INITIATOR
An initiator including a housing adapted to be received in an igniter or rocket motor, at least one charge at a distal end of the housing, an electro-explosive device behind the charge for detonating the charge when subject to a voltage HV, and a pressure bulkhead behind the electro-explosive device. An electronic subsystem in the housing is connected to the electro-explosive device through the bulkhead and includes a lead for providing the voltage HV to the electro-explosive device to initiate it, and a switch in the lead which does not conduct if errant voltages are present on the lead to prevent initiation of the electro-explosive device until the correct voltage HV is present.
This application is a divisional application of, and claims priority to, U.S. application Ser. No. 15/352,652, entitled “INITIATOR”, which was filed on Nov. 16, 2016, which is a divisional of U.S. application Ser. No. 11/977,068, entitled “INITIATOR”, which was filed on Oct. 23, 2007, the disclosures of which are incorporated herein by reference in their entireties.
FIELD OF THE INVENTIONThis subject invention relates to an initiator.
BACKGROUND OF THE INVENTIONInitiators are devices including a charge initiated to ignite or begin the burning of a larger main charge or propellant.
Standards such as MIL-STD-1901A include a safety requirement to the effect that an initiator subject to 500 volts due to an errant voltage shall not detonate or deflagrate.
Although various devices for protection against errant voltages are well known, to date those skilled in the art have failed to provide a suitable initiator which meets the 500 volt no deflagration safety requirement. Previous attempts at engineering such a suitable initiator resulted in undue complexity and initiators which are difficult to install or incorporate into existing systems.
BRIEF SUMMARY OF THE INVENTIONIt is therefore an object of this invention to provide a new initiator.
It is a further object of this invention to provide such an initiator which meets or exceeds safety requirements or standard such as MIL-STD-1901A.
It is a further object of this invention to provide such an initiator which is fairly simple in design.
It is a further object of this invention to provide such an initiator which does not require any special electronic features such as low inductance cabling or the like.
It is a further object of this invention to provide such an initiator which is easy to install and incorporate into present systems without significant redesign.
It is a further object of this invention to provide such an initiator which is small in size.
The subject invention results from the realization that, in one preferred embodiment, a MIL-STD-1901A compliant high voltage initiator easily fits into existing rocket motors includes circuitry within the initiator housing which does not conduct if a voltage of less than 500 volts is present. This subject invention features an initiator comprising a housing adapted to be received in an igniter or rocket motor, at least one charge at a distal end of the housing, an electro-explosive device behind the charge for detonating the charge when subject to a voltage HV, and a pressure bulkhead behind the electro-explosive device. An electronic subsystem in the housing is connected to the electro-explosive device through the bulkhead and includes a lead for providing the voltage HV to the electro-explosive device to initiate it. A switch in the lead does not conduct if errant voltages are present on the lead to prevent initiation of the electro-explosive device until the correct voltage HV is present.
The initiator may include two charges in the distal end of the housing. One charge is a pyrotechnic material and the other charge is a detonating material. The pyrotechnic material may include BKNO3 and the detonating material may include HNS-IV.
The typical electro-explosive device is an exploding foil initiator. One possible switch is a spark gap. The electronic subsystem may further include a resistance in series with the spark gap for limiting current, a capacitance charged by a voltage on the lead, and a resistance in parallel with the capacitance.
An initiator in accordance with the subject invention includes a housing adapted to be received in an igniter or rocket motor, at least one charge in the distal end of the housing, an electro-explosive device behind the charge for detonating the charge when subject to a voltage HV, a pressure bulkhead behind the electro-explosive device, and an electronic subsystem in the housing connected to the electro-explosive device through the bulkhead. The preferred electronic subsystem includes a lead for providing the voltage HV to the electro-explosive device to initiate it, and means such as a spark gap device for preventing errant voltages from initiating the electro-explosive device.
One initiator in accordance with the subject invention features at least one charge, an electro-explosive device for detonating the charge when subject to a voltage HV, and an electronic subsystem connected to the electro-explosive device including a lead for providing the voltage HV to the electro-explosive device to initiate it, and a switch in the voltage lead which does not conduct if errant voltages are present on the lead to prevent initiation of the electro-explosive device until the correct voltage HV is present.
The subject invention, however, in other embodiments, need not achieve all these objectives and the claims hereof should not be limited to structures or methods capable of achieving these objectives.
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:
Aside from the preferred embodiment or embodiments disclosed below, this invention is capable of other embodiments and of being practiced or being carried out in various ways. Thus, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. If only one embodiment is described herein, the claims hereof are not to be limited to that embodiment. Moreover, the claims hereof are not to be read restrictively unless there is clear and convincing evidence manifesting a certain exclusion, restriction, or disclaimer.
