further with the No. 36, a variant with a detachable base plate to allow use with a rifle discharger cup. The final variation of the Mills bomb, the No. 36M, was specially designed and waterproofed with shellac for use initially in
Term of patent in the United States patents in the U.S., since the patent term now depends on the priority date, not the issue date. Design patents have a shorter term than utility patents. Design patents filed on or after May 13, 2015 have a term of 15 years from issuance. Design patents filed prior to May 13, 2015 have a term of 14 years from issuance. The original patent term under the 1790 Patent Act was decided individually for each patent, but "not exceeding fourteen years". The 1836 Patent Act (5 Stat. 117, 119, 5) provided (in addition to the fourteen-year term) an extension "for the