Electrostatic discharge immune electric initiator

• US 5,099,762 A
• Filed: 12/05/1990
• Issued: 03/31/1992
• Est. Priority Date: 12/05/1990
• Status: Expired due to Fees

• Current Assignee: Special Devices Incorporated (Daicel Corporation)
• Original Assignee: Special Devices Incorporated (Daicel Corporation)
• Inventors: Drapala, Thaddeus R.
• Primary Examiner(s): Jordan, Charles T.
• Application Number:
  US07/623,286
• Time in Patent Office: 482 Days
• Field of Search: 102/202.1, 102/202.2
• US Class Current: 102/202.1
• CPC Class Codes: F42B 3/182 having shunting means F42B3/185 takes precedence; details of shunting devices H01R13/7032
• CPC Class Codes: F42B 3/188 having radio-frequency filters , e.g. containing ferrite cores or inductances F42B3/185 takes precedence

Abstract

An electro-explosive initiator which may be either a coaxial or floating case type, for example, and which is constructed to be immune from the effects of electrostatic discharges. The initiator includes a bridgewire and contact pins for carrying an electric igniting signal to the bridgewire. The initiator has a discrete capacitor connected across the contact pins to shunt out the energy resulting from an electrostatic discharge pulse, and for preventing such energy from reaching the bridgewire.

Claims

1. An electro-explosive initiator constructed to be immune from electro-static discharge pulses resulting from ambient electro-static fields encountered by the initiator, said initiator comprising:

a casing;

an explosive charge mounted within said casing;

a bridgewire mounted within said casing for igniting said charge in response to an electric current through said bridgewire;

first and second terminal pins directly connected to said bridgewire for supplying an electric current to said bridgewire for igniting said explosive charge;

first and second leads;

first and second splice members respectively connecting said leads to said first and second pins; and

a discrete capacitor having a capacity substantially in the range of 0.1 microfarad to 10.0 microfared, said capacitor having first and second lead wires respectively connected to said leads to said first and second splice members whereby substantially all of the energy of an electro-static discharge pulse resulting from an ambient electro-static field encountered by the initiator is shunted so as to prevent energy resulting from said discharge pulse from reaching the bridgewire.

2. The initiator defined in claim 1, in which said lead wires of said capacitor are resistance welded to said first and second splice members.

3. The initiator defined in claim 1, in which said capacitor capacity of the order of 0.33 microfarads.

4. The initiator defined in claim 1, in which said capacitor has a voltage rating of the order of 50 Volts.

5. The initiator defined in claim 1, and which includes a radio frequency filter interposed between said first and second terminal pins to absorb radio frequency signals and prevent spurious ignition of the initiator by such signals.