Time delay systems, methods, and devices

A spring damper system for a pyrotechnic time delay may comprise: a piston; a firing pin; a hydraulic chamber, a portion of the piston disposed in the hydraulic chamber; and a first spring configured to compress in response to a time delay sequence being initiated, the piston configured to translate axially in the first axial direction in response to the first spring returning axially towards a neutral state, the first engagement end and the second engagement end configured to release in response to exiting the channel, and the firing pin configured to translate in the second axial direction in response to a second spring returning towards a second neutral state.

FIELD

The present disclosure relates generally to time delay systems, methods and devices and, more particularly, to an inert time delay device with a spring damper system.

BACKGROUND

Energetic time delay systems and methods may have various manufacturing issues. Additionally, energetic time delay systems may include trial and error tests during verification and validation of a design and each production lot in order to determine the correct timing. Due to the inefficient process of design and manufacture of energetic time delay systems and methods, energetic time delay devices may be relatively expensive. Since the delay is created with energetics, there may be obsolescence issues. Additionally, energetic time delays may be a life limited part, resulting in additional cost of replacing the energetic time delay over the life of an asset, such as an aircraft or the like.

SUMMARY

A spring damper system for a pyrotechnic time delay is disclosed herein. The system may comprise: a piston having a piston head, a first rod extending in a first axial direction from the piston head, and a second rod extending in a second axial direction from the piston head, the second axial direction opposite the first axial direction, a first end of the second rod including a first engagement end; a firing pin comprising a head and a third rod extending axially from the head in the first axial direction, a second end of the third rod comprising a second engagement end, the second engagement end releasably coupled to the first engagement end in a channel, the channel configured to maintain engagement between the first engagement end and the second engagement end; a hydraulic chamber, the piston head disposed in the hydraulic chamber; and a first spring configured to compress in response to a time delay sequence being initiated, the piston configured to translate axially in the first axial direction in response to the first spring returning axially towards a neutral state, the first engagement end and the second engagement end configured to release in response to exiting the channel, and the firing pin configured to translate in the second axial direction in response to a second spring returning towards a second neutral state.

In various embodiments, the system further comprises a pressure plate disposed in a first chamber, the pressure plate configured to travel axially in the first chamber in the second axial direction, compress the first spring, and couple to the first rod in response to being receiving an axial force. The piston may be configured to translate in the first axial direction in response to the first spring extending in the first axial direction. The first spring may be configured to compress in the second axial direction and the second spring is configured to compress in the first axial direction. In various embodiments, the system further comprises a release chamber, wherein the release chamber has a first diameter greater than a second diameter of the channel. The first engagement end and the second engagement end may enter the release chamber in response to exiting the channel. The hydraulic chamber may include a working fluid. The piston head may travel axially in the hydraulic chamber through the working fluid. The working fluid may travel through the piston head from a first side of the piston head to a second side of the piston head.

An inert time delay device is disclosed herein. The inert time delay device may comprise: a housing having a first axial end and a second axial end; an ignition disposed at the first axial end; a primer disposed at the second axial end; a spring damper system disposed in the housing, the spring damper system comprising: a first spring disposed in a first chamber of the housing, the first chamber extending axially in a first axial direction from the ignition towards the second axial end; a second spring disposed in a second chamber of the housing, the second chamber extending axially in a second axial direction from the primer towards the first axial end; a piston comprising a piston head disposed between the first chamber and the second chamber; and a firing pin releasably coupled to the piston, the piston configured to travel axially in the second axial direction in response to the first spring returning from a first compressed state towards a first neutral state, the firing pin configured to disengage from the piston in response to a first engagement end of the piston and a second engagement end of the firing pin exiting a channel, the firing pin configured to travel axially in the first axial direction in response to the second spring returning from a second compressed state towards a second neutral state and initiating the primer.

