This disclosure, in various embodiments, relates to igniter assemblies for igniting combustible compositions, such as igniter assemblies for illumination flares. Embodiments of the invention also relate to safety mechanisms and components thereof for preventing inadvertent ignition of such igniter assemblies, while allowing reliable ignition of such igniter assemblies, such as upon deployment of an associated parachute.
Among the various environments in which illumination flares are used, perhaps the most common environment for the use of flares involves the illumination of military battle grounds. In such applications, the flares are launched above ground or water areas where enemy personnel and vehicles are suspected to be present. The illumination provided by the flare facilitates visual detection of the enemy personnel and vehicles, providing more precise identification of target locations at which to aim ordnance. The illuminating effect provided by the flare is enhanced by equipping the flare with a parachute, which increases the flight time and illumination time by slowing the rate of descent for the illumination flare. Deployment of the parachute provides a force for actuating an igniter assembly housed in the flare.
Igniter assemblies for illumination flares include a slider that operates by sliding radially as a result of force from a parachute cable. When the slider slides radially, a striker arm is released to strike against an explosive composition to initiate ignition. Accordingly, there is a risk and safety concern that inadvertent sliding motion of the slider, such as resulting from accidentally dropping an illumination flare, may result in inadvertent ignition of the illumination flare. Therefore, reliable means for safely reducing inadvertent ignition and for providing reliable ignition upon parachute deployment are desired.
In some embodiments, retention clips for safety mechanisms of illumination flares include an abutment surface configured for abutment of an end of a rigid sleeve coupled to an igniter initiation cable and one or more protrusions configured to extend at least partially over a lateral side surface of the rigid sleeve when the rigid sleeve is retained by the retention clip. The one or more protrusions are configured to, upon a sufficient force on the igniter initiation cable, alter in structural integrity sufficiently to enable the rigid sleeve to move laterally such that the end of the rigid sleeve moves out of abutment with the abutment surface of the retention clip.
In additional embodiments, safety mechanisms for illumination flares include a rigid sleeve coupled to an igniter initiation cable and to a slider of the illumination flare, the rigid sleeve comprising an outer longitudinal end surface and a lateral side surface. A retention clip is coupled to an igniter cap of the illumination flare. The retention clip includes an abutment surface against which the outer longitudinal end surface of the rigid sleeve abuts in an initial position, and one or more protrusions extending at least partially over the lateral side surface of the rigid sleeve in an initial position.
In further embodiments, methods for igniting illumination flares include retaining an outer longitudinal end of a rigid sleeve under one or more protrusions of a retention clip and against an abutment surface of the retention clip. The rigid sleeve is coupled to a slider and to a parachute cable. A parachute coupled to the parachute cable is deployed to apply a force to the parachute cable. One or more protrusions of the retention clip are altered in structural integrity responsive to applied force to release the rigid sleeve from the retention clip. The slider is moved from a loaded position to a firing position by the application of the force to the parachute cable.
In some embodiments, illumination flares include a flare housing, a parachute, and an igniter assembly. The flare housing is configured for containing an illumination composition. The parachute is coupled to the flare housing using at least one parachute cable. The igniter assembly is coupled to the flare housing, and includes a slider operatively coupled to the at least one parachute cable, a rigid sleeve coupled to the at least one parachute cable, and a retention clip retaining an outer longitudinal end of the rigid sleeve. The retention clip includes an abutment surface against which the outer longitudinal end of the rigid sleeve abuts in an initial loaded position. The retention clip also includes one or more protrusions extending at least partially over a lateral side surface of the rigid sleeve.
The following description provides specific details, such as material types, geometries, and operating conditions in order to provide a thorough description of embodiments of the present disclosure. However, a person of ordinary skill in the art will understand that the embodiments of the present disclosure may be practiced without employing these specific details. Indeed, the embodiments of the present disclosure may be practiced in conjunction with conventional techniques and materials employed in the industry.
In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown, by way of illustration, specific embodiments in which the present disclosure may be practiced. These embodiments are described in sufficient detail to enable a person of ordinary skill in the art to practice the present disclosure. However, other embodiments may be utilized, and structural, material, and geometric changes may be made without departing from the scope of the disclosure. The illustrations presented herein are not meant to be actual views of any particular system, device, structure, or process, but are idealized representations that are employed to describe the embodiments of the present disclosure. The drawings presented herein are not necessarily drawn to scale.
As used herein, the term “substantially” in reference to a given parameter, property, or condition means and includes to a degree that one skilled in the art would understand that the given parameter, property, or condition is met with a small degree of variance, such as within acceptable manufacturing tolerances. For example, a parameter that is substantially met may be at least about 90% met, at least about 95% met, or even at least about 99% met.
As used herein, any relational term, such as “first,” “second,” “over,” “top,” “bottom,” “under,” “upward,” etc., is used for clarity and convenience in understanding the disclosure and accompanying drawings and does not connote or depend on any specific preference, orientation, or order, except where the context clearly indicates otherwise.
The present disclosure relates to a retention clip of an igniter assembly safety mechanism of an illumination flare. The retention clip includes one or more protrusions for laterally retaining a rigid sleeve coupled to an igniter initiation cable (e.g., a parachute cable). The retention clip also includes an abutment surface configured for abutting an outer longitudinal end of the rigid sleeve. When the outer longitudinal end of the rigid sleeve is positioned against the abutment surface and under the one or more protrusions, the one or more protrusions and the abutment surface may inhibit accidental actuation of the illumination flare when the illumination flare is dropped, for example.
