Patent Publication Number: US-11662191-B2

Title: Time delay systems, methods, and devices

Description:
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. 
     The forgoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated herein otherwise. These features and elements as well as the operation of the disclosed embodiments will become more apparent in light of the following description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present disclosure, however, may best be obtained by referring to the following detailed description and claims in connection with the following drawings. While the drawings illustrate various embodiments employing the principles described herein, the drawings do not limit the scope of the claims. 
         FIG.  1    illustrates a cross-sectional view of an inert time delay device with a spring damper system, in accordance with various embodiments; 
         FIG.  2    illustrates a cross-sectional view of an inert time delay device with a spring damper system during use, in accordance with various embodiments; 
         FIG.  3    illustrates a cross-sectional view of an inert time delay device with a spring damper system during use, in accordance with various embodiments; 
         FIG.  4    illustrates a cross-sectional view of an inert time delay device with a spring damper system during use, in accordance with various embodiments; 
         FIG.  5    illustrates a cross-sectional view of an inert time delay device with a spring damper system during use, in accordance with various embodiments; and 
         FIG.  6    illustrates a cross-sectional view of an inert time delay device with a spring damper system during use, in accordance with various embodiments; 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description of various embodiments herein makes reference to the accompanying drawings, which show various embodiments by way of illustration. While these various embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that changes may be made without departing from the scope of the disclosure. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected, or the like may include permanent, removable, temporary, partial, full or any other possible attachment option. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact. It should also be understood that unless specifically stated otherwise, references to “a,” “an” or “the” may include one or more than one and that reference to an item in the singular may also include the item in the plural. Further, all ranges may include upper and lower values and all ranges and ratio limits disclosed herein may be combined. 
     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 to  FIG.  1   , a cross-sectional view of a portion of a pyrotechnic system  10  an inert time delay device  100  having a spring damper system  110  is illustrated, in accordance with various embodiments. The inert time delay device  100  is 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 device  100  is configured to couple to an input explosive transfer line (ETL)  12  and an output ETL  14 . In this regard, the inert time delay device  100  is configured to generate a time delay from receiving an input signal from the input ETL to outputting a signal to the output ETL  14 . In various embodiments, the inert time delay device  100  is 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 device  100  comprises a housing  120  having a first end  122  and a second end  124 , a low energy (LE) ignition  130 , a primer  140 , and the spring damper system  110 . “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 ignition  130  is disposed at the first end  122  of the housing  120  and the primer  140  is disposed at the second end  124  of the housing  120 . The second end  124  is disposed opposite the first end  122 . In various embodiments, the housing  120  may be cylindrical, cuboidal, or the like. The spring damper system  110  is disposed within the housing  120  and configured to generate a predetermined time delay from receiving an ignition at LE or GG ignition  130  at first end  122  and releasing a firing pin  150  into the primer  140  at second end  124 . 
     In various embodiments, the spring damper system  110  comprises a first spring  111 , a second spring  112 , the firing pin  150 , a piston  160 , and a hydraulic chamber  170 . The housing  120  comprises a first chamber  121 , a second chamber  123 , and the hydraulic chamber  170  disposed between the first chamber  121  and the second chamber  123 . The housing  120  may further comprise a release chamber  125  disposed between the hydraulic chamber  170  and the second chamber  123 . 
     In various embodiments, the first spring  111  is disposed between a pressure plate  114  and a first wall  115 . The first wall  115  at least partially defines the first chamber  121  of the housing  120 . The first chamber  121  is defined by an inner surface of the LE or GG ignition  130 , a radially outer wall of the housing  120 , and an axial wall (i.e., first wall  115 ) of the housing. The hydraulic chamber  170  is disposed axially between the first wall  115  and a second wall  116  disposed distal to the first wall  115   
     The pressure plate  114  is disposed proximate (i.e., spaced apart from), the LE or GG ignition  130 . The first spring  111  may be disposed in a neutral state (i.e., neither compress nor extended). In various embodiments, in response to LE or GG ignition  130  being ignited, the LE or GG ignition  130  may generate a flame and pressure between the LE or GG ignition  130  and the pressure plate  114  in the first chamber  121 . In various embodiments, as described further herein, the pressure generated from the LE or GG ignition  130  results in a force being applied on the pressure plate  114  towards the second end  124  of the housing  120 , which results in the first spring  111  compressing and the pressure plate  114  translating axially towards the first wall  115 . 