In various embodiments, the device further comprises a hydraulic chamber disposed between the first chamber and the second chamber. The piston head may be disposed in the hydraulic chamber. The device may further comprise a pressure plate spaced apart from the ignition. The pressure plate may be configured to couple to the piston in response to travelling axially in the first axial direction and engaging a rod of the piston. The first spring may be compressed in response to the pressure plate travelling axially in the first axial direction. The device may further comprise a release chamber, the first engagement end and the second engagement end disposed in the channel, the first engagement end and the second engagement end configured to release in response to entering the release chamber from the channel.

A method of using an inert time delay device is disclosed herein. The method may further comprise: receiving, via the inert time delay device, a pressure in a first chamber in response to an ignition being activated; compressing, via a pressure plate in the inert time delay device, a first spring in a first axial direction in response to the pressure; translating, via a piston in the inert time delay device, in a second axial direction in response to the first spring returning towards a first neutral state; translating, via engagement between the piston and a firing pin in the inert time delay device, the firing pin in the second axial direction; compressing, via a head of the firing pin in the inert time delay device, a second spring in response to translating the firing pin in the second axial direction; releasing a first engagement end of the piston from a second engagement end of the firing pin in response to the first engagement end and the second engagement end exiting a channel into a release chamber; translating the firing pin in the first axial direction in response to the second spring returning towards a second neutral state; and igniting, via the firing pin in the inert time delay device, a primer in response to the firing pin contacting the primer.

In various embodiments, a piston head of the piston travels axially through a hydraulic chamber in response to translating in the second axial direction. The method may further comprise coupling the pressure plate to a rod of the piston prior to translating the piston in the second axial direction. The release chamber may have a first diameter that is greater than a second diameter of the channel.

DETAILED DESCRIPTION

Time delay devices for use with mines or demolition charges currently consist of cord type safety fuses, electric, electronic, and mechanical clocks, and chemical acting devices utilizing the corrosive effect of an acid on wire. Chemical type devices usually consist of a glass vial containing an acid mounted adjacent a spring loaded wire restraining a firing pin, such that when the vial is broken the acid spills over the wire and after the time delay taken for the wire to corrode through under the action of the acid the firing pin is released. However, these chemical devices are extremely sensitive to temperature and for the same device the time delay may vary between several hours to many days under varying conditions. Also, there is no indication how quickly the wire will break under the corrosive action and should the glass vial be subjected to internal damage the possibility that the wire will break almost immediately can lead to serious accidents in relation to personnel handling the devices.

Disclosed herein are time delay systems and methods utilizing a spring damper system. In various embodiments, the time delay system utilized a mechanical delay facilitated by a spring damper system instead of energetics. In various embodiments, a time delay device with the time delay system disclosed herein would be more efficient to manufacture and/or cost less relative to an energetic time delay device, in accordance with various embodiments.

Referring now toFIG.1, a cross-sectional view of a portion of a pyrotechnic system10an inert time delay device100having a spring damper system110is illustrated, in accordance with various embodiments. The inert time delay device100is inert (i.e., chemically inactive), in accordance with various embodiments. In this regard, a life of the time delay system may be extended relative to typical time delay systems with pyrotechnic inputs and outputs.

In various embodiments, having the inert time delay device100is configured to couple to an input explosive transfer line (ETL)12and an output ETL14. In this regard, the inert time delay device100is configured to generate a time delay from receiving an input signal from the input ETL to outputting a signal to the output ETL14. In various embodiments, the inert time delay device100is adaptable for any pyrotechnic system configured for a predetermined time delay between an ETL being imitated and a firing device being initiated, such as demolition, fireworks, launch vehicle payload deployment systems, explosives in mining, or the like.

In various embodiments, the inert time delay device100comprises a housing120having a first end122and a second end124, a low energy (LE) ignition130, a primer140, and the spring damper system110. “Low energy ignition” or “gas generator ignition” as defined herein is a term of art referring to an ignition configured to generate a pressure front event at an output energy between 1 and 1000 Joules, or between 1 and 100 Joules, or approximately 10 Joules, in accordance with various embodiments.