Initiator 10,
Electronics subsection 36 is behind bulkhead 16 within housing section 18 and is electrically connected to exploding foil initiator 34 via leads 21a and 21b extending through pressure bulkhead 16. A glass to metal sealing material as shown at 38 may be used to seal leads 21a and 21b with respect to the metal bulkhead material. Leads 20a and 20b are electrically connected to electronic subsystem 36 though proximate housing closure disk or end wall 48.
Electronics subsystem 36 includes means such as a switch which does not conduct if errant voltages less than 500 volts are present on lead 20a. This feature renders initiator 10 compliant with MIL-STD-1901A. Typically, electronic subsystem 36 includes a circuit board or integrated circuitry for the various circuits and components of the electronics subsystem.
In one example shown in
Instead of spark gap 40, a solid state switch could be used, which conducts only when it receives a predetermined voltage level or a signal. A high voltage zener diode could also be used. Other switches and related circuitry are known to those skilled in the art.
In this way, the long felt need for a MIL-STD-1901A compliant high-voltage initiator is realized. The initiator is easily fitted into existing rocket motors, is fairly simple in design, and is easy to install.
This initiator assembly is received in igniter 116 which includes charge 118a (e.g., HNS-IV) and charge 118b (e.g., BKNO3). When the proper voltage is applied to exploding foil initiator 106, charge 108 detonates and the resulting shock wave through igniter housing wall 120 detonates charge 118a which detonates charge 118b. In one design, housing portion 102 is integrated with housing portion 116.
Although specific features of the invention are shown in some drawings and not in others, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention. The words “including”, “comprising”, “having”, and “with” as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Moreover, any embodiments disclosed in the subject application are not to be taken as the only possible embodiments.
In addition, any amendment presented during the prosecution of the patent application for this patent is not a disclaimer of any claim element presented in the application as filed: those skilled in the art cannot reasonably be expected to draft a claim that would literally encompass all possible equivalents, many equivalents will be unforeseeable at the time of the amendment and are beyond a fair interpretation of what is to be surrendered (if anything), the rationale underlying the amendment may bear no more than a tangential relation to many equivalents, and/or there are many other reasons the applicant cannot be expected to describe certain insubstantial substitutes for any claim element amended.
Other embodiments will occur to those skilled in the art and are within the following claims.
Claims
1. An initiator comprising:
- an over voltage protection circuitry housing;
- an over voltage protection circuitry configured to be received within the over voltage protection circuitry housing comprising: a first lead configured to charge a main charge capacitor above an EFI threshold voltage; a solid state switch connected to the main charge capacitor and a gate driver, the solid state switch configured to be off until driven to conduction by the gate driver; and the gate driver connected to a second lead,
- wherein the gate driver is configured to not drive the solid state switch to conduction if voltage less than a gate driver operating voltage is present on the second lead, and the charge voltage on the capacitor is at or above the predetermined switching voltage of greater than 500 volts;
- an electro-explosive device comprising a first charge and an exploding foil initiator (EFI) in electrical communication with the solid state switch and the main charge capacitor at a distal end of the over voltage protection circuitry housing, the EFI configured to initiate the first charge when subject to a voltage above the EFI threshold voltage; and
- an igniter comprising an igniter housing wall separating the electro-explosive device from an igniter charge disposed within the igniter,
- wherein the gate driver is configured to switch the solid state switch to discharge the main charge capacitor through the solid state switch and subject the EFI to a voltage above the EFI threshold voltage causing detonation of the first charge by the EFI, and a shock wave resulting from the detonation of the first charge is configured to detonate the igniter charge through the igniter housing wall.
2. The initiator of claim 1 further including a housing having threads configured to be received in the igniter or rocket motor.
3. The initiator in claim 1 in which the igniter charge includes two charges in a distal end of the initiator.
4. The initiator of claim 3 in which one charge of the two charges is the pyrotechnic material and the other charge is a detonating material.
5. The initiator of claim 4 in which the pyrotechnic material includes BKNO3 and the detonating material includes HNS-IV.
6. The initiator of claim 1 in which the solid state switch is a MOS Controlled Thyristor (MCT).
7. The initiator of claim 1, wherein:
- the electro-explosive device further comprises a pair of electrical pins; and
- the electronic subsystem further comprises a pair of sockets configured to receive the pair of electrical pins.
8. The initiator of claim 7, wherein the pair of sockets are configured to receive the pair of electrical pins through a pressure bulkhead.
Type: Application
Filed: Sep 4, 2018
Publication Date: Dec 27, 2018
Inventors: Barry Neyer (West Chester, OH), Daniel Raymond Knick (Sarasota, FL), Paul Thomas Moore (Cincinnati, OH), Robert Tomasoski (Centerville, OH)
Application Number: 16/120,553