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US4395950A Expired / Lapsed US ⏱️ 0.0 years remaining

Electronic delay blasting circuit

Assignee: Orica Explosives Technology Pty Ltd
•
Filing: 1982-02-08
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Granted: 1983-08-02
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Expires: 2002-02-08
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Abstract

Abstract An electronic delay blasting cap (10) receives an input signal over leg wires (12, 14). The input signal is passed through a rectifier (16) to produce a D.C. signal on output lines (26, 28). The D.C. signal charges a storage capacitor (32). When the input signal is removed or the wires (12, 14) are opened or shorted, the charge storage capacitor (32) discharges through a resistor (36) to produce a voltage which charges a timing capacitor (38). When the voltage on capacitor (38) reaches the threshold voltage of a zener diode (48) the diode is rendered conductive which in turn activates an SCR (46). A resistive ignition element (44) is connected in series with the SCR (46) and the charge storage capacitor (32) and is ignited when the SCR (46) is turned on. The charge stored in capacitor (32) causes ignition of the ignition element (44).

Inventors

  • 👤 Gerald L. Oswald

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-30 09:37
CPC Classifications
F; F42; F42C; F42C11/00; F42C11/06

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 90 words
A method for firing a resistive ignition element following a delay period, comprising: full-wave rectifying an input signal to produce a D.C. signal, storing an electrical charge produced by said D.C. signal, generating a timing signal having a changing voltage after an amplitude transition of said input signal, detecting when said timing signal is equal to a reference voltage, transferring at least a part of said stored electrical charge to said resistive ignition element for ignition thereof when said timing signal is detected to be equal to said reference voltage.
Claim 2
Independent Claim 90 words
A method for firing a resistive ignition element following a delay period, comprising: full-wave rectifying an input signal to produce a D.C. signal, storing an electrical charge produced by said D.C. signal, generating a timing signal having a changing voltage after an amplitude transition of said input signal, detecting when said timing signal is equal to a reference voltage, transferring at least a part of said stored electrical charge to said resistive ignition element for ignition thereof when said timing signal is detected to be equal to said reference voltage.
Claim 3
Dependent Claim 23 words
The method recited in claim 1 wherein the step of full-wave rectifying comprises passing said input signal through a four diode bridge rectifier.
Claim 4
Dependent Claim 22 words
The method recited in claim 1 wherein the step of storing an electrical charge comprises charging a capacitor with said D.C. signal.
Claim 5
Dependent Claim 25 words
The method recited in claim 1 wherein the step of generating a timing signal comprises charging a capacitor with current received from said electrical charge.
Claim 6
Dependent Claim 22 words
The method recited in claim 1 wherein the step of generating a timing signal comprises charging a capacitor with said D.C. signal.
Claim 7
Dependent Claim 20 words
The method recited in claim 1 wherein the step of detecting comprises applying said timing signal to a zener diode.
Claim 8
Dependent Claim 31 words
The method recited in claim 1 wherein the step of transferring comprises firing a silicon controlled rectifier which is connected in series with said electrical charge and said resistive ignition element.

References Cited (Backward Citations)

US3306208A Cited
US3343493A Cited
US3424924A Cited
US3618519A Cited
US3610153A Cited
US3640224A Cited
US4145970A Cited
US4296688A Cited
US4227461A Cited
US4311096A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1986-08-01 1987-01-31 1987-08-02 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1990-08-01 1991-01-31 1991-08-02 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1994-08-01 1995-01-31 1995-08-02 $7700.00 Window Closed / Lapsed

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