Patent Abstract:
The present invention relates to an improved apparatus for safely igniting a pyrotechnic device such as a flare which is suspended by a parachute following deployment from an air craft. More specifically, the present invention relates to a two stage ignition train mechanism for use with parachute suspended illumination flares with an in-line firing pin and physical safety mechanism which blocks movement of the firing pin until the parachute is deployed. The present invention also discloses an embodiment of a two stage ignition train mechanism for use with parachute suspended illumination flares with out-of-line firing pin and physical safety mechanism which blocks the firing pin from striking the primer until the parachute is deployed.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application relates to U.S. Provisional Patent Application Ser. No. 61/292,443 filed Jan. 5, 2010, entitled Ignition Train Mechanism for Illumination Flare, and to U.S. Provisional Patent Application Ser. No. 61/368,908 filed Jul. 29, 2010, also entitled Ignition Train Mechanism for Illumination Flare and the contents thereof are incorporated fully by reference hereto. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     REFERENCE TO A “MICROFICHE APPENDIX” 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     The present invention relates to an improved apparatus for safely igniting a pyrotechnic device such as a flare which is suspended by a parachute following deployment from an air craft. More specifically, the present invention relates to alternative embodiments of a multiple stage ignition train mechanism for use with parachute suspended illumination flares, one embodiment with an in-line firing pin and the other with an out-of-line firing pin which moves in-line for firing, and a physical safety mechanism which blocks movement of the firing pin until the parachute is deployed. 
     Pyrotechnic devices such as flares produce brilliant light or intense heat without an explosion. Some flares are used for illumination purposes, for example to provide light on a battle field to better identify potential targets or during a search and rescue mission to assist in locating the objective. Parachute suspended flares provide maximum illumination time over a large area. Many of these illumination flares are deployed from air craft, for example standard U.S. Air Force illumination flares LUU-2 and LUU-19. The LUU-2 emits visible light while the LUU-19 emits infrared light only and is used with night vision goggles. These particular flares are designed to burn approximately five minutes. At an altitude of 1000 feet, the LUU-2 illuminates a circle on the ground of about 500 meters. The flare includes a timer which deploys the parachute and ignites the main candle. 
     Because illumination flares are designed to emit a large amount of light or energy for a significant length of time, they are often large and heavy. For example, the LUU-2 and LUU-19 are 36 inches long with a 4¾ inch outer diameter and weigh approximately 35 pounds each. It is critical that the flare ignite at the appropriate time—at a pre-set time after ejection from the aircraft—and not before. Accidental ignition prior to ejection or during loading and handling have serious repercussions including damage to equipment and personnel in the ignition area. 
     It is an objective of the present invention to provide a two-stage ignition train mechanism including a safety mechanism and an ignition mechanism, said safety mechanism incorporating a physical barrier prohibiting forward movement of the firing pin toward the primer and firing mechanism until the parachute is deployed. The ignition mechanism utilizes forces from parachute deployment to initiate the ignition sequence. There is no pre-load on the firing mechanism with the in-line design. It is another objective of the present invention to provide a two stage ignition train mechanism having an ignition mechanism which in a second embodiment is initially out-of-line of the firing axis and is rotated to an in-line position during the descent of the flare housing. The in-line firing pin design creates a more reliable, robust, controllable and consistent ignition sequence, however, by providing a mechanism which brings the initially out-of line firing mechanism in-line during the descent of the flare, added safety to those handling and equipment carrying the flare is achieved. With the inventive out-of-line firing mechanism, there is no pre-load on the firing mechanism. The inventive out-of-line design incorporates the use of shear pins to prevent rotation of the firing mechanism until the predetermined activation force is applied to the mechanism to shear the pin that holds the firing pin housing in place. Further, the end of the lanyard assembly is held in place to block forward motion of the firing pin until a second shear pin is sheared by a predetermined force, sufficient to cock the firing pin and bring the firing mechanism in-line with the primer compartment hole is reached. This is achieved safely with the post-launch rotation to the in-line firing position, achieving a “delayed” alignment with the firing pin and primer to the pellet cavity through the added physical barrier of the safety mechanism. Another objective of the present invention is to design a two stage ignition train system which, when dropped from forty feet, will not trigger the ignition sequence by inertia or incidental deployment of the timer or ignition train assembly. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention relates to an improved apparatus for safely igniting a pyrotechnic device such as a flare which is suspended by a parachute following deployment from an air craft. More specifically, the present invention relates to a two stage ignition train mechanism for use with parachute suspended illumination flares with an out-of-line firing pin and physical safety mechanism which blocks movement of the firing pin until the parachute is deployed. With the firing pin initially off-set from the firing axis, the primer assembly is displaced from the pellets and significantly reduces the possibility of an electro-static discharge activation of the primer from igniting the pellets. The present invention also relates to a two stage ignition train mechanism for use with parachute suspended illumination flares with an in-line firing pin and physical safety mechanism which blocks movement of the firing pin until the parachute is deployed. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIGS. 1  though  9  illustrate the in-line firing mechanism of the present invention and  FIGS. 10 through 21  illustrate the out-of-line firing mechanism of the present invention. 
