Secondary explosive detonator device

A low voltage hot wire detonator device containing all secondary type explosive and comprising:

• a body having a closed end and an internal chamber containing a donor secondary explosive therein, said body having internal threads in the open end opposite said closed end;
• hot wire means including electrical conductors extending outwardly through an aperture in said body, said hot wire means being adjacent said donor explosive and adapted to cause ignition thereof in response to a low voltage current being applied to said conductor;
• an impactor disc positioned within the chamber of said body adjacent said donor explosive so as to generally cover the same;
• barrel means having external threads for engaging the internal threads of said body, said barrel means having an elongated bore defining an air gap and a generally flat annular shoulder for contacting said impactor disc, rotation of said barrel means in a first direction relative to said body causing said barrel means to be moved toward said closed end and bring said impactor disc into contact with said donor explosive so as to tightly confine the same;
• the central portion of said impactor disc inside of said annular shoulder being sheared therefrom in response to deflagration of said donor explosive;
• said impactor disc being of a thickness and material so that the ratio of the thickness of said sheared central portion to the outer diameter of the sheared central portion is within the range of about 1/2 to about 2/3, said sheared central portion being accelerated down said bore as a unitary piece, said ratio thereof substantially preventing tumbling of the sheared central portion during travel, thereby preventing substantial escape of explosive gases between said central portion and the wall of said bore.