Electric safety squib
First Claim
1. An electric squib comprisinga pyrotechnic charge,electrical means for igniting said pyrotechnic charge, said electrical means having a pair of terminals that normally are insulated from ground potential, andshield means for shielding said pyrotechnic charge from electrostatic energy tending to be induced in said terminals comprising electrically and thermally conductive walls surrounding said pyrotechnic charge in close physical and thermal contact therewith, one terminal of said electrical means being connected to and the other terminal thereof being insulated from said walls whereby electrostatic energy developed on said electric means is conducted around and away from said pyrotechnic charge by said walls, said shield means further including spark gap defining means between said walls and ground potential whereby electrostatic energy on said walls above a threshold value is discharged to ground by arcing.
1 Assignment
0 Petitions
Accused Products
Abstract
An electric safety squib having a grounded outer case and a pair of normally ungrounded terminals includes a closed thermally and electrically conductive container filled with pyrotechnic material. An electrical resistance wire is embedded in the pyrotechnic material for controlled ignition thereof. A separate conductor extends from each of the terminals to an associated end of the resistance wire through a resistive header and a chamber holding ferrite beads whereby energy of radio-frequency and electrostatic origin extraneously induced in the terminals and conductors is dissipated into the bulk of the conductors, the resistive header and ferrite beads. The arrangement features the disposition of the ferrite beads in good heat transfer relation with the chamber walls whereby heat is carried away from the ferrite beads to limit any rise in temperature thereof, and further features the connection of the junction of one of the conductors and the resistance wire directly to the container wall, and the spacing of the container wall with respect to the outer case to provide a measured spark gap therebetween whereby radio-frequency and electrostatic energy above a threshold value that may reach the resistance wire is conducted by the walls of the container around and away from the pyrotechnic material and is discharged through the spark gap, thereby preventing such energy from passing through the pyrotechnic charge and developing enough concentrated heat to ignite it.
73 Citations
36 Claims
-
1. An electric squib comprising
a pyrotechnic charge, electrical means for igniting said pyrotechnic charge, said electrical means having a pair of terminals that normally are insulated from ground potential, and shield means for shielding said pyrotechnic charge from electrostatic energy tending to be induced in said terminals comprising electrically and thermally conductive walls surrounding said pyrotechnic charge in close physical and thermal contact therewith, one terminal of said electrical means being connected to and the other terminal thereof being insulated from said walls whereby electrostatic energy developed on said electric means is conducted around and away from said pyrotechnic charge by said walls, said shield means further including spark gap defining means between said walls and ground potential whereby electrostatic energy on said walls above a threshold value is discharged to ground by arcing.
-
24. An electric squib for igniting an automobile air bag inflator, comprising:
-
an electrically conductive, tubular, outer housing; a dielectric sleeve that fits inside the housing; a tubular electrical conductor that fits inside the sleeve and is spaced thereby from the housing a discrete distance calculated to provide spark gaps for extraneous electrical energy of given ranges of voltages and frequencies; an electrically conductive rod centrally positioned in the housing; means for retaining the sleeve and tubular conductor in the housing; a first electrically conductive partition, that fits tightly in the tubular conductor and through which the rod extends, forming a first chamber in one end portion of the tube; a pyrotechnic material in the first chamber; means for insulating the rod from the first partition; a resistance wire attached at one end to the rod in the first chamber and at its other end to the first partition, and passing through the pyrotechnic material; a second partition that fits tightly in the tubular conductor, forming a second chamber between the first and second partitions and a connector receptacle on the other side of the second partition; and at least one ferrite bead in the second chamber, having a central hole through which the rod conductor passes. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32)
-
-
33. In an electric squib comprising,
a pyrotechnic charge, electrical means for igniting said pyrotechnic charge, said electrical means having a pair of terminals, and conventional means for attenuating radio-frequency signals and electrostatic energy that tend to be induced extraneously in said terminals, the improvement comprising providing electrically and thermally conductive walls in close physical and thermal surrounding relation with respect to said pyrotechnic charge, one of said terminals being electrically connected to said walls and the other insulated therefrom whereby electrostatic energy is conducted around and away from said pyrotechnic charge by said walls, and providing a spark gap between said walls and ground potential whereby electrostatic energy above a threshold value will be discharged from said walls to ground by arcing.
-
34. An electric squib comprising,
a pyrotechnic charge, and an electrically conductive grounded housing containing said pyrotechnic charge, electrical means for igniting said pyrotechnic charge, said electrical means having a pair of terminals that normally are insulated from ground potential, and shield means including ferrite bead means associated with said terminals for attenuating radio frequency signals that tend to be induced therein, said ferrite bead means being disposed in good heat transfer relation with said housing, said shield means further including means for shielding said pyrotechnic charge from electrostatic energy tending to be induced in said terminals comprising thermally and electrically conductive walls surrounding said pyrotechnic charge in good heat transfer relation therewith, one terminal of said electrical means being connected to and the other terminal thereof being insulated from said walls whereby electrostatic energy developed on said electric means is conducted around and away from said pyrotechnic charge by said walls, said shield means further including spark gap defining means between said walls and said grounded housing whereby electrostatic energy on said walls above a threshold value is discharged to ground by arcing.
Specification