In various embodiments, the LE or GG ignition130is disposed at the first end122of the housing120and the primer140is disposed at the second end124of the housing120. The second end124is disposed opposite the first end122. In various embodiments, the housing120may be cylindrical, cuboidal, or the like. The spring damper system110is disposed within the housing120and configured to generate a predetermined time delay from receiving an ignition at LE or GG ignition130at first end122and releasing a firing pin150into the primer140at second end124.

In various embodiments, the spring damper system110comprises a first spring111, a second spring112, the firing pin150, a piston160, and a hydraulic chamber170. The housing120comprises a first chamber121, a second chamber123, and the hydraulic chamber170disposed between the first chamber121and the second chamber123. The housing120may further comprise a release chamber125disposed between the hydraulic chamber170and the second chamber123.

In various embodiments, the first spring111is disposed between a pressure plate114and a first wall115. The first wall115at least partially defines the first chamber121of the housing120. The first chamber121is defined by an inner surface of the LE or GG ignition130, a radially outer wall of the housing120, and an axial wall (i.e., first wall115) of the housing. The hydraulic chamber170is disposed axially between the first wall115and a second wall116disposed distal to the first wall115

The pressure plate114is disposed proximate (i.e., spaced apart from), the LE or GG ignition130. The first spring111may be disposed in a neutral state (i.e., neither compress nor extended). In various embodiments, in response to LE or GG ignition130being ignited, the LE or GG ignition130may generate a flame and pressure between the LE or GG ignition130and the pressure plate114in the first chamber121. In various embodiments, as described further herein, the pressure generated from the LE or GG ignition130results in a force being applied on the pressure plate114towards the second end124of the housing120, which results in the first spring111compressing and the pressure plate114translating axially towards the first wall115.

In various embodiments, the piston160comprises a piston head162, a first rod164and a second rod166. The first rod164extends axially away from the piston head162toward the first end122of the housing120. The second rod166extends axially away from the piston head162toward the second end124of the housing120. In various embodiments, the piston head162is disposed in the hydraulic chamber170. In this regard, the piston head162may further comprise apertures disposed therethrough to allow fluid communication between sides from one side of the piston head162to the other side of the piston head162during operation of the inert time delay device100as described further herein. In various embodiments, the piston160further comprises an engagement end168of the second rod166disposed distal to the piston head162. In various embodiments, the first rod164extends through first wall115into the first chamber121. Similarly, the second rod166extends through the second wall116into the second chamber123.

In various embodiments, the hydraulic chamber170may be sealed from the first chamber121and the second chamber123by any method known in the art, such as an elastomeric seal, a gasket, or the like. In this regard, a working fluid172disposed in the hydraulic chamber170is configured is fluidly isolated from the first chamber121and the second chamber123during operation of the spring damper system110. The working fluid172may be any working fluid, such as water, oil, air, or any other liquid or gas, etc. In various embodiments, the working fluid172may be chosen based on a desired viscosity and/or a desired predetermined time delay. In this regard, the structure of the inert time delay device100may be maintained and only a working fluid172may be changed to change a delay time from first delay time to a second delay time in accordance with various embodiments.

In various embodiments, the second spring112is disposed in the second chamber123. The second spring112is disposed axially between a third wall117of the housing120and a head152of the firing pin150. Similar to the first spring111, the second spring112may be in a natural state (i.e., neither compressed nor extended) upon installation.

In various embodiments, the firing pin150comprises the head152disposed proximate (i.e., spaced apart from) the primer140and a rod154extending away from the head152towards the first end122of the housing. In various embodiments, the firing pin150further comprises an engagement end156disposed on an end of the rod154that is distal to the head152. The engagement end156is configured to engage the engagement end168of second rod166of the piston160.

The engagement end168of piston160and the engagement end156of the firing pin150may be disposed in a channel126disposed axially through the third wall117and extending from the release chamber125. In this regard, the channel126may be sized and configured to maintain engagement between the engagement end168of the piston160and the engagement end156of the firing pin during operation, and the release chamber125may be sized and configured to facilitate disengagement between the engagement ends156,168during operation of the spring damper system110. In this regard, the release chamber125has a first diameter that is greater than a second diameter defined by the channel126.

