The present invention generally relates to devices for initiating combustion, deflagration and detonation events.
Modern initiators, such as detonators, commonly employ materials including ceramics and stainless steels in their construction. These materials are typically selected to provide the initiator with a degree of robustness that permits the initiator to withstand extreme changes in temperature and humidity, as well as to resist oxidization. While modern initiator configurations are generally satisfactory for their intended purposes, they are nonetheless susceptible to improvement.
For example, many of these initiators, particularly those that employ exploding foil initiators, are relatively difficult and labor-intensive to fabricate. Consequently, they are relatively expensive and are not employed in many applications due to considerations for cost.
As another example, the ceramic and stainless steel materials that are employed in the construction of many detonator-type initiators are more dense than the explosive charge that surrounds the detonator-type initiator. Where an explosive is detonated by a single detonator-type initiator, perturbations in the wave front that result from differences between the density of the explosive charge and the densities of the components of the detonator-type initiator are generally not of significant concern. In situations where several detonator-type initiators are passively employed to detonate an explosive charge, however, it is highly desirable that the detonation wave front that passes through the detonators and the explosive charge propagate with little or no perturbations in the wave front to thereby achieve maximum efficiency. Consequently, configurations employing multiple conventionally-configured detonator-type initiators do not provide maximum efficiency as the densities of the materials that are used in their construction are significantly different than that of the secondary explosive that is typically employed in a main explosive charge so that significant perturbations in the wave front are generated as the wave front passes through the detonator-type initiator and into (or back into) the main explosive charge.
Accordingly, there remains a need in the art for an improved initiator.
In one form, the present teachings provide an initiator with a housing formed of plastic and a chip assembly for initiating at least one of a combustion event, a deflagration event and a detonation event. The chip assembly includes an electrically-actuated chip and a pair of electric leads that extend through the housing and are adapted to couple the electrically-actuated chip to a fireset circuit. The electrically-actuated chip is partially encapsulated in the housing.
In another form, the present invention provides an explosive device with an explosive charge that is formed of an energetic material and a detonator that is embedded into the explosive charge. The detonator includes a housing, which is formed of a plastic material, and an explosive pellet that is housed in the housing.
In yet another form, the present invention provides an initiator chip assembly with an electrically-actuated chip and a pair of contacts. The electrically-actuated chip is configured to initiate at least one of a combustion event, a deflagration event, and a detonation event in a material that is positioned in intimate contact with the electrically-actuated chip and includes a pair of terminals. Each of the electrical contacts includes a base portion and at least one deflectable spring arm that has a first end, which is soldered to an associated one of the terminals, and a second end that is coupled to the base portion. The spring arms resiliently couple the electrically-actuated chip to the base portions.
In a further form, the present invention provides a method of forming an initiator that includes: providing a lead frame having a pair of contacts; securing an electrically-actuated chip to the pair of contacts such that a first terminal on the electrically-actuated chip is electrically coupled to a first one of the pair of contacts and a second terminal on the electrically-actuated chip is electrically coupled to a second one of the pair of contacts, the electrically-actuated chip being configured to initiate at least one of a combustion event, a deflagration event and a detonation event; inserting the lead frame into a mold such that the electrically-actuated chip is disposed in mold cavity; and injecting a plastic into the mold to form a housing in which at least a portion of the electrically-actuated chip is encapsulated.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, wherein:
With reference to
With additional reference to
The lead frame 24 may include a frame structure 28 to which the electrical contacts 12 are coupled and extend inwardly from. Each of the electrical contacts 12 may include a base portion 30 and one or more deflectable spring arms 32. Each of the spring arms 32 may include a first, distal end 36 and a second, proximal end 38 that is coupled to an associated base portion 30. The spring arms 32 may terminate in a plane that is parallel to and spaced apart from a plane in which the base portions 30 are disposed. In the example provided, the first end 36 of each spring arm 32 is reflexed toward an associated base portion 30. The spring arms 32 may merge with one or more other spring arms 32 prior to intersecting an associated base portion 30.
In the example provided, the lead frame 24 is formed in a progressive die (not shown) such that a plurality of locating apertures 40 are pierced through the frame structure 28, the electrical contacts 12 are blanked and the spring arms 32 are formed. Although the lead frame 24 is illustrated as being a singularly formed article, those of ordinary skill in the art will appreciate from this disclosure that the lead frame 24 may be fabricated so that a plurality of the lead frames 24 may be joined to one another (e.g., in a progressive-type die that does not sever the individual lead frames 24).
Returning to
With reference to
Returning to
As the barrel 76 is defined by the tooling that is employed to fabricate the housing 16 and as the tooling may position the initiator chip 14 in a predetermined manner, we have found that securing the initiator chip 14 to the housing 16 via encapsulation and integrally forming the barrel 76 with the housing 16 permits the flyer 54 to be positioned relative to (i.e., spaced apart from) the pellet assembly 18 with improved accuracy and reliability.
