Ammunition and explosives – Igniting devices and systems – Electrical primer or ignitor
Reexamination Certificate
1999-06-30
2001-01-16
Jordan, Charles T. (Department: 3641)
Ammunition and explosives
Igniting devices and systems
Electrical primer or ignitor
C102S202400, C102S204000, C102S202600, C102S254000
Reexamination Certificate
active
06173650
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to a slapper/EFI(Explosive Foil Initiator) detonator, and more particularly to a slapper/EFI detonator having a safety and arming slider barrier for a barrel integrated with a MEMS (microelectromechanical system) energetic actuator.
2. Background Art
Microelectromechanical devices (also called micromechanical devices or micromachines) are small (micron scale) machines that promise to miniaturize instrumentation in the same way microelectronics have miniaturized circuits. Microelectromechanical(MEM) devices have configurations analogous to conventional macroscale machinery.
The exploding foil initiator (EFI), also known as the slapper detonator was developed by the DOE National Laboratories (Sandia, Los Alamos, Lawrence Livermore) in the mid 1970's for unconventional weapon applications. A detonator is the heart of a system to set off explosive devices such as warheads, torpedoes and other devices, such as air bag inflators. Traditionally, a blasting cap or a hot bridge wire in contact with a relatively easily detonated primary explosive material is used to set off the ultimate secondary explosive material. These devices have minimum safety, since rather low level, spurious electrical currents can activate the blasting cap or bridge wire. U.S. Pat. No. 4,592,280 to Marvin W. Shores and entitled
Filter/Shield For Electro-Explosive Devices
describes an explosive device called a squib which utilizes such a bridge wire. See also U.S. Pat. No. 5,621,183 to Todd R. Bailey entitled
Initiator For an Air Bag Inflator.
To overcome the above safety problem, the exploding bridge wire system was developed in which a large current is applied to a bridge wire, rapidly heating it and causing it to explode. In a further development, the exploding bridge wire was replaced with a slapper detonator which includes an exploding foil which forms part of a laminated printed circuit board type structure. When a large electrical current is passed through the foil, it rapidly explodes, or vaporizes, causing a flyer to be sheared from a plastic layer (disk) by a barrel positioned between the plastic layer and an explosive, and the flyer is directed through the barrel towards the explosive. When the flyer “slaps” against the explosive, the explosive is detonated. Slapper detonators are exemplified by U.S. Pat. No. 5,370,053 to Matthew R. Williams et al. entitled
Slapper Detonator
, U.S. Pat. No. 5,531,104 to James Barker entitled
Exploding Fail Initiator Using A Thermally Stable Secondary Explosive
; U.S. Statutory Invention Registration No. H1366 to Robert W. Bickes, Jr. et al. entitled
SCB Initiator
; and U.S. Pat. No. 4,862,803 to Eldon Nerheim et al. entitled
Integrated Silicon Secondary Explosive Detonator
. In order to avoid premature detonation of the explosive by the flyer U.S. Pat. No. 5,088,413 to Klaus B Huber et al. entitled
Method and Apparatus For Safe Transport Handling Arming And firing Of Performing Guns Using A Bubble Activated Detonator
contemplates utilizing a safety barrier apparatus, for use with a prior art EFI detonator, the safety barrier being disposed in the barrel of the EFI detonator and providing a barrier whereby the flyer impacts the barrier in the barrel when a safe-arm feature is needed to preclude premature detonation of the explosive.
A problem with the above mentioned safety barrier is that it must be manually inserted into the barrel to engage the safety mode and manually removed for arming. Accordingly, the detonator is subject to premature detonation at any time after the safety barrier is removed.
SUMMARY OF THE INVENTION
accordingly, it is a primary object of the present invention to provide an alternative EFI or slapper detonator which inherently includes all the advantages associated with EFI or slapper detonators, but which overcomes the disadvantages of known EFI or slapper detonators.
It is another object of the present invention to provide an EFI or slapper detonator having an integrated safety and arming system for closing or opening a barrel of the EFI or slapper detonator.
It is also an object of the present invention to provide an EFI or slapper detonator integrated with a MEMS energetic actuator to provide a safety and arming feature for closing or opening a barrel of the EFI or slapper detonator.
It is an additional object of the present invention to provide an EFI or slapper detonator integrated with a slider barrier which closes or opens a barrel of the EFI or slapper detonator to provide a safety and arming feature for the EFI or slapper detonator.
It is a further object of the present invention to provide an EFI or slapper detonator integrated with a MEMS energetic actuator for controlling a slider barrier which closes or opens a barrel of the EFI or slapper detonator to provide a safety and arming feature for the EFI or slapper detonator.
These and other objects of the invention are accomplished by designing and providing an EFI or slapper detonator, including a explodable foil (or bridge), a flyer plate and a barrel, with a movable barrier to close the barrel in a safety mode and for opening the barrel in an arming mode, wherein the movable barrier slides from a closed (safety) position to an open (armed) position under the control of a MEMS energetic actuator. The slidable barrier is maintained in the closed position by one or more locking devices of the MEMS energetic actuator until predetermined conditions are met to cause the locking device(s) to release the slidable barrier, thereby arming the EFI or slapper detonator.
REFERENCES:
patent: H1366 (1994-11-01), Bickes, Jr. et al.
patent: 4471697 (1984-09-01), McCormick et al.
patent: 4592280 (1986-06-01), Shores
patent: 4770096 (1988-09-01), Maruska et al.
patent: 4862803 (1989-09-01), Nerheim et al.
patent: 5088413 (1992-02-01), Huber et al.
patent: 5370053 (1994-12-01), Wiliams et al.
patent: 5431104 (1995-07-01), Barker
patent: 5621183 (1997-04-01), Bailey
patent: 5789697 (1998-08-01), Engelke et al.
patent: 5824910 (1998-10-01), Last et al.
“SLIGA Based Underwater Weapon Safety and Arming System” by L.Fan et al. Microsystem Technologies, vol. 4, Jul. 1998.
Birk Gregory R.
Fan Lawrence C.
Garvick Donald R.
Kuester Bruce R.
Homer Mark
Jordan Charles T.
Semunegus Lulit
The United States of America as represented by the Secretary of
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