Referring now toFIGS.2and3, a cross-sectional view of an initial sequence of the inert time delay device100is illustrated, in accordance with various embodiments. As shown inFIG.2, a time delay sequence is initiated in response to the LE or GG ignition130receiving a pyrotechnic input supplied via input ETL12. In response to the LE or GG ignition130receiving the pyrotechnic input, the LE or GG ignition130may generate a low energy spark within the first chamber121between the pressure plate114and the LE or GG ignition130. In this regard, the pressure the LE or GG ignition130and creates an axial force on pressure plate114, causing the pressure plate to translate axially towards the first wall115and compress the first spring111. In various embodiments, the pressure plate114is configured to engage, and become coupled to, the first rod164of the piston160, as illustrated inFIG.3. For example, the pressure plate114may comprise a receptacle configured to receive and lock to an end of the first rod164. In various embodiments, the first spring111is in a compressed state upon engagement of the pressure plate114with the first rod164of the piston160. Thus, once the force of the first spring111exceeds any remaining generated from the low energy spark of the LE or GG ignition130, the first spring111translates the pressure plate114, and the piston160axially towards the first end122of the housing120as illustrated inFIG.4.

With reference now toFIG.4, in response to the piston160translating axially towards the first end122of the housing120, the piston head162travels axially through the hydraulic chamber170. In this regard, the piston160is dampened by the working fluid172in the hydraulic chamber170. As mentioned previously herein, the working fluid may be chosen based on how long a specific application is seeking to delay the pyrotechnic signal. For example, a higher viscosity working fluid may be chosen for a longer delay relative to a lower viscosity fluid. As the piston head162travels axially through the hydraulic chamber170, the working fluid may flow through the piston head162from one axial side of the piston head162to a second axial side of the piston head162.

In various embodiments, in response to the piston160translating axially towards the first end122of the housing120, the second rod166of the of the piston160pulls the rod154of the firing pin150through the channel126of the housing120. In this regard, the engagement ends156,168are pulled towards the release chamber125of the housing120. In doing so, the head152of the firing pin150begins to compress the second spring112, which begins to create stored potential energy within the second spring112.

Referring now toFIG.5, in response to the piston head162of the piston160translating from a first axial side to a second axial side of the hydraulic chamber170, the engagement ends156,168enter the release chamber125of the housing120. As mentioned previously herein, the release chamber125has a diameter that is greater than the channel126of the housing120. In this regard, in response to the engagement ends156,168entering the release chamber125, the engagement ends156,168are configured to disengage and release the firing pin150from the piston160as illustrated inFIG.6, in accordance with various embodiments.

At the point of disengagement, the second spring112is compressed within the second chamber123between the head152of the firing pin150and an axial surface of the third wall117. Due to the compression, the second spring112comprises stored energy, which is released in response to disengagement of the engagement ends156,168.

Referring now toFIG.6, the second spring112translated the firing pin150axially towards the second end124of the housing120causing the head152of the firing pin150to contact the primer140igniting a respective propellent in the primer140, which in turn ignites an output ETL14and to complete a respective time delay.

In various embodiments, various aspects of the inert time delay device100may be sized and configured based on a predetermined time delay of the respective inert time delay device. For example, a spring having a specific spring constant may be varied in first spring111or second spring112to vary a respective time delay, a viscosity of working fluid172may be chosen based on a desired time delay, or the like. Similarly, an axial travel distance of the engagement ends156,168may be varied or modified based on a desired time delay, or the like. In various embodiments, the mechanical aspects of the inert time delay device100may provide limited variations in a respective time delay compared to electronic time delay devices or other typical electronic device, in accordance with various embodiments. Similarly, due to the mechanical nature of the inert time delay device100, less testing, and/or lower cost, relative to typical time delay devices may be achieved.