         FIG. 1  is a cross sectional view of the housing for a parachute suspended illumination flare. 
         FIG. 2  is a cross sectional view of the front or forward end of the housing for a parachute suspended illumination flare showing the bulkhead. 
         FIG. 3  is a cross sectional view of the back or aft end of the housing for a parachute suspended illumination flare. 
         FIG. 4   a  is a prospective view of the ignition train housing including one embodiment of the two stage ignition mechanism of the present invention. 
         FIG. 4   b  is a prospective view of the ignition train housing including one embodiment of the two stage ignition mechanism of the present invention including the cover for the ignition train housing. 
         FIG. 5   a  is a side view of the ignition mechanism housing and safety mechanism housing of the two stage ignition mechanism of one embodiment of the present invention. 
         FIG. 5   b  is another side view of the ignition mechanism housing and safety mechanism housing of the two stage ignition mechanism of one embodiment of the present invention. 
         FIG. 6  is a cross sectional view of the ignition mechanism housing and safety mechanism housing of the one embodiment of the two stage ignition mechanism of the present invention. 
         FIG. 7  is a cross sectional view of the ignition train housing, including a cross sectional view of the safety mechanism housing, of one embodiment of the two stage ignition mechanism of the present invention. 
         FIG. 8  is a cross sectional view of the ignition train housing, including a cross sectional view of the ignition mechanism housing, of one embodiment of the two stage ignition mechanism of the present invention. 
         FIG. 9  is a cross sectional view of the ignition mechanism housing of one embodiment of the two stage ignition mechanism of the present invention. 
         FIG. 10   a  is a prospective view of the ignition train housing of a second embodiment of the two stage ignition mechanism of the present invention. 
         FIG. 10   b  is a prospective view of the ignition train housing of a second embodiment of the two stage ignition mechanism of the present invention including the cover for the ignition train housing. 
         FIG. 10   c  is a cross sectional view of the housing for a parachute suspended illumination flare showing details of the bulkhead, raceway channel and main candle compartment. 
         FIG. 10   d  is a cross sectional view of the back or aft end of the housing for a parachute suspended illumination flare. 
         FIG. 10   e  is a cross sectional view of the front or forward end of the housing for a parachute suspended illumination flare showing the bulkhead and raceway channel. 
         FIG. 11   a  is an exploded view of a second embodiment of the ignition train mechanism of the present invention. 
         FIG. 11   b  is a prospective view of a portion of a second embodiment of the ignition train mechanism of the present invention showing the ignition canister and ignition opening. 
         FIG. 11   c  is a prospective view of a portion of a second embodiment of the ignition train mechanism of the present invention showing the ignition canister, ignition opening. and aluminum foil tape as an electrostatic barrier. 
         FIGS. 12   a  and  12   b  are prospective views of a second embodiment of the ignition train mechanism of the present invention showing the inside of the housing with the firing pin mechanism removed. 
         FIGS. 13   a ,  13   b ,  13   c , and  13   d  are pictorial views of the firing pin of a second embodiment of the ignition train mechanism of the present invention. 
         FIG. 14   a  is a side view of the firing mechanism housing of a second embodiment of the ignition train mechanism of the present invention. 
         FIG. 14   b  is a cross sectional top view of the firing mechanism housing of a second embodiment of the ignition train mechanism of the present invention. 
         FIG. 14   c  is a cross sectional side view of the firing mechanism housing of a second embodiment of the ignition train mechanism of the present invention. 
         FIG. 14   d  is a bottom view of the firing mechanism housing of a second embodiment of the ignition train mechanism of the present invention. 
         FIG. 15   a  is a partial view of the inside of the housing of a second embodiment of the ignition train mechanism of the present invention showing the lanyard cable guides. 
