Initiator with a slip plane between an ignition charge and an output charge
View Patent ↗A pyrotechnic initiator having an initiator including a relatively low monolithic ignition charge that is separated from an overlying output charge by an intermediary slip plane. The slip plane may simply be a non-integral junction between monolithic ignition and output charges, or it may be a junction between a monolithic ignition charge and a non-monolithic output charge, or it may be a void or barrier between the ignition and output charges.
1. An initiator comprising:
a) a header assembly including an eyelet, a top surface, and an exposed electrical initiating element on said top surface;
b) a monolithic solid ignition charge adjacent to said top surface of said header assembly, said ignition charge being adjacent to and in heat-transferring relationship with said electrical initiating element;
c) an output charge overlying said ignition charge;
an intermediary slip plane between said ignition charge and said output charge, wherein said slip plane is created by a lack of integral connection between said ignition charge and said output charge, wherein said ignition charge and said output charge are in immediate contact with each other over substantially all of said slip plane; and,
d) a charge can around said ignition charge and said output charge and hermetically attached to said header assembly so as to separate the interior contents of said can from the ambient environment exterior to said can.
2. The initiator subassembly of claim 1 , wherein said electrical initiating element is a bridgewire.
3. The initiator of claim 1 , wherein said output charge is non-monolithic and thus incapable of transmitting substantial lateral force components or torque to said ignition charge.
4. The initiator of claim 1 , wherein said ignition charge is formed from a slurry that includes a binder at less than five percent by weight and a solvent at between ten to thirty percent by weight.
5. The initiator of claim 4 , wherein said ignition charge is a dried centrifuged slurry having a height of no more than a millimeter.
6. The initiator of claim 1 , wherein said output charge is a monolithic solid mass.
7. The initiator of claim 6 , wherein both of said ignition charge and said output charge are formed of dried slurry.
8. The initiator of claim 1 , further comprising a charge sleeve within said charge can, said sleeve projecting upwardly above said top surface of said eyelet and circumferentially surrounding said ignition charge and said output charge.
9. The initiator of claim 8 , wherein said charge sleeve has a narrowed top end, and said charge has a largest outer diameter that is greater than the inner diameter of said narrowed top end of said sleeve.
10. The initiator of claim 8 , further comprising an ignition charge dam confining said ignition charge, said output charge having a diameter greater than that of said ignition charge.
11. A method for making an initiator, comprising the steps of:
a) providing a header assembly including an eyelet, a top surface, and an exposed electrical initiating element on said top surface;
b) providing a monolithic solid ignition charge adjacent to said top surface of said header assembly and adjacent to and in a heat-transferring relationship with said electrical initiating element;
c) loading an output charge on top of said ignition charge;
d) providing an intermediary slip plane between said ignition charge and said output charge, wherein said slip plane is created by a lack of integral connection between said ignition charge and said output charge, wherein said ignition charge and said output charge are in immediate contact with each other over substantially all of said slip plane; and,
e) placing a charge can around said ignition charge and said output charge and hermetically attaching said charge can to said header assembly so as to separate the interior contents of said can from the ambient environment exterior to said can.
12. The method of claim 11 , wherein step b) and step c) each include the step of slurry-loading a charge slurry.
13. The method of claim 11 , further comprising the step of axially spinning said header assembly.
14. The method of claim 11 , further comprising the step of providing a charge sleeve within said charge can and around said ignition charge and output charge.
15. The method of claim 11 , wherein said electrical initiating element is a bridgewire.
16. The method of claim 11 , wherein said ignition charge is formed from a slurry that includes a binder at less than five percent by weight and a solvent at between ten to thirty percent by weight.
17. The method of claim 16 , wherein said ignition charge is a dried centrifuged slurry having a height of no more than a millimeter.
18. The method of claim 11 , wherein said output charge is a monolithic solid mass.
19. The method of claim 14 , wherein both of said ignition charge and said output charge are formed of dried slurry.
20. The method of claim 14 , wherein said charge sleeve has a narrowed top end, and said charge has a largest outer diameter that is greater than the inner diameter of said narrowed top end of said sleeve.
21. The initiator made by the method of claim 11 .