Shaped bridge slapper

Details Shaped bridge slapper Shaped bridge slapper

1999-03-19

2001-05-22

Carone, Michael J. (Department: 3641)

Ammunition and explosives

Igniting devices and systems

Electrical primer or ignitor

C102S202500, C102S200000, C102S202700

Reexamination Certificate

active

06234081

ABSTRACT:

FIELD OF INVENTION
This invention relates generally to devices for setting off an explosive charge and more particularly to a slapper type detonator with a shaped bridge member.
BACKGROUND OF INVENTION
Slapper type detonators in general cause a “flying plate” to be propelled at a high velocity against a secondary explosive medium creating a shock wave which results in the detonation of the secondary explosive. In a typical design, there are two wide area conductive lands separated by a narrow rectangular bridge member. The lands are connected to a capacitor through a high voltage switch. When the switch closes, the capacitor provides current across the lands which vaporizes the bridge member turning it into a plasma. This plasma accelerates a portion of the dielectric material covering the bridge member to a high velocity, causing it to slap into an explosive. The resulting shock wave causes detonation of the explosive.
Conventional slappers have a rectangular bridge which results in rectangular flying plates, the center of which leads the edges in flight. It has been discovered by the inventor of the subject invention, however, that this rectangular shape results in adverse edge effects which render the detonator inefficient.
SUMMARY OF INVENTION
It is therefore an object of this invention to provide a specially shaped bridge slapper which is more efficient than prior art slapper detonator designs with rectangular bridge members.
It is a further object of this invention to provide such a shaped bridge slapper which produces a larger shock wave than prior art designs.
It is a further object of this invention to provide such a shaped bridge slapper which requires less energy than conventional designs to provide the same shock.
It is a further object of this invention to provide such a shaped bridge slapper which can be made smaller than conventional designs.
This invention results from the realization that slapper type explosive detonator can be made more efficient and produce a larger shock wave to detonate an explosive by modifying the bridge member of the slapper to produce a curved shaped (e.g. circular) flying plate instead of the rectangular flying plate of conventional designs.
This invention features a shaped bridge slapper comprising a substrate, a pair of spaced conductive lands on the substrate, a bridge member typically extending between the spaced conductive lands, the bridge member having a curved shape and a cavity therein, and a flyer layer extending over the bridge member.
The curved bridge member is preferably circular in shape. The cavity may extend through the bridge member or may instead be an area of different material thickness. The cavity may also be filled with a material different than the material of the remainder of the bridge member.
The substrate may be ceramic and the lands and the bridge member may be made of copper. The flyer layer is typically made of a dielectric material such as polyimide.
In another design, the substrate is a face plate and the flyer layer is an epitaxial layer grown on a silicon substrate which is back etched in a zone beneath the bridge member. In another design, the slapper is an exploding foil initiator and the bridge member and the lands are foil. In this embodiment, the flyer layer is a layer of Kapton.
More broadly, this invention features a shaped bridge slapper comprising a substrate, a pair of spaced conductive lands on the substrate, a bridge member between the spaced conductive lands, the bridge member having a curved shape, and a flyer layer extending over the bridge member. Therefore, in this design there is no cavity of any kind in the bridge member. Alternatively, the shaped bridge slapper comprises a substrate, a pair of spaced conductive lands on the substrate, a bridge member between the spaced conductive lands, the bridge member having an outer conductive area and an inner area of reduced or different thickness and/or different material; and a flyer layer extending over the bridge member. Therefore, in this embodiment the bridge member may even have a conventional rectangular shape but includes a cavity therein, and/or a material such as “Kapton” or another dielectric filling the cavity. In the preferred embodiment, however, the bridge member is both circular in shape and includes a cavity therein.
DISCLOSURE OF PREFERRED EMBODIMENT
Other objects, features and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which:
FIG. 1
is a perspective view of a prior art chip slapper detonator;
FIG. 2
is a perspective view of the shaped bridge slapper in accordance with the subject invention;
FIG. 3
is a cross-sectional view of the chip slapper of the subject invention taken along the line
3
—
3
in
FIG. 2
;
FIG. 4
is a cross-sectional view of another embodiment of the chip slapper of the subject invention;
FIG. 5
is a cross-sectional view of another embodiment of the shaped bridge slapper of the subject invention; and
FIG. 6
is a perspective view of another embodiment of the shaped bridge slapper of the subject invention.


REFERENCES:
patent: 4471696 (1984-09-01), McCormick et al.
patent: 4852493 (1989-08-01), Boberg et al.
patent: 4862803 (1989-09-01), Nerheim et al.
patent: 5370054 (1994-12-01), Reams et al.
patent: 5789697 (1998-08-01), Engelke et al.
patent: 5969286 (1999-10-01), Ward et al.

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