         FIG. 15   b  is a view of the lanyard cable guide of a second embodiment of the ignition train mechanism of the present invention. 
         FIGS. 16 through 21  are top views of a second embodiment of the ignition train mechanism of the present invention showing the sequence of motion of the firing mechanism from initial movement at the unarmed, out-of-line position through ignition of the primer and pellets at the firing, in-line position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to  FIGS. 1 through 9 , the ignition train housing  1  is positioned at the aft or back end of the interior of the illumination flare housing  100 . A timer (not shown) is positioned in the timer compartment  105  at the forward or front end of the illumination flare housing  100 . The timer has a pre-set mechanism which controls the ejection of the parachute from the illumination flare housing  100 . The parachute is positioned below the timer in the parachute compartment  110  of the illumination flare housing  100 . The bulkhead  115  is positioned below the parachute compartment  110  and separates the parachute compartment  110  and the main candle compartment  120 . The bulkhead has two riser holes  114  drilled through its surface. There are two cables called risers (not shown) which connect the parachute to the bulkhead. One end of each riser is connected to the parachute and the other end of each riser is attached to one of the riser holes  114  with a fastener such as a screw or bolt assembly. 
     Referring still to  FIG. 1 , the main candle compartment  120  contains the flare composition (not shown). A first raceway channel  116  (not shown) and a second raceway channel  117  extend longitudinally down the side of the main candle compartment  120  between the bulkhead  115  and the ignition train housing  1 . Referring now to  FIG. 2 , the bulkhead has a first and a second ignition train cable hole  113  (only one shown) positioned adjacent to each raceway channel  116 ,  117  (shown in  FIG. 3 ). 
     Referring now to  FIG. 3 , a safety cable  118  is attached to a first riser (not shown) and extends through the first ignition train cable hole  112  (not shown) and longitudinally along the side of the illumination flare housing from the bulkhead to the ignition train housing  1  via the interior of the first raceway channel  116 . The safety cable  118  enters the ignition train housing  1  via the safety mechanism opening  2  in the ignition train housing  1 . Referring now to  FIG. 3 , an ignition cable  119  is attached to the first riser (not shown) and extends through the second ignition train cable hole  113  ( FIG. 2 ) and longitudinally along the side of the illumination flare housing from the bulkhead to the ignition train housing  1  via the interior of the second raceway channel  117 . The ignition cable  119  enters the ignition train housing  1  via the ignition mechanism opening  3  in the ignition train housing  1 . When the parachute is ejected from the illumination flare housing  100 , the first and second risers extend to their full length. The tension from the fully extended riser puts tension on the safety cable  118  and ignition cable  119  which are attached to one of the risers. 
     Referring now to  FIG. 4   a , the ignition mechanism housing  5  is affixed to the base of the ignition train housing  1 . A first end of said ignition mechanism housing  5  is aligned with the ignition cable opening  3  such that said ignition cable  119  enters said first end of said ignition mechanism housing  5 . A second end of said ignition mechanism housing  5  is aligned with said ignition primer compartment  10  ( FIG. 8 ) and an ignition canister  15  such as a Peket canister. Referring now to  FIG. 4   b , a cover  1   a  is affixed to the top of the ignition train housing  1 . The cover  1   a  is adjacent to the main candle compartment  120  of the illumination flare housing  100  ( FIG. 1 ). The cover  1   a  has at least three openings, a first opening  3   a  aligned with the safety cable opening  3 , a second opening  2   a  aligned with the ignition cable opening  2 , and a third opening  15   a  aligned with said ignition canister  15 . The ignition canister  15  has an open top which is affixed to the cover  1   a  such that the heat of combustion may pass through to the main candle compartment  120  thereby igniting the main candle of the illumination flare via the ignition sequence described below. 
