US 3610153 A
Description (OCR text may contain errors)
United States Patent i'ai'ker ct ail Silicon Controlled Rectifier" Hobby Manual, page 55 General Electric Co. Copyright 1963 Primary Examiner-Benjamin A. Borchelt.
Assistant Examiner-Thomas H. Webb Attorneys-Harry M. Saragovitz, Edward J. Kelly, Herbert Berl and Harold W. Hilton ABSTRACT: An electronic delay squib or initiator which con tains the electronic delay circuit and the power supply as an integral part of the device. Starting time for the delay circuit is controlled by a switch which may be mechanical, electrical, or chemical as convenient or required. For convenience, the delay circuit, battery and switch arrangement may be made as an adapter and placed on existing electroexplosive devices. Closing of the associated switch places the power supply across a resistance-capacitance timing delay circuit which triggers a solid state electron device to place the power source across the explosive load.
 Inventors Robert E. Betts;
David R. Dreitzler; Nathan P. Williams, all of Huntsville, Ala.  Appl. No. 789,670  Filed Jan. 8, 1969  Patented Oct. 5, 1971  Assignee The United States of America as I represented by the Secretary 0! the Army  SELF-CONTAINED DELAY SQUIB 5 Claims, 4 Drawing Figs.
 US. Cl 102/70.2 A, 102/28 R  int. Cl ..F42c 11/06, F42c ll/OO, F42c 19/06  Field of Search l02/70.2, 28
 References Cited UNITED STATES PATENTS 3,225,695 12/1965 Kapp etal l02/70.2 3,088,006 4/1963 Kabik et al.... l02/70.2 X 3,094,932 6/ i963 Greenless l02/70.2 X
/ZZ l4 PATENTEUUBT 5M1 SHEET 1 OF 2 FIG. I
Robert E. Betts David R. Dreitzler Nathan P. Williams,
INVENT( )RS. @WW 5 4 Y W 4 B PATENTEU mm 5 SHEET 2 BF 2 FIG. 3
5/ M 2w I? Y R E T A B FIG..4 Robert E. Befls David R. Dreitzler Nathan P. Williams,
SELF-CONTAINED DELAY SQUIB SUMMARY OF THE INVENTION The apparatus of the present invention is a self-contained electronic delay squib. When it is desired to activate the particular system associated with the squib, a switch is closed which allows a time delay circuit to be activated by a power source. After a predetermined delay a solid state switching circuit is activated and the power supply current is allowed to flow through the load circuit for activation thereof. The delay circuit may be of a single-shot nature or may be readily adapted for repeated use.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic of a preferred embodiment of the invention.
FIG. 2 is a schematic of another embodiment of the inventron.
FIG. 3 is a diagram of a delay squib incorporating a delay circuit and power supply.
FIG. 4 is a circuit diagram of the delay circuit and power supply incorporated within an electrical connector.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, like numbers represent the same component in each figure. FIG. 1 discloses a preferred embodiment of the present invention. A silicon-controlled rectifier 10 has the cathode gate 12 thereof connected to a common point 20 between a series-connected capacitor 22 and resistor 24. The other side of capacitor 22 is connected to the cathode I4 of rectifier l and to the negative side of a power source 18. The positive side of power source 18 is connected to one side of a switch 26, the other side of switch 26 being connected to resistor 24 and to a first terminal of a firing bridge 28 of an explosive device. A second terminal of firing bridge 28 is connected to the anode 16 of rectifier 10.
Switch 26 may be of any convenient type or construction that will remain closed when activated to allow the circuit to become operative. Closing of switch 26 places battery 18 across resistor 24 and capacitor 22, building a charge across the capacitor. When the potential across capacitor 22 is sufficient to trigger the cathode gate 12 of rectifier 10, the rectifier will conduct. When rectifier l0 conducts a minimum impedance is present in the rectifier and therefore a maximum current will flow through the rectifier and the load, firing bridge 28. Current flowing through bridge 28 triggers the squib. By varying capacitor 22 or resistor 24, the circuit delay time can be controlled and preset to a selected value.
