The present disclosure relates to an initiator assembly that is resistant to shock.
This section provides background information related to the present disclosure which is not necessarily prior art.
U.S. Pat. No. 7,571,679 discloses an energetic material initiation device with a header assembly that includes an exploding foil initiator. While this device works very well for its intended purpose, we have noted that in high-shock situations (i.e., where the device experiences high levels of shock before the device is operated) it is possible for the shock to crack the (compacted) input charge. The cracking of the input charge increases the risk that the input charge would fail to detonate.
We surmise that due to changes in elevation across the header assembly that are related to the thickness of the contacts, the thickness of the solder that is employed to secure the contacts to the exploding foil initiator, the thickness of the barrel, etc., the input charge is not supported to a maximum extent on a side adjacent the exploding foil initiator. Consequently, the void space between the header assembly and the input charge provides space for portions of the input charge to move by a sufficient amount in a high-shock situation to cause the input charge to crack.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
In one form, the present disclosure provides an initiator assembly that includes an input charge formed of a secondary explosive and a header assembly having a header body, a plurality of terminals, a plurality of seal members, an insulating spacer, a frame member, an initiator chip and a support member. The header body has an interior surface and a plurality of terminal apertures. Each of the seal members is received in an associated one of the terminal apertures and is sealingly engaged to the header body and an associated one of the terminals. The insulating spacer is abutted against the interior surface of the header body. The frame member overlies the insulating spacer and defines an interior aperture. The initiator chip has a plurality of bridge lands, a bridge and a flyer. Each of the bridge lands is electrically coupled to an associated one of the terminals. The flyer is disposed on a side of the bridge opposite the header body such that the bridge is disposed along an initiation axis between the flyer and the header body. The support member overlies a portion of the initiator chip and defines a first header surface with a central aperture formed there through. One of the initiator chip and the support member forms a barrel with a barrel aperture that is disposed in-line with the flyer and the bridge along the initiation axis. The first header surface has a flatness that is less than or equal to 0.006 inch.
In still another form, the present disclosure provides an initiator assembly that includes a header body, a frame member, a plurality of terminals, an initiator chip, a plurality of contacts, and a support member. The frame member is coupled to the header body and defines an interior aperture. The terminals are received through the header body and the frame member. The initiator chip is received in the frame member and has a plurality of lands, a conductive bridge and a flyer that is disposed over the conductive bridge. Each of the contacts is soldered to an associated one of the terminals and an associated one of the lands. The support member is formed of plastic and encapsulates the frame member, the plurality of contacts, and a portion of the initiator chip. The support member forms a barrel aperture over the flyer. The input charge is formed of a secondary explosive and is disposed in-line with the barrel aperture.
In yet another form, the teachings of the present disclosure provide an initiator assembly that includes an input charge, which is formed of a secondary explosive, and a header assembly having a header body, a plurality of terminals, a plurality of seal members, an initiator chip and a support member. The header body has an interior surface and a plurality of terminal apertures. Each of the seal members is received in an associated one of the terminal apertures and is sealingly engaged to the header body and an associated one of the terminals. The initiator chip is coupled to but electrically insulated from the header body. The initiator chip has a plurality of bridge lands, a bridge and a flyer. Each of the bridge lands is electrically coupled to an associated one of the terminals. The flyer is disposed on a side of the bridge opposite the header body such that the bridge is disposed along an initiation axis between the flyer and the header body. The support member overlies a portion of the initiator chip and defines a first header surface with a central aperture formed there through. One of the initiator chip and the support member includes a barrel that defines a barrel aperture. The barrel aperture is disposed in-line with the flyer and the bridge along the initiation axis. The first header surface has a flatness that is less than or equal to 0.006 inch.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
With reference to
With reference to
With reference to
The terminals 42 can be received in respective ones of the terminal apertures 58 and can extend outwardly from the first and second end faces 50 and 52. It will be appreciated that the terminals 42 can be arranged in a non-symmetrical manner to thereby key the header 20 in a particular orientation relative to a fireset device (not shown) to which the initiator assembly 10 is to be coupled. It will also be appreciated that a keying feature, such as a tab (not shown) or a recess (not shown), can be incorporated into a portion of the header 20 (e.g., the header body 40) to key the header 20 in a particular orientation.
The seal members 44 can be formed of a suitable material, such as glass conforming to 2304 Natural or another dielectric material, and can be received into an associated one of the terminal apertures 58. The seal members 44 can sealingly engage the header body 40 as well as an associated one of the terminals 42.
The insulating spacer 22 can be formed of a suitable dielectric material, such as polycarbonate, synthetic resin bonded paper (SRBP) or epoxy resin bonded glass fabric (ERBGF), and can have a plurality of clearance apertures 68 that are sized to receive the terminals 42 there through. The insulating spacer 22 can be received onto the second end face 52 and within an area that is defined by the size (i.e., perimeter) of the annular shoulder wall 56.