     As shown in  FIGS. 5   a  and  5   b , safety mechanism housing  20  intersects the ignition mechanism housing  5 . A first end of said safety mechanism housing  20  is aligned with the safety cable opening  2  ( FIG. 4   a ) such that said safety cable  118  enters said first end of said safety mechanism housing  20 . As shown in  FIG. 8 , said safety mechanism housing is hollow and passes through an opening  12  in a firing pin  8 . Referring now to  FIGS. 6 and 7 , a safety fitting  21  is located inside said safety mechanism housing  20 . Said safety fitting  21  is secured to said safety mechanism housing  20  with a safety shear pin  22 . Said safety shear pin  22  passes through a hole in said housing  20  and in said safety fitting  21 . A first end of said safety fitting  21  is engaged with the opening  12  in the firing pin  8  prohibiting axial movement of said firing pin  8 . The safety cable  118  is attached to a second end of said safety fitting  21 . The safety shear pin  22  is designed to break at a pre-set force. When the parachute is deployed from the illumination flare housing  100  and the risers are fully extended thereby putting tension on the safety cable  118 , the safety fitting  21 , and the shear pin  22 . Once the shear pin  22  experiences the pre-set amount of force, the shear pin  22  breaks and the safety fitting  21  becomes disengaged with the opening  12  in the firing pin  8  thereby allowing axial movement of the firing pin  8 . 
     Referring now to  FIGS. 8 and 9 , an ignition fitting  6  is located inside the opening  5   a  of said ignition mechanism housing  5  at said first end of said housing  5 . Said ignition fitting  6  is secured to a first end of a firing pin  8  with an ignition shear pin  7 . Said ignition shear pin  7  passes through a hole in said firing pin  8  and in said ignition fitting  6  such that when the fitting  6  moves toward the opening  5   a , the firing pin also moves toward the opening  5   a . The ignition shear pin  7  is designed to break at a pre-set force. The ignition cable  119  is attached to a first end of said ignition fitting  6 . The firing pin  8  is located inside and axially aligned with said ignition mechanism housing  5 . The firing pin  8  extends longitudinally through said ignition mechanism housing  5  to the second end of said ignition mechanism housing  5 . Said second end of said ignition mechanism housing  5  has an opening which is adjacent to said ignition primer compartment  10 . Said primer compartment  10  is attached to said ignition canister  15 . Said second end of said firing pin  8  is aligned with said opening in said second end of said ignition mechanism housing  5  and has a shape such that it is capable of engaging with said ignition primer (not shown). Thus said firing pin  8  is in-line with said ignition primer. 
     A spring  9  surrounds a portion of the firing pin  8  as shown in  FIGS. 8 and 9 . The ignition mechanism housing  5  has a stop  9   a  adjacent the opening  5   a . The stop  9   a  limits the movement of the firing pin  8  in the direction of the opening  5   a  thereby compressing the spring  9  upon such movement. 
     When the parachute is deployed from the illumination flare housing  100  and the risers are fully extended thereby putting tension on the safety cable  118 , the safety fitting  21 , and the shear pin  22 . Once the shear pin  22  experiences the pre-set amount of force, the shear pin  22  will break and the safety fitting  21  will become disengaged with the opening  12  in the firing pin  8  thereby allowing axial movement of the firing pin  8 . The fully extended riser also puts tension on the ignition cable  119 , the ignition fitting,  6 , the ignition shear pin  7 , the spring  9 , and the firing pin  8 . Additionally, the movement of the firing pin  8  towards the first opening  5   a  of the housing  5  compresses the spring  9 . When the tension on the ignition shear pin  7  exceeds the pre-set force, the ignition shear pin  7  breaks and the firing pin  8  and ignition fitting  6  become separated. The ignition fitting  6  continues its backwards movement away from the primer compartment  10 . The firing pin  8 , due to the energy stored in the spring  9 , is propelled forward towards the primer compartment  10  and strikes the primer contained in the primer compartment  10  creating a spark. 
     The ignition primer compartment  10  contains an ignition primer to create a spark when struck by the firing pin  8 . The ignition primer can be any ignition primer composition commonly used with pyrotechnic flares, for example CCI Inc. No. 200 Rifle Primer. The ignition primer compartment is connected to the ignition canister  15  such that the heat from the primer compartment  10  is transferred to ignition canister  15 . The bottom portion of the ignition canister  15  contains ignition pellets which are ignited by the heat from the ignition primer compartment  10 . The ignition pellets can be made of any composition of pyrotechnic material commonly used with pyrotechnic flares. For example BKNO 3  pellets which are primarily made of potassium nitrate. The top of the ignition canister  15  is open and connected to the main candle compartment  120  via opening  15   a . The lower surface of the main candle compartment  120  contains an ignition compound which is ignited by the heat from the ignition pellets. The heat from the ignition canister  15  is transferred to the main candle compartment  120  and ignites the ignition compound. The ignition compound can be made of any composition of pyrotechnic material commonly used with pyrotechnic flares. The remainder of the main candle compartment contains the main candle flare composition. The heat from the ignition compound ignites the main candle composition of the flare. The main candle composition can be made of any composition of pyrotechnic material commonly used with pyrotechnic flares. 