     In various embodiments, the piston  160  comprises a piston head  162 , a first rod  164  and a second rod  166 . The first rod  164  extends axially away from the piston head  162  toward the first end  122  of the housing  120 . The second rod  166  extends axially away from the piston head  162  toward the second end  124  of the housing  120 . In various embodiments, the piston head  162  is disposed in the hydraulic chamber  170 . In this regard, the piston head  162  may further comprise apertures disposed therethrough to allow fluid communication between sides from one side of the piston head  162  to the other side of the piston head  162  during operation of the inert time delay device  100  as described further herein. In various embodiments, the piston  160  further comprises an engagement end  168  of the second rod  166  disposed distal to the piston head  162 . In various embodiments, the first rod  164  extends through first wall  115  into the first chamber  121 . Similarly, the second rod  166  extends through the second wall  116  into the second chamber  123 . 
     In various embodiments, the hydraulic chamber  170  may be sealed from the first chamber  121  and the second chamber  123  by any method known in the art, such as an elastomeric seal, a gasket, or the like. In this regard, a working fluid  172  disposed in the hydraulic chamber  170  is configured is fluidly isolated from the first chamber  121  and the second chamber  123  during operation of the spring damper system  110 . The working fluid  172  may be any working fluid, such as water, oil, air, or any other liquid or gas, etc. In various embodiments, the working fluid  172  may be chosen based on a desired viscosity and/or a desired predetermined time delay. In this regard, the structure of the inert time delay device  100  may be maintained and only a working fluid  172  may 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 spring  112  is disposed in the second chamber  123 . The second spring  112  is disposed axially between a third wall  117  of the housing  120  and a head  152  of the firing pin  150 . Similar to the first spring  111 , the second spring  112  may be in a natural state (i.e., neither compressed nor extended) upon installation. 
     In various embodiments, the firing pin  150  comprises the head  152  disposed proximate (i.e., spaced apart from) the primer  140  and a rod  154  extending away from the head  152  towards the first end  122  of the housing. In various embodiments, the firing pin  150  further comprises an engagement end  156  disposed on an end of the rod  154  that is distal to the head  152 . The engagement end  156  is configured to engage the engagement end  168  of second rod  166  of the piston  160 . 
     The engagement end  168  of piston  160  and the engagement end  156  of the firing pin  150  may be disposed in a channel  126  disposed axially through the third wall  117  and extending from the release chamber  125 . In this regard, the channel  126  may be sized and configured to maintain engagement between the engagement end  168  of the piston  160  and the engagement end  156  of the firing pin during operation, and the release chamber  125  may be sized and configured to facilitate disengagement between the engagement ends  156 ,  168  during operation of the spring damper system  110 . In this regard, the release chamber  125  has a first diameter that is greater than a second diameter defined by the channel  126 . 