For other known exploding foil initiators (EFI), the amount of energy that was supplied to the EFI to initiate its actuation was increased to compensate for the variance in the positioning of a flyer relative to a charge of energetic material. Essentially, the amount of energy that was supplied to an EFI to initiate its activation was based on a worst-case scenario wherein the flyer and the energetic material were spaced apart by a maximum permissible distance. The formation of the housing 16 an integrally-formed barrel 76 as detailed herein permits the flyer 54 to be more accurately and reliably positioned relative to the pellet assembly 18 so that a reduction of up to 75% in the tolerance that is associated with the dimension by which the flyer and the pellet assembly are spaced apart is possible. This reduction in the tolerance significantly improves the worst-case scenario, so that initiators constructed in accordance with the teachings of the present invention may be reliably activated with less electrical energy.
The pellet assembly 18 may include a structural sleeve 80, a first pellet 82 and a second pellet 84. The structural sleeve 80 may be employed to structurally support the first pellet 82 during its fabrication and/or initiation and may be formed of a suitable material, such as 6061 T6 anodized aluminum. The first pellet 82 may be pressed into the structural sleeve 80 at pressures that may exceed 50,000 psi or more. In the example provided, the initiator 10 is configured to initiate a detonation event and as such, the first pellet 82 may be formed of a fine particle size secondary explosive, such as RSI-007, which may be obtained from Reynolds Systems, Inc. of Middletown, Calif., HNS-IV (hexanitrostilbene), PETN (pentaerithrytol tetranitrate) or NONA (nonanitroterphenyl), while the second pellet 84 may be formed of a suitable energetic material that may be tailored to a specific situation in a manner that is within the capabilities of one of ordinary skill in the art.
With reference to
The second member 92 may be a material, such as 0.002 inch thick aluminum, that forms a barrier between the first and second pellets 82 and 84 to inhibit the first and second pellets 82 and 84 from chemically reacting with one another. Additionally or alternatively, the second member 92 may be employed to enhance or attenuate the shock wave that is created by the combustion, deflagration or detonation of the first pellet 82, and/or to form a barrier that combusts in response to the combustion, deflagration or detonation of the first pellet 82 and thereby ignites the second pellet 84.
Returning to
With reference to
In the example provided, the upper mold portion 122 includes a protrusion 150 that defines the barrel 76 (
With reference to
From the foregoing, those of ordinary skill in the art will appreciate from this disclosure that the electrical contacts 12 may be clamped between the upper and lower mold portions 122 and 124 while the initiator chip 14 may be drive away from the base portions 30 of the electrical contacts 12 by the positioning member 152 or toward the base portions 30 of the electrical contacts 12 by the protrusion 150. The resilient nature of the spring arms 32 permits the initiator chip 14 to move relative to the base portions 30 and thereby reduces the risk that the electrical contacts 12 will separate from the first and second contacts 60 and 62 (
Those of ordinary skill in the art will appreciate that the mold 120 and housing 16 (
With reference to
With reference to
While the initiator 10 has been described thus far as including a pellet assembly 18 that includes two pellets of energetic material, those skilled in the art will appreciate that the invention, in its broader aspects, may be constructed somewhat differently. For example, the initiator may include a pellet assembly with a single pellet of energetic material as shown in
While the invention has been described in the specification and illustrated in the drawings with reference to various embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined in the claims. Furthermore, the mixing and matching of features, elements and/or functions between various embodiments is expressly contemplated herein so that one of ordinary skill in the art would appreciate from this disclosure that features, elements and/or functions of one embodiment may be incorporated into another embodiment as appropriate, unless described otherwise, above. Moreover, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out this invention, but that the invention will include any embodiments falling within the foregoing description and the appended claims.
This application is a continuation of U.S. patent application Ser. No. 12/785,751 filed May 24, 2010, which is a division of U.S. patent application Ser. No. 12/468,957, filed May 20, 2009, issued as U.S. Pat. No. 7,748,322 on Jul. 6, 2010, which is a division of U.S. patent application Ser. No. 10/829,970 filed Apr. 22, 2004, issued as U.S. Pat. No. 7,690,303 on Apr. 6, 2010, the disclosures of which are hereby incorporated by reference as if fully set forth in detail herein.
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Number | Date | Country |
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01248546 | Oct 1989 | JP |
Number | Date | Country | |
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Parent | 12468957 | May 2009 | US |
Child | 12785751 | US | |
Parent | 10829970 | Apr 2004 | US |
Child | 12468957 | US |
Number | Date | Country | |
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Parent | 12785751 | May 2010 | US |
Child | 13078591 | US |