     Referring now to  FIGS. 10 through 21 , a second embodiment of the ignition train mechanism is disclosed. As shown in  FIG. 10   c , the ignition train housing  201  is positioned at the aft or back end of the interior of the illumination flare housing  100 . A timer (not shown) is positioned in the timer compartment  105  at the forward or front end of the illumination flare housing  100 . The timer has a pre-set mechanism which controls the ejection of the parachute from the illumination flare housing  100 . The parachute is positioned below the timer in the parachute compartment  110  of the illumination flare housing  100 . The bulkhead  115  is positioned below the parachute compartment  110  and separates the parachute compartment  110  and the main candle compartment  120 . The bulkhead has two riser holes  114  drilled through its surface. There are two cables called risers (not shown) which connect the parachute to the bulkhead. One end of each riser is connected to the parachute and the other end of each riser is attached to one of the riser holes  114  with a fastener such as a screw or bolt assembly. 
     Referring still to  FIG. 10   c , the main candle compartment  120  contains the flare composition (not shown). A raceway channel  235  extends longitudinally down the side of the main candle compartment  120  between the bulkhead  115  and the ignition train housing  201 . Referring now to  FIG. 10   e , the bulkhead has an ignition train cable hole  236  positioned adjacent to the raceway channel  235 . A lanyard cable  220  (not shown) is attached to a riser (not shown) and extends through the lanyard cable hole  236  and longitudinally along the side of the illumination flare housing from the bulkhead to the ignition train housing  201  via the interior of the raceway channel  235 . The lanyard cable  220  traverses the ignition train housing cover  201   a  through a hole  250  in the cover  201   a  ( FIG. 10   b ) and enters the ignition train housing  201  through the lanyard cable guide  251   a  ( FIG. 12   a ). The lanyard cable guides  251   a  and  251   b  position the cable such that it extends through the ignition train housing  201  to the firing mechanism housing  205  where it is engaged with the housing  205  (See  FIGS. 14   a, b , and  c ). When the parachute is ejected from the illumination flare housing  100 , the risers extend to their full length. The tension from the fully extended riser puts tension on the lanyard cable  220  which is attached to one of the risers. 
     Referring now to  FIGS. 10   a  and  10   b  which include ignition train mechanism housing  201  and ignition train mechanism cover  201   a , within the housing  201  is the firing mechanism housing  205 , containing the firing pin  208 , primer cup  206  and compression spring  209  (further illustrated in  FIGS. 14   a ,  14   b , and  14   c ). Housing  205  is pivotally attached to the base of said housing  201  through pivot pin  202  to rotate in an arc between the initial unarmed position (shown in  FIG. 16 ) at stop post  235  and the final firing position (shown in  FIG. 21 ) at stop post  230 , where the firing pin  208  has impacted the primer, creating a spark, igniting the pellets, and igniting the flare. 
       FIG. 11   a  is an exploded view illustrating the operative components of the ignition train housing and their relative position and function. The Cover  201   a  in  FIG. 11   a  is adjacent to the main candle compartment  120  of the illumination flare housing  100 . The Cover  201   a  has at least 2 openings; a first opening aligned with the raceway channel  235  and a second opening aligned with the ignition canister  215 . The ignition canister  215  is open such that the heat of combustion may pass through the cover opening  215   a  to ignite the main candle of the illumination flare via the ignition sequence described below. 
     Referring now to  FIGS. 10   a ,  12   a , and  12   b , the base of the ignition train mechanism housing  201  is shown.  FIG. 10   a  includes the firing mechanism housing  205  which is attached at a first end to the ignition train housing  201  by pivot pin  202  and is movable about said pivot pin  202 . The firing mechanism housing  205  has a shear pin fitting  245  positioned at a second end of the firing mechanism housing  205  (see also  FIG. 14   b ). A shear pin  227  designed to break at a predetermined force is affixed to the base of the ignition mechanism housing  201  (See  FIG. 12   a ). In the initial, unarmed, out-of-line position (see  FIG. 16 ), shear pin  227  is engaged with shear pin fitting  245  which locks the firing mechanism housing  205  in the initial, out-of-line position. A first stop  235  is affixed to said base of said housing  201  and adjacent to said firing mechanism housing  205  in its initial, out-of-line position and prevents the firing mechanism housing  205  from traveling past the initial, out-of-line position. 
