Picatinny employees create grenade fuze and detonator with flying disc

Vincent Gonsalves, a technical expert from the U.S. Army Armament Research, Development and Engineering Center, was one of four inventors recently awarded a patent.

PICATINNY ARSENAL, N.J. — A major concern in the field of fuzing and detonators is the ability to meet the Insensitive Munitions (IM) compliance requirements. Insensitive munitions are designed to replace munitions that can easily be detonated by unplanned stimuli, including heat and impacts.

IM improvements are mandated by law in the United States to avoid accidents and the subsequent loss of human life, the cost of repairing and replacing material, and the toll taken on operational readiness and capability.

“Historically, the grenade fuze has been the root cause of all IM test failures for lethal grenades,” said Vincent Gonsalves, Technical Expert, Grenades and Demolitions Division, U.S. Army Armament Research, Development and Engineering Center.

Gonsalves was one of four recipients named on a recent patent for a grenade fuze with flying disc. The team consisted of William Andrews and Carl Campagnuolo of SOCOM, and James Varosh of Teledyne RISI. The official patent number is 9255777.
A photograph of the awarded patent, a grenade fuze and detonator with flying disc.


A need existed for fuzes and detonators that were less sensitive to impacts and heat than known fuzes and detonators, thus research commenced on a solution.

“The team was inspired to develop a low cost, reliable alternative to the current design and provide the Soldier with an IM compliant system. The elimination of primary explosives and replacement with secondary explosives has the additional benefit of lead removal,” Gonsalves said.

“Using the hardware and delay of the M228 fuze, the deflagration to detonation design utilizes various densities of PBXN-5 powder and pellets to accelerate a flying plate that detonates the booster,” Gonsalves said.

“The booster detonation then initiates the main fill of the grenade. Fuze design testing is on-going, followed by system testing and eventual IM system testing.”

According to Gonsalves some of the lessons learned, “include changing only one variable at a time while in the research and development phase.

Changing multiple variables during testing may be tempting and could save time and money, but there is no benefit when you have the inevitable failure and have to back track to the root cause,” he said.

The grenade fuze and detonator with flying disc patent was filed in May 2014 and approved in February 2016.

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The U.S. Army Armament Research, Development and Engineering Center is part of the U.S. Army Research, Development and Engineering Command, which has the mission to ensure decisive overmatch for unified land operations to empower the Army, the joint warfighter and our nation. RDECOM is a major subordinate command of the U.S. Army Materiel Command.