Referring to
The slider 116 may be slidable between a loaded position depicted in
In the loaded position illustrated in
The slider 116 may be operatively connected to a parachute via an igniter initiation cable (e.g., a parachute cable, a cord, a lanyard) 130, which extends through a cable slot 104 of the igniter cap 112. The igniter initiation cable 130 may be attached to the slider 116, such as via a swage ball 132 or other enlarged member, which may be accommodated within a recess 134 of the slider 116 for securing the igniter initiation cable 130 to the slider 116. The recess 134 may be in communication with a slider slot 136 that is sufficiently wide to permit passage of the igniter initiation cable 130, but sufficiently narrow to obstruct passage of the swage ball 132 therethrough. The igniter initiation cable 130 may be aligned with a central longitudinal axis of the slider 116.
The safety mechanism 100 may include, by way of example, a rigid sleeve 102 coupled to (e.g., at least partially surrounding) the cable 130 as shown in
By way of example, the embodiment of the retention clip 200 shown in
The safety mechanism 100 may reduce the possibility of accidental ignition by inhibiting both axial and lateral movement of the sleeve 102 and, consequently, the slider 116, when subjected to accidental shock or impulse force, such as would be experienced by dropping the igniter assembly 106 or an illumination flare including the igniter assembly 106. As will be further explained below, the retention clip 200 may be configured to retain the sleeve 102 and slider 116 in the loaded position shown in
Referring to
With continued reference to
The one or more protrusions 202 may be configured to alter structural integrity (e.g., deform, deflect, bend, fracture, break, compress, change geometry) to release the sleeve 102 at a predetermined sufficient force, which may be greater than forces experienced by the sleeve 102 during impact upon dropping the igniter assembly 106 or an illumination flare including the igniter assembly 106 (such as from a height of up to about 40 feet (about 12 m) to meet United States military specifications), but less than or equal to forces exerted by the igniter initiation cable 130 when the parachute is deployed during intended use. By way of example and not limitation, in some embodiments the one or more protrusions 202 may be configured to release the sleeve 102 upon application of at least about 10 lbf (about 44 N), such as at least about 20 lbf (about 89 N), by the igniter initiation cable 130. Referring to
By way of example and not limitation, the retention clip 200 may be formed of a metal (e.g., aluminum, magnesium, zinc) or a polymer (e.g., polycarbonate, acrylic, polyvinyl chloride (PVC), polystyrene). The length L of each protrusion 202 may be between about 0.1 inch (2.54 mm) and about 1.0 inch (25.4 mm). The thickness T of each protrusion may be between about 0.05 inch (1.27 mm) and about 0.3 inch (7.62 mm). The extent E that each protrusion 202 extends from a horizontal diameter of the sleeve 102 over a top outer circumference of the sleeve 102 may be between about 10° and about 45°, such as about 30°. As noted above, one or more of the geometric and material characteristics of the protrusion 202 may be changed to provide a different release force. Additionally, one or more of the geometric and material characteristics of the protrusion 202 may be changed to customize the retention clip 200 for use with a larger or smaller illumination flare.
Although two protrusions 202 are shown in the drawings by way of example, the disclosure is not so limited. For example, retention clips 200 of the present disclosure may employ one protrusion 202 configured to extend over a portion of the sleeve 102, one protrusion 202 that fully extends over the sleeve 102 (e.g., to surround the sleeve 102), or more than two protrusions 202. If the retention clip 200 includes only one protrusion 202 that fully extends over (e.g., surrounds) the sleeve 102, the one protrusion 202 may be configured to break upon application of a sufficient lateral force to the sleeve 102 to enable the sleeve 102 to move laterally relative to the retention clip 200.
An igniter housing 150 (
As shown in
Referring to
Referring to
Upon deployment of the parachute 304, a weight of the remainder of the flare housing 302 and illumination composition therein and the opposing air drag of the parachute 304 may result in a tensile force in the igniter initiation cable 130. As described above, the force in the igniter initiation cable 130 may pull an outer end of the sleeve 102 in the upward direction 250 to decouple the sleeve 102 from the retention clip 200, resulting in actuation of the igniter assembly 106.
Although only a single igniter initiation cable 130 is shown schematically as coupling the parachute 304 to the flare housing 302 and igniter assembly 106, the disclosure is not so limited. For example, multiple parachute cables may couple the parachute 304 to the flare housing 302, one of which may be the igniter initiation cable 130 operatively coupled to the igniter assembly 106. In addition, the igniter assembly 106 is illustrated at an end of the flare housing 302 opposite the parachute 304. However, in some embodiments, the igniter assembly 106 may be positioned at another location along the flare housing 302, such as proximate the parachute 304.
The embodiments of the disclosure described above and illustrated in the accompanying drawing figures do not limit the scope of the invention, since these embodiments are merely examples of embodiments of the disclosure. The invention is encompassed by the appended claims and their legal equivalents. Any equivalent embodiments lie within the scope of this disclosure. Indeed, various modifications of the present disclosure, in addition to those shown and described herein, such as other combinations and modifications of the elements described, will become apparent to those of ordinary skill in the art from the description. Such embodiments, combinations, and modifications also fall within the scope of the appended claims and their legal equivalents.
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Number | Date | Country | |
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20170082408 A1 | Mar 2017 | US |