     Still referring to  FIG. 10   a , the firing mechanism housing  205  has a lanyard opening  260  positioned at a second end of the firing mechanism housing  205  opposite said pivot pin  202  (see also  FIGS. 14   a  and  14   b ). A lanyard fitting  261  intersects the lanyard opening  260  such that a portion of the lanyard fitting  261  is inside the firing mechanism housing  205  to serve as a mechanical block as described below. The lanyard fitting  261  is secured in position by a lanyard shear pin  222  that intersects the firing mechanism housing  205  and the lanyard fitting  261 . The lanyard cable  220  is attached to the lanyard fitting  261 . The lanyard shear pin  222  is designed to break at a predetermined force. The break forces for the shear pins  222  and  227  are developed based on the forces to actuate the firing pin  208  using the cam follower pin  226  and compression spring  209  as described in more detail in the following sections. For example, the lanyard shear pin  222  is designed to break when the parachute is fully deployed and has descended to an altitude where the flare should be illuminated. 
     When the parachute is deployed and the risers are fully extended, the tension on the risers puts a tension on the lanyard cable  220  and on the shear pin  222 . Likewise, there is tension on the shear pin  227 . Shear pin  227  is designed to break with less force than lanyard shear pin  222 ; therefore, when the parachute is deployed, shear pin  227  breaks first and the firing mechanism housing  205  is pulled from the initial, out-of-line position towards the final, in-line position (see  FIG. 21 ) by the lanyard cable  220 . A second stop  230  is affixed to said base of said housing  201  and adjacent to said firing mechanism housing  205  in its final, in-line position and prevents the firing mechanism housing  205  from traveling past the final, in-line position. The second stop  230  causes the riser tension to increase to a force sufficient to break shear pin  222  while the firing pin  208  and primer cup  206  are in-line with the ignition canister  215 . 
     Still referring to  FIGS. 10   a ,  12   a , and  12   b , the ignition canister  215 , which contains the ignition material to be ignited by the primer, is disposed within the housing  201 . The pivot pin  202  is attached to the base of said housing  201  opposite the ignition canister  215 . In some embodiments, a barrier wall  234  is adjacent ignition canister  215  and intermediate to said ignition canister  215  and said pivot pin  202 . The second end of the firing mechanism housing  205  is adjacent to the barrier wall  234 . Stops  235  and  230  are affixed to the base of said housing  201  at either end of the arc shaped path traveled by the firing mechanism housing  205 . The second end of the firing mechanism housing  205  can pivot between stop posts  230  and  235  about said pivot pin  202  when the shear pin  227  is broken. The shear pin  227  provides added safety as it holds the firing mechanism in an unarmed, out-of-line position thereby significantly reducing the possibility of accidental firing of the mechanism. 
     As shown in  FIG. 16 , the ignition train housing  201  includes a barrier wall  234  to block the direct path between the primer  206  and the ignition canister  215 . The barrier wall  234  has an ignition opening  240  adjacent to the ignition canister  215  (see  FIG. 11   b ). When the firing mechanism housing  205  is in its final, in-line position (see  FIG. 21 ), the second end of the housing  205  and the primer cup  206  are adjacent to the ignition opening  240 . As shown in  FIG. 11   c , in other embodiments, a thin electrostatic barrier aluminum foil tape  233  is placed over the opening  240  in the barrier wall  234  as a safety feature. In the event the ignition primer  206  is ignited unintentionally due to electrostatic discharge (ESD), the primer energy will not reach and ignite the pellets in the ignition canister  215 . In the event the primer  206  is unintentionally ignited due to ESD, the energy must travel a longer path around the pivot end  202  of the ignition mechanism housing  205  before reaching the aluminum tape  233  covering the path to the ignition canister  215 . 
     Referring now to  FIG. 11   a , the firing mechanism housing  205  contains the primer cup  206 , the firing pin  208 , the compression spring  209 , washer  237 , and retaining ring  237   a . The firing pin  208  is slideably disposed inside and axially aligned with the firing mechanism housing  205 . The firing pin  208  has a striking tip  208   a  at one end of the firing pin  208 . The striking tip  208   a  is adjacent to the second end of the firing mechanism housing  205 . The second end of the firing mechanism housing  205  has an primer opening  241  which is aligned with the ignition opening  240  in the barrier wall  234  when the firing mechanism housing  205  is in the final, in-line position ( FIG. 21 ). The primer cup  206  is positioned in and affixed to the primer opening  241 . The primer cup  206  is axially aligned with the striking tip  208   a  such that the striking tip  208   a  fits inside the primer cup  206  ( FIGS. 14   b ,  14   c  and  21 ) and is capable of striking the center of the primer cup  206 . 
