Standalone ignition subassembly for detonators

Abstract

A standalone ignition subassembly designed for ready incorporation into pyrotechnic detonators.

What is claimed is:  
     
         1 . A standalone ignition subassembly for use in a detonator that includes a shell and a detonator charge within said shell, said ignition subassembly having a substantially cylindrical body with an initiator end and a trigger end, and comprising: 
 a) a body portion having an outer diameter selected to closely match the inner diameter of a standard detonator shell;    b) a hermetically sealed ignition element at said initiator end; and,    c) a trigger means for causing said ignition element to ignite in response to an ignition signal, at least a portion of said trigger means being at said trigger end.    
     
     
         2 . The subassembly of  claim 1 , wherein said ignition element includes an ignition charge having an explosive energy sufficient to cause the detonation of a selected range of detonator charges when said ignition subassembly is secured in the detonator shell and said ignition element is ignited.  
     
     
         3 . The subassembly of  claim 1 , wherein said ignition element includes a charge enclosure that is hermetically sealed and substantially filled with an ignition charge.  
     
     
         4 . The subassembly of  claim 3 , wherein said ignition element includes a glass-to-metal header having a sealed feedthrough, and further includes a metallic can around said ignition charge.  
     
     
         5 . The subassembly of  claim 1 , wherein said body portion includes a polymer encapsulating at least a portion of said trigger means.  
     
     
         6 . The subassembly of  claim 1 , wherein said trigger means includes electronics for processing said ignition signal.  
     
     
         7 . The subassembly of  claim 6 , wherein said electronics include a circuit board having electrical components.  
     
     
         8 . The subassembly of  claim 7 , wherein said electronics further include an off-the-shelf cylindrical capacitor that is substantially aligned with said circuit board.  
     
     
         9 . The subassembly of  claim 6 , wherein said body portion includes a polymer encapsulating said circuit board and electrical components.  
     
     
         10 . The subassembly of  claim 9 , wherein said trigger means includes one or more electrical leads protruding out through said polymer at said trigger end.  
     
     
         11 . The subassembly of  claim 1 , wherein said detonator charge comprises a primary charge and a base charge.  
     
     
         12 . The subassembly of  claim 10 , wherein said one or more electrical leads includes a female adapter formed to securely receive the end of a pin or straight wire.  
     
     
         13 . The subassembly of  claim 1 , wherein said body portion includes a vibration damping feature to reduce the transmission of vibrations from said shell into said trigger means and ignition element when said standalone ignition subassembly is secured within the shell.  
     
     
         14 . The subassembly of  claim 13 , wherein said vibration damping feature includes one or more protuberances made of a poylmer and formed in the shape of nubs or ridges distributed on the outer surface of said body portion.  
     
     
         15 . The subassembly of  claim 14 , wherein said protuberances are distributed on the outer surface of said body portion in a circular, longitudinal, or spiral pattern.  
     
     
         16 . A method of making a standalone ignition subassembly for use with a detonator shell having a standard inner shell diameter and a detonator charge within said shell, comprising the following steps: 
 a) providing a hermetically sealed ignition element including a charge enclosure that is hermetically sealed and substantially filled with an ignition charge;    b) providing a substantially cylindrical body portion having first and second ends, and an outer diameter selected to closely match the detonator shell's standard inner shell diameter;    c) attaching said ignition element to the first end of said body portion; and,    d) providing a trigger means for causing said ignition element to ignite in response to an ignition signal, and locating at least a portion of said trigger means at said second end of said body portion.    
     
     
         17 . The method of  claim 16 , wherein step d) includes the step of providing electronics for processing said ignition signal.  
     
     
         18 . The method of  claim 17 , wherein step b) includes the step of encapsulating said electronics.  
     
     
         19 . A method of making a detonator, comprising the following steps: 
 a) selecting a standard detonator shell having a detonator charge and a predetermined inner diameter;    b) providing a standalone ignition subassembly having a hermetically sealed ignition element and a cylindrical body portion with an outer diameter selected to closely match said predetermined inner diameter of said detonator shell;    c) pushing said standalone ignition subassembly into said shell; and,    d) securing said standalone ignition subassembly within said shell.    
     
     
         20 . The method of  claim 19 , wherein step d) includes the step of inserting a body plug into said shell and crimping said shell to said body plug.