With reference to
The initiator chip 26 is configured to be fixedly coupled to but electrically insulated from the header body 40. With reference to
Each of the contacts 28 can be formed of a suitable electrically conductive material, such as KOVAR®, and can electrically couple an associated one of the terminals 42 to an associated one of the bridge lands 82 and 84. In the example provided, each of the contacts 28 is soldered to an associated one of the terminals 42 and an associated one of the bridge lands 82 and 84. While the contacts 28 and the layer of solder between the contacts 28 and the bridge lands 82 and 84 can be relatively small, their presence significantly affects the overall flatness across the side of the initiator chip 26 that faces away from the second end face 52 (
With reference to
If desired, the support member 30 can be pre-formed and assembled to the initiator chip 26, the contacts 28 and the header body 40. In such case, it may be beneficial to have a substance, such as an epoxy adhesive, that is disposed between the support member 30 and the initiator chip 26 and the contacts 28 to secure the support member 30 to the initiator chip 26 and the contacts 28 and/or to fill void spaces that might otherwise be present between an interior surface 110 of the support member 30 and surfaces of the initiator chip 26 and the contacts 28. In the present example, the support member 30 is formed via injection molding directly onto the remainder of the header assembly 12 (i.e., the portion of the header assembly 12 that excludes the support member 30) so that no void spaces are present between the support member 30 and the initiator chip 26 and the support member 30 can be cohesively bonded to the initiator chip 26, the contacts 28, the frame member 24 and the second end surface 52 of the header body 40. Configuration in this manner encapsulates the insulating spacer 22, the frame member 24, the ends of the terminals 42 that are received through the seal members 44, the initiator chip 26 and the contacts 28, which can improve the overall rigidity of the header assembly 12. Molding of the support member 30 directly onto the remainder of the header assembly 12 also permits the barrel aperture (i.e., the through-bore 100 in the example provided) to be formed with a fillet radius 120 on a side of the barrel 108 that faces away from the bridge 86. Suitable materials from which the support member 30 may be formed via molding include polycarbonate, including optically transparent polycarbonates, and liquid-crystal polymer (LCP).
With reference to
Returning to
The input charge 16 can be received in the cavity 130 and can have an axial end 150 that can be abutted directly against the first header surface 90. Optionally, as shown in
Returning to
With reference to
The input charge housing 200 is configured to retain and/or constrain the input charge 16 and can be employed to segregate the input charge 16 from the output charge 202. The input charge housing 200 can be formed of an appropriate material, such as a rigid plastic or metal material, and can define an input charge bore 210 into which the input charge 16 can be received. The input charge housing 200 has a first axial surface 212, which is disposed proximate or adjacent the support member 30, and a second axial surface 214 that is disposed opposite the first axial surface 212. In the example provided, the input charge bore 210 is a blind bore that extends only through the first axial surface 212. It will be appreciated, however, that the input charge bore 210 could be formed differently and could extend through the second axial surface 214. The input charge housing 200 can be assembled to the cover housing 134a in any desired manner. For example, the input charge housing 200 can have a housing body 216 that can be slidably received in a housing bore 218 formed in the cover housing 134a. In the example provided, the input charge housing 200 includes a flange member 220 that is disposed about and extends outwardly from the housing body 216, while the cover housing 134a defines a counterbore 222 with a shoulder 224; the flange member 220 is received into the counterbore 222 and the flange member 220 is abutted to the shoulder 224. The input charge housing 200 can be retained to the cover housing 134a in any desired manner. For example, threaded fasteners, mating external and internal threads (on the housing body 216 and cover housing 134a, respectively), one or more welds and/or an adhesive can be employed to fixedly couple the input charge housing 200 to the cover housing 134a. In the embodiment shown, however, a continuous butt weld between the flange member 220 of the input charge housing 200 and the perimeter of the counterbore 222 in the cover housing 134a is employed to fixedly couple the input charge housing 200 to the cover housing 134a, as well as to seal a portion of the volume of the housing bore 218 at a location between the output charge 202 and the header assembly 12. The input charge 16 can be consolidated into the input charge bore 210, or could be pre-formed (compressed) as one or more pellets and inserted into the input charge bore 210.
As in the above-described example, a barrier 160a can be disposed between the first header surface 90 of the support member 30 and the axial end 150 of the input charge 16. The barrier 160a can be configured to inhibit the material that forms the input charge 16 from breaking apart and falling into the barrel aperture (i.e., the through-bore 100 in the example provided) onto the flyer 88 (
If it is included, the output charge 202 can be formed of a suitable energetic material, such as an explosive material (i.e., a material that is intended to detonate) or a pyrotechnic material (i.e., a material that is intended to combust). In the example provided, the output charge 202 is formed of a secondary explosive material. The output charge 202 is received between the cover member 136 and the input charge housing 200. In the example shown, the output charge 202 abuts the second axial surface 214 of the input charge housing 200 and extends to the perimeter of the housing bore 218 in the cover housing 134a. The output charge 202 can be consolidated into the housing bore 218, or could be pre-formed (compressed) as one or more pellets and inserted into the housing bore 218.
If it is included, the cover member 136 can be retained or fixedly coupled to the cover housing 134a in a manner that is similar to that which is described above for the retention or coupling of the cover member 136 to the cover housing 134 (
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
This application is a continuation-in-part of U.S. Ser. No. 15/490,358 filed Apr. 18, 2017, the disclosure of which is incorporated by reference as if fully set forth in detail herein.
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Number | Date | Country |
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Entry |
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U.S. Appl. No. 14/501,656, filed Sep. 30, 2014 entitled: “High G-Force Resistant Initiator Assembly Having an Exploding Foil Initiator”. |
Number | Date | Country | |
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Parent | 15490358 | Apr 2017 | US |
Child | 16280069 | US |