     The primer cup  206  contains an ignition primer to create a spark when struck by the firing pin  208 . The ignition primer can be any ignition primer composition commonly used with pyrotechnic flares, for example CCI Inc. No. 200 Rifle Primer. The primer cup  206  is aligned with the ignition opening  240  and the ignition canister  215  when the firing mechanism housing  205  is in the final, in-line position ( FIG. 21 ). When the firing pin  208  strikes the primer cup  206 , a spark is created igniting the ignition primer composition. The heat from the primer cup  206  is transferred through the ignition opening  240  to ignition canister  215 . In embodiments including an electrostatic barrier, the electrostatic barrier  233  is destroyed or burned by the energy and heat from the primer  206 . 
     The bottom portion of the ignition canister  215  contains ignition pellets which are ignited by the heat from the primer cup  206 . The ignition pellets can be made of any composition of pyrotechnic material commonly used with pyrotechnic flares. For example BKNO 3  pellets which are primarily made of potassium nitrate. The top of the ignition canister  215  is open and connected to the main candle compartment  120  via opening  215   a  ( FIGS. 10   b ,  10   c , and  10   d ). The lower surface of the main candle compartment  120  contains an ignition compound which is ignited by the heat from the ignition pellets. The heat from the ignition canister  215  is transferred to the main candle compartment  120  and ignites the ignition compound. The ignition compound can be made of any composition of pyrotechnic material commonly used with pyrotechnic flares. The remainder of the main candle compartment contains the main candle flare composition. The heat from the ignition compound ignites the main candle composition of the flare. The main candle composition can be made of any composition of pyrotechnic material commonly used with pyrotechnic flares. 
     Referring now to  FIGS. 11   a ,  14   b  and  14   c , a compression spring  209  is disposed within the firing mechanism housing  205  adjacent to the first end of the firing mechanism housing  205 . A washer  237  and retaining ring  237   a  are disposed intermediate to the spring  209  and the housing  205 . The compression spring  209  is axially aligned and slideably engaged with the firing pin  208 . The firing pin  208  has at least one spring stop  208   b  which contact the forward end of the spring  209  such that when the firing pin  208  moves rearwardly towards the pivot point at the first end of the firing mechanism housing  205 , the spring  209  is compressed. The spring  209  is not preloaded, being compressed only after the ignition sequence is started, which provides for additional safety. As the firing pin  208  travels rearward inside the housing  205 , the spring  209  is compressed against the washer  237 , providing the energy to the firing pin  208  to ignite the primer  206  when the firing pin  208  is released. 
     Referring now to  FIGS. 13   a  and  13   b , the bottom side of the firing pin  208  has a cam follower passage (slot)  224  which allows for rearward motion of the firing pin  208  and compression of the spring  209 . The bottom side of the firing mechanism housing  205  has a cam follower opening  255  ( FIG. 14   d ). When assembled, the cam follower passage  224  fits over the cam follower opening  255 . The cam follower pin  226  is affixed to the base of the housing  201  ( FIGS. 12   a  and  12   b ). When the assembled firing mechanism housing  205  is installed in the housing  201 , the cam follower pin  226  is inserted into the cam follower opening  255  and cam follower passage  224  ( FIG. 16 ). As shown in  FIG. 16 , the cam follower pin  226  is adjacent to the forward edge of the cam follower passage  228  when the firing mechanism housing  205  is in the initial, out-of-line position. The forward edge  228  is closer to the first end of the firing mechanism housing  205  than the rear edge  229 . As the housing  205  is pulled by the lanyard cable  220  and rotates about the pivot pin  202 , the cam follower passage  224  travels along the cam follower pin  226  from the forward edge  228  towards the rear edge of the cam follower surface  229  thereby forcing the firing pin to slide backwards within the housing  205  towards the first end of the firing mechanism housing  205 . As the firing pin  208  slides rearward, the spring stops  208   b  contact the spring  209  and the spring  209  is compressed thereby cocking the firing pin. ( FIGS. 16-21 ) At a certain position of the pivotal movement of the firing mechanism housing  205 , the firing pin  208  slides off the cam follower pin  226  thereby releasing the firing pin  208  and the compressed spring  209 . ( FIG. 19 ). The energy stored in the spring  209  is transferred to the firing pin  208  which travels forward and strikes the primer in the primer cup  206  creating a spark to ignite the pellets in the ignition canister  215 . 
