| abstract |
An initiator ( 14 c ) for a secondary explosive receptor charge is provided by forming a length of detonating cord ( 14 ) into a helical coil containing a plurality of windings with a cutoff barrier provided by, e.g., a separating rib ( 46 ) between adjacent windings. The adjacent windings may be not more than about 0.5 inch (12.7 mm) apart. The detonating cord ( 14 ) may be wound about a spindle ( 16 ) which may optionally provide the separating rib ( 46 ). The coil may be a tapered coil which may define a taper angle of e.g., from about 2 to 4 degrees. Alternatively, the coil may be a cylindrical coil, or the cord may be configured in a planar spiral. Optionally, the detonating cord in the helical coil may have a core of explosive material with a loading of less than 15 grains per foot of the cord, e.g., less than 12 grains per foot of the cord, or a loading in the range of from 8 to 12 grains per foot of the cord. The coil may consume about six inches of the cord. Conversely, the detonating cord in the spiral may have a core of explosive material with a loading of at least 2.5 grains per foot, optionally at least 15 grains per foot of the cord. |