     Referring now to  FIGS.  2  and  3   , a cross-sectional view of an initial sequence of the inert time delay device  100  is illustrated, in accordance with various embodiments. As shown in  FIG.  2   , a time delay sequence is initiated in response to the LE or GG ignition  130  receiving a pyrotechnic input supplied via input ETL  12 . In response to the LE or GG ignition  130  receiving the pyrotechnic input, the LE or GG ignition  130  may generate a low energy spark within the first chamber  121  between the pressure plate  114  and the LE or GG ignition  130 . In this regard, the pressure the LE or GG ignition  130  and creates an axial force on pressure plate  114 , causing the pressure plate to translate axially towards the first wall  115  and compress the first spring  111 . In various embodiments, the pressure plate  114  is configured to engage, and become coupled to, the first rod  164  of the piston  160 , as illustrated in  FIG.  3   . For example, the pressure plate  114  may comprise a receptacle configured to receive and lock to an end of the first rod  164 . In various embodiments, the first spring  111  is in a compressed state upon engagement of the pressure plate  114  with the first rod  164  of the piston  160 . Thus, once the force of the first spring  111  exceeds any remaining generated from the low energy spark of the LE or GG ignition  130 , the first spring  111  translates the pressure plate  114 , and the piston  160  axially towards the first end  122  of the housing  120  as illustrated in  FIG.  4   . 
     With reference now to  FIG.  4   , in response to the piston  160  translating axially towards the first end  122  of the housing  120 , the piston head  162  travels axially through the hydraulic chamber  170 . In this regard, the piston  160  is dampened by the working fluid  172  in the hydraulic chamber  170 . 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 head  162  travels axially through the hydraulic chamber  170 , the working fluid may flow through the piston head  162  from one axial side of the piston head  162  to a second axial side of the piston head  162 . 
     In various embodiments, in response to the piston  160  translating axially towards the first end  122  of the housing  120 , the second rod  166  of the of the piston  160  pulls the rod  154  of the firing pin  150  through the channel  126  of the housing  120 . In this regard, the engagement ends  156 ,  168  are pulled towards the release chamber  125  of the housing  120 . In doing so, the head  152  of the firing pin  150  begins to compress the second spring  112 , which begins to create stored potential energy within the second spring  112 . 
     Referring now to  FIG.  5   , in response to the piston head  162  of the piston  160  translating from a first axial side to a second axial side of the hydraulic chamber  170 , the engagement ends  156 ,  168  enter the release chamber  125  of the housing  120 . As mentioned previously herein, the release chamber  125  has a diameter that is greater than the channel  126  of the housing  120 . In this regard, in response to the engagement ends  156 ,  168  entering the release chamber  125 , the engagement ends  156 ,  168  are configured to disengage and release the firing pin  150  from the piston  160  as illustrated in  FIG.  6   , in accordance with various embodiments. 
     At the point of disengagement, the second spring  112  is compressed within the second chamber  123  between the head  152  of the firing pin  150  and an axial surface of the third wall  117 . Due to the compression, the second spring  112  comprises stored energy, which is released in response to disengagement of the engagement ends  156 ,  168 . 
     Referring now to  FIG.  6   , the second spring  112  translated the firing pin  150  axially towards the second end  124  of the housing  120  causing the head  152  of the firing pin  150  to contact the primer  140  igniting a respective propellent in the primer  140 , which in turn ignites an output ETL  14  and to complete a respective time delay. 
     In various embodiments, various aspects of the inert time delay device  100  may 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 spring  111  or second spring  112  to vary a respective time delay, a viscosity of working fluid  172  may be chosen based on a desired time delay, or the like. Similarly, an axial travel distance of the engagement ends  156 ,  168  may be varied or modified based on a desired time delay, or the like. In various embodiments, the mechanical aspects of the inert time delay device  100  may 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 device  100 , less testing, and/or lower cost, relative to typical time delay devices may be achieved. 
     Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure. The scope of the disclosure is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Different cross-hatching is used throughout the figures to denote different parts but not necessarily to denote the same or different materials. 
     Systems, methods and apparatus are provided herein. In the detailed description herein, references to “one embodiment,” “an embodiment,” “various embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments. 
     Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. 
     Finally, it should be understood that any of the above described concepts can be used alone or in combination with any or all of the other above described concepts. Although various embodiments have been disclosed and described, one of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. Accordingly, the description is not intended to be exhaustive or to limit the principles described or illustrated herein to any precise form. Many modifications and variations are possible in light of the above teaching.