     Referring now to  FIG. 14   a , in some embodiments an alignment pin  231  is disposed in alignment hole  231   a  in the top of the firing mechanism housing  205  and protrudes into the inside of the housing  205 . Referring now to  FIG. 13   d , the firing pin  208  has an alignment slot  232  disposed longitudinally on the firing pin  208  which is at least as long as the travel distance of the firing pin  208  within the housing  205 . The alignment pin  231  fits into the slot  232  when the firing pin  208  is disposed within the housing  205 . The alignment pin  231  prevents the firing pin  208  from rotating within the housing  205  after the ignition train mechanism is actuated. This is important to keep the cam follower passage  224  correctly oriented so the cam follower pin  226  and the cam follower passage  224  are engaged at the correct position. This results in a more repeatable rearward travel distance by the firing pin  208  and compression of the spring  209 . 
     Referring now to  FIG. 13   c , in some embodiments the firing pin  208  has a locking recess  270  at the end of the firing pin with the striking tip  208   a  which provides an additional safety measure. The locking recess  270  is substantially aligned with the lanyard opening  260 . The lanyard fitting  261  protrudes into the internal cavity of the firing mechanism housing  205  and fits into the locking recess  270  thereby acting as a mechanical block to prevent the firing pin  208  from striking the primer  206  until the parachute is deployed initiating the ignition train firing sequence. Once a predetermined amount of force is applied to the lanyard shear pin  222  when the firing mechanism housing  205  is in the final, in-line position, the lanyard shear pin  222  breaks and the lanyard fitting  261  is pulled from the lanyard opening  260  thereby removing the mechanical block leaving the firing pin  208  free to strike the primer  206  ( FIGS. 20 and 21 ). 
       FIGS. 16 through 21  illustrate the components and articulation of the firing pin housing  205  from the initial, locked, unarmed position (out-of-line) to the final, firing position (in-line). This embodiment includes a spring actuated firing pin  208 , wherein the spring  209  is loaded, or compressed, through the articulation of the housing  205  toward the ignition canister  215 . The loading is enabled by the opening of the parachute attached to the flare housing  100  wherein fully extended risers put tension on the lanyard assembly  220  causing the shear pin  227  to shear and release the housing  205 . As the housing  205  rotates about pivot point  202 , the cam follower passage (slot)  224  follows the cam follower pin  226  in a relative rearward travel (toward pivot point  202 ) whereby spring  209  is compressed and firing pin  208  is retracted toward the ultimate firing position.  FIG. 18  illustrates the further loading of the spring  209  whereby the firing pin  208  and primer  217  are approaching alignment with the ignition canister  215 . Forward edge  228  of the cam follower passage  224  is now approaching the cam follower pin  226 . 
       FIGS. 19 through 21  illustrate the sequence of actions as the cam follower pin  226  travels off of the cam follower passage  224  and “releases” the firing pin  208 . The energy of the spring  209  causes the firing pin  208  to begin to travel toward the primer  206 . At  FIG. 20 , the housing  205  has reached stop post  230  to limit the rotation of the housing  205 . At this point the cam follower pin  226  has released the firing pin  208  allowing it to accelerate its movement toward the primer  206 . Because of the tension on the lanyard cable assembly  220  from the parachute opening, the shear pin  222  is sheared and the lanyard assembly fitting  261  is pulled out of the firing pin housing  205  enabling the firing pin  208  to advance to strike the primer  206  and ignite the pellets in the ignition canister  215  as illustrated in  FIG. 21 . While a straight diagonal cam follower passage  224  is shown, it should be evident to those skilled in the art that other than straight line cam follower passages are within the scope of this invention. Curved cam follower passages can offer varying activation force profiles during the activation of the firing mechanism and may be beneficial to use depending on the force and rate of mechanism activation desired. 
     Thus, it is seen that the disclosed embodiments of two stage ignition train mechanisms for use with parachute suspended illumination flares of the present invention readily achieves the ends and advantages mentioned as well as those inherent therein. While certain preferred embodiments of the invention have been illustrated and described for the purposes of the present disclosure, numerous changes in the arrangement and construction of parts may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present invention as defined by the following claims.

Technology Classification (CPC): 5