FIG. 2 discloses another embodiment of the present invention. Whereas, before, a single-throw switch was shown in the positive side of the circuit, a double-throw switch 32 is presently connected to the negative side of battery 18. In the static or inactive state the switch places a short circuit across capacitor 22. In the active state switch 32 connected negative battery to capacitor 22 and to cathode 14 of rectifier 10. Further, a zener diode 30 is connected between common point 20 and cathode gate 12 of rectifier 10, the zener diode anode being connected to gate 12.
Switch 32 allows ready discharge of residual voltage from capacitor 22 when the circuit is used for testing or other similar functions. Diode 30 may be used in either the configuration of FIG. I or FIG. 2 and allows a longer delay time before rectifier I0 is activated. When switch 32 is closed to place battery 18 across the circuit, capacitor 22 must charge sufficiently to overcome zener diode 30 before rectifier will conduct. Including diode 30 in the circuit of either figure allows a much greater time delay of the circuit with very little increase in the physical size thereof.
FIG. 3 is a diagram representative of a squib embodying the delay circuit and power source therein. A squib housing 40 includes a timing circuit and battery 42, and switch terminals 44. Force applied to a piston 46 drives the piston into contacts 44 and provides a current path therethrough to activate the circuit. Either one of the circuits of FIGS. 1 and 2 is operative here with switch 26 or 32 being replaced or embodied as contact 44 and piston 46.
FIG. 4 discloses the timing circuit, battery, and switch housed within a connector 50 that attaches to squib 52. The load, firing bridge 28, is electrically the same as has been previously described but is physically in a difierent housing. The electrical circuit between bridge 28 and the remainder of the circuit is completed when output leads or connectors 54 are mated to connectors 56. Circuit operation is as has been previously stated, however, the particular switch 60 is shown to further indicate how a variety of switching means can be utilized. Switch 60, a squib switch, is a capsule with two sets of leads 62 and 64. A triggering or firing current applied to input leads 62 causes the switch to explode and close contacts which short leads 64 together and thereby activate the circuit.
Although a particular embodiment and form of this invention has been illustrated, it is obvious to those skilled in the art that modifications may be made without departing from the scope and spirit of the foregoing disclosure. Therefore, it is understood that the invention is limited only by the claims appended hereto.
I. A self-contained electric delay squib assembly comprising: a power source; an electronic delay circuit; means for switching said delay circuit across said power source; a squib load circuit connected as an output to said delay circuit for activation thereby; said delay circuit including a series connected resistor and capacitor, a silicon controlled rectifier, and a zener diode; the cathode gate of said silicon controlled rectifier being connected through said diode to a common point between said seriesed resistor and capacitor, the
cathode of said silicon controlled rectifier being connected to the other side of said capacitor; said squib load having a firing bridgewire connected as an output to said delay circuit, a first lead of said bridgewire being connected to the anode of said silicon controlled rectifier and a second lead being connected to the other side of said resistor for activation thereof by said delay circuit.
2. A delay squib assembly as set forth in claim I wherein said-switching means includes a normally open set of leads' between a first side of said power source and said delay circuit, said normally open leads being closed by said switching means to activate the squib assembly, a second side of said power source being connected to the second lead of said bridge wire. 1
3. An electronic delay squib adapter for attachment to and firing of a squib and comprising a connector assembly for mating' with a squib and completing electrical circuits thereto; a direct-current power source; an electronic timing delay circuit; switching means for connecting said delay circuit across said power source; a pair of output leads for electrically connecting said adapter to said squib; and wherein said delay circuit includes a silicon-controlled rectifier and a series connected resistor and capacitor; said rectifier having a cathode gate connected to a common point between said resistor and capacitor and having a cathode thereof connected to the other side of said capacitor; an anode of said rectifier being connected to one of said output leads, and the other output lead being connected to the other side of said resistor.
4. An adapter as set forth in claim 3 wherein said power source is connected on one side to the cathode of said rectifier and on the other side through said switching means to the second output lead; and said connector assembly, power source, delay circuit, switching means, and output leads are contained within the same housing.
5. A squib adapter as set forth in claim 4 wherein said switching means is a squib switch having two output wires and two input wires; one of said switch output wires being connected to said power source and the other being connected to said second output lead; said switch being responsive to an input signal to close a contact between the output